Re: [PATCH v7 12/17] btrfs: reject raid5/6 fs for subpage

[Anand Jain <anand.jain@oracle.com>]

On 12/07/2021 16:30, Qu Wenruo wrote:
> Raid5/6 is not only unsafe due to its write-hole problem, but also has
> tons of hardcoded PAGE_SIZE.
> 
> So disable it for subpage support for now.
> 
> Signed-off-by: Qu Wenruo <wqu@suse.com>

Reviewed-by: Anand Jain <anand.jain@oracle.com>

Thanks.

> ---
>   fs/btrfs/disk-io.c | 10 ++++++++++
>   fs/btrfs/volumes.c |  7 +++++++
>   2 files changed, 17 insertions(+)
> 
> diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
> index b117dd3b8172..3de8e86f3170 100644
> --- a/fs/btrfs/disk-io.c
> +++ b/fs/btrfs/disk-io.c
> @@ -3402,6 +3402,16 @@ int __cold open_ctree(struct super_block *sb, struct btrfs_fs_devices *fs_device
>   			goto fail_alloc;
>   		}
>   	}
> +	if (sectorsize != PAGE_SIZE) {
> +		if (btrfs_super_incompat_flags(fs_info->super_copy) &
> +			BTRFS_FEATURE_INCOMPAT_RAID56) {
> +			btrfs_err(fs_info,
> +	"raid5/6 is not yet supported for sector size %u with page size %lu",
> +				sectorsize, PAGE_SIZE);
> +			err = -EINVAL;
> +			goto fail_alloc;
> +		}
> +	}
>   
>   	ret = btrfs_init_workqueues(fs_info, fs_devices);
>   	if (ret) {
> diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
> index f820c32f4a0d..279d5048b092 100644
> --- a/fs/btrfs/volumes.c
> +++ b/fs/btrfs/volumes.c
> @@ -3982,6 +3982,13 @@ static inline int validate_convert_profile(struct btrfs_fs_info *fs_info,
>   	if (!(bargs->flags & BTRFS_BALANCE_ARGS_CONVERT))
>   		return true;
>   
> +	if (fs_info->sectorsize < PAGE_SIZE &&
> +		bargs->target & BTRFS_BLOCK_GROUP_RAID56_MASK) {
> +		btrfs_err(fs_info,
> +	"RAID5/6 is not supported yet for sectorsize %u with page size %lu",
> +			  fs_info->sectorsize, PAGE_SIZE);
> +		return false;
> +	}
>   	/* Profile is valid and does not have bits outside of the allowed set */
>   	if (alloc_profile_is_valid(bargs->target, 1) &&
>   	    (bargs->target & ~allowed) == 0)
>