From 354fa8be280ce81c88b6b236d62d23ebcade2d3f Mon Sep 17 00:00:00 2001 From: Ryusuke Konishi Date: Sun, 23 May 2010 19:21:49 +0900 Subject: [PATCH] nilfs2: divide load_segment_summary function load_segment_summary function has two distinct roles: getting summary header of a log, and verifying consistencies of the log. This divide it into two corresponding functions, nilfs_read_log_header and nilfs_validate_log to clarify the meaning. Signed-off-by: Ryusuke Konishi --- fs/nilfs2/recovery.c | 110 +++++++++++++++++++++++++++---------------- 1 file changed, 69 insertions(+), 41 deletions(-) diff --git a/fs/nilfs2/recovery.c b/fs/nilfs2/recovery.c index fd7fb4149aa7..35506b1704d1 100644 --- a/fs/nilfs2/recovery.c +++ b/fs/nilfs2/recovery.c @@ -202,58 +202,63 @@ int nilfs_read_super_root_block(struct the_nilfs *nilfs, sector_t sr_block, } /** - * load_segment_summary - read segment summary of the specified partial segment + * nilfs_read_log_header - read summary header of the specified log * @nilfs: nilfs object - * @pseg_start: start disk block number of partial segment - * @seg_seq: sequence number requested - * @ssi: pointer to nilfs_segsum_info struct to store information + * @start_blocknr: start block number of the log + * @sum: pointer to return segment summary structure */ -static int -load_segment_summary(struct the_nilfs *nilfs, sector_t pseg_start, - u64 seg_seq, struct nilfs_segsum_info *ssi) +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; - struct nilfs_segment_summary *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 = NILFS_SEG_FAIL_IO; + int ret; - bh_sum = __bread(nilfs->ns_bdev, pseg_start, nilfs->ns_blocksize); - if (!bh_sum) + ret = NILFS_SEG_FAIL_MAGIC; + if (le32_to_cpu(sum->ss_magic) != NILFS_SEGSUM_MAGIC) goto out; - sum = (struct nilfs_segment_summary *)bh_sum->b_data; + ret = NILFS_SEG_FAIL_SEQ; + if (le64_to_cpu(sum->ss_seq) != seg_seq) + goto out; - /* 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, nilfs->ns_blocksize); - if (seg_seq != ssi->seg_seq) { - ret = NILFS_SEG_FAIL_SEQ; - goto failed; - } - - nblock = ssi->nblocks; - if (unlikely(nblock == 0 || nblock > nilfs->ns_blocks_per_segment)) { + 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 */ - ret = NILFS_SEG_FAIL_CONSISTENCY; - goto failed; - } + 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), - pseg_start, nblock)) { - ret = NILFS_SEG_FAIL_IO; - goto failed; - } - if (crc == le32_to_cpu(sum->ss_datasum)) - ret = 0; - else - ret = NILFS_SEG_FAIL_CHECKSUM_FULL; - failed: - brelse(bh_sum); - out: + 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; } @@ -589,6 +594,8 @@ static int nilfs_do_roll_forward(struct the_nilfs *nilfs, struct nilfs_recovery_info *ri) { struct nilfs_segsum_info ssi; + struct buffer_head *bh_sum = NULL; + struct nilfs_segment_summary *sum; sector_t pseg_start; sector_t seg_start, seg_end; /* Starting/ending DBN of full segment */ unsigned long nsalvaged_blocks = 0; @@ -610,8 +617,14 @@ static int nilfs_do_roll_forward(struct the_nilfs *nilfs, 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 = load_segment_summary(nilfs, pseg_start, seg_seq, &ssi); + ret = nilfs_validate_log(nilfs, seg_seq, bh_sum, sum); if (ret) { if (ret == NILFS_SEG_FAIL_IO) { err = -EIO; @@ -619,6 +632,8 @@ static int nilfs_do_roll_forward(struct the_nilfs *nilfs, } goto strayed; } + + store_segsum_info(&ssi, sum, nilfs->ns_blocksize); if (unlikely(NILFS_SEG_HAS_SR(&ssi))) goto confused; @@ -682,6 +697,7 @@ static int nilfs_do_roll_forward(struct the_nilfs *nilfs, ri->ri_need_recovery = NILFS_RECOVERY_ROLLFORWARD_DONE; } out: + brelse(bh_sum); dispose_recovery_list(&dsync_blocks); nilfs_detach_writer(nilfs, sbi); return err; @@ -807,6 +823,8 @@ int nilfs_search_super_root(struct the_nilfs *nilfs, struct nilfs_recovery_info *ri) { struct nilfs_segsum_info ssi; + struct buffer_head *bh_sum = NULL; + struct nilfs_segment_summary *sum; 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; @@ -831,12 +849,20 @@ int nilfs_search_super_root(struct the_nilfs *nilfs, __breadahead(nilfs->ns_bdev, b++, nilfs->ns_blocksize); for (;;) { - ret = load_segment_summary(nilfs, pseg_start, seg_seq, &ssi); + 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; } + + store_segsum_info(&ssi, sum, nilfs->ns_blocksize); pseg_end = pseg_start + ssi.nblocks - 1; if (unlikely(pseg_end > seg_end)) { ret = NILFS_SEG_FAIL_CONSISTENCY; @@ -936,6 +962,7 @@ int nilfs_search_super_root(struct the_nilfs *nilfs, 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; @@ -943,6 +970,7 @@ int nilfs_search_super_root(struct the_nilfs *nilfs, return 0; failed: + brelse(bh_sum); nilfs_dispose_segment_list(&segments); return (ret < 0) ? ret : nilfs_warn_segment_error(ret); }