Btrfs: use join_transaction in btrfs_evict_inode()

The WARN_ON() in start_transaction() was triggered while balancing.

The cause is btrfs_relocate_chunk() started a transaction and
then called iput() on the inode that stores free space cache,
and iput() called btrfs_start_transaction() again.

Reported-by: Tsutomu Itoh <t-itoh@jp.fujitsu.com>
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Reviewed-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 113913ae36e0..c15636b17874 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -3646,7 +3646,7 @@ void btrfs_evict_inode(struct inode *inode)
         btrfs_i_size_write(inode, 0);
 
         while (1) {
-                trans = btrfs_start_transaction(root, 0);
+                trans = btrfs_join_transaction(root);
                 BUG_ON(IS_ERR(trans));
                 trans->block_rsv = root->orphan_block_rsv;