fs/nilfs2/the_nilfs.c

   1 /*
   2  * the_nilfs.c - the_nilfs shared structure.
   3  *
   4  * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  19  *
  20  * Written by Ryusuke Konishi <ryusuke@osrg.net>
  21  *
  22  */
  23
  24 #include <linux/buffer_head.h>
  25 #include <linux/slab.h>
  26 #include <linux/blkdev.h>
  27 #include <linux/backing-dev.h>
  28 #include <linux/random.h>
  29 #include <linux/crc32.h>
  30 #include "nilfs.h"
  31 #include "segment.h"
  32 #include "alloc.h"
  33 #include "cpfile.h"
  34 #include "sufile.h"
  35 #include "dat.h"
  36 #include "segbuf.h"
  37
  38
  39 static int nilfs_valid_sb(struct nilfs_super_block *sbp);
  40
  41 void nilfs_set_last_segment(struct the_nilfs *nilfs,
  42                             sector_t start_blocknr, u64 seq, __u64 cno)
  43 {
  44         spin_lock(&nilfs->ns_last_segment_lock);
  45         nilfs->ns_last_pseg = start_blocknr;
  46         nilfs->ns_last_seq = seq;
  47         nilfs->ns_last_cno = cno;
  48
  49         if (!nilfs_sb_dirty(nilfs)) {
  50                 if (nilfs->ns_prev_seq == nilfs->ns_last_seq)
  51                         goto stay_cursor;
  52
  53                 set_nilfs_sb_dirty(nilfs);
  54         }
  55         nilfs->ns_prev_seq = nilfs->ns_last_seq;
  56
  57  stay_cursor:
  58         spin_unlock(&nilfs->ns_last_segment_lock);
  59 }
  60
  61 /**
  62  * alloc_nilfs - allocate a nilfs object
  63  * @bdev: block device to which the_nilfs is related
  64  *
  65  * Return Value: On success, pointer to the_nilfs is returned.
  66  * On error, NULL is returned.
  67  */
  68 struct the_nilfs *alloc_nilfs(struct block_device *bdev)
  69 {
  70         struct the_nilfs *nilfs;
  71
  72         nilfs = kzalloc(sizeof(*nilfs), GFP_KERNEL);
  73         if (!nilfs)
  74                 return NULL;
  75
  76         nilfs->ns_bdev = bdev;
  77         atomic_set(&nilfs->ns_ndirtyblks, 0);
  78         init_rwsem(&nilfs->ns_sem);
  79         INIT_LIST_HEAD(&nilfs->ns_dirty_files);
  80         INIT_LIST_HEAD(&nilfs->ns_gc_inodes);
  81         spin_lock_init(&nilfs->ns_inode_lock);
  82         spin_lock_init(&nilfs->ns_next_gen_lock);
  83         spin_lock_init(&nilfs->ns_last_segment_lock);
  84         nilfs->ns_cptree = RB_ROOT;
  85         spin_lock_init(&nilfs->ns_cptree_lock);
  86         init_rwsem(&nilfs->ns_segctor_sem);
  87
  88         return nilfs;
  89 }
  90
  91 /**
  92  * destroy_nilfs - destroy nilfs object
  93  * @nilfs: nilfs object to be released
  94  */
  95 void destroy_nilfs(struct the_nilfs *nilfs)
  96 {
  97         might_sleep();
  98         if (nilfs_init(nilfs)) {
  99                 brelse(nilfs->ns_sbh[0]);
 100                 brelse(nilfs->ns_sbh[1]);
 101         }
 102         kfree(nilfs);
 103 }
 104
 105 static int nilfs_load_super_root(struct the_nilfs *nilfs,
 106                                  struct super_block *sb, sector_t sr_block)
 107 {
 108         struct buffer_head *bh_sr;
 109         struct nilfs_super_root *raw_sr;
 110         struct nilfs_super_block **sbp = nilfs->ns_sbp;
 111         struct nilfs_inode *rawi;
 112         unsigned dat_entry_size, segment_usage_size, checkpoint_size;
 113         unsigned inode_size;
 114         int err;
 115
 116         err = nilfs_read_super_root_block(nilfs, sr_block, &bh_sr, 1);
 117         if (unlikely(err))
 118                 return err;
 119
 120         down_read(&nilfs->ns_sem);
 121         dat_entry_size = le16_to_cpu(sbp[0]->s_dat_entry_size);
 122         checkpoint_size = le16_to_cpu(sbp[0]->s_checkpoint_size);
 123         segment_usage_size = le16_to_cpu(sbp[0]->s_segment_usage_size);
 124         up_read(&nilfs->ns_sem);
 125
 126         inode_size = nilfs->ns_inode_size;
 127
 128         rawi = (void *)bh_sr->b_data + NILFS_SR_DAT_OFFSET(inode_size);
 129         err = nilfs_dat_read(sb, dat_entry_size, rawi, &nilfs->ns_dat);
 130         if (err)
 131                 goto failed;
 132
 133         rawi = (void *)bh_sr->b_data + NILFS_SR_CPFILE_OFFSET(inode_size);
 134         err = nilfs_cpfile_read(sb, checkpoint_size, rawi, &nilfs->ns_cpfile);
 135         if (err)
 136                 goto failed_dat;
 137
 138         rawi = (void *)bh_sr->b_data + NILFS_SR_SUFILE_OFFSET(inode_size);
 139         err = nilfs_sufile_read(sb, segment_usage_size, rawi,
 140                                 &nilfs->ns_sufile);
 141         if (err)
 142                 goto failed_cpfile;
 143
 144         raw_sr = (struct nilfs_super_root *)bh_sr->b_data;
 145         nilfs->ns_nongc_ctime = le64_to_cpu(raw_sr->sr_nongc_ctime);
 146
 147  failed:
 148         brelse(bh_sr);
 149         return err;
 150
 151  failed_cpfile:
 152         iput(nilfs->ns_cpfile);
 153
 154  failed_dat:
 155         iput(nilfs->ns_dat);
 156         goto failed;
 157 }
 158
 159 static void nilfs_init_recovery_info(struct nilfs_recovery_info *ri)
 160 {
 161         memset(ri, 0, sizeof(*ri));
 162         INIT_LIST_HEAD(&ri->ri_used_segments);
 163 }
 164
 165 static void nilfs_clear_recovery_info(struct nilfs_recovery_info *ri)
 166 {
 167         nilfs_dispose_segment_list(&ri->ri_used_segments);
 168 }
 169
 170 /**
 171  * nilfs_store_log_cursor - load log cursor from a super block
 172  * @nilfs: nilfs object
 173  * @sbp: buffer storing super block to be read
 174  *
 175  * nilfs_store_log_cursor() reads the last position of the log
 176  * containing a super root from a given super block, and initializes
 177  * relevant information on the nilfs object preparatory for log
 178  * scanning and recovery.
 179  */
 180 static int nilfs_store_log_cursor(struct the_nilfs *nilfs,
 181                                   struct nilfs_super_block *sbp)
 182 {
 183         int ret = 0;
 184
 185         nilfs->ns_last_pseg = le64_to_cpu(sbp->s_last_pseg);
 186         nilfs->ns_last_cno = le64_to_cpu(sbp->s_last_cno);
 187         nilfs->ns_last_seq = le64_to_cpu(sbp->s_last_seq);
 188
 189         nilfs->ns_prev_seq = nilfs->ns_last_seq;
 190         nilfs->ns_seg_seq = nilfs->ns_last_seq;
 191         nilfs->ns_segnum =
 192                 nilfs_get_segnum_of_block(nilfs, nilfs->ns_last_pseg);
 193         nilfs->ns_cno = nilfs->ns_last_cno + 1;
 194         if (nilfs->ns_segnum >= nilfs->ns_nsegments) {
 195                 printk(KERN_ERR "NILFS invalid last segment number.\n");
 196                 ret = -EINVAL;
 197         }
 198         return ret;
 199 }
 200
 201 /**
 202  * load_nilfs - load and recover the nilfs
 203  * @nilfs: the_nilfs structure to be released
 204  * @sb: super block isntance used to recover past segment
 205  *
 206  * load_nilfs() searches and load the latest super root,
 207  * attaches the last segment, and does recovery if needed.
 208  * The caller must call this exclusively for simultaneous mounts.
 209  */
 210 int load_nilfs(struct the_nilfs *nilfs, struct super_block *sb)
 211 {
 212         struct nilfs_recovery_info ri;
 213         unsigned int s_flags = sb->s_flags;
 214         int really_read_only = bdev_read_only(nilfs->ns_bdev);
 215         int valid_fs = nilfs_valid_fs(nilfs);
 216         int err;
 217
 218         if (!valid_fs) {
 219                 printk(KERN_WARNING "NILFS warning: mounting unchecked fs\n");
 220                 if (s_flags & MS_RDONLY) {
 221                         printk(KERN_INFO "NILFS: INFO: recovery "
 222                                "required for readonly filesystem.\n");
 223                         printk(KERN_INFO "NILFS: write access will "
 224                                "be enabled during recovery.\n");
 225                 }
 226         }
 227
 228         nilfs_init_recovery_info(&ri);
 229
 230         err = nilfs_search_super_root(nilfs, &ri);
 231         if (unlikely(err)) {
 232                 struct nilfs_super_block **sbp = nilfs->ns_sbp;
 233                 int blocksize;
 234
 235                 if (err != -EINVAL)
 236                         goto scan_error;
 237
 238                 if (!nilfs_valid_sb(sbp[1])) {
 239                         printk(KERN_WARNING
 240                                "NILFS warning: unable to fall back to spare"
 241                                "super block\n");
 242                         goto scan_error;
 243                 }
 244                 printk(KERN_INFO
 245                        "NILFS: try rollback from an earlier position\n");
 246
 247                 /*
 248                  * restore super block with its spare and reconfigure
 249                  * relevant states of the nilfs object.
 250                  */
 251                 memcpy(sbp[0], sbp[1], nilfs->ns_sbsize);
 252                 nilfs->ns_crc_seed = le32_to_cpu(sbp[0]->s_crc_seed);
 253                 nilfs->ns_sbwtime = le64_to_cpu(sbp[0]->s_wtime);
 254
 255                 /* verify consistency between two super blocks */
 256                 blocksize = BLOCK_SIZE << le32_to_cpu(sbp[0]->s_log_block_size);
 257                 if (blocksize != nilfs->ns_blocksize) {
 258                         printk(KERN_WARNING
 259                                "NILFS warning: blocksize differs between "
 260                                "two super blocks (%d != %d)\n",
 261                                blocksize, nilfs->ns_blocksize);
 262                         goto scan_error;
 263                 }
 264
 265                 err = nilfs_store_log_cursor(nilfs, sbp[0]);
 266                 if (err)
 267                         goto scan_error;
 268
 269                 /* drop clean flag to allow roll-forward and recovery */
 270                 nilfs->ns_mount_state &= ~NILFS_VALID_FS;
 271                 valid_fs = 0;
 272
 273                 err = nilfs_search_super_root(nilfs, &ri);
 274                 if (err)
 275                         goto scan_error;
 276         }
 277
 278         err = nilfs_load_super_root(nilfs, sb, ri.ri_super_root);
 279         if (unlikely(err)) {
 280                 printk(KERN_ERR "NILFS: error loading super root.\n");
 281                 goto failed;
 282         }
 283
 284         if (valid_fs)
 285                 goto skip_recovery;
 286
 287         if (s_flags & MS_RDONLY) {
 288                 __u64 features;
 289
 290                 if (nilfs_test_opt(nilfs, NORECOVERY)) {
 291                         printk(KERN_INFO "NILFS: norecovery option specified. "
 292                                "skipping roll-forward recovery\n");
 293                         goto skip_recovery;
 294                 }
 295                 features = le64_to_cpu(nilfs->ns_sbp[0]->s_feature_compat_ro) &
 296                         ~NILFS_FEATURE_COMPAT_RO_SUPP;
 297                 if (features) {
 298                         printk(KERN_ERR "NILFS: couldn't proceed with "
 299                                "recovery because of unsupported optional "
 300                                "features (%llx)\n",
 301                                (unsigned long long)features);
 302                         err = -EROFS;
 303                         goto failed_unload;
 304                 }
 305                 if (really_read_only) {
 306                         printk(KERN_ERR "NILFS: write access "
 307                                "unavailable, cannot proceed.\n");
 308                         err = -EROFS;
 309                         goto failed_unload;
 310                 }
 311                 sb->s_flags &= ~MS_RDONLY;
 312         } else if (nilfs_test_opt(nilfs, NORECOVERY)) {
 313                 printk(KERN_ERR "NILFS: recovery cancelled because norecovery "
 314                        "option was specified for a read/write mount\n");
 315                 err = -EINVAL;
 316                 goto failed_unload;
 317         }
 318
 319         err = nilfs_salvage_orphan_logs(nilfs, sb, &ri);
 320         if (err)
 321                 goto failed_unload;
 322
 323         down_write(&nilfs->ns_sem);
 324         nilfs->ns_mount_state |= NILFS_VALID_FS; /* set "clean" flag */
 325         err = nilfs_cleanup_super(sb);
 326         up_write(&nilfs->ns_sem);
 327
 328         if (err) {
 329                 printk(KERN_ERR "NILFS: failed to update super block. "
 330                        "recovery unfinished.\n");
 331                 goto failed_unload;
 332         }
 333         printk(KERN_INFO "NILFS: recovery complete.\n");
 334
 335  skip_recovery:
 336         nilfs_clear_recovery_info(&ri);
 337         sb->s_flags = s_flags;
 338         return 0;
 339
 340  scan_error:
 341         printk(KERN_ERR "NILFS: error searching super root.\n");
 342         goto failed;
 343
 344  failed_unload:
 345         iput(nilfs->ns_cpfile);
 346         iput(nilfs->ns_sufile);
 347         iput(nilfs->ns_dat);
 348
 349  failed:
 350         nilfs_clear_recovery_info(&ri);
 351         sb->s_flags = s_flags;
 352         return err;
 353 }
 354
 355 static unsigned long long nilfs_max_size(unsigned int blkbits)
 356 {
 357         unsigned int max_bits;
 358         unsigned long long res = MAX_LFS_FILESIZE; /* page cache limit */
 359
 360         max_bits = blkbits + NILFS_BMAP_KEY_BIT; /* bmap size limit */
 361         if (max_bits < 64)
 362                 res = min_t(unsigned long long, res, (1ULL << max_bits) - 1);
 363         return res;
 364 }
 365
 366 /**
 367  * nilfs_nrsvsegs - calculate the number of reserved segments
 368  * @nilfs: nilfs object
 369  * @nsegs: total number of segments
 370  */
 371 unsigned long nilfs_nrsvsegs(struct the_nilfs *nilfs, unsigned long nsegs)
 372 {
 373         return max_t(unsigned long, NILFS_MIN_NRSVSEGS,
 374                      DIV_ROUND_UP(nsegs * nilfs->ns_r_segments_percentage,
 375                                   100));
 376 }
 377
 378 void nilfs_set_nsegments(struct the_nilfs *nilfs, unsigned long nsegs)
 379 {
 380         nilfs->ns_nsegments = nsegs;
 381         nilfs->ns_nrsvsegs = nilfs_nrsvsegs(nilfs, nsegs);
 382 }
 383
 384 static int nilfs_store_disk_layout(struct the_nilfs *nilfs,
 385                                    struct nilfs_super_block *sbp)
 386 {
 387         if (le32_to_cpu(sbp->s_rev_level) < NILFS_MIN_SUPP_REV) {
 388                 printk(KERN_ERR "NILFS: unsupported revision "
 389                        "(superblock rev.=%d.%d, current rev.=%d.%d). "
 390                        "Please check the version of mkfs.nilfs.\n",
 391                        le32_to_cpu(sbp->s_rev_level),
 392                        le16_to_cpu(sbp->s_minor_rev_level),
 393                        NILFS_CURRENT_REV, NILFS_MINOR_REV);
 394                 return -EINVAL;
 395         }
 396         nilfs->ns_sbsize = le16_to_cpu(sbp->s_bytes);
 397         if (nilfs->ns_sbsize > BLOCK_SIZE)
 398                 return -EINVAL;
 399
 400         nilfs->ns_inode_size = le16_to_cpu(sbp->s_inode_size);
 401         nilfs->ns_first_ino = le32_to_cpu(sbp->s_first_ino);
 402
 403         nilfs->ns_blocks_per_segment = le32_to_cpu(sbp->s_blocks_per_segment);
 404         if (nilfs->ns_blocks_per_segment < NILFS_SEG_MIN_BLOCKS) {
 405                 printk(KERN_ERR "NILFS: too short segment.\n");
 406                 return -EINVAL;
 407         }
 408
 409         nilfs->ns_first_data_block = le64_to_cpu(sbp->s_first_data_block);
 410         nilfs->ns_r_segments_percentage =
 411                 le32_to_cpu(sbp->s_r_segments_percentage);
 412         if (nilfs->ns_r_segments_percentage < 1 ||
 413             nilfs->ns_r_segments_percentage > 99) {
 414                 printk(KERN_ERR "NILFS: invalid reserved segments percentage.\n");
 415                 return -EINVAL;
 416         }
 417
 418         nilfs_set_nsegments(nilfs, le64_to_cpu(sbp->s_nsegments));
 419         nilfs->ns_crc_seed = le32_to_cpu(sbp->s_crc_seed);
 420         return 0;
 421 }
 422
 423 static int nilfs_valid_sb(struct nilfs_super_block *sbp)
 424 {
 425         static unsigned char sum[4];
 426         const int sumoff = offsetof(struct nilfs_super_block, s_sum);
 427         size_t bytes;
 428         u32 crc;
 429
 430         if (!sbp || le16_to_cpu(sbp->s_magic) != NILFS_SUPER_MAGIC)
 431                 return 0;
 432         bytes = le16_to_cpu(sbp->s_bytes);
 433         if (bytes > BLOCK_SIZE)
 434                 return 0;
 435         crc = crc32_le(le32_to_cpu(sbp->s_crc_seed), (unsigned char *)sbp,
 436                        sumoff);
 437         crc = crc32_le(crc, sum, 4);
 438         crc = crc32_le(crc, (unsigned char *)sbp + sumoff + 4,
 439                        bytes - sumoff - 4);
 440         return crc == le32_to_cpu(sbp->s_sum);
 441 }
 442
 443 static int nilfs_sb2_bad_offset(struct nilfs_super_block *sbp, u64 offset)
 444 {
 445         return offset < ((le64_to_cpu(sbp->s_nsegments) *
 446                           le32_to_cpu(sbp->s_blocks_per_segment)) <<
 447                          (le32_to_cpu(sbp->s_log_block_size) + 10));
 448 }
 449
 450 static void nilfs_release_super_block(struct the_nilfs *nilfs)
 451 {
 452         int i;
 453
 454         for (i = 0; i < 2; i++) {
 455                 if (nilfs->ns_sbp[i]) {
 456                         brelse(nilfs->ns_sbh[i]);
 457                         nilfs->ns_sbh[i] = NULL;
 458                         nilfs->ns_sbp[i] = NULL;
 459                 }
 460         }
 461 }
 462
 463 void nilfs_fall_back_super_block(struct the_nilfs *nilfs)
 464 {
 465         brelse(nilfs->ns_sbh[0]);
 466         nilfs->ns_sbh[0] = nilfs->ns_sbh[1];
 467         nilfs->ns_sbp[0] = nilfs->ns_sbp[1];
 468         nilfs->ns_sbh[1] = NULL;
 469         nilfs->ns_sbp[1] = NULL;
 470 }
 471
 472 void nilfs_swap_super_block(struct the_nilfs *nilfs)
 473 {
 474         struct buffer_head *tsbh = nilfs->ns_sbh[0];
 475         struct nilfs_super_block *tsbp = nilfs->ns_sbp[0];
 476
 477         nilfs->ns_sbh[0] = nilfs->ns_sbh[1];
 478         nilfs->ns_sbp[0] = nilfs->ns_sbp[1];
 479         nilfs->ns_sbh[1] = tsbh;
 480         nilfs->ns_sbp[1] = tsbp;
 481 }
 482
 483 static int nilfs_load_super_block(struct the_nilfs *nilfs,
 484                                   struct super_block *sb, int blocksize,
 485                                   struct nilfs_super_block **sbpp)
 486 {
 487         struct nilfs_super_block **sbp = nilfs->ns_sbp;
 488         struct buffer_head **sbh = nilfs->ns_sbh;
 489         u64 sb2off = NILFS_SB2_OFFSET_BYTES(nilfs->ns_bdev->bd_inode->i_size);
 490         int valid[2], swp = 0;
 491
 492         sbp[0] = nilfs_read_super_block(sb, NILFS_SB_OFFSET_BYTES, blocksize,
 493                                         &sbh[0]);
 494         sbp[1] = nilfs_read_super_block(sb, sb2off, blocksize, &sbh[1]);
 495
 496         if (!sbp[0]) {
 497                 if (!sbp[1]) {
 498                         printk(KERN_ERR "NILFS: unable to read superblock\n");
 499                         return -EIO;
 500                 }
 501                 printk(KERN_WARNING
 502                        "NILFS warning: unable to read primary superblock "
 503                        "(blocksize = %d)\n", blocksize);
 504         } else if (!sbp[1]) {
 505                 printk(KERN_WARNING
 506                        "NILFS warning: unable to read secondary superblock "
 507                        "(blocksize = %d)\n", blocksize);
 508         }
 509
 510         /*
 511          * Compare two super blocks and set 1 in swp if the secondary
 512          * super block is valid and newer.  Otherwise, set 0 in swp.
 513          */
 514         valid[0] = nilfs_valid_sb(sbp[0]);
 515         valid[1] = nilfs_valid_sb(sbp[1]);
 516         swp = valid[1] && (!valid[0] ||
 517                            le64_to_cpu(sbp[1]->s_last_cno) >
 518                            le64_to_cpu(sbp[0]->s_last_cno));
 519
 520         if (valid[swp] && nilfs_sb2_bad_offset(sbp[swp], sb2off)) {
 521                 brelse(sbh[1]);
 522                 sbh[1] = NULL;
 523                 sbp[1] = NULL;
 524                 valid[1] = 0;
 525                 swp = 0;
 526         }
 527         if (!valid[swp]) {
 528                 nilfs_release_super_block(nilfs);
 529                 printk(KERN_ERR "NILFS: Can't find nilfs on dev %s.\n",
 530                        sb->s_id);
 531                 return -EINVAL;
 532         }
 533
 534         if (!valid[!swp])
 535                 printk(KERN_WARNING "NILFS warning: broken superblock. "
 536                        "using spare superblock (blocksize = %d).\n", blocksize);
 537         if (swp)
 538                 nilfs_swap_super_block(nilfs);
 539
 540         nilfs->ns_sbwcount = 0;
 541         nilfs->ns_sbwtime = le64_to_cpu(sbp[0]->s_wtime);
 542         nilfs->ns_prot_seq = le64_to_cpu(sbp[valid[1] & !swp]->s_last_seq);
 543         *sbpp = sbp[0];
 544         return 0;
 545 }
 546
 547 /**
 548  * init_nilfs - initialize a NILFS instance.
 549  * @nilfs: the_nilfs structure
 550  * @sb: super block
 551  * @data: mount options
 552  *
 553  * init_nilfs() performs common initialization per block device (e.g.
 554  * reading the super block, getting disk layout information, initializing
 555  * shared fields in the_nilfs).
 556  *
 557  * Return Value: On success, 0 is returned. On error, a negative error
 558  * code is returned.
 559  */
 560 int init_nilfs(struct the_nilfs *nilfs, struct super_block *sb, char *data)
 561 {
 562         struct nilfs_super_block *sbp;
 563         int blocksize;
 564         int err;
 565
 566         down_write(&nilfs->ns_sem);
 567
 568         blocksize = sb_min_blocksize(sb, NILFS_MIN_BLOCK_SIZE);
 569         if (!blocksize) {
 570                 printk(KERN_ERR "NILFS: unable to set blocksize\n");
 571                 err = -EINVAL;
 572                 goto out;
 573         }
 574         err = nilfs_load_super_block(nilfs, sb, blocksize, &sbp);
 575         if (err)
 576                 goto out;
 577
 578         err = nilfs_store_magic_and_option(sb, sbp, data);
 579         if (err)
 580                 goto failed_sbh;
 581
 582         err = nilfs_check_feature_compatibility(sb, sbp);
 583         if (err)
 584                 goto failed_sbh;
 585
 586         blocksize = BLOCK_SIZE << le32_to_cpu(sbp->s_log_block_size);
 587         if (blocksize < NILFS_MIN_BLOCK_SIZE ||
 588             blocksize > NILFS_MAX_BLOCK_SIZE) {
 589                 printk(KERN_ERR "NILFS: couldn't mount because of unsupported "
 590                        "filesystem blocksize %d\n", blocksize);
 591                 err = -EINVAL;
 592                 goto failed_sbh;
 593         }
 594         if (sb->s_blocksize != blocksize) {
 595                 int hw_blocksize = bdev_logical_block_size(sb->s_bdev);
 596
 597                 if (blocksize < hw_blocksize) {
 598                         printk(KERN_ERR
 599                                "NILFS: blocksize %d too small for device "
 600                                "(sector-size = %d).\n",
 601                                blocksize, hw_blocksize);
 602                         err = -EINVAL;
 603                         goto failed_sbh;
 604                 }
 605                 nilfs_release_super_block(nilfs);
 606                 sb_set_blocksize(sb, blocksize);
 607
 608                 err = nilfs_load_super_block(nilfs, sb, blocksize, &sbp);
 609                 if (err)
 610                         goto out;
 611                         /* not failed_sbh; sbh is released automatically
 612                            when reloading fails. */
 613         }
 614         nilfs->ns_blocksize_bits = sb->s_blocksize_bits;
 615         nilfs->ns_blocksize = blocksize;
 616
 617         get_random_bytes(&nilfs->ns_next_generation,
 618                          sizeof(nilfs->ns_next_generation));
 619
 620         err = nilfs_store_disk_layout(nilfs, sbp);
 621         if (err)
 622                 goto failed_sbh;
 623
 624         sb->s_maxbytes = nilfs_max_size(sb->s_blocksize_bits);
 625
 626         nilfs->ns_mount_state = le16_to_cpu(sbp->s_state);
 627
 628         err = nilfs_store_log_cursor(nilfs, sbp);
 629         if (err)
 630                 goto failed_sbh;
 631
 632         set_nilfs_init(nilfs);
 633         err = 0;
 634  out:
 635         up_write(&nilfs->ns_sem);
 636         return err;
 637
 638  failed_sbh:
 639         nilfs_release_super_block(nilfs);
 640         goto out;
 641 }
 642
 643 int nilfs_discard_segments(struct the_nilfs *nilfs, __u64 *segnump,
 644                             size_t nsegs)
 645 {
 646         sector_t seg_start, seg_end;
 647         sector_t start = 0, nblocks = 0;
 648         unsigned int sects_per_block;
 649         __u64 *sn;
 650         int ret = 0;
 651
 652         sects_per_block = (1 << nilfs->ns_blocksize_bits) /
 653                 bdev_logical_block_size(nilfs->ns_bdev);
 654         for (sn = segnump; sn < segnump + nsegs; sn++) {
 655                 nilfs_get_segment_range(nilfs, *sn, &seg_start, &seg_end);
 656
 657                 if (!nblocks) {
 658                         start = seg_start;
 659                         nblocks = seg_end - seg_start + 1;
 660                 } else if (start + nblocks == seg_start) {
 661                         nblocks += seg_end - seg_start + 1;
 662                 } else {
 663                         ret = blkdev_issue_discard(nilfs->ns_bdev,
 664                                                    start * sects_per_block,
 665                                                    nblocks * sects_per_block,
 666                                                    GFP_NOFS, 0);
 667                         if (ret < 0)
 668                                 return ret;
 669                         nblocks = 0;
 670                 }
 671         }
 672         if (nblocks)
 673                 ret = blkdev_issue_discard(nilfs->ns_bdev,
 674                                            start * sects_per_block,
 675                                            nblocks * sects_per_block,
 676                                            GFP_NOFS, 0);
 677         return ret;
 678 }
 679
 680 int nilfs_count_free_blocks(struct the_nilfs *nilfs, sector_t *nblocks)
 681 {
 682         unsigned long ncleansegs;
 683
 684         down_read(&NILFS_MDT(nilfs->ns_dat)->mi_sem);
 685         ncleansegs = nilfs_sufile_get_ncleansegs(nilfs->ns_sufile);
 686         up_read(&NILFS_MDT(nilfs->ns_dat)->mi_sem);
 687         *nblocks = (sector_t)ncleansegs * nilfs->ns_blocks_per_segment;
 688         return 0;
 689 }
 690
 691 int nilfs_near_disk_full(struct the_nilfs *nilfs)
 692 {
 693         unsigned long ncleansegs, nincsegs;
 694
 695         ncleansegs = nilfs_sufile_get_ncleansegs(nilfs->ns_sufile);
 696         nincsegs = atomic_read(&nilfs->ns_ndirtyblks) /
 697                 nilfs->ns_blocks_per_segment + 1;
 698
 699         return ncleansegs <= nilfs->ns_nrsvsegs + nincsegs;
 700 }
 701
 702 struct nilfs_root *nilfs_lookup_root(struct the_nilfs *nilfs, __u64 cno)
 703 {
 704         struct rb_node *n;
 705         struct nilfs_root *root;
 706
 707         spin_lock(&nilfs->ns_cptree_lock);
 708         n = nilfs->ns_cptree.rb_node;
 709         while (n) {
 710                 root = rb_entry(n, struct nilfs_root, rb_node);
 711
 712                 if (cno < root->cno) {
 713                         n = n->rb_left;
 714                 } else if (cno > root->cno) {
 715                         n = n->rb_right;
 716                 } else {
 717                         atomic_inc(&root->count);
 718                         spin_unlock(&nilfs->ns_cptree_lock);
 719                         return root;
 720                 }
 721         }
 722         spin_unlock(&nilfs->ns_cptree_lock);
 723
 724         return NULL;
 725 }
 726
 727 struct nilfs_root *
 728 nilfs_find_or_create_root(struct the_nilfs *nilfs, __u64 cno)
 729 {
 730         struct rb_node **p, *parent;
 731         struct nilfs_root *root, *new;
 732
 733         root = nilfs_lookup_root(nilfs, cno);
 734         if (root)
 735                 return root;
 736
 737         new = kmalloc(sizeof(*root), GFP_KERNEL);
 738         if (!new)
 739                 return NULL;
 740
 741         spin_lock(&nilfs->ns_cptree_lock);
 742
 743         p = &nilfs->ns_cptree.rb_node;
 744         parent = NULL;
 745
 746         while (*p) {
 747                 parent = *p;
 748                 root = rb_entry(parent, struct nilfs_root, rb_node);
 749
 750                 if (cno < root->cno) {
 751                         p = &(*p)->rb_left;
 752                 } else if (cno > root->cno) {
 753                         p = &(*p)->rb_right;
 754                 } else {
 755                         atomic_inc(&root->count);
 756                         spin_unlock(&nilfs->ns_cptree_lock);
 757                         kfree(new);
 758                         return root;
 759                 }
 760         }
 761
 762         new->cno = cno;
 763         new->ifile = NULL;
 764         new->nilfs = nilfs;
 765         atomic_set(&new->count, 1);
 766         atomic_set(&new->inodes_count, 0);
 767         atomic_set(&new->blocks_count, 0);
 768
 769         rb_link_node(&new->rb_node, parent, p);
 770         rb_insert_color(&new->rb_node, &nilfs->ns_cptree);
 771
 772         spin_unlock(&nilfs->ns_cptree_lock);
 773
 774         return new;
 775 }
 776
 777 void nilfs_put_root(struct nilfs_root *root)
 778 {
 779         if (atomic_dec_and_test(&root->count)) {
 780                 struct the_nilfs *nilfs = root->nilfs;
 781
 782                 spin_lock(&nilfs->ns_cptree_lock);
 783                 rb_erase(&root->rb_node, &nilfs->ns_cptree);
 784                 spin_unlock(&nilfs->ns_cptree_lock);
 785                 if (root->ifile)
 786                         iput(root->ifile);
 787
 788                 kfree(root);
 789         }
 790 }