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/seq_file.h>
  51 #include <linux/mount.h>
  52 #include "nilfs.h"
  53 #include "export.h"
  54 #include "mdt.h"
  55 #include "alloc.h"
  56 #include "btree.h"
  57 #include "btnode.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 struct kmem_cache *nilfs_inode_cachep;
  71 struct kmem_cache *nilfs_transaction_cachep;
  72 struct kmem_cache *nilfs_segbuf_cachep;
  73 struct kmem_cache *nilfs_btree_path_cache;
  74
  75 static int nilfs_setup_super(struct nilfs_sb_info *sbi, int is_mount);
  76 static int nilfs_remount(struct super_block *sb, int *flags, char *data);
  77
  78 static void nilfs_set_error(struct nilfs_sb_info *sbi)
  79 {
  80         struct the_nilfs *nilfs = sbi->s_nilfs;
  81         struct nilfs_super_block **sbp;
  82
  83         down_write(&nilfs->ns_sem);
  84         if (!(nilfs->ns_mount_state & NILFS_ERROR_FS)) {
  85                 nilfs->ns_mount_state |= NILFS_ERROR_FS;
  86                 sbp = nilfs_prepare_super(sbi, 0);
  87                 if (likely(sbp)) {
  88                         sbp[0]->s_state |= cpu_to_le16(NILFS_ERROR_FS);
  89                         if (sbp[1])
  90                                 sbp[1]->s_state |= cpu_to_le16(NILFS_ERROR_FS);
  91                         nilfs_commit_super(sbi, NILFS_SB_COMMIT_ALL);
  92                 }
  93         }
  94         up_write(&nilfs->ns_sem);
  95 }
  96
  97 /**
  98  * nilfs_error() - report failure condition on a filesystem
  99  *
 100  * nilfs_error() sets an ERROR_FS flag on the superblock as well as
 101  * reporting an error message.  It should be called when NILFS detects
 102  * incoherences or defects of meta data on disk.  As for sustainable
 103  * errors such as a single-shot I/O error, nilfs_warning() or the printk()
 104  * function should be used instead.
 105  *
 106  * The segment constructor must not call this function because it can
 107  * kill itself.
 108  */
 109 void nilfs_error(struct super_block *sb, const char *function,
 110                  const char *fmt, ...)
 111 {
 112         struct nilfs_sb_info *sbi = NILFS_SB(sb);
 113         struct va_format vaf;
 114         va_list args;
 115
 116         va_start(args, fmt);
 117
 118         vaf.fmt = fmt;
 119         vaf.va = &args;
 120
 121         printk(KERN_CRIT "NILFS error (device %s): %s: %pV\n",
 122                sb->s_id, function, &vaf);
 123
 124         va_end(args);
 125
 126         if (!(sb->s_flags & MS_RDONLY)) {
 127                 nilfs_set_error(sbi);
 128
 129                 if (nilfs_test_opt(sbi, ERRORS_RO)) {
 130                         printk(KERN_CRIT "Remounting filesystem read-only\n");
 131                         sb->s_flags |= MS_RDONLY;
 132                 }
 133         }
 134
 135         if (nilfs_test_opt(sbi, ERRORS_PANIC))
 136                 panic("NILFS (device %s): panic forced after error\n",
 137                       sb->s_id);
 138 }
 139
 140 void nilfs_warning(struct super_block *sb, const char *function,
 141                    const char *fmt, ...)
 142 {
 143         struct va_format vaf;
 144         va_list args;
 145
 146         va_start(args, fmt);
 147
 148         vaf.fmt = fmt;
 149         vaf.va = &args;
 150
 151         printk(KERN_WARNING "NILFS warning (device %s): %s: %pV\n",
 152                sb->s_id, function, &vaf);
 153
 154         va_end(args);
 155 }
 156
 157
 158 struct inode *nilfs_alloc_inode(struct super_block *sb)
 159 {
 160         struct nilfs_inode_info *ii;
 161
 162         ii = kmem_cache_alloc(nilfs_inode_cachep, GFP_NOFS);
 163         if (!ii)
 164                 return NULL;
 165         ii->i_bh = NULL;
 166         ii->i_state = 0;
 167         ii->i_cno = 0;
 168         ii->vfs_inode.i_version = 1;
 169         nilfs_btnode_cache_init(&ii->i_btnode_cache, sb->s_bdi);
 170         return &ii->vfs_inode;
 171 }
 172
 173 static void nilfs_i_callback(struct rcu_head *head)
 174 {
 175         struct inode *inode = container_of(head, struct inode, i_rcu);
 176         struct nilfs_mdt_info *mdi = NILFS_MDT(inode);
 177
 178         INIT_LIST_HEAD(&inode->i_dentry);
 179
 180         if (mdi) {
 181                 kfree(mdi->mi_bgl); /* kfree(NULL) is safe */
 182                 kfree(mdi);
 183         }
 184         kmem_cache_free(nilfs_inode_cachep, NILFS_I(inode));
 185 }
 186
 187 void nilfs_destroy_inode(struct inode *inode)
 188 {
 189         call_rcu(&inode->i_rcu, nilfs_i_callback);
 190 }
 191
 192 static int nilfs_sync_super(struct nilfs_sb_info *sbi, int flag)
 193 {
 194         struct the_nilfs *nilfs = sbi->s_nilfs;
 195         int err;
 196
 197  retry:
 198         set_buffer_dirty(nilfs->ns_sbh[0]);
 199         if (nilfs_test_opt(sbi, BARRIER)) {
 200                 err = __sync_dirty_buffer(nilfs->ns_sbh[0],
 201                                           WRITE_SYNC | WRITE_FLUSH_FUA);
 202         } else {
 203                 err = sync_dirty_buffer(nilfs->ns_sbh[0]);
 204         }
 205
 206         if (unlikely(err)) {
 207                 printk(KERN_ERR
 208                        "NILFS: unable to write superblock (err=%d)\n", err);
 209                 if (err == -EIO && nilfs->ns_sbh[1]) {
 210                         /*
 211                          * sbp[0] points to newer log than sbp[1],
 212                          * so copy sbp[0] to sbp[1] to take over sbp[0].
 213                          */
 214                         memcpy(nilfs->ns_sbp[1], nilfs->ns_sbp[0],
 215                                nilfs->ns_sbsize);
 216                         nilfs_fall_back_super_block(nilfs);
 217                         goto retry;
 218                 }
 219         } else {
 220                 struct nilfs_super_block *sbp = nilfs->ns_sbp[0];
 221
 222                 nilfs->ns_sbwcount++;
 223
 224                 /*
 225                  * The latest segment becomes trailable from the position
 226                  * written in superblock.
 227                  */
 228                 clear_nilfs_discontinued(nilfs);
 229
 230                 /* update GC protection for recent segments */
 231                 if (nilfs->ns_sbh[1]) {
 232                         if (flag == NILFS_SB_COMMIT_ALL) {
 233                                 set_buffer_dirty(nilfs->ns_sbh[1]);
 234                                 if (sync_dirty_buffer(nilfs->ns_sbh[1]) < 0)
 235                                         goto out;
 236                         }
 237                         if (le64_to_cpu(nilfs->ns_sbp[1]->s_last_cno) <
 238                             le64_to_cpu(nilfs->ns_sbp[0]->s_last_cno))
 239                                 sbp = nilfs->ns_sbp[1];
 240                 }
 241
 242                 spin_lock(&nilfs->ns_last_segment_lock);
 243                 nilfs->ns_prot_seq = le64_to_cpu(sbp->s_last_seq);
 244                 spin_unlock(&nilfs->ns_last_segment_lock);
 245         }
 246  out:
 247         return err;
 248 }
 249
 250 void nilfs_set_log_cursor(struct nilfs_super_block *sbp,
 251                           struct the_nilfs *nilfs)
 252 {
 253         sector_t nfreeblocks;
 254
 255         /* nilfs->ns_sem must be locked by the caller. */
 256         nilfs_count_free_blocks(nilfs, &nfreeblocks);
 257         sbp->s_free_blocks_count = cpu_to_le64(nfreeblocks);
 258
 259         spin_lock(&nilfs->ns_last_segment_lock);
 260         sbp->s_last_seq = cpu_to_le64(nilfs->ns_last_seq);
 261         sbp->s_last_pseg = cpu_to_le64(nilfs->ns_last_pseg);
 262         sbp->s_last_cno = cpu_to_le64(nilfs->ns_last_cno);
 263         spin_unlock(&nilfs->ns_last_segment_lock);
 264 }
 265
 266 struct nilfs_super_block **nilfs_prepare_super(struct nilfs_sb_info *sbi,
 267                                                int flip)
 268 {
 269         struct the_nilfs *nilfs = sbi->s_nilfs;
 270         struct nilfs_super_block **sbp = nilfs->ns_sbp;
 271
 272         /* nilfs->ns_sem must be locked by the caller. */
 273         if (sbp[0]->s_magic != cpu_to_le16(NILFS_SUPER_MAGIC)) {
 274                 if (sbp[1] &&
 275                     sbp[1]->s_magic == cpu_to_le16(NILFS_SUPER_MAGIC)) {
 276                         memcpy(sbp[0], sbp[1], nilfs->ns_sbsize);
 277                 } else {
 278                         printk(KERN_CRIT "NILFS: superblock broke on dev %s\n",
 279                                sbi->s_super->s_id);
 280                         return NULL;
 281                 }
 282         } else if (sbp[1] &&
 283                    sbp[1]->s_magic != cpu_to_le16(NILFS_SUPER_MAGIC)) {
 284                         memcpy(sbp[1], sbp[0], nilfs->ns_sbsize);
 285         }
 286
 287         if (flip && sbp[1])
 288                 nilfs_swap_super_block(nilfs);
 289
 290         return sbp;
 291 }
 292
 293 int nilfs_commit_super(struct nilfs_sb_info *sbi, int flag)
 294 {
 295         struct the_nilfs *nilfs = sbi->s_nilfs;
 296         struct nilfs_super_block **sbp = nilfs->ns_sbp;
 297         time_t t;
 298
 299         /* nilfs->ns_sem must be locked by the caller. */
 300         t = get_seconds();
 301         nilfs->ns_sbwtime = t;
 302         sbp[0]->s_wtime = cpu_to_le64(t);
 303         sbp[0]->s_sum = 0;
 304         sbp[0]->s_sum = cpu_to_le32(crc32_le(nilfs->ns_crc_seed,
 305                                              (unsigned char *)sbp[0],
 306                                              nilfs->ns_sbsize));
 307         if (flag == NILFS_SB_COMMIT_ALL && sbp[1]) {
 308                 sbp[1]->s_wtime = sbp[0]->s_wtime;
 309                 sbp[1]->s_sum = 0;
 310                 sbp[1]->s_sum = cpu_to_le32(crc32_le(nilfs->ns_crc_seed,
 311                                             (unsigned char *)sbp[1],
 312                                             nilfs->ns_sbsize));
 313         }
 314         clear_nilfs_sb_dirty(nilfs);
 315         return nilfs_sync_super(sbi, flag);
 316 }
 317
 318 /**
 319  * nilfs_cleanup_super() - write filesystem state for cleanup
 320  * @sbi: nilfs_sb_info to be unmounted or degraded to read-only
 321  *
 322  * This function restores state flags in the on-disk super block.
 323  * This will set "clean" flag (i.e. NILFS_VALID_FS) unless the
 324  * filesystem was not clean previously.
 325  */
 326 int nilfs_cleanup_super(struct nilfs_sb_info *sbi)
 327 {
 328         struct nilfs_super_block **sbp;
 329         int flag = NILFS_SB_COMMIT;
 330         int ret = -EIO;
 331
 332         sbp = nilfs_prepare_super(sbi, 0);
 333         if (sbp) {
 334                 sbp[0]->s_state = cpu_to_le16(sbi->s_nilfs->ns_mount_state);
 335                 nilfs_set_log_cursor(sbp[0], sbi->s_nilfs);
 336                 if (sbp[1] && sbp[0]->s_last_cno == sbp[1]->s_last_cno) {
 337                         /*
 338                          * make the "clean" flag also to the opposite
 339                          * super block if both super blocks point to
 340                          * the same checkpoint.
 341                          */
 342                         sbp[1]->s_state = sbp[0]->s_state;
 343                         flag = NILFS_SB_COMMIT_ALL;
 344                 }
 345                 ret = nilfs_commit_super(sbi, flag);
 346         }
 347         return ret;
 348 }
 349
 350 static void nilfs_put_super(struct super_block *sb)
 351 {
 352         struct nilfs_sb_info *sbi = NILFS_SB(sb);
 353         struct the_nilfs *nilfs = sbi->s_nilfs;
 354
 355         nilfs_detach_segment_constructor(sbi);
 356
 357         if (!(sb->s_flags & MS_RDONLY)) {
 358                 down_write(&nilfs->ns_sem);
 359                 nilfs_cleanup_super(sbi);
 360                 up_write(&nilfs->ns_sem);
 361         }
 362
 363         iput(nilfs->ns_sufile);
 364         iput(nilfs->ns_cpfile);
 365         iput(nilfs->ns_dat);
 366
 367         destroy_nilfs(nilfs);
 368         sbi->s_super = NULL;
 369         sb->s_fs_info = NULL;
 370         kfree(sbi);
 371 }
 372
 373 static int nilfs_sync_fs(struct super_block *sb, int wait)
 374 {
 375         struct nilfs_sb_info *sbi = NILFS_SB(sb);
 376         struct the_nilfs *nilfs = sbi->s_nilfs;
 377         struct nilfs_super_block **sbp;
 378         int err = 0;
 379
 380         /* This function is called when super block should be written back */
 381         if (wait)
 382                 err = nilfs_construct_segment(sb);
 383
 384         down_write(&nilfs->ns_sem);
 385         if (nilfs_sb_dirty(nilfs)) {
 386                 sbp = nilfs_prepare_super(sbi, nilfs_sb_will_flip(nilfs));
 387                 if (likely(sbp)) {
 388                         nilfs_set_log_cursor(sbp[0], nilfs);
 389                         nilfs_commit_super(sbi, NILFS_SB_COMMIT);
 390                 }
 391         }
 392         up_write(&nilfs->ns_sem);
 393
 394         return err;
 395 }
 396
 397 int nilfs_attach_checkpoint(struct nilfs_sb_info *sbi, __u64 cno, int curr_mnt,
 398                             struct nilfs_root **rootp)
 399 {
 400         struct the_nilfs *nilfs = sbi->s_nilfs;
 401         struct nilfs_root *root;
 402         struct nilfs_checkpoint *raw_cp;
 403         struct buffer_head *bh_cp;
 404         int err = -ENOMEM;
 405
 406         root = nilfs_find_or_create_root(
 407                 nilfs, curr_mnt ? NILFS_CPTREE_CURRENT_CNO : cno);
 408         if (!root)
 409                 return err;
 410
 411         if (root->ifile)
 412                 goto reuse; /* already attached checkpoint */
 413
 414         down_read(&nilfs->ns_segctor_sem);
 415         err = nilfs_cpfile_get_checkpoint(nilfs->ns_cpfile, cno, 0, &raw_cp,
 416                                           &bh_cp);
 417         up_read(&nilfs->ns_segctor_sem);
 418         if (unlikely(err)) {
 419                 if (err == -ENOENT || err == -EINVAL) {
 420                         printk(KERN_ERR
 421                                "NILFS: Invalid checkpoint "
 422                                "(checkpoint number=%llu)\n",
 423                                (unsigned long long)cno);
 424                         err = -EINVAL;
 425                 }
 426                 goto failed;
 427         }
 428
 429         err = nilfs_ifile_read(sbi->s_super, root, nilfs->ns_inode_size,
 430                                &raw_cp->cp_ifile_inode, &root->ifile);
 431         if (err)
 432                 goto failed_bh;
 433
 434         atomic_set(&root->inodes_count, le64_to_cpu(raw_cp->cp_inodes_count));
 435         atomic_set(&root->blocks_count, le64_to_cpu(raw_cp->cp_blocks_count));
 436
 437         nilfs_cpfile_put_checkpoint(nilfs->ns_cpfile, cno, bh_cp);
 438
 439  reuse:
 440         *rootp = root;
 441         return 0;
 442
 443  failed_bh:
 444         nilfs_cpfile_put_checkpoint(nilfs->ns_cpfile, cno, bh_cp);
 445  failed:
 446         nilfs_put_root(root);
 447
 448         return err;
 449 }
 450
 451 static int nilfs_freeze(struct super_block *sb)
 452 {
 453         struct nilfs_sb_info *sbi = NILFS_SB(sb);
 454         struct the_nilfs *nilfs = sbi->s_nilfs;
 455         int err;
 456
 457         if (sb->s_flags & MS_RDONLY)
 458                 return 0;
 459
 460         /* Mark super block clean */
 461         down_write(&nilfs->ns_sem);
 462         err = nilfs_cleanup_super(sbi);
 463         up_write(&nilfs->ns_sem);
 464         return err;
 465 }
 466
 467 static int nilfs_unfreeze(struct super_block *sb)
 468 {
 469         struct nilfs_sb_info *sbi = NILFS_SB(sb);
 470         struct the_nilfs *nilfs = sbi->s_nilfs;
 471
 472         if (sb->s_flags & MS_RDONLY)
 473                 return 0;
 474
 475         down_write(&nilfs->ns_sem);
 476         nilfs_setup_super(sbi, false);
 477         up_write(&nilfs->ns_sem);
 478         return 0;
 479 }
 480
 481 static int nilfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 482 {
 483         struct super_block *sb = dentry->d_sb;
 484         struct nilfs_root *root = NILFS_I(dentry->d_inode)->i_root;
 485         struct the_nilfs *nilfs = root->nilfs;
 486         u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
 487         unsigned long long blocks;
 488         unsigned long overhead;
 489         unsigned long nrsvblocks;
 490         sector_t nfreeblocks;
 491         int err;
 492
 493         /*
 494          * Compute all of the segment blocks
 495          *
 496          * The blocks before first segment and after last segment
 497          * are excluded.
 498          */
 499         blocks = nilfs->ns_blocks_per_segment * nilfs->ns_nsegments
 500                 - nilfs->ns_first_data_block;
 501         nrsvblocks = nilfs->ns_nrsvsegs * nilfs->ns_blocks_per_segment;
 502
 503         /*
 504          * Compute the overhead
 505          *
 506          * When distributing meta data blocks outside segment structure,
 507          * We must count them as the overhead.
 508          */
 509         overhead = 0;
 510
 511         err = nilfs_count_free_blocks(nilfs, &nfreeblocks);
 512         if (unlikely(err))
 513                 return err;
 514
 515         buf->f_type = NILFS_SUPER_MAGIC;
 516         buf->f_bsize = sb->s_blocksize;
 517         buf->f_blocks = blocks - overhead;
 518         buf->f_bfree = nfreeblocks;
 519         buf->f_bavail = (buf->f_bfree >= nrsvblocks) ?
 520                 (buf->f_bfree - nrsvblocks) : 0;
 521         buf->f_files = atomic_read(&root->inodes_count);
 522         buf->f_ffree = 0; /* nilfs_count_free_inodes(sb); */
 523         buf->f_namelen = NILFS_NAME_LEN;
 524         buf->f_fsid.val[0] = (u32)id;
 525         buf->f_fsid.val[1] = (u32)(id >> 32);
 526
 527         return 0;
 528 }
 529
 530 static int nilfs_show_options(struct seq_file *seq, struct vfsmount *vfs)
 531 {
 532         struct super_block *sb = vfs->mnt_sb;
 533         struct nilfs_sb_info *sbi = NILFS_SB(sb);
 534         struct nilfs_root *root = NILFS_I(vfs->mnt_root->d_inode)->i_root;
 535
 536         if (!nilfs_test_opt(sbi, BARRIER))
 537                 seq_puts(seq, ",nobarrier");
 538         if (root->cno != NILFS_CPTREE_CURRENT_CNO)
 539                 seq_printf(seq, ",cp=%llu", (unsigned long long)root->cno);
 540         if (nilfs_test_opt(sbi, ERRORS_PANIC))
 541                 seq_puts(seq, ",errors=panic");
 542         if (nilfs_test_opt(sbi, ERRORS_CONT))
 543                 seq_puts(seq, ",errors=continue");
 544         if (nilfs_test_opt(sbi, STRICT_ORDER))
 545                 seq_puts(seq, ",order=strict");
 546         if (nilfs_test_opt(sbi, NORECOVERY))
 547                 seq_puts(seq, ",norecovery");
 548         if (nilfs_test_opt(sbi, DISCARD))
 549                 seq_puts(seq, ",discard");
 550
 551         return 0;
 552 }
 553
 554 static const struct super_operations nilfs_sops = {
 555         .alloc_inode    = nilfs_alloc_inode,
 556         .destroy_inode  = nilfs_destroy_inode,
 557         .dirty_inode    = nilfs_dirty_inode,
 558         /* .write_inode    = nilfs_write_inode, */
 559         /* .put_inode      = nilfs_put_inode, */
 560         /* .drop_inode    = nilfs_drop_inode, */
 561         .evict_inode    = nilfs_evict_inode,
 562         .put_super      = nilfs_put_super,
 563         /* .write_super    = nilfs_write_super, */
 564         .sync_fs        = nilfs_sync_fs,
 565         .freeze_fs      = nilfs_freeze,
 566         .unfreeze_fs    = nilfs_unfreeze,
 567         /* .write_super_lockfs */
 568         /* .unlockfs */
 569         .statfs         = nilfs_statfs,
 570         .remount_fs     = nilfs_remount,
 571         /* .umount_begin */
 572         .show_options = nilfs_show_options
 573 };
 574
 575 enum {
 576         Opt_err_cont, Opt_err_panic, Opt_err_ro,
 577         Opt_barrier, Opt_nobarrier, Opt_snapshot, Opt_order, Opt_norecovery,
 578         Opt_discard, Opt_nodiscard, Opt_err,
 579 };
 580
 581 static match_table_t tokens = {
 582         {Opt_err_cont, "errors=continue"},
 583         {Opt_err_panic, "errors=panic"},
 584         {Opt_err_ro, "errors=remount-ro"},
 585         {Opt_barrier, "barrier"},
 586         {Opt_nobarrier, "nobarrier"},
 587         {Opt_snapshot, "cp=%u"},
 588         {Opt_order, "order=%s"},
 589         {Opt_norecovery, "norecovery"},
 590         {Opt_discard, "discard"},
 591         {Opt_nodiscard, "nodiscard"},
 592         {Opt_err, NULL}
 593 };
 594
 595 static int parse_options(char *options, struct super_block *sb, int is_remount)
 596 {
 597         struct nilfs_sb_info *sbi = NILFS_SB(sb);
 598         char *p;
 599         substring_t args[MAX_OPT_ARGS];
 600
 601         if (!options)
 602                 return 1;
 603
 604         while ((p = strsep(&options, ",")) != NULL) {
 605                 int token;
 606                 if (!*p)
 607                         continue;
 608
 609                 token = match_token(p, tokens, args);
 610                 switch (token) {
 611                 case Opt_barrier:
 612                         nilfs_set_opt(sbi, BARRIER);
 613                         break;
 614                 case Opt_nobarrier:
 615                         nilfs_clear_opt(sbi, BARRIER);
 616                         break;
 617                 case Opt_order:
 618                         if (strcmp(args[0].from, "relaxed") == 0)
 619                                 /* Ordered data semantics */
 620                                 nilfs_clear_opt(sbi, STRICT_ORDER);
 621                         else if (strcmp(args[0].from, "strict") == 0)
 622                                 /* Strict in-order semantics */
 623                                 nilfs_set_opt(sbi, STRICT_ORDER);
 624                         else
 625                                 return 0;
 626                         break;
 627                 case Opt_err_panic:
 628                         nilfs_write_opt(sbi, ERROR_MODE, ERRORS_PANIC);
 629                         break;
 630                 case Opt_err_ro:
 631                         nilfs_write_opt(sbi, ERROR_MODE, ERRORS_RO);
 632                         break;
 633                 case Opt_err_cont:
 634                         nilfs_write_opt(sbi, ERROR_MODE, ERRORS_CONT);
 635                         break;
 636                 case Opt_snapshot:
 637                         if (is_remount) {
 638                                 printk(KERN_ERR
 639                                        "NILFS: \"%s\" option is invalid "
 640                                        "for remount.\n", p);
 641                                 return 0;
 642                         }
 643                         break;
 644                 case Opt_norecovery:
 645                         nilfs_set_opt(sbi, NORECOVERY);
 646                         break;
 647                 case Opt_discard:
 648                         nilfs_set_opt(sbi, DISCARD);
 649                         break;
 650                 case Opt_nodiscard:
 651                         nilfs_clear_opt(sbi, DISCARD);
 652                         break;
 653                 default:
 654                         printk(KERN_ERR
 655                                "NILFS: Unrecognized mount option \"%s\"\n", p);
 656                         return 0;
 657                 }
 658         }
 659         return 1;
 660 }
 661
 662 static inline void
 663 nilfs_set_default_options(struct nilfs_sb_info *sbi,
 664                           struct nilfs_super_block *sbp)
 665 {
 666         sbi->s_mount_opt =
 667                 NILFS_MOUNT_ERRORS_RO | NILFS_MOUNT_BARRIER;
 668 }
 669
 670 static int nilfs_setup_super(struct nilfs_sb_info *sbi, int is_mount)
 671 {
 672         struct the_nilfs *nilfs = sbi->s_nilfs;
 673         struct nilfs_super_block **sbp;
 674         int max_mnt_count;
 675         int mnt_count;
 676
 677         /* nilfs->ns_sem must be locked by the caller. */
 678         sbp = nilfs_prepare_super(sbi, 0);
 679         if (!sbp)
 680                 return -EIO;
 681
 682         if (!is_mount)
 683                 goto skip_mount_setup;
 684
 685         max_mnt_count = le16_to_cpu(sbp[0]->s_max_mnt_count);
 686         mnt_count = le16_to_cpu(sbp[0]->s_mnt_count);
 687
 688         if (nilfs->ns_mount_state & NILFS_ERROR_FS) {
 689                 printk(KERN_WARNING
 690                        "NILFS warning: mounting fs with errors\n");
 691 #if 0
 692         } else if (max_mnt_count >= 0 && mnt_count >= max_mnt_count) {
 693                 printk(KERN_WARNING
 694                        "NILFS warning: maximal mount count reached\n");
 695 #endif
 696         }
 697         if (!max_mnt_count)
 698                 sbp[0]->s_max_mnt_count = cpu_to_le16(NILFS_DFL_MAX_MNT_COUNT);
 699
 700         sbp[0]->s_mnt_count = cpu_to_le16(mnt_count + 1);
 701         sbp[0]->s_mtime = cpu_to_le64(get_seconds());
 702
 703 skip_mount_setup:
 704         sbp[0]->s_state =
 705                 cpu_to_le16(le16_to_cpu(sbp[0]->s_state) & ~NILFS_VALID_FS);
 706         /* synchronize sbp[1] with sbp[0] */
 707         if (sbp[1])
 708                 memcpy(sbp[1], sbp[0], nilfs->ns_sbsize);
 709         return nilfs_commit_super(sbi, NILFS_SB_COMMIT_ALL);
 710 }
 711
 712 struct nilfs_super_block *nilfs_read_super_block(struct super_block *sb,
 713                                                  u64 pos, int blocksize,
 714                                                  struct buffer_head **pbh)
 715 {
 716         unsigned long long sb_index = pos;
 717         unsigned long offset;
 718
 719         offset = do_div(sb_index, blocksize);
 720         *pbh = sb_bread(sb, sb_index);
 721         if (!*pbh)
 722                 return NULL;
 723         return (struct nilfs_super_block *)((char *)(*pbh)->b_data + offset);
 724 }
 725
 726 int nilfs_store_magic_and_option(struct super_block *sb,
 727                                  struct nilfs_super_block *sbp,
 728                                  char *data)
 729 {
 730         struct nilfs_sb_info *sbi = NILFS_SB(sb);
 731
 732         sb->s_magic = le16_to_cpu(sbp->s_magic);
 733
 734         /* FS independent flags */
 735 #ifdef NILFS_ATIME_DISABLE
 736         sb->s_flags |= MS_NOATIME;
 737 #endif
 738
 739         nilfs_set_default_options(sbi, sbp);
 740
 741         sbi->s_resuid = le16_to_cpu(sbp->s_def_resuid);
 742         sbi->s_resgid = le16_to_cpu(sbp->s_def_resgid);
 743         sbi->s_interval = le32_to_cpu(sbp->s_c_interval);
 744         sbi->s_watermark = le32_to_cpu(sbp->s_c_block_max);
 745
 746         return !parse_options(data, sb, 0) ? -EINVAL : 0 ;
 747 }
 748
 749 int nilfs_check_feature_compatibility(struct super_block *sb,
 750                                       struct nilfs_super_block *sbp)
 751 {
 752         __u64 features;
 753
 754         features = le64_to_cpu(sbp->s_feature_incompat) &
 755                 ~NILFS_FEATURE_INCOMPAT_SUPP;
 756         if (features) {
 757                 printk(KERN_ERR "NILFS: couldn't mount because of unsupported "
 758                        "optional features (%llx)\n",
 759                        (unsigned long long)features);
 760                 return -EINVAL;
 761         }
 762         features = le64_to_cpu(sbp->s_feature_compat_ro) &
 763                 ~NILFS_FEATURE_COMPAT_RO_SUPP;
 764         if (!(sb->s_flags & MS_RDONLY) && features) {
 765                 printk(KERN_ERR "NILFS: couldn't mount RDWR because of "
 766                        "unsupported optional features (%llx)\n",
 767                        (unsigned long long)features);
 768                 return -EINVAL;
 769         }
 770         return 0;
 771 }
 772
 773 static int nilfs_get_root_dentry(struct super_block *sb,
 774                                  struct nilfs_root *root,
 775                                  struct dentry **root_dentry)
 776 {
 777         struct inode *inode;
 778         struct dentry *dentry;
 779         int ret = 0;
 780
 781         inode = nilfs_iget(sb, root, NILFS_ROOT_INO);
 782         if (IS_ERR(inode)) {
 783                 printk(KERN_ERR "NILFS: get root inode failed\n");
 784                 ret = PTR_ERR(inode);
 785                 goto out;
 786         }
 787         if (!S_ISDIR(inode->i_mode) || !inode->i_blocks || !inode->i_size) {
 788                 iput(inode);
 789                 printk(KERN_ERR "NILFS: corrupt root inode.\n");
 790                 ret = -EINVAL;
 791                 goto out;
 792         }
 793
 794         if (root->cno == NILFS_CPTREE_CURRENT_CNO) {
 795                 dentry = d_find_alias(inode);
 796                 if (!dentry) {
 797                         dentry = d_alloc_root(inode);
 798                         if (!dentry) {
 799                                 iput(inode);
 800                                 ret = -ENOMEM;
 801                                 goto failed_dentry;
 802                         }
 803                 } else {
 804                         iput(inode);
 805                 }
 806         } else {
 807                 dentry = d_obtain_alias(inode);
 808                 if (IS_ERR(dentry)) {
 809                         ret = PTR_ERR(dentry);
 810                         goto failed_dentry;
 811                 }
 812         }
 813         *root_dentry = dentry;
 814  out:
 815         return ret;
 816
 817  failed_dentry:
 818         printk(KERN_ERR "NILFS: get root dentry failed\n");
 819         goto out;
 820 }
 821
 822 static int nilfs_attach_snapshot(struct super_block *s, __u64 cno,
 823                                  struct dentry **root_dentry)
 824 {
 825         struct the_nilfs *nilfs = NILFS_SB(s)->s_nilfs;
 826         struct nilfs_root *root;
 827         int ret;
 828
 829         down_read(&nilfs->ns_segctor_sem);
 830         ret = nilfs_cpfile_is_snapshot(nilfs->ns_cpfile, cno);
 831         up_read(&nilfs->ns_segctor_sem);
 832         if (ret < 0) {
 833                 ret = (ret == -ENOENT) ? -EINVAL : ret;
 834                 goto out;
 835         } else if (!ret) {
 836                 printk(KERN_ERR "NILFS: The specified checkpoint is "
 837                        "not a snapshot (checkpoint number=%llu).\n",
 838                        (unsigned long long)cno);
 839                 ret = -EINVAL;
 840                 goto out;
 841         }
 842
 843         ret = nilfs_attach_checkpoint(NILFS_SB(s), cno, false, &root);
 844         if (ret) {
 845                 printk(KERN_ERR "NILFS: error loading snapshot "
 846                        "(checkpoint number=%llu).\n",
 847                (unsigned long long)cno);
 848                 goto out;
 849         }
 850         ret = nilfs_get_root_dentry(s, root, root_dentry);
 851         nilfs_put_root(root);
 852  out:
 853         return ret;
 854 }
 855
 856 static int nilfs_tree_was_touched(struct dentry *root_dentry)
 857 {
 858         return root_dentry->d_count > 1;
 859 }
 860
 861 /**
 862  * nilfs_try_to_shrink_tree() - try to shrink dentries of a checkpoint
 863  * @root_dentry: root dentry of the tree to be shrunk
 864  *
 865  * This function returns true if the tree was in-use.
 866  */
 867 static int nilfs_try_to_shrink_tree(struct dentry *root_dentry)
 868 {
 869         if (have_submounts(root_dentry))
 870                 return true;
 871         shrink_dcache_parent(root_dentry);
 872         return nilfs_tree_was_touched(root_dentry);
 873 }
 874
 875 int nilfs_checkpoint_is_mounted(struct super_block *sb, __u64 cno)
 876 {
 877         struct the_nilfs *nilfs = NILFS_SB(sb)->s_nilfs;
 878         struct nilfs_root *root;
 879         struct inode *inode;
 880         struct dentry *dentry;
 881         int ret;
 882
 883         if (cno < 0 || cno > nilfs->ns_cno)
 884                 return false;
 885
 886         if (cno >= nilfs_last_cno(nilfs))
 887                 return true;    /* protect recent checkpoints */
 888
 889         ret = false;
 890         root = nilfs_lookup_root(NILFS_SB(sb)->s_nilfs, cno);
 891         if (root) {
 892                 inode = nilfs_ilookup(sb, root, NILFS_ROOT_INO);
 893                 if (inode) {
 894                         dentry = d_find_alias(inode);
 895                         if (dentry) {
 896                                 if (nilfs_tree_was_touched(dentry))
 897                                         ret = nilfs_try_to_shrink_tree(dentry);
 898                                 dput(dentry);
 899                         }
 900                         iput(inode);
 901                 }
 902                 nilfs_put_root(root);
 903         }
 904         return ret;
 905 }
 906
 907 /**
 908  * nilfs_fill_super() - initialize a super block instance
 909  * @sb: super_block
 910  * @data: mount options
 911  * @silent: silent mode flag
 912  *
 913  * This function is called exclusively by nilfs->ns_mount_mutex.
 914  * So, the recovery process is protected from other simultaneous mounts.
 915  */
 916 static int
 917 nilfs_fill_super(struct super_block *sb, void *data, int silent)
 918 {
 919         struct the_nilfs *nilfs;
 920         struct nilfs_sb_info *sbi;
 921         struct nilfs_root *fsroot;
 922         struct backing_dev_info *bdi;
 923         __u64 cno;
 924         int err;
 925
 926         sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
 927         if (!sbi)
 928                 return -ENOMEM;
 929
 930         sb->s_fs_info = sbi;
 931         sbi->s_super = sb;
 932
 933         nilfs = alloc_nilfs(sb->s_bdev);
 934         if (!nilfs) {
 935                 err = -ENOMEM;
 936                 goto failed_sbi;
 937         }
 938         sbi->s_nilfs = nilfs;
 939
 940         err = init_nilfs(nilfs, sbi, (char *)data);
 941         if (err)
 942                 goto failed_nilfs;
 943
 944         spin_lock_init(&sbi->s_inode_lock);
 945         INIT_LIST_HEAD(&sbi->s_dirty_files);
 946
 947         /*
 948          * Following initialization is overlapped because
 949          * nilfs_sb_info structure has been cleared at the beginning.
 950          * But we reserve them to keep our interest and make ready
 951          * for the future change.
 952          */
 953         get_random_bytes(&sbi->s_next_generation,
 954                          sizeof(sbi->s_next_generation));
 955         spin_lock_init(&sbi->s_next_gen_lock);
 956
 957         sb->s_op = &nilfs_sops;
 958         sb->s_export_op = &nilfs_export_ops;
 959         sb->s_root = NULL;
 960         sb->s_time_gran = 1;
 961
 962         bdi = sb->s_bdev->bd_inode->i_mapping->backing_dev_info;
 963         sb->s_bdi = bdi ? : &default_backing_dev_info;
 964
 965         err = load_nilfs(nilfs, sbi);
 966         if (err)
 967                 goto failed_nilfs;
 968
 969         cno = nilfs_last_cno(nilfs);
 970         err = nilfs_attach_checkpoint(sbi, cno, true, &fsroot);
 971         if (err) {
 972                 printk(KERN_ERR "NILFS: error loading last checkpoint "
 973                        "(checkpoint number=%llu).\n", (unsigned long long)cno);
 974                 goto failed_unload;
 975         }
 976
 977         if (!(sb->s_flags & MS_RDONLY)) {
 978                 err = nilfs_attach_segment_constructor(sbi, fsroot);
 979                 if (err)
 980                         goto failed_checkpoint;
 981         }
 982
 983         err = nilfs_get_root_dentry(sb, fsroot, &sb->s_root);
 984         if (err)
 985                 goto failed_segctor;
 986
 987         nilfs_put_root(fsroot);
 988
 989         if (!(sb->s_flags & MS_RDONLY)) {
 990                 down_write(&nilfs->ns_sem);
 991                 nilfs_setup_super(sbi, true);
 992                 up_write(&nilfs->ns_sem);
 993         }
 994
 995         return 0;
 996
 997  failed_segctor:
 998         nilfs_detach_segment_constructor(sbi);
 999
1000  failed_checkpoint:
1001         nilfs_put_root(fsroot);
1002
1003  failed_unload:
1004         iput(nilfs->ns_sufile);
1005         iput(nilfs->ns_cpfile);
1006         iput(nilfs->ns_dat);
1007
1008  failed_nilfs:
1009         destroy_nilfs(nilfs);
1010
1011  failed_sbi:
1012         sb->s_fs_info = NULL;
1013         kfree(sbi);
1014         return err;
1015 }
1016
1017 static int nilfs_remount(struct super_block *sb, int *flags, char *data)
1018 {
1019         struct nilfs_sb_info *sbi = NILFS_SB(sb);
1020         struct the_nilfs *nilfs = sbi->s_nilfs;
1021         unsigned long old_sb_flags;
1022         unsigned long old_mount_opt;
1023         int err;
1024
1025         old_sb_flags = sb->s_flags;
1026         old_mount_opt = sbi->s_mount_opt;
1027
1028         if (!parse_options(data, sb, 1)) {
1029                 err = -EINVAL;
1030                 goto restore_opts;
1031         }
1032         sb->s_flags = (sb->s_flags & ~MS_POSIXACL);
1033
1034         err = -EINVAL;
1035
1036         if (!nilfs_valid_fs(nilfs)) {
1037                 printk(KERN_WARNING "NILFS (device %s): couldn't "
1038                        "remount because the filesystem is in an "
1039                        "incomplete recovery state.\n", sb->s_id);
1040                 goto restore_opts;
1041         }
1042
1043         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
1044                 goto out;
1045         if (*flags & MS_RDONLY) {
1046                 /* Shutting down the segment constructor */
1047                 nilfs_detach_segment_constructor(sbi);
1048                 sb->s_flags |= MS_RDONLY;
1049
1050                 /*
1051                  * Remounting a valid RW partition RDONLY, so set
1052                  * the RDONLY flag and then mark the partition as valid again.
1053                  */
1054                 down_write(&nilfs->ns_sem);
1055                 nilfs_cleanup_super(sbi);
1056                 up_write(&nilfs->ns_sem);
1057         } else {
1058                 __u64 features;
1059                 struct nilfs_root *root;
1060
1061                 /*
1062                  * Mounting a RDONLY partition read-write, so reread and
1063                  * store the current valid flag.  (It may have been changed
1064                  * by fsck since we originally mounted the partition.)
1065                  */
1066                 down_read(&nilfs->ns_sem);
1067                 features = le64_to_cpu(nilfs->ns_sbp[0]->s_feature_compat_ro) &
1068                         ~NILFS_FEATURE_COMPAT_RO_SUPP;
1069                 up_read(&nilfs->ns_sem);
1070                 if (features) {
1071                         printk(KERN_WARNING "NILFS (device %s): couldn't "
1072                                "remount RDWR because of unsupported optional "
1073                                "features (%llx)\n",
1074                                sb->s_id, (unsigned long long)features);
1075                         err = -EROFS;
1076                         goto restore_opts;
1077                 }
1078
1079                 sb->s_flags &= ~MS_RDONLY;
1080
1081                 root = NILFS_I(sb->s_root->d_inode)->i_root;
1082                 err = nilfs_attach_segment_constructor(sbi, root);
1083                 if (err)
1084                         goto restore_opts;
1085
1086                 down_write(&nilfs->ns_sem);
1087                 nilfs_setup_super(sbi, true);
1088                 up_write(&nilfs->ns_sem);
1089         }
1090  out:
1091         return 0;
1092
1093  restore_opts:
1094         sb->s_flags = old_sb_flags;
1095         sbi->s_mount_opt = old_mount_opt;
1096         return err;
1097 }
1098
1099 struct nilfs_super_data {
1100         struct block_device *bdev;
1101         struct nilfs_sb_info *sbi;
1102         __u64 cno;
1103         int flags;
1104 };
1105
1106 /**
1107  * nilfs_identify - pre-read mount options needed to identify mount instance
1108  * @data: mount options
1109  * @sd: nilfs_super_data
1110  */
1111 static int nilfs_identify(char *data, struct nilfs_super_data *sd)
1112 {
1113         char *p, *options = data;
1114         substring_t args[MAX_OPT_ARGS];
1115         int token;
1116         int ret = 0;
1117
1118         do {
1119                 p = strsep(&options, ",");
1120                 if (p != NULL && *p) {
1121                         token = match_token(p, tokens, args);
1122                         if (token == Opt_snapshot) {
1123                                 if (!(sd->flags & MS_RDONLY)) {
1124                                         ret++;
1125                                 } else {
1126                                         sd->cno = simple_strtoull(args[0].from,
1127                                                                   NULL, 0);
1128                                         /*
1129                                          * No need to see the end pointer;
1130                                          * match_token() has done syntax
1131                                          * checking.
1132                                          */
1133                                         if (sd->cno == 0)
1134                                                 ret++;
1135                                 }
1136                         }
1137                         if (ret)
1138                                 printk(KERN_ERR
1139                                        "NILFS: invalid mount option: %s\n", p);
1140                 }
1141                 if (!options)
1142                         break;
1143                 BUG_ON(options == data);
1144                 *(options - 1) = ',';
1145         } while (!ret);
1146         return ret;
1147 }
1148
1149 static int nilfs_set_bdev_super(struct super_block *s, void *data)
1150 {
1151         s->s_bdev = data;
1152         s->s_dev = s->s_bdev->bd_dev;
1153         return 0;
1154 }
1155
1156 static int nilfs_test_bdev_super(struct super_block *s, void *data)
1157 {
1158         return (void *)s->s_bdev == data;
1159 }
1160
1161 static struct dentry *
1162 nilfs_mount(struct file_system_type *fs_type, int flags,
1163              const char *dev_name, void *data)
1164 {
1165         struct nilfs_super_data sd;
1166         struct super_block *s;
1167         fmode_t mode = FMODE_READ | FMODE_EXCL;
1168         struct dentry *root_dentry;
1169         int err, s_new = false;
1170
1171         if (!(flags & MS_RDONLY))
1172                 mode |= FMODE_WRITE;
1173
1174         sd.bdev = blkdev_get_by_path(dev_name, mode, fs_type);
1175         if (IS_ERR(sd.bdev))
1176                 return ERR_CAST(sd.bdev);
1177
1178         sd.cno = 0;
1179         sd.flags = flags;
1180         if (nilfs_identify((char *)data, &sd)) {
1181                 err = -EINVAL;
1182                 goto failed;
1183         }
1184
1185         /*
1186          * once the super is inserted into the list by sget, s_umount
1187          * will protect the lockfs code from trying to start a snapshot
1188          * while we are mounting
1189          */
1190         mutex_lock(&sd.bdev->bd_fsfreeze_mutex);
1191         if (sd.bdev->bd_fsfreeze_count > 0) {
1192                 mutex_unlock(&sd.bdev->bd_fsfreeze_mutex);
1193                 err = -EBUSY;
1194                 goto failed;
1195         }
1196         s = sget(fs_type, nilfs_test_bdev_super, nilfs_set_bdev_super, sd.bdev);
1197         mutex_unlock(&sd.bdev->bd_fsfreeze_mutex);
1198         if (IS_ERR(s)) {
1199                 err = PTR_ERR(s);
1200                 goto failed;
1201         }
1202
1203         if (!s->s_root) {
1204                 char b[BDEVNAME_SIZE];
1205
1206                 s_new = true;
1207
1208                 /* New superblock instance created */
1209                 s->s_flags = flags;
1210                 s->s_mode = mode;
1211                 strlcpy(s->s_id, bdevname(sd.bdev, b), sizeof(s->s_id));
1212                 sb_set_blocksize(s, block_size(sd.bdev));
1213
1214                 err = nilfs_fill_super(s, data, flags & MS_SILENT ? 1 : 0);
1215                 if (err)
1216                         goto failed_super;
1217
1218                 s->s_flags |= MS_ACTIVE;
1219         } else if (!sd.cno) {
1220                 int busy = false;
1221
1222                 if (nilfs_tree_was_touched(s->s_root)) {
1223                         busy = nilfs_try_to_shrink_tree(s->s_root);
1224                         if (busy && (flags ^ s->s_flags) & MS_RDONLY) {
1225                                 printk(KERN_ERR "NILFS: the device already "
1226                                        "has a %s mount.\n",
1227                                        (s->s_flags & MS_RDONLY) ?
1228                                        "read-only" : "read/write");
1229                                 err = -EBUSY;
1230                                 goto failed_super;
1231                         }
1232                 }
1233                 if (!busy) {
1234                         /*
1235                          * Try remount to setup mount states if the current
1236                          * tree is not mounted and only snapshots use this sb.
1237                          */
1238                         err = nilfs_remount(s, &flags, data);
1239                         if (err)
1240                                 goto failed_super;
1241                 }
1242         }
1243
1244         if (sd.cno) {
1245                 err = nilfs_attach_snapshot(s, sd.cno, &root_dentry);
1246                 if (err)
1247                         goto failed_super;
1248         } else {
1249                 root_dentry = dget(s->s_root);
1250         }
1251
1252         if (!s_new)
1253                 blkdev_put(sd.bdev, mode);
1254
1255         return root_dentry;
1256
1257  failed_super:
1258         deactivate_locked_super(s);
1259
1260  failed:
1261         if (!s_new)
1262                 blkdev_put(sd.bdev, mode);
1263         return ERR_PTR(err);
1264 }
1265
1266 struct file_system_type nilfs_fs_type = {
1267         .owner    = THIS_MODULE,
1268         .name     = "nilfs2",
1269         .mount    = nilfs_mount,
1270         .kill_sb  = kill_block_super,
1271         .fs_flags = FS_REQUIRES_DEV,
1272 };
1273
1274 static void nilfs_inode_init_once(void *obj)
1275 {
1276         struct nilfs_inode_info *ii = obj;
1277
1278         INIT_LIST_HEAD(&ii->i_dirty);
1279 #ifdef CONFIG_NILFS_XATTR
1280         init_rwsem(&ii->xattr_sem);
1281 #endif
1282         address_space_init_once(&ii->i_btnode_cache);
1283         ii->i_bmap = &ii->i_bmap_data;
1284         inode_init_once(&ii->vfs_inode);
1285 }
1286
1287 static void nilfs_segbuf_init_once(void *obj)
1288 {
1289         memset(obj, 0, sizeof(struct nilfs_segment_buffer));
1290 }
1291
1292 static void nilfs_destroy_cachep(void)
1293 {
1294         if (nilfs_inode_cachep)
1295                 kmem_cache_destroy(nilfs_inode_cachep);
1296         if (nilfs_transaction_cachep)
1297                 kmem_cache_destroy(nilfs_transaction_cachep);
1298         if (nilfs_segbuf_cachep)
1299                 kmem_cache_destroy(nilfs_segbuf_cachep);
1300         if (nilfs_btree_path_cache)
1301                 kmem_cache_destroy(nilfs_btree_path_cache);
1302 }
1303
1304 static int __init nilfs_init_cachep(void)
1305 {
1306         nilfs_inode_cachep = kmem_cache_create("nilfs2_inode_cache",
1307                         sizeof(struct nilfs_inode_info), 0,
1308                         SLAB_RECLAIM_ACCOUNT, nilfs_inode_init_once);
1309         if (!nilfs_inode_cachep)
1310                 goto fail;
1311
1312         nilfs_transaction_cachep = kmem_cache_create("nilfs2_transaction_cache",
1313                         sizeof(struct nilfs_transaction_info), 0,
1314                         SLAB_RECLAIM_ACCOUNT, NULL);
1315         if (!nilfs_transaction_cachep)
1316                 goto fail;
1317
1318         nilfs_segbuf_cachep = kmem_cache_create("nilfs2_segbuf_cache",
1319                         sizeof(struct nilfs_segment_buffer), 0,
1320                         SLAB_RECLAIM_ACCOUNT, nilfs_segbuf_init_once);
1321         if (!nilfs_segbuf_cachep)
1322                 goto fail;
1323
1324         nilfs_btree_path_cache = kmem_cache_create("nilfs2_btree_path_cache",
1325                         sizeof(struct nilfs_btree_path) * NILFS_BTREE_LEVEL_MAX,
1326                         0, 0, NULL);
1327         if (!nilfs_btree_path_cache)
1328                 goto fail;
1329
1330         return 0;
1331
1332 fail:
1333         nilfs_destroy_cachep();
1334         return -ENOMEM;
1335 }
1336
1337 static int __init init_nilfs_fs(void)
1338 {
1339         int err;
1340
1341         err = nilfs_init_cachep();
1342         if (err)
1343                 goto fail;
1344
1345         err = register_filesystem(&nilfs_fs_type);
1346         if (err)
1347                 goto free_cachep;
1348
1349         printk(KERN_INFO "NILFS version 2 loaded\n");
1350         return 0;
1351
1352 free_cachep:
1353         nilfs_destroy_cachep();
1354 fail:
1355         return err;
1356 }
1357
1358 static void __exit exit_nilfs_fs(void)
1359 {
1360         nilfs_destroy_cachep();
1361         unregister_filesystem(&nilfs_fs_type);
1362 }
1363
1364 module_init(init_nilfs_fs)
1365 module_exit(exit_nilfs_fs)