On Fri, Dec 6, 2019 at 2:38 PM Josef Bacik <josef@xxxxxxxxxxxxxx> wrote:
>
> My fsstress modifications coupled with generic/475 uncovered a failure
> to mount and replay the log if we hit a orphaned root. We do not want
> to replay the log for an orphan root, but it's completely legitimate to
> have an orphaned root with a log attached. Fix this by simply skipping
> replaying the log. We still need to pin it's root node so that we do
> not overwrite it while replaying other logs, as we re-read the log root
> at every stage of the replay.
>
> Signed-off-by: Josef Bacik <josef@xxxxxxxxxxxxxx>
Reviewed-by: Filipe Manana <fdmanana@xxxxxxxx>
Looks good, thanks.
> ---
> fs/btrfs/tree-log.c | 23 +++++++++++++++++++++--
> 1 file changed, 21 insertions(+), 2 deletions(-)
>
> diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
> index 6f757361db53..4bbb4fd490b5 100644
> --- a/fs/btrfs/tree-log.c
> +++ b/fs/btrfs/tree-log.c
> @@ -6294,9 +6294,28 @@ int btrfs_recover_log_trees(struct btrfs_root *log_root_tree)
> wc.replay_dest = btrfs_read_fs_root_no_name(fs_info, &tmp_key);
> if (IS_ERR(wc.replay_dest)) {
> ret = PTR_ERR(wc.replay_dest);
> +
> + /*
> + * We didn't find the subvol, likely because it was
> + * deleted. This is ok, simply skip this log and go to
> + * the next one.
> + *
> + * We need to exclude the root because we can't have
> + * other log replays overwriting this log as we'll read
> + * it back in a few more times. This will keep our
> + * block from being modified, and we'll just bail for
> + * each subsequent pass.
> + */
> + if (ret == -ENOENT)
> + ret = btrfs_pin_extent_for_log_replay(fs_info,
> + log->node->start,
> + log->node->len);
> free_extent_buffer(log->node);
> free_extent_buffer(log->commit_root);
> kfree(log);
> +
> + if (!ret)
> + goto next;
> btrfs_handle_fs_error(fs_info, ret,
> "Couldn't read target root for tree log recovery.");
> goto error;
> @@ -6328,7 +6347,6 @@ int btrfs_recover_log_trees(struct btrfs_root *log_root_tree)
> &root->highest_objectid);
> }
>
> - key.offset = found_key.offset - 1;
> wc.replay_dest->log_root = NULL;
> free_extent_buffer(log->node);
> free_extent_buffer(log->commit_root);
> @@ -6336,9 +6354,10 @@ int btrfs_recover_log_trees(struct btrfs_root *log_root_tree)
>
> if (ret)
> goto error;
> -
> +next:
> if (found_key.offset == 0)
> break;
> + key.offset = found_key.offset - 1;
> }
> btrfs_release_path(path);
>
> --
> 2.23.0
>
--
Filipe David Manana,
“Whether you think you can, or you think you can't — you're right.”
