FAILED: patch "[PATCH] btrfs: abort transaction on unexpected eb generation at" failed to apply to 6.12-stable tree

[<gregkh@linuxfoundation.org>]

The patch below does not apply to the 6.12-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@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.12.y
git checkout FETCH_HEAD
git cherry-pick -x 33e8f24b52d2796b8cfb28c19a1a7dd6476323a8
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2025081815-strut-suspend-7a53@gregkh' --subject-prefix 'PATCH 6.12.y' HEAD^..

Possible dependencies:



thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 33e8f24b52d2796b8cfb28c19a1a7dd6476323a8 Mon Sep 17 00:00:00 2001
From: Filipe Manana <fdmanana@suse.com>
Date: Mon, 19 May 2025 11:07:29 +0100
Subject: [PATCH] btrfs: abort transaction on unexpected eb generation at
 btrfs_copy_root()

If we find an unexpected generation for the extent buffer we are cloning
at btrfs_copy_root(), we just WARN_ON() and don't error out and abort the
transaction, meaning we allow to persist metadata with an unexpected
generation. Instead of warning only, abort the transaction and return
-EUCLEAN.

CC: stable@vger.kernel.org # 6.1+
Reviewed-by: Daniel Vacek <neelx@suse.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index ae6cd77282f5..a5ee6ce312cf 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -283,7 +283,14 @@ int btrfs_copy_root(struct btrfs_trans_handle *trans,
 
 	write_extent_buffer_fsid(cow, fs_info->fs_devices->metadata_uuid);
 
-	WARN_ON(btrfs_header_generation(buf) > trans->transid);
+	if (unlikely(btrfs_header_generation(buf) > trans->transid)) {
+		btrfs_tree_unlock(cow);
+		free_extent_buffer(cow);
+		ret = -EUCLEAN;
+		btrfs_abort_transaction(trans, ret);
+		return ret;
+	}
+
 	if (new_root_objectid == BTRFS_TREE_RELOC_OBJECTID) {
 		ret = btrfs_inc_ref(trans, root, cow, 1);
 		if (ret)