Re: [PATCH 1/2] btrfs-progs: mkfs: Fix minimal device size calculation for new temporary chunk layout

[Nikolay Borisov <nborisov@suse.com>]

On 24.01.2018 04:38, Qu Wenruo wrote:
> Commit 0b2161becf8e ("btrfs-progs: mkfs: Prevent temporary system chunk
> to use space in reserved 1M range") changed the hard-coded temporary
> chunk layout to avoid the first 1M.
> 
> However this also affects btrfs_min_dev_size() which still assume
> temporary chunks starts at device offset 0.
> 
> This patch will fix it.
> 
> Fixes: 0b2161becf8e ("btrfs-progs: mkfs: Prevent temporary system chunk
> to use space in reserved 1M range")
> Signed-off-by: Qu Wenruo <wqu@suse.com>

Reviewed-by: Nikolay Borisov <nborisov@suse.com>

> ---
>  mkfs/common.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/mkfs/common.c b/mkfs/common.c
> index 5c5e9c3b9e01..8e85942ef4eb 100644
> --- a/mkfs/common.c
> +++ b/mkfs/common.c
> @@ -483,6 +483,8 @@ u64 btrfs_min_dev_size(u32 nodesize, int mixed, u64 meta_profile,
>  
>  	/*
>  	 * Minimal size calculation is complex due to several factors:
> +	 * 0) Reserved 1M range.
> +	 *
>  	 * 1) Temporary chunk reuse
>  	 *    If specified chunk profile is SINGLE, we can reuse
>  	 *    temporary chunks, no need to allocate new chunks.
> @@ -501,7 +503,8 @@ u64 btrfs_min_dev_size(u32 nodesize, int mixed, u64 meta_profile,
>  	 * The latter two are all 8M, accroding to @calc_size of
>  	 * btrfs_alloc_chunk().
>  	 */
> -	reserved += BTRFS_MKFS_SYSTEM_GROUP_SIZE + SZ_8M * 2;
> +	reserved += BTRFS_BLOCK_RESERVED_1M_FOR_SUPER +
> +		    BTRFS_MKFS_SYSTEM_GROUP_SIZE + SZ_8M * 2;
>  
>  	/*
>  	 * For real chunks, we need to select different sizes:
>