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 <[email protected]>
  21  */
  22 /*
  23  *  linux/fs/ext2/super.c
  24  *
  25  * Copyright (C) 1992, 1993, 1994, 1995
  26  * Remy Card ([email protected])
  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 ([email protected]), 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/crc32.h>
  47 #include <linux/vfs.h>
  48 #include <linux/writeback.h>
  49 #include <linux/seq_file.h>
  50 #include <linux/mount.h>
  51 #include "nilfs.h"
  52 #include "export.h"
  53 #include "mdt.h"
  54 #include "alloc.h"
  55 #include "btree.h"
  56 #include "btnode.h"
  57 #include "page.h"
  58 #include "cpfile.h"
  59 #include "sufile.h" /* nilfs_sufile_resize(), nilfs_sufile_set_alloc_range() */
  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 super_block *sb, int is_mount);
  76 static int nilfs_remount(struct super_block *sb, int *flags, char *data);
  77
  78 static void nilfs_set_error(struct super_block *sb)
  79 {
  80         struct the_nilfs *nilfs = sb->s_fs_info;
  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(sb, 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(sb, 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 the_nilfs *nilfs = sb->s_fs_info;
 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(sb);
 128
 129                 if (nilfs_test_opt(nilfs, 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(nilfs, 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_mapping_init(&ii->i_btnode_cache, &ii->vfs_inode, 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         if (mdi) {
 179                 kfree(mdi->mi_bgl); /* kfree(NULL) is safe */
 180                 kfree(mdi);
 181         }
 182         kmem_cache_free(nilfs_inode_cachep, NILFS_I(inode));
 183 }
 184
 185 void nilfs_destroy_inode(struct inode *inode)
 186 {
 187         call_rcu(&inode->i_rcu, nilfs_i_callback);
 188 }
 189
 190 static int nilfs_sync_super(struct super_block *sb, int flag)
 191 {
 192         struct the_nilfs *nilfs = sb->s_fs_info;
 193         int err;
 194
 195  retry:
 196         set_buffer_dirty(nilfs->ns_sbh[0]);
 197         if (nilfs_test_opt(nilfs, BARRIER)) {
 198                 err = __sync_dirty_buffer(nilfs->ns_sbh[0],
 199                                           WRITE_SYNC | WRITE_FLUSH_FUA);
 200         } else {
 201                 err = sync_dirty_buffer(nilfs->ns_sbh[0]);
 202         }
 203
 204         if (unlikely(err)) {
 205                 printk(KERN_ERR
 206                        "NILFS: unable to write superblock (err=%d)\n", err);
 207                 if (err == -EIO && nilfs->ns_sbh[1]) {
 208                         /*
 209                          * sbp[0] points to newer log than sbp[1],
 210                          * so copy sbp[0] to sbp[1] to take over sbp[0].
 211                          */
 212                         memcpy(nilfs->ns_sbp[1], nilfs->ns_sbp[0],
 213                                nilfs->ns_sbsize);
 214                         nilfs_fall_back_super_block(nilfs);
 215                         goto retry;
 216                 }
 217         } else {
 218                 struct nilfs_super_block *sbp = nilfs->ns_sbp[0];
 219
 220                 nilfs->ns_sbwcount++;
 221
 222                 /*
 223                  * The latest segment becomes trailable from the position
 224                  * written in superblock.
 225                  */
 226                 clear_nilfs_discontinued(nilfs);
 227
 228                 /* update GC protection for recent segments */
 229                 if (nilfs->ns_sbh[1]) {
 230                         if (flag == NILFS_SB_COMMIT_ALL) {
 231                                 set_buffer_dirty(nilfs->ns_sbh[1]);
 232                                 if (sync_dirty_buffer(nilfs->ns_sbh[1]) < 0)
 233                                         goto out;
 234                         }
 235                         if (le64_to_cpu(nilfs->ns_sbp[1]->s_last_cno) <
 236                             le64_to_cpu(nilfs->ns_sbp[0]->s_last_cno))
 237                                 sbp = nilfs->ns_sbp[1];
 238                 }
 239
 240                 spin_lock(&nilfs->ns_last_segment_lock);
 241                 nilfs->ns_prot_seq = le64_to_cpu(sbp->s_last_seq);
 242                 spin_unlock(&nilfs->ns_last_segment_lock);
 243         }
 244  out:
 245         return err;
 246 }
 247
 248 void nilfs_set_log_cursor(struct nilfs_super_block *sbp,
 249                           struct the_nilfs *nilfs)
 250 {
 251         sector_t nfreeblocks;
 252
 253         /* nilfs->ns_sem must be locked by the caller. */
 254         nilfs_count_free_blocks(nilfs, &nfreeblocks);
 255         sbp->s_free_blocks_count = cpu_to_le64(nfreeblocks);
 256
 257         spin_lock(&nilfs->ns_last_segment_lock);
 258         sbp->s_last_seq = cpu_to_le64(nilfs->ns_last_seq);
 259         sbp->s_last_pseg = cpu_to_le64(nilfs->ns_last_pseg);
 260         sbp->s_last_cno = cpu_to_le64(nilfs->ns_last_cno);
 261         spin_unlock(&nilfs->ns_last_segment_lock);
 262 }
 263
 264 struct nilfs_super_block **nilfs_prepare_super(struct super_block *sb,
 265                                                int flip)
 266 {
 267         struct the_nilfs *nilfs = sb->s_fs_info;
 268         struct nilfs_super_block **sbp = nilfs->ns_sbp;
 269
 270         /* nilfs->ns_sem must be locked by the caller. */
 271         if (sbp[0]->s_magic != cpu_to_le16(NILFS_SUPER_MAGIC)) {
 272                 if (sbp[1] &&
 273                     sbp[1]->s_magic == cpu_to_le16(NILFS_SUPER_MAGIC)) {
 274                         memcpy(sbp[0], sbp[1], nilfs->ns_sbsize);
 275                 } else {
 276                         printk(KERN_CRIT "NILFS: superblock broke on dev %s\n",
 277                                sb->s_id);
 278                         return NULL;
 279                 }
 280         } else if (sbp[1] &&
 281                    sbp[1]->s_magic != cpu_to_le16(NILFS_SUPER_MAGIC)) {
 282                         memcpy(sbp[1], sbp[0], nilfs->ns_sbsize);
 283         }
 284
 285         if (flip && sbp[1])
 286                 nilfs_swap_super_block(nilfs);
 287
 288         return sbp;
 289 }
 290
 291 int nilfs_commit_super(struct super_block *sb, int flag)
 292 {
 293         struct the_nilfs *nilfs = sb->s_fs_info;
 294         struct nilfs_super_block **sbp = nilfs->ns_sbp;
 295         time_t t;
 296
 297         /* nilfs->ns_sem must be locked by the caller. */
 298         t = get_seconds();
 299         nilfs->ns_sbwtime = t;
 300         sbp[0]->s_wtime = cpu_to_le64(t);
 301         sbp[0]->s_sum = 0;
 302         sbp[0]->s_sum = cpu_to_le32(crc32_le(nilfs->ns_crc_seed,
 303                                              (unsigned char *)sbp[0],
 304                                              nilfs->ns_sbsize));
 305         if (flag == NILFS_SB_COMMIT_ALL && sbp[1]) {
 306                 sbp[1]->s_wtime = sbp[0]->s_wtime;
 307                 sbp[1]->s_sum = 0;
 308                 sbp[1]->s_sum = cpu_to_le32(crc32_le(nilfs->ns_crc_seed,
 309                                             (unsigned char *)sbp[1],
 310                                             nilfs->ns_sbsize));
 311         }
 312         clear_nilfs_sb_dirty(nilfs);
 313         return nilfs_sync_super(sb, flag);
 314 }
 315
 316 /**
 317  * nilfs_cleanup_super() - write filesystem state for cleanup
 318  * @sb: super block instance to be unmounted or degraded to read-only
 319  *
 320  * This function restores state flags in the on-disk super block.
 321  * This will set "clean" flag (i.e. NILFS_VALID_FS) unless the
 322  * filesystem was not clean previously.
 323  */
 324 int nilfs_cleanup_super(struct super_block *sb)
 325 {
 326         struct the_nilfs *nilfs = sb->s_fs_info;
 327         struct nilfs_super_block **sbp;
 328         int flag = NILFS_SB_COMMIT;
 329         int ret = -EIO;
 330
 331         sbp = nilfs_prepare_super(sb, 0);
 332         if (sbp) {
 333                 sbp[0]->s_state = cpu_to_le16(nilfs->ns_mount_state);
 334                 nilfs_set_log_cursor(sbp[0], nilfs);
 335                 if (sbp[1] && sbp[0]->s_last_cno == sbp[1]->s_last_cno) {
 336                         /*
 337                          * make the "clean" flag also to the opposite
 338                          * super block if both super blocks point to
 339                          * the same checkpoint.
 340                          */
 341                         sbp[1]->s_state = sbp[0]->s_state;
 342                         flag = NILFS_SB_COMMIT_ALL;
 343                 }
 344                 ret = nilfs_commit_super(sb, flag);
 345         }
 346         return ret;
 347 }
 348
 349 /**
 350  * nilfs_move_2nd_super - relocate secondary super block
 351  * @sb: super block instance
 352  * @sb2off: new offset of the secondary super block (in bytes)
 353  */
 354 static int nilfs_move_2nd_super(struct super_block *sb, loff_t sb2off)
 355 {
 356         struct the_nilfs *nilfs = sb->s_fs_info;
 357         struct buffer_head *nsbh;
 358         struct nilfs_super_block *nsbp;
 359         sector_t blocknr, newblocknr;
 360         unsigned long offset;
 361         int sb2i = -1;  /* array index of the secondary superblock */
 362         int ret = 0;
 363
 364         /* nilfs->ns_sem must be locked by the caller. */
 365         if (nilfs->ns_sbh[1] &&
 366             nilfs->ns_sbh[1]->b_blocknr > nilfs->ns_first_data_block) {
 367                 sb2i = 1;
 368                 blocknr = nilfs->ns_sbh[1]->b_blocknr;
 369         } else if (nilfs->ns_sbh[0]->b_blocknr > nilfs->ns_first_data_block) {
 370                 sb2i = 0;
 371                 blocknr = nilfs->ns_sbh[0]->b_blocknr;
 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         return err;
 518 }
 519
 520 int nilfs_attach_checkpoint(struct super_block *sb, __u64 cno, int curr_mnt,
 521                             struct nilfs_root **rootp)
 522 {
 523         struct the_nilfs *nilfs = sb->s_fs_info;
 524         struct nilfs_root *root;
 525         struct nilfs_checkpoint *raw_cp;
 526         struct buffer_head *bh_cp;
 527         int err = -ENOMEM;
 528
 529         root = nilfs_find_or_create_root(
 530                 nilfs, curr_mnt ? NILFS_CPTREE_CURRENT_CNO : cno);
 531         if (!root)
 532                 return err;
 533
 534         if (root->ifile)
 535                 goto reuse; /* already attached checkpoint */
 536
 537         down_read(&nilfs->ns_segctor_sem);
 538         err = nilfs_cpfile_get_checkpoint(nilfs->ns_cpfile, cno, 0, &raw_cp,
 539                                           &bh_cp);
 540         up_read(&nilfs->ns_segctor_sem);
 541         if (unlikely(err)) {
 542                 if (err == -ENOENT || err == -EINVAL) {
 543                         printk(KERN_ERR
 544                                "NILFS: Invalid checkpoint "
 545                                "(checkpoint number=%llu)\n",
 546                                (unsigned long long)cno);
 547                         err = -EINVAL;
 548                 }
 549                 goto failed;
 550         }
 551
 552         err = nilfs_ifile_read(sb, root, nilfs->ns_inode_size,
 553                                &raw_cp->cp_ifile_inode, &root->ifile);
 554         if (err)
 555                 goto failed_bh;
 556
 557         atomic64_set(&root->inodes_count,
 558                         le64_to_cpu(raw_cp->cp_inodes_count));
 559         atomic64_set(&root->blocks_count,
 560                         le64_to_cpu(raw_cp->cp_blocks_count));
 561
 562         nilfs_cpfile_put_checkpoint(nilfs->ns_cpfile, cno, bh_cp);
 563
 564  reuse:
 565         *rootp = root;
 566         return 0;
 567
 568  failed_bh:
 569         nilfs_cpfile_put_checkpoint(nilfs->ns_cpfile, cno, bh_cp);
 570  failed:
 571         nilfs_put_root(root);
 572
 573         return err;
 574 }
 575
 576 static int nilfs_freeze(struct super_block *sb)
 577 {
 578         struct the_nilfs *nilfs = sb->s_fs_info;
 579         int err;
 580
 581         if (sb->s_flags & MS_RDONLY)
 582                 return 0;
 583
 584         /* Mark super block clean */
 585         down_write(&nilfs->ns_sem);
 586         err = nilfs_cleanup_super(sb);
 587         up_write(&nilfs->ns_sem);
 588         return err;
 589 }
 590
 591 static int nilfs_unfreeze(struct super_block *sb)
 592 {
 593         struct the_nilfs *nilfs = sb->s_fs_info;
 594
 595         if (sb->s_flags & MS_RDONLY)
 596                 return 0;
 597
 598         down_write(&nilfs->ns_sem);
 599         nilfs_setup_super(sb, false);
 600         up_write(&nilfs->ns_sem);
 601         return 0;
 602 }
 603
 604 static int nilfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 605 {
 606         struct super_block *sb = dentry->d_sb;
 607         struct nilfs_root *root = NILFS_I(dentry->d_inode)->i_root;
 608         struct the_nilfs *nilfs = root->nilfs;
 609         u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
 610         unsigned long long blocks;
 611         unsigned long overhead;
 612         unsigned long nrsvblocks;
 613         sector_t nfreeblocks;
 614         u64 nmaxinodes, nfreeinodes;
 615         int err;
 616
 617         /*
 618          * Compute all of the segment blocks
 619          *
 620          * The blocks before first segment and after last segment
 621          * are excluded.
 622          */
 623         blocks = nilfs->ns_blocks_per_segment * nilfs->ns_nsegments
 624                 - nilfs->ns_first_data_block;
 625         nrsvblocks = nilfs->ns_nrsvsegs * nilfs->ns_blocks_per_segment;
 626
 627         /*
 628          * Compute the overhead
 629          *
 630          * When distributing meta data blocks outside segment structure,
 631          * We must count them as the overhead.
 632          */
 633         overhead = 0;
 634
 635         err = nilfs_count_free_blocks(nilfs, &nfreeblocks);
 636         if (unlikely(err))
 637                 return err;
 638
 639         err = nilfs_ifile_count_free_inodes(root->ifile,
 640                                             &nmaxinodes, &nfreeinodes);
 641         if (unlikely(err)) {
 642                 printk(KERN_WARNING
 643                         "NILFS warning: fail to count free inodes: err %d.\n",
 644                         err);
 645                 if (err == -ERANGE) {
 646                         /*
 647                          * If nilfs_palloc_count_max_entries() returns
 648                          * -ERANGE error code then we simply treat
 649                          * curent inodes count as maximum possible and
 650                          * zero as free inodes value.
 651                          */
 652                         nmaxinodes = atomic64_read(&root->inodes_count);
 653                         nfreeinodes = 0;
 654                         err = 0;
 655                 } else
 656                         return err;
 657         }
 658
 659         buf->f_type = NILFS_SUPER_MAGIC;
 660         buf->f_bsize = sb->s_blocksize;
 661         buf->f_blocks = blocks - overhead;
 662         buf->f_bfree = nfreeblocks;
 663         buf->f_bavail = (buf->f_bfree >= nrsvblocks) ?
 664                 (buf->f_bfree - nrsvblocks) : 0;
 665         buf->f_files = nmaxinodes;
 666         buf->f_ffree = nfreeinodes;
 667         buf->f_namelen = NILFS_NAME_LEN;
 668         buf->f_fsid.val[0] = (u32)id;
 669         buf->f_fsid.val[1] = (u32)(id >> 32);
 670
 671         return 0;
 672 }
 673
 674 static int nilfs_show_options(struct seq_file *seq, struct dentry *dentry)
 675 {
 676         struct super_block *sb = dentry->d_sb;
 677         struct the_nilfs *nilfs = sb->s_fs_info;
 678         struct nilfs_root *root = NILFS_I(dentry->d_inode)->i_root;
 679
 680         if (!nilfs_test_opt(nilfs, BARRIER))
 681                 seq_puts(seq, ",nobarrier");
 682         if (root->cno != NILFS_CPTREE_CURRENT_CNO)
 683                 seq_printf(seq, ",cp=%llu", (unsigned long long)root->cno);
 684         if (nilfs_test_opt(nilfs, ERRORS_PANIC))
 685                 seq_puts(seq, ",errors=panic");
 686         if (nilfs_test_opt(nilfs, ERRORS_CONT))
 687                 seq_puts(seq, ",errors=continue");
 688         if (nilfs_test_opt(nilfs, STRICT_ORDER))
 689                 seq_puts(seq, ",order=strict");
 690         if (nilfs_test_opt(nilfs, NORECOVERY))
 691                 seq_puts(seq, ",norecovery");
 692         if (nilfs_test_opt(nilfs, DISCARD))
 693                 seq_puts(seq, ",discard");
 694
 695         return 0;
 696 }
 697
 698 static const struct super_operations nilfs_sops = {
 699         .alloc_inode    = nilfs_alloc_inode,
 700         .destroy_inode  = nilfs_destroy_inode,
 701         .dirty_inode    = nilfs_dirty_inode,
 702         .evict_inode    = nilfs_evict_inode,
 703         .put_super      = nilfs_put_super,
 704         .sync_fs        = nilfs_sync_fs,
 705         .freeze_fs      = nilfs_freeze,
 706         .unfreeze_fs    = nilfs_unfreeze,
 707         .statfs         = nilfs_statfs,
 708         .remount_fs     = nilfs_remount,
 709         .show_options = nilfs_show_options
 710 };
 711
 712 enum {
 713         Opt_err_cont, Opt_err_panic, Opt_err_ro,
 714         Opt_barrier, Opt_nobarrier, Opt_snapshot, Opt_order, Opt_norecovery,
 715         Opt_discard, Opt_nodiscard, Opt_err,
 716 };
 717
 718 static match_table_t tokens = {
 719         {Opt_err_cont, "errors=continue"},
 720         {Opt_err_panic, "errors=panic"},
 721         {Opt_err_ro, "errors=remount-ro"},
 722         {Opt_barrier, "barrier"},
 723         {Opt_nobarrier, "nobarrier"},
 724         {Opt_snapshot, "cp=%u"},
 725         {Opt_order, "order=%s"},
 726         {Opt_norecovery, "norecovery"},
 727         {Opt_discard, "discard"},
 728         {Opt_nodiscard, "nodiscard"},
 729         {Opt_err, NULL}
 730 };
 731
 732 static int parse_options(char *options, struct super_block *sb, int is_remount)
 733 {
 734         struct the_nilfs *nilfs = sb->s_fs_info;
 735         char *p;
 736         substring_t args[MAX_OPT_ARGS];
 737
 738         if (!options)
 739                 return 1;
 740
 741         while ((p = strsep(&options, ",")) != NULL) {
 742                 int token;
 743                 if (!*p)
 744                         continue;
 745
 746                 token = match_token(p, tokens, args);
 747                 switch (token) {
 748                 case Opt_barrier:
 749                         nilfs_set_opt(nilfs, BARRIER);
 750                         break;
 751                 case Opt_nobarrier:
 752                         nilfs_clear_opt(nilfs, BARRIER);
 753                         break;
 754                 case Opt_order:
 755                         if (strcmp(args[0].from, "relaxed") == 0)
 756                                 /* Ordered data semantics */
 757                                 nilfs_clear_opt(nilfs, STRICT_ORDER);
 758                         else if (strcmp(args[0].from, "strict") == 0)
 759                                 /* Strict in-order semantics */
 760                                 nilfs_set_opt(nilfs, STRICT_ORDER);
 761                         else
 762                                 return 0;
 763                         break;
 764                 case Opt_err_panic:
 765                         nilfs_write_opt(nilfs, ERROR_MODE, ERRORS_PANIC);
 766                         break;
 767                 case Opt_err_ro:
 768                         nilfs_write_opt(nilfs, ERROR_MODE, ERRORS_RO);
 769                         break;
 770                 case Opt_err_cont:
 771                         nilfs_write_opt(nilfs, ERROR_MODE, ERRORS_CONT);
 772                         break;
 773                 case Opt_snapshot:
 774                         if (is_remount) {
 775                                 printk(KERN_ERR
 776                                        "NILFS: \"%s\" option is invalid "
 777                                        "for remount.\n", p);
 778                                 return 0;
 779                         }
 780                         break;
 781                 case Opt_norecovery:
 782                         nilfs_set_opt(nilfs, NORECOVERY);
 783                         break;
 784                 case Opt_discard:
 785                         nilfs_set_opt(nilfs, DISCARD);
 786                         break;
 787                 case Opt_nodiscard:
 788                         nilfs_clear_opt(nilfs, DISCARD);
 789                         break;
 790                 default:
 791                         printk(KERN_ERR
 792                                "NILFS: Unrecognized mount option \"%s\"\n", p);
 793                         return 0;
 794                 }
 795         }
 796         return 1;
 797 }
 798
 799 static inline void
 800 nilfs_set_default_options(struct super_block *sb,
 801                           struct nilfs_super_block *sbp)
 802 {
 803         struct the_nilfs *nilfs = sb->s_fs_info;
 804
 805         nilfs->ns_mount_opt =
 806                 NILFS_MOUNT_ERRORS_RO | NILFS_MOUNT_BARRIER;
 807 }
 808
 809 static int nilfs_setup_super(struct super_block *sb, int is_mount)
 810 {
 811         struct the_nilfs *nilfs = sb->s_fs_info;
 812         struct nilfs_super_block **sbp;
 813         int max_mnt_count;
 814         int mnt_count;
 815
 816         /* nilfs->ns_sem must be locked by the caller. */
 817         sbp = nilfs_prepare_super(sb, 0);
 818         if (!sbp)
 819                 return -EIO;
 820
 821         if (!is_mount)
 822                 goto skip_mount_setup;
 823
 824         max_mnt_count = le16_to_cpu(sbp[0]->s_max_mnt_count);
 825         mnt_count = le16_to_cpu(sbp[0]->s_mnt_count);
 826
 827         if (nilfs->ns_mount_state & NILFS_ERROR_FS) {
 828                 printk(KERN_WARNING
 829                        "NILFS warning: mounting fs with errors\n");
 830 #if 0
 831         } else if (max_mnt_count >= 0 && mnt_count >= max_mnt_count) {
 832                 printk(KERN_WARNING
 833                        "NILFS warning: maximal mount count reached\n");
 834 #endif
 835         }
 836         if (!max_mnt_count)
 837                 sbp[0]->s_max_mnt_count = cpu_to_le16(NILFS_DFL_MAX_MNT_COUNT);
 838
 839         sbp[0]->s_mnt_count = cpu_to_le16(mnt_count + 1);
 840         sbp[0]->s_mtime = cpu_to_le64(get_seconds());
 841
 842 skip_mount_setup:
 843         sbp[0]->s_state =
 844                 cpu_to_le16(le16_to_cpu(sbp[0]->s_state) & ~NILFS_VALID_FS);
 845         /* synchronize sbp[1] with sbp[0] */
 846         if (sbp[1])
 847                 memcpy(sbp[1], sbp[0], nilfs->ns_sbsize);
 848         return nilfs_commit_super(sb, NILFS_SB_COMMIT_ALL);
 849 }
 850
 851 struct nilfs_super_block *nilfs_read_super_block(struct super_block *sb,
 852                                                  u64 pos, int blocksize,
 853                                                  struct buffer_head **pbh)
 854 {
 855         unsigned long long sb_index = pos;
 856         unsigned long offset;
 857
 858         offset = do_div(sb_index, blocksize);
 859         *pbh = sb_bread(sb, sb_index);
 860         if (!*pbh)
 861                 return NULL;
 862         return (struct nilfs_super_block *)((char *)(*pbh)->b_data + offset);
 863 }
 864
 865 int nilfs_store_magic_and_option(struct super_block *sb,
 866                                  struct nilfs_super_block *sbp,
 867                                  char *data)
 868 {
 869         struct the_nilfs *nilfs = sb->s_fs_info;
 870
 871         sb->s_magic = le16_to_cpu(sbp->s_magic);
 872
 873         /* FS independent flags */
 874 #ifdef NILFS_ATIME_DISABLE
 875         sb->s_flags |= MS_NOATIME;
 876 #endif
 877
 878         nilfs_set_default_options(sb, sbp);
 879
 880         nilfs->ns_resuid = le16_to_cpu(sbp->s_def_resuid);
 881         nilfs->ns_resgid = le16_to_cpu(sbp->s_def_resgid);
 882         nilfs->ns_interval = le32_to_cpu(sbp->s_c_interval);
 883         nilfs->ns_watermark = le32_to_cpu(sbp->s_c_block_max);
 884
 885         return !parse_options(data, sb, 0) ? -EINVAL : 0 ;
 886 }
 887
 888 int nilfs_check_feature_compatibility(struct super_block *sb,
 889                                       struct nilfs_super_block *sbp)
 890 {
 891         __u64 features;
 892
 893         features = le64_to_cpu(sbp->s_feature_incompat) &
 894                 ~NILFS_FEATURE_INCOMPAT_SUPP;
 895         if (features) {
 896                 printk(KERN_ERR "NILFS: couldn't mount because of unsupported "
 897                        "optional features (%llx)\n",
 898                        (unsigned long long)features);
 899                 return -EINVAL;
 900         }
 901         features = le64_to_cpu(sbp->s_feature_compat_ro) &
 902                 ~NILFS_FEATURE_COMPAT_RO_SUPP;
 903         if (!(sb->s_flags & MS_RDONLY) && features) {
 904                 printk(KERN_ERR "NILFS: couldn't mount RDWR because of "
 905                        "unsupported optional features (%llx)\n",
 906                        (unsigned long long)features);
 907                 return -EINVAL;
 908         }
 909         return 0;
 910 }
 911
 912 static int nilfs_get_root_dentry(struct super_block *sb,
 913                                  struct nilfs_root *root,
 914                                  struct dentry **root_dentry)
 915 {
 916         struct inode *inode;
 917         struct dentry *dentry;
 918         int ret = 0;
 919
 920         inode = nilfs_iget(sb, root, NILFS_ROOT_INO);
 921         if (IS_ERR(inode)) {
 922                 printk(KERN_ERR "NILFS: get root inode failed\n");
 923                 ret = PTR_ERR(inode);
 924                 goto out;
 925         }
 926         if (!S_ISDIR(inode->i_mode) || !inode->i_blocks || !inode->i_size) {
 927                 iput(inode);
 928                 printk(KERN_ERR "NILFS: corrupt root inode.\n");
 929                 ret = -EINVAL;
 930                 goto out;
 931         }
 932
 933         if (root->cno == NILFS_CPTREE_CURRENT_CNO) {
 934                 dentry = d_find_alias(inode);
 935                 if (!dentry) {
 936                         dentry = d_make_root(inode);
 937                         if (!dentry) {
 938                                 ret = -ENOMEM;
 939                                 goto failed_dentry;
 940                         }
 941                 } else {
 942                         iput(inode);
 943                 }
 944         } else {
 945                 dentry = d_obtain_alias(inode);
 946                 if (IS_ERR(dentry)) {
 947                         ret = PTR_ERR(dentry);
 948                         goto failed_dentry;
 949                 }
 950         }
 951         *root_dentry = dentry;
 952  out:
 953         return ret;
 954
 955  failed_dentry:
 956         printk(KERN_ERR "NILFS: get root dentry failed\n");
 957         goto out;
 958 }
 959
 960 static int nilfs_attach_snapshot(struct super_block *s, __u64 cno,
 961                                  struct dentry **root_dentry)
 962 {
 963         struct the_nilfs *nilfs = s->s_fs_info;
 964         struct nilfs_root *root;
 965         int ret;
 966
 967         mutex_lock(&nilfs->ns_snapshot_mount_mutex);
 968
 969         down_read(&nilfs->ns_segctor_sem);
 970         ret = nilfs_cpfile_is_snapshot(nilfs->ns_cpfile, cno);
 971         up_read(&nilfs->ns_segctor_sem);
 972         if (ret < 0) {
 973                 ret = (ret == -ENOENT) ? -EINVAL : ret;
 974                 goto out;
 975         } else if (!ret) {
 976                 printk(KERN_ERR "NILFS: The specified checkpoint is "
 977                        "not a snapshot (checkpoint number=%llu).\n",
 978                        (unsigned long long)cno);
 979                 ret = -EINVAL;
 980                 goto out;
 981         }
 982
 983         ret = nilfs_attach_checkpoint(s, cno, false, &root);
 984         if (ret) {
 985                 printk(KERN_ERR "NILFS: error loading snapshot "
 986                        "(checkpoint number=%llu).\n",
 987                (unsigned long long)cno);
 988                 goto out;
 989         }
 990         ret = nilfs_get_root_dentry(s, root, root_dentry);
 991         nilfs_put_root(root);
 992  out:
 993         mutex_unlock(&nilfs->ns_snapshot_mount_mutex);
 994         return ret;
 995 }
 996
 997 /**
 998  * nilfs_tree_is_busy() - try to shrink dentries of a checkpoint
 999  * @root_dentry: root dentry of the tree to be shrunk
1000  *
1001  * This function returns true if the tree was in-use.
1002  */
1003 static bool nilfs_tree_is_busy(struct dentry *root_dentry)
1004 {
1005         shrink_dcache_parent(root_dentry);
1006         return d_count(root_dentry) > 1;
1007 }
1008
1009 int nilfs_checkpoint_is_mounted(struct super_block *sb, __u64 cno)
1010 {
1011         struct the_nilfs *nilfs = sb->s_fs_info;
1012         struct nilfs_root *root;
1013         struct inode *inode;
1014         struct dentry *dentry;
1015         int ret;
1016
1017         if (cno < 0 || cno > nilfs->ns_cno)
1018                 return false;
1019
1020         if (cno >= nilfs_last_cno(nilfs))
1021                 return true;    /* protect recent checkpoints */
1022
1023         ret = false;
1024         root = nilfs_lookup_root(nilfs, cno);
1025         if (root) {
1026                 inode = nilfs_ilookup(sb, root, NILFS_ROOT_INO);
1027                 if (inode) {
1028                         dentry = d_find_alias(inode);
1029                         if (dentry) {
1030                                 ret = nilfs_tree_is_busy(dentry);
1031                                 dput(dentry);
1032                         }
1033                         iput(inode);
1034                 }
1035                 nilfs_put_root(root);
1036         }
1037         return ret;
1038 }
1039
1040 /**
1041  * nilfs_fill_super() - initialize a super block instance
1042  * @sb: super_block
1043  * @data: mount options
1044  * @silent: silent mode flag
1045  *
1046  * This function is called exclusively by nilfs->ns_mount_mutex.
1047  * So, the recovery process is protected from other simultaneous mounts.
1048  */
1049 static int
1050 nilfs_fill_super(struct super_block *sb, void *data, int silent)
1051 {
1052         struct the_nilfs *nilfs;
1053         struct nilfs_root *fsroot;
1054         struct backing_dev_info *bdi;
1055         __u64 cno;
1056         int err;
1057
1058         nilfs = alloc_nilfs(sb->s_bdev);
1059         if (!nilfs)
1060                 return -ENOMEM;
1061
1062         sb->s_fs_info = nilfs;
1063
1064         err = init_nilfs(nilfs, sb, (char *)data);
1065         if (err)
1066                 goto failed_nilfs;
1067
1068         sb->s_op = &nilfs_sops;
1069         sb->s_export_op = &nilfs_export_ops;
1070         sb->s_root = NULL;
1071         sb->s_time_gran = 1;
1072         sb->s_max_links = NILFS_LINK_MAX;
1073
1074         bdi = sb->s_bdev->bd_inode->i_mapping->backing_dev_info;
1075         sb->s_bdi = bdi ? : &default_backing_dev_info;
1076
1077         err = load_nilfs(nilfs, sb);
1078         if (err)
1079                 goto failed_nilfs;
1080
1081         cno = nilfs_last_cno(nilfs);
1082         err = nilfs_attach_checkpoint(sb, cno, true, &fsroot);
1083         if (err) {
1084                 printk(KERN_ERR "NILFS: error loading last checkpoint "
1085                        "(checkpoint number=%llu).\n", (unsigned long long)cno);
1086                 goto failed_unload;
1087         }
1088
1089         if (!(sb->s_flags & MS_RDONLY)) {
1090                 err = nilfs_attach_log_writer(sb, fsroot);
1091                 if (err)
1092                         goto failed_checkpoint;
1093         }
1094
1095         err = nilfs_get_root_dentry(sb, fsroot, &sb->s_root);
1096         if (err)
1097                 goto failed_segctor;
1098
1099         nilfs_put_root(fsroot);
1100
1101         if (!(sb->s_flags & MS_RDONLY)) {
1102                 down_write(&nilfs->ns_sem);
1103                 nilfs_setup_super(sb, true);
1104                 up_write(&nilfs->ns_sem);
1105         }
1106
1107         return 0;
1108
1109  failed_segctor:
1110         nilfs_detach_log_writer(sb);
1111
1112  failed_checkpoint:
1113         nilfs_put_root(fsroot);
1114
1115  failed_unload:
1116         iput(nilfs->ns_sufile);
1117         iput(nilfs->ns_cpfile);
1118         iput(nilfs->ns_dat);
1119
1120  failed_nilfs:
1121         destroy_nilfs(nilfs);
1122         return err;
1123 }
1124
1125 static int nilfs_remount(struct super_block *sb, int *flags, char *data)
1126 {
1127         struct the_nilfs *nilfs = sb->s_fs_info;
1128         unsigned long old_sb_flags;
1129         unsigned long old_mount_opt;
1130         int err;
1131
1132         sync_filesystem(sb);
1133         old_sb_flags = sb->s_flags;
1134         old_mount_opt = nilfs->ns_mount_opt;
1135
1136         if (!parse_options(data, sb, 1)) {
1137                 err = -EINVAL;
1138                 goto restore_opts;
1139         }
1140         sb->s_flags = (sb->s_flags & ~MS_POSIXACL);
1141
1142         err = -EINVAL;
1143
1144         if (!nilfs_valid_fs(nilfs)) {
1145                 printk(KERN_WARNING "NILFS (device %s): couldn't "
1146                        "remount because the filesystem is in an "
1147                        "incomplete recovery state.\n", sb->s_id);
1148                 goto restore_opts;
1149         }
1150
1151         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
1152                 goto out;
1153         if (*flags & MS_RDONLY) {
1154                 /* Shutting down log writer */
1155                 nilfs_detach_log_writer(sb);
1156                 sb->s_flags |= MS_RDONLY;
1157
1158                 /*
1159                  * Remounting a valid RW partition RDONLY, so set
1160                  * the RDONLY flag and then mark the partition as valid again.
1161                  */
1162                 down_write(&nilfs->ns_sem);
1163                 nilfs_cleanup_super(sb);
1164                 up_write(&nilfs->ns_sem);
1165         } else {
1166                 __u64 features;
1167                 struct nilfs_root *root;
1168
1169                 /*
1170                  * Mounting a RDONLY partition read-write, so reread and
1171                  * store the current valid flag.  (It may have been changed
1172                  * by fsck since we originally mounted the partition.)
1173                  */
1174                 down_read(&nilfs->ns_sem);
1175                 features = le64_to_cpu(nilfs->ns_sbp[0]->s_feature_compat_ro) &
1176                         ~NILFS_FEATURE_COMPAT_RO_SUPP;
1177                 up_read(&nilfs->ns_sem);
1178                 if (features) {
1179                         printk(KERN_WARNING "NILFS (device %s): couldn't "
1180                                "remount RDWR because of unsupported optional "
1181                                "features (%llx)\n",
1182                                sb->s_id, (unsigned long long)features);
1183                         err = -EROFS;
1184                         goto restore_opts;
1185                 }
1186
1187                 sb->s_flags &= ~MS_RDONLY;
1188
1189                 root = NILFS_I(sb->s_root->d_inode)->i_root;
1190                 err = nilfs_attach_log_writer(sb, root);
1191                 if (err)
1192                         goto restore_opts;
1193
1194                 down_write(&nilfs->ns_sem);
1195                 nilfs_setup_super(sb, true);
1196                 up_write(&nilfs->ns_sem);
1197         }
1198  out:
1199         return 0;
1200
1201  restore_opts:
1202         sb->s_flags = old_sb_flags;
1203         nilfs->ns_mount_opt = old_mount_opt;
1204         return err;
1205 }
1206
1207 struct nilfs_super_data {
1208         struct block_device *bdev;
1209         __u64 cno;
1210         int flags;
1211 };
1212
1213 /**
1214  * nilfs_identify - pre-read mount options needed to identify mount instance
1215  * @data: mount options
1216  * @sd: nilfs_super_data
1217  */
1218 static int nilfs_identify(char *data, struct nilfs_super_data *sd)
1219 {
1220         char *p, *options = data;
1221         substring_t args[MAX_OPT_ARGS];
1222         int token;
1223         int ret = 0;
1224
1225         do {
1226                 p = strsep(&options, ",");
1227                 if (p != NULL && *p) {
1228                         token = match_token(p, tokens, args);
1229                         if (token == Opt_snapshot) {
1230                                 if (!(sd->flags & MS_RDONLY)) {
1231                                         ret++;
1232                                 } else {
1233                                         sd->cno = simple_strtoull(args[0].from,
1234                                                                   NULL, 0);
1235                                         /*
1236                                          * No need to see the end pointer;
1237                                          * match_token() has done syntax
1238                                          * checking.
1239                                          */
1240                                         if (sd->cno == 0)
1241                                                 ret++;
1242                                 }
1243                         }
1244                         if (ret)
1245                                 printk(KERN_ERR
1246                                        "NILFS: invalid mount option: %s\n", p);
1247                 }
1248                 if (!options)
1249                         break;
1250                 BUG_ON(options == data);
1251                 *(options - 1) = ',';
1252         } while (!ret);
1253         return ret;
1254 }
1255
1256 static int nilfs_set_bdev_super(struct super_block *s, void *data)
1257 {
1258         s->s_bdev = data;
1259         s->s_dev = s->s_bdev->bd_dev;
1260         return 0;
1261 }
1262
1263 static int nilfs_test_bdev_super(struct super_block *s, void *data)
1264 {
1265         return (void *)s->s_bdev == data;
1266 }
1267
1268 static struct dentry *
1269 nilfs_mount(struct file_system_type *fs_type, int flags,
1270              const char *dev_name, void *data)
1271 {
1272         struct nilfs_super_data sd;
1273         struct super_block *s;
1274         fmode_t mode = FMODE_READ | FMODE_EXCL;
1275         struct dentry *root_dentry;
1276         int err, s_new = false;
1277
1278         if (!(flags & MS_RDONLY))
1279                 mode |= FMODE_WRITE;
1280
1281         sd.bdev = blkdev_get_by_path(dev_name, mode, fs_type);
1282         if (IS_ERR(sd.bdev))
1283                 return ERR_CAST(sd.bdev);
1284
1285         sd.cno = 0;
1286         sd.flags = flags;
1287         if (nilfs_identify((char *)data, &sd)) {
1288                 err = -EINVAL;
1289                 goto failed;
1290         }
1291
1292         /*
1293          * once the super is inserted into the list by sget, s_umount
1294          * will protect the lockfs code from trying to start a snapshot
1295          * while we are mounting
1296          */
1297         mutex_lock(&sd.bdev->bd_fsfreeze_mutex);
1298         if (sd.bdev->bd_fsfreeze_count > 0) {
1299                 mutex_unlock(&sd.bdev->bd_fsfreeze_mutex);
1300                 err = -EBUSY;
1301                 goto failed;
1302         }
1303         s = sget(fs_type, nilfs_test_bdev_super, nilfs_set_bdev_super, flags,
1304                  sd.bdev);
1305         mutex_unlock(&sd.bdev->bd_fsfreeze_mutex);
1306         if (IS_ERR(s)) {
1307                 err = PTR_ERR(s);
1308                 goto failed;
1309         }
1310
1311         if (!s->s_root) {
1312                 char b[BDEVNAME_SIZE];
1313
1314                 s_new = true;
1315
1316                 /* New superblock instance created */
1317                 s->s_mode = mode;
1318                 strlcpy(s->s_id, bdevname(sd.bdev, b), sizeof(s->s_id));
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         if (nilfs_inode_cachep)
1405                 kmem_cache_destroy(nilfs_inode_cachep);
1406         if (nilfs_transaction_cachep)
1407                 kmem_cache_destroy(nilfs_transaction_cachep);
1408         if (nilfs_segbuf_cachep)
1409                 kmem_cache_destroy(nilfs_segbuf_cachep);
1410         if (nilfs_btree_path_cache)
1411                 kmem_cache_destroy(nilfs_btree_path_cache);
1412 }
1413
1414 static int __init nilfs_init_cachep(void)
1415 {
1416         nilfs_inode_cachep = kmem_cache_create("nilfs2_inode_cache",
1417                         sizeof(struct nilfs_inode_info), 0,
1418                         SLAB_RECLAIM_ACCOUNT, nilfs_inode_init_once);
1419         if (!nilfs_inode_cachep)
1420                 goto fail;
1421
1422         nilfs_transaction_cachep = kmem_cache_create("nilfs2_transaction_cache",
1423                         sizeof(struct nilfs_transaction_info), 0,
1424                         SLAB_RECLAIM_ACCOUNT, NULL);
1425         if (!nilfs_transaction_cachep)
1426                 goto fail;
1427
1428         nilfs_segbuf_cachep = kmem_cache_create("nilfs2_segbuf_cache",
1429                         sizeof(struct nilfs_segment_buffer), 0,
1430                         SLAB_RECLAIM_ACCOUNT, nilfs_segbuf_init_once);
1431         if (!nilfs_segbuf_cachep)
1432                 goto fail;
1433
1434         nilfs_btree_path_cache = kmem_cache_create("nilfs2_btree_path_cache",
1435                         sizeof(struct nilfs_btree_path) * NILFS_BTREE_LEVEL_MAX,
1436                         0, 0, NULL);
1437         if (!nilfs_btree_path_cache)
1438                 goto fail;
1439
1440         return 0;
1441
1442 fail:
1443         nilfs_destroy_cachep();
1444         return -ENOMEM;
1445 }
1446
1447 static int __init init_nilfs_fs(void)
1448 {
1449         int err;
1450
1451         err = nilfs_init_cachep();
1452         if (err)
1453                 goto fail;
1454
1455         err = register_filesystem(&nilfs_fs_type);
1456         if (err)
1457                 goto free_cachep;
1458
1459         printk(KERN_INFO "NILFS version 2 loaded\n");
1460         return 0;
1461
1462 free_cachep:
1463         nilfs_destroy_cachep();
1464 fail:
1465         return err;
1466 }
1467
1468 static void __exit exit_nilfs_fs(void)
1469 {
1470         nilfs_destroy_cachep();
1471         unregister_filesystem(&nilfs_fs_type);
1472 }
1473
1474 module_init(init_nilfs_fs)
1475 module_exit(exit_nilfs_fs)