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);
 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         nilfs->ns_flushed_device = 1;
 314         /* make sure store to ns_flushed_device cannot be reordered */
 315         smp_wmb();
 316         return nilfs_sync_super(sb, flag);
 317 }
 318
 319 /**
 320  * nilfs_cleanup_super() - write filesystem state for cleanup
 321  * @sb: super block instance to be unmounted or degraded to read-only
 322  *
 323  * This function restores state flags in the on-disk super block.
 324  * This will set "clean" flag (i.e. NILFS_VALID_FS) unless the
 325  * filesystem was not clean previously.
 326  */
 327 int nilfs_cleanup_super(struct super_block *sb)
 328 {
 329         struct the_nilfs *nilfs = sb->s_fs_info;
 330         struct nilfs_super_block **sbp;
 331         int flag = NILFS_SB_COMMIT;
 332         int ret = -EIO;
 333
 334         sbp = nilfs_prepare_super(sb, 0);
 335         if (sbp) {
 336                 sbp[0]->s_state = cpu_to_le16(nilfs->ns_mount_state);
 337                 nilfs_set_log_cursor(sbp[0], nilfs);
 338                 if (sbp[1] && sbp[0]->s_last_cno == sbp[1]->s_last_cno) {
 339                         /*
 340                          * make the "clean" flag also to the opposite
 341                          * super block if both super blocks point to
 342                          * the same checkpoint.
 343                          */
 344                         sbp[1]->s_state = sbp[0]->s_state;
 345                         flag = NILFS_SB_COMMIT_ALL;
 346                 }
 347                 ret = nilfs_commit_super(sb, flag);
 348         }
 349         return ret;
 350 }
 351
 352 /**
 353  * nilfs_move_2nd_super - relocate secondary super block
 354  * @sb: super block instance
 355  * @sb2off: new offset of the secondary super block (in bytes)
 356  */
 357 static int nilfs_move_2nd_super(struct super_block *sb, loff_t sb2off)
 358 {
 359         struct the_nilfs *nilfs = sb->s_fs_info;
 360         struct buffer_head *nsbh;
 361         struct nilfs_super_block *nsbp;
 362         sector_t blocknr, newblocknr;
 363         unsigned long offset;
 364         int sb2i;  /* array index of the secondary superblock */
 365         int ret = 0;
 366
 367         /* nilfs->ns_sem must be locked by the caller. */
 368         if (nilfs->ns_sbh[1] &&
 369             nilfs->ns_sbh[1]->b_blocknr > nilfs->ns_first_data_block) {
 370                 sb2i = 1;
 371                 blocknr = nilfs->ns_sbh[1]->b_blocknr;
 372         } else if (nilfs->ns_sbh[0]->b_blocknr > nilfs->ns_first_data_block) {
 373                 sb2i = 0;
 374                 blocknr = nilfs->ns_sbh[0]->b_blocknr;
 375         } else {
 376                 sb2i = -1;
 377                 blocknr = 0;
 378         }
 379         if (sb2i >= 0 && (u64)blocknr << nilfs->ns_blocksize_bits == sb2off)
 380                 goto out;  /* super block location is unchanged */
 381
 382         /* Get new super block buffer */
 383         newblocknr = sb2off >> nilfs->ns_blocksize_bits;
 384         offset = sb2off & (nilfs->ns_blocksize - 1);
 385         nsbh = sb_getblk(sb, newblocknr);
 386         if (!nsbh) {
 387                 printk(KERN_WARNING
 388                        "NILFS warning: unable to move secondary superblock "
 389                        "to block %llu\n", (unsigned long long)newblocknr);
 390                 ret = -EIO;
 391                 goto out;
 392         }
 393         nsbp = (void *)nsbh->b_data + offset;
 394         memset(nsbp, 0, nilfs->ns_blocksize);
 395
 396         if (sb2i >= 0) {
 397                 memcpy(nsbp, nilfs->ns_sbp[sb2i], nilfs->ns_sbsize);
 398                 brelse(nilfs->ns_sbh[sb2i]);
 399                 nilfs->ns_sbh[sb2i] = nsbh;
 400                 nilfs->ns_sbp[sb2i] = nsbp;
 401         } else if (nilfs->ns_sbh[0]->b_blocknr < nilfs->ns_first_data_block) {
 402                 /* secondary super block will be restored to index 1 */
 403                 nilfs->ns_sbh[1] = nsbh;
 404                 nilfs->ns_sbp[1] = nsbp;
 405         } else {
 406                 brelse(nsbh);
 407         }
 408 out:
 409         return ret;
 410 }
 411
 412 /**
 413  * nilfs_resize_fs - resize the filesystem
 414  * @sb: super block instance
 415  * @newsize: new size of the filesystem (in bytes)
 416  */
 417 int nilfs_resize_fs(struct super_block *sb, __u64 newsize)
 418 {
 419         struct the_nilfs *nilfs = sb->s_fs_info;
 420         struct nilfs_super_block **sbp;
 421         __u64 devsize, newnsegs;
 422         loff_t sb2off;
 423         int ret;
 424
 425         ret = -ERANGE;
 426         devsize = i_size_read(sb->s_bdev->bd_inode);
 427         if (newsize > devsize)
 428                 goto out;
 429
 430         /*
 431          * Write lock is required to protect some functions depending
 432          * on the number of segments, the number of reserved segments,
 433          * and so forth.
 434          */
 435         down_write(&nilfs->ns_segctor_sem);
 436
 437         sb2off = NILFS_SB2_OFFSET_BYTES(newsize);
 438         newnsegs = sb2off >> nilfs->ns_blocksize_bits;
 439         do_div(newnsegs, nilfs->ns_blocks_per_segment);
 440
 441         ret = nilfs_sufile_resize(nilfs->ns_sufile, newnsegs);
 442         up_write(&nilfs->ns_segctor_sem);
 443         if (ret < 0)
 444                 goto out;
 445
 446         ret = nilfs_construct_segment(sb);
 447         if (ret < 0)
 448                 goto out;
 449
 450         down_write(&nilfs->ns_sem);
 451         nilfs_move_2nd_super(sb, sb2off);
 452         ret = -EIO;
 453         sbp = nilfs_prepare_super(sb, 0);
 454         if (likely(sbp)) {
 455                 nilfs_set_log_cursor(sbp[0], nilfs);
 456                 /*
 457                  * Drop NILFS_RESIZE_FS flag for compatibility with
 458                  * mount-time resize which may be implemented in a
 459                  * future release.
 460                  */
 461                 sbp[0]->s_state = cpu_to_le16(le16_to_cpu(sbp[0]->s_state) &
 462                                               ~NILFS_RESIZE_FS);
 463                 sbp[0]->s_dev_size = cpu_to_le64(newsize);
 464                 sbp[0]->s_nsegments = cpu_to_le64(nilfs->ns_nsegments);
 465                 if (sbp[1])
 466                         memcpy(sbp[1], sbp[0], nilfs->ns_sbsize);
 467                 ret = nilfs_commit_super(sb, NILFS_SB_COMMIT_ALL);
 468         }
 469         up_write(&nilfs->ns_sem);
 470
 471         /*
 472          * Reset the range of allocatable segments last.  This order
 473          * is important in the case of expansion because the secondary
 474          * superblock must be protected from log write until migration
 475          * completes.
 476          */
 477         if (!ret)
 478                 nilfs_sufile_set_alloc_range(nilfs->ns_sufile, 0, newnsegs - 1);
 479 out:
 480         return ret;
 481 }
 482
 483 static void nilfs_put_super(struct super_block *sb)
 484 {
 485         struct the_nilfs *nilfs = sb->s_fs_info;
 486
 487         nilfs_detach_log_writer(sb);
 488
 489         if (!(sb->s_flags & MS_RDONLY)) {
 490                 down_write(&nilfs->ns_sem);
 491                 nilfs_cleanup_super(sb);
 492                 up_write(&nilfs->ns_sem);
 493         }
 494
 495         iput(nilfs->ns_sufile);
 496         iput(nilfs->ns_cpfile);
 497         iput(nilfs->ns_dat);
 498
 499         destroy_nilfs(nilfs);
 500         sb->s_fs_info = NULL;
 501 }
 502
 503 static int nilfs_sync_fs(struct super_block *sb, int wait)
 504 {
 505         struct the_nilfs *nilfs = sb->s_fs_info;
 506         struct nilfs_super_block **sbp;
 507         int err = 0;
 508
 509         /* This function is called when super block should be written back */
 510         if (wait)
 511                 err = nilfs_construct_segment(sb);
 512
 513         down_write(&nilfs->ns_sem);
 514         if (nilfs_sb_dirty(nilfs)) {
 515                 sbp = nilfs_prepare_super(sb, nilfs_sb_will_flip(nilfs));
 516                 if (likely(sbp)) {
 517                         nilfs_set_log_cursor(sbp[0], nilfs);
 518                         nilfs_commit_super(sb, NILFS_SB_COMMIT);
 519                 }
 520         }
 521         up_write(&nilfs->ns_sem);
 522
 523         if (!err)
 524                 err = nilfs_flush_device(nilfs);
 525
 526         return err;
 527 }
 528
 529 int nilfs_attach_checkpoint(struct super_block *sb, __u64 cno, int curr_mnt,
 530                             struct nilfs_root **rootp)
 531 {
 532         struct the_nilfs *nilfs = sb->s_fs_info;
 533         struct nilfs_root *root;
 534         struct nilfs_checkpoint *raw_cp;
 535         struct buffer_head *bh_cp;
 536         int err = -ENOMEM;
 537
 538         root = nilfs_find_or_create_root(
 539                 nilfs, curr_mnt ? NILFS_CPTREE_CURRENT_CNO : cno);
 540         if (!root)
 541                 return err;
 542
 543         if (root->ifile)
 544                 goto reuse; /* already attached checkpoint */
 545
 546         down_read(&nilfs->ns_segctor_sem);
 547         err = nilfs_cpfile_get_checkpoint(nilfs->ns_cpfile, cno, 0, &raw_cp,
 548                                           &bh_cp);
 549         up_read(&nilfs->ns_segctor_sem);
 550         if (unlikely(err)) {
 551                 if (err == -ENOENT || err == -EINVAL) {
 552                         printk(KERN_ERR
 553                                "NILFS: Invalid checkpoint "
 554                                "(checkpoint number=%llu)\n",
 555                                (unsigned long long)cno);
 556                         err = -EINVAL;
 557                 }
 558                 goto failed;
 559         }
 560
 561         err = nilfs_ifile_read(sb, root, nilfs->ns_inode_size,
 562                                &raw_cp->cp_ifile_inode, &root->ifile);
 563         if (err)
 564                 goto failed_bh;
 565
 566         atomic64_set(&root->inodes_count,
 567                         le64_to_cpu(raw_cp->cp_inodes_count));
 568         atomic64_set(&root->blocks_count,
 569                         le64_to_cpu(raw_cp->cp_blocks_count));
 570
 571         nilfs_cpfile_put_checkpoint(nilfs->ns_cpfile, cno, bh_cp);
 572
 573  reuse:
 574         *rootp = root;
 575         return 0;
 576
 577  failed_bh:
 578         nilfs_cpfile_put_checkpoint(nilfs->ns_cpfile, cno, bh_cp);
 579  failed:
 580         nilfs_put_root(root);
 581
 582         return err;
 583 }
 584
 585 static int nilfs_freeze(struct super_block *sb)
 586 {
 587         struct the_nilfs *nilfs = sb->s_fs_info;
 588         int err;
 589
 590         if (sb->s_flags & MS_RDONLY)
 591                 return 0;
 592
 593         /* Mark super block clean */
 594         down_write(&nilfs->ns_sem);
 595         err = nilfs_cleanup_super(sb);
 596         up_write(&nilfs->ns_sem);
 597         return err;
 598 }
 599
 600 static int nilfs_unfreeze(struct super_block *sb)
 601 {
 602         struct the_nilfs *nilfs = sb->s_fs_info;
 603
 604         if (sb->s_flags & MS_RDONLY)
 605                 return 0;
 606
 607         down_write(&nilfs->ns_sem);
 608         nilfs_setup_super(sb, false);
 609         up_write(&nilfs->ns_sem);
 610         return 0;
 611 }
 612
 613 static int nilfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 614 {
 615         struct super_block *sb = dentry->d_sb;
 616         struct nilfs_root *root = NILFS_I(d_inode(dentry))->i_root;
 617         struct the_nilfs *nilfs = root->nilfs;
 618         u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
 619         unsigned long long blocks;
 620         unsigned long overhead;
 621         unsigned long nrsvblocks;
 622         sector_t nfreeblocks;
 623         u64 nmaxinodes, nfreeinodes;
 624         int err;
 625
 626         /*
 627          * Compute all of the segment blocks
 628          *
 629          * The blocks before first segment and after last segment
 630          * are excluded.
 631          */
 632         blocks = nilfs->ns_blocks_per_segment * nilfs->ns_nsegments
 633                 - nilfs->ns_first_data_block;
 634         nrsvblocks = nilfs->ns_nrsvsegs * nilfs->ns_blocks_per_segment;
 635
 636         /*
 637          * Compute the overhead
 638          *
 639          * When distributing meta data blocks outside segment structure,
 640          * We must count them as the overhead.
 641          */
 642         overhead = 0;
 643
 644         err = nilfs_count_free_blocks(nilfs, &nfreeblocks);
 645         if (unlikely(err))
 646                 return err;
 647
 648         err = nilfs_ifile_count_free_inodes(root->ifile,
 649                                             &nmaxinodes, &nfreeinodes);
 650         if (unlikely(err)) {
 651                 printk(KERN_WARNING
 652                         "NILFS warning: fail to count free inodes: err %d.\n",
 653                         err);
 654                 if (err == -ERANGE) {
 655                         /*
 656                          * If nilfs_palloc_count_max_entries() returns
 657                          * -ERANGE error code then we simply treat
 658                          * curent inodes count as maximum possible and
 659                          * zero as free inodes value.
 660                          */
 661                         nmaxinodes = atomic64_read(&root->inodes_count);
 662                         nfreeinodes = 0;
 663                         err = 0;
 664                 } else
 665                         return err;
 666         }
 667
 668         buf->f_type = NILFS_SUPER_MAGIC;
 669         buf->f_bsize = sb->s_blocksize;
 670         buf->f_blocks = blocks - overhead;
 671         buf->f_bfree = nfreeblocks;
 672         buf->f_bavail = (buf->f_bfree >= nrsvblocks) ?
 673                 (buf->f_bfree - nrsvblocks) : 0;
 674         buf->f_files = nmaxinodes;
 675         buf->f_ffree = nfreeinodes;
 676         buf->f_namelen = NILFS_NAME_LEN;
 677         buf->f_fsid.val[0] = (u32)id;
 678         buf->f_fsid.val[1] = (u32)(id >> 32);
 679
 680         return 0;
 681 }
 682
 683 static int nilfs_show_options(struct seq_file *seq, struct dentry *dentry)
 684 {
 685         struct super_block *sb = dentry->d_sb;
 686         struct the_nilfs *nilfs = sb->s_fs_info;
 687         struct nilfs_root *root = NILFS_I(d_inode(dentry))->i_root;
 688
 689         if (!nilfs_test_opt(nilfs, BARRIER))
 690                 seq_puts(seq, ",nobarrier");
 691         if (root->cno != NILFS_CPTREE_CURRENT_CNO)
 692                 seq_printf(seq, ",cp=%llu", (unsigned long long)root->cno);
 693         if (nilfs_test_opt(nilfs, ERRORS_PANIC))
 694                 seq_puts(seq, ",errors=panic");
 695         if (nilfs_test_opt(nilfs, ERRORS_CONT))
 696                 seq_puts(seq, ",errors=continue");
 697         if (nilfs_test_opt(nilfs, STRICT_ORDER))
 698                 seq_puts(seq, ",order=strict");
 699         if (nilfs_test_opt(nilfs, NORECOVERY))
 700                 seq_puts(seq, ",norecovery");
 701         if (nilfs_test_opt(nilfs, DISCARD))
 702                 seq_puts(seq, ",discard");
 703
 704         return 0;
 705 }
 706
 707 static const struct super_operations nilfs_sops = {
 708         .alloc_inode    = nilfs_alloc_inode,
 709         .destroy_inode  = nilfs_destroy_inode,
 710         .dirty_inode    = nilfs_dirty_inode,
 711         .evict_inode    = nilfs_evict_inode,
 712         .put_super      = nilfs_put_super,
 713         .sync_fs        = nilfs_sync_fs,
 714         .freeze_fs      = nilfs_freeze,
 715         .unfreeze_fs    = nilfs_unfreeze,
 716         .statfs         = nilfs_statfs,
 717         .remount_fs     = nilfs_remount,
 718         .show_options = nilfs_show_options
 719 };
 720
 721 enum {
 722         Opt_err_cont, Opt_err_panic, Opt_err_ro,
 723         Opt_barrier, Opt_nobarrier, Opt_snapshot, Opt_order, Opt_norecovery,
 724         Opt_discard, Opt_nodiscard, Opt_err,
 725 };
 726
 727 static match_table_t tokens = {
 728         {Opt_err_cont, "errors=continue"},
 729         {Opt_err_panic, "errors=panic"},
 730         {Opt_err_ro, "errors=remount-ro"},
 731         {Opt_barrier, "barrier"},
 732         {Opt_nobarrier, "nobarrier"},
 733         {Opt_snapshot, "cp=%u"},
 734         {Opt_order, "order=%s"},
 735         {Opt_norecovery, "norecovery"},
 736         {Opt_discard, "discard"},
 737         {Opt_nodiscard, "nodiscard"},
 738         {Opt_err, NULL}
 739 };
 740
 741 static int parse_options(char *options, struct super_block *sb, int is_remount)
 742 {
 743         struct the_nilfs *nilfs = sb->s_fs_info;
 744         char *p;
 745         substring_t args[MAX_OPT_ARGS];
 746
 747         if (!options)
 748                 return 1;
 749
 750         while ((p = strsep(&options, ",")) != NULL) {
 751                 int token;
 752                 if (!*p)
 753                         continue;
 754
 755                 token = match_token(p, tokens, args);
 756                 switch (token) {
 757                 case Opt_barrier:
 758                         nilfs_set_opt(nilfs, BARRIER);
 759                         break;
 760                 case Opt_nobarrier:
 761                         nilfs_clear_opt(nilfs, BARRIER);
 762                         break;
 763                 case Opt_order:
 764                         if (strcmp(args[0].from, "relaxed") == 0)
 765                                 /* Ordered data semantics */
 766                                 nilfs_clear_opt(nilfs, STRICT_ORDER);
 767                         else if (strcmp(args[0].from, "strict") == 0)
 768                                 /* Strict in-order semantics */
 769                                 nilfs_set_opt(nilfs, STRICT_ORDER);
 770                         else
 771                                 return 0;
 772                         break;
 773                 case Opt_err_panic:
 774                         nilfs_write_opt(nilfs, ERROR_MODE, ERRORS_PANIC);
 775                         break;
 776                 case Opt_err_ro:
 777                         nilfs_write_opt(nilfs, ERROR_MODE, ERRORS_RO);
 778                         break;
 779                 case Opt_err_cont:
 780                         nilfs_write_opt(nilfs, ERROR_MODE, ERRORS_CONT);
 781                         break;
 782                 case Opt_snapshot:
 783                         if (is_remount) {
 784                                 printk(KERN_ERR
 785                                        "NILFS: \"%s\" option is invalid "
 786                                        "for remount.\n", p);
 787                                 return 0;
 788                         }
 789                         break;
 790                 case Opt_norecovery:
 791                         nilfs_set_opt(nilfs, NORECOVERY);
 792                         break;
 793                 case Opt_discard:
 794                         nilfs_set_opt(nilfs, DISCARD);
 795                         break;
 796                 case Opt_nodiscard:
 797                         nilfs_clear_opt(nilfs, DISCARD);
 798                         break;
 799                 default:
 800                         printk(KERN_ERR
 801                                "NILFS: Unrecognized mount option \"%s\"\n", p);
 802                         return 0;
 803                 }
 804         }
 805         return 1;
 806 }
 807
 808 static inline void
 809 nilfs_set_default_options(struct super_block *sb,
 810                           struct nilfs_super_block *sbp)
 811 {
 812         struct the_nilfs *nilfs = sb->s_fs_info;
 813
 814         nilfs->ns_mount_opt =
 815                 NILFS_MOUNT_ERRORS_RO | NILFS_MOUNT_BARRIER;
 816 }
 817
 818 static int nilfs_setup_super(struct super_block *sb, int is_mount)
 819 {
 820         struct the_nilfs *nilfs = sb->s_fs_info;
 821         struct nilfs_super_block **sbp;
 822         int max_mnt_count;
 823         int mnt_count;
 824
 825         /* nilfs->ns_sem must be locked by the caller. */
 826         sbp = nilfs_prepare_super(sb, 0);
 827         if (!sbp)
 828                 return -EIO;
 829
 830         if (!is_mount)
 831                 goto skip_mount_setup;
 832
 833         max_mnt_count = le16_to_cpu(sbp[0]->s_max_mnt_count);
 834         mnt_count = le16_to_cpu(sbp[0]->s_mnt_count);
 835
 836         if (nilfs->ns_mount_state & NILFS_ERROR_FS) {
 837                 printk(KERN_WARNING
 838                        "NILFS warning: mounting fs with errors\n");
 839 #if 0
 840         } else if (max_mnt_count >= 0 && mnt_count >= max_mnt_count) {
 841                 printk(KERN_WARNING
 842                        "NILFS warning: maximal mount count reached\n");
 843 #endif
 844         }
 845         if (!max_mnt_count)
 846                 sbp[0]->s_max_mnt_count = cpu_to_le16(NILFS_DFL_MAX_MNT_COUNT);
 847
 848         sbp[0]->s_mnt_count = cpu_to_le16(mnt_count + 1);
 849         sbp[0]->s_mtime = cpu_to_le64(get_seconds());
 850
 851 skip_mount_setup:
 852         sbp[0]->s_state =
 853                 cpu_to_le16(le16_to_cpu(sbp[0]->s_state) & ~NILFS_VALID_FS);
 854         /* synchronize sbp[1] with sbp[0] */
 855         if (sbp[1])
 856                 memcpy(sbp[1], sbp[0], nilfs->ns_sbsize);
 857         return nilfs_commit_super(sb, NILFS_SB_COMMIT_ALL);
 858 }
 859
 860 struct nilfs_super_block *nilfs_read_super_block(struct super_block *sb,
 861                                                  u64 pos, int blocksize,
 862                                                  struct buffer_head **pbh)
 863 {
 864         unsigned long long sb_index = pos;
 865         unsigned long offset;
 866
 867         offset = do_div(sb_index, blocksize);
 868         *pbh = sb_bread(sb, sb_index);
 869         if (!*pbh)
 870                 return NULL;
 871         return (struct nilfs_super_block *)((char *)(*pbh)->b_data + offset);
 872 }
 873
 874 int nilfs_store_magic_and_option(struct super_block *sb,
 875                                  struct nilfs_super_block *sbp,
 876                                  char *data)
 877 {
 878         struct the_nilfs *nilfs = sb->s_fs_info;
 879
 880         sb->s_magic = le16_to_cpu(sbp->s_magic);
 881
 882         /* FS independent flags */
 883 #ifdef NILFS_ATIME_DISABLE
 884         sb->s_flags |= MS_NOATIME;
 885 #endif
 886
 887         nilfs_set_default_options(sb, sbp);
 888
 889         nilfs->ns_resuid = le16_to_cpu(sbp->s_def_resuid);
 890         nilfs->ns_resgid = le16_to_cpu(sbp->s_def_resgid);
 891         nilfs->ns_interval = le32_to_cpu(sbp->s_c_interval);
 892         nilfs->ns_watermark = le32_to_cpu(sbp->s_c_block_max);
 893
 894         return !parse_options(data, sb, 0) ? -EINVAL : 0 ;
 895 }
 896
 897 int nilfs_check_feature_compatibility(struct super_block *sb,
 898                                       struct nilfs_super_block *sbp)
 899 {
 900         __u64 features;
 901
 902         features = le64_to_cpu(sbp->s_feature_incompat) &
 903                 ~NILFS_FEATURE_INCOMPAT_SUPP;
 904         if (features) {
 905                 printk(KERN_ERR "NILFS: couldn't mount because of unsupported "
 906                        "optional features (%llx)\n",
 907                        (unsigned long long)features);
 908                 return -EINVAL;
 909         }
 910         features = le64_to_cpu(sbp->s_feature_compat_ro) &
 911                 ~NILFS_FEATURE_COMPAT_RO_SUPP;
 912         if (!(sb->s_flags & MS_RDONLY) && features) {
 913                 printk(KERN_ERR "NILFS: couldn't mount RDWR because of "
 914                        "unsupported optional features (%llx)\n",
 915                        (unsigned long long)features);
 916                 return -EINVAL;
 917         }
 918         return 0;
 919 }
 920
 921 static int nilfs_get_root_dentry(struct super_block *sb,
 922                                  struct nilfs_root *root,
 923                                  struct dentry **root_dentry)
 924 {
 925         struct inode *inode;
 926         struct dentry *dentry;
 927         int ret = 0;
 928
 929         inode = nilfs_iget(sb, root, NILFS_ROOT_INO);
 930         if (IS_ERR(inode)) {
 931                 printk(KERN_ERR "NILFS: get root inode failed\n");
 932                 ret = PTR_ERR(inode);
 933                 goto out;
 934         }
 935         if (!S_ISDIR(inode->i_mode) || !inode->i_blocks || !inode->i_size) {
 936                 iput(inode);
 937                 printk(KERN_ERR "NILFS: corrupt root inode.\n");
 938                 ret = -EINVAL;
 939                 goto out;
 940         }
 941
 942         if (root->cno == NILFS_CPTREE_CURRENT_CNO) {
 943                 dentry = d_find_alias(inode);
 944                 if (!dentry) {
 945                         dentry = d_make_root(inode);
 946                         if (!dentry) {
 947                                 ret = -ENOMEM;
 948                                 goto failed_dentry;
 949                         }
 950                 } else {
 951                         iput(inode);
 952                 }
 953         } else {
 954                 dentry = d_obtain_root(inode);
 955                 if (IS_ERR(dentry)) {
 956                         ret = PTR_ERR(dentry);
 957                         goto failed_dentry;
 958                 }
 959         }
 960         *root_dentry = dentry;
 961  out:
 962         return ret;
 963
 964  failed_dentry:
 965         printk(KERN_ERR "NILFS: get root dentry failed\n");
 966         goto out;
 967 }
 968
 969 static int nilfs_attach_snapshot(struct super_block *s, __u64 cno,
 970                                  struct dentry **root_dentry)
 971 {
 972         struct the_nilfs *nilfs = s->s_fs_info;
 973         struct nilfs_root *root;
 974         int ret;
 975
 976         mutex_lock(&nilfs->ns_snapshot_mount_mutex);
 977
 978         down_read(&nilfs->ns_segctor_sem);
 979         ret = nilfs_cpfile_is_snapshot(nilfs->ns_cpfile, cno);
 980         up_read(&nilfs->ns_segctor_sem);
 981         if (ret < 0) {
 982                 ret = (ret == -ENOENT) ? -EINVAL : ret;
 983                 goto out;
 984         } else if (!ret) {
 985                 printk(KERN_ERR "NILFS: The specified checkpoint is "
 986                        "not a snapshot (checkpoint number=%llu).\n",
 987                        (unsigned long long)cno);
 988                 ret = -EINVAL;
 989                 goto out;
 990         }
 991
 992         ret = nilfs_attach_checkpoint(s, cno, false, &root);
 993         if (ret) {
 994                 printk(KERN_ERR "NILFS: error loading snapshot "
 995                        "(checkpoint number=%llu).\n",
 996                (unsigned long long)cno);
 997                 goto out;
 998         }
 999         ret = nilfs_get_root_dentry(s, root, root_dentry);
1000         nilfs_put_root(root);
1001  out:
1002         mutex_unlock(&nilfs->ns_snapshot_mount_mutex);
1003         return ret;
1004 }
1005
1006 /**
1007  * nilfs_tree_is_busy() - try to shrink dentries of a checkpoint
1008  * @root_dentry: root dentry of the tree to be shrunk
1009  *
1010  * This function returns true if the tree was in-use.
1011  */
1012 static bool nilfs_tree_is_busy(struct dentry *root_dentry)
1013 {
1014         shrink_dcache_parent(root_dentry);
1015         return d_count(root_dentry) > 1;
1016 }
1017
1018 int nilfs_checkpoint_is_mounted(struct super_block *sb, __u64 cno)
1019 {
1020         struct the_nilfs *nilfs = sb->s_fs_info;
1021         struct nilfs_root *root;
1022         struct inode *inode;
1023         struct dentry *dentry;
1024         int ret;
1025
1026         if (cno > nilfs->ns_cno)
1027                 return false;
1028
1029         if (cno >= nilfs_last_cno(nilfs))
1030                 return true;    /* protect recent checkpoints */
1031
1032         ret = false;
1033         root = nilfs_lookup_root(nilfs, cno);
1034         if (root) {
1035                 inode = nilfs_ilookup(sb, root, NILFS_ROOT_INO);
1036                 if (inode) {
1037                         dentry = d_find_alias(inode);
1038                         if (dentry) {
1039                                 ret = nilfs_tree_is_busy(dentry);
1040                                 dput(dentry);
1041                         }
1042                         iput(inode);
1043                 }
1044                 nilfs_put_root(root);
1045         }
1046         return ret;
1047 }
1048
1049 /**
1050  * nilfs_fill_super() - initialize a super block instance
1051  * @sb: super_block
1052  * @data: mount options
1053  * @silent: silent mode flag
1054  *
1055  * This function is called exclusively by nilfs->ns_mount_mutex.
1056  * So, the recovery process is protected from other simultaneous mounts.
1057  */
1058 static int
1059 nilfs_fill_super(struct super_block *sb, void *data, int silent)
1060 {
1061         struct the_nilfs *nilfs;
1062         struct nilfs_root *fsroot;
1063         __u64 cno;
1064         int err;
1065
1066         nilfs = alloc_nilfs(sb->s_bdev);
1067         if (!nilfs)
1068                 return -ENOMEM;
1069
1070         sb->s_fs_info = nilfs;
1071
1072         err = init_nilfs(nilfs, sb, (char *)data);
1073         if (err)
1074                 goto failed_nilfs;
1075
1076         sb->s_op = &nilfs_sops;
1077         sb->s_export_op = &nilfs_export_ops;
1078         sb->s_root = NULL;
1079         sb->s_time_gran = 1;
1080         sb->s_max_links = NILFS_LINK_MAX;
1081
1082         sb->s_bdi = &bdev_get_queue(sb->s_bdev)->backing_dev_info;
1083
1084         err = load_nilfs(nilfs, sb);
1085         if (err)
1086                 goto failed_nilfs;
1087
1088         cno = nilfs_last_cno(nilfs);
1089         err = nilfs_attach_checkpoint(sb, cno, true, &fsroot);
1090         if (err) {
1091                 printk(KERN_ERR "NILFS: error loading last checkpoint "
1092                        "(checkpoint number=%llu).\n", (unsigned long long)cno);
1093                 goto failed_unload;
1094         }
1095
1096         if (!(sb->s_flags & MS_RDONLY)) {
1097                 err = nilfs_attach_log_writer(sb, fsroot);
1098                 if (err)
1099                         goto failed_checkpoint;
1100         }
1101
1102         err = nilfs_get_root_dentry(sb, fsroot, &sb->s_root);
1103         if (err)
1104                 goto failed_segctor;
1105
1106         nilfs_put_root(fsroot);
1107
1108         if (!(sb->s_flags & MS_RDONLY)) {
1109                 down_write(&nilfs->ns_sem);
1110                 nilfs_setup_super(sb, true);
1111                 up_write(&nilfs->ns_sem);
1112         }
1113
1114         return 0;
1115
1116  failed_segctor:
1117         nilfs_detach_log_writer(sb);
1118
1119  failed_checkpoint:
1120         nilfs_put_root(fsroot);
1121
1122  failed_unload:
1123         iput(nilfs->ns_sufile);
1124         iput(nilfs->ns_cpfile);
1125         iput(nilfs->ns_dat);
1126
1127  failed_nilfs:
1128         destroy_nilfs(nilfs);
1129         return err;
1130 }
1131
1132 static int nilfs_remount(struct super_block *sb, int *flags, char *data)
1133 {
1134         struct the_nilfs *nilfs = sb->s_fs_info;
1135         unsigned long old_sb_flags;
1136         unsigned long old_mount_opt;
1137         int err;
1138
1139         sync_filesystem(sb);
1140         old_sb_flags = sb->s_flags;
1141         old_mount_opt = nilfs->ns_mount_opt;
1142
1143         if (!parse_options(data, sb, 1)) {
1144                 err = -EINVAL;
1145                 goto restore_opts;
1146         }
1147         sb->s_flags = (sb->s_flags & ~MS_POSIXACL);
1148
1149         err = -EINVAL;
1150
1151         if (!nilfs_valid_fs(nilfs)) {
1152                 printk(KERN_WARNING "NILFS (device %s): couldn't "
1153                        "remount because the filesystem is in an "
1154                        "incomplete recovery state.\n", sb->s_id);
1155                 goto restore_opts;
1156         }
1157
1158         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
1159                 goto out;
1160         if (*flags & MS_RDONLY) {
1161                 /* Shutting down log writer */
1162                 nilfs_detach_log_writer(sb);
1163                 sb->s_flags |= MS_RDONLY;
1164
1165                 /*
1166                  * Remounting a valid RW partition RDONLY, so set
1167                  * the RDONLY flag and then mark the partition as valid again.
1168                  */
1169                 down_write(&nilfs->ns_sem);
1170                 nilfs_cleanup_super(sb);
1171                 up_write(&nilfs->ns_sem);
1172         } else {
1173                 __u64 features;
1174                 struct nilfs_root *root;
1175
1176                 /*
1177                  * Mounting a RDONLY partition read-write, so reread and
1178                  * store the current valid flag.  (It may have been changed
1179                  * by fsck since we originally mounted the partition.)
1180                  */
1181                 down_read(&nilfs->ns_sem);
1182                 features = le64_to_cpu(nilfs->ns_sbp[0]->s_feature_compat_ro) &
1183                         ~NILFS_FEATURE_COMPAT_RO_SUPP;
1184                 up_read(&nilfs->ns_sem);
1185                 if (features) {
1186                         printk(KERN_WARNING "NILFS (device %s): couldn't "
1187                                "remount RDWR because of unsupported optional "
1188                                "features (%llx)\n",
1189                                sb->s_id, (unsigned long long)features);
1190                         err = -EROFS;
1191                         goto restore_opts;
1192                 }
1193
1194                 sb->s_flags &= ~MS_RDONLY;
1195
1196                 root = NILFS_I(d_inode(sb->s_root))->i_root;
1197                 err = nilfs_attach_log_writer(sb, root);
1198                 if (err)
1199                         goto restore_opts;
1200
1201                 down_write(&nilfs->ns_sem);
1202                 nilfs_setup_super(sb, true);
1203                 up_write(&nilfs->ns_sem);
1204         }
1205  out:
1206         return 0;
1207
1208  restore_opts:
1209         sb->s_flags = old_sb_flags;
1210         nilfs->ns_mount_opt = old_mount_opt;
1211         return err;
1212 }
1213
1214 struct nilfs_super_data {
1215         struct block_device *bdev;
1216         __u64 cno;
1217         int flags;
1218 };
1219
1220 /**
1221  * nilfs_identify - pre-read mount options needed to identify mount instance
1222  * @data: mount options
1223  * @sd: nilfs_super_data
1224  */
1225 static int nilfs_identify(char *data, struct nilfs_super_data *sd)
1226 {
1227         char *p, *options = data;
1228         substring_t args[MAX_OPT_ARGS];
1229         int token;
1230         int ret = 0;
1231
1232         do {
1233                 p = strsep(&options, ",");
1234                 if (p != NULL && *p) {
1235                         token = match_token(p, tokens, args);
1236                         if (token == Opt_snapshot) {
1237                                 if (!(sd->flags & MS_RDONLY)) {
1238                                         ret++;
1239                                 } else {
1240                                         sd->cno = simple_strtoull(args[0].from,
1241                                                                   NULL, 0);
1242                                         /*
1243                                          * No need to see the end pointer;
1244                                          * match_token() has done syntax
1245                                          * checking.
1246                                          */
1247                                         if (sd->cno == 0)
1248                                                 ret++;
1249                                 }
1250                         }
1251                         if (ret)
1252                                 printk(KERN_ERR
1253                                        "NILFS: invalid mount option: %s\n", p);
1254                 }
1255                 if (!options)
1256                         break;
1257                 BUG_ON(options == data);
1258                 *(options - 1) = ',';
1259         } while (!ret);
1260         return ret;
1261 }
1262
1263 static int nilfs_set_bdev_super(struct super_block *s, void *data)
1264 {
1265         s->s_bdev = data;
1266         s->s_dev = s->s_bdev->bd_dev;
1267         return 0;
1268 }
1269
1270 static int nilfs_test_bdev_super(struct super_block *s, void *data)
1271 {
1272         return (void *)s->s_bdev == data;
1273 }
1274
1275 static struct dentry *
1276 nilfs_mount(struct file_system_type *fs_type, int flags,
1277              const char *dev_name, void *data)
1278 {
1279         struct nilfs_super_data sd;
1280         struct super_block *s;
1281         fmode_t mode = FMODE_READ | FMODE_EXCL;
1282         struct dentry *root_dentry;
1283         int err, s_new = false;
1284
1285         if (!(flags & MS_RDONLY))
1286                 mode |= FMODE_WRITE;
1287
1288         sd.bdev = blkdev_get_by_path(dev_name, mode, fs_type);
1289         if (IS_ERR(sd.bdev))
1290                 return ERR_CAST(sd.bdev);
1291
1292         sd.cno = 0;
1293         sd.flags = flags;
1294         if (nilfs_identify((char *)data, &sd)) {
1295                 err = -EINVAL;
1296                 goto failed;
1297         }
1298
1299         /*
1300          * once the super is inserted into the list by sget, s_umount
1301          * will protect the lockfs code from trying to start a snapshot
1302          * while we are mounting
1303          */
1304         mutex_lock(&sd.bdev->bd_fsfreeze_mutex);
1305         if (sd.bdev->bd_fsfreeze_count > 0) {
1306                 mutex_unlock(&sd.bdev->bd_fsfreeze_mutex);
1307                 err = -EBUSY;
1308                 goto failed;
1309         }
1310         s = sget(fs_type, nilfs_test_bdev_super, nilfs_set_bdev_super, flags,
1311                  sd.bdev);
1312         mutex_unlock(&sd.bdev->bd_fsfreeze_mutex);
1313         if (IS_ERR(s)) {
1314                 err = PTR_ERR(s);
1315                 goto failed;
1316         }
1317
1318         if (!s->s_root) {
1319                 s_new = true;
1320
1321                 /* New superblock instance created */
1322                 s->s_mode = mode;
1323                 snprintf(s->s_id, sizeof(s->s_id), "%pg", sd.bdev);
1324                 sb_set_blocksize(s, block_size(sd.bdev));
1325
1326                 err = nilfs_fill_super(s, data, flags & MS_SILENT ? 1 : 0);
1327                 if (err)
1328                         goto failed_super;
1329
1330                 s->s_flags |= MS_ACTIVE;
1331         } else if (!sd.cno) {
1332                 if (nilfs_tree_is_busy(s->s_root)) {
1333                         if ((flags ^ s->s_flags) & MS_RDONLY) {
1334                                 printk(KERN_ERR "NILFS: the device already "
1335                                        "has a %s mount.\n",
1336                                        (s->s_flags & MS_RDONLY) ?
1337                                        "read-only" : "read/write");
1338                                 err = -EBUSY;
1339                                 goto failed_super;
1340                         }
1341                 } else {
1342                         /*
1343                          * Try remount to setup mount states if the current
1344                          * tree is not mounted and only snapshots use this sb.
1345                          */
1346                         err = nilfs_remount(s, &flags, data);
1347                         if (err)
1348                                 goto failed_super;
1349                 }
1350         }
1351
1352         if (sd.cno) {
1353                 err = nilfs_attach_snapshot(s, sd.cno, &root_dentry);
1354                 if (err)
1355                         goto failed_super;
1356         } else {
1357                 root_dentry = dget(s->s_root);
1358         }
1359
1360         if (!s_new)
1361                 blkdev_put(sd.bdev, mode);
1362
1363         return root_dentry;
1364
1365  failed_super:
1366         deactivate_locked_super(s);
1367
1368  failed:
1369         if (!s_new)
1370                 blkdev_put(sd.bdev, mode);
1371         return ERR_PTR(err);
1372 }
1373
1374 struct file_system_type nilfs_fs_type = {
1375         .owner    = THIS_MODULE,
1376         .name     = "nilfs2",
1377         .mount    = nilfs_mount,
1378         .kill_sb  = kill_block_super,
1379         .fs_flags = FS_REQUIRES_DEV,
1380 };
1381 MODULE_ALIAS_FS("nilfs2");
1382
1383 static void nilfs_inode_init_once(void *obj)
1384 {
1385         struct nilfs_inode_info *ii = obj;
1386
1387         INIT_LIST_HEAD(&ii->i_dirty);
1388 #ifdef CONFIG_NILFS_XATTR
1389         init_rwsem(&ii->xattr_sem);
1390 #endif
1391         address_space_init_once(&ii->i_btnode_cache);
1392         ii->i_bmap = &ii->i_bmap_data;
1393         inode_init_once(&ii->vfs_inode);
1394 }
1395
1396 static void nilfs_segbuf_init_once(void *obj)
1397 {
1398         memset(obj, 0, sizeof(struct nilfs_segment_buffer));
1399 }
1400
1401 static void nilfs_destroy_cachep(void)
1402 {
1403         /*
1404          * Make sure all delayed rcu free inodes are flushed before we
1405          * destroy cache.
1406          */
1407         rcu_barrier();
1408
1409         kmem_cache_destroy(nilfs_inode_cachep);
1410         kmem_cache_destroy(nilfs_transaction_cachep);
1411         kmem_cache_destroy(nilfs_segbuf_cachep);
1412         kmem_cache_destroy(nilfs_btree_path_cache);
1413 }
1414
1415 static int __init nilfs_init_cachep(void)
1416 {
1417         nilfs_inode_cachep = kmem_cache_create("nilfs2_inode_cache",
1418                         sizeof(struct nilfs_inode_info), 0,
1419                         SLAB_RECLAIM_ACCOUNT|SLAB_ACCOUNT,
1420                         nilfs_inode_init_once);
1421         if (!nilfs_inode_cachep)
1422                 goto fail;
1423
1424         nilfs_transaction_cachep = kmem_cache_create("nilfs2_transaction_cache",
1425                         sizeof(struct nilfs_transaction_info), 0,
1426                         SLAB_RECLAIM_ACCOUNT, NULL);
1427         if (!nilfs_transaction_cachep)
1428                 goto fail;
1429
1430         nilfs_segbuf_cachep = kmem_cache_create("nilfs2_segbuf_cache",
1431                         sizeof(struct nilfs_segment_buffer), 0,
1432                         SLAB_RECLAIM_ACCOUNT, nilfs_segbuf_init_once);
1433         if (!nilfs_segbuf_cachep)
1434                 goto fail;
1435
1436         nilfs_btree_path_cache = kmem_cache_create("nilfs2_btree_path_cache",
1437                         sizeof(struct nilfs_btree_path) * NILFS_BTREE_LEVEL_MAX,
1438                         0, 0, NULL);
1439         if (!nilfs_btree_path_cache)
1440                 goto fail;
1441
1442         return 0;
1443
1444 fail:
1445         nilfs_destroy_cachep();
1446         return -ENOMEM;
1447 }
1448
1449 static int __init init_nilfs_fs(void)
1450 {
1451         int err;
1452
1453         err = nilfs_init_cachep();
1454         if (err)
1455                 goto fail;
1456
1457         err = nilfs_sysfs_init();
1458         if (err)
1459                 goto free_cachep;
1460
1461         err = register_filesystem(&nilfs_fs_type);
1462         if (err)
1463                 goto deinit_sysfs_entry;
1464
1465         printk(KERN_INFO "NILFS version 2 loaded\n");
1466         return 0;
1467
1468 deinit_sysfs_entry:
1469         nilfs_sysfs_exit();
1470 free_cachep:
1471         nilfs_destroy_cachep();
1472 fail:
1473         return err;
1474 }
1475
1476 static void __exit exit_nilfs_fs(void)
1477 {
1478         nilfs_destroy_cachep();
1479         nilfs_sysfs_exit();
1480         unregister_filesystem(&nilfs_fs_type);
1481 }
1482
1483 module_init(init_nilfs_fs)
1484 module_exit(exit_nilfs_fs)