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