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authorBrian Foster <bfoster@redhat.com>2014-08-04 11:35:35 +1000
committerDave Chinner <david@fromorbit.com>2014-08-04 11:35:35 +1000
commiteedf32bfcace7d8e20cc66757d74fc68f3439ff7 (patch)
treee6e719201cbdb4b2ce72cc6d93e06fe14c604b07 /fs/xfs
parent2451337dd043901b5270b7586942abe564443e3d (diff)
xfs: fix rounding error of fiemap length parameter
The offset and length parameters are converted from bytes to basic blocks by xfs_vn_fiemap(). The BTOBB() converter rounds the value up to the nearest basic block. This leads to unexpected behavior when unaligned offsets are provided to FIEMAP. Fix the conversions of byte values to block values to cover the provided offsets. Round down the start offset to the nearest basic block. Calculate the end offset based on the provided values, round up and calculate length based on the start block offset. Reported-by: Chandan Rajendra <chandan@linux.vnet.ibm.com> Signed-off-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
Diffstat (limited to 'fs/xfs')
-rw-r--r--fs/xfs/xfs_iops.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c
index d75621ae3e36..72129493e9d3 100644
--- a/fs/xfs/xfs_iops.c
+++ b/fs/xfs/xfs_iops.c
@@ -1055,12 +1055,12 @@ xfs_vn_fiemap(
return error;
/* Set up bmap header for xfs internal routine */
- bm.bmv_offset = BTOBB(start);
+ bm.bmv_offset = BTOBBT(start);
/* Special case for whole file */
if (length == FIEMAP_MAX_OFFSET)
bm.bmv_length = -1LL;
else
- bm.bmv_length = BTOBB(length);
+ bm.bmv_length = BTOBB(start + length) - bm.bmv_offset;
/* We add one because in getbmap world count includes the header */
bm.bmv_count = !fieinfo->fi_extents_max ? MAXEXTNUM :