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| author | Darrick J. Wong <darrick.wong@oracle.com> | 2017-06-23 00:58:57 -0400 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2017-06-23 00:58:57 -0400 |
| commit | 4a4956249dac0b9b0027949907bff0cd1a9b57fa (patch) | |
| tree | 21a8a934c009172ce55d29c97679462dbf2986e2 /fs/ext4 | |
| parent | bdddf342796765a1a946e7c4aed2574f4488e4e5 (diff) | |
| download | linux-4a4956249dac0b9b0027949907bff0cd1a9b57fa.tar.bz2 | |
ext4: fix off-by-one fsmap error on 1k block filesystems
For 1k-block filesystems, the filesystem starts at block 1, not block 0.
This fact is recorded in s_first_data_block, so use that to bump up the
start_fsb before we start querying the filesystem for its space map.
Without this, ext4/026 fails on 1k block ext4 because various functions
(notably ext4_get_group_no_and_offset) don't know what to do with an
fsblock that is "before" the start of the filesystem and return garbage
results (blockgroup 2^32-1, etc.) that confuse fsmap.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Diffstat (limited to 'fs/ext4')
| -rw-r--r-- | fs/ext4/fsmap.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/fs/ext4/fsmap.c b/fs/ext4/fsmap.c index b19436098837..7ec340898598 100644 --- a/fs/ext4/fsmap.c +++ b/fs/ext4/fsmap.c @@ -480,6 +480,7 @@ static int ext4_getfsmap_datadev(struct super_block *sb, struct ext4_sb_info *sbi = EXT4_SB(sb); ext4_fsblk_t start_fsb; ext4_fsblk_t end_fsb; + ext4_fsblk_t bofs; ext4_fsblk_t eofs; ext4_group_t start_ag; ext4_group_t end_ag; @@ -487,9 +488,12 @@ static int ext4_getfsmap_datadev(struct super_block *sb, ext4_grpblk_t last_cluster; int error = 0; + bofs = le32_to_cpu(sbi->s_es->s_first_data_block); eofs = ext4_blocks_count(sbi->s_es); if (keys[0].fmr_physical >= eofs) return 0; + else if (keys[0].fmr_physical < bofs) + keys[0].fmr_physical = bofs; if (keys[1].fmr_physical >= eofs) keys[1].fmr_physical = eofs - 1; start_fsb = keys[0].fmr_physical; |