Re: [PATCH] btrfs-progs: mkfs: refactor how we handle sectorsize override

[David Sterba <dsterba@suse.cz>]

On Tue, Oct 13, 2020 at 09:06:02AM +0800, Qu Wenruo wrote:
> There are several problems for current sectorsize check:
> - No check at all for sectorsize
>   This means you can even specify "-s 62k".
> 
> - No way to specify sectorsize smaller than page size
> 
> Fix all these problems by:
> - Introduce btrfs_check_sectorsize()
>   To do:
>   * power of 2 check for sectorsize
>   * lower and upper boundary check for sectorsize
>   * warn about sectorsize mismatch with page size
> 
> - Remove the max() between page size and sectorsize
>   This allows us to override the sectorsize for 64K page systems.
> 
> - Make nodesize calculation based on sectorsize
>   No need to use page size any more.
>   Users who specify sectorsize manually really know what they are doing,
>   and we have warned them already.
> 
> Signed-off-by: Qu Wenruo <wqu@suse.com>

Added to devel, thanks.

> +int btrfs_check_sectorsize(u32 sectorsize)
> +{
> +	u32 page_size = (u32)sysconf(_SC_PAGESIZE);
> +
> +	if (!is_power_of_2(sectorsize)) {
> +		error("illegal sectorsize %u, expect value power of 2",
> +		      sectorsize);
> +		return -EUCLEAN;

This should be EINVAL, updated

> +	}
> +	if (sectorsize < SZ_4K || sectorsize > SZ_64K) {
> +		error("illegal sectorsize %u, expect range [4K, 64K]",
> +		      sectorsize);
> +		return -EUCLEAN;
> +	}
> +	if (page_size != sectorsize)
> +		warning(
> +"the fs may not be mountable, sectorsize %u doesn't match page size %u",
> +			sectorsize, page_size);
> +	return 0;
> +}