| | Date | Wed, 11 Aug 2010 16:54:55 -0700 | | From | Greg KH <> | | Subject | [074/111] Btrfs: fix race between allocate and release extent buffer. |
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2.6.32-stable review patch. If anyone has any objections, please let us know.
------------------ From: Yan, Zheng <zheng.yan@oracle.com>
commit f044ba7835b84e69c68b620ca8fa27e5ef67759d upstream.
Increase extent buffer's reference count while holding the lock. Otherwise it can race with try_release_extent_buffer.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com> Signed-off-by: Chris Mason <chris.mason@oracle.com> Acked-by: Jeff Mahoney <jeffm@suse.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
--- fs/btrfs/extent_io.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) --- a/fs/btrfs/extent_io.c +++ b/fs/btrfs/extent_io.c @@ -3165,10 +3165,9 @@ struct extent_buffer *alloc_extent_buffe spin_unlock(&tree->buffer_lock); goto free_eb; } - spin_unlock(&tree->buffer_lock); - /* add one reference for the tree */ atomic_inc(&eb->refs); + spin_unlock(&tree->buffer_lock); return eb; free_eb:
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