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authorChris Mason <chris.mason@oracle.com>2008-11-17 21:14:24 -0500
committerChris Mason <chris.mason@oracle.com>2008-11-17 21:14:24 -0500
commitea9e8b11bd1252dcbc23afefcf1a52ec6aa3c113 (patch)
tree3573c8d79e1936e8c921a3be77abda35124e0d78 /fs/btrfs/root-tree.c
parent0660b5af3f7ac0fac69de975914e1f4a3a586fb3 (diff)
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Btrfs: prevent loops in the directory tree when creating snapshots
For a directory tree: /mnt/subvolA/subvolB btrfsctl -s /mnt/subvolA/subvolB /mnt Will create a directory loop with subvolA under subvolB. This commit uses the forward refs for each subvol and snapshot to error out before creating the loop. Signed-off-by: Chris Mason <chris.mason@oracle.com>
Diffstat (limited to 'fs/btrfs/root-tree.c')
-rw-r--r--fs/btrfs/root-tree.c16
1 files changed, 16 insertions, 0 deletions
diff --git a/fs/btrfs/root-tree.c b/fs/btrfs/root-tree.c
index e9be3abcb36..dbe20d4c6ea 100644
--- a/fs/btrfs/root-tree.c
+++ b/fs/btrfs/root-tree.c
@@ -300,6 +300,22 @@ int btrfs_del_root_ref(struct btrfs_trans_handle *trans,
return ret;
}
+int btrfs_find_root_ref(struct btrfs_root *tree_root,
+ struct btrfs_path *path,
+ u64 root_id, u64 ref_id)
+{
+ struct btrfs_key key;
+ int ret;
+
+ key.objectid = root_id;
+ key.type = BTRFS_ROOT_REF_KEY;
+ key.offset = ref_id;
+
+ ret = btrfs_search_slot(NULL, tree_root, &key, path, 0, 0);
+ return ret;
+}
+
+
/*
* add a btrfs_root_ref item. type is either BTRFS_ROOT_REF_KEY
* or BTRFS_ROOT_BACKREF_KEY.