[PATCH 6.4 763/800] btrfs: add missing error handling when logging operation while COWing extent buffer

Greg Kroah-Hartman
2023-07-16T20:29:54Z

From: Filipe Manana <fdmanana@suse.com>

commit d09c51521f22f9cbdfb1cf63e5c456077c622c84 upstream.

When COWing an extent buffer that is not the root node, we need to log in
the tree mod log that we replaced a pointer in the parent node, otherwise
a tree mod log user doing a search on the b+tree can return incorrect
results (that miss something). We are doing the call to
btrfs_tree_mod_log_insert_key() but we totally ignore its return value.

So fix this by adding the missing error handling, resulting in a
transaction abort and freeing the COWed extent buffer.

Fixes: f230475e62f7 ("Btrfs: put all block modifications into the tree mod log")
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 | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)

--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -594,8 +594,14 @@ static noinline int __btrfs_cow_block(st
add_root_to_dirty_list(root);
} else {
WARN_ON(trans->transid != btrfs_header_generation(parent));
- btrfs_tree_mod_log_insert_key(parent, parent_slot,
- BTRFS_MOD_LOG_KEY_REPLACE);
+ ret = btrfs_tree_mod_log_insert_key(parent, parent_slot,
+ BTRFS_MOD_LOG_KEY_REPLACE);
+ if (ret) {
+ btrfs_tree_unlock(cow);
+ free_extent_buffer(cow);
+ btrfs_abort_transaction(trans, ret);
+ return ret;
+ }
btrfs_set_node_blockptr(parent, parent_slot,
cow->start);
btrfs_set_node_ptr_generation(parent, parent_slot,