Re: [PATCH v4 2/7] btrfs: rst: don't print tree dump in case lookup fails

[Qu Wenruo <quwenruo.btrfs@gmx.com>]

在 2024/7/6 00:43, Johannes Thumshirn 写道:
> From: Johannes Thumshirn <johannes.thumshirn@wdc.com>
>
> Don't print tree dump in case a raid-stripe-tree lookup fails.
>
> Dumping the stripe tree in case of a lookup failure was originally
> intended to be a debug feature, but it turned out to be a problem, in case
> of i.e. readahead.

But why readahead is going to cause problem?

IIRC the readahead is still based on file, in that case it still needs
to go through the data extents, then rst mapping.

Thus mind you explain more on the readahead problem?

Thanks,
Qu
>
> Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
> ---
>   fs/btrfs/raid-stripe-tree.c | 6 ++----
>   1 file changed, 2 insertions(+), 4 deletions(-)
>
> diff --git a/fs/btrfs/raid-stripe-tree.c b/fs/btrfs/raid-stripe-tree.c
> index 3b32e96c33fc..84746c8886be 100644
> --- a/fs/btrfs/raid-stripe-tree.c
> +++ b/fs/btrfs/raid-stripe-tree.c
> @@ -281,10 +281,8 @@ int btrfs_get_raid_extent_offset(struct btrfs_fs_info *fs_info,
>   out:
>   	if (ret > 0)
>   		ret = -ENOENT;
> -	if (ret && ret != -EIO && !stripe->is_scrub) {
> -		if (IS_ENABLED(CONFIG_BTRFS_DEBUG))
> -			btrfs_print_tree(leaf, 1);
> -		btrfs_err(fs_info,
> +	if (ret && ret != -EIO) {
> +		btrfs_debug(fs_info,
>   		"cannot find raid-stripe for logical [%llu, %llu] devid %llu, profile %s",
>   			  logical, logical + *length, stripe->dev->devid,
>   			  btrfs_bg_type_to_raid_name(map_type));
>