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 *level, const char *fmt,
  66                  ...)
  67 {
  68         struct va_format vaf;
  69         va_list args;
  70
  71         va_start(args, fmt);
  72         vaf.fmt = fmt;
  73         vaf.va = &args;
  74         if (sb)
  75                 printk("%sNILFS (%s): %pV\n", level, sb->s_id, &vaf);
  76         else
  77                 printk("%sNILFS: %pV\n", level, &vaf);
  78         va_end(args);
  79 }
  80
  81 static void nilfs_set_error(struct super_block *sb)
  82 {
  83         struct the_nilfs *nilfs = sb->s_fs_info;
  84         struct nilfs_super_block **sbp;
  85
  86         down_write(&nilfs->ns_sem);
  87         if (!(nilfs->ns_mount_state & NILFS_ERROR_FS)) {
  88                 nilfs->ns_mount_state |= NILFS_ERROR_FS;
  89                 sbp = nilfs_prepare_super(sb, 0);
  90                 if (likely(sbp)) {
  91                         sbp[0]->s_state |= cpu_to_le16(NILFS_ERROR_FS);
  92                         if (sbp[1])
  93                                 sbp[1]->s_state |= cpu_to_le16(NILFS_ERROR_FS);
  94                         nilfs_commit_super(sb, NILFS_SB_COMMIT_ALL);
  95                 }
  96         }
  97         up_write(&nilfs->ns_sem);
  98 }
  99
 100 /**
 101  * __nilfs_error() - report failure condition on a filesystem
 102  *
 103  * __nilfs_error() sets an ERROR_FS flag on the superblock as well as
 104  * reporting an error message.  This function should be called when
 105  * NILFS detects incoherences or defects of meta data on disk.
 106  *
 107  * This implements the body of nilfs_error() macro.  Normally,
 108  * nilfs_error() should be used.  As for sustainable errors such as a
 109  * single-shot I/O error, nilfs_msg() should be used instead.
 110  *
 111  * Callers should not add a trailing newline since this will do it.
 112  */
 113 void __nilfs_error(struct super_block *sb, const char *function,
 114                    const char *fmt, ...)
 115 {
 116         struct the_nilfs *nilfs = sb->s_fs_info;
 117         struct va_format vaf;
 118         va_list args;
 119
 120         va_start(args, fmt);
 121
 122         vaf.fmt = fmt;
 123         vaf.va = &args;
 124
 125         printk(KERN_CRIT "NILFS error (device %s): %s: %pV\n",
 126                sb->s_id, function, &vaf);
 127
 128         va_end(args);
 129
 130         if (!sb_rdonly(sb)) {
 131                 nilfs_set_error(sb);
 132
 133                 if (nilfs_test_opt(nilfs, ERRORS_RO)) {
 134                         printk(KERN_CRIT "Remounting filesystem read-only\n");
 135                         sb->s_flags |= SB_RDONLY;
 136                 }
 137         }
 138
 139         if (nilfs_test_opt(nilfs, ERRORS_PANIC))
 140                 panic("NILFS (device %s): panic forced after error\n",
 141                       sb->s_id);
 142 }
 143
 144 struct inode *nilfs_alloc_inode(struct super_block *sb)
 145 {
 146         struct nilfs_inode_info *ii;
 147
 148         ii = kmem_cache_alloc(nilfs_inode_cachep, GFP_NOFS);
 149         if (!ii)
 150                 return NULL;
 151         ii->i_bh = NULL;
 152         ii->i_state = 0;
 153         ii->i_cno = 0;
 154         ii->i_assoc_inode = NULL;
 155         ii->i_bmap = &ii->i_bmap_data;
 156         return &ii->vfs_inode;
 157 }
 158
 159 static void nilfs_free_inode(struct inode *inode)
 160 {
 161         if (nilfs_is_metadata_file_inode(inode))
 162                 nilfs_mdt_destroy(inode);
 163
 164         kmem_cache_free(nilfs_inode_cachep, NILFS_I(inode));
 165 }
 166
 167 static int nilfs_sync_super(struct super_block *sb, int flag)
 168 {
 169         struct the_nilfs *nilfs = sb->s_fs_info;
 170         int err;
 171
 172  retry:
 173         set_buffer_dirty(nilfs->ns_sbh[0]);
 174         if (nilfs_test_opt(nilfs, BARRIER)) {
 175                 err = __sync_dirty_buffer(nilfs->ns_sbh[0],
 176                                           REQ_SYNC | REQ_PREFLUSH | REQ_FUA);
 177         } else {
 178                 err = sync_dirty_buffer(nilfs->ns_sbh[0]);
 179         }
 180
 181         if (unlikely(err)) {
 182                 nilfs_msg(sb, KERN_ERR, "unable to write superblock: err=%d",
 183                           err);
 184                 if (err == -EIO && nilfs->ns_sbh[1]) {
 185                         /*
 186                          * sbp[0] points to newer log than sbp[1],
 187                          * so copy sbp[0] to sbp[1] to take over sbp[0].
 188                          */
 189                         memcpy(nilfs->ns_sbp[1], nilfs->ns_sbp[0],
 190                                nilfs->ns_sbsize);
 191                         nilfs_fall_back_super_block(nilfs);
 192                         goto retry;
 193                 }
 194         } else {
 195                 struct nilfs_super_block *sbp = nilfs->ns_sbp[0];
 196
 197                 nilfs->ns_sbwcount++;
 198
 199                 /*
 200                  * The latest segment becomes trailable from the position
 201                  * written in superblock.
 202                  */
 203                 clear_nilfs_discontinued(nilfs);
 204
 205                 /* update GC protection for recent segments */
 206                 if (nilfs->ns_sbh[1]) {
 207                         if (flag == NILFS_SB_COMMIT_ALL) {
 208                                 set_buffer_dirty(nilfs->ns_sbh[1]);
 209                                 if (sync_dirty_buffer(nilfs->ns_sbh[1]) < 0)
 210                                         goto out;
 211                         }
 212                         if (le64_to_cpu(nilfs->ns_sbp[1]->s_last_cno) <
 213                             le64_to_cpu(nilfs->ns_sbp[0]->s_last_cno))
 214                                 sbp = nilfs->ns_sbp[1];
 215                 }
 216
 217                 spin_lock(&nilfs->ns_last_segment_lock);
 218                 nilfs->ns_prot_seq = le64_to_cpu(sbp->s_last_seq);
 219                 spin_unlock(&nilfs->ns_last_segment_lock);
 220         }
 221  out:
 222         return err;
 223 }
 224
 225 void nilfs_set_log_cursor(struct nilfs_super_block *sbp,
 226                           struct the_nilfs *nilfs)
 227 {
 228         sector_t nfreeblocks;
 229
 230         /* nilfs->ns_sem must be locked by the caller. */
 231         nilfs_count_free_blocks(nilfs, &nfreeblocks);
 232         sbp->s_free_blocks_count = cpu_to_le64(nfreeblocks);
 233
 234         spin_lock(&nilfs->ns_last_segment_lock);
 235         sbp->s_last_seq = cpu_to_le64(nilfs->ns_last_seq);
 236         sbp->s_last_pseg = cpu_to_le64(nilfs->ns_last_pseg);
 237         sbp->s_last_cno = cpu_to_le64(nilfs->ns_last_cno);
 238         spin_unlock(&nilfs->ns_last_segment_lock);
 239 }
 240
 241 struct nilfs_super_block **nilfs_prepare_super(struct super_block *sb,
 242                                                int flip)
 243 {
 244         struct the_nilfs *nilfs = sb->s_fs_info;
 245         struct nilfs_super_block **sbp = nilfs->ns_sbp;
 246
 247         /* nilfs->ns_sem must be locked by the caller. */
 248         if (sbp[0]->s_magic != cpu_to_le16(NILFS_SUPER_MAGIC)) {
 249                 if (sbp[1] &&
 250                     sbp[1]->s_magic == cpu_to_le16(NILFS_SUPER_MAGIC)) {
 251                         memcpy(sbp[0], sbp[1], nilfs->ns_sbsize);
 252                 } else {
 253                         nilfs_msg(sb, KERN_CRIT, "superblock broke");
 254                         return NULL;
 255                 }
 256         } else if (sbp[1] &&
 257                    sbp[1]->s_magic != cpu_to_le16(NILFS_SUPER_MAGIC)) {
 258                 memcpy(sbp[1], sbp[0], nilfs->ns_sbsize);
 259         }
 260
 261         if (flip && sbp[1])
 262                 nilfs_swap_super_block(nilfs);
 263
 264         return sbp;
 265 }
 266
 267 int nilfs_commit_super(struct super_block *sb, int flag)
 268 {
 269         struct the_nilfs *nilfs = sb->s_fs_info;
 270         struct nilfs_super_block **sbp = nilfs->ns_sbp;
 271         time64_t t;
 272
 273         /* nilfs->ns_sem must be locked by the caller. */
 274         t = ktime_get_real_seconds();
 275         nilfs->ns_sbwtime = t;
 276         sbp[0]->s_wtime = cpu_to_le64(t);
 277         sbp[0]->s_sum = 0;
 278         sbp[0]->s_sum = cpu_to_le32(crc32_le(nilfs->ns_crc_seed,
 279                                              (unsigned char *)sbp[0],
 280                                              nilfs->ns_sbsize));
 281         if (flag == NILFS_SB_COMMIT_ALL && sbp[1]) {
 282                 sbp[1]->s_wtime = sbp[0]->s_wtime;
 283                 sbp[1]->s_sum = 0;
 284                 sbp[1]->s_sum = cpu_to_le32(crc32_le(nilfs->ns_crc_seed,
 285                                             (unsigned char *)sbp[1],
 286                                             nilfs->ns_sbsize));
 287         }
 288         clear_nilfs_sb_dirty(nilfs);
 289         nilfs->ns_flushed_device = 1;
 290         /* make sure store to ns_flushed_device cannot be reordered */
 291         smp_wmb();
 292         return nilfs_sync_super(sb, flag);
 293 }
 294
 295 /**
 296  * nilfs_cleanup_super() - write filesystem state for cleanup
 297  * @sb: super block instance to be unmounted or degraded to read-only
 298  *
 299  * This function restores state flags in the on-disk super block.
 300  * This will set "clean" flag (i.e. NILFS_VALID_FS) unless the
 301  * filesystem was not clean previously.
 302  */
 303 int nilfs_cleanup_super(struct super_block *sb)
 304 {
 305         struct the_nilfs *nilfs = sb->s_fs_info;
 306         struct nilfs_super_block **sbp;
 307         int flag = NILFS_SB_COMMIT;
 308         int ret = -EIO;
 309
 310         sbp = nilfs_prepare_super(sb, 0);
 311         if (sbp) {
 312                 sbp[0]->s_state = cpu_to_le16(nilfs->ns_mount_state);
 313                 nilfs_set_log_cursor(sbp[0], nilfs);
 314                 if (sbp[1] && sbp[0]->s_last_cno == sbp[1]->s_last_cno) {
 315                         /*
 316                          * make the "clean" flag also to the opposite
 317                          * super block if both super blocks point to
 318                          * the same checkpoint.
 319                          */
 320                         sbp[1]->s_state = sbp[0]->s_state;
 321                         flag = NILFS_SB_COMMIT_ALL;
 322                 }
 323                 ret = nilfs_commit_super(sb, flag);
 324         }
 325         return ret;
 326 }
 327
 328 /**
 329  * nilfs_move_2nd_super - relocate secondary super block
 330  * @sb: super block instance
 331  * @sb2off: new offset of the secondary super block (in bytes)
 332  */
 333 static int nilfs_move_2nd_super(struct super_block *sb, loff_t sb2off)
 334 {
 335         struct the_nilfs *nilfs = sb->s_fs_info;
 336         struct buffer_head *nsbh;
 337         struct nilfs_super_block *nsbp;
 338         sector_t blocknr, newblocknr;
 339         unsigned long offset;
 340         int sb2i;  /* array index of the secondary superblock */
 341         int ret = 0;
 342
 343         /* nilfs->ns_sem must be locked by the caller. */
 344         if (nilfs->ns_sbh[1] &&
 345             nilfs->ns_sbh[1]->b_blocknr > nilfs->ns_first_data_block) {
 346                 sb2i = 1;
 347                 blocknr = nilfs->ns_sbh[1]->b_blocknr;
 348         } else if (nilfs->ns_sbh[0]->b_blocknr > nilfs->ns_first_data_block) {
 349                 sb2i = 0;
 350                 blocknr = nilfs->ns_sbh[0]->b_blocknr;
 351         } else {
 352                 sb2i = -1;
 353                 blocknr = 0;
 354         }
 355         if (sb2i >= 0 && (u64)blocknr << nilfs->ns_blocksize_bits == sb2off)
 356                 goto out;  /* super block location is unchanged */
 357
 358         /* Get new super block buffer */
 359         newblocknr = sb2off >> nilfs->ns_blocksize_bits;
 360         offset = sb2off & (nilfs->ns_blocksize - 1);
 361         nsbh = sb_getblk(sb, newblocknr);
 362         if (!nsbh) {
 363                 nilfs_msg(sb, KERN_WARNING,
 364                           "unable to move secondary superblock to block %llu",
 365                           (unsigned long long)newblocknr);
 366                 ret = -EIO;
 367                 goto out;
 368         }
 369         nsbp = (void *)nsbh->b_data + offset;
 370
 371         lock_buffer(nsbh);
 372         if (sb2i >= 0) {
 373                 /*
 374                  * The position of the second superblock only changes by 4KiB,
 375                  * which is larger than the maximum superblock data size
 376                  * (= 1KiB), so there is no need to use memmove() to allow
 377                  * overlap between source and destination.
 378                  */
 379                 memcpy(nsbp, nilfs->ns_sbp[sb2i], nilfs->ns_sbsize);
 380
 381                 /*
 382                  * Zero fill after copy to avoid overwriting in case of move
 383                  * within the same block.
 384                  */
 385                 memset(nsbh->b_data, 0, offset);
 386                 memset((void *)nsbp + nilfs->ns_sbsize, 0,
 387                        nsbh->b_size - offset - nilfs->ns_sbsize);
 388         } else {
 389                 memset(nsbh->b_data, 0, nsbh->b_size);
 390         }
 391         set_buffer_uptodate(nsbh);
 392         unlock_buffer(nsbh);
 393
 394         if (sb2i >= 0) {
 395                 brelse(nilfs->ns_sbh[sb2i]);
 396                 nilfs->ns_sbh[sb2i] = nsbh;
 397                 nilfs->ns_sbp[sb2i] = nsbp;
 398         } else if (nilfs->ns_sbh[0]->b_blocknr < nilfs->ns_first_data_block) {
 399                 /* secondary super block will be restored to index 1 */
 400                 nilfs->ns_sbh[1] = nsbh;
 401                 nilfs->ns_sbp[1] = nsbp;
 402         } else {
 403                 brelse(nsbh);
 404         }
 405 out:
 406         return ret;
 407 }
 408
 409 /**
 410  * nilfs_resize_fs - resize the filesystem
 411  * @sb: super block instance
 412  * @newsize: new size of the filesystem (in bytes)
 413  */
 414 int nilfs_resize_fs(struct super_block *sb, __u64 newsize)
 415 {
 416         struct the_nilfs *nilfs = sb->s_fs_info;
 417         struct nilfs_super_block **sbp;
 418         __u64 devsize, newnsegs;
 419         loff_t sb2off;
 420         int ret;
 421
 422         ret = -ERANGE;
 423         devsize = i_size_read(sb->s_bdev->bd_inode);
 424         if (newsize > devsize)
 425                 goto out;
 426
 427         /*
 428          * Prevent underflow in second superblock position calculation.
 429          * The exact minimum size check is done in nilfs_sufile_resize().
 430          */
 431         if (newsize < 4096) {
 432                 ret = -ENOSPC;
 433                 goto out;
 434         }
 435
 436         /*
 437          * Write lock is required to protect some functions depending
 438          * on the number of segments, the number of reserved segments,
 439          * and so forth.
 440          */
 441         down_write(&nilfs->ns_segctor_sem);
 442
 443         sb2off = NILFS_SB2_OFFSET_BYTES(newsize);
 444         newnsegs = sb2off >> nilfs->ns_blocksize_bits;
 445         do_div(newnsegs, nilfs->ns_blocks_per_segment);
 446
 447         ret = nilfs_sufile_resize(nilfs->ns_sufile, newnsegs);
 448         up_write(&nilfs->ns_segctor_sem);
 449         if (ret < 0)
 450                 goto out;
 451
 452         ret = nilfs_construct_segment(sb);
 453         if (ret < 0)
 454                 goto out;
 455
 456         down_write(&nilfs->ns_sem);
 457         nilfs_move_2nd_super(sb, sb2off);
 458         ret = -EIO;
 459         sbp = nilfs_prepare_super(sb, 0);
 460         if (likely(sbp)) {
 461                 nilfs_set_log_cursor(sbp[0], nilfs);
 462                 /*
 463                  * Drop NILFS_RESIZE_FS flag for compatibility with
 464                  * mount-time resize which may be implemented in a
 465                  * future release.
 466                  */
 467                 sbp[0]->s_state = cpu_to_le16(le16_to_cpu(sbp[0]->s_state) &
 468                                               ~NILFS_RESIZE_FS);
 469                 sbp[0]->s_dev_size = cpu_to_le64(newsize);
 470                 sbp[0]->s_nsegments = cpu_to_le64(nilfs->ns_nsegments);
 471                 if (sbp[1])
 472                         memcpy(sbp[1], sbp[0], nilfs->ns_sbsize);
 473                 ret = nilfs_commit_super(sb, NILFS_SB_COMMIT_ALL);
 474         }
 475         up_write(&nilfs->ns_sem);
 476
 477         /*
 478          * Reset the range of allocatable segments last.  This order
 479          * is important in the case of expansion because the secondary
 480          * superblock must be protected from log write until migration
 481          * completes.
 482          */
 483         if (!ret)
 484                 nilfs_sufile_set_alloc_range(nilfs->ns_sufile, 0, newnsegs - 1);
 485 out:
 486         return ret;
 487 }
 488
 489 static void nilfs_put_super(struct super_block *sb)
 490 {
 491         struct the_nilfs *nilfs = sb->s_fs_info;
 492
 493         nilfs_detach_log_writer(sb);
 494
 495         if (!sb_rdonly(sb)) {
 496                 down_write(&nilfs->ns_sem);
 497                 nilfs_cleanup_super(sb);
 498                 up_write(&nilfs->ns_sem);
 499         }
 500
 501         nilfs_sysfs_delete_device_group(nilfs);
 502         iput(nilfs->ns_sufile);
 503         iput(nilfs->ns_cpfile);
 504         iput(nilfs->ns_dat);
 505
 506         destroy_nilfs(nilfs);
 507         sb->s_fs_info = NULL;
 508 }
 509
 510 static int nilfs_sync_fs(struct super_block *sb, int wait)
 511 {
 512         struct the_nilfs *nilfs = sb->s_fs_info;
 513         struct nilfs_super_block **sbp;
 514         int err = 0;
 515
 516         /* This function is called when super block should be written back */
 517         if (wait)
 518                 err = nilfs_construct_segment(sb);
 519
 520         down_write(&nilfs->ns_sem);
 521         if (nilfs_sb_dirty(nilfs)) {
 522                 sbp = nilfs_prepare_super(sb, nilfs_sb_will_flip(nilfs));
 523                 if (likely(sbp)) {
 524                         nilfs_set_log_cursor(sbp[0], nilfs);
 525                         nilfs_commit_super(sb, NILFS_SB_COMMIT);
 526                 }
 527         }
 528         up_write(&nilfs->ns_sem);
 529
 530         if (!err)
 531                 err = nilfs_flush_device(nilfs);
 532
 533         return err;
 534 }
 535
 536 int nilfs_attach_checkpoint(struct super_block *sb, __u64 cno, int curr_mnt,
 537                             struct nilfs_root **rootp)
 538 {
 539         struct the_nilfs *nilfs = sb->s_fs_info;
 540         struct nilfs_root *root;
 541         struct nilfs_checkpoint *raw_cp;
 542         struct buffer_head *bh_cp;
 543         int err = -ENOMEM;
 544
 545         root = nilfs_find_or_create_root(
 546                 nilfs, curr_mnt ? NILFS_CPTREE_CURRENT_CNO : cno);
 547         if (!root)
 548                 return err;
 549
 550         if (root->ifile)
 551                 goto reuse; /* already attached checkpoint */
 552
 553         down_read(&nilfs->ns_segctor_sem);
 554         err = nilfs_cpfile_get_checkpoint(nilfs->ns_cpfile, cno, 0, &raw_cp,
 555                                           &bh_cp);
 556         up_read(&nilfs->ns_segctor_sem);
 557         if (unlikely(err)) {
 558                 if (err == -ENOENT || err == -EINVAL) {
 559                         nilfs_msg(sb, KERN_ERR,
 560                                   "Invalid checkpoint (checkpoint number=%llu)",
 561                                   (unsigned long long)cno);
 562                         err = -EINVAL;
 563                 }
 564                 goto failed;
 565         }
 566
 567         err = nilfs_ifile_read(sb, root, nilfs->ns_inode_size,
 568                                &raw_cp->cp_ifile_inode, &root->ifile);
 569         if (err)
 570                 goto failed_bh;
 571
 572         atomic64_set(&root->inodes_count,
 573                         le64_to_cpu(raw_cp->cp_inodes_count));
 574         atomic64_set(&root->blocks_count,
 575                         le64_to_cpu(raw_cp->cp_blocks_count));
 576
 577         nilfs_cpfile_put_checkpoint(nilfs->ns_cpfile, cno, bh_cp);
 578
 579  reuse:
 580         *rootp = root;
 581         return 0;
 582
 583  failed_bh:
 584         nilfs_cpfile_put_checkpoint(nilfs->ns_cpfile, cno, bh_cp);
 585  failed:
 586         nilfs_put_root(root);
 587
 588         return err;
 589 }
 590
 591 static int nilfs_freeze(struct super_block *sb)
 592 {
 593         struct the_nilfs *nilfs = sb->s_fs_info;
 594         int err;
 595
 596         if (sb_rdonly(sb))
 597                 return 0;
 598
 599         /* Mark super block clean */
 600         down_write(&nilfs->ns_sem);
 601         err = nilfs_cleanup_super(sb);
 602         up_write(&nilfs->ns_sem);
 603         return err;
 604 }
 605
 606 static int nilfs_unfreeze(struct super_block *sb)
 607 {
 608         struct the_nilfs *nilfs = sb->s_fs_info;
 609
 610         if (sb_rdonly(sb))
 611                 return 0;
 612
 613         down_write(&nilfs->ns_sem);
 614         nilfs_setup_super(sb, false);
 615         up_write(&nilfs->ns_sem);
 616         return 0;
 617 }
 618
 619 static int nilfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 620 {
 621         struct super_block *sb = dentry->d_sb;
 622         struct nilfs_root *root = NILFS_I(d_inode(dentry))->i_root;
 623         struct the_nilfs *nilfs = root->nilfs;
 624         u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
 625         unsigned long long blocks;
 626         unsigned long overhead;
 627         unsigned long nrsvblocks;
 628         sector_t nfreeblocks;
 629         u64 nmaxinodes, nfreeinodes;
 630         int err;
 631
 632         /*
 633          * Compute all of the segment blocks
 634          *
 635          * The blocks before first segment and after last segment
 636          * are excluded.
 637          */
 638         blocks = nilfs->ns_blocks_per_segment * nilfs->ns_nsegments
 639                 - nilfs->ns_first_data_block;
 640         nrsvblocks = nilfs->ns_nrsvsegs * nilfs->ns_blocks_per_segment;
 641
 642         /*
 643          * Compute the overhead
 644          *
 645          * When distributing meta data blocks outside segment structure,
 646          * We must count them as the overhead.
 647          */
 648         overhead = 0;
 649
 650         err = nilfs_count_free_blocks(nilfs, &nfreeblocks);
 651         if (unlikely(err))
 652                 return err;
 653
 654         err = nilfs_ifile_count_free_inodes(root->ifile,
 655                                             &nmaxinodes, &nfreeinodes);
 656         if (unlikely(err)) {
 657                 nilfs_msg(sb, KERN_WARNING,
 658                           "failed to count free inodes: err=%d", err);
 659                 if (err == -ERANGE) {
 660                         /*
 661                          * If nilfs_palloc_count_max_entries() returns
 662                          * -ERANGE error code then we simply treat
 663                          * curent inodes count as maximum possible and
 664                          * zero as free inodes value.
 665                          */
 666                         nmaxinodes = atomic64_read(&root->inodes_count);
 667                         nfreeinodes = 0;
 668                         err = 0;
 669                 } else
 670                         return err;
 671         }
 672
 673         buf->f_type = NILFS_SUPER_MAGIC;
 674         buf->f_bsize = sb->s_blocksize;
 675         buf->f_blocks = blocks - overhead;
 676         buf->f_bfree = nfreeblocks;
 677         buf->f_bavail = (buf->f_bfree >= nrsvblocks) ?
 678                 (buf->f_bfree - nrsvblocks) : 0;
 679         buf->f_files = nmaxinodes;
 680         buf->f_ffree = nfreeinodes;
 681         buf->f_namelen = NILFS_NAME_LEN;
 682         buf->f_fsid.val[0] = (u32)id;
 683         buf->f_fsid.val[1] = (u32)(id >> 32);
 684
 685         return 0;
 686 }
 687
 688 static int nilfs_show_options(struct seq_file *seq, struct dentry *dentry)
 689 {
 690         struct super_block *sb = dentry->d_sb;
 691         struct the_nilfs *nilfs = sb->s_fs_info;
 692         struct nilfs_root *root = NILFS_I(d_inode(dentry))->i_root;
 693
 694         if (!nilfs_test_opt(nilfs, BARRIER))
 695                 seq_puts(seq, ",nobarrier");
 696         if (root->cno != NILFS_CPTREE_CURRENT_CNO)
 697                 seq_printf(seq, ",cp=%llu", (unsigned long long)root->cno);
 698         if (nilfs_test_opt(nilfs, ERRORS_PANIC))
 699                 seq_puts(seq, ",errors=panic");
 700         if (nilfs_test_opt(nilfs, ERRORS_CONT))
 701                 seq_puts(seq, ",errors=continue");
 702         if (nilfs_test_opt(nilfs, STRICT_ORDER))
 703                 seq_puts(seq, ",order=strict");
 704         if (nilfs_test_opt(nilfs, NORECOVERY))
 705                 seq_puts(seq, ",norecovery");
 706         if (nilfs_test_opt(nilfs, DISCARD))
 707                 seq_puts(seq, ",discard");
 708
 709         return 0;
 710 }
 711
 712 static const struct super_operations nilfs_sops = {
 713         .alloc_inode    = nilfs_alloc_inode,
 714         .free_inode     = nilfs_free_inode,
 715         .dirty_inode    = nilfs_dirty_inode,
 716         .evict_inode    = nilfs_evict_inode,
 717         .put_super      = nilfs_put_super,
 718         .sync_fs        = nilfs_sync_fs,
 719         .freeze_fs      = nilfs_freeze,
 720         .unfreeze_fs    = nilfs_unfreeze,
 721         .statfs         = nilfs_statfs,
 722         .remount_fs     = nilfs_remount,
 723         .show_options = nilfs_show_options
 724 };
 725
 726 enum {
 727         Opt_err_cont, Opt_err_panic, Opt_err_ro,
 728         Opt_barrier, Opt_nobarrier, Opt_snapshot, Opt_order, Opt_norecovery,
 729         Opt_discard, Opt_nodiscard, Opt_err,
 730 };
 731
 732 static match_table_t tokens = {
 733         {Opt_err_cont, "errors=continue"},
 734         {Opt_err_panic, "errors=panic"},
 735         {Opt_err_ro, "errors=remount-ro"},
 736         {Opt_barrier, "barrier"},
 737         {Opt_nobarrier, "nobarrier"},
 738         {Opt_snapshot, "cp=%u"},
 739         {Opt_order, "order=%s"},
 740         {Opt_norecovery, "norecovery"},
 741         {Opt_discard, "discard"},
 742         {Opt_nodiscard, "nodiscard"},
 743         {Opt_err, NULL}
 744 };
 745
 746 static int parse_options(char *options, struct super_block *sb, int is_remount)
 747 {
 748         struct the_nilfs *nilfs = sb->s_fs_info;
 749         char *p;
 750         substring_t args[MAX_OPT_ARGS];
 751
 752         if (!options)
 753                 return 1;
 754
 755         while ((p = strsep(&options, ",")) != NULL) {
 756                 int token;
 757
 758                 if (!*p)
 759                         continue;
 760
 761                 token = match_token(p, tokens, args);
 762                 switch (token) {
 763                 case Opt_barrier:
 764                         nilfs_set_opt(nilfs, BARRIER);
 765                         break;
 766                 case Opt_nobarrier:
 767                         nilfs_clear_opt(nilfs, BARRIER);
 768                         break;
 769                 case Opt_order:
 770                         if (strcmp(args[0].from, "relaxed") == 0)
 771                                 /* Ordered data semantics */
 772                                 nilfs_clear_opt(nilfs, STRICT_ORDER);
 773                         else if (strcmp(args[0].from, "strict") == 0)
 774                                 /* Strict in-order semantics */
 775                                 nilfs_set_opt(nilfs, STRICT_ORDER);
 776                         else
 777                                 return 0;
 778                         break;
 779                 case Opt_err_panic:
 780                         nilfs_write_opt(nilfs, ERROR_MODE, ERRORS_PANIC);
 781                         break;
 782                 case Opt_err_ro:
 783                         nilfs_write_opt(nilfs, ERROR_MODE, ERRORS_RO);
 784                         break;
 785                 case Opt_err_cont:
 786                         nilfs_write_opt(nilfs, ERROR_MODE, ERRORS_CONT);
 787                         break;
 788                 case Opt_snapshot:
 789                         if (is_remount) {
 790                                 nilfs_msg(sb, KERN_ERR,
 791                                           "\"%s\" option is invalid for remount",
 792                                           p);
 793                                 return 0;
 794                         }
 795                         break;
 796                 case Opt_norecovery:
 797                         nilfs_set_opt(nilfs, NORECOVERY);
 798                         break;
 799                 case Opt_discard:
 800                         nilfs_set_opt(nilfs, DISCARD);
 801                         break;
 802                 case Opt_nodiscard:
 803                         nilfs_clear_opt(nilfs, DISCARD);
 804                         break;
 805                 default:
 806                         nilfs_msg(sb, KERN_ERR,
 807                                   "unrecognized mount option \"%s\"", p);
 808                         return 0;
 809                 }
 810         }
 811         return 1;
 812 }
 813
 814 static inline void
 815 nilfs_set_default_options(struct super_block *sb,
 816                           struct nilfs_super_block *sbp)
 817 {
 818         struct the_nilfs *nilfs = sb->s_fs_info;
 819
 820         nilfs->ns_mount_opt =
 821                 NILFS_MOUNT_ERRORS_RO | NILFS_MOUNT_BARRIER;
 822 }
 823
 824 static int nilfs_setup_super(struct super_block *sb, int is_mount)
 825 {
 826         struct the_nilfs *nilfs = sb->s_fs_info;
 827         struct nilfs_super_block **sbp;
 828         int max_mnt_count;
 829         int mnt_count;
 830
 831         /* nilfs->ns_sem must be locked by the caller. */
 832         sbp = nilfs_prepare_super(sb, 0);
 833         if (!sbp)
 834                 return -EIO;
 835
 836         if (!is_mount)
 837                 goto skip_mount_setup;
 838
 839         max_mnt_count = le16_to_cpu(sbp[0]->s_max_mnt_count);
 840         mnt_count = le16_to_cpu(sbp[0]->s_mnt_count);
 841
 842         if (nilfs->ns_mount_state & NILFS_ERROR_FS) {
 843                 nilfs_msg(sb, KERN_WARNING, "mounting fs with errors");
 844 #if 0
 845         } else if (max_mnt_count >= 0 && mnt_count >= max_mnt_count) {
 846                 nilfs_msg(sb, KERN_WARNING, "maximal mount count reached");
 847 #endif
 848         }
 849         if (!max_mnt_count)
 850                 sbp[0]->s_max_mnt_count = cpu_to_le16(NILFS_DFL_MAX_MNT_COUNT);
 851
 852         sbp[0]->s_mnt_count = cpu_to_le16(mnt_count + 1);
 853         sbp[0]->s_mtime = cpu_to_le64(ktime_get_real_seconds());
 854
 855 skip_mount_setup:
 856         sbp[0]->s_state =
 857                 cpu_to_le16(le16_to_cpu(sbp[0]->s_state) & ~NILFS_VALID_FS);
 858         /* synchronize sbp[1] with sbp[0] */
 859         if (sbp[1])
 860                 memcpy(sbp[1], sbp[0], nilfs->ns_sbsize);
 861         return nilfs_commit_super(sb, NILFS_SB_COMMIT_ALL);
 862 }
 863
 864 struct nilfs_super_block *nilfs_read_super_block(struct super_block *sb,
 865                                                  u64 pos, int blocksize,
 866                                                  struct buffer_head **pbh)
 867 {
 868         unsigned long long sb_index = pos;
 869         unsigned long offset;
 870
 871         offset = do_div(sb_index, blocksize);
 872         *pbh = sb_bread(sb, sb_index);
 873         if (!*pbh)
 874                 return NULL;
 875         return (struct nilfs_super_block *)((char *)(*pbh)->b_data + offset);
 876 }
 877
 878 int nilfs_store_magic_and_option(struct super_block *sb,
 879                                  struct nilfs_super_block *sbp,
 880                                  char *data)
 881 {
 882         struct the_nilfs *nilfs = sb->s_fs_info;
 883
 884         sb->s_magic = le16_to_cpu(sbp->s_magic);
 885
 886         /* FS independent flags */
 887 #ifdef NILFS_ATIME_DISABLE
 888         sb->s_flags |= SB_NOATIME;
 889 #endif
 890
 891         nilfs_set_default_options(sb, sbp);
 892
 893         nilfs->ns_resuid = le16_to_cpu(sbp->s_def_resuid);
 894         nilfs->ns_resgid = le16_to_cpu(sbp->s_def_resgid);
 895         nilfs->ns_interval = le32_to_cpu(sbp->s_c_interval);
 896         nilfs->ns_watermark = le32_to_cpu(sbp->s_c_block_max);
 897
 898         return !parse_options(data, sb, 0) ? -EINVAL : 0;
 899 }
 900
 901 int nilfs_check_feature_compatibility(struct super_block *sb,
 902                                       struct nilfs_super_block *sbp)
 903 {
 904         __u64 features;
 905
 906         features = le64_to_cpu(sbp->s_feature_incompat) &
 907                 ~NILFS_FEATURE_INCOMPAT_SUPP;
 908         if (features) {
 909                 nilfs_msg(sb, KERN_ERR,
 910                           "couldn't mount because of unsupported optional features (%llx)",
 911                           (unsigned long long)features);
 912                 return -EINVAL;
 913         }
 914         features = le64_to_cpu(sbp->s_feature_compat_ro) &
 915                 ~NILFS_FEATURE_COMPAT_RO_SUPP;
 916         if (!sb_rdonly(sb) && features) {
 917                 nilfs_msg(sb, KERN_ERR,
 918                           "couldn't mount RDWR because of unsupported optional features (%llx)",
 919                           (unsigned long long)features);
 920                 return -EINVAL;
 921         }
 922         return 0;
 923 }
 924
 925 static int nilfs_get_root_dentry(struct super_block *sb,
 926                                  struct nilfs_root *root,
 927                                  struct dentry **root_dentry)
 928 {
 929         struct inode *inode;
 930         struct dentry *dentry;
 931         int ret = 0;
 932
 933         inode = nilfs_iget(sb, root, NILFS_ROOT_INO);
 934         if (IS_ERR(inode)) {
 935                 ret = PTR_ERR(inode);
 936                 nilfs_msg(sb, KERN_ERR, "error %d getting root inode", ret);
 937                 goto out;
 938         }
 939         if (!S_ISDIR(inode->i_mode) || !inode->i_blocks || !inode->i_size) {
 940                 iput(inode);
 941                 nilfs_msg(sb, KERN_ERR, "corrupt root inode");
 942                 ret = -EINVAL;
 943                 goto out;
 944         }
 945
 946         if (root->cno == NILFS_CPTREE_CURRENT_CNO) {
 947                 dentry = d_find_alias(inode);
 948                 if (!dentry) {
 949                         dentry = d_make_root(inode);
 950                         if (!dentry) {
 951                                 ret = -ENOMEM;
 952                                 goto failed_dentry;
 953                         }
 954                 } else {
 955                         iput(inode);
 956                 }
 957         } else {
 958                 dentry = d_obtain_root(inode);
 959                 if (IS_ERR(dentry)) {
 960                         ret = PTR_ERR(dentry);
 961                         goto failed_dentry;
 962                 }
 963         }
 964         *root_dentry = dentry;
 965  out:
 966         return ret;
 967
 968  failed_dentry:
 969         nilfs_msg(sb, KERN_ERR, "error %d getting root dentry", ret);
 970         goto out;
 971 }
 972
 973 static int nilfs_attach_snapshot(struct super_block *s, __u64 cno,
 974                                  struct dentry **root_dentry)
 975 {
 976         struct the_nilfs *nilfs = s->s_fs_info;
 977         struct nilfs_root *root;
 978         int ret;
 979
 980         mutex_lock(&nilfs->ns_snapshot_mount_mutex);
 981
 982         down_read(&nilfs->ns_segctor_sem);
 983         ret = nilfs_cpfile_is_snapshot(nilfs->ns_cpfile, cno);
 984         up_read(&nilfs->ns_segctor_sem);
 985         if (ret < 0) {
 986                 ret = (ret == -ENOENT) ? -EINVAL : ret;
 987                 goto out;
 988         } else if (!ret) {
 989                 nilfs_msg(s, KERN_ERR,
 990                           "The specified checkpoint is not a snapshot (checkpoint number=%llu)",
 991                           (unsigned long long)cno);
 992                 ret = -EINVAL;
 993                 goto out;
 994         }
 995
 996         ret = nilfs_attach_checkpoint(s, cno, false, &root);
 997         if (ret) {
 998                 nilfs_msg(s, KERN_ERR,
 999                           "error %d while loading snapshot (checkpoint number=%llu)",
1000                           ret, (unsigned long long)cno);
1001                 goto out;
1002         }
1003         ret = nilfs_get_root_dentry(s, root, root_dentry);
1004         nilfs_put_root(root);
1005  out:
1006         mutex_unlock(&nilfs->ns_snapshot_mount_mutex);
1007         return ret;
1008 }
1009
1010 /**
1011  * nilfs_tree_is_busy() - try to shrink dentries of a checkpoint
1012  * @root_dentry: root dentry of the tree to be shrunk
1013  *
1014  * This function returns true if the tree was in-use.
1015  */
1016 static bool nilfs_tree_is_busy(struct dentry *root_dentry)
1017 {
1018         shrink_dcache_parent(root_dentry);
1019         return d_count(root_dentry) > 1;
1020 }
1021
1022 int nilfs_checkpoint_is_mounted(struct super_block *sb, __u64 cno)
1023 {
1024         struct the_nilfs *nilfs = sb->s_fs_info;
1025         struct nilfs_root *root;
1026         struct inode *inode;
1027         struct dentry *dentry;
1028         int ret;
1029
1030         if (cno > nilfs->ns_cno)
1031                 return false;
1032
1033         if (cno >= nilfs_last_cno(nilfs))
1034                 return true;    /* protect recent checkpoints */
1035
1036         ret = false;
1037         root = nilfs_lookup_root(nilfs, cno);
1038         if (root) {
1039                 inode = nilfs_ilookup(sb, root, NILFS_ROOT_INO);
1040                 if (inode) {
1041                         dentry = d_find_alias(inode);
1042                         if (dentry) {
1043                                 ret = nilfs_tree_is_busy(dentry);
1044                                 dput(dentry);
1045                         }
1046                         iput(inode);
1047                 }
1048                 nilfs_put_root(root);
1049         }
1050         return ret;
1051 }
1052
1053 /**
1054  * nilfs_fill_super() - initialize a super block instance
1055  * @sb: super_block
1056  * @data: mount options
1057  * @silent: silent mode flag
1058  *
1059  * This function is called exclusively by nilfs->ns_mount_mutex.
1060  * So, the recovery process is protected from other simultaneous mounts.
1061  */
1062 static int
1063 nilfs_fill_super(struct super_block *sb, void *data, int silent)
1064 {
1065         struct the_nilfs *nilfs;
1066         struct nilfs_root *fsroot;
1067         __u64 cno;
1068         int err;
1069
1070         nilfs = alloc_nilfs(sb);
1071         if (!nilfs)
1072                 return -ENOMEM;
1073
1074         sb->s_fs_info = nilfs;
1075
1076         err = init_nilfs(nilfs, sb, (char *)data);
1077         if (err)
1078                 goto failed_nilfs;
1079
1080         sb->s_op = &nilfs_sops;
1081         sb->s_export_op = &nilfs_export_ops;
1082         sb->s_root = NULL;
1083         sb->s_time_gran = 1;
1084         sb->s_max_links = NILFS_LINK_MAX;
1085
1086         sb->s_bdi = bdi_get(sb->s_bdev->bd_bdi);
1087
1088         err = load_nilfs(nilfs, sb);
1089         if (err)
1090                 goto failed_nilfs;
1091
1092         cno = nilfs_last_cno(nilfs);
1093         err = nilfs_attach_checkpoint(sb, cno, true, &fsroot);
1094         if (err) {
1095                 nilfs_msg(sb, KERN_ERR,
1096                           "error %d while loading last checkpoint (checkpoint number=%llu)",
1097                           err, (unsigned long long)cno);
1098                 goto failed_unload;
1099         }
1100
1101         if (!sb_rdonly(sb)) {
1102                 err = nilfs_attach_log_writer(sb, fsroot);
1103                 if (err)
1104                         goto failed_checkpoint;
1105         }
1106
1107         err = nilfs_get_root_dentry(sb, fsroot, &sb->s_root);
1108         if (err)
1109                 goto failed_segctor;
1110
1111         nilfs_put_root(fsroot);
1112
1113         if (!sb_rdonly(sb)) {
1114                 down_write(&nilfs->ns_sem);
1115                 nilfs_setup_super(sb, true);
1116                 up_write(&nilfs->ns_sem);
1117         }
1118
1119         return 0;
1120
1121  failed_segctor:
1122         nilfs_detach_log_writer(sb);
1123
1124  failed_checkpoint:
1125         nilfs_put_root(fsroot);
1126
1127  failed_unload:
1128         nilfs_sysfs_delete_device_group(nilfs);
1129         iput(nilfs->ns_sufile);
1130         iput(nilfs->ns_cpfile);
1131         iput(nilfs->ns_dat);
1132
1133  failed_nilfs:
1134         destroy_nilfs(nilfs);
1135         return err;
1136 }
1137
1138 static int nilfs_remount(struct super_block *sb, int *flags, char *data)
1139 {
1140         struct the_nilfs *nilfs = sb->s_fs_info;
1141         unsigned long old_sb_flags;
1142         unsigned long old_mount_opt;
1143         int err;
1144
1145         sync_filesystem(sb);
1146         old_sb_flags = sb->s_flags;
1147         old_mount_opt = nilfs->ns_mount_opt;
1148
1149         if (!parse_options(data, sb, 1)) {
1150                 err = -EINVAL;
1151                 goto restore_opts;
1152         }
1153         sb->s_flags = (sb->s_flags & ~SB_POSIXACL);
1154
1155         err = -EINVAL;
1156
1157         if (!nilfs_valid_fs(nilfs)) {
1158                 nilfs_msg(sb, KERN_WARNING,
1159                           "couldn't remount because the filesystem is in an incomplete recovery state");
1160                 goto restore_opts;
1161         }
1162
1163         if ((bool)(*flags & SB_RDONLY) == sb_rdonly(sb))
1164                 goto out;
1165         if (*flags & SB_RDONLY) {
1166                 sb->s_flags |= SB_RDONLY;
1167
1168                 /*
1169                  * Remounting a valid RW partition RDONLY, so set
1170                  * the RDONLY flag and then mark the partition as valid again.
1171                  */
1172                 down_write(&nilfs->ns_sem);
1173                 nilfs_cleanup_super(sb);
1174                 up_write(&nilfs->ns_sem);
1175         } else {
1176                 __u64 features;
1177                 struct nilfs_root *root;
1178
1179                 /*
1180                  * Mounting a RDONLY partition read-write, so reread and
1181                  * store the current valid flag.  (It may have been changed
1182                  * by fsck since we originally mounted the partition.)
1183                  */
1184                 down_read(&nilfs->ns_sem);
1185                 features = le64_to_cpu(nilfs->ns_sbp[0]->s_feature_compat_ro) &
1186                         ~NILFS_FEATURE_COMPAT_RO_SUPP;
1187                 up_read(&nilfs->ns_sem);
1188                 if (features) {
1189                         nilfs_msg(sb, KERN_WARNING,
1190                                   "couldn't remount RDWR because of unsupported optional features (%llx)",
1191                                   (unsigned long long)features);
1192                         err = -EROFS;
1193                         goto restore_opts;
1194                 }
1195
1196                 sb->s_flags &= ~SB_RDONLY;
1197
1198                 root = NILFS_I(d_inode(sb->s_root))->i_root;
1199                 err = nilfs_attach_log_writer(sb, root);
1200                 if (err)
1201                         goto restore_opts;
1202
1203                 down_write(&nilfs->ns_sem);
1204                 nilfs_setup_super(sb, true);
1205                 up_write(&nilfs->ns_sem);
1206         }
1207  out:
1208         return 0;
1209
1210  restore_opts:
1211         sb->s_flags = old_sb_flags;
1212         nilfs->ns_mount_opt = old_mount_opt;
1213         return err;
1214 }
1215
1216 struct nilfs_super_data {
1217         struct block_device *bdev;
1218         __u64 cno;
1219         int flags;
1220 };
1221
1222 static int nilfs_parse_snapshot_option(const char *option,
1223                                        const substring_t *arg,
1224                                        struct nilfs_super_data *sd)
1225 {
1226         unsigned long long val;
1227         const char *msg = NULL;
1228         int err;
1229
1230         if (!(sd->flags & SB_RDONLY)) {
1231                 msg = "read-only option is not specified";
1232                 goto parse_error;
1233         }
1234
1235         err = kstrtoull(arg->from, 0, &val);
1236         if (err) {
1237                 if (err == -ERANGE)
1238                         msg = "too large checkpoint number";
1239                 else
1240                         msg = "malformed argument";
1241                 goto parse_error;
1242         } else if (val == 0) {
1243                 msg = "invalid checkpoint number 0";
1244                 goto parse_error;
1245         }
1246         sd->cno = val;
1247         return 0;
1248
1249 parse_error:
1250         nilfs_msg(NULL, KERN_ERR, "invalid option \"%s\": %s", option, msg);
1251         return 1;
1252 }
1253
1254 /**
1255  * nilfs_identify - pre-read mount options needed to identify mount instance
1256  * @data: mount options
1257  * @sd: nilfs_super_data
1258  */
1259 static int nilfs_identify(char *data, struct nilfs_super_data *sd)
1260 {
1261         char *p, *options = data;
1262         substring_t args[MAX_OPT_ARGS];
1263         int token;
1264         int ret = 0;
1265
1266         do {
1267                 p = strsep(&options, ",");
1268                 if (p != NULL && *p) {
1269                         token = match_token(p, tokens, args);
1270                         if (token == Opt_snapshot)
1271                                 ret = nilfs_parse_snapshot_option(p, &args[0],
1272                                                                   sd);
1273                 }
1274                 if (!options)
1275                         break;
1276                 BUG_ON(options == data);
1277                 *(options - 1) = ',';
1278         } while (!ret);
1279         return ret;
1280 }
1281
1282 static int nilfs_set_bdev_super(struct super_block *s, void *data)
1283 {
1284         s->s_bdev = data;
1285         s->s_dev = s->s_bdev->bd_dev;
1286         return 0;
1287 }
1288
1289 static int nilfs_test_bdev_super(struct super_block *s, void *data)
1290 {
1291         return (void *)s->s_bdev == data;
1292 }
1293
1294 static struct dentry *
1295 nilfs_mount(struct file_system_type *fs_type, int flags,
1296              const char *dev_name, void *data)
1297 {
1298         struct nilfs_super_data sd;
1299         struct super_block *s;
1300         fmode_t mode = FMODE_READ | FMODE_EXCL;
1301         struct dentry *root_dentry;
1302         int err, s_new = false;
1303
1304         if (!(flags & SB_RDONLY))
1305                 mode |= FMODE_WRITE;
1306
1307         sd.bdev = blkdev_get_by_path(dev_name, mode, fs_type);
1308         if (IS_ERR(sd.bdev))
1309                 return ERR_CAST(sd.bdev);
1310
1311         sd.cno = 0;
1312         sd.flags = flags;
1313         if (nilfs_identify((char *)data, &sd)) {
1314                 err = -EINVAL;
1315                 goto failed;
1316         }
1317
1318         /*
1319          * once the super is inserted into the list by sget, s_umount
1320          * will protect the lockfs code from trying to start a snapshot
1321          * while we are mounting
1322          */
1323         mutex_lock(&sd.bdev->bd_fsfreeze_mutex);
1324         if (sd.bdev->bd_fsfreeze_count > 0) {
1325                 mutex_unlock(&sd.bdev->bd_fsfreeze_mutex);
1326                 err = -EBUSY;
1327                 goto failed;
1328         }
1329         s = sget(fs_type, nilfs_test_bdev_super, nilfs_set_bdev_super, flags,
1330                  sd.bdev);
1331         mutex_unlock(&sd.bdev->bd_fsfreeze_mutex);
1332         if (IS_ERR(s)) {
1333                 err = PTR_ERR(s);
1334                 goto failed;
1335         }
1336
1337         if (!s->s_root) {
1338                 s_new = true;
1339
1340                 /* New superblock instance created */
1341                 s->s_mode = mode;
1342                 snprintf(s->s_id, sizeof(s->s_id), "%pg", sd.bdev);
1343                 sb_set_blocksize(s, block_size(sd.bdev));
1344
1345                 err = nilfs_fill_super(s, data, flags & SB_SILENT ? 1 : 0);
1346                 if (err)
1347                         goto failed_super;
1348
1349                 s->s_flags |= SB_ACTIVE;
1350         } else if (!sd.cno) {
1351                 if (nilfs_tree_is_busy(s->s_root)) {
1352                         if ((flags ^ s->s_flags) & SB_RDONLY) {
1353                                 nilfs_msg(s, KERN_ERR,
1354                                           "the device already has a %s mount.",
1355                                           sb_rdonly(s) ? "read-only" : "read/write");
1356                                 err = -EBUSY;
1357                                 goto failed_super;
1358                         }
1359                 } else {
1360                         /*
1361                          * Try remount to setup mount states if the current
1362                          * tree is not mounted and only snapshots use this sb.
1363                          */
1364                         err = nilfs_remount(s, &flags, data);
1365                         if (err)
1366                                 goto failed_super;
1367                 }
1368         }
1369
1370         if (sd.cno) {
1371                 err = nilfs_attach_snapshot(s, sd.cno, &root_dentry);
1372                 if (err)
1373                         goto failed_super;
1374         } else {
1375                 root_dentry = dget(s->s_root);
1376         }
1377
1378         if (!s_new)
1379                 blkdev_put(sd.bdev, mode);
1380
1381         return root_dentry;
1382
1383  failed_super:
1384         deactivate_locked_super(s);
1385
1386  failed:
1387         if (!s_new)
1388                 blkdev_put(sd.bdev, mode);
1389         return ERR_PTR(err);
1390 }
1391
1392 struct file_system_type nilfs_fs_type = {
1393         .owner    = THIS_MODULE,
1394         .name     = "nilfs2",
1395         .mount    = nilfs_mount,
1396         .kill_sb  = kill_block_super,
1397         .fs_flags = FS_REQUIRES_DEV,
1398 };
1399 MODULE_ALIAS_FS("nilfs2");
1400
1401 static void nilfs_inode_init_once(void *obj)
1402 {
1403         struct nilfs_inode_info *ii = obj;
1404
1405         INIT_LIST_HEAD(&ii->i_dirty);
1406 #ifdef CONFIG_NILFS_XATTR
1407         init_rwsem(&ii->xattr_sem);
1408 #endif
1409         inode_init_once(&ii->vfs_inode);
1410 }
1411
1412 static void nilfs_segbuf_init_once(void *obj)
1413 {
1414         memset(obj, 0, sizeof(struct nilfs_segment_buffer));
1415 }
1416
1417 static void nilfs_destroy_cachep(void)
1418 {
1419         /*
1420          * Make sure all delayed rcu free inodes are flushed before we
1421          * destroy cache.
1422          */
1423         rcu_barrier();
1424
1425         kmem_cache_destroy(nilfs_inode_cachep);
1426         kmem_cache_destroy(nilfs_transaction_cachep);
1427         kmem_cache_destroy(nilfs_segbuf_cachep);
1428         kmem_cache_destroy(nilfs_btree_path_cache);
1429 }
1430
1431 static int __init nilfs_init_cachep(void)
1432 {
1433         nilfs_inode_cachep = kmem_cache_create("nilfs2_inode_cache",
1434                         sizeof(struct nilfs_inode_info), 0,
1435                         SLAB_RECLAIM_ACCOUNT|SLAB_ACCOUNT,
1436                         nilfs_inode_init_once);
1437         if (!nilfs_inode_cachep)
1438                 goto fail;
1439
1440         nilfs_transaction_cachep = kmem_cache_create("nilfs2_transaction_cache",
1441                         sizeof(struct nilfs_transaction_info), 0,
1442                         SLAB_RECLAIM_ACCOUNT, NULL);
1443         if (!nilfs_transaction_cachep)
1444                 goto fail;
1445
1446         nilfs_segbuf_cachep = kmem_cache_create("nilfs2_segbuf_cache",
1447                         sizeof(struct nilfs_segment_buffer), 0,
1448                         SLAB_RECLAIM_ACCOUNT, nilfs_segbuf_init_once);
1449         if (!nilfs_segbuf_cachep)
1450                 goto fail;
1451
1452         nilfs_btree_path_cache = kmem_cache_create("nilfs2_btree_path_cache",
1453                         sizeof(struct nilfs_btree_path) * NILFS_BTREE_LEVEL_MAX,
1454                         0, 0, NULL);
1455         if (!nilfs_btree_path_cache)
1456                 goto fail;
1457
1458         return 0;
1459
1460 fail:
1461         nilfs_destroy_cachep();
1462         return -ENOMEM;
1463 }
1464
1465 static int __init init_nilfs_fs(void)
1466 {
1467         int err;
1468
1469         err = nilfs_init_cachep();
1470         if (err)
1471                 goto fail;
1472
1473         err = nilfs_sysfs_init();
1474         if (err)
1475                 goto free_cachep;
1476
1477         err = register_filesystem(&nilfs_fs_type);
1478         if (err)
1479                 goto deinit_sysfs_entry;
1480
1481         printk(KERN_INFO "NILFS version 2 loaded\n");
1482         return 0;
1483
1484 deinit_sysfs_entry:
1485         nilfs_sysfs_exit();
1486 free_cachep:
1487         nilfs_destroy_cachep();
1488 fail:
1489         return err;
1490 }
1491
1492 static void __exit exit_nilfs_fs(void)
1493 {
1494         nilfs_destroy_cachep();
1495         nilfs_sysfs_exit();
1496         unregister_filesystem(&nilfs_fs_type);
1497 }
1498
1499 module_init(init_nilfs_fs)
1500 module_exit(exit_nilfs_fs)