[PATCH 6.4 765/800] btrfs: do not BUG_ON() on tree mod log failure at __btrfs_cow_block()

Greg Kroah-Hartman
2023-07-16T20:28:36Z

From: Filipe Manana <fdmanana@suse.com>

commit 40b0a749388517de244643c09bdbb98f7dcb6ef1 upstream.

At __btrfs_cow_block(), instead of doing a BUG_ON() in case we fail to
record a tree mod log root insertion operation, do a transaction abort
instead. There's really no need for the BUG_ON(), we can properly
release all resources in this context and turn the filesystem to RO mode
and in an error state instead.

CC: stable@vger.kernel.org # 5.4+
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
fs/btrfs/ctree.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)

--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -583,9 +583,14 @@ static noinline int __btrfs_cow_block(st
btrfs_header_backref_rev(buf) < BTRFS_MIXED_BACKREF_REV)
parent_start = buf->start;

- atomic_inc(&cow->refs);
ret = btrfs_tree_mod_log_insert_root(root->node, cow, true);
- BUG_ON(ret < 0);
+ if (ret < 0) {
+ btrfs_tree_unlock(cow);
+ free_extent_buffer(cow);
+ btrfs_abort_transaction(trans, ret);
+ return ret;
+ }
+ atomic_inc(&cow->refs);
rcu_assign_pointer(root->node, cow);

btrfs_free_tree_block(trans, btrfs_root_id(root), buf,