2009-02-18 22:32:10

by Greg KH

[permalink] [raw]
Subject: [patch 19/36] ext4: Dont overwrite allocation_context ac_status

2.6.27-stable review patch. If anyone has any objections, please let us know.


From: Aneesh Kumar K.V <[email protected]>

(cherry picked from commit 032115fcef837a00336ddf7bda584e89789ea498)

We can call ext4_mb_check_limits even after successfully allocating
the requested blocks. In that case, make sure we don't overwrite
ac_status if it already has the status AC_STATUS_FOUND. This fixes
the lockdep warning:

[ INFO: possible recursive locking detected ]
2.6.28-rc6-autokern1 #1
fsstress/11948 is trying to acquire lock:
(&meta_group_info[i]->alloc_sem){----}, at: [<c04d9a49>] ext4_mb_load_buddy+0x9f/0x278

stack backtrace:
[<c04db974>] ext4_mb_regular_allocator+0xbb5/0xd44

but task is already holding lock:
(&meta_group_info[i]->alloc_sem){----}, at: [<c04d9a49>] ext4_mb_load_buddy+0x9f/0x278

Signed-off-by: Aneesh Kumar K.V <[email protected]>
Signed-off-by: "Theodore Ts'o" <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

fs/ext4/mballoc.c | 2 ++
1 file changed, 2 insertions(+)

--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -1326,6 +1326,8 @@ static void ext4_mb_check_limits(struct
struct ext4_free_extent ex;
int max;

+ if (ac->ac_status == AC_STATUS_FOUND)
+ return;
* We don't want to scan for a whole year