Patch "btrfs: Explicitly handle btrfs_update_root failure" has been added to the 4.14-stable tree

This is a note to let you know that I've just added the patch titled

btrfs: Explicitly handle btrfs_update_root failure

to the 4.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
btrfs-explicitly-handle-btrfs_update_root-failure.patch
and it can be found in the queue-4.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Nikolay Borisov <[email protected]>
Date: Thu, 28 Sep 2017 10:53:17 +0300
Subject: btrfs: Explicitly handle btrfs_update_root failure

From: Nikolay Borisov <[email protected]>

[ Upstream commit 9417ebc8a676487c6ec8825f92fb28f7dbeb5f4b ]

btrfs_udpate_root can fail and it aborts the transaction, the correct way to handle an aborted transaction is to explicitly end with btrfs_end_transaction. Even now the code is correct since btrfs_commit_transaction would handle an aborted transaction but this is more of an implementation detail. So let's be explicit in handling failure in btrfs_update_root.

Furthermore btrfs_commit_transaction can also fail and by ignoring it's return value we could have left the in-memory copy of the root item in an inconsistent state. So capture the error value which allows us to correctly revert the RO/RW flags in case of commit failure.

---
 fs/btrfs/ioctl.c |    7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

@@ -1842,8 +1842,13 @@ static noinline int btrfs_ioctl_subvol_s
 
 	ret = btrfs_update_root(trans, fs_info->tree_root,
 				&root->root_key, &root->root_item);
+	if (ret < 0) {
+		btrfs_end_transaction(trans);
+		goto out_reset;
+	}
+
+	ret = btrfs_commit_transaction(trans);
 
-	btrfs_commit_transaction(trans);
 out_reset:
 	if (ret)
 		btrfs_set_root_flags(&root->root_item, root_flags);

Patches currently in stable-queue which might be from [email protected] are

queue-4.14/btrfs-explicitly-handle-btrfs_update_root-failure.patch queue-4.14/btrfs-undo-writable-superblocke-when-sprouting-fails.patch