diff options
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/nilfs2/recovery.c | 941 |
1 files changed, 941 insertions, 0 deletions
diff --git a/fs/nilfs2/recovery.c b/fs/nilfs2/recovery.c new file mode 100644 index 00000000000..877dc1ba23f --- /dev/null +++ b/fs/nilfs2/recovery.c @@ -0,0 +1,941 @@ +/* + * 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. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA + * + * Written by Ryusuke Konishi <ryusuke@osrg.net> + */ + +#include <linux/buffer_head.h> +#include <linux/blkdev.h> +#include <linux/swap.h> +#include <linux/crc32.h> +#include "nilfs.h" +#include "segment.h" +#include "sufile.h" +#include "page.h" +#include "seglist.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_SEGSUM, + 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(int err) +{ + switch (err) { + case NILFS_SEG_FAIL_IO: + printk(KERN_WARNING + "NILFS warning: I/O error on loading last segment\n"); + return -EIO; + case NILFS_SEG_FAIL_MAGIC: + printk(KERN_WARNING + "NILFS warning: Segment magic number invalid\n"); + break; + case NILFS_SEG_FAIL_SEQ: + printk(KERN_WARNING + "NILFS warning: Sequence number mismatch\n"); + break; + case NILFS_SEG_FAIL_CHECKSUM_SEGSUM: + printk(KERN_WARNING + "NILFS warning: Checksum error in segment summary\n"); + break; + case NILFS_SEG_FAIL_CHECKSUM_SUPER_ROOT: + printk(KERN_WARNING + "NILFS warning: Checksum error in super root\n"); + break; + case NILFS_SEG_FAIL_CHECKSUM_FULL: + printk(KERN_WARNING + "NILFS warning: Checksum error in segment payload\n"); + break; + case NILFS_SEG_FAIL_CONSISTENCY: + printk(KERN_WARNING + "NILFS warning: Inconsistent segment\n"); + break; + case NILFS_SEG_NO_SUPER_ROOT: + printk(KERN_WARNING + "NILFS warning: No super root in the last segment\n"); + break; + case NILFS_SEG_VALID: + default: + BUG(); + } + return -EINVAL; +} + +static void store_segsum_info(struct nilfs_segsum_info *ssi, + struct nilfs_segment_summary *sum, + unsigned int blocksize) +{ + ssi->flags = le16_to_cpu(sum->ss_flags); + ssi->seg_seq = le64_to_cpu(sum->ss_seq); + ssi->ctime = le64_to_cpu(sum->ss_create); + ssi->next = le64_to_cpu(sum->ss_next); + ssi->nblocks = le32_to_cpu(sum->ss_nblocks); + ssi->nfinfo = le32_to_cpu(sum->ss_nfinfo); + ssi->sumbytes = le32_to_cpu(sum->ss_sumbytes); + + ssi->nsumblk = DIV_ROUND_UP(ssi->sumbytes, blocksize); + ssi->nfileblk = ssi->nblocks - ssi->nsumblk - !!NILFS_SEG_HAS_SR(ssi); +} + +/** + * calc_crc_cont - check CRC of blocks continuously + * @sbi: nilfs_sb_info + * @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 calc_crc_cont(struct nilfs_sb_info *sbi, struct buffer_head *bhs, + u32 *sum, unsigned long offset, u64 check_bytes, + sector_t start, unsigned long nblock) +{ + unsigned long blocksize = sbi->s_super->s_blocksize; + unsigned long size; + u32 crc; + + BUG_ON(offset >= blocksize); + check_bytes -= offset; + size = min_t(u64, check_bytes, blocksize - offset); + crc = crc32_le(sbi->s_nilfs->ns_crc_seed, + (unsigned char *)bhs->b_data + offset, size); + if (--nblock > 0) { + do { + struct buffer_head *bh + = sb_bread(sbi->s_super, ++start); + 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 + * @sb: super_block + * @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 super_block *sb, 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 = sb_bread(sb, sr_block); + if (unlikely(!bh_sr)) { + ret = NILFS_SEG_FAIL_IO; + goto failed; + } + + sr = (struct nilfs_super_root *)bh_sr->b_data; + if (check) { + unsigned bytes = le16_to_cpu(sr->sr_bytes); + + if (bytes == 0 || bytes > sb->s_blocksize) { + ret = NILFS_SEG_FAIL_CHECKSUM_SUPER_ROOT; + goto failed_bh; + } + if (calc_crc_cont(NILFS_SB(sb), 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(ret); +} + +/** + * load_segment_summary - read segment summary of the specified partial segment + * @sbi: nilfs_sb_info + * @pseg_start: start disk block number of partial segment + * @seg_seq: sequence number requested + * @ssi: pointer to nilfs_segsum_info struct to store information + * @full_check: full check flag + * (0: only checks segment summary CRC, 1: data CRC) + */ +static int +load_segment_summary(struct nilfs_sb_info *sbi, sector_t pseg_start, + u64 seg_seq, struct nilfs_segsum_info *ssi, + int full_check) +{ + struct buffer_head *bh_sum; + struct nilfs_segment_summary *sum; + unsigned long offset, nblock; + u64 check_bytes; + u32 crc, crc_sum; + int ret = NILFS_SEG_FAIL_IO; + + bh_sum = sb_bread(sbi->s_super, pseg_start); + if (!bh_sum) + goto out; + + sum = (struct nilfs_segment_summary *)bh_sum->b_data; + + /* Check consistency of segment summary */ + if (le32_to_cpu(sum->ss_magic) != NILFS_SEGSUM_MAGIC) { + ret = NILFS_SEG_FAIL_MAGIC; + goto failed; + } + store_segsum_info(ssi, sum, sbi->s_super->s_blocksize); + if (seg_seq != ssi->seg_seq) { + ret = NILFS_SEG_FAIL_SEQ; + goto failed; + } + if (full_check) { + offset = sizeof(sum->ss_datasum); + check_bytes = + ((u64)ssi->nblocks << sbi->s_super->s_blocksize_bits); + nblock = ssi->nblocks; + crc_sum = le32_to_cpu(sum->ss_datasum); + ret = NILFS_SEG_FAIL_CHECKSUM_FULL; + } else { /* only checks segment summary */ + offset = sizeof(sum->ss_datasum) + sizeof(sum->ss_sumsum); + check_bytes = ssi->sumbytes; + nblock = ssi->nsumblk; + crc_sum = le32_to_cpu(sum->ss_sumsum); + ret = NILFS_SEG_FAIL_CHECKSUM_SEGSUM; + } + + if (unlikely(nblock == 0 || + nblock > sbi->s_nilfs->ns_blocks_per_segment)) { + /* This limits the number of blocks read in the CRC check */ + ret = NILFS_SEG_FAIL_CONSISTENCY; + goto failed; + } + if (calc_crc_cont(sbi, bh_sum, &crc, offset, check_bytes, + pseg_start, nblock)) { + ret = NILFS_SEG_FAIL_IO; + goto failed; + } + if (crc == crc_sum) + ret = 0; + failed: + brelse(bh_sum); + out: + return ret; +} + +static void *segsum_get(struct super_block *sb, 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 = sb_bread(sb, blocknr + 1); + if (unlikely(!*pbh)) + return NULL; + *offset = 0; + } + ptr = (*pbh)->b_data + *offset; + *offset += bytes; + return ptr; +} + +static void segsum_skip(struct super_block *sb, 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 = sb_bread(sb, blocknr + bcnt); + } +} + +static int +collect_blocks_from_segsum(struct nilfs_sb_info *sbi, sector_t sum_blocknr, + struct nilfs_segsum_info *ssi, + struct list_head *head) +{ + struct buffer_head *bh; + unsigned int offset; + unsigned long nfinfo = ssi->nfinfo; + sector_t blocknr = sum_blocknr + ssi->nsumblk; + ino_t ino; + int err = -EIO; + + if (!nfinfo) + return 0; + + bh = sb_bread(sbi->s_super, sum_blocknr); + if (unlikely(!bh)) + goto out; + + offset = le16_to_cpu( + ((struct nilfs_segment_summary *)bh->b_data)->ss_bytes); + for (;;) { + unsigned long nblocks, ndatablk, nnodeblk; + struct nilfs_finfo *finfo; + + finfo = segsum_get(sbi->s_super, &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 = segsum_get(sbi->s_super, &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 the data sync segments */ + segsum_skip(sbi->s_super, &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 + = list_entry(head->next, + struct nilfs_recovery_block, list); + list_del(&rb->list); + kfree(rb); + } +} + +void nilfs_dispose_segment_list(struct list_head *head) +{ + while (!list_empty(head)) { + struct nilfs_segment_entry *ent + = list_entry(head->next, + struct nilfs_segment_entry, list); + list_del(&ent->list); + nilfs_free_segment_entry(ent); + } +} + +static int nilfs_prepare_segment_for_recovery(struct the_nilfs *nilfs, + 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; + + err = -ENOMEM; + for (i = 1; i < 4; i++) { + ent = nilfs_alloc_segment_entry(segnum[i]); + if (unlikely(!ent)) + goto failed; + list_add_tail(&ent->list, head); + } + + /* + * Collecting segments written after the latest super root. + * These are marked volatile active, and won't be reallocated in + * the next construction. + */ + list_for_each_entry_safe(ent, n, head, list) { + if (ent->segnum == segnum[0]) { + list_del(&ent->list); + nilfs_free_segment_entry(ent); + continue; + } + err = nilfs_open_segment_entry(ent, sufile); + if (unlikely(err)) + goto failed; + if (nilfs_segment_usage_clean(ent->raw_su)) { + nilfs_segment_usage_set_volatile_active(ent->raw_su); + /* Keep it open */ + } else { + /* Removing duplicated entries */ + list_del(&ent->list); + nilfs_close_segment_entry(ent, sufile); + nilfs_free_segment_entry(ent); + } + } + list_splice_init(head, nilfs->ns_used_segments.prev); + + /* + * The segment having the latest super root is active, and + * should be deactivated on the next construction for recovery. + */ + err = -ENOMEM; + ent = nilfs_alloc_segment_entry(segnum[0]); + if (unlikely(!ent)) + goto failed; + list_add_tail(&ent->list, &ri->ri_used_segments); + + /* 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]; + return 0; + + failed: + /* No need to recover sufile because it will be destroyed on error */ + return err; +} + +static int nilfs_recovery_copy_block(struct nilfs_sb_info *sbi, + struct nilfs_recovery_block *rb, + struct page *page) +{ + struct buffer_head *bh_org; + void *kaddr; + + bh_org = sb_bread(sbi->s_super, rb->blocknr); + if (unlikely(!bh_org)) + return -EIO; + + kaddr = kmap_atomic(page, KM_USER0); + memcpy(kaddr + bh_offset(bh_org), bh_org->b_data, bh_org->b_size); + kunmap_atomic(kaddr, KM_USER0); + brelse(bh_org); + return 0; +} + +static int recover_dsync_blocks(struct nilfs_sb_info *sbi, + struct list_head *head, + unsigned long *nr_salvaged_blocks) +{ + struct inode *inode; + struct nilfs_recovery_block *rb, *n; + unsigned blocksize = sbi->s_super->s_blocksize; + struct page *page; + loff_t pos; + int err = 0, err2 = 0; + + list_for_each_entry_safe(rb, n, head, list) { + inode = nilfs_iget(sbi->s_super, rb->ino); + if (IS_ERR(inode)) { + err = PTR_ERR(inode); + inode = NULL; + goto failed_inode; + } + + pos = rb->blkoff << inode->i_blkbits; + page = NULL; + err = block_write_begin(NULL, inode->i_mapping, pos, blocksize, + 0, &page, NULL, nilfs_get_block); + if (unlikely(err)) + goto failed_inode; + + err = nilfs_recovery_copy_block(sbi, rb, page); + if (unlikely(err)) + goto failed_page; + + err = nilfs_set_file_dirty(sbi, inode, 1); + if (unlikely(err)) + goto failed_page; + + block_write_end(NULL, inode->i_mapping, pos, blocksize, + blocksize, page, NULL); + + unlock_page(page); + page_cache_release(page); + + (*nr_salvaged_blocks)++; + goto next; + + failed_page: + unlock_page(page); + page_cache_release(page); + + failed_inode: + printk(KERN_WARNING + "NILFS warning: error recovering data block " + "(err=%d, ino=%lu, block-offset=%llu)\n", + err, 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 + * @sbi: nilfs_sb_info + * @nilfs: the_nilfs + * @ri: pointer to a nilfs_recovery_info + */ +static int nilfs_do_roll_forward(struct the_nilfs *nilfs, + struct nilfs_sb_info *sbi, + struct nilfs_recovery_info *ri) +{ + struct nilfs_segsum_info ssi; + sector_t pseg_start; + sector_t seg_start, seg_end; /* Starting/ending DBN of full segment */ + unsigned long nsalvaged_blocks = 0; + 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; + + nilfs_attach_writer(nilfs, sbi); + 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) { + + ret = load_segment_summary(sbi, pseg_start, seg_seq, &ssi, 1); + if (ret) { + if (ret == NILFS_SEG_FAIL_IO) { + err = -EIO; + goto failed; + } + goto strayed; + } + if (unlikely(NILFS_SEG_HAS_SR(&ssi))) + goto confused; + + /* Found a valid partial segment; do recovery actions */ + nextnum = nilfs_get_segnum_of_block(nilfs, ssi.next); + empty_seg = 0; + nilfs->ns_ctime = ssi.ctime; + if (!(ssi.flags & NILFS_SS_GC)) + nilfs->ns_nongc_ctime = ssi.ctime; + + switch (state) { + case RF_INIT_ST: + if (!NILFS_SEG_LOGBGN(&ssi) || !NILFS_SEG_DSYNC(&ssi)) + goto try_next_pseg; + state = RF_DSYNC_ST; + /* Fall through */ + case RF_DSYNC_ST: + if (!NILFS_SEG_DSYNC(&ssi)) + goto confused; + + err = collect_blocks_from_segsum( + sbi, pseg_start, &ssi, &dsync_blocks); + if (unlikely(err)) + goto failed; + if (NILFS_SEG_LOGEND(&ssi)) { + err = recover_dsync_blocks( + sbi, &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 += ssi.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) { + printk(KERN_INFO "NILFS (device %s): salvaged %lu blocks\n", + sbi->s_super->s_id, nsalvaged_blocks); + ri->ri_need_recovery = NILFS_RECOVERY_ROLLFORWARD_DONE; + } + out: + dispose_recovery_list(&dsync_blocks); + nilfs_detach_writer(sbi->s_nilfs, sbi); + return err; + + confused: + err = -EINVAL; + failed: + printk(KERN_ERR + "NILFS (device %s): Error roll-forwarding " + "(err=%d, pseg block=%llu). ", + sbi->s_super->s_id, err, (unsigned long long)pseg_start); + goto out; +} + +static void nilfs_finish_roll_forward(struct the_nilfs *nilfs, + struct nilfs_sb_info *sbi, + 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 = sb_getblk(sbi->s_super, ri->ri_lsegs_start); + BUG_ON(!bh); + memset(bh->b_data, 0, bh->b_size); + set_buffer_dirty(bh); + err = sync_dirty_buffer(bh); + if (unlikely(err)) + printk(KERN_WARNING + "NILFS warning: buffer sync write failed during " + "post-cleaning of recovery.\n"); + brelse(bh); +} + +/** + * nilfs_recover_logical_segments - salvage logical segments written after + * the latest super root + * @nilfs: the_nilfs + * @sbi: nilfs_sb_info + * @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_recover_logical_segments(struct the_nilfs *nilfs, + struct nilfs_sb_info *sbi, + struct nilfs_recovery_info *ri) +{ + int err; + + if (ri->ri_lsegs_start == 0 || ri->ri_lsegs_end == 0) + return 0; + + err = nilfs_attach_checkpoint(sbi, ri->ri_cno); + if (unlikely(err)) { + printk(KERN_ERR + "NILFS: error loading the latest checkpoint.\n"); + return err; + } + + err = nilfs_do_roll_forward(nilfs, sbi, ri); + if (unlikely(err)) + goto failed; + + if (ri->ri_need_recovery == NILFS_RECOVERY_ROLLFORWARD_DONE) { + err = nilfs_prepare_segment_for_recovery(nilfs, ri); + if (unlikely(err)) { + printk(KERN_ERR "NILFS: Error preparing segments for " + "recovery.\n"); + goto failed; + } + + err = nilfs_attach_segment_constructor(sbi, ri); + if (unlikely(err)) + goto failed; + + set_nilfs_discontinued(nilfs); + err = nilfs_construct_segment(sbi->s_super); + nilfs_detach_segment_constructor(sbi); + + if (unlikely(err)) { + printk(KERN_ERR "NILFS: Oops! recovery failed. " + "(err=%d)\n", err); + goto failed; + } + + nilfs_finish_roll_forward(nilfs, sbi, ri); + } + + nilfs_detach_checkpoint(sbi); + return 0; + + failed: + nilfs_detach_checkpoint(sbi); + nilfs_mdt_clear(nilfs->ns_cpfile); + nilfs_mdt_clear(nilfs->ns_sufile); + nilfs_mdt_clear(nilfs->ns_dat); + return err; +} + +/** + * nilfs_search_super_root - search the latest valid super root + * @nilfs: the_nilfs + * @sbi: nilfs_sb_info + * @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 + */ +int nilfs_search_super_root(struct the_nilfs *nilfs, struct nilfs_sb_info *sbi, + struct nilfs_recovery_info *ri) +{ + struct nilfs_segsum_info ssi; + sector_t pseg_start, pseg_end, sr_pseg_start = 0; + sector_t seg_start, seg_end; /* range of full segment (block number) */ + u64 seg_seq; + __u64 segnum, nextnum = 0; + __u64 cno; + struct nilfs_segment_entry *ent; + 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); + + for (;;) { + /* Load segment summary */ + ret = load_segment_summary(sbi, pseg_start, seg_seq, &ssi, 1); + if (ret) { + if (ret == NILFS_SEG_FAIL_IO) + goto failed; + goto strayed; + } + pseg_end = pseg_start + ssi.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, ssi.next); + ri->ri_nextnum = nextnum; + empty_seg = 0; + + if (!NILFS_SEG_HAS_SR(&ssi)) { + if (!scan_newer) { + /* This will never happen because a superblock + (last_segment) always points to a pseg + having a super root. */ + ret = NILFS_SEG_FAIL_CONSISTENCY; + goto failed; + } + if (!ri->ri_lsegs_start && NILFS_SEG_LOGBGN(&ssi)) { + ri->ri_lsegs_start = pseg_start; + ri->ri_lsegs_start_seq = seg_seq; + } + if (NILFS_SEG_LOGEND(&ssi)) + 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); + nilfs->ns_pseg_offset = (sr_pseg_start = pseg_start) + + ssi.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 = ssi.ctime; + 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; + + /* reset region for roll-forward */ + pseg_start += ssi.nblocks; + if (pseg_start < seg_end) + continue; + goto feed_segment; + + try_next_pseg: + /* Standing on a course, or met an inconsistent state */ + pseg_start += ssi.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 */ + + ent = nilfs_alloc_segment_entry(segnum); + if (unlikely(!ent)) { + ret = -ENOMEM; + goto failed; + } + list_add_tail(&ent->list, &segments); + + 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 */ + list_splice(&segments, ri->ri_used_segments.prev); + 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: + nilfs_dispose_segment_list(&segments); + return (ret < 0) ? ret : nilfs_warn_segment_error(ret); +} |