Re: [PATCH v2] f2fs-tools: set segment_count in super block correctly

[Junling Zheng <zhengjunling@huawei.com>]

On 2016/2/3 13:29, Fan Li wrote:
> Now f2fs will check statistics recorded in super block in 
> sanity_check_area_boundary() during mount,if number of segments per 
> section is greater than 1, and the disk space isn't aligned with section,

Hi Fan, Hi Kim:

I'm uncertain about which unit the disk space should be aligned with? section or zone?

It looks like commit "e9dfbbb"(mkfs.f2fs: introduce zone align for main area)

from Yunlei had changed the aligning unit from section to zone.

So, should segment_count in superblock be aligned with zone rather than section?

Thanks,

Junling

> mount will fail due to following condition:
> 
> main_blkaddr + (segment_count_main << log_blocks_per_seg) !=
> 		segment0_blkaddr + (segment_count << log_blocks_per_seg)
> 
> this is because when the length of main area isn't aligned with section, 
> mkfs didn't add the number of excess segments to segment_count_main, but 
> add it to segment_count. 
> Here align segment_count with section size first to prevent such problem.
> 
> Signed-off-by: Fan Li <fanofcode.li@samsung.com>
> ---
>  mkfs/f2fs_format.c |    3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/mkfs/f2fs_format.c b/mkfs/f2fs_format.c
> index 66d7342..3366302 100644
> --- a/mkfs/f2fs_format.c
> +++ b/mkfs/f2fs_format.c
> @@ -174,7 +174,8 @@ static int f2fs_prepare_super_block(void)
>         }
> 
>         set_sb(segment_count, (config.total_sectors * config.sector_size -
> -                               zone_align_start_offset) / segment_size_bytes);
> +                               zone_align_start_offset) / segment_size_bytes /
> +                               config.segs_per_sec * config.segs_per_sec);
> 
>         set_sb(segment0_blkaddr, zone_align_start_offset / blk_size_bytes);
>         sb->cp_blkaddr = sb->segment0_blkaddr;
> 



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