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authorAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>2008-11-23 23:51:53 -0500
committerTheodore Ts'o <tytso@mit.edu>2008-11-23 23:51:53 -0500
commitb7be019e80da4db96d283734d55366014509911c (patch)
tree86304f0c872dad5200e6015b7e7b56e53ad61ba8 /fs/ext4/mballoc.c
parent7a2fcbf7f85737735fd44eb34b62315bccf6d6e4 (diff)
downloadblackbird-op-linux-b7be019e80da4db96d283734d55366014509911c.tar.gz
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ext4: Fix lockdep recursive locking warning
In ext4_mb_init_group(), if the filesystem block size is less than PAGE_SIZE/2, the code tries to grab alloc_sem for multiple block groups in a loop. We need to allow for this by using down_write_nested() and passing in the loop index as a lock subclass number. This works because no other code path needs to take multiple alloc_sem's. Note that lockdep will fail for filesystem blocksize smaller than to PAGE_SIZE/16k. (e.g., a 1k filesystem blocksize with a 32k page size, or a 2k filesystem blocksize with a 64k blocksize, etc.) Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Diffstat (limited to 'fs/ext4/mballoc.c')
-rw-r--r--fs/ext4/mballoc.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 860766421fe8..0bf4c4c06b19 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -1780,7 +1780,7 @@ int ext4_mb_get_buddy_cache_lock(struct super_block *sb, ext4_group_t group)
* no block allocation going on in any
* of that groups
*/
- down_write(&grp->alloc_sem);
+ down_write_nested(&grp->alloc_sem, i);
}
return i;
}
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