btrfs: always report error in run_one_delayed_ref()
authorQu Wenruo <wqu@suse.com>
Mon, 26 Dec 2022 01:00:40 +0000 (09:00 +0800)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Tue, 24 Jan 2023 06:22:42 +0000 (07:22 +0100)
commitfdb4a70bb768d2a87890409597529ad81cb3de8a
tree4e6510ac732ad84edc6ff84a03fe9f0f4d7579ad
parentf641067ea2af0523de39b8ced75cb59a2e7cc6fe
btrfs: always report error in run_one_delayed_ref()

[ Upstream commit 39f501d68ec1ed5cd5c66ac6ec2a7131c517bb92 ]

Currently we have a btrfs_debug() for run_one_delayed_ref() failure, but
if end users hit such problem, there will be no chance that
btrfs_debug() is enabled.  This can lead to very little useful info for
debugging.

This patch will:

- Add extra info for error reporting
  Including:
  * logical bytenr
  * num_bytes
  * type
  * action
  * ref_mod

- Replace the btrfs_debug() with btrfs_err()

- Move the error reporting into run_one_delayed_ref()
  This is to avoid use-after-free, the @node can be freed in the caller.

This error should only be triggered at most once.

As if run_one_delayed_ref() failed, we trigger the error message, then
causing the call chain to error out:

btrfs_run_delayed_refs()
`- btrfs_run_delayed_refs()
   `- btrfs_run_delayed_refs_for_head()
      `- run_one_delayed_ref()

And we will abort the current transaction in btrfs_run_delayed_refs().
If we have to run delayed refs for the abort transaction,
run_one_delayed_ref() will just cleanup the refs and do nothing, thus no
new error messages would be output.

Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
fs/btrfs/extent-tree.c