btrfs: fix transaction leak in btrfs_recover_relocation

btrfs_recover_relocation() invokes btrfs_join_transaction(), which joins
a btrfs_trans_handle object into transactions and returns a reference of
it with increased refcount to "trans".

When btrfs_recover_relocation() returns, "trans" becomes invalid, so the
refcount should be decreased to keep refcount balanced.

The reference counting issue happens in one exception handling path of
btrfs_recover_relocation(). When read_fs_root() failed, the refcnt
increased by btrfs_join_transaction() is not decreased, causing a refcnt
leak.

Fix this issue by calling btrfs_end_transaction() on this error path
when read_fs_root() failed.

Fixes: 79787eaab4 ("btrfs: replace many BUG_ONs with proper error handling")
CC: stable@vger.kernel.org # 4.4+
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Xiyu Yang <xiyuyang19@fudan.edu.cn>
Signed-off-by: Xin Tan <tanxin.ctf@gmail.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Xiyu Yang 2020-04-20 13:39:39 +08:00 committed by David Sterba
parent f6033c5e33
commit 1402d17dfd

View file

@ -4559,6 +4559,7 @@ int btrfs_recover_relocation(struct btrfs_root *root)
if (IS_ERR(fs_root)) {
err = PTR_ERR(fs_root);
list_add_tail(&reloc_root->root_list, &reloc_roots);
btrfs_end_transaction(trans);
goto out_unset;
}