From 48475471728f060bfd2e686f592ef208d3ba8b7d Mon Sep 17 00:00:00 2001 From: Stefan Behrens Date: Fri, 23 Aug 2013 10:34:42 +0200 Subject: [PATCH] Btrfs: fix for patch "cleanup: don't check the same thing twice" Mitch Harder noticed that the patch 3c64a1a mentioned in the subject line was causing a kernel BUG() on snapshot deletion. The patch was wrong. It did not handle cached roots correctly. The check for root_refs == 0 was removed everywhere where btrfs_read_fs_root_no_name() had been used to retrieve the root, because this check was already dealt with in btrfs_read_fs_root_no_name(). But in the case when the root was found in the cache, there was no such check. This patch adds the missing check in the case where the root is found in the cache. Reported-by: Mitch Harder Signed-off-by: Stefan Behrens Reviewed-by: Miao Xie Signed-off-by: Josef Bacik Signed-off-by: Chris Mason --- fs/btrfs/disk-io.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index 0f75a01f69e2..21d1d066758e 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -1584,8 +1584,11 @@ struct btrfs_root *btrfs_read_fs_root_no_name(struct btrfs_fs_info *fs_info, ERR_PTR(-ENOENT); again: root = btrfs_lookup_fs_root(fs_info, location->objectid); - if (root) + if (root) { + if (btrfs_root_refs(&root->root_item) == 0) + return ERR_PTR(-ENOENT); return root; + } root = btrfs_read_fs_root(fs_info->tree_root, location); if (IS_ERR(root)) -- GitLab