The patch below does not apply to the 6.15-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-6.15.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-mothproof-embody-49e3@gregkh' --subject-prefix 'PATCH 6.15.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)