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   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/smp_lock.h>
  49 #include <linux/vfs.h>
  50 #include <linux/writeback.h>
  51 #include <linux/kobject.h>
  52 #include <linux/exportfs.h>
  53 #include <linux/seq_file.h>
  54 #include <linux/mount.h>
  55 #include "nilfs.h"
  56 #include "mdt.h"
  57 #include "alloc.h"
  58 #include "page.h"
  59 #include "cpfile.h"
  60 #include "ifile.h"
  61 #include "dat.h"
  62 #include "segment.h"
  63 #include "segbuf.h"
  64
  65 MODULE_AUTHOR("NTT Corp.");
  66 MODULE_DESCRIPTION("A New Implementation of the Log-structured Filesystem "
  67                    "(NILFS)");
  68 MODULE_LICENSE("GPL");
  69
  70 static void nilfs_write_super(struct super_block *sb);
  71 static int nilfs_remount(struct super_block *sb, int *flags, char *data);
  72
  73 /**
  74  * nilfs_error() - report failure condition on a filesystem
  75  *
  76  * nilfs_error() sets an ERROR_FS flag on the superblock as well as
  77  * reporting an error message.  It should be called when NILFS detects
  78  * incoherences or defects of meta data on disk.  As for sustainable
  79  * errors such as a single-shot I/O error, nilfs_warning() or the printk()
  80  * function should be used instead.
  81  *
  82  * The segment constructor must not call this function because it can
  83  * kill itself.
  84  */
  85 void nilfs_error(struct super_block *sb, const char *function,
  86                  const char *fmt, ...)
  87 {
  88         struct nilfs_sb_info *sbi = NILFS_SB(sb);
  89         va_list args;
  90
  91         va_start(args, fmt);
  92         printk(KERN_CRIT "NILFS error (device %s): %s: ", sb->s_id, function);
  93         vprintk(fmt, args);
  94         printk("\n");
  95         va_end(args);
  96
  97         if (!(sb->s_flags & MS_RDONLY)) {
  98                 struct the_nilfs *nilfs = sbi->s_nilfs;
  99
 100                 if (!nilfs_test_opt(sbi, ERRORS_CONT))
 101                         nilfs_detach_segment_constructor(sbi);
 102
 103                 down_write(&nilfs->ns_sem);
 104                 if (!(nilfs->ns_mount_state & NILFS_ERROR_FS)) {
 105                         nilfs->ns_mount_state |= NILFS_ERROR_FS;
 106                         nilfs->ns_sbp[0]->s_state |=
 107                                 cpu_to_le16(NILFS_ERROR_FS);
 108                         nilfs_commit_super(sbi, 1);
 109                 }
 110                 up_write(&nilfs->ns_sem);
 111
 112                 if (nilfs_test_opt(sbi, ERRORS_RO)) {
 113                         printk(KERN_CRIT "Remounting filesystem read-only\n");
 114                         sb->s_flags |= MS_RDONLY;
 115                 }
 116         }
 117
 118         if (nilfs_test_opt(sbi, ERRORS_PANIC))
 119                 panic("NILFS (device %s): panic forced after error\n",
 120                       sb->s_id);
 121 }
 122
 123 void nilfs_warning(struct super_block *sb, const char *function,
 124                    const char *fmt, ...)
 125 {
 126         va_list args;
 127
 128         va_start(args, fmt);
 129         printk(KERN_WARNING "NILFS warning (device %s): %s: ",
 130                sb->s_id, function);
 131         vprintk(fmt, args);
 132         printk("\n");
 133         va_end(args);
 134 }
 135
 136 static struct kmem_cache *nilfs_inode_cachep;
 137
 138 struct inode *nilfs_alloc_inode_common(struct the_nilfs *nilfs)
 139 {
 140         struct nilfs_inode_info *ii;
 141
 142         ii = kmem_cache_alloc(nilfs_inode_cachep, GFP_NOFS);
 143         if (!ii)
 144                 return NULL;
 145         ii->i_bh = NULL;
 146         ii->i_state = 0;
 147         ii->vfs_inode.i_version = 1;
 148         nilfs_btnode_cache_init(&ii->i_btnode_cache, nilfs->ns_bdi);
 149         return &ii->vfs_inode;
 150 }
 151
 152 struct inode *nilfs_alloc_inode(struct super_block *sb)
 153 {
 154         return nilfs_alloc_inode_common(NILFS_SB(sb)->s_nilfs);
 155 }
 156
 157 void nilfs_destroy_inode(struct inode *inode)
 158 {
 159         kmem_cache_free(nilfs_inode_cachep, NILFS_I(inode));
 160 }
 161
 162 static void init_once(void *obj)
 163 {
 164         struct nilfs_inode_info *ii = obj;
 165
 166         INIT_LIST_HEAD(&ii->i_dirty);
 167 #ifdef CONFIG_NILFS_XATTR
 168         init_rwsem(&ii->xattr_sem);
 169 #endif
 170         nilfs_btnode_cache_init_once(&ii->i_btnode_cache);
 171         ii->i_bmap = (struct nilfs_bmap *)&ii->i_bmap_union;
 172         inode_init_once(&ii->vfs_inode);
 173 }
 174
 175 static int nilfs_init_inode_cache(void)
 176 {
 177         nilfs_inode_cachep = kmem_cache_create("nilfs2_inode_cache",
 178                                                sizeof(struct nilfs_inode_info),
 179                                                0, SLAB_RECLAIM_ACCOUNT,
 180                                                init_once);
 181
 182         return (nilfs_inode_cachep == NULL) ? -ENOMEM : 0;
 183 }
 184
 185 static inline void nilfs_destroy_inode_cache(void)
 186 {
 187         kmem_cache_destroy(nilfs_inode_cachep);
 188 }
 189
 190 static void nilfs_clear_inode(struct inode *inode)
 191 {
 192         struct nilfs_inode_info *ii = NILFS_I(inode);
 193
 194         /*
 195          * Free resources allocated in nilfs_read_inode(), here.
 196          */
 197         BUG_ON(!list_empty(&ii->i_dirty));
 198         brelse(ii->i_bh);
 199         ii->i_bh = NULL;
 200
 201         if (test_bit(NILFS_I_BMAP, &ii->i_state))
 202                 nilfs_bmap_clear(ii->i_bmap);
 203
 204         nilfs_btnode_cache_clear(&ii->i_btnode_cache);
 205 }
 206
 207 static int nilfs_sync_super(struct nilfs_sb_info *sbi, int dupsb)
 208 {
 209         struct the_nilfs *nilfs = sbi->s_nilfs;
 210         int err;
 211         int barrier_done = 0;
 212
 213         if (nilfs_test_opt(sbi, BARRIER)) {
 214                 set_buffer_ordered(nilfs->ns_sbh[0]);
 215                 barrier_done = 1;
 216         }
 217  retry:
 218         set_buffer_dirty(nilfs->ns_sbh[0]);
 219         err = sync_dirty_buffer(nilfs->ns_sbh[0]);
 220         if (err == -EOPNOTSUPP && barrier_done) {
 221                 nilfs_warning(sbi->s_super, __func__,
 222                               "barrier-based sync failed. "
 223                               "disabling barriers\n");
 224                 nilfs_clear_opt(sbi, BARRIER);
 225                 barrier_done = 0;
 226                 clear_buffer_ordered(nilfs->ns_sbh[0]);
 227                 goto retry;
 228         }
 229         if (unlikely(err)) {
 230                 printk(KERN_ERR
 231                        "NILFS: unable to write superblock (err=%d)\n", err);
 232                 if (err == -EIO && nilfs->ns_sbh[1]) {
 233                         nilfs_fall_back_super_block(nilfs);
 234                         goto retry;
 235                 }
 236         } else {
 237                 struct nilfs_super_block *sbp = nilfs->ns_sbp[0];
 238
 239                 /*
 240                  * The latest segment becomes trailable from the position
 241                  * written in superblock.
 242                  */
 243                 clear_nilfs_discontinued(nilfs);
 244
 245                 /* update GC protection for recent segments */
 246                 if (nilfs->ns_sbh[1]) {
 247                         sbp = NULL;
 248                         if (dupsb) {
 249                                 set_buffer_dirty(nilfs->ns_sbh[1]);
 250                                 if (!sync_dirty_buffer(nilfs->ns_sbh[1]))
 251                                         sbp = nilfs->ns_sbp[1];
 252                         }
 253                 }
 254                 if (sbp) {
 255                         spin_lock(&nilfs->ns_last_segment_lock);
 256                         nilfs->ns_prot_seq = le64_to_cpu(sbp->s_last_seq);
 257                         spin_unlock(&nilfs->ns_last_segment_lock);
 258                 }
 259         }
 260
 261         return err;
 262 }
 263
 264 int nilfs_commit_super(struct nilfs_sb_info *sbi, int dupsb)
 265 {
 266         struct the_nilfs *nilfs = sbi->s_nilfs;
 267         struct nilfs_super_block **sbp = nilfs->ns_sbp;
 268         sector_t nfreeblocks;
 269         time_t t;
 270         int err;
 271
 272         /* nilfs->sem must be locked by the caller. */
 273         if (sbp[0]->s_magic != NILFS_SUPER_MAGIC) {
 274                 if (sbp[1] && sbp[1]->s_magic == NILFS_SUPER_MAGIC)
 275                         nilfs_swap_super_block(nilfs);
 276                 else {
 277                         printk(KERN_CRIT "NILFS: superblock broke on dev %s\n",
 278                                sbi->s_super->s_id);
 279                         return -EIO;
 280                 }
 281         }
 282         err = nilfs_count_free_blocks(nilfs, &nfreeblocks);
 283         if (unlikely(err)) {
 284                 printk(KERN_ERR "NILFS: failed to count free blocks\n");
 285                 return err;
 286         }
 287         spin_lock(&nilfs->ns_last_segment_lock);
 288         sbp[0]->s_last_seq = cpu_to_le64(nilfs->ns_last_seq);
 289         sbp[0]->s_last_pseg = cpu_to_le64(nilfs->ns_last_pseg);
 290         sbp[0]->s_last_cno = cpu_to_le64(nilfs->ns_last_cno);
 291         spin_unlock(&nilfs->ns_last_segment_lock);
 292
 293         t = get_seconds();
 294         nilfs->ns_sbwtime[0] = t;
 295         sbp[0]->s_free_blocks_count = cpu_to_le64(nfreeblocks);
 296         sbp[0]->s_wtime = cpu_to_le64(t);
 297         sbp[0]->s_sum = 0;
 298         sbp[0]->s_sum = cpu_to_le32(crc32_le(nilfs->ns_crc_seed,
 299                                              (unsigned char *)sbp[0],
 300                                              nilfs->ns_sbsize));
 301         if (dupsb && sbp[1]) {
 302                 memcpy(sbp[1], sbp[0], nilfs->ns_sbsize);
 303                 nilfs->ns_sbwtime[1] = t;
 304         }
 305         sbi->s_super->s_dirt = 0;
 306         return nilfs_sync_super(sbi, dupsb);
 307 }
 308
 309 static void nilfs_put_super(struct super_block *sb)
 310 {
 311         struct nilfs_sb_info *sbi = NILFS_SB(sb);
 312         struct the_nilfs *nilfs = sbi->s_nilfs;
 313
 314         lock_kernel();
 315
 316         if (sb->s_dirt)
 317                 nilfs_write_super(sb);
 318
 319         nilfs_detach_segment_constructor(sbi);
 320
 321         if (!(sb->s_flags & MS_RDONLY)) {
 322                 down_write(&nilfs->ns_sem);
 323                 nilfs->ns_sbp[0]->s_state = cpu_to_le16(nilfs->ns_mount_state);
 324                 nilfs_commit_super(sbi, 1);
 325                 up_write(&nilfs->ns_sem);
 326         }
 327         down_write(&nilfs->ns_super_sem);
 328         if (nilfs->ns_current == sbi)
 329                 nilfs->ns_current = NULL;
 330         up_write(&nilfs->ns_super_sem);
 331
 332         nilfs_detach_checkpoint(sbi);
 333         put_nilfs(sbi->s_nilfs);
 334         sbi->s_super = NULL;
 335         sb->s_fs_info = NULL;
 336         nilfs_put_sbinfo(sbi);
 337
 338         unlock_kernel();
 339 }
 340
 341 /**
 342  * nilfs_write_super - write super block(s) of NILFS
 343  * @sb: super_block
 344  *
 345  * nilfs_write_super() gets a fs-dependent lock, writes super block(s), and
 346  * clears s_dirt.  This function is called in the section protected by
 347  * lock_super().
 348  *
 349  * The s_dirt flag is managed by each filesystem and we protect it by ns_sem
 350  * of the struct the_nilfs.  Lock order must be as follows:
 351  *
 352  *   1. lock_super()
 353  *   2.    down_write(&nilfs->ns_sem)
 354  *
 355  * Inside NILFS, locking ns_sem is enough to protect s_dirt and the buffer
 356  * of the super block (nilfs->ns_sbp[]).
 357  *
 358  * In most cases, VFS functions call lock_super() before calling these
 359  * methods.  So we must be careful not to bring on deadlocks when using
 360  * lock_super();  see generic_shutdown_super(), write_super(), and so on.
 361  *
 362  * Note that order of lock_kernel() and lock_super() depends on contexts
 363  * of VFS.  We should also note that lock_kernel() can be used in its
 364  * protective section and only the outermost one has an effect.
 365  */
 366 static void nilfs_write_super(struct super_block *sb)
 367 {
 368         struct nilfs_sb_info *sbi = NILFS_SB(sb);
 369         struct the_nilfs *nilfs = sbi->s_nilfs;
 370
 371         down_write(&nilfs->ns_sem);
 372         if (!(sb->s_flags & MS_RDONLY)) {
 373                 struct nilfs_super_block **sbp = nilfs->ns_sbp;
 374                 u64 t = get_seconds();
 375                 int dupsb;
 376
 377                 if (!nilfs_discontinued(nilfs) && t >= nilfs->ns_sbwtime[0] &&
 378                     t < nilfs->ns_sbwtime[0] + NILFS_SB_FREQ) {
 379                         up_write(&nilfs->ns_sem);
 380                         return;
 381                 }
 382                 dupsb = sbp[1] && t > nilfs->ns_sbwtime[1] + NILFS_ALTSB_FREQ;
 383                 nilfs_commit_super(sbi, dupsb);
 384         }
 385         sb->s_dirt = 0;
 386         up_write(&nilfs->ns_sem);
 387 }
 388
 389 static int nilfs_sync_fs(struct super_block *sb, int wait)
 390 {
 391         int err = 0;
 392
 393         nilfs_write_super(sb);
 394
 395         /* This function is called when super block should be written back */
 396         if (wait)
 397                 err = nilfs_construct_segment(sb);
 398         return err;
 399 }
 400
 401 int nilfs_attach_checkpoint(struct nilfs_sb_info *sbi, __u64 cno)
 402 {
 403         struct the_nilfs *nilfs = sbi->s_nilfs;
 404         struct nilfs_checkpoint *raw_cp;
 405         struct buffer_head *bh_cp;
 406         int err;
 407
 408         down_write(&nilfs->ns_super_sem);
 409         list_add(&sbi->s_list, &nilfs->ns_supers);
 410         up_write(&nilfs->ns_super_sem);
 411
 412         sbi->s_ifile = nilfs_mdt_new(
 413                 nilfs, sbi->s_super, NILFS_IFILE_INO, NILFS_IFILE_GFP);
 414         if (!sbi->s_ifile)
 415                 return -ENOMEM;
 416
 417         err = nilfs_palloc_init_blockgroup(sbi->s_ifile, nilfs->ns_inode_size);
 418         if (unlikely(err))
 419                 goto failed;
 420
 421         down_read(&nilfs->ns_segctor_sem);
 422         err = nilfs_cpfile_get_checkpoint(nilfs->ns_cpfile, cno, 0, &raw_cp,
 423                                           &bh_cp);
 424         up_read(&nilfs->ns_segctor_sem);
 425         if (unlikely(err)) {
 426                 if (err == -ENOENT || err == -EINVAL) {
 427                         printk(KERN_ERR
 428                                "NILFS: Invalid checkpoint "
 429                                "(checkpoint number=%llu)\n",
 430                                (unsigned long long)cno);
 431                         err = -EINVAL;
 432                 }
 433                 goto failed;
 434         }
 435         err = nilfs_read_inode_common(sbi->s_ifile, &raw_cp->cp_ifile_inode);
 436         if (unlikely(err))
 437                 goto failed_bh;
 438         atomic_set(&sbi->s_inodes_count, le64_to_cpu(raw_cp->cp_inodes_count));
 439         atomic_set(&sbi->s_blocks_count, le64_to_cpu(raw_cp->cp_blocks_count));
 440
 441         nilfs_cpfile_put_checkpoint(nilfs->ns_cpfile, cno, bh_cp);
 442         return 0;
 443
 444  failed_bh:
 445         nilfs_cpfile_put_checkpoint(nilfs->ns_cpfile, cno, bh_cp);
 446  failed:
 447         nilfs_mdt_destroy(sbi->s_ifile);
 448         sbi->s_ifile = NULL;
 449
 450         down_write(&nilfs->ns_super_sem);
 451         list_del_init(&sbi->s_list);
 452         up_write(&nilfs->ns_super_sem);
 453
 454         return err;
 455 }
 456
 457 void nilfs_detach_checkpoint(struct nilfs_sb_info *sbi)
 458 {
 459         struct the_nilfs *nilfs = sbi->s_nilfs;
 460
 461         nilfs_mdt_clear(sbi->s_ifile);
 462         nilfs_mdt_destroy(sbi->s_ifile);
 463         sbi->s_ifile = NULL;
 464         down_write(&nilfs->ns_super_sem);
 465         list_del_init(&sbi->s_list);
 466         up_write(&nilfs->ns_super_sem);
 467 }
 468
 469 static int nilfs_mark_recovery_complete(struct nilfs_sb_info *sbi)
 470 {
 471         struct the_nilfs *nilfs = sbi->s_nilfs;
 472         int err = 0;
 473
 474         down_write(&nilfs->ns_sem);
 475         if (!(nilfs->ns_mount_state & NILFS_VALID_FS)) {
 476                 nilfs->ns_mount_state |= NILFS_VALID_FS;
 477                 err = nilfs_commit_super(sbi, 1);
 478                 if (likely(!err))
 479                         printk(KERN_INFO "NILFS: recovery complete.\n");
 480         }
 481         up_write(&nilfs->ns_sem);
 482         return err;
 483 }
 484
 485 static int nilfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 486 {
 487         struct super_block *sb = dentry->d_sb;
 488         struct nilfs_sb_info *sbi = NILFS_SB(sb);
 489         struct the_nilfs *nilfs = sbi->s_nilfs;
 490         u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
 491         unsigned long long blocks;
 492         unsigned long overhead;
 493         unsigned long nrsvblocks;
 494         sector_t nfreeblocks;
 495         int err;
 496
 497         /*
 498          * Compute all of the segment blocks
 499          *
 500          * The blocks before first segment and after last segment
 501          * are excluded.
 502          */
 503         blocks = nilfs->ns_blocks_per_segment * nilfs->ns_nsegments
 504                 - nilfs->ns_first_data_block;
 505         nrsvblocks = nilfs->ns_nrsvsegs * nilfs->ns_blocks_per_segment;
 506
 507         /*
 508          * Compute the overhead
 509          *
 510          * When distributing meta data blocks outside semgent structure,
 511          * We must count them as the overhead.
 512          */
 513         overhead = 0;
 514
 515         err = nilfs_count_free_blocks(nilfs, &nfreeblocks);
 516         if (unlikely(err))
 517                 return err;
 518
 519         buf->f_type = NILFS_SUPER_MAGIC;
 520         buf->f_bsize = sb->s_blocksize;
 521         buf->f_blocks = blocks - overhead;
 522         buf->f_bfree = nfreeblocks;
 523         buf->f_bavail = (buf->f_bfree >= nrsvblocks) ?
 524                 (buf->f_bfree - nrsvblocks) : 0;
 525         buf->f_files = atomic_read(&sbi->s_inodes_count);
 526         buf->f_ffree = 0; /* nilfs_count_free_inodes(sb); */
 527         buf->f_namelen = NILFS_NAME_LEN;
 528         buf->f_fsid.val[0] = (u32)id;
 529         buf->f_fsid.val[1] = (u32)(id >> 32);
 530
 531         return 0;
 532 }
 533
 534 static int nilfs_show_options(struct seq_file *seq, struct vfsmount *vfs)
 535 {
 536         struct super_block *sb = vfs->mnt_sb;
 537         struct nilfs_sb_info *sbi = NILFS_SB(sb);
 538
 539         if (!nilfs_test_opt(sbi, BARRIER))
 540                 seq_printf(seq, ",barrier=off");
 541         if (nilfs_test_opt(sbi, SNAPSHOT))
 542                 seq_printf(seq, ",cp=%llu",
 543                            (unsigned long long int)sbi->s_snapshot_cno);
 544         if (nilfs_test_opt(sbi, ERRORS_RO))
 545                 seq_printf(seq, ",errors=remount-ro");
 546         if (nilfs_test_opt(sbi, ERRORS_PANIC))
 547                 seq_printf(seq, ",errors=panic");
 548         if (nilfs_test_opt(sbi, STRICT_ORDER))
 549                 seq_printf(seq, ",order=strict");
 550
 551         return 0;
 552 }
 553
 554 static struct super_operations nilfs_sops = {
 555         .alloc_inode    = nilfs_alloc_inode,
 556         .destroy_inode  = nilfs_destroy_inode,
 557         .dirty_inode    = nilfs_dirty_inode,
 558         /* .write_inode    = nilfs_write_inode, */
 559         /* .put_inode      = nilfs_put_inode, */
 560         /* .drop_inode    = nilfs_drop_inode, */
 561         .delete_inode   = nilfs_delete_inode,
 562         .put_super      = nilfs_put_super,
 563         .write_super    = nilfs_write_super,
 564         .sync_fs        = nilfs_sync_fs,
 565         /* .write_super_lockfs */
 566         /* .unlockfs */
 567         .statfs         = nilfs_statfs,
 568         .remount_fs     = nilfs_remount,
 569         .clear_inode    = nilfs_clear_inode,
 570         /* .umount_begin */
 571         .show_options = nilfs_show_options
 572 };
 573
 574 static struct inode *
 575 nilfs_nfs_get_inode(struct super_block *sb, u64 ino, u32 generation)
 576 {
 577         struct inode *inode;
 578
 579         if (ino < NILFS_FIRST_INO(sb) && ino != NILFS_ROOT_INO &&
 580             ino != NILFS_SKETCH_INO)
 581                 return ERR_PTR(-ESTALE);
 582
 583         inode = nilfs_iget(sb, ino);
 584         if (IS_ERR(inode))
 585                 return ERR_CAST(inode);
 586         if (generation && inode->i_generation != generation) {
 587                 iput(inode);
 588                 return ERR_PTR(-ESTALE);
 589         }
 590
 591         return inode;
 592 }
 593
 594 static struct dentry *
 595 nilfs_fh_to_dentry(struct super_block *sb, struct fid *fid, int fh_len,
 596                    int fh_type)
 597 {
 598         return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
 599                                     nilfs_nfs_get_inode);
 600 }
 601
 602 static struct dentry *
 603 nilfs_fh_to_parent(struct super_block *sb, struct fid *fid, int fh_len,
 604                    int fh_type)
 605 {
 606         return generic_fh_to_parent(sb, fid, fh_len, fh_type,
 607                                     nilfs_nfs_get_inode);
 608 }
 609
 610 static struct export_operations nilfs_export_ops = {
 611         .fh_to_dentry = nilfs_fh_to_dentry,
 612         .fh_to_parent = nilfs_fh_to_parent,
 613         .get_parent = nilfs_get_parent,
 614 };
 615
 616 enum {
 617         Opt_err_cont, Opt_err_panic, Opt_err_ro,
 618         Opt_barrier, Opt_snapshot, Opt_order,
 619         Opt_err,
 620 };
 621
 622 static match_table_t tokens = {
 623         {Opt_err_cont, "errors=continue"},
 624         {Opt_err_panic, "errors=panic"},
 625         {Opt_err_ro, "errors=remount-ro"},
 626         {Opt_barrier, "barrier=%s"},
 627         {Opt_snapshot, "cp=%u"},
 628         {Opt_order, "order=%s"},
 629         {Opt_err, NULL}
 630 };
 631
 632 static int match_bool(substring_t *s, int *result)
 633 {
 634         int len = s->to - s->from;
 635
 636         if (strncmp(s->from, "on", len) == 0)
 637                 *result = 1;
 638         else if (strncmp(s->from, "off", len) == 0)
 639                 *result = 0;
 640         else
 641                 return 1;
 642         return 0;
 643 }
 644
 645 static int parse_options(char *options, struct super_block *sb)
 646 {
 647         struct nilfs_sb_info *sbi = NILFS_SB(sb);
 648         char *p;
 649         substring_t args[MAX_OPT_ARGS];
 650         int option;
 651
 652         if (!options)
 653                 return 1;
 654
 655         while ((p = strsep(&options, ",")) != NULL) {
 656                 int token;
 657                 if (!*p)
 658                         continue;
 659
 660                 token = match_token(p, tokens, args);
 661                 switch (token) {
 662                 case Opt_barrier:
 663                         if (match_bool(&args[0], &option))
 664                                 return 0;
 665                         if (option)
 666                                 nilfs_set_opt(sbi, BARRIER);
 667                         else
 668                                 nilfs_clear_opt(sbi, BARRIER);
 669                         break;
 670                 case Opt_order:
 671                         if (strcmp(args[0].from, "relaxed") == 0)
 672                                 /* Ordered data semantics */
 673                                 nilfs_clear_opt(sbi, STRICT_ORDER);
 674                         else if (strcmp(args[0].from, "strict") == 0)
 675                                 /* Strict in-order semantics */
 676                                 nilfs_set_opt(sbi, STRICT_ORDER);
 677                         else
 678                                 return 0;
 679                         break;
 680                 case Opt_err_panic:
 681                         nilfs_write_opt(sbi, ERROR_MODE, ERRORS_PANIC);
 682                         break;
 683                 case Opt_err_ro:
 684                         nilfs_write_opt(sbi, ERROR_MODE, ERRORS_RO);
 685                         break;
 686                 case Opt_err_cont:
 687                         nilfs_write_opt(sbi, ERROR_MODE, ERRORS_CONT);
 688                         break;
 689                 case Opt_snapshot:
 690                         if (match_int(&args[0], &option) || option <= 0)
 691                                 return 0;
 692                         if (!(sb->s_flags & MS_RDONLY))
 693                                 return 0;
 694                         sbi->s_snapshot_cno = option;
 695                         nilfs_set_opt(sbi, SNAPSHOT);
 696                         break;
 697                 default:
 698                         printk(KERN_ERR
 699                                "NILFS: Unrecognized mount option \"%s\"\n", p);
 700                         return 0;
 701                 }
 702         }
 703         return 1;
 704 }
 705
 706 static inline void
 707 nilfs_set_default_options(struct nilfs_sb_info *sbi,
 708                           struct nilfs_super_block *sbp)
 709 {
 710         sbi->s_mount_opt =
 711                 NILFS_MOUNT_ERRORS_CONT | NILFS_MOUNT_BARRIER;
 712 }
 713
 714 static int nilfs_setup_super(struct nilfs_sb_info *sbi)
 715 {
 716         struct the_nilfs *nilfs = sbi->s_nilfs;
 717         struct nilfs_super_block *sbp = nilfs->ns_sbp[0];
 718         int max_mnt_count = le16_to_cpu(sbp->s_max_mnt_count);
 719         int mnt_count = le16_to_cpu(sbp->s_mnt_count);
 720
 721         /* nilfs->sem must be locked by the caller. */
 722         if (!(nilfs->ns_mount_state & NILFS_VALID_FS)) {
 723                 printk(KERN_WARNING "NILFS warning: mounting unchecked fs\n");
 724         } else if (nilfs->ns_mount_state & NILFS_ERROR_FS) {
 725                 printk(KERN_WARNING
 726                        "NILFS warning: mounting fs with errors\n");
 727 #if 0
 728         } else if (max_mnt_count >= 0 && mnt_count >= max_mnt_count) {
 729                 printk(KERN_WARNING
 730                        "NILFS warning: maximal mount count reached\n");
 731 #endif
 732         }
 733         if (!max_mnt_count)
 734                 sbp->s_max_mnt_count = cpu_to_le16(NILFS_DFL_MAX_MNT_COUNT);
 735
 736         sbp->s_mnt_count = cpu_to_le16(mnt_count + 1);
 737         sbp->s_state = cpu_to_le16(le16_to_cpu(sbp->s_state) & ~NILFS_VALID_FS);
 738         sbp->s_mtime = cpu_to_le64(get_seconds());
 739         return nilfs_commit_super(sbi, 1);
 740 }
 741
 742 struct nilfs_super_block *nilfs_read_super_block(struct super_block *sb,
 743                                                  u64 pos, int blocksize,
 744                                                  struct buffer_head **pbh)
 745 {
 746         unsigned long long sb_index = pos;
 747         unsigned long offset;
 748
 749         offset = do_div(sb_index, blocksize);
 750         *pbh = sb_bread(sb, sb_index);
 751         if (!*pbh)
 752                 return NULL;
 753         return (struct nilfs_super_block *)((char *)(*pbh)->b_data + offset);
 754 }
 755
 756 int nilfs_store_magic_and_option(struct super_block *sb,
 757                                  struct nilfs_super_block *sbp,
 758                                  char *data)
 759 {
 760         struct nilfs_sb_info *sbi = NILFS_SB(sb);
 761
 762         sb->s_magic = le16_to_cpu(sbp->s_magic);
 763
 764         /* FS independent flags */
 765 #ifdef NILFS_ATIME_DISABLE
 766         sb->s_flags |= MS_NOATIME;
 767 #endif
 768
 769         nilfs_set_default_options(sbi, sbp);
 770
 771         sbi->s_resuid = le16_to_cpu(sbp->s_def_resuid);
 772         sbi->s_resgid = le16_to_cpu(sbp->s_def_resgid);
 773         sbi->s_interval = le32_to_cpu(sbp->s_c_interval);
 774         sbi->s_watermark = le32_to_cpu(sbp->s_c_block_max);
 775
 776         return !parse_options(data, sb) ? -EINVAL : 0 ;
 777 }
 778
 779 /**
 780  * nilfs_fill_super() - initialize a super block instance
 781  * @sb: super_block
 782  * @data: mount options
 783  * @silent: silent mode flag
 784  * @nilfs: the_nilfs struct
 785  *
 786  * This function is called exclusively by nilfs->ns_mount_mutex.
 787  * So, the recovery process is protected from other simultaneous mounts.
 788  */
 789 static int
 790 nilfs_fill_super(struct super_block *sb, void *data, int silent,
 791                  struct the_nilfs *nilfs)
 792 {
 793         struct nilfs_sb_info *sbi;
 794         struct inode *root;
 795         __u64 cno;
 796         int err;
 797
 798         sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
 799         if (!sbi)
 800                 return -ENOMEM;
 801
 802         sb->s_fs_info = sbi;
 803
 804         get_nilfs(nilfs);
 805         sbi->s_nilfs = nilfs;
 806         sbi->s_super = sb;
 807         atomic_set(&sbi->s_count, 1);
 808
 809         err = init_nilfs(nilfs, sbi, (char *)data);
 810         if (err)
 811                 goto failed_sbi;
 812
 813         spin_lock_init(&sbi->s_inode_lock);
 814         INIT_LIST_HEAD(&sbi->s_dirty_files);
 815         INIT_LIST_HEAD(&sbi->s_list);
 816
 817         /*
 818          * Following initialization is overlapped because
 819          * nilfs_sb_info structure has been cleared at the beginning.
 820          * But we reserve them to keep our interest and make ready
 821          * for the future change.
 822          */
 823         get_random_bytes(&sbi->s_next_generation,
 824                          sizeof(sbi->s_next_generation));
 825         spin_lock_init(&sbi->s_next_gen_lock);
 826
 827         sb->s_op = &nilfs_sops;
 828         sb->s_export_op = &nilfs_export_ops;
 829         sb->s_root = NULL;
 830         sb->s_time_gran = 1;
 831
 832         if (!nilfs_loaded(nilfs)) {
 833                 err = load_nilfs(nilfs, sbi);
 834                 if (err)
 835                         goto failed_sbi;
 836         }
 837         cno = nilfs_last_cno(nilfs);
 838
 839         if (sb->s_flags & MS_RDONLY) {
 840                 if (nilfs_test_opt(sbi, SNAPSHOT)) {
 841                         err = nilfs_cpfile_is_snapshot(nilfs->ns_cpfile,
 842                                                        sbi->s_snapshot_cno);
 843                         if (err < 0)
 844                                 goto failed_sbi;
 845                         if (!err) {
 846                                 printk(KERN_ERR
 847                                        "NILFS: The specified checkpoint is "
 848                                        "not a snapshot "
 849                                        "(checkpoint number=%llu).\n",
 850                                        (unsigned long long)sbi->s_snapshot_cno);
 851                                 err = -EINVAL;
 852                                 goto failed_sbi;
 853                         }
 854                         cno = sbi->s_snapshot_cno;
 855                 } else
 856                         /* Read-only mount */
 857                         sbi->s_snapshot_cno = cno;
 858         }
 859
 860         err = nilfs_attach_checkpoint(sbi, cno);
 861         if (err) {
 862                 printk(KERN_ERR "NILFS: error loading a checkpoint"
 863                        " (checkpoint number=%llu).\n", (unsigned long long)cno);
 864                 goto failed_sbi;
 865         }
 866
 867         if (!(sb->s_flags & MS_RDONLY)) {
 868                 err = nilfs_attach_segment_constructor(sbi);
 869                 if (err)
 870                         goto failed_checkpoint;
 871         }
 872
 873         root = nilfs_iget(sb, NILFS_ROOT_INO);
 874         if (IS_ERR(root)) {
 875                 printk(KERN_ERR "NILFS: get root inode failed\n");
 876                 err = PTR_ERR(root);
 877                 goto failed_segctor;
 878         }
 879         if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
 880                 iput(root);
 881                 printk(KERN_ERR "NILFS: corrupt root inode.\n");
 882                 err = -EINVAL;
 883                 goto failed_segctor;
 884         }
 885         sb->s_root = d_alloc_root(root);
 886         if (!sb->s_root) {
 887                 iput(root);
 888                 printk(KERN_ERR "NILFS: get root dentry failed\n");
 889                 err = -ENOMEM;
 890                 goto failed_segctor;
 891         }
 892
 893         if (!(sb->s_flags & MS_RDONLY)) {
 894                 down_write(&nilfs->ns_sem);
 895                 nilfs_setup_super(sbi);
 896                 up_write(&nilfs->ns_sem);
 897         }
 898
 899         err = nilfs_mark_recovery_complete(sbi);
 900         if (unlikely(err)) {
 901                 printk(KERN_ERR "NILFS: recovery failed.\n");
 902                 goto failed_root;
 903         }
 904
 905         down_write(&nilfs->ns_super_sem);
 906         if (!nilfs_test_opt(sbi, SNAPSHOT))
 907                 nilfs->ns_current = sbi;
 908         up_write(&nilfs->ns_super_sem);
 909
 910         return 0;
 911
 912  failed_root:
 913         dput(sb->s_root);
 914         sb->s_root = NULL;
 915
 916  failed_segctor:
 917         nilfs_detach_segment_constructor(sbi);
 918
 919  failed_checkpoint:
 920         nilfs_detach_checkpoint(sbi);
 921
 922  failed_sbi:
 923         put_nilfs(nilfs);
 924         sb->s_fs_info = NULL;
 925         nilfs_put_sbinfo(sbi);
 926         return err;
 927 }
 928
 929 static int nilfs_remount(struct super_block *sb, int *flags, char *data)
 930 {
 931         struct nilfs_sb_info *sbi = NILFS_SB(sb);
 932         struct nilfs_super_block *sbp;
 933         struct the_nilfs *nilfs = sbi->s_nilfs;
 934         unsigned long old_sb_flags;
 935         struct nilfs_mount_options old_opts;
 936         int err;
 937
 938         lock_kernel();
 939
 940         down_write(&nilfs->ns_super_sem);
 941         old_sb_flags = sb->s_flags;
 942         old_opts.mount_opt = sbi->s_mount_opt;
 943         old_opts.snapshot_cno = sbi->s_snapshot_cno;
 944
 945         if (!parse_options(data, sb)) {
 946                 err = -EINVAL;
 947                 goto restore_opts;
 948         }
 949         sb->s_flags = (sb->s_flags & ~MS_POSIXACL);
 950
 951         if ((*flags & MS_RDONLY) &&
 952             sbi->s_snapshot_cno != old_opts.snapshot_cno) {
 953                 printk(KERN_WARNING "NILFS (device %s): couldn't "
 954                        "remount to a different snapshot. \n",
 955                        sb->s_id);
 956                 err = -EINVAL;
 957                 goto restore_opts;
 958         }
 959
 960         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
 961                 goto out;
 962         if (*flags & MS_RDONLY) {
 963                 /* Shutting down the segment constructor */
 964                 nilfs_detach_segment_constructor(sbi);
 965                 sb->s_flags |= MS_RDONLY;
 966
 967                 sbi->s_snapshot_cno = nilfs_last_cno(nilfs);
 968                 /* nilfs_set_opt(sbi, SNAPSHOT); */
 969
 970                 /*
 971                  * Remounting a valid RW partition RDONLY, so set
 972                  * the RDONLY flag and then mark the partition as valid again.
 973                  */
 974                 down_write(&nilfs->ns_sem);
 975                 sbp = nilfs->ns_sbp[0];
 976                 if (!(sbp->s_state & le16_to_cpu(NILFS_VALID_FS)) &&
 977                     (nilfs->ns_mount_state & NILFS_VALID_FS))
 978                         sbp->s_state = cpu_to_le16(nilfs->ns_mount_state);
 979                 sbp->s_mtime = cpu_to_le64(get_seconds());
 980                 nilfs_commit_super(sbi, 1);
 981                 up_write(&nilfs->ns_sem);
 982         } else {
 983                 /*
 984                  * Mounting a RDONLY partition read-write, so reread and
 985                  * store the current valid flag.  (It may have been changed
 986                  * by fsck since we originally mounted the partition.)
 987                  */
 988                 if (nilfs->ns_current && nilfs->ns_current != sbi) {
 989                         printk(KERN_WARNING "NILFS (device %s): couldn't "
 990                                "remount because an RW-mount exists.\n",
 991                                sb->s_id);
 992                         err = -EBUSY;
 993                         goto restore_opts;
 994                 }
 995                 if (sbi->s_snapshot_cno != nilfs_last_cno(nilfs)) {
 996                         printk(KERN_WARNING "NILFS (device %s): couldn't "
 997                                "remount because the current RO-mount is not "
 998                                "the latest one.\n",
 999                                sb->s_id);
1000                         err = -EINVAL;
1001                         goto restore_opts;
1002                 }
1003                 sb->s_flags &= ~MS_RDONLY;
1004                 nilfs_clear_opt(sbi, SNAPSHOT);
1005                 sbi->s_snapshot_cno = 0;
1006
1007                 err = nilfs_attach_segment_constructor(sbi);
1008                 if (err)
1009                         goto restore_opts;
1010
1011                 down_write(&nilfs->ns_sem);
1012                 nilfs_setup_super(sbi);
1013                 up_write(&nilfs->ns_sem);
1014
1015                 nilfs->ns_current = sbi;
1016         }
1017  out:
1018         up_write(&nilfs->ns_super_sem);
1019         unlock_kernel();
1020         return 0;
1021
1022  restore_opts:
1023         sb->s_flags = old_sb_flags;
1024         sbi->s_mount_opt = old_opts.mount_opt;
1025         sbi->s_snapshot_cno = old_opts.snapshot_cno;
1026         up_write(&nilfs->ns_super_sem);
1027         unlock_kernel();
1028         return err;
1029 }
1030
1031 struct nilfs_super_data {
1032         struct block_device *bdev;
1033         struct nilfs_sb_info *sbi;
1034         __u64 cno;
1035         int flags;
1036 };
1037
1038 /**
1039  * nilfs_identify - pre-read mount options needed to identify mount instance
1040  * @data: mount options
1041  * @sd: nilfs_super_data
1042  */
1043 static int nilfs_identify(char *data, struct nilfs_super_data *sd)
1044 {
1045         char *p, *options = data;
1046         substring_t args[MAX_OPT_ARGS];
1047         int option, token;
1048         int ret = 0;
1049
1050         do {
1051                 p = strsep(&options, ",");
1052                 if (p != NULL && *p) {
1053                         token = match_token(p, tokens, args);
1054                         if (token == Opt_snapshot) {
1055                                 if (!(sd->flags & MS_RDONLY))
1056                                         ret++;
1057                                 else {
1058                                         ret = match_int(&args[0], &option);
1059                                         if (!ret) {
1060                                                 if (option > 0)
1061                                                         sd->cno = option;
1062                                                 else
1063                                                         ret++;
1064                                         }
1065                                 }
1066                         }
1067                         if (ret)
1068                                 printk(KERN_ERR
1069                                        "NILFS: invalid mount option: %s\n", p);
1070                 }
1071                 if (!options)
1072                         break;
1073                 BUG_ON(options == data);
1074                 *(options - 1) = ',';
1075         } while (!ret);
1076         return ret;
1077 }
1078
1079 static int nilfs_set_bdev_super(struct super_block *s, void *data)
1080 {
1081         struct nilfs_super_data *sd = data;
1082
1083         s->s_bdev = sd->bdev;
1084         s->s_dev = s->s_bdev->bd_dev;
1085         return 0;
1086 }
1087
1088 static int nilfs_test_bdev_super(struct super_block *s, void *data)
1089 {
1090         struct nilfs_super_data *sd = data;
1091
1092         return sd->sbi && s->s_fs_info == (void *)sd->sbi;
1093 }
1094
1095 static int
1096 nilfs_get_sb(struct file_system_type *fs_type, int flags,
1097              const char *dev_name, void *data, struct vfsmount *mnt)
1098 {
1099         struct nilfs_super_data sd;
1100         struct super_block *s;
1101         struct the_nilfs *nilfs;
1102         int err, need_to_close = 1;
1103
1104         sd.bdev = open_bdev_exclusive(dev_name, flags, fs_type);
1105         if (IS_ERR(sd.bdev))
1106                 return PTR_ERR(sd.bdev);
1107
1108         /*
1109          * To get mount instance using sget() vfs-routine, NILFS needs
1110          * much more information than normal filesystems to identify mount
1111          * instance.  For snapshot mounts, not only a mount type (ro-mount
1112          * or rw-mount) but also a checkpoint number is required.
1113          */
1114         sd.cno = 0;
1115         sd.flags = flags;
1116         if (nilfs_identify((char *)data, &sd)) {
1117                 err = -EINVAL;
1118                 goto failed;
1119         }
1120
1121         nilfs = find_or_create_nilfs(sd.bdev);
1122         if (!nilfs) {
1123                 err = -ENOMEM;
1124                 goto failed;
1125         }
1126
1127         mutex_lock(&nilfs->ns_mount_mutex);
1128
1129         if (!sd.cno) {
1130                 /*
1131                  * Check if an exclusive mount exists or not.
1132                  * Snapshot mounts coexist with a current mount
1133                  * (i.e. rw-mount or ro-mount), whereas rw-mount and
1134                  * ro-mount are mutually exclusive.
1135                  */
1136                 down_read(&nilfs->ns_super_sem);
1137                 if (nilfs->ns_current &&
1138                     ((nilfs->ns_current->s_super->s_flags ^ flags)
1139                      & MS_RDONLY)) {
1140                         up_read(&nilfs->ns_super_sem);
1141                         err = -EBUSY;
1142                         goto failed_unlock;
1143                 }
1144                 up_read(&nilfs->ns_super_sem);
1145         }
1146
1147         /*
1148          * Find existing nilfs_sb_info struct
1149          */
1150         sd.sbi = nilfs_find_sbinfo(nilfs, !(flags & MS_RDONLY), sd.cno);
1151
1152         if (!sd.cno)
1153                 /* trying to get the latest checkpoint.  */
1154                 sd.cno = nilfs_last_cno(nilfs);
1155
1156         /*
1157          * Get super block instance holding the nilfs_sb_info struct.
1158          * A new instance is allocated if no existing mount is present or
1159          * existing instance has been unmounted.
1160          */
1161         s = sget(fs_type, nilfs_test_bdev_super, nilfs_set_bdev_super, &sd);
1162         if (sd.sbi)
1163                 nilfs_put_sbinfo(sd.sbi);
1164
1165         if (IS_ERR(s)) {
1166                 err = PTR_ERR(s);
1167                 goto failed_unlock;
1168         }
1169
1170         if (!s->s_root) {
1171                 char b[BDEVNAME_SIZE];
1172
1173                 /* New superblock instance created */
1174                 s->s_flags = flags;
1175                 strlcpy(s->s_id, bdevname(sd.bdev, b), sizeof(s->s_id));
1176                 sb_set_blocksize(s, block_size(sd.bdev));
1177
1178                 err = nilfs_fill_super(s, data, flags & MS_VERBOSE, nilfs);
1179                 if (err)
1180                         goto cancel_new;
1181
1182                 s->s_flags |= MS_ACTIVE;
1183                 need_to_close = 0;
1184         }
1185
1186         mutex_unlock(&nilfs->ns_mount_mutex);
1187         put_nilfs(nilfs);
1188         if (need_to_close)
1189                 close_bdev_exclusive(sd.bdev, flags);
1190         simple_set_mnt(mnt, s);
1191         return 0;
1192
1193  failed_unlock:
1194         mutex_unlock(&nilfs->ns_mount_mutex);
1195         put_nilfs(nilfs);
1196  failed:
1197         close_bdev_exclusive(sd.bdev, flags);
1198
1199         return err;
1200
1201  cancel_new:
1202         /* Abandoning the newly allocated superblock */
1203         mutex_unlock(&nilfs->ns_mount_mutex);
1204         put_nilfs(nilfs);
1205         up_write(&s->s_umount);
1206         deactivate_super(s);
1207         /*
1208          * deactivate_super() invokes close_bdev_exclusive().
1209          * We must finish all post-cleaning before this call;
1210          * put_nilfs() needs the block device.
1211          */
1212         return err;
1213 }
1214
1215 struct file_system_type nilfs_fs_type = {
1216         .owner    = THIS_MODULE,
1217         .name     = "nilfs2",
1218         .get_sb   = nilfs_get_sb,
1219         .kill_sb  = kill_block_super,
1220         .fs_flags = FS_REQUIRES_DEV,
1221 };
1222
1223 static int __init init_nilfs_fs(void)
1224 {
1225         int err;
1226
1227         err = nilfs_init_inode_cache();
1228         if (err)
1229                 goto failed;
1230
1231         err = nilfs_init_transaction_cache();
1232         if (err)
1233                 goto failed_inode_cache;
1234
1235         err = nilfs_init_segbuf_cache();
1236         if (err)
1237                 goto failed_transaction_cache;
1238
1239         err = nilfs_btree_path_cache_init();
1240         if (err)
1241                 goto failed_segbuf_cache;
1242
1243         err = register_filesystem(&nilfs_fs_type);
1244         if (err)
1245                 goto failed_btree_path_cache;
1246
1247         return 0;
1248
1249  failed_btree_path_cache:
1250         nilfs_btree_path_cache_destroy();
1251
1252  failed_segbuf_cache:
1253         nilfs_destroy_segbuf_cache();
1254
1255  failed_transaction_cache:
1256         nilfs_destroy_transaction_cache();
1257
1258  failed_inode_cache:
1259         nilfs_destroy_inode_cache();
1260
1261  failed:
1262         return err;
1263 }
1264
1265 static void __exit exit_nilfs_fs(void)
1266 {
1267         nilfs_destroy_segbuf_cache();
1268         nilfs_destroy_transaction_cache();
1269         nilfs_destroy_inode_cache();
1270         nilfs_btree_path_cache_destroy();
1271         unregister_filesystem(&nilfs_fs_type);
1272 }
1273
1274 module_init(init_nilfs_fs)
1275 module_exit(exit_nilfs_fs)