The patch below does not apply to the 4.9-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@xxxxxxxxxxxxxxx>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From 1402d17dfd9657be0da8458b2079d03c2d61c86a Mon Sep 17 00:00:00 2001
From: Xiyu Yang <xiyuyang19@xxxxxxxxxxxx>
Date: Mon, 20 Apr 2020 13:39:39 +0800
Subject: [PATCH] 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: 79787eaab461 ("btrfs: replace many BUG_ONs with proper error handling")
CC: stable@xxxxxxxxxxxxxxx # 4.4+
Reviewed-by: Filipe Manana <fdmanana@xxxxxxxx>
Signed-off-by: Xiyu Yang <xiyuyang19@xxxxxxxxxxxx>
Signed-off-by: Xin Tan <tanxin.ctf@xxxxxxxxx>
Signed-off-by: David Sterba <dsterba@xxxxxxxx>
diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index d35936c934ab..03bc7134e8cb 100644
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -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;
}
