diff options
Diffstat (limited to 'fs/nilfs2/recovery.c')
| -rw-r--r-- | fs/nilfs2/recovery.c | 954 |
1 files changed, 954 insertions, 0 deletions
diff --git a/fs/nilfs2/recovery.c b/fs/nilfs2/recovery.c new file mode 100644 index 000000000..140b663e9 --- /dev/null +++ b/fs/nilfs2/recovery.c @@ -0,0 +1,954 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * recovery.c - NILFS recovery logic + * + * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation. + * + * 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); +} |