fs/btrfs/inode.c

   1 /*
   2  * Copyright (C) 2007 Oracle.  All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public
   6  * License v2 as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public
  14  * License along with this program; if not, write to the
  15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16  * Boston, MA 021110-1307, USA.
  17  */
  18
  19 #include <linux/kernel.h>
  20 #include <linux/bio.h>
  21 #include <linux/buffer_head.h>
  22 #include <linux/file.h>
  23 #include <linux/fs.h>
  24 #include <linux/pagemap.h>
  25 #include <linux/highmem.h>
  26 #include <linux/time.h>
  27 #include <linux/init.h>
  28 #include <linux/string.h>
  29 #include <linux/backing-dev.h>
  30 #include <linux/mpage.h>
  31 #include <linux/swap.h>
  32 #include <linux/writeback.h>
  33 #include <linux/statfs.h>
  34 #include <linux/compat.h>
  35 #include <linux/aio.h>
  36 #include <linux/bit_spinlock.h>
  37 #include <linux/xattr.h>
  38 #include <linux/posix_acl.h>
  39 #include <linux/falloc.h>
  40 #include <linux/slab.h>
  41 #include <linux/ratelimit.h>
  42 #include <linux/mount.h>
  43 #include <linux/btrfs.h>
  44 #include <linux/blkdev.h>
  45 #include <linux/posix_acl_xattr.h>
  46 #include "ctree.h"
  47 #include "disk-io.h"
  48 #include "transaction.h"
  49 #include "btrfs_inode.h"
  50 #include "print-tree.h"
  51 #include "ordered-data.h"
  52 #include "xattr.h"
  53 #include "tree-log.h"
  54 #include "volumes.h"
  55 #include "compression.h"
  56 #include "locking.h"
  57 #include "free-space-cache.h"
  58 #include "inode-map.h"
  59 #include "backref.h"
  60 #include "hash.h"
  61 #include "props.h"
  62
  63 struct btrfs_iget_args {
  64         struct btrfs_key *location;
  65         struct btrfs_root *root;
  66 };
  67
  68 static const struct inode_operations btrfs_dir_inode_operations;
  69 static const struct inode_operations btrfs_symlink_inode_operations;
  70 static const struct inode_operations btrfs_dir_ro_inode_operations;
  71 static const struct inode_operations btrfs_special_inode_operations;
  72 static const struct inode_operations btrfs_file_inode_operations;
  73 static const struct address_space_operations btrfs_aops;
  74 static const struct address_space_operations btrfs_symlink_aops;
  75 static const struct file_operations btrfs_dir_file_operations;
  76 static struct extent_io_ops btrfs_extent_io_ops;
  77
  78 static struct kmem_cache *btrfs_inode_cachep;
  79 static struct kmem_cache *btrfs_delalloc_work_cachep;
  80 struct kmem_cache *btrfs_trans_handle_cachep;
  81 struct kmem_cache *btrfs_transaction_cachep;
  82 struct kmem_cache *btrfs_path_cachep;
  83 struct kmem_cache *btrfs_free_space_cachep;
  84
  85 #define S_SHIFT 12
  86 static unsigned char btrfs_type_by_mode[S_IFMT >> S_SHIFT] = {
  87         [S_IFREG >> S_SHIFT]    = BTRFS_FT_REG_FILE,
  88         [S_IFDIR >> S_SHIFT]    = BTRFS_FT_DIR,
  89         [S_IFCHR >> S_SHIFT]    = BTRFS_FT_CHRDEV,
  90         [S_IFBLK >> S_SHIFT]    = BTRFS_FT_BLKDEV,
  91         [S_IFIFO >> S_SHIFT]    = BTRFS_FT_FIFO,
  92         [S_IFSOCK >> S_SHIFT]   = BTRFS_FT_SOCK,
  93         [S_IFLNK >> S_SHIFT]    = BTRFS_FT_SYMLINK,
  94 };
  95
  96 static int btrfs_setsize(struct inode *inode, struct iattr *attr);
  97 static int btrfs_truncate(struct inode *inode);
  98 static int btrfs_finish_ordered_io(struct btrfs_ordered_extent *ordered_extent);
  99 static noinline int cow_file_range(struct inode *inode,
 100                                    struct page *locked_page,
 101                                    u64 start, u64 end, int *page_started,
 102                                    unsigned long *nr_written, int unlock);
 103 static struct extent_map *create_pinned_em(struct inode *inode, u64 start,
 104                                            u64 len, u64 orig_start,
 105                                            u64 block_start, u64 block_len,
 106                                            u64 orig_block_len, u64 ram_bytes,
 107                                            int type);
 108
 109 static int btrfs_dirty_inode(struct inode *inode);
 110
 111 static int btrfs_init_inode_security(struct btrfs_trans_handle *trans,
 112                                      struct inode *inode,  struct inode *dir,
 113                                      const struct qstr *qstr)
 114 {
 115         int err;
 116
 117         err = btrfs_init_acl(trans, inode, dir);
 118         if (!err)
 119                 err = btrfs_xattr_security_init(trans, inode, dir, qstr);
 120         return err;
 121 }
 122
 123 /*
 124  * this does all the hard work for inserting an inline extent into
 125  * the btree.  The caller should have done a btrfs_drop_extents so that
 126  * no overlapping inline items exist in the btree
 127  */
 128 static int insert_inline_extent(struct btrfs_trans_handle *trans,
 129                                 struct btrfs_path *path, int extent_inserted,
 130                                 struct btrfs_root *root, struct inode *inode,
 131                                 u64 start, size_t size, size_t compressed_size,
 132                                 int compress_type,
 133                                 struct page **compressed_pages)
 134 {
 135         struct extent_buffer *leaf;
 136         struct page *page = NULL;
 137         char *kaddr;
 138         unsigned long ptr;
 139         struct btrfs_file_extent_item *ei;
 140         int err = 0;
 141         int ret;
 142         size_t cur_size = size;
 143         unsigned long offset;
 144
 145         if (compressed_size && compressed_pages)
 146                 cur_size = compressed_size;
 147
 148         inode_add_bytes(inode, size);
 149
 150         if (!extent_inserted) {
 151                 struct btrfs_key key;
 152                 size_t datasize;
 153
 154                 key.objectid = btrfs_ino(inode);
 155                 key.offset = start;
 156                 btrfs_set_key_type(&key, BTRFS_EXTENT_DATA_KEY);
 157
 158                 datasize = btrfs_file_extent_calc_inline_size(cur_size);
 159                 path->leave_spinning = 1;
 160                 ret = btrfs_insert_empty_item(trans, root, path, &key,
 161                                               datasize);
 162                 if (ret) {
 163                         err = ret;
 164                         goto fail;
 165                 }
 166         }
 167         leaf = path->nodes[0];
 168         ei = btrfs_item_ptr(leaf, path->slots[0],
 169                             struct btrfs_file_extent_item);
 170         btrfs_set_file_extent_generation(leaf, ei, trans->transid);
 171         btrfs_set_file_extent_type(leaf, ei, BTRFS_FILE_EXTENT_INLINE);
 172         btrfs_set_file_extent_encryption(leaf, ei, 0);
 173         btrfs_set_file_extent_other_encoding(leaf, ei, 0);
 174         btrfs_set_file_extent_ram_bytes(leaf, ei, size);
 175         ptr = btrfs_file_extent_inline_start(ei);
 176
 177         if (compress_type != BTRFS_COMPRESS_NONE) {
 178                 struct page *cpage;
 179                 int i = 0;
 180                 while (compressed_size > 0) {
 181                         cpage = compressed_pages[i];
 182                         cur_size = min_t(unsigned long, compressed_size,
 183                                        PAGE_CACHE_SIZE);
 184
 185                         kaddr = kmap_atomic(cpage);
 186                         write_extent_buffer(leaf, kaddr, ptr, cur_size);
 187                         kunmap_atomic(kaddr);
 188
 189                         i++;
 190                         ptr += cur_size;
 191                         compressed_size -= cur_size;
 192                 }
 193                 btrfs_set_file_extent_compression(leaf, ei,
 194                                                   compress_type);
 195         } else {
 196                 page = find_get_page(inode->i_mapping,
 197                                      start >> PAGE_CACHE_SHIFT);
 198                 btrfs_set_file_extent_compression(leaf, ei, 0);
 199                 kaddr = kmap_atomic(page);
 200                 offset = start & (PAGE_CACHE_SIZE - 1);
 201                 write_extent_buffer(leaf, kaddr + offset, ptr, size);
 202                 kunmap_atomic(kaddr);
 203                 page_cache_release(page);
 204         }
 205         btrfs_mark_buffer_dirty(leaf);
 206         btrfs_release_path(path);
 207
 208         /*
 209          * we're an inline extent, so nobody can
 210          * extend the file past i_size without locking
 211          * a page we already have locked.
 212          *
 213          * We must do any isize and inode updates
 214          * before we unlock the pages.  Otherwise we
 215          * could end up racing with unlink.
 216          */
 217         BTRFS_I(inode)->disk_i_size = inode->i_size;
 218         ret = btrfs_update_inode(trans, root, inode);
 219
 220         return ret;
 221 fail:
 222         return err;
 223 }
 224
 225
 226 /*
 227  * conditionally insert an inline extent into the file.  This
 228  * does the checks required to make sure the data is small enough
 229  * to fit as an inline extent.
 230  */
 231 static noinline int cow_file_range_inline(struct btrfs_root *root,
 232                                           struct inode *inode, u64 start,
 233                                           u64 end, size_t compressed_size,
 234                                           int compress_type,
 235                                           struct page **compressed_pages)
 236 {
 237         struct btrfs_trans_handle *trans;
 238         u64 isize = i_size_read(inode);
 239         u64 actual_end = min(end + 1, isize);
 240         u64 inline_len = actual_end - start;
 241         u64 aligned_end = ALIGN(end, root->sectorsize);
 242         u64 data_len = inline_len;
 243         int ret;
 244         struct btrfs_path *path;
 245         int extent_inserted = 0;
 246         u32 extent_item_size;
 247
 248         if (compressed_size)
 249                 data_len = compressed_size;
 250
 251         if (start > 0 ||
 252             actual_end >= PAGE_CACHE_SIZE ||
 253             data_len >= BTRFS_MAX_INLINE_DATA_SIZE(root) ||
 254             (!compressed_size &&
 255             (actual_end & (root->sectorsize - 1)) == 0) ||
 256             end + 1 < isize ||
 257             data_len > root->fs_info->max_inline) {
 258                 return 1;
 259         }
 260
 261         path = btrfs_alloc_path();
 262         if (!path)
 263                 return -ENOMEM;
 264
 265         trans = btrfs_join_transaction(root);
 266         if (IS_ERR(trans)) {
 267                 btrfs_free_path(path);
 268                 return PTR_ERR(trans);
 269         }
 270         trans->block_rsv = &root->fs_info->delalloc_block_rsv;
 271
 272         if (compressed_size && compressed_pages)
 273                 extent_item_size = btrfs_file_extent_calc_inline_size(
 274                    compressed_size);
 275         else
 276                 extent_item_size = btrfs_file_extent_calc_inline_size(
 277                     inline_len);
 278
 279         ret = __btrfs_drop_extents(trans, root, inode, path,
 280                                    start, aligned_end, NULL,
 281                                    1, 1, extent_item_size, &extent_inserted);
 282         if (ret) {
 283                 btrfs_abort_transaction(trans, root, ret);
 284                 goto out;
 285         }
 286
 287         if (isize > actual_end)
 288                 inline_len = min_t(u64, isize, actual_end);
 289         ret = insert_inline_extent(trans, path, extent_inserted,
 290                                    root, inode, start,
 291                                    inline_len, compressed_size,
 292                                    compress_type, compressed_pages);
 293         if (ret && ret != -ENOSPC) {
 294                 btrfs_abort_transaction(trans, root, ret);
 295                 goto out;
 296         } else if (ret == -ENOSPC) {
 297                 ret = 1;
 298                 goto out;
 299         }
 300
 301         set_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &BTRFS_I(inode)->runtime_flags);
 302         btrfs_delalloc_release_metadata(inode, end + 1 - start);
 303         btrfs_drop_extent_cache(inode, start, aligned_end - 1, 0);
 304 out:
 305         btrfs_free_path(path);
 306         btrfs_end_transaction(trans, root);
 307         return ret;
 308 }
 309
 310 struct async_extent {
 311         u64 start;
 312         u64 ram_size;
 313         u64 compressed_size;
 314         struct page **pages;
 315         unsigned long nr_pages;
 316         int compress_type;
 317         struct list_head list;
 318 };
 319
 320 struct async_cow {
 321         struct inode *inode;
 322         struct btrfs_root *root;
 323         struct page *locked_page;
 324         u64 start;
 325         u64 end;
 326         struct list_head extents;
 327         struct btrfs_work work;
 328 };
 329
 330 static noinline int add_async_extent(struct async_cow *cow,
 331                                      u64 start, u64 ram_size,
 332                                      u64 compressed_size,
 333                                      struct page **pages,
 334                                      unsigned long nr_pages,
 335                                      int compress_type)
 336 {
 337         struct async_extent *async_extent;
 338
 339         async_extent = kmalloc(sizeof(*async_extent), GFP_NOFS);
 340         BUG_ON(!async_extent); /* -ENOMEM */
 341         async_extent->start = start;
 342         async_extent->ram_size = ram_size;
 343         async_extent->compressed_size = compressed_size;
 344         async_extent->pages = pages;
 345         async_extent->nr_pages = nr_pages;
 346         async_extent->compress_type = compress_type;
 347         list_add_tail(&async_extent->list, &cow->extents);
 348         return 0;
 349 }
 350
 351 /*
 352  * we create compressed extents in two phases.  The first
 353  * phase compresses a range of pages that have already been
 354  * locked (both pages and state bits are locked).
 355  *
 356  * This is done inside an ordered work queue, and the compression
 357  * is spread across many cpus.  The actual IO submission is step
 358  * two, and the ordered work queue takes care of making sure that
 359  * happens in the same order things were put onto the queue by
 360  * writepages and friends.
 361  *
 362  * If this code finds it can't get good compression, it puts an
 363  * entry onto the work queue to write the uncompressed bytes.  This
 364  * makes sure that both compressed inodes and uncompressed inodes
 365  * are written in the same order that the flusher thread sent them
 366  * down.
 367  */
 368 static noinline int compress_file_range(struct inode *inode,
 369                                         struct page *locked_page,
 370                                         u64 start, u64 end,
 371                                         struct async_cow *async_cow,
 372                                         int *num_added)
 373 {
 374         struct btrfs_root *root = BTRFS_I(inode)->root;
 375         u64 num_bytes;
 376         u64 blocksize = root->sectorsize;
 377         u64 actual_end;
 378         u64 isize = i_size_read(inode);
 379         int ret = 0;
 380         struct page **pages = NULL;
 381         unsigned long nr_pages;
 382         unsigned long nr_pages_ret = 0;
 383         unsigned long total_compressed = 0;
 384         unsigned long total_in = 0;
 385         unsigned long max_compressed = 128 * 1024;
 386         unsigned long max_uncompressed = 128 * 1024;
 387         int i;
 388         int will_compress;
 389         int compress_type = root->fs_info->compress_type;
 390         int redirty = 0;
 391
 392         /* if this is a small write inside eof, kick off a defrag */
 393         if ((end - start + 1) < 16 * 1024 &&
 394             (start > 0 || end + 1 < BTRFS_I(inode)->disk_i_size))
 395                 btrfs_add_inode_defrag(NULL, inode);
 396
 397         /*
 398          * skip compression for a small file range(<=blocksize) that
 399          * isn't an inline extent, since it dosen't save disk space at all.
 400          */
 401         if ((end - start + 1) <= blocksize &&
 402             (start > 0 || end + 1 < BTRFS_I(inode)->disk_i_size))
 403                 goto cleanup_and_bail_uncompressed;
 404
 405         actual_end = min_t(u64, isize, end + 1);
 406 again:
 407         will_compress = 0;
 408         nr_pages = (end >> PAGE_CACHE_SHIFT) - (start >> PAGE_CACHE_SHIFT) + 1;
 409         nr_pages = min(nr_pages, (128 * 1024UL) / PAGE_CACHE_SIZE);
 410
 411         /*
 412          * we don't want to send crud past the end of i_size through
 413          * compression, that's just a waste of CPU time.  So, if the
 414          * end of the file is before the start of our current
 415          * requested range of bytes, we bail out to the uncompressed
 416          * cleanup code that can deal with all of this.
 417          *
 418          * It isn't really the fastest way to fix things, but this is a
 419          * very uncommon corner.
 420          */
 421         if (actual_end <= start)
 422                 goto cleanup_and_bail_uncompressed;
 423
 424         total_compressed = actual_end - start;
 425
 426         /* we want to make sure that amount of ram required to uncompress
 427          * an extent is reasonable, so we limit the total size in ram
 428          * of a compressed extent to 128k.  This is a crucial number
 429          * because it also controls how easily we can spread reads across
 430          * cpus for decompression.
 431          *
 432          * We also want to make sure the amount of IO required to do
 433          * a random read is reasonably small, so we limit the size of
 434          * a compressed extent to 128k.
 435          */
 436         total_compressed = min(total_compressed, max_uncompressed);
 437         num_bytes = ALIGN(end - start + 1, blocksize);
 438         num_bytes = max(blocksize,  num_bytes);
 439         total_in = 0;
 440         ret = 0;
 441
 442         /*
 443          * we do compression for mount -o compress and when the
 444          * inode has not been flagged as nocompress.  This flag can
 445          * change at any time if we discover bad compression ratios.
 446          */
 447         if (!(BTRFS_I(inode)->flags & BTRFS_INODE_NOCOMPRESS) &&
 448             (btrfs_test_opt(root, COMPRESS) ||
 449              (BTRFS_I(inode)->force_compress) ||
 450              (BTRFS_I(inode)->flags & BTRFS_INODE_COMPRESS))) {
 451                 WARN_ON(pages);
 452                 pages = kzalloc(sizeof(struct page *) * nr_pages, GFP_NOFS);
 453                 if (!pages) {
 454                         /* just bail out to the uncompressed code */
 455                         goto cont;
 456                 }
 457
 458                 if (BTRFS_I(inode)->force_compress)
 459                         compress_type = BTRFS_I(inode)->force_compress;
 460
 461                 /*
 462                  * we need to call clear_page_dirty_for_io on each
 463                  * page in the range.  Otherwise applications with the file
 464                  * mmap'd can wander in and change the page contents while
 465                  * we are compressing them.
 466                  *
 467                  * If the compression fails for any reason, we set the pages
 468                  * dirty again later on.
 469                  */
 470                 extent_range_clear_dirty_for_io(inode, start, end);
 471                 redirty = 1;
 472                 ret = btrfs_compress_pages(compress_type,
 473                                            inode->i_mapping, start,
 474                                            total_compressed, pages,
 475                                            nr_pages, &nr_pages_ret,
 476                                            &total_in,
 477                                            &total_compressed,
 478                                            max_compressed);
 479
 480                 if (!ret) {
 481                         unsigned long offset = total_compressed &
 482                                 (PAGE_CACHE_SIZE - 1);
 483                         struct page *page = pages[nr_pages_ret - 1];
 484                         char *kaddr;
 485
 486                         /* zero the tail end of the last page, we might be
 487                          * sending it down to disk
 488                          */
 489                         if (offset) {
 490                                 kaddr = kmap_atomic(page);
 491                                 memset(kaddr + offset, 0,
 492                                        PAGE_CACHE_SIZE - offset);
 493                                 kunmap_atomic(kaddr);
 494                         }
 495                         will_compress = 1;
 496                 }
 497         }
 498 cont:
 499         if (start == 0) {
 500                 /* lets try to make an inline extent */
 501                 if (ret || total_in < (actual_end - start)) {
 502                         /* we didn't compress the entire range, try
 503                          * to make an uncompressed inline extent.
 504                          */
 505                         ret = cow_file_range_inline(root, inode, start, end,
 506                                                     0, 0, NULL);
 507                 } else {
 508                         /* try making a compressed inline extent */
 509                         ret = cow_file_range_inline(root, inode, start, end,
 510                                                     total_compressed,
 511                                                     compress_type, pages);
 512                 }
 513                 if (ret <= 0) {
 514                         unsigned long clear_flags = EXTENT_DELALLOC |
 515                                 EXTENT_DEFRAG;
 516                         clear_flags |= (ret < 0) ? EXTENT_DO_ACCOUNTING : 0;
 517
 518                         /*
 519                          * inline extent creation worked or returned error,
 520                          * we don't need to create any more async work items.
 521                          * Unlock and free up our temp pages.
 522                          */
 523                         extent_clear_unlock_delalloc(inode, start, end, NULL,
 524                                                      clear_flags, PAGE_UNLOCK |
 525                                                      PAGE_CLEAR_DIRTY |
 526                                                      PAGE_SET_WRITEBACK |
 527                                                      PAGE_END_WRITEBACK);
 528                         goto free_pages_out;
 529                 }
 530         }
 531
 532         if (will_compress) {
 533                 /*
 534                  * we aren't doing an inline extent round the compressed size
 535                  * up to a block size boundary so the allocator does sane
 536                  * things
 537                  */
 538                 total_compressed = ALIGN(total_compressed, blocksize);
 539
 540                 /*
 541                  * one last check to make sure the compression is really a
 542                  * win, compare the page count read with the blocks on disk
 543                  */
 544                 total_in = ALIGN(total_in, PAGE_CACHE_SIZE);
 545                 if (total_compressed >= total_in) {
 546                         will_compress = 0;
 547                 } else {
 548                         num_bytes = total_in;
 549                 }
 550         }
 551         if (!will_compress && pages) {
 552                 /*
 553                  * the compression code ran but failed to make things smaller,
 554                  * free any pages it allocated and our page pointer array
 555                  */
 556                 for (i = 0; i < nr_pages_ret; i++) {
 557                         WARN_ON(pages[i]->mapping);
 558                         page_cache_release(pages[i]);
 559                 }
 560                 kfree(pages);
 561                 pages = NULL;
 562                 total_compressed = 0;
 563                 nr_pages_ret = 0;
 564
 565                 /* flag the file so we don't compress in the future */
 566                 if (!btrfs_test_opt(root, FORCE_COMPRESS) &&
 567                     !(BTRFS_I(inode)->force_compress)) {
 568                         BTRFS_I(inode)->flags |= BTRFS_INODE_NOCOMPRESS;
 569                 }
 570         }
 571         if (will_compress) {
 572                 *num_added += 1;
 573
 574                 /* the async work queues will take care of doing actual
 575                  * allocation on disk for these compressed pages,
 576                  * and will submit them to the elevator.
 577                  */
 578                 add_async_extent(async_cow, start, num_bytes,
 579                                  total_compressed, pages, nr_pages_ret,
 580                                  compress_type);
 581
 582                 if (start + num_bytes < end) {
 583                         start += num_bytes;
 584                         pages = NULL;
 585                         cond_resched();
 586                         goto again;
 587                 }
 588         } else {
 589 cleanup_and_bail_uncompressed:
 590                 /*
 591                  * No compression, but we still need to write the pages in
 592                  * the file we've been given so far.  redirty the locked
 593                  * page if it corresponds to our extent and set things up
 594                  * for the async work queue to run cow_file_range to do
 595                  * the normal delalloc dance
 596                  */
 597                 if (page_offset(locked_page) >= start &&
 598                     page_offset(locked_page) <= end) {
 599                         __set_page_dirty_nobuffers(locked_page);
 600                         /* unlocked later on in the async handlers */
 601                 }
 602                 if (redirty)
 603                         extent_range_redirty_for_io(inode, start, end);
 604                 add_async_extent(async_cow, start, end - start + 1,
 605                                  0, NULL, 0, BTRFS_COMPRESS_NONE);
 606                 *num_added += 1;
 607         }
 608
 609 out:
 610         return ret;
 611
 612 free_pages_out:
 613         for (i = 0; i < nr_pages_ret; i++) {
 614                 WARN_ON(pages[i]->mapping);
 615                 page_cache_release(pages[i]);
 616         }
 617         kfree(pages);
 618
 619         goto out;
 620 }
 621
 622 /*
 623  * phase two of compressed writeback.  This is the ordered portion
 624  * of the code, which only gets called in the order the work was
 625  * queued.  We walk all the async extents created by compress_file_range
 626  * and send them down to the disk.
 627  */
 628 static noinline int submit_compressed_extents(struct inode *inode,
 629                                               struct async_cow *async_cow)
 630 {
 631         struct async_extent *async_extent;
 632         u64 alloc_hint = 0;
 633         struct btrfs_key ins;
 634         struct extent_map *em;
 635         struct btrfs_root *root = BTRFS_I(inode)->root;
 636         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
 637         struct extent_io_tree *io_tree;
 638         int ret = 0;
 639
 640         if (list_empty(&async_cow->extents))
 641                 return 0;
 642
 643 again:
 644         while (!list_empty(&async_cow->extents)) {
 645                 async_extent = list_entry(async_cow->extents.next,
 646                                           struct async_extent, list);
 647                 list_del(&async_extent->list);
 648
 649                 io_tree = &BTRFS_I(inode)->io_tree;
 650
 651 retry:
 652                 /* did the compression code fall back to uncompressed IO? */
 653                 if (!async_extent->pages) {
 654                         int page_started = 0;
 655                         unsigned long nr_written = 0;
 656
 657                         lock_extent(io_tree, async_extent->start,
 658                                          async_extent->start +
 659                                          async_extent->ram_size - 1);
 660
 661                         /* allocate blocks */
 662                         ret = cow_file_range(inode, async_cow->locked_page,
 663                                              async_extent->start,
 664                                              async_extent->start +
 665                                              async_extent->ram_size - 1,
 666                                              &page_started, &nr_written, 0);
 667
 668                         /* JDM XXX */
 669
 670                         /*
 671                          * if page_started, cow_file_range inserted an
 672                          * inline extent and took care of all the unlocking
 673                          * and IO for us.  Otherwise, we need to submit
 674                          * all those pages down to the drive.
 675                          */
 676                         if (!page_started && !ret)
 677                                 extent_write_locked_range(io_tree,
 678                                                   inode, async_extent->start,
 679                                                   async_extent->start +
 680                                                   async_extent->ram_size - 1,
 681                                                   btrfs_get_extent,
 682                                                   WB_SYNC_ALL);
 683                         else if (ret)
 684                                 unlock_page(async_cow->locked_page);
 685                         kfree(async_extent);
 686                         cond_resched();
 687                         continue;
 688                 }
 689
 690                 lock_extent(io_tree, async_extent->start,
 691                             async_extent->start + async_extent->ram_size - 1);
 692
 693                 ret = btrfs_reserve_extent(root,
 694                                            async_extent->compressed_size,
 695                                            async_extent->compressed_size,
 696                                            0, alloc_hint, &ins, 1, 1);
 697                 if (ret) {
 698                         int i;
 699
 700                         for (i = 0; i < async_extent->nr_pages; i++) {
 701                                 WARN_ON(async_extent->pages[i]->mapping);
 702                                 page_cache_release(async_extent->pages[i]);
 703                         }
 704                         kfree(async_extent->pages);
 705                         async_extent->nr_pages = 0;
 706                         async_extent->pages = NULL;
 707
 708                         if (ret == -ENOSPC) {
 709                                 unlock_extent(io_tree, async_extent->start,
 710                                               async_extent->start +
 711                                               async_extent->ram_size - 1);
 712
 713                                 /*
 714                                  * we need to redirty the pages if we decide to
 715                                  * fallback to uncompressed IO, otherwise we
 716                                  * will not submit these pages down to lower
 717                                  * layers.
 718                                  */
 719                                 extent_range_redirty_for_io(inode,
 720                                                 async_extent->start,
 721                                                 async_extent->start +
 722                                                 async_extent->ram_size - 1);
 723
 724                                 goto retry;
 725                         }
 726                         goto out_free;
 727                 }
 728
 729                 /*
 730                  * here we're doing allocation and writeback of the
 731                  * compressed pages
 732                  */
 733                 btrfs_drop_extent_cache(inode, async_extent->start,
 734                                         async_extent->start +
 735                                         async_extent->ram_size - 1, 0);
 736
 737                 em = alloc_extent_map();
 738                 if (!em) {
 739                         ret = -ENOMEM;
 740                         goto out_free_reserve;
 741                 }
 742                 em->start = async_extent->start;
 743                 em->len = async_extent->ram_size;
 744                 em->orig_start = em->start;
 745                 em->mod_start = em->start;
 746                 em->mod_len = em->len;
 747
 748                 em->block_start = ins.objectid;
 749                 em->block_len = ins.offset;
 750                 em->orig_block_len = ins.offset;
 751                 em->ram_bytes = async_extent->ram_size;
 752                 em->bdev = root->fs_info->fs_devices->latest_bdev;
 753                 em->compress_type = async_extent->compress_type;
 754                 set_bit(EXTENT_FLAG_PINNED, &em->flags);
 755                 set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
 756                 em->generation = -1;
 757
 758                 while (1) {
 759                         write_lock(&em_tree->lock);
 760                         ret = add_extent_mapping(em_tree, em, 1);
 761                         write_unlock(&em_tree->lock);
 762                         if (ret != -EEXIST) {
 763                                 free_extent_map(em);
 764                                 break;
 765                         }
 766                         btrfs_drop_extent_cache(inode, async_extent->start,
 767                                                 async_extent->start +
 768                                                 async_extent->ram_size - 1, 0);
 769                 }
 770
 771                 if (ret)
 772                         goto out_free_reserve;
 773
 774                 ret = btrfs_add_ordered_extent_compress(inode,
 775                                                 async_extent->start,
 776                                                 ins.objectid,
 777                                                 async_extent->ram_size,
 778                                                 ins.offset,
 779                                                 BTRFS_ORDERED_COMPRESSED,
 780                                                 async_extent->compress_type);
 781                 if (ret)
 782                         goto out_free_reserve;
 783
 784                 /*
 785                  * clear dirty, set writeback and unlock the pages.
 786                  */
 787                 extent_clear_unlock_delalloc(inode, async_extent->start,
 788                                 async_extent->start +
 789                                 async_extent->ram_size - 1,
 790                                 NULL, EXTENT_LOCKED | EXTENT_DELALLOC,
 791                                 PAGE_UNLOCK | PAGE_CLEAR_DIRTY |
 792                                 PAGE_SET_WRITEBACK);
 793                 ret = btrfs_submit_compressed_write(inode,
 794                                     async_extent->start,
 795                                     async_extent->ram_size,
 796                                     ins.objectid,
 797                                     ins.offset, async_extent->pages,
 798                                     async_extent->nr_pages);
 799                 alloc_hint = ins.objectid + ins.offset;
 800                 kfree(async_extent);
 801                 if (ret)
 802                         goto out;
 803                 cond_resched();
 804         }
 805         ret = 0;
 806 out:
 807         return ret;
 808 out_free_reserve:
 809         btrfs_free_reserved_extent(root, ins.objectid, ins.offset, 1);
 810 out_free:
 811         extent_clear_unlock_delalloc(inode, async_extent->start,
 812                                      async_extent->start +
 813                                      async_extent->ram_size - 1,
 814                                      NULL, EXTENT_LOCKED | EXTENT_DELALLOC |
 815                                      EXTENT_DEFRAG | EXTENT_DO_ACCOUNTING,
 816                                      PAGE_UNLOCK | PAGE_CLEAR_DIRTY |
 817                                      PAGE_SET_WRITEBACK | PAGE_END_WRITEBACK);
 818         kfree(async_extent);
 819         goto again;
 820 }
 821
 822 static u64 get_extent_allocation_hint(struct inode *inode, u64 start,
 823                                       u64 num_bytes)
 824 {
 825         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
 826         struct extent_map *em;
 827         u64 alloc_hint = 0;
 828
 829         read_lock(&em_tree->lock);
 830         em = search_extent_mapping(em_tree, start, num_bytes);
 831         if (em) {
 832                 /*
 833                  * if block start isn't an actual block number then find the
 834                  * first block in this inode and use that as a hint.  If that
 835                  * block is also bogus then just don't worry about it.
 836                  */
 837                 if (em->block_start >= EXTENT_MAP_LAST_BYTE) {
 838                         free_extent_map(em);
 839                         em = search_extent_mapping(em_tree, 0, 0);
 840                         if (em && em->block_start < EXTENT_MAP_LAST_BYTE)
 841                                 alloc_hint = em->block_start;
 842                         if (em)
 843                                 free_extent_map(em);
 844                 } else {
 845                         alloc_hint = em->block_start;
 846                         free_extent_map(em);
 847                 }
 848         }
 849         read_unlock(&em_tree->lock);
 850
 851         return alloc_hint;
 852 }
 853
 854 /*
 855  * when extent_io.c finds a delayed allocation range in the file,
 856  * the call backs end up in this code.  The basic idea is to
 857  * allocate extents on disk for the range, and create ordered data structs
 858  * in ram to track those extents.
 859  *
 860  * locked_page is the page that writepage had locked already.  We use
 861  * it to make sure we don't do extra locks or unlocks.
 862  *
 863  * *page_started is set to one if we unlock locked_page and do everything
 864  * required to start IO on it.  It may be clean and already done with
 865  * IO when we return.
 866  */
 867 static noinline int cow_file_range(struct inode *inode,
 868                                    struct page *locked_page,
 869                                    u64 start, u64 end, int *page_started,
 870                                    unsigned long *nr_written,
 871                                    int unlock)
 872 {
 873         struct btrfs_root *root = BTRFS_I(inode)->root;
 874         u64 alloc_hint = 0;
 875         u64 num_bytes;
 876         unsigned long ram_size;
 877         u64 disk_num_bytes;
 878         u64 cur_alloc_size;
 879         u64 blocksize = root->sectorsize;
 880         struct btrfs_key ins;
 881         struct extent_map *em;
 882         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
 883         int ret = 0;
 884
 885         if (btrfs_is_free_space_inode(inode)) {
 886                 WARN_ON_ONCE(1);
 887                 ret = -EINVAL;
 888                 goto out_unlock;
 889         }
 890
 891         num_bytes = ALIGN(end - start + 1, blocksize);
 892         num_bytes = max(blocksize,  num_bytes);
 893         disk_num_bytes = num_bytes;
 894
 895         /* if this is a small write inside eof, kick off defrag */
 896         if (num_bytes < 64 * 1024 &&
 897             (start > 0 || end + 1 < BTRFS_I(inode)->disk_i_size))
 898                 btrfs_add_inode_defrag(NULL, inode);
 899
 900         if (start == 0) {
 901                 /* lets try to make an inline extent */
 902                 ret = cow_file_range_inline(root, inode, start, end, 0, 0,
 903                                             NULL);
 904                 if (ret == 0) {
 905                         extent_clear_unlock_delalloc(inode, start, end, NULL,
 906                                      EXTENT_LOCKED | EXTENT_DELALLOC |
 907                                      EXTENT_DEFRAG, PAGE_UNLOCK |
 908                                      PAGE_CLEAR_DIRTY | PAGE_SET_WRITEBACK |
 909                                      PAGE_END_WRITEBACK);
 910
 911                         *nr_written = *nr_written +
 912                              (end - start + PAGE_CACHE_SIZE) / PAGE_CACHE_SIZE;
 913                         *page_started = 1;
 914                         goto out;
 915                 } else if (ret < 0) {
 916                         goto out_unlock;
 917                 }
 918         }
 919
 920         BUG_ON(disk_num_bytes >
 921                btrfs_super_total_bytes(root->fs_info->super_copy));
 922
 923         alloc_hint = get_extent_allocation_hint(inode, start, num_bytes);
 924         btrfs_drop_extent_cache(inode, start, start + num_bytes - 1, 0);
 925
 926         while (disk_num_bytes > 0) {
 927                 unsigned long op;
 928
 929                 cur_alloc_size = disk_num_bytes;
 930                 ret = btrfs_reserve_extent(root, cur_alloc_size,
 931                                            root->sectorsize, 0, alloc_hint,
 932                                            &ins, 1, 1);
 933                 if (ret < 0)
 934                         goto out_unlock;
 935
 936                 em = alloc_extent_map();
 937                 if (!em) {
 938                         ret = -ENOMEM;
 939                         goto out_reserve;
 940                 }
 941                 em->start = start;
 942                 em->orig_start = em->start;
 943                 ram_size = ins.offset;
 944                 em->len = ins.offset;
 945                 em->mod_start = em->start;
 946                 em->mod_len = em->len;
 947
 948                 em->block_start = ins.objectid;
 949                 em->block_len = ins.offset;
 950                 em->orig_block_len = ins.offset;
 951                 em->ram_bytes = ram_size;
 952                 em->bdev = root->fs_info->fs_devices->latest_bdev;
 953                 set_bit(EXTENT_FLAG_PINNED, &em->flags);
 954                 em->generation = -1;
 955
 956                 while (1) {
 957                         write_lock(&em_tree->lock);
 958                         ret = add_extent_mapping(em_tree, em, 1);
 959                         write_unlock(&em_tree->lock);
 960                         if (ret != -EEXIST) {
 961                                 free_extent_map(em);
 962                                 break;
 963                         }
 964                         btrfs_drop_extent_cache(inode, start,
 965                                                 start + ram_size - 1, 0);
 966                 }
 967                 if (ret)
 968                         goto out_reserve;
 969
 970                 cur_alloc_size = ins.offset;
 971                 ret = btrfs_add_ordered_extent(inode, start, ins.objectid,
 972                                                ram_size, cur_alloc_size, 0);
 973                 if (ret)
 974                         goto out_reserve;
 975
 976                 if (root->root_key.objectid ==
 977                     BTRFS_DATA_RELOC_TREE_OBJECTID) {
 978                         ret = btrfs_reloc_clone_csums(inode, start,
 979                                                       cur_alloc_size);
 980                         if (ret)
 981                                 goto out_reserve;
 982                 }
 983
 984                 if (disk_num_bytes < cur_alloc_size)
 985                         break;
 986
 987                 /* we're not doing compressed IO, don't unlock the first
 988                  * page (which the caller expects to stay locked), don't
 989                  * clear any dirty bits and don't set any writeback bits
 990                  *
 991                  * Do set the Private2 bit so we know this page was properly
 992                  * setup for writepage
 993                  */
 994                 op = unlock ? PAGE_UNLOCK : 0;
 995                 op |= PAGE_SET_PRIVATE2;
 996
 997                 extent_clear_unlock_delalloc(inode, start,
 998                                              start + ram_size - 1, locked_page,
 999                                              EXTENT_LOCKED | EXTENT_DELALLOC,
1000                                              op);
1001                 disk_num_bytes -= cur_alloc_size;
1002                 num_bytes -= cur_alloc_size;
1003                 alloc_hint = ins.objectid + ins.offset;
1004                 start += cur_alloc_size;
1005         }
1006 out:
1007         return ret;
1008
1009 out_reserve:
1010         btrfs_free_reserved_extent(root, ins.objectid, ins.offset, 1);
1011 out_unlock:
1012         extent_clear_unlock_delalloc(inode, start, end, locked_page,
1013                                      EXTENT_LOCKED | EXTENT_DO_ACCOUNTING |
1014                                      EXTENT_DELALLOC | EXTENT_DEFRAG,
1015                                      PAGE_UNLOCK | PAGE_CLEAR_DIRTY |
1016                                      PAGE_SET_WRITEBACK | PAGE_END_WRITEBACK);
1017         goto out;
1018 }
1019
1020 /*
1021  * work queue call back to started compression on a file and pages
1022  */
1023 static noinline void async_cow_start(struct btrfs_work *work)
1024 {
1025         struct async_cow *async_cow;
1026         int num_added = 0;
1027         async_cow = container_of(work, struct async_cow, work);
1028
1029         compress_file_range(async_cow->inode, async_cow->locked_page,
1030                             async_cow->start, async_cow->end, async_cow,
1031                             &num_added);
1032         if (num_added == 0) {
1033                 btrfs_add_delayed_iput(async_cow->inode);
1034                 async_cow->inode = NULL;
1035         }
1036 }
1037
1038 /*
1039  * work queue call back to submit previously compressed pages
1040  */
1041 static noinline void async_cow_submit(struct btrfs_work *work)
1042 {
1043         struct async_cow *async_cow;
1044         struct btrfs_root *root;
1045         unsigned long nr_pages;
1046
1047         async_cow = container_of(work, struct async_cow, work);
1048
1049         root = async_cow->root;
1050         nr_pages = (async_cow->end - async_cow->start + PAGE_CACHE_SIZE) >>
1051                 PAGE_CACHE_SHIFT;
1052
1053         if (atomic_sub_return(nr_pages, &root->fs_info->async_delalloc_pages) <
1054             5 * 1024 * 1024 &&
1055             waitqueue_active(&root->fs_info->async_submit_wait))
1056                 wake_up(&root->fs_info->async_submit_wait);
1057
1058         if (async_cow->inode)
1059                 submit_compressed_extents(async_cow->inode, async_cow);
1060 }
1061
1062 static noinline void async_cow_free(struct btrfs_work *work)
1063 {
1064         struct async_cow *async_cow;
1065         async_cow = container_of(work, struct async_cow, work);
1066         if (async_cow->inode)
1067                 btrfs_add_delayed_iput(async_cow->inode);
1068         kfree(async_cow);
1069 }
1070
1071 static int cow_file_range_async(struct inode *inode, struct page *locked_page,
1072                                 u64 start, u64 end, int *page_started,
1073                                 unsigned long *nr_written)
1074 {
1075         struct async_cow *async_cow;
1076         struct btrfs_root *root = BTRFS_I(inode)->root;
1077         unsigned long nr_pages;
1078         u64 cur_end;
1079         int limit = 10 * 1024 * 1024;
1080
1081         clear_extent_bit(&BTRFS_I(inode)->io_tree, start, end, EXTENT_LOCKED,
1082                          1, 0, NULL, GFP_NOFS);
1083         while (start < end) {
1084                 async_cow = kmalloc(sizeof(*async_cow), GFP_NOFS);
1085                 BUG_ON(!async_cow); /* -ENOMEM */
1086                 async_cow->inode = igrab(inode);
1087                 async_cow->root = root;
1088                 async_cow->locked_page = locked_page;
1089                 async_cow->start = start;
1090
1091                 if (BTRFS_I(inode)->flags & BTRFS_INODE_NOCOMPRESS)
1092                         cur_end = end;
1093                 else
1094                         cur_end = min(end, start + 512 * 1024 - 1);
1095
1096                 async_cow->end = cur_end;
1097                 INIT_LIST_HEAD(&async_cow->extents);
1098
1099                 btrfs_init_work(&async_cow->work, async_cow_start,
1100                                 async_cow_submit, async_cow_free);
1101
1102                 nr_pages = (cur_end - start + PAGE_CACHE_SIZE) >>
1103                         PAGE_CACHE_SHIFT;
1104                 atomic_add(nr_pages, &root->fs_info->async_delalloc_pages);
1105
1106                 btrfs_queue_work(root->fs_info->delalloc_workers,
1107                                  &async_cow->work);
1108
1109                 if (atomic_read(&root->fs_info->async_delalloc_pages) > limit) {
1110                         wait_event(root->fs_info->async_submit_wait,
1111                            (atomic_read(&root->fs_info->async_delalloc_pages) <
1112                             limit));
1113                 }
1114
1115                 while (atomic_read(&root->fs_info->async_submit_draining) &&
1116                       atomic_read(&root->fs_info->async_delalloc_pages)) {
1117                         wait_event(root->fs_info->async_submit_wait,
1118                           (atomic_read(&root->fs_info->async_delalloc_pages) ==
1119                            0));
1120                 }
1121
1122                 *nr_written += nr_pages;
1123                 start = cur_end + 1;
1124         }
1125         *page_started = 1;
1126         return 0;
1127 }
1128
1129 static noinline int csum_exist_in_range(struct btrfs_root *root,
1130                                         u64 bytenr, u64 num_bytes)
1131 {
1132         int ret;
1133         struct btrfs_ordered_sum *sums;
1134         LIST_HEAD(list);
1135
1136         ret = btrfs_lookup_csums_range(root->fs_info->csum_root, bytenr,
1137                                        bytenr + num_bytes - 1, &list, 0);
1138         if (ret == 0 && list_empty(&list))
1139                 return 0;
1140
1141         while (!list_empty(&list)) {
1142                 sums = list_entry(list.next, struct btrfs_ordered_sum, list);
1143                 list_del(&sums->list);
1144                 kfree(sums);
1145         }
1146         return 1;
1147 }
1148
1149 /*
1150  * when nowcow writeback call back.  This checks for snapshots or COW copies
1151  * of the extents that exist in the file, and COWs the file as required.
1152  *
1153  * If no cow copies or snapshots exist, we write directly to the existing
1154  * blocks on disk
1155  */
1156 static noinline int run_delalloc_nocow(struct inode *inode,
1157                                        struct page *locked_page,
1158                               u64 start, u64 end, int *page_started, int force,
1159                               unsigned long *nr_written)
1160 {
1161         struct btrfs_root *root = BTRFS_I(inode)->root;
1162         struct btrfs_trans_handle *trans;
1163         struct extent_buffer *leaf;
1164         struct btrfs_path *path;
1165         struct btrfs_file_extent_item *fi;
1166         struct btrfs_key found_key;
1167         u64 cow_start;
1168         u64 cur_offset;
1169         u64 extent_end;
1170         u64 extent_offset;
1171         u64 disk_bytenr;
1172         u64 num_bytes;
1173         u64 disk_num_bytes;
1174         u64 ram_bytes;
1175         int extent_type;
1176         int ret, err;
1177         int type;
1178         int nocow;
1179         int check_prev = 1;
1180         bool nolock;
1181         u64 ino = btrfs_ino(inode);
1182
1183         path = btrfs_alloc_path();
1184         if (!path) {
1185                 extent_clear_unlock_delalloc(inode, start, end, locked_page,
1186                                              EXTENT_LOCKED | EXTENT_DELALLOC |
1187                                              EXTENT_DO_ACCOUNTING |
1188                                              EXTENT_DEFRAG, PAGE_UNLOCK |
1189                                              PAGE_CLEAR_DIRTY |
1190                                              PAGE_SET_WRITEBACK |
1191                                              PAGE_END_WRITEBACK);
1192                 return -ENOMEM;
1193         }
1194
1195         nolock = btrfs_is_free_space_inode(inode);
1196
1197         if (nolock)
1198                 trans = btrfs_join_transaction_nolock(root);
1199         else
1200                 trans = btrfs_join_transaction(root);
1201
1202         if (IS_ERR(trans)) {
1203                 extent_clear_unlock_delalloc(inode, start, end, locked_page,
1204                                              EXTENT_LOCKED | EXTENT_DELALLOC |
1205                                              EXTENT_DO_ACCOUNTING |
1206                                              EXTENT_DEFRAG, PAGE_UNLOCK |
1207                                              PAGE_CLEAR_DIRTY |
1208                                              PAGE_SET_WRITEBACK |
1209                                              PAGE_END_WRITEBACK);
1210                 btrfs_free_path(path);
1211                 return PTR_ERR(trans);
1212         }
1213
1214         trans->block_rsv = &root->fs_info->delalloc_block_rsv;
1215
1216         cow_start = (u64)-1;
1217         cur_offset = start;
1218         while (1) {
1219                 ret = btrfs_lookup_file_extent(trans, root, path, ino,
1220                                                cur_offset, 0);
1221                 if (ret < 0)
1222                         goto error;
1223                 if (ret > 0 && path->slots[0] > 0 && check_prev) {
1224                         leaf = path->nodes[0];
1225                         btrfs_item_key_to_cpu(leaf, &found_key,
1226                                               path->slots[0] - 1);
1227                         if (found_key.objectid == ino &&
1228                             found_key.type == BTRFS_EXTENT_DATA_KEY)
1229                                 path->slots[0]--;
1230                 }
1231                 check_prev = 0;
1232 next_slot:
1233                 leaf = path->nodes[0];
1234                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
1235                         ret = btrfs_next_leaf(root, path);
1236                         if (ret < 0)
1237                                 goto error;
1238                         if (ret > 0)
1239                                 break;
1240                         leaf = path->nodes[0];
1241                 }
1242
1243                 nocow = 0;
1244                 disk_bytenr = 0;
1245                 num_bytes = 0;
1246                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
1247
1248                 if (found_key.objectid > ino ||
1249                     found_key.type > BTRFS_EXTENT_DATA_KEY ||
1250                     found_key.offset > end)
1251                         break;
1252
1253                 if (found_key.offset > cur_offset) {
1254                         extent_end = found_key.offset;
1255                         extent_type = 0;
1256                         goto out_check;
1257                 }
1258
1259                 fi = btrfs_item_ptr(leaf, path->slots[0],
1260                                     struct btrfs_file_extent_item);
1261                 extent_type = btrfs_file_extent_type(leaf, fi);
1262
1263                 ram_bytes = btrfs_file_extent_ram_bytes(leaf, fi);
1264                 if (extent_type == BTRFS_FILE_EXTENT_REG ||
1265                     extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
1266                         disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1267                         extent_offset = btrfs_file_extent_offset(leaf, fi);
1268                         extent_end = found_key.offset +
1269                                 btrfs_file_extent_num_bytes(leaf, fi);
1270                         disk_num_bytes =
1271                                 btrfs_file_extent_disk_num_bytes(leaf, fi);
1272                         if (extent_end <= start) {
1273                                 path->slots[0]++;
1274                                 goto next_slot;
1275                         }
1276                         if (disk_bytenr == 0)
1277                                 goto out_check;
1278                         if (btrfs_file_extent_compression(leaf, fi) ||
1279                             btrfs_file_extent_encryption(leaf, fi) ||
1280                             btrfs_file_extent_other_encoding(leaf, fi))
1281                                 goto out_check;
1282                         if (extent_type == BTRFS_FILE_EXTENT_REG && !force)
1283                                 goto out_check;
1284                         if (btrfs_extent_readonly(root, disk_bytenr))
1285                                 goto out_check;
1286                         if (btrfs_cross_ref_exist(trans, root, ino,
1287                                                   found_key.offset -
1288                                                   extent_offset, disk_bytenr))
1289                                 goto out_check;
1290                         disk_bytenr += extent_offset;
1291                         disk_bytenr += cur_offset - found_key.offset;
1292                         num_bytes = min(end + 1, extent_end) - cur_offset;
1293                         /*
1294                          * if there are pending snapshots for this root,
1295                          * we fall into common COW way.
1296                          */
1297                         if (!nolock) {
1298                                 err = btrfs_start_nocow_write(root);
1299                                 if (!err)
1300                                         goto out_check;
1301                         }
1302                         /*
1303                          * force cow if csum exists in the range.
1304                          * this ensure that csum for a given extent are
1305                          * either valid or do not exist.
1306                          */
1307                         if (csum_exist_in_range(root, disk_bytenr, num_bytes))
1308                                 goto out_check;
1309                         nocow = 1;
1310                 } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
1311                         extent_end = found_key.offset +
1312                                 btrfs_file_extent_inline_len(leaf,
1313                                                      path->slots[0], fi);
1314                         extent_end = ALIGN(extent_end, root->sectorsize);
1315                 } else {
1316                         BUG_ON(1);
1317                 }
1318 out_check:
1319                 if (extent_end <= start) {
1320                         path->slots[0]++;
1321                         if (!nolock && nocow)
1322                                 btrfs_end_nocow_write(root);
1323                         goto next_slot;
1324                 }
1325                 if (!nocow) {
1326                         if (cow_start == (u64)-1)
1327                                 cow_start = cur_offset;
1328                         cur_offset = extent_end;
1329                         if (cur_offset > end)
1330                                 break;
1331                         path->slots[0]++;
1332                         goto next_slot;
1333                 }
1334
1335                 btrfs_release_path(path);
1336                 if (cow_start != (u64)-1) {
1337                         ret = cow_file_range(inode, locked_page,
1338                                              cow_start, found_key.offset - 1,
1339                                              page_started, nr_written, 1);
1340                         if (ret) {
1341                                 if (!nolock && nocow)
1342                                         btrfs_end_nocow_write(root);
1343                                 goto error;
1344                         }
1345                         cow_start = (u64)-1;
1346                 }
1347
1348                 if (extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
1349                         struct extent_map *em;
1350                         struct extent_map_tree *em_tree;
1351                         em_tree = &BTRFS_I(inode)->extent_tree;
1352                         em = alloc_extent_map();
1353                         BUG_ON(!em); /* -ENOMEM */
1354                         em->start = cur_offset;
1355                         em->orig_start = found_key.offset - extent_offset;
1356                         em->len = num_bytes;
1357                         em->block_len = num_bytes;
1358                         em->block_start = disk_bytenr;
1359                         em->orig_block_len = disk_num_bytes;
1360                         em->ram_bytes = ram_bytes;
1361                         em->bdev = root->fs_info->fs_devices->latest_bdev;
1362                         em->mod_start = em->start;
1363                         em->mod_len = em->len;
1364                         set_bit(EXTENT_FLAG_PINNED, &em->flags);
1365                         set_bit(EXTENT_FLAG_FILLING, &em->flags);
1366                         em->generation = -1;
1367                         while (1) {
1368                                 write_lock(&em_tree->lock);
1369                                 ret = add_extent_mapping(em_tree, em, 1);
1370                                 write_unlock(&em_tree->lock);
1371                                 if (ret != -EEXIST) {
1372                                         free_extent_map(em);
1373                                         break;
1374                                 }
1375                                 btrfs_drop_extent_cache(inode, em->start,
1376                                                 em->start + em->len - 1, 0);
1377                         }
1378                         type = BTRFS_ORDERED_PREALLOC;
1379                 } else {
1380                         type = BTRFS_ORDERED_NOCOW;
1381                 }
1382
1383                 ret = btrfs_add_ordered_extent(inode, cur_offset, disk_bytenr,
1384                                                num_bytes, num_bytes, type);
1385                 BUG_ON(ret); /* -ENOMEM */
1386
1387                 if (root->root_key.objectid ==
1388                     BTRFS_DATA_RELOC_TREE_OBJECTID) {
1389                         ret = btrfs_reloc_clone_csums(inode, cur_offset,
1390                                                       num_bytes);
1391                         if (ret) {
1392                                 if (!nolock && nocow)
1393                                         btrfs_end_nocow_write(root);
1394                                 goto error;
1395                         }
1396                 }
1397
1398                 extent_clear_unlock_delalloc(inode, cur_offset,
1399                                              cur_offset + num_bytes - 1,
1400                                              locked_page, EXTENT_LOCKED |
1401                                              EXTENT_DELALLOC, PAGE_UNLOCK |
1402                                              PAGE_SET_PRIVATE2);
1403                 if (!nolock && nocow)
1404                         btrfs_end_nocow_write(root);
1405                 cur_offset = extent_end;
1406                 if (cur_offset > end)
1407                         break;
1408         }
1409         btrfs_release_path(path);
1410
1411         if (cur_offset <= end && cow_start == (u64)-1) {
1412                 cow_start = cur_offset;
1413                 cur_offset = end;
1414         }
1415
1416         if (cow_start != (u64)-1) {
1417                 ret = cow_file_range(inode, locked_page, cow_start, end,
1418                                      page_started, nr_written, 1);
1419                 if (ret)
1420                         goto error;
1421         }
1422
1423 error:
1424         err = btrfs_end_transaction(trans, root);
1425         if (!ret)
1426                 ret = err;
1427
1428         if (ret && cur_offset < end)
1429                 extent_clear_unlock_delalloc(inode, cur_offset, end,
1430                                              locked_page, EXTENT_LOCKED |
1431                                              EXTENT_DELALLOC | EXTENT_DEFRAG |
1432                                              EXTENT_DO_ACCOUNTING, PAGE_UNLOCK |
1433                                              PAGE_CLEAR_DIRTY |
1434                                              PAGE_SET_WRITEBACK |
1435                                              PAGE_END_WRITEBACK);
1436         btrfs_free_path(path);
1437         return ret;
1438 }
1439
1440 /*
1441  * extent_io.c call back to do delayed allocation processing
1442  */
1443 static int run_delalloc_range(struct inode *inode, struct page *locked_page,
1444                               u64 start, u64 end, int *page_started,
1445                               unsigned long *nr_written)
1446 {
1447         int ret;
1448         struct btrfs_root *root = BTRFS_I(inode)->root;
1449
1450         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW) {
1451                 ret = run_delalloc_nocow(inode, locked_page, start, end,
1452                                          page_started, 1, nr_written);
1453         } else if (BTRFS_I(inode)->flags & BTRFS_INODE_PREALLOC) {
1454                 ret = run_delalloc_nocow(inode, locked_page, start, end,
1455                                          page_started, 0, nr_written);
1456         } else if (!btrfs_test_opt(root, COMPRESS) &&
1457                    !(BTRFS_I(inode)->force_compress) &&
1458                    !(BTRFS_I(inode)->flags & BTRFS_INODE_COMPRESS)) {
1459                 ret = cow_file_range(inode, locked_page, start, end,
1460                                       page_started, nr_written, 1);
1461         } else {
1462                 set_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
1463                         &BTRFS_I(inode)->runtime_flags);
1464                 ret = cow_file_range_async(inode, locked_page, start, end,
1465                                            page_started, nr_written);
1466         }
1467         return ret;
1468 }
1469
1470 static void btrfs_split_extent_hook(struct inode *inode,
1471                                     struct extent_state *orig, u64 split)
1472 {
1473         /* not delalloc, ignore it */
1474         if (!(orig->state & EXTENT_DELALLOC))
1475                 return;
1476
1477         spin_lock(&BTRFS_I(inode)->lock);
1478         BTRFS_I(inode)->outstanding_extents++;
1479         spin_unlock(&BTRFS_I(inode)->lock);
1480 }
1481
1482 /*
1483  * extent_io.c merge_extent_hook, used to track merged delayed allocation
1484  * extents so we can keep track of new extents that are just merged onto old
1485  * extents, such as when we are doing sequential writes, so we can properly
1486  * account for the metadata space we'll need.
1487  */
1488 static void btrfs_merge_extent_hook(struct inode *inode,
1489                                     struct extent_state *new,
1490                                     struct extent_state *other)
1491 {
1492         /* not delalloc, ignore it */
1493         if (!(other->state & EXTENT_DELALLOC))
1494                 return;
1495
1496         spin_lock(&BTRFS_I(inode)->lock);
1497         BTRFS_I(inode)->outstanding_extents--;
1498         spin_unlock(&BTRFS_I(inode)->lock);
1499 }
1500
1501 static void btrfs_add_delalloc_inodes(struct btrfs_root *root,
1502                                       struct inode *inode)
1503 {
1504         spin_lock(&root->delalloc_lock);
1505         if (list_empty(&BTRFS_I(inode)->delalloc_inodes)) {
1506                 list_add_tail(&BTRFS_I(inode)->delalloc_inodes,
1507                               &root->delalloc_inodes);
1508                 set_bit(BTRFS_INODE_IN_DELALLOC_LIST,
1509                         &BTRFS_I(inode)->runtime_flags);
1510                 root->nr_delalloc_inodes++;
1511                 if (root->nr_delalloc_inodes == 1) {
1512                         spin_lock(&root->fs_info->delalloc_root_lock);
1513                         BUG_ON(!list_empty(&root->delalloc_root));
1514                         list_add_tail(&root->delalloc_root,
1515                                       &root->fs_info->delalloc_roots);
1516                         spin_unlock(&root->fs_info->delalloc_root_lock);
1517                 }
1518         }
1519         spin_unlock(&root->delalloc_lock);
1520 }
1521
1522 static void btrfs_del_delalloc_inode(struct btrfs_root *root,
1523                                      struct inode *inode)
1524 {
1525         spin_lock(&root->delalloc_lock);
1526         if (!list_empty(&BTRFS_I(inode)->delalloc_inodes)) {
1527                 list_del_init(&BTRFS_I(inode)->delalloc_inodes);
1528                 clear_bit(BTRFS_INODE_IN_DELALLOC_LIST,
1529                           &BTRFS_I(inode)->runtime_flags);
1530                 root->nr_delalloc_inodes--;
1531                 if (!root->nr_delalloc_inodes) {
1532                         spin_lock(&root->fs_info->delalloc_root_lock);
1533                         BUG_ON(list_empty(&root->delalloc_root));
1534                         list_del_init(&root->delalloc_root);
1535                         spin_unlock(&root->fs_info->delalloc_root_lock);
1536                 }
1537         }
1538         spin_unlock(&root->delalloc_lock);
1539 }
1540
1541 /*
1542  * extent_io.c set_bit_hook, used to track delayed allocation
1543  * bytes in this file, and to maintain the list of inodes that
1544  * have pending delalloc work to be done.
1545  */
1546 static void btrfs_set_bit_hook(struct inode *inode,
1547                                struct extent_state *state, unsigned long *bits)
1548 {
1549
1550         /*
1551          * set_bit and clear bit hooks normally require _irqsave/restore
1552          * but in this case, we are only testing for the DELALLOC
1553          * bit, which is only set or cleared with irqs on
1554          */
1555         if (!(state->state & EXTENT_DELALLOC) && (*bits & EXTENT_DELALLOC)) {
1556                 struct btrfs_root *root = BTRFS_I(inode)->root;
1557                 u64 len = state->end + 1 - state->start;
1558                 bool do_list = !btrfs_is_free_space_inode(inode);
1559
1560                 if (*bits & EXTENT_FIRST_DELALLOC) {
1561                         *bits &= ~EXTENT_FIRST_DELALLOC;
1562                 } else {
1563                         spin_lock(&BTRFS_I(inode)->lock);
1564                         BTRFS_I(inode)->outstanding_extents++;
1565                         spin_unlock(&BTRFS_I(inode)->lock);
1566                 }
1567
1568                 __percpu_counter_add(&root->fs_info->delalloc_bytes, len,
1569                                      root->fs_info->delalloc_batch);
1570                 spin_lock(&BTRFS_I(inode)->lock);
1571                 BTRFS_I(inode)->delalloc_bytes += len;
1572                 if (do_list && !test_bit(BTRFS_INODE_IN_DELALLOC_LIST,
1573                                          &BTRFS_I(inode)->runtime_flags))
1574                         btrfs_add_delalloc_inodes(root, inode);
1575                 spin_unlock(&BTRFS_I(inode)->lock);
1576         }
1577 }
1578
1579 /*
1580  * extent_io.c clear_bit_hook, see set_bit_hook for why
1581  */
1582 static void btrfs_clear_bit_hook(struct inode *inode,
1583                                  struct extent_state *state,
1584                                  unsigned long *bits)
1585 {
1586         /*
1587          * set_bit and clear bit hooks normally require _irqsave/restore
1588          * but in this case, we are only testing for the DELALLOC
1589          * bit, which is only set or cleared with irqs on
1590          */
1591         if ((state->state & EXTENT_DELALLOC) && (*bits & EXTENT_DELALLOC)) {
1592                 struct btrfs_root *root = BTRFS_I(inode)->root;
1593                 u64 len = state->end + 1 - state->start;
1594                 bool do_list = !btrfs_is_free_space_inode(inode);
1595
1596                 if (*bits & EXTENT_FIRST_DELALLOC) {
1597                         *bits &= ~EXTENT_FIRST_DELALLOC;
1598                 } else if (!(*bits & EXTENT_DO_ACCOUNTING)) {
1599                         spin_lock(&BTRFS_I(inode)->lock);
1600                         BTRFS_I(inode)->outstanding_extents--;
1601                         spin_unlock(&BTRFS_I(inode)->lock);
1602                 }
1603
1604                 /*
1605                  * We don't reserve metadata space for space cache inodes so we
1606                  * don't need to call dellalloc_release_metadata if there is an
1607                  * error.
1608                  */
1609                 if (*bits & EXTENT_DO_ACCOUNTING &&
1610                     root != root->fs_info->tree_root)
1611                         btrfs_delalloc_release_metadata(inode, len);
1612
1613                 if (root->root_key.objectid != BTRFS_DATA_RELOC_TREE_OBJECTID
1614                     && do_list && !(state->state & EXTENT_NORESERVE))
1615                         btrfs_free_reserved_data_space(inode, len);
1616
1617                 __percpu_counter_add(&root->fs_info->delalloc_bytes, -len,
1618                                      root->fs_info->delalloc_batch);
1619                 spin_lock(&BTRFS_I(inode)->lock);
1620                 BTRFS_I(inode)->delalloc_bytes -= len;
1621                 if (do_list && BTRFS_I(inode)->delalloc_bytes == 0 &&
1622                     test_bit(BTRFS_INODE_IN_DELALLOC_LIST,
1623                              &BTRFS_I(inode)->runtime_flags))
1624                         btrfs_del_delalloc_inode(root, inode);
1625                 spin_unlock(&BTRFS_I(inode)->lock);
1626         }
1627 }
1628
1629 /*
1630  * extent_io.c merge_bio_hook, this must check the chunk tree to make sure
1631  * we don't create bios that span stripes or chunks
1632  */
1633 int btrfs_merge_bio_hook(int rw, struct page *page, unsigned long offset,
1634                          size_t size, struct bio *bio,
1635                          unsigned long bio_flags)
1636 {
1637         struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
1638         u64 logical = (u64)bio->bi_iter.bi_sector << 9;
1639         u64 length = 0;
1640         u64 map_length;
1641         int ret;
1642
1643         if (bio_flags & EXTENT_BIO_COMPRESSED)
1644                 return 0;
1645
1646         length = bio->bi_iter.bi_size;
1647         map_length = length;
1648         ret = btrfs_map_block(root->fs_info, rw, logical,
1649                               &map_length, NULL, 0);
1650         /* Will always return 0 with map_multi == NULL */
1651         BUG_ON(ret < 0);
1652         if (map_length < length + size)
1653                 return 1;
1654         return 0;
1655 }
1656
1657 /*
1658  * in order to insert checksums into the metadata in large chunks,
1659  * we wait until bio submission time.   All the pages in the bio are
1660  * checksummed and sums are attached onto the ordered extent record.
1661  *
1662  * At IO completion time the cums attached on the ordered extent record
1663  * are inserted into the btree
1664  */
1665 static int __btrfs_submit_bio_start(struct inode *inode, int rw,
1666                                     struct bio *bio, int mirror_num,
1667                                     unsigned long bio_flags,
1668                                     u64 bio_offset)
1669 {
1670         struct btrfs_root *root = BTRFS_I(inode)->root;
1671         int ret = 0;
1672
1673         ret = btrfs_csum_one_bio(root, inode, bio, 0, 0);
1674         BUG_ON(ret); /* -ENOMEM */
1675         return 0;
1676 }
1677
1678 /*
1679  * in order to insert checksums into the metadata in large chunks,
1680  * we wait until bio submission time.   All the pages in the bio are
1681  * checksummed and sums are attached onto the ordered extent record.
1682  *
1683  * At IO completion time the cums attached on the ordered extent record
1684  * are inserted into the btree
1685  */
1686 static int __btrfs_submit_bio_done(struct inode *inode, int rw, struct bio *bio,
1687                           int mirror_num, unsigned long bio_flags,
1688                           u64 bio_offset)
1689 {
1690         struct btrfs_root *root = BTRFS_I(inode)->root;
1691         int ret;
1692
1693         ret = btrfs_map_bio(root, rw, bio, mirror_num, 1);
1694         if (ret)
1695                 bio_endio(bio, ret);
1696         return ret;
1697 }
1698
1699 /*
1700  * extent_io.c submission hook. This does the right thing for csum calculation
1701  * on write, or reading the csums from the tree before a read
1702  */
1703 static int btrfs_submit_bio_hook(struct inode *inode, int rw, struct bio *bio,
1704                           int mirror_num, unsigned long bio_flags,
1705                           u64 bio_offset)
1706 {
1707         struct btrfs_root *root = BTRFS_I(inode)->root;
1708         int ret = 0;
1709         int skip_sum;
1710         int metadata = 0;
1711         int async = !atomic_read(&BTRFS_I(inode)->sync_writers);
1712
1713         skip_sum = BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM;
1714
1715         if (btrfs_is_free_space_inode(inode))
1716                 metadata = 2;
1717
1718         if (!(rw & REQ_WRITE)) {
1719                 ret = btrfs_bio_wq_end_io(root->fs_info, bio, metadata);
1720                 if (ret)
1721                         goto out;
1722
1723                 if (bio_flags & EXTENT_BIO_COMPRESSED) {
1724                         ret = btrfs_submit_compressed_read(inode, bio,
1725                                                            mirror_num,
1726                                                            bio_flags);
1727                         goto out;
1728                 } else if (!skip_sum) {
1729                         ret = btrfs_lookup_bio_sums(root, inode, bio, NULL);
1730                         if (ret)
1731                                 goto out;
1732                 }
1733                 goto mapit;
1734         } else if (async && !skip_sum) {
1735                 /* csum items have already been cloned */
1736                 if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID)
1737                         goto mapit;
1738                 /* we're doing a write, do the async checksumming */
1739                 ret = btrfs_wq_submit_bio(BTRFS_I(inode)->root->fs_info,
1740                                    inode, rw, bio, mirror_num,
1741                                    bio_flags, bio_offset,
1742                                    __btrfs_submit_bio_start,
1743                                    __btrfs_submit_bio_done);
1744                 goto out;
1745         } else if (!skip_sum) {
1746                 ret = btrfs_csum_one_bio(root, inode, bio, 0, 0);
1747                 if (ret)
1748                         goto out;
1749         }
1750
1751 mapit:
1752         ret = btrfs_map_bio(root, rw, bio, mirror_num, 0);
1753
1754 out:
1755         if (ret < 0)
1756                 bio_endio(bio, ret);
1757         return ret;
1758 }
1759
1760 /*
1761  * given a list of ordered sums record them in the inode.  This happens
1762  * at IO completion time based on sums calculated at bio submission time.
1763  */
1764 static noinline int add_pending_csums(struct btrfs_trans_handle *trans,
1765                              struct inode *inode, u64 file_offset,
1766                              struct list_head *list)
1767 {
1768         struct btrfs_ordered_sum *sum;
1769
1770         list_for_each_entry(sum, list, list) {
1771                 trans->adding_csums = 1;
1772                 btrfs_csum_file_blocks(trans,
1773                        BTRFS_I(inode)->root->fs_info->csum_root, sum);
1774                 trans->adding_csums = 0;
1775         }
1776         return 0;
1777 }
1778
1779 int btrfs_set_extent_delalloc(struct inode *inode, u64 start, u64 end,
1780                               struct extent_state **cached_state)
1781 {
1782         WARN_ON((end & (PAGE_CACHE_SIZE - 1)) == 0);
1783         return set_extent_delalloc(&BTRFS_I(inode)->io_tree, start, end,
1784                                    cached_state, GFP_NOFS);
1785 }
1786
1787 /* see btrfs_writepage_start_hook for details on why this is required */
1788 struct btrfs_writepage_fixup {
1789         struct page *page;
1790         struct btrfs_work work;
1791 };
1792
1793 static void btrfs_writepage_fixup_worker(struct btrfs_work *work)
1794 {
1795         struct btrfs_writepage_fixup *fixup;
1796         struct btrfs_ordered_extent *ordered;
1797         struct extent_state *cached_state = NULL;
1798         struct page *page;
1799         struct inode *inode;
1800         u64 page_start;
1801         u64 page_end;
1802         int ret;
1803
1804         fixup = container_of(work, struct btrfs_writepage_fixup, work);
1805         page = fixup->page;
1806 again:
1807         lock_page(page);
1808         if (!page->mapping || !PageDirty(page) || !PageChecked(page)) {
1809                 ClearPageChecked(page);
1810                 goto out_page;
1811         }
1812
1813         inode = page->mapping->host;
1814         page_start = page_offset(page);
1815         page_end = page_offset(page) + PAGE_CACHE_SIZE - 1;
1816
1817         lock_extent_bits(&BTRFS_I(inode)->io_tree, page_start, page_end, 0,
1818                          &cached_state);
1819
1820         /* already ordered? We're done */
1821         if (PagePrivate2(page))
1822                 goto out;
1823
1824         ordered = btrfs_lookup_ordered_extent(inode, page_start);
1825         if (ordered) {
1826                 unlock_extent_cached(&BTRFS_I(inode)->io_tree, page_start,
1827                                      page_end, &cached_state, GFP_NOFS);
1828                 unlock_page(page);
1829                 btrfs_start_ordered_extent(inode, ordered, 1);
1830                 btrfs_put_ordered_extent(ordered);
1831                 goto again;
1832         }
1833
1834         ret = btrfs_delalloc_reserve_space(inode, PAGE_CACHE_SIZE);
1835         if (ret) {
1836                 mapping_set_error(page->mapping, ret);
1837                 end_extent_writepage(page, ret, page_start, page_end);
1838                 ClearPageChecked(page);
1839                 goto out;
1840          }
1841
1842         btrfs_set_extent_delalloc(inode, page_start, page_end, &cached_state);
1843         ClearPageChecked(page);
1844         set_page_dirty(page);
1845 out:
1846         unlock_extent_cached(&BTRFS_I(inode)->io_tree, page_start, page_end,
1847                              &cached_state, GFP_NOFS);
1848 out_page:
1849         unlock_page(page);
1850         page_cache_release(page);
1851         kfree(fixup);
1852 }
1853
1854 /*
1855  * There are a few paths in the higher layers of the kernel that directly
1856  * set the page dirty bit without asking the filesystem if it is a
1857  * good idea.  This causes problems because we want to make sure COW
1858  * properly happens and the data=ordered rules are followed.
1859  *
1860  * In our case any range that doesn't have the ORDERED bit set
1861  * hasn't been properly setup for IO.  We kick off an async process
1862  * to fix it up.  The async helper will wait for ordered extents, set
1863  * the delalloc bit and make it safe to write the page.
1864  */
1865 static int btrfs_writepage_start_hook(struct page *page, u64 start, u64 end)
1866 {
1867         struct inode *inode = page->mapping->host;
1868         struct btrfs_writepage_fixup *fixup;
1869         struct btrfs_root *root = BTRFS_I(inode)->root;
1870
1871         /* this page is properly in the ordered list */
1872         if (TestClearPagePrivate2(page))
1873                 return 0;
1874
1875         if (PageChecked(page))
1876                 return -EAGAIN;
1877
1878         fixup = kzalloc(sizeof(*fixup), GFP_NOFS);
1879         if (!fixup)
1880                 return -EAGAIN;
1881
1882         SetPageChecked(page);
1883         page_cache_get(page);
1884         btrfs_init_work(&fixup->work, btrfs_writepage_fixup_worker, NULL, NULL);
1885         fixup->page = page;
1886         btrfs_queue_work(root->fs_info->fixup_workers, &fixup->work);
1887         return -EBUSY;
1888 }
1889
1890 static int insert_reserved_file_extent(struct btrfs_trans_handle *trans,
1891                                        struct inode *inode, u64 file_pos,
1892                                        u64 disk_bytenr, u64 disk_num_bytes,
1893                                        u64 num_bytes, u64 ram_bytes,
1894                                        u8 compression, u8 encryption,
1895                                        u16 other_encoding, int extent_type)
1896 {
1897         struct btrfs_root *root = BTRFS_I(inode)->root;
1898         struct btrfs_file_extent_item *fi;
1899         struct btrfs_path *path;
1900         struct extent_buffer *leaf;
1901         struct btrfs_key ins;
1902         int extent_inserted = 0;
1903         int ret;
1904
1905         path = btrfs_alloc_path();
1906         if (!path)
1907                 return -ENOMEM;
1908
1909         /*
1910          * we may be replacing one extent in the tree with another.
1911          * The new extent is pinned in the extent map, and we don't want
1912          * to drop it from the cache until it is completely in the btree.
1913          *
1914          * So, tell btrfs_drop_extents to leave this extent in the cache.
1915          * the caller is expected to unpin it and allow it to be merged
1916          * with the others.
1917          */
1918         ret = __btrfs_drop_extents(trans, root, inode, path, file_pos,
1919                                    file_pos + num_bytes, NULL, 0,
1920                                    1, sizeof(*fi), &extent_inserted);
1921         if (ret)
1922                 goto out;
1923
1924         if (!extent_inserted) {
1925                 ins.objectid = btrfs_ino(inode);
1926                 ins.offset = file_pos;
1927                 ins.type = BTRFS_EXTENT_DATA_KEY;
1928
1929                 path->leave_spinning = 1;
1930                 ret = btrfs_insert_empty_item(trans, root, path, &ins,
1931                                               sizeof(*fi));
1932                 if (ret)
1933                         goto out;
1934         }
1935         leaf = path->nodes[0];
1936         fi = btrfs_item_ptr(leaf, path->slots[0],
1937                             struct btrfs_file_extent_item);
1938         btrfs_set_file_extent_generation(leaf, fi, trans->transid);
1939         btrfs_set_file_extent_type(leaf, fi, extent_type);
1940         btrfs_set_file_extent_disk_bytenr(leaf, fi, disk_bytenr);
1941         btrfs_set_file_extent_disk_num_bytes(leaf, fi, disk_num_bytes);
1942         btrfs_set_file_extent_offset(leaf, fi, 0);
1943         btrfs_set_file_extent_num_bytes(leaf, fi, num_bytes);
1944         btrfs_set_file_extent_ram_bytes(leaf, fi, ram_bytes);
1945         btrfs_set_file_extent_compression(leaf, fi, compression);
1946         btrfs_set_file_extent_encryption(leaf, fi, encryption);
1947         btrfs_set_file_extent_other_encoding(leaf, fi, other_encoding);
1948
1949         btrfs_mark_buffer_dirty(leaf);
1950         btrfs_release_path(path);
1951
1952         inode_add_bytes(inode, num_bytes);
1953
1954         ins.objectid = disk_bytenr;
1955         ins.offset = disk_num_bytes;
1956         ins.type = BTRFS_EXTENT_ITEM_KEY;
1957         ret = btrfs_alloc_reserved_file_extent(trans, root,
1958                                         root->root_key.objectid,
1959                                         btrfs_ino(inode), file_pos, &ins);
1960 out:
1961         btrfs_free_path(path);
1962
1963         return ret;
1964 }
1965
1966 /* snapshot-aware defrag */
1967 struct sa_defrag_extent_backref {
1968         struct rb_node node;
1969         struct old_sa_defrag_extent *old;
1970         u64 root_id;
1971         u64 inum;
1972         u64 file_pos;
1973         u64 extent_offset;
1974         u64 num_bytes;
1975         u64 generation;
1976 };
1977
1978 struct old_sa_defrag_extent {
1979         struct list_head list;
1980         struct new_sa_defrag_extent *new;
1981
1982         u64 extent_offset;
1983         u64 bytenr;
1984         u64 offset;
1985         u64 len;
1986         int count;
1987 };
1988
1989 struct new_sa_defrag_extent {
1990         struct rb_root root;
1991         struct list_head head;
1992         struct btrfs_path *path;
1993         struct inode *inode;
1994         u64 file_pos;
1995         u64 len;
1996         u64 bytenr;
1997         u64 disk_len;
1998         u8 compress_type;
1999 };
2000
2001 static int backref_comp(struct sa_defrag_extent_backref *b1,
2002                         struct sa_defrag_extent_backref *b2)
2003 {
2004         if (b1->root_id < b2->root_id)
2005                 return -1;
2006         else if (b1->root_id > b2->root_id)
2007                 return 1;
2008
2009         if (b1->inum < b2->inum)
2010                 return -1;
2011         else if (b1->inum > b2->inum)
2012                 return 1;
2013
2014         if (b1->file_pos < b2->file_pos)
2015                 return -1;
2016         else if (b1->file_pos > b2->file_pos)
2017                 return 1;
2018
2019         /*
2020          * [------------------------------] ===> (a range of space)
2021          *     |<--->|   |<---->| =============> (fs/file tree A)
2022          * |<---------------------------->| ===> (fs/file tree B)
2023          *
2024          * A range of space can refer to two file extents in one tree while
2025          * refer to only one file extent in another tree.
2026          *
2027          * So we may process a disk offset more than one time(two extents in A)
2028          * and locate at the same extent(one extent in B), then insert two same
2029          * backrefs(both refer to the extent in B).
2030          */
2031         return 0;
2032 }
2033
2034 static void backref_insert(struct rb_root *root,
2035                            struct sa_defrag_extent_backref *backref)
2036 {
2037         struct rb_node **p = &root->rb_node;
2038         struct rb_node *parent = NULL;
2039         struct sa_defrag_extent_backref *entry;
2040         int ret;
2041
2042         while (*p) {
2043                 parent = *p;
2044                 entry = rb_entry(parent, struct sa_defrag_extent_backref, node);
2045
2046                 ret = backref_comp(backref, entry);
2047                 if (ret < 0)
2048                         p = &(*p)->rb_left;
2049                 else
2050                         p = &(*p)->rb_right;
2051         }
2052
2053         rb_link_node(&backref->node, parent, p);
2054         rb_insert_color(&backref->node, root);
2055 }
2056
2057 /*
2058  * Note the backref might has changed, and in this case we just return 0.
2059  */
2060 static noinline int record_one_backref(u64 inum, u64 offset, u64 root_id,
2061                                        void *ctx)
2062 {
2063         struct btrfs_file_extent_item *extent;
2064         struct btrfs_fs_info *fs_info;
2065         struct old_sa_defrag_extent *old = ctx;
2066         struct new_sa_defrag_extent *new = old->new;
2067         struct btrfs_path *path = new->path;
2068         struct btrfs_key key;
2069         struct btrfs_root *root;
2070         struct sa_defrag_extent_backref *backref;
2071         struct extent_buffer *leaf;
2072         struct inode *inode = new->inode;
2073         int slot;
2074         int ret;
2075         u64 extent_offset;
2076         u64 num_bytes;
2077
2078         if (BTRFS_I(inode)->root->root_key.objectid == root_id &&
2079             inum == btrfs_ino(inode))
2080                 return 0;
2081
2082         key.objectid = root_id;
2083         key.type = BTRFS_ROOT_ITEM_KEY;
2084         key.offset = (u64)-1;
2085
2086         fs_info = BTRFS_I(inode)->root->fs_info;
2087         root = btrfs_read_fs_root_no_name(fs_info, &key);
2088         if (IS_ERR(root)) {
2089                 if (PTR_ERR(root) == -ENOENT)
2090                         return 0;
2091                 WARN_ON(1);
2092                 pr_debug("inum=%llu, offset=%llu, root_id=%llu\n",
2093                          inum, offset, root_id);
2094                 return PTR_ERR(root);
2095         }
2096
2097         key.objectid = inum;
2098         key.type = BTRFS_EXTENT_DATA_KEY;
2099         if (offset > (u64)-1 << 32)
2100                 key.offset = 0;
2101         else
2102                 key.offset = offset;
2103
2104         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2105         if (WARN_ON(ret < 0))
2106                 return ret;
2107         ret = 0;
2108
2109         while (1) {
2110                 cond_resched();
2111
2112                 leaf = path->nodes[0];
2113                 slot = path->slots[0];
2114
2115                 if (slot >= btrfs_header_nritems(leaf)) {
2116                         ret = btrfs_next_leaf(root, path);
2117                         if (ret < 0) {
2118                                 goto out;
2119                         } else if (ret > 0) {
2120                                 ret = 0;
2121                                 goto out;
2122                         }
2123                         continue;
2124                 }
2125
2126                 path->slots[0]++;
2127
2128                 btrfs_item_key_to_cpu(leaf, &key, slot);
2129
2130                 if (key.objectid > inum)
2131                         goto out;
2132
2133                 if (key.objectid < inum || key.type != BTRFS_EXTENT_DATA_KEY)
2134                         continue;
2135
2136                 extent = btrfs_item_ptr(leaf, slot,
2137                                         struct btrfs_file_extent_item);
2138
2139                 if (btrfs_file_extent_disk_bytenr(leaf, extent) != old->bytenr)
2140                         continue;
2141
2142                 /*
2143                  * 'offset' refers to the exact key.offset,
2144                  * NOT the 'offset' field in btrfs_extent_data_ref, ie.
2145                  * (key.offset - extent_offset).
2146                  */
2147                 if (key.offset != offset)
2148                         continue;
2149
2150                 extent_offset = btrfs_file_extent_offset(leaf, extent);
2151                 num_bytes = btrfs_file_extent_num_bytes(leaf, extent);
2152
2153                 if (extent_offset >= old->extent_offset + old->offset +
2154                     old->len || extent_offset + num_bytes <=
2155                     old->extent_offset + old->offset)
2156                         continue;
2157                 break;
2158         }
2159
2160         backref = kmalloc(sizeof(*backref), GFP_NOFS);
2161         if (!backref) {
2162                 ret = -ENOENT;
2163                 goto out;
2164         }
2165
2166         backref->root_id = root_id;
2167         backref->inum = inum;
2168         backref->file_pos = offset;
2169         backref->num_bytes = num_bytes;
2170         backref->extent_offset = extent_offset;
2171         backref->generation = btrfs_file_extent_generation(leaf, extent);
2172         backref->old = old;
2173         backref_insert(&new->root, backref);
2174         old->count++;
2175 out:
2176         btrfs_release_path(path);
2177         WARN_ON(ret);
2178         return ret;
2179 }
2180
2181 static noinline bool record_extent_backrefs(struct btrfs_path *path,
2182                                    struct new_sa_defrag_extent *new)
2183 {
2184         struct btrfs_fs_info *fs_info = BTRFS_I(new->inode)->root->fs_info;
2185         struct old_sa_defrag_extent *old, *tmp;
2186         int ret;
2187
2188         new->path = path;
2189
2190         list_for_each_entry_safe(old, tmp, &new->head, list) {
2191                 ret = iterate_inodes_from_logical(old->bytenr +
2192                                                   old->extent_offset, fs_info,
2193                                                   path, record_one_backref,
2194                                                   old);
2195                 if (ret < 0 && ret != -ENOENT)
2196                         return false;
2197
2198                 /* no backref to be processed for this extent */
2199                 if (!old->count) {
2200                         list_del(&old->list);
2201                         kfree(old);
2202                 }
2203         }
2204
2205         if (list_empty(&new->head))
2206                 return false;
2207
2208         return true;
2209 }
2210
2211 static int relink_is_mergable(struct extent_buffer *leaf,
2212                               struct btrfs_file_extent_item *fi,
2213                               struct new_sa_defrag_extent *new)
2214 {
2215         if (btrfs_file_extent_disk_bytenr(leaf, fi) != new->bytenr)
2216                 return 0;
2217
2218         if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG)
2219                 return 0;
2220
2221         if (btrfs_file_extent_compression(leaf, fi) != new->compress_type)
2222                 return 0;
2223
2224         if (btrfs_file_extent_encryption(leaf, fi) ||
2225             btrfs_file_extent_other_encoding(leaf, fi))
2226                 return 0;
2227
2228         return 1;
2229 }
2230
2231 /*
2232  * Note the backref might has changed, and in this case we just return 0.
2233  */
2234 static noinline int relink_extent_backref(struct btrfs_path *path,
2235                                  struct sa_defrag_extent_backref *prev,
2236                                  struct sa_defrag_extent_backref *backref)
2237 {
2238         struct btrfs_file_extent_item *extent;
2239         struct btrfs_file_extent_item *item;
2240         struct btrfs_ordered_extent *ordered;
2241         struct btrfs_trans_handle *trans;
2242         struct btrfs_fs_info *fs_info;
2243         struct btrfs_root *root;
2244         struct btrfs_key key;
2245         struct extent_buffer *leaf;
2246         struct old_sa_defrag_extent *old = backref->old;
2247         struct new_sa_defrag_extent *new = old->new;
2248         struct inode *src_inode = new->inode;
2249         struct inode *inode;
2250         struct extent_state *cached = NULL;
2251         int ret = 0;
2252         u64 start;
2253         u64 len;
2254         u64 lock_start;
2255         u64 lock_end;
2256         bool merge = false;
2257         int index;
2258
2259         if (prev && prev->root_id == backref->root_id &&
2260             prev->inum == backref->inum &&
2261             prev->file_pos + prev->num_bytes == backref->file_pos)
2262                 merge = true;
2263
2264         /* step 1: get root */
2265         key.objectid = backref->root_id;
2266         key.type = BTRFS_ROOT_ITEM_KEY;
2267         key.offset = (u64)-1;
2268
2269         fs_info = BTRFS_I(src_inode)->root->fs_info;
2270         index = srcu_read_lock(&fs_info->subvol_srcu);
2271
2272         root = btrfs_read_fs_root_no_name(fs_info, &key);
2273         if (IS_ERR(root)) {
2274                 srcu_read_unlock(&fs_info->subvol_srcu, index);
2275                 if (PTR_ERR(root) == -ENOENT)
2276                         return 0;
2277                 return PTR_ERR(root);
2278         }
2279
2280         if (btrfs_root_readonly(root)) {
2281                 srcu_read_unlock(&fs_info->subvol_srcu, index);
2282                 return 0;
2283         }
2284
2285         /* step 2: get inode */
2286         key.objectid = backref->inum;
2287         key.type = BTRFS_INODE_ITEM_KEY;
2288         key.offset = 0;
2289
2290         inode = btrfs_iget(fs_info->sb, &key, root, NULL);
2291         if (IS_ERR(inode)) {
2292                 srcu_read_unlock(&fs_info->subvol_srcu, index);
2293                 return 0;
2294         }
2295
2296         srcu_read_unlock(&fs_info->subvol_srcu, index);
2297
2298         /* step 3: relink backref */
2299         lock_start = backref->file_pos;
2300         lock_end = backref->file_pos + backref->num_bytes - 1;
2301         lock_extent_bits(&BTRFS_I(inode)->io_tree, lock_start, lock_end,
2302                          0, &cached);
2303
2304         ordered = btrfs_lookup_first_ordered_extent(inode, lock_end);
2305         if (ordered) {
2306                 btrfs_put_ordered_extent(ordered);
2307                 goto out_unlock;
2308         }
2309
2310         trans = btrfs_join_transaction(root);
2311         if (IS_ERR(trans)) {
2312                 ret = PTR_ERR(trans);
2313                 goto out_unlock;
2314         }
2315
2316         key.objectid = backref->inum;
2317         key.type = BTRFS_EXTENT_DATA_KEY;
2318         key.offset = backref->file_pos;
2319
2320         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2321         if (ret < 0) {
2322                 goto out_free_path;
2323         } else if (ret > 0) {
2324                 ret = 0;
2325                 goto out_free_path;
2326         }
2327
2328         extent = btrfs_item_ptr(path->nodes[0], path->slots[0],
2329                                 struct btrfs_file_extent_item);
2330
2331         if (btrfs_file_extent_generation(path->nodes[0], extent) !=
2332             backref->generation)
2333                 goto out_free_path;
2334
2335         btrfs_release_path(path);
2336
2337         start = backref->file_pos;
2338         if (backref->extent_offset < old->extent_offset + old->offset)
2339                 start += old->extent_offset + old->offset -
2340                          backref->extent_offset;
2341
2342         len = min(backref->extent_offset + backref->num_bytes,
2343                   old->extent_offset + old->offset + old->len);
2344         len -= max(backref->extent_offset, old->extent_offset + old->offset);
2345
2346         ret = btrfs_drop_extents(trans, root, inode, start,
2347                                  start + len, 1);
2348         if (ret)
2349                 goto out_free_path;
2350 again:
2351         key.objectid = btrfs_ino(inode);
2352         key.type = BTRFS_EXTENT_DATA_KEY;
2353         key.offset = start;
2354
2355         path->leave_spinning = 1;
2356         if (merge) {
2357                 struct btrfs_file_extent_item *fi;
2358                 u64 extent_len;
2359                 struct btrfs_key found_key;
2360
2361                 ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
2362                 if (ret < 0)
2363                         goto out_free_path;
2364
2365                 path->slots[0]--;
2366                 leaf = path->nodes[0];
2367                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2368
2369                 fi = btrfs_item_ptr(leaf, path->slots[0],
2370                                     struct btrfs_file_extent_item);
2371                 extent_len = btrfs_file_extent_num_bytes(leaf, fi);
2372
2373                 if (extent_len + found_key.offset == start &&
2374                     relink_is_mergable(leaf, fi, new)) {
2375                         btrfs_set_file_extent_num_bytes(leaf, fi,
2376                                                         extent_len + len);
2377                         btrfs_mark_buffer_dirty(leaf);
2378                         inode_add_bytes(inode, len);
2379
2380                         ret = 1;
2381                         goto out_free_path;
2382                 } else {
2383                         merge = false;
2384                         btrfs_release_path(path);
2385                         goto again;
2386                 }
2387         }
2388
2389         ret = btrfs_insert_empty_item(trans, root, path, &key,
2390                                         sizeof(*extent));
2391         if (ret) {
2392                 btrfs_abort_transaction(trans, root, ret);
2393                 goto out_free_path;
2394         }
2395
2396         leaf = path->nodes[0];
2397         item = btrfs_item_ptr(leaf, path->slots[0],
2398                                 struct btrfs_file_extent_item);
2399         btrfs_set_file_extent_disk_bytenr(leaf, item, new->bytenr);
2400         btrfs_set_file_extent_disk_num_bytes(leaf, item, new->disk_len);
2401         btrfs_set_file_extent_offset(leaf, item, start - new->file_pos);
2402         btrfs_set_file_extent_num_bytes(leaf, item, len);
2403         btrfs_set_file_extent_ram_bytes(leaf, item, new->len);
2404         btrfs_set_file_extent_generation(leaf, item, trans->transid);
2405         btrfs_set_file_extent_type(leaf, item, BTRFS_FILE_EXTENT_REG);
2406         btrfs_set_file_extent_compression(leaf, item, new->compress_type);
2407         btrfs_set_file_extent_encryption(leaf, item, 0);
2408         btrfs_set_file_extent_other_encoding(leaf, item, 0);
2409
2410         btrfs_mark_buffer_dirty(leaf);
2411         inode_add_bytes(inode, len);
2412         btrfs_release_path(path);
2413
2414         ret = btrfs_inc_extent_ref(trans, root, new->bytenr,
2415                         new->disk_len, 0,
2416                         backref->root_id, backref->inum,
2417                         new->file_pos, 0);      /* start - extent_offset */
2418         if (ret) {
2419                 btrfs_abort_transaction(trans, root, ret);
2420                 goto out_free_path;
2421         }
2422
2423         ret = 1;
2424 out_free_path:
2425         btrfs_release_path(path);
2426         path->leave_spinning = 0;
2427         btrfs_end_transaction(trans, root);
2428 out_unlock:
2429         unlock_extent_cached(&BTRFS_I(inode)->io_tree, lock_start, lock_end,
2430                              &cached, GFP_NOFS);
2431         iput(inode);
2432         return ret;
2433 }
2434
2435 static void free_sa_defrag_extent(struct new_sa_defrag_extent *new)
2436 {
2437         struct old_sa_defrag_extent *old, *tmp;
2438
2439         if (!new)
2440                 return;
2441
2442         list_for_each_entry_safe(old, tmp, &new->head, list) {
2443                 list_del(&old->list);
2444                 kfree(old);
2445         }
2446         kfree(new);
2447 }
2448
2449 static void relink_file_extents(struct new_sa_defrag_extent *new)
2450 {
2451         struct btrfs_path *path;
2452         struct sa_defrag_extent_backref *backref;
2453         struct sa_defrag_extent_backref *prev = NULL;
2454         struct inode *inode;
2455         struct btrfs_root *root;
2456         struct rb_node *node;
2457         int ret;
2458
2459         inode = new->inode;
2460         root = BTRFS_I(inode)->root;
2461
2462         path = btrfs_alloc_path();
2463         if (!path)
2464                 return;
2465
2466         if (!record_extent_backrefs(path, new)) {
2467                 btrfs_free_path(path);
2468                 goto out;
2469         }
2470         btrfs_release_path(path);
2471
2472         while (1) {
2473                 node = rb_first(&new->root);
2474                 if (!node)
2475                         break;
2476                 rb_erase(node, &new->root);
2477
2478                 backref = rb_entry(node, struct sa_defrag_extent_backref, node);
2479
2480                 ret = relink_extent_backref(path, prev, backref);
2481                 WARN_ON(ret < 0);
2482
2483                 kfree(prev);
2484
2485                 if (ret == 1)
2486                         prev = backref;
2487                 else
2488                         prev = NULL;
2489                 cond_resched();
2490         }
2491         kfree(prev);
2492
2493         btrfs_free_path(path);
2494 out:
2495         free_sa_defrag_extent(new);
2496
2497         atomic_dec(&root->fs_info->defrag_running);
2498         wake_up(&root->fs_info->transaction_wait);
2499 }
2500
2501 static struct new_sa_defrag_extent *
2502 record_old_file_extents(struct inode *inode,
2503                         struct btrfs_ordered_extent *ordered)
2504 {
2505         struct btrfs_root *root = BTRFS_I(inode)->root;
2506         struct btrfs_path *path;
2507         struct btrfs_key key;
2508         struct old_sa_defrag_extent *old;
2509         struct new_sa_defrag_extent *new;
2510         int ret;
2511
2512         new = kmalloc(sizeof(*new), GFP_NOFS);
2513         if (!new)
2514                 return NULL;
2515
2516         new->inode = inode;
2517         new->file_pos = ordered->file_offset;
2518         new->len = ordered->len;
2519         new->bytenr = ordered->start;
2520         new->disk_len = ordered->disk_len;
2521         new->compress_type = ordered->compress_type;
2522         new->root = RB_ROOT;
2523         INIT_LIST_HEAD(&new->head);
2524
2525         path = btrfs_alloc_path();
2526         if (!path)
2527                 goto out_kfree;
2528
2529         key.objectid = btrfs_ino(inode);
2530         key.type = BTRFS_EXTENT_DATA_KEY;
2531         key.offset = new->file_pos;
2532
2533         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2534         if (ret < 0)
2535                 goto out_free_path;
2536         if (ret > 0 && path->slots[0] > 0)
2537                 path->slots[0]--;
2538
2539         /* find out all the old extents for the file range */
2540         while (1) {
2541                 struct btrfs_file_extent_item *extent;
2542                 struct extent_buffer *l;
2543                 int slot;
2544                 u64 num_bytes;
2545                 u64 offset;
2546                 u64 end;
2547                 u64 disk_bytenr;
2548                 u64 extent_offset;
2549
2550                 l = path->nodes[0];
2551                 slot = path->slots[0];
2552
2553                 if (slot >= btrfs_header_nritems(l)) {
2554                         ret = btrfs_next_leaf(root, path);
2555                         if (ret < 0)
2556                                 goto out_free_path;
2557                         else if (ret > 0)
2558                                 break;
2559                         continue;
2560                 }
2561
2562                 btrfs_item_key_to_cpu(l, &key, slot);
2563
2564                 if (key.objectid != btrfs_ino(inode))
2565                         break;
2566                 if (key.type != BTRFS_EXTENT_DATA_KEY)
2567                         break;
2568                 if (key.offset >= new->file_pos + new->len)
2569                         break;
2570
2571                 extent = btrfs_item_ptr(l, slot, struct btrfs_file_extent_item);
2572
2573                 num_bytes = btrfs_file_extent_num_bytes(l, extent);
2574                 if (key.offset + num_bytes < new->file_pos)
2575                         goto next;
2576
2577                 disk_bytenr = btrfs_file_extent_disk_bytenr(l, extent);
2578                 if (!disk_bytenr)
2579                         goto next;
2580
2581                 extent_offset = btrfs_file_extent_offset(l, extent);
2582
2583                 old = kmalloc(sizeof(*old), GFP_NOFS);
2584                 if (!old)
2585                         goto out_free_path;
2586
2587                 offset = max(new->file_pos, key.offset);
2588                 end = min(new->file_pos + new->len, key.offset + num_bytes);
2589
2590                 old->bytenr = disk_bytenr;
2591                 old->extent_offset = extent_offset;
2592                 old->offset = offset - key.offset;
2593                 old->len = end - offset;
2594                 old->new = new;
2595                 old->count = 0;
2596                 list_add_tail(&old->list, &new->head);
2597 next:
2598                 path->slots[0]++;
2599                 cond_resched();
2600         }
2601
2602         btrfs_free_path(path);
2603         atomic_inc(&root->fs_info->defrag_running);
2604
2605         return new;
2606
2607 out_free_path:
2608         btrfs_free_path(path);
2609 out_kfree:
2610         free_sa_defrag_extent(new);
2611         return NULL;
2612 }
2613
2614 static void btrfs_release_delalloc_bytes(struct btrfs_root *root,
2615                                          u64 start, u64 len)
2616 {
2617         struct btrfs_block_group_cache *cache;
2618
2619         cache = btrfs_lookup_block_group(root->fs_info, start);
2620         ASSERT(cache);
2621
2622         spin_lock(&cache->lock);
2623         cache->delalloc_bytes -= len;
2624         spin_unlock(&cache->lock);
2625
2626         btrfs_put_block_group(cache);
2627 }
2628
2629 /* as ordered data IO finishes, this gets called so we can finish
2630  * an ordered extent if the range of bytes in the file it covers are
2631  * fully written.
2632  */
2633 static int btrfs_finish_ordered_io(struct btrfs_ordered_extent *ordered_extent)
2634 {
2635         struct inode *inode = ordered_extent->inode;
2636         struct btrfs_root *root = BTRFS_I(inode)->root;
2637         struct btrfs_trans_handle *trans = NULL;
2638         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
2639         struct extent_state *cached_state = NULL;
2640         struct new_sa_defrag_extent *new = NULL;
2641         int compress_type = 0;
2642         int ret = 0;
2643         u64 logical_len = ordered_extent->len;
2644         bool nolock;
2645         bool truncated = false;
2646
2647         nolock = btrfs_is_free_space_inode(inode);
2648
2649         if (test_bit(BTRFS_ORDERED_IOERR, &ordered_extent->flags)) {
2650                 ret = -EIO;
2651                 goto out;
2652         }
2653
2654         if (test_bit(BTRFS_ORDERED_TRUNCATED, &ordered_extent->flags)) {
2655                 truncated = true;
2656                 logical_len = ordered_extent->truncated_len;
2657                 /* Truncated the entire extent, don't bother adding */
2658                 if (!logical_len)
2659                         goto out;
2660         }
2661
2662         if (test_bit(BTRFS_ORDERED_NOCOW, &ordered_extent->flags)) {
2663                 BUG_ON(!list_empty(&ordered_extent->list)); /* Logic error */
2664                 btrfs_ordered_update_i_size(inode, 0, ordered_extent);
2665                 if (nolock)
2666                         trans = btrfs_join_transaction_nolock(root);
2667                 else
2668                         trans = btrfs_join_transaction(root);
2669                 if (IS_ERR(trans)) {
2670                         ret = PTR_ERR(trans);
2671                         trans = NULL;
2672                         goto out;
2673                 }
2674                 trans->block_rsv = &root->fs_info->delalloc_block_rsv;
2675                 ret = btrfs_update_inode_fallback(trans, root, inode);
2676                 if (ret) /* -ENOMEM or corruption */
2677                         btrfs_abort_transaction(trans, root, ret);
2678                 goto out;
2679         }
2680
2681         lock_extent_bits(io_tree, ordered_extent->file_offset,
2682                          ordered_extent->file_offset + ordered_extent->len - 1,
2683                          0, &cached_state);
2684
2685         ret = test_range_bit(io_tree, ordered_extent->file_offset,
2686                         ordered_extent->file_offset + ordered_extent->len - 1,
2687                         EXTENT_DEFRAG, 1, cached_state);
2688         if (ret) {
2689                 u64 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
2690                 if (0 && last_snapshot >= BTRFS_I(inode)->generation)
2691                         /* the inode is shared */
2692                         new = record_old_file_extents(inode, ordered_extent);
2693
2694                 clear_extent_bit(io_tree, ordered_extent->file_offset,
2695                         ordered_extent->file_offset + ordered_extent->len - 1,
2696                         EXTENT_DEFRAG, 0, 0, &cached_state, GFP_NOFS);
2697         }
2698
2699         if (nolock)
2700                 trans = btrfs_join_transaction_nolock(root);
2701         else
2702                 trans = btrfs_join_transaction(root);
2703         if (IS_ERR(trans)) {
2704                 ret = PTR_ERR(trans);
2705                 trans = NULL;
2706                 goto out_unlock;
2707         }
2708
2709         trans->block_rsv = &root->fs_info->delalloc_block_rsv;
2710
2711         if (test_bit(BTRFS_ORDERED_COMPRESSED, &ordered_extent->flags))
2712                 compress_type = ordered_extent->compress_type;
2713         if (test_bit(BTRFS_ORDERED_PREALLOC, &ordered_extent->flags)) {
2714                 BUG_ON(compress_type);
2715                 ret = btrfs_mark_extent_written(trans, inode,
2716                                                 ordered_extent->file_offset,
2717                                                 ordered_extent->file_offset +
2718                                                 logical_len);
2719         } else {
2720                 BUG_ON(root == root->fs_info->tree_root);
2721                 ret = insert_reserved_file_extent(trans, inode,
2722                                                 ordered_extent->file_offset,
2723                                                 ordered_extent->start,
2724                                                 ordered_extent->disk_len,
2725                                                 logical_len, logical_len,
2726                                                 compress_type, 0, 0,
2727                                                 BTRFS_FILE_EXTENT_REG);
2728                 if (!ret)
2729                         btrfs_release_delalloc_bytes(root,
2730                                                      ordered_extent->start,
2731                                                      ordered_extent->disk_len);
2732         }
2733         unpin_extent_cache(&BTRFS_I(inode)->extent_tree,
2734                            ordered_extent->file_offset, ordered_extent->len,
2735                            trans->transid);
2736         if (ret < 0) {
2737                 btrfs_abort_transaction(trans, root, ret);
2738                 goto out_unlock;
2739         }
2740
2741         add_pending_csums(trans, inode, ordered_extent->file_offset,
2742                           &ordered_extent->list);
2743
2744         btrfs_ordered_update_i_size(inode, 0, ordered_extent);
2745         ret = btrfs_update_inode_fallback(trans, root, inode);
2746         if (ret) { /* -ENOMEM or corruption */
2747                 btrfs_abort_transaction(trans, root, ret);
2748                 goto out_unlock;
2749         }
2750         ret = 0;
2751 out_unlock:
2752         unlock_extent_cached(io_tree, ordered_extent->file_offset,
2753                              ordered_extent->file_offset +
2754                              ordered_extent->len - 1, &cached_state, GFP_NOFS);
2755 out:
2756         if (root != root->fs_info->tree_root)
2757                 btrfs_delalloc_release_metadata(inode, ordered_extent->len);
2758         if (trans)
2759                 btrfs_end_transaction(trans, root);
2760
2761         if (ret || truncated) {
2762                 u64 start, end;
2763
2764                 if (truncated)
2765                         start = ordered_extent->file_offset + logical_len;
2766                 else
2767                         start = ordered_extent->file_offset;
2768                 end = ordered_extent->file_offset + ordered_extent->len - 1;
2769                 clear_extent_uptodate(io_tree, start, end, NULL, GFP_NOFS);
2770
2771                 /* Drop the cache for the part of the extent we didn't write. */
2772                 btrfs_drop_extent_cache(inode, start, end, 0);
2773
2774                 /*
2775                  * If the ordered extent had an IOERR or something else went
2776                  * wrong we need to return the space for this ordered extent
2777                  * back to the allocator.  We only free the extent in the
2778                  * truncated case if we didn't write out the extent at all.
2779                  */
2780                 if ((ret || !logical_len) &&
2781                     !test_bit(BTRFS_ORDERED_NOCOW, &ordered_extent->flags) &&
2782                     !test_bit(BTRFS_ORDERED_PREALLOC, &ordered_extent->flags))
2783                         btrfs_free_reserved_extent(root, ordered_extent->start,
2784                                                    ordered_extent->disk_len, 1);
2785         }
2786
2787
2788         /*
2789          * This needs to be done to make sure anybody waiting knows we are done
2790          * updating everything for this ordered extent.
2791          */
2792         btrfs_remove_ordered_extent(inode, ordered_extent);
2793
2794         /* for snapshot-aware defrag */
2795         if (new) {
2796                 if (ret) {
2797                         free_sa_defrag_extent(new);
2798                         atomic_dec(&root->fs_info->defrag_running);
2799                 } else {
2800                         relink_file_extents(new);
2801                 }
2802         }
2803
2804         /* once for us */
2805         btrfs_put_ordered_extent(ordered_extent);
2806         /* once for the tree */
2807         btrfs_put_ordered_extent(ordered_extent);
2808
2809         return ret;
2810 }
2811
2812 static void finish_ordered_fn(struct btrfs_work *work)
2813 {
2814         struct btrfs_ordered_extent *ordered_extent;
2815         ordered_extent = container_of(work, struct btrfs_ordered_extent, work);
2816         btrfs_finish_ordered_io(ordered_extent);
2817 }
2818
2819 static int btrfs_writepage_end_io_hook(struct page *page, u64 start, u64 end,
2820                                 struct extent_state *state, int uptodate)
2821 {
2822         struct inode *inode = page->mapping->host;
2823         struct btrfs_root *root = BTRFS_I(inode)->root;
2824         struct btrfs_ordered_extent *ordered_extent = NULL;
2825         struct btrfs_workqueue *workers;
2826
2827         trace_btrfs_writepage_end_io_hook(page, start, end, uptodate);
2828
2829         ClearPagePrivate2(page);
2830         if (!btrfs_dec_test_ordered_pending(inode, &ordered_extent, start,
2831                                             end - start + 1, uptodate))
2832                 return 0;
2833
2834         btrfs_init_work(&ordered_extent->work, finish_ordered_fn, NULL, NULL);
2835
2836         if (btrfs_is_free_space_inode(inode))
2837                 workers = root->fs_info->endio_freespace_worker;
2838         else
2839                 workers = root->fs_info->endio_write_workers;
2840         btrfs_queue_work(workers, &ordered_extent->work);
2841
2842         return 0;
2843 }
2844
2845 /*
2846  * when reads are done, we need to check csums to verify the data is correct
2847  * if there's a match, we allow the bio to finish.  If not, the code in
2848  * extent_io.c will try to find good copies for us.
2849  */
2850 static int btrfs_readpage_end_io_hook(struct btrfs_io_bio *io_bio,
2851                                       u64 phy_offset, struct page *page,
2852                                       u64 start, u64 end, int mirror)
2853 {
2854         size_t offset = start - page_offset(page);
2855         struct inode *inode = page->mapping->host;
2856         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
2857         char *kaddr;
2858         struct btrfs_root *root = BTRFS_I(inode)->root;
2859         u32 csum_expected;
2860         u32 csum = ~(u32)0;
2861         static DEFINE_RATELIMIT_STATE(_rs, DEFAULT_RATELIMIT_INTERVAL,
2862                                       DEFAULT_RATELIMIT_BURST);
2863
2864         if (PageChecked(page)) {
2865                 ClearPageChecked(page);
2866                 goto good;
2867         }
2868
2869         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)
2870                 goto good;
2871
2872         if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID &&
2873             test_range_bit(io_tree, start, end, EXTENT_NODATASUM, 1, NULL)) {
2874                 clear_extent_bits(io_tree, start, end, EXTENT_NODATASUM,
2875                                   GFP_NOFS);
2876                 return 0;
2877         }
2878
2879         phy_offset >>= inode->i_sb->s_blocksize_bits;
2880         csum_expected = *(((u32 *)io_bio->csum) + phy_offset);
2881
2882         kaddr = kmap_atomic(page);
2883         csum = btrfs_csum_data(kaddr + offset, csum,  end - start + 1);
2884         btrfs_csum_final(csum, (char *)&csum);
2885         if (csum != csum_expected)
2886                 goto zeroit;
2887
2888         kunmap_atomic(kaddr);
2889 good:
2890         return 0;
2891
2892 zeroit:
2893         if (__ratelimit(&_rs))
2894                 btrfs_info(root->fs_info, "csum failed ino %llu off %llu csum %u expected csum %u",
2895                         btrfs_ino(page->mapping->host), start, csum, csum_expected);
2896         memset(kaddr + offset, 1, end - start + 1);
2897         flush_dcache_page(page);
2898         kunmap_atomic(kaddr);
2899         if (csum_expected == 0)
2900                 return 0;
2901         return -EIO;
2902 }
2903
2904 struct delayed_iput {
2905         struct list_head list;
2906         struct inode *inode;
2907 };
2908
2909 /* JDM: If this is fs-wide, why can't we add a pointer to
2910  * btrfs_inode instead and avoid the allocation? */
2911 void btrfs_add_delayed_iput(struct inode *inode)
2912 {
2913         struct btrfs_fs_info *fs_info = BTRFS_I(inode)->root->fs_info;
2914         struct delayed_iput *delayed;
2915
2916         if (atomic_add_unless(&inode->i_count, -1, 1))
2917                 return;
2918
2919         delayed = kmalloc(sizeof(*delayed), GFP_NOFS | __GFP_NOFAIL);
2920         delayed->inode = inode;
2921
2922         spin_lock(&fs_info->delayed_iput_lock);
2923         list_add_tail(&delayed->list, &fs_info->delayed_iputs);
2924         spin_unlock(&fs_info->delayed_iput_lock);
2925 }
2926
2927 void btrfs_run_delayed_iputs(struct btrfs_root *root)
2928 {
2929         LIST_HEAD(list);
2930         struct btrfs_fs_info *fs_info = root->fs_info;
2931         struct delayed_iput *delayed;
2932         int empty;
2933
2934         spin_lock(&fs_info->delayed_iput_lock);
2935         empty = list_empty(&fs_info->delayed_iputs);
2936         spin_unlock(&fs_info->delayed_iput_lock);
2937         if (empty)
2938                 return;
2939
2940         spin_lock(&fs_info->delayed_iput_lock);
2941         list_splice_init(&fs_info->delayed_iputs, &list);
2942         spin_unlock(&fs_info->delayed_iput_lock);
2943
2944         while (!list_empty(&list)) {
2945                 delayed = list_entry(list.next, struct delayed_iput, list);
2946                 list_del(&delayed->list);
2947                 iput(delayed->inode);
2948                 kfree(delayed);
2949         }
2950 }
2951
2952 /*
2953  * This is called in transaction commit time. If there are no orphan
2954  * files in the subvolume, it removes orphan item and frees block_rsv
2955  * structure.
2956  */
2957 void btrfs_orphan_commit_root(struct btrfs_trans_handle *trans,
2958                               struct btrfs_root *root)
2959 {
2960         struct btrfs_block_rsv *block_rsv;
2961         int ret;
2962
2963         if (atomic_read(&root->orphan_inodes) ||
2964             root->orphan_cleanup_state != ORPHAN_CLEANUP_DONE)
2965                 return;
2966
2967         spin_lock(&root->orphan_lock);
2968         if (atomic_read(&root->orphan_inodes)) {
2969                 spin_unlock(&root->orphan_lock);
2970                 return;
2971         }
2972
2973         if (root->orphan_cleanup_state != ORPHAN_CLEANUP_DONE) {
2974                 spin_unlock(&root->orphan_lock);
2975                 return;
2976         }
2977
2978         block_rsv = root->orphan_block_rsv;
2979         root->orphan_block_rsv = NULL;
2980         spin_unlock(&root->orphan_lock);
2981
2982         if (test_bit(BTRFS_ROOT_ORPHAN_ITEM_INSERTED, &root->state) &&
2983             btrfs_root_refs(&root->root_item) > 0) {
2984                 ret = btrfs_del_orphan_item(trans, root->fs_info->tree_root,
2985                                             root->root_key.objectid);
2986                 if (ret)
2987                         btrfs_abort_transaction(trans, root, ret);
2988                 else
2989                         clear_bit(BTRFS_ROOT_ORPHAN_ITEM_INSERTED,
2990                                   &root->state);
2991         }
2992
2993         if (block_rsv) {
2994                 WARN_ON(block_rsv->size > 0);
2995                 btrfs_free_block_rsv(root, block_rsv);
2996         }
2997 }
2998
2999 /*
3000  * This creates an orphan entry for the given inode in case something goes
3001  * wrong in the middle of an unlink/truncate.
3002  *
3003  * NOTE: caller of this function should reserve 5 units of metadata for
3004  *       this function.
3005  */
3006 int btrfs_orphan_add(struct btrfs_trans_handle *trans, struct inode *inode)
3007 {
3008         struct btrfs_root *root = BTRFS_I(inode)->root;
3009         struct btrfs_block_rsv *block_rsv = NULL;
3010         int reserve = 0;
3011         int insert = 0;
3012         int ret;
3013
3014         if (!root->orphan_block_rsv) {
3015                 block_rsv = btrfs_alloc_block_rsv(root, BTRFS_BLOCK_RSV_TEMP);
3016                 if (!block_rsv)
3017                         return -ENOMEM;
3018         }
3019
3020         spin_lock(&root->orphan_lock);
3021         if (!root->orphan_block_rsv) {
3022                 root->orphan_block_rsv = block_rsv;
3023         } else if (block_rsv) {
3024                 btrfs_free_block_rsv(root, block_rsv);
3025                 block_rsv = NULL;
3026         }
3027
3028         if (!test_and_set_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
3029                               &BTRFS_I(inode)->runtime_flags)) {
3030 #if 0
3031                 /*
3032                  * For proper ENOSPC handling, we should do orphan
3033                  * cleanup when mounting. But this introduces backward
3034                  * compatibility issue.
3035                  */
3036                 if (!xchg(&root->orphan_item_inserted, 1))
3037                         insert = 2;
3038                 else
3039                         insert = 1;
3040 #endif
3041                 insert = 1;
3042                 atomic_inc(&root->orphan_inodes);
3043         }
3044
3045         if (!test_and_set_bit(BTRFS_INODE_ORPHAN_META_RESERVED,
3046                               &BTRFS_I(inode)->runtime_flags))
3047                 reserve = 1;
3048         spin_unlock(&root->orphan_lock);
3049
3050         /* grab metadata reservation from transaction handle */
3051         if (reserve) {
3052                 ret = btrfs_orphan_reserve_metadata(trans, inode);
3053                 BUG_ON(ret); /* -ENOSPC in reservation; Logic error? JDM */
3054         }
3055
3056         /* insert an orphan item to track this unlinked/truncated file */
3057         if (insert >= 1) {
3058                 ret = btrfs_insert_orphan_item(trans, root, btrfs_ino(inode));
3059                 if (ret) {
3060                         atomic_dec(&root->orphan_inodes);
3061                         if (reserve) {
3062                                 clear_bit(BTRFS_INODE_ORPHAN_META_RESERVED,
3063                                           &BTRFS_I(inode)->runtime_flags);
3064                                 btrfs_orphan_release_metadata(inode);
3065                         }
3066                         if (ret != -EEXIST) {
3067                                 clear_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
3068                                           &BTRFS_I(inode)->runtime_flags);
3069                                 btrfs_abort_transaction(trans, root, ret);
3070                                 return ret;
3071                         }
3072                 }
3073                 ret = 0;
3074         }
3075
3076         /* insert an orphan item to track subvolume contains orphan files */
3077         if (insert >= 2) {
3078                 ret = btrfs_insert_orphan_item(trans, root->fs_info->tree_root,
3079                                                root->root_key.objectid);
3080                 if (ret && ret != -EEXIST) {
3081                         btrfs_abort_transaction(trans, root, ret);
3082                         return ret;
3083                 }
3084         }
3085         return 0;
3086 }
3087
3088 /*
3089  * We have done the truncate/delete so we can go ahead and remove the orphan
3090  * item for this particular inode.
3091  */
3092 static int btrfs_orphan_del(struct btrfs_trans_handle *trans,
3093                             struct inode *inode)
3094 {
3095         struct btrfs_root *root = BTRFS_I(inode)->root;
3096         int delete_item = 0;
3097         int release_rsv = 0;
3098         int ret = 0;
3099
3100         spin_lock(&root->orphan_lock);
3101         if (test_and_clear_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
3102                                &BTRFS_I(inode)->runtime_flags))
3103                 delete_item = 1;
3104
3105         if (test_and_clear_bit(BTRFS_INODE_ORPHAN_META_RESERVED,
3106                                &BTRFS_I(inode)->runtime_flags))
3107                 release_rsv = 1;
3108         spin_unlock(&root->orphan_lock);
3109
3110         if (delete_item) {
3111                 atomic_dec(&root->orphan_inodes);
3112                 if (trans)
3113                         ret = btrfs_del_orphan_item(trans, root,
3114                                                     btrfs_ino(inode));
3115         }
3116
3117         if (release_rsv)
3118                 btrfs_orphan_release_metadata(inode);
3119
3120         return ret;
3121 }
3122
3123 /*
3124  * this cleans up any orphans that may be left on the list from the last use
3125  * of this root.
3126  */
3127 int btrfs_orphan_cleanup(struct btrfs_root *root)
3128 {
3129         struct btrfs_path *path;
3130         struct extent_buffer *leaf;
3131         struct btrfs_key key, found_key;
3132         struct btrfs_trans_handle *trans;
3133         struct inode *inode;
3134         u64 last_objectid = 0;
3135         int ret = 0, nr_unlink = 0, nr_truncate = 0;
3136
3137         if (cmpxchg(&root->orphan_cleanup_state, 0, ORPHAN_CLEANUP_STARTED))
3138                 return 0;
3139
3140         path = btrfs_alloc_path();
3141         if (!path) {
3142                 ret = -ENOMEM;
3143                 goto out;
3144         }
3145         path->reada = -1;
3146
3147         key.objectid = BTRFS_ORPHAN_OBJECTID;
3148         btrfs_set_key_type(&key, BTRFS_ORPHAN_ITEM_KEY);
3149         key.offset = (u64)-1;
3150
3151         while (1) {
3152                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3153                 if (ret < 0)
3154                         goto out;
3155
3156                 /*
3157                  * if ret == 0 means we found what we were searching for, which
3158                  * is weird, but possible, so only screw with path if we didn't
3159                  * find the key and see if we have stuff that matches
3160                  */
3161                 if (ret > 0) {
3162                         ret = 0;
3163                         if (path->slots[0] == 0)
3164                                 break;
3165                         path->slots[0]--;
3166                 }
3167
3168                 /* pull out the item */
3169                 leaf = path->nodes[0];
3170                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
3171
3172                 /* make sure the item matches what we want */
3173                 if (found_key.objectid != BTRFS_ORPHAN_OBJECTID)
3174                         break;
3175                 if (btrfs_key_type(&found_key) != BTRFS_ORPHAN_ITEM_KEY)
3176                         break;
3177
3178                 /* release the path since we're done with it */
3179                 btrfs_release_path(path);
3180
3181                 /*
3182                  * this is where we are basically btrfs_lookup, without the
3183                  * crossing root thing.  we store the inode number in the
3184                  * offset of the orphan item.
3185                  */
3186
3187                 if (found_key.offset == last_objectid) {
3188                         btrfs_err(root->fs_info,
3189                                 "Error removing orphan entry, stopping orphan cleanup");
3190                         ret = -EINVAL;
3191                         goto out;
3192                 }
3193
3194                 last_objectid = found_key.offset;
3195
3196                 found_key.objectid = found_key.offset;
3197                 found_key.type = BTRFS_INODE_ITEM_KEY;
3198                 found_key.offset = 0;
3199                 inode = btrfs_iget(root->fs_info->sb, &found_key, root, NULL);
3200                 ret = PTR_ERR_OR_ZERO(inode);
3201                 if (ret && ret != -ESTALE)
3202                         goto out;
3203
3204                 if (ret == -ESTALE && root == root->fs_info->tree_root) {
3205                         struct btrfs_root *dead_root;
3206                         struct btrfs_fs_info *fs_info = root->fs_info;
3207                         int is_dead_root = 0;
3208
3209                         /*
3210                          * this is an orphan in the tree root. Currently these
3211                          * could come from 2 sources:
3212                          *  a) a snapshot deletion in progress
3213                          *  b) a free space cache inode
3214                          * We need to distinguish those two, as the snapshot
3215                          * orphan must not get deleted.
3216                          * find_dead_roots already ran before us, so if this
3217                          * is a snapshot deletion, we should find the root
3218                          * in the dead_roots list
3219                          */
3220                         spin_lock(&fs_info->trans_lock);
3221                         list_for_each_entry(dead_root, &fs_info->dead_roots,
3222                                             root_list) {
3223                                 if (dead_root->root_key.objectid ==
3224                                     found_key.objectid) {
3225                                         is_dead_root = 1;
3226                                         break;
3227                                 }
3228                         }
3229                         spin_unlock(&fs_info->trans_lock);
3230                         if (is_dead_root) {
3231                                 /* prevent this orphan from being found again */
3232                                 key.offset = found_key.objectid - 1;
3233                                 continue;
3234                         }
3235                 }
3236                 /*
3237                  * Inode is already gone but the orphan item is still there,
3238                  * kill the orphan item.
3239                  */
3240                 if (ret == -ESTALE) {
3241                         trans = btrfs_start_transaction(root, 1);
3242                         if (IS_ERR(trans)) {
3243                                 ret = PTR_ERR(trans);
3244                                 goto out;
3245                         }
3246                         btrfs_debug(root->fs_info, "auto deleting %Lu",
3247                                 found_key.objectid);
3248                         ret = btrfs_del_orphan_item(trans, root,
3249                                                     found_key.objectid);
3250                         btrfs_end_transaction(trans, root);
3251                         if (ret)
3252                                 goto out;
3253                         continue;
3254                 }
3255
3256                 /*
3257                  * add this inode to the orphan list so btrfs_orphan_del does
3258                  * the proper thing when we hit it
3259                  */
3260                 set_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
3261                         &BTRFS_I(inode)->runtime_flags);
3262                 atomic_inc(&root->orphan_inodes);
3263
3264                 /* if we have links, this was a truncate, lets do that */
3265                 if (inode->i_nlink) {
3266                         if (WARN_ON(!S_ISREG(inode->i_mode))) {
3267                                 iput(inode);
3268                                 continue;
3269                         }
3270                         nr_truncate++;
3271
3272                         /* 1 for the orphan item deletion. */
3273                         trans = btrfs_start_transaction(root, 1);
3274                         if (IS_ERR(trans)) {
3275                                 iput(inode);
3276                                 ret = PTR_ERR(trans);
3277                                 goto out;
3278                         }
3279                         ret = btrfs_orphan_add(trans, inode);
3280                         btrfs_end_transaction(trans, root);
3281                         if (ret) {
3282                                 iput(inode);
3283                                 goto out;
3284                         }
3285
3286                         ret = btrfs_truncate(inode);
3287                         if (ret)
3288                                 btrfs_orphan_del(NULL, inode);
3289                 } else {
3290                         nr_unlink++;
3291                 }
3292
3293                 /* this will do delete_inode and everything for us */
3294                 iput(inode);
3295                 if (ret)
3296                         goto out;
3297         }
3298         /* release the path since we're done with it */
3299         btrfs_release_path(path);
3300
3301         root->orphan_cleanup_state = ORPHAN_CLEANUP_DONE;
3302
3303         if (root->orphan_block_rsv)
3304                 btrfs_block_rsv_release(root, root->orphan_block_rsv,
3305                                         (u64)-1);
3306
3307         if (root->orphan_block_rsv ||
3308             test_bit(BTRFS_ROOT_ORPHAN_ITEM_INSERTED, &root->state)) {
3309                 trans = btrfs_join_transaction(root);
3310                 if (!IS_ERR(trans))
3311                         btrfs_end_transaction(trans, root);
3312         }
3313
3314         if (nr_unlink)
3315                 btrfs_debug(root->fs_info, "unlinked %d orphans", nr_unlink);
3316         if (nr_truncate)
3317                 btrfs_debug(root->fs_info, "truncated %d orphans", nr_truncate);
3318
3319 out:
3320         if (ret)
3321                 btrfs_crit(root->fs_info,
3322                         "could not do orphan cleanup %d", ret);
3323         btrfs_free_path(path);
3324         return ret;
3325 }
3326
3327 /*
3328  * very simple check to peek ahead in the leaf looking for xattrs.  If we
3329  * don't find any xattrs, we know there can't be any acls.
3330  *
3331  * slot is the slot the inode is in, objectid is the objectid of the inode
3332  */
3333 static noinline int acls_after_inode_item(struct extent_buffer *leaf,
3334                                           int slot, u64 objectid,
3335                                           int *first_xattr_slot)
3336 {
3337         u32 nritems = btrfs_header_nritems(leaf);
3338         struct btrfs_key found_key;
3339         static u64 xattr_access = 0;
3340         static u64 xattr_default = 0;
3341         int scanned = 0;
3342
3343         if (!xattr_access) {
3344                 xattr_access = btrfs_name_hash(POSIX_ACL_XATTR_ACCESS,
3345                                         strlen(POSIX_ACL_XATTR_ACCESS));
3346                 xattr_default = btrfs_name_hash(POSIX_ACL_XATTR_DEFAULT,
3347                                         strlen(POSIX_ACL_XATTR_DEFAULT));
3348         }
3349
3350         slot++;
3351         *first_xattr_slot = -1;
3352         while (slot < nritems) {
3353                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
3354
3355                 /* we found a different objectid, there must not be acls */
3356                 if (found_key.objectid != objectid)
3357                         return 0;
3358
3359                 /* we found an xattr, assume we've got an acl */
3360                 if (found_key.type == BTRFS_XATTR_ITEM_KEY) {
3361                         if (*first_xattr_slot == -1)
3362                                 *first_xattr_slot = slot;
3363                         if (found_key.offset == xattr_access ||
3364                             found_key.offset == xattr_default)
3365                                 return 1;
3366                 }
3367
3368                 /*
3369                  * we found a key greater than an xattr key, there can't
3370                  * be any acls later on
3371                  */
3372                 if (found_key.type > BTRFS_XATTR_ITEM_KEY)
3373                         return 0;
3374
3375                 slot++;
3376                 scanned++;
3377
3378                 /*
3379                  * it goes inode, inode backrefs, xattrs, extents,
3380                  * so if there are a ton of hard links to an inode there can
3381                  * be a lot of backrefs.  Don't waste time searching too hard,
3382                  * this is just an optimization
3383                  */
3384                 if (scanned >= 8)
3385                         break;
3386         }
3387         /* we hit the end of the leaf before we found an xattr or
3388          * something larger than an xattr.  We have to assume the inode
3389          * has acls
3390          */
3391         if (*first_xattr_slot == -1)
3392                 *first_xattr_slot = slot;
3393         return 1;
3394 }
3395
3396 /*
3397  * read an inode from the btree into the in-memory inode
3398  */
3399 static void btrfs_read_locked_inode(struct inode *inode)
3400 {
3401         struct btrfs_path *path;
3402         struct extent_buffer *leaf;
3403         struct btrfs_inode_item *inode_item;
3404         struct btrfs_timespec *tspec;
3405         struct btrfs_root *root = BTRFS_I(inode)->root;
3406         struct btrfs_key location;
3407         unsigned long ptr;
3408         int maybe_acls;
3409         u32 rdev;
3410         int ret;
3411         bool filled = false;
3412         int first_xattr_slot;
3413
3414         ret = btrfs_fill_inode(inode, &rdev);
3415         if (!ret)
3416                 filled = true;
3417
3418         path = btrfs_alloc_path();
3419         if (!path)
3420                 goto make_bad;
3421
3422         memcpy(&location, &BTRFS_I(inode)->location, sizeof(location));
3423
3424         ret = btrfs_lookup_inode(NULL, root, path, &location, 0);
3425         if (ret)
3426                 goto make_bad;
3427
3428         leaf = path->nodes[0];
3429
3430         if (filled)
3431                 goto cache_index;
3432
3433         inode_item = btrfs_item_ptr(leaf, path->slots[0],
3434                                     struct btrfs_inode_item);
3435         inode->i_mode = btrfs_inode_mode(leaf, inode_item);
3436         set_nlink(inode, btrfs_inode_nlink(leaf, inode_item));
3437         i_uid_write(inode, btrfs_inode_uid(leaf, inode_item));
3438         i_gid_write(inode, btrfs_inode_gid(leaf, inode_item));
3439         btrfs_i_size_write(inode, btrfs_inode_size(leaf, inode_item));
3440
3441         tspec = btrfs_inode_atime(inode_item);
3442         inode->i_atime.tv_sec = btrfs_timespec_sec(leaf, tspec);
3443         inode->i_atime.tv_nsec = btrfs_timespec_nsec(leaf, tspec);
3444
3445         tspec = btrfs_inode_mtime(inode_item);
3446         inode->i_mtime.tv_sec = btrfs_timespec_sec(leaf, tspec);
3447         inode->i_mtime.tv_nsec = btrfs_timespec_nsec(leaf, tspec);
3448
3449         tspec = btrfs_inode_ctime(inode_item);
3450         inode->i_ctime.tv_sec = btrfs_timespec_sec(leaf, tspec);
3451         inode->i_ctime.tv_nsec = btrfs_timespec_nsec(leaf, tspec);
3452
3453         inode_set_bytes(inode, btrfs_inode_nbytes(leaf, inode_item));
3454         BTRFS_I(inode)->generation = btrfs_inode_generation(leaf, inode_item);
3455         BTRFS_I(inode)->last_trans = btrfs_inode_transid(leaf, inode_item);
3456
3457         /*
3458          * If we were modified in the current generation and evicted from memory
3459          * and then re-read we need to do a full sync since we don't have any
3460          * idea about which extents were modified before we were evicted from
3461          * cache.
3462          */
3463         if (BTRFS_I(inode)->last_trans == root->fs_info->generation)
3464                 set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
3465                         &BTRFS_I(inode)->runtime_flags);
3466
3467         inode->i_version = btrfs_inode_sequence(leaf, inode_item);
3468         inode->i_generation = BTRFS_I(inode)->generation;
3469         inode->i_rdev = 0;
3470         rdev = btrfs_inode_rdev(leaf, inode_item);
3471
3472         BTRFS_I(inode)->index_cnt = (u64)-1;
3473         BTRFS_I(inode)->flags = btrfs_inode_flags(leaf, inode_item);
3474
3475 cache_index:
3476         path->slots[0]++;
3477         if (inode->i_nlink != 1 ||
3478             path->slots[0] >= btrfs_header_nritems(leaf))
3479                 goto cache_acl;
3480
3481         btrfs_item_key_to_cpu(leaf, &location, path->slots[0]);
3482         if (location.objectid != btrfs_ino(inode))
3483                 goto cache_acl;
3484
3485         ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
3486         if (location.type == BTRFS_INODE_REF_KEY) {
3487                 struct btrfs_inode_ref *ref;
3488
3489                 ref = (struct btrfs_inode_ref *)ptr;
3490                 BTRFS_I(inode)->dir_index = btrfs_inode_ref_index(leaf, ref);
3491         } else if (location.type == BTRFS_INODE_EXTREF_KEY) {
3492                 struct btrfs_inode_extref *extref;
3493
3494                 extref = (struct btrfs_inode_extref *)ptr;
3495                 BTRFS_I(inode)->dir_index = btrfs_inode_extref_index(leaf,
3496                                                                      extref);
3497         }
3498 cache_acl:
3499         /*
3500          * try to precache a NULL acl entry for files that don't have
3501          * any xattrs or acls
3502          */
3503         maybe_acls = acls_after_inode_item(leaf, path->slots[0],
3504                                            btrfs_ino(inode), &first_xattr_slot);
3505         if (first_xattr_slot != -1) {
3506                 path->slots[0] = first_xattr_slot;
3507                 ret = btrfs_load_inode_props(inode, path);
3508                 if (ret)
3509                         btrfs_err(root->fs_info,
3510                                   "error loading props for ino %llu (root %llu): %d",
3511                                   btrfs_ino(inode),
3512                                   root->root_key.objectid, ret);
3513         }
3514         btrfs_free_path(path);
3515
3516         if (!maybe_acls)
3517                 cache_no_acl(inode);
3518
3519         switch (inode->i_mode & S_IFMT) {
3520         case S_IFREG:
3521                 inode->i_mapping->a_ops = &btrfs_aops;
3522                 inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
3523                 BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
3524                 inode->i_fop = &btrfs_file_operations;
3525                 inode->i_op = &btrfs_file_inode_operations;
3526                 break;
3527         case S_IFDIR:
3528                 inode->i_fop = &btrfs_dir_file_operations;
3529                 if (root == root->fs_info->tree_root)
3530                         inode->i_op = &btrfs_dir_ro_inode_operations;
3531                 else
3532                         inode->i_op = &btrfs_dir_inode_operations;
3533                 break;
3534         case S_IFLNK:
3535                 inode->i_op = &btrfs_symlink_inode_operations;
3536                 inode->i_mapping->a_ops = &btrfs_symlink_aops;
3537                 inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
3538                 break;
3539         default:
3540                 inode->i_op = &btrfs_special_inode_operations;
3541                 init_special_inode(inode, inode->i_mode, rdev);
3542                 break;
3543         }
3544
3545         btrfs_update_iflags(inode);
3546         return;
3547
3548 make_bad:
3549         btrfs_free_path(path);
3550         make_bad_inode(inode);
3551 }
3552
3553 /*
3554  * given a leaf and an inode, copy the inode fields into the leaf
3555  */
3556 static void fill_inode_item(struct btrfs_trans_handle *trans,
3557                             struct extent_buffer *leaf,
3558                             struct btrfs_inode_item *item,
3559                             struct inode *inode)
3560 {
3561         struct btrfs_map_token token;
3562
3563         btrfs_init_map_token(&token);
3564
3565         btrfs_set_token_inode_uid(leaf, item, i_uid_read(inode), &token);
3566         btrfs_set_token_inode_gid(leaf, item, i_gid_read(inode), &token);
3567         btrfs_set_token_inode_size(leaf, item, BTRFS_I(inode)->disk_i_size,
3568                                    &token);
3569         btrfs_set_token_inode_mode(leaf, item, inode->i_mode, &token);
3570         btrfs_set_token_inode_nlink(leaf, item, inode->i_nlink, &token);
3571
3572         btrfs_set_token_timespec_sec(leaf, btrfs_inode_atime(item),
3573                                      inode->i_atime.tv_sec, &token);
3574         btrfs_set_token_timespec_nsec(leaf, btrfs_inode_atime(item),
3575                                       inode->i_atime.tv_nsec, &token);
3576
3577         btrfs_set_token_timespec_sec(leaf, btrfs_inode_mtime(item),
3578                                      inode->i_mtime.tv_sec, &token);
3579         btrfs_set_token_timespec_nsec(leaf, btrfs_inode_mtime(item),
3580                                       inode->i_mtime.tv_nsec, &token);
3581
3582         btrfs_set_token_timespec_sec(leaf, btrfs_inode_ctime(item),
3583                                      inode->i_ctime.tv_sec, &token);
3584         btrfs_set_token_timespec_nsec(leaf, btrfs_inode_ctime(item),
3585                                       inode->i_ctime.tv_nsec, &token);
3586
3587         btrfs_set_token_inode_nbytes(leaf, item, inode_get_bytes(inode),
3588                                      &token);
3589         btrfs_set_token_inode_generation(leaf, item, BTRFS_I(inode)->generation,
3590                                          &token);
3591         btrfs_set_token_inode_sequence(leaf, item, inode->i_version, &token);
3592         btrfs_set_token_inode_transid(leaf, item, trans->transid, &token);
3593         btrfs_set_token_inode_rdev(leaf, item, inode->i_rdev, &token);
3594         btrfs_set_token_inode_flags(leaf, item, BTRFS_I(inode)->flags, &token);
3595         btrfs_set_token_inode_block_group(leaf, item, 0, &token);
3596 }
3597
3598 /*
3599  * copy everything in the in-memory inode into the btree.
3600  */
3601 static noinline int btrfs_update_inode_item(struct btrfs_trans_handle *trans,
3602                                 struct btrfs_root *root, struct inode *inode)
3603 {
3604         struct btrfs_inode_item *inode_item;
3605         struct btrfs_path *path;
3606         struct extent_buffer *leaf;
3607         int ret;
3608
3609         path = btrfs_alloc_path();
3610         if (!path)
3611                 return -ENOMEM;
3612
3613         path->leave_spinning = 1;
3614         ret = btrfs_lookup_inode(trans, root, path, &BTRFS_I(inode)->location,
3615                                  1);
3616         if (ret) {
3617                 if (ret > 0)
3618                         ret = -ENOENT;
3619                 goto failed;
3620         }
3621
3622         leaf = path->nodes[0];
3623         inode_item = btrfs_item_ptr(leaf, path->slots[0],
3624                                     struct btrfs_inode_item);
3625
3626         fill_inode_item(trans, leaf, inode_item, inode);
3627         btrfs_mark_buffer_dirty(leaf);
3628         btrfs_set_inode_last_trans(trans, inode);
3629         ret = 0;
3630 failed:
3631         btrfs_free_path(path);
3632         return ret;
3633 }
3634
3635 /*
3636  * copy everything in the in-memory inode into the btree.
3637  */
3638 noinline int btrfs_update_inode(struct btrfs_trans_handle *trans,
3639                                 struct btrfs_root *root, struct inode *inode)
3640 {
3641         int ret;
3642
3643         /*
3644          * If the inode is a free space inode, we can deadlock during commit
3645          * if we put it into the delayed code.
3646          *
3647          * The data relocation inode should also be directly updated
3648          * without delay
3649          */
3650         if (!btrfs_is_free_space_inode(inode)
3651             && root->root_key.objectid != BTRFS_DATA_RELOC_TREE_OBJECTID) {
3652                 btrfs_update_root_times(trans, root);
3653
3654                 ret = btrfs_delayed_update_inode(trans, root, inode);
3655                 if (!ret)
3656                         btrfs_set_inode_last_trans(trans, inode);
3657                 return ret;
3658         }
3659
3660         return btrfs_update_inode_item(trans, root, inode);
3661 }
3662
3663 noinline int btrfs_update_inode_fallback(struct btrfs_trans_handle *trans,
3664                                          struct btrfs_root *root,
3665                                          struct inode *inode)
3666 {
3667         int ret;
3668
3669         ret = btrfs_update_inode(trans, root, inode);
3670         if (ret == -ENOSPC)
3671                 return btrfs_update_inode_item(trans, root, inode);
3672         return ret;
3673 }
3674
3675 /*
3676  * unlink helper that gets used here in inode.c and in the tree logging
3677  * recovery code.  It remove a link in a directory with a given name, and
3678  * also drops the back refs in the inode to the directory
3679  */
3680 static int __btrfs_unlink_inode(struct btrfs_trans_handle *trans,
3681                                 struct btrfs_root *root,
3682                                 struct inode *dir, struct inode *inode,
3683                                 const char *name, int name_len)
3684 {
3685         struct btrfs_path *path;
3686         int ret = 0;
3687         struct extent_buffer *leaf;
3688         struct btrfs_dir_item *di;
3689         struct btrfs_key key;
3690         u64 index;
3691         u64 ino = btrfs_ino(inode);
3692         u64 dir_ino = btrfs_ino(dir);
3693
3694         path = btrfs_alloc_path();
3695         if (!path) {
3696                 ret = -ENOMEM;
3697                 goto out;
3698         }
3699
3700         path->leave_spinning = 1;
3701         di = btrfs_lookup_dir_item(trans, root, path, dir_ino,
3702                                     name, name_len, -1);
3703         if (IS_ERR(di)) {
3704                 ret = PTR_ERR(di);
3705                 goto err;
3706         }
3707         if (!di) {
3708                 ret = -ENOENT;
3709                 goto err;
3710         }
3711         leaf = path->nodes[0];
3712         btrfs_dir_item_key_to_cpu(leaf, di, &key);
3713         ret = btrfs_delete_one_dir_name(trans, root, path, di);
3714         if (ret)
3715                 goto err;
3716         btrfs_release_path(path);
3717
3718         /*
3719          * If we don't have dir index, we have to get it by looking up
3720          * the inode ref, since we get the inode ref, remove it directly,
3721          * it is unnecessary to do delayed deletion.
3722          *
3723          * But if we have dir index, needn't search inode ref to get it.
3724          * Since the inode ref is close to the inode item, it is better
3725          * that we delay to delete it, and just do this deletion when
3726          * we update the inode item.
3727          */
3728         if (BTRFS_I(inode)->dir_index) {
3729                 ret = btrfs_delayed_delete_inode_ref(inode);
3730                 if (!ret) {
3731                         index = BTRFS_I(inode)->dir_index;
3732                         goto skip_backref;
3733                 }
3734         }
3735
3736         ret = btrfs_del_inode_ref(trans, root, name, name_len, ino,
3737                                   dir_ino, &index);
3738         if (ret) {
3739                 btrfs_info(root->fs_info,
3740                         "failed to delete reference to %.*s, inode %llu parent %llu",
3741                         name_len, name, ino, dir_ino);
3742                 btrfs_abort_transaction(trans, root, ret);
3743                 goto err;
3744         }
3745 skip_backref:
3746         ret = btrfs_delete_delayed_dir_index(trans, root, dir, index);
3747         if (ret) {
3748                 btrfs_abort_transaction(trans, root, ret);
3749                 goto err;
3750         }
3751
3752         ret = btrfs_del_inode_ref_in_log(trans, root, name, name_len,
3753                                          inode, dir_ino);
3754         if (ret != 0 && ret != -ENOENT) {
3755                 btrfs_abort_transaction(trans, root, ret);
3756                 goto err;
3757         }
3758
3759         ret = btrfs_del_dir_entries_in_log(trans, root, name, name_len,
3760                                            dir, index);
3761         if (ret == -ENOENT)
3762                 ret = 0;
3763         else if (ret)
3764                 btrfs_abort_transaction(trans, root, ret);
3765 err:
3766         btrfs_free_path(path);
3767         if (ret)
3768                 goto out;
3769
3770         btrfs_i_size_write(dir, dir->i_size - name_len * 2);
3771         inode_inc_iversion(inode);
3772         inode_inc_iversion(dir);
3773         inode->i_ctime = dir->i_mtime = dir->i_ctime = CURRENT_TIME;
3774         ret = btrfs_update_inode(trans, root, dir);
3775 out:
3776         return ret;
3777 }
3778
3779 int btrfs_unlink_inode(struct btrfs_trans_handle *trans,
3780                        struct btrfs_root *root,
3781                        struct inode *dir, struct inode *inode,
3782                        const char *name, int name_len)
3783 {
3784         int ret;
3785         ret = __btrfs_unlink_inode(trans, root, dir, inode, name, name_len);
3786         if (!ret) {
3787                 drop_nlink(inode);
3788                 ret = btrfs_update_inode(trans, root, inode);
3789         }
3790         return ret;
3791 }
3792
3793 /*
3794  * helper to start transaction for unlink and rmdir.
3795  *
3796  * unlink and rmdir are special in btrfs, they do not always free space, so
3797  * if we cannot make our reservations the normal way try and see if there is
3798  * plenty of slack room in the global reserve to migrate, otherwise we cannot
3799  * allow the unlink to occur.
3800  */
3801 static struct btrfs_trans_handle *__unlink_start_trans(struct inode *dir)
3802 {
3803         struct btrfs_trans_handle *trans;
3804         struct btrfs_root *root = BTRFS_I(dir)->root;
3805         int ret;
3806
3807         /*
3808          * 1 for the possible orphan item
3809          * 1 for the dir item
3810          * 1 for the dir index
3811          * 1 for the inode ref
3812          * 1 for the inode
3813          */
3814         trans = btrfs_start_transaction(root, 5);
3815         if (!IS_ERR(trans) || PTR_ERR(trans) != -ENOSPC)
3816                 return trans;
3817
3818         if (PTR_ERR(trans) == -ENOSPC) {
3819                 u64 num_bytes = btrfs_calc_trans_metadata_size(root, 5);
3820
3821                 trans = btrfs_start_transaction(root, 0);
3822                 if (IS_ERR(trans))
3823                         return trans;
3824                 ret = btrfs_cond_migrate_bytes(root->fs_info,
3825                                                &root->fs_info->trans_block_rsv,
3826                                                num_bytes, 5);
3827                 if (ret) {
3828                         btrfs_end_transaction(trans, root);
3829                         return ERR_PTR(ret);
3830                 }
3831                 trans->block_rsv = &root->fs_info->trans_block_rsv;
3832                 trans->bytes_reserved = num_bytes;
3833         }
3834         return trans;
3835 }
3836
3837 static int btrfs_unlink(struct inode *dir, struct dentry *dentry)
3838 {
3839         struct btrfs_root *root = BTRFS_I(dir)->root;
3840         struct btrfs_trans_handle *trans;
3841         struct inode *inode = dentry->d_inode;
3842         int ret;
3843
3844         trans = __unlink_start_trans(dir);
3845         if (IS_ERR(trans))
3846                 return PTR_ERR(trans);
3847
3848         btrfs_record_unlink_dir(trans, dir, dentry->d_inode, 0);
3849
3850         ret = btrfs_unlink_inode(trans, root, dir, dentry->d_inode,
3851                                  dentry->d_name.name, dentry->d_name.len);
3852         if (ret)
3853                 goto out;
3854
3855         if (inode->i_nlink == 0) {
3856                 ret = btrfs_orphan_add(trans, inode);
3857                 if (ret)
3858                         goto out;
3859         }
3860
3861 out:
3862         btrfs_end_transaction(trans, root);
3863         btrfs_btree_balance_dirty(root);
3864         return ret;
3865 }
3866
3867 int btrfs_unlink_subvol(struct btrfs_trans_handle *trans,
3868                         struct btrfs_root *root,
3869                         struct inode *dir, u64 objectid,
3870                         const char *name, int name_len)
3871 {
3872         struct btrfs_path *path;
3873         struct extent_buffer *leaf;
3874         struct btrfs_dir_item *di;
3875         struct btrfs_key key;
3876         u64 index;
3877         int ret;
3878         u64 dir_ino = btrfs_ino(dir);
3879
3880         path = btrfs_alloc_path();
3881         if (!path)
3882                 return -ENOMEM;
3883
3884         di = btrfs_lookup_dir_item(trans, root, path, dir_ino,
3885                                    name, name_len, -1);
3886         if (IS_ERR_OR_NULL(di)) {
3887                 if (!di)
3888                         ret = -ENOENT;
3889                 else
3890                         ret = PTR_ERR(di);
3891                 goto out;
3892         }
3893
3894         leaf = path->nodes[0];
3895         btrfs_dir_item_key_to_cpu(leaf, di, &key);
3896         WARN_ON(key.type != BTRFS_ROOT_ITEM_KEY || key.objectid != objectid);
3897         ret = btrfs_delete_one_dir_name(trans, root, path, di);
3898         if (ret) {
3899                 btrfs_abort_transaction(trans, root, ret);
3900                 goto out;
3901         }
3902         btrfs_release_path(path);
3903
3904         ret = btrfs_del_root_ref(trans, root->fs_info->tree_root,
3905                                  objectid, root->root_key.objectid,
3906                                  dir_ino, &index, name, name_len);
3907         if (ret < 0) {
3908                 if (ret != -ENOENT) {
3909                         btrfs_abort_transaction(trans, root, ret);
3910                         goto out;
3911                 }
3912                 di = btrfs_search_dir_index_item(root, path, dir_ino,
3913                                                  name, name_len);
3914                 if (IS_ERR_OR_NULL(di)) {
3915                         if (!di)
3916                                 ret = -ENOENT;
3917                         else
3918                                 ret = PTR_ERR(di);
3919                         btrfs_abort_transaction(trans, root, ret);
3920                         goto out;
3921                 }
3922
3923                 leaf = path->nodes[0];
3924                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3925                 btrfs_release_path(path);
3926                 index = key.offset;
3927         }
3928         btrfs_release_path(path);
3929
3930         ret = btrfs_delete_delayed_dir_index(trans, root, dir, index);
3931         if (ret) {
3932                 btrfs_abort_transaction(trans, root, ret);
3933                 goto out;
3934         }
3935
3936         btrfs_i_size_write(dir, dir->i_size - name_len * 2);
3937         inode_inc_iversion(dir);
3938         dir->i_mtime = dir->i_ctime = CURRENT_TIME;
3939         ret = btrfs_update_inode_fallback(trans, root, dir);
3940         if (ret)
3941                 btrfs_abort_transaction(trans, root, ret);
3942 out:
3943         btrfs_free_path(path);
3944         return ret;
3945 }
3946
3947 static int btrfs_rmdir(struct inode *dir, struct dentry *dentry)
3948 {
3949         struct inode *inode = dentry->d_inode;
3950         int err = 0;
3951         struct btrfs_root *root = BTRFS_I(dir)->root;
3952         struct btrfs_trans_handle *trans;
3953
3954         if (inode->i_size > BTRFS_EMPTY_DIR_SIZE)
3955                 return -ENOTEMPTY;
3956         if (btrfs_ino(inode) == BTRFS_FIRST_FREE_OBJECTID)
3957                 return -EPERM;
3958
3959         trans = __unlink_start_trans(dir);
3960         if (IS_ERR(trans))
3961                 return PTR_ERR(trans);
3962
3963         if (unlikely(btrfs_ino(inode) == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)) {
3964                 err = btrfs_unlink_subvol(trans, root, dir,
3965                                           BTRFS_I(inode)->location.objectid,
3966                                           dentry->d_name.name,
3967                                           dentry->d_name.len);
3968                 goto out;
3969         }
3970
3971         err = btrfs_orphan_add(trans, inode);
3972         if (err)
3973                 goto out;
3974
3975         /* now the directory is empty */
3976         err = btrfs_unlink_inode(trans, root, dir, dentry->d_inode,
3977                                  dentry->d_name.name, dentry->d_name.len);
3978         if (!err)
3979                 btrfs_i_size_write(inode, 0);
3980 out:
3981         btrfs_end_transaction(trans, root);
3982         btrfs_btree_balance_dirty(root);
3983
3984         return err;
3985 }
3986
3987 /*
3988  * this can truncate away extent items, csum items and directory items.
3989  * It starts at a high offset and removes keys until it can't find
3990  * any higher than new_size
3991  *
3992  * csum items that cross the new i_size are truncated to the new size
3993  * as well.
3994  *
3995  * min_type is the minimum key type to truncate down to.  If set to 0, this
3996  * will kill all the items on this inode, including the INODE_ITEM_KEY.
3997  */
3998 int btrfs_truncate_inode_items(struct btrfs_trans_handle *trans,
3999                                struct btrfs_root *root,
4000                                struct inode *inode,
4001                                u64 new_size, u32 min_type)
4002 {
4003         struct btrfs_path *path;
4004         struct extent_buffer *leaf;
4005         struct btrfs_file_extent_item *fi;
4006         struct btrfs_key key;
4007         struct btrfs_key found_key;
4008         u64 extent_start = 0;
4009         u64 extent_num_bytes = 0;
4010         u64 extent_offset = 0;
4011         u64 item_end = 0;
4012         u64 last_size = (u64)-1;
4013         u32 found_type = (u8)-1;
4014         int found_extent;
4015         int del_item;
4016         int pending_del_nr = 0;
4017         int pending_del_slot = 0;
4018         int extent_type = -1;
4019         int ret;
4020         int err = 0;
4021         u64 ino = btrfs_ino(inode);
4022
4023         BUG_ON(new_size > 0 && min_type != BTRFS_EXTENT_DATA_KEY);
4024
4025         path = btrfs_alloc_path();
4026         if (!path)
4027                 return -ENOMEM;
4028         path->reada = -1;
4029
4030         /*
4031          * We want to drop from the next block forward in case this new size is
4032          * not block aligned since we will be keeping the last block of the
4033          * extent just the way it is.
4034          */
4035         if (test_bit(BTRFS_ROOT_REF_COWS, &root->state) ||
4036             root == root->fs_info->tree_root)
4037                 btrfs_drop_extent_cache(inode, ALIGN(new_size,
4038                                         root->sectorsize), (u64)-1, 0);
4039
4040         /*
4041          * This function is also used to drop the items in the log tree before
4042          * we relog the inode, so if root != BTRFS_I(inode)->root, it means
4043          * it is used to drop the loged items. So we shouldn't kill the delayed
4044          * items.
4045          */
4046         if (min_type == 0 && root == BTRFS_I(inode)->root)
4047                 btrfs_kill_delayed_inode_items(inode);
4048
4049         key.objectid = ino;
4050         key.offset = (u64)-1;
4051         key.type = (u8)-1;
4052
4053 search_again:
4054         path->leave_spinning = 1;
4055         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
4056         if (ret < 0) {
4057                 err = ret;
4058                 goto out;
4059         }
4060
4061         if (ret > 0) {
4062                 /* there are no items in the tree for us to truncate, we're
4063                  * done
4064                  */
4065                 if (path->slots[0] == 0)
4066                         goto out;
4067                 path->slots[0]--;
4068         }
4069
4070         while (1) {
4071                 fi = NULL;
4072                 leaf = path->nodes[0];
4073                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
4074                 found_type = btrfs_key_type(&found_key);
4075
4076                 if (found_key.objectid != ino)
4077                         break;
4078
4079                 if (found_type < min_type)
4080                         break;
4081
4082                 item_end = found_key.offset;
4083                 if (found_type == BTRFS_EXTENT_DATA_KEY) {
4084                         fi = btrfs_item_ptr(leaf, path->slots[0],
4085                                             struct btrfs_file_extent_item);
4086                         extent_type = btrfs_file_extent_type(leaf, fi);
4087                         if (extent_type != BTRFS_FILE_EXTENT_INLINE) {
4088                                 item_end +=
4089                                     btrfs_file_extent_num_bytes(leaf, fi);
4090                         } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
4091                                 item_end += btrfs_file_extent_inline_len(leaf,
4092                                                          path->slots[0], fi);
4093                         }
4094                         item_end--;
4095                 }
4096                 if (found_type > min_type) {
4097                         del_item = 1;
4098                 } else {
4099                         if (item_end < new_size)
4100                                 break;
4101                         if (found_key.offset >= new_size)
4102                                 del_item = 1;
4103                         else
4104                                 del_item = 0;
4105                 }
4106                 found_extent = 0;
4107                 /* FIXME, shrink the extent if the ref count is only 1 */
4108                 if (found_type != BTRFS_EXTENT_DATA_KEY)
4109                         goto delete;
4110
4111                 if (del_item)
4112                         last_size = found_key.offset;
4113                 else
4114                         last_size = new_size;
4115
4116                 if (extent_type != BTRFS_FILE_EXTENT_INLINE) {
4117                         u64 num_dec;
4118                         extent_start = btrfs_file_extent_disk_bytenr(leaf, fi);
4119                         if (!del_item) {
4120                                 u64 orig_num_bytes =
4121                                         btrfs_file_extent_num_bytes(leaf, fi);
4122                                 extent_num_bytes = ALIGN(new_size -
4123                                                 found_key.offset,
4124                                                 root->sectorsize);
4125                                 btrfs_set_file_extent_num_bytes(leaf, fi,
4126                                                          extent_num_bytes);
4127                                 num_dec = (orig_num_bytes -
4128                                            extent_num_bytes);
4129                                 if (test_bit(BTRFS_ROOT_REF_COWS,
4130                                              &root->state) &&
4131                                     extent_start != 0)
4132                                         inode_sub_bytes(inode, num_dec);
4133                                 btrfs_mark_buffer_dirty(leaf);
4134                         } else {
4135                                 extent_num_bytes =
4136                                         btrfs_file_extent_disk_num_bytes(leaf,
4137                                                                          fi);
4138                                 extent_offset = found_key.offset -
4139                                         btrfs_file_extent_offset(leaf, fi);
4140
4141                                 /* FIXME blocksize != 4096 */
4142                                 num_dec = btrfs_file_extent_num_bytes(leaf, fi);
4143                                 if (extent_start != 0) {
4144                                         found_extent = 1;
4145                                         if (test_bit(BTRFS_ROOT_REF_COWS,
4146                                                      &root->state))
4147                                                 inode_sub_bytes(inode, num_dec);
4148                                 }
4149                         }
4150                 } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
4151                         /*
4152                          * we can't truncate inline items that have had
4153                          * special encodings
4154                          */
4155                         if (!del_item &&
4156                             btrfs_file_extent_compression(leaf, fi) == 0 &&
4157                             btrfs_file_extent_encryption(leaf, fi) == 0 &&
4158                             btrfs_file_extent_other_encoding(leaf, fi) == 0) {
4159                                 u32 size = new_size - found_key.offset;
4160
4161                                 if (test_bit(BTRFS_ROOT_REF_COWS, &root->state))
4162                                         inode_sub_bytes(inode, item_end + 1 -
4163                                                         new_size);
4164
4165                                 /*
4166                                  * update the ram bytes to properly reflect
4167                                  * the new size of our item
4168                                  */
4169                                 btrfs_set_file_extent_ram_bytes(leaf, fi, size);
4170                                 size =
4171                                     btrfs_file_extent_calc_inline_size(size);
4172                                 btrfs_truncate_item(root, path, size, 1);
4173                         } else if (test_bit(BTRFS_ROOT_REF_COWS,
4174                                             &root->state)) {
4175                                 inode_sub_bytes(inode, item_end + 1 -
4176                                                 found_key.offset);
4177                         }
4178                 }
4179 delete:
4180                 if (del_item) {
4181                         if (!pending_del_nr) {
4182                                 /* no pending yet, add ourselves */
4183                                 pending_del_slot = path->slots[0];
4184                                 pending_del_nr = 1;
4185                         } else if (pending_del_nr &&
4186                                    path->slots[0] + 1 == pending_del_slot) {
4187                                 /* hop on the pending chunk */
4188                                 pending_del_nr++;
4189                                 pending_del_slot = path->slots[0];
4190                         } else {
4191                                 BUG();
4192                         }
4193                 } else {
4194                         break;
4195                 }
4196                 if (found_extent &&
4197                     (test_bit(BTRFS_ROOT_REF_COWS, &root->state) ||
4198                      root == root->fs_info->tree_root)) {
4199                         btrfs_set_path_blocking(path);
4200                         ret = btrfs_free_extent(trans, root, extent_start,
4201                                                 extent_num_bytes, 0,
4202                                                 btrfs_header_owner(leaf),
4203                                                 ino, extent_offset, 0);
4204                         BUG_ON(ret);
4205                 }
4206
4207                 if (found_type == BTRFS_INODE_ITEM_KEY)
4208                         break;
4209
4210                 if (path->slots[0] == 0 ||
4211                     path->slots[0] != pending_del_slot) {
4212                         if (pending_del_nr) {
4213                                 ret = btrfs_del_items(trans, root, path,
4214                                                 pending_del_slot,
4215                                                 pending_del_nr);
4216                                 if (ret) {
4217                                         btrfs_abort_transaction(trans,
4218                                                                 root, ret);
4219                                         goto error;
4220                                 }
4221                                 pending_del_nr = 0;
4222                         }
4223                         btrfs_release_path(path);
4224                         goto search_again;
4225                 } else {
4226                         path->slots[0]--;
4227                 }
4228         }
4229 out:
4230         if (pending_del_nr) {
4231                 ret = btrfs_del_items(trans, root, path, pending_del_slot,
4232                                       pending_del_nr);
4233                 if (ret)
4234                         btrfs_abort_transaction(trans, root, ret);
4235         }
4236 error:
4237         if (last_size != (u64)-1)
4238                 btrfs_ordered_update_i_size(inode, last_size, NULL);
4239         btrfs_free_path(path);
4240         return err;
4241 }
4242
4243 /*
4244  * btrfs_truncate_page - read, zero a chunk and write a page
4245  * @inode - inode that we're zeroing
4246  * @from - the offset to start zeroing
4247  * @len - the length to zero, 0 to zero the entire range respective to the
4248  *      offset
4249  * @front - zero up to the offset instead of from the offset on
4250  *
4251  * This will find the page for the "from" offset and cow the page and zero the
4252  * part we want to zero.  This is used with truncate and hole punching.
4253  */
4254 int btrfs_truncate_page(struct inode *inode, loff_t from, loff_t len,
4255                         int front)
4256 {
4257         struct address_space *mapping = inode->i_mapping;
4258         struct btrfs_root *root = BTRFS_I(inode)->root;
4259         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
4260         struct btrfs_ordered_extent *ordered;
4261         struct extent_state *cached_state = NULL;
4262         char *kaddr;
4263         u32 blocksize = root->sectorsize;
4264         pgoff_t index = from >> PAGE_CACHE_SHIFT;
4265         unsigned offset = from & (PAGE_CACHE_SIZE-1);
4266         struct page *page;
4267         gfp_t mask = btrfs_alloc_write_mask(mapping);
4268         int ret = 0;
4269         u64 page_start;
4270         u64 page_end;
4271
4272         if ((offset & (blocksize - 1)) == 0 &&
4273             (!len || ((len & (blocksize - 1)) == 0)))
4274                 goto out;
4275         ret = btrfs_delalloc_reserve_space(inode, PAGE_CACHE_SIZE);
4276         if (ret)
4277                 goto out;
4278
4279 again:
4280         page = find_or_create_page(mapping, index, mask);
4281         if (!page) {
4282                 btrfs_delalloc_release_space(inode, PAGE_CACHE_SIZE);
4283                 ret = -ENOMEM;
4284                 goto out;
4285         }
4286
4287         page_start = page_offset(page);
4288         page_end = page_start + PAGE_CACHE_SIZE - 1;
4289
4290         if (!PageUptodate(page)) {
4291                 ret = btrfs_readpage(NULL, page);
4292                 lock_page(page);
4293                 if (page->mapping != mapping) {
4294                         unlock_page(page);
4295                         page_cache_release(page);
4296                         goto again;
4297                 }
4298                 if (!PageUptodate(page)) {
4299                         ret = -EIO;
4300                         goto out_unlock;
4301                 }
4302         }
4303         wait_on_page_writeback(page);
4304
4305         lock_extent_bits(io_tree, page_start, page_end, 0, &cached_state);
4306         set_page_extent_mapped(page);
4307
4308         ordered = btrfs_lookup_ordered_extent(inode, page_start);
4309         if (ordered) {
4310                 unlock_extent_cached(io_tree, page_start, page_end,
4311                                      &cached_state, GFP_NOFS);
4312                 unlock_page(page);
4313                 page_cache_release(page);
4314                 btrfs_start_ordered_extent(inode, ordered, 1);
4315                 btrfs_put_ordered_extent(ordered);
4316                 goto again;
4317         }
4318
4319         clear_extent_bit(&BTRFS_I(inode)->io_tree, page_start, page_end,
4320                           EXTENT_DIRTY | EXTENT_DELALLOC |
4321                           EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG,
4322                           0, 0, &cached_state, GFP_NOFS);
4323
4324         ret = btrfs_set_extent_delalloc(inode, page_start, page_end,
4325                                         &cached_state);
4326         if (ret) {
4327                 unlock_extent_cached(io_tree, page_start, page_end,
4328                                      &cached_state, GFP_NOFS);
4329                 goto out_unlock;
4330         }
4331
4332         if (offset != PAGE_CACHE_SIZE) {
4333                 if (!len)
4334                         len = PAGE_CACHE_SIZE - offset;
4335                 kaddr = kmap(page);
4336                 if (front)
4337                         memset(kaddr, 0, offset);
4338                 else
4339                         memset(kaddr + offset, 0, len);
4340                 flush_dcache_page(page);
4341                 kunmap(page);
4342         }
4343         ClearPageChecked(page);
4344         set_page_dirty(page);
4345         unlock_extent_cached(io_tree, page_start, page_end, &cached_state,
4346                              GFP_NOFS);
4347
4348 out_unlock:
4349         if (ret)
4350                 btrfs_delalloc_release_space(inode, PAGE_CACHE_SIZE);
4351         unlock_page(page);
4352         page_cache_release(page);
4353 out:
4354         return ret;
4355 }
4356
4357 static int maybe_insert_hole(struct btrfs_root *root, struct inode *inode,
4358                              u64 offset, u64 len)
4359 {
4360         struct btrfs_trans_handle *trans;
4361         int ret;
4362
4363         /*
4364          * Still need to make sure the inode looks like it's been updated so
4365          * that any holes get logged if we fsync.
4366          */
4367         if (btrfs_fs_incompat(root->fs_info, NO_HOLES)) {
4368                 BTRFS_I(inode)->last_trans = root->fs_info->generation;
4369                 BTRFS_I(inode)->last_sub_trans = root->log_transid;
4370                 BTRFS_I(inode)->last_log_commit = root->last_log_commit;
4371                 return 0;
4372         }
4373
4374         /*
4375          * 1 - for the one we're dropping
4376          * 1 - for the one we're adding
4377          * 1 - for updating the inode.
4378          */
4379         trans = btrfs_start_transaction(root, 3);
4380         if (IS_ERR(trans))
4381                 return PTR_ERR(trans);
4382
4383         ret = btrfs_drop_extents(trans, root, inode, offset, offset + len, 1);
4384         if (ret) {
4385                 btrfs_abort_transaction(trans, root, ret);
4386                 btrfs_end_transaction(trans, root);
4387                 return ret;
4388         }
4389
4390         ret = btrfs_insert_file_extent(trans, root, btrfs_ino(inode), offset,
4391                                        0, 0, len, 0, len, 0, 0, 0);
4392         if (ret)
4393                 btrfs_abort_transaction(trans, root, ret);
4394         else
4395                 btrfs_update_inode(trans, root, inode);
4396         btrfs_end_transaction(trans, root);
4397         return ret;
4398 }
4399
4400 /*
4401  * This function puts in dummy file extents for the area we're creating a hole
4402  * for.  So if we are truncating this file to a larger size we need to insert
4403  * these file extents so that btrfs_get_extent will return a EXTENT_MAP_HOLE for
4404  * the range between oldsize and size
4405  */
4406 int btrfs_cont_expand(struct inode *inode, loff_t oldsize, loff_t size)
4407 {
4408         struct btrfs_root *root = BTRFS_I(inode)->root;
4409         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
4410         struct extent_map *em = NULL;
4411         struct extent_state *cached_state = NULL;
4412         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
4413         u64 hole_start = ALIGN(oldsize, root->sectorsize);
4414         u64 block_end = ALIGN(size, root->sectorsize);
4415         u64 last_byte;
4416         u64 cur_offset;
4417         u64 hole_size;
4418         int err = 0;
4419
4420         /*
4421          * If our size started in the middle of a page we need to zero out the
4422          * rest of the page before we expand the i_size, otherwise we could
4423          * expose stale data.
4424          */
4425         err = btrfs_truncate_page(inode, oldsize, 0, 0);
4426         if (err)
4427                 return err;
4428
4429         if (size <= hole_start)
4430                 return 0;
4431
4432         while (1) {
4433                 struct btrfs_ordered_extent *ordered;
4434
4435                 lock_extent_bits(io_tree, hole_start, block_end - 1, 0,
4436                                  &cached_state);
4437                 ordered = btrfs_lookup_ordered_range(inode, hole_start,
4438                                                      block_end - hole_start);
4439                 if (!ordered)
4440                         break;
4441                 unlock_extent_cached(io_tree, hole_start, block_end - 1,
4442                                      &cached_state, GFP_NOFS);
4443                 btrfs_start_ordered_extent(inode, ordered, 1);
4444                 btrfs_put_ordered_extent(ordered);
4445         }
4446
4447         cur_offset = hole_start;
4448         while (1) {
4449                 em = btrfs_get_extent(inode, NULL, 0, cur_offset,
4450                                 block_end - cur_offset, 0);
4451                 if (IS_ERR(em)) {
4452                         err = PTR_ERR(em);
4453                         em = NULL;
4454                         break;
4455                 }
4456                 last_byte = min(extent_map_end(em), block_end);
4457                 last_byte = ALIGN(last_byte , root->sectorsize);
4458                 if (!test_bit(EXTENT_FLAG_PREALLOC, &em->flags)) {
4459                         struct extent_map *hole_em;
4460                         hole_size = last_byte - cur_offset;
4461
4462                         err = maybe_insert_hole(root, inode, cur_offset,
4463                                                 hole_size);
4464                         if (err)
4465                                 break;
4466                         btrfs_drop_extent_cache(inode, cur_offset,
4467                                                 cur_offset + hole_size - 1, 0);
4468                         hole_em = alloc_extent_map();
4469                         if (!hole_em) {
4470                                 set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
4471                                         &BTRFS_I(inode)->runtime_flags);
4472                                 goto next;
4473                         }
4474                         hole_em->start = cur_offset;
4475                         hole_em->len = hole_size;
4476                         hole_em->orig_start = cur_offset;
4477
4478                         hole_em->block_start = EXTENT_MAP_HOLE;
4479                         hole_em->block_len = 0;
4480                         hole_em->orig_block_len = 0;
4481                         hole_em->ram_bytes = hole_size;
4482                         hole_em->bdev = root->fs_info->fs_devices->latest_bdev;
4483                         hole_em->compress_type = BTRFS_COMPRESS_NONE;
4484                         hole_em->generation = root->fs_info->generation;
4485
4486                         while (1) {
4487                                 write_lock(&em_tree->lock);
4488                                 err = add_extent_mapping(em_tree, hole_em, 1);
4489                                 write_unlock(&em_tree->lock);
4490                                 if (err != -EEXIST)
4491                                         break;
4492                                 btrfs_drop_extent_cache(inode, cur_offset,
4493                                                         cur_offset +
4494                                                         hole_size - 1, 0);
4495                         }
4496                         free_extent_map(hole_em);
4497                 }
4498 next:
4499                 free_extent_map(em);
4500                 em = NULL;
4501                 cur_offset = last_byte;
4502                 if (cur_offset >= block_end)
4503                         break;
4504         }
4505         free_extent_map(em);
4506         unlock_extent_cached(io_tree, hole_start, block_end - 1, &cached_state,
4507                              GFP_NOFS);
4508         return err;
4509 }
4510
4511 static int btrfs_setsize(struct inode *inode, struct iattr *attr)
4512 {
4513         struct btrfs_root *root = BTRFS_I(inode)->root;
4514         struct btrfs_trans_handle *trans;
4515         loff_t oldsize = i_size_read(inode);
4516         loff_t newsize = attr->ia_size;
4517         int mask = attr->ia_valid;
4518         int ret;
4519
4520         /*
4521          * The regular truncate() case without ATTR_CTIME and ATTR_MTIME is a
4522          * special case where we need to update the times despite not having
4523          * these flags set.  For all other operations the VFS set these flags
4524          * explicitly if it wants a timestamp update.
4525          */
4526         if (newsize != oldsize) {
4527                 inode_inc_iversion(inode);
4528                 if (!(mask & (ATTR_CTIME | ATTR_MTIME)))
4529                         inode->i_ctime = inode->i_mtime =
4530                                 current_fs_time(inode->i_sb);
4531         }
4532
4533         if (newsize > oldsize) {
4534                 truncate_pagecache(inode, newsize);
4535                 ret = btrfs_cont_expand(inode, oldsize, newsize);
4536                 if (ret)
4537                         return ret;
4538
4539                 trans = btrfs_start_transaction(root, 1);
4540                 if (IS_ERR(trans))
4541                         return PTR_ERR(trans);
4542
4543                 i_size_write(inode, newsize);
4544                 btrfs_ordered_update_i_size(inode, i_size_read(inode), NULL);
4545                 ret = btrfs_update_inode(trans, root, inode);
4546                 btrfs_end_transaction(trans, root);
4547         } else {
4548
4549                 /*
4550                  * We're truncating a file that used to have good data down to
4551                  * zero. Make sure it gets into the ordered flush list so that
4552                  * any new writes get down to disk quickly.
4553                  */
4554                 if (newsize == 0)
4555                         set_bit(BTRFS_INODE_ORDERED_DATA_CLOSE,
4556                                 &BTRFS_I(inode)->runtime_flags);
4557
4558                 /*
4559                  * 1 for the orphan item we're going to add
4560                  * 1 for the orphan item deletion.
4561                  */
4562                 trans = btrfs_start_transaction(root, 2);
4563                 if (IS_ERR(trans))
4564                         return PTR_ERR(trans);
4565
4566                 /*
4567                  * We need to do this in case we fail at _any_ point during the
4568                  * actual truncate.  Once we do the truncate_setsize we could
4569                  * invalidate pages which forces any outstanding ordered io to
4570                  * be instantly completed which will give us extents that need
4571                  * to be truncated.  If we fail to get an orphan inode down we
4572                  * could have left over extents that were never meant to live,
4573                  * so we need to garuntee from this point on that everything
4574                  * will be consistent.
4575                  */
4576                 ret = btrfs_orphan_add(trans, inode);
4577                 btrfs_end_transaction(trans, root);
4578                 if (ret)
4579                         return ret;
4580
4581                 /* we don't support swapfiles, so vmtruncate shouldn't fail */
4582                 truncate_setsize(inode, newsize);
4583
4584                 /* Disable nonlocked read DIO to avoid the end less truncate */
4585                 btrfs_inode_block_unlocked_dio(inode);
4586                 inode_dio_wait(inode);
4587                 btrfs_inode_resume_unlocked_dio(inode);
4588
4589                 ret = btrfs_truncate(inode);
4590                 if (ret && inode->i_nlink) {
4591                         int err;
4592
4593                         /*
4594                          * failed to truncate, disk_i_size is only adjusted down
4595                          * as we remove extents, so it should represent the true
4596                          * size of the inode, so reset the in memory size and
4597                          * delete our orphan entry.
4598                          */
4599                         trans = btrfs_join_transaction(root);
4600                         if (IS_ERR(trans)) {
4601                                 btrfs_orphan_del(NULL, inode);
4602                                 return ret;
4603                         }
4604                         i_size_write(inode, BTRFS_I(inode)->disk_i_size);
4605                         err = btrfs_orphan_del(trans, inode);
4606                         if (err)
4607                                 btrfs_abort_transaction(trans, root, err);
4608                         btrfs_end_transaction(trans, root);
4609                 }
4610         }
4611
4612         return ret;
4613 }
4614
4615 static int btrfs_setattr(struct dentry *dentry, struct iattr *attr)
4616 {
4617         struct inode *inode = dentry->d_inode;
4618         struct btrfs_root *root = BTRFS_I(inode)->root;
4619         int err;
4620
4621         if (btrfs_root_readonly(root))
4622                 return -EROFS;
4623
4624         err = inode_change_ok(inode, attr);
4625         if (err)
4626                 return err;
4627
4628         if (S_ISREG(inode->i_mode) && (attr->ia_valid & ATTR_SIZE)) {
4629                 err = btrfs_setsize(inode, attr);
4630                 if (err)
4631                         return err;
4632         }
4633
4634         if (attr->ia_valid) {
4635                 setattr_copy(inode, attr);
4636                 inode_inc_iversion(inode);
4637                 err = btrfs_dirty_inode(inode);
4638
4639                 if (!err && attr->ia_valid & ATTR_MODE)
4640                         err = posix_acl_chmod(inode, inode->i_mode);
4641         }
4642
4643         return err;
4644 }
4645
4646 /*
4647  * While truncating the inode pages during eviction, we get the VFS calling
4648  * btrfs_invalidatepage() against each page of the inode. This is slow because
4649  * the calls to btrfs_invalidatepage() result in a huge amount of calls to
4650  * lock_extent_bits() and clear_extent_bit(), which keep merging and splitting
4651  * extent_state structures over and over, wasting lots of time.
4652  *
4653  * Therefore if the inode is being evicted, let btrfs_invalidatepage() skip all
4654  * those expensive operations on a per page basis and do only the ordered io
4655  * finishing, while we release here the extent_map and extent_state structures,
4656  * without the excessive merging and splitting.
4657  */
4658 static void evict_inode_truncate_pages(struct inode *inode)
4659 {
4660         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
4661         struct extent_map_tree *map_tree = &BTRFS_I(inode)->extent_tree;
4662         struct rb_node *node;
4663
4664         ASSERT(inode->i_state & I_FREEING);
4665         truncate_inode_pages_final(&inode->i_data);
4666
4667         write_lock(&map_tree->lock);
4668         while (!RB_EMPTY_ROOT(&map_tree->map)) {
4669                 struct extent_map *em;
4670
4671                 node = rb_first(&map_tree->map);
4672                 em = rb_entry(node, struct extent_map, rb_node);
4673                 clear_bit(EXTENT_FLAG_PINNED, &em->flags);
4674                 clear_bit(EXTENT_FLAG_LOGGING, &em->flags);
4675                 remove_extent_mapping(map_tree, em);
4676                 free_extent_map(em);
4677         }
4678         write_unlock(&map_tree->lock);
4679
4680         spin_lock(&io_tree->lock);
4681         while (!RB_EMPTY_ROOT(&io_tree->state)) {
4682                 struct extent_state *state;
4683                 struct extent_state *cached_state = NULL;
4684
4685                 node = rb_first(&io_tree->state);
4686                 state = rb_entry(node, struct extent_state, rb_node);
4687                 atomic_inc(&state->refs);
4688                 spin_unlock(&io_tree->lock);
4689
4690                 lock_extent_bits(io_tree, state->start, state->end,
4691                                  0, &cached_state);
4692                 clear_extent_bit(io_tree, state->start, state->end,
4693                                  EXTENT_LOCKED | EXTENT_DIRTY |
4694                                  EXTENT_DELALLOC | EXTENT_DO_ACCOUNTING |
4695                                  EXTENT_DEFRAG, 1, 1,
4696                                  &cached_state, GFP_NOFS);
4697                 free_extent_state(state);
4698
4699                 spin_lock(&io_tree->lock);
4700         }
4701         spin_unlock(&io_tree->lock);
4702 }
4703
4704 void btrfs_evict_inode(struct inode *inode)
4705 {
4706         struct btrfs_trans_handle *trans;
4707         struct btrfs_root *root = BTRFS_I(inode)->root;
4708         struct btrfs_block_rsv *rsv, *global_rsv;
4709         u64 min_size = btrfs_calc_trunc_metadata_size(root, 1);
4710         int ret;
4711
4712         trace_btrfs_inode_evict(inode);
4713
4714         evict_inode_truncate_pages(inode);
4715
4716         if (inode->i_nlink &&
4717             ((btrfs_root_refs(&root->root_item) != 0 &&
4718               root->root_key.objectid != BTRFS_ROOT_TREE_OBJECTID) ||
4719              btrfs_is_free_space_inode(inode)))
4720                 goto no_delete;
4721
4722         if (is_bad_inode(inode)) {
4723                 btrfs_orphan_del(NULL, inode);
4724                 goto no_delete;
4725         }
4726         /* do we really want it for ->i_nlink > 0 and zero btrfs_root_refs? */
4727         btrfs_wait_ordered_range(inode, 0, (u64)-1);
4728
4729         if (root->fs_info->log_root_recovering) {
4730                 BUG_ON(test_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
4731                                  &BTRFS_I(inode)->runtime_flags));
4732                 goto no_delete;
4733         }
4734
4735         if (inode->i_nlink > 0) {
4736                 BUG_ON(btrfs_root_refs(&root->root_item) != 0 &&
4737                        root->root_key.objectid != BTRFS_ROOT_TREE_OBJECTID);
4738                 goto no_delete;
4739         }
4740
4741         ret = btrfs_commit_inode_delayed_inode(inode);
4742         if (ret) {
4743                 btrfs_orphan_del(NULL, inode);
4744                 goto no_delete;
4745         }
4746
4747         rsv = btrfs_alloc_block_rsv(root, BTRFS_BLOCK_RSV_TEMP);
4748         if (!rsv) {
4749                 btrfs_orphan_del(NULL, inode);
4750                 goto no_delete;
4751         }
4752         rsv->size = min_size;
4753         rsv->failfast = 1;
4754         global_rsv = &root->fs_info->global_block_rsv;
4755
4756         btrfs_i_size_write(inode, 0);
4757
4758         /*
4759          * This is a bit simpler than btrfs_truncate since we've already
4760          * reserved our space for our orphan item in the unlink, so we just
4761          * need to reserve some slack space in case we add bytes and update
4762          * inode item when doing the truncate.
4763          */
4764         while (1) {
4765                 ret = btrfs_block_rsv_refill(root, rsv, min_size,
4766                                              BTRFS_RESERVE_FLUSH_LIMIT);
4767
4768                 /*
4769                  * Try and steal from the global reserve since we will
4770                  * likely not use this space anyway, we want to try as
4771                  * hard as possible to get this to work.
4772                  */
4773                 if (ret)
4774                         ret = btrfs_block_rsv_migrate(global_rsv, rsv, min_size);
4775
4776                 if (ret) {
4777                         btrfs_warn(root->fs_info,
4778                                 "Could not get space for a delete, will truncate on mount %d",
4779                                 ret);
4780                         btrfs_orphan_del(NULL, inode);
4781                         btrfs_free_block_rsv(root, rsv);
4782                         goto no_delete;
4783                 }
4784
4785                 trans = btrfs_join_transaction(root);
4786                 if (IS_ERR(trans)) {
4787                         btrfs_orphan_del(NULL, inode);
4788                         btrfs_free_block_rsv(root, rsv);
4789                         goto no_delete;
4790                 }
4791
4792                 trans->block_rsv = rsv;
4793
4794                 ret = btrfs_truncate_inode_items(trans, root, inode, 0, 0);
4795                 if (ret != -ENOSPC)
4796                         break;
4797
4798                 trans->block_rsv = &root->fs_info->trans_block_rsv;
4799                 btrfs_end_transaction(trans, root);
4800                 trans = NULL;
4801                 btrfs_btree_balance_dirty(root);
4802         }
4803
4804         btrfs_free_block_rsv(root, rsv);
4805
4806         /*
4807          * Errors here aren't a big deal, it just means we leave orphan items
4808          * in the tree.  They will be cleaned up on the next mount.
4809          */
4810         if (ret == 0) {
4811                 trans->block_rsv = root->orphan_block_rsv;
4812                 btrfs_orphan_del(trans, inode);
4813         } else {
4814                 btrfs_orphan_del(NULL, inode);
4815         }
4816
4817         trans->block_rsv = &root->fs_info->trans_block_rsv;
4818         if (!(root == root->fs_info->tree_root ||
4819               root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID))
4820                 btrfs_return_ino(root, btrfs_ino(inode));
4821
4822         btrfs_end_transaction(trans, root);
4823         btrfs_btree_balance_dirty(root);
4824 no_delete:
4825         btrfs_remove_delayed_node(inode);
4826         clear_inode(inode);
4827         return;
4828 }
4829
4830 /*
4831  * this returns the key found in the dir entry in the location pointer.
4832  * If no dir entries were found, location->objectid is 0.
4833  */
4834 static int btrfs_inode_by_name(struct inode *dir, struct dentry *dentry,
4835                                struct btrfs_key *location)
4836 {
4837         const char *name = dentry->d_name.name;
4838         int namelen = dentry->d_name.len;
4839         struct btrfs_dir_item *di;
4840         struct btrfs_path *path;
4841         struct btrfs_root *root = BTRFS_I(dir)->root;
4842         int ret = 0;
4843
4844         path = btrfs_alloc_path();
4845         if (!path)
4846                 return -ENOMEM;
4847
4848         di = btrfs_lookup_dir_item(NULL, root, path, btrfs_ino(dir), name,
4849                                     namelen, 0);
4850         if (IS_ERR(di))
4851                 ret = PTR_ERR(di);
4852
4853         if (IS_ERR_OR_NULL(di))
4854                 goto out_err;
4855
4856         btrfs_dir_item_key_to_cpu(path->nodes[0], di, location);
4857 out:
4858         btrfs_free_path(path);
4859         return ret;
4860 out_err:
4861         location->objectid = 0;
4862         goto out;
4863 }
4864
4865 /*
4866  * when we hit a tree root in a directory, the btrfs part of the inode
4867  * needs to be changed to reflect the root directory of the tree root.  This
4868  * is kind of like crossing a mount point.
4869  */
4870 static int fixup_tree_root_location(struct btrfs_root *root,
4871                                     struct inode *dir,
4872                                     struct dentry *dentry,
4873                                     struct btrfs_key *location,
4874                                     struct btrfs_root **sub_root)
4875 {
4876         struct btrfs_path *path;
4877         struct btrfs_root *new_root;
4878         struct btrfs_root_ref *ref;
4879         struct extent_buffer *leaf;
4880         int ret;
4881         int err = 0;
4882
4883         path = btrfs_alloc_path();
4884         if (!path) {
4885                 err = -ENOMEM;
4886                 goto out;
4887         }
4888
4889         err = -ENOENT;
4890         ret = btrfs_find_item(root->fs_info->tree_root, path,
4891                                 BTRFS_I(dir)->root->root_key.objectid,
4892                                 location->objectid, BTRFS_ROOT_REF_KEY, NULL);
4893         if (ret) {
4894                 if (ret < 0)
4895                         err = ret;
4896                 goto out;
4897         }
4898
4899         leaf = path->nodes[0];
4900         ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_ref);
4901         if (btrfs_root_ref_dirid(leaf, ref) != btrfs_ino(dir) ||
4902             btrfs_root_ref_name_len(leaf, ref) != dentry->d_name.len)
4903                 goto out;
4904
4905         ret = memcmp_extent_buffer(leaf, dentry->d_name.name,
4906                                    (unsigned long)(ref + 1),
4907                                    dentry->d_name.len);
4908         if (ret)
4909                 goto out;
4910
4911         btrfs_release_path(path);
4912
4913         new_root = btrfs_read_fs_root_no_name(root->fs_info, location);
4914         if (IS_ERR(new_root)) {
4915                 err = PTR_ERR(new_root);
4916                 goto out;
4917         }
4918
4919         *sub_root = new_root;
4920         location->objectid = btrfs_root_dirid(&new_root->root_item);
4921         location->type = BTRFS_INODE_ITEM_KEY;
4922         location->offset = 0;
4923         err = 0;
4924 out:
4925         btrfs_free_path(path);
4926         return err;
4927 }
4928
4929 static void inode_tree_add(struct inode *inode)
4930 {
4931         struct btrfs_root *root = BTRFS_I(inode)->root;
4932         struct btrfs_inode *entry;
4933         struct rb_node **p;
4934         struct rb_node *parent;
4935         struct rb_node *new = &BTRFS_I(inode)->rb_node;
4936         u64 ino = btrfs_ino(inode);
4937
4938         if (inode_unhashed(inode))
4939                 return;
4940         parent = NULL;
4941         spin_lock(&root->inode_lock);
4942         p = &root->inode_tree.rb_node;
4943         while (*p) {
4944                 parent = *p;
4945                 entry = rb_entry(parent, struct btrfs_inode, rb_node);
4946
4947                 if (ino < btrfs_ino(&entry->vfs_inode))
4948                         p = &parent->rb_left;
4949                 else if (ino > btrfs_ino(&entry->vfs_inode))
4950                         p = &parent->rb_right;
4951                 else {
4952                         WARN_ON(!(entry->vfs_inode.i_state &
4953                                   (I_WILL_FREE | I_FREEING)));
4954                         rb_replace_node(parent, new, &root->inode_tree);
4955                         RB_CLEAR_NODE(parent);
4956                         spin_unlock(&root->inode_lock);
4957                         return;
4958                 }
4959         }
4960         rb_link_node(new, parent, p);
4961         rb_insert_color(new, &root->inode_tree);
4962         spin_unlock(&root->inode_lock);
4963 }
4964
4965 static void inode_tree_del(struct inode *inode)
4966 {
4967         struct btrfs_root *root = BTRFS_I(inode)->root;
4968         int empty = 0;
4969
4970         spin_lock(&root->inode_lock);
4971         if (!RB_EMPTY_NODE(&BTRFS_I(inode)->rb_node)) {
4972                 rb_erase(&BTRFS_I(inode)->rb_node, &root->inode_tree);
4973                 RB_CLEAR_NODE(&BTRFS_I(inode)->rb_node);
4974                 empty = RB_EMPTY_ROOT(&root->inode_tree);
4975         }
4976         spin_unlock(&root->inode_lock);
4977
4978         if (empty && btrfs_root_refs(&root->root_item) == 0) {
4979                 synchronize_srcu(&root->fs_info->subvol_srcu);
4980                 spin_lock(&root->inode_lock);
4981                 empty = RB_EMPTY_ROOT(&root->inode_tree);
4982                 spin_unlock(&root->inode_lock);
4983                 if (empty)
4984                         btrfs_add_dead_root(root);
4985         }
4986 }
4987
4988 void btrfs_invalidate_inodes(struct btrfs_root *root)
4989 {
4990         struct rb_node *node;
4991         struct rb_node *prev;
4992         struct btrfs_inode *entry;
4993         struct inode *inode;
4994         u64 objectid = 0;
4995
4996         if (!test_bit(BTRFS_FS_STATE_ERROR, &root->fs_info->fs_state))
4997                 WARN_ON(btrfs_root_refs(&root->root_item) != 0);
4998
4999         spin_lock(&root->inode_lock);
5000 again:
5001         node = root->inode_tree.rb_node;
5002         prev = NULL;
5003         while (node) {
5004                 prev = node;
5005                 entry = rb_entry(node, struct btrfs_inode, rb_node);
5006
5007                 if (objectid < btrfs_ino(&entry->vfs_inode))
5008                         node = node->rb_left;
5009                 else if (objectid > btrfs_ino(&entry->vfs_inode))
5010                         node = node->rb_right;
5011                 else
5012                         break;
5013         }
5014         if (!node) {
5015                 while (prev) {
5016                         entry = rb_entry(prev, struct btrfs_inode, rb_node);
5017                         if (objectid <= btrfs_ino(&entry->vfs_inode)) {
5018                                 node = prev;
5019                                 break;
5020                         }
5021                         prev = rb_next(prev);
5022                 }
5023         }
5024         while (node) {
5025                 entry = rb_entry(node, struct btrfs_inode, rb_node);
5026                 objectid = btrfs_ino(&entry->vfs_inode) + 1;
5027                 inode = igrab(&entry->vfs_inode);
5028                 if (inode) {
5029                         spin_unlock(&root->inode_lock);
5030                         if (atomic_read(&inode->i_count) > 1)
5031                                 d_prune_aliases(inode);
5032                         /*
5033                          * btrfs_drop_inode will have it removed from
5034                          * the inode cache when its usage count
5035                          * hits zero.
5036                          */
5037                         iput(inode);
5038                         cond_resched();
5039                         spin_lock(&root->inode_lock);
5040                         goto again;
5041                 }
5042
5043                 if (cond_resched_lock(&root->inode_lock))
5044                         goto again;
5045
5046                 node = rb_next(node);
5047         }
5048         spin_unlock(&root->inode_lock);
5049 }
5050
5051 static int btrfs_init_locked_inode(struct inode *inode, void *p)
5052 {
5053         struct btrfs_iget_args *args = p;
5054         inode->i_ino = args->location->objectid;
5055         memcpy(&BTRFS_I(inode)->location, args->location,
5056                sizeof(*args->location));
5057         BTRFS_I(inode)->root = args->root;
5058         return 0;
5059 }
5060
5061 static int btrfs_find_actor(struct inode *inode, void *opaque)
5062 {
5063         struct btrfs_iget_args *args = opaque;
5064         return args->location->objectid == BTRFS_I(inode)->location.objectid &&
5065                 args->root == BTRFS_I(inode)->root;
5066 }
5067
5068 static struct inode *btrfs_iget_locked(struct super_block *s,
5069                                        struct btrfs_key *location,
5070                                        struct btrfs_root *root)
5071 {
5072         struct inode *inode;
5073         struct btrfs_iget_args args;
5074         unsigned long hashval = btrfs_inode_hash(location->objectid, root);
5075
5076         args.location = location;
5077         args.root = root;
5078
5079         inode = iget5_locked(s, hashval, btrfs_find_actor,
5080                              btrfs_init_locked_inode,
5081                              (void *)&args);
5082         return inode;
5083 }
5084
5085 /* Get an inode object given its location and corresponding root.
5086  * Returns in *is_new if the inode was read from disk
5087  */
5088 struct inode *btrfs_iget(struct super_block *s, struct btrfs_key *location,
5089                          struct btrfs_root *root, int *new)
5090 {
5091         struct inode *inode;
5092
5093         inode = btrfs_iget_locked(s, location, root);
5094         if (!inode)
5095                 return ERR_PTR(-ENOMEM);
5096
5097         if (inode->i_state & I_NEW) {
5098                 btrfs_read_locked_inode(inode);
5099                 if (!is_bad_inode(inode)) {
5100                         inode_tree_add(inode);
5101                         unlock_new_inode(inode);
5102                         if (new)
5103                                 *new = 1;
5104                 } else {
5105                         unlock_new_inode(inode);
5106                         iput(inode);
5107                         inode = ERR_PTR(-ESTALE);
5108                 }
5109         }
5110
5111         return inode;
5112 }
5113
5114 static struct inode *new_simple_dir(struct super_block *s,
5115                                     struct btrfs_key *key,
5116                                     struct btrfs_root *root)
5117 {
5118         struct inode *inode = new_inode(s);
5119
5120         if (!inode)
5121                 return ERR_PTR(-ENOMEM);
5122
5123         BTRFS_I(inode)->root = root;
5124         memcpy(&BTRFS_I(inode)->location, key, sizeof(*key));
5125         set_bit(BTRFS_INODE_DUMMY, &BTRFS_I(inode)->runtime_flags);
5126
5127         inode->i_ino = BTRFS_EMPTY_SUBVOL_DIR_OBJECTID;
5128         inode->i_op = &btrfs_dir_ro_inode_operations;
5129         inode->i_fop = &simple_dir_operations;
5130         inode->i_mode = S_IFDIR | S_IRUGO | S_IWUSR | S_IXUGO;
5131         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
5132
5133         return inode;
5134 }
5135
5136 struct inode *btrfs_lookup_dentry(struct inode *dir, struct dentry *dentry)
5137 {
5138         struct inode *inode;
5139         struct btrfs_root *root = BTRFS_I(dir)->root;
5140         struct btrfs_root *sub_root = root;
5141         struct btrfs_key location;
5142         int index;
5143         int ret = 0;
5144
5145         if (dentry->d_name.len > BTRFS_NAME_LEN)
5146                 return ERR_PTR(-ENAMETOOLONG);
5147
5148         ret = btrfs_inode_by_name(dir, dentry, &location);
5149         if (ret < 0)
5150                 return ERR_PTR(ret);
5151
5152         if (location.objectid == 0)
5153                 return ERR_PTR(-ENOENT);
5154
5155         if (location.type == BTRFS_INODE_ITEM_KEY) {
5156                 inode = btrfs_iget(dir->i_sb, &location, root, NULL);
5157                 return inode;
5158         }
5159
5160         BUG_ON(location.type != BTRFS_ROOT_ITEM_KEY);
5161
5162         index = srcu_read_lock(&root->fs_info->subvol_srcu);
5163         ret = fixup_tree_root_location(root, dir, dentry,
5164                                        &location, &sub_root);
5165         if (ret < 0) {
5166                 if (ret != -ENOENT)
5167                         inode = ERR_PTR(ret);
5168                 else
5169                         inode = new_simple_dir(dir->i_sb, &location, sub_root);
5170         } else {
5171                 inode = btrfs_iget(dir->i_sb, &location, sub_root, NULL);
5172         }
5173         srcu_read_unlock(&root->fs_info->subvol_srcu, index);
5174
5175         if (!IS_ERR(inode) && root != sub_root) {
5176                 down_read(&root->fs_info->cleanup_work_sem);
5177                 if (!(inode->i_sb->s_flags & MS_RDONLY))
5178                         ret = btrfs_orphan_cleanup(sub_root);
5179                 up_read(&root->fs_info->cleanup_work_sem);
5180                 if (ret) {
5181                         iput(inode);
5182                         inode = ERR_PTR(ret);
5183                 }
5184         }
5185
5186         return inode;
5187 }
5188
5189 static int btrfs_dentry_delete(const struct dentry *dentry)
5190 {
5191         struct btrfs_root *root;
5192         struct inode *inode = dentry->d_inode;
5193
5194         if (!inode && !IS_ROOT(dentry))
5195                 inode = dentry->d_parent->d_inode;
5196
5197         if (inode) {
5198                 root = BTRFS_I(inode)->root;
5199                 if (btrfs_root_refs(&root->root_item) == 0)
5200                         return 1;
5201
5202                 if (btrfs_ino(inode) == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)
5203                         return 1;
5204         }
5205         return 0;
5206 }
5207
5208 static void btrfs_dentry_release(struct dentry *dentry)
5209 {
5210         kfree(dentry->d_fsdata);
5211 }
5212
5213 static struct dentry *btrfs_lookup(struct inode *dir, struct dentry *dentry,
5214                                    unsigned int flags)
5215 {
5216         struct inode *inode;
5217
5218         inode = btrfs_lookup_dentry(dir, dentry);
5219         if (IS_ERR(inode)) {
5220                 if (PTR_ERR(inode) == -ENOENT)
5221                         inode = NULL;
5222                 else
5223                         return ERR_CAST(inode);
5224         }
5225
5226         return d_materialise_unique(dentry, inode);
5227 }
5228
5229 unsigned char btrfs_filetype_table[] = {
5230         DT_UNKNOWN, DT_REG, DT_DIR, DT_CHR, DT_BLK, DT_FIFO, DT_SOCK, DT_LNK
5231 };
5232
5233 static int btrfs_real_readdir(struct file *file, struct dir_context *ctx)
5234 {
5235         struct inode *inode = file_inode(file);
5236         struct btrfs_root *root = BTRFS_I(inode)->root;
5237         struct btrfs_item *item;
5238         struct btrfs_dir_item *di;
5239         struct btrfs_key key;
5240         struct btrfs_key found_key;
5241         struct btrfs_path *path;
5242         struct list_head ins_list;
5243         struct list_head del_list;
5244         int ret;
5245         struct extent_buffer *leaf;
5246         int slot;
5247         unsigned char d_type;
5248         int over = 0;
5249         u32 di_cur;
5250         u32 di_total;
5251         u32 di_len;
5252         int key_type = BTRFS_DIR_INDEX_KEY;
5253         char tmp_name[32];
5254         char *name_ptr;
5255         int name_len;
5256         int is_curr = 0;        /* ctx->pos points to the current index? */
5257
5258         /* FIXME, use a real flag for deciding about the key type */
5259         if (root->fs_info->tree_root == root)
5260                 key_type = BTRFS_DIR_ITEM_KEY;
5261
5262         if (!dir_emit_dots(file, ctx))
5263                 return 0;
5264
5265         path = btrfs_alloc_path();
5266         if (!path)
5267                 return -ENOMEM;
5268
5269         path->reada = 1;
5270
5271         if (key_type == BTRFS_DIR_INDEX_KEY) {
5272                 INIT_LIST_HEAD(&ins_list);
5273                 INIT_LIST_HEAD(&del_list);
5274                 btrfs_get_delayed_items(inode, &ins_list, &del_list);
5275         }
5276
5277         btrfs_set_key_type(&key, key_type);
5278         key.offset = ctx->pos;
5279         key.objectid = btrfs_ino(inode);
5280
5281         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
5282         if (ret < 0)
5283                 goto err;
5284
5285         while (1) {
5286                 leaf = path->nodes[0];
5287                 slot = path->slots[0];
5288                 if (slot >= btrfs_header_nritems(leaf)) {
5289                         ret = btrfs_next_leaf(root, path);
5290                         if (ret < 0)
5291                                 goto err;
5292                         else if (ret > 0)
5293                                 break;
5294                         continue;
5295                 }
5296
5297                 item = btrfs_item_nr(slot);
5298                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
5299
5300                 if (found_key.objectid != key.objectid)
5301                         break;
5302                 if (btrfs_key_type(&found_key) != key_type)
5303                         break;
5304                 if (found_key.offset < ctx->pos)
5305                         goto next;
5306                 if (key_type == BTRFS_DIR_INDEX_KEY &&
5307                     btrfs_should_delete_dir_index(&del_list,
5308                                                   found_key.offset))
5309                         goto next;
5310
5311                 ctx->pos = found_key.offset;
5312                 is_curr = 1;
5313
5314                 di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
5315                 di_cur = 0;
5316                 di_total = btrfs_item_size(leaf, item);
5317
5318                 while (di_cur < di_total) {
5319                         struct btrfs_key location;
5320
5321                         if (verify_dir_item(root, leaf, di))
5322                                 break;
5323
5324                         name_len = btrfs_dir_name_len(leaf, di);
5325                         if (name_len <= sizeof(tmp_name)) {
5326                                 name_ptr = tmp_name;
5327                         } else {
5328                                 name_ptr = kmalloc(name_len, GFP_NOFS);
5329                                 if (!name_ptr) {
5330                                         ret = -ENOMEM;
5331                                         goto err;
5332                                 }
5333                         }
5334                         read_extent_buffer(leaf, name_ptr,
5335                                            (unsigned long)(di + 1), name_len);
5336
5337                         d_type = btrfs_filetype_table[btrfs_dir_type(leaf, di)];
5338                         btrfs_dir_item_key_to_cpu(leaf, di, &location);
5339
5340
5341                         /* is this a reference to our own snapshot? If so
5342                          * skip it.
5343                          *
5344                          * In contrast to old kernels, we insert the snapshot's
5345                          * dir item and dir index after it has been created, so
5346                          * we won't find a reference to our own snapshot. We
5347                          * still keep the following code for backward
5348                          * compatibility.
5349                          */
5350                         if (location.type == BTRFS_ROOT_ITEM_KEY &&
5351                             location.objectid == root->root_key.objectid) {
5352                                 over = 0;
5353                                 goto skip;
5354                         }
5355                         over = !dir_emit(ctx, name_ptr, name_len,
5356                                        location.objectid, d_type);
5357
5358 skip:
5359                         if (name_ptr != tmp_name)
5360                                 kfree(name_ptr);
5361
5362                         if (over)
5363                                 goto nopos;
5364                         di_len = btrfs_dir_name_len(leaf, di) +
5365                                  btrfs_dir_data_len(leaf, di) + sizeof(*di);
5366                         di_cur += di_len;
5367                         di = (struct btrfs_dir_item *)((char *)di + di_len);
5368                 }
5369 next:
5370                 path->slots[0]++;
5371         }
5372
5373         if (key_type == BTRFS_DIR_INDEX_KEY) {
5374                 if (is_curr)
5375                         ctx->pos++;
5376                 ret = btrfs_readdir_delayed_dir_index(ctx, &ins_list);
5377                 if (ret)
5378                         goto nopos;
5379         }
5380
5381         /* Reached end of directory/root. Bump pos past the last item. */
5382         ctx->pos++;
5383
5384         /*
5385          * Stop new entries from being returned after we return the last
5386          * entry.
5387          *
5388          * New directory entries are assigned a strictly increasing
5389          * offset.  This means that new entries created during readdir
5390          * are *guaranteed* to be seen in the future by that readdir.
5391          * This has broken buggy programs which operate on names as
5392          * they're returned by readdir.  Until we re-use freed offsets
5393          * we have this hack to stop new entries from being returned
5394          * under the assumption that they'll never reach this huge
5395          * offset.
5396          *
5397          * This is being careful not to overflow 32bit loff_t unless the
5398          * last entry requires it because doing so has broken 32bit apps
5399          * in the past.
5400          */
5401         if (key_type == BTRFS_DIR_INDEX_KEY) {
5402                 if (ctx->pos >= INT_MAX)
5403                         ctx->pos = LLONG_MAX;
5404                 else
5405                         ctx->pos = INT_MAX;
5406         }
5407 nopos:
5408         ret = 0;
5409 err:
5410         if (key_type == BTRFS_DIR_INDEX_KEY)
5411                 btrfs_put_delayed_items(&ins_list, &del_list);
5412         btrfs_free_path(path);
5413         return ret;
5414 }
5415
5416 int btrfs_write_inode(struct inode *inode, struct writeback_control *wbc)
5417 {
5418         struct btrfs_root *root = BTRFS_I(inode)->root;
5419         struct btrfs_trans_handle *trans;
5420         int ret = 0;
5421         bool nolock = false;
5422
5423         if (test_bit(BTRFS_INODE_DUMMY, &BTRFS_I(inode)->runtime_flags))
5424                 return 0;
5425
5426         if (btrfs_fs_closing(root->fs_info) && btrfs_is_free_space_inode(inode))
5427                 nolock = true;
5428
5429         if (wbc->sync_mode == WB_SYNC_ALL) {
5430                 if (nolock)
5431                         trans = btrfs_join_transaction_nolock(root);
5432                 else
5433                         trans = btrfs_join_transaction(root);
5434                 if (IS_ERR(trans))
5435                         return PTR_ERR(trans);
5436                 ret = btrfs_commit_transaction(trans, root);
5437         }
5438         return ret;
5439 }
5440
5441 /*
5442  * This is somewhat expensive, updating the tree every time the
5443  * inode changes.  But, it is most likely to find the inode in cache.
5444  * FIXME, needs more benchmarking...there are no reasons other than performance
5445  * to keep or drop this code.
5446  */
5447 static int btrfs_dirty_inode(struct inode *inode)
5448 {
5449         struct btrfs_root *root = BTRFS_I(inode)->root;
5450         struct btrfs_trans_handle *trans;
5451         int ret;
5452
5453         if (test_bit(BTRFS_INODE_DUMMY, &BTRFS_I(inode)->runtime_flags))
5454                 return 0;
5455
5456         trans = btrfs_join_transaction(root);
5457         if (IS_ERR(trans))
5458                 return PTR_ERR(trans);
5459
5460         ret = btrfs_update_inode(trans, root, inode);
5461         if (ret && ret == -ENOSPC) {
5462                 /* whoops, lets try again with the full transaction */
5463                 btrfs_end_transaction(trans, root);
5464                 trans = btrfs_start_transaction(root, 1);
5465                 if (IS_ERR(trans))
5466                         return PTR_ERR(trans);
5467
5468                 ret = btrfs_update_inode(trans, root, inode);
5469         }
5470         btrfs_end_transaction(trans, root);
5471         if (BTRFS_I(inode)->delayed_node)
5472                 btrfs_balance_delayed_items(root);
5473
5474         return ret;
5475 }
5476
5477 /*
5478  * This is a copy of file_update_time.  We need this so we can return error on
5479  * ENOSPC for updating the inode in the case of file write and mmap writes.
5480  */
5481 static int btrfs_update_time(struct inode *inode, struct timespec *now,
5482                              int flags)
5483 {
5484         struct btrfs_root *root = BTRFS_I(inode)->root;
5485
5486         if (btrfs_root_readonly(root))
5487                 return -EROFS;
5488
5489         if (flags & S_VERSION)
5490                 inode_inc_iversion(inode);
5491         if (flags & S_CTIME)
5492                 inode->i_ctime = *now;
5493         if (flags & S_MTIME)
5494                 inode->i_mtime = *now;
5495         if (flags & S_ATIME)
5496                 inode->i_atime = *now;
5497         return btrfs_dirty_inode(inode);
5498 }
5499
5500 /*
5501  * find the highest existing sequence number in a directory
5502  * and then set the in-memory index_cnt variable to reflect
5503  * free sequence numbers
5504  */
5505 static int btrfs_set_inode_index_count(struct inode *inode)
5506 {
5507         struct btrfs_root *root = BTRFS_I(inode)->root;
5508         struct btrfs_key key, found_key;
5509         struct btrfs_path *path;
5510         struct extent_buffer *leaf;
5511         int ret;
5512
5513         key.objectid = btrfs_ino(inode);
5514         btrfs_set_key_type(&key, BTRFS_DIR_INDEX_KEY);
5515         key.offset = (u64)-1;
5516
5517         path = btrfs_alloc_path();
5518         if (!path)
5519                 return -ENOMEM;
5520
5521         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
5522         if (ret < 0)
5523                 goto out;
5524         /* FIXME: we should be able to handle this */
5525         if (ret == 0)
5526                 goto out;
5527         ret = 0;
5528
5529         /*
5530          * MAGIC NUMBER EXPLANATION:
5531          * since we search a directory based on f_pos we have to start at 2
5532          * since '.' and '..' have f_pos of 0 and 1 respectively, so everybody
5533          * else has to start at 2
5534          */
5535         if (path->slots[0] == 0) {
5536                 BTRFS_I(inode)->index_cnt = 2;
5537                 goto out;
5538         }
5539
5540         path->slots[0]--;
5541
5542         leaf = path->nodes[0];
5543         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
5544
5545         if (found_key.objectid != btrfs_ino(inode) ||
5546             btrfs_key_type(&found_key) != BTRFS_DIR_INDEX_KEY) {
5547                 BTRFS_I(inode)->index_cnt = 2;
5548                 goto out;
5549         }
5550
5551         BTRFS_I(inode)->index_cnt = found_key.offset + 1;
5552 out:
5553         btrfs_free_path(path);
5554         return ret;
5555 }
5556
5557 /*
5558  * helper to find a free sequence number in a given directory.  This current
5559  * code is very simple, later versions will do smarter things in the btree
5560  */
5561 int btrfs_set_inode_index(struct inode *dir, u64 *index)
5562 {
5563         int ret = 0;
5564
5565         if (BTRFS_I(dir)->index_cnt == (u64)-1) {
5566                 ret = btrfs_inode_delayed_dir_index_count(dir);
5567                 if (ret) {
5568                         ret = btrfs_set_inode_index_count(dir);
5569                         if (ret)
5570                                 return ret;
5571                 }
5572         }
5573
5574         *index = BTRFS_I(dir)->index_cnt;
5575         BTRFS_I(dir)->index_cnt++;
5576
5577         return ret;
5578 }
5579
5580 static struct inode *btrfs_new_inode(struct btrfs_trans_handle *trans,
5581                                      struct btrfs_root *root,
5582                                      struct inode *dir,
5583                                      const char *name, int name_len,
5584                                      u64 ref_objectid, u64 objectid,
5585                                      umode_t mode, u64 *index)
5586 {
5587         struct inode *inode;
5588         struct btrfs_inode_item *inode_item;
5589         struct btrfs_key *location;
5590         struct btrfs_path *path;
5591         struct btrfs_inode_ref *ref;
5592         struct btrfs_key key[2];
5593         u32 sizes[2];
5594         int nitems = name ? 2 : 1;
5595         unsigned long ptr;
5596         int ret;
5597
5598         path = btrfs_alloc_path();
5599         if (!path)
5600                 return ERR_PTR(-ENOMEM);
5601
5602         inode = new_inode(root->fs_info->sb);
5603         if (!inode) {
5604                 btrfs_free_path(path);
5605                 return ERR_PTR(-ENOMEM);
5606         }
5607
5608         /*
5609          * we have to initialize this early, so we can reclaim the inode
5610          * number if we fail afterwards in this function.
5611          */
5612         inode->i_ino = objectid;
5613
5614         if (dir && name) {
5615                 trace_btrfs_inode_request(dir);
5616
5617                 ret = btrfs_set_inode_index(dir, index);
5618                 if (ret) {
5619                         btrfs_free_path(path);
5620                         iput(inode);
5621                         return ERR_PTR(ret);
5622                 }
5623         } else if (dir) {
5624                 *index = 0;
5625         }
5626         /*
5627          * index_cnt is ignored for everything but a dir,
5628          * btrfs_get_inode_index_count has an explanation for the magic
5629          * number
5630          */
5631         BTRFS_I(inode)->index_cnt = 2;
5632         BTRFS_I(inode)->dir_index = *index;
5633         BTRFS_I(inode)->root = root;
5634         BTRFS_I(inode)->generation = trans->transid;
5635         inode->i_generation = BTRFS_I(inode)->generation;
5636
5637         /*
5638          * We could have gotten an inode number from somebody who was fsynced
5639          * and then removed in this same transaction, so let's just set full
5640          * sync since it will be a full sync anyway and this will blow away the
5641          * old info in the log.
5642          */
5643         set_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &BTRFS_I(inode)->runtime_flags);
5644
5645         key[0].objectid = objectid;
5646         btrfs_set_key_type(&key[0], BTRFS_INODE_ITEM_KEY);
5647         key[0].offset = 0;
5648
5649         sizes[0] = sizeof(struct btrfs_inode_item);
5650
5651         if (name) {
5652                 /*
5653                  * Start new inodes with an inode_ref. This is slightly more
5654                  * efficient for small numbers of hard links since they will
5655                  * be packed into one item. Extended refs will kick in if we
5656                  * add more hard links than can fit in the ref item.
5657                  */
5658                 key[1].objectid = objectid;
5659                 btrfs_set_key_type(&key[1], BTRFS_INODE_REF_KEY);
5660                 key[1].offset = ref_objectid;
5661
5662                 sizes[1] = name_len + sizeof(*ref);
5663         }
5664
5665         path->leave_spinning = 1;
5666         ret = btrfs_insert_empty_items(trans, root, path, key, sizes, nitems);
5667         if (ret != 0)
5668                 goto fail;
5669
5670         inode_init_owner(inode, dir, mode);
5671         inode_set_bytes(inode, 0);
5672         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
5673         inode_item = btrfs_item_ptr(path->nodes[0], path->slots[0],
5674                                   struct btrfs_inode_item);
5675         memset_extent_buffer(path->nodes[0], 0, (unsigned long)inode_item,
5676                              sizeof(*inode_item));
5677         fill_inode_item(trans, path->nodes[0], inode_item, inode);
5678
5679         if (name) {
5680                 ref = btrfs_item_ptr(path->nodes[0], path->slots[0] + 1,
5681                                      struct btrfs_inode_ref);
5682                 btrfs_set_inode_ref_name_len(path->nodes[0], ref, name_len);
5683                 btrfs_set_inode_ref_index(path->nodes[0], ref, *index);
5684                 ptr = (unsigned long)(ref + 1);
5685                 write_extent_buffer(path->nodes[0], name, ptr, name_len);
5686         }
5687
5688         btrfs_mark_buffer_dirty(path->nodes[0]);
5689         btrfs_free_path(path);
5690
5691         location = &BTRFS_I(inode)->location;
5692         location->objectid = objectid;
5693         location->offset = 0;
5694         btrfs_set_key_type(location, BTRFS_INODE_ITEM_KEY);
5695
5696         btrfs_inherit_iflags(inode, dir);
5697
5698         if (S_ISREG(mode)) {
5699                 if (btrfs_test_opt(root, NODATASUM))
5700                         BTRFS_I(inode)->flags |= BTRFS_INODE_NODATASUM;
5701                 if (btrfs_test_opt(root, NODATACOW))
5702                         BTRFS_I(inode)->flags |= BTRFS_INODE_NODATACOW |
5703                                 BTRFS_INODE_NODATASUM;
5704         }
5705
5706         btrfs_insert_inode_hash(inode);
5707         inode_tree_add(inode);
5708
5709         trace_btrfs_inode_new(inode);
5710         btrfs_set_inode_last_trans(trans, inode);
5711
5712         btrfs_update_root_times(trans, root);
5713
5714         ret = btrfs_inode_inherit_props(trans, inode, dir);
5715         if (ret)
5716                 btrfs_err(root->fs_info,
5717                           "error inheriting props for ino %llu (root %llu): %d",
5718                           btrfs_ino(inode), root->root_key.objectid, ret);
5719
5720         return inode;
5721 fail:
5722         if (dir && name)
5723                 BTRFS_I(dir)->index_cnt--;
5724         btrfs_free_path(path);
5725         iput(inode);
5726         return ERR_PTR(ret);
5727 }
5728
5729 static inline u8 btrfs_inode_type(struct inode *inode)
5730 {
5731         return btrfs_type_by_mode[(inode->i_mode & S_IFMT) >> S_SHIFT];
5732 }
5733
5734 /*
5735  * utility function to add 'inode' into 'parent_inode' with
5736  * a give name and a given sequence number.
5737  * if 'add_backref' is true, also insert a backref from the
5738  * inode to the parent directory.
5739  */
5740 int btrfs_add_link(struct btrfs_trans_handle *trans,
5741                    struct inode *parent_inode, struct inode *inode,
5742                    const char *name, int name_len, int add_backref, u64 index)
5743 {
5744         int ret = 0;
5745         struct btrfs_key key;
5746         struct btrfs_root *root = BTRFS_I(parent_inode)->root;
5747         u64 ino = btrfs_ino(inode);
5748         u64 parent_ino = btrfs_ino(parent_inode);
5749
5750         if (unlikely(ino == BTRFS_FIRST_FREE_OBJECTID)) {
5751                 memcpy(&key, &BTRFS_I(inode)->root->root_key, sizeof(key));
5752         } else {
5753                 key.objectid = ino;
5754                 btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY);
5755                 key.offset = 0;
5756         }
5757
5758         if (unlikely(ino == BTRFS_FIRST_FREE_OBJECTID)) {
5759                 ret = btrfs_add_root_ref(trans, root->fs_info->tree_root,
5760                                          key.objectid, root->root_key.objectid,
5761                                          parent_ino, index, name, name_len);
5762         } else if (add_backref) {
5763                 ret = btrfs_insert_inode_ref(trans, root, name, name_len, ino,
5764                                              parent_ino, index);
5765         }
5766
5767         /* Nothing to clean up yet */
5768         if (ret)
5769                 return ret;
5770
5771         ret = btrfs_insert_dir_item(trans, root, name, name_len,
5772                                     parent_inode, &key,
5773                                     btrfs_inode_type(inode), index);
5774         if (ret == -EEXIST || ret == -EOVERFLOW)
5775                 goto fail_dir_item;
5776         else if (ret) {
5777                 btrfs_abort_transaction(trans, root, ret);
5778                 return ret;
5779         }
5780
5781         btrfs_i_size_write(parent_inode, parent_inode->i_size +
5782                            name_len * 2);
5783         inode_inc_iversion(parent_inode);
5784         parent_inode->i_mtime = parent_inode->i_ctime = CURRENT_TIME;
5785         ret = btrfs_update_inode(trans, root, parent_inode);
5786         if (ret)
5787                 btrfs_abort_transaction(trans, root, ret);
5788         return ret;
5789
5790 fail_dir_item:
5791         if (unlikely(ino == BTRFS_FIRST_FREE_OBJECTID)) {
5792                 u64 local_index;
5793                 int err;
5794                 err = btrfs_del_root_ref(trans, root->fs_info->tree_root,
5795                                  key.objectid, root->root_key.objectid,
5796                                  parent_ino, &local_index, name, name_len);
5797
5798         } else if (add_backref) {
5799                 u64 local_index;
5800                 int err;
5801
5802                 err = btrfs_del_inode_ref(trans, root, name, name_len,
5803                                           ino, parent_ino, &local_index);
5804         }
5805         return ret;
5806 }
5807
5808 static int btrfs_add_nondir(struct btrfs_trans_handle *trans,
5809                             struct inode *dir, struct dentry *dentry,
5810                             struct inode *inode, int backref, u64 index)
5811 {
5812         int err = btrfs_add_link(trans, dir, inode,
5813                                  dentry->d_name.name, dentry->d_name.len,
5814                                  backref, index);
5815         if (err > 0)
5816                 err = -EEXIST;
5817         return err;
5818 }
5819
5820 static int btrfs_mknod(struct inode *dir, struct dentry *dentry,
5821                         umode_t mode, dev_t rdev)
5822 {
5823         struct btrfs_trans_handle *trans;
5824         struct btrfs_root *root = BTRFS_I(dir)->root;
5825         struct inode *inode = NULL;
5826         int err;
5827         int drop_inode = 0;
5828         u64 objectid;
5829         u64 index = 0;
5830
5831         if (!new_valid_dev(rdev))
5832                 return -EINVAL;
5833
5834         /*
5835          * 2 for inode item and ref
5836          * 2 for dir items
5837          * 1 for xattr if selinux is on
5838          */
5839         trans = btrfs_start_transaction(root, 5);
5840         if (IS_ERR(trans))
5841                 return PTR_ERR(trans);
5842
5843         err = btrfs_find_free_ino(root, &objectid);
5844         if (err)
5845                 goto out_unlock;
5846
5847         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
5848                                 dentry->d_name.len, btrfs_ino(dir), objectid,
5849                                 mode, &index);
5850         if (IS_ERR(inode)) {
5851                 err = PTR_ERR(inode);
5852                 goto out_unlock;
5853         }
5854
5855         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
5856         if (err) {
5857                 drop_inode = 1;
5858                 goto out_unlock;
5859         }
5860
5861         /*
5862         * If the active LSM wants to access the inode during
5863         * d_instantiate it needs these. Smack checks to see
5864         * if the filesystem supports xattrs by looking at the
5865         * ops vector.
5866         */
5867
5868         inode->i_op = &btrfs_special_inode_operations;
5869         err = btrfs_add_nondir(trans, dir, dentry, inode, 0, index);
5870         if (err)
5871                 drop_inode = 1;
5872         else {
5873                 init_special_inode(inode, inode->i_mode, rdev);
5874                 btrfs_update_inode(trans, root, inode);
5875                 d_instantiate(dentry, inode);
5876         }
5877 out_unlock:
5878         btrfs_end_transaction(trans, root);
5879         btrfs_balance_delayed_items(root);
5880         btrfs_btree_balance_dirty(root);
5881         if (drop_inode) {
5882                 inode_dec_link_count(inode);
5883                 iput(inode);
5884         }
5885         return err;
5886 }
5887
5888 static int btrfs_create(struct inode *dir, struct dentry *dentry,
5889                         umode_t mode, bool excl)
5890 {
5891         struct btrfs_trans_handle *trans;
5892         struct btrfs_root *root = BTRFS_I(dir)->root;
5893         struct inode *inode = NULL;
5894         int drop_inode_on_err = 0;
5895         int err;
5896         u64 objectid;
5897         u64 index = 0;
5898
5899         /*
5900          * 2 for inode item and ref
5901          * 2 for dir items
5902          * 1 for xattr if selinux is on
5903          */
5904         trans = btrfs_start_transaction(root, 5);
5905         if (IS_ERR(trans))
5906                 return PTR_ERR(trans);
5907
5908         err = btrfs_find_free_ino(root, &objectid);
5909         if (err)
5910                 goto out_unlock;
5911
5912         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
5913                                 dentry->d_name.len, btrfs_ino(dir), objectid,
5914                                 mode, &index);
5915         if (IS_ERR(inode)) {
5916                 err = PTR_ERR(inode);
5917                 goto out_unlock;
5918         }
5919         drop_inode_on_err = 1;
5920
5921         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
5922         if (err)
5923                 goto out_unlock;
5924
5925         err = btrfs_update_inode(trans, root, inode);
5926         if (err)
5927                 goto out_unlock;
5928
5929         /*
5930         * If the active LSM wants to access the inode during
5931         * d_instantiate it needs these. Smack checks to see
5932         * if the filesystem supports xattrs by looking at the
5933         * ops vector.
5934         */
5935         inode->i_fop = &btrfs_file_operations;
5936         inode->i_op = &btrfs_file_inode_operations;
5937
5938         err = btrfs_add_nondir(trans, dir, dentry, inode, 0, index);
5939         if (err)
5940                 goto out_unlock;
5941
5942         inode->i_mapping->a_ops = &btrfs_aops;
5943         inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
5944         BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
5945         d_instantiate(dentry, inode);
5946
5947 out_unlock:
5948         btrfs_end_transaction(trans, root);
5949         if (err && drop_inode_on_err) {
5950                 inode_dec_link_count(inode);
5951                 iput(inode);
5952         }
5953         btrfs_balance_delayed_items(root);
5954         btrfs_btree_balance_dirty(root);
5955         return err;
5956 }
5957
5958 static int btrfs_link(struct dentry *old_dentry, struct inode *dir,
5959                       struct dentry *dentry)
5960 {
5961         struct btrfs_trans_handle *trans;
5962         struct btrfs_root *root = BTRFS_I(dir)->root;
5963         struct inode *inode = old_dentry->d_inode;
5964         u64 index;
5965         int err;
5966         int drop_inode = 0;
5967
5968         /* do not allow sys_link's with other subvols of the same device */
5969         if (root->objectid != BTRFS_I(inode)->root->objectid)
5970                 return -EXDEV;
5971
5972         if (inode->i_nlink >= BTRFS_LINK_MAX)
5973                 return -EMLINK;
5974
5975         err = btrfs_set_inode_index(dir, &index);
5976         if (err)
5977                 goto fail;
5978
5979         /*
5980          * 2 items for inode and inode ref
5981          * 2 items for dir items
5982          * 1 item for parent inode
5983          */
5984         trans = btrfs_start_transaction(root, 5);
5985         if (IS_ERR(trans)) {
5986                 err = PTR_ERR(trans);
5987                 goto fail;
5988         }
5989
5990         /* There are several dir indexes for this inode, clear the cache. */
5991         BTRFS_I(inode)->dir_index = 0ULL;
5992         inc_nlink(inode);
5993         inode_inc_iversion(inode);
5994         inode->i_ctime = CURRENT_TIME;
5995         ihold(inode);
5996         set_bit(BTRFS_INODE_COPY_EVERYTHING, &BTRFS_I(inode)->runtime_flags);
5997
5998         err = btrfs_add_nondir(trans, dir, dentry, inode, 1, index);
5999
6000         if (err) {
6001                 drop_inode = 1;
6002         } else {
6003                 struct dentry *parent = dentry->d_parent;
6004                 err = btrfs_update_inode(trans, root, inode);
6005                 if (err)
6006                         goto fail;
6007                 if (inode->i_nlink == 1) {
6008                         /*
6009                          * If new hard link count is 1, it's a file created
6010                          * with open(2) O_TMPFILE flag.
6011                          */
6012                         err = btrfs_orphan_del(trans, inode);
6013                         if (err)
6014                                 goto fail;
6015                 }
6016                 d_instantiate(dentry, inode);
6017                 btrfs_log_new_name(trans, inode, NULL, parent);
6018         }
6019
6020         btrfs_end_transaction(trans, root);
6021         btrfs_balance_delayed_items(root);
6022 fail:
6023         if (drop_inode) {
6024                 inode_dec_link_count(inode);
6025                 iput(inode);
6026         }
6027         btrfs_btree_balance_dirty(root);
6028         return err;
6029 }
6030
6031 static int btrfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
6032 {
6033         struct inode *inode = NULL;
6034         struct btrfs_trans_handle *trans;
6035         struct btrfs_root *root = BTRFS_I(dir)->root;
6036         int err = 0;
6037         int drop_on_err = 0;
6038         u64 objectid = 0;
6039         u64 index = 0;
6040
6041         /*
6042          * 2 items for inode and ref
6043          * 2 items for dir items
6044          * 1 for xattr if selinux is on
6045          */
6046         trans = btrfs_start_transaction(root, 5);
6047         if (IS_ERR(trans))
6048                 return PTR_ERR(trans);
6049
6050         err = btrfs_find_free_ino(root, &objectid);
6051         if (err)
6052                 goto out_fail;
6053
6054         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
6055                                 dentry->d_name.len, btrfs_ino(dir), objectid,
6056                                 S_IFDIR | mode, &index);
6057         if (IS_ERR(inode)) {
6058                 err = PTR_ERR(inode);
6059                 goto out_fail;
6060         }
6061
6062         drop_on_err = 1;
6063
6064         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
6065         if (err)
6066                 goto out_fail;
6067
6068         inode->i_op = &btrfs_dir_inode_operations;
6069         inode->i_fop = &btrfs_dir_file_operations;
6070
6071         btrfs_i_size_write(inode, 0);
6072         err = btrfs_update_inode(trans, root, inode);
6073         if (err)
6074                 goto out_fail;
6075
6076         err = btrfs_add_link(trans, dir, inode, dentry->d_name.name,
6077                              dentry->d_name.len, 0, index);
6078         if (err)
6079                 goto out_fail;
6080
6081         d_instantiate(dentry, inode);
6082         drop_on_err = 0;
6083
6084 out_fail:
6085         btrfs_end_transaction(trans, root);
6086         if (drop_on_err)
6087                 iput(inode);
6088         btrfs_balance_delayed_items(root);
6089         btrfs_btree_balance_dirty(root);
6090         return err;
6091 }
6092
6093 /* helper for btfs_get_extent.  Given an existing extent in the tree,
6094  * and an extent that you want to insert, deal with overlap and insert
6095  * the new extent into the tree.
6096  */
6097 static int merge_extent_mapping(struct extent_map_tree *em_tree,
6098                                 struct extent_map *existing,
6099                                 struct extent_map *em,
6100                                 u64 map_start, u64 map_len)
6101 {
6102         u64 start_diff;
6103
6104         BUG_ON(map_start < em->start || map_start >= extent_map_end(em));
6105         start_diff = map_start - em->start;
6106         em->start = map_start;
6107         em->len = map_len;
6108         if (em->block_start < EXTENT_MAP_LAST_BYTE &&
6109             !test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
6110                 em->block_start += start_diff;
6111                 em->block_len -= start_diff;
6112         }
6113         return add_extent_mapping(em_tree, em, 0);
6114 }
6115
6116 static noinline int uncompress_inline(struct btrfs_path *path,
6117                                       struct inode *inode, struct page *page,
6118                                       size_t pg_offset, u64 extent_offset,
6119                                       struct btrfs_file_extent_item *item)
6120 {
6121         int ret;
6122         struct extent_buffer *leaf = path->nodes[0];
6123         char *tmp;
6124         size_t max_size;
6125         unsigned long inline_size;
6126         unsigned long ptr;
6127         int compress_type;
6128
6129         WARN_ON(pg_offset != 0);
6130         compress_type = btrfs_file_extent_compression(leaf, item);
6131         max_size = btrfs_file_extent_ram_bytes(leaf, item);
6132         inline_size = btrfs_file_extent_inline_item_len(leaf,
6133                                         btrfs_item_nr(path->slots[0]));
6134         tmp = kmalloc(inline_size, GFP_NOFS);
6135         if (!tmp)
6136                 return -ENOMEM;
6137         ptr = btrfs_file_extent_inline_start(item);
6138
6139         read_extent_buffer(leaf, tmp, ptr, inline_size);
6140
6141         max_size = min_t(unsigned long, PAGE_CACHE_SIZE, max_size);
6142         ret = btrfs_decompress(compress_type, tmp, page,
6143                                extent_offset, inline_size, max_size);
6144         kfree(tmp);
6145         return ret;
6146 }
6147
6148 /*
6149  * a bit scary, this does extent mapping from logical file offset to the disk.
6150  * the ugly parts come from merging extents from the disk with the in-ram
6151  * representation.  This gets more complex because of the data=ordered code,
6152  * where the in-ram extents might be locked pending data=ordered completion.
6153  *
6154  * This also copies inline extents directly into the page.
6155  */
6156
6157 struct extent_map *btrfs_get_extent(struct inode *inode, struct page *page,
6158                                     size_t pg_offset, u64 start, u64 len,
6159                                     int create)
6160 {
6161         int ret;
6162         int err = 0;
6163         u64 extent_start = 0;
6164         u64 extent_end = 0;
6165         u64 objectid = btrfs_ino(inode);
6166         u32 found_type;
6167         struct btrfs_path *path = NULL;
6168         struct btrfs_root *root = BTRFS_I(inode)->root;
6169         struct btrfs_file_extent_item *item;
6170         struct extent_buffer *leaf;
6171         struct btrfs_key found_key;
6172         struct extent_map *em = NULL;
6173         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
6174         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
6175         struct btrfs_trans_handle *trans = NULL;
6176         const bool new_inline = !page || create;
6177
6178 again:
6179         read_lock(&em_tree->lock);
6180         em = lookup_extent_mapping(em_tree, start, len);
6181         if (em)
6182                 em->bdev = root->fs_info->fs_devices->latest_bdev;
6183         read_unlock(&em_tree->lock);
6184
6185         if (em) {
6186                 if (em->start > start || em->start + em->len <= start)
6187                         free_extent_map(em);
6188                 else if (em->block_start == EXTENT_MAP_INLINE && page)
6189                         free_extent_map(em);
6190                 else
6191                         goto out;
6192         }
6193         em = alloc_extent_map();
6194         if (!em) {
6195                 err = -ENOMEM;
6196                 goto out;
6197         }
6198         em->bdev = root->fs_info->fs_devices->latest_bdev;
6199         em->start = EXTENT_MAP_HOLE;
6200         em->orig_start = EXTENT_MAP_HOLE;
6201         em->len = (u64)-1;
6202         em->block_len = (u64)-1;
6203
6204         if (!path) {
6205                 path = btrfs_alloc_path();
6206                 if (!path) {
6207                         err = -ENOMEM;
6208                         goto out;
6209                 }
6210                 /*
6211                  * Chances are we'll be called again, so go ahead and do
6212                  * readahead
6213                  */
6214                 path->reada = 1;
6215         }
6216
6217         ret = btrfs_lookup_file_extent(trans, root, path,
6218                                        objectid, start, trans != NULL);
6219         if (ret < 0) {
6220                 err = ret;
6221                 goto out;
6222         }
6223
6224         if (ret != 0) {
6225                 if (path->slots[0] == 0)
6226                         goto not_found;
6227                 path->slots[0]--;
6228         }
6229
6230         leaf = path->nodes[0];
6231         item = btrfs_item_ptr(leaf, path->slots[0],
6232                               struct btrfs_file_extent_item);
6233         /* are we inside the extent that was found? */
6234         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
6235         found_type = btrfs_key_type(&found_key);
6236         if (found_key.objectid != objectid ||
6237             found_type != BTRFS_EXTENT_DATA_KEY) {
6238                 /*
6239                  * If we backup past the first extent we want to move forward
6240                  * and see if there is an extent in front of us, otherwise we'll
6241                  * say there is a hole for our whole search range which can
6242                  * cause problems.
6243                  */
6244                 extent_end = start;
6245                 goto next;
6246         }
6247
6248         found_type = btrfs_file_extent_type(leaf, item);
6249         extent_start = found_key.offset;
6250         if (found_type == BTRFS_FILE_EXTENT_REG ||
6251             found_type == BTRFS_FILE_EXTENT_PREALLOC) {
6252                 extent_end = extent_start +
6253                        btrfs_file_extent_num_bytes(leaf, item);
6254         } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
6255                 size_t size;
6256                 size = btrfs_file_extent_inline_len(leaf, path->slots[0], item);
6257                 extent_end = ALIGN(extent_start + size, root->sectorsize);
6258         }
6259 next:
6260         if (start >= extent_end) {
6261                 path->slots[0]++;
6262                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
6263                         ret = btrfs_next_leaf(root, path);
6264                         if (ret < 0) {
6265                                 err = ret;
6266                                 goto out;
6267                         }
6268                         if (ret > 0)
6269                                 goto not_found;
6270                         leaf = path->nodes[0];
6271                 }
6272                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
6273                 if (found_key.objectid != objectid ||
6274                     found_key.type != BTRFS_EXTENT_DATA_KEY)
6275                         goto not_found;
6276                 if (start + len <= found_key.offset)
6277                         goto not_found;
6278                 em->start = start;
6279                 em->orig_start = start;
6280                 em->len = found_key.offset - start;
6281                 goto not_found_em;
6282         }
6283
6284         btrfs_extent_item_to_extent_map(inode, path, item, new_inline, em);
6285
6286         if (found_type == BTRFS_FILE_EXTENT_REG ||
6287             found_type == BTRFS_FILE_EXTENT_PREALLOC) {
6288                 goto insert;
6289         } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
6290                 unsigned long ptr;
6291                 char *map;
6292                 size_t size;
6293                 size_t extent_offset;
6294                 size_t copy_size;
6295
6296                 if (new_inline)
6297                         goto out;
6298
6299                 size = btrfs_file_extent_inline_len(leaf, path->slots[0], item);
6300                 extent_offset = page_offset(page) + pg_offset - extent_start;
6301                 copy_size = min_t(u64, PAGE_CACHE_SIZE - pg_offset,
6302                                 size - extent_offset);
6303                 em->start = extent_start + extent_offset;
6304                 em->len = ALIGN(copy_size, root->sectorsize);
6305                 em->orig_block_len = em->len;
6306                 em->orig_start = em->start;
6307                 ptr = btrfs_file_extent_inline_start(item) + extent_offset;
6308                 if (create == 0 && !PageUptodate(page)) {
6309                         if (btrfs_file_extent_compression(leaf, item) !=
6310                             BTRFS_COMPRESS_NONE) {
6311                                 ret = uncompress_inline(path, inode, page,
6312                                                         pg_offset,
6313                                                         extent_offset, item);
6314                                 if (ret) {
6315                                         err = ret;
6316                                         goto out;
6317                                 }
6318                         } else {
6319                                 map = kmap(page);
6320                                 read_extent_buffer(leaf, map + pg_offset, ptr,
6321                                                    copy_size);
6322                                 if (pg_offset + copy_size < PAGE_CACHE_SIZE) {
6323                                         memset(map + pg_offset + copy_size, 0,
6324                                                PAGE_CACHE_SIZE - pg_offset -
6325                                                copy_size);
6326                                 }
6327                                 kunmap(page);
6328                         }
6329                         flush_dcache_page(page);
6330                 } else if (create && PageUptodate(page)) {
6331                         BUG();
6332                         if (!trans) {
6333                                 kunmap(page);
6334                                 free_extent_map(em);
6335                                 em = NULL;
6336
6337                                 btrfs_release_path(path);
6338                                 trans = btrfs_join_transaction(root);
6339
6340                                 if (IS_ERR(trans))
6341                                         return ERR_CAST(trans);
6342                                 goto again;
6343                         }
6344                         map = kmap(page);
6345                         write_extent_buffer(leaf, map + pg_offset, ptr,
6346                                             copy_size);
6347                         kunmap(page);
6348                         btrfs_mark_buffer_dirty(leaf);
6349                 }
6350                 set_extent_uptodate(io_tree, em->start,
6351                                     extent_map_end(em) - 1, NULL, GFP_NOFS);
6352                 goto insert;
6353         }
6354 not_found:
6355         em->start = start;
6356         em->orig_start = start;
6357         em->len = len;
6358 not_found_em:
6359         em->block_start = EXTENT_MAP_HOLE;
6360         set_bit(EXTENT_FLAG_VACANCY, &em->flags);
6361 insert:
6362         btrfs_release_path(path);
6363         if (em->start > start || extent_map_end(em) <= start) {
6364                 btrfs_err(root->fs_info, "bad extent! em: [%llu %llu] passed [%llu %llu]",
6365                         em->start, em->len, start, len);
6366                 err = -EIO;
6367                 goto out;
6368         }
6369
6370         err = 0;
6371         write_lock(&em_tree->lock);
6372         ret = add_extent_mapping(em_tree, em, 0);
6373         /* it is possible that someone inserted the extent into the tree
6374          * while we had the lock dropped.  It is also possible that
6375          * an overlapping map exists in the tree
6376          */
6377         if (ret == -EEXIST) {
6378                 struct extent_map *existing;
6379
6380                 ret = 0;
6381
6382                 existing = lookup_extent_mapping(em_tree, start, len);
6383                 if (existing && (existing->start > start ||
6384                     existing->start + existing->len <= start)) {
6385                         free_extent_map(existing);
6386                         existing = NULL;
6387                 }
6388                 if (!existing) {
6389                         existing = lookup_extent_mapping(em_tree, em->start,
6390                                                          em->len);
6391                         if (existing) {
6392                                 err = merge_extent_mapping(em_tree, existing,
6393                                                            em, start,
6394                                                            root->sectorsize);
6395                                 free_extent_map(existing);
6396                                 if (err) {
6397                                         free_extent_map(em);
6398                                         em = NULL;
6399                                 }
6400                         } else {
6401                                 err = -EIO;
6402                                 free_extent_map(em);
6403                                 em = NULL;
6404                         }
6405                 } else {
6406                         free_extent_map(em);
6407                         em = existing;
6408                         err = 0;
6409                 }
6410         }
6411         write_unlock(&em_tree->lock);
6412 out:
6413
6414         trace_btrfs_get_extent(root, em);
6415
6416         if (path)
6417                 btrfs_free_path(path);
6418         if (trans) {
6419                 ret = btrfs_end_transaction(trans, root);
6420                 if (!err)
6421                         err = ret;
6422         }
6423         if (err) {
6424                 free_extent_map(em);
6425                 return ERR_PTR(err);
6426         }
6427         BUG_ON(!em); /* Error is always set */
6428         return em;
6429 }
6430
6431 struct extent_map *btrfs_get_extent_fiemap(struct inode *inode, struct page *page,
6432                                            size_t pg_offset, u64 start, u64 len,
6433                                            int create)
6434 {
6435         struct extent_map *em;
6436         struct extent_map *hole_em = NULL;
6437         u64 range_start = start;
6438         u64 end;
6439         u64 found;
6440         u64 found_end;
6441         int err = 0;
6442
6443         em = btrfs_get_extent(inode, page, pg_offset, start, len, create);
6444         if (IS_ERR(em))
6445                 return em;
6446         if (em) {
6447                 /*
6448                  * if our em maps to
6449                  * -  a hole or
6450                  * -  a pre-alloc extent,
6451                  * there might actually be delalloc bytes behind it.
6452                  */
6453                 if (em->block_start != EXTENT_MAP_HOLE &&
6454                     !test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
6455                         return em;
6456                 else
6457                         hole_em = em;
6458         }
6459
6460         /* check to see if we've wrapped (len == -1 or similar) */
6461         end = start + len;
6462         if (end < start)
6463                 end = (u64)-1;
6464         else
6465                 end -= 1;
6466
6467         em = NULL;
6468
6469         /* ok, we didn't find anything, lets look for delalloc */
6470         found = count_range_bits(&BTRFS_I(inode)->io_tree, &range_start,
6471                                  end, len, EXTENT_DELALLOC, 1);
6472         found_end = range_start + found;
6473         if (found_end < range_start)
6474                 found_end = (u64)-1;
6475
6476         /*
6477          * we didn't find anything useful, return
6478          * the original results from get_extent()
6479          */
6480         if (range_start > end || found_end <= start) {
6481                 em = hole_em;
6482                 hole_em = NULL;
6483                 goto out;
6484         }
6485
6486         /* adjust the range_start to make sure it doesn't
6487          * go backwards from the start they passed in
6488          */
6489         range_start = max(start, range_start);
6490         found = found_end - range_start;
6491
6492         if (found > 0) {
6493                 u64 hole_start = start;
6494                 u64 hole_len = len;
6495
6496                 em = alloc_extent_map();
6497                 if (!em) {
6498                         err = -ENOMEM;
6499                         goto out;
6500                 }
6501                 /*
6502                  * when btrfs_get_extent can't find anything it
6503                  * returns one huge hole
6504                  *
6505                  * make sure what it found really fits our range, and
6506                  * adjust to make sure it is based on the start from
6507                  * the caller
6508                  */
6509                 if (hole_em) {
6510                         u64 calc_end = extent_map_end(hole_em);
6511
6512                         if (calc_end <= start || (hole_em->start > end)) {
6513                                 free_extent_map(hole_em);
6514                                 hole_em = NULL;
6515                         } else {
6516                                 hole_start = max(hole_em->start, start);
6517                                 hole_len = calc_end - hole_start;
6518                         }
6519                 }
6520                 em->bdev = NULL;
6521                 if (hole_em && range_start > hole_start) {
6522                         /* our hole starts before our delalloc, so we
6523                          * have to return just the parts of the hole
6524                          * that go until  the delalloc starts
6525                          */
6526                         em->len = min(hole_len,
6527                                       range_start - hole_start);
6528                         em->start = hole_start;
6529                         em->orig_start = hole_start;
6530                         /*
6531                          * don't adjust block start at all,
6532                          * it is fixed at EXTENT_MAP_HOLE
6533                          */
6534                         em->block_start = hole_em->block_start;
6535                         em->block_len = hole_len;
6536                         if (test_bit(EXTENT_FLAG_PREALLOC, &hole_em->flags))
6537                                 set_bit(EXTENT_FLAG_PREALLOC, &em->flags);
6538                 } else {
6539                         em->start = range_start;
6540                         em->len = found;
6541                         em->orig_start = range_start;
6542                         em->block_start = EXTENT_MAP_DELALLOC;
6543                         em->block_len = found;
6544                 }
6545         } else if (hole_em) {
6546                 return hole_em;
6547         }
6548 out:
6549
6550         free_extent_map(hole_em);
6551         if (err) {
6552                 free_extent_map(em);
6553                 return ERR_PTR(err);
6554         }
6555         return em;
6556 }
6557
6558 static struct extent_map *btrfs_new_extent_direct(struct inode *inode,
6559                                                   u64 start, u64 len)
6560 {
6561         struct btrfs_root *root = BTRFS_I(inode)->root;
6562         struct extent_map *em;
6563         struct btrfs_key ins;
6564         u64 alloc_hint;
6565         int ret;
6566
6567         alloc_hint = get_extent_allocation_hint(inode, start, len);
6568         ret = btrfs_reserve_extent(root, len, root->sectorsize, 0,
6569                                    alloc_hint, &ins, 1, 1);
6570         if (ret)
6571                 return ERR_PTR(ret);
6572
6573         em = create_pinned_em(inode, start, ins.offset, start, ins.objectid,
6574                               ins.offset, ins.offset, ins.offset, 0);
6575         if (IS_ERR(em)) {
6576                 btrfs_free_reserved_extent(root, ins.objectid, ins.offset, 1);
6577                 return em;
6578         }
6579
6580         ret = btrfs_add_ordered_extent_dio(inode, start, ins.objectid,
6581                                            ins.offset, ins.offset, 0);
6582         if (ret) {
6583                 btrfs_free_reserved_extent(root, ins.objectid, ins.offset, 1);
6584                 free_extent_map(em);
6585                 return ERR_PTR(ret);
6586         }
6587
6588         return em;
6589 }
6590
6591 /*
6592  * returns 1 when the nocow is safe, < 1 on error, 0 if the
6593  * block must be cow'd
6594  */
6595 noinline int can_nocow_extent(struct inode *inode, u64 offset, u64 *len,
6596                               u64 *orig_start, u64 *orig_block_len,
6597                               u64 *ram_bytes)
6598 {
6599         struct btrfs_trans_handle *trans;
6600         struct btrfs_path *path;
6601         int ret;
6602         struct extent_buffer *leaf;
6603         struct btrfs_root *root = BTRFS_I(inode)->root;
6604         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
6605         struct btrfs_file_extent_item *fi;
6606         struct btrfs_key key;
6607         u64 disk_bytenr;
6608         u64 backref_offset;
6609         u64 extent_end;
6610         u64 num_bytes;
6611         int slot;
6612         int found_type;
6613         bool nocow = (BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW);
6614
6615         path = btrfs_alloc_path();
6616         if (!path)
6617                 return -ENOMEM;
6618
6619         ret = btrfs_lookup_file_extent(NULL, root, path, btrfs_ino(inode),
6620                                        offset, 0);
6621         if (ret < 0)
6622                 goto out;
6623
6624         slot = path->slots[0];
6625         if (ret == 1) {
6626                 if (slot == 0) {
6627                         /* can't find the item, must cow */
6628                         ret = 0;
6629                         goto out;
6630                 }
6631                 slot--;
6632         }
6633         ret = 0;
6634         leaf = path->nodes[0];
6635         btrfs_item_key_to_cpu(leaf, &key, slot);
6636         if (key.objectid != btrfs_ino(inode) ||
6637             key.type != BTRFS_EXTENT_DATA_KEY) {
6638                 /* not our file or wrong item type, must cow */
6639                 goto out;
6640         }
6641
6642         if (key.offset > offset) {
6643                 /* Wrong offset, must cow */
6644                 goto out;
6645         }
6646
6647         fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
6648         found_type = btrfs_file_extent_type(leaf, fi);
6649         if (found_type != BTRFS_FILE_EXTENT_REG &&
6650             found_type != BTRFS_FILE_EXTENT_PREALLOC) {
6651                 /* not a regular extent, must cow */
6652                 goto out;
6653         }
6654
6655         if (!nocow && found_type == BTRFS_FILE_EXTENT_REG)
6656                 goto out;
6657
6658         extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
6659         if (extent_end <= offset)
6660                 goto out;
6661
6662         disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
6663         if (disk_bytenr == 0)
6664                 goto out;
6665
6666         if (btrfs_file_extent_compression(leaf, fi) ||
6667             btrfs_file_extent_encryption(leaf, fi) ||
6668             btrfs_file_extent_other_encoding(leaf, fi))
6669                 goto out;
6670
6671         backref_offset = btrfs_file_extent_offset(leaf, fi);
6672
6673         if (orig_start) {
6674                 *orig_start = key.offset - backref_offset;
6675                 *orig_block_len = btrfs_file_extent_disk_num_bytes(leaf, fi);
6676                 *ram_bytes = btrfs_file_extent_ram_bytes(leaf, fi);
6677         }
6678
6679         if (btrfs_extent_readonly(root, disk_bytenr))
6680                 goto out;
6681
6682         num_bytes = min(offset + *len, extent_end) - offset;
6683         if (!nocow && found_type == BTRFS_FILE_EXTENT_PREALLOC) {
6684                 u64 range_end;
6685
6686                 range_end = round_up(offset + num_bytes, root->sectorsize) - 1;
6687                 ret = test_range_bit(io_tree, offset, range_end,
6688                                      EXTENT_DELALLOC, 0, NULL);
6689                 if (ret) {
6690                         ret = -EAGAIN;
6691                         goto out;
6692                 }
6693         }
6694
6695         btrfs_release_path(path);
6696
6697         /*
6698          * look for other files referencing this extent, if we
6699          * find any we must cow
6700          */
6701         trans = btrfs_join_transaction(root);
6702         if (IS_ERR(trans)) {
6703                 ret = 0;
6704                 goto out;
6705         }
6706
6707         ret = btrfs_cross_ref_exist(trans, root, btrfs_ino(inode),
6708                                     key.offset - backref_offset, disk_bytenr);
6709         btrfs_end_transaction(trans, root);
6710         if (ret) {
6711                 ret = 0;
6712                 goto out;
6713         }
6714
6715         /*
6716          * adjust disk_bytenr and num_bytes to cover just the bytes
6717          * in this extent we are about to write.  If there
6718          * are any csums in that range we have to cow in order
6719          * to keep the csums correct
6720          */
6721         disk_bytenr += backref_offset;
6722         disk_bytenr += offset - key.offset;
6723         if (csum_exist_in_range(root, disk_bytenr, num_bytes))
6724                                 goto out;
6725         /*
6726          * all of the above have passed, it is safe to overwrite this extent
6727          * without cow
6728          */
6729         *len = num_bytes;
6730         ret = 1;
6731 out:
6732         btrfs_free_path(path);
6733         return ret;
6734 }
6735
6736 bool btrfs_page_exists_in_range(struct inode *inode, loff_t start, loff_t end)
6737 {
6738         struct radix_tree_root *root = &inode->i_mapping->page_tree;
6739         int found = false;
6740         void **pagep = NULL;
6741         struct page *page = NULL;
6742         int start_idx;
6743         int end_idx;
6744
6745         start_idx = start >> PAGE_CACHE_SHIFT;
6746
6747         /*
6748          * end is the last byte in the last page.  end == start is legal
6749          */
6750         end_idx = end >> PAGE_CACHE_SHIFT;
6751
6752         rcu_read_lock();
6753
6754         /* Most of the code in this while loop is lifted from
6755          * find_get_page.  It's been modified to begin searching from a
6756          * page and return just the first page found in that range.  If the
6757          * found idx is less than or equal to the end idx then we know that
6758          * a page exists.  If no pages are found or if those pages are
6759          * outside of the range then we're fine (yay!) */
6760         while (page == NULL &&
6761                radix_tree_gang_lookup_slot(root, &pagep, NULL, start_idx, 1)) {
6762                 page = radix_tree_deref_slot(pagep);
6763                 if (unlikely(!page))
6764                         break;
6765
6766                 if (radix_tree_exception(page)) {
6767                         if (radix_tree_deref_retry(page)) {
6768                                 page = NULL;
6769                                 continue;
6770                         }
6771                         /*
6772                          * Otherwise, shmem/tmpfs must be storing a swap entry
6773                          * here as an exceptional entry: so return it without
6774                          * attempting to raise page count.
6775                          */
6776                         page = NULL;
6777                         break; /* TODO: Is this relevant for this use case? */
6778                 }
6779
6780                 if (!page_cache_get_speculative(page)) {
6781                         page = NULL;
6782                         continue;
6783                 }
6784
6785                 /*
6786                  * Has the page moved?
6787                  * This is part of the lockless pagecache protocol. See
6788                  * include/linux/pagemap.h for details.
6789                  */
6790                 if (unlikely(page != *pagep)) {
6791                         page_cache_release(page);
6792                         page = NULL;
6793                 }
6794         }
6795
6796         if (page) {
6797                 if (page->index <= end_idx)
6798                         found = true;
6799                 page_cache_release(page);
6800         }
6801
6802         rcu_read_unlock();
6803         return found;
6804 }
6805
6806 static int lock_extent_direct(struct inode *inode, u64 lockstart, u64 lockend,
6807                               struct extent_state **cached_state, int writing)
6808 {
6809         struct btrfs_ordered_extent *ordered;
6810         int ret = 0;
6811
6812         while (1) {
6813                 lock_extent_bits(&BTRFS_I(inode)->io_tree, lockstart, lockend,
6814                                  0, cached_state);
6815                 /*
6816                  * We're concerned with the entire range that we're going to be
6817                  * doing DIO to, so we need to make sure theres no ordered
6818                  * extents in this range.
6819                  */
6820                 ordered = btrfs_lookup_ordered_range(inode, lockstart,
6821                                                      lockend - lockstart + 1);
6822
6823                 /*
6824                  * We need to make sure there are no buffered pages in this
6825                  * range either, we could have raced between the invalidate in
6826                  * generic_file_direct_write and locking the extent.  The
6827                  * invalidate needs to happen so that reads after a write do not
6828                  * get stale data.
6829                  */
6830                 if (!ordered &&
6831                     (!writing ||
6832                      !btrfs_page_exists_in_range(inode, lockstart, lockend)))
6833                         break;
6834
6835                 unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart, lockend,
6836                                      cached_state, GFP_NOFS);
6837
6838                 if (ordered) {
6839                         btrfs_start_ordered_extent(inode, ordered, 1);
6840                         btrfs_put_ordered_extent(ordered);
6841                 } else {
6842                         /* Screw you mmap */
6843                         ret = filemap_write_and_wait_range(inode->i_mapping,
6844                                                            lockstart,
6845                                                            lockend);
6846                         if (ret)
6847                                 break;
6848
6849                         /*
6850                          * If we found a page that couldn't be invalidated just
6851                          * fall back to buffered.
6852                          */
6853                         ret = invalidate_inode_pages2_range(inode->i_mapping,
6854                                         lockstart >> PAGE_CACHE_SHIFT,
6855                                         lockend >> PAGE_CACHE_SHIFT);
6856                         if (ret)
6857                                 break;
6858                 }
6859
6860                 cond_resched();
6861         }
6862
6863         return ret;
6864 }
6865
6866 static struct extent_map *create_pinned_em(struct inode *inode, u64 start,
6867                                            u64 len, u64 orig_start,
6868                                            u64 block_start, u64 block_len,
6869                                            u64 orig_block_len, u64 ram_bytes,
6870                                            int type)
6871 {
6872         struct extent_map_tree *em_tree;
6873         struct extent_map *em;
6874         struct btrfs_root *root = BTRFS_I(inode)->root;
6875         int ret;
6876
6877         em_tree = &BTRFS_I(inode)->extent_tree;
6878         em = alloc_extent_map();
6879         if (!em)
6880                 return ERR_PTR(-ENOMEM);
6881
6882         em->start = start;
6883         em->orig_start = orig_start;
6884         em->mod_start = start;
6885         em->mod_len = len;
6886         em->len = len;
6887         em->block_len = block_len;
6888         em->block_start = block_start;
6889         em->bdev = root->fs_info->fs_devices->latest_bdev;
6890         em->orig_block_len = orig_block_len;
6891         em->ram_bytes = ram_bytes;
6892         em->generation = -1;
6893         set_bit(EXTENT_FLAG_PINNED, &em->flags);
6894         if (type == BTRFS_ORDERED_PREALLOC)
6895                 set_bit(EXTENT_FLAG_FILLING, &em->flags);
6896
6897         do {
6898                 btrfs_drop_extent_cache(inode, em->start,
6899                                 em->start + em->len - 1, 0);
6900                 write_lock(&em_tree->lock);
6901                 ret = add_extent_mapping(em_tree, em, 1);
6902                 write_unlock(&em_tree->lock);
6903         } while (ret == -EEXIST);
6904
6905         if (ret) {
6906                 free_extent_map(em);
6907                 return ERR_PTR(ret);
6908         }
6909
6910         return em;
6911 }
6912
6913
6914 static int btrfs_get_blocks_direct(struct inode *inode, sector_t iblock,
6915                                    struct buffer_head *bh_result, int create)
6916 {
6917         struct extent_map *em;
6918         struct btrfs_root *root = BTRFS_I(inode)->root;
6919         struct extent_state *cached_state = NULL;
6920         u64 start = iblock << inode->i_blkbits;
6921         u64 lockstart, lockend;
6922         u64 len = bh_result->b_size;
6923         int unlock_bits = EXTENT_LOCKED;
6924         int ret = 0;
6925
6926         if (create)
6927                 unlock_bits |= EXTENT_DELALLOC | EXTENT_DIRTY;
6928         else
6929                 len = min_t(u64, len, root->sectorsize);
6930
6931         lockstart = start;
6932         lockend = start + len - 1;
6933
6934         /*
6935          * If this errors out it's because we couldn't invalidate pagecache for
6936          * this range and we need to fallback to buffered.
6937          */
6938         if (lock_extent_direct(inode, lockstart, lockend, &cached_state, create))
6939                 return -ENOTBLK;
6940
6941         em = btrfs_get_extent(inode, NULL, 0, start, len, 0);
6942         if (IS_ERR(em)) {
6943                 ret = PTR_ERR(em);
6944                 goto unlock_err;
6945         }
6946
6947         /*
6948          * Ok for INLINE and COMPRESSED extents we need to fallback on buffered
6949          * io.  INLINE is special, and we could probably kludge it in here, but
6950          * it's still buffered so for safety lets just fall back to the generic
6951          * buffered path.
6952          *
6953          * For COMPRESSED we _have_ to read the entire extent in so we can
6954          * decompress it, so there will be buffering required no matter what we
6955          * do, so go ahead and fallback to buffered.
6956          *
6957          * We return -ENOTBLK because thats what makes DIO go ahead and go back
6958          * to buffered IO.  Don't blame me, this is the price we pay for using
6959          * the generic code.
6960          */
6961         if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags) ||
6962             em->block_start == EXTENT_MAP_INLINE) {
6963                 free_extent_map(em);
6964                 ret = -ENOTBLK;
6965                 goto unlock_err;
6966         }
6967
6968         /* Just a good old fashioned hole, return */
6969         if (!create && (em->block_start == EXTENT_MAP_HOLE ||
6970                         test_bit(EXTENT_FLAG_PREALLOC, &em->flags))) {
6971                 free_extent_map(em);
6972                 goto unlock_err;
6973         }
6974
6975         /*
6976          * We don't allocate a new extent in the following cases
6977          *
6978          * 1) The inode is marked as NODATACOW.  In this case we'll just use the
6979          * existing extent.
6980          * 2) The extent is marked as PREALLOC.  We're good to go here and can
6981          * just use the extent.
6982          *
6983          */
6984         if (!create) {
6985                 len = min(len, em->len - (start - em->start));
6986                 lockstart = start + len;
6987                 goto unlock;
6988         }
6989
6990         if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags) ||
6991             ((BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW) &&
6992              em->block_start != EXTENT_MAP_HOLE)) {
6993                 int type;
6994                 int ret;
6995                 u64 block_start, orig_start, orig_block_len, ram_bytes;
6996
6997                 if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
6998                         type = BTRFS_ORDERED_PREALLOC;
6999                 else
7000                         type = BTRFS_ORDERED_NOCOW;
7001                 len = min(len, em->len - (start - em->start));
7002                 block_start = em->block_start + (start - em->start);
7003
7004                 if (can_nocow_extent(inode, start, &len, &orig_start,
7005                                      &orig_block_len, &ram_bytes) == 1) {
7006                         if (type == BTRFS_ORDERED_PREALLOC) {
7007                                 free_extent_map(em);
7008                                 em = create_pinned_em(inode, start, len,
7009                                                        orig_start,
7010                                                        block_start, len,
7011                                                        orig_block_len,
7012                                                        ram_bytes, type);
7013                                 if (IS_ERR(em))
7014                                         goto unlock_err;
7015                         }
7016
7017                         ret = btrfs_add_ordered_extent_dio(inode, start,
7018                                            block_start, len, len, type);
7019                         if (ret) {
7020                                 free_extent_map(em);
7021                                 goto unlock_err;
7022                         }
7023                         goto unlock;
7024                 }
7025         }
7026
7027         /*
7028          * this will cow the extent, reset the len in case we changed
7029          * it above
7030          */
7031         len = bh_result->b_size;
7032         free_extent_map(em);
7033         em = btrfs_new_extent_direct(inode, start, len);
7034         if (IS_ERR(em)) {
7035                 ret = PTR_ERR(em);
7036                 goto unlock_err;
7037         }
7038         len = min(len, em->len - (start - em->start));
7039 unlock:
7040         bh_result->b_blocknr = (em->block_start + (start - em->start)) >>
7041                 inode->i_blkbits;
7042         bh_result->b_size = len;
7043         bh_result->b_bdev = em->bdev;
7044         set_buffer_mapped(bh_result);
7045         if (create) {
7046                 if (!test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
7047                         set_buffer_new(bh_result);
7048
7049                 /*
7050                  * Need to update the i_size under the extent lock so buffered
7051                  * readers will get the updated i_size when we unlock.
7052                  */
7053                 if (start + len > i_size_read(inode))
7054                         i_size_write(inode, start + len);
7055
7056                 spin_lock(&BTRFS_I(inode)->lock);
7057                 BTRFS_I(inode)->outstanding_extents++;
7058                 spin_unlock(&BTRFS_I(inode)->lock);
7059
7060                 ret = set_extent_bit(&BTRFS_I(inode)->io_tree, lockstart,
7061                                      lockstart + len - 1, EXTENT_DELALLOC, NULL,
7062                                      &cached_state, GFP_NOFS);
7063                 BUG_ON(ret);
7064         }
7065
7066         /*
7067          * In the case of write we need to clear and unlock the entire range,
7068          * in the case of read we need to unlock only the end area that we
7069          * aren't using if there is any left over space.
7070          */
7071         if (lockstart < lockend) {
7072                 clear_extent_bit(&BTRFS_I(inode)->io_tree, lockstart,
7073                                  lockend, unlock_bits, 1, 0,
7074                                  &cached_state, GFP_NOFS);
7075         } else {
7076                 free_extent_state(cached_state);
7077         }
7078
7079         free_extent_map(em);
7080
7081         return 0;
7082
7083 unlock_err:
7084         clear_extent_bit(&BTRFS_I(inode)->io_tree, lockstart, lockend,
7085                          unlock_bits, 1, 0, &cached_state, GFP_NOFS);
7086         return ret;
7087 }
7088
7089 static void btrfs_endio_direct_read(struct bio *bio, int err)
7090 {
7091         struct btrfs_dio_private *dip = bio->bi_private;
7092         struct bio_vec *bvec;
7093         struct inode *inode = dip->inode;
7094         struct btrfs_root *root = BTRFS_I(inode)->root;
7095         struct bio *dio_bio;
7096         u32 *csums = (u32 *)dip->csum;
7097         u64 start;
7098         int i;
7099
7100         start = dip->logical_offset;
7101         bio_for_each_segment_all(bvec, bio, i) {
7102                 if (!(BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)) {
7103                         struct page *page = bvec->bv_page;
7104                         char *kaddr;
7105                         u32 csum = ~(u32)0;
7106                         unsigned long flags;
7107
7108                         local_irq_save(flags);
7109                         kaddr = kmap_atomic(page);
7110                         csum = btrfs_csum_data(kaddr + bvec->bv_offset,
7111                                                csum, bvec->bv_len);
7112                         btrfs_csum_final(csum, (char *)&csum);
7113                         kunmap_atomic(kaddr);
7114                         local_irq_restore(flags);
7115
7116                         flush_dcache_page(bvec->bv_page);
7117                         if (csum != csums[i]) {
7118                                 btrfs_err(root->fs_info, "csum failed ino %llu off %llu csum %u expected csum %u",
7119                                           btrfs_ino(inode), start, csum,
7120                                           csums[i]);
7121                                 err = -EIO;
7122                         }
7123                 }
7124
7125                 start += bvec->bv_len;
7126         }
7127
7128         unlock_extent(&BTRFS_I(inode)->io_tree, dip->logical_offset,
7129                       dip->logical_offset + dip->bytes - 1);
7130         dio_bio = dip->dio_bio;
7131
7132         kfree(dip);
7133
7134         /* If we had a csum failure make sure to clear the uptodate flag */
7135         if (err)
7136                 clear_bit(BIO_UPTODATE, &dio_bio->bi_flags);
7137         dio_end_io(dio_bio, err);
7138         bio_put(bio);
7139 }
7140
7141 static void btrfs_endio_direct_write(struct bio *bio, int err)
7142 {
7143         struct btrfs_dio_private *dip = bio->bi_private;
7144         struct inode *inode = dip->inode;
7145         struct btrfs_root *root = BTRFS_I(inode)->root;
7146         struct btrfs_ordered_extent *ordered = NULL;
7147         u64 ordered_offset = dip->logical_offset;
7148         u64 ordered_bytes = dip->bytes;
7149         struct bio *dio_bio;
7150         int ret;
7151
7152         if (err)
7153                 goto out_done;
7154 again:
7155         ret = btrfs_dec_test_first_ordered_pending(inode, &ordered,
7156                                                    &ordered_offset,
7157                                                    ordered_bytes, !err);
7158         if (!ret)
7159                 goto out_test;
7160
7161         btrfs_init_work(&ordered->work, finish_ordered_fn, NULL, NULL);
7162         btrfs_queue_work(root->fs_info->endio_write_workers,
7163                          &ordered->work);
7164 out_test:
7165         /*
7166          * our bio might span multiple ordered extents.  If we haven't
7167          * completed the accounting for the whole dio, go back and try again
7168          */
7169         if (ordered_offset < dip->logical_offset + dip->bytes) {
7170                 ordered_bytes = dip->logical_offset + dip->bytes -
7171                         ordered_offset;
7172                 ordered = NULL;
7173                 goto again;
7174         }
7175 out_done:
7176         dio_bio = dip->dio_bio;
7177
7178         kfree(dip);
7179
7180         /* If we had an error make sure to clear the uptodate flag */
7181         if (err)
7182                 clear_bit(BIO_UPTODATE, &dio_bio->bi_flags);
7183         dio_end_io(dio_bio, err);
7184         bio_put(bio);
7185 }
7186
7187 static int __btrfs_submit_bio_start_direct_io(struct inode *inode, int rw,
7188                                     struct bio *bio, int mirror_num,
7189                                     unsigned long bio_flags, u64 offset)
7190 {
7191         int ret;
7192         struct btrfs_root *root = BTRFS_I(inode)->root;
7193         ret = btrfs_csum_one_bio(root, inode, bio, offset, 1);
7194         BUG_ON(ret); /* -ENOMEM */
7195         return 0;
7196 }
7197
7198 static void btrfs_end_dio_bio(struct bio *bio, int err)
7199 {
7200         struct btrfs_dio_private *dip = bio->bi_private;
7201
7202         if (err) {
7203                 btrfs_err(BTRFS_I(dip->inode)->root->fs_info,
7204                           "direct IO failed ino %llu rw %lu sector %#Lx len %u err no %d",
7205                       btrfs_ino(dip->inode), bio->bi_rw,
7206                       (unsigned long long)bio->bi_iter.bi_sector,
7207                       bio->bi_iter.bi_size, err);
7208                 dip->errors = 1;
7209
7210                 /*
7211                  * before atomic variable goto zero, we must make sure
7212                  * dip->errors is perceived to be set.
7213                  */
7214                 smp_mb__before_atomic();
7215         }
7216
7217         /* if there are more bios still pending for this dio, just exit */
7218         if (!atomic_dec_and_test(&dip->pending_bios))
7219                 goto out;
7220
7221         if (dip->errors) {
7222                 bio_io_error(dip->orig_bio);
7223         } else {
7224                 set_bit(BIO_UPTODATE, &dip->dio_bio->bi_flags);
7225                 bio_endio(dip->orig_bio, 0);
7226         }
7227 out:
7228         bio_put(bio);
7229 }
7230
7231 static struct bio *btrfs_dio_bio_alloc(struct block_device *bdev,
7232                                        u64 first_sector, gfp_t gfp_flags)
7233 {
7234         int nr_vecs = bio_get_nr_vecs(bdev);
7235         return btrfs_bio_alloc(bdev, first_sector, nr_vecs, gfp_flags);
7236 }
7237
7238 static inline int __btrfs_submit_dio_bio(struct bio *bio, struct inode *inode,
7239                                          int rw, u64 file_offset, int skip_sum,
7240                                          int async_submit)
7241 {
7242         struct btrfs_dio_private *dip = bio->bi_private;
7243         int write = rw & REQ_WRITE;
7244         struct btrfs_root *root = BTRFS_I(inode)->root;
7245         int ret;
7246
7247         if (async_submit)
7248                 async_submit = !atomic_read(&BTRFS_I(inode)->sync_writers);
7249
7250         bio_get(bio);
7251
7252         if (!write) {
7253                 ret = btrfs_bio_wq_end_io(root->fs_info, bio, 0);
7254                 if (ret)
7255                         goto err;
7256         }
7257
7258         if (skip_sum)
7259                 goto map;
7260
7261         if (write && async_submit) {
7262                 ret = btrfs_wq_submit_bio(root->fs_info,
7263                                    inode, rw, bio, 0, 0,
7264                                    file_offset,
7265                                    __btrfs_submit_bio_start_direct_io,
7266                                    __btrfs_submit_bio_done);
7267                 goto err;
7268         } else if (write) {
7269                 /*
7270                  * If we aren't doing async submit, calculate the csum of the
7271                  * bio now.
7272                  */
7273                 ret = btrfs_csum_one_bio(root, inode, bio, file_offset, 1);
7274                 if (ret)
7275                         goto err;
7276         } else if (!skip_sum) {
7277                 ret = btrfs_lookup_bio_sums_dio(root, inode, dip, bio,
7278                                                 file_offset);
7279                 if (ret)
7280                         goto err;
7281         }
7282
7283 map:
7284         ret = btrfs_map_bio(root, rw, bio, 0, async_submit);
7285 err:
7286         bio_put(bio);
7287         return ret;
7288 }
7289
7290 static int btrfs_submit_direct_hook(int rw, struct btrfs_dio_private *dip,
7291                                     int skip_sum)
7292 {
7293         struct inode *inode = dip->inode;
7294         struct btrfs_root *root = BTRFS_I(inode)->root;
7295         struct bio *bio;
7296         struct bio *orig_bio = dip->orig_bio;
7297         struct bio_vec *bvec = orig_bio->bi_io_vec;
7298         u64 start_sector = orig_bio->bi_iter.bi_sector;
7299         u64 file_offset = dip->logical_offset;
7300         u64 submit_len = 0;
7301         u64 map_length;
7302         int nr_pages = 0;
7303         int ret = 0;
7304         int async_submit = 0;
7305
7306         map_length = orig_bio->bi_iter.bi_size;
7307         ret = btrfs_map_block(root->fs_info, rw, start_sector << 9,
7308                               &map_length, NULL, 0);
7309         if (ret) {
7310                 bio_put(orig_bio);
7311                 return -EIO;
7312         }
7313
7314         if (map_length >= orig_bio->bi_iter.bi_size) {
7315                 bio = orig_bio;
7316                 goto submit;
7317         }
7318
7319         /* async crcs make it difficult to collect full stripe writes. */
7320         if (btrfs_get_alloc_profile(root, 1) &
7321             (BTRFS_BLOCK_GROUP_RAID5 | BTRFS_BLOCK_GROUP_RAID6))
7322                 async_submit = 0;
7323         else
7324                 async_submit = 1;
7325
7326         bio = btrfs_dio_bio_alloc(orig_bio->bi_bdev, start_sector, GFP_NOFS);
7327         if (!bio)
7328                 return -ENOMEM;
7329         bio->bi_private = dip;
7330         bio->bi_end_io = btrfs_end_dio_bio;
7331         atomic_inc(&dip->pending_bios);
7332
7333         while (bvec <= (orig_bio->bi_io_vec + orig_bio->bi_vcnt - 1)) {
7334                 if (unlikely(map_length < submit_len + bvec->bv_len ||
7335                     bio_add_page(bio, bvec->bv_page, bvec->bv_len,
7336                                  bvec->bv_offset) < bvec->bv_len)) {
7337                         /*
7338                          * inc the count before we submit the bio so
7339                          * we know the end IO handler won't happen before
7340                          * we inc the count. Otherwise, the dip might get freed
7341                          * before we're done setting it up
7342                          */
7343                         atomic_inc(&dip->pending_bios);
7344                         ret = __btrfs_submit_dio_bio(bio, inode, rw,
7345                                                      file_offset, skip_sum,
7346                                                      async_submit);
7347                         if (ret) {
7348                                 bio_put(bio);
7349                                 atomic_dec(&dip->pending_bios);
7350                                 goto out_err;
7351                         }
7352
7353                         start_sector += submit_len >> 9;
7354                         file_offset += submit_len;
7355
7356                         submit_len = 0;
7357                         nr_pages = 0;
7358
7359                         bio = btrfs_dio_bio_alloc(orig_bio->bi_bdev,
7360                                                   start_sector, GFP_NOFS);
7361                         if (!bio)
7362                                 goto out_err;
7363                         bio->bi_private = dip;
7364                         bio->bi_end_io = btrfs_end_dio_bio;
7365
7366                         map_length = orig_bio->bi_iter.bi_size;
7367                         ret = btrfs_map_block(root->fs_info, rw,
7368                                               start_sector << 9,
7369                                               &map_length, NULL, 0);
7370                         if (ret) {
7371                                 bio_put(bio);
7372                                 goto out_err;
7373                         }
7374                 } else {
7375                         submit_len += bvec->bv_len;
7376                         nr_pages++;
7377                         bvec++;
7378                 }
7379         }
7380
7381 submit:
7382         ret = __btrfs_submit_dio_bio(bio, inode, rw, file_offset, skip_sum,
7383                                      async_submit);
7384         if (!ret)
7385                 return 0;
7386
7387         bio_put(bio);
7388 out_err:
7389         dip->errors = 1;
7390         /*
7391          * before atomic variable goto zero, we must
7392          * make sure dip->errors is perceived to be set.
7393          */
7394         smp_mb__before_atomic();
7395         if (atomic_dec_and_test(&dip->pending_bios))
7396                 bio_io_error(dip->orig_bio);
7397
7398         /* bio_end_io() will handle error, so we needn't return it */
7399         return 0;
7400 }
7401
7402 static void btrfs_submit_direct(int rw, struct bio *dio_bio,
7403                                 struct inode *inode, loff_t file_offset)
7404 {
7405         struct btrfs_root *root = BTRFS_I(inode)->root;
7406         struct btrfs_dio_private *dip;
7407         struct bio *io_bio;
7408         int skip_sum;
7409         int sum_len;
7410         int write = rw & REQ_WRITE;
7411         int ret = 0;
7412         u16 csum_size;
7413
7414         skip_sum = BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM;
7415
7416         io_bio = btrfs_bio_clone(dio_bio, GFP_NOFS);
7417         if (!io_bio) {
7418                 ret = -ENOMEM;
7419                 goto free_ordered;
7420         }
7421
7422         if (!skip_sum && !write) {
7423                 csum_size = btrfs_super_csum_size(root->fs_info->super_copy);
7424                 sum_len = dio_bio->bi_iter.bi_size >>
7425                         inode->i_sb->s_blocksize_bits;
7426                 sum_len *= csum_size;
7427         } else {
7428                 sum_len = 0;
7429         }
7430
7431         dip = kmalloc(sizeof(*dip) + sum_len, GFP_NOFS);
7432         if (!dip) {
7433                 ret = -ENOMEM;
7434                 goto free_io_bio;
7435         }
7436
7437         dip->private = dio_bio->bi_private;
7438         dip->inode = inode;
7439         dip->logical_offset = file_offset;
7440         dip->bytes = dio_bio->bi_iter.bi_size;
7441         dip->disk_bytenr = (u64)dio_bio->bi_iter.bi_sector << 9;
7442         io_bio->bi_private = dip;
7443         dip->errors = 0;
7444         dip->orig_bio = io_bio;
7445         dip->dio_bio = dio_bio;
7446         atomic_set(&dip->pending_bios, 0);
7447
7448         if (write)
7449                 io_bio->bi_end_io = btrfs_endio_direct_write;
7450         else
7451                 io_bio->bi_end_io = btrfs_endio_direct_read;
7452
7453         ret = btrfs_submit_direct_hook(rw, dip, skip_sum);
7454         if (!ret)
7455                 return;
7456
7457 free_io_bio:
7458         bio_put(io_bio);
7459
7460 free_ordered:
7461         /*
7462          * If this is a write, we need to clean up the reserved space and kill
7463          * the ordered extent.
7464          */
7465         if (write) {
7466                 struct btrfs_ordered_extent *ordered;
7467                 ordered = btrfs_lookup_ordered_extent(inode, file_offset);
7468                 if (!test_bit(BTRFS_ORDERED_PREALLOC, &ordered->flags) &&
7469                     !test_bit(BTRFS_ORDERED_NOCOW, &ordered->flags))
7470                         btrfs_free_reserved_extent(root, ordered->start,
7471                                                    ordered->disk_len, 1);
7472                 btrfs_put_ordered_extent(ordered);
7473                 btrfs_put_ordered_extent(ordered);
7474         }
7475         bio_endio(dio_bio, ret);
7476 }
7477
7478 static ssize_t check_direct_IO(struct btrfs_root *root, int rw, struct kiocb *iocb,
7479                         const struct iov_iter *iter, loff_t offset)
7480 {
7481         int seg;
7482         int i;
7483         unsigned blocksize_mask = root->sectorsize - 1;
7484         ssize_t retval = -EINVAL;
7485
7486         if (offset & blocksize_mask)
7487                 goto out;
7488
7489         if (iov_iter_alignment(iter) & blocksize_mask)
7490                 goto out;
7491
7492         /* If this is a write we don't need to check anymore */
7493         if (rw & WRITE)
7494                 return 0;
7495         /*
7496          * Check to make sure we don't have duplicate iov_base's in this
7497          * iovec, if so return EINVAL, otherwise we'll get csum errors
7498          * when reading back.
7499          */
7500         for (seg = 0; seg < iter->nr_segs; seg++) {
7501                 for (i = seg + 1; i < iter->nr_segs; i++) {
7502                         if (iter->iov[seg].iov_base == iter->iov[i].iov_base)
7503                                 goto out;
7504                 }
7505         }
7506         retval = 0;
7507 out:
7508         return retval;
7509 }
7510
7511 static ssize_t btrfs_direct_IO(int rw, struct kiocb *iocb,
7512                         struct iov_iter *iter, loff_t offset)
7513 {
7514         struct file *file = iocb->ki_filp;
7515         struct inode *inode = file->f_mapping->host;
7516         size_t count = 0;
7517         int flags = 0;
7518         bool wakeup = true;
7519         bool relock = false;
7520         ssize_t ret;
7521
7522         if (check_direct_IO(BTRFS_I(inode)->root, rw, iocb, iter, offset))
7523                 return 0;
7524
7525         atomic_inc(&inode->i_dio_count);
7526         smp_mb__after_atomic();
7527
7528         /*
7529          * The generic stuff only does filemap_write_and_wait_range, which
7530          * isn't enough if we've written compressed pages to this area, so
7531          * we need to flush the dirty pages again to make absolutely sure
7532          * that any outstanding dirty pages are on disk.
7533          */
7534         count = iov_iter_count(iter);
7535         if (test_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
7536                      &BTRFS_I(inode)->runtime_flags))
7537                 filemap_fdatawrite_range(inode->i_mapping, offset, count);
7538
7539         if (rw & WRITE) {
7540                 /*
7541                  * If the write DIO is beyond the EOF, we need update
7542                  * the isize, but it is protected by i_mutex. So we can
7543                  * not unlock the i_mutex at this case.
7544                  */
7545                 if (offset + count <= inode->i_size) {
7546                         mutex_unlock(&inode->i_mutex);
7547                         relock = true;
7548                 }
7549                 ret = btrfs_delalloc_reserve_space(inode, count);
7550                 if (ret)
7551                         goto out;
7552         } else if (unlikely(test_bit(BTRFS_INODE_READDIO_NEED_LOCK,
7553                                      &BTRFS_I(inode)->runtime_flags))) {
7554                 inode_dio_done(inode);
7555                 flags = DIO_LOCKING | DIO_SKIP_HOLES;
7556                 wakeup = false;
7557         }
7558
7559         ret = __blockdev_direct_IO(rw, iocb, inode,
7560                         BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev,
7561                         iter, offset, btrfs_get_blocks_direct, NULL,
7562                         btrfs_submit_direct, flags);
7563         if (rw & WRITE) {
7564                 if (ret < 0 && ret != -EIOCBQUEUED)
7565                         btrfs_delalloc_release_space(inode, count);
7566                 else if (ret >= 0 && (size_t)ret < count)
7567                         btrfs_delalloc_release_space(inode,
7568                                                      count - (size_t)ret);
7569                 else
7570                         btrfs_delalloc_release_metadata(inode, 0);
7571         }
7572 out:
7573         if (wakeup)
7574                 inode_dio_done(inode);
7575         if (relock)
7576                 mutex_lock(&inode->i_mutex);
7577
7578         return ret;
7579 }
7580
7581 #define BTRFS_FIEMAP_FLAGS      (FIEMAP_FLAG_SYNC)
7582
7583 static int btrfs_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
7584                 __u64 start, __u64 len)
7585 {
7586         int     ret;
7587
7588         ret = fiemap_check_flags(fieinfo, BTRFS_FIEMAP_FLAGS);
7589         if (ret)
7590                 return ret;
7591
7592         return extent_fiemap(inode, fieinfo, start, len, btrfs_get_extent_fiemap);
7593 }
7594
7595 int btrfs_readpage(struct file *file, struct page *page)
7596 {
7597         struct extent_io_tree *tree;
7598         tree = &BTRFS_I(page->mapping->host)->io_tree;
7599         return extent_read_full_page(tree, page, btrfs_get_extent, 0);
7600 }
7601
7602 static int btrfs_writepage(struct page *page, struct writeback_control *wbc)
7603 {
7604         struct extent_io_tree *tree;
7605
7606
7607         if (current->flags & PF_MEMALLOC) {
7608                 redirty_page_for_writepage(wbc, page);
7609                 unlock_page(page);
7610                 return 0;
7611         }
7612         tree = &BTRFS_I(page->mapping->host)->io_tree;
7613         return extent_write_full_page(tree, page, btrfs_get_extent, wbc);
7614 }
7615
7616 static int btrfs_writepages(struct address_space *mapping,
7617                             struct writeback_control *wbc)
7618 {
7619         struct extent_io_tree *tree;
7620
7621         tree = &BTRFS_I(mapping->host)->io_tree;
7622         return extent_writepages(tree, mapping, btrfs_get_extent, wbc);
7623 }
7624
7625 static int
7626 btrfs_readpages(struct file *file, struct address_space *mapping,
7627                 struct list_head *pages, unsigned nr_pages)
7628 {
7629         struct extent_io_tree *tree;
7630         tree = &BTRFS_I(mapping->host)->io_tree;
7631         return extent_readpages(tree, mapping, pages, nr_pages,
7632                                 btrfs_get_extent);
7633 }
7634 static int __btrfs_releasepage(struct page *page, gfp_t gfp_flags)
7635 {
7636         struct extent_io_tree *tree;
7637         struct extent_map_tree *map;
7638         int ret;
7639
7640         tree = &BTRFS_I(page->mapping->host)->io_tree;
7641         map = &BTRFS_I(page->mapping->host)->extent_tree;
7642         ret = try_release_extent_mapping(map, tree, page, gfp_flags);
7643         if (ret == 1) {
7644                 ClearPagePrivate(page);
7645                 set_page_private(page, 0);
7646                 page_cache_release(page);
7647         }
7648         return ret;
7649 }
7650
7651 static int btrfs_releasepage(struct page *page, gfp_t gfp_flags)
7652 {
7653         if (PageWriteback(page) || PageDirty(page))
7654                 return 0;
7655         return __btrfs_releasepage(page, gfp_flags & GFP_NOFS);
7656 }
7657
7658 static void btrfs_invalidatepage(struct page *page, unsigned int offset,
7659                                  unsigned int length)
7660 {
7661         struct inode *inode = page->mapping->host;
7662         struct extent_io_tree *tree;
7663         struct btrfs_ordered_extent *ordered;
7664         struct extent_state *cached_state = NULL;
7665         u64 page_start = page_offset(page);
7666         u64 page_end = page_start + PAGE_CACHE_SIZE - 1;
7667         int inode_evicting = inode->i_state & I_FREEING;
7668
7669         /*
7670          * we have the page locked, so new writeback can't start,
7671          * and the dirty bit won't be cleared while we are here.
7672          *
7673          * Wait for IO on this page so that we can safely clear
7674          * the PagePrivate2 bit and do ordered accounting
7675          */
7676         wait_on_page_writeback(page);
7677
7678         tree = &BTRFS_I(inode)->io_tree;
7679         if (offset) {
7680                 btrfs_releasepage(page, GFP_NOFS);
7681                 return;
7682         }
7683
7684         if (!inode_evicting)
7685                 lock_extent_bits(tree, page_start, page_end, 0, &cached_state);
7686         ordered = btrfs_lookup_ordered_extent(inode, page_start);
7687         if (ordered) {
7688                 /*
7689                  * IO on this page will never be started, so we need
7690                  * to account for any ordered extents now
7691                  */
7692                 if (!inode_evicting)
7693                         clear_extent_bit(tree, page_start, page_end,
7694                                          EXTENT_DIRTY | EXTENT_DELALLOC |
7695                                          EXTENT_LOCKED | EXTENT_DO_ACCOUNTING |
7696                                          EXTENT_DEFRAG, 1, 0, &cached_state,
7697                                          GFP_NOFS);
7698                 /*
7699                  * whoever cleared the private bit is responsible
7700                  * for the finish_ordered_io
7701                  */
7702                 if (TestClearPagePrivate2(page)) {
7703                         struct btrfs_ordered_inode_tree *tree;
7704                         u64 new_len;
7705
7706                         tree = &BTRFS_I(inode)->ordered_tree;
7707
7708                         spin_lock_irq(&tree->lock);
7709                         set_bit(BTRFS_ORDERED_TRUNCATED, &ordered->flags);
7710                         new_len = page_start - ordered->file_offset;
7711                         if (new_len < ordered->truncated_len)
7712                                 ordered->truncated_len = new_len;
7713                         spin_unlock_irq(&tree->lock);
7714
7715                         if (btrfs_dec_test_ordered_pending(inode, &ordered,
7716                                                            page_start,
7717                                                            PAGE_CACHE_SIZE, 1))
7718                                 btrfs_finish_ordered_io(ordered);
7719                 }
7720                 btrfs_put_ordered_extent(ordered);
7721                 if (!inode_evicting) {
7722                         cached_state = NULL;
7723                         lock_extent_bits(tree, page_start, page_end, 0,
7724                                          &cached_state);
7725                 }
7726         }
7727
7728         if (!inode_evicting) {
7729                 clear_extent_bit(tree, page_start, page_end,
7730                                  EXTENT_LOCKED | EXTENT_DIRTY |
7731                                  EXTENT_DELALLOC | EXTENT_DO_ACCOUNTING |
7732                                  EXTENT_DEFRAG, 1, 1,
7733                                  &cached_state, GFP_NOFS);
7734
7735                 __btrfs_releasepage(page, GFP_NOFS);
7736         }
7737
7738         ClearPageChecked(page);
7739         if (PagePrivate(page)) {
7740                 ClearPagePrivate(page);
7741                 set_page_private(page, 0);
7742                 page_cache_release(page);
7743         }
7744 }
7745
7746 /*
7747  * btrfs_page_mkwrite() is not allowed to change the file size as it gets
7748  * called from a page fault handler when a page is first dirtied. Hence we must
7749  * be careful to check for EOF conditions here. We set the page up correctly
7750  * for a written page which means we get ENOSPC checking when writing into
7751  * holes and correct delalloc and unwritten extent mapping on filesystems that
7752  * support these features.
7753  *
7754  * We are not allowed to take the i_mutex here so we have to play games to
7755  * protect against truncate races as the page could now be beyond EOF.  Because
7756  * vmtruncate() writes the inode size before removing pages, once we have the
7757  * page lock we can determine safely if the page is beyond EOF. If it is not
7758  * beyond EOF, then the page is guaranteed safe against truncation until we
7759  * unlock the page.
7760  */
7761 int btrfs_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
7762 {
7763         struct page *page = vmf->page;
7764         struct inode *inode = file_inode(vma->vm_file);
7765         struct btrfs_root *root = BTRFS_I(inode)->root;
7766         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
7767         struct btrfs_ordered_extent *ordered;
7768         struct extent_state *cached_state = NULL;
7769         char *kaddr;
7770         unsigned long zero_start;
7771         loff_t size;
7772         int ret;
7773         int reserved = 0;
7774         u64 page_start;
7775         u64 page_end;
7776
7777         sb_start_pagefault(inode->i_sb);
7778         ret  = btrfs_delalloc_reserve_space(inode, PAGE_CACHE_SIZE);
7779         if (!ret) {
7780                 ret = file_update_time(vma->vm_file);
7781                 reserved = 1;
7782         }
7783         if (ret) {
7784                 if (ret == -ENOMEM)
7785                         ret = VM_FAULT_OOM;
7786                 else /* -ENOSPC, -EIO, etc */
7787                         ret = VM_FAULT_SIGBUS;
7788                 if (reserved)
7789                         goto out;
7790                 goto out_noreserve;
7791         }
7792
7793         ret = VM_FAULT_NOPAGE; /* make the VM retry the fault */
7794 again:
7795         lock_page(page);
7796         size = i_size_read(inode);
7797         page_start = page_offset(page);
7798         page_end = page_start + PAGE_CACHE_SIZE - 1;
7799
7800         if ((page->mapping != inode->i_mapping) ||
7801             (page_start >= size)) {
7802                 /* page got truncated out from underneath us */
7803                 goto out_unlock;
7804         }
7805         wait_on_page_writeback(page);
7806
7807         lock_extent_bits(io_tree, page_start, page_end, 0, &cached_state);
7808         set_page_extent_mapped(page);
7809
7810         /*
7811          * we can't set the delalloc bits if there are pending ordered
7812          * extents.  Drop our locks and wait for them to finish
7813          */
7814         ordered = btrfs_lookup_ordered_extent(inode, page_start);
7815         if (ordered) {
7816                 unlock_extent_cached(io_tree, page_start, page_end,
7817                                      &cached_state, GFP_NOFS);
7818                 unlock_page(page);
7819                 btrfs_start_ordered_extent(inode, ordered, 1);
7820                 btrfs_put_ordered_extent(ordered);
7821                 goto again;
7822         }
7823
7824         /*
7825          * XXX - page_mkwrite gets called every time the page is dirtied, even
7826          * if it was already dirty, so for space accounting reasons we need to
7827          * clear any delalloc bits for the range we are fixing to save.  There
7828          * is probably a better way to do this, but for now keep consistent with
7829          * prepare_pages in the normal write path.
7830          */
7831         clear_extent_bit(&BTRFS_I(inode)->io_tree, page_start, page_end,
7832                           EXTENT_DIRTY | EXTENT_DELALLOC |
7833                           EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG,
7834                           0, 0, &cached_state, GFP_NOFS);
7835
7836         ret = btrfs_set_extent_delalloc(inode, page_start, page_end,
7837                                         &cached_state);
7838         if (ret) {
7839                 unlock_extent_cached(io_tree, page_start, page_end,
7840                                      &cached_state, GFP_NOFS);
7841                 ret = VM_FAULT_SIGBUS;
7842                 goto out_unlock;
7843         }
7844         ret = 0;
7845
7846         /* page is wholly or partially inside EOF */
7847         if (page_start + PAGE_CACHE_SIZE > size)
7848                 zero_start = size & ~PAGE_CACHE_MASK;
7849         else
7850                 zero_start = PAGE_CACHE_SIZE;
7851
7852         if (zero_start != PAGE_CACHE_SIZE) {
7853                 kaddr = kmap(page);
7854                 memset(kaddr + zero_start, 0, PAGE_CACHE_SIZE - zero_start);
7855                 flush_dcache_page(page);
7856                 kunmap(page);
7857         }
7858         ClearPageChecked(page);
7859         set_page_dirty(page);
7860         SetPageUptodate(page);
7861
7862         BTRFS_I(inode)->last_trans = root->fs_info->generation;
7863         BTRFS_I(inode)->last_sub_trans = BTRFS_I(inode)->root->log_transid;
7864         BTRFS_I(inode)->last_log_commit = BTRFS_I(inode)->root->last_log_commit;
7865
7866         unlock_extent_cached(io_tree, page_start, page_end, &cached_state, GFP_NOFS);
7867
7868 out_unlock:
7869         if (!ret) {
7870                 sb_end_pagefault(inode->i_sb);
7871                 return VM_FAULT_LOCKED;
7872         }
7873         unlock_page(page);
7874 out:
7875         btrfs_delalloc_release_space(inode, PAGE_CACHE_SIZE);
7876 out_noreserve:
7877         sb_end_pagefault(inode->i_sb);
7878         return ret;
7879 }
7880
7881 static int btrfs_truncate(struct inode *inode)
7882 {
7883         struct btrfs_root *root = BTRFS_I(inode)->root;
7884         struct btrfs_block_rsv *rsv;
7885         int ret = 0;
7886         int err = 0;
7887         struct btrfs_trans_handle *trans;
7888         u64 mask = root->sectorsize - 1;
7889         u64 min_size = btrfs_calc_trunc_metadata_size(root, 1);
7890
7891         ret = btrfs_wait_ordered_range(inode, inode->i_size & (~mask),
7892                                        (u64)-1);
7893         if (ret)
7894                 return ret;
7895
7896         /*
7897          * Yes ladies and gentelment, this is indeed ugly.  The fact is we have
7898          * 3 things going on here
7899          *
7900          * 1) We need to reserve space for our orphan item and the space to
7901          * delete our orphan item.  Lord knows we don't want to have a dangling
7902          * orphan item because we didn't reserve space to remove it.
7903          *
7904          * 2) We need to reserve space to update our inode.
7905          *
7906          * 3) We need to have something to cache all the space that is going to
7907          * be free'd up by the truncate operation, but also have some slack
7908          * space reserved in case it uses space during the truncate (thank you
7909          * very much snapshotting).
7910          *
7911          * And we need these to all be seperate.  The fact is we can use alot of
7912          * space doing the truncate, and we have no earthly idea how much space
7913          * we will use, so we need the truncate reservation to be seperate so it
7914          * doesn't end up using space reserved for updating the inode or
7915          * removing the orphan item.  We also need to be able to stop the
7916          * transaction and start a new one, which means we need to be able to
7917          * update the inode several times, and we have no idea of knowing how
7918          * many times that will be, so we can't just reserve 1 item for the
7919          * entirety of the opration, so that has to be done seperately as well.
7920          * Then there is the orphan item, which does indeed need to be held on
7921          * to for the whole operation, and we need nobody to touch this reserved
7922          * space except the orphan code.
7923          *
7924          * So that leaves us with
7925          *
7926          * 1) root->orphan_block_rsv - for the orphan deletion.
7927          * 2) rsv - for the truncate reservation, which we will steal from the
7928          * transaction reservation.
7929          * 3) fs_info->trans_block_rsv - this will have 1 items worth left for
7930          * updating the inode.
7931          */
7932         rsv = btrfs_alloc_block_rsv(root, BTRFS_BLOCK_RSV_TEMP);
7933         if (!rsv)
7934                 return -ENOMEM;
7935         rsv->size = min_size;
7936         rsv->failfast = 1;
7937
7938         /*
7939          * 1 for the truncate slack space
7940          * 1 for updating the inode.
7941          */
7942         trans = btrfs_start_transaction(root, 2);
7943         if (IS_ERR(trans)) {
7944                 err = PTR_ERR(trans);
7945                 goto out;
7946         }
7947
7948         /* Migrate the slack space for the truncate to our reserve */
7949         ret = btrfs_block_rsv_migrate(&root->fs_info->trans_block_rsv, rsv,
7950                                       min_size);
7951         BUG_ON(ret);
7952
7953         /*
7954          * So if we truncate and then write and fsync we normally would just
7955          * write the extents that changed, which is a problem if we need to
7956          * first truncate that entire inode.  So set this flag so we write out
7957          * all of the extents in the inode to the sync log so we're completely
7958          * safe.
7959          */
7960         set_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &BTRFS_I(inode)->runtime_flags);
7961         trans->block_rsv = rsv;
7962
7963         while (1) {
7964                 ret = btrfs_truncate_inode_items(trans, root, inode,
7965                                                  inode->i_size,
7966                                                  BTRFS_EXTENT_DATA_KEY);
7967                 if (ret != -ENOSPC) {
7968                         err = ret;
7969                         break;
7970                 }
7971
7972                 trans->block_rsv = &root->fs_info->trans_block_rsv;
7973                 ret = btrfs_update_inode(trans, root, inode);
7974                 if (ret) {
7975                         err = ret;
7976                         break;
7977                 }
7978
7979                 btrfs_end_transaction(trans, root);
7980                 btrfs_btree_balance_dirty(root);
7981
7982                 trans = btrfs_start_transaction(root, 2);
7983                 if (IS_ERR(trans)) {
7984                         ret = err = PTR_ERR(trans);
7985                         trans = NULL;
7986                         break;
7987                 }
7988
7989                 ret = btrfs_block_rsv_migrate(&root->fs_info->trans_block_rsv,
7990                                               rsv, min_size);
7991                 BUG_ON(ret);    /* shouldn't happen */
7992                 trans->block_rsv = rsv;
7993         }
7994
7995         if (ret == 0 && inode->i_nlink > 0) {
7996                 trans->block_rsv = root->orphan_block_rsv;
7997                 ret = btrfs_orphan_del(trans, inode);
7998                 if (ret)
7999                         err = ret;
8000         }
8001
8002         if (trans) {
8003                 trans->block_rsv = &root->fs_info->trans_block_rsv;
8004                 ret = btrfs_update_inode(trans, root, inode);
8005                 if (ret && !err)
8006                         err = ret;
8007
8008                 ret = btrfs_end_transaction(trans, root);
8009                 btrfs_btree_balance_dirty(root);
8010         }
8011
8012 out:
8013         btrfs_free_block_rsv(root, rsv);
8014
8015         if (ret && !err)
8016                 err = ret;
8017
8018         return err;
8019 }
8020
8021 /*
8022  * create a new subvolume directory/inode (helper for the ioctl).
8023  */
8024 int btrfs_create_subvol_root(struct btrfs_trans_handle *trans,
8025                              struct btrfs_root *new_root,
8026                              struct btrfs_root *parent_root,
8027                              u64 new_dirid)
8028 {
8029         struct inode *inode;
8030         int err;
8031         u64 index = 0;
8032
8033         inode = btrfs_new_inode(trans, new_root, NULL, "..", 2,
8034                                 new_dirid, new_dirid,
8035                                 S_IFDIR | (~current_umask() & S_IRWXUGO),
8036                                 &index);
8037         if (IS_ERR(inode))
8038                 return PTR_ERR(inode);
8039         inode->i_op = &btrfs_dir_inode_operations;
8040         inode->i_fop = &btrfs_dir_file_operations;
8041
8042         set_nlink(inode, 1);
8043         btrfs_i_size_write(inode, 0);
8044
8045         err = btrfs_subvol_inherit_props(trans, new_root, parent_root);
8046         if (err)
8047                 btrfs_err(new_root->fs_info,
8048                           "error inheriting subvolume %llu properties: %d",
8049                           new_root->root_key.objectid, err);
8050
8051         err = btrfs_update_inode(trans, new_root, inode);
8052
8053         iput(inode);
8054         return err;
8055 }
8056
8057 struct inode *btrfs_alloc_inode(struct super_block *sb)
8058 {
8059         struct btrfs_inode *ei;
8060         struct inode *inode;
8061
8062         ei = kmem_cache_alloc(btrfs_inode_cachep, GFP_NOFS);
8063         if (!ei)
8064                 return NULL;
8065
8066         ei->root = NULL;
8067         ei->generation = 0;
8068         ei->last_trans = 0;
8069         ei->last_sub_trans = 0;
8070         ei->logged_trans = 0;
8071         ei->delalloc_bytes = 0;
8072         ei->disk_i_size = 0;
8073         ei->flags = 0;
8074         ei->csum_bytes = 0;
8075         ei->index_cnt = (u64)-1;
8076         ei->dir_index = 0;
8077         ei->last_unlink_trans = 0;
8078         ei->last_log_commit = 0;
8079
8080         spin_lock_init(&ei->lock);
8081         ei->outstanding_extents = 0;
8082         ei->reserved_extents = 0;
8083
8084         ei->runtime_flags = 0;
8085         ei->force_compress = BTRFS_COMPRESS_NONE;
8086
8087         ei->delayed_node = NULL;
8088
8089         inode = &ei->vfs_inode;
8090         extent_map_tree_init(&ei->extent_tree);
8091         extent_io_tree_init(&ei->io_tree, &inode->i_data);
8092         extent_io_tree_init(&ei->io_failure_tree, &inode->i_data);
8093         ei->io_tree.track_uptodate = 1;
8094         ei->io_failure_tree.track_uptodate = 1;
8095         atomic_set(&ei->sync_writers, 0);
8096         mutex_init(&ei->log_mutex);
8097         mutex_init(&ei->delalloc_mutex);
8098         btrfs_ordered_inode_tree_init(&ei->ordered_tree);
8099         INIT_LIST_HEAD(&ei->delalloc_inodes);
8100         RB_CLEAR_NODE(&ei->rb_node);
8101
8102         return inode;
8103 }
8104
8105 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
8106 void btrfs_test_destroy_inode(struct inode *inode)
8107 {
8108         btrfs_drop_extent_cache(inode, 0, (u64)-1, 0);
8109         kmem_cache_free(btrfs_inode_cachep, BTRFS_I(inode));
8110 }
8111 #endif
8112
8113 static void btrfs_i_callback(struct rcu_head *head)
8114 {
8115         struct inode *inode = container_of(head, struct inode, i_rcu);
8116         kmem_cache_free(btrfs_inode_cachep, BTRFS_I(inode));
8117 }
8118
8119 void btrfs_destroy_inode(struct inode *inode)
8120 {
8121         struct btrfs_ordered_extent *ordered;
8122         struct btrfs_root *root = BTRFS_I(inode)->root;
8123
8124         WARN_ON(!hlist_empty(&inode->i_dentry));
8125         WARN_ON(inode->i_data.nrpages);
8126         WARN_ON(BTRFS_I(inode)->outstanding_extents);
8127         WARN_ON(BTRFS_I(inode)->reserved_extents);
8128         WARN_ON(BTRFS_I(inode)->delalloc_bytes);
8129         WARN_ON(BTRFS_I(inode)->csum_bytes);
8130
8131         /*
8132          * This can happen where we create an inode, but somebody else also
8133          * created the same inode and we need to destroy the one we already
8134          * created.
8135          */
8136         if (!root)
8137                 goto free;
8138
8139         if (test_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
8140                      &BTRFS_I(inode)->runtime_flags)) {
8141                 btrfs_info(root->fs_info, "inode %llu still on the orphan list",
8142                         btrfs_ino(inode));
8143                 atomic_dec(&root->orphan_inodes);
8144         }
8145
8146         while (1) {
8147                 ordered = btrfs_lookup_first_ordered_extent(inode, (u64)-1);
8148                 if (!ordered)
8149                         break;
8150                 else {
8151                         btrfs_err(root->fs_info, "found ordered extent %llu %llu on inode cleanup",
8152                                 ordered->file_offset, ordered->len);
8153                         btrfs_remove_ordered_extent(inode, ordered);
8154                         btrfs_put_ordered_extent(ordered);
8155                         btrfs_put_ordered_extent(ordered);
8156                 }
8157         }
8158         inode_tree_del(inode);
8159         btrfs_drop_extent_cache(inode, 0, (u64)-1, 0);
8160 free:
8161         call_rcu(&inode->i_rcu, btrfs_i_callback);
8162 }
8163
8164 int btrfs_drop_inode(struct inode *inode)
8165 {
8166         struct btrfs_root *root = BTRFS_I(inode)->root;
8167
8168         if (root == NULL)
8169                 return 1;
8170
8171         /* the snap/subvol tree is on deleting */
8172         if (btrfs_root_refs(&root->root_item) == 0)
8173                 return 1;
8174         else
8175                 return generic_drop_inode(inode);
8176 }
8177
8178 static void init_once(void *foo)
8179 {
8180         struct btrfs_inode *ei = (struct btrfs_inode *) foo;
8181
8182         inode_init_once(&ei->vfs_inode);
8183 }
8184
8185 void btrfs_destroy_cachep(void)
8186 {
8187         /*
8188          * Make sure all delayed rcu free inodes are flushed before we
8189          * destroy cache.
8190          */
8191         rcu_barrier();
8192         if (btrfs_inode_cachep)
8193                 kmem_cache_destroy(btrfs_inode_cachep);
8194         if (btrfs_trans_handle_cachep)
8195                 kmem_cache_destroy(btrfs_trans_handle_cachep);
8196         if (btrfs_transaction_cachep)
8197                 kmem_cache_destroy(btrfs_transaction_cachep);
8198         if (btrfs_path_cachep)
8199                 kmem_cache_destroy(btrfs_path_cachep);
8200         if (btrfs_free_space_cachep)
8201                 kmem_cache_destroy(btrfs_free_space_cachep);
8202         if (btrfs_delalloc_work_cachep)
8203                 kmem_cache_destroy(btrfs_delalloc_work_cachep);
8204 }
8205
8206 int btrfs_init_cachep(void)
8207 {
8208         btrfs_inode_cachep = kmem_cache_create("btrfs_inode",
8209                         sizeof(struct btrfs_inode), 0,
8210                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, init_once);
8211         if (!btrfs_inode_cachep)
8212                 goto fail;
8213
8214         btrfs_trans_handle_cachep = kmem_cache_create("btrfs_trans_handle",
8215                         sizeof(struct btrfs_trans_handle), 0,
8216                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
8217         if (!btrfs_trans_handle_cachep)
8218                 goto fail;
8219
8220         btrfs_transaction_cachep = kmem_cache_create("btrfs_transaction",
8221                         sizeof(struct btrfs_transaction), 0,
8222                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
8223         if (!btrfs_transaction_cachep)
8224                 goto fail;
8225
8226         btrfs_path_cachep = kmem_cache_create("btrfs_path",
8227                         sizeof(struct btrfs_path), 0,
8228                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
8229         if (!btrfs_path_cachep)
8230                 goto fail;
8231
8232         btrfs_free_space_cachep = kmem_cache_create("btrfs_free_space",
8233                         sizeof(struct btrfs_free_space), 0,
8234                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
8235         if (!btrfs_free_space_cachep)
8236                 goto fail;
8237
8238         btrfs_delalloc_work_cachep = kmem_cache_create("btrfs_delalloc_work",
8239                         sizeof(struct btrfs_delalloc_work), 0,
8240                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD,
8241                         NULL);
8242         if (!btrfs_delalloc_work_cachep)
8243                 goto fail;
8244
8245         return 0;
8246 fail:
8247         btrfs_destroy_cachep();
8248         return -ENOMEM;
8249 }
8250
8251 static int btrfs_getattr(struct vfsmount *mnt,
8252                          struct dentry *dentry, struct kstat *stat)
8253 {
8254         u64 delalloc_bytes;
8255         struct inode *inode = dentry->d_inode;
8256         u32 blocksize = inode->i_sb->s_blocksize;
8257
8258         generic_fillattr(inode, stat);
8259         stat->dev = BTRFS_I(inode)->root->anon_dev;
8260         stat->blksize = PAGE_CACHE_SIZE;
8261
8262         spin_lock(&BTRFS_I(inode)->lock);
8263         delalloc_bytes = BTRFS_I(inode)->delalloc_bytes;
8264         spin_unlock(&BTRFS_I(inode)->lock);
8265         stat->blocks = (ALIGN(inode_get_bytes(inode), blocksize) +
8266                         ALIGN(delalloc_bytes, blocksize)) >> 9;
8267         return 0;
8268 }
8269
8270 static int btrfs_rename(struct inode *old_dir, struct dentry *old_dentry,
8271                            struct inode *new_dir, struct dentry *new_dentry)
8272 {
8273         struct btrfs_trans_handle *trans;
8274         struct btrfs_root *root = BTRFS_I(old_dir)->root;
8275         struct btrfs_root *dest = BTRFS_I(new_dir)->root;
8276         struct inode *new_inode = new_dentry->d_inode;
8277         struct inode *old_inode = old_dentry->d_inode;
8278         struct timespec ctime = CURRENT_TIME;
8279         u64 index = 0;
8280         u64 root_objectid;
8281         int ret;
8282         u64 old_ino = btrfs_ino(old_inode);
8283
8284         if (btrfs_ino(new_dir) == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)
8285                 return -EPERM;
8286
8287         /* we only allow rename subvolume link between subvolumes */
8288         if (old_ino != BTRFS_FIRST_FREE_OBJECTID && root != dest)
8289                 return -EXDEV;
8290
8291         if (old_ino == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID ||
8292             (new_inode && btrfs_ino(new_inode) == BTRFS_FIRST_FREE_OBJECTID))
8293                 return -ENOTEMPTY;
8294
8295         if (S_ISDIR(old_inode->i_mode) && new_inode &&
8296             new_inode->i_size > BTRFS_EMPTY_DIR_SIZE)
8297                 return -ENOTEMPTY;
8298
8299
8300         /* check for collisions, even if the  name isn't there */
8301         ret = btrfs_check_dir_item_collision(dest, new_dir->i_ino,
8302                              new_dentry->d_name.name,
8303                              new_dentry->d_name.len);
8304
8305         if (ret) {
8306                 if (ret == -EEXIST) {
8307                         /* we shouldn't get
8308                          * eexist without a new_inode */
8309                         if (WARN_ON(!new_inode)) {
8310                                 return ret;
8311                         }
8312                 } else {
8313                         /* maybe -EOVERFLOW */
8314                         return ret;
8315                 }
8316         }
8317         ret = 0;
8318
8319         /*
8320          * we're using rename to replace one file with another.  Start IO on it
8321          * now so  we don't add too much work to the end of the transaction
8322          */
8323         if (new_inode && S_ISREG(old_inode->i_mode) && new_inode->i_size)
8324                 filemap_flush(old_inode->i_mapping);
8325
8326         /* close the racy window with snapshot create/destroy ioctl */
8327         if (old_ino == BTRFS_FIRST_FREE_OBJECTID)
8328                 down_read(&root->fs_info->subvol_sem);
8329         /*
8330          * We want to reserve the absolute worst case amount of items.  So if
8331          * both inodes are subvols and we need to unlink them then that would
8332          * require 4 item modifications, but if they are both normal inodes it
8333          * would require 5 item modifications, so we'll assume their normal
8334          * inodes.  So 5 * 2 is 10, plus 1 for the new link, so 11 total items
8335          * should cover the worst case number of items we'll modify.
8336          */
8337         trans = btrfs_start_transaction(root, 11);
8338         if (IS_ERR(trans)) {
8339                 ret = PTR_ERR(trans);
8340                 goto out_notrans;
8341         }
8342
8343         if (dest != root)
8344                 btrfs_record_root_in_trans(trans, dest);
8345
8346         ret = btrfs_set_inode_index(new_dir, &index);
8347         if (ret)
8348                 goto out_fail;
8349
8350         BTRFS_I(old_inode)->dir_index = 0ULL;
8351         if (unlikely(old_ino == BTRFS_FIRST_FREE_OBJECTID)) {
8352                 /* force full log commit if subvolume involved. */
8353                 btrfs_set_log_full_commit(root->fs_info, trans);
8354         } else {
8355                 ret = btrfs_insert_inode_ref(trans, dest,
8356                                              new_dentry->d_name.name,
8357                                              new_dentry->d_name.len,
8358                                              old_ino,
8359                                              btrfs_ino(new_dir), index);
8360                 if (ret)
8361                         goto out_fail;
8362                 /*
8363                  * this is an ugly little race, but the rename is required
8364                  * to make sure that if we crash, the inode is either at the
8365                  * old name or the new one.  pinning the log transaction lets
8366                  * us make sure we don't allow a log commit to come in after
8367                  * we unlink the name but before we add the new name back in.
8368                  */
8369                 btrfs_pin_log_trans(root);
8370         }
8371
8372         inode_inc_iversion(old_dir);
8373         inode_inc_iversion(new_dir);
8374         inode_inc_iversion(old_inode);
8375         old_dir->i_ctime = old_dir->i_mtime = ctime;
8376         new_dir->i_ctime = new_dir->i_mtime = ctime;
8377         old_inode->i_ctime = ctime;
8378
8379         if (old_dentry->d_parent != new_dentry->d_parent)
8380                 btrfs_record_unlink_dir(trans, old_dir, old_inode, 1);
8381
8382         if (unlikely(old_ino == BTRFS_FIRST_FREE_OBJECTID)) {
8383                 root_objectid = BTRFS_I(old_inode)->root->root_key.objectid;
8384                 ret = btrfs_unlink_subvol(trans, root, old_dir, root_objectid,
8385                                         old_dentry->d_name.name,
8386                                         old_dentry->d_name.len);
8387         } else {
8388                 ret = __btrfs_unlink_inode(trans, root, old_dir,
8389                                         old_dentry->d_inode,
8390                                         old_dentry->d_name.name,
8391                                         old_dentry->d_name.len);
8392                 if (!ret)
8393                         ret = btrfs_update_inode(trans, root, old_inode);
8394         }
8395         if (ret) {
8396                 btrfs_abort_transaction(trans, root, ret);
8397                 goto out_fail;
8398         }
8399
8400         if (new_inode) {
8401                 inode_inc_iversion(new_inode);
8402                 new_inode->i_ctime = CURRENT_TIME;
8403                 if (unlikely(btrfs_ino(new_inode) ==
8404                              BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)) {
8405                         root_objectid = BTRFS_I(new_inode)->location.objectid;
8406                         ret = btrfs_unlink_subvol(trans, dest, new_dir,
8407                                                 root_objectid,
8408                                                 new_dentry->d_name.name,
8409                                                 new_dentry->d_name.len);
8410                         BUG_ON(new_inode->i_nlink == 0);
8411                 } else {
8412                         ret = btrfs_unlink_inode(trans, dest, new_dir,
8413                                                  new_dentry->d_inode,
8414                                                  new_dentry->d_name.name,
8415                                                  new_dentry->d_name.len);
8416                 }
8417                 if (!ret && new_inode->i_nlink == 0)
8418                         ret = btrfs_orphan_add(trans, new_dentry->d_inode);
8419                 if (ret) {
8420                         btrfs_abort_transaction(trans, root, ret);
8421                         goto out_fail;
8422                 }
8423         }
8424
8425         ret = btrfs_add_link(trans, new_dir, old_inode,
8426                              new_dentry->d_name.name,
8427                              new_dentry->d_name.len, 0, index);
8428         if (ret) {
8429                 btrfs_abort_transaction(trans, root, ret);
8430                 goto out_fail;
8431         }
8432
8433         if (old_inode->i_nlink == 1)
8434                 BTRFS_I(old_inode)->dir_index = index;
8435
8436         if (old_ino != BTRFS_FIRST_FREE_OBJECTID) {
8437                 struct dentry *parent = new_dentry->d_parent;
8438                 btrfs_log_new_name(trans, old_inode, old_dir, parent);
8439                 btrfs_end_log_trans(root);
8440         }
8441 out_fail:
8442         btrfs_end_transaction(trans, root);
8443 out_notrans:
8444         if (old_ino == BTRFS_FIRST_FREE_OBJECTID)
8445                 up_read(&root->fs_info->subvol_sem);
8446
8447         return ret;
8448 }
8449
8450 static void btrfs_run_delalloc_work(struct btrfs_work *work)
8451 {
8452         struct btrfs_delalloc_work *delalloc_work;
8453         struct inode *inode;
8454
8455         delalloc_work = container_of(work, struct btrfs_delalloc_work,
8456                                      work);
8457         inode = delalloc_work->inode;
8458         if (delalloc_work->wait) {
8459                 btrfs_wait_ordered_range(inode, 0, (u64)-1);
8460         } else {
8461                 filemap_flush(inode->i_mapping);
8462                 if (test_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
8463                              &BTRFS_I(inode)->runtime_flags))
8464                         filemap_flush(inode->i_mapping);
8465         }
8466
8467         if (delalloc_work->delay_iput)
8468                 btrfs_add_delayed_iput(inode);
8469         else
8470                 iput(inode);
8471         complete(&delalloc_work->completion);
8472 }
8473
8474 struct btrfs_delalloc_work *btrfs_alloc_delalloc_work(struct inode *inode,
8475                                                     int wait, int delay_iput)
8476 {
8477         struct btrfs_delalloc_work *work;
8478
8479         work = kmem_cache_zalloc(btrfs_delalloc_work_cachep, GFP_NOFS);
8480         if (!work)
8481                 return NULL;
8482
8483         init_completion(&work->completion);
8484         INIT_LIST_HEAD(&work->list);
8485         work->inode = inode;
8486         work->wait = wait;
8487         work->delay_iput = delay_iput;
8488         btrfs_init_work(&work->work, btrfs_run_delalloc_work, NULL, NULL);
8489
8490         return work;
8491 }
8492
8493 void btrfs_wait_and_free_delalloc_work(struct btrfs_delalloc_work *work)
8494 {
8495         wait_for_completion(&work->completion);
8496         kmem_cache_free(btrfs_delalloc_work_cachep, work);
8497 }
8498
8499 /*
8500  * some fairly slow code that needs optimization. This walks the list
8501  * of all the inodes with pending delalloc and forces them to disk.
8502  */
8503 static int __start_delalloc_inodes(struct btrfs_root *root, int delay_iput,
8504                                    int nr)
8505 {
8506         struct btrfs_inode *binode;
8507         struct inode *inode;
8508         struct btrfs_delalloc_work *work, *next;
8509         struct list_head works;
8510         struct list_head splice;
8511         int ret = 0;
8512
8513         INIT_LIST_HEAD(&works);
8514         INIT_LIST_HEAD(&splice);
8515
8516         mutex_lock(&root->delalloc_mutex);
8517         spin_lock(&root->delalloc_lock);
8518         list_splice_init(&root->delalloc_inodes, &splice);
8519         while (!list_empty(&splice)) {
8520                 binode = list_entry(splice.next, struct btrfs_inode,
8521                                     delalloc_inodes);
8522
8523                 list_move_tail(&binode->delalloc_inodes,
8524                                &root->delalloc_inodes);
8525                 inode = igrab(&binode->vfs_inode);
8526                 if (!inode) {
8527                         cond_resched_lock(&root->delalloc_lock);
8528                         continue;
8529                 }
8530                 spin_unlock(&root->delalloc_lock);
8531
8532                 work = btrfs_alloc_delalloc_work(inode, 0, delay_iput);
8533                 if (unlikely(!work)) {
8534                         if (delay_iput)
8535                                 btrfs_add_delayed_iput(inode);
8536                         else
8537                                 iput(inode);
8538                         ret = -ENOMEM;
8539                         goto out;
8540                 }
8541                 list_add_tail(&work->list, &works);
8542                 btrfs_queue_work(root->fs_info->flush_workers,
8543                                  &work->work);
8544                 ret++;
8545                 if (nr != -1 && ret >= nr)
8546                         goto out;
8547                 cond_resched();
8548                 spin_lock(&root->delalloc_lock);
8549         }
8550         spin_unlock(&root->delalloc_lock);
8551
8552 out:
8553         list_for_each_entry_safe(work, next, &works, list) {
8554                 list_del_init(&work->list);
8555                 btrfs_wait_and_free_delalloc_work(work);
8556         }
8557
8558         if (!list_empty_careful(&splice)) {
8559                 spin_lock(&root->delalloc_lock);
8560                 list_splice_tail(&splice, &root->delalloc_inodes);
8561                 spin_unlock(&root->delalloc_lock);
8562         }
8563         mutex_unlock(&root->delalloc_mutex);
8564         return ret;
8565 }
8566
8567 int btrfs_start_delalloc_inodes(struct btrfs_root *root, int delay_iput)
8568 {
8569         int ret;
8570
8571         if (test_bit(BTRFS_FS_STATE_ERROR, &root->fs_info->fs_state))
8572                 return -EROFS;
8573
8574         ret = __start_delalloc_inodes(root, delay_iput, -1);
8575         if (ret > 0)
8576                 ret = 0;
8577         /*
8578          * the filemap_flush will queue IO into the worker threads, but
8579          * we have to make sure the IO is actually started and that
8580          * ordered extents get created before we return
8581          */
8582         atomic_inc(&root->fs_info->async_submit_draining);
8583         while (atomic_read(&root->fs_info->nr_async_submits) ||
8584               atomic_read(&root->fs_info->async_delalloc_pages)) {
8585                 wait_event(root->fs_info->async_submit_wait,
8586                    (atomic_read(&root->fs_info->nr_async_submits) == 0 &&
8587                     atomic_read(&root->fs_info->async_delalloc_pages) == 0));
8588         }
8589         atomic_dec(&root->fs_info->async_submit_draining);
8590         return ret;
8591 }
8592
8593 int btrfs_start_delalloc_roots(struct btrfs_fs_info *fs_info, int delay_iput,
8594                                int nr)
8595 {
8596         struct btrfs_root *root;
8597         struct list_head splice;
8598         int ret;
8599
8600         if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state))
8601                 return -EROFS;
8602
8603         INIT_LIST_HEAD(&splice);
8604
8605         mutex_lock(&fs_info->delalloc_root_mutex);
8606         spin_lock(&fs_info->delalloc_root_lock);
8607         list_splice_init(&fs_info->delalloc_roots, &splice);
8608         while (!list_empty(&splice) && nr) {
8609                 root = list_first_entry(&splice, struct btrfs_root,
8610                                         delalloc_root);
8611                 root = btrfs_grab_fs_root(root);
8612                 BUG_ON(!root);
8613                 list_move_tail(&root->delalloc_root,
8614                                &fs_info->delalloc_roots);
8615                 spin_unlock(&fs_info->delalloc_root_lock);
8616
8617                 ret = __start_delalloc_inodes(root, delay_iput, nr);
8618                 btrfs_put_fs_root(root);
8619                 if (ret < 0)
8620                         goto out;
8621
8622                 if (nr != -1) {
8623                         nr -= ret;
8624                         WARN_ON(nr < 0);
8625                 }
8626                 spin_lock(&fs_info->delalloc_root_lock);
8627         }
8628         spin_unlock(&fs_info->delalloc_root_lock);
8629
8630         ret = 0;
8631         atomic_inc(&fs_info->async_submit_draining);
8632         while (atomic_read(&fs_info->nr_async_submits) ||
8633               atomic_read(&fs_info->async_delalloc_pages)) {
8634                 wait_event(fs_info->async_submit_wait,
8635                    (atomic_read(&fs_info->nr_async_submits) == 0 &&
8636                     atomic_read(&fs_info->async_delalloc_pages) == 0));
8637         }
8638         atomic_dec(&fs_info->async_submit_draining);
8639 out:
8640         if (!list_empty_careful(&splice)) {
8641                 spin_lock(&fs_info->delalloc_root_lock);
8642                 list_splice_tail(&splice, &fs_info->delalloc_roots);
8643                 spin_unlock(&fs_info->delalloc_root_lock);
8644         }
8645         mutex_unlock(&fs_info->delalloc_root_mutex);
8646         return ret;
8647 }
8648
8649 static int btrfs_symlink(struct inode *dir, struct dentry *dentry,
8650                          const char *symname)
8651 {
8652         struct btrfs_trans_handle *trans;
8653         struct btrfs_root *root = BTRFS_I(dir)->root;
8654         struct btrfs_path *path;
8655         struct btrfs_key key;
8656         struct inode *inode = NULL;
8657         int err;
8658         int drop_inode = 0;
8659         u64 objectid;
8660         u64 index = 0;
8661         int name_len;
8662         int datasize;
8663         unsigned long ptr;
8664         struct btrfs_file_extent_item *ei;
8665         struct extent_buffer *leaf;
8666
8667         name_len = strlen(symname);
8668         if (name_len > BTRFS_MAX_INLINE_DATA_SIZE(root))
8669                 return -ENAMETOOLONG;
8670
8671         /*
8672          * 2 items for inode item and ref
8673          * 2 items for dir items
8674          * 1 item for xattr if selinux is on
8675          */
8676         trans = btrfs_start_transaction(root, 5);
8677         if (IS_ERR(trans))
8678                 return PTR_ERR(trans);
8679
8680         err = btrfs_find_free_ino(root, &objectid);
8681         if (err)
8682                 goto out_unlock;
8683
8684         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
8685                                 dentry->d_name.len, btrfs_ino(dir), objectid,
8686                                 S_IFLNK|S_IRWXUGO, &index);
8687         if (IS_ERR(inode)) {
8688                 err = PTR_ERR(inode);
8689                 goto out_unlock;
8690         }
8691
8692         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
8693         if (err) {
8694                 drop_inode = 1;
8695                 goto out_unlock;
8696         }
8697
8698         /*
8699         * If the active LSM wants to access the inode during
8700         * d_instantiate it needs these. Smack checks to see
8701         * if the filesystem supports xattrs by looking at the
8702         * ops vector.
8703         */
8704         inode->i_fop = &btrfs_file_operations;
8705         inode->i_op = &btrfs_file_inode_operations;
8706
8707         err = btrfs_add_nondir(trans, dir, dentry, inode, 0, index);
8708         if (err)
8709                 drop_inode = 1;
8710         else {
8711                 inode->i_mapping->a_ops = &btrfs_aops;
8712                 inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
8713                 BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
8714         }
8715         if (drop_inode)
8716                 goto out_unlock;
8717
8718         path = btrfs_alloc_path();
8719         if (!path) {
8720                 err = -ENOMEM;
8721                 drop_inode = 1;
8722                 goto out_unlock;
8723         }
8724         key.objectid = btrfs_ino(inode);
8725         key.offset = 0;
8726         btrfs_set_key_type(&key, BTRFS_EXTENT_DATA_KEY);
8727         datasize = btrfs_file_extent_calc_inline_size(name_len);
8728         err = btrfs_insert_empty_item(trans, root, path, &key,
8729                                       datasize);
8730         if (err) {
8731                 drop_inode = 1;
8732                 btrfs_free_path(path);
8733                 goto out_unlock;
8734         }
8735         leaf = path->nodes[0];
8736         ei = btrfs_item_ptr(leaf, path->slots[0],
8737                             struct btrfs_file_extent_item);
8738         btrfs_set_file_extent_generation(leaf, ei, trans->transid);
8739         btrfs_set_file_extent_type(leaf, ei,
8740                                    BTRFS_FILE_EXTENT_INLINE);
8741         btrfs_set_file_extent_encryption(leaf, ei, 0);
8742         btrfs_set_file_extent_compression(leaf, ei, 0);
8743         btrfs_set_file_extent_other_encoding(leaf, ei, 0);
8744         btrfs_set_file_extent_ram_bytes(leaf, ei, name_len);
8745
8746         ptr = btrfs_file_extent_inline_start(ei);
8747         write_extent_buffer(leaf, symname, ptr, name_len);
8748         btrfs_mark_buffer_dirty(leaf);
8749         btrfs_free_path(path);
8750
8751         inode->i_op = &btrfs_symlink_inode_operations;
8752         inode->i_mapping->a_ops = &btrfs_symlink_aops;
8753         inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
8754         inode_set_bytes(inode, name_len);
8755         btrfs_i_size_write(inode, name_len);
8756         err = btrfs_update_inode(trans, root, inode);
8757         if (err)
8758                 drop_inode = 1;
8759
8760 out_unlock:
8761         if (!err)
8762                 d_instantiate(dentry, inode);
8763         btrfs_end_transaction(trans, root);
8764         if (drop_inode) {
8765                 inode_dec_link_count(inode);
8766                 iput(inode);
8767         }
8768         btrfs_btree_balance_dirty(root);
8769         return err;
8770 }
8771
8772 static int __btrfs_prealloc_file_range(struct inode *inode, int mode,
8773                                        u64 start, u64 num_bytes, u64 min_size,
8774                                        loff_t actual_len, u64 *alloc_hint,
8775                                        struct btrfs_trans_handle *trans)
8776 {
8777         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
8778         struct extent_map *em;
8779         struct btrfs_root *root = BTRFS_I(inode)->root;
8780         struct btrfs_key ins;
8781         u64 cur_offset = start;
8782         u64 i_size;
8783         u64 cur_bytes;
8784         int ret = 0;
8785         bool own_trans = true;
8786
8787         if (trans)
8788                 own_trans = false;
8789         while (num_bytes > 0) {
8790                 if (own_trans) {
8791                         trans = btrfs_start_transaction(root, 3);
8792                         if (IS_ERR(trans)) {
8793                                 ret = PTR_ERR(trans);
8794                                 break;
8795                         }
8796                 }
8797
8798                 cur_bytes = min(num_bytes, 256ULL * 1024 * 1024);
8799                 cur_bytes = max(cur_bytes, min_size);
8800                 ret = btrfs_reserve_extent(root, cur_bytes, min_size, 0,
8801                                            *alloc_hint, &ins, 1, 0);
8802                 if (ret) {
8803                         if (own_trans)
8804                                 btrfs_end_transaction(trans, root);
8805                         break;
8806                 }
8807
8808                 ret = insert_reserved_file_extent(trans, inode,
8809                                                   cur_offset, ins.objectid,
8810                                                   ins.offset, ins.offset,
8811                                                   ins.offset, 0, 0, 0,
8812                                                   BTRFS_FILE_EXTENT_PREALLOC);
8813                 if (ret) {
8814                         btrfs_free_reserved_extent(root, ins.objectid,
8815                                                    ins.offset, 0);
8816                         btrfs_abort_transaction(trans, root, ret);
8817                         if (own_trans)
8818                                 btrfs_end_transaction(trans, root);
8819                         break;
8820                 }
8821                 btrfs_drop_extent_cache(inode, cur_offset,
8822                                         cur_offset + ins.offset -1, 0);
8823
8824                 em = alloc_extent_map();
8825                 if (!em) {
8826                         set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
8827                                 &BTRFS_I(inode)->runtime_flags);
8828                         goto next;
8829                 }
8830
8831                 em->start = cur_offset;
8832                 em->orig_start = cur_offset;
8833                 em->len = ins.offset;
8834                 em->block_start = ins.objectid;
8835                 em->block_len = ins.offset;
8836                 em->orig_block_len = ins.offset;
8837                 em->ram_bytes = ins.offset;
8838                 em->bdev = root->fs_info->fs_devices->latest_bdev;
8839                 set_bit(EXTENT_FLAG_PREALLOC, &em->flags);
8840                 em->generation = trans->transid;
8841
8842                 while (1) {
8843                         write_lock(&em_tree->lock);
8844                         ret = add_extent_mapping(em_tree, em, 1);
8845                         write_unlock(&em_tree->lock);
8846                         if (ret != -EEXIST)
8847                                 break;
8848                         btrfs_drop_extent_cache(inode, cur_offset,
8849                                                 cur_offset + ins.offset - 1,
8850                                                 0);
8851                 }
8852                 free_extent_map(em);
8853 next:
8854                 num_bytes -= ins.offset;
8855                 cur_offset += ins.offset;
8856                 *alloc_hint = ins.objectid + ins.offset;
8857
8858                 inode_inc_iversion(inode);
8859                 inode->i_ctime = CURRENT_TIME;
8860                 BTRFS_I(inode)->flags |= BTRFS_INODE_PREALLOC;
8861                 if (!(mode & FALLOC_FL_KEEP_SIZE) &&
8862                     (actual_len > inode->i_size) &&
8863                     (cur_offset > inode->i_size)) {
8864                         if (cur_offset > actual_len)
8865                                 i_size = actual_len;
8866                         else
8867                                 i_size = cur_offset;
8868                         i_size_write(inode, i_size);
8869                         btrfs_ordered_update_i_size(inode, i_size, NULL);
8870                 }
8871
8872                 ret = btrfs_update_inode(trans, root, inode);
8873
8874                 if (ret) {
8875                         btrfs_abort_transaction(trans, root, ret);
8876                         if (own_trans)
8877                                 btrfs_end_transaction(trans, root);
8878                         break;
8879                 }
8880
8881                 if (own_trans)
8882                         btrfs_end_transaction(trans, root);
8883         }
8884         return ret;
8885 }
8886
8887 int btrfs_prealloc_file_range(struct inode *inode, int mode,
8888                               u64 start, u64 num_bytes, u64 min_size,
8889                               loff_t actual_len, u64 *alloc_hint)
8890 {
8891         return __btrfs_prealloc_file_range(inode, mode, start, num_bytes,
8892                                            min_size, actual_len, alloc_hint,
8893                                            NULL);
8894 }
8895
8896 int btrfs_prealloc_file_range_trans(struct inode *inode,
8897                                     struct btrfs_trans_handle *trans, int mode,
8898                                     u64 start, u64 num_bytes, u64 min_size,
8899                                     loff_t actual_len, u64 *alloc_hint)
8900 {
8901         return __btrfs_prealloc_file_range(inode, mode, start, num_bytes,
8902                                            min_size, actual_len, alloc_hint, trans);
8903 }
8904
8905 static int btrfs_set_page_dirty(struct page *page)
8906 {
8907         return __set_page_dirty_nobuffers(page);
8908 }
8909
8910 static int btrfs_permission(struct inode *inode, int mask)
8911 {
8912         struct btrfs_root *root = BTRFS_I(inode)->root;
8913         umode_t mode = inode->i_mode;
8914
8915         if (mask & MAY_WRITE &&
8916             (S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode))) {
8917                 if (btrfs_root_readonly(root))
8918                         return -EROFS;
8919                 if (BTRFS_I(inode)->flags & BTRFS_INODE_READONLY)
8920                         return -EACCES;
8921         }
8922         return generic_permission(inode, mask);
8923 }
8924
8925 static int btrfs_tmpfile(struct inode *dir, struct dentry *dentry, umode_t mode)
8926 {
8927         struct btrfs_trans_handle *trans;
8928         struct btrfs_root *root = BTRFS_I(dir)->root;
8929         struct inode *inode = NULL;
8930         u64 objectid;
8931         u64 index;
8932         int ret = 0;
8933
8934         /*
8935          * 5 units required for adding orphan entry
8936          */
8937         trans = btrfs_start_transaction(root, 5);
8938         if (IS_ERR(trans))
8939                 return PTR_ERR(trans);
8940
8941         ret = btrfs_find_free_ino(root, &objectid);
8942         if (ret)
8943                 goto out;
8944
8945         inode = btrfs_new_inode(trans, root, dir, NULL, 0,
8946                                 btrfs_ino(dir), objectid, mode, &index);
8947         if (IS_ERR(inode)) {
8948                 ret = PTR_ERR(inode);
8949                 inode = NULL;
8950                 goto out;
8951         }
8952
8953         ret = btrfs_init_inode_security(trans, inode, dir, NULL);
8954         if (ret)
8955                 goto out;
8956
8957         ret = btrfs_update_inode(trans, root, inode);
8958         if (ret)
8959                 goto out;
8960
8961         inode->i_fop = &btrfs_file_operations;
8962         inode->i_op = &btrfs_file_inode_operations;
8963
8964         inode->i_mapping->a_ops = &btrfs_aops;
8965         inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
8966         BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
8967
8968         ret = btrfs_orphan_add(trans, inode);
8969         if (ret)
8970                 goto out;
8971
8972         d_tmpfile(dentry, inode);
8973         mark_inode_dirty(inode);
8974
8975 out:
8976         btrfs_end_transaction(trans, root);
8977         if (ret)
8978                 iput(inode);
8979         btrfs_balance_delayed_items(root);
8980         btrfs_btree_balance_dirty(root);
8981
8982         return ret;
8983 }
8984
8985 static const struct inode_operations btrfs_dir_inode_operations = {
8986         .getattr        = btrfs_getattr,
8987         .lookup         = btrfs_lookup,
8988         .create         = btrfs_create,
8989         .unlink         = btrfs_unlink,
8990         .link           = btrfs_link,
8991         .mkdir          = btrfs_mkdir,
8992         .rmdir          = btrfs_rmdir,
8993         .rename         = btrfs_rename,
8994         .symlink        = btrfs_symlink,
8995         .setattr        = btrfs_setattr,
8996         .mknod          = btrfs_mknod,
8997         .setxattr       = btrfs_setxattr,
8998         .getxattr       = btrfs_getxattr,
8999         .listxattr      = btrfs_listxattr,
9000         .removexattr    = btrfs_removexattr,
9001         .permission     = btrfs_permission,
9002         .get_acl        = btrfs_get_acl,
9003         .set_acl        = btrfs_set_acl,
9004         .update_time    = btrfs_update_time,
9005         .tmpfile        = btrfs_tmpfile,
9006 };
9007 static const struct inode_operations btrfs_dir_ro_inode_operations = {
9008         .lookup         = btrfs_lookup,
9009         .permission     = btrfs_permission,
9010         .get_acl        = btrfs_get_acl,
9011         .set_acl        = btrfs_set_acl,
9012         .update_time    = btrfs_update_time,
9013 };
9014
9015 static const struct file_operations btrfs_dir_file_operations = {
9016         .llseek         = generic_file_llseek,
9017         .read           = generic_read_dir,
9018         .iterate        = btrfs_real_readdir,
9019         .unlocked_ioctl = btrfs_ioctl,
9020 #ifdef CONFIG_COMPAT
9021         .compat_ioctl   = btrfs_ioctl,
9022 #endif
9023         .release        = btrfs_release_file,
9024         .fsync          = btrfs_sync_file,
9025 };
9026
9027 static struct extent_io_ops btrfs_extent_io_ops = {
9028         .fill_delalloc = run_delalloc_range,
9029         .submit_bio_hook = btrfs_submit_bio_hook,
9030         .merge_bio_hook = btrfs_merge_bio_hook,
9031         .readpage_end_io_hook = btrfs_readpage_end_io_hook,
9032         .writepage_end_io_hook = btrfs_writepage_end_io_hook,
9033         .writepage_start_hook = btrfs_writepage_start_hook,
9034         .set_bit_hook = btrfs_set_bit_hook,
9035         .clear_bit_hook = btrfs_clear_bit_hook,
9036         .merge_extent_hook = btrfs_merge_extent_hook,
9037         .split_extent_hook = btrfs_split_extent_hook,
9038 };
9039
9040 /*
9041  * btrfs doesn't support the bmap operation because swapfiles
9042  * use bmap to make a mapping of extents in the file.  They assume
9043  * these extents won't change over the life of the file and they
9044  * use the bmap result to do IO directly to the drive.
9045  *
9046  * the btrfs bmap call would return logical addresses that aren't
9047  * suitable for IO and they also will change frequently as COW
9048  * operations happen.  So, swapfile + btrfs == corruption.
9049  *
9050  * For now we're avoiding this by dropping bmap.
9051  */
9052 static const struct address_space_operations btrfs_aops = {
9053         .readpage       = btrfs_readpage,
9054         .writepage      = btrfs_writepage,
9055         .writepages     = btrfs_writepages,
9056         .readpages      = btrfs_readpages,
9057         .direct_IO      = btrfs_direct_IO,
9058         .invalidatepage = btrfs_invalidatepage,
9059         .releasepage    = btrfs_releasepage,
9060         .set_page_dirty = btrfs_set_page_dirty,
9061         .error_remove_page = generic_error_remove_page,
9062 };
9063
9064 static const struct address_space_operations btrfs_symlink_aops = {
9065         .readpage       = btrfs_readpage,
9066         .writepage      = btrfs_writepage,
9067         .invalidatepage = btrfs_invalidatepage,
9068         .releasepage    = btrfs_releasepage,
9069 };
9070
9071 static const struct inode_operations btrfs_file_inode_operations = {
9072         .getattr        = btrfs_getattr,
9073         .setattr        = btrfs_setattr,
9074         .setxattr       = btrfs_setxattr,
9075         .getxattr       = btrfs_getxattr,
9076         .listxattr      = btrfs_listxattr,
9077         .removexattr    = btrfs_removexattr,
9078         .permission     = btrfs_permission,
9079         .fiemap         = btrfs_fiemap,
9080         .get_acl        = btrfs_get_acl,
9081         .set_acl        = btrfs_set_acl,
9082         .update_time    = btrfs_update_time,
9083 };
9084 static const struct inode_operations btrfs_special_inode_operations = {
9085         .getattr        = btrfs_getattr,
9086         .setattr        = btrfs_setattr,
9087         .permission     = btrfs_permission,
9088         .setxattr       = btrfs_setxattr,
9089         .getxattr       = btrfs_getxattr,
9090         .listxattr      = btrfs_listxattr,
9091         .removexattr    = btrfs_removexattr,
9092         .get_acl        = btrfs_get_acl,
9093         .set_acl        = btrfs_set_acl,
9094         .update_time    = btrfs_update_time,
9095 };
9096 static const struct inode_operations btrfs_symlink_inode_operations = {
9097         .readlink       = generic_readlink,
9098         .follow_link    = page_follow_link_light,
9099         .put_link       = page_put_link,
9100         .getattr        = btrfs_getattr,
9101         .setattr        = btrfs_setattr,
9102         .permission     = btrfs_permission,
9103         .setxattr       = btrfs_setxattr,
9104         .getxattr       = btrfs_getxattr,
9105         .listxattr      = btrfs_listxattr,
9106         .removexattr    = btrfs_removexattr,
9107         .update_time    = btrfs_update_time,
9108 };
9109
9110 const struct dentry_operations btrfs_dentry_operations = {
9111         .d_delete       = btrfs_dentry_delete,
9112         .d_release      = btrfs_dentry_release,
9113 };