Re: [PATCH v5 06/13] btrfs: lookup physical address from stripe extent

[Josef Bacik <josef@toxicpanda.com>]

On Wed, Feb 08, 2023 at 02:57:43AM -0800, Johannes Thumshirn wrote:
> Lookup the physical address from the raid stripe tree when a read on an
> RAID volume formatted with the raid stripe tree was attempted.
> 
> If the requested logical address was not found in the stripe tree, it may
> still be in the in-memory ordered stripe tree, so fallback to searching
> the ordered stripe tree in this case.
> 
> Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
> ---
>  fs/btrfs/raid-stripe-tree.c | 145 ++++++++++++++++++++++++++++++++++++
>  fs/btrfs/raid-stripe-tree.h |   3 +
>  fs/btrfs/volumes.c          |  31 ++++++--
>  3 files changed, 172 insertions(+), 7 deletions(-)
> 
> diff --git a/fs/btrfs/raid-stripe-tree.c b/fs/btrfs/raid-stripe-tree.c
> index ff5787a19454..ba7015a8012c 100644
> --- a/fs/btrfs/raid-stripe-tree.c
> +++ b/fs/btrfs/raid-stripe-tree.c
> @@ -231,3 +231,148 @@ int btrfs_insert_raid_extent(struct btrfs_trans_handle *trans,
>  
>  	return ret;
>  }
> +
> +static bool btrfs_physical_from_ordered_stripe(struct btrfs_fs_info *fs_info,
> +					      u64 logical, u64 *length,
> +					      int num_stripes,
> +					      struct btrfs_io_stripe *stripe)
> +{
> +	struct btrfs_ordered_stripe *os;
> +	u64 offset;
> +	u64 found_end;
> +	u64 end;
> +	int i;
> +
> +	os = btrfs_lookup_ordered_stripe(fs_info, logical);
> +	if (!os)
> +		return false;
> +
> +	end = logical + *length;
> +	found_end = os->logical + os->num_bytes;
> +	if (end > found_end)
> +		*length -= end - found_end;
> +
> +	for (i = 0; i < num_stripes; i++) {
> +		if (os->stripes[i].dev != stripe->dev)
> +			continue;
> +
> +		offset = logical - os->logical;
> +		ASSERT(offset >= 0);

This is always going to be true, should probably be

ASSERT(logical >= os->logical);

otherwise you can add

Reviewed-by: Josef Bacik <josef@toxicpanda.com>

Thanks,

Josef