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  * Written by Ryusuke Konishi.
  17  */
  18 /*
  19  *  linux/fs/ext2/super.c
  20  *
  21  * Copyright (C) 1992, 1993, 1994, 1995
  22  * Remy Card ([email protected])
  23  * Laboratoire MASI - Institut Blaise Pascal
  24  * Universite Pierre et Marie Curie (Paris VI)
  25  *
  26  *  from
  27  *
  28  *  linux/fs/minix/inode.c
  29  *
  30  *  Copyright (C) 1991, 1992  Linus Torvalds
  31  *
  32  *  Big-endian to little-endian byte-swapping/bitmaps by
  33  *        David S. Miller ([email protected]), 1995
  34  */
  35
  36 #include <linux/module.h>
  37 #include <linux/string.h>
  38 #include <linux/slab.h>
  39 #include <linux/init.h>
  40 #include <linux/blkdev.h>
  41 #include <linux/parser.h>
  42 #include <linux/crc32.h>
  43 #include <linux/vfs.h>
  44 #include <linux/writeback.h>
  45 #include <linux/seq_file.h>
  46 #include <linux/mount.h>
  47 #include "nilfs.h"
  48 #include "export.h"
  49 #include "mdt.h"
  50 #include "alloc.h"
  51 #include "btree.h"
  52 #include "btnode.h"
  53 #include "page.h"
  54 #include "cpfile.h"
  55 #include "sufile.h" /* nilfs_sufile_resize(), nilfs_sufile_set_alloc_range() */
  56 #include "ifile.h"
  57 #include "dat.h"
  58 #include "segment.h"
  59 #include "segbuf.h"
  60
  61 MODULE_AUTHOR("NTT Corp.");
  62 MODULE_DESCRIPTION("A New Implementation of the Log-structured Filesystem "
  63                    "(NILFS)");
  64 MODULE_LICENSE("GPL");
  65
  66 static struct kmem_cache *nilfs_inode_cachep;
  67 struct kmem_cache *nilfs_transaction_cachep;
  68 struct kmem_cache *nilfs_segbuf_cachep;
  69 struct kmem_cache *nilfs_btree_path_cache;
  70
  71 static int nilfs_setup_super(struct super_block *sb, int is_mount);
  72 static int nilfs_remount(struct super_block *sb, int *flags, char *data);
  73
  74 static void nilfs_set_error(struct super_block *sb)
  75 {
  76         struct the_nilfs *nilfs = sb->s_fs_info;
  77         struct nilfs_super_block **sbp;
  78
  79         down_write(&nilfs->ns_sem);
  80         if (!(nilfs->ns_mount_state & NILFS_ERROR_FS)) {
  81                 nilfs->ns_mount_state |= NILFS_ERROR_FS;
  82                 sbp = nilfs_prepare_super(sb, 0);
  83                 if (likely(sbp)) {
  84                         sbp[0]->s_state |= cpu_to_le16(NILFS_ERROR_FS);
  85                         if (sbp[1])
  86                                 sbp[1]->s_state |= cpu_to_le16(NILFS_ERROR_FS);
  87                         nilfs_commit_super(sb, NILFS_SB_COMMIT_ALL);
  88                 }
  89         }
  90         up_write(&nilfs->ns_sem);
  91 }
  92
  93 /**
  94  * nilfs_error() - report failure condition on a filesystem
  95  *
  96  * nilfs_error() sets an ERROR_FS flag on the superblock as well as
  97  * reporting an error message.  It should be called when NILFS detects
  98  * incoherences or defects of meta data on disk.  As for sustainable
  99  * errors such as a single-shot I/O error, nilfs_warning() or the printk()
 100  * function should be used instead.
 101  *
 102  * The segment constructor must not call this function because it can
 103  * kill itself.
 104  */
 105 void nilfs_error(struct super_block *sb, const char *function,
 106                  const char *fmt, ...)
 107 {
 108         struct the_nilfs *nilfs = sb->s_fs_info;
 109         struct va_format vaf;
 110         va_list args;
 111
 112         va_start(args, fmt);
 113
 114         vaf.fmt = fmt;
 115         vaf.va = &args;
 116
 117         printk(KERN_CRIT "NILFS error (device %s): %s: %pV\n",
 118                sb->s_id, function, &vaf);
 119
 120         va_end(args);
 121
 122         if (!(sb->s_flags & MS_RDONLY)) {
 123                 nilfs_set_error(sb);
 124
 125                 if (nilfs_test_opt(nilfs, 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(nilfs, 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         struct va_format vaf;
 140         va_list args;
 141
 142         va_start(args, fmt);
 143
 144         vaf.fmt = fmt;
 145         vaf.va = &args;
 146
 147         printk(KERN_WARNING "NILFS warning (device %s): %s: %pV\n",
 148                sb->s_id, function, &vaf);
 149
 150         va_end(args);
 151 }
 152
 153
 154 struct inode *nilfs_alloc_inode(struct super_block *sb)
 155 {
 156         struct nilfs_inode_info *ii;
 157
 158         ii = kmem_cache_alloc(nilfs_inode_cachep, GFP_NOFS);
 159         if (!ii)
 160                 return NULL;
 161         ii->i_bh = NULL;
 162         ii->i_state = 0;
 163         ii->i_cno = 0;
 164         ii->vfs_inode.i_version = 1;
 165         nilfs_mapping_init(&ii->i_btnode_cache, &ii->vfs_inode);
 166         return &ii->vfs_inode;
 167 }
 168
 169 static void nilfs_i_callback(struct rcu_head *head)
 170 {
 171         struct inode *inode = container_of(head, struct inode, i_rcu);
 172
 173         if (nilfs_is_metadata_file_inode(inode))
 174                 nilfs_mdt_destroy(inode);
 175
 176         kmem_cache_free(nilfs_inode_cachep, NILFS_I(inode));
 177 }
 178
 179 void nilfs_destroy_inode(struct inode *inode)
 180 {
 181         call_rcu(&inode->i_rcu, nilfs_i_callback);
 182 }
 183
 184 static int nilfs_sync_super(struct super_block *sb, int flag)
 185 {
 186         struct the_nilfs *nilfs = sb->s_fs_info;
 187         int err;
 188
 189  retry:
 190         set_buffer_dirty(nilfs->ns_sbh[0]);
 191         if (nilfs_test_opt(nilfs, BARRIER)) {
 192                 err = __sync_dirty_buffer(nilfs->ns_sbh[0],
 193                                           WRITE_SYNC | WRITE_FLUSH_FUA);
 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 super_block *sb,
 259                                                int flip)
 260 {
 261         struct the_nilfs *nilfs = sb->s_fs_info;
 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                                sb->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 super_block *sb, int flag)
 286 {
 287         struct the_nilfs *nilfs = sb->s_fs_info;
 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         nilfs->ns_flushed_device = 1;
 308         /* make sure store to ns_flushed_device cannot be reordered */
 309         smp_wmb();
 310         return nilfs_sync_super(sb, flag);
 311 }
 312
 313 /**
 314  * nilfs_cleanup_super() - write filesystem state for cleanup
 315  * @sb: super block instance to be unmounted or degraded to read-only
 316  *
 317  * This function restores state flags in the on-disk super block.
 318  * This will set "clean" flag (i.e. NILFS_VALID_FS) unless the
 319  * filesystem was not clean previously.
 320  */
 321 int nilfs_cleanup_super(struct super_block *sb)
 322 {
 323         struct the_nilfs *nilfs = sb->s_fs_info;
 324         struct nilfs_super_block **sbp;
 325         int flag = NILFS_SB_COMMIT;
 326         int ret = -EIO;
 327
 328         sbp = nilfs_prepare_super(sb, 0);
 329         if (sbp) {
 330                 sbp[0]->s_state = cpu_to_le16(nilfs->ns_mount_state);
 331                 nilfs_set_log_cursor(sbp[0], nilfs);
 332                 if (sbp[1] && sbp[0]->s_last_cno == sbp[1]->s_last_cno) {
 333                         /*
 334                          * make the "clean" flag also to the opposite
 335                          * super block if both super blocks point to
 336                          * the same checkpoint.
 337                          */
 338                         sbp[1]->s_state = sbp[0]->s_state;
 339                         flag = NILFS_SB_COMMIT_ALL;
 340                 }
 341                 ret = nilfs_commit_super(sb, flag);
 342         }
 343         return ret;
 344 }
 345
 346 /**
 347  * nilfs_move_2nd_super - relocate secondary super block
 348  * @sb: super block instance
 349  * @sb2off: new offset of the secondary super block (in bytes)
 350  */
 351 static int nilfs_move_2nd_super(struct super_block *sb, loff_t sb2off)
 352 {
 353         struct the_nilfs *nilfs = sb->s_fs_info;
 354         struct buffer_head *nsbh;
 355         struct nilfs_super_block *nsbp;
 356         sector_t blocknr, newblocknr;
 357         unsigned long offset;
 358         int sb2i;  /* array index of the secondary superblock */
 359         int ret = 0;
 360
 361         /* nilfs->ns_sem must be locked by the caller. */
 362         if (nilfs->ns_sbh[1] &&
 363             nilfs->ns_sbh[1]->b_blocknr > nilfs->ns_first_data_block) {
 364                 sb2i = 1;
 365                 blocknr = nilfs->ns_sbh[1]->b_blocknr;
 366         } else if (nilfs->ns_sbh[0]->b_blocknr > nilfs->ns_first_data_block) {
 367                 sb2i = 0;
 368                 blocknr = nilfs->ns_sbh[0]->b_blocknr;
 369         } else {
 370                 sb2i = -1;
 371                 blocknr = 0;
 372         }
 373         if (sb2i >= 0 && (u64)blocknr << nilfs->ns_blocksize_bits == sb2off)
 374                 goto out;  /* super block location is unchanged */
 375
 376         /* Get new super block buffer */
 377         newblocknr = sb2off >> nilfs->ns_blocksize_bits;
 378         offset = sb2off & (nilfs->ns_blocksize - 1);
 379         nsbh = sb_getblk(sb, newblocknr);
 380         if (!nsbh) {
 381                 printk(KERN_WARNING
 382                        "NILFS warning: unable to move secondary superblock "
 383                        "to block %llu\n", (unsigned long long)newblocknr);
 384                 ret = -EIO;
 385                 goto out;
 386         }
 387         nsbp = (void *)nsbh->b_data + offset;
 388         memset(nsbp, 0, nilfs->ns_blocksize);
 389
 390         if (sb2i >= 0) {
 391                 memcpy(nsbp, nilfs->ns_sbp[sb2i], nilfs->ns_sbsize);
 392                 brelse(nilfs->ns_sbh[sb2i]);
 393                 nilfs->ns_sbh[sb2i] = nsbh;
 394                 nilfs->ns_sbp[sb2i] = nsbp;
 395         } else if (nilfs->ns_sbh[0]->b_blocknr < nilfs->ns_first_data_block) {
 396                 /* secondary super block will be restored to index 1 */
 397                 nilfs->ns_sbh[1] = nsbh;
 398                 nilfs->ns_sbp[1] = nsbp;
 399         } else {
 400                 brelse(nsbh);
 401         }
 402 out:
 403         return ret;
 404 }
 405
 406 /**
 407  * nilfs_resize_fs - resize the filesystem
 408  * @sb: super block instance
 409  * @newsize: new size of the filesystem (in bytes)
 410  */
 411 int nilfs_resize_fs(struct super_block *sb, __u64 newsize)
 412 {
 413         struct the_nilfs *nilfs = sb->s_fs_info;
 414         struct nilfs_super_block **sbp;
 415         __u64 devsize, newnsegs;
 416         loff_t sb2off;
 417         int ret;
 418
 419         ret = -ERANGE;
 420         devsize = i_size_read(sb->s_bdev->bd_inode);
 421         if (newsize > devsize)
 422                 goto out;
 423
 424         /*
 425          * Write lock is required to protect some functions depending
 426          * on the number of segments, the number of reserved segments,
 427          * and so forth.
 428          */
 429         down_write(&nilfs->ns_segctor_sem);
 430
 431         sb2off = NILFS_SB2_OFFSET_BYTES(newsize);
 432         newnsegs = sb2off >> nilfs->ns_blocksize_bits;
 433         do_div(newnsegs, nilfs->ns_blocks_per_segment);
 434
 435         ret = nilfs_sufile_resize(nilfs->ns_sufile, newnsegs);
 436         up_write(&nilfs->ns_segctor_sem);
 437         if (ret < 0)
 438                 goto out;
 439
 440         ret = nilfs_construct_segment(sb);
 441         if (ret < 0)
 442                 goto out;
 443
 444         down_write(&nilfs->ns_sem);
 445         nilfs_move_2nd_super(sb, sb2off);
 446         ret = -EIO;
 447         sbp = nilfs_prepare_super(sb, 0);
 448         if (likely(sbp)) {
 449                 nilfs_set_log_cursor(sbp[0], nilfs);
 450                 /*
 451                  * Drop NILFS_RESIZE_FS flag for compatibility with
 452                  * mount-time resize which may be implemented in a
 453                  * future release.
 454                  */
 455                 sbp[0]->s_state = cpu_to_le16(le16_to_cpu(sbp[0]->s_state) &
 456                                               ~NILFS_RESIZE_FS);
 457                 sbp[0]->s_dev_size = cpu_to_le64(newsize);
 458                 sbp[0]->s_nsegments = cpu_to_le64(nilfs->ns_nsegments);
 459                 if (sbp[1])
 460                         memcpy(sbp[1], sbp[0], nilfs->ns_sbsize);
 461                 ret = nilfs_commit_super(sb, NILFS_SB_COMMIT_ALL);
 462         }
 463         up_write(&nilfs->ns_sem);
 464
 465         /*
 466          * Reset the range of allocatable segments last.  This order
 467          * is important in the case of expansion because the secondary
 468          * superblock must be protected from log write until migration
 469          * completes.
 470          */
 471         if (!ret)
 472                 nilfs_sufile_set_alloc_range(nilfs->ns_sufile, 0, newnsegs - 1);
 473 out:
 474         return ret;
 475 }
 476
 477 static void nilfs_put_super(struct super_block *sb)
 478 {
 479         struct the_nilfs *nilfs = sb->s_fs_info;
 480
 481         nilfs_detach_log_writer(sb);
 482
 483         if (!(sb->s_flags & MS_RDONLY)) {
 484                 down_write(&nilfs->ns_sem);
 485                 nilfs_cleanup_super(sb);
 486                 up_write(&nilfs->ns_sem);
 487         }
 488
 489         iput(nilfs->ns_sufile);
 490         iput(nilfs->ns_cpfile);
 491         iput(nilfs->ns_dat);
 492
 493         destroy_nilfs(nilfs);
 494         sb->s_fs_info = NULL;
 495 }
 496
 497 static int nilfs_sync_fs(struct super_block *sb, int wait)
 498 {
 499         struct the_nilfs *nilfs = sb->s_fs_info;
 500         struct nilfs_super_block **sbp;
 501         int err = 0;
 502
 503         /* This function is called when super block should be written back */
 504         if (wait)
 505                 err = nilfs_construct_segment(sb);
 506
 507         down_write(&nilfs->ns_sem);
 508         if (nilfs_sb_dirty(nilfs)) {
 509                 sbp = nilfs_prepare_super(sb, nilfs_sb_will_flip(nilfs));
 510                 if (likely(sbp)) {
 511                         nilfs_set_log_cursor(sbp[0], nilfs);
 512                         nilfs_commit_super(sb, NILFS_SB_COMMIT);
 513                 }
 514         }
 515         up_write(&nilfs->ns_sem);
 516
 517         if (!err)
 518                 err = nilfs_flush_device(nilfs);
 519
 520         return err;
 521 }
 522
 523 int nilfs_attach_checkpoint(struct super_block *sb, __u64 cno, int curr_mnt,
 524                             struct nilfs_root **rootp)
 525 {
 526         struct the_nilfs *nilfs = sb->s_fs_info;
 527         struct nilfs_root *root;
 528         struct nilfs_checkpoint *raw_cp;
 529         struct buffer_head *bh_cp;
 530         int err = -ENOMEM;
 531
 532         root = nilfs_find_or_create_root(
 533                 nilfs, curr_mnt ? NILFS_CPTREE_CURRENT_CNO : cno);
 534         if (!root)
 535                 return err;
 536
 537         if (root->ifile)
 538                 goto reuse; /* already attached checkpoint */
 539
 540         down_read(&nilfs->ns_segctor_sem);
 541         err = nilfs_cpfile_get_checkpoint(nilfs->ns_cpfile, cno, 0, &raw_cp,
 542                                           &bh_cp);
 543         up_read(&nilfs->ns_segctor_sem);
 544         if (unlikely(err)) {
 545                 if (err == -ENOENT || err == -EINVAL) {
 546                         printk(KERN_ERR
 547                                "NILFS: Invalid checkpoint "
 548                                "(checkpoint number=%llu)\n",
 549                                (unsigned long long)cno);
 550                         err = -EINVAL;
 551                 }
 552                 goto failed;
 553         }
 554
 555         err = nilfs_ifile_read(sb, root, nilfs->ns_inode_size,
 556                                &raw_cp->cp_ifile_inode, &root->ifile);
 557         if (err)
 558                 goto failed_bh;
 559
 560         atomic64_set(&root->inodes_count,
 561                         le64_to_cpu(raw_cp->cp_inodes_count));
 562         atomic64_set(&root->blocks_count,
 563                         le64_to_cpu(raw_cp->cp_blocks_count));
 564
 565         nilfs_cpfile_put_checkpoint(nilfs->ns_cpfile, cno, bh_cp);
 566
 567  reuse:
 568         *rootp = root;
 569         return 0;
 570
 571  failed_bh:
 572         nilfs_cpfile_put_checkpoint(nilfs->ns_cpfile, cno, bh_cp);
 573  failed:
 574         nilfs_put_root(root);
 575
 576         return err;
 577 }
 578
 579 static int nilfs_freeze(struct super_block *sb)
 580 {
 581         struct the_nilfs *nilfs = sb->s_fs_info;
 582         int err;
 583
 584         if (sb->s_flags & MS_RDONLY)
 585                 return 0;
 586
 587         /* Mark super block clean */
 588         down_write(&nilfs->ns_sem);
 589         err = nilfs_cleanup_super(sb);
 590         up_write(&nilfs->ns_sem);
 591         return err;
 592 }
 593
 594 static int nilfs_unfreeze(struct super_block *sb)
 595 {
 596         struct the_nilfs *nilfs = sb->s_fs_info;
 597
 598         if (sb->s_flags & MS_RDONLY)
 599                 return 0;
 600
 601         down_write(&nilfs->ns_sem);
 602         nilfs_setup_super(sb, false);
 603         up_write(&nilfs->ns_sem);
 604         return 0;
 605 }
 606
 607 static int nilfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 608 {
 609         struct super_block *sb = dentry->d_sb;
 610         struct nilfs_root *root = NILFS_I(d_inode(dentry))->i_root;
 611         struct the_nilfs *nilfs = root->nilfs;
 612         u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
 613         unsigned long long blocks;
 614         unsigned long overhead;
 615         unsigned long nrsvblocks;
 616         sector_t nfreeblocks;
 617         u64 nmaxinodes, nfreeinodes;
 618         int err;
 619
 620         /*
 621          * Compute all of the segment blocks
 622          *
 623          * The blocks before first segment and after last segment
 624          * are excluded.
 625          */
 626         blocks = nilfs->ns_blocks_per_segment * nilfs->ns_nsegments
 627                 - nilfs->ns_first_data_block;
 628         nrsvblocks = nilfs->ns_nrsvsegs * nilfs->ns_blocks_per_segment;
 629
 630         /*
 631          * Compute the overhead
 632          *
 633          * When distributing meta data blocks outside segment structure,
 634          * We must count them as the overhead.
 635          */
 636         overhead = 0;
 637
 638         err = nilfs_count_free_blocks(nilfs, &nfreeblocks);
 639         if (unlikely(err))
 640                 return err;
 641
 642         err = nilfs_ifile_count_free_inodes(root->ifile,
 643                                             &nmaxinodes, &nfreeinodes);
 644         if (unlikely(err)) {
 645                 printk(KERN_WARNING
 646                         "NILFS warning: fail to count free inodes: err %d.\n",
 647                         err);
 648                 if (err == -ERANGE) {
 649                         /*
 650                          * If nilfs_palloc_count_max_entries() returns
 651                          * -ERANGE error code then we simply treat
 652                          * curent inodes count as maximum possible and
 653                          * zero as free inodes value.
 654                          */
 655                         nmaxinodes = atomic64_read(&root->inodes_count);
 656                         nfreeinodes = 0;
 657                         err = 0;
 658                 } else
 659                         return err;
 660         }
 661
 662         buf->f_type = NILFS_SUPER_MAGIC;
 663         buf->f_bsize = sb->s_blocksize;
 664         buf->f_blocks = blocks - overhead;
 665         buf->f_bfree = nfreeblocks;
 666         buf->f_bavail = (buf->f_bfree >= nrsvblocks) ?
 667                 (buf->f_bfree - nrsvblocks) : 0;
 668         buf->f_files = nmaxinodes;
 669         buf->f_ffree = nfreeinodes;
 670         buf->f_namelen = NILFS_NAME_LEN;
 671         buf->f_fsid.val[0] = (u32)id;
 672         buf->f_fsid.val[1] = (u32)(id >> 32);
 673
 674         return 0;
 675 }
 676
 677 static int nilfs_show_options(struct seq_file *seq, struct dentry *dentry)
 678 {
 679         struct super_block *sb = dentry->d_sb;
 680         struct the_nilfs *nilfs = sb->s_fs_info;
 681         struct nilfs_root *root = NILFS_I(d_inode(dentry))->i_root;
 682
 683         if (!nilfs_test_opt(nilfs, BARRIER))
 684                 seq_puts(seq, ",nobarrier");
 685         if (root->cno != NILFS_CPTREE_CURRENT_CNO)
 686                 seq_printf(seq, ",cp=%llu", (unsigned long long)root->cno);
 687         if (nilfs_test_opt(nilfs, ERRORS_PANIC))
 688                 seq_puts(seq, ",errors=panic");
 689         if (nilfs_test_opt(nilfs, ERRORS_CONT))
 690                 seq_puts(seq, ",errors=continue");
 691         if (nilfs_test_opt(nilfs, STRICT_ORDER))
 692                 seq_puts(seq, ",order=strict");
 693         if (nilfs_test_opt(nilfs, NORECOVERY))
 694                 seq_puts(seq, ",norecovery");
 695         if (nilfs_test_opt(nilfs, DISCARD))
 696                 seq_puts(seq, ",discard");
 697
 698         return 0;
 699 }
 700
 701 static const struct super_operations nilfs_sops = {
 702         .alloc_inode    = nilfs_alloc_inode,
 703         .destroy_inode  = nilfs_destroy_inode,
 704         .dirty_inode    = nilfs_dirty_inode,
 705         .evict_inode    = nilfs_evict_inode,
 706         .put_super      = nilfs_put_super,
 707         .sync_fs        = nilfs_sync_fs,
 708         .freeze_fs      = nilfs_freeze,
 709         .unfreeze_fs    = nilfs_unfreeze,
 710         .statfs         = nilfs_statfs,
 711         .remount_fs     = nilfs_remount,
 712         .show_options = nilfs_show_options
 713 };
 714
 715 enum {
 716         Opt_err_cont, Opt_err_panic, Opt_err_ro,
 717         Opt_barrier, Opt_nobarrier, Opt_snapshot, Opt_order, Opt_norecovery,
 718         Opt_discard, Opt_nodiscard, Opt_err,
 719 };
 720
 721 static match_table_t tokens = {
 722         {Opt_err_cont, "errors=continue"},
 723         {Opt_err_panic, "errors=panic"},
 724         {Opt_err_ro, "errors=remount-ro"},
 725         {Opt_barrier, "barrier"},
 726         {Opt_nobarrier, "nobarrier"},
 727         {Opt_snapshot, "cp=%u"},
 728         {Opt_order, "order=%s"},
 729         {Opt_norecovery, "norecovery"},
 730         {Opt_discard, "discard"},
 731         {Opt_nodiscard, "nodiscard"},
 732         {Opt_err, NULL}
 733 };
 734
 735 static int parse_options(char *options, struct super_block *sb, int is_remount)
 736 {
 737         struct the_nilfs *nilfs = sb->s_fs_info;
 738         char *p;
 739         substring_t args[MAX_OPT_ARGS];
 740
 741         if (!options)
 742                 return 1;
 743
 744         while ((p = strsep(&options, ",")) != NULL) {
 745                 int token;
 746
 747                 if (!*p)
 748                         continue;
 749
 750                 token = match_token(p, tokens, args);
 751                 switch (token) {
 752                 case Opt_barrier:
 753                         nilfs_set_opt(nilfs, BARRIER);
 754                         break;
 755                 case Opt_nobarrier:
 756                         nilfs_clear_opt(nilfs, BARRIER);
 757                         break;
 758                 case Opt_order:
 759                         if (strcmp(args[0].from, "relaxed") == 0)
 760                                 /* Ordered data semantics */
 761                                 nilfs_clear_opt(nilfs, STRICT_ORDER);
 762                         else if (strcmp(args[0].from, "strict") == 0)
 763                                 /* Strict in-order semantics */
 764                                 nilfs_set_opt(nilfs, STRICT_ORDER);
 765                         else
 766                                 return 0;
 767                         break;
 768                 case Opt_err_panic:
 769                         nilfs_write_opt(nilfs, ERROR_MODE, ERRORS_PANIC);
 770                         break;
 771                 case Opt_err_ro:
 772                         nilfs_write_opt(nilfs, ERROR_MODE, ERRORS_RO);
 773                         break;
 774                 case Opt_err_cont:
 775                         nilfs_write_opt(nilfs, ERROR_MODE, ERRORS_CONT);
 776                         break;
 777                 case Opt_snapshot:
 778                         if (is_remount) {
 779                                 printk(KERN_ERR
 780                                        "NILFS: \"%s\" option is invalid "
 781                                        "for remount.\n", p);
 782                                 return 0;
 783                         }
 784                         break;
 785                 case Opt_norecovery:
 786                         nilfs_set_opt(nilfs, NORECOVERY);
 787                         break;
 788                 case Opt_discard:
 789                         nilfs_set_opt(nilfs, DISCARD);
 790                         break;
 791                 case Opt_nodiscard:
 792                         nilfs_clear_opt(nilfs, DISCARD);
 793                         break;
 794                 default:
 795                         printk(KERN_ERR
 796                                "NILFS: Unrecognized mount option \"%s\"\n", p);
 797                         return 0;
 798                 }
 799         }
 800         return 1;
 801 }
 802
 803 static inline void
 804 nilfs_set_default_options(struct super_block *sb,
 805                           struct nilfs_super_block *sbp)
 806 {
 807         struct the_nilfs *nilfs = sb->s_fs_info;
 808
 809         nilfs->ns_mount_opt =
 810                 NILFS_MOUNT_ERRORS_RO | NILFS_MOUNT_BARRIER;
 811 }
 812
 813 static int nilfs_setup_super(struct super_block *sb, int is_mount)
 814 {
 815         struct the_nilfs *nilfs = sb->s_fs_info;
 816         struct nilfs_super_block **sbp;
 817         int max_mnt_count;
 818         int mnt_count;
 819
 820         /* nilfs->ns_sem must be locked by the caller. */
 821         sbp = nilfs_prepare_super(sb, 0);
 822         if (!sbp)
 823                 return -EIO;
 824
 825         if (!is_mount)
 826                 goto skip_mount_setup;
 827
 828         max_mnt_count = le16_to_cpu(sbp[0]->s_max_mnt_count);
 829         mnt_count = le16_to_cpu(sbp[0]->s_mnt_count);
 830
 831         if (nilfs->ns_mount_state & NILFS_ERROR_FS) {
 832                 printk(KERN_WARNING
 833                        "NILFS warning: mounting fs with errors\n");
 834 #if 0
 835         } else if (max_mnt_count >= 0 && mnt_count >= max_mnt_count) {
 836                 printk(KERN_WARNING
 837                        "NILFS warning: maximal mount count reached\n");
 838 #endif
 839         }
 840         if (!max_mnt_count)
 841                 sbp[0]->s_max_mnt_count = cpu_to_le16(NILFS_DFL_MAX_MNT_COUNT);
 842
 843         sbp[0]->s_mnt_count = cpu_to_le16(mnt_count + 1);
 844         sbp[0]->s_mtime = cpu_to_le64(get_seconds());
 845
 846 skip_mount_setup:
 847         sbp[0]->s_state =
 848                 cpu_to_le16(le16_to_cpu(sbp[0]->s_state) & ~NILFS_VALID_FS);
 849         /* synchronize sbp[1] with sbp[0] */
 850         if (sbp[1])
 851                 memcpy(sbp[1], sbp[0], nilfs->ns_sbsize);
 852         return nilfs_commit_super(sb, NILFS_SB_COMMIT_ALL);
 853 }
 854
 855 struct nilfs_super_block *nilfs_read_super_block(struct super_block *sb,
 856                                                  u64 pos, int blocksize,
 857                                                  struct buffer_head **pbh)
 858 {
 859         unsigned long long sb_index = pos;
 860         unsigned long offset;
 861
 862         offset = do_div(sb_index, blocksize);
 863         *pbh = sb_bread(sb, sb_index);
 864         if (!*pbh)
 865                 return NULL;
 866         return (struct nilfs_super_block *)((char *)(*pbh)->b_data + offset);
 867 }
 868
 869 int nilfs_store_magic_and_option(struct super_block *sb,
 870                                  struct nilfs_super_block *sbp,
 871                                  char *data)
 872 {
 873         struct the_nilfs *nilfs = sb->s_fs_info;
 874
 875         sb->s_magic = le16_to_cpu(sbp->s_magic);
 876
 877         /* FS independent flags */
 878 #ifdef NILFS_ATIME_DISABLE
 879         sb->s_flags |= MS_NOATIME;
 880 #endif
 881
 882         nilfs_set_default_options(sb, sbp);
 883
 884         nilfs->ns_resuid = le16_to_cpu(sbp->s_def_resuid);
 885         nilfs->ns_resgid = le16_to_cpu(sbp->s_def_resgid);
 886         nilfs->ns_interval = le32_to_cpu(sbp->s_c_interval);
 887         nilfs->ns_watermark = le32_to_cpu(sbp->s_c_block_max);
 888
 889         return !parse_options(data, sb, 0) ? -EINVAL : 0;
 890 }
 891
 892 int nilfs_check_feature_compatibility(struct super_block *sb,
 893                                       struct nilfs_super_block *sbp)
 894 {
 895         __u64 features;
 896
 897         features = le64_to_cpu(sbp->s_feature_incompat) &
 898                 ~NILFS_FEATURE_INCOMPAT_SUPP;
 899         if (features) {
 900                 printk(KERN_ERR "NILFS: couldn't mount because of unsupported "
 901                        "optional features (%llx)\n",
 902                        (unsigned long long)features);
 903                 return -EINVAL;
 904         }
 905         features = le64_to_cpu(sbp->s_feature_compat_ro) &
 906                 ~NILFS_FEATURE_COMPAT_RO_SUPP;
 907         if (!(sb->s_flags & MS_RDONLY) && features) {
 908                 printk(KERN_ERR "NILFS: couldn't mount RDWR because of "
 909                        "unsupported optional features (%llx)\n",
 910                        (unsigned long long)features);
 911                 return -EINVAL;
 912         }
 913         return 0;
 914 }
 915
 916 static int nilfs_get_root_dentry(struct super_block *sb,
 917                                  struct nilfs_root *root,
 918                                  struct dentry **root_dentry)
 919 {
 920         struct inode *inode;
 921         struct dentry *dentry;
 922         int ret = 0;
 923
 924         inode = nilfs_iget(sb, root, NILFS_ROOT_INO);
 925         if (IS_ERR(inode)) {
 926                 printk(KERN_ERR "NILFS: get root inode failed\n");
 927                 ret = PTR_ERR(inode);
 928                 goto out;
 929         }
 930         if (!S_ISDIR(inode->i_mode) || !inode->i_blocks || !inode->i_size) {
 931                 iput(inode);
 932                 printk(KERN_ERR "NILFS: corrupt root inode.\n");
 933                 ret = -EINVAL;
 934                 goto out;
 935         }
 936
 937         if (root->cno == NILFS_CPTREE_CURRENT_CNO) {
 938                 dentry = d_find_alias(inode);
 939                 if (!dentry) {
 940                         dentry = d_make_root(inode);
 941                         if (!dentry) {
 942                                 ret = -ENOMEM;
 943                                 goto failed_dentry;
 944                         }
 945                 } else {
 946                         iput(inode);
 947                 }
 948         } else {
 949                 dentry = d_obtain_root(inode);
 950                 if (IS_ERR(dentry)) {
 951                         ret = PTR_ERR(dentry);
 952                         goto failed_dentry;
 953                 }
 954         }
 955         *root_dentry = dentry;
 956  out:
 957         return ret;
 958
 959  failed_dentry:
 960         printk(KERN_ERR "NILFS: get root dentry failed\n");
 961         goto out;
 962 }
 963
 964 static int nilfs_attach_snapshot(struct super_block *s, __u64 cno,
 965                                  struct dentry **root_dentry)
 966 {
 967         struct the_nilfs *nilfs = s->s_fs_info;
 968         struct nilfs_root *root;
 969         int ret;
 970
 971         mutex_lock(&nilfs->ns_snapshot_mount_mutex);
 972
 973         down_read(&nilfs->ns_segctor_sem);
 974         ret = nilfs_cpfile_is_snapshot(nilfs->ns_cpfile, cno);
 975         up_read(&nilfs->ns_segctor_sem);
 976         if (ret < 0) {
 977                 ret = (ret == -ENOENT) ? -EINVAL : ret;
 978                 goto out;
 979         } else if (!ret) {
 980                 printk(KERN_ERR "NILFS: The specified checkpoint is "
 981                        "not a snapshot (checkpoint number=%llu).\n",
 982                        (unsigned long long)cno);
 983                 ret = -EINVAL;
 984                 goto out;
 985         }
 986
 987         ret = nilfs_attach_checkpoint(s, cno, false, &root);
 988         if (ret) {
 989                 printk(KERN_ERR "NILFS: error loading snapshot "
 990                        "(checkpoint number=%llu).\n",
 991                (unsigned long long)cno);
 992                 goto out;
 993         }
 994         ret = nilfs_get_root_dentry(s, root, root_dentry);
 995         nilfs_put_root(root);
 996  out:
 997         mutex_unlock(&nilfs->ns_snapshot_mount_mutex);
 998         return ret;
 999 }
1000
1001 /**
1002  * nilfs_tree_is_busy() - try to shrink dentries of a checkpoint
1003  * @root_dentry: root dentry of the tree to be shrunk
1004  *
1005  * This function returns true if the tree was in-use.
1006  */
1007 static bool nilfs_tree_is_busy(struct dentry *root_dentry)
1008 {
1009         shrink_dcache_parent(root_dentry);
1010         return d_count(root_dentry) > 1;
1011 }
1012
1013 int nilfs_checkpoint_is_mounted(struct super_block *sb, __u64 cno)
1014 {
1015         struct the_nilfs *nilfs = sb->s_fs_info;
1016         struct nilfs_root *root;
1017         struct inode *inode;
1018         struct dentry *dentry;
1019         int ret;
1020
1021         if (cno > nilfs->ns_cno)
1022                 return false;
1023
1024         if (cno >= nilfs_last_cno(nilfs))
1025                 return true;    /* protect recent checkpoints */
1026
1027         ret = false;
1028         root = nilfs_lookup_root(nilfs, cno);
1029         if (root) {
1030                 inode = nilfs_ilookup(sb, root, NILFS_ROOT_INO);
1031                 if (inode) {
1032                         dentry = d_find_alias(inode);
1033                         if (dentry) {
1034                                 ret = nilfs_tree_is_busy(dentry);
1035                                 dput(dentry);
1036                         }
1037                         iput(inode);
1038                 }
1039                 nilfs_put_root(root);
1040         }
1041         return ret;
1042 }
1043
1044 /**
1045  * nilfs_fill_super() - initialize a super block instance
1046  * @sb: super_block
1047  * @data: mount options
1048  * @silent: silent mode flag
1049  *
1050  * This function is called exclusively by nilfs->ns_mount_mutex.
1051  * So, the recovery process is protected from other simultaneous mounts.
1052  */
1053 static int
1054 nilfs_fill_super(struct super_block *sb, void *data, int silent)
1055 {
1056         struct the_nilfs *nilfs;
1057         struct nilfs_root *fsroot;
1058         __u64 cno;
1059         int err;
1060
1061         nilfs = alloc_nilfs(sb->s_bdev);
1062         if (!nilfs)
1063                 return -ENOMEM;
1064
1065         sb->s_fs_info = nilfs;
1066
1067         err = init_nilfs(nilfs, sb, (char *)data);
1068         if (err)
1069                 goto failed_nilfs;
1070
1071         sb->s_op = &nilfs_sops;
1072         sb->s_export_op = &nilfs_export_ops;
1073         sb->s_root = NULL;
1074         sb->s_time_gran = 1;
1075         sb->s_max_links = NILFS_LINK_MAX;
1076
1077         sb->s_bdi = &bdev_get_queue(sb->s_bdev)->backing_dev_info;
1078
1079         err = load_nilfs(nilfs, sb);
1080         if (err)
1081                 goto failed_nilfs;
1082
1083         cno = nilfs_last_cno(nilfs);
1084         err = nilfs_attach_checkpoint(sb, cno, true, &fsroot);
1085         if (err) {
1086                 printk(KERN_ERR "NILFS: error loading last checkpoint "
1087                        "(checkpoint number=%llu).\n", (unsigned long long)cno);
1088                 goto failed_unload;
1089         }
1090
1091         if (!(sb->s_flags & MS_RDONLY)) {
1092                 err = nilfs_attach_log_writer(sb, fsroot);
1093                 if (err)
1094                         goto failed_checkpoint;
1095         }
1096
1097         err = nilfs_get_root_dentry(sb, fsroot, &sb->s_root);
1098         if (err)
1099                 goto failed_segctor;
1100
1101         nilfs_put_root(fsroot);
1102
1103         if (!(sb->s_flags & MS_RDONLY)) {
1104                 down_write(&nilfs->ns_sem);
1105                 nilfs_setup_super(sb, true);
1106                 up_write(&nilfs->ns_sem);
1107         }
1108
1109         return 0;
1110
1111  failed_segctor:
1112         nilfs_detach_log_writer(sb);
1113
1114  failed_checkpoint:
1115         nilfs_put_root(fsroot);
1116
1117  failed_unload:
1118         iput(nilfs->ns_sufile);
1119         iput(nilfs->ns_cpfile);
1120         iput(nilfs->ns_dat);
1121
1122  failed_nilfs:
1123         destroy_nilfs(nilfs);
1124         return err;
1125 }
1126
1127 static int nilfs_remount(struct super_block *sb, int *flags, char *data)
1128 {
1129         struct the_nilfs *nilfs = sb->s_fs_info;
1130         unsigned long old_sb_flags;
1131         unsigned long old_mount_opt;
1132         int err;
1133
1134         sync_filesystem(sb);
1135         old_sb_flags = sb->s_flags;
1136         old_mount_opt = nilfs->ns_mount_opt;
1137
1138         if (!parse_options(data, sb, 1)) {
1139                 err = -EINVAL;
1140                 goto restore_opts;
1141         }
1142         sb->s_flags = (sb->s_flags & ~MS_POSIXACL);
1143
1144         err = -EINVAL;
1145
1146         if (!nilfs_valid_fs(nilfs)) {
1147                 printk(KERN_WARNING "NILFS (device %s): couldn't "
1148                        "remount because the filesystem is in an "
1149                        "incomplete recovery state.\n", sb->s_id);
1150                 goto restore_opts;
1151         }
1152
1153         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
1154                 goto out;
1155         if (*flags & MS_RDONLY) {
1156                 /* Shutting down log writer */
1157                 nilfs_detach_log_writer(sb);
1158                 sb->s_flags |= MS_RDONLY;
1159
1160                 /*
1161                  * Remounting a valid RW partition RDONLY, so set
1162                  * the RDONLY flag and then mark the partition as valid again.
1163                  */
1164                 down_write(&nilfs->ns_sem);
1165                 nilfs_cleanup_super(sb);
1166                 up_write(&nilfs->ns_sem);
1167         } else {
1168                 __u64 features;
1169                 struct nilfs_root *root;
1170
1171                 /*
1172                  * Mounting a RDONLY partition read-write, so reread and
1173                  * store the current valid flag.  (It may have been changed
1174                  * by fsck since we originally mounted the partition.)
1175                  */
1176                 down_read(&nilfs->ns_sem);
1177                 features = le64_to_cpu(nilfs->ns_sbp[0]->s_feature_compat_ro) &
1178                         ~NILFS_FEATURE_COMPAT_RO_SUPP;
1179                 up_read(&nilfs->ns_sem);
1180                 if (features) {
1181                         printk(KERN_WARNING "NILFS (device %s): couldn't "
1182                                "remount RDWR because of unsupported optional "
1183                                "features (%llx)\n",
1184                                sb->s_id, (unsigned long long)features);
1185                         err = -EROFS;
1186                         goto restore_opts;
1187                 }
1188
1189                 sb->s_flags &= ~MS_RDONLY;
1190
1191                 root = NILFS_I(d_inode(sb->s_root))->i_root;
1192                 err = nilfs_attach_log_writer(sb, root);
1193                 if (err)
1194                         goto restore_opts;
1195
1196                 down_write(&nilfs->ns_sem);
1197                 nilfs_setup_super(sb, true);
1198                 up_write(&nilfs->ns_sem);
1199         }
1200  out:
1201         return 0;
1202
1203  restore_opts:
1204         sb->s_flags = old_sb_flags;
1205         nilfs->ns_mount_opt = old_mount_opt;
1206         return err;
1207 }
1208
1209 struct nilfs_super_data {
1210         struct block_device *bdev;
1211         __u64 cno;
1212         int flags;
1213 };
1214
1215 /**
1216  * nilfs_identify - pre-read mount options needed to identify mount instance
1217  * @data: mount options
1218  * @sd: nilfs_super_data
1219  */
1220 static int nilfs_identify(char *data, struct nilfs_super_data *sd)
1221 {
1222         char *p, *options = data;
1223         substring_t args[MAX_OPT_ARGS];
1224         int token;
1225         int ret = 0;
1226
1227         do {
1228                 p = strsep(&options, ",");
1229                 if (p != NULL && *p) {
1230                         token = match_token(p, tokens, args);
1231                         if (token == Opt_snapshot) {
1232                                 if (!(sd->flags & MS_RDONLY)) {
1233                                         ret++;
1234                                 } else {
1235                                         sd->cno = simple_strtoull(args[0].from,
1236                                                                   NULL, 0);
1237                                         /*
1238                                          * No need to see the end pointer;
1239                                          * match_token() has done syntax
1240                                          * checking.
1241                                          */
1242                                         if (sd->cno == 0)
1243                                                 ret++;
1244                                 }
1245                         }
1246                         if (ret)
1247                                 printk(KERN_ERR
1248                                        "NILFS: invalid mount option: %s\n", p);
1249                 }
1250                 if (!options)
1251                         break;
1252                 BUG_ON(options == data);
1253                 *(options - 1) = ',';
1254         } while (!ret);
1255         return ret;
1256 }
1257
1258 static int nilfs_set_bdev_super(struct super_block *s, void *data)
1259 {
1260         s->s_bdev = data;
1261         s->s_dev = s->s_bdev->bd_dev;
1262         return 0;
1263 }
1264
1265 static int nilfs_test_bdev_super(struct super_block *s, void *data)
1266 {
1267         return (void *)s->s_bdev == data;
1268 }
1269
1270 static struct dentry *
1271 nilfs_mount(struct file_system_type *fs_type, int flags,
1272              const char *dev_name, void *data)
1273 {
1274         struct nilfs_super_data sd;
1275         struct super_block *s;
1276         fmode_t mode = FMODE_READ | FMODE_EXCL;
1277         struct dentry *root_dentry;
1278         int err, s_new = false;
1279
1280         if (!(flags & MS_RDONLY))
1281                 mode |= FMODE_WRITE;
1282
1283         sd.bdev = blkdev_get_by_path(dev_name, mode, fs_type);
1284         if (IS_ERR(sd.bdev))
1285                 return ERR_CAST(sd.bdev);
1286
1287         sd.cno = 0;
1288         sd.flags = flags;
1289         if (nilfs_identify((char *)data, &sd)) {
1290                 err = -EINVAL;
1291                 goto failed;
1292         }
1293
1294         /*
1295          * once the super is inserted into the list by sget, s_umount
1296          * will protect the lockfs code from trying to start a snapshot
1297          * while we are mounting
1298          */
1299         mutex_lock(&sd.bdev->bd_fsfreeze_mutex);
1300         if (sd.bdev->bd_fsfreeze_count > 0) {
1301                 mutex_unlock(&sd.bdev->bd_fsfreeze_mutex);
1302                 err = -EBUSY;
1303                 goto failed;
1304         }
1305         s = sget(fs_type, nilfs_test_bdev_super, nilfs_set_bdev_super, flags,
1306                  sd.bdev);
1307         mutex_unlock(&sd.bdev->bd_fsfreeze_mutex);
1308         if (IS_ERR(s)) {
1309                 err = PTR_ERR(s);
1310                 goto failed;
1311         }
1312
1313         if (!s->s_root) {
1314                 s_new = true;
1315
1316                 /* New superblock instance created */
1317                 s->s_mode = mode;
1318                 snprintf(s->s_id, sizeof(s->s_id), "%pg", sd.bdev);
1319                 sb_set_blocksize(s, block_size(sd.bdev));
1320
1321                 err = nilfs_fill_super(s, data, flags & MS_SILENT ? 1 : 0);
1322                 if (err)
1323                         goto failed_super;
1324
1325                 s->s_flags |= MS_ACTIVE;
1326         } else if (!sd.cno) {
1327                 if (nilfs_tree_is_busy(s->s_root)) {
1328                         if ((flags ^ s->s_flags) & MS_RDONLY) {
1329                                 printk(KERN_ERR "NILFS: the device already "
1330                                        "has a %s mount.\n",
1331                                        (s->s_flags & MS_RDONLY) ?
1332                                        "read-only" : "read/write");
1333                                 err = -EBUSY;
1334                                 goto failed_super;
1335                         }
1336                 } else {
1337                         /*
1338                          * Try remount to setup mount states if the current
1339                          * tree is not mounted and only snapshots use this sb.
1340                          */
1341                         err = nilfs_remount(s, &flags, data);
1342                         if (err)
1343                                 goto failed_super;
1344                 }
1345         }
1346
1347         if (sd.cno) {
1348                 err = nilfs_attach_snapshot(s, sd.cno, &root_dentry);
1349                 if (err)
1350                         goto failed_super;
1351         } else {
1352                 root_dentry = dget(s->s_root);
1353         }
1354
1355         if (!s_new)
1356                 blkdev_put(sd.bdev, mode);
1357
1358         return root_dentry;
1359
1360  failed_super:
1361         deactivate_locked_super(s);
1362
1363  failed:
1364         if (!s_new)
1365                 blkdev_put(sd.bdev, mode);
1366         return ERR_PTR(err);
1367 }
1368
1369 struct file_system_type nilfs_fs_type = {
1370         .owner    = THIS_MODULE,
1371         .name     = "nilfs2",
1372         .mount    = nilfs_mount,
1373         .kill_sb  = kill_block_super,
1374         .fs_flags = FS_REQUIRES_DEV,
1375 };
1376 MODULE_ALIAS_FS("nilfs2");
1377
1378 static void nilfs_inode_init_once(void *obj)
1379 {
1380         struct nilfs_inode_info *ii = obj;
1381
1382         INIT_LIST_HEAD(&ii->i_dirty);
1383 #ifdef CONFIG_NILFS_XATTR
1384         init_rwsem(&ii->xattr_sem);
1385 #endif
1386         address_space_init_once(&ii->i_btnode_cache);
1387         ii->i_bmap = &ii->i_bmap_data;
1388         inode_init_once(&ii->vfs_inode);
1389 }
1390
1391 static void nilfs_segbuf_init_once(void *obj)
1392 {
1393         memset(obj, 0, sizeof(struct nilfs_segment_buffer));
1394 }
1395
1396 static void nilfs_destroy_cachep(void)
1397 {
1398         /*
1399          * Make sure all delayed rcu free inodes are flushed before we
1400          * destroy cache.
1401          */
1402         rcu_barrier();
1403
1404         kmem_cache_destroy(nilfs_inode_cachep);
1405         kmem_cache_destroy(nilfs_transaction_cachep);
1406         kmem_cache_destroy(nilfs_segbuf_cachep);
1407         kmem_cache_destroy(nilfs_btree_path_cache);
1408 }
1409
1410 static int __init nilfs_init_cachep(void)
1411 {
1412         nilfs_inode_cachep = kmem_cache_create("nilfs2_inode_cache",
1413                         sizeof(struct nilfs_inode_info), 0,
1414                         SLAB_RECLAIM_ACCOUNT|SLAB_ACCOUNT,
1415                         nilfs_inode_init_once);
1416         if (!nilfs_inode_cachep)
1417                 goto fail;
1418
1419         nilfs_transaction_cachep = kmem_cache_create("nilfs2_transaction_cache",
1420                         sizeof(struct nilfs_transaction_info), 0,
1421                         SLAB_RECLAIM_ACCOUNT, NULL);
1422         if (!nilfs_transaction_cachep)
1423                 goto fail;
1424
1425         nilfs_segbuf_cachep = kmem_cache_create("nilfs2_segbuf_cache",
1426                         sizeof(struct nilfs_segment_buffer), 0,
1427                         SLAB_RECLAIM_ACCOUNT, nilfs_segbuf_init_once);
1428         if (!nilfs_segbuf_cachep)
1429                 goto fail;
1430
1431         nilfs_btree_path_cache = kmem_cache_create("nilfs2_btree_path_cache",
1432                         sizeof(struct nilfs_btree_path) * NILFS_BTREE_LEVEL_MAX,
1433                         0, 0, NULL);
1434         if (!nilfs_btree_path_cache)
1435                 goto fail;
1436
1437         return 0;
1438
1439 fail:
1440         nilfs_destroy_cachep();
1441         return -ENOMEM;
1442 }
1443
1444 static int __init init_nilfs_fs(void)
1445 {
1446         int err;
1447
1448         err = nilfs_init_cachep();
1449         if (err)
1450                 goto fail;
1451
1452         err = nilfs_sysfs_init();
1453         if (err)
1454                 goto free_cachep;
1455
1456         err = register_filesystem(&nilfs_fs_type);
1457         if (err)
1458                 goto deinit_sysfs_entry;
1459
1460         printk(KERN_INFO "NILFS version 2 loaded\n");
1461         return 0;
1462
1463 deinit_sysfs_entry:
1464         nilfs_sysfs_exit();
1465 free_cachep:
1466         nilfs_destroy_cachep();
1467 fail:
1468         return err;
1469 }
1470
1471 static void __exit exit_nilfs_fs(void)
1472 {
1473         nilfs_destroy_cachep();
1474         nilfs_sysfs_exit();
1475         unregister_filesystem(&nilfs_fs_type);
1476 }
1477
1478 module_init(init_nilfs_fs)
1479 module_exit(exit_nilfs_fs)