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@xxxxxxxxxx> --- fs/ext4/fsmap.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/fs/ext4/fsmap.c b/fs/ext4/fsmap.c index b194360..7ec3408 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;
