diff options
authorSage Weil <>2010-05-17 17:15:27 +0000
committerChris Mason <>2010-06-11 15:57:39 -0400
commit15e7000095e6fc9ad07e476a100c900c72c14225 (patch)
parent731e3d1b4348a96d53de6c084774424dedc64a3b (diff)
Btrfs: avoid BUG when dropping root and reference in same transaction
If btrfs_ioctl_snap_destroy() deletes a snapshot but finishes with end_transaction(), the cleaner kthread may come in and drop the root in the same transaction. If that's the case, the root's refs still == 1 in the tree when btrfs_del_root() deletes the item, because commit_fs_roots() hasn't updated it yet (that happens during the commit). This wasn't a problem before only because btrfs_ioctl_snap_destroy() would commit the transaction before dropping the dentry reference, so the dead root wouldn't get queued up until after the fs root item was updated in the btree. Since it is not an error to drop the root reference and the root in the same transaction, just drop the BUG_ON() in btrfs_del_root(). Signed-off-by: Sage Weil <> Signed-off-by: Chris Mason <>
1 files changed, 0 insertions, 3 deletions
diff --git a/fs/btrfs/root-tree.c b/fs/btrfs/root-tree.c
index b91ccd972644..2d958be761c8 100644
--- a/fs/btrfs/root-tree.c
+++ b/fs/btrfs/root-tree.c
@@ -330,7 +330,6 @@ int btrfs_del_root(struct btrfs_trans_handle *trans, struct btrfs_root *root,
struct btrfs_path *path;
int ret;
- u32 refs;
struct btrfs_root_item *ri;
struct extent_buffer *leaf;
@@ -344,8 +343,6 @@ int btrfs_del_root(struct btrfs_trans_handle *trans, struct btrfs_root *root,
leaf = path->nodes[0];
ri = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_item);
- refs = btrfs_disk_root_refs(leaf, ri);
- BUG_ON(refs != 0);
ret = btrfs_del_item(trans, root, path);