btrfs: abort in rename_exchange if we fail to insert the second ref

stable inclusion
from stable-5.10.43
commit 0df50d47d17401f9f140dfbe752a65e5d72f9932
bugzilla: 109284
CVE: NA

--------------------------------

commit dc09ef35 upstream.

Error injection stress uncovered a problem where we'd leave a dangling
inode ref if we failed during a rename_exchange.  This happens because
we insert the inode ref for one side of the rename, and then for the
other side.  If this second inode ref insert fails we'll leave the first
one dangling and leave a corrupt file system behind.  Fix this by
aborting if we did the insert for the first inode ref.

CC: stable@vger.kernel.org # 4.9+
Signed-off-by: NJosef Bacik <josef@toxicpanda.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NChen Jun <chenjun102@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

fs/btrfs/inode.c

@@ -8890,6 +8890,7 @@ static int btrfs_rename_exchange(struct inode *old_dir,
 	int ret2;
 	bool root_log_pinned = false;
 	bool dest_log_pinned = false;
+	bool need_abort = false;
 
 	/* we only allow rename subvolume link between subvolumes */
 	if (old_ino != BTRFS_FIRST_FREE_OBJECTID && root != dest)
@@ -8946,6 +8947,7 @@ static int btrfs_rename_exchange(struct inode *old_dir,
 					     old_idx);
 		if (ret)
 			goto out_fail;
+		need_abort = true;
 	}
 
 	/* And now for the dest. */
@@ -8961,9 +8963,12 @@ static int btrfs_rename_exchange(struct inode *old_dir,
 					     new_ino,
 					     btrfs_ino(BTRFS_I(old_dir)),
 					     new_idx);
-		if (ret)
+		if (ret) {
+			if (need_abort)
+				btrfs_abort_transaction(trans, ret);
 			goto out_fail;
 		}
+	}
 
 	/* Update inode version and ctime/mtime. */
 	inode_inc_iversion(old_dir);