[PATCH 3.12 042/181] xfs: fix the extent count when allocating an new indirection array entry

Jiri Slaby
2014-06-30T12:08:39Z

From: Jie Liu <jeff.liu@oracle.com>

3.12-stable review patch. If anyone has any objections, please let me know.

===============

commit bb86d21cba22a045b09d11b71decf5ca7c3d5def upstream.

At xfs_iext_add(), if extent(s) are being appended to the last page in
the indirection array and the new extent(s) don't fit in the page, the
number of extents(erp->er_extcount) in a new allocated entry should be
the minimum value between count and XFS_LINEAR_EXTS, instead of count.

For now, there is no existing test case can demonstrates a problem with
the er_extcount being set incorrectly here, but it obviously like a bug.

Signed-off-by: Jie Liu <jeff.liu@oracle.com>
Reviewed-by: Ben Myers <bpm@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
fs/xfs/xfs_inode_fork.c | 9 ++++-----
1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/fs/xfs/xfs_inode_fork.c b/fs/xfs/xfs_inode_fork.c
index 4fa56fcb38d1..6829134de253 100644
--- a/fs/xfs/xfs_inode_fork.c
+++ b/fs/xfs/xfs_inode_fork.c
@@ -1031,15 +1031,14 @@ xfs_iext_add(
* the next index needed in the indirection array.
*/
else {
- int count = ext_diff;
+ uint count = ext_diff;

while (count) {
erp = xfs_iext_irec_new(ifp, erp_idx);
- erp->er_extcount = count;
- count -= MIN(count, (int)XFS_LINEAR_EXTS);
- if (count) {
+ erp->er_extcount = min(count, XFS_LINEAR_EXTS);
+ count -= erp->er_extcount;
+ if (count)
erp_idx++;
- }
}
}
}
--
2.0.0