fs/ext4/file.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  *  linux/fs/ext4/file.c
   4  *
   5  * Copyright (C) 1992, 1993, 1994, 1995
   6  * Remy Card ([email protected])
   7  * Laboratoire MASI - Institut Blaise Pascal
   8  * Universite Pierre et Marie Curie (Paris VI)
   9  *
  10  *  from
  11  *
  12  *  linux/fs/minix/file.c
  13  *
  14  *  Copyright (C) 1991, 1992  Linus Torvalds
  15  *
  16  *  ext4 fs regular file handling primitives
  17  *
  18  *  64-bit file support on 64-bit platforms by Jakub Jelinek
  19  *      ([email protected])
  20  */
  21
  22 #include <linux/time.h>
  23 #include <linux/fs.h>
  24 #include <linux/mount.h>
  25 #include <linux/path.h>
  26 #include <linux/dax.h>
  27 #include <linux/quotaops.h>
  28 #include <linux/pagevec.h>
  29 #include <linux/uio.h>
  30 #include "ext4.h"
  31 #include "ext4_jbd2.h"
  32 #include "xattr.h"
  33 #include "acl.h"
  34
  35 #ifdef CONFIG_FS_DAX
  36 static ssize_t ext4_dax_read_iter(struct kiocb *iocb, struct iov_iter *to)
  37 {
  38         struct inode *inode = file_inode(iocb->ki_filp);
  39         ssize_t ret;
  40
  41         if (!inode_trylock_shared(inode)) {
  42                 if (iocb->ki_flags & IOCB_NOWAIT)
  43                         return -EAGAIN;
  44                 inode_lock_shared(inode);
  45         }
  46         /*
  47          * Recheck under inode lock - at this point we are sure it cannot
  48          * change anymore
  49          */
  50         if (!IS_DAX(inode)) {
  51                 inode_unlock_shared(inode);
  52                 /* Fallback to buffered IO in case we cannot support DAX */
  53                 return generic_file_read_iter(iocb, to);
  54         }
  55         ret = dax_iomap_rw(iocb, to, &ext4_iomap_ops);
  56         inode_unlock_shared(inode);
  57
  58         file_accessed(iocb->ki_filp);
  59         return ret;
  60 }
  61 #endif
  62
  63 static ssize_t ext4_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
  64 {
  65         if (unlikely(ext4_forced_shutdown(EXT4_SB(file_inode(iocb->ki_filp)->i_sb))))
  66                 return -EIO;
  67
  68         if (!iov_iter_count(to))
  69                 return 0; /* skip atime */
  70
  71 #ifdef CONFIG_FS_DAX
  72         if (IS_DAX(file_inode(iocb->ki_filp)))
  73                 return ext4_dax_read_iter(iocb, to);
  74 #endif
  75         return generic_file_read_iter(iocb, to);
  76 }
  77
  78 /*
  79  * Called when an inode is released. Note that this is different
  80  * from ext4_file_open: open gets called at every open, but release
  81  * gets called only when /all/ the files are closed.
  82  */
  83 static int ext4_release_file(struct inode *inode, struct file *filp)
  84 {
  85         if (ext4_test_inode_state(inode, EXT4_STATE_DA_ALLOC_CLOSE)) {
  86                 ext4_alloc_da_blocks(inode);
  87                 ext4_clear_inode_state(inode, EXT4_STATE_DA_ALLOC_CLOSE);
  88         }
  89         /* if we are the last writer on the inode, drop the block reservation */
  90         if ((filp->f_mode & FMODE_WRITE) &&
  91                         (atomic_read(&inode->i_writecount) == 1) &&
  92                         !EXT4_I(inode)->i_reserved_data_blocks)
  93         {
  94                 down_write(&EXT4_I(inode)->i_data_sem);
  95                 ext4_discard_preallocations(inode);
  96                 up_write(&EXT4_I(inode)->i_data_sem);
  97         }
  98         if (is_dx(inode) && filp->private_data)
  99                 ext4_htree_free_dir_info(filp->private_data);
 100
 101         return 0;
 102 }
 103
 104 static void ext4_unwritten_wait(struct inode *inode)
 105 {
 106         wait_queue_head_t *wq = ext4_ioend_wq(inode);
 107
 108         wait_event(*wq, (atomic_read(&EXT4_I(inode)->i_unwritten) == 0));
 109 }
 110
 111 /*
 112  * This tests whether the IO in question is block-aligned or not.
 113  * Ext4 utilizes unwritten extents when hole-filling during direct IO, and they
 114  * are converted to written only after the IO is complete.  Until they are
 115  * mapped, these blocks appear as holes, so dio_zero_block() will assume that
 116  * it needs to zero out portions of the start and/or end block.  If 2 AIO
 117  * threads are at work on the same unwritten block, they must be synchronized
 118  * or one thread will zero the other's data, causing corruption.
 119  */
 120 static int
 121 ext4_unaligned_aio(struct inode *inode, struct iov_iter *from, loff_t pos)
 122 {
 123         struct super_block *sb = inode->i_sb;
 124         int blockmask = sb->s_blocksize - 1;
 125
 126         if (pos >= i_size_read(inode))
 127                 return 0;
 128
 129         if ((pos | iov_iter_alignment(from)) & blockmask)
 130                 return 1;
 131
 132         return 0;
 133 }
 134
 135 /* Is IO overwriting allocated and initialized blocks? */
 136 static bool ext4_overwrite_io(struct inode *inode, loff_t pos, loff_t len)
 137 {
 138         struct ext4_map_blocks map;
 139         unsigned int blkbits = inode->i_blkbits;
 140         int err, blklen;
 141
 142         if (pos + len > i_size_read(inode))
 143                 return false;
 144
 145         map.m_lblk = pos >> blkbits;
 146         map.m_len = EXT4_MAX_BLOCKS(len, pos, blkbits);
 147         blklen = map.m_len;
 148
 149         err = ext4_map_blocks(NULL, inode, &map, 0);
 150         /*
 151          * 'err==len' means that all of the blocks have been preallocated,
 152          * regardless of whether they have been initialized or not. To exclude
 153          * unwritten extents, we need to check m_flags.
 154          */
 155         return err == blklen && (map.m_flags & EXT4_MAP_MAPPED);
 156 }
 157
 158 static ssize_t ext4_write_checks(struct kiocb *iocb, struct iov_iter *from)
 159 {
 160         struct inode *inode = file_inode(iocb->ki_filp);
 161         ssize_t ret;
 162
 163         ret = generic_write_checks(iocb, from);
 164         if (ret <= 0)
 165                 return ret;
 166         /*
 167          * If we have encountered a bitmap-format file, the size limit
 168          * is smaller than s_maxbytes, which is for extent-mapped files.
 169          */
 170         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
 171                 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
 172
 173                 if (iocb->ki_pos >= sbi->s_bitmap_maxbytes)
 174                         return -EFBIG;
 175                 iov_iter_truncate(from, sbi->s_bitmap_maxbytes - iocb->ki_pos);
 176         }
 177         return iov_iter_count(from);
 178 }
 179
 180 #ifdef CONFIG_FS_DAX
 181 static ssize_t
 182 ext4_dax_write_iter(struct kiocb *iocb, struct iov_iter *from)
 183 {
 184         struct inode *inode = file_inode(iocb->ki_filp);
 185         ssize_t ret;
 186
 187         if (!inode_trylock(inode)) {
 188                 if (iocb->ki_flags & IOCB_NOWAIT)
 189                         return -EAGAIN;
 190                 inode_lock(inode);
 191         }
 192         ret = ext4_write_checks(iocb, from);
 193         if (ret <= 0)
 194                 goto out;
 195         ret = file_remove_privs(iocb->ki_filp);
 196         if (ret)
 197                 goto out;
 198         ret = file_update_time(iocb->ki_filp);
 199         if (ret)
 200                 goto out;
 201
 202         ret = dax_iomap_rw(iocb, from, &ext4_iomap_ops);
 203 out:
 204         inode_unlock(inode);
 205         if (ret > 0)
 206                 ret = generic_write_sync(iocb, ret);
 207         return ret;
 208 }
 209 #endif
 210
 211 static ssize_t
 212 ext4_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
 213 {
 214         struct inode *inode = file_inode(iocb->ki_filp);
 215         int o_direct = iocb->ki_flags & IOCB_DIRECT;
 216         int unaligned_aio = 0;
 217         int overwrite = 0;
 218         ssize_t ret;
 219
 220         if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
 221                 return -EIO;
 222
 223 #ifdef CONFIG_FS_DAX
 224         if (IS_DAX(inode))
 225                 return ext4_dax_write_iter(iocb, from);
 226 #endif
 227         if (!o_direct && (iocb->ki_flags & IOCB_NOWAIT))
 228                 return -EOPNOTSUPP;
 229
 230         if (!inode_trylock(inode)) {
 231                 if (iocb->ki_flags & IOCB_NOWAIT)
 232                         return -EAGAIN;
 233                 inode_lock(inode);
 234         }
 235
 236         ret = ext4_write_checks(iocb, from);
 237         if (ret <= 0)
 238                 goto out;
 239
 240         /*
 241          * Unaligned direct AIO must be serialized among each other as zeroing
 242          * of partial blocks of two competing unaligned AIOs can result in data
 243          * corruption.
 244          */
 245         if (o_direct && ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS) &&
 246             !is_sync_kiocb(iocb) &&
 247             ext4_unaligned_aio(inode, from, iocb->ki_pos)) {
 248                 unaligned_aio = 1;
 249                 ext4_unwritten_wait(inode);
 250         }
 251
 252         iocb->private = &overwrite;
 253         /* Check whether we do a DIO overwrite or not */
 254         if (o_direct && !unaligned_aio) {
 255                 if (ext4_overwrite_io(inode, iocb->ki_pos, iov_iter_count(from))) {
 256                         if (ext4_should_dioread_nolock(inode))
 257                                 overwrite = 1;
 258                 } else if (iocb->ki_flags & IOCB_NOWAIT) {
 259                         ret = -EAGAIN;
 260                         goto out;
 261                 }
 262         }
 263
 264         ret = __generic_file_write_iter(iocb, from);
 265         inode_unlock(inode);
 266
 267         if (ret > 0)
 268                 ret = generic_write_sync(iocb, ret);
 269
 270         return ret;
 271
 272 out:
 273         inode_unlock(inode);
 274         return ret;
 275 }
 276
 277 #ifdef CONFIG_FS_DAX
 278 static int ext4_dax_huge_fault(struct vm_fault *vmf,
 279                 enum page_entry_size pe_size)
 280 {
 281         int result;
 282         handle_t *handle = NULL;
 283         struct inode *inode = file_inode(vmf->vma->vm_file);
 284         struct super_block *sb = inode->i_sb;
 285
 286         /*
 287          * We have to distinguish real writes from writes which will result in a
 288          * COW page; COW writes should *not* poke the journal (the file will not
 289          * be changed). Doing so would cause unintended failures when mounted
 290          * read-only.
 291          *
 292          * We check for VM_SHARED rather than vmf->cow_page since the latter is
 293          * unset for pe_size != PE_SIZE_PTE (i.e. only in do_cow_fault); for
 294          * other sizes, dax_iomap_fault will handle splitting / fallback so that
 295          * we eventually come back with a COW page.
 296          */
 297         bool write = (vmf->flags & FAULT_FLAG_WRITE) &&
 298                 (vmf->vma->vm_flags & VM_SHARED);
 299
 300         if (write) {
 301                 sb_start_pagefault(sb);
 302                 file_update_time(vmf->vma->vm_file);
 303                 down_read(&EXT4_I(inode)->i_mmap_sem);
 304                 handle = ext4_journal_start_sb(sb, EXT4_HT_WRITE_PAGE,
 305                                                EXT4_DATA_TRANS_BLOCKS(sb));
 306         } else {
 307                 down_read(&EXT4_I(inode)->i_mmap_sem);
 308         }
 309         if (!IS_ERR(handle))
 310                 result = dax_iomap_fault(vmf, pe_size, &ext4_iomap_ops);
 311         else
 312                 result = VM_FAULT_SIGBUS;
 313         if (write) {
 314                 if (!IS_ERR(handle))
 315                         ext4_journal_stop(handle);
 316                 up_read(&EXT4_I(inode)->i_mmap_sem);
 317                 sb_end_pagefault(sb);
 318         } else {
 319                 up_read(&EXT4_I(inode)->i_mmap_sem);
 320         }
 321
 322         return result;
 323 }
 324
 325 static int ext4_dax_fault(struct vm_fault *vmf)
 326 {
 327         return ext4_dax_huge_fault(vmf, PE_SIZE_PTE);
 328 }
 329
 330 static const struct vm_operations_struct ext4_dax_vm_ops = {
 331         .fault          = ext4_dax_fault,
 332         .huge_fault     = ext4_dax_huge_fault,
 333         .page_mkwrite   = ext4_dax_fault,
 334         .pfn_mkwrite    = ext4_dax_fault,
 335 };
 336 #else
 337 #define ext4_dax_vm_ops ext4_file_vm_ops
 338 #endif
 339
 340 static const struct vm_operations_struct ext4_file_vm_ops = {
 341         .fault          = ext4_filemap_fault,
 342         .map_pages      = filemap_map_pages,
 343         .page_mkwrite   = ext4_page_mkwrite,
 344 };
 345
 346 static int ext4_file_mmap(struct file *file, struct vm_area_struct *vma)
 347 {
 348         struct inode *inode = file->f_mapping->host;
 349
 350         if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
 351                 return -EIO;
 352
 353         file_accessed(file);
 354         if (IS_DAX(file_inode(file))) {
 355                 vma->vm_ops = &ext4_dax_vm_ops;
 356                 vma->vm_flags |= VM_MIXEDMAP | VM_HUGEPAGE;
 357         } else {
 358                 vma->vm_ops = &ext4_file_vm_ops;
 359         }
 360         return 0;
 361 }
 362
 363 static int ext4_file_open(struct inode * inode, struct file * filp)
 364 {
 365         struct super_block *sb = inode->i_sb;
 366         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
 367         struct vfsmount *mnt = filp->f_path.mnt;
 368         struct dentry *dir;
 369         struct path path;
 370         char buf[64], *cp;
 371         int ret;
 372
 373         if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
 374                 return -EIO;
 375
 376         if (unlikely(!(sbi->s_mount_flags & EXT4_MF_MNTDIR_SAMPLED) &&
 377                      !sb_rdonly(sb))) {
 378                 sbi->s_mount_flags |= EXT4_MF_MNTDIR_SAMPLED;
 379                 /*
 380                  * Sample where the filesystem has been mounted and
 381                  * store it in the superblock for sysadmin convenience
 382                  * when trying to sort through large numbers of block
 383                  * devices or filesystem images.
 384                  */
 385                 memset(buf, 0, sizeof(buf));
 386                 path.mnt = mnt;
 387                 path.dentry = mnt->mnt_root;
 388                 cp = d_path(&path, buf, sizeof(buf));
 389                 if (!IS_ERR(cp)) {
 390                         handle_t *handle;
 391                         int err;
 392
 393                         handle = ext4_journal_start_sb(sb, EXT4_HT_MISC, 1);
 394                         if (IS_ERR(handle))
 395                                 return PTR_ERR(handle);
 396                         BUFFER_TRACE(sbi->s_sbh, "get_write_access");
 397                         err = ext4_journal_get_write_access(handle, sbi->s_sbh);
 398                         if (err) {
 399                                 ext4_journal_stop(handle);
 400                                 return err;
 401                         }
 402                         strlcpy(sbi->s_es->s_last_mounted, cp,
 403                                 sizeof(sbi->s_es->s_last_mounted));
 404                         ext4_handle_dirty_super(handle, sb);
 405                         ext4_journal_stop(handle);
 406                 }
 407         }
 408         if (ext4_encrypted_inode(inode)) {
 409                 ret = fscrypt_get_encryption_info(inode);
 410                 if (ret)
 411                         return -EACCES;
 412                 if (!fscrypt_has_encryption_key(inode))
 413                         return -ENOKEY;
 414         }
 415
 416         dir = dget_parent(file_dentry(filp));
 417         if (ext4_encrypted_inode(d_inode(dir)) &&
 418                         !fscrypt_has_permitted_context(d_inode(dir), inode)) {
 419                 ext4_warning(inode->i_sb,
 420                              "Inconsistent encryption contexts: %lu/%lu",
 421                              (unsigned long) d_inode(dir)->i_ino,
 422                              (unsigned long) inode->i_ino);
 423                 dput(dir);
 424                 return -EPERM;
 425         }
 426         dput(dir);
 427         /*
 428          * Set up the jbd2_inode if we are opening the inode for
 429          * writing and the journal is present
 430          */
 431         if (filp->f_mode & FMODE_WRITE) {
 432                 ret = ext4_inode_attach_jinode(inode);
 433                 if (ret < 0)
 434                         return ret;
 435         }
 436
 437         filp->f_mode |= FMODE_NOWAIT;
 438         return dquot_file_open(inode, filp);
 439 }
 440
 441 /*
 442  * Here we use ext4_map_blocks() to get a block mapping for a extent-based
 443  * file rather than ext4_ext_walk_space() because we can introduce
 444  * SEEK_DATA/SEEK_HOLE for block-mapped and extent-mapped file at the same
 445  * function.  When extent status tree has been fully implemented, it will
 446  * track all extent status for a file and we can directly use it to
 447  * retrieve the offset for SEEK_DATA/SEEK_HOLE.
 448  */
 449
 450 /*
 451  * When we retrieve the offset for SEEK_DATA/SEEK_HOLE, we would need to
 452  * lookup page cache to check whether or not there has some data between
 453  * [startoff, endoff] because, if this range contains an unwritten extent,
 454  * we determine this extent as a data or a hole according to whether the
 455  * page cache has data or not.
 456  */
 457 static int ext4_find_unwritten_pgoff(struct inode *inode,
 458                                      int whence,
 459                                      ext4_lblk_t end_blk,
 460                                      loff_t *offset)
 461 {
 462         struct pagevec pvec;
 463         unsigned int blkbits;
 464         pgoff_t index;
 465         pgoff_t end;
 466         loff_t endoff;
 467         loff_t startoff;
 468         loff_t lastoff;
 469         int found = 0;
 470
 471         blkbits = inode->i_sb->s_blocksize_bits;
 472         startoff = *offset;
 473         lastoff = startoff;
 474         endoff = (loff_t)end_blk << blkbits;
 475
 476         index = startoff >> PAGE_SHIFT;
 477         end = (endoff - 1) >> PAGE_SHIFT;
 478
 479         pagevec_init(&pvec, 0);
 480         do {
 481                 int i;
 482                 unsigned long nr_pages;
 483
 484                 nr_pages = pagevec_lookup_range(&pvec, inode->i_mapping,
 485                                         &index, end);
 486                 if (nr_pages == 0)
 487                         break;
 488
 489                 for (i = 0; i < nr_pages; i++) {
 490                         struct page *page = pvec.pages[i];
 491                         struct buffer_head *bh, *head;
 492
 493                         /*
 494                          * If current offset is smaller than the page offset,
 495                          * there is a hole at this offset.
 496                          */
 497                         if (whence == SEEK_HOLE && lastoff < endoff &&
 498                             lastoff < page_offset(pvec.pages[i])) {
 499                                 found = 1;
 500                                 *offset = lastoff;
 501                                 goto out;
 502                         }
 503
 504                         lock_page(page);
 505
 506                         if (unlikely(page->mapping != inode->i_mapping)) {
 507                                 unlock_page(page);
 508                                 continue;
 509                         }
 510
 511                         if (!page_has_buffers(page)) {
 512                                 unlock_page(page);
 513                                 continue;
 514                         }
 515
 516                         if (page_has_buffers(page)) {
 517                                 lastoff = page_offset(page);
 518                                 bh = head = page_buffers(page);
 519                                 do {
 520                                         if (lastoff + bh->b_size <= startoff)
 521                                                 goto next;
 522                                         if (buffer_uptodate(bh) ||
 523                                             buffer_unwritten(bh)) {
 524                                                 if (whence == SEEK_DATA)
 525                                                         found = 1;
 526                                         } else {
 527                                                 if (whence == SEEK_HOLE)
 528                                                         found = 1;
 529                                         }
 530                                         if (found) {
 531                                                 *offset = max_t(loff_t,
 532                                                         startoff, lastoff);
 533                                                 unlock_page(page);
 534                                                 goto out;
 535                                         }
 536 next:
 537                                         lastoff += bh->b_size;
 538                                         bh = bh->b_this_page;
 539                                 } while (bh != head);
 540                         }
 541
 542                         lastoff = page_offset(page) + PAGE_SIZE;
 543                         unlock_page(page);
 544                 }
 545
 546                 pagevec_release(&pvec);
 547         } while (index <= end);
 548
 549         /* There are no pages upto endoff - that would be a hole in there. */
 550         if (whence == SEEK_HOLE && lastoff < endoff) {
 551                 found = 1;
 552                 *offset = lastoff;
 553         }
 554 out:
 555         pagevec_release(&pvec);
 556         return found;
 557 }
 558
 559 /*
 560  * ext4_seek_data() retrieves the offset for SEEK_DATA.
 561  */
 562 static loff_t ext4_seek_data(struct file *file, loff_t offset, loff_t maxsize)
 563 {
 564         struct inode *inode = file->f_mapping->host;
 565         struct extent_status es;
 566         ext4_lblk_t start, last, end;
 567         loff_t dataoff, isize;
 568         int blkbits;
 569         int ret;
 570
 571         inode_lock(inode);
 572
 573         isize = i_size_read(inode);
 574         if (offset < 0 || offset >= isize) {
 575                 inode_unlock(inode);
 576                 return -ENXIO;
 577         }
 578
 579         blkbits = inode->i_sb->s_blocksize_bits;
 580         start = offset >> blkbits;
 581         last = start;
 582         end = isize >> blkbits;
 583         dataoff = offset;
 584
 585         do {
 586                 ret = ext4_get_next_extent(inode, last, end - last + 1, &es);
 587                 if (ret <= 0) {
 588                         /* No extent found -> no data */
 589                         if (ret == 0)
 590                                 ret = -ENXIO;
 591                         inode_unlock(inode);
 592                         return ret;
 593                 }
 594
 595                 last = es.es_lblk;
 596                 if (last != start)
 597                         dataoff = (loff_t)last << blkbits;
 598                 if (!ext4_es_is_unwritten(&es))
 599                         break;
 600
 601                 /*
 602                  * If there is a unwritten extent at this offset,
 603                  * it will be as a data or a hole according to page
 604                  * cache that has data or not.
 605                  */
 606                 if (ext4_find_unwritten_pgoff(inode, SEEK_DATA,
 607                                               es.es_lblk + es.es_len, &dataoff))
 608                         break;
 609                 last += es.es_len;
 610                 dataoff = (loff_t)last << blkbits;
 611                 cond_resched();
 612         } while (last <= end);
 613
 614         inode_unlock(inode);
 615
 616         if (dataoff > isize)
 617                 return -ENXIO;
 618
 619         return vfs_setpos(file, dataoff, maxsize);
 620 }
 621
 622 /*
 623  * ext4_seek_hole() retrieves the offset for SEEK_HOLE.
 624  */
 625 static loff_t ext4_seek_hole(struct file *file, loff_t offset, loff_t maxsize)
 626 {
 627         struct inode *inode = file->f_mapping->host;
 628         struct extent_status es;
 629         ext4_lblk_t start, last, end;
 630         loff_t holeoff, isize;
 631         int blkbits;
 632         int ret;
 633
 634         inode_lock(inode);
 635
 636         isize = i_size_read(inode);
 637         if (offset < 0 || offset >= isize) {
 638                 inode_unlock(inode);
 639                 return -ENXIO;
 640         }
 641
 642         blkbits = inode->i_sb->s_blocksize_bits;
 643         start = offset >> blkbits;
 644         last = start;
 645         end = isize >> blkbits;
 646         holeoff = offset;
 647
 648         do {
 649                 ret = ext4_get_next_extent(inode, last, end - last + 1, &es);
 650                 if (ret < 0) {
 651                         inode_unlock(inode);
 652                         return ret;
 653                 }
 654                 /* Found a hole? */
 655                 if (ret == 0 || es.es_lblk > last) {
 656                         if (last != start)
 657                                 holeoff = (loff_t)last << blkbits;
 658                         break;
 659                 }
 660                 /*
 661                  * If there is a unwritten extent at this offset,
 662                  * it will be as a data or a hole according to page
 663                  * cache that has data or not.
 664                  */
 665                 if (ext4_es_is_unwritten(&es) &&
 666                     ext4_find_unwritten_pgoff(inode, SEEK_HOLE,
 667                                               last + es.es_len, &holeoff))
 668                         break;
 669
 670                 last += es.es_len;
 671                 holeoff = (loff_t)last << blkbits;
 672                 cond_resched();
 673         } while (last <= end);
 674
 675         inode_unlock(inode);
 676
 677         if (holeoff > isize)
 678                 holeoff = isize;
 679
 680         return vfs_setpos(file, holeoff, maxsize);
 681 }
 682
 683 /*
 684  * ext4_llseek() handles both block-mapped and extent-mapped maxbytes values
 685  * by calling generic_file_llseek_size() with the appropriate maxbytes
 686  * value for each.
 687  */
 688 loff_t ext4_llseek(struct file *file, loff_t offset, int whence)
 689 {
 690         struct inode *inode = file->f_mapping->host;
 691         loff_t maxbytes;
 692
 693         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
 694                 maxbytes = EXT4_SB(inode->i_sb)->s_bitmap_maxbytes;
 695         else
 696                 maxbytes = inode->i_sb->s_maxbytes;
 697
 698         switch (whence) {
 699         case SEEK_SET:
 700         case SEEK_CUR:
 701         case SEEK_END:
 702                 return generic_file_llseek_size(file, offset, whence,
 703                                                 maxbytes, i_size_read(inode));
 704         case SEEK_DATA:
 705                 return ext4_seek_data(file, offset, maxbytes);
 706         case SEEK_HOLE:
 707                 return ext4_seek_hole(file, offset, maxbytes);
 708         }
 709
 710         return -EINVAL;
 711 }
 712
 713 const struct file_operations ext4_file_operations = {
 714         .llseek         = ext4_llseek,
 715         .read_iter      = ext4_file_read_iter,
 716         .write_iter     = ext4_file_write_iter,
 717         .unlocked_ioctl = ext4_ioctl,
 718 #ifdef CONFIG_COMPAT
 719         .compat_ioctl   = ext4_compat_ioctl,
 720 #endif
 721         .mmap           = ext4_file_mmap,
 722         .open           = ext4_file_open,
 723         .release        = ext4_release_file,
 724         .fsync          = ext4_sync_file,
 725         .get_unmapped_area = thp_get_unmapped_area,
 726         .splice_read    = generic_file_splice_read,
 727         .splice_write   = iter_file_splice_write,
 728         .fallocate      = ext4_fallocate,
 729 };
 730
 731 const struct inode_operations ext4_file_inode_operations = {
 732         .setattr        = ext4_setattr,
 733         .getattr        = ext4_file_getattr,
 734         .listxattr      = ext4_listxattr,
 735         .get_acl        = ext4_get_acl,
 736         .set_acl        = ext4_set_acl,
 737         .fiemap         = ext4_fiemap,
 738 };
 739