Josef Bacik
2013-Jul-15 16:43 UTC
[PATCH] Btrfs: fix lock leak when resuming snapshot deletion
We aren''t setting path->locks[level] when we resume a snapshot
deletion which
means we won''t unlock the buffer when we free the path. This causes
deadlocks
if we happen to re-allocate the block before we''ve evicted the extent
buffer
from cache. Thanks,
Reported-by: Alex Lyakas <alex.btrfs@zadarastorage.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
---
fs/btrfs/extent-tree.c | 2 ++
1 files changed, 2 insertions(+), 0 deletions(-)
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 8c204e1..997a5dd 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -7555,6 +7555,7 @@ int btrfs_drop_snapshot(struct btrfs_root *root,
while (1) {
btrfs_tree_lock(path->nodes[level]);
btrfs_set_lock_blocking(path->nodes[level]);
+ path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
ret = btrfs_lookup_extent_info(trans, root,
path->nodes[level]->start,
@@ -7570,6 +7571,7 @@ int btrfs_drop_snapshot(struct btrfs_root *root,
break;
btrfs_tree_unlock(path->nodes[level]);
+ path->locks[level] = 0;
WARN_ON(wc->refs[level] != 1);
level--;
}
--
1.7.7.6
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Alex Lyakas
2013-Jul-16 14:54 UTC
Re: [PATCH] Btrfs: fix lock leak when resuming snapshot deletion
On Mon, Jul 15, 2013 at 7:43 PM, Josef Bacik <jbacik@fusionio.com> wrote:> We aren''t setting path->locks[level] when we resume a snapshot deletion which > means we won''t unlock the buffer when we free the path. This causes deadlocks > if we happen to re-allocate the block before we''ve evicted the extent buffer > from cache. Thanks, > > Reported-by: Alex Lyakas <alex.btrfs@zadarastorage.com> > Signed-off-by: Josef Bacik <jbacik@fusionio.com> > --- > fs/btrfs/extent-tree.c | 2 ++ > 1 files changed, 2 insertions(+), 0 deletions(-) > > diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c > index 8c204e1..997a5dd 100644 > --- a/fs/btrfs/extent-tree.c > +++ b/fs/btrfs/extent-tree.c > @@ -7555,6 +7555,7 @@ int btrfs_drop_snapshot(struct btrfs_root *root, > while (1) { > btrfs_tree_lock(path->nodes[level]); > btrfs_set_lock_blocking(path->nodes[level]); > + path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING; > > ret = btrfs_lookup_extent_info(trans, root, > path->nodes[level]->start, > @@ -7570,6 +7571,7 @@ int btrfs_drop_snapshot(struct btrfs_root *root, > break; > > btrfs_tree_unlock(path->nodes[level]); > + path->locks[level] = 0; > WARN_ON(wc->refs[level] != 1); > level--; > } > -- > 1.7.7.6 > > --Tested-by: Liran Strugano <liran@zadarastorage.com>> To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html-- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html