Btrfs: fix nocow when deleting the item
btrfs_previous_item() just search the b+ tree, do not COW the nodes or leaves,
if we modify the result of it, the meta-data will be broken. fix it.
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index f8e29431..c37433d 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -999,7 +999,7 @@
key.objectid = device->devid;
key.offset = start;
key.type = BTRFS_DEV_EXTENT_KEY;
-
+again:
ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
if (ret > 0) {
ret = btrfs_previous_item(root, path, key.objectid,
@@ -1012,6 +1012,9 @@
struct btrfs_dev_extent);
BUG_ON(found_key.offset > start || found_key.offset +
btrfs_dev_extent_length(leaf, extent) < start);
+ key = found_key;
+ btrfs_release_path(path);
+ goto again;
} else if (ret == 0) {
leaf = path->nodes[0];
extent = btrfs_item_ptr(leaf, path->slots[0],
