fs/nilfs2/super.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * super.c - NILFS module and super block management.
   4  *
   5  * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
   6  *
   7  * Written by Ryusuke Konishi.
   8  */
   9 /*
  10  *  linux/fs/ext2/super.c
  11  *
  12  * Copyright (C) 1992, 1993, 1994, 1995
  13  * Remy Card (card@masi.ibp.fr)
  14  * Laboratoire MASI - Institut Blaise Pascal
  15  * Universite Pierre et Marie Curie (Paris VI)
  16  *
  17  *  from
  18  *
  19  *  linux/fs/minix/inode.c
  20  *
  21  *  Copyright (C) 1991, 1992  Linus Torvalds
  22  *
  23  *  Big-endian to little-endian byte-swapping/bitmaps by
  24  *        David S. Miller (davem@caip.rutgers.edu), 1995
  25  */
  26
  27 #include <linux/module.h>
  28 #include <linux/string.h>
  29 #include <linux/slab.h>
  30 #include <linux/init.h>
  31 #include <linux/blkdev.h>
  32 #include <linux/parser.h>
  33 #include <linux/crc32.h>
  34 #include <linux/vfs.h>
  35 #include <linux/writeback.h>
  36 #include <linux/seq_file.h>
  37 #include <linux/mount.h>
  38 #include "nilfs.h"
  39 #include "export.h"
  40 #include "mdt.h"
  41 #include "alloc.h"
  42 #include "btree.h"
  43 #include "btnode.h"
  44 #include "page.h"
  45 #include "cpfile.h"
  46 #include "sufile.h" /* nilfs_sufile_resize(), nilfs_sufile_set_alloc_range() */
  47 #include "ifile.h"
  48 #include "dat.h"
  49 #include "segment.h"
  50 #include "segbuf.h"
  51
  52 MODULE_AUTHOR("NTT Corp.");
  53 MODULE_DESCRIPTION("A New Implementation of the Log-structured Filesystem "
  54                    "(NILFS)");
  55 MODULE_LICENSE("GPL");
  56
  57 static struct kmem_cache *nilfs_inode_cachep;
  58 struct kmem_cache *nilfs_transaction_cachep;
  59 struct kmem_cache *nilfs_segbuf_cachep;
  60 struct kmem_cache *nilfs_btree_path_cache;
  61
  62 static int nilfs_setup_super(struct super_block *sb, int is_mount);
  63 static int nilfs_remount(struct super_block *sb, int *flags, char *data);
  64
  65 void __nilfs_msg(struct super_block *sb, const char *fmt, ...)
  66 {
  67         struct va_format vaf;
  68         va_list args;
  69         int level;
  70
  71         va_start(args, fmt);
  72
  73         level = printk_get_level(fmt);
  74         vaf.fmt = printk_skip_level(fmt);
  75         vaf.va = &args;
  76
  77         if (sb)
  78                 printk("%c%cNILFS (%s): %pV\n",
  79                        KERN_SOH_ASCII, level, sb->s_id, &vaf);
  80         else
  81                 printk("%c%cNILFS: %pV\n",
  82                        KERN_SOH_ASCII, level, &vaf);
  83
  84         va_end(args);
  85 }
  86
  87 static void nilfs_set_error(struct super_block *sb)
  88 {
  89         struct the_nilfs *nilfs = sb->s_fs_info;
  90         struct nilfs_super_block **sbp;
  91
  92         down_write(&nilfs->ns_sem);
  93         if (!(nilfs->ns_mount_state & NILFS_ERROR_FS)) {
  94                 nilfs->ns_mount_state |= NILFS_ERROR_FS;
  95                 sbp = nilfs_prepare_super(sb, 0);
  96                 if (likely(sbp)) {
  97                         sbp[0]->s_state |= cpu_to_le16(NILFS_ERROR_FS);
  98                         if (sbp[1])
  99                                 sbp[1]->s_state |= cpu_to_le16(NILFS_ERROR_FS);
 100                         nilfs_commit_super(sb, NILFS_SB_COMMIT_ALL);
 101                 }
 102         }
 103         up_write(&nilfs->ns_sem);
 104 }
 105
 106 /**
 107  * __nilfs_error() - report failure condition on a filesystem
 108  *
 109  * __nilfs_error() sets an ERROR_FS flag on the superblock as well as
 110  * reporting an error message.  This function should be called when
 111  * NILFS detects incoherences or defects of meta data on disk.
 112  *
 113  * This implements the body of nilfs_error() macro.  Normally,
 114  * nilfs_error() should be used.  As for sustainable errors such as a
 115  * single-shot I/O error, nilfs_err() should be used instead.
 116  *
 117  * Callers should not add a trailing newline since this will do it.
 118  */
 119 void __nilfs_error(struct super_block *sb, const char *function,
 120                    const char *fmt, ...)
 121 {
 122         struct the_nilfs *nilfs = sb->s_fs_info;
 123         struct va_format vaf;
 124         va_list args;
 125
 126         va_start(args, fmt);
 127
 128         vaf.fmt = fmt;
 129         vaf.va = &args;
 130
 131         printk(KERN_CRIT "NILFS error (device %s): %s: %pV\n",
 132                sb->s_id, function, &vaf);
 133
 134         va_end(args);
 135
 136         if (!sb_rdonly(sb)) {
 137                 nilfs_set_error(sb);
 138
 139                 if (nilfs_test_opt(nilfs, ERRORS_RO)) {
 140                         printk(KERN_CRIT "Remounting filesystem read-only\n");
 141                         sb->s_flags |= SB_RDONLY;
 142                 }
 143         }
 144
 145         if (nilfs_test_opt(nilfs, ERRORS_PANIC))
 146                 panic("NILFS (device %s): panic forced after error\n",
 147                       sb->s_id);
 148 }
 149
 150 struct inode *nilfs_alloc_inode(struct super_block *sb)
 151 {
 152         struct nilfs_inode_info *ii;
 153
 154         ii = kmem_cache_alloc(nilfs_inode_cachep, GFP_NOFS);
 155         if (!ii)
 156                 return NULL;
 157         ii->i_bh = NULL;
 158         ii->i_state = 0;
 159         ii->i_cno = 0;
 160         ii->i_assoc_inode = NULL;
 161         ii->i_bmap = &ii->i_bmap_data;
 162         return &ii->vfs_inode;
 163 }
 164
 165 static void nilfs_free_inode(struct inode *inode)
 166 {
 167         if (nilfs_is_metadata_file_inode(inode))
 168                 nilfs_mdt_destroy(inode);
 169
 170         kmem_cache_free(nilfs_inode_cachep, NILFS_I(inode));
 171 }
 172
 173 static int nilfs_sync_super(struct super_block *sb, int flag)
 174 {
 175         struct the_nilfs *nilfs = sb->s_fs_info;
 176         int err;
 177
 178  retry:
 179         set_buffer_dirty(nilfs->ns_sbh[0]);
 180         if (nilfs_test_opt(nilfs, BARRIER)) {
 181                 err = __sync_dirty_buffer(nilfs->ns_sbh[0],
 182                                           REQ_SYNC | REQ_PREFLUSH | REQ_FUA);
 183         } else {
 184                 err = sync_dirty_buffer(nilfs->ns_sbh[0]);
 185         }
 186
 187         if (unlikely(err)) {
 188                 nilfs_err(sb, "unable to write superblock: err=%d", err);
 189                 if (err == -EIO && nilfs->ns_sbh[1]) {
 190                         /*
 191                          * sbp[0] points to newer log than sbp[1],
 192                          * so copy sbp[0] to sbp[1] to take over sbp[0].
 193                          */
 194                         memcpy(nilfs->ns_sbp[1], nilfs->ns_sbp[0],
 195                                nilfs->ns_sbsize);
 196                         nilfs_fall_back_super_block(nilfs);
 197                         goto retry;
 198                 }
 199         } else {
 200                 struct nilfs_super_block *sbp = nilfs->ns_sbp[0];
 201
 202                 nilfs->ns_sbwcount++;
 203
 204                 /*
 205                  * The latest segment becomes trailable from the position
 206                  * written in superblock.
 207                  */
 208                 clear_nilfs_discontinued(nilfs);
 209
 210                 /* update GC protection for recent segments */
 211                 if (nilfs->ns_sbh[1]) {
 212                         if (flag == NILFS_SB_COMMIT_ALL) {
 213                                 set_buffer_dirty(nilfs->ns_sbh[1]);
 214                                 if (sync_dirty_buffer(nilfs->ns_sbh[1]) < 0)
 215                                         goto out;
 216                         }
 217                         if (le64_to_cpu(nilfs->ns_sbp[1]->s_last_cno) <
 218                             le64_to_cpu(nilfs->ns_sbp[0]->s_last_cno))
 219                                 sbp = nilfs->ns_sbp[1];
 220                 }
 221
 222                 spin_lock(&nilfs->ns_last_segment_lock);
 223                 nilfs->ns_prot_seq = le64_to_cpu(sbp->s_last_seq);
 224                 spin_unlock(&nilfs->ns_last_segment_lock);
 225         }
 226  out:
 227         return err;
 228 }
 229
 230 void nilfs_set_log_cursor(struct nilfs_super_block *sbp,
 231                           struct the_nilfs *nilfs)
 232 {
 233         sector_t nfreeblocks;
 234
 235         /* nilfs->ns_sem must be locked by the caller. */
 236         nilfs_count_free_blocks(nilfs, &nfreeblocks);
 237         sbp->s_free_blocks_count = cpu_to_le64(nfreeblocks);
 238
 239         spin_lock(&nilfs->ns_last_segment_lock);
 240         sbp->s_last_seq = cpu_to_le64(nilfs->ns_last_seq);
 241         sbp->s_last_pseg = cpu_to_le64(nilfs->ns_last_pseg);
 242         sbp->s_last_cno = cpu_to_le64(nilfs->ns_last_cno);
 243         spin_unlock(&nilfs->ns_last_segment_lock);
 244 }
 245
 246 struct nilfs_super_block **nilfs_prepare_super(struct super_block *sb,
 247                                                int flip)
 248 {
 249         struct the_nilfs *nilfs = sb->s_fs_info;
 250         struct nilfs_super_block **sbp = nilfs->ns_sbp;
 251
 252         /* nilfs->ns_sem must be locked by the caller. */
 253         if (sbp[0]->s_magic != cpu_to_le16(NILFS_SUPER_MAGIC)) {
 254                 if (sbp[1] &&
 255                     sbp[1]->s_magic == cpu_to_le16(NILFS_SUPER_MAGIC)) {
 256                         memcpy(sbp[0], sbp[1], nilfs->ns_sbsize);
 257                 } else {
 258                         nilfs_crit(sb, "superblock broke");
 259                         return NULL;
 260                 }
 261         } else if (sbp[1] &&
 262                    sbp[1]->s_magic != cpu_to_le16(NILFS_SUPER_MAGIC)) {
 263                 memcpy(sbp[1], sbp[0], nilfs->ns_sbsize);
 264         }
 265
 266         if (flip && sbp[1])
 267                 nilfs_swap_super_block(nilfs);
 268
 269         return sbp;
 270 }
 271
 272 int nilfs_commit_super(struct super_block *sb, int flag)
 273 {
 274         struct the_nilfs *nilfs = sb->s_fs_info;
 275         struct nilfs_super_block **sbp = nilfs->ns_sbp;
 276         time64_t t;
 277
 278         /* nilfs->ns_sem must be locked by the caller. */
 279         t = ktime_get_real_seconds();
 280         nilfs->ns_sbwtime = t;
 281         sbp[0]->s_wtime = cpu_to_le64(t);
 282         sbp[0]->s_sum = 0;
 283         sbp[0]->s_sum = cpu_to_le32(crc32_le(nilfs->ns_crc_seed,
 284                                              (unsigned char *)sbp[0],
 285                                              nilfs->ns_sbsize));
 286         if (flag == NILFS_SB_COMMIT_ALL && sbp[1]) {
 287                 sbp[1]->s_wtime = sbp[0]->s_wtime;
 288                 sbp[1]->s_sum = 0;
 289                 sbp[1]->s_sum = cpu_to_le32(crc32_le(nilfs->ns_crc_seed,
 290                                             (unsigned char *)sbp[1],
 291                                             nilfs->ns_sbsize));
 292         }
 293         clear_nilfs_sb_dirty(nilfs);
 294         nilfs->ns_flushed_device = 1;
 295         /* make sure store to ns_flushed_device cannot be reordered */
 296         smp_wmb();
 297         return nilfs_sync_super(sb, flag);
 298 }
 299
 300 /**
 301  * nilfs_cleanup_super() - write filesystem state for cleanup
 302  * @sb: super block instance to be unmounted or degraded to read-only
 303  *
 304  * This function restores state flags in the on-disk super block.
 305  * This will set "clean" flag (i.e. NILFS_VALID_FS) unless the
 306  * filesystem was not clean previously.
 307  */
 308 int nilfs_cleanup_super(struct super_block *sb)
 309 {
 310         struct the_nilfs *nilfs = sb->s_fs_info;
 311         struct nilfs_super_block **sbp;
 312         int flag = NILFS_SB_COMMIT;
 313         int ret = -EIO;
 314
 315         sbp = nilfs_prepare_super(sb, 0);
 316         if (sbp) {
 317                 sbp[0]->s_state = cpu_to_le16(nilfs->ns_mount_state);
 318                 nilfs_set_log_cursor(sbp[0], nilfs);
 319                 if (sbp[1] && sbp[0]->s_last_cno == sbp[1]->s_last_cno) {
 320                         /*
 321                          * make the "clean" flag also to the opposite
 322                          * super block if both super blocks point to
 323                          * the same checkpoint.
 324                          */
 325                         sbp[1]->s_state = sbp[0]->s_state;
 326                         flag = NILFS_SB_COMMIT_ALL;
 327                 }
 328                 ret = nilfs_commit_super(sb, flag);
 329         }
 330         return ret;
 331 }
 332
 333 /**
 334  * nilfs_move_2nd_super - relocate secondary super block
 335  * @sb: super block instance
 336  * @sb2off: new offset of the secondary super block (in bytes)
 337  */
 338 static int nilfs_move_2nd_super(struct super_block *sb, loff_t sb2off)
 339 {
 340         struct the_nilfs *nilfs = sb->s_fs_info;
 341         struct buffer_head *nsbh;
 342         struct nilfs_super_block *nsbp;
 343         sector_t blocknr, newblocknr;
 344         unsigned long offset;
 345         int sb2i;  /* array index of the secondary superblock */
 346         int ret = 0;
 347
 348         /* nilfs->ns_sem must be locked by the caller. */
 349         if (nilfs->ns_sbh[1] &&
 350             nilfs->ns_sbh[1]->b_blocknr > nilfs->ns_first_data_block) {
 351                 sb2i = 1;
 352                 blocknr = nilfs->ns_sbh[1]->b_blocknr;
 353         } else if (nilfs->ns_sbh[0]->b_blocknr > nilfs->ns_first_data_block) {
 354                 sb2i = 0;
 355                 blocknr = nilfs->ns_sbh[0]->b_blocknr;
 356         } else {
 357                 sb2i = -1;
 358                 blocknr = 0;
 359         }
 360         if (sb2i >= 0 && (u64)blocknr << nilfs->ns_blocksize_bits == sb2off)
 361                 goto out;  /* super block location is unchanged */
 362
 363         /* Get new super block buffer */
 364         newblocknr = sb2off >> nilfs->ns_blocksize_bits;
 365         offset = sb2off & (nilfs->ns_blocksize - 1);
 366         nsbh = sb_getblk(sb, newblocknr);
 367         if (!nsbh) {
 368                 nilfs_warn(sb,
 369                            "unable to move secondary superblock to block %llu",
 370                            (unsigned long long)newblocknr);
 371                 ret = -EIO;
 372                 goto out;
 373         }
 374         nsbp = (void *)nsbh->b_data + offset;
 375
 376         lock_buffer(nsbh);
 377         if (sb2i >= 0) {
 378                 /*
 379                  * The position of the second superblock only changes by 4KiB,
 380                  * which is larger than the maximum superblock data size
 381                  * (= 1KiB), so there is no need to use memmove() to allow
 382                  * overlap between source and destination.
 383                  */
 384                 memcpy(nsbp, nilfs->ns_sbp[sb2i], nilfs->ns_sbsize);
 385
 386                 /*
 387                  * Zero fill after copy to avoid overwriting in case of move
 388                  * within the same block.
 389                  */
 390                 memset(nsbh->b_data, 0, offset);
 391                 memset((void *)nsbp + nilfs->ns_sbsize, 0,
 392                        nsbh->b_size - offset - nilfs->ns_sbsize);
 393         } else {
 394                 memset(nsbh->b_data, 0, nsbh->b_size);
 395         }
 396         set_buffer_uptodate(nsbh);
 397         unlock_buffer(nsbh);
 398
 399         if (sb2i >= 0) {
 400                 brelse(nilfs->ns_sbh[sb2i]);
 401                 nilfs->ns_sbh[sb2i] = nsbh;
 402                 nilfs->ns_sbp[sb2i] = nsbp;
 403         } else if (nilfs->ns_sbh[0]->b_blocknr < nilfs->ns_first_data_block) {
 404                 /* secondary super block will be restored to index 1 */
 405                 nilfs->ns_sbh[1] = nsbh;
 406                 nilfs->ns_sbp[1] = nsbp;
 407         } else {
 408                 brelse(nsbh);
 409         }
 410 out:
 411         return ret;
 412 }
 413
 414 /**
 415  * nilfs_resize_fs - resize the filesystem
 416  * @sb: super block instance
 417  * @newsize: new size of the filesystem (in bytes)
 418  */
 419 int nilfs_resize_fs(struct super_block *sb, __u64 newsize)
 420 {
 421         struct the_nilfs *nilfs = sb->s_fs_info;
 422         struct nilfs_super_block **sbp;
 423         __u64 devsize, newnsegs;
 424         loff_t sb2off;
 425         int ret;
 426
 427         ret = -ERANGE;
 428         devsize = i_size_read(sb->s_bdev->bd_inode);
 429         if (newsize > devsize)
 430                 goto out;
 431
 432         /*
 433          * Prevent underflow in second superblock position calculation.
 434          * The exact minimum size check is done in nilfs_sufile_resize().
 435          */
 436         if (newsize < 4096) {
 437                 ret = -ENOSPC;
 438                 goto out;
 439         }
 440
 441         /*
 442          * Write lock is required to protect some functions depending
 443          * on the number of segments, the number of reserved segments,
 444          * and so forth.
 445          */
 446         down_write(&nilfs->ns_segctor_sem);
 447
 448         sb2off = NILFS_SB2_OFFSET_BYTES(newsize);
 449         newnsegs = sb2off >> nilfs->ns_blocksize_bits;
 450         do_div(newnsegs, nilfs->ns_blocks_per_segment);
 451
 452         ret = nilfs_sufile_resize(nilfs->ns_sufile, newnsegs);
 453         up_write(&nilfs->ns_segctor_sem);
 454         if (ret < 0)
 455                 goto out;
 456
 457         ret = nilfs_construct_segment(sb);
 458         if (ret < 0)
 459                 goto out;
 460
 461         down_write(&nilfs->ns_sem);
 462         nilfs_move_2nd_super(sb, sb2off);
 463         ret = -EIO;
 464         sbp = nilfs_prepare_super(sb, 0);
 465         if (likely(sbp)) {
 466                 nilfs_set_log_cursor(sbp[0], nilfs);
 467                 /*
 468                  * Drop NILFS_RESIZE_FS flag for compatibility with
 469                  * mount-time resize which may be implemented in a
 470                  * future release.
 471                  */
 472                 sbp[0]->s_state = cpu_to_le16(le16_to_cpu(sbp[0]->s_state) &
 473                                               ~NILFS_RESIZE_FS);
 474                 sbp[0]->s_dev_size = cpu_to_le64(newsize);
 475                 sbp[0]->s_nsegments = cpu_to_le64(nilfs->ns_nsegments);
 476                 if (sbp[1])
 477                         memcpy(sbp[1], sbp[0], nilfs->ns_sbsize);
 478                 ret = nilfs_commit_super(sb, NILFS_SB_COMMIT_ALL);
 479         }
 480         up_write(&nilfs->ns_sem);
 481
 482         /*
 483          * Reset the range of allocatable segments last.  This order
 484          * is important in the case of expansion because the secondary
 485          * superblock must be protected from log write until migration
 486          * completes.
 487          */
 488         if (!ret)
 489                 nilfs_sufile_set_alloc_range(nilfs->ns_sufile, 0, newnsegs - 1);
 490 out:
 491         return ret;
 492 }
 493
 494 static void nilfs_put_super(struct super_block *sb)
 495 {
 496         struct the_nilfs *nilfs = sb->s_fs_info;
 497
 498         nilfs_detach_log_writer(sb);
 499
 500         if (!sb_rdonly(sb)) {
 501                 down_write(&nilfs->ns_sem);
 502                 nilfs_cleanup_super(sb);
 503                 up_write(&nilfs->ns_sem);
 504         }
 505
 506         nilfs_sysfs_delete_device_group(nilfs);
 507         iput(nilfs->ns_sufile);
 508         iput(nilfs->ns_cpfile);
 509         iput(nilfs->ns_dat);
 510
 511         destroy_nilfs(nilfs);
 512         sb->s_fs_info = NULL;
 513 }
 514
 515 static int nilfs_sync_fs(struct super_block *sb, int wait)
 516 {
 517         struct the_nilfs *nilfs = sb->s_fs_info;
 518         struct nilfs_super_block **sbp;
 519         int err = 0;
 520
 521         /* This function is called when super block should be written back */
 522         if (wait)
 523                 err = nilfs_construct_segment(sb);
 524
 525         down_write(&nilfs->ns_sem);
 526         if (nilfs_sb_dirty(nilfs)) {
 527                 sbp = nilfs_prepare_super(sb, nilfs_sb_will_flip(nilfs));
 528                 if (likely(sbp)) {
 529                         nilfs_set_log_cursor(sbp[0], nilfs);
 530                         nilfs_commit_super(sb, NILFS_SB_COMMIT);
 531                 }
 532         }
 533         up_write(&nilfs->ns_sem);
 534
 535         if (!err)
 536                 err = nilfs_flush_device(nilfs);
 537
 538         return err;
 539 }
 540
 541 int nilfs_attach_checkpoint(struct super_block *sb, __u64 cno, int curr_mnt,
 542                             struct nilfs_root **rootp)
 543 {
 544         struct the_nilfs *nilfs = sb->s_fs_info;
 545         struct nilfs_root *root;
 546         struct nilfs_checkpoint *raw_cp;
 547         struct buffer_head *bh_cp;
 548         int err = -ENOMEM;
 549
 550         root = nilfs_find_or_create_root(
 551                 nilfs, curr_mnt ? NILFS_CPTREE_CURRENT_CNO : cno);
 552         if (!root)
 553                 return err;
 554
 555         if (root->ifile)
 556                 goto reuse; /* already attached checkpoint */
 557
 558         down_read(&nilfs->ns_segctor_sem);
 559         err = nilfs_cpfile_get_checkpoint(nilfs->ns_cpfile, cno, 0, &raw_cp,
 560                                           &bh_cp);
 561         up_read(&nilfs->ns_segctor_sem);
 562         if (unlikely(err)) {
 563                 if (err == -ENOENT || err == -EINVAL) {
 564                         nilfs_err(sb,
 565                                   "Invalid checkpoint (checkpoint number=%llu)",
 566                                   (unsigned long long)cno);
 567                         err = -EINVAL;
 568                 }
 569                 goto failed;
 570         }
 571
 572         err = nilfs_ifile_read(sb, root, nilfs->ns_inode_size,
 573                                &raw_cp->cp_ifile_inode, &root->ifile);
 574         if (err)
 575                 goto failed_bh;
 576
 577         atomic64_set(&root->inodes_count,
 578                         le64_to_cpu(raw_cp->cp_inodes_count));
 579         atomic64_set(&root->blocks_count,
 580                         le64_to_cpu(raw_cp->cp_blocks_count));
 581
 582         nilfs_cpfile_put_checkpoint(nilfs->ns_cpfile, cno, bh_cp);
 583
 584  reuse:
 585         *rootp = root;
 586         return 0;
 587
 588  failed_bh:
 589         nilfs_cpfile_put_checkpoint(nilfs->ns_cpfile, cno, bh_cp);
 590  failed:
 591         nilfs_put_root(root);
 592
 593         return err;
 594 }
 595
 596 static int nilfs_freeze(struct super_block *sb)
 597 {
 598         struct the_nilfs *nilfs = sb->s_fs_info;
 599         int err;
 600
 601         if (sb_rdonly(sb))
 602                 return 0;
 603
 604         /* Mark super block clean */
 605         down_write(&nilfs->ns_sem);
 606         err = nilfs_cleanup_super(sb);
 607         up_write(&nilfs->ns_sem);
 608         return err;
 609 }
 610
 611 static int nilfs_unfreeze(struct super_block *sb)
 612 {
 613         struct the_nilfs *nilfs = sb->s_fs_info;
 614
 615         if (sb_rdonly(sb))
 616                 return 0;
 617
 618         down_write(&nilfs->ns_sem);
 619         nilfs_setup_super(sb, false);
 620         up_write(&nilfs->ns_sem);
 621         return 0;
 622 }
 623
 624 static int nilfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 625 {
 626         struct super_block *sb = dentry->d_sb;
 627         struct nilfs_root *root = NILFS_I(d_inode(dentry))->i_root;
 628         struct the_nilfs *nilfs = root->nilfs;
 629         u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
 630         unsigned long long blocks;
 631         unsigned long overhead;
 632         unsigned long nrsvblocks;
 633         sector_t nfreeblocks;
 634         u64 nmaxinodes, nfreeinodes;
 635         int err;
 636
 637         /*
 638          * Compute all of the segment blocks
 639          *
 640          * The blocks before first segment and after last segment
 641          * are excluded.
 642          */
 643         blocks = nilfs->ns_blocks_per_segment * nilfs->ns_nsegments
 644                 - nilfs->ns_first_data_block;
 645         nrsvblocks = nilfs->ns_nrsvsegs * nilfs->ns_blocks_per_segment;
 646
 647         /*
 648          * Compute the overhead
 649          *
 650          * When distributing meta data blocks outside segment structure,
 651          * We must count them as the overhead.
 652          */
 653         overhead = 0;
 654
 655         err = nilfs_count_free_blocks(nilfs, &nfreeblocks);
 656         if (unlikely(err))
 657                 return err;
 658
 659         err = nilfs_ifile_count_free_inodes(root->ifile,
 660                                             &nmaxinodes, &nfreeinodes);
 661         if (unlikely(err)) {
 662                 nilfs_warn(sb, "failed to count free inodes: err=%d", err);
 663                 if (err == -ERANGE) {
 664                         /*
 665                          * If nilfs_palloc_count_max_entries() returns
 666                          * -ERANGE error code then we simply treat
 667                          * curent inodes count as maximum possible and
 668                          * zero as free inodes value.
 669                          */
 670                         nmaxinodes = atomic64_read(&root->inodes_count);
 671                         nfreeinodes = 0;
 672                         err = 0;
 673                 } else
 674                         return err;
 675         }
 676
 677         buf->f_type = NILFS_SUPER_MAGIC;
 678         buf->f_bsize = sb->s_blocksize;
 679         buf->f_blocks = blocks - overhead;
 680         buf->f_bfree = nfreeblocks;
 681         buf->f_bavail = (buf->f_bfree >= nrsvblocks) ?
 682                 (buf->f_bfree - nrsvblocks) : 0;
 683         buf->f_files = nmaxinodes;
 684         buf->f_ffree = nfreeinodes;
 685         buf->f_namelen = NILFS_NAME_LEN;
 686         buf->f_fsid = u64_to_fsid(id);
 687
 688         return 0;
 689 }
 690
 691 static int nilfs_show_options(struct seq_file *seq, struct dentry *dentry)
 692 {
 693         struct super_block *sb = dentry->d_sb;
 694         struct the_nilfs *nilfs = sb->s_fs_info;
 695         struct nilfs_root *root = NILFS_I(d_inode(dentry))->i_root;
 696
 697         if (!nilfs_test_opt(nilfs, BARRIER))
 698                 seq_puts(seq, ",nobarrier");
 699         if (root->cno != NILFS_CPTREE_CURRENT_CNO)
 700                 seq_printf(seq, ",cp=%llu", (unsigned long long)root->cno);
 701         if (nilfs_test_opt(nilfs, ERRORS_PANIC))
 702                 seq_puts(seq, ",errors=panic");
 703         if (nilfs_test_opt(nilfs, ERRORS_CONT))
 704                 seq_puts(seq, ",errors=continue");
 705         if (nilfs_test_opt(nilfs, STRICT_ORDER))
 706                 seq_puts(seq, ",order=strict");
 707         if (nilfs_test_opt(nilfs, NORECOVERY))
 708                 seq_puts(seq, ",norecovery");
 709         if (nilfs_test_opt(nilfs, DISCARD))
 710                 seq_puts(seq, ",discard");
 711
 712         return 0;
 713 }
 714
 715 static const struct super_operations nilfs_sops = {
 716         .alloc_inode    = nilfs_alloc_inode,
 717         .free_inode     = nilfs_free_inode,
 718         .dirty_inode    = nilfs_dirty_inode,
 719         .evict_inode    = nilfs_evict_inode,
 720         .put_super      = nilfs_put_super,
 721         .sync_fs        = nilfs_sync_fs,
 722         .freeze_fs      = nilfs_freeze,
 723         .unfreeze_fs    = nilfs_unfreeze,
 724         .statfs         = nilfs_statfs,
 725         .remount_fs     = nilfs_remount,
 726         .show_options = nilfs_show_options
 727 };
 728
 729 enum {
 730         Opt_err_cont, Opt_err_panic, Opt_err_ro,
 731         Opt_barrier, Opt_nobarrier, Opt_snapshot, Opt_order, Opt_norecovery,
 732         Opt_discard, Opt_nodiscard, Opt_err,
 733 };
 734
 735 static match_table_t tokens = {
 736         {Opt_err_cont, "errors=continue"},
 737         {Opt_err_panic, "errors=panic"},
 738         {Opt_err_ro, "errors=remount-ro"},
 739         {Opt_barrier, "barrier"},
 740         {Opt_nobarrier, "nobarrier"},
 741         {Opt_snapshot, "cp=%u"},
 742         {Opt_order, "order=%s"},
 743         {Opt_norecovery, "norecovery"},
 744         {Opt_discard, "discard"},
 745         {Opt_nodiscard, "nodiscard"},
 746         {Opt_err, NULL}
 747 };
 748
 749 static int parse_options(char *options, struct super_block *sb, int is_remount)
 750 {
 751         struct the_nilfs *nilfs = sb->s_fs_info;
 752         char *p;
 753         substring_t args[MAX_OPT_ARGS];
 754
 755         if (!options)
 756                 return 1;
 757
 758         while ((p = strsep(&options, ",")) != NULL) {
 759                 int token;
 760
 761                 if (!*p)
 762                         continue;
 763
 764                 token = match_token(p, tokens, args);
 765                 switch (token) {
 766                 case Opt_barrier:
 767                         nilfs_set_opt(nilfs, BARRIER);
 768                         break;
 769                 case Opt_nobarrier:
 770                         nilfs_clear_opt(nilfs, BARRIER);
 771                         break;
 772                 case Opt_order:
 773                         if (strcmp(args[0].from, "relaxed") == 0)
 774                                 /* Ordered data semantics */
 775                                 nilfs_clear_opt(nilfs, STRICT_ORDER);
 776                         else if (strcmp(args[0].from, "strict") == 0)
 777                                 /* Strict in-order semantics */
 778                                 nilfs_set_opt(nilfs, STRICT_ORDER);
 779                         else
 780                                 return 0;
 781                         break;
 782                 case Opt_err_panic:
 783                         nilfs_write_opt(nilfs, ERROR_MODE, ERRORS_PANIC);
 784                         break;
 785                 case Opt_err_ro:
 786                         nilfs_write_opt(nilfs, ERROR_MODE, ERRORS_RO);
 787                         break;
 788                 case Opt_err_cont:
 789                         nilfs_write_opt(nilfs, ERROR_MODE, ERRORS_CONT);
 790                         break;
 791                 case Opt_snapshot:
 792                         if (is_remount) {
 793                                 nilfs_err(sb,
 794                                           "\"%s\" option is invalid for remount",
 795                                           p);
 796                                 return 0;
 797                         }
 798                         break;
 799                 case Opt_norecovery:
 800                         nilfs_set_opt(nilfs, NORECOVERY);
 801                         break;
 802                 case Opt_discard:
 803                         nilfs_set_opt(nilfs, DISCARD);
 804                         break;
 805                 case Opt_nodiscard:
 806                         nilfs_clear_opt(nilfs, DISCARD);
 807                         break;
 808                 default:
 809                         nilfs_err(sb, "unrecognized mount option \"%s\"", p);
 810                         return 0;
 811                 }
 812         }
 813         return 1;
 814 }
 815
 816 static inline void
 817 nilfs_set_default_options(struct super_block *sb,
 818                           struct nilfs_super_block *sbp)
 819 {
 820         struct the_nilfs *nilfs = sb->s_fs_info;
 821
 822         nilfs->ns_mount_opt =
 823                 NILFS_MOUNT_ERRORS_RO | NILFS_MOUNT_BARRIER;
 824 }
 825
 826 static int nilfs_setup_super(struct super_block *sb, int is_mount)
 827 {
 828         struct the_nilfs *nilfs = sb->s_fs_info;
 829         struct nilfs_super_block **sbp;
 830         int max_mnt_count;
 831         int mnt_count;
 832
 833         /* nilfs->ns_sem must be locked by the caller. */
 834         sbp = nilfs_prepare_super(sb, 0);
 835         if (!sbp)
 836                 return -EIO;
 837
 838         if (!is_mount)
 839                 goto skip_mount_setup;
 840
 841         max_mnt_count = le16_to_cpu(sbp[0]->s_max_mnt_count);
 842         mnt_count = le16_to_cpu(sbp[0]->s_mnt_count);
 843
 844         if (nilfs->ns_mount_state & NILFS_ERROR_FS) {
 845                 nilfs_warn(sb, "mounting fs with errors");
 846 #if 0
 847         } else if (max_mnt_count >= 0 && mnt_count >= max_mnt_count) {
 848                 nilfs_warn(sb, "maximal mount count reached");
 849 #endif
 850         }
 851         if (!max_mnt_count)
 852                 sbp[0]->s_max_mnt_count = cpu_to_le16(NILFS_DFL_MAX_MNT_COUNT);
 853
 854         sbp[0]->s_mnt_count = cpu_to_le16(mnt_count + 1);
 855         sbp[0]->s_mtime = cpu_to_le64(ktime_get_real_seconds());
 856
 857 skip_mount_setup:
 858         sbp[0]->s_state =
 859                 cpu_to_le16(le16_to_cpu(sbp[0]->s_state) & ~NILFS_VALID_FS);
 860         /* synchronize sbp[1] with sbp[0] */
 861         if (sbp[1])
 862                 memcpy(sbp[1], sbp[0], nilfs->ns_sbsize);
 863         return nilfs_commit_super(sb, NILFS_SB_COMMIT_ALL);
 864 }
 865
 866 struct nilfs_super_block *nilfs_read_super_block(struct super_block *sb,
 867                                                  u64 pos, int blocksize,
 868                                                  struct buffer_head **pbh)
 869 {
 870         unsigned long long sb_index = pos;
 871         unsigned long offset;
 872
 873         offset = do_div(sb_index, blocksize);
 874         *pbh = sb_bread(sb, sb_index);
 875         if (!*pbh)
 876                 return NULL;
 877         return (struct nilfs_super_block *)((char *)(*pbh)->b_data + offset);
 878 }
 879
 880 int nilfs_store_magic_and_option(struct super_block *sb,
 881                                  struct nilfs_super_block *sbp,
 882                                  char *data)
 883 {
 884         struct the_nilfs *nilfs = sb->s_fs_info;
 885
 886         sb->s_magic = le16_to_cpu(sbp->s_magic);
 887
 888         /* FS independent flags */
 889 #ifdef NILFS_ATIME_DISABLE
 890         sb->s_flags |= SB_NOATIME;
 891 #endif
 892
 893         nilfs_set_default_options(sb, sbp);
 894
 895         nilfs->ns_resuid = le16_to_cpu(sbp->s_def_resuid);
 896         nilfs->ns_resgid = le16_to_cpu(sbp->s_def_resgid);
 897         nilfs->ns_interval = le32_to_cpu(sbp->s_c_interval);
 898         nilfs->ns_watermark = le32_to_cpu(sbp->s_c_block_max);
 899
 900         return !parse_options(data, sb, 0) ? -EINVAL : 0;
 901 }
 902
 903 int nilfs_check_feature_compatibility(struct super_block *sb,
 904                                       struct nilfs_super_block *sbp)
 905 {
 906         __u64 features;
 907
 908         features = le64_to_cpu(sbp->s_feature_incompat) &
 909                 ~NILFS_FEATURE_INCOMPAT_SUPP;
 910         if (features) {
 911                 nilfs_err(sb,
 912                           "couldn't mount because of unsupported optional features (%llx)",
 913                           (unsigned long long)features);
 914                 return -EINVAL;
 915         }
 916         features = le64_to_cpu(sbp->s_feature_compat_ro) &
 917                 ~NILFS_FEATURE_COMPAT_RO_SUPP;
 918         if (!sb_rdonly(sb) && features) {
 919                 nilfs_err(sb,
 920                           "couldn't mount RDWR because of unsupported optional features (%llx)",
 921                           (unsigned long long)features);
 922                 return -EINVAL;
 923         }
 924         return 0;
 925 }
 926
 927 static int nilfs_get_root_dentry(struct super_block *sb,
 928                                  struct nilfs_root *root,
 929                                  struct dentry **root_dentry)
 930 {
 931         struct inode *inode;
 932         struct dentry *dentry;
 933         int ret = 0;
 934
 935         inode = nilfs_iget(sb, root, NILFS_ROOT_INO);
 936         if (IS_ERR(inode)) {
 937                 ret = PTR_ERR(inode);
 938                 nilfs_err(sb, "error %d getting root inode", ret);
 939                 goto out;
 940         }
 941         if (!S_ISDIR(inode->i_mode) || !inode->i_blocks || !inode->i_size) {
 942                 iput(inode);
 943                 nilfs_err(sb, "corrupt root inode");
 944                 ret = -EINVAL;
 945                 goto out;
 946         }
 947
 948         if (root->cno == NILFS_CPTREE_CURRENT_CNO) {
 949                 dentry = d_find_alias(inode);
 950                 if (!dentry) {
 951                         dentry = d_make_root(inode);
 952                         if (!dentry) {
 953                                 ret = -ENOMEM;
 954                                 goto failed_dentry;
 955                         }
 956                 } else {
 957                         iput(inode);
 958                 }
 959         } else {
 960                 dentry = d_obtain_root(inode);
 961                 if (IS_ERR(dentry)) {
 962                         ret = PTR_ERR(dentry);
 963                         goto failed_dentry;
 964                 }
 965         }
 966         *root_dentry = dentry;
 967  out:
 968         return ret;
 969
 970  failed_dentry:
 971         nilfs_err(sb, "error %d getting root dentry", ret);
 972         goto out;
 973 }
 974
 975 static int nilfs_attach_snapshot(struct super_block *s, __u64 cno,
 976                                  struct dentry **root_dentry)
 977 {
 978         struct the_nilfs *nilfs = s->s_fs_info;
 979         struct nilfs_root *root;
 980         int ret;
 981
 982         mutex_lock(&nilfs->ns_snapshot_mount_mutex);
 983
 984         down_read(&nilfs->ns_segctor_sem);
 985         ret = nilfs_cpfile_is_snapshot(nilfs->ns_cpfile, cno);
 986         up_read(&nilfs->ns_segctor_sem);
 987         if (ret < 0) {
 988                 ret = (ret == -ENOENT) ? -EINVAL : ret;
 989                 goto out;
 990         } else if (!ret) {
 991                 nilfs_err(s,
 992                           "The specified checkpoint is not a snapshot (checkpoint number=%llu)",
 993                           (unsigned long long)cno);
 994                 ret = -EINVAL;
 995                 goto out;
 996         }
 997
 998         ret = nilfs_attach_checkpoint(s, cno, false, &root);
 999         if (ret) {
1000                 nilfs_err(s,
1001                           "error %d while loading snapshot (checkpoint number=%llu)",
1002                           ret, (unsigned long long)cno);
1003                 goto out;
1004         }
1005         ret = nilfs_get_root_dentry(s, root, root_dentry);
1006         nilfs_put_root(root);
1007  out:
1008         mutex_unlock(&nilfs->ns_snapshot_mount_mutex);
1009         return ret;
1010 }
1011
1012 /**
1013  * nilfs_tree_is_busy() - try to shrink dentries of a checkpoint
1014  * @root_dentry: root dentry of the tree to be shrunk
1015  *
1016  * This function returns true if the tree was in-use.
1017  */
1018 static bool nilfs_tree_is_busy(struct dentry *root_dentry)
1019 {
1020         shrink_dcache_parent(root_dentry);
1021         return d_count(root_dentry) > 1;
1022 }
1023
1024 int nilfs_checkpoint_is_mounted(struct super_block *sb, __u64 cno)
1025 {
1026         struct the_nilfs *nilfs = sb->s_fs_info;
1027         struct nilfs_root *root;
1028         struct inode *inode;
1029         struct dentry *dentry;
1030         int ret;
1031
1032         if (cno > nilfs->ns_cno)
1033                 return false;
1034
1035         if (cno >= nilfs_last_cno(nilfs))
1036                 return true;    /* protect recent checkpoints */
1037
1038         ret = false;
1039         root = nilfs_lookup_root(nilfs, cno);
1040         if (root) {
1041                 inode = nilfs_ilookup(sb, root, NILFS_ROOT_INO);
1042                 if (inode) {
1043                         dentry = d_find_alias(inode);
1044                         if (dentry) {
1045                                 ret = nilfs_tree_is_busy(dentry);
1046                                 dput(dentry);
1047                         }
1048                         iput(inode);
1049                 }
1050                 nilfs_put_root(root);
1051         }
1052         return ret;
1053 }
1054
1055 /**
1056  * nilfs_fill_super() - initialize a super block instance
1057  * @sb: super_block
1058  * @data: mount options
1059  * @silent: silent mode flag
1060  *
1061  * This function is called exclusively by nilfs->ns_mount_mutex.
1062  * So, the recovery process is protected from other simultaneous mounts.
1063  */
1064 static int
1065 nilfs_fill_super(struct super_block *sb, void *data, int silent)
1066 {
1067         struct the_nilfs *nilfs;
1068         struct nilfs_root *fsroot;
1069         __u64 cno;
1070         int err;
1071
1072         nilfs = alloc_nilfs(sb);
1073         if (!nilfs)
1074                 return -ENOMEM;
1075
1076         sb->s_fs_info = nilfs;
1077
1078         err = init_nilfs(nilfs, sb, (char *)data);
1079         if (err)
1080                 goto failed_nilfs;
1081
1082         sb->s_op = &nilfs_sops;
1083         sb->s_export_op = &nilfs_export_ops;
1084         sb->s_root = NULL;
1085         sb->s_time_gran = 1;
1086         sb->s_max_links = NILFS_LINK_MAX;
1087
1088         sb->s_bdi = bdi_get(sb->s_bdev->bd_bdi);
1089
1090         err = load_nilfs(nilfs, sb);
1091         if (err)
1092                 goto failed_nilfs;
1093
1094         cno = nilfs_last_cno(nilfs);
1095         err = nilfs_attach_checkpoint(sb, cno, true, &fsroot);
1096         if (err) {
1097                 nilfs_err(sb,
1098                           "error %d while loading last checkpoint (checkpoint number=%llu)",
1099                           err, (unsigned long long)cno);
1100                 goto failed_unload;
1101         }
1102
1103         if (!sb_rdonly(sb)) {
1104                 err = nilfs_attach_log_writer(sb, fsroot);
1105                 if (err)
1106                         goto failed_checkpoint;
1107         }
1108
1109         err = nilfs_get_root_dentry(sb, fsroot, &sb->s_root);
1110         if (err)
1111                 goto failed_segctor;
1112
1113         nilfs_put_root(fsroot);
1114
1115         if (!sb_rdonly(sb)) {
1116                 down_write(&nilfs->ns_sem);
1117                 nilfs_setup_super(sb, true);
1118                 up_write(&nilfs->ns_sem);
1119         }
1120
1121         return 0;
1122
1123  failed_segctor:
1124         nilfs_detach_log_writer(sb);
1125
1126  failed_checkpoint:
1127         nilfs_put_root(fsroot);
1128
1129  failed_unload:
1130         nilfs_sysfs_delete_device_group(nilfs);
1131         iput(nilfs->ns_sufile);
1132         iput(nilfs->ns_cpfile);
1133         iput(nilfs->ns_dat);
1134
1135  failed_nilfs:
1136         destroy_nilfs(nilfs);
1137         return err;
1138 }
1139
1140 static int nilfs_remount(struct super_block *sb, int *flags, char *data)
1141 {
1142         struct the_nilfs *nilfs = sb->s_fs_info;
1143         unsigned long old_sb_flags;
1144         unsigned long old_mount_opt;
1145         int err;
1146
1147         sync_filesystem(sb);
1148         old_sb_flags = sb->s_flags;
1149         old_mount_opt = nilfs->ns_mount_opt;
1150
1151         if (!parse_options(data, sb, 1)) {
1152                 err = -EINVAL;
1153                 goto restore_opts;
1154         }
1155         sb->s_flags = (sb->s_flags & ~SB_POSIXACL);
1156
1157         err = -EINVAL;
1158
1159         if (!nilfs_valid_fs(nilfs)) {
1160                 nilfs_warn(sb,
1161                            "couldn't remount because the filesystem is in an incomplete recovery state");
1162                 goto restore_opts;
1163         }
1164
1165         if ((bool)(*flags & SB_RDONLY) == sb_rdonly(sb))
1166                 goto out;
1167         if (*flags & SB_RDONLY) {
1168                 sb->s_flags |= SB_RDONLY;
1169
1170                 /*
1171                  * Remounting a valid RW partition RDONLY, so set
1172                  * the RDONLY flag and then mark the partition as valid again.
1173                  */
1174                 down_write(&nilfs->ns_sem);
1175                 nilfs_cleanup_super(sb);
1176                 up_write(&nilfs->ns_sem);
1177         } else {
1178                 __u64 features;
1179                 struct nilfs_root *root;
1180
1181                 /*
1182                  * Mounting a RDONLY partition read-write, so reread and
1183                  * store the current valid flag.  (It may have been changed
1184                  * by fsck since we originally mounted the partition.)
1185                  */
1186                 down_read(&nilfs->ns_sem);
1187                 features = le64_to_cpu(nilfs->ns_sbp[0]->s_feature_compat_ro) &
1188                         ~NILFS_FEATURE_COMPAT_RO_SUPP;
1189                 up_read(&nilfs->ns_sem);
1190                 if (features) {
1191                         nilfs_warn(sb,
1192                                    "couldn't remount RDWR because of unsupported optional features (%llx)",
1193                                    (unsigned long long)features);
1194                         err = -EROFS;
1195                         goto restore_opts;
1196                 }
1197
1198                 sb->s_flags &= ~SB_RDONLY;
1199
1200                 root = NILFS_I(d_inode(sb->s_root))->i_root;
1201                 err = nilfs_attach_log_writer(sb, root);
1202                 if (err)
1203                         goto restore_opts;
1204
1205                 down_write(&nilfs->ns_sem);
1206                 nilfs_setup_super(sb, true);
1207                 up_write(&nilfs->ns_sem);
1208         }
1209  out:
1210         return 0;
1211
1212  restore_opts:
1213         sb->s_flags = old_sb_flags;
1214         nilfs->ns_mount_opt = old_mount_opt;
1215         return err;
1216 }
1217
1218 struct nilfs_super_data {
1219         struct block_device *bdev;
1220         __u64 cno;
1221         int flags;
1222 };
1223
1224 static int nilfs_parse_snapshot_option(const char *option,
1225                                        const substring_t *arg,
1226                                        struct nilfs_super_data *sd)
1227 {
1228         unsigned long long val;
1229         const char *msg = NULL;
1230         int err;
1231
1232         if (!(sd->flags & SB_RDONLY)) {
1233                 msg = "read-only option is not specified";
1234                 goto parse_error;
1235         }
1236
1237         err = kstrtoull(arg->from, 0, &val);
1238         if (err) {
1239                 if (err == -ERANGE)
1240                         msg = "too large checkpoint number";
1241                 else
1242                         msg = "malformed argument";
1243                 goto parse_error;
1244         } else if (val == 0) {
1245                 msg = "invalid checkpoint number 0";
1246                 goto parse_error;
1247         }
1248         sd->cno = val;
1249         return 0;
1250
1251 parse_error:
1252         nilfs_err(NULL, "invalid option \"%s\": %s", option, msg);
1253         return 1;
1254 }
1255
1256 /**
1257  * nilfs_identify - pre-read mount options needed to identify mount instance
1258  * @data: mount options
1259  * @sd: nilfs_super_data
1260  */
1261 static int nilfs_identify(char *data, struct nilfs_super_data *sd)
1262 {
1263         char *p, *options = data;
1264         substring_t args[MAX_OPT_ARGS];
1265         int token;
1266         int ret = 0;
1267
1268         do {
1269                 p = strsep(&options, ",");
1270                 if (p != NULL && *p) {
1271                         token = match_token(p, tokens, args);
1272                         if (token == Opt_snapshot)
1273                                 ret = nilfs_parse_snapshot_option(p, &args[0],
1274                                                                   sd);
1275                 }
1276                 if (!options)
1277                         break;
1278                 BUG_ON(options == data);
1279                 *(options - 1) = ',';
1280         } while (!ret);
1281         return ret;
1282 }
1283
1284 static int nilfs_set_bdev_super(struct super_block *s, void *data)
1285 {
1286         s->s_bdev = data;
1287         s->s_dev = s->s_bdev->bd_dev;
1288         return 0;
1289 }
1290
1291 static int nilfs_test_bdev_super(struct super_block *s, void *data)
1292 {
1293         return (void *)s->s_bdev == data;
1294 }
1295
1296 static struct dentry *
1297 nilfs_mount(struct file_system_type *fs_type, int flags,
1298              const char *dev_name, void *data)
1299 {
1300         struct nilfs_super_data sd;
1301         struct super_block *s;
1302         fmode_t mode = FMODE_READ | FMODE_EXCL;
1303         struct dentry *root_dentry;
1304         int err, s_new = false;
1305
1306         if (!(flags & SB_RDONLY))
1307                 mode |= FMODE_WRITE;
1308
1309         sd.bdev = blkdev_get_by_path(dev_name, mode, fs_type);
1310         if (IS_ERR(sd.bdev))
1311                 return ERR_CAST(sd.bdev);
1312
1313         sd.cno = 0;
1314         sd.flags = flags;
1315         if (nilfs_identify((char *)data, &sd)) {
1316                 err = -EINVAL;
1317                 goto failed;
1318         }
1319
1320         /*
1321          * once the super is inserted into the list by sget, s_umount
1322          * will protect the lockfs code from trying to start a snapshot
1323          * while we are mounting
1324          */
1325         mutex_lock(&sd.bdev->bd_fsfreeze_mutex);
1326         if (sd.bdev->bd_fsfreeze_count > 0) {
1327                 mutex_unlock(&sd.bdev->bd_fsfreeze_mutex);
1328                 err = -EBUSY;
1329                 goto failed;
1330         }
1331         s = sget(fs_type, nilfs_test_bdev_super, nilfs_set_bdev_super, flags,
1332                  sd.bdev);
1333         mutex_unlock(&sd.bdev->bd_fsfreeze_mutex);
1334         if (IS_ERR(s)) {
1335                 err = PTR_ERR(s);
1336                 goto failed;
1337         }
1338
1339         if (!s->s_root) {
1340                 s_new = true;
1341
1342                 /* New superblock instance created */
1343                 s->s_mode = mode;
1344                 snprintf(s->s_id, sizeof(s->s_id), "%pg", sd.bdev);
1345                 sb_set_blocksize(s, block_size(sd.bdev));
1346
1347                 err = nilfs_fill_super(s, data, flags & SB_SILENT ? 1 : 0);
1348                 if (err)
1349                         goto failed_super;
1350
1351                 s->s_flags |= SB_ACTIVE;
1352         } else if (!sd.cno) {
1353                 if (nilfs_tree_is_busy(s->s_root)) {
1354                         if ((flags ^ s->s_flags) & SB_RDONLY) {
1355                                 nilfs_err(s,
1356                                           "the device already has a %s mount.",
1357                                           sb_rdonly(s) ? "read-only" : "read/write");
1358                                 err = -EBUSY;
1359                                 goto failed_super;
1360                         }
1361                 } else {
1362                         /*
1363                          * Try remount to setup mount states if the current
1364                          * tree is not mounted and only snapshots use this sb.
1365                          */
1366                         err = nilfs_remount(s, &flags, data);
1367                         if (err)
1368                                 goto failed_super;
1369                 }
1370         }
1371
1372         if (sd.cno) {
1373                 err = nilfs_attach_snapshot(s, sd.cno, &root_dentry);
1374                 if (err)
1375                         goto failed_super;
1376         } else {
1377                 root_dentry = dget(s->s_root);
1378         }
1379
1380         if (!s_new)
1381                 blkdev_put(sd.bdev, mode);
1382
1383         return root_dentry;
1384
1385  failed_super:
1386         deactivate_locked_super(s);
1387
1388  failed:
1389         if (!s_new)
1390                 blkdev_put(sd.bdev, mode);
1391         return ERR_PTR(err);
1392 }
1393
1394 struct file_system_type nilfs_fs_type = {
1395         .owner    = THIS_MODULE,
1396         .name     = "nilfs2",
1397         .mount    = nilfs_mount,
1398         .kill_sb  = kill_block_super,
1399         .fs_flags = FS_REQUIRES_DEV,
1400 };
1401 MODULE_ALIAS_FS("nilfs2");
1402
1403 static void nilfs_inode_init_once(void *obj)
1404 {
1405         struct nilfs_inode_info *ii = obj;
1406
1407         INIT_LIST_HEAD(&ii->i_dirty);
1408 #ifdef CONFIG_NILFS_XATTR
1409         init_rwsem(&ii->xattr_sem);
1410 #endif
1411         inode_init_once(&ii->vfs_inode);
1412 }
1413
1414 static void nilfs_segbuf_init_once(void *obj)
1415 {
1416         memset(obj, 0, sizeof(struct nilfs_segment_buffer));
1417 }
1418
1419 static void nilfs_destroy_cachep(void)
1420 {
1421         /*
1422          * Make sure all delayed rcu free inodes are flushed before we
1423          * destroy cache.
1424          */
1425         rcu_barrier();
1426
1427         kmem_cache_destroy(nilfs_inode_cachep);
1428         kmem_cache_destroy(nilfs_transaction_cachep);
1429         kmem_cache_destroy(nilfs_segbuf_cachep);
1430         kmem_cache_destroy(nilfs_btree_path_cache);
1431 }
1432
1433 static int __init nilfs_init_cachep(void)
1434 {
1435         nilfs_inode_cachep = kmem_cache_create("nilfs2_inode_cache",
1436                         sizeof(struct nilfs_inode_info), 0,
1437                         SLAB_RECLAIM_ACCOUNT|SLAB_ACCOUNT,
1438                         nilfs_inode_init_once);
1439         if (!nilfs_inode_cachep)
1440                 goto fail;
1441
1442         nilfs_transaction_cachep = kmem_cache_create("nilfs2_transaction_cache",
1443                         sizeof(struct nilfs_transaction_info), 0,
1444                         SLAB_RECLAIM_ACCOUNT, NULL);
1445         if (!nilfs_transaction_cachep)
1446                 goto fail;
1447
1448         nilfs_segbuf_cachep = kmem_cache_create("nilfs2_segbuf_cache",
1449                         sizeof(struct nilfs_segment_buffer), 0,
1450                         SLAB_RECLAIM_ACCOUNT, nilfs_segbuf_init_once);
1451         if (!nilfs_segbuf_cachep)
1452                 goto fail;
1453
1454         nilfs_btree_path_cache = kmem_cache_create("nilfs2_btree_path_cache",
1455                         sizeof(struct nilfs_btree_path) * NILFS_BTREE_LEVEL_MAX,
1456                         0, 0, NULL);
1457         if (!nilfs_btree_path_cache)
1458                 goto fail;
1459
1460         return 0;
1461
1462 fail:
1463         nilfs_destroy_cachep();
1464         return -ENOMEM;
1465 }
1466
1467 static int __init init_nilfs_fs(void)
1468 {
1469         int err;
1470
1471         err = nilfs_init_cachep();
1472         if (err)
1473                 goto fail;
1474
1475         err = nilfs_sysfs_init();
1476         if (err)
1477                 goto free_cachep;
1478
1479         err = register_filesystem(&nilfs_fs_type);
1480         if (err)
1481                 goto deinit_sysfs_entry;
1482
1483         printk(KERN_INFO "NILFS version 2 loaded\n");
1484         return 0;
1485
1486 deinit_sysfs_entry:
1487         nilfs_sysfs_exit();
1488 free_cachep:
1489         nilfs_destroy_cachep();
1490 fail:
1491         return err;
1492 }
1493
1494 static void __exit exit_nilfs_fs(void)
1495 {
1496         nilfs_destroy_cachep();
1497         nilfs_sysfs_exit();
1498         unregister_filesystem(&nilfs_fs_type);
1499 }
1500
1501 module_init(init_nilfs_fs)
1502 module_exit(exit_nilfs_fs)