Re: [PATCH] Btrfs: don't ignore log btree writeback errors

["Holger Hoffstätte" <holger.hoffstaette@googlemail.com>]

On Thu, 13 Nov 2014 16:59:53 +0000, Filipe Manana wrote:

> If an error happens during writeback of log btree extents, make sure the
> error is returned to the caller (fsync), so that it takes proper action
> (commit current transaction) instead of writing a superblock that points
> to log btrees with all or some nodes that weren't durably persisted.
> 
> Signed-off-by: Filipe Manana <fdmanana@suse.com>
> ---
>  fs/btrfs/tree-log.c | 21 +++++++++++++++------
>  1 file changed, 15 insertions(+), 6 deletions(-)
> 
> diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
> index 6d58d72..c8274d3 100644
> --- a/fs/btrfs/tree-log.c
> +++ b/fs/btrfs/tree-log.c
> @@ -2599,12 +2599,14 @@ int btrfs_sync_log(struct btrfs_trans_handle *trans,
>  	index2 = root_log_ctx.log_transid % 2;
>  	if (atomic_read(&log_root_tree->log_commit[index2])) {
>  		blk_finish_plug(&plug);
> -		btrfs_wait_marked_extents(log, &log->dirty_log_pages, mark);
> +		ret = btrfs_wait_marked_extents(log, &log->dirty_log_pages,
> +						mark);
>  		wait_log_commit(trans, log_root_tree,
>  				root_log_ctx.log_transid);
>  		btrfs_free_logged_extents(log, log_transid);
>  		mutex_unlock(&log_root_tree->log_mutex);
> -		ret = root_log_ctx.log_ret;
> +		if (!ret)
> +			ret = root_log_ctx.log_ret;
>  		goto out;
>  	}
>  	ASSERT(root_log_ctx.log_transid == log_root_tree->log_transid);

This first hunk didn't apply to my 3.14.x tree that is 99.999% in sync with
btrfs-3.18+, as a line is missing from the context. See:

https://git.kernel.org/cgit/linux/kernel/git/mason/linux-btrfs.git/tree/fs/btrfs/tree-log.c?h=for-linus#n2605

Any idea where that missing btrfs_free_logged_extents() went?

cheers
Holger