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authorDarrick J. Wong <darrick.wong@oracle.com>2017-06-23 00:58:57 -0400
committerTheodore Ts'o <tytso@mit.edu>2017-06-23 00:58:57 -0400
commit4a4956249dac0b9b0027949907bff0cd1a9b57fa (patch)
tree21a8a934c009172ce55d29c97679462dbf2986e2 /fs/ext4/fsmap.c
parentbdddf342796765a1a946e7c4aed2574f4488e4e5 (diff)
downloadlinux-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/fsmap.c')
-rw-r--r--fs/ext4/fsmap.c4
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;