fs/nilfs2/super.c

   1 /*
   2  * super.c - NILFS module and super block management.
   3  *
   4  * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  19  *
  20  * Written by Ryusuke Konishi <ryusuke@osrg.net>
  21  */
  22 /*
  23  *  linux/fs/ext2/super.c
  24  *
  25  * Copyright (C) 1992, 1993, 1994, 1995
  26  * Remy Card (card@masi.ibp.fr)
  27  * Laboratoire MASI - Institut Blaise Pascal
  28  * Universite Pierre et Marie Curie (Paris VI)
  29  *
  30  *  from
  31  *
  32  *  linux/fs/minix/inode.c
  33  *
  34  *  Copyright (C) 1991, 1992  Linus Torvalds
  35  *
  36  *  Big-endian to little-endian byte-swapping/bitmaps by
  37  *        David S. Miller (davem@caip.rutgers.edu), 1995
  38  */
  39
  40 #include <linux/module.h>
  41 #include <linux/string.h>
  42 #include <linux/slab.h>
  43 #include <linux/init.h>
  44 #include <linux/blkdev.h>
  45 #include <linux/parser.h>
  46 #include <linux/random.h>
  47 #include <linux/crc32.h>
  48 #include <linux/vfs.h>
  49 #include <linux/writeback.h>
  50 #include <linux/kobject.h>
  51 #include <linux/seq_file.h>
  52 #include <linux/mount.h>
  53 #include "nilfs.h"
  54 #include "export.h"
  55 #include "mdt.h"
  56 #include "alloc.h"
  57 #include "btree.h"
  58 #include "btnode.h"
  59 #include "page.h"
  60 #include "cpfile.h"
  61 #include "ifile.h"
  62 #include "dat.h"
  63 #include "segment.h"
  64 #include "segbuf.h"
  65
  66 MODULE_AUTHOR("NTT Corp.");
  67 MODULE_DESCRIPTION("A New Implementation of the Log-structured Filesystem "
  68                    "(NILFS)");
  69 MODULE_LICENSE("GPL");
  70
  71 struct kmem_cache *nilfs_inode_cachep;
  72 struct kmem_cache *nilfs_transaction_cachep;
  73 struct kmem_cache *nilfs_segbuf_cachep;
  74 struct kmem_cache *nilfs_btree_path_cache;
  75
  76 static int nilfs_setup_super(struct nilfs_sb_info *sbi, int is_mount);
  77 static int nilfs_remount(struct super_block *sb, int *flags, char *data);
  78
  79 static void nilfs_set_error(struct nilfs_sb_info *sbi)
  80 {
  81         struct the_nilfs *nilfs = sbi->s_nilfs;
  82         struct nilfs_super_block **sbp;
  83
  84         down_write(&nilfs->ns_sem);
  85         if (!(nilfs->ns_mount_state & NILFS_ERROR_FS)) {
  86                 nilfs->ns_mount_state |= NILFS_ERROR_FS;
  87                 sbp = nilfs_prepare_super(sbi, 0);
  88                 if (likely(sbp)) {
  89                         sbp[0]->s_state |= cpu_to_le16(NILFS_ERROR_FS);
  90                         if (sbp[1])
  91                                 sbp[1]->s_state |= cpu_to_le16(NILFS_ERROR_FS);
  92                         nilfs_commit_super(sbi, NILFS_SB_COMMIT_ALL);
  93                 }
  94         }
  95         up_write(&nilfs->ns_sem);
  96 }
  97
  98 /**
  99  * nilfs_error() - report failure condition on a filesystem
 100  *
 101  * nilfs_error() sets an ERROR_FS flag on the superblock as well as
 102  * reporting an error message.  It should be called when NILFS detects
 103  * incoherences or defects of meta data on disk.  As for sustainable
 104  * errors such as a single-shot I/O error, nilfs_warning() or the printk()
 105  * function should be used instead.
 106  *
 107  * The segment constructor must not call this function because it can
 108  * kill itself.
 109  */
 110 void nilfs_error(struct super_block *sb, const char *function,
 111                  const char *fmt, ...)
 112 {
 113         struct nilfs_sb_info *sbi = NILFS_SB(sb);
 114         va_list args;
 115
 116         va_start(args, fmt);
 117         printk(KERN_CRIT "NILFS error (device %s): %s: ", sb->s_id, function);
 118         vprintk(fmt, args);
 119         printk("\n");
 120         va_end(args);
 121
 122         if (!(sb->s_flags & MS_RDONLY)) {
 123                 nilfs_set_error(sbi);
 124
 125                 if (nilfs_test_opt(sbi, ERRORS_RO)) {
 126                         printk(KERN_CRIT "Remounting filesystem read-only\n");
 127                         sb->s_flags |= MS_RDONLY;
 128                 }
 129         }
 130
 131         if (nilfs_test_opt(sbi, ERRORS_PANIC))
 132                 panic("NILFS (device %s): panic forced after error\n",
 133                       sb->s_id);
 134 }
 135
 136 void nilfs_warning(struct super_block *sb, const char *function,
 137                    const char *fmt, ...)
 138 {
 139         va_list args;
 140
 141         va_start(args, fmt);
 142         printk(KERN_WARNING "NILFS warning (device %s): %s: ",
 143                sb->s_id, function);
 144         vprintk(fmt, args);
 145         printk("\n");
 146         va_end(args);
 147 }
 148
 149
 150 struct inode *nilfs_alloc_inode(struct super_block *sb)
 151 {
 152         struct nilfs_inode_info *ii;
 153
 154         ii = kmem_cache_alloc(nilfs_inode_cachep, GFP_NOFS);
 155         if (!ii)
 156                 return NULL;
 157         ii->i_bh = NULL;
 158         ii->i_state = 0;
 159         ii->i_cno = 0;
 160         ii->vfs_inode.i_version = 1;
 161         nilfs_btnode_cache_init(&ii->i_btnode_cache, sb->s_bdi);
 162         return &ii->vfs_inode;
 163 }
 164
 165 void nilfs_destroy_inode(struct inode *inode)
 166 {
 167         struct nilfs_mdt_info *mdi = NILFS_MDT(inode);
 168
 169         if (mdi) {
 170                 kfree(mdi->mi_bgl); /* kfree(NULL) is safe */
 171                 kfree(mdi);
 172         }
 173         kmem_cache_free(nilfs_inode_cachep, NILFS_I(inode));
 174 }
 175
 176 static int nilfs_sync_super(struct nilfs_sb_info *sbi, int flag)
 177 {
 178         struct the_nilfs *nilfs = sbi->s_nilfs;
 179         int err;
 180
 181  retry:
 182         set_buffer_dirty(nilfs->ns_sbh[0]);
 183
 184         if (nilfs_test_opt(sbi, BARRIER)) {
 185                 err = __sync_dirty_buffer(nilfs->ns_sbh[0],
 186                                           WRITE_SYNC | WRITE_BARRIER);
 187                 if (err == -EOPNOTSUPP) {
 188                         nilfs_warning(sbi->s_super, __func__,
 189                                       "barrier-based sync failed. "
 190                                       "disabling barriers\n");
 191                         nilfs_clear_opt(sbi, BARRIER);
 192                         goto retry;
 193                 }
 194         } else {
 195                 err = sync_dirty_buffer(nilfs->ns_sbh[0]);
 196         }
 197
 198         if (unlikely(err)) {
 199                 printk(KERN_ERR
 200                        "NILFS: unable to write superblock (err=%d)\n", err);
 201                 if (err == -EIO && nilfs->ns_sbh[1]) {
 202                         /*
 203                          * sbp[0] points to newer log than sbp[1],
 204                          * so copy sbp[0] to sbp[1] to take over sbp[0].
 205                          */
 206                         memcpy(nilfs->ns_sbp[1], nilfs->ns_sbp[0],
 207                                nilfs->ns_sbsize);
 208                         nilfs_fall_back_super_block(nilfs);
 209                         goto retry;
 210                 }
 211         } else {
 212                 struct nilfs_super_block *sbp = nilfs->ns_sbp[0];
 213
 214                 nilfs->ns_sbwcount++;
 215
 216                 /*
 217                  * The latest segment becomes trailable from the position
 218                  * written in superblock.
 219                  */
 220                 clear_nilfs_discontinued(nilfs);
 221
 222                 /* update GC protection for recent segments */
 223                 if (nilfs->ns_sbh[1]) {
 224                         if (flag == NILFS_SB_COMMIT_ALL) {
 225                                 set_buffer_dirty(nilfs->ns_sbh[1]);
 226                                 if (sync_dirty_buffer(nilfs->ns_sbh[1]) < 0)
 227                                         goto out;
 228                         }
 229                         if (le64_to_cpu(nilfs->ns_sbp[1]->s_last_cno) <
 230                             le64_to_cpu(nilfs->ns_sbp[0]->s_last_cno))
 231                                 sbp = nilfs->ns_sbp[1];
 232                 }
 233
 234                 spin_lock(&nilfs->ns_last_segment_lock);
 235                 nilfs->ns_prot_seq = le64_to_cpu(sbp->s_last_seq);
 236                 spin_unlock(&nilfs->ns_last_segment_lock);
 237         }
 238  out:
 239         return err;
 240 }
 241
 242 void nilfs_set_log_cursor(struct nilfs_super_block *sbp,
 243                           struct the_nilfs *nilfs)
 244 {
 245         sector_t nfreeblocks;
 246
 247         /* nilfs->ns_sem must be locked by the caller. */
 248         nilfs_count_free_blocks(nilfs, &nfreeblocks);
 249         sbp->s_free_blocks_count = cpu_to_le64(nfreeblocks);
 250
 251         spin_lock(&nilfs->ns_last_segment_lock);
 252         sbp->s_last_seq = cpu_to_le64(nilfs->ns_last_seq);
 253         sbp->s_last_pseg = cpu_to_le64(nilfs->ns_last_pseg);
 254         sbp->s_last_cno = cpu_to_le64(nilfs->ns_last_cno);
 255         spin_unlock(&nilfs->ns_last_segment_lock);
 256 }
 257
 258 struct nilfs_super_block **nilfs_prepare_super(struct nilfs_sb_info *sbi,
 259                                                int flip)
 260 {
 261         struct the_nilfs *nilfs = sbi->s_nilfs;
 262         struct nilfs_super_block **sbp = nilfs->ns_sbp;
 263
 264         /* nilfs->ns_sem must be locked by the caller. */
 265         if (sbp[0]->s_magic != cpu_to_le16(NILFS_SUPER_MAGIC)) {
 266                 if (sbp[1] &&
 267                     sbp[1]->s_magic == cpu_to_le16(NILFS_SUPER_MAGIC)) {
 268                         memcpy(sbp[0], sbp[1], nilfs->ns_sbsize);
 269                 } else {
 270                         printk(KERN_CRIT "NILFS: superblock broke on dev %s\n",
 271                                sbi->s_super->s_id);
 272                         return NULL;
 273                 }
 274         } else if (sbp[1] &&
 275                    sbp[1]->s_magic != cpu_to_le16(NILFS_SUPER_MAGIC)) {
 276                         memcpy(sbp[1], sbp[0], nilfs->ns_sbsize);
 277         }
 278
 279         if (flip && sbp[1])
 280                 nilfs_swap_super_block(nilfs);
 281
 282         return sbp;
 283 }
 284
 285 int nilfs_commit_super(struct nilfs_sb_info *sbi, int flag)
 286 {
 287         struct the_nilfs *nilfs = sbi->s_nilfs;
 288         struct nilfs_super_block **sbp = nilfs->ns_sbp;
 289         time_t t;
 290
 291         /* nilfs->ns_sem must be locked by the caller. */
 292         t = get_seconds();
 293         nilfs->ns_sbwtime = t;
 294         sbp[0]->s_wtime = cpu_to_le64(t);
 295         sbp[0]->s_sum = 0;
 296         sbp[0]->s_sum = cpu_to_le32(crc32_le(nilfs->ns_crc_seed,
 297                                              (unsigned char *)sbp[0],
 298                                              nilfs->ns_sbsize));
 299         if (flag == NILFS_SB_COMMIT_ALL && sbp[1]) {
 300                 sbp[1]->s_wtime = sbp[0]->s_wtime;
 301                 sbp[1]->s_sum = 0;
 302                 sbp[1]->s_sum = cpu_to_le32(crc32_le(nilfs->ns_crc_seed,
 303                                             (unsigned char *)sbp[1],
 304                                             nilfs->ns_sbsize));
 305         }
 306         clear_nilfs_sb_dirty(nilfs);
 307         return nilfs_sync_super(sbi, flag);
 308 }
 309
 310 /**
 311  * nilfs_cleanup_super() - write filesystem state for cleanup
 312  * @sbi: nilfs_sb_info to be unmounted or degraded to read-only
 313  *
 314  * This function restores state flags in the on-disk super block.
 315  * This will set "clean" flag (i.e. NILFS_VALID_FS) unless the
 316  * filesystem was not clean previously.
 317  */
 318 int nilfs_cleanup_super(struct nilfs_sb_info *sbi)
 319 {
 320         struct nilfs_super_block **sbp;
 321         int flag = NILFS_SB_COMMIT;
 322         int ret = -EIO;
 323
 324         sbp = nilfs_prepare_super(sbi, 0);
 325         if (sbp) {
 326                 sbp[0]->s_state = cpu_to_le16(sbi->s_nilfs->ns_mount_state);
 327                 nilfs_set_log_cursor(sbp[0], sbi->s_nilfs);
 328                 if (sbp[1] && sbp[0]->s_last_cno == sbp[1]->s_last_cno) {
 329                         /*
 330                          * make the "clean" flag also to the opposite
 331                          * super block if both super blocks point to
 332                          * the same checkpoint.
 333                          */
 334                         sbp[1]->s_state = sbp[0]->s_state;
 335                         flag = NILFS_SB_COMMIT_ALL;
 336                 }
 337                 ret = nilfs_commit_super(sbi, flag);
 338         }
 339         return ret;
 340 }
 341
 342 static void nilfs_put_super(struct super_block *sb)
 343 {
 344         struct nilfs_sb_info *sbi = NILFS_SB(sb);
 345         struct the_nilfs *nilfs = sbi->s_nilfs;
 346
 347         nilfs_detach_segment_constructor(sbi);
 348
 349         if (!(sb->s_flags & MS_RDONLY)) {
 350                 down_write(&nilfs->ns_sem);
 351                 nilfs_cleanup_super(sbi);
 352                 up_write(&nilfs->ns_sem);
 353         }
 354
 355         iput(nilfs->ns_sufile);
 356         iput(nilfs->ns_cpfile);
 357         iput(nilfs->ns_dat);
 358
 359         destroy_nilfs(nilfs);
 360         sbi->s_super = NULL;
 361         sb->s_fs_info = NULL;
 362         kfree(sbi);
 363 }
 364
 365 static int nilfs_sync_fs(struct super_block *sb, int wait)
 366 {
 367         struct nilfs_sb_info *sbi = NILFS_SB(sb);
 368         struct the_nilfs *nilfs = sbi->s_nilfs;
 369         struct nilfs_super_block **sbp;
 370         int err = 0;
 371
 372         /* This function is called when super block should be written back */
 373         if (wait)
 374                 err = nilfs_construct_segment(sb);
 375
 376         down_write(&nilfs->ns_sem);
 377         if (nilfs_sb_dirty(nilfs)) {
 378                 sbp = nilfs_prepare_super(sbi, nilfs_sb_will_flip(nilfs));
 379                 if (likely(sbp)) {
 380                         nilfs_set_log_cursor(sbp[0], nilfs);
 381                         nilfs_commit_super(sbi, NILFS_SB_COMMIT);
 382                 }
 383         }
 384         up_write(&nilfs->ns_sem);
 385
 386         return err;
 387 }
 388
 389 int nilfs_attach_checkpoint(struct nilfs_sb_info *sbi, __u64 cno, int curr_mnt,
 390                             struct nilfs_root **rootp)
 391 {
 392         struct the_nilfs *nilfs = sbi->s_nilfs;
 393         struct nilfs_root *root;
 394         struct nilfs_checkpoint *raw_cp;
 395         struct buffer_head *bh_cp;
 396         int err = -ENOMEM;
 397
 398         root = nilfs_find_or_create_root(
 399                 nilfs, curr_mnt ? NILFS_CPTREE_CURRENT_CNO : cno);
 400         if (!root)
 401                 return err;
 402
 403         if (root->ifile)
 404                 goto reuse; /* already attached checkpoint */
 405
 406         down_read(&nilfs->ns_segctor_sem);
 407         err = nilfs_cpfile_get_checkpoint(nilfs->ns_cpfile, cno, 0, &raw_cp,
 408                                           &bh_cp);
 409         up_read(&nilfs->ns_segctor_sem);
 410         if (unlikely(err)) {
 411                 if (err == -ENOENT || err == -EINVAL) {
 412                         printk(KERN_ERR
 413                                "NILFS: Invalid checkpoint "
 414                                "(checkpoint number=%llu)\n",
 415                                (unsigned long long)cno);
 416                         err = -EINVAL;
 417                 }
 418                 goto failed;
 419         }
 420
 421         err = nilfs_ifile_read(sbi->s_super, root, nilfs->ns_inode_size,
 422                                &raw_cp->cp_ifile_inode, &root->ifile);
 423         if (err)
 424                 goto failed_bh;
 425
 426         atomic_set(&root->inodes_count, le64_to_cpu(raw_cp->cp_inodes_count));
 427         atomic_set(&root->blocks_count, le64_to_cpu(raw_cp->cp_blocks_count));
 428
 429         nilfs_cpfile_put_checkpoint(nilfs->ns_cpfile, cno, bh_cp);
 430
 431  reuse:
 432         *rootp = root;
 433         return 0;
 434
 435  failed_bh:
 436         nilfs_cpfile_put_checkpoint(nilfs->ns_cpfile, cno, bh_cp);
 437  failed:
 438         nilfs_put_root(root);
 439
 440         return err;
 441 }
 442
 443 static int nilfs_freeze(struct super_block *sb)
 444 {
 445         struct nilfs_sb_info *sbi = NILFS_SB(sb);
 446         struct the_nilfs *nilfs = sbi->s_nilfs;
 447         int err;
 448
 449         if (sb->s_flags & MS_RDONLY)
 450                 return 0;
 451
 452         /* Mark super block clean */
 453         down_write(&nilfs->ns_sem);
 454         err = nilfs_cleanup_super(sbi);
 455         up_write(&nilfs->ns_sem);
 456         return err;
 457 }
 458
 459 static int nilfs_unfreeze(struct super_block *sb)
 460 {
 461         struct nilfs_sb_info *sbi = NILFS_SB(sb);
 462         struct the_nilfs *nilfs = sbi->s_nilfs;
 463
 464         if (sb->s_flags & MS_RDONLY)
 465                 return 0;
 466
 467         down_write(&nilfs->ns_sem);
 468         nilfs_setup_super(sbi, false);
 469         up_write(&nilfs->ns_sem);
 470         return 0;
 471 }
 472
 473 static int nilfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 474 {
 475         struct super_block *sb = dentry->d_sb;
 476         struct nilfs_root *root = NILFS_I(dentry->d_inode)->i_root;
 477         struct the_nilfs *nilfs = root->nilfs;
 478         u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
 479         unsigned long long blocks;
 480         unsigned long overhead;
 481         unsigned long nrsvblocks;
 482         sector_t nfreeblocks;
 483         int err;
 484
 485         /*
 486          * Compute all of the segment blocks
 487          *
 488          * The blocks before first segment and after last segment
 489          * are excluded.
 490          */
 491         blocks = nilfs->ns_blocks_per_segment * nilfs->ns_nsegments
 492                 - nilfs->ns_first_data_block;
 493         nrsvblocks = nilfs->ns_nrsvsegs * nilfs->ns_blocks_per_segment;
 494
 495         /*
 496          * Compute the overhead
 497          *
 498          * When distributing meta data blocks outside segment structure,
 499          * We must count them as the overhead.
 500          */
 501         overhead = 0;
 502
 503         err = nilfs_count_free_blocks(nilfs, &nfreeblocks);
 504         if (unlikely(err))
 505                 return err;
 506
 507         buf->f_type = NILFS_SUPER_MAGIC;
 508         buf->f_bsize = sb->s_blocksize;
 509         buf->f_blocks = blocks - overhead;
 510         buf->f_bfree = nfreeblocks;
 511         buf->f_bavail = (buf->f_bfree >= nrsvblocks) ?
 512                 (buf->f_bfree - nrsvblocks) : 0;
 513         buf->f_files = atomic_read(&root->inodes_count);
 514         buf->f_ffree = 0; /* nilfs_count_free_inodes(sb); */
 515         buf->f_namelen = NILFS_NAME_LEN;
 516         buf->f_fsid.val[0] = (u32)id;
 517         buf->f_fsid.val[1] = (u32)(id >> 32);
 518
 519         return 0;
 520 }
 521
 522 static int nilfs_show_options(struct seq_file *seq, struct vfsmount *vfs)
 523 {
 524         struct super_block *sb = vfs->mnt_sb;
 525         struct nilfs_sb_info *sbi = NILFS_SB(sb);
 526         struct nilfs_root *root = NILFS_I(vfs->mnt_root->d_inode)->i_root;
 527
 528         if (!nilfs_test_opt(sbi, BARRIER))
 529                 seq_puts(seq, ",nobarrier");
 530         if (root->cno != NILFS_CPTREE_CURRENT_CNO)
 531                 seq_printf(seq, ",cp=%llu", (unsigned long long)root->cno);
 532         if (nilfs_test_opt(sbi, ERRORS_PANIC))
 533                 seq_puts(seq, ",errors=panic");
 534         if (nilfs_test_opt(sbi, ERRORS_CONT))
 535                 seq_puts(seq, ",errors=continue");
 536         if (nilfs_test_opt(sbi, STRICT_ORDER))
 537                 seq_puts(seq, ",order=strict");
 538         if (nilfs_test_opt(sbi, NORECOVERY))
 539                 seq_puts(seq, ",norecovery");
 540         if (nilfs_test_opt(sbi, DISCARD))
 541                 seq_puts(seq, ",discard");
 542
 543         return 0;
 544 }
 545
 546 static const struct super_operations nilfs_sops = {
 547         .alloc_inode    = nilfs_alloc_inode,
 548         .destroy_inode  = nilfs_destroy_inode,
 549         .dirty_inode    = nilfs_dirty_inode,
 550         /* .write_inode    = nilfs_write_inode, */
 551         /* .put_inode      = nilfs_put_inode, */
 552         /* .drop_inode    = nilfs_drop_inode, */
 553         .evict_inode    = nilfs_evict_inode,
 554         .put_super      = nilfs_put_super,
 555         /* .write_super    = nilfs_write_super, */
 556         .sync_fs        = nilfs_sync_fs,
 557         .freeze_fs      = nilfs_freeze,
 558         .unfreeze_fs    = nilfs_unfreeze,
 559         /* .write_super_lockfs */
 560         /* .unlockfs */
 561         .statfs         = nilfs_statfs,
 562         .remount_fs     = nilfs_remount,
 563         /* .umount_begin */
 564         .show_options = nilfs_show_options
 565 };
 566
 567 enum {
 568         Opt_err_cont, Opt_err_panic, Opt_err_ro,
 569         Opt_barrier, Opt_nobarrier, Opt_snapshot, Opt_order, Opt_norecovery,
 570         Opt_discard, Opt_nodiscard, Opt_err,
 571 };
 572
 573 static match_table_t tokens = {
 574         {Opt_err_cont, "errors=continue"},
 575         {Opt_err_panic, "errors=panic"},
 576         {Opt_err_ro, "errors=remount-ro"},
 577         {Opt_barrier, "barrier"},
 578         {Opt_nobarrier, "nobarrier"},
 579         {Opt_snapshot, "cp=%u"},
 580         {Opt_order, "order=%s"},
 581         {Opt_norecovery, "norecovery"},
 582         {Opt_discard, "discard"},
 583         {Opt_nodiscard, "nodiscard"},
 584         {Opt_err, NULL}
 585 };
 586
 587 static int parse_options(char *options, struct super_block *sb, int is_remount)
 588 {
 589         struct nilfs_sb_info *sbi = NILFS_SB(sb);
 590         char *p;
 591         substring_t args[MAX_OPT_ARGS];
 592
 593         if (!options)
 594                 return 1;
 595
 596         while ((p = strsep(&options, ",")) != NULL) {
 597                 int token;
 598                 if (!*p)
 599                         continue;
 600
 601                 token = match_token(p, tokens, args);
 602                 switch (token) {
 603                 case Opt_barrier:
 604                         nilfs_set_opt(sbi, BARRIER);
 605                         break;
 606                 case Opt_nobarrier:
 607                         nilfs_clear_opt(sbi, BARRIER);
 608                         break;
 609                 case Opt_order:
 610                         if (strcmp(args[0].from, "relaxed") == 0)
 611                                 /* Ordered data semantics */
 612                                 nilfs_clear_opt(sbi, STRICT_ORDER);
 613                         else if (strcmp(args[0].from, "strict") == 0)
 614                                 /* Strict in-order semantics */
 615                                 nilfs_set_opt(sbi, STRICT_ORDER);
 616                         else
 617                                 return 0;
 618                         break;
 619                 case Opt_err_panic:
 620                         nilfs_write_opt(sbi, ERROR_MODE, ERRORS_PANIC);
 621                         break;
 622                 case Opt_err_ro:
 623                         nilfs_write_opt(sbi, ERROR_MODE, ERRORS_RO);
 624                         break;
 625                 case Opt_err_cont:
 626                         nilfs_write_opt(sbi, ERROR_MODE, ERRORS_CONT);
 627                         break;
 628                 case Opt_snapshot:
 629                         if (is_remount) {
 630                                 printk(KERN_ERR
 631                                        "NILFS: \"%s\" option is invalid "
 632                                        "for remount.\n", p);
 633                                 return 0;
 634                         }
 635                         break;
 636                 case Opt_norecovery:
 637                         nilfs_set_opt(sbi, NORECOVERY);
 638                         break;
 639                 case Opt_discard:
 640                         nilfs_set_opt(sbi, DISCARD);
 641                         break;
 642                 case Opt_nodiscard:
 643                         nilfs_clear_opt(sbi, DISCARD);
 644                         break;
 645                 default:
 646                         printk(KERN_ERR
 647                                "NILFS: Unrecognized mount option \"%s\"\n", p);
 648                         return 0;
 649                 }
 650         }
 651         return 1;
 652 }
 653
 654 static inline void
 655 nilfs_set_default_options(struct nilfs_sb_info *sbi,
 656                           struct nilfs_super_block *sbp)
 657 {
 658         sbi->s_mount_opt =
 659                 NILFS_MOUNT_ERRORS_RO | NILFS_MOUNT_BARRIER;
 660 }
 661
 662 static int nilfs_setup_super(struct nilfs_sb_info *sbi, int is_mount)
 663 {
 664         struct the_nilfs *nilfs = sbi->s_nilfs;
 665         struct nilfs_super_block **sbp;
 666         int max_mnt_count;
 667         int mnt_count;
 668
 669         /* nilfs->ns_sem must be locked by the caller. */
 670         sbp = nilfs_prepare_super(sbi, 0);
 671         if (!sbp)
 672                 return -EIO;
 673
 674         if (!is_mount)
 675                 goto skip_mount_setup;
 676
 677         max_mnt_count = le16_to_cpu(sbp[0]->s_max_mnt_count);
 678         mnt_count = le16_to_cpu(sbp[0]->s_mnt_count);
 679
 680         if (nilfs->ns_mount_state & NILFS_ERROR_FS) {
 681                 printk(KERN_WARNING
 682                        "NILFS warning: mounting fs with errors\n");
 683 #if 0
 684         } else if (max_mnt_count >= 0 && mnt_count >= max_mnt_count) {
 685                 printk(KERN_WARNING
 686                        "NILFS warning: maximal mount count reached\n");
 687 #endif
 688         }
 689         if (!max_mnt_count)
 690                 sbp[0]->s_max_mnt_count = cpu_to_le16(NILFS_DFL_MAX_MNT_COUNT);
 691
 692         sbp[0]->s_mnt_count = cpu_to_le16(mnt_count + 1);
 693         sbp[0]->s_mtime = cpu_to_le64(get_seconds());
 694
 695 skip_mount_setup:
 696         sbp[0]->s_state =
 697                 cpu_to_le16(le16_to_cpu(sbp[0]->s_state) & ~NILFS_VALID_FS);
 698         /* synchronize sbp[1] with sbp[0] */
 699         memcpy(sbp[1], sbp[0], nilfs->ns_sbsize);
 700         return nilfs_commit_super(sbi, NILFS_SB_COMMIT_ALL);
 701 }
 702
 703 struct nilfs_super_block *nilfs_read_super_block(struct super_block *sb,
 704                                                  u64 pos, int blocksize,
 705                                                  struct buffer_head **pbh)
 706 {
 707         unsigned long long sb_index = pos;
 708         unsigned long offset;
 709
 710         offset = do_div(sb_index, blocksize);
 711         *pbh = sb_bread(sb, sb_index);
 712         if (!*pbh)
 713                 return NULL;
 714         return (struct nilfs_super_block *)((char *)(*pbh)->b_data + offset);
 715 }
 716
 717 int nilfs_store_magic_and_option(struct super_block *sb,
 718                                  struct nilfs_super_block *sbp,
 719                                  char *data)
 720 {
 721         struct nilfs_sb_info *sbi = NILFS_SB(sb);
 722
 723         sb->s_magic = le16_to_cpu(sbp->s_magic);
 724
 725         /* FS independent flags */
 726 #ifdef NILFS_ATIME_DISABLE
 727         sb->s_flags |= MS_NOATIME;
 728 #endif
 729
 730         nilfs_set_default_options(sbi, sbp);
 731
 732         sbi->s_resuid = le16_to_cpu(sbp->s_def_resuid);
 733         sbi->s_resgid = le16_to_cpu(sbp->s_def_resgid);
 734         sbi->s_interval = le32_to_cpu(sbp->s_c_interval);
 735         sbi->s_watermark = le32_to_cpu(sbp->s_c_block_max);
 736
 737         return !parse_options(data, sb, 0) ? -EINVAL : 0 ;
 738 }
 739
 740 int nilfs_check_feature_compatibility(struct super_block *sb,
 741                                       struct nilfs_super_block *sbp)
 742 {
 743         __u64 features;
 744
 745         features = le64_to_cpu(sbp->s_feature_incompat) &
 746                 ~NILFS_FEATURE_INCOMPAT_SUPP;
 747         if (features) {
 748                 printk(KERN_ERR "NILFS: couldn't mount because of unsupported "
 749                        "optional features (%llx)\n",
 750                        (unsigned long long)features);
 751                 return -EINVAL;
 752         }
 753         features = le64_to_cpu(sbp->s_feature_compat_ro) &
 754                 ~NILFS_FEATURE_COMPAT_RO_SUPP;
 755         if (!(sb->s_flags & MS_RDONLY) && features) {
 756                 printk(KERN_ERR "NILFS: couldn't mount RDWR because of "
 757                        "unsupported optional features (%llx)\n",
 758                        (unsigned long long)features);
 759                 return -EINVAL;
 760         }
 761         return 0;
 762 }
 763
 764 static int nilfs_get_root_dentry(struct super_block *sb,
 765                                  struct nilfs_root *root,
 766                                  struct dentry **root_dentry)
 767 {
 768         struct inode *inode;
 769         struct dentry *dentry;
 770         int ret = 0;
 771
 772         inode = nilfs_iget(sb, root, NILFS_ROOT_INO);
 773         if (IS_ERR(inode)) {
 774                 printk(KERN_ERR "NILFS: get root inode failed\n");
 775                 ret = PTR_ERR(inode);
 776                 goto out;
 777         }
 778         if (!S_ISDIR(inode->i_mode) || !inode->i_blocks || !inode->i_size) {
 779                 iput(inode);
 780                 printk(KERN_ERR "NILFS: corrupt root inode.\n");
 781                 ret = -EINVAL;
 782                 goto out;
 783         }
 784
 785         if (root->cno == NILFS_CPTREE_CURRENT_CNO) {
 786                 dentry = d_find_alias(inode);
 787                 if (!dentry) {
 788                         dentry = d_alloc_root(inode);
 789                         if (!dentry) {
 790                                 iput(inode);
 791                                 ret = -ENOMEM;
 792                                 goto failed_dentry;
 793                         }
 794                 } else {
 795                         iput(inode);
 796                 }
 797         } else {
 798                 dentry = d_obtain_alias(inode);
 799                 if (IS_ERR(dentry)) {
 800                         ret = PTR_ERR(dentry);
 801                         goto failed_dentry;
 802                 }
 803         }
 804         *root_dentry = dentry;
 805  out:
 806         return ret;
 807
 808  failed_dentry:
 809         printk(KERN_ERR "NILFS: get root dentry failed\n");
 810         goto out;
 811 }
 812
 813 static int nilfs_attach_snapshot(struct super_block *s, __u64 cno,
 814                                  struct dentry **root_dentry)
 815 {
 816         struct the_nilfs *nilfs = NILFS_SB(s)->s_nilfs;
 817         struct nilfs_root *root;
 818         int ret;
 819
 820         down_read(&nilfs->ns_segctor_sem);
 821         ret = nilfs_cpfile_is_snapshot(nilfs->ns_cpfile, cno);
 822         up_read(&nilfs->ns_segctor_sem);
 823         if (ret < 0) {
 824                 ret = (ret == -ENOENT) ? -EINVAL : ret;
 825                 goto out;
 826         } else if (!ret) {
 827                 printk(KERN_ERR "NILFS: The specified checkpoint is "
 828                        "not a snapshot (checkpoint number=%llu).\n",
 829                        (unsigned long long)cno);
 830                 ret = -EINVAL;
 831                 goto out;
 832         }
 833
 834         ret = nilfs_attach_checkpoint(NILFS_SB(s), cno, false, &root);
 835         if (ret) {
 836                 printk(KERN_ERR "NILFS: error loading snapshot "
 837                        "(checkpoint number=%llu).\n",
 838                (unsigned long long)cno);
 839                 goto out;
 840         }
 841         ret = nilfs_get_root_dentry(s, root, root_dentry);
 842         nilfs_put_root(root);
 843  out:
 844         return ret;
 845 }
 846
 847 static int nilfs_tree_was_touched(struct dentry *root_dentry)
 848 {
 849         return atomic_read(&root_dentry->d_count) > 1;
 850 }
 851
 852 /**
 853  * nilfs_try_to_shrink_tree() - try to shrink dentries of a checkpoint
 854  * @root_dentry: root dentry of the tree to be shrunk
 855  *
 856  * This function returns true if the tree was in-use.
 857  */
 858 static int nilfs_try_to_shrink_tree(struct dentry *root_dentry)
 859 {
 860         if (have_submounts(root_dentry))
 861                 return true;
 862         shrink_dcache_parent(root_dentry);
 863         return nilfs_tree_was_touched(root_dentry);
 864 }
 865
 866 int nilfs_checkpoint_is_mounted(struct super_block *sb, __u64 cno)
 867 {
 868         struct the_nilfs *nilfs = NILFS_SB(sb)->s_nilfs;
 869         struct nilfs_root *root;
 870         struct inode *inode;
 871         struct dentry *dentry;
 872         int ret;
 873
 874         if (cno < 0 || cno > nilfs->ns_cno)
 875                 return false;
 876
 877         if (cno >= nilfs_last_cno(nilfs))
 878                 return true;    /* protect recent checkpoints */
 879
 880         ret = false;
 881         root = nilfs_lookup_root(NILFS_SB(sb)->s_nilfs, cno);
 882         if (root) {
 883                 inode = nilfs_ilookup(sb, root, NILFS_ROOT_INO);
 884                 if (inode) {
 885                         dentry = d_find_alias(inode);
 886                         if (dentry) {
 887                                 if (nilfs_tree_was_touched(dentry))
 888                                         ret = nilfs_try_to_shrink_tree(dentry);
 889                                 dput(dentry);
 890                         }
 891                         iput(inode);
 892                 }
 893                 nilfs_put_root(root);
 894         }
 895         return ret;
 896 }
 897
 898 /**
 899  * nilfs_fill_super() - initialize a super block instance
 900  * @sb: super_block
 901  * @data: mount options
 902  * @silent: silent mode flag
 903  *
 904  * This function is called exclusively by nilfs->ns_mount_mutex.
 905  * So, the recovery process is protected from other simultaneous mounts.
 906  */
 907 static int
 908 nilfs_fill_super(struct super_block *sb, void *data, int silent)
 909 {
 910         struct the_nilfs *nilfs;
 911         struct nilfs_sb_info *sbi;
 912         struct nilfs_root *fsroot;
 913         __u64 cno;
 914         int err;
 915
 916         sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
 917         if (!sbi)
 918                 return -ENOMEM;
 919
 920         sb->s_fs_info = sbi;
 921         sbi->s_super = sb;
 922
 923         nilfs = alloc_nilfs(sb->s_bdev);
 924         if (!nilfs) {
 925                 err = -ENOMEM;
 926                 goto failed_sbi;
 927         }
 928         sbi->s_nilfs = nilfs;
 929
 930         err = init_nilfs(nilfs, sbi, (char *)data);
 931         if (err)
 932                 goto failed_nilfs;
 933
 934         spin_lock_init(&sbi->s_inode_lock);
 935         INIT_LIST_HEAD(&sbi->s_dirty_files);
 936
 937         /*
 938          * Following initialization is overlapped because
 939          * nilfs_sb_info structure has been cleared at the beginning.
 940          * But we reserve them to keep our interest and make ready
 941          * for the future change.
 942          */
 943         get_random_bytes(&sbi->s_next_generation,
 944                          sizeof(sbi->s_next_generation));
 945         spin_lock_init(&sbi->s_next_gen_lock);
 946
 947         sb->s_op = &nilfs_sops;
 948         sb->s_export_op = &nilfs_export_ops;
 949         sb->s_root = NULL;
 950         sb->s_time_gran = 1;
 951         sb->s_bdi = nilfs->ns_bdi;
 952
 953         err = load_nilfs(nilfs, sbi);
 954         if (err)
 955                 goto failed_nilfs;
 956
 957         cno = nilfs_last_cno(nilfs);
 958         err = nilfs_attach_checkpoint(sbi, cno, true, &fsroot);
 959         if (err) {
 960                 printk(KERN_ERR "NILFS: error loading last checkpoint "
 961                        "(checkpoint number=%llu).\n", (unsigned long long)cno);
 962                 goto failed_unload;
 963         }
 964
 965         if (!(sb->s_flags & MS_RDONLY)) {
 966                 err = nilfs_attach_segment_constructor(sbi, fsroot);
 967                 if (err)
 968                         goto failed_checkpoint;
 969         }
 970
 971         err = nilfs_get_root_dentry(sb, fsroot, &sb->s_root);
 972         if (err)
 973                 goto failed_segctor;
 974
 975         nilfs_put_root(fsroot);
 976
 977         if (!(sb->s_flags & MS_RDONLY)) {
 978                 down_write(&nilfs->ns_sem);
 979                 nilfs_setup_super(sbi, true);
 980                 up_write(&nilfs->ns_sem);
 981         }
 982
 983         return 0;
 984
 985  failed_segctor:
 986         nilfs_detach_segment_constructor(sbi);
 987
 988  failed_checkpoint:
 989         nilfs_put_root(fsroot);
 990
 991  failed_unload:
 992         iput(nilfs->ns_sufile);
 993         iput(nilfs->ns_cpfile);
 994         iput(nilfs->ns_dat);
 995
 996  failed_nilfs:
 997         destroy_nilfs(nilfs);
 998
 999  failed_sbi:
1000         sb->s_fs_info = NULL;
1001         kfree(sbi);
1002         return err;
1003 }
1004
1005 static int nilfs_remount(struct super_block *sb, int *flags, char *data)
1006 {
1007         struct nilfs_sb_info *sbi = NILFS_SB(sb);
1008         struct the_nilfs *nilfs = sbi->s_nilfs;
1009         unsigned long old_sb_flags;
1010         struct nilfs_mount_options old_opts;
1011         int err;
1012
1013         old_sb_flags = sb->s_flags;
1014         old_opts.mount_opt = sbi->s_mount_opt;
1015
1016         if (!parse_options(data, sb, 1)) {
1017                 err = -EINVAL;
1018                 goto restore_opts;
1019         }
1020         sb->s_flags = (sb->s_flags & ~MS_POSIXACL);
1021
1022         err = -EINVAL;
1023
1024         if (!nilfs_valid_fs(nilfs)) {
1025                 printk(KERN_WARNING "NILFS (device %s): couldn't "
1026                        "remount because the filesystem is in an "
1027                        "incomplete recovery state.\n", sb->s_id);
1028                 goto restore_opts;
1029         }
1030
1031         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
1032                 goto out;
1033         if (*flags & MS_RDONLY) {
1034                 /* Shutting down the segment constructor */
1035                 nilfs_detach_segment_constructor(sbi);
1036                 sb->s_flags |= MS_RDONLY;
1037
1038                 /*
1039                  * Remounting a valid RW partition RDONLY, so set
1040                  * the RDONLY flag and then mark the partition as valid again.
1041                  */
1042                 down_write(&nilfs->ns_sem);
1043                 nilfs_cleanup_super(sbi);
1044                 up_write(&nilfs->ns_sem);
1045         } else {
1046                 __u64 features;
1047                 struct nilfs_root *root;
1048
1049                 /*
1050                  * Mounting a RDONLY partition read-write, so reread and
1051                  * store the current valid flag.  (It may have been changed
1052                  * by fsck since we originally mounted the partition.)
1053                  */
1054                 down_read(&nilfs->ns_sem);
1055                 features = le64_to_cpu(nilfs->ns_sbp[0]->s_feature_compat_ro) &
1056                         ~NILFS_FEATURE_COMPAT_RO_SUPP;
1057                 up_read(&nilfs->ns_sem);
1058                 if (features) {
1059                         printk(KERN_WARNING "NILFS (device %s): couldn't "
1060                                "remount RDWR because of unsupported optional "
1061                                "features (%llx)\n",
1062                                sb->s_id, (unsigned long long)features);
1063                         err = -EROFS;
1064                         goto restore_opts;
1065                 }
1066
1067                 sb->s_flags &= ~MS_RDONLY;
1068
1069                 root = NILFS_I(sb->s_root->d_inode)->i_root;
1070                 err = nilfs_attach_segment_constructor(sbi, root);
1071                 if (err)
1072                         goto restore_opts;
1073
1074                 down_write(&nilfs->ns_sem);
1075                 nilfs_setup_super(sbi, true);
1076                 up_write(&nilfs->ns_sem);
1077         }
1078  out:
1079         return 0;
1080
1081  restore_opts:
1082         sb->s_flags = old_sb_flags;
1083         sbi->s_mount_opt = old_opts.mount_opt;
1084         return err;
1085 }
1086
1087 struct nilfs_super_data {
1088         struct block_device *bdev;
1089         struct nilfs_sb_info *sbi;
1090         __u64 cno;
1091         int flags;
1092 };
1093
1094 /**
1095  * nilfs_identify - pre-read mount options needed to identify mount instance
1096  * @data: mount options
1097  * @sd: nilfs_super_data
1098  */
1099 static int nilfs_identify(char *data, struct nilfs_super_data *sd)
1100 {
1101         char *p, *options = data;
1102         substring_t args[MAX_OPT_ARGS];
1103         int token;
1104         int ret = 0;
1105
1106         do {
1107                 p = strsep(&options, ",");
1108                 if (p != NULL && *p) {
1109                         token = match_token(p, tokens, args);
1110                         if (token == Opt_snapshot) {
1111                                 if (!(sd->flags & MS_RDONLY)) {
1112                                         ret++;
1113                                 } else {
1114                                         sd->cno = simple_strtoull(args[0].from,
1115                                                                   NULL, 0);
1116                                         /*
1117                                          * No need to see the end pointer;
1118                                          * match_token() has done syntax
1119                                          * checking.
1120                                          */
1121                                         if (sd->cno == 0)
1122                                                 ret++;
1123                                 }
1124                         }
1125                         if (ret)
1126                                 printk(KERN_ERR
1127                                        "NILFS: invalid mount option: %s\n", p);
1128                 }
1129                 if (!options)
1130                         break;
1131                 BUG_ON(options == data);
1132                 *(options - 1) = ',';
1133         } while (!ret);
1134         return ret;
1135 }
1136
1137 static int nilfs_set_bdev_super(struct super_block *s, void *data)
1138 {
1139         s->s_bdev = data;
1140         s->s_dev = s->s_bdev->bd_dev;
1141         return 0;
1142 }
1143
1144 static int nilfs_test_bdev_super(struct super_block *s, void *data)
1145 {
1146         return (void *)s->s_bdev == data;
1147 }
1148
1149 static int
1150 nilfs_get_sb(struct file_system_type *fs_type, int flags,
1151              const char *dev_name, void *data, struct vfsmount *mnt)
1152 {
1153         struct nilfs_super_data sd;
1154         struct super_block *s;
1155         fmode_t mode = FMODE_READ;
1156         struct dentry *root_dentry;
1157         int err, s_new = false;
1158
1159         if (!(flags & MS_RDONLY))
1160                 mode |= FMODE_WRITE;
1161
1162         sd.bdev = open_bdev_exclusive(dev_name, mode, fs_type);
1163         if (IS_ERR(sd.bdev))
1164                 return PTR_ERR(sd.bdev);
1165
1166         sd.cno = 0;
1167         sd.flags = flags;
1168         if (nilfs_identify((char *)data, &sd)) {
1169                 err = -EINVAL;
1170                 goto failed;
1171         }
1172
1173         /*
1174          * once the super is inserted into the list by sget, s_umount
1175          * will protect the lockfs code from trying to start a snapshot
1176          * while we are mounting
1177          */
1178         mutex_lock(&sd.bdev->bd_fsfreeze_mutex);
1179         if (sd.bdev->bd_fsfreeze_count > 0) {
1180                 mutex_unlock(&sd.bdev->bd_fsfreeze_mutex);
1181                 err = -EBUSY;
1182                 goto failed;
1183         }
1184         s = sget(fs_type, nilfs_test_bdev_super, nilfs_set_bdev_super, sd.bdev);
1185         mutex_unlock(&sd.bdev->bd_fsfreeze_mutex);
1186         if (IS_ERR(s)) {
1187                 err = PTR_ERR(s);
1188                 goto failed;
1189         }
1190
1191         if (!s->s_root) {
1192                 char b[BDEVNAME_SIZE];
1193
1194                 s_new = true;
1195
1196                 /* New superblock instance created */
1197                 s->s_flags = flags;
1198                 s->s_mode = mode;
1199                 strlcpy(s->s_id, bdevname(sd.bdev, b), sizeof(s->s_id));
1200                 sb_set_blocksize(s, block_size(sd.bdev));
1201
1202                 err = nilfs_fill_super(s, data, flags & MS_SILENT ? 1 : 0);
1203                 if (err)
1204                         goto failed_super;
1205
1206                 s->s_flags |= MS_ACTIVE;
1207         } else if (!sd.cno) {
1208                 int busy = false;
1209
1210                 if (nilfs_tree_was_touched(s->s_root)) {
1211                         busy = nilfs_try_to_shrink_tree(s->s_root);
1212                         if (busy && (flags ^ s->s_flags) & MS_RDONLY) {
1213                                 printk(KERN_ERR "NILFS: the device already "
1214                                        "has a %s mount.\n",
1215                                        (s->s_flags & MS_RDONLY) ?
1216                                        "read-only" : "read/write");
1217                                 err = -EBUSY;
1218                                 goto failed_super;
1219                         }
1220                 }
1221                 if (!busy) {
1222                         /*
1223                          * Try remount to setup mount states if the current
1224                          * tree is not mounted and only snapshots use this sb.
1225                          */
1226                         err = nilfs_remount(s, &flags, data);
1227                         if (err)
1228                                 goto failed_super;
1229                 }
1230         }
1231
1232         if (sd.cno) {
1233                 err = nilfs_attach_snapshot(s, sd.cno, &root_dentry);
1234                 if (err)
1235                         goto failed_super;
1236         } else {
1237                 root_dentry = dget(s->s_root);
1238         }
1239
1240         if (!s_new)
1241                 close_bdev_exclusive(sd.bdev, mode);
1242
1243         mnt->mnt_sb = s;
1244         mnt->mnt_root = root_dentry;
1245         return 0;
1246
1247  failed_super:
1248         deactivate_locked_super(s);
1249
1250  failed:
1251         if (!s_new)
1252                 close_bdev_exclusive(sd.bdev, mode);
1253         return err;
1254 }
1255
1256 struct file_system_type nilfs_fs_type = {
1257         .owner    = THIS_MODULE,
1258         .name     = "nilfs2",
1259         .get_sb   = nilfs_get_sb,
1260         .kill_sb  = kill_block_super,
1261         .fs_flags = FS_REQUIRES_DEV,
1262 };
1263
1264 static void nilfs_inode_init_once(void *obj)
1265 {
1266         struct nilfs_inode_info *ii = obj;
1267
1268         INIT_LIST_HEAD(&ii->i_dirty);
1269 #ifdef CONFIG_NILFS_XATTR
1270         init_rwsem(&ii->xattr_sem);
1271 #endif
1272         nilfs_btnode_cache_init_once(&ii->i_btnode_cache);
1273         ii->i_bmap = &ii->i_bmap_data;
1274         inode_init_once(&ii->vfs_inode);
1275 }
1276
1277 static void nilfs_segbuf_init_once(void *obj)
1278 {
1279         memset(obj, 0, sizeof(struct nilfs_segment_buffer));
1280 }
1281
1282 static void nilfs_destroy_cachep(void)
1283 {
1284         if (nilfs_inode_cachep)
1285                 kmem_cache_destroy(nilfs_inode_cachep);
1286         if (nilfs_transaction_cachep)
1287                 kmem_cache_destroy(nilfs_transaction_cachep);
1288         if (nilfs_segbuf_cachep)
1289                 kmem_cache_destroy(nilfs_segbuf_cachep);
1290         if (nilfs_btree_path_cache)
1291                 kmem_cache_destroy(nilfs_btree_path_cache);
1292 }
1293
1294 static int __init nilfs_init_cachep(void)
1295 {
1296         nilfs_inode_cachep = kmem_cache_create("nilfs2_inode_cache",
1297                         sizeof(struct nilfs_inode_info), 0,
1298                         SLAB_RECLAIM_ACCOUNT, nilfs_inode_init_once);
1299         if (!nilfs_inode_cachep)
1300                 goto fail;
1301
1302         nilfs_transaction_cachep = kmem_cache_create("nilfs2_transaction_cache",
1303                         sizeof(struct nilfs_transaction_info), 0,
1304                         SLAB_RECLAIM_ACCOUNT, NULL);
1305         if (!nilfs_transaction_cachep)
1306                 goto fail;
1307
1308         nilfs_segbuf_cachep = kmem_cache_create("nilfs2_segbuf_cache",
1309                         sizeof(struct nilfs_segment_buffer), 0,
1310                         SLAB_RECLAIM_ACCOUNT, nilfs_segbuf_init_once);
1311         if (!nilfs_segbuf_cachep)
1312                 goto fail;
1313
1314         nilfs_btree_path_cache = kmem_cache_create("nilfs2_btree_path_cache",
1315                         sizeof(struct nilfs_btree_path) * NILFS_BTREE_LEVEL_MAX,
1316                         0, 0, NULL);
1317         if (!nilfs_btree_path_cache)
1318                 goto fail;
1319
1320         return 0;
1321
1322 fail:
1323         nilfs_destroy_cachep();
1324         return -ENOMEM;
1325 }
1326
1327 static int __init init_nilfs_fs(void)
1328 {
1329         int err;
1330
1331         err = nilfs_init_cachep();
1332         if (err)
1333                 goto fail;
1334
1335         err = register_filesystem(&nilfs_fs_type);
1336         if (err)
1337                 goto free_cachep;
1338
1339         printk(KERN_INFO "NILFS version 2 loaded\n");
1340         return 0;
1341
1342 free_cachep:
1343         nilfs_destroy_cachep();
1344 fail:
1345         return err;
1346 }
1347
1348 static void __exit exit_nilfs_fs(void)
1349 {
1350         nilfs_destroy_cachep();
1351         unregister_filesystem(&nilfs_fs_type);
1352 }
1353
1354 module_init(init_nilfs_fs)
1355 module_exit(exit_nilfs_fs)