fs/nilfs2/super.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * NILFS module and super block management.
   4  *
   5  * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
   6  *
   7  * Written by Ryusuke Konishi.
   8  */
   9 /*
  10  *  linux/fs/ext2/super.c
  11  *
  12  * Copyright (C) 1992, 1993, 1994, 1995
  13  * Remy Card ([email protected])
  14  * Laboratoire MASI - Institut Blaise Pascal
  15  * Universite Pierre et Marie Curie (Paris VI)
  16  *
  17  *  from
  18  *
  19  *  linux/fs/minix/inode.c
  20  *
  21  *  Copyright (C) 1991, 1992  Linus Torvalds
  22  *
  23  *  Big-endian to little-endian byte-swapping/bitmaps by
  24  *        David S. Miller ([email protected]), 1995
  25  */
  26
  27 #include <linux/module.h>
  28 #include <linux/string.h>
  29 #include <linux/slab.h>
  30 #include <linux/init.h>
  31 #include <linux/blkdev.h>
  32 #include <linux/crc32.h>
  33 #include <linux/vfs.h>
  34 #include <linux/writeback.h>
  35 #include <linux/seq_file.h>
  36 #include <linux/mount.h>
  37 #include <linux/fs_context.h>
  38 #include <linux/fs_parser.h>
  39 #include "nilfs.h"
  40 #include "export.h"
  41 #include "mdt.h"
  42 #include "alloc.h"
  43 #include "btree.h"
  44 #include "btnode.h"
  45 #include "page.h"
  46 #include "cpfile.h"
  47 #include "sufile.h" /* nilfs_sufile_resize(), nilfs_sufile_set_alloc_range() */
  48 #include "ifile.h"
  49 #include "dat.h"
  50 #include "segment.h"
  51 #include "segbuf.h"
  52
  53 MODULE_AUTHOR("NTT Corp.");
  54 MODULE_DESCRIPTION("A New Implementation of the Log-structured Filesystem "
  55                    "(NILFS)");
  56 MODULE_LICENSE("GPL");
  57
  58 static struct kmem_cache *nilfs_inode_cachep;
  59 struct kmem_cache *nilfs_transaction_cachep;
  60 struct kmem_cache *nilfs_segbuf_cachep;
  61 struct kmem_cache *nilfs_btree_path_cache;
  62
  63 static int nilfs_setup_super(struct super_block *sb, int is_mount);
  64
  65 void __nilfs_msg(struct super_block *sb, const char *fmt, ...)
  66 {
  67         struct va_format vaf;
  68         va_list args;
  69         int level;
  70
  71         va_start(args, fmt);
  72
  73         level = printk_get_level(fmt);
  74         vaf.fmt = printk_skip_level(fmt);
  75         vaf.va = &args;
  76
  77         if (sb)
  78                 printk("%c%cNILFS (%s): %pV\n",
  79                        KERN_SOH_ASCII, level, sb->s_id, &vaf);
  80         else
  81                 printk("%c%cNILFS: %pV\n",
  82                        KERN_SOH_ASCII, level, &vaf);
  83
  84         va_end(args);
  85 }
  86
  87 static void nilfs_set_error(struct super_block *sb)
  88 {
  89         struct the_nilfs *nilfs = sb->s_fs_info;
  90         struct nilfs_super_block **sbp;
  91
  92         down_write(&nilfs->ns_sem);
  93         if (!(nilfs->ns_mount_state & NILFS_ERROR_FS)) {
  94                 nilfs->ns_mount_state |= NILFS_ERROR_FS;
  95                 sbp = nilfs_prepare_super(sb, 0);
  96                 if (likely(sbp)) {
  97                         sbp[0]->s_state |= cpu_to_le16(NILFS_ERROR_FS);
  98                         if (sbp[1])
  99                                 sbp[1]->s_state |= cpu_to_le16(NILFS_ERROR_FS);
 100                         nilfs_commit_super(sb, NILFS_SB_COMMIT_ALL);
 101                 }
 102         }
 103         up_write(&nilfs->ns_sem);
 104 }
 105
 106 /**
 107  * __nilfs_error() - report failure condition on a filesystem
 108  * @sb:       super block instance
 109  * @function: name of calling function
 110  * @fmt:      format string for message to be output
 111  * @...:      optional arguments to @fmt
 112  *
 113  * __nilfs_error() sets an ERROR_FS flag on the superblock as well as
 114  * reporting an error message.  This function should be called when
 115  * NILFS detects incoherences or defects of meta data on disk.
 116  *
 117  * This implements the body of nilfs_error() macro.  Normally,
 118  * nilfs_error() should be used.  As for sustainable errors such as a
 119  * single-shot I/O error, nilfs_err() should be used instead.
 120  *
 121  * Callers should not add a trailing newline since this will do it.
 122  */
 123 void __nilfs_error(struct super_block *sb, const char *function,
 124                    const char *fmt, ...)
 125 {
 126         struct the_nilfs *nilfs = sb->s_fs_info;
 127         struct va_format vaf;
 128         va_list args;
 129
 130         va_start(args, fmt);
 131
 132         vaf.fmt = fmt;
 133         vaf.va = &args;
 134
 135         printk(KERN_CRIT "NILFS error (device %s): %s: %pV\n",
 136                sb->s_id, function, &vaf);
 137
 138         va_end(args);
 139
 140         if (!sb_rdonly(sb)) {
 141                 nilfs_set_error(sb);
 142
 143                 if (nilfs_test_opt(nilfs, ERRORS_RO)) {
 144                         printk(KERN_CRIT "Remounting filesystem read-only\n");
 145                         sb->s_flags |= SB_RDONLY;
 146                 }
 147         }
 148
 149         if (nilfs_test_opt(nilfs, ERRORS_PANIC))
 150                 panic("NILFS (device %s): panic forced after error\n",
 151                       sb->s_id);
 152 }
 153
 154 struct inode *nilfs_alloc_inode(struct super_block *sb)
 155 {
 156         struct nilfs_inode_info *ii;
 157
 158         ii = alloc_inode_sb(sb, nilfs_inode_cachep, GFP_NOFS);
 159         if (!ii)
 160                 return NULL;
 161         ii->i_bh = NULL;
 162         ii->i_state = 0;
 163         ii->i_type = 0;
 164         ii->i_cno = 0;
 165         ii->i_assoc_inode = NULL;
 166         ii->i_bmap = &ii->i_bmap_data;
 167         return &ii->vfs_inode;
 168 }
 169
 170 static void nilfs_free_inode(struct inode *inode)
 171 {
 172         if (nilfs_is_metadata_file_inode(inode))
 173                 nilfs_mdt_destroy(inode);
 174
 175         kmem_cache_free(nilfs_inode_cachep, NILFS_I(inode));
 176 }
 177
 178 static int nilfs_sync_super(struct super_block *sb, int flag)
 179 {
 180         struct the_nilfs *nilfs = sb->s_fs_info;
 181         int err;
 182
 183  retry:
 184         set_buffer_dirty(nilfs->ns_sbh[0]);
 185         if (nilfs_test_opt(nilfs, BARRIER)) {
 186                 err = __sync_dirty_buffer(nilfs->ns_sbh[0],
 187                                           REQ_SYNC | REQ_PREFLUSH | REQ_FUA);
 188         } else {
 189                 err = sync_dirty_buffer(nilfs->ns_sbh[0]);
 190         }
 191
 192         if (unlikely(err)) {
 193                 nilfs_err(sb, "unable to write superblock: err=%d", err);
 194                 if (err == -EIO && nilfs->ns_sbh[1]) {
 195                         /*
 196                          * sbp[0] points to newer log than sbp[1],
 197                          * so copy sbp[0] to sbp[1] to take over sbp[0].
 198                          */
 199                         memcpy(nilfs->ns_sbp[1], nilfs->ns_sbp[0],
 200                                nilfs->ns_sbsize);
 201                         nilfs_fall_back_super_block(nilfs);
 202                         goto retry;
 203                 }
 204         } else {
 205                 struct nilfs_super_block *sbp = nilfs->ns_sbp[0];
 206
 207                 nilfs->ns_sbwcount++;
 208
 209                 /*
 210                  * The latest segment becomes trailable from the position
 211                  * written in superblock.
 212                  */
 213                 clear_nilfs_discontinued(nilfs);
 214
 215                 /* update GC protection for recent segments */
 216                 if (nilfs->ns_sbh[1]) {
 217                         if (flag == NILFS_SB_COMMIT_ALL) {
 218                                 set_buffer_dirty(nilfs->ns_sbh[1]);
 219                                 if (sync_dirty_buffer(nilfs->ns_sbh[1]) < 0)
 220                                         goto out;
 221                         }
 222                         if (le64_to_cpu(nilfs->ns_sbp[1]->s_last_cno) <
 223                             le64_to_cpu(nilfs->ns_sbp[0]->s_last_cno))
 224                                 sbp = nilfs->ns_sbp[1];
 225                 }
 226
 227                 spin_lock(&nilfs->ns_last_segment_lock);
 228                 nilfs->ns_prot_seq = le64_to_cpu(sbp->s_last_seq);
 229                 spin_unlock(&nilfs->ns_last_segment_lock);
 230         }
 231  out:
 232         return err;
 233 }
 234
 235 void nilfs_set_log_cursor(struct nilfs_super_block *sbp,
 236                           struct the_nilfs *nilfs)
 237 {
 238         sector_t nfreeblocks;
 239
 240         /* nilfs->ns_sem must be locked by the caller. */
 241         nilfs_count_free_blocks(nilfs, &nfreeblocks);
 242         sbp->s_free_blocks_count = cpu_to_le64(nfreeblocks);
 243
 244         spin_lock(&nilfs->ns_last_segment_lock);
 245         sbp->s_last_seq = cpu_to_le64(nilfs->ns_last_seq);
 246         sbp->s_last_pseg = cpu_to_le64(nilfs->ns_last_pseg);
 247         sbp->s_last_cno = cpu_to_le64(nilfs->ns_last_cno);
 248         spin_unlock(&nilfs->ns_last_segment_lock);
 249 }
 250
 251 struct nilfs_super_block **nilfs_prepare_super(struct super_block *sb,
 252                                                int flip)
 253 {
 254         struct the_nilfs *nilfs = sb->s_fs_info;
 255         struct nilfs_super_block **sbp = nilfs->ns_sbp;
 256
 257         /* nilfs->ns_sem must be locked by the caller. */
 258         if (sbp[0]->s_magic != cpu_to_le16(NILFS_SUPER_MAGIC)) {
 259                 if (sbp[1] &&
 260                     sbp[1]->s_magic == cpu_to_le16(NILFS_SUPER_MAGIC)) {
 261                         memcpy(sbp[0], sbp[1], nilfs->ns_sbsize);
 262                 } else {
 263                         nilfs_crit(sb, "superblock broke");
 264                         return NULL;
 265                 }
 266         } else if (sbp[1] &&
 267                    sbp[1]->s_magic != cpu_to_le16(NILFS_SUPER_MAGIC)) {
 268                 memcpy(sbp[1], sbp[0], nilfs->ns_sbsize);
 269         }
 270
 271         if (flip && sbp[1])
 272                 nilfs_swap_super_block(nilfs);
 273
 274         return sbp;
 275 }
 276
 277 int nilfs_commit_super(struct super_block *sb, int flag)
 278 {
 279         struct the_nilfs *nilfs = sb->s_fs_info;
 280         struct nilfs_super_block **sbp = nilfs->ns_sbp;
 281         time64_t t;
 282
 283         /* nilfs->ns_sem must be locked by the caller. */
 284         t = ktime_get_real_seconds();
 285         nilfs->ns_sbwtime = t;
 286         sbp[0]->s_wtime = cpu_to_le64(t);
 287         sbp[0]->s_sum = 0;
 288         sbp[0]->s_sum = cpu_to_le32(crc32_le(nilfs->ns_crc_seed,
 289                                              (unsigned char *)sbp[0],
 290                                              nilfs->ns_sbsize));
 291         if (flag == NILFS_SB_COMMIT_ALL && sbp[1]) {
 292                 sbp[1]->s_wtime = sbp[0]->s_wtime;
 293                 sbp[1]->s_sum = 0;
 294                 sbp[1]->s_sum = cpu_to_le32(crc32_le(nilfs->ns_crc_seed,
 295                                             (unsigned char *)sbp[1],
 296                                             nilfs->ns_sbsize));
 297         }
 298         clear_nilfs_sb_dirty(nilfs);
 299         nilfs->ns_flushed_device = 1;
 300         /* make sure store to ns_flushed_device cannot be reordered */
 301         smp_wmb();
 302         return nilfs_sync_super(sb, flag);
 303 }
 304
 305 /**
 306  * nilfs_cleanup_super() - write filesystem state for cleanup
 307  * @sb: super block instance to be unmounted or degraded to read-only
 308  *
 309  * This function restores state flags in the on-disk super block.
 310  * This will set "clean" flag (i.e. NILFS_VALID_FS) unless the
 311  * filesystem was not clean previously.
 312  */
 313 int nilfs_cleanup_super(struct super_block *sb)
 314 {
 315         struct the_nilfs *nilfs = sb->s_fs_info;
 316         struct nilfs_super_block **sbp;
 317         int flag = NILFS_SB_COMMIT;
 318         int ret = -EIO;
 319
 320         sbp = nilfs_prepare_super(sb, 0);
 321         if (sbp) {
 322                 sbp[0]->s_state = cpu_to_le16(nilfs->ns_mount_state);
 323                 nilfs_set_log_cursor(sbp[0], nilfs);
 324                 if (sbp[1] && sbp[0]->s_last_cno == sbp[1]->s_last_cno) {
 325                         /*
 326                          * make the "clean" flag also to the opposite
 327                          * super block if both super blocks point to
 328                          * the same checkpoint.
 329                          */
 330                         sbp[1]->s_state = sbp[0]->s_state;
 331                         flag = NILFS_SB_COMMIT_ALL;
 332                 }
 333                 ret = nilfs_commit_super(sb, flag);
 334         }
 335         return ret;
 336 }
 337
 338 /**
 339  * nilfs_move_2nd_super - relocate secondary super block
 340  * @sb: super block instance
 341  * @sb2off: new offset of the secondary super block (in bytes)
 342  */
 343 static int nilfs_move_2nd_super(struct super_block *sb, loff_t sb2off)
 344 {
 345         struct the_nilfs *nilfs = sb->s_fs_info;
 346         struct buffer_head *nsbh;
 347         struct nilfs_super_block *nsbp;
 348         sector_t blocknr, newblocknr;
 349         unsigned long offset;
 350         int sb2i;  /* array index of the secondary superblock */
 351         int ret = 0;
 352
 353         /* nilfs->ns_sem must be locked by the caller. */
 354         if (nilfs->ns_sbh[1] &&
 355             nilfs->ns_sbh[1]->b_blocknr > nilfs->ns_first_data_block) {
 356                 sb2i = 1;
 357                 blocknr = nilfs->ns_sbh[1]->b_blocknr;
 358         } else if (nilfs->ns_sbh[0]->b_blocknr > nilfs->ns_first_data_block) {
 359                 sb2i = 0;
 360                 blocknr = nilfs->ns_sbh[0]->b_blocknr;
 361         } else {
 362                 sb2i = -1;
 363                 blocknr = 0;
 364         }
 365         if (sb2i >= 0 && (u64)blocknr << nilfs->ns_blocksize_bits == sb2off)
 366                 goto out;  /* super block location is unchanged */
 367
 368         /* Get new super block buffer */
 369         newblocknr = sb2off >> nilfs->ns_blocksize_bits;
 370         offset = sb2off & (nilfs->ns_blocksize - 1);
 371         nsbh = sb_getblk(sb, newblocknr);
 372         if (!nsbh) {
 373                 nilfs_warn(sb,
 374                            "unable to move secondary superblock to block %llu",
 375                            (unsigned long long)newblocknr);
 376                 ret = -EIO;
 377                 goto out;
 378         }
 379         nsbp = (void *)nsbh->b_data + offset;
 380
 381         lock_buffer(nsbh);
 382         if (sb2i >= 0) {
 383                 /*
 384                  * The position of the second superblock only changes by 4KiB,
 385                  * which is larger than the maximum superblock data size
 386                  * (= 1KiB), so there is no need to use memmove() to allow
 387                  * overlap between source and destination.
 388                  */
 389                 memcpy(nsbp, nilfs->ns_sbp[sb2i], nilfs->ns_sbsize);
 390
 391                 /*
 392                  * Zero fill after copy to avoid overwriting in case of move
 393                  * within the same block.
 394                  */
 395                 memset(nsbh->b_data, 0, offset);
 396                 memset((void *)nsbp + nilfs->ns_sbsize, 0,
 397                        nsbh->b_size - offset - nilfs->ns_sbsize);
 398         } else {
 399                 memset(nsbh->b_data, 0, nsbh->b_size);
 400         }
 401         set_buffer_uptodate(nsbh);
 402         unlock_buffer(nsbh);
 403
 404         if (sb2i >= 0) {
 405                 brelse(nilfs->ns_sbh[sb2i]);
 406                 nilfs->ns_sbh[sb2i] = nsbh;
 407                 nilfs->ns_sbp[sb2i] = nsbp;
 408         } else if (nilfs->ns_sbh[0]->b_blocknr < nilfs->ns_first_data_block) {
 409                 /* secondary super block will be restored to index 1 */
 410                 nilfs->ns_sbh[1] = nsbh;
 411                 nilfs->ns_sbp[1] = nsbp;
 412         } else {
 413                 brelse(nsbh);
 414         }
 415 out:
 416         return ret;
 417 }
 418
 419 /**
 420  * nilfs_resize_fs - resize the filesystem
 421  * @sb: super block instance
 422  * @newsize: new size of the filesystem (in bytes)
 423  */
 424 int nilfs_resize_fs(struct super_block *sb, __u64 newsize)
 425 {
 426         struct the_nilfs *nilfs = sb->s_fs_info;
 427         struct nilfs_super_block **sbp;
 428         __u64 devsize, newnsegs;
 429         loff_t sb2off;
 430         int ret;
 431
 432         ret = -ERANGE;
 433         devsize = bdev_nr_bytes(sb->s_bdev);
 434         if (newsize > devsize)
 435                 goto out;
 436
 437         /*
 438          * Prevent underflow in second superblock position calculation.
 439          * The exact minimum size check is done in nilfs_sufile_resize().
 440          */
 441         if (newsize < 4096) {
 442                 ret = -ENOSPC;
 443                 goto out;
 444         }
 445
 446         /*
 447          * Write lock is required to protect some functions depending
 448          * on the number of segments, the number of reserved segments,
 449          * and so forth.
 450          */
 451         down_write(&nilfs->ns_segctor_sem);
 452
 453         sb2off = NILFS_SB2_OFFSET_BYTES(newsize);
 454         newnsegs = sb2off >> nilfs->ns_blocksize_bits;
 455         newnsegs = div64_ul(newnsegs, nilfs->ns_blocks_per_segment);
 456
 457         ret = nilfs_sufile_resize(nilfs->ns_sufile, newnsegs);
 458         up_write(&nilfs->ns_segctor_sem);
 459         if (ret < 0)
 460                 goto out;
 461
 462         ret = nilfs_construct_segment(sb);
 463         if (ret < 0)
 464                 goto out;
 465
 466         down_write(&nilfs->ns_sem);
 467         nilfs_move_2nd_super(sb, sb2off);
 468         ret = -EIO;
 469         sbp = nilfs_prepare_super(sb, 0);
 470         if (likely(sbp)) {
 471                 nilfs_set_log_cursor(sbp[0], nilfs);
 472                 /*
 473                  * Drop NILFS_RESIZE_FS flag for compatibility with
 474                  * mount-time resize which may be implemented in a
 475                  * future release.
 476                  */
 477                 sbp[0]->s_state = cpu_to_le16(le16_to_cpu(sbp[0]->s_state) &
 478                                               ~NILFS_RESIZE_FS);
 479                 sbp[0]->s_dev_size = cpu_to_le64(newsize);
 480                 sbp[0]->s_nsegments = cpu_to_le64(nilfs->ns_nsegments);
 481                 if (sbp[1])
 482                         memcpy(sbp[1], sbp[0], nilfs->ns_sbsize);
 483                 ret = nilfs_commit_super(sb, NILFS_SB_COMMIT_ALL);
 484         }
 485         up_write(&nilfs->ns_sem);
 486
 487         /*
 488          * Reset the range of allocatable segments last.  This order
 489          * is important in the case of expansion because the secondary
 490          * superblock must be protected from log write until migration
 491          * completes.
 492          */
 493         if (!ret)
 494                 nilfs_sufile_set_alloc_range(nilfs->ns_sufile, 0, newnsegs - 1);
 495 out:
 496         return ret;
 497 }
 498
 499 static void nilfs_put_super(struct super_block *sb)
 500 {
 501         struct the_nilfs *nilfs = sb->s_fs_info;
 502
 503         nilfs_detach_log_writer(sb);
 504
 505         if (!sb_rdonly(sb)) {
 506                 down_write(&nilfs->ns_sem);
 507                 nilfs_cleanup_super(sb);
 508                 up_write(&nilfs->ns_sem);
 509         }
 510
 511         nilfs_sysfs_delete_device_group(nilfs);
 512         iput(nilfs->ns_sufile);
 513         iput(nilfs->ns_cpfile);
 514         iput(nilfs->ns_dat);
 515
 516         destroy_nilfs(nilfs);
 517         sb->s_fs_info = NULL;
 518 }
 519
 520 static int nilfs_sync_fs(struct super_block *sb, int wait)
 521 {
 522         struct the_nilfs *nilfs = sb->s_fs_info;
 523         struct nilfs_super_block **sbp;
 524         int err = 0;
 525
 526         /* This function is called when super block should be written back */
 527         if (wait)
 528                 err = nilfs_construct_segment(sb);
 529
 530         down_write(&nilfs->ns_sem);
 531         if (nilfs_sb_dirty(nilfs)) {
 532                 sbp = nilfs_prepare_super(sb, nilfs_sb_will_flip(nilfs));
 533                 if (likely(sbp)) {
 534                         nilfs_set_log_cursor(sbp[0], nilfs);
 535                         nilfs_commit_super(sb, NILFS_SB_COMMIT);
 536                 }
 537         }
 538         up_write(&nilfs->ns_sem);
 539
 540         if (!err)
 541                 err = nilfs_flush_device(nilfs);
 542
 543         return err;
 544 }
 545
 546 int nilfs_attach_checkpoint(struct super_block *sb, __u64 cno, int curr_mnt,
 547                             struct nilfs_root **rootp)
 548 {
 549         struct the_nilfs *nilfs = sb->s_fs_info;
 550         struct nilfs_root *root;
 551         int err = -ENOMEM;
 552
 553         root = nilfs_find_or_create_root(
 554                 nilfs, curr_mnt ? NILFS_CPTREE_CURRENT_CNO : cno);
 555         if (!root)
 556                 return err;
 557
 558         if (root->ifile)
 559                 goto reuse; /* already attached checkpoint */
 560
 561         down_read(&nilfs->ns_segctor_sem);
 562         err = nilfs_ifile_read(sb, root, cno, nilfs->ns_inode_size);
 563         up_read(&nilfs->ns_segctor_sem);
 564         if (unlikely(err))
 565                 goto failed;
 566
 567  reuse:
 568         *rootp = root;
 569         return 0;
 570
 571  failed:
 572         if (err == -EINVAL)
 573                 nilfs_err(sb, "Invalid checkpoint (checkpoint number=%llu)",
 574                           (unsigned long long)cno);
 575         nilfs_put_root(root);
 576
 577         return err;
 578 }
 579
 580 static int nilfs_freeze(struct super_block *sb)
 581 {
 582         struct the_nilfs *nilfs = sb->s_fs_info;
 583         int err;
 584
 585         if (sb_rdonly(sb))
 586                 return 0;
 587
 588         /* Mark super block clean */
 589         down_write(&nilfs->ns_sem);
 590         err = nilfs_cleanup_super(sb);
 591         up_write(&nilfs->ns_sem);
 592         return err;
 593 }
 594
 595 static int nilfs_unfreeze(struct super_block *sb)
 596 {
 597         struct the_nilfs *nilfs = sb->s_fs_info;
 598
 599         if (sb_rdonly(sb))
 600                 return 0;
 601
 602         down_write(&nilfs->ns_sem);
 603         nilfs_setup_super(sb, false);
 604         up_write(&nilfs->ns_sem);
 605         return 0;
 606 }
 607
 608 static int nilfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 609 {
 610         struct super_block *sb = dentry->d_sb;
 611         struct nilfs_root *root = NILFS_I(d_inode(dentry))->i_root;
 612         struct the_nilfs *nilfs = root->nilfs;
 613         u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
 614         unsigned long long blocks;
 615         unsigned long overhead;
 616         unsigned long nrsvblocks;
 617         sector_t nfreeblocks;
 618         u64 nmaxinodes, nfreeinodes;
 619         int err;
 620
 621         /*
 622          * Compute all of the segment blocks
 623          *
 624          * The blocks before first segment and after last segment
 625          * are excluded.
 626          */
 627         blocks = nilfs->ns_blocks_per_segment * nilfs->ns_nsegments
 628                 - nilfs->ns_first_data_block;
 629         nrsvblocks = nilfs->ns_nrsvsegs * nilfs->ns_blocks_per_segment;
 630
 631         /*
 632          * Compute the overhead
 633          *
 634          * When distributing meta data blocks outside segment structure,
 635          * We must count them as the overhead.
 636          */
 637         overhead = 0;
 638
 639         err = nilfs_count_free_blocks(nilfs, &nfreeblocks);
 640         if (unlikely(err))
 641                 return err;
 642
 643         err = nilfs_ifile_count_free_inodes(root->ifile,
 644                                             &nmaxinodes, &nfreeinodes);
 645         if (unlikely(err)) {
 646                 nilfs_warn(sb, "failed to count free inodes: err=%d", err);
 647                 if (err == -ERANGE) {
 648                         /*
 649                          * If nilfs_palloc_count_max_entries() returns
 650                          * -ERANGE error code then we simply treat
 651                          * curent inodes count as maximum possible and
 652                          * zero as free inodes value.
 653                          */
 654                         nmaxinodes = atomic64_read(&root->inodes_count);
 655                         nfreeinodes = 0;
 656                         err = 0;
 657                 } else
 658                         return err;
 659         }
 660
 661         buf->f_type = NILFS_SUPER_MAGIC;
 662         buf->f_bsize = sb->s_blocksize;
 663         buf->f_blocks = blocks - overhead;
 664         buf->f_bfree = nfreeblocks;
 665         buf->f_bavail = (buf->f_bfree >= nrsvblocks) ?
 666                 (buf->f_bfree - nrsvblocks) : 0;
 667         buf->f_files = nmaxinodes;
 668         buf->f_ffree = nfreeinodes;
 669         buf->f_namelen = NILFS_NAME_LEN;
 670         buf->f_fsid = u64_to_fsid(id);
 671
 672         return 0;
 673 }
 674
 675 static int nilfs_show_options(struct seq_file *seq, struct dentry *dentry)
 676 {
 677         struct super_block *sb = dentry->d_sb;
 678         struct the_nilfs *nilfs = sb->s_fs_info;
 679         struct nilfs_root *root = NILFS_I(d_inode(dentry))->i_root;
 680
 681         if (!nilfs_test_opt(nilfs, BARRIER))
 682                 seq_puts(seq, ",nobarrier");
 683         if (root->cno != NILFS_CPTREE_CURRENT_CNO)
 684                 seq_printf(seq, ",cp=%llu", (unsigned long long)root->cno);
 685         if (nilfs_test_opt(nilfs, ERRORS_PANIC))
 686                 seq_puts(seq, ",errors=panic");
 687         if (nilfs_test_opt(nilfs, ERRORS_CONT))
 688                 seq_puts(seq, ",errors=continue");
 689         if (nilfs_test_opt(nilfs, STRICT_ORDER))
 690                 seq_puts(seq, ",order=strict");
 691         if (nilfs_test_opt(nilfs, NORECOVERY))
 692                 seq_puts(seq, ",norecovery");
 693         if (nilfs_test_opt(nilfs, DISCARD))
 694                 seq_puts(seq, ",discard");
 695
 696         return 0;
 697 }
 698
 699 static const struct super_operations nilfs_sops = {
 700         .alloc_inode    = nilfs_alloc_inode,
 701         .free_inode     = nilfs_free_inode,
 702         .dirty_inode    = nilfs_dirty_inode,
 703         .evict_inode    = nilfs_evict_inode,
 704         .put_super      = nilfs_put_super,
 705         .sync_fs        = nilfs_sync_fs,
 706         .freeze_fs      = nilfs_freeze,
 707         .unfreeze_fs    = nilfs_unfreeze,
 708         .statfs         = nilfs_statfs,
 709         .show_options = nilfs_show_options
 710 };
 711
 712 enum {
 713         Opt_err, Opt_barrier, Opt_snapshot, Opt_order, Opt_norecovery,
 714         Opt_discard,
 715 };
 716
 717 static const struct constant_table nilfs_param_err[] = {
 718         {"continue",    NILFS_MOUNT_ERRORS_CONT},
 719         {"panic",       NILFS_MOUNT_ERRORS_PANIC},
 720         {"remount-ro",  NILFS_MOUNT_ERRORS_RO},
 721         {}
 722 };
 723
 724 static const struct fs_parameter_spec nilfs_param_spec[] = {
 725         fsparam_enum    ("errors", Opt_err, nilfs_param_err),
 726         fsparam_flag_no ("barrier", Opt_barrier),
 727         fsparam_u64     ("cp", Opt_snapshot),
 728         fsparam_string  ("order", Opt_order),
 729         fsparam_flag    ("norecovery", Opt_norecovery),
 730         fsparam_flag_no ("discard", Opt_discard),
 731         {}
 732 };
 733
 734 struct nilfs_fs_context {
 735         unsigned long ns_mount_opt;
 736         __u64 cno;
 737 };
 738
 739 static int nilfs_parse_param(struct fs_context *fc, struct fs_parameter *param)
 740 {
 741         struct nilfs_fs_context *nilfs = fc->fs_private;
 742         int is_remount = fc->purpose == FS_CONTEXT_FOR_RECONFIGURE;
 743         struct fs_parse_result result;
 744         int opt;
 745
 746         opt = fs_parse(fc, nilfs_param_spec, param, &result);
 747         if (opt < 0)
 748                 return opt;
 749
 750         switch (opt) {
 751         case Opt_barrier:
 752                 if (result.negated)
 753                         nilfs_clear_opt(nilfs, BARRIER);
 754                 else
 755                         nilfs_set_opt(nilfs, BARRIER);
 756                 break;
 757         case Opt_order:
 758                 if (strcmp(param->string, "relaxed") == 0)
 759                         /* Ordered data semantics */
 760                         nilfs_clear_opt(nilfs, STRICT_ORDER);
 761                 else if (strcmp(param->string, "strict") == 0)
 762                         /* Strict in-order semantics */
 763                         nilfs_set_opt(nilfs, STRICT_ORDER);
 764                 else
 765                         return -EINVAL;
 766                 break;
 767         case Opt_err:
 768                 nilfs->ns_mount_opt &= ~NILFS_MOUNT_ERROR_MODE;
 769                 nilfs->ns_mount_opt |= result.uint_32;
 770                 break;
 771         case Opt_snapshot:
 772                 if (is_remount) {
 773                         struct super_block *sb = fc->root->d_sb;
 774
 775                         nilfs_err(sb,
 776                                   "\"%s\" option is invalid for remount",
 777                                   param->key);
 778                         return -EINVAL;
 779                 }
 780                 if (result.uint_64 == 0) {
 781                         nilfs_err(NULL,
 782                                   "invalid option \"cp=0\": invalid checkpoint number 0");
 783                         return -EINVAL;
 784                 }
 785                 nilfs->cno = result.uint_64;
 786                 break;
 787         case Opt_norecovery:
 788                 nilfs_set_opt(nilfs, NORECOVERY);
 789                 break;
 790         case Opt_discard:
 791                 if (result.negated)
 792                         nilfs_clear_opt(nilfs, DISCARD);
 793                 else
 794                         nilfs_set_opt(nilfs, DISCARD);
 795                 break;
 796         default:
 797                 return -EINVAL;
 798         }
 799
 800         return 0;
 801 }
 802
 803 static int nilfs_setup_super(struct super_block *sb, int is_mount)
 804 {
 805         struct the_nilfs *nilfs = sb->s_fs_info;
 806         struct nilfs_super_block **sbp;
 807         int max_mnt_count;
 808         int mnt_count;
 809
 810         /* nilfs->ns_sem must be locked by the caller. */
 811         sbp = nilfs_prepare_super(sb, 0);
 812         if (!sbp)
 813                 return -EIO;
 814
 815         if (!is_mount)
 816                 goto skip_mount_setup;
 817
 818         max_mnt_count = le16_to_cpu(sbp[0]->s_max_mnt_count);
 819         mnt_count = le16_to_cpu(sbp[0]->s_mnt_count);
 820
 821         if (nilfs->ns_mount_state & NILFS_ERROR_FS) {
 822                 nilfs_warn(sb, "mounting fs with errors");
 823 #if 0
 824         } else if (max_mnt_count >= 0 && mnt_count >= max_mnt_count) {
 825                 nilfs_warn(sb, "maximal mount count reached");
 826 #endif
 827         }
 828         if (!max_mnt_count)
 829                 sbp[0]->s_max_mnt_count = cpu_to_le16(NILFS_DFL_MAX_MNT_COUNT);
 830
 831         sbp[0]->s_mnt_count = cpu_to_le16(mnt_count + 1);
 832         sbp[0]->s_mtime = cpu_to_le64(ktime_get_real_seconds());
 833
 834 skip_mount_setup:
 835         sbp[0]->s_state =
 836                 cpu_to_le16(le16_to_cpu(sbp[0]->s_state) & ~NILFS_VALID_FS);
 837         /* synchronize sbp[1] with sbp[0] */
 838         if (sbp[1])
 839                 memcpy(sbp[1], sbp[0], nilfs->ns_sbsize);
 840         return nilfs_commit_super(sb, NILFS_SB_COMMIT_ALL);
 841 }
 842
 843 struct nilfs_super_block *nilfs_read_super_block(struct super_block *sb,
 844                                                  u64 pos, int blocksize,
 845                                                  struct buffer_head **pbh)
 846 {
 847         unsigned long long sb_index = pos;
 848         unsigned long offset;
 849
 850         offset = do_div(sb_index, blocksize);
 851         *pbh = sb_bread(sb, sb_index);
 852         if (!*pbh)
 853                 return NULL;
 854         return (struct nilfs_super_block *)((char *)(*pbh)->b_data + offset);
 855 }
 856
 857 int nilfs_store_magic(struct super_block *sb,
 858                       struct nilfs_super_block *sbp)
 859 {
 860         struct the_nilfs *nilfs = sb->s_fs_info;
 861
 862         sb->s_magic = le16_to_cpu(sbp->s_magic);
 863
 864         /* FS independent flags */
 865 #ifdef NILFS_ATIME_DISABLE
 866         sb->s_flags |= SB_NOATIME;
 867 #endif
 868
 869         nilfs->ns_resuid = le16_to_cpu(sbp->s_def_resuid);
 870         nilfs->ns_resgid = le16_to_cpu(sbp->s_def_resgid);
 871         nilfs->ns_interval = le32_to_cpu(sbp->s_c_interval);
 872         nilfs->ns_watermark = le32_to_cpu(sbp->s_c_block_max);
 873
 874         return 0;
 875 }
 876
 877 int nilfs_check_feature_compatibility(struct super_block *sb,
 878                                       struct nilfs_super_block *sbp)
 879 {
 880         __u64 features;
 881
 882         features = le64_to_cpu(sbp->s_feature_incompat) &
 883                 ~NILFS_FEATURE_INCOMPAT_SUPP;
 884         if (features) {
 885                 nilfs_err(sb,
 886                           "couldn't mount because of unsupported optional features (%llx)",
 887                           (unsigned long long)features);
 888                 return -EINVAL;
 889         }
 890         features = le64_to_cpu(sbp->s_feature_compat_ro) &
 891                 ~NILFS_FEATURE_COMPAT_RO_SUPP;
 892         if (!sb_rdonly(sb) && features) {
 893                 nilfs_err(sb,
 894                           "couldn't mount RDWR because of unsupported optional features (%llx)",
 895                           (unsigned long long)features);
 896                 return -EINVAL;
 897         }
 898         return 0;
 899 }
 900
 901 static int nilfs_get_root_dentry(struct super_block *sb,
 902                                  struct nilfs_root *root,
 903                                  struct dentry **root_dentry)
 904 {
 905         struct inode *inode;
 906         struct dentry *dentry;
 907         int ret = 0;
 908
 909         inode = nilfs_iget(sb, root, NILFS_ROOT_INO);
 910         if (IS_ERR(inode)) {
 911                 ret = PTR_ERR(inode);
 912                 nilfs_err(sb, "error %d getting root inode", ret);
 913                 goto out;
 914         }
 915         if (!S_ISDIR(inode->i_mode) || !inode->i_blocks || !inode->i_size) {
 916                 iput(inode);
 917                 nilfs_err(sb, "corrupt root inode");
 918                 ret = -EINVAL;
 919                 goto out;
 920         }
 921
 922         if (root->cno == NILFS_CPTREE_CURRENT_CNO) {
 923                 dentry = d_find_alias(inode);
 924                 if (!dentry) {
 925                         dentry = d_make_root(inode);
 926                         if (!dentry) {
 927                                 ret = -ENOMEM;
 928                                 goto failed_dentry;
 929                         }
 930                 } else {
 931                         iput(inode);
 932                 }
 933         } else {
 934                 dentry = d_obtain_root(inode);
 935                 if (IS_ERR(dentry)) {
 936                         ret = PTR_ERR(dentry);
 937                         goto failed_dentry;
 938                 }
 939         }
 940         *root_dentry = dentry;
 941  out:
 942         return ret;
 943
 944  failed_dentry:
 945         nilfs_err(sb, "error %d getting root dentry", ret);
 946         goto out;
 947 }
 948
 949 static int nilfs_attach_snapshot(struct super_block *s, __u64 cno,
 950                                  struct dentry **root_dentry)
 951 {
 952         struct the_nilfs *nilfs = s->s_fs_info;
 953         struct nilfs_root *root;
 954         int ret;
 955
 956         mutex_lock(&nilfs->ns_snapshot_mount_mutex);
 957
 958         down_read(&nilfs->ns_segctor_sem);
 959         ret = nilfs_cpfile_is_snapshot(nilfs->ns_cpfile, cno);
 960         up_read(&nilfs->ns_segctor_sem);
 961         if (ret < 0) {
 962                 ret = (ret == -ENOENT) ? -EINVAL : ret;
 963                 goto out;
 964         } else if (!ret) {
 965                 nilfs_err(s,
 966                           "The specified checkpoint is not a snapshot (checkpoint number=%llu)",
 967                           (unsigned long long)cno);
 968                 ret = -EINVAL;
 969                 goto out;
 970         }
 971
 972         ret = nilfs_attach_checkpoint(s, cno, false, &root);
 973         if (ret) {
 974                 nilfs_err(s,
 975                           "error %d while loading snapshot (checkpoint number=%llu)",
 976                           ret, (unsigned long long)cno);
 977                 goto out;
 978         }
 979         ret = nilfs_get_root_dentry(s, root, root_dentry);
 980         nilfs_put_root(root);
 981  out:
 982         mutex_unlock(&nilfs->ns_snapshot_mount_mutex);
 983         return ret;
 984 }
 985
 986 /**
 987  * nilfs_tree_is_busy() - try to shrink dentries of a checkpoint
 988  * @root_dentry: root dentry of the tree to be shrunk
 989  *
 990  * This function returns true if the tree was in-use.
 991  */
 992 static bool nilfs_tree_is_busy(struct dentry *root_dentry)
 993 {
 994         shrink_dcache_parent(root_dentry);
 995         return d_count(root_dentry) > 1;
 996 }
 997
 998 int nilfs_checkpoint_is_mounted(struct super_block *sb, __u64 cno)
 999 {
1000         struct the_nilfs *nilfs = sb->s_fs_info;
1001         struct nilfs_root *root;
1002         struct inode *inode;
1003         struct dentry *dentry;
1004         int ret;
1005
1006         if (cno > nilfs->ns_cno)
1007                 return false;
1008
1009         if (cno >= nilfs_last_cno(nilfs))
1010                 return true;    /* protect recent checkpoints */
1011
1012         ret = false;
1013         root = nilfs_lookup_root(nilfs, cno);
1014         if (root) {
1015                 inode = nilfs_ilookup(sb, root, NILFS_ROOT_INO);
1016                 if (inode) {
1017                         dentry = d_find_alias(inode);
1018                         if (dentry) {
1019                                 ret = nilfs_tree_is_busy(dentry);
1020                                 dput(dentry);
1021                         }
1022                         iput(inode);
1023                 }
1024                 nilfs_put_root(root);
1025         }
1026         return ret;
1027 }
1028
1029 /**
1030  * nilfs_fill_super() - initialize a super block instance
1031  * @sb: super_block
1032  * @fc: filesystem context
1033  *
1034  * This function is called exclusively by nilfs->ns_mount_mutex.
1035  * So, the recovery process is protected from other simultaneous mounts.
1036  */
1037 static int
1038 nilfs_fill_super(struct super_block *sb, struct fs_context *fc)
1039 {
1040         struct the_nilfs *nilfs;
1041         struct nilfs_root *fsroot;
1042         struct nilfs_fs_context *ctx = fc->fs_private;
1043         __u64 cno;
1044         int err;
1045
1046         nilfs = alloc_nilfs(sb);
1047         if (!nilfs)
1048                 return -ENOMEM;
1049
1050         sb->s_fs_info = nilfs;
1051
1052         err = init_nilfs(nilfs, sb);
1053         if (err)
1054                 goto failed_nilfs;
1055
1056         /* Copy in parsed mount options */
1057         nilfs->ns_mount_opt = ctx->ns_mount_opt;
1058
1059         sb->s_op = &nilfs_sops;
1060         sb->s_export_op = &nilfs_export_ops;
1061         sb->s_root = NULL;
1062         sb->s_time_gran = 1;
1063         sb->s_max_links = NILFS_LINK_MAX;
1064
1065         sb->s_bdi = bdi_get(sb->s_bdev->bd_disk->bdi);
1066
1067         err = load_nilfs(nilfs, sb);
1068         if (err)
1069                 goto failed_nilfs;
1070
1071         super_set_uuid(sb, nilfs->ns_sbp[0]->s_uuid,
1072                        sizeof(nilfs->ns_sbp[0]->s_uuid));
1073         super_set_sysfs_name_bdev(sb);
1074
1075         cno = nilfs_last_cno(nilfs);
1076         err = nilfs_attach_checkpoint(sb, cno, true, &fsroot);
1077         if (err) {
1078                 nilfs_err(sb,
1079                           "error %d while loading last checkpoint (checkpoint number=%llu)",
1080                           err, (unsigned long long)cno);
1081                 goto failed_unload;
1082         }
1083
1084         if (!sb_rdonly(sb)) {
1085                 err = nilfs_attach_log_writer(sb, fsroot);
1086                 if (err)
1087                         goto failed_checkpoint;
1088         }
1089
1090         err = nilfs_get_root_dentry(sb, fsroot, &sb->s_root);
1091         if (err)
1092                 goto failed_segctor;
1093
1094         nilfs_put_root(fsroot);
1095
1096         if (!sb_rdonly(sb)) {
1097                 down_write(&nilfs->ns_sem);
1098                 nilfs_setup_super(sb, true);
1099                 up_write(&nilfs->ns_sem);
1100         }
1101
1102         return 0;
1103
1104  failed_segctor:
1105         nilfs_detach_log_writer(sb);
1106
1107  failed_checkpoint:
1108         nilfs_put_root(fsroot);
1109
1110  failed_unload:
1111         nilfs_sysfs_delete_device_group(nilfs);
1112         iput(nilfs->ns_sufile);
1113         iput(nilfs->ns_cpfile);
1114         iput(nilfs->ns_dat);
1115
1116  failed_nilfs:
1117         destroy_nilfs(nilfs);
1118         return err;
1119 }
1120
1121 static int nilfs_reconfigure(struct fs_context *fc)
1122 {
1123         struct nilfs_fs_context *ctx = fc->fs_private;
1124         struct super_block *sb = fc->root->d_sb;
1125         struct the_nilfs *nilfs = sb->s_fs_info;
1126         int err;
1127
1128         sync_filesystem(sb);
1129
1130         err = -EINVAL;
1131
1132         if (!nilfs_valid_fs(nilfs)) {
1133                 nilfs_warn(sb,
1134                            "couldn't remount because the filesystem is in an incomplete recovery state");
1135                 goto ignore_opts;
1136         }
1137         if ((bool)(fc->sb_flags & SB_RDONLY) == sb_rdonly(sb))
1138                 goto out;
1139         if (fc->sb_flags & SB_RDONLY) {
1140                 sb->s_flags |= SB_RDONLY;
1141
1142                 /*
1143                  * Remounting a valid RW partition RDONLY, so set
1144                  * the RDONLY flag and then mark the partition as valid again.
1145                  */
1146                 down_write(&nilfs->ns_sem);
1147                 nilfs_cleanup_super(sb);
1148                 up_write(&nilfs->ns_sem);
1149         } else {
1150                 __u64 features;
1151                 struct nilfs_root *root;
1152
1153                 /*
1154                  * Mounting a RDONLY partition read-write, so reread and
1155                  * store the current valid flag.  (It may have been changed
1156                  * by fsck since we originally mounted the partition.)
1157                  */
1158                 down_read(&nilfs->ns_sem);
1159                 features = le64_to_cpu(nilfs->ns_sbp[0]->s_feature_compat_ro) &
1160                         ~NILFS_FEATURE_COMPAT_RO_SUPP;
1161                 up_read(&nilfs->ns_sem);
1162                 if (features) {
1163                         nilfs_warn(sb,
1164                                    "couldn't remount RDWR because of unsupported optional features (%llx)",
1165                                    (unsigned long long)features);
1166                         err = -EROFS;
1167                         goto ignore_opts;
1168                 }
1169
1170                 sb->s_flags &= ~SB_RDONLY;
1171
1172                 root = NILFS_I(d_inode(sb->s_root))->i_root;
1173                 err = nilfs_attach_log_writer(sb, root);
1174                 if (err) {
1175                         sb->s_flags |= SB_RDONLY;
1176                         goto ignore_opts;
1177                 }
1178
1179                 down_write(&nilfs->ns_sem);
1180                 nilfs_setup_super(sb, true);
1181                 up_write(&nilfs->ns_sem);
1182         }
1183  out:
1184         sb->s_flags = (sb->s_flags & ~SB_POSIXACL);
1185         /* Copy over parsed remount options */
1186         nilfs->ns_mount_opt = ctx->ns_mount_opt;
1187
1188         return 0;
1189
1190  ignore_opts:
1191         return err;
1192 }
1193
1194 static int
1195 nilfs_get_tree(struct fs_context *fc)
1196 {
1197         struct nilfs_fs_context *ctx = fc->fs_private;
1198         struct super_block *s;
1199         dev_t dev;
1200         int err;
1201
1202         if (ctx->cno && !(fc->sb_flags & SB_RDONLY)) {
1203                 nilfs_err(NULL,
1204                           "invalid option \"cp=%llu\": read-only option is not specified",
1205                           ctx->cno);
1206                 return -EINVAL;
1207         }
1208
1209         err = lookup_bdev(fc->source, &dev);
1210         if (err)
1211                 return err;
1212
1213         s = sget_dev(fc, dev);
1214         if (IS_ERR(s))
1215                 return PTR_ERR(s);
1216
1217         if (!s->s_root) {
1218                 err = setup_bdev_super(s, fc->sb_flags, fc);
1219                 if (!err)
1220                         err = nilfs_fill_super(s, fc);
1221                 if (err)
1222                         goto failed_super;
1223
1224                 s->s_flags |= SB_ACTIVE;
1225         } else if (!ctx->cno) {
1226                 if (nilfs_tree_is_busy(s->s_root)) {
1227                         if ((fc->sb_flags ^ s->s_flags) & SB_RDONLY) {
1228                                 nilfs_err(s,
1229                                           "the device already has a %s mount.",
1230                                           sb_rdonly(s) ? "read-only" : "read/write");
1231                                 err = -EBUSY;
1232                                 goto failed_super;
1233                         }
1234                 } else {
1235                         /*
1236                          * Try reconfigure to setup mount states if the current
1237                          * tree is not mounted and only snapshots use this sb.
1238                          *
1239                          * Since nilfs_reconfigure() requires fc->root to be
1240                          * set, set it first and release it on failure.
1241                          */
1242                         fc->root = dget(s->s_root);
1243                         err = nilfs_reconfigure(fc);
1244                         if (err) {
1245                                 dput(fc->root);
1246                                 fc->root = NULL;  /* prevent double release */
1247                                 goto failed_super;
1248                         }
1249                         return 0;
1250                 }
1251         }
1252
1253         if (ctx->cno) {
1254                 struct dentry *root_dentry;
1255
1256                 err = nilfs_attach_snapshot(s, ctx->cno, &root_dentry);
1257                 if (err)
1258                         goto failed_super;
1259                 fc->root = root_dentry;
1260                 return 0;
1261         }
1262
1263         fc->root = dget(s->s_root);
1264         return 0;
1265
1266  failed_super:
1267         deactivate_locked_super(s);
1268         return err;
1269 }
1270
1271 static void nilfs_free_fc(struct fs_context *fc)
1272 {
1273         kfree(fc->fs_private);
1274 }
1275
1276 static const struct fs_context_operations nilfs_context_ops = {
1277         .parse_param    = nilfs_parse_param,
1278         .get_tree       = nilfs_get_tree,
1279         .reconfigure    = nilfs_reconfigure,
1280         .free           = nilfs_free_fc,
1281 };
1282
1283 static int nilfs_init_fs_context(struct fs_context *fc)
1284 {
1285         struct nilfs_fs_context *ctx;
1286
1287         ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
1288         if (!ctx)
1289                 return -ENOMEM;
1290
1291         ctx->ns_mount_opt = NILFS_MOUNT_ERRORS_RO | NILFS_MOUNT_BARRIER;
1292         fc->fs_private = ctx;
1293         fc->ops = &nilfs_context_ops;
1294
1295         return 0;
1296 }
1297
1298 struct file_system_type nilfs_fs_type = {
1299         .owner    = THIS_MODULE,
1300         .name     = "nilfs2",
1301         .kill_sb  = kill_block_super,
1302         .fs_flags = FS_REQUIRES_DEV,
1303         .init_fs_context = nilfs_init_fs_context,
1304         .parameters = nilfs_param_spec,
1305 };
1306 MODULE_ALIAS_FS("nilfs2");
1307
1308 static void nilfs_inode_init_once(void *obj)
1309 {
1310         struct nilfs_inode_info *ii = obj;
1311
1312         INIT_LIST_HEAD(&ii->i_dirty);
1313 #ifdef CONFIG_NILFS_XATTR
1314         init_rwsem(&ii->xattr_sem);
1315 #endif
1316         inode_init_once(&ii->vfs_inode);
1317 }
1318
1319 static void nilfs_segbuf_init_once(void *obj)
1320 {
1321         memset(obj, 0, sizeof(struct nilfs_segment_buffer));
1322 }
1323
1324 static void nilfs_destroy_cachep(void)
1325 {
1326         /*
1327          * Make sure all delayed rcu free inodes are flushed before we
1328          * destroy cache.
1329          */
1330         rcu_barrier();
1331
1332         kmem_cache_destroy(nilfs_inode_cachep);
1333         kmem_cache_destroy(nilfs_transaction_cachep);
1334         kmem_cache_destroy(nilfs_segbuf_cachep);
1335         kmem_cache_destroy(nilfs_btree_path_cache);
1336 }
1337
1338 static int __init nilfs_init_cachep(void)
1339 {
1340         nilfs_inode_cachep = kmem_cache_create("nilfs2_inode_cache",
1341                         sizeof(struct nilfs_inode_info), 0,
1342                         SLAB_RECLAIM_ACCOUNT|SLAB_ACCOUNT,
1343                         nilfs_inode_init_once);
1344         if (!nilfs_inode_cachep)
1345                 goto fail;
1346
1347         nilfs_transaction_cachep = kmem_cache_create("nilfs2_transaction_cache",
1348                         sizeof(struct nilfs_transaction_info), 0,
1349                         SLAB_RECLAIM_ACCOUNT, NULL);
1350         if (!nilfs_transaction_cachep)
1351                 goto fail;
1352
1353         nilfs_segbuf_cachep = kmem_cache_create("nilfs2_segbuf_cache",
1354                         sizeof(struct nilfs_segment_buffer), 0,
1355                         SLAB_RECLAIM_ACCOUNT, nilfs_segbuf_init_once);
1356         if (!nilfs_segbuf_cachep)
1357                 goto fail;
1358
1359         nilfs_btree_path_cache = kmem_cache_create("nilfs2_btree_path_cache",
1360                         sizeof(struct nilfs_btree_path) * NILFS_BTREE_LEVEL_MAX,
1361                         0, 0, NULL);
1362         if (!nilfs_btree_path_cache)
1363                 goto fail;
1364
1365         return 0;
1366
1367 fail:
1368         nilfs_destroy_cachep();
1369         return -ENOMEM;
1370 }
1371
1372 static int __init init_nilfs_fs(void)
1373 {
1374         int err;
1375
1376         err = nilfs_init_cachep();
1377         if (err)
1378                 goto fail;
1379
1380         err = nilfs_sysfs_init();
1381         if (err)
1382                 goto free_cachep;
1383
1384         err = register_filesystem(&nilfs_fs_type);
1385         if (err)
1386                 goto deinit_sysfs_entry;
1387
1388         printk(KERN_INFO "NILFS version 2 loaded\n");
1389         return 0;
1390
1391 deinit_sysfs_entry:
1392         nilfs_sysfs_exit();
1393 free_cachep:
1394         nilfs_destroy_cachep();
1395 fail:
1396         return err;
1397 }
1398
1399 static void __exit exit_nilfs_fs(void)
1400 {
1401         nilfs_destroy_cachep();
1402         nilfs_sysfs_exit();
1403         unregister_filesystem(&nilfs_fs_type);
1404 }
1405
1406 module_init(init_nilfs_fs)
1407 module_exit(exit_nilfs_fs)