/* * recovery.c - NILFS recovery logic * * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * Written by Ryusuke Konishi. */ #include <linux/buffer_head.h> #include <linux/blkdev.h> #include <linux/swap.h> #include <linux/slab.h> #include <linux/crc32.h> #include "nilfs.h" #include "segment.h" #include "sufile.h" #include "page.h" #include "segbuf.h" /* * Segment check result */ enum { NILFS_SEG_VALID, NILFS_SEG_NO_SUPER_ROOT, NILFS_SEG_FAIL_IO, NILFS_SEG_FAIL_MAGIC, NILFS_SEG_FAIL_SEQ, NILFS_SEG_FAIL_CHECKSUM_SUPER_ROOT, NILFS_SEG_FAIL_CHECKSUM_FULL, NILFS_SEG_FAIL_CONSISTENCY, }; /* work structure for recovery */ struct nilfs_recovery_block { ino_t ino; /* * Inode number of the file that this block * belongs to */ sector_t blocknr; /* block number */ __u64 vblocknr; /* virtual block number */ unsigned long blkoff; /* File offset of the data block (per block) */ struct list_head list; }; static int nilfs_warn_segment_error(struct super_block *sb, int err) { const char *msg = NULL; switch (err) { case NILFS_SEG_FAIL_IO: nilfs_msg(sb, KERN_ERR, "I/O error reading segment"); return -EIO; case NILFS_SEG_FAIL_MAGIC: msg = "Magic number mismatch"; break; case NILFS_SEG_FAIL_SEQ: msg = "Sequence number mismatch"; break; case NILFS_SEG_FAIL_CHECKSUM_SUPER_ROOT: msg = "Checksum error in super root"; break; case NILFS_SEG_FAIL_CHECKSUM_FULL: msg = "Checksum error in segment payload"; break; case NILFS_SEG_FAIL_CONSISTENCY: msg = "Inconsistency found"; break; case NILFS_SEG_NO_SUPER_ROOT: msg = "No super root in the last segment"; break; default: nilfs_msg(sb, KERN_ERR, "unrecognized segment error %d", err); return -EINVAL; } nilfs_msg(sb, KERN_WARNING, "invalid segment: %s", msg); return -EINVAL; } /** * nilfs_compute_checksum - compute checksum of blocks continuously * @nilfs: nilfs object * @bhs: buffer head of start block * @sum: place to store result * @offset: offset bytes in the first block * @check_bytes: number of bytes to be checked * @start: DBN of start block * @nblock: number of blocks to be checked */ static int nilfs_compute_checksum(struct the_nilfs *nilfs, struct buffer_head *bhs, u32 *sum, unsigned long offset, u64 check_bytes, sector_t start, unsigned long nblock) { unsigned int blocksize = nilfs->ns_blocksize; unsigned long size; u32 crc; BUG_ON(offset >= blocksize); check_bytes -= offset; size = min_t(u64, check_bytes, blocksize - offset); crc = crc32_le(nilfs->ns_crc_seed, (unsigned char *)bhs->b_data + offset, size); if (--nblock > 0) { do { struct buffer_head *bh; bh = __bread(nilfs->ns_bdev, ++start, blocksize); if (!bh) return -EIO; check_bytes -= size; size = min_t(u64, check_bytes, blocksize); crc = crc32_le(crc, bh->b_data, size); brelse(bh); } while (--nblock > 0); } *sum = crc; return 0; } /** * nilfs_read_super_root_block - read super root block * @nilfs: nilfs object * @sr_block: disk block number of the super root block * @pbh: address of a buffer_head pointer to return super root buffer * @check: CRC check flag */ int nilfs_read_super_root_block(struct the_nilfs *nilfs, sector_t sr_block, struct buffer_head **pbh, int check) { struct buffer_head *bh_sr; struct nilfs_super_root *sr; u32 crc; int ret; *pbh = NULL; bh_sr = __bread(nilfs->ns_bdev, sr_block, nilfs->ns_blocksize); if (unlikely(!bh_sr)) { ret = NILFS_SEG_FAIL_IO; goto failed; } sr = (struct nilfs_super_root *)bh_sr->b_data; if (check) { unsigned int bytes = le16_to_cpu(sr->sr_bytes); if (bytes == 0 || bytes > nilfs->ns_blocksize) { ret = NILFS_SEG_FAIL_CHECKSUM_SUPER_ROOT; goto failed_bh; } if (nilfs_compute_checksum( nilfs, bh_sr, &crc, sizeof(sr->sr_sum), bytes, sr_block, 1)) { ret = NILFS_SEG_FAIL_IO; goto failed_bh; } if (crc != le32_to_cpu(sr->sr_sum)) { ret = NILFS_SEG_FAIL_CHECKSUM_SUPER_ROOT; goto failed_bh; } } *pbh = bh_sr; return 0; failed_bh: brelse(bh_sr); failed: return nilfs_warn_segment_error(nilfs->ns_sb, ret); } /** * nilfs_read_log_header - read summary header of the specified log * @nilfs: nilfs object * @start_blocknr: start block number of the log * @sum: pointer to return segment summary structure */ static struct buffer_head * nilfs_read_log_header(struct the_nilfs *nilfs, sector_t start_blocknr, struct nilfs_segment_summary **sum) { struct buffer_head *bh_sum; bh_sum = __bread(nilfs->ns_bdev, start_blocknr, nilfs->ns_blocksize); if (bh_sum) *sum = (struct nilfs_segment_summary *)bh_sum->b_data; return bh_sum; } /** * nilfs_validate_log - verify consistency of log * @nilfs: nilfs object * @seg_seq: sequence number of segment * @bh_sum: buffer head of summary block * @sum: segment summary struct */ static int nilfs_validate_log(struct the_nilfs *nilfs, u64 seg_seq, struct buffer_head *bh_sum, struct nilfs_segment_summary *sum) { unsigned long nblock; u32 crc; int ret; ret = NILFS_SEG_FAIL_MAGIC; if (le32_to_cpu(sum->ss_magic) != NILFS_SEGSUM_MAGIC) goto out; ret = NILFS_SEG_FAIL_SEQ; if (le64_to_cpu(sum->ss_seq) != seg_seq) goto out; nblock = le32_to_cpu(sum->ss_nblocks); ret = NILFS_SEG_FAIL_CONSISTENCY; if (unlikely(nblock == 0 || nblock > nilfs->ns_blocks_per_segment)) /* This limits the number of blocks read in the CRC check */ goto out; ret = NILFS_SEG_FAIL_IO; if (nilfs_compute_checksum(nilfs, bh_sum, &crc, sizeof(sum->ss_datasum), ((u64)nblock << nilfs->ns_blocksize_bits), bh_sum->b_blocknr, nblock)) goto out; ret = NILFS_SEG_FAIL_CHECKSUM_FULL; if (crc != le32_to_cpu(sum->ss_datasum)) goto out; ret = 0; out: return ret; } /** * nilfs_read_summary_info - read an item on summary blocks of a log * @nilfs: nilfs object * @pbh: the current buffer head on summary blocks [in, out] * @offset: the current byte offset on summary blocks [in, out] * @bytes: byte size of the item to be read */ static void *nilfs_read_summary_info(struct the_nilfs *nilfs, struct buffer_head **pbh, unsigned int *offset, unsigned int bytes) { void *ptr; sector_t blocknr; BUG_ON((*pbh)->b_size < *offset); if (bytes > (*pbh)->b_size - *offset) { blocknr = (*pbh)->b_blocknr; brelse(*pbh); *pbh = __bread(nilfs->ns_bdev, blocknr + 1, nilfs->ns_blocksize); if (unlikely(!*pbh)) return NULL; *offset = 0; } ptr = (*pbh)->b_data + *offset; *offset += bytes; return ptr; } /** * nilfs_skip_summary_info - skip items on summary blocks of a log * @nilfs: nilfs object * @pbh: the current buffer head on summary blocks [in, out] * @offset: the current byte offset on summary blocks [in, out] * @bytes: byte size of the item to be skipped * @count: number of items to be skipped */ static void nilfs_skip_summary_info(struct the_nilfs *nilfs, struct buffer_head **pbh, unsigned int *offset, unsigned int bytes, unsigned long count) { unsigned int rest_item_in_current_block = ((*pbh)->b_size - *offset) / bytes; if (count <= rest_item_in_current_block) { *offset += bytes * count; } else { sector_t blocknr = (*pbh)->b_blocknr; unsigned int nitem_per_block = (*pbh)->b_size / bytes; unsigned int bcnt; count -= rest_item_in_current_block; bcnt = DIV_ROUND_UP(count, nitem_per_block); *offset = bytes * (count - (bcnt - 1) * nitem_per_block); brelse(*pbh); *pbh = __bread(nilfs->ns_bdev, blocknr + bcnt, nilfs->ns_blocksize); } } /** * nilfs_scan_dsync_log - get block information of a log written for data sync * @nilfs: nilfs object * @start_blocknr: start block number of the log * @sum: log summary information * @head: list head to add nilfs_recovery_block struct */ static int nilfs_scan_dsync_log(struct the_nilfs *nilfs, sector_t start_blocknr, struct nilfs_segment_summary *sum, struct list_head *head) { struct buffer_head *bh; unsigned int offset; u32 nfinfo, sumbytes; sector_t blocknr; ino_t ino; int err = -EIO; nfinfo = le32_to_cpu(sum->ss_nfinfo); if (!nfinfo) return 0; sumbytes = le32_to_cpu(sum->ss_sumbytes); blocknr = start_blocknr + DIV_ROUND_UP(sumbytes, nilfs->ns_blocksize); bh = __bread(nilfs->ns_bdev, start_blocknr, nilfs->ns_blocksize); if (unlikely(!bh)) goto out; offset = le16_to_cpu(sum->ss_bytes); for (;;) { unsigned long nblocks, ndatablk, nnodeblk; struct nilfs_finfo *finfo; finfo = nilfs_read_summary_info(nilfs, &bh, &offset, sizeof(*finfo)); if (unlikely(!finfo)) goto out; ino = le64_to_cpu(finfo->fi_ino); nblocks = le32_to_cpu(finfo->fi_nblocks); ndatablk = le32_to_cpu(finfo->fi_ndatablk); nnodeblk = nblocks - ndatablk; while (ndatablk-- > 0) { struct nilfs_recovery_block *rb; struct nilfs_binfo_v *binfo; binfo = nilfs_read_summary_info(nilfs, &bh, &offset, sizeof(*binfo)); if (unlikely(!binfo)) goto out; rb = kmalloc(sizeof(*rb), GFP_NOFS); if (unlikely(!rb)) { err = -ENOMEM; goto out; } rb->ino = ino; rb->blocknr = blocknr++; rb->vblocknr = le64_to_cpu(binfo->bi_vblocknr); rb->blkoff = le64_to_cpu(binfo->bi_blkoff); /* INIT_LIST_HEAD(&rb->list); */ list_add_tail(&rb->list, head); } if (--nfinfo == 0) break; blocknr += nnodeblk; /* always 0 for data sync logs */ nilfs_skip_summary_info(nilfs, &bh, &offset, sizeof(__le64), nnodeblk); if (unlikely(!bh)) goto out; } err = 0; out: brelse(bh); /* brelse(NULL) is just ignored */ return err; } static void dispose_recovery_list(struct list_head *head) { while (!list_empty(head)) { struct nilfs_recovery_block *rb; rb = list_first_entry(head, struct nilfs_recovery_block, list); list_del(&rb->list); kfree(rb); } } struct nilfs_segment_entry { struct list_head list; __u64 segnum; }; static int nilfs_segment_list_add(struct list_head *head, __u64 segnum) { struct nilfs_segment_entry *ent = kmalloc(sizeof(*ent), GFP_NOFS); if (unlikely(!ent)) return -ENOMEM; ent->segnum = segnum; INIT_LIST_HEAD(&ent->list); list_add_tail(&ent->list, head); return 0; } void nilfs_dispose_segment_list(struct list_head *head) { while (!list_empty(head)) { struct nilfs_segment_entry *ent; ent = list_first_entry(head, struct nilfs_segment_entry, list); list_del(&ent->list); kfree(ent); } } static int nilfs_prepare_segment_for_recovery(struct the_nilfs *nilfs, struct super_block *sb, struct nilfs_recovery_info *ri) { struct list_head *head = &ri->ri_used_segments; struct nilfs_segment_entry *ent, *n; struct inode *sufile = nilfs->ns_sufile; __u64 segnum[4]; int err; int i; segnum[0] = nilfs->ns_segnum; segnum[1] = nilfs->ns_nextnum; segnum[2] = ri->ri_segnum; segnum[3] = ri->ri_nextnum; /* * Releasing the next segment of the latest super root. * The next segment is invalidated by this recovery. */ err = nilfs_sufile_free(sufile, segnum[1]); if (unlikely(err)) goto failed; for (i = 1; i < 4; i++) { err = nilfs_segment_list_add(head, segnum[i]); if (unlikely(err)) goto failed; } /* * Collecting segments written after the latest super root. * These are marked dirty to avoid being reallocated in the next write. */ list_for_each_entry_safe(ent, n, head, list) { if (ent->segnum != segnum[0]) { err = nilfs_sufile_scrap(sufile, ent->segnum); if (unlikely(err)) goto failed; } list_del(&ent->list); kfree(ent); } /* Allocate new segments for recovery */ err = nilfs_sufile_alloc(sufile, &segnum[0]); if (unlikely(err)) goto failed; nilfs->ns_pseg_offset = 0; nilfs->ns_seg_seq = ri->ri_seq + 2; nilfs->ns_nextnum = nilfs->ns_segnum = segnum[0]; failed: /* No need to recover sufile because it will be destroyed on error */ return err; } static int nilfs_recovery_copy_block(struct the_nilfs *nilfs, struct nilfs_recovery_block *rb, struct page *page) { struct buffer_head *bh_org; void *kaddr; bh_org = __bread(nilfs->ns_bdev, rb->blocknr, nilfs->ns_blocksize); if (unlikely(!bh_org)) return -EIO; kaddr = kmap_atomic(page); memcpy(kaddr + bh_offset(bh_org), bh_org->b_data, bh_org->b_size); kunmap_atomic(kaddr); brelse(bh_org); return 0; } static int nilfs_recover_dsync_blocks(struct the_nilfs *nilfs, struct super_block *sb, struct nilfs_root *root, struct list_head *head, unsigned long *nr_salvaged_blocks) { struct inode *inode; struct nilfs_recovery_block *rb, *n; unsigned int blocksize = nilfs->ns_blocksize; struct page *page; loff_t pos; int err = 0, err2 = 0; list_for_each_entry_safe(rb, n, head, list) { inode = nilfs_iget(sb, root, rb->ino); if (IS_ERR(inode)) { err = PTR_ERR(inode); inode = NULL; goto failed_inode; } pos = rb->blkoff << inode->i_blkbits; err = block_write_begin(inode->i_mapping, pos, blocksize, 0, &page, nilfs_get_block); if (unlikely(err)) { loff_t isize = inode->i_size; if (pos + blocksize > isize) nilfs_write_failed(inode->i_mapping, pos + blocksize); goto failed_inode; } err = nilfs_recovery_copy_block(nilfs, rb, page); if (unlikely(err)) goto failed_page; err = nilfs_set_file_dirty(inode, 1); if (unlikely(err)) goto failed_page; block_write_end(NULL, inode->i_mapping, pos, blocksize, blocksize, page, NULL); unlock_page(page); put_page(page); (*nr_salvaged_blocks)++; goto next; failed_page: unlock_page(page); put_page(page); failed_inode: nilfs_msg(sb, KERN_WARNING, "error %d recovering data block (ino=%lu, block-offset=%llu)", err, (unsigned long)rb->ino, (unsigned long long)rb->blkoff); if (!err2) err2 = err; next: iput(inode); /* iput(NULL) is just ignored */ list_del_init(&rb->list); kfree(rb); } return err2; } /** * nilfs_do_roll_forward - salvage logical segments newer than the latest * checkpoint * @nilfs: nilfs object * @sb: super block instance * @ri: pointer to a nilfs_recovery_info */ static int nilfs_do_roll_forward(struct the_nilfs *nilfs, struct super_block *sb, struct nilfs_root *root, struct nilfs_recovery_info *ri) { struct buffer_head *bh_sum = NULL; struct nilfs_segment_summary *sum = NULL; sector_t pseg_start; sector_t seg_start, seg_end; /* Starting/ending DBN of full segment */ unsigned long nsalvaged_blocks = 0; unsigned int flags; u64 seg_seq; __u64 segnum, nextnum = 0; int empty_seg = 0; int err = 0, ret; LIST_HEAD(dsync_blocks); /* list of data blocks to be recovered */ enum { RF_INIT_ST, RF_DSYNC_ST, /* scanning data-sync segments */ }; int state = RF_INIT_ST; pseg_start = ri->ri_lsegs_start; seg_seq = ri->ri_lsegs_start_seq; segnum = nilfs_get_segnum_of_block(nilfs, pseg_start); nilfs_get_segment_range(nilfs, segnum, &seg_start, &seg_end); while (segnum != ri->ri_segnum || pseg_start <= ri->ri_pseg_start) { brelse(bh_sum); bh_sum = nilfs_read_log_header(nilfs, pseg_start, &sum); if (!bh_sum) { err = -EIO; goto failed; } ret = nilfs_validate_log(nilfs, seg_seq, bh_sum, sum); if (ret) { if (ret == NILFS_SEG_FAIL_IO) { err = -EIO; goto failed; } goto strayed; } flags = le16_to_cpu(sum->ss_flags); if (flags & NILFS_SS_SR) goto confused; /* Found a valid partial segment; do recovery actions */ nextnum = nilfs_get_segnum_of_block(nilfs, le64_to_cpu(sum->ss_next)); empty_seg = 0; nilfs->ns_ctime = le64_to_cpu(sum->ss_create); if (!(flags & NILFS_SS_GC)) nilfs->ns_nongc_ctime = nilfs->ns_ctime; switch (state) { case RF_INIT_ST: if (!(flags & NILFS_SS_LOGBGN) || !(flags & NILFS_SS_SYNDT)) goto try_next_pseg; state = RF_DSYNC_ST; /* Fall through */ case RF_DSYNC_ST: if (!(flags & NILFS_SS_SYNDT)) goto confused; err = nilfs_scan_dsync_log(nilfs, pseg_start, sum, &dsync_blocks); if (unlikely(err)) goto failed; if (flags & NILFS_SS_LOGEND) { err = nilfs_recover_dsync_blocks( nilfs, sb, root, &dsync_blocks, &nsalvaged_blocks); if (unlikely(err)) goto failed; state = RF_INIT_ST; } break; /* Fall through to try_next_pseg */ } try_next_pseg: if (pseg_start == ri->ri_lsegs_end) break; pseg_start += le32_to_cpu(sum->ss_nblocks); if (pseg_start < seg_end) continue; goto feed_segment; strayed: if (pseg_start == ri->ri_lsegs_end) break; feed_segment: /* Looking to the next full segment */ if (empty_seg++) break; seg_seq++; segnum = nextnum; nilfs_get_segment_range(nilfs, segnum, &seg_start, &seg_end); pseg_start = seg_start; } if (nsalvaged_blocks) { nilfs_msg(sb, KERN_INFO, "salvaged %lu blocks", nsalvaged_blocks); ri->ri_need_recovery = NILFS_RECOVERY_ROLLFORWARD_DONE; } out: brelse(bh_sum); dispose_recovery_list(&dsync_blocks); return err; confused: err = -EINVAL; failed: nilfs_msg(sb, KERN_ERR, "error %d roll-forwarding partial segment at blocknr = %llu", err, (unsigned long long)pseg_start); goto out; } static void nilfs_finish_roll_forward(struct the_nilfs *nilfs, struct nilfs_recovery_info *ri) { struct buffer_head *bh; int err; if (nilfs_get_segnum_of_block(nilfs, ri->ri_lsegs_start) != nilfs_get_segnum_of_block(nilfs, ri->ri_super_root)) return; bh = __getblk(nilfs->ns_bdev, ri->ri_lsegs_start, nilfs->ns_blocksize); BUG_ON(!bh); memset(bh->b_data, 0, bh->b_size); set_buffer_dirty(bh); err = sync_dirty_buffer(bh); if (unlikely(err)) nilfs_msg(nilfs->ns_sb, KERN_WARNING, "buffer sync write failed during post-cleaning of recovery."); brelse(bh); } /** * nilfs_salvage_orphan_logs - salvage logs written after the latest checkpoint * @nilfs: nilfs object * @sb: super block instance * @ri: pointer to a nilfs_recovery_info struct to store search results. * * Return Value: On success, 0 is returned. On error, one of the following * negative error code is returned. * * %-EINVAL - Inconsistent filesystem state. * * %-EIO - I/O error * * %-ENOSPC - No space left on device (only in a panic state). * * %-ERESTARTSYS - Interrupted. * * %-ENOMEM - Insufficient memory available. */ int nilfs_salvage_orphan_logs(struct the_nilfs *nilfs, struct super_block *sb, struct nilfs_recovery_info *ri) { struct nilfs_root *root; int err; if (ri->ri_lsegs_start == 0 || ri->ri_lsegs_end == 0) return 0; err = nilfs_attach_checkpoint(sb, ri->ri_cno, true, &root); if (unlikely(err)) { nilfs_msg(sb, KERN_ERR, "error %d loading the latest checkpoint", err); return err; } err = nilfs_do_roll_forward(nilfs, sb, root, ri); if (unlikely(err)) goto failed; if (ri->ri_need_recovery == NILFS_RECOVERY_ROLLFORWARD_DONE) { err = nilfs_prepare_segment_for_recovery(nilfs, sb, ri); if (unlikely(err)) { nilfs_msg(sb, KERN_ERR, "error %d preparing segment for recovery", err); goto failed; } err = nilfs_attach_log_writer(sb, root); if (unlikely(err)) goto failed; set_nilfs_discontinued(nilfs); err = nilfs_construct_segment(sb); nilfs_detach_log_writer(sb); if (unlikely(err)) { nilfs_msg(sb, KERN_ERR, "error %d writing segment for recovery", err); goto failed; } nilfs_finish_roll_forward(nilfs, ri); } failed: nilfs_put_root(root); return err; } /** * nilfs_search_super_root - search the latest valid super root * @nilfs: the_nilfs * @ri: pointer to a nilfs_recovery_info struct to store search results. * * nilfs_search_super_root() looks for the latest super-root from a partial * segment pointed by the superblock. It sets up struct the_nilfs through * this search. It fills nilfs_recovery_info (ri) required for recovery. * * Return Value: On success, 0 is returned. On error, one of the following * negative error code is returned. * * %-EINVAL - No valid segment found * * %-EIO - I/O error * * %-ENOMEM - Insufficient memory available. */ int nilfs_search_super_root(struct the_nilfs *nilfs, struct nilfs_recovery_info *ri) { struct buffer_head *bh_sum = NULL; struct nilfs_segment_summary *sum = NULL; sector_t pseg_start, pseg_end, sr_pseg_start = 0; sector_t seg_start, seg_end; /* range of full segment (block number) */ sector_t b, end; unsigned long nblocks; unsigned int flags; u64 seg_seq; __u64 segnum, nextnum = 0; __u64 cno; LIST_HEAD(segments); int empty_seg = 0, scan_newer = 0; int ret; pseg_start = nilfs->ns_last_pseg; seg_seq = nilfs->ns_last_seq; cno = nilfs->ns_last_cno; segnum = nilfs_get_segnum_of_block(nilfs, pseg_start); /* Calculate range of segment */ nilfs_get_segment_range(nilfs, segnum, &seg_start, &seg_end); /* Read ahead segment */ b = seg_start; while (b <= seg_end) __breadahead(nilfs->ns_bdev, b++, nilfs->ns_blocksize); for (;;) { brelse(bh_sum); ret = NILFS_SEG_FAIL_IO; bh_sum = nilfs_read_log_header(nilfs, pseg_start, &sum); if (!bh_sum) goto failed; ret = nilfs_validate_log(nilfs, seg_seq, bh_sum, sum); if (ret) { if (ret == NILFS_SEG_FAIL_IO) goto failed; goto strayed; } nblocks = le32_to_cpu(sum->ss_nblocks); pseg_end = pseg_start + nblocks - 1; if (unlikely(pseg_end > seg_end)) { ret = NILFS_SEG_FAIL_CONSISTENCY; goto strayed; } /* A valid partial segment */ ri->ri_pseg_start = pseg_start; ri->ri_seq = seg_seq; ri->ri_segnum = segnum; nextnum = nilfs_get_segnum_of_block(nilfs, le64_to_cpu(sum->ss_next)); ri->ri_nextnum = nextnum; empty_seg = 0; flags = le16_to_cpu(sum->ss_flags); if (!(flags & NILFS_SS_SR) && !scan_newer) { /* * This will never happen because a superblock * (last_segment) always points to a pseg with * a super root. */ ret = NILFS_SEG_FAIL_CONSISTENCY; goto failed; } if (pseg_start == seg_start) { nilfs_get_segment_range(nilfs, nextnum, &b, &end); while (b <= end) __breadahead(nilfs->ns_bdev, b++, nilfs->ns_blocksize); } if (!(flags & NILFS_SS_SR)) { if (!ri->ri_lsegs_start && (flags & NILFS_SS_LOGBGN)) { ri->ri_lsegs_start = pseg_start; ri->ri_lsegs_start_seq = seg_seq; } if (flags & NILFS_SS_LOGEND) ri->ri_lsegs_end = pseg_start; goto try_next_pseg; } /* A valid super root was found. */ ri->ri_cno = cno++; ri->ri_super_root = pseg_end; ri->ri_lsegs_start = ri->ri_lsegs_end = 0; nilfs_dispose_segment_list(&segments); sr_pseg_start = pseg_start; nilfs->ns_pseg_offset = pseg_start + nblocks - seg_start; nilfs->ns_seg_seq = seg_seq; nilfs->ns_segnum = segnum; nilfs->ns_cno = cno; /* nilfs->ns_cno = ri->ri_cno + 1 */ nilfs->ns_ctime = le64_to_cpu(sum->ss_create); nilfs->ns_nextnum = nextnum; if (scan_newer) ri->ri_need_recovery = NILFS_RECOVERY_SR_UPDATED; else { if (nilfs->ns_mount_state & NILFS_VALID_FS) goto super_root_found; scan_newer = 1; } try_next_pseg: /* Standing on a course, or met an inconsistent state */ pseg_start += nblocks; if (pseg_start < seg_end) continue; goto feed_segment; strayed: /* Off the trail */ if (!scan_newer) /* * This can happen if a checkpoint was written without * barriers, or as a result of an I/O failure. */ goto failed; feed_segment: /* Looking to the next full segment */ if (empty_seg++) goto super_root_found; /* found a valid super root */ ret = nilfs_segment_list_add(&segments, segnum); if (unlikely(ret)) goto failed; seg_seq++; segnum = nextnum; nilfs_get_segment_range(nilfs, segnum, &seg_start, &seg_end); pseg_start = seg_start; } super_root_found: /* Updating pointers relating to the latest checkpoint */ brelse(bh_sum); list_splice_tail(&segments, &ri->ri_used_segments); nilfs->ns_last_pseg = sr_pseg_start; nilfs->ns_last_seq = nilfs->ns_seg_seq; nilfs->ns_last_cno = ri->ri_cno; return 0; failed: brelse(bh_sum); nilfs_dispose_segment_list(&segments); return ret < 0 ? ret : nilfs_warn_segment_error(nilfs->ns_sb, ret); }