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  * Written by Ryusuke Konishi.
  17  *
  18  */
  19
  20 #include <linux/buffer_head.h>
  21 #include <linux/slab.h>
  22 #include <linux/blkdev.h>
  23 #include <linux/backing-dev.h>
  24 #include <linux/random.h>
  25 #include <linux/crc32.h>
  26 #include "nilfs.h"
  27 #include "segment.h"
  28 #include "alloc.h"
  29 #include "cpfile.h"
  30 #include "sufile.h"
  31 #include "dat.h"
  32 #include "segbuf.h"
  33
  34
  35 static int nilfs_valid_sb(struct nilfs_super_block *sbp);
  36
  37 void nilfs_set_last_segment(struct the_nilfs *nilfs,
  38                             sector_t start_blocknr, u64 seq, __u64 cno)
  39 {
  40         spin_lock(&nilfs->ns_last_segment_lock);
  41         nilfs->ns_last_pseg = start_blocknr;
  42         nilfs->ns_last_seq = seq;
  43         nilfs->ns_last_cno = cno;
  44
  45         if (!nilfs_sb_dirty(nilfs)) {
  46                 if (nilfs->ns_prev_seq == nilfs->ns_last_seq)
  47                         goto stay_cursor;
  48
  49                 set_nilfs_sb_dirty(nilfs);
  50         }
  51         nilfs->ns_prev_seq = nilfs->ns_last_seq;
  52
  53  stay_cursor:
  54         spin_unlock(&nilfs->ns_last_segment_lock);
  55 }
  56
  57 /**
  58  * alloc_nilfs - allocate a nilfs object
  59  * @sb: super block instance
  60  *
  61  * Return Value: On success, pointer to the_nilfs is returned.
  62  * On error, NULL is returned.
  63  */
  64 struct the_nilfs *alloc_nilfs(struct super_block *sb)
  65 {
  66         struct the_nilfs *nilfs;
  67
  68         nilfs = kzalloc(sizeof(*nilfs), GFP_KERNEL);
  69         if (!nilfs)
  70                 return NULL;
  71
  72         nilfs->ns_sb = sb;
  73         nilfs->ns_bdev = sb->s_bdev;
  74         atomic_set(&nilfs->ns_ndirtyblks, 0);
  75         init_rwsem(&nilfs->ns_sem);
  76         mutex_init(&nilfs->ns_snapshot_mount_mutex);
  77         INIT_LIST_HEAD(&nilfs->ns_dirty_files);
  78         INIT_LIST_HEAD(&nilfs->ns_gc_inodes);
  79         spin_lock_init(&nilfs->ns_inode_lock);
  80         spin_lock_init(&nilfs->ns_next_gen_lock);
  81         spin_lock_init(&nilfs->ns_last_segment_lock);
  82         nilfs->ns_cptree = RB_ROOT;
  83         spin_lock_init(&nilfs->ns_cptree_lock);
  84         init_rwsem(&nilfs->ns_segctor_sem);
  85         nilfs->ns_sb_update_freq = NILFS_SB_FREQ;
  86
  87         return nilfs;
  88 }
  89
  90 /**
  91  * destroy_nilfs - destroy nilfs object
  92  * @nilfs: nilfs object to be released
  93  */
  94 void destroy_nilfs(struct the_nilfs *nilfs)
  95 {
  96         might_sleep();
  97         if (nilfs_init(nilfs)) {
  98                 nilfs_sysfs_delete_device_group(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 int dat_entry_size, segment_usage_size, checkpoint_size;
 113         unsigned int 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                 nilfs_msg(nilfs->ns_sb, KERN_ERR,
 196                           "pointed segment number is out of range: segnum=%llu, nsegments=%lu",
 197                           (unsigned long long)nilfs->ns_segnum,
 198                           nilfs->ns_nsegments);
 199                 ret = -EINVAL;
 200         }
 201         return ret;
 202 }
 203
 204 /**
 205  * load_nilfs - load and recover the nilfs
 206  * @nilfs: the_nilfs structure to be released
 207  * @sb: super block isntance used to recover past segment
 208  *
 209  * load_nilfs() searches and load the latest super root,
 210  * attaches the last segment, and does recovery if needed.
 211  * The caller must call this exclusively for simultaneous mounts.
 212  */
 213 int load_nilfs(struct the_nilfs *nilfs, struct super_block *sb)
 214 {
 215         struct nilfs_recovery_info ri;
 216         unsigned int s_flags = sb->s_flags;
 217         int really_read_only = bdev_read_only(nilfs->ns_bdev);
 218         int valid_fs = nilfs_valid_fs(nilfs);
 219         int err;
 220
 221         if (!valid_fs) {
 222                 nilfs_msg(sb, KERN_WARNING, "mounting unchecked fs");
 223                 if (s_flags & MS_RDONLY) {
 224                         nilfs_msg(sb, KERN_INFO,
 225                                   "recovery required for readonly filesystem");
 226                         nilfs_msg(sb, KERN_INFO,
 227                                   "write access will be enabled during recovery");
 228                 }
 229         }
 230
 231         nilfs_init_recovery_info(&ri);
 232
 233         err = nilfs_search_super_root(nilfs, &ri);
 234         if (unlikely(err)) {
 235                 struct nilfs_super_block **sbp = nilfs->ns_sbp;
 236                 int blocksize;
 237
 238                 if (err != -EINVAL)
 239                         goto scan_error;
 240
 241                 if (!nilfs_valid_sb(sbp[1])) {
 242                         nilfs_msg(sb, KERN_WARNING,
 243                                   "unable to fall back to spare super block");
 244                         goto scan_error;
 245                 }
 246                 nilfs_msg(sb, KERN_INFO,
 247                           "trying rollback from an earlier position");
 248
 249                 /*
 250                  * restore super block with its spare and reconfigure
 251                  * relevant states of the nilfs object.
 252                  */
 253                 memcpy(sbp[0], sbp[1], nilfs->ns_sbsize);
 254                 nilfs->ns_crc_seed = le32_to_cpu(sbp[0]->s_crc_seed);
 255                 nilfs->ns_sbwtime = le64_to_cpu(sbp[0]->s_wtime);
 256
 257                 /* verify consistency between two super blocks */
 258                 blocksize = BLOCK_SIZE << le32_to_cpu(sbp[0]->s_log_block_size);
 259                 if (blocksize != nilfs->ns_blocksize) {
 260                         nilfs_msg(sb, KERN_WARNING,
 261                                   "blocksize differs between two super blocks (%d != %d)",
 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                 nilfs_msg(sb, KERN_ERR, "error %d while loading super root",
 282                           err);
 283                 goto failed;
 284         }
 285
 286         if (valid_fs)
 287                 goto skip_recovery;
 288
 289         if (s_flags & MS_RDONLY) {
 290                 __u64 features;
 291
 292                 if (nilfs_test_opt(nilfs, NORECOVERY)) {
 293                         nilfs_msg(sb, KERN_INFO,
 294                                   "norecovery option specified, skipping roll-forward recovery");
 295                         goto skip_recovery;
 296                 }
 297                 features = le64_to_cpu(nilfs->ns_sbp[0]->s_feature_compat_ro) &
 298                         ~NILFS_FEATURE_COMPAT_RO_SUPP;
 299                 if (features) {
 300                         nilfs_msg(sb, KERN_ERR,
 301                                   "couldn't proceed with recovery because of unsupported optional features (%llx)",
 302                                   (unsigned long long)features);
 303                         err = -EROFS;
 304                         goto failed_unload;
 305                 }
 306                 if (really_read_only) {
 307                         nilfs_msg(sb, KERN_ERR,
 308                                   "write access unavailable, cannot proceed");
 309                         err = -EROFS;
 310                         goto failed_unload;
 311                 }
 312                 sb->s_flags &= ~MS_RDONLY;
 313         } else if (nilfs_test_opt(nilfs, NORECOVERY)) {
 314                 nilfs_msg(sb, KERN_ERR,
 315                           "recovery cancelled because norecovery option was specified for a read/write mount");
 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                 nilfs_msg(sb, KERN_ERR,
 331                           "error %d updating super block. recovery unfinished.",
 332                           err);
 333                 goto failed_unload;
 334         }
 335         nilfs_msg(sb, KERN_INFO, "recovery complete");
 336
 337  skip_recovery:
 338         nilfs_clear_recovery_info(&ri);
 339         sb->s_flags = s_flags;
 340         return 0;
 341
 342  scan_error:
 343         nilfs_msg(sb, KERN_ERR, "error %d while searching super root", err);
 344         goto failed;
 345
 346  failed_unload:
 347         iput(nilfs->ns_cpfile);
 348         iput(nilfs->ns_sufile);
 349         iput(nilfs->ns_dat);
 350
 351  failed:
 352         nilfs_clear_recovery_info(&ri);
 353         sb->s_flags = s_flags;
 354         return err;
 355 }
 356
 357 static unsigned long long nilfs_max_size(unsigned int blkbits)
 358 {
 359         unsigned int max_bits;
 360         unsigned long long res = MAX_LFS_FILESIZE; /* page cache limit */
 361
 362         max_bits = blkbits + NILFS_BMAP_KEY_BIT; /* bmap size limit */
 363         if (max_bits < 64)
 364                 res = min_t(unsigned long long, res, (1ULL << max_bits) - 1);
 365         return res;
 366 }
 367
 368 /**
 369  * nilfs_nrsvsegs - calculate the number of reserved segments
 370  * @nilfs: nilfs object
 371  * @nsegs: total number of segments
 372  */
 373 unsigned long nilfs_nrsvsegs(struct the_nilfs *nilfs, unsigned long nsegs)
 374 {
 375         return max_t(unsigned long, NILFS_MIN_NRSVSEGS,
 376                      DIV_ROUND_UP(nsegs * nilfs->ns_r_segments_percentage,
 377                                   100));
 378 }
 379
 380 void nilfs_set_nsegments(struct the_nilfs *nilfs, unsigned long nsegs)
 381 {
 382         nilfs->ns_nsegments = nsegs;
 383         nilfs->ns_nrsvsegs = nilfs_nrsvsegs(nilfs, nsegs);
 384 }
 385
 386 static int nilfs_store_disk_layout(struct the_nilfs *nilfs,
 387                                    struct nilfs_super_block *sbp)
 388 {
 389         if (le32_to_cpu(sbp->s_rev_level) < NILFS_MIN_SUPP_REV) {
 390                 nilfs_msg(nilfs->ns_sb, KERN_ERR,
 391                           "unsupported revision (superblock rev.=%d.%d, current rev.=%d.%d). Please check the version of mkfs.nilfs(2).",
 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         if (nilfs->ns_inode_size > nilfs->ns_blocksize) {
 403                 nilfs_msg(nilfs->ns_sb, KERN_ERR,
 404                           "too large inode size: %d bytes",
 405                           nilfs->ns_inode_size);
 406                 return -EINVAL;
 407         } else if (nilfs->ns_inode_size < NILFS_MIN_INODE_SIZE) {
 408                 nilfs_msg(nilfs->ns_sb, KERN_ERR,
 409                           "too small inode size: %d bytes",
 410                           nilfs->ns_inode_size);
 411                 return -EINVAL;
 412         }
 413
 414         nilfs->ns_first_ino = le32_to_cpu(sbp->s_first_ino);
 415
 416         nilfs->ns_blocks_per_segment = le32_to_cpu(sbp->s_blocks_per_segment);
 417         if (nilfs->ns_blocks_per_segment < NILFS_SEG_MIN_BLOCKS) {
 418                 nilfs_msg(nilfs->ns_sb, KERN_ERR,
 419                           "too short segment: %lu blocks",
 420                           nilfs->ns_blocks_per_segment);
 421                 return -EINVAL;
 422         }
 423
 424         nilfs->ns_first_data_block = le64_to_cpu(sbp->s_first_data_block);
 425         nilfs->ns_r_segments_percentage =
 426                 le32_to_cpu(sbp->s_r_segments_percentage);
 427         if (nilfs->ns_r_segments_percentage < 1 ||
 428             nilfs->ns_r_segments_percentage > 99) {
 429                 nilfs_msg(nilfs->ns_sb, KERN_ERR,
 430                           "invalid reserved segments percentage: %lu",
 431                           nilfs->ns_r_segments_percentage);
 432                 return -EINVAL;
 433         }
 434
 435         nilfs_set_nsegments(nilfs, le64_to_cpu(sbp->s_nsegments));
 436         nilfs->ns_crc_seed = le32_to_cpu(sbp->s_crc_seed);
 437         return 0;
 438 }
 439
 440 static int nilfs_valid_sb(struct nilfs_super_block *sbp)
 441 {
 442         static unsigned char sum[4];
 443         const int sumoff = offsetof(struct nilfs_super_block, s_sum);
 444         size_t bytes;
 445         u32 crc;
 446
 447         if (!sbp || le16_to_cpu(sbp->s_magic) != NILFS_SUPER_MAGIC)
 448                 return 0;
 449         bytes = le16_to_cpu(sbp->s_bytes);
 450         if (bytes < sumoff + 4 || bytes > BLOCK_SIZE)
 451                 return 0;
 452         crc = crc32_le(le32_to_cpu(sbp->s_crc_seed), (unsigned char *)sbp,
 453                        sumoff);
 454         crc = crc32_le(crc, sum, 4);
 455         crc = crc32_le(crc, (unsigned char *)sbp + sumoff + 4,
 456                        bytes - sumoff - 4);
 457         return crc == le32_to_cpu(sbp->s_sum);
 458 }
 459
 460 static int nilfs_sb2_bad_offset(struct nilfs_super_block *sbp, u64 offset)
 461 {
 462         return offset < ((le64_to_cpu(sbp->s_nsegments) *
 463                           le32_to_cpu(sbp->s_blocks_per_segment)) <<
 464                          (le32_to_cpu(sbp->s_log_block_size) + 10));
 465 }
 466
 467 static void nilfs_release_super_block(struct the_nilfs *nilfs)
 468 {
 469         int i;
 470
 471         for (i = 0; i < 2; i++) {
 472                 if (nilfs->ns_sbp[i]) {
 473                         brelse(nilfs->ns_sbh[i]);
 474                         nilfs->ns_sbh[i] = NULL;
 475                         nilfs->ns_sbp[i] = NULL;
 476                 }
 477         }
 478 }
 479
 480 void nilfs_fall_back_super_block(struct the_nilfs *nilfs)
 481 {
 482         brelse(nilfs->ns_sbh[0]);
 483         nilfs->ns_sbh[0] = nilfs->ns_sbh[1];
 484         nilfs->ns_sbp[0] = nilfs->ns_sbp[1];
 485         nilfs->ns_sbh[1] = NULL;
 486         nilfs->ns_sbp[1] = NULL;
 487 }
 488
 489 void nilfs_swap_super_block(struct the_nilfs *nilfs)
 490 {
 491         struct buffer_head *tsbh = nilfs->ns_sbh[0];
 492         struct nilfs_super_block *tsbp = nilfs->ns_sbp[0];
 493
 494         nilfs->ns_sbh[0] = nilfs->ns_sbh[1];
 495         nilfs->ns_sbp[0] = nilfs->ns_sbp[1];
 496         nilfs->ns_sbh[1] = tsbh;
 497         nilfs->ns_sbp[1] = tsbp;
 498 }
 499
 500 static int nilfs_load_super_block(struct the_nilfs *nilfs,
 501                                   struct super_block *sb, int blocksize,
 502                                   struct nilfs_super_block **sbpp)
 503 {
 504         struct nilfs_super_block **sbp = nilfs->ns_sbp;
 505         struct buffer_head **sbh = nilfs->ns_sbh;
 506         u64 sb2off = NILFS_SB2_OFFSET_BYTES(nilfs->ns_bdev->bd_inode->i_size);
 507         int valid[2], swp = 0;
 508
 509         sbp[0] = nilfs_read_super_block(sb, NILFS_SB_OFFSET_BYTES, blocksize,
 510                                         &sbh[0]);
 511         sbp[1] = nilfs_read_super_block(sb, sb2off, blocksize, &sbh[1]);
 512
 513         if (!sbp[0]) {
 514                 if (!sbp[1]) {
 515                         nilfs_msg(sb, KERN_ERR, "unable to read superblock");
 516                         return -EIO;
 517                 }
 518                 nilfs_msg(sb, KERN_WARNING,
 519                           "unable to read primary superblock (blocksize = %d)",
 520                           blocksize);
 521         } else if (!sbp[1]) {
 522                 nilfs_msg(sb, KERN_WARNING,
 523                           "unable to read secondary superblock (blocksize = %d)",
 524                           blocksize);
 525         }
 526
 527         /*
 528          * Compare two super blocks and set 1 in swp if the secondary
 529          * super block is valid and newer.  Otherwise, set 0 in swp.
 530          */
 531         valid[0] = nilfs_valid_sb(sbp[0]);
 532         valid[1] = nilfs_valid_sb(sbp[1]);
 533         swp = valid[1] && (!valid[0] ||
 534                            le64_to_cpu(sbp[1]->s_last_cno) >
 535                            le64_to_cpu(sbp[0]->s_last_cno));
 536
 537         if (valid[swp] && nilfs_sb2_bad_offset(sbp[swp], sb2off)) {
 538                 brelse(sbh[1]);
 539                 sbh[1] = NULL;
 540                 sbp[1] = NULL;
 541                 valid[1] = 0;
 542                 swp = 0;
 543         }
 544         if (!valid[swp]) {
 545                 nilfs_release_super_block(nilfs);
 546                 nilfs_msg(sb, KERN_ERR, "couldn't find nilfs on the device");
 547                 return -EINVAL;
 548         }
 549
 550         if (!valid[!swp])
 551                 nilfs_msg(sb, KERN_WARNING,
 552                           "broken superblock, retrying with spare superblock (blocksize = %d)",
 553                           blocksize);
 554         if (swp)
 555                 nilfs_swap_super_block(nilfs);
 556
 557         nilfs->ns_sbwcount = 0;
 558         nilfs->ns_sbwtime = le64_to_cpu(sbp[0]->s_wtime);
 559         nilfs->ns_prot_seq = le64_to_cpu(sbp[valid[1] & !swp]->s_last_seq);
 560         *sbpp = sbp[0];
 561         return 0;
 562 }
 563
 564 /**
 565  * init_nilfs - initialize a NILFS instance.
 566  * @nilfs: the_nilfs structure
 567  * @sb: super block
 568  * @data: mount options
 569  *
 570  * init_nilfs() performs common initialization per block device (e.g.
 571  * reading the super block, getting disk layout information, initializing
 572  * shared fields in the_nilfs).
 573  *
 574  * Return Value: On success, 0 is returned. On error, a negative error
 575  * code is returned.
 576  */
 577 int init_nilfs(struct the_nilfs *nilfs, struct super_block *sb, char *data)
 578 {
 579         struct nilfs_super_block *sbp;
 580         int blocksize;
 581         int err;
 582
 583         down_write(&nilfs->ns_sem);
 584
 585         blocksize = sb_min_blocksize(sb, NILFS_MIN_BLOCK_SIZE);
 586         if (!blocksize) {
 587                 nilfs_msg(sb, KERN_ERR, "unable to set blocksize");
 588                 err = -EINVAL;
 589                 goto out;
 590         }
 591         err = nilfs_load_super_block(nilfs, sb, blocksize, &sbp);
 592         if (err)
 593                 goto out;
 594
 595         err = nilfs_store_magic_and_option(sb, sbp, data);
 596         if (err)
 597                 goto failed_sbh;
 598
 599         err = nilfs_check_feature_compatibility(sb, sbp);
 600         if (err)
 601                 goto failed_sbh;
 602
 603         blocksize = BLOCK_SIZE << le32_to_cpu(sbp->s_log_block_size);
 604         if (blocksize < NILFS_MIN_BLOCK_SIZE ||
 605             blocksize > NILFS_MAX_BLOCK_SIZE) {
 606                 nilfs_msg(sb, KERN_ERR,
 607                           "couldn't mount because of unsupported filesystem blocksize %d",
 608                           blocksize);
 609                 err = -EINVAL;
 610                 goto failed_sbh;
 611         }
 612         if (sb->s_blocksize != blocksize) {
 613                 int hw_blocksize = bdev_logical_block_size(sb->s_bdev);
 614
 615                 if (blocksize < hw_blocksize) {
 616                         nilfs_msg(sb, KERN_ERR,
 617                                   "blocksize %d too small for device (sector-size = %d)",
 618                                   blocksize, hw_blocksize);
 619                         err = -EINVAL;
 620                         goto failed_sbh;
 621                 }
 622                 nilfs_release_super_block(nilfs);
 623                 sb_set_blocksize(sb, blocksize);
 624
 625                 err = nilfs_load_super_block(nilfs, sb, blocksize, &sbp);
 626                 if (err)
 627                         goto out;
 628                         /*
 629                          * Not to failed_sbh; sbh is released automatically
 630                          * when reloading fails.
 631                          */
 632         }
 633         nilfs->ns_blocksize_bits = sb->s_blocksize_bits;
 634         nilfs->ns_blocksize = blocksize;
 635
 636         get_random_bytes(&nilfs->ns_next_generation,
 637                          sizeof(nilfs->ns_next_generation));
 638
 639         err = nilfs_store_disk_layout(nilfs, sbp);
 640         if (err)
 641                 goto failed_sbh;
 642
 643         sb->s_maxbytes = nilfs_max_size(sb->s_blocksize_bits);
 644
 645         nilfs->ns_mount_state = le16_to_cpu(sbp->s_state);
 646
 647         err = nilfs_store_log_cursor(nilfs, sbp);
 648         if (err)
 649                 goto failed_sbh;
 650
 651         err = nilfs_sysfs_create_device_group(sb);
 652         if (err)
 653                 goto failed_sbh;
 654
 655         set_nilfs_init(nilfs);
 656         err = 0;
 657  out:
 658         up_write(&nilfs->ns_sem);
 659         return err;
 660
 661  failed_sbh:
 662         nilfs_release_super_block(nilfs);
 663         goto out;
 664 }
 665
 666 int nilfs_discard_segments(struct the_nilfs *nilfs, __u64 *segnump,
 667                             size_t nsegs)
 668 {
 669         sector_t seg_start, seg_end;
 670         sector_t start = 0, nblocks = 0;
 671         unsigned int sects_per_block;
 672         __u64 *sn;
 673         int ret = 0;
 674
 675         sects_per_block = (1 << nilfs->ns_blocksize_bits) /
 676                 bdev_logical_block_size(nilfs->ns_bdev);
 677         for (sn = segnump; sn < segnump + nsegs; sn++) {
 678                 nilfs_get_segment_range(nilfs, *sn, &seg_start, &seg_end);
 679
 680                 if (!nblocks) {
 681                         start = seg_start;
 682                         nblocks = seg_end - seg_start + 1;
 683                 } else if (start + nblocks == seg_start) {
 684                         nblocks += seg_end - seg_start + 1;
 685                 } else {
 686                         ret = blkdev_issue_discard(nilfs->ns_bdev,
 687                                                    start * sects_per_block,
 688                                                    nblocks * sects_per_block,
 689                                                    GFP_NOFS, 0);
 690                         if (ret < 0)
 691                                 return ret;
 692                         nblocks = 0;
 693                 }
 694         }
 695         if (nblocks)
 696                 ret = blkdev_issue_discard(nilfs->ns_bdev,
 697                                            start * sects_per_block,
 698                                            nblocks * sects_per_block,
 699                                            GFP_NOFS, 0);
 700         return ret;
 701 }
 702
 703 int nilfs_count_free_blocks(struct the_nilfs *nilfs, sector_t *nblocks)
 704 {
 705         unsigned long ncleansegs;
 706
 707         down_read(&NILFS_MDT(nilfs->ns_dat)->mi_sem);
 708         ncleansegs = nilfs_sufile_get_ncleansegs(nilfs->ns_sufile);
 709         up_read(&NILFS_MDT(nilfs->ns_dat)->mi_sem);
 710         *nblocks = (sector_t)ncleansegs * nilfs->ns_blocks_per_segment;
 711         return 0;
 712 }
 713
 714 int nilfs_near_disk_full(struct the_nilfs *nilfs)
 715 {
 716         unsigned long ncleansegs, nincsegs;
 717
 718         ncleansegs = nilfs_sufile_get_ncleansegs(nilfs->ns_sufile);
 719         nincsegs = atomic_read(&nilfs->ns_ndirtyblks) /
 720                 nilfs->ns_blocks_per_segment + 1;
 721
 722         return ncleansegs <= nilfs->ns_nrsvsegs + nincsegs;
 723 }
 724
 725 struct nilfs_root *nilfs_lookup_root(struct the_nilfs *nilfs, __u64 cno)
 726 {
 727         struct rb_node *n;
 728         struct nilfs_root *root;
 729
 730         spin_lock(&nilfs->ns_cptree_lock);
 731         n = nilfs->ns_cptree.rb_node;
 732         while (n) {
 733                 root = rb_entry(n, struct nilfs_root, rb_node);
 734
 735                 if (cno < root->cno) {
 736                         n = n->rb_left;
 737                 } else if (cno > root->cno) {
 738                         n = n->rb_right;
 739                 } else {
 740                         atomic_inc(&root->count);
 741                         spin_unlock(&nilfs->ns_cptree_lock);
 742                         return root;
 743                 }
 744         }
 745         spin_unlock(&nilfs->ns_cptree_lock);
 746
 747         return NULL;
 748 }
 749
 750 struct nilfs_root *
 751 nilfs_find_or_create_root(struct the_nilfs *nilfs, __u64 cno)
 752 {
 753         struct rb_node **p, *parent;
 754         struct nilfs_root *root, *new;
 755         int err;
 756
 757         root = nilfs_lookup_root(nilfs, cno);
 758         if (root)
 759                 return root;
 760
 761         new = kzalloc(sizeof(*root), GFP_KERNEL);
 762         if (!new)
 763                 return NULL;
 764
 765         spin_lock(&nilfs->ns_cptree_lock);
 766
 767         p = &nilfs->ns_cptree.rb_node;
 768         parent = NULL;
 769
 770         while (*p) {
 771                 parent = *p;
 772                 root = rb_entry(parent, struct nilfs_root, rb_node);
 773
 774                 if (cno < root->cno) {
 775                         p = &(*p)->rb_left;
 776                 } else if (cno > root->cno) {
 777                         p = &(*p)->rb_right;
 778                 } else {
 779                         atomic_inc(&root->count);
 780                         spin_unlock(&nilfs->ns_cptree_lock);
 781                         kfree(new);
 782                         return root;
 783                 }
 784         }
 785
 786         new->cno = cno;
 787         new->ifile = NULL;
 788         new->nilfs = nilfs;
 789         atomic_set(&new->count, 1);
 790         atomic64_set(&new->inodes_count, 0);
 791         atomic64_set(&new->blocks_count, 0);
 792
 793         rb_link_node(&new->rb_node, parent, p);
 794         rb_insert_color(&new->rb_node, &nilfs->ns_cptree);
 795
 796         spin_unlock(&nilfs->ns_cptree_lock);
 797
 798         err = nilfs_sysfs_create_snapshot_group(new);
 799         if (err) {
 800                 kfree(new);
 801                 new = NULL;
 802         }
 803
 804         return new;
 805 }
 806
 807 void nilfs_put_root(struct nilfs_root *root)
 808 {
 809         if (atomic_dec_and_test(&root->count)) {
 810                 struct the_nilfs *nilfs = root->nilfs;
 811
 812                 nilfs_sysfs_delete_snapshot_group(root);
 813
 814                 spin_lock(&nilfs->ns_cptree_lock);
 815                 rb_erase(&root->rb_node, &nilfs->ns_cptree);
 816                 spin_unlock(&nilfs->ns_cptree_lock);
 817                 iput(root->ifile);
 818
 819                 kfree(root);
 820         }
 821 }