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