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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         nilfs_detach_segment_constructor(sbi);
 317
 318         if (!(sb->s_flags & MS_RDONLY)) {
 319                 down_write(&nilfs->ns_sem);
 320                 nilfs->ns_sbp[0]->s_state = cpu_to_le16(nilfs->ns_mount_state);
 321                 nilfs_commit_super(sbi, 1);
 322                 up_write(&nilfs->ns_sem);
 323         }
 324         down_write(&nilfs->ns_super_sem);
 325         if (nilfs->ns_current == sbi)
 326                 nilfs->ns_current = NULL;
 327         up_write(&nilfs->ns_super_sem);
 328
 329         nilfs_detach_checkpoint(sbi);
 330         put_nilfs(sbi->s_nilfs);
 331         sbi->s_super = NULL;
 332         sb->s_fs_info = NULL;
 333         nilfs_put_sbinfo(sbi);
 334
 335         unlock_kernel();
 336 }
 337
 338 /**
 339  * nilfs_write_super - write super block(s) of NILFS
 340  * @sb: super_block
 341  *
 342  * nilfs_write_super() gets a fs-dependent lock, writes super block(s), and
 343  * clears s_dirt.  This function is called in the section protected by
 344  * lock_super().
 345  *
 346  * The s_dirt flag is managed by each filesystem and we protect it by ns_sem
 347  * of the struct the_nilfs.  Lock order must be as follows:
 348  *
 349  *   1. lock_super()
 350  *   2.    down_write(&nilfs->ns_sem)
 351  *
 352  * Inside NILFS, locking ns_sem is enough to protect s_dirt and the buffer
 353  * of the super block (nilfs->ns_sbp[]).
 354  *
 355  * In most cases, VFS functions call lock_super() before calling these
 356  * methods.  So we must be careful not to bring on deadlocks when using
 357  * lock_super();  see generic_shutdown_super(), write_super(), and so on.
 358  *
 359  * Note that order of lock_kernel() and lock_super() depends on contexts
 360  * of VFS.  We should also note that lock_kernel() can be used in its
 361  * protective section and only the outermost one has an effect.
 362  */
 363 static void nilfs_write_super(struct super_block *sb)
 364 {
 365         struct nilfs_sb_info *sbi = NILFS_SB(sb);
 366         struct the_nilfs *nilfs = sbi->s_nilfs;
 367
 368         down_write(&nilfs->ns_sem);
 369         if (!(sb->s_flags & MS_RDONLY)) {
 370                 if (!nilfs_discontinued(nilfs) &&
 371                     !nilfs_sb_need_update(nilfs)) {
 372                         up_write(&nilfs->ns_sem);
 373                         return;
 374                 }
 375                 nilfs_commit_super(sbi, nilfs_altsb_need_update(nilfs));
 376         }
 377         sb->s_dirt = 0;
 378         up_write(&nilfs->ns_sem);
 379 }
 380
 381 static int nilfs_sync_fs(struct super_block *sb, int wait)
 382 {
 383         struct nilfs_sb_info *sbi = NILFS_SB(sb);
 384         struct the_nilfs *nilfs = sbi->s_nilfs;
 385         int err = 0;
 386
 387         /* This function is called when super block should be written back */
 388         if (wait)
 389                 err = nilfs_construct_segment(sb);
 390
 391         down_write(&nilfs->ns_sem);
 392         if (sb->s_dirt)
 393                 nilfs_commit_super(sbi, 1);
 394         up_write(&nilfs->ns_sem);
 395
 396         return err;
 397 }
 398
 399 int nilfs_attach_checkpoint(struct nilfs_sb_info *sbi, __u64 cno)
 400 {
 401         struct the_nilfs *nilfs = sbi->s_nilfs;
 402         struct nilfs_checkpoint *raw_cp;
 403         struct buffer_head *bh_cp;
 404         int err;
 405
 406         down_write(&nilfs->ns_super_sem);
 407         list_add(&sbi->s_list, &nilfs->ns_supers);
 408         up_write(&nilfs->ns_super_sem);
 409
 410         sbi->s_ifile = nilfs_mdt_new(
 411                 nilfs, sbi->s_super, NILFS_IFILE_INO, NILFS_IFILE_GFP);
 412         if (!sbi->s_ifile)
 413                 return -ENOMEM;
 414
 415         err = nilfs_palloc_init_blockgroup(sbi->s_ifile, nilfs->ns_inode_size);
 416         if (unlikely(err))
 417                 goto failed;
 418
 419         down_read(&nilfs->ns_segctor_sem);
 420         err = nilfs_cpfile_get_checkpoint(nilfs->ns_cpfile, cno, 0, &raw_cp,
 421                                           &bh_cp);
 422         up_read(&nilfs->ns_segctor_sem);
 423         if (unlikely(err)) {
 424                 if (err == -ENOENT || err == -EINVAL) {
 425                         printk(KERN_ERR
 426                                "NILFS: Invalid checkpoint "
 427                                "(checkpoint number=%llu)\n",
 428                                (unsigned long long)cno);
 429                         err = -EINVAL;
 430                 }
 431                 goto failed;
 432         }
 433         err = nilfs_read_inode_common(sbi->s_ifile, &raw_cp->cp_ifile_inode);
 434         if (unlikely(err))
 435                 goto failed_bh;
 436         atomic_set(&sbi->s_inodes_count, le64_to_cpu(raw_cp->cp_inodes_count));
 437         atomic_set(&sbi->s_blocks_count, le64_to_cpu(raw_cp->cp_blocks_count));
 438
 439         nilfs_cpfile_put_checkpoint(nilfs->ns_cpfile, cno, bh_cp);
 440         return 0;
 441
 442  failed_bh:
 443         nilfs_cpfile_put_checkpoint(nilfs->ns_cpfile, cno, bh_cp);
 444  failed:
 445         nilfs_mdt_destroy(sbi->s_ifile);
 446         sbi->s_ifile = NULL;
 447
 448         down_write(&nilfs->ns_super_sem);
 449         list_del_init(&sbi->s_list);
 450         up_write(&nilfs->ns_super_sem);
 451
 452         return err;
 453 }
 454
 455 void nilfs_detach_checkpoint(struct nilfs_sb_info *sbi)
 456 {
 457         struct the_nilfs *nilfs = sbi->s_nilfs;
 458
 459         nilfs_mdt_clear(sbi->s_ifile);
 460         nilfs_mdt_destroy(sbi->s_ifile);
 461         sbi->s_ifile = NULL;
 462         down_write(&nilfs->ns_super_sem);
 463         list_del_init(&sbi->s_list);
 464         up_write(&nilfs->ns_super_sem);
 465 }
 466
 467 static int nilfs_mark_recovery_complete(struct nilfs_sb_info *sbi)
 468 {
 469         struct the_nilfs *nilfs = sbi->s_nilfs;
 470         int err = 0;
 471
 472         down_write(&nilfs->ns_sem);
 473         if (!(nilfs->ns_mount_state & NILFS_VALID_FS)) {
 474                 nilfs->ns_mount_state |= NILFS_VALID_FS;
 475                 err = nilfs_commit_super(sbi, 1);
 476                 if (likely(!err))
 477                         printk(KERN_INFO "NILFS: recovery complete.\n");
 478         }
 479         up_write(&nilfs->ns_sem);
 480         return err;
 481 }
 482
 483 static int nilfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 484 {
 485         struct super_block *sb = dentry->d_sb;
 486         struct nilfs_sb_info *sbi = NILFS_SB(sb);
 487         struct the_nilfs *nilfs = sbi->s_nilfs;
 488         u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
 489         unsigned long long blocks;
 490         unsigned long overhead;
 491         unsigned long nrsvblocks;
 492         sector_t nfreeblocks;
 493         int err;
 494
 495         /*
 496          * Compute all of the segment blocks
 497          *
 498          * The blocks before first segment and after last segment
 499          * are excluded.
 500          */
 501         blocks = nilfs->ns_blocks_per_segment * nilfs->ns_nsegments
 502                 - nilfs->ns_first_data_block;
 503         nrsvblocks = nilfs->ns_nrsvsegs * nilfs->ns_blocks_per_segment;
 504
 505         /*
 506          * Compute the overhead
 507          *
 508          * When distributing meta data blocks outside semgent structure,
 509          * We must count them as the overhead.
 510          */
 511         overhead = 0;
 512
 513         err = nilfs_count_free_blocks(nilfs, &nfreeblocks);
 514         if (unlikely(err))
 515                 return err;
 516
 517         buf->f_type = NILFS_SUPER_MAGIC;
 518         buf->f_bsize = sb->s_blocksize;
 519         buf->f_blocks = blocks - overhead;
 520         buf->f_bfree = nfreeblocks;
 521         buf->f_bavail = (buf->f_bfree >= nrsvblocks) ?
 522                 (buf->f_bfree - nrsvblocks) : 0;
 523         buf->f_files = atomic_read(&sbi->s_inodes_count);
 524         buf->f_ffree = 0; /* nilfs_count_free_inodes(sb); */
 525         buf->f_namelen = NILFS_NAME_LEN;
 526         buf->f_fsid.val[0] = (u32)id;
 527         buf->f_fsid.val[1] = (u32)(id >> 32);
 528
 529         return 0;
 530 }
 531
 532 static int nilfs_show_options(struct seq_file *seq, struct vfsmount *vfs)
 533 {
 534         struct super_block *sb = vfs->mnt_sb;
 535         struct nilfs_sb_info *sbi = NILFS_SB(sb);
 536
 537         if (!nilfs_test_opt(sbi, BARRIER))
 538                 seq_printf(seq, ",barrier=off");
 539         if (nilfs_test_opt(sbi, SNAPSHOT))
 540                 seq_printf(seq, ",cp=%llu",
 541                            (unsigned long long int)sbi->s_snapshot_cno);
 542         if (nilfs_test_opt(sbi, ERRORS_RO))
 543                 seq_printf(seq, ",errors=remount-ro");
 544         if (nilfs_test_opt(sbi, ERRORS_PANIC))
 545                 seq_printf(seq, ",errors=panic");
 546         if (nilfs_test_opt(sbi, STRICT_ORDER))
 547                 seq_printf(seq, ",order=strict");
 548
 549         return 0;
 550 }
 551
 552 static struct super_operations nilfs_sops = {
 553         .alloc_inode    = nilfs_alloc_inode,
 554         .destroy_inode  = nilfs_destroy_inode,
 555         .dirty_inode    = nilfs_dirty_inode,
 556         /* .write_inode    = nilfs_write_inode, */
 557         /* .put_inode      = nilfs_put_inode, */
 558         /* .drop_inode    = nilfs_drop_inode, */
 559         .delete_inode   = nilfs_delete_inode,
 560         .put_super      = nilfs_put_super,
 561         .write_super    = nilfs_write_super,
 562         .sync_fs        = nilfs_sync_fs,
 563         /* .write_super_lockfs */
 564         /* .unlockfs */
 565         .statfs         = nilfs_statfs,
 566         .remount_fs     = nilfs_remount,
 567         .clear_inode    = nilfs_clear_inode,
 568         /* .umount_begin */
 569         .show_options = nilfs_show_options
 570 };
 571
 572 static struct inode *
 573 nilfs_nfs_get_inode(struct super_block *sb, u64 ino, u32 generation)
 574 {
 575         struct inode *inode;
 576
 577         if (ino < NILFS_FIRST_INO(sb) && ino != NILFS_ROOT_INO &&
 578             ino != NILFS_SKETCH_INO)
 579                 return ERR_PTR(-ESTALE);
 580
 581         inode = nilfs_iget(sb, ino);
 582         if (IS_ERR(inode))
 583                 return ERR_CAST(inode);
 584         if (generation && inode->i_generation != generation) {
 585                 iput(inode);
 586                 return ERR_PTR(-ESTALE);
 587         }
 588
 589         return inode;
 590 }
 591
 592 static struct dentry *
 593 nilfs_fh_to_dentry(struct super_block *sb, struct fid *fid, int fh_len,
 594                    int fh_type)
 595 {
 596         return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
 597                                     nilfs_nfs_get_inode);
 598 }
 599
 600 static struct dentry *
 601 nilfs_fh_to_parent(struct super_block *sb, struct fid *fid, int fh_len,
 602                    int fh_type)
 603 {
 604         return generic_fh_to_parent(sb, fid, fh_len, fh_type,
 605                                     nilfs_nfs_get_inode);
 606 }
 607
 608 static struct export_operations nilfs_export_ops = {
 609         .fh_to_dentry = nilfs_fh_to_dentry,
 610         .fh_to_parent = nilfs_fh_to_parent,
 611         .get_parent = nilfs_get_parent,
 612 };
 613
 614 enum {
 615         Opt_err_cont, Opt_err_panic, Opt_err_ro,
 616         Opt_barrier, Opt_snapshot, Opt_order,
 617         Opt_err,
 618 };
 619
 620 static match_table_t tokens = {
 621         {Opt_err_cont, "errors=continue"},
 622         {Opt_err_panic, "errors=panic"},
 623         {Opt_err_ro, "errors=remount-ro"},
 624         {Opt_barrier, "barrier=%s"},
 625         {Opt_snapshot, "cp=%u"},
 626         {Opt_order, "order=%s"},
 627         {Opt_err, NULL}
 628 };
 629
 630 static int match_bool(substring_t *s, int *result)
 631 {
 632         int len = s->to - s->from;
 633
 634         if (strncmp(s->from, "on", len) == 0)
 635                 *result = 1;
 636         else if (strncmp(s->from, "off", len) == 0)
 637                 *result = 0;
 638         else
 639                 return 1;
 640         return 0;
 641 }
 642
 643 static int parse_options(char *options, struct super_block *sb)
 644 {
 645         struct nilfs_sb_info *sbi = NILFS_SB(sb);
 646         char *p;
 647         substring_t args[MAX_OPT_ARGS];
 648         int option;
 649
 650         if (!options)
 651                 return 1;
 652
 653         while ((p = strsep(&options, ",")) != NULL) {
 654                 int token;
 655                 if (!*p)
 656                         continue;
 657
 658                 token = match_token(p, tokens, args);
 659                 switch (token) {
 660                 case Opt_barrier:
 661                         if (match_bool(&args[0], &option))
 662                                 return 0;
 663                         if (option)
 664                                 nilfs_set_opt(sbi, BARRIER);
 665                         else
 666                                 nilfs_clear_opt(sbi, BARRIER);
 667                         break;
 668                 case Opt_order:
 669                         if (strcmp(args[0].from, "relaxed") == 0)
 670                                 /* Ordered data semantics */
 671                                 nilfs_clear_opt(sbi, STRICT_ORDER);
 672                         else if (strcmp(args[0].from, "strict") == 0)
 673                                 /* Strict in-order semantics */
 674                                 nilfs_set_opt(sbi, STRICT_ORDER);
 675                         else
 676                                 return 0;
 677                         break;
 678                 case Opt_err_panic:
 679                         nilfs_write_opt(sbi, ERROR_MODE, ERRORS_PANIC);
 680                         break;
 681                 case Opt_err_ro:
 682                         nilfs_write_opt(sbi, ERROR_MODE, ERRORS_RO);
 683                         break;
 684                 case Opt_err_cont:
 685                         nilfs_write_opt(sbi, ERROR_MODE, ERRORS_CONT);
 686                         break;
 687                 case Opt_snapshot:
 688                         if (match_int(&args[0], &option) || option <= 0)
 689                                 return 0;
 690                         if (!(sb->s_flags & MS_RDONLY))
 691                                 return 0;
 692                         sbi->s_snapshot_cno = option;
 693                         nilfs_set_opt(sbi, SNAPSHOT);
 694                         break;
 695                 default:
 696                         printk(KERN_ERR
 697                                "NILFS: Unrecognized mount option \"%s\"\n", p);
 698                         return 0;
 699                 }
 700         }
 701         return 1;
 702 }
 703
 704 static inline void
 705 nilfs_set_default_options(struct nilfs_sb_info *sbi,
 706                           struct nilfs_super_block *sbp)
 707 {
 708         sbi->s_mount_opt =
 709                 NILFS_MOUNT_ERRORS_CONT | NILFS_MOUNT_BARRIER;
 710 }
 711
 712 static int nilfs_setup_super(struct nilfs_sb_info *sbi)
 713 {
 714         struct the_nilfs *nilfs = sbi->s_nilfs;
 715         struct nilfs_super_block *sbp = nilfs->ns_sbp[0];
 716         int max_mnt_count = le16_to_cpu(sbp->s_max_mnt_count);
 717         int mnt_count = le16_to_cpu(sbp->s_mnt_count);
 718
 719         /* nilfs->sem must be locked by the caller. */
 720         if (!(nilfs->ns_mount_state & NILFS_VALID_FS)) {
 721                 printk(KERN_WARNING "NILFS warning: mounting unchecked fs\n");
 722         } else if (nilfs->ns_mount_state & NILFS_ERROR_FS) {
 723                 printk(KERN_WARNING
 724                        "NILFS warning: mounting fs with errors\n");
 725 #if 0
 726         } else if (max_mnt_count >= 0 && mnt_count >= max_mnt_count) {
 727                 printk(KERN_WARNING
 728                        "NILFS warning: maximal mount count reached\n");
 729 #endif
 730         }
 731         if (!max_mnt_count)
 732                 sbp->s_max_mnt_count = cpu_to_le16(NILFS_DFL_MAX_MNT_COUNT);
 733
 734         sbp->s_mnt_count = cpu_to_le16(mnt_count + 1);
 735         sbp->s_state = cpu_to_le16(le16_to_cpu(sbp->s_state) & ~NILFS_VALID_FS);
 736         sbp->s_mtime = cpu_to_le64(get_seconds());
 737         return nilfs_commit_super(sbi, 1);
 738 }
 739
 740 struct nilfs_super_block *nilfs_read_super_block(struct super_block *sb,
 741                                                  u64 pos, int blocksize,
 742                                                  struct buffer_head **pbh)
 743 {
 744         unsigned long long sb_index = pos;
 745         unsigned long offset;
 746
 747         offset = do_div(sb_index, blocksize);
 748         *pbh = sb_bread(sb, sb_index);
 749         if (!*pbh)
 750                 return NULL;
 751         return (struct nilfs_super_block *)((char *)(*pbh)->b_data + offset);
 752 }
 753
 754 int nilfs_store_magic_and_option(struct super_block *sb,
 755                                  struct nilfs_super_block *sbp,
 756                                  char *data)
 757 {
 758         struct nilfs_sb_info *sbi = NILFS_SB(sb);
 759
 760         sb->s_magic = le16_to_cpu(sbp->s_magic);
 761
 762         /* FS independent flags */
 763 #ifdef NILFS_ATIME_DISABLE
 764         sb->s_flags |= MS_NOATIME;
 765 #endif
 766
 767         nilfs_set_default_options(sbi, sbp);
 768
 769         sbi->s_resuid = le16_to_cpu(sbp->s_def_resuid);
 770         sbi->s_resgid = le16_to_cpu(sbp->s_def_resgid);
 771         sbi->s_interval = le32_to_cpu(sbp->s_c_interval);
 772         sbi->s_watermark = le32_to_cpu(sbp->s_c_block_max);
 773
 774         return !parse_options(data, sb) ? -EINVAL : 0 ;
 775 }
 776
 777 /**
 778  * nilfs_fill_super() - initialize a super block instance
 779  * @sb: super_block
 780  * @data: mount options
 781  * @silent: silent mode flag
 782  * @nilfs: the_nilfs struct
 783  *
 784  * This function is called exclusively by nilfs->ns_mount_mutex.
 785  * So, the recovery process is protected from other simultaneous mounts.
 786  */
 787 static int
 788 nilfs_fill_super(struct super_block *sb, void *data, int silent,
 789                  struct the_nilfs *nilfs)
 790 {
 791         struct nilfs_sb_info *sbi;
 792         struct inode *root;
 793         __u64 cno;
 794         int err;
 795
 796         sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
 797         if (!sbi)
 798                 return -ENOMEM;
 799
 800         sb->s_fs_info = sbi;
 801
 802         get_nilfs(nilfs);
 803         sbi->s_nilfs = nilfs;
 804         sbi->s_super = sb;
 805         atomic_set(&sbi->s_count, 1);
 806
 807         err = init_nilfs(nilfs, sbi, (char *)data);
 808         if (err)
 809                 goto failed_sbi;
 810
 811         spin_lock_init(&sbi->s_inode_lock);
 812         INIT_LIST_HEAD(&sbi->s_dirty_files);
 813         INIT_LIST_HEAD(&sbi->s_list);
 814
 815         /*
 816          * Following initialization is overlapped because
 817          * nilfs_sb_info structure has been cleared at the beginning.
 818          * But we reserve them to keep our interest and make ready
 819          * for the future change.
 820          */
 821         get_random_bytes(&sbi->s_next_generation,
 822                          sizeof(sbi->s_next_generation));
 823         spin_lock_init(&sbi->s_next_gen_lock);
 824
 825         sb->s_op = &nilfs_sops;
 826         sb->s_export_op = &nilfs_export_ops;
 827         sb->s_root = NULL;
 828         sb->s_time_gran = 1;
 829
 830         if (!nilfs_loaded(nilfs)) {
 831                 err = load_nilfs(nilfs, sbi);
 832                 if (err)
 833                         goto failed_sbi;
 834         }
 835         cno = nilfs_last_cno(nilfs);
 836
 837         if (sb->s_flags & MS_RDONLY) {
 838                 if (nilfs_test_opt(sbi, SNAPSHOT)) {
 839                         err = nilfs_cpfile_is_snapshot(nilfs->ns_cpfile,
 840                                                        sbi->s_snapshot_cno);
 841                         if (err < 0)
 842                                 goto failed_sbi;
 843                         if (!err) {
 844                                 printk(KERN_ERR
 845                                        "NILFS: The specified checkpoint is "
 846                                        "not a snapshot "
 847                                        "(checkpoint number=%llu).\n",
 848                                        (unsigned long long)sbi->s_snapshot_cno);
 849                                 err = -EINVAL;
 850                                 goto failed_sbi;
 851                         }
 852                         cno = sbi->s_snapshot_cno;
 853                 } else
 854                         /* Read-only mount */
 855                         sbi->s_snapshot_cno = cno;
 856         }
 857
 858         err = nilfs_attach_checkpoint(sbi, cno);
 859         if (err) {
 860                 printk(KERN_ERR "NILFS: error loading a checkpoint"
 861                        " (checkpoint number=%llu).\n", (unsigned long long)cno);
 862                 goto failed_sbi;
 863         }
 864
 865         if (!(sb->s_flags & MS_RDONLY)) {
 866                 err = nilfs_attach_segment_constructor(sbi);
 867                 if (err)
 868                         goto failed_checkpoint;
 869         }
 870
 871         root = nilfs_iget(sb, NILFS_ROOT_INO);
 872         if (IS_ERR(root)) {
 873                 printk(KERN_ERR "NILFS: get root inode failed\n");
 874                 err = PTR_ERR(root);
 875                 goto failed_segctor;
 876         }
 877         if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
 878                 iput(root);
 879                 printk(KERN_ERR "NILFS: corrupt root inode.\n");
 880                 err = -EINVAL;
 881                 goto failed_segctor;
 882         }
 883         sb->s_root = d_alloc_root(root);
 884         if (!sb->s_root) {
 885                 iput(root);
 886                 printk(KERN_ERR "NILFS: get root dentry failed\n");
 887                 err = -ENOMEM;
 888                 goto failed_segctor;
 889         }
 890
 891         if (!(sb->s_flags & MS_RDONLY)) {
 892                 down_write(&nilfs->ns_sem);
 893                 nilfs_setup_super(sbi);
 894                 up_write(&nilfs->ns_sem);
 895         }
 896
 897         err = nilfs_mark_recovery_complete(sbi);
 898         if (unlikely(err)) {
 899                 printk(KERN_ERR "NILFS: recovery failed.\n");
 900                 goto failed_root;
 901         }
 902
 903         down_write(&nilfs->ns_super_sem);
 904         if (!nilfs_test_opt(sbi, SNAPSHOT))
 905                 nilfs->ns_current = sbi;
 906         up_write(&nilfs->ns_super_sem);
 907
 908         return 0;
 909
 910  failed_root:
 911         dput(sb->s_root);
 912         sb->s_root = NULL;
 913
 914  failed_segctor:
 915         nilfs_detach_segment_constructor(sbi);
 916
 917  failed_checkpoint:
 918         nilfs_detach_checkpoint(sbi);
 919
 920  failed_sbi:
 921         put_nilfs(nilfs);
 922         sb->s_fs_info = NULL;
 923         nilfs_put_sbinfo(sbi);
 924         return err;
 925 }
 926
 927 static int nilfs_remount(struct super_block *sb, int *flags, char *data)
 928 {
 929         struct nilfs_sb_info *sbi = NILFS_SB(sb);
 930         struct nilfs_super_block *sbp;
 931         struct the_nilfs *nilfs = sbi->s_nilfs;
 932         unsigned long old_sb_flags;
 933         struct nilfs_mount_options old_opts;
 934         int err;
 935
 936         lock_kernel();
 937
 938         down_write(&nilfs->ns_super_sem);
 939         old_sb_flags = sb->s_flags;
 940         old_opts.mount_opt = sbi->s_mount_opt;
 941         old_opts.snapshot_cno = sbi->s_snapshot_cno;
 942
 943         if (!parse_options(data, sb)) {
 944                 err = -EINVAL;
 945                 goto restore_opts;
 946         }
 947         sb->s_flags = (sb->s_flags & ~MS_POSIXACL);
 948
 949         if ((*flags & MS_RDONLY) &&
 950             sbi->s_snapshot_cno != old_opts.snapshot_cno) {
 951                 printk(KERN_WARNING "NILFS (device %s): couldn't "
 952                        "remount to a different snapshot. \n",
 953                        sb->s_id);
 954                 err = -EINVAL;
 955                 goto restore_opts;
 956         }
 957
 958         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
 959                 goto out;
 960         if (*flags & MS_RDONLY) {
 961                 /* Shutting down the segment constructor */
 962                 nilfs_detach_segment_constructor(sbi);
 963                 sb->s_flags |= MS_RDONLY;
 964
 965                 sbi->s_snapshot_cno = nilfs_last_cno(nilfs);
 966                 /* nilfs_set_opt(sbi, SNAPSHOT); */
 967
 968                 /*
 969                  * Remounting a valid RW partition RDONLY, so set
 970                  * the RDONLY flag and then mark the partition as valid again.
 971                  */
 972                 down_write(&nilfs->ns_sem);
 973                 sbp = nilfs->ns_sbp[0];
 974                 if (!(sbp->s_state & le16_to_cpu(NILFS_VALID_FS)) &&
 975                     (nilfs->ns_mount_state & NILFS_VALID_FS))
 976                         sbp->s_state = cpu_to_le16(nilfs->ns_mount_state);
 977                 sbp->s_mtime = cpu_to_le64(get_seconds());
 978                 nilfs_commit_super(sbi, 1);
 979                 up_write(&nilfs->ns_sem);
 980         } else {
 981                 /*
 982                  * Mounting a RDONLY partition read-write, so reread and
 983                  * store the current valid flag.  (It may have been changed
 984                  * by fsck since we originally mounted the partition.)
 985                  */
 986                 if (nilfs->ns_current && nilfs->ns_current != sbi) {
 987                         printk(KERN_WARNING "NILFS (device %s): couldn't "
 988                                "remount because an RW-mount exists.\n",
 989                                sb->s_id);
 990                         err = -EBUSY;
 991                         goto restore_opts;
 992                 }
 993                 if (sbi->s_snapshot_cno != nilfs_last_cno(nilfs)) {
 994                         printk(KERN_WARNING "NILFS (device %s): couldn't "
 995                                "remount because the current RO-mount is not "
 996                                "the latest one.\n",
 997                                sb->s_id);
 998                         err = -EINVAL;
 999                         goto restore_opts;
1000                 }
1001                 sb->s_flags &= ~MS_RDONLY;
1002                 nilfs_clear_opt(sbi, SNAPSHOT);
1003                 sbi->s_snapshot_cno = 0;
1004
1005                 err = nilfs_attach_segment_constructor(sbi);
1006                 if (err)
1007                         goto restore_opts;
1008
1009                 down_write(&nilfs->ns_sem);
1010                 nilfs_setup_super(sbi);
1011                 up_write(&nilfs->ns_sem);
1012
1013                 nilfs->ns_current = sbi;
1014         }
1015  out:
1016         up_write(&nilfs->ns_super_sem);
1017         unlock_kernel();
1018         return 0;
1019
1020  restore_opts:
1021         sb->s_flags = old_sb_flags;
1022         sbi->s_mount_opt = old_opts.mount_opt;
1023         sbi->s_snapshot_cno = old_opts.snapshot_cno;
1024         up_write(&nilfs->ns_super_sem);
1025         unlock_kernel();
1026         return err;
1027 }
1028
1029 struct nilfs_super_data {
1030         struct block_device *bdev;
1031         struct nilfs_sb_info *sbi;
1032         __u64 cno;
1033         int flags;
1034 };
1035
1036 /**
1037  * nilfs_identify - pre-read mount options needed to identify mount instance
1038  * @data: mount options
1039  * @sd: nilfs_super_data
1040  */
1041 static int nilfs_identify(char *data, struct nilfs_super_data *sd)
1042 {
1043         char *p, *options = data;
1044         substring_t args[MAX_OPT_ARGS];
1045         int option, token;
1046         int ret = 0;
1047
1048         do {
1049                 p = strsep(&options, ",");
1050                 if (p != NULL && *p) {
1051                         token = match_token(p, tokens, args);
1052                         if (token == Opt_snapshot) {
1053                                 if (!(sd->flags & MS_RDONLY))
1054                                         ret++;
1055                                 else {
1056                                         ret = match_int(&args[0], &option);
1057                                         if (!ret) {
1058                                                 if (option > 0)
1059                                                         sd->cno = option;
1060                                                 else
1061                                                         ret++;
1062                                         }
1063                                 }
1064                         }
1065                         if (ret)
1066                                 printk(KERN_ERR
1067                                        "NILFS: invalid mount option: %s\n", p);
1068                 }
1069                 if (!options)
1070                         break;
1071                 BUG_ON(options == data);
1072                 *(options - 1) = ',';
1073         } while (!ret);
1074         return ret;
1075 }
1076
1077 static int nilfs_set_bdev_super(struct super_block *s, void *data)
1078 {
1079         struct nilfs_super_data *sd = data;
1080
1081         s->s_bdev = sd->bdev;
1082         s->s_dev = s->s_bdev->bd_dev;
1083         return 0;
1084 }
1085
1086 static int nilfs_test_bdev_super(struct super_block *s, void *data)
1087 {
1088         struct nilfs_super_data *sd = data;
1089
1090         return sd->sbi && s->s_fs_info == (void *)sd->sbi;
1091 }
1092
1093 static int
1094 nilfs_get_sb(struct file_system_type *fs_type, int flags,
1095              const char *dev_name, void *data, struct vfsmount *mnt)
1096 {
1097         struct nilfs_super_data sd;
1098         struct super_block *s;
1099         struct the_nilfs *nilfs;
1100         int err, need_to_close = 1;
1101
1102         sd.bdev = open_bdev_exclusive(dev_name, flags, fs_type);
1103         if (IS_ERR(sd.bdev))
1104                 return PTR_ERR(sd.bdev);
1105
1106         /*
1107          * To get mount instance using sget() vfs-routine, NILFS needs
1108          * much more information than normal filesystems to identify mount
1109          * instance.  For snapshot mounts, not only a mount type (ro-mount
1110          * or rw-mount) but also a checkpoint number is required.
1111          */
1112         sd.cno = 0;
1113         sd.flags = flags;
1114         if (nilfs_identify((char *)data, &sd)) {
1115                 err = -EINVAL;
1116                 goto failed;
1117         }
1118
1119         nilfs = find_or_create_nilfs(sd.bdev);
1120         if (!nilfs) {
1121                 err = -ENOMEM;
1122                 goto failed;
1123         }
1124
1125         mutex_lock(&nilfs->ns_mount_mutex);
1126
1127         if (!sd.cno) {
1128                 /*
1129                  * Check if an exclusive mount exists or not.
1130                  * Snapshot mounts coexist with a current mount
1131                  * (i.e. rw-mount or ro-mount), whereas rw-mount and
1132                  * ro-mount are mutually exclusive.
1133                  */
1134                 down_read(&nilfs->ns_super_sem);
1135                 if (nilfs->ns_current &&
1136                     ((nilfs->ns_current->s_super->s_flags ^ flags)
1137                      & MS_RDONLY)) {
1138                         up_read(&nilfs->ns_super_sem);
1139                         err = -EBUSY;
1140                         goto failed_unlock;
1141                 }
1142                 up_read(&nilfs->ns_super_sem);
1143         }
1144
1145         /*
1146          * Find existing nilfs_sb_info struct
1147          */
1148         sd.sbi = nilfs_find_sbinfo(nilfs, !(flags & MS_RDONLY), sd.cno);
1149
1150         if (!sd.cno)
1151                 /* trying to get the latest checkpoint.  */
1152                 sd.cno = nilfs_last_cno(nilfs);
1153
1154         /*
1155          * Get super block instance holding the nilfs_sb_info struct.
1156          * A new instance is allocated if no existing mount is present or
1157          * existing instance has been unmounted.
1158          */
1159         s = sget(fs_type, nilfs_test_bdev_super, nilfs_set_bdev_super, &sd);
1160         if (sd.sbi)
1161                 nilfs_put_sbinfo(sd.sbi);
1162
1163         if (IS_ERR(s)) {
1164                 err = PTR_ERR(s);
1165                 goto failed_unlock;
1166         }
1167
1168         if (!s->s_root) {
1169                 char b[BDEVNAME_SIZE];
1170
1171                 /* New superblock instance created */
1172                 s->s_flags = flags;
1173                 strlcpy(s->s_id, bdevname(sd.bdev, b), sizeof(s->s_id));
1174                 sb_set_blocksize(s, block_size(sd.bdev));
1175
1176                 err = nilfs_fill_super(s, data, flags & MS_VERBOSE, nilfs);
1177                 if (err)
1178                         goto cancel_new;
1179
1180                 s->s_flags |= MS_ACTIVE;
1181                 need_to_close = 0;
1182         }
1183
1184         mutex_unlock(&nilfs->ns_mount_mutex);
1185         put_nilfs(nilfs);
1186         if (need_to_close)
1187                 close_bdev_exclusive(sd.bdev, flags);
1188         simple_set_mnt(mnt, s);
1189         return 0;
1190
1191  failed_unlock:
1192         mutex_unlock(&nilfs->ns_mount_mutex);
1193         put_nilfs(nilfs);
1194  failed:
1195         close_bdev_exclusive(sd.bdev, flags);
1196
1197         return err;
1198
1199  cancel_new:
1200         /* Abandoning the newly allocated superblock */
1201         mutex_unlock(&nilfs->ns_mount_mutex);
1202         put_nilfs(nilfs);
1203         up_write(&s->s_umount);
1204         deactivate_super(s);
1205         /*
1206          * deactivate_super() invokes close_bdev_exclusive().
1207          * We must finish all post-cleaning before this call;
1208          * put_nilfs() needs the block device.
1209          */
1210         return err;
1211 }
1212
1213 struct file_system_type nilfs_fs_type = {
1214         .owner    = THIS_MODULE,
1215         .name     = "nilfs2",
1216         .get_sb   = nilfs_get_sb,
1217         .kill_sb  = kill_block_super,
1218         .fs_flags = FS_REQUIRES_DEV,
1219 };
1220
1221 static int __init init_nilfs_fs(void)
1222 {
1223         int err;
1224
1225         err = nilfs_init_inode_cache();
1226         if (err)
1227                 goto failed;
1228
1229         err = nilfs_init_transaction_cache();
1230         if (err)
1231                 goto failed_inode_cache;
1232
1233         err = nilfs_init_segbuf_cache();
1234         if (err)
1235                 goto failed_transaction_cache;
1236
1237         err = nilfs_btree_path_cache_init();
1238         if (err)
1239                 goto failed_segbuf_cache;
1240
1241         err = register_filesystem(&nilfs_fs_type);
1242         if (err)
1243                 goto failed_btree_path_cache;
1244
1245         return 0;
1246
1247  failed_btree_path_cache:
1248         nilfs_btree_path_cache_destroy();
1249
1250  failed_segbuf_cache:
1251         nilfs_destroy_segbuf_cache();
1252
1253  failed_transaction_cache:
1254         nilfs_destroy_transaction_cache();
1255
1256  failed_inode_cache:
1257         nilfs_destroy_inode_cache();
1258
1259  failed:
1260         return err;
1261 }
1262
1263 static void __exit exit_nilfs_fs(void)
1264 {
1265         nilfs_destroy_segbuf_cache();
1266         nilfs_destroy_transaction_cache();
1267         nilfs_destroy_inode_cache();
1268         nilfs_btree_path_cache_destroy();
1269         unregister_filesystem(&nilfs_fs_type);
1270 }
1271
1272 module_init(init_nilfs_fs)
1273 module_exit(exit_nilfs_fs)