fs/nilfs2/super.c

   1 /*
   2  * super.c - NILFS module and super block management.
   3  *
   4  * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  19  *
  20  * Written by Ryusuke Konishi <ryusuke@osrg.net>
  21  */
  22 /*
  23  *  linux/fs/ext2/super.c
  24  *
  25  * Copyright (C) 1992, 1993, 1994, 1995
  26  * Remy Card (card@masi.ibp.fr)
  27  * Laboratoire MASI - Institut Blaise Pascal
  28  * Universite Pierre et Marie Curie (Paris VI)
  29  *
  30  *  from
  31  *
  32  *  linux/fs/minix/inode.c
  33  *
  34  *  Copyright (C) 1991, 1992  Linus Torvalds
  35  *
  36  *  Big-endian to little-endian byte-swapping/bitmaps by
  37  *        David S. Miller (davem@caip.rutgers.edu), 1995
  38  */
  39
  40 #include <linux/module.h>
  41 #include <linux/string.h>
  42 #include <linux/slab.h>
  43 #include <linux/init.h>
  44 #include <linux/blkdev.h>
  45 #include <linux/parser.h>
  46 #include <linux/random.h>
  47 #include <linux/crc32.h>
  48 #include <linux/vfs.h>
  49 #include <linux/writeback.h>
  50 #include <linux/kobject.h>
  51 #include <linux/seq_file.h>
  52 #include <linux/mount.h>
  53 #include "nilfs.h"
  54 #include "export.h"
  55 #include "mdt.h"
  56 #include "alloc.h"
  57 #include "btree.h"
  58 #include "btnode.h"
  59 #include "page.h"
  60 #include "cpfile.h"
  61 #include "ifile.h"
  62 #include "dat.h"
  63 #include "segment.h"
  64 #include "segbuf.h"
  65
  66 MODULE_AUTHOR("NTT Corp.");
  67 MODULE_DESCRIPTION("A New Implementation of the Log-structured Filesystem "
  68                    "(NILFS)");
  69 MODULE_LICENSE("GPL");
  70
  71 struct kmem_cache *nilfs_inode_cachep;
  72 struct kmem_cache *nilfs_transaction_cachep;
  73 struct kmem_cache *nilfs_segbuf_cachep;
  74 struct kmem_cache *nilfs_btree_path_cache;
  75
  76 static int nilfs_remount(struct super_block *sb, int *flags, char *data);
  77
  78 static void nilfs_set_error(struct nilfs_sb_info *sbi)
  79 {
  80         struct the_nilfs *nilfs = sbi->s_nilfs;
  81         struct nilfs_super_block **sbp;
  82
  83         down_write(&nilfs->ns_sem);
  84         if (!(nilfs->ns_mount_state & NILFS_ERROR_FS)) {
  85                 nilfs->ns_mount_state |= NILFS_ERROR_FS;
  86                 sbp = nilfs_prepare_super(sbi, 0);
  87                 if (likely(sbp)) {
  88                         sbp[0]->s_state |= cpu_to_le16(NILFS_ERROR_FS);
  89                         if (sbp[1])
  90                                 sbp[1]->s_state |= cpu_to_le16(NILFS_ERROR_FS);
  91                         nilfs_commit_super(sbi, NILFS_SB_COMMIT_ALL);
  92                 }
  93         }
  94         up_write(&nilfs->ns_sem);
  95 }
  96
  97 /**
  98  * nilfs_error() - report failure condition on a filesystem
  99  *
 100  * nilfs_error() sets an ERROR_FS flag on the superblock as well as
 101  * reporting an error message.  It should be called when NILFS detects
 102  * incoherences or defects of meta data on disk.  As for sustainable
 103  * errors such as a single-shot I/O error, nilfs_warning() or the printk()
 104  * function should be used instead.
 105  *
 106  * The segment constructor must not call this function because it can
 107  * kill itself.
 108  */
 109 void nilfs_error(struct super_block *sb, const char *function,
 110                  const char *fmt, ...)
 111 {
 112         struct nilfs_sb_info *sbi = NILFS_SB(sb);
 113         va_list args;
 114
 115         va_start(args, fmt);
 116         printk(KERN_CRIT "NILFS error (device %s): %s: ", sb->s_id, function);
 117         vprintk(fmt, args);
 118         printk("\n");
 119         va_end(args);
 120
 121         if (!(sb->s_flags & MS_RDONLY)) {
 122                 nilfs_set_error(sbi);
 123
 124                 if (nilfs_test_opt(sbi, ERRORS_RO)) {
 125                         printk(KERN_CRIT "Remounting filesystem read-only\n");
 126                         sb->s_flags |= MS_RDONLY;
 127                 }
 128         }
 129
 130         if (nilfs_test_opt(sbi, ERRORS_PANIC))
 131                 panic("NILFS (device %s): panic forced after error\n",
 132                       sb->s_id);
 133 }
 134
 135 void nilfs_warning(struct super_block *sb, const char *function,
 136                    const char *fmt, ...)
 137 {
 138         va_list args;
 139
 140         va_start(args, fmt);
 141         printk(KERN_WARNING "NILFS warning (device %s): %s: ",
 142                sb->s_id, function);
 143         vprintk(fmt, args);
 144         printk("\n");
 145         va_end(args);
 146 }
 147
 148
 149 struct inode *nilfs_alloc_inode_common(struct the_nilfs *nilfs)
 150 {
 151         struct nilfs_inode_info *ii;
 152
 153         ii = kmem_cache_alloc(nilfs_inode_cachep, GFP_NOFS);
 154         if (!ii)
 155                 return NULL;
 156         ii->i_bh = NULL;
 157         ii->i_state = 0;
 158         ii->i_cno = 0;
 159         ii->vfs_inode.i_version = 1;
 160         nilfs_btnode_cache_init(&ii->i_btnode_cache, nilfs->ns_bdi);
 161         return &ii->vfs_inode;
 162 }
 163
 164 struct inode *nilfs_alloc_inode(struct super_block *sb)
 165 {
 166         return nilfs_alloc_inode_common(NILFS_SB(sb)->s_nilfs);
 167 }
 168
 169 void nilfs_destroy_inode(struct inode *inode)
 170 {
 171         struct nilfs_mdt_info *mdi = NILFS_MDT(inode);
 172
 173         if (mdi) {
 174                 kfree(mdi->mi_bgl); /* kfree(NULL) is safe */
 175                 kfree(mdi);
 176         }
 177         kmem_cache_free(nilfs_inode_cachep, NILFS_I(inode));
 178 }
 179
 180 static int nilfs_sync_super(struct nilfs_sb_info *sbi, int flag)
 181 {
 182         struct the_nilfs *nilfs = sbi->s_nilfs;
 183         int err;
 184
 185  retry:
 186         set_buffer_dirty(nilfs->ns_sbh[0]);
 187
 188         if (nilfs_test_opt(sbi, BARRIER)) {
 189                 err = __sync_dirty_buffer(nilfs->ns_sbh[0],
 190                                           WRITE_SYNC | WRITE_BARRIER);
 191                 if (err == -EOPNOTSUPP) {
 192                         nilfs_warning(sbi->s_super, __func__,
 193                                       "barrier-based sync failed. "
 194                                       "disabling barriers\n");
 195                         nilfs_clear_opt(sbi, BARRIER);
 196                         goto retry;
 197                 }
 198         } else {
 199                 err = sync_dirty_buffer(nilfs->ns_sbh[0]);
 200         }
 201
 202         if (unlikely(err)) {
 203                 printk(KERN_ERR
 204                        "NILFS: unable to write superblock (err=%d)\n", err);
 205                 if (err == -EIO && nilfs->ns_sbh[1]) {
 206                         /*
 207                          * sbp[0] points to newer log than sbp[1],
 208                          * so copy sbp[0] to sbp[1] to take over sbp[0].
 209                          */
 210                         memcpy(nilfs->ns_sbp[1], nilfs->ns_sbp[0],
 211                                nilfs->ns_sbsize);
 212                         nilfs_fall_back_super_block(nilfs);
 213                         goto retry;
 214                 }
 215         } else {
 216                 struct nilfs_super_block *sbp = nilfs->ns_sbp[0];
 217
 218                 nilfs->ns_sbwcount++;
 219
 220                 /*
 221                  * The latest segment becomes trailable from the position
 222                  * written in superblock.
 223                  */
 224                 clear_nilfs_discontinued(nilfs);
 225
 226                 /* update GC protection for recent segments */
 227                 if (nilfs->ns_sbh[1]) {
 228                         if (flag == NILFS_SB_COMMIT_ALL) {
 229                                 set_buffer_dirty(nilfs->ns_sbh[1]);
 230                                 if (sync_dirty_buffer(nilfs->ns_sbh[1]) < 0)
 231                                         goto out;
 232                         }
 233                         if (le64_to_cpu(nilfs->ns_sbp[1]->s_last_cno) <
 234                             le64_to_cpu(nilfs->ns_sbp[0]->s_last_cno))
 235                                 sbp = nilfs->ns_sbp[1];
 236                 }
 237
 238                 spin_lock(&nilfs->ns_last_segment_lock);
 239                 nilfs->ns_prot_seq = le64_to_cpu(sbp->s_last_seq);
 240                 spin_unlock(&nilfs->ns_last_segment_lock);
 241         }
 242  out:
 243         return err;
 244 }
 245
 246 void nilfs_set_log_cursor(struct nilfs_super_block *sbp,
 247                           struct the_nilfs *nilfs)
 248 {
 249         sector_t nfreeblocks;
 250
 251         /* nilfs->ns_sem must be locked by the caller. */
 252         nilfs_count_free_blocks(nilfs, &nfreeblocks);
 253         sbp->s_free_blocks_count = cpu_to_le64(nfreeblocks);
 254
 255         spin_lock(&nilfs->ns_last_segment_lock);
 256         sbp->s_last_seq = cpu_to_le64(nilfs->ns_last_seq);
 257         sbp->s_last_pseg = cpu_to_le64(nilfs->ns_last_pseg);
 258         sbp->s_last_cno = cpu_to_le64(nilfs->ns_last_cno);
 259         spin_unlock(&nilfs->ns_last_segment_lock);
 260 }
 261
 262 struct nilfs_super_block **nilfs_prepare_super(struct nilfs_sb_info *sbi,
 263                                                int flip)
 264 {
 265         struct the_nilfs *nilfs = sbi->s_nilfs;
 266         struct nilfs_super_block **sbp = nilfs->ns_sbp;
 267
 268         /* nilfs->ns_sem must be locked by the caller. */
 269         if (sbp[0]->s_magic != cpu_to_le16(NILFS_SUPER_MAGIC)) {
 270                 if (sbp[1] &&
 271                     sbp[1]->s_magic == cpu_to_le16(NILFS_SUPER_MAGIC)) {
 272                         memcpy(sbp[0], sbp[1], nilfs->ns_sbsize);
 273                 } else {
 274                         printk(KERN_CRIT "NILFS: superblock broke on dev %s\n",
 275                                sbi->s_super->s_id);
 276                         return NULL;
 277                 }
 278         } else if (sbp[1] &&
 279                    sbp[1]->s_magic != cpu_to_le16(NILFS_SUPER_MAGIC)) {
 280                         memcpy(sbp[1], sbp[0], nilfs->ns_sbsize);
 281         }
 282
 283         if (flip && sbp[1])
 284                 nilfs_swap_super_block(nilfs);
 285
 286         return sbp;
 287 }
 288
 289 int nilfs_commit_super(struct nilfs_sb_info *sbi, int flag)
 290 {
 291         struct the_nilfs *nilfs = sbi->s_nilfs;
 292         struct nilfs_super_block **sbp = nilfs->ns_sbp;
 293         time_t t;
 294
 295         /* nilfs->ns_sem must be locked by the caller. */
 296         t = get_seconds();
 297         nilfs->ns_sbwtime = t;
 298         sbp[0]->s_wtime = cpu_to_le64(t);
 299         sbp[0]->s_sum = 0;
 300         sbp[0]->s_sum = cpu_to_le32(crc32_le(nilfs->ns_crc_seed,
 301                                              (unsigned char *)sbp[0],
 302                                              nilfs->ns_sbsize));
 303         if (flag == NILFS_SB_COMMIT_ALL && sbp[1]) {
 304                 sbp[1]->s_wtime = sbp[0]->s_wtime;
 305                 sbp[1]->s_sum = 0;
 306                 sbp[1]->s_sum = cpu_to_le32(crc32_le(nilfs->ns_crc_seed,
 307                                             (unsigned char *)sbp[1],
 308                                             nilfs->ns_sbsize));
 309         }
 310         clear_nilfs_sb_dirty(nilfs);
 311         return nilfs_sync_super(sbi, flag);
 312 }
 313
 314 /**
 315  * nilfs_cleanup_super() - write filesystem state for cleanup
 316  * @sbi: nilfs_sb_info to be unmounted or degraded to read-only
 317  *
 318  * This function restores state flags in the on-disk super block.
 319  * This will set "clean" flag (i.e. NILFS_VALID_FS) unless the
 320  * filesystem was not clean previously.
 321  */
 322 int nilfs_cleanup_super(struct nilfs_sb_info *sbi)
 323 {
 324         struct nilfs_super_block **sbp;
 325         int flag = NILFS_SB_COMMIT;
 326         int ret = -EIO;
 327
 328         sbp = nilfs_prepare_super(sbi, 0);
 329         if (sbp) {
 330                 sbp[0]->s_state = cpu_to_le16(sbi->s_nilfs->ns_mount_state);
 331                 nilfs_set_log_cursor(sbp[0], sbi->s_nilfs);
 332                 if (sbp[1] && sbp[0]->s_last_cno == sbp[1]->s_last_cno) {
 333                         /*
 334                          * make the "clean" flag also to the opposite
 335                          * super block if both super blocks point to
 336                          * the same checkpoint.
 337                          */
 338                         sbp[1]->s_state = sbp[0]->s_state;
 339                         flag = NILFS_SB_COMMIT_ALL;
 340                 }
 341                 ret = nilfs_commit_super(sbi, flag);
 342         }
 343         return ret;
 344 }
 345
 346 static void nilfs_put_super(struct super_block *sb)
 347 {
 348         struct nilfs_sb_info *sbi = NILFS_SB(sb);
 349         struct the_nilfs *nilfs = sbi->s_nilfs;
 350
 351         nilfs_detach_segment_constructor(sbi);
 352
 353         if (!(sb->s_flags & MS_RDONLY)) {
 354                 down_write(&nilfs->ns_sem);
 355                 nilfs_cleanup_super(sbi);
 356                 up_write(&nilfs->ns_sem);
 357         }
 358
 359         iput(nilfs->ns_sufile);
 360         iput(nilfs->ns_cpfile);
 361         iput(nilfs->ns_dat);
 362
 363         destroy_nilfs(nilfs);
 364         sbi->s_super = NULL;
 365         sb->s_fs_info = NULL;
 366         kfree(sbi);
 367 }
 368
 369 static int nilfs_sync_fs(struct super_block *sb, int wait)
 370 {
 371         struct nilfs_sb_info *sbi = NILFS_SB(sb);
 372         struct the_nilfs *nilfs = sbi->s_nilfs;
 373         struct nilfs_super_block **sbp;
 374         int err = 0;
 375
 376         /* This function is called when super block should be written back */
 377         if (wait)
 378                 err = nilfs_construct_segment(sb);
 379
 380         down_write(&nilfs->ns_sem);
 381         if (nilfs_sb_dirty(nilfs)) {
 382                 sbp = nilfs_prepare_super(sbi, nilfs_sb_will_flip(nilfs));
 383                 if (likely(sbp)) {
 384                         nilfs_set_log_cursor(sbp[0], nilfs);
 385                         nilfs_commit_super(sbi, NILFS_SB_COMMIT);
 386                 }
 387         }
 388         up_write(&nilfs->ns_sem);
 389
 390         return err;
 391 }
 392
 393 int nilfs_attach_checkpoint(struct nilfs_sb_info *sbi, __u64 cno, int curr_mnt,
 394                             struct nilfs_root **rootp)
 395 {
 396         struct the_nilfs *nilfs = sbi->s_nilfs;
 397         struct nilfs_root *root;
 398         struct nilfs_checkpoint *raw_cp;
 399         struct buffer_head *bh_cp;
 400         int err = -ENOMEM;
 401
 402         root = nilfs_find_or_create_root(
 403                 nilfs, curr_mnt ? NILFS_CPTREE_CURRENT_CNO : cno);
 404         if (!root)
 405                 return err;
 406
 407         if (root->ifile)
 408                 goto reuse; /* already attached checkpoint */
 409
 410         down_read(&nilfs->ns_segctor_sem);
 411         err = nilfs_cpfile_get_checkpoint(nilfs->ns_cpfile, cno, 0, &raw_cp,
 412                                           &bh_cp);
 413         up_read(&nilfs->ns_segctor_sem);
 414         if (unlikely(err)) {
 415                 if (err == -ENOENT || err == -EINVAL) {
 416                         printk(KERN_ERR
 417                                "NILFS: Invalid checkpoint "
 418                                "(checkpoint number=%llu)\n",
 419                                (unsigned long long)cno);
 420                         err = -EINVAL;
 421                 }
 422                 goto failed;
 423         }
 424
 425         err = nilfs_ifile_read(sbi->s_super, root, nilfs->ns_inode_size,
 426                                &raw_cp->cp_ifile_inode, &root->ifile);
 427         if (err)
 428                 goto failed_bh;
 429
 430         atomic_set(&root->inodes_count, le64_to_cpu(raw_cp->cp_inodes_count));
 431         atomic_set(&root->blocks_count, le64_to_cpu(raw_cp->cp_blocks_count));
 432
 433         nilfs_cpfile_put_checkpoint(nilfs->ns_cpfile, cno, bh_cp);
 434
 435  reuse:
 436         *rootp = root;
 437         return 0;
 438
 439  failed_bh:
 440         nilfs_cpfile_put_checkpoint(nilfs->ns_cpfile, cno, bh_cp);
 441  failed:
 442         nilfs_put_root(root);
 443
 444         return err;
 445 }
 446
 447 static int nilfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 448 {
 449         struct super_block *sb = dentry->d_sb;
 450         struct nilfs_root *root = NILFS_I(dentry->d_inode)->i_root;
 451         struct the_nilfs *nilfs = root->nilfs;
 452         u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
 453         unsigned long long blocks;
 454         unsigned long overhead;
 455         unsigned long nrsvblocks;
 456         sector_t nfreeblocks;
 457         int err;
 458
 459         /*
 460          * Compute all of the segment blocks
 461          *
 462          * The blocks before first segment and after last segment
 463          * are excluded.
 464          */
 465         blocks = nilfs->ns_blocks_per_segment * nilfs->ns_nsegments
 466                 - nilfs->ns_first_data_block;
 467         nrsvblocks = nilfs->ns_nrsvsegs * nilfs->ns_blocks_per_segment;
 468
 469         /*
 470          * Compute the overhead
 471          *
 472          * When distributing meta data blocks outside segment structure,
 473          * We must count them as the overhead.
 474          */
 475         overhead = 0;
 476
 477         err = nilfs_count_free_blocks(nilfs, &nfreeblocks);
 478         if (unlikely(err))
 479                 return err;
 480
 481         buf->f_type = NILFS_SUPER_MAGIC;
 482         buf->f_bsize = sb->s_blocksize;
 483         buf->f_blocks = blocks - overhead;
 484         buf->f_bfree = nfreeblocks;
 485         buf->f_bavail = (buf->f_bfree >= nrsvblocks) ?
 486                 (buf->f_bfree - nrsvblocks) : 0;
 487         buf->f_files = atomic_read(&root->inodes_count);
 488         buf->f_ffree = 0; /* nilfs_count_free_inodes(sb); */
 489         buf->f_namelen = NILFS_NAME_LEN;
 490         buf->f_fsid.val[0] = (u32)id;
 491         buf->f_fsid.val[1] = (u32)(id >> 32);
 492
 493         return 0;
 494 }
 495
 496 static int nilfs_show_options(struct seq_file *seq, struct vfsmount *vfs)
 497 {
 498         struct super_block *sb = vfs->mnt_sb;
 499         struct nilfs_sb_info *sbi = NILFS_SB(sb);
 500         struct nilfs_root *root = NILFS_I(vfs->mnt_root->d_inode)->i_root;
 501
 502         if (!nilfs_test_opt(sbi, BARRIER))
 503                 seq_puts(seq, ",nobarrier");
 504         if (root->cno != NILFS_CPTREE_CURRENT_CNO)
 505                 seq_printf(seq, ",cp=%llu", (unsigned long long)root->cno);
 506         if (nilfs_test_opt(sbi, ERRORS_PANIC))
 507                 seq_puts(seq, ",errors=panic");
 508         if (nilfs_test_opt(sbi, ERRORS_CONT))
 509                 seq_puts(seq, ",errors=continue");
 510         if (nilfs_test_opt(sbi, STRICT_ORDER))
 511                 seq_puts(seq, ",order=strict");
 512         if (nilfs_test_opt(sbi, NORECOVERY))
 513                 seq_puts(seq, ",norecovery");
 514         if (nilfs_test_opt(sbi, DISCARD))
 515                 seq_puts(seq, ",discard");
 516
 517         return 0;
 518 }
 519
 520 static const struct super_operations nilfs_sops = {
 521         .alloc_inode    = nilfs_alloc_inode,
 522         .destroy_inode  = nilfs_destroy_inode,
 523         .dirty_inode    = nilfs_dirty_inode,
 524         /* .write_inode    = nilfs_write_inode, */
 525         /* .put_inode      = nilfs_put_inode, */
 526         /* .drop_inode    = nilfs_drop_inode, */
 527         .evict_inode    = nilfs_evict_inode,
 528         .put_super      = nilfs_put_super,
 529         /* .write_super    = nilfs_write_super, */
 530         .sync_fs        = nilfs_sync_fs,
 531         /* .write_super_lockfs */
 532         /* .unlockfs */
 533         .statfs         = nilfs_statfs,
 534         .remount_fs     = nilfs_remount,
 535         /* .umount_begin */
 536         .show_options = nilfs_show_options
 537 };
 538
 539 enum {
 540         Opt_err_cont, Opt_err_panic, Opt_err_ro,
 541         Opt_barrier, Opt_nobarrier, Opt_snapshot, Opt_order, Opt_norecovery,
 542         Opt_discard, Opt_nodiscard, Opt_err,
 543 };
 544
 545 static match_table_t tokens = {
 546         {Opt_err_cont, "errors=continue"},
 547         {Opt_err_panic, "errors=panic"},
 548         {Opt_err_ro, "errors=remount-ro"},
 549         {Opt_barrier, "barrier"},
 550         {Opt_nobarrier, "nobarrier"},
 551         {Opt_snapshot, "cp=%u"},
 552         {Opt_order, "order=%s"},
 553         {Opt_norecovery, "norecovery"},
 554         {Opt_discard, "discard"},
 555         {Opt_nodiscard, "nodiscard"},
 556         {Opt_err, NULL}
 557 };
 558
 559 static int parse_options(char *options, struct super_block *sb, int is_remount)
 560 {
 561         struct nilfs_sb_info *sbi = NILFS_SB(sb);
 562         char *p;
 563         substring_t args[MAX_OPT_ARGS];
 564         int option;
 565
 566         if (!options)
 567                 return 1;
 568
 569         while ((p = strsep(&options, ",")) != NULL) {
 570                 int token;
 571                 if (!*p)
 572                         continue;
 573
 574                 token = match_token(p, tokens, args);
 575                 switch (token) {
 576                 case Opt_barrier:
 577                         nilfs_set_opt(sbi, BARRIER);
 578                         break;
 579                 case Opt_nobarrier:
 580                         nilfs_clear_opt(sbi, BARRIER);
 581                         break;
 582                 case Opt_order:
 583                         if (strcmp(args[0].from, "relaxed") == 0)
 584                                 /* Ordered data semantics */
 585                                 nilfs_clear_opt(sbi, STRICT_ORDER);
 586                         else if (strcmp(args[0].from, "strict") == 0)
 587                                 /* Strict in-order semantics */
 588                                 nilfs_set_opt(sbi, STRICT_ORDER);
 589                         else
 590                                 return 0;
 591                         break;
 592                 case Opt_err_panic:
 593                         nilfs_write_opt(sbi, ERROR_MODE, ERRORS_PANIC);
 594                         break;
 595                 case Opt_err_ro:
 596                         nilfs_write_opt(sbi, ERROR_MODE, ERRORS_RO);
 597                         break;
 598                 case Opt_err_cont:
 599                         nilfs_write_opt(sbi, ERROR_MODE, ERRORS_CONT);
 600                         break;
 601                 case Opt_snapshot:
 602                         if (match_int(&args[0], &option) || option <= 0)
 603                                 return 0;
 604                         if (is_remount) {
 605                                 printk(KERN_ERR
 606                                        "NILFS: \"%s\" option is invalid "
 607                                        "for remount.\n", p);
 608                                 return 0;
 609                         }
 610                         break;
 611                 case Opt_norecovery:
 612                         nilfs_set_opt(sbi, NORECOVERY);
 613                         break;
 614                 case Opt_discard:
 615                         nilfs_set_opt(sbi, DISCARD);
 616                         break;
 617                 case Opt_nodiscard:
 618                         nilfs_clear_opt(sbi, DISCARD);
 619                         break;
 620                 default:
 621                         printk(KERN_ERR
 622                                "NILFS: Unrecognized mount option \"%s\"\n", p);
 623                         return 0;
 624                 }
 625         }
 626         return 1;
 627 }
 628
 629 static inline void
 630 nilfs_set_default_options(struct nilfs_sb_info *sbi,
 631                           struct nilfs_super_block *sbp)
 632 {
 633         sbi->s_mount_opt =
 634                 NILFS_MOUNT_ERRORS_RO | NILFS_MOUNT_BARRIER;
 635 }
 636
 637 static int nilfs_setup_super(struct nilfs_sb_info *sbi)
 638 {
 639         struct the_nilfs *nilfs = sbi->s_nilfs;
 640         struct nilfs_super_block **sbp;
 641         int max_mnt_count;
 642         int mnt_count;
 643
 644         /* nilfs->ns_sem must be locked by the caller. */
 645         sbp = nilfs_prepare_super(sbi, 0);
 646         if (!sbp)
 647                 return -EIO;
 648
 649         max_mnt_count = le16_to_cpu(sbp[0]->s_max_mnt_count);
 650         mnt_count = le16_to_cpu(sbp[0]->s_mnt_count);
 651
 652         if (nilfs->ns_mount_state & NILFS_ERROR_FS) {
 653                 printk(KERN_WARNING
 654                        "NILFS warning: mounting fs with errors\n");
 655 #if 0
 656         } else if (max_mnt_count >= 0 && mnt_count >= max_mnt_count) {
 657                 printk(KERN_WARNING
 658                        "NILFS warning: maximal mount count reached\n");
 659 #endif
 660         }
 661         if (!max_mnt_count)
 662                 sbp[0]->s_max_mnt_count = cpu_to_le16(NILFS_DFL_MAX_MNT_COUNT);
 663
 664         sbp[0]->s_mnt_count = cpu_to_le16(mnt_count + 1);
 665         sbp[0]->s_state =
 666                 cpu_to_le16(le16_to_cpu(sbp[0]->s_state) & ~NILFS_VALID_FS);
 667         sbp[0]->s_mtime = cpu_to_le64(get_seconds());
 668         /* synchronize sbp[1] with sbp[0] */
 669         memcpy(sbp[1], sbp[0], nilfs->ns_sbsize);
 670         return nilfs_commit_super(sbi, NILFS_SB_COMMIT_ALL);
 671 }
 672
 673 struct nilfs_super_block *nilfs_read_super_block(struct super_block *sb,
 674                                                  u64 pos, int blocksize,
 675                                                  struct buffer_head **pbh)
 676 {
 677         unsigned long long sb_index = pos;
 678         unsigned long offset;
 679
 680         offset = do_div(sb_index, blocksize);
 681         *pbh = sb_bread(sb, sb_index);
 682         if (!*pbh)
 683                 return NULL;
 684         return (struct nilfs_super_block *)((char *)(*pbh)->b_data + offset);
 685 }
 686
 687 int nilfs_store_magic_and_option(struct super_block *sb,
 688                                  struct nilfs_super_block *sbp,
 689                                  char *data)
 690 {
 691         struct nilfs_sb_info *sbi = NILFS_SB(sb);
 692
 693         sb->s_magic = le16_to_cpu(sbp->s_magic);
 694
 695         /* FS independent flags */
 696 #ifdef NILFS_ATIME_DISABLE
 697         sb->s_flags |= MS_NOATIME;
 698 #endif
 699
 700         nilfs_set_default_options(sbi, sbp);
 701
 702         sbi->s_resuid = le16_to_cpu(sbp->s_def_resuid);
 703         sbi->s_resgid = le16_to_cpu(sbp->s_def_resgid);
 704         sbi->s_interval = le32_to_cpu(sbp->s_c_interval);
 705         sbi->s_watermark = le32_to_cpu(sbp->s_c_block_max);
 706
 707         return !parse_options(data, sb, 0) ? -EINVAL : 0 ;
 708 }
 709
 710 int nilfs_check_feature_compatibility(struct super_block *sb,
 711                                       struct nilfs_super_block *sbp)
 712 {
 713         __u64 features;
 714
 715         features = le64_to_cpu(sbp->s_feature_incompat) &
 716                 ~NILFS_FEATURE_INCOMPAT_SUPP;
 717         if (features) {
 718                 printk(KERN_ERR "NILFS: couldn't mount because of unsupported "
 719                        "optional features (%llx)\n",
 720                        (unsigned long long)features);
 721                 return -EINVAL;
 722         }
 723         features = le64_to_cpu(sbp->s_feature_compat_ro) &
 724                 ~NILFS_FEATURE_COMPAT_RO_SUPP;
 725         if (!(sb->s_flags & MS_RDONLY) && features) {
 726                 printk(KERN_ERR "NILFS: couldn't mount RDWR because of "
 727                        "unsupported optional features (%llx)\n",
 728                        (unsigned long long)features);
 729                 return -EINVAL;
 730         }
 731         return 0;
 732 }
 733
 734 static int nilfs_get_root_dentry(struct super_block *sb,
 735                                  struct nilfs_root *root,
 736                                  struct dentry **root_dentry)
 737 {
 738         struct inode *inode;
 739         struct dentry *dentry;
 740         int ret = 0;
 741
 742         inode = nilfs_iget(sb, root, NILFS_ROOT_INO);
 743         if (IS_ERR(inode)) {
 744                 printk(KERN_ERR "NILFS: get root inode failed\n");
 745                 ret = PTR_ERR(inode);
 746                 goto out;
 747         }
 748         if (!S_ISDIR(inode->i_mode) || !inode->i_blocks || !inode->i_size) {
 749                 iput(inode);
 750                 printk(KERN_ERR "NILFS: corrupt root inode.\n");
 751                 ret = -EINVAL;
 752                 goto out;
 753         }
 754
 755         if (root->cno == NILFS_CPTREE_CURRENT_CNO) {
 756                 dentry = d_find_alias(inode);
 757                 if (!dentry) {
 758                         dentry = d_alloc_root(inode);
 759                         if (!dentry) {
 760                                 iput(inode);
 761                                 ret = -ENOMEM;
 762                                 goto failed_dentry;
 763                         }
 764                 } else {
 765                         iput(inode);
 766                 }
 767         } else {
 768                 dentry = d_obtain_alias(inode);
 769                 if (IS_ERR(dentry)) {
 770                         ret = PTR_ERR(dentry);
 771                         goto failed_dentry;
 772                 }
 773         }
 774         *root_dentry = dentry;
 775  out:
 776         return ret;
 777
 778  failed_dentry:
 779         printk(KERN_ERR "NILFS: get root dentry failed\n");
 780         goto out;
 781 }
 782
 783 static int nilfs_attach_snapshot(struct super_block *s, __u64 cno,
 784                                  struct dentry **root_dentry)
 785 {
 786         struct the_nilfs *nilfs = NILFS_SB(s)->s_nilfs;
 787         struct nilfs_root *root;
 788         int ret;
 789
 790         down_read(&nilfs->ns_segctor_sem);
 791         ret = nilfs_cpfile_is_snapshot(nilfs->ns_cpfile, cno);
 792         up_read(&nilfs->ns_segctor_sem);
 793         if (ret < 0) {
 794                 ret = (ret == -ENOENT) ? -EINVAL : ret;
 795                 goto out;
 796         } else if (!ret) {
 797                 printk(KERN_ERR "NILFS: The specified checkpoint is "
 798                        "not a snapshot (checkpoint number=%llu).\n",
 799                        (unsigned long long)cno);
 800                 ret = -EINVAL;
 801                 goto out;
 802         }
 803
 804         ret = nilfs_attach_checkpoint(NILFS_SB(s), cno, false, &root);
 805         if (ret) {
 806                 printk(KERN_ERR "NILFS: error loading snapshot "
 807                        "(checkpoint number=%llu).\n",
 808                (unsigned long long)cno);
 809                 goto out;
 810         }
 811         ret = nilfs_get_root_dentry(s, root, root_dentry);
 812         nilfs_put_root(root);
 813  out:
 814         return ret;
 815 }
 816
 817 static int nilfs_tree_was_touched(struct dentry *root_dentry)
 818 {
 819         return atomic_read(&root_dentry->d_count) > 1;
 820 }
 821
 822 /**
 823  * nilfs_try_to_shrink_tree() - try to shrink dentries of a checkpoint
 824  * @root_dentry: root dentry of the tree to be shrunk
 825  *
 826  * This function returns true if the tree was in-use.
 827  */
 828 static int nilfs_try_to_shrink_tree(struct dentry *root_dentry)
 829 {
 830         if (have_submounts(root_dentry))
 831                 return true;
 832         shrink_dcache_parent(root_dentry);
 833         return nilfs_tree_was_touched(root_dentry);
 834 }
 835
 836 int nilfs_checkpoint_is_mounted(struct super_block *sb, __u64 cno)
 837 {
 838         struct the_nilfs *nilfs = NILFS_SB(sb)->s_nilfs;
 839         struct nilfs_root *root;
 840         struct inode *inode;
 841         struct dentry *dentry;
 842         int ret;
 843
 844         if (cno < 0 || cno > nilfs->ns_cno)
 845                 return false;
 846
 847         if (cno >= nilfs_last_cno(nilfs))
 848                 return true;    /* protect recent checkpoints */
 849
 850         ret = false;
 851         root = nilfs_lookup_root(NILFS_SB(sb)->s_nilfs, cno);
 852         if (root) {
 853                 inode = nilfs_ilookup(sb, root, NILFS_ROOT_INO);
 854                 if (inode) {
 855                         dentry = d_find_alias(inode);
 856                         if (dentry) {
 857                                 if (nilfs_tree_was_touched(dentry))
 858                                         ret = nilfs_try_to_shrink_tree(dentry);
 859                                 dput(dentry);
 860                         }
 861                         iput(inode);
 862                 }
 863                 nilfs_put_root(root);
 864         }
 865         return ret;
 866 }
 867
 868 /**
 869  * nilfs_fill_super() - initialize a super block instance
 870  * @sb: super_block
 871  * @data: mount options
 872  * @silent: silent mode flag
 873  *
 874  * This function is called exclusively by nilfs->ns_mount_mutex.
 875  * So, the recovery process is protected from other simultaneous mounts.
 876  */
 877 static int
 878 nilfs_fill_super(struct super_block *sb, void *data, int silent)
 879 {
 880         struct the_nilfs *nilfs;
 881         struct nilfs_sb_info *sbi;
 882         struct nilfs_root *fsroot;
 883         __u64 cno;
 884         int err;
 885
 886         sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
 887         if (!sbi)
 888                 return -ENOMEM;
 889
 890         sb->s_fs_info = sbi;
 891         sbi->s_super = sb;
 892
 893         nilfs = alloc_nilfs(sb->s_bdev);
 894         if (!nilfs) {
 895                 err = -ENOMEM;
 896                 goto failed_sbi;
 897         }
 898         sbi->s_nilfs = nilfs;
 899
 900         err = init_nilfs(nilfs, sbi, (char *)data);
 901         if (err)
 902                 goto failed_nilfs;
 903
 904         spin_lock_init(&sbi->s_inode_lock);
 905         INIT_LIST_HEAD(&sbi->s_dirty_files);
 906
 907         /*
 908          * Following initialization is overlapped because
 909          * nilfs_sb_info structure has been cleared at the beginning.
 910          * But we reserve them to keep our interest and make ready
 911          * for the future change.
 912          */
 913         get_random_bytes(&sbi->s_next_generation,
 914                          sizeof(sbi->s_next_generation));
 915         spin_lock_init(&sbi->s_next_gen_lock);
 916
 917         sb->s_op = &nilfs_sops;
 918         sb->s_export_op = &nilfs_export_ops;
 919         sb->s_root = NULL;
 920         sb->s_time_gran = 1;
 921         sb->s_bdi = nilfs->ns_bdi;
 922
 923         err = load_nilfs(nilfs, sbi);
 924         if (err)
 925                 goto failed_nilfs;
 926
 927         cno = nilfs_last_cno(nilfs);
 928         err = nilfs_attach_checkpoint(sbi, cno, true, &fsroot);
 929         if (err) {
 930                 printk(KERN_ERR "NILFS: error loading last checkpoint "
 931                        "(checkpoint number=%llu).\n", (unsigned long long)cno);
 932                 goto failed_unload;
 933         }
 934
 935         if (!(sb->s_flags & MS_RDONLY)) {
 936                 err = nilfs_attach_segment_constructor(sbi, fsroot);
 937                 if (err)
 938                         goto failed_checkpoint;
 939         }
 940
 941         err = nilfs_get_root_dentry(sb, fsroot, &sb->s_root);
 942         if (err)
 943                 goto failed_segctor;
 944
 945         nilfs_put_root(fsroot);
 946
 947         if (!(sb->s_flags & MS_RDONLY)) {
 948                 down_write(&nilfs->ns_sem);
 949                 nilfs_setup_super(sbi);
 950                 up_write(&nilfs->ns_sem);
 951         }
 952
 953         return 0;
 954
 955  failed_segctor:
 956         nilfs_detach_segment_constructor(sbi);
 957
 958  failed_checkpoint:
 959         nilfs_put_root(fsroot);
 960
 961  failed_unload:
 962         iput(nilfs->ns_sufile);
 963         iput(nilfs->ns_cpfile);
 964         iput(nilfs->ns_dat);
 965
 966  failed_nilfs:
 967         destroy_nilfs(nilfs);
 968
 969  failed_sbi:
 970         sb->s_fs_info = NULL;
 971         kfree(sbi);
 972         return err;
 973 }
 974
 975 static int nilfs_remount(struct super_block *sb, int *flags, char *data)
 976 {
 977         struct nilfs_sb_info *sbi = NILFS_SB(sb);
 978         struct the_nilfs *nilfs = sbi->s_nilfs;
 979         unsigned long old_sb_flags;
 980         struct nilfs_mount_options old_opts;
 981         int err;
 982
 983         old_sb_flags = sb->s_flags;
 984         old_opts.mount_opt = sbi->s_mount_opt;
 985
 986         if (!parse_options(data, sb, 1)) {
 987                 err = -EINVAL;
 988                 goto restore_opts;
 989         }
 990         sb->s_flags = (sb->s_flags & ~MS_POSIXACL);
 991
 992         err = -EINVAL;
 993
 994         if (!nilfs_valid_fs(nilfs)) {
 995                 printk(KERN_WARNING "NILFS (device %s): couldn't "
 996                        "remount because the filesystem is in an "
 997                        "incomplete recovery state.\n", sb->s_id);
 998                 goto restore_opts;
 999         }
1000
1001         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
1002                 goto out;
1003         if (*flags & MS_RDONLY) {
1004                 /* Shutting down the segment constructor */
1005                 nilfs_detach_segment_constructor(sbi);
1006                 sb->s_flags |= MS_RDONLY;
1007
1008                 /*
1009                  * Remounting a valid RW partition RDONLY, so set
1010                  * the RDONLY flag and then mark the partition as valid again.
1011                  */
1012                 down_write(&nilfs->ns_sem);
1013                 nilfs_cleanup_super(sbi);
1014                 up_write(&nilfs->ns_sem);
1015         } else {
1016                 __u64 features;
1017                 struct nilfs_root *root;
1018
1019                 /*
1020                  * Mounting a RDONLY partition read-write, so reread and
1021                  * store the current valid flag.  (It may have been changed
1022                  * by fsck since we originally mounted the partition.)
1023                  */
1024                 down_read(&nilfs->ns_sem);
1025                 features = le64_to_cpu(nilfs->ns_sbp[0]->s_feature_compat_ro) &
1026                         ~NILFS_FEATURE_COMPAT_RO_SUPP;
1027                 up_read(&nilfs->ns_sem);
1028                 if (features) {
1029                         printk(KERN_WARNING "NILFS (device %s): couldn't "
1030                                "remount RDWR because of unsupported optional "
1031                                "features (%llx)\n",
1032                                sb->s_id, (unsigned long long)features);
1033                         err = -EROFS;
1034                         goto restore_opts;
1035                 }
1036
1037                 sb->s_flags &= ~MS_RDONLY;
1038
1039                 root = NILFS_I(sb->s_root->d_inode)->i_root;
1040                 err = nilfs_attach_segment_constructor(sbi, root);
1041                 if (err)
1042                         goto restore_opts;
1043
1044                 down_write(&nilfs->ns_sem);
1045                 nilfs_setup_super(sbi);
1046                 up_write(&nilfs->ns_sem);
1047         }
1048  out:
1049         return 0;
1050
1051  restore_opts:
1052         sb->s_flags = old_sb_flags;
1053         sbi->s_mount_opt = old_opts.mount_opt;
1054         return err;
1055 }
1056
1057 struct nilfs_super_data {
1058         struct block_device *bdev;
1059         struct nilfs_sb_info *sbi;
1060         __u64 cno;
1061         int flags;
1062 };
1063
1064 /**
1065  * nilfs_identify - pre-read mount options needed to identify mount instance
1066  * @data: mount options
1067  * @sd: nilfs_super_data
1068  */
1069 static int nilfs_identify(char *data, struct nilfs_super_data *sd)
1070 {
1071         char *p, *options = data;
1072         substring_t args[MAX_OPT_ARGS];
1073         int option, token;
1074         int ret = 0;
1075
1076         do {
1077                 p = strsep(&options, ",");
1078                 if (p != NULL && *p) {
1079                         token = match_token(p, tokens, args);
1080                         if (token == Opt_snapshot) {
1081                                 if (!(sd->flags & MS_RDONLY))
1082                                         ret++;
1083                                 else {
1084                                         ret = match_int(&args[0], &option);
1085                                         if (!ret) {
1086                                                 if (option > 0)
1087                                                         sd->cno = option;
1088                                                 else
1089                                                         ret++;
1090                                         }
1091                                 }
1092                         }
1093                         if (ret)
1094                                 printk(KERN_ERR
1095                                        "NILFS: invalid mount option: %s\n", p);
1096                 }
1097                 if (!options)
1098                         break;
1099                 BUG_ON(options == data);
1100                 *(options - 1) = ',';
1101         } while (!ret);
1102         return ret;
1103 }
1104
1105 static int nilfs_set_bdev_super(struct super_block *s, void *data)
1106 {
1107         s->s_bdev = data;
1108         s->s_dev = s->s_bdev->bd_dev;
1109         return 0;
1110 }
1111
1112 static int nilfs_test_bdev_super(struct super_block *s, void *data)
1113 {
1114         return (void *)s->s_bdev == data;
1115 }
1116
1117 static int
1118 nilfs_get_sb(struct file_system_type *fs_type, int flags,
1119              const char *dev_name, void *data, struct vfsmount *mnt)
1120 {
1121         struct nilfs_super_data sd;
1122         struct super_block *s;
1123         fmode_t mode = FMODE_READ;
1124         struct dentry *root_dentry;
1125         int err, s_new = false;
1126
1127         if (!(flags & MS_RDONLY))
1128                 mode |= FMODE_WRITE;
1129
1130         sd.bdev = open_bdev_exclusive(dev_name, mode, fs_type);
1131         if (IS_ERR(sd.bdev))
1132                 return PTR_ERR(sd.bdev);
1133
1134         sd.cno = 0;
1135         sd.flags = flags;
1136         if (nilfs_identify((char *)data, &sd)) {
1137                 err = -EINVAL;
1138                 goto failed;
1139         }
1140
1141         s = sget(fs_type, nilfs_test_bdev_super, nilfs_set_bdev_super, sd.bdev);
1142         if (IS_ERR(s)) {
1143                 err = PTR_ERR(s);
1144                 goto failed;
1145         }
1146
1147         if (!s->s_root) {
1148                 char b[BDEVNAME_SIZE];
1149
1150                 s_new = true;
1151
1152                 /* New superblock instance created */
1153                 s->s_flags = flags;
1154                 s->s_mode = mode;
1155                 strlcpy(s->s_id, bdevname(sd.bdev, b), sizeof(s->s_id));
1156                 sb_set_blocksize(s, block_size(sd.bdev));
1157
1158                 err = nilfs_fill_super(s, data, flags & MS_SILENT ? 1 : 0);
1159                 if (err)
1160                         goto failed_super;
1161
1162                 s->s_flags |= MS_ACTIVE;
1163         } else if (!sd.cno) {
1164                 int busy = false;
1165
1166                 if (nilfs_tree_was_touched(s->s_root)) {
1167                         busy = nilfs_try_to_shrink_tree(s->s_root);
1168                         if (busy && (flags ^ s->s_flags) & MS_RDONLY) {
1169                                 printk(KERN_ERR "NILFS: the device already "
1170                                        "has a %s mount.\n",
1171                                        (s->s_flags & MS_RDONLY) ?
1172                                        "read-only" : "read/write");
1173                                 err = -EBUSY;
1174                                 goto failed_super;
1175                         }
1176                 }
1177                 if (!busy) {
1178                         /*
1179                          * Try remount to setup mount states if the current
1180                          * tree is not mounted and only snapshots use this sb.
1181                          */
1182                         err = nilfs_remount(s, &flags, data);
1183                         if (err)
1184                                 goto failed_super;
1185                 }
1186         }
1187
1188         if (sd.cno) {
1189                 err = nilfs_attach_snapshot(s, sd.cno, &root_dentry);
1190                 if (err)
1191                         goto failed_super;
1192         } else {
1193                 root_dentry = dget(s->s_root);
1194         }
1195
1196         if (!s_new)
1197                 close_bdev_exclusive(sd.bdev, mode);
1198
1199         mnt->mnt_sb = s;
1200         mnt->mnt_root = root_dentry;
1201         return 0;
1202
1203  failed_super:
1204         deactivate_locked_super(s);
1205
1206  failed:
1207         if (!s_new)
1208                 close_bdev_exclusive(sd.bdev, mode);
1209         return err;
1210 }
1211
1212 struct file_system_type nilfs_fs_type = {
1213         .owner    = THIS_MODULE,
1214         .name     = "nilfs2",
1215         .get_sb   = nilfs_get_sb,
1216         .kill_sb  = kill_block_super,
1217         .fs_flags = FS_REQUIRES_DEV,
1218 };
1219
1220 static void nilfs_inode_init_once(void *obj)
1221 {
1222         struct nilfs_inode_info *ii = obj;
1223
1224         INIT_LIST_HEAD(&ii->i_dirty);
1225 #ifdef CONFIG_NILFS_XATTR
1226         init_rwsem(&ii->xattr_sem);
1227 #endif
1228         nilfs_btnode_cache_init_once(&ii->i_btnode_cache);
1229         ii->i_bmap = &ii->i_bmap_data;
1230         inode_init_once(&ii->vfs_inode);
1231 }
1232
1233 static void nilfs_segbuf_init_once(void *obj)
1234 {
1235         memset(obj, 0, sizeof(struct nilfs_segment_buffer));
1236 }
1237
1238 static void nilfs_destroy_cachep(void)
1239 {
1240         if (nilfs_inode_cachep)
1241                 kmem_cache_destroy(nilfs_inode_cachep);
1242         if (nilfs_transaction_cachep)
1243                 kmem_cache_destroy(nilfs_transaction_cachep);
1244         if (nilfs_segbuf_cachep)
1245                 kmem_cache_destroy(nilfs_segbuf_cachep);
1246         if (nilfs_btree_path_cache)
1247                 kmem_cache_destroy(nilfs_btree_path_cache);
1248 }
1249
1250 static int __init nilfs_init_cachep(void)
1251 {
1252         nilfs_inode_cachep = kmem_cache_create("nilfs2_inode_cache",
1253                         sizeof(struct nilfs_inode_info), 0,
1254                         SLAB_RECLAIM_ACCOUNT, nilfs_inode_init_once);
1255         if (!nilfs_inode_cachep)
1256                 goto fail;
1257
1258         nilfs_transaction_cachep = kmem_cache_create("nilfs2_transaction_cache",
1259                         sizeof(struct nilfs_transaction_info), 0,
1260                         SLAB_RECLAIM_ACCOUNT, NULL);
1261         if (!nilfs_transaction_cachep)
1262                 goto fail;
1263
1264         nilfs_segbuf_cachep = kmem_cache_create("nilfs2_segbuf_cache",
1265                         sizeof(struct nilfs_segment_buffer), 0,
1266                         SLAB_RECLAIM_ACCOUNT, nilfs_segbuf_init_once);
1267         if (!nilfs_segbuf_cachep)
1268                 goto fail;
1269
1270         nilfs_btree_path_cache = kmem_cache_create("nilfs2_btree_path_cache",
1271                         sizeof(struct nilfs_btree_path) * NILFS_BTREE_LEVEL_MAX,
1272                         0, 0, NULL);
1273         if (!nilfs_btree_path_cache)
1274                 goto fail;
1275
1276         return 0;
1277
1278 fail:
1279         nilfs_destroy_cachep();
1280         return -ENOMEM;
1281 }
1282
1283 static int __init init_nilfs_fs(void)
1284 {
1285         int err;
1286
1287         err = nilfs_init_cachep();
1288         if (err)
1289                 goto fail;
1290
1291         err = register_filesystem(&nilfs_fs_type);
1292         if (err)
1293                 goto free_cachep;
1294
1295         printk(KERN_INFO "NILFS version 2 loaded\n");
1296         return 0;
1297
1298 free_cachep:
1299         nilfs_destroy_cachep();
1300 fail:
1301         return err;
1302 }
1303
1304 static void __exit exit_nilfs_fs(void)
1305 {
1306         nilfs_destroy_cachep();
1307         unregister_filesystem(&nilfs_fs_type);
1308 }
1309
1310 module_init(init_nilfs_fs)
1311 module_exit(exit_nilfs_fs)