Commit 4a495624 authored by Darrick J. Wong's avatar Darrick J. Wong Committed by Theodore Ts'o

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: default avatarDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
parent bdddf342
...@@ -480,6 +480,7 @@ static int ext4_getfsmap_datadev(struct super_block *sb, ...@@ -480,6 +480,7 @@ static int ext4_getfsmap_datadev(struct super_block *sb,
struct ext4_sb_info *sbi = EXT4_SB(sb); struct ext4_sb_info *sbi = EXT4_SB(sb);
ext4_fsblk_t start_fsb; ext4_fsblk_t start_fsb;
ext4_fsblk_t end_fsb; ext4_fsblk_t end_fsb;
ext4_fsblk_t bofs;
ext4_fsblk_t eofs; ext4_fsblk_t eofs;
ext4_group_t start_ag; ext4_group_t start_ag;
ext4_group_t end_ag; ext4_group_t end_ag;
...@@ -487,9 +488,12 @@ static int ext4_getfsmap_datadev(struct super_block *sb, ...@@ -487,9 +488,12 @@ static int ext4_getfsmap_datadev(struct super_block *sb,
ext4_grpblk_t last_cluster; ext4_grpblk_t last_cluster;
int error = 0; int error = 0;
bofs = le32_to_cpu(sbi->s_es->s_first_data_block);
eofs = ext4_blocks_count(sbi->s_es); eofs = ext4_blocks_count(sbi->s_es);
if (keys[0].fmr_physical >= eofs) if (keys[0].fmr_physical >= eofs)
return 0; return 0;
else if (keys[0].fmr_physical < bofs)
keys[0].fmr_physical = bofs;
if (keys[1].fmr_physical >= eofs) if (keys[1].fmr_physical >= eofs)
keys[1].fmr_physical = eofs - 1; keys[1].fmr_physical = eofs - 1;
start_fsb = keys[0].fmr_physical; start_fsb = keys[0].fmr_physical;
......
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