fs/nilfs2/recovery.c

   1 /*
   2  * recovery.c - NILFS recovery logic
   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 #include <linux/buffer_head.h>
  24 #include <linux/blkdev.h>
  25 #include <linux/swap.h>
  26 #include <linux/slab.h>
  27 #include <linux/crc32.h>
  28 #include "nilfs.h"
  29 #include "segment.h"
  30 #include "sufile.h"
  31 #include "page.h"
  32 #include "segbuf.h"
  33
  34 /*
  35  * Segment check result
  36  */
  37 enum {
  38         NILFS_SEG_VALID,
  39         NILFS_SEG_NO_SUPER_ROOT,
  40         NILFS_SEG_FAIL_IO,
  41         NILFS_SEG_FAIL_MAGIC,
  42         NILFS_SEG_FAIL_SEQ,
  43         NILFS_SEG_FAIL_CHECKSUM_SUPER_ROOT,
  44         NILFS_SEG_FAIL_CHECKSUM_FULL,
  45         NILFS_SEG_FAIL_CONSISTENCY,
  46 };
  47
  48 /* work structure for recovery */
  49 struct nilfs_recovery_block {
  50         ino_t ino;              /* Inode number of the file that this block
  51                                    belongs to */
  52         sector_t blocknr;       /* block number */
  53         __u64 vblocknr;         /* virtual block number */
  54         unsigned long blkoff;   /* File offset of the data block (per block) */
  55         struct list_head list;
  56 };
  57
  58
  59 static int nilfs_warn_segment_error(int err)
  60 {
  61         switch (err) {
  62         case NILFS_SEG_FAIL_IO:
  63                 printk(KERN_WARNING
  64                        "NILFS warning: I/O error on loading last segment\n");
  65                 return -EIO;
  66         case NILFS_SEG_FAIL_MAGIC:
  67                 printk(KERN_WARNING
  68                        "NILFS warning: Segment magic number invalid\n");
  69                 break;
  70         case NILFS_SEG_FAIL_SEQ:
  71                 printk(KERN_WARNING
  72                        "NILFS warning: Sequence number mismatch\n");
  73                 break;
  74         case NILFS_SEG_FAIL_CHECKSUM_SUPER_ROOT:
  75                 printk(KERN_WARNING
  76                        "NILFS warning: Checksum error in super root\n");
  77                 break;
  78         case NILFS_SEG_FAIL_CHECKSUM_FULL:
  79                 printk(KERN_WARNING
  80                        "NILFS warning: Checksum error in segment payload\n");
  81                 break;
  82         case NILFS_SEG_FAIL_CONSISTENCY:
  83                 printk(KERN_WARNING
  84                        "NILFS warning: Inconsistent segment\n");
  85                 break;
  86         case NILFS_SEG_NO_SUPER_ROOT:
  87                 printk(KERN_WARNING
  88                        "NILFS warning: No super root in the last segment\n");
  89                 break;
  90         }
  91         return -EINVAL;
  92 }
  93
  94 /**
  95  * nilfs_compute_checksum - compute checksum of blocks continuously
  96  * @nilfs: nilfs object
  97  * @bhs: buffer head of start block
  98  * @sum: place to store result
  99  * @offset: offset bytes in the first block
 100  * @check_bytes: number of bytes to be checked
 101  * @start: DBN of start block
 102  * @nblock: number of blocks to be checked
 103  */
 104 static int nilfs_compute_checksum(struct the_nilfs *nilfs,
 105                                   struct buffer_head *bhs, u32 *sum,
 106                                   unsigned long offset, u64 check_bytes,
 107                                   sector_t start, unsigned long nblock)
 108 {
 109         unsigned int blocksize = nilfs->ns_blocksize;
 110         unsigned long size;
 111         u32 crc;
 112
 113         BUG_ON(offset >= blocksize);
 114         check_bytes -= offset;
 115         size = min_t(u64, check_bytes, blocksize - offset);
 116         crc = crc32_le(nilfs->ns_crc_seed,
 117                        (unsigned char *)bhs->b_data + offset, size);
 118         if (--nblock > 0) {
 119                 do {
 120                         struct buffer_head *bh;
 121
 122                         bh = __bread(nilfs->ns_bdev, ++start, blocksize);
 123                         if (!bh)
 124                                 return -EIO;
 125                         check_bytes -= size;
 126                         size = min_t(u64, check_bytes, blocksize);
 127                         crc = crc32_le(crc, bh->b_data, size);
 128                         brelse(bh);
 129                 } while (--nblock > 0);
 130         }
 131         *sum = crc;
 132         return 0;
 133 }
 134
 135 /**
 136  * nilfs_read_super_root_block - read super root block
 137  * @nilfs: nilfs object
 138  * @sr_block: disk block number of the super root block
 139  * @pbh: address of a buffer_head pointer to return super root buffer
 140  * @check: CRC check flag
 141  */
 142 int nilfs_read_super_root_block(struct the_nilfs *nilfs, sector_t sr_block,
 143                                 struct buffer_head **pbh, int check)
 144 {
 145         struct buffer_head *bh_sr;
 146         struct nilfs_super_root *sr;
 147         u32 crc;
 148         int ret;
 149
 150         *pbh = NULL;
 151         bh_sr = __bread(nilfs->ns_bdev, sr_block, nilfs->ns_blocksize);
 152         if (unlikely(!bh_sr)) {
 153                 ret = NILFS_SEG_FAIL_IO;
 154                 goto failed;
 155         }
 156
 157         sr = (struct nilfs_super_root *)bh_sr->b_data;
 158         if (check) {
 159                 unsigned bytes = le16_to_cpu(sr->sr_bytes);
 160
 161                 if (bytes == 0 || bytes > nilfs->ns_blocksize) {
 162                         ret = NILFS_SEG_FAIL_CHECKSUM_SUPER_ROOT;
 163                         goto failed_bh;
 164                 }
 165                 if (nilfs_compute_checksum(
 166                             nilfs, bh_sr, &crc, sizeof(sr->sr_sum), bytes,
 167                             sr_block, 1)) {
 168                         ret = NILFS_SEG_FAIL_IO;
 169                         goto failed_bh;
 170                 }
 171                 if (crc != le32_to_cpu(sr->sr_sum)) {
 172                         ret = NILFS_SEG_FAIL_CHECKSUM_SUPER_ROOT;
 173                         goto failed_bh;
 174                 }
 175         }
 176         *pbh = bh_sr;
 177         return 0;
 178
 179  failed_bh:
 180         brelse(bh_sr);
 181
 182  failed:
 183         return nilfs_warn_segment_error(ret);
 184 }
 185
 186 /**
 187  * nilfs_read_log_header - read summary header of the specified log
 188  * @nilfs: nilfs object
 189  * @start_blocknr: start block number of the log
 190  * @sum: pointer to return segment summary structure
 191  */
 192 static struct buffer_head *
 193 nilfs_read_log_header(struct the_nilfs *nilfs, sector_t start_blocknr,
 194                       struct nilfs_segment_summary **sum)
 195 {
 196         struct buffer_head *bh_sum;
 197
 198         bh_sum = __bread(nilfs->ns_bdev, start_blocknr, nilfs->ns_blocksize);
 199         if (bh_sum)
 200                 *sum = (struct nilfs_segment_summary *)bh_sum->b_data;
 201         return bh_sum;
 202 }
 203
 204 /**
 205  * nilfs_validate_log - verify consistency of log
 206  * @nilfs: nilfs object
 207  * @seg_seq: sequence number of segment
 208  * @bh_sum: buffer head of summary block
 209  * @sum: segment summary struct
 210  */
 211 static int nilfs_validate_log(struct the_nilfs *nilfs, u64 seg_seq,
 212                               struct buffer_head *bh_sum,
 213                               struct nilfs_segment_summary *sum)
 214 {
 215         unsigned long nblock;
 216         u32 crc;
 217         int ret;
 218
 219         ret = NILFS_SEG_FAIL_MAGIC;
 220         if (le32_to_cpu(sum->ss_magic) != NILFS_SEGSUM_MAGIC)
 221                 goto out;
 222
 223         ret = NILFS_SEG_FAIL_SEQ;
 224         if (le64_to_cpu(sum->ss_seq) != seg_seq)
 225                 goto out;
 226
 227         nblock = le32_to_cpu(sum->ss_nblocks);
 228         ret = NILFS_SEG_FAIL_CONSISTENCY;
 229         if (unlikely(nblock == 0 || nblock > nilfs->ns_blocks_per_segment))
 230                 /* This limits the number of blocks read in the CRC check */
 231                 goto out;
 232
 233         ret = NILFS_SEG_FAIL_IO;
 234         if (nilfs_compute_checksum(nilfs, bh_sum, &crc, sizeof(sum->ss_datasum),
 235                                    ((u64)nblock << nilfs->ns_blocksize_bits),
 236                                    bh_sum->b_blocknr, nblock))
 237                 goto out;
 238
 239         ret = NILFS_SEG_FAIL_CHECKSUM_FULL;
 240         if (crc != le32_to_cpu(sum->ss_datasum))
 241                 goto out;
 242         ret = 0;
 243 out:
 244         return ret;
 245 }
 246
 247 /**
 248  * nilfs_read_summary_info - read an item on summary blocks of a log
 249  * @nilfs: nilfs object
 250  * @pbh: the current buffer head on summary blocks [in, out]
 251  * @offset: the current byte offset on summary blocks [in, out]
 252  * @bytes: byte size of the item to be read
 253  */
 254 static void *nilfs_read_summary_info(struct the_nilfs *nilfs,
 255                                      struct buffer_head **pbh,
 256                                      unsigned int *offset, unsigned int bytes)
 257 {
 258         void *ptr;
 259         sector_t blocknr;
 260
 261         BUG_ON((*pbh)->b_size < *offset);
 262         if (bytes > (*pbh)->b_size - *offset) {
 263                 blocknr = (*pbh)->b_blocknr;
 264                 brelse(*pbh);
 265                 *pbh = __bread(nilfs->ns_bdev, blocknr + 1,
 266                                nilfs->ns_blocksize);
 267                 if (unlikely(!*pbh))
 268                         return NULL;
 269                 *offset = 0;
 270         }
 271         ptr = (*pbh)->b_data + *offset;
 272         *offset += bytes;
 273         return ptr;
 274 }
 275
 276 /**
 277  * nilfs_skip_summary_info - skip items on summary blocks of a log
 278  * @nilfs: nilfs object
 279  * @pbh: the current buffer head on summary blocks [in, out]
 280  * @offset: the current byte offset on summary blocks [in, out]
 281  * @bytes: byte size of the item to be skipped
 282  * @count: number of items to be skipped
 283  */
 284 static void nilfs_skip_summary_info(struct the_nilfs *nilfs,
 285                                     struct buffer_head **pbh,
 286                                     unsigned int *offset, unsigned int bytes,
 287                                     unsigned long count)
 288 {
 289         unsigned int rest_item_in_current_block
 290                 = ((*pbh)->b_size - *offset) / bytes;
 291
 292         if (count <= rest_item_in_current_block) {
 293                 *offset += bytes * count;
 294         } else {
 295                 sector_t blocknr = (*pbh)->b_blocknr;
 296                 unsigned int nitem_per_block = (*pbh)->b_size / bytes;
 297                 unsigned int bcnt;
 298
 299                 count -= rest_item_in_current_block;
 300                 bcnt = DIV_ROUND_UP(count, nitem_per_block);
 301                 *offset = bytes * (count - (bcnt - 1) * nitem_per_block);
 302
 303                 brelse(*pbh);
 304                 *pbh = __bread(nilfs->ns_bdev, blocknr + bcnt,
 305                                nilfs->ns_blocksize);
 306         }
 307 }
 308
 309 /**
 310  * nilfs_scan_dsync_log - get block information of a log written for data sync
 311  * @nilfs: nilfs object
 312  * @start_blocknr: start block number of the log
 313  * @sum: log summary information
 314  * @head: list head to add nilfs_recovery_block struct
 315  */
 316 static int nilfs_scan_dsync_log(struct the_nilfs *nilfs, sector_t start_blocknr,
 317                                 struct nilfs_segment_summary *sum,
 318                                 struct list_head *head)
 319 {
 320         struct buffer_head *bh;
 321         unsigned int offset;
 322         u32 nfinfo, sumbytes;
 323         sector_t blocknr;
 324         ino_t ino;
 325         int err = -EIO;
 326
 327         nfinfo = le32_to_cpu(sum->ss_nfinfo);
 328         if (!nfinfo)
 329                 return 0;
 330
 331         sumbytes = le32_to_cpu(sum->ss_sumbytes);
 332         blocknr = start_blocknr + DIV_ROUND_UP(sumbytes, nilfs->ns_blocksize);
 333         bh = __bread(nilfs->ns_bdev, start_blocknr, nilfs->ns_blocksize);
 334         if (unlikely(!bh))
 335                 goto out;
 336
 337         offset = le16_to_cpu(sum->ss_bytes);
 338         for (;;) {
 339                 unsigned long nblocks, ndatablk, nnodeblk;
 340                 struct nilfs_finfo *finfo;
 341
 342                 finfo = nilfs_read_summary_info(nilfs, &bh, &offset,
 343                                                 sizeof(*finfo));
 344                 if (unlikely(!finfo))
 345                         goto out;
 346
 347                 ino = le64_to_cpu(finfo->fi_ino);
 348                 nblocks = le32_to_cpu(finfo->fi_nblocks);
 349                 ndatablk = le32_to_cpu(finfo->fi_ndatablk);
 350                 nnodeblk = nblocks - ndatablk;
 351
 352                 while (ndatablk-- > 0) {
 353                         struct nilfs_recovery_block *rb;
 354                         struct nilfs_binfo_v *binfo;
 355
 356                         binfo = nilfs_read_summary_info(nilfs, &bh, &offset,
 357                                                         sizeof(*binfo));
 358                         if (unlikely(!binfo))
 359                                 goto out;
 360
 361                         rb = kmalloc(sizeof(*rb), GFP_NOFS);
 362                         if (unlikely(!rb)) {
 363                                 err = -ENOMEM;
 364                                 goto out;
 365                         }
 366                         rb->ino = ino;
 367                         rb->blocknr = blocknr++;
 368                         rb->vblocknr = le64_to_cpu(binfo->bi_vblocknr);
 369                         rb->blkoff = le64_to_cpu(binfo->bi_blkoff);
 370                         /* INIT_LIST_HEAD(&rb->list); */
 371                         list_add_tail(&rb->list, head);
 372                 }
 373                 if (--nfinfo == 0)
 374                         break;
 375                 blocknr += nnodeblk; /* always 0 for data sync logs */
 376                 nilfs_skip_summary_info(nilfs, &bh, &offset, sizeof(__le64),
 377                                         nnodeblk);
 378                 if (unlikely(!bh))
 379                         goto out;
 380         }
 381         err = 0;
 382  out:
 383         brelse(bh);   /* brelse(NULL) is just ignored */
 384         return err;
 385 }
 386
 387 static void dispose_recovery_list(struct list_head *head)
 388 {
 389         while (!list_empty(head)) {
 390                 struct nilfs_recovery_block *rb
 391                         = list_entry(head->next,
 392                                      struct nilfs_recovery_block, list);
 393                 list_del(&rb->list);
 394                 kfree(rb);
 395         }
 396 }
 397
 398 struct nilfs_segment_entry {
 399         struct list_head        list;
 400         __u64                   segnum;
 401 };
 402
 403 static int nilfs_segment_list_add(struct list_head *head, __u64 segnum)
 404 {
 405         struct nilfs_segment_entry *ent = kmalloc(sizeof(*ent), GFP_NOFS);
 406
 407         if (unlikely(!ent))
 408                 return -ENOMEM;
 409
 410         ent->segnum = segnum;
 411         INIT_LIST_HEAD(&ent->list);
 412         list_add_tail(&ent->list, head);
 413         return 0;
 414 }
 415
 416 void nilfs_dispose_segment_list(struct list_head *head)
 417 {
 418         while (!list_empty(head)) {
 419                 struct nilfs_segment_entry *ent
 420                         = list_entry(head->next,
 421                                      struct nilfs_segment_entry, list);
 422                 list_del(&ent->list);
 423                 kfree(ent);
 424         }
 425 }
 426
 427 static int nilfs_prepare_segment_for_recovery(struct the_nilfs *nilfs,
 428                                               struct nilfs_sb_info *sbi,
 429                                               struct nilfs_recovery_info *ri)
 430 {
 431         struct list_head *head = &ri->ri_used_segments;
 432         struct nilfs_segment_entry *ent, *n;
 433         struct inode *sufile = nilfs->ns_sufile;
 434         __u64 segnum[4];
 435         int err;
 436         int i;
 437
 438         segnum[0] = nilfs->ns_segnum;
 439         segnum[1] = nilfs->ns_nextnum;
 440         segnum[2] = ri->ri_segnum;
 441         segnum[3] = ri->ri_nextnum;
 442
 443         nilfs_attach_writer(nilfs, sbi);
 444         /*
 445          * Releasing the next segment of the latest super root.
 446          * The next segment is invalidated by this recovery.
 447          */
 448         err = nilfs_sufile_free(sufile, segnum[1]);
 449         if (unlikely(err))
 450                 goto failed;
 451
 452         for (i = 1; i < 4; i++) {
 453                 err = nilfs_segment_list_add(head, segnum[i]);
 454                 if (unlikely(err))
 455                         goto failed;
 456         }
 457
 458         /*
 459          * Collecting segments written after the latest super root.
 460          * These are marked dirty to avoid being reallocated in the next write.
 461          */
 462         list_for_each_entry_safe(ent, n, head, list) {
 463                 if (ent->segnum != segnum[0]) {
 464                         err = nilfs_sufile_scrap(sufile, ent->segnum);
 465                         if (unlikely(err))
 466                                 goto failed;
 467                 }
 468                 list_del(&ent->list);
 469                 kfree(ent);
 470         }
 471
 472         /* Allocate new segments for recovery */
 473         err = nilfs_sufile_alloc(sufile, &segnum[0]);
 474         if (unlikely(err))
 475                 goto failed;
 476
 477         nilfs->ns_pseg_offset = 0;
 478         nilfs->ns_seg_seq = ri->ri_seq + 2;
 479         nilfs->ns_nextnum = nilfs->ns_segnum = segnum[0];
 480
 481  failed:
 482         /* No need to recover sufile because it will be destroyed on error */
 483         nilfs_detach_writer(nilfs, sbi);
 484         return err;
 485 }
 486
 487 static int nilfs_recovery_copy_block(struct the_nilfs *nilfs,
 488                                      struct nilfs_recovery_block *rb,
 489                                      struct page *page)
 490 {
 491         struct buffer_head *bh_org;
 492         void *kaddr;
 493
 494         bh_org = __bread(nilfs->ns_bdev, rb->blocknr, nilfs->ns_blocksize);
 495         if (unlikely(!bh_org))
 496                 return -EIO;
 497
 498         kaddr = kmap_atomic(page, KM_USER0);
 499         memcpy(kaddr + bh_offset(bh_org), bh_org->b_data, bh_org->b_size);
 500         kunmap_atomic(kaddr, KM_USER0);
 501         brelse(bh_org);
 502         return 0;
 503 }
 504
 505 static int nilfs_recover_dsync_blocks(struct the_nilfs *nilfs,
 506                                       struct nilfs_sb_info *sbi,
 507                                       struct list_head *head,
 508                                       unsigned long *nr_salvaged_blocks)
 509 {
 510         struct inode *inode;
 511         struct nilfs_recovery_block *rb, *n;
 512         unsigned blocksize = nilfs->ns_blocksize;
 513         struct page *page;
 514         loff_t pos;
 515         int err = 0, err2 = 0;
 516
 517         list_for_each_entry_safe(rb, n, head, list) {
 518                 inode = nilfs_iget(sbi->s_super, rb->ino);
 519                 if (IS_ERR(inode)) {
 520                         err = PTR_ERR(inode);
 521                         inode = NULL;
 522                         goto failed_inode;
 523                 }
 524
 525                 pos = rb->blkoff << inode->i_blkbits;
 526                 page = NULL;
 527                 err = block_write_begin(NULL, inode->i_mapping, pos, blocksize,
 528                                         0, &page, NULL, nilfs_get_block);
 529                 if (unlikely(err))
 530                         goto failed_inode;
 531
 532                 err = nilfs_recovery_copy_block(nilfs, rb, page);
 533                 if (unlikely(err))
 534                         goto failed_page;
 535
 536                 err = nilfs_set_file_dirty(sbi, inode, 1);
 537                 if (unlikely(err))
 538                         goto failed_page;
 539
 540                 block_write_end(NULL, inode->i_mapping, pos, blocksize,
 541                                 blocksize, page, NULL);
 542
 543                 unlock_page(page);
 544                 page_cache_release(page);
 545
 546                 (*nr_salvaged_blocks)++;
 547                 goto next;
 548
 549  failed_page:
 550                 unlock_page(page);
 551                 page_cache_release(page);
 552
 553  failed_inode:
 554                 printk(KERN_WARNING
 555                        "NILFS warning: error recovering data block "
 556                        "(err=%d, ino=%lu, block-offset=%llu)\n",
 557                        err, (unsigned long)rb->ino,
 558                        (unsigned long long)rb->blkoff);
 559                 if (!err2)
 560                         err2 = err;
 561  next:
 562                 iput(inode); /* iput(NULL) is just ignored */
 563                 list_del_init(&rb->list);
 564                 kfree(rb);
 565         }
 566         return err2;
 567 }
 568
 569 /**
 570  * nilfs_do_roll_forward - salvage logical segments newer than the latest
 571  * checkpoint
 572  * @nilfs: nilfs object
 573  * @sbi: nilfs_sb_info
 574  * @ri: pointer to a nilfs_recovery_info
 575  */
 576 static int nilfs_do_roll_forward(struct the_nilfs *nilfs,
 577                                  struct nilfs_sb_info *sbi,
 578                                  struct nilfs_recovery_info *ri)
 579 {
 580         struct buffer_head *bh_sum = NULL;
 581         struct nilfs_segment_summary *sum;
 582         sector_t pseg_start;
 583         sector_t seg_start, seg_end;  /* Starting/ending DBN of full segment */
 584         unsigned long nsalvaged_blocks = 0;
 585         unsigned int flags;
 586         u64 seg_seq;
 587         __u64 segnum, nextnum = 0;
 588         int empty_seg = 0;
 589         int err = 0, ret;
 590         LIST_HEAD(dsync_blocks);  /* list of data blocks to be recovered */
 591         enum {
 592                 RF_INIT_ST,
 593                 RF_DSYNC_ST,   /* scanning data-sync segments */
 594         };
 595         int state = RF_INIT_ST;
 596
 597         nilfs_attach_writer(nilfs, sbi);
 598         pseg_start = ri->ri_lsegs_start;
 599         seg_seq = ri->ri_lsegs_start_seq;
 600         segnum = nilfs_get_segnum_of_block(nilfs, pseg_start);
 601         nilfs_get_segment_range(nilfs, segnum, &seg_start, &seg_end);
 602
 603         while (segnum != ri->ri_segnum || pseg_start <= ri->ri_pseg_start) {
 604                 brelse(bh_sum);
 605                 bh_sum = nilfs_read_log_header(nilfs, pseg_start, &sum);
 606                 if (!bh_sum) {
 607                         err = -EIO;
 608                         goto failed;
 609                 }
 610
 611                 ret = nilfs_validate_log(nilfs, seg_seq, bh_sum, sum);
 612                 if (ret) {
 613                         if (ret == NILFS_SEG_FAIL_IO) {
 614                                 err = -EIO;
 615                                 goto failed;
 616                         }
 617                         goto strayed;
 618                 }
 619
 620                 flags = le16_to_cpu(sum->ss_flags);
 621                 if (flags & NILFS_SS_SR)
 622                         goto confused;
 623
 624                 /* Found a valid partial segment; do recovery actions */
 625                 nextnum = nilfs_get_segnum_of_block(nilfs,
 626                                                     le64_to_cpu(sum->ss_next));
 627                 empty_seg = 0;
 628                 nilfs->ns_ctime = le64_to_cpu(sum->ss_create);
 629                 if (!(flags & NILFS_SS_GC))
 630                         nilfs->ns_nongc_ctime = nilfs->ns_ctime;
 631
 632                 switch (state) {
 633                 case RF_INIT_ST:
 634                         if (!(flags & NILFS_SS_LOGBGN) ||
 635                             !(flags & NILFS_SS_SYNDT))
 636                                 goto try_next_pseg;
 637                         state = RF_DSYNC_ST;
 638                         /* Fall through */
 639                 case RF_DSYNC_ST:
 640                         if (!(flags & NILFS_SS_SYNDT))
 641                                 goto confused;
 642
 643                         err = nilfs_scan_dsync_log(nilfs, pseg_start, sum,
 644                                                    &dsync_blocks);
 645                         if (unlikely(err))
 646                                 goto failed;
 647                         if (flags & NILFS_SS_LOGEND) {
 648                                 err = nilfs_recover_dsync_blocks(
 649                                         nilfs, sbi, &dsync_blocks,
 650                                         &nsalvaged_blocks);
 651                                 if (unlikely(err))
 652                                         goto failed;
 653                                 state = RF_INIT_ST;
 654                         }
 655                         break; /* Fall through to try_next_pseg */
 656                 }
 657
 658  try_next_pseg:
 659                 if (pseg_start == ri->ri_lsegs_end)
 660                         break;
 661                 pseg_start += le32_to_cpu(sum->ss_nblocks);
 662                 if (pseg_start < seg_end)
 663                         continue;
 664                 goto feed_segment;
 665
 666  strayed:
 667                 if (pseg_start == ri->ri_lsegs_end)
 668                         break;
 669
 670  feed_segment:
 671                 /* Looking to the next full segment */
 672                 if (empty_seg++)
 673                         break;
 674                 seg_seq++;
 675                 segnum = nextnum;
 676                 nilfs_get_segment_range(nilfs, segnum, &seg_start, &seg_end);
 677                 pseg_start = seg_start;
 678         }
 679
 680         if (nsalvaged_blocks) {
 681                 printk(KERN_INFO "NILFS (device %s): salvaged %lu blocks\n",
 682                        sbi->s_super->s_id, nsalvaged_blocks);
 683                 ri->ri_need_recovery = NILFS_RECOVERY_ROLLFORWARD_DONE;
 684         }
 685  out:
 686         brelse(bh_sum);
 687         dispose_recovery_list(&dsync_blocks);
 688         nilfs_detach_writer(nilfs, sbi);
 689         return err;
 690
 691  confused:
 692         err = -EINVAL;
 693  failed:
 694         printk(KERN_ERR
 695                "NILFS (device %s): Error roll-forwarding "
 696                "(err=%d, pseg block=%llu). ",
 697                sbi->s_super->s_id, err, (unsigned long long)pseg_start);
 698         goto out;
 699 }
 700
 701 static void nilfs_finish_roll_forward(struct the_nilfs *nilfs,
 702                                       struct nilfs_recovery_info *ri)
 703 {
 704         struct buffer_head *bh;
 705         int err;
 706
 707         if (nilfs_get_segnum_of_block(nilfs, ri->ri_lsegs_start) !=
 708             nilfs_get_segnum_of_block(nilfs, ri->ri_super_root))
 709                 return;
 710
 711         bh = __getblk(nilfs->ns_bdev, ri->ri_lsegs_start, nilfs->ns_blocksize);
 712         BUG_ON(!bh);
 713         memset(bh->b_data, 0, bh->b_size);
 714         set_buffer_dirty(bh);
 715         err = sync_dirty_buffer(bh);
 716         if (unlikely(err))
 717                 printk(KERN_WARNING
 718                        "NILFS warning: buffer sync write failed during "
 719                        "post-cleaning of recovery.\n");
 720         brelse(bh);
 721 }
 722
 723 /**
 724  * nilfs_salvage_orphan_logs - salvage logs written after the latest checkpoint
 725  * @nilfs: nilfs object
 726  * @sbi: nilfs_sb_info
 727  * @ri: pointer to a nilfs_recovery_info struct to store search results.
 728  *
 729  * Return Value: On success, 0 is returned.  On error, one of the following
 730  * negative error code is returned.
 731  *
 732  * %-EINVAL - Inconsistent filesystem state.
 733  *
 734  * %-EIO - I/O error
 735  *
 736  * %-ENOSPC - No space left on device (only in a panic state).
 737  *
 738  * %-ERESTARTSYS - Interrupted.
 739  *
 740  * %-ENOMEM - Insufficient memory available.
 741  */
 742 int nilfs_salvage_orphan_logs(struct the_nilfs *nilfs,
 743                               struct nilfs_sb_info *sbi,
 744                               struct nilfs_recovery_info *ri)
 745 {
 746         int err;
 747
 748         if (ri->ri_lsegs_start == 0 || ri->ri_lsegs_end == 0)
 749                 return 0;
 750
 751         err = nilfs_attach_checkpoint(sbi, ri->ri_cno);
 752         if (unlikely(err)) {
 753                 printk(KERN_ERR
 754                        "NILFS: error loading the latest checkpoint.\n");
 755                 return err;
 756         }
 757
 758         err = nilfs_do_roll_forward(nilfs, sbi, ri);
 759         if (unlikely(err))
 760                 goto failed;
 761
 762         if (ri->ri_need_recovery == NILFS_RECOVERY_ROLLFORWARD_DONE) {
 763                 err = nilfs_prepare_segment_for_recovery(nilfs, sbi, ri);
 764                 if (unlikely(err)) {
 765                         printk(KERN_ERR "NILFS: Error preparing segments for "
 766                                "recovery.\n");
 767                         goto failed;
 768                 }
 769
 770                 err = nilfs_attach_segment_constructor(sbi);
 771                 if (unlikely(err))
 772                         goto failed;
 773
 774                 set_nilfs_discontinued(nilfs);
 775                 err = nilfs_construct_segment(sbi->s_super);
 776                 nilfs_detach_segment_constructor(sbi);
 777
 778                 if (unlikely(err)) {
 779                         printk(KERN_ERR "NILFS: Oops! recovery failed. "
 780                                "(err=%d)\n", err);
 781                         goto failed;
 782                 }
 783
 784                 nilfs_finish_roll_forward(nilfs, ri);
 785         }
 786
 787  failed:
 788         nilfs_detach_checkpoint(sbi);
 789         return err;
 790 }
 791
 792 /**
 793  * nilfs_search_super_root - search the latest valid super root
 794  * @nilfs: the_nilfs
 795  * @ri: pointer to a nilfs_recovery_info struct to store search results.
 796  *
 797  * nilfs_search_super_root() looks for the latest super-root from a partial
 798  * segment pointed by the superblock.  It sets up struct the_nilfs through
 799  * this search. It fills nilfs_recovery_info (ri) required for recovery.
 800  *
 801  * Return Value: On success, 0 is returned.  On error, one of the following
 802  * negative error code is returned.
 803  *
 804  * %-EINVAL - No valid segment found
 805  *
 806  * %-EIO - I/O error
 807  */
 808 int nilfs_search_super_root(struct the_nilfs *nilfs,
 809                             struct nilfs_recovery_info *ri)
 810 {
 811         struct buffer_head *bh_sum = NULL;
 812         struct nilfs_segment_summary *sum;
 813         sector_t pseg_start, pseg_end, sr_pseg_start = 0;
 814         sector_t seg_start, seg_end; /* range of full segment (block number) */
 815         sector_t b, end;
 816         unsigned long nblocks;
 817         unsigned int flags;
 818         u64 seg_seq;
 819         __u64 segnum, nextnum = 0;
 820         __u64 cno;
 821         LIST_HEAD(segments);
 822         int empty_seg = 0, scan_newer = 0;
 823         int ret;
 824
 825         pseg_start = nilfs->ns_last_pseg;
 826         seg_seq = nilfs->ns_last_seq;
 827         cno = nilfs->ns_last_cno;
 828         segnum = nilfs_get_segnum_of_block(nilfs, pseg_start);
 829
 830         /* Calculate range of segment */
 831         nilfs_get_segment_range(nilfs, segnum, &seg_start, &seg_end);
 832
 833         /* Read ahead segment */
 834         b = seg_start;
 835         while (b <= seg_end)
 836                 __breadahead(nilfs->ns_bdev, b++, nilfs->ns_blocksize);
 837
 838         for (;;) {
 839                 brelse(bh_sum);
 840                 ret = NILFS_SEG_FAIL_IO;
 841                 bh_sum = nilfs_read_log_header(nilfs, pseg_start, &sum);
 842                 if (!bh_sum)
 843                         goto failed;
 844
 845                 ret = nilfs_validate_log(nilfs, seg_seq, bh_sum, sum);
 846                 if (ret) {
 847                         if (ret == NILFS_SEG_FAIL_IO)
 848                                 goto failed;
 849                         goto strayed;
 850                 }
 851
 852                 nblocks = le32_to_cpu(sum->ss_nblocks);
 853                 pseg_end = pseg_start + nblocks - 1;
 854                 if (unlikely(pseg_end > seg_end)) {
 855                         ret = NILFS_SEG_FAIL_CONSISTENCY;
 856                         goto strayed;
 857                 }
 858
 859                 /* A valid partial segment */
 860                 ri->ri_pseg_start = pseg_start;
 861                 ri->ri_seq = seg_seq;
 862                 ri->ri_segnum = segnum;
 863                 nextnum = nilfs_get_segnum_of_block(nilfs,
 864                                                     le64_to_cpu(sum->ss_next));
 865                 ri->ri_nextnum = nextnum;
 866                 empty_seg = 0;
 867
 868                 flags = le16_to_cpu(sum->ss_flags);
 869                 if (!(flags & NILFS_SS_SR) && !scan_newer) {
 870                         /* This will never happen because a superblock
 871                            (last_segment) always points to a pseg
 872                            having a super root. */
 873                         ret = NILFS_SEG_FAIL_CONSISTENCY;
 874                         goto failed;
 875                 }
 876
 877                 if (pseg_start == seg_start) {
 878                         nilfs_get_segment_range(nilfs, nextnum, &b, &end);
 879                         while (b <= end)
 880                                 __breadahead(nilfs->ns_bdev, b++,
 881                                              nilfs->ns_blocksize);
 882                 }
 883                 if (!(flags & NILFS_SS_SR)) {
 884                         if (!ri->ri_lsegs_start && (flags & NILFS_SS_LOGBGN)) {
 885                                 ri->ri_lsegs_start = pseg_start;
 886                                 ri->ri_lsegs_start_seq = seg_seq;
 887                         }
 888                         if (flags & NILFS_SS_LOGEND)
 889                                 ri->ri_lsegs_end = pseg_start;
 890                         goto try_next_pseg;
 891                 }
 892
 893                 /* A valid super root was found. */
 894                 ri->ri_cno = cno++;
 895                 ri->ri_super_root = pseg_end;
 896                 ri->ri_lsegs_start = ri->ri_lsegs_end = 0;
 897
 898                 nilfs_dispose_segment_list(&segments);
 899                 sr_pseg_start = pseg_start;
 900                 nilfs->ns_pseg_offset = pseg_start + nblocks - seg_start;
 901                 nilfs->ns_seg_seq = seg_seq;
 902                 nilfs->ns_segnum = segnum;
 903                 nilfs->ns_cno = cno;  /* nilfs->ns_cno = ri->ri_cno + 1 */
 904                 nilfs->ns_ctime = le64_to_cpu(sum->ss_create);
 905                 nilfs->ns_nextnum = nextnum;
 906
 907                 if (scan_newer)
 908                         ri->ri_need_recovery = NILFS_RECOVERY_SR_UPDATED;
 909                 else {
 910                         if (nilfs->ns_mount_state & NILFS_VALID_FS)
 911                                 goto super_root_found;
 912                         scan_newer = 1;
 913                 }
 914
 915  try_next_pseg:
 916                 /* Standing on a course, or met an inconsistent state */
 917                 pseg_start += nblocks;
 918                 if (pseg_start < seg_end)
 919                         continue;
 920                 goto feed_segment;
 921
 922  strayed:
 923                 /* Off the trail */
 924                 if (!scan_newer)
 925                         /*
 926                          * This can happen if a checkpoint was written without
 927                          * barriers, or as a result of an I/O failure.
 928                          */
 929                         goto failed;
 930
 931  feed_segment:
 932                 /* Looking to the next full segment */
 933                 if (empty_seg++)
 934                         goto super_root_found; /* found a valid super root */
 935
 936                 ret = nilfs_segment_list_add(&segments, segnum);
 937                 if (unlikely(ret))
 938                         goto failed;
 939
 940                 seg_seq++;
 941                 segnum = nextnum;
 942                 nilfs_get_segment_range(nilfs, segnum, &seg_start, &seg_end);
 943                 pseg_start = seg_start;
 944         }
 945
 946  super_root_found:
 947         /* Updating pointers relating to the latest checkpoint */
 948         brelse(bh_sum);
 949         list_splice_tail(&segments, &ri->ri_used_segments);
 950         nilfs->ns_last_pseg = sr_pseg_start;
 951         nilfs->ns_last_seq = nilfs->ns_seg_seq;
 952         nilfs->ns_last_cno = ri->ri_cno;
 953         return 0;
 954
 955  failed:
 956         brelse(bh_sum);
 957         nilfs_dispose_segment_list(&segments);
 958         return (ret < 0) ? ret : nilfs_warn_segment_error(ret);
 959 }