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

[Jaegeuk Kim <jaegeuk@kernel.org>]

Hi Fan,

Could you resubmit the final patch?
I'll remove the previous patch merged into dev branch.

Thanks,

On Thu, Feb 04, 2016 at 05:33:55PM +0800, Fan Li wrote:
> 
> 
> > -----Original Message-----
> > From: Junling Zheng [mailto:zhengjunling@huawei.com]
> > Sent: Thursday, February 04, 2016 10:52 AM
> > To: Fan Li; 'Jaegeuk Kim'; heyunlei@huawei.com
> > Cc: linux-f2fs-devel@lists.sourceforge.net
> > Subject: Re: [f2fs-dev] [PATCH v2] f2fs-tools: set segment_count in super block correctly
> > 
> > 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?
> 
> I'm afraid that my codes of mkfs is too old, it doesn't contain this patch, and it still
> uses section size to align main area.
> 
> Of course if main area should be aligned with zone, the following patch should be
> modified accordingly.
> 
> > 
> > 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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