Hi Chao,
On Thu, Feb 05, 2015 at 04:16:04PM +0800, Chao Yu wrote:
> Hi Jaegeuk,
>
> > -----Original Message-----
> > From: Jaegeuk Kim [mailto:jaeg...@kernel.org]
> > Sent: Tuesday, February 03, 2015 7:38 AM
> > To: Chao Yu
> > Cc: Changman Lee; linux-f2fs-de...@lists.sourceforge.net;
> > linux-kernel@vger.kernel.org
> > Subject: Re: [PATCH 2/2] f2fs: don't discard next free dnode page for an
> > umount checkpoint
> >
> > Hi Chao,
> >
> > On Sat, Jan 31, 2015 at 05:06:59PM +0800, Chao Yu wrote:
> > > Previously, discard_next_dnode is added before a checkpoint to prevent
> > > that we
> > > may meet a garbage dnode page readed from next free blkaddr in recover
> > > flow.
> > >
> > > Since f2fs will skip recovery flow for a clean umount image, this
> > > condition will
> > > never happen.
> > >
> > > So it's safe for us to leave next free dnode as it is in an umount
> > > checkpoint.
> > >
> > > Signed-off-by: Chao Yu <chao2...@samsung.com>
> > > ---
> > > fs/f2fs/checkpoint.c | 6 +++++-
> > > 1 file changed, 5 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
> > > index f7cdcad..991fd0a 100644
> > > --- a/fs/f2fs/checkpoint.c
> > > +++ b/fs/f2fs/checkpoint.c
> > > @@ -905,8 +905,12 @@ static void do_checkpoint(struct f2fs_sb_info *sbi,
> > > struct cp_control
> > *cpc)
> > > /*
> > > * This avoids to conduct wrong roll-forward operations and uses
> > > * metapages, so should be called prior to sync_meta_pages below.
> > > + * But if we are in an umount checkpoint, we'd better skip this
> > > + * because we will not enter recovery flow to use the next free
> > > + * blkaddr when mounting it.
> > > */
> > > - discard_next_dnode(sbi, NEXT_FREE_BLKADDR(sbi, curseg));
> > > + if (cpc->reason != CP_UMOUNT)
> > > + discard_next_dnode(sbi, NEXT_FREE_BLKADDR(sbi, curseg));
> >
> > The reason for discard_next_dnode is to avoid wrong execution due to old
> > mkfs.f2fs which remains gabage data.
> > It needs to do all the time.
>
> Maybe my previously understanding is wrong.
>
> Is this issue due to old mkfs.f2fs do not discard entire flash storage device
> when formating? Or another bug of mkfs? If so, can you please offer a fix
> commit id of mkfs?
commit ffbada4298c7aed059bb99a8d553d6dd555963c0
Author: Jaegeuk Kim <jaegeuk....@samsung.com>
Date: Mon Nov 11 13:29:11 2013 +0900
mkfs: remove stale node blocks
If the device does not support discard, we should write zero blocks
to avoid roll-forward recovery.
Thanks,
>
> I'm curious about how this happened. :-)
>
> Thanks,
> >
> > Thanks,
> >
> > >
> > > /* Flush all the NAT/SIT pages */
> > > while (get_pages(sbi, F2FS_DIRTY_META)) {
> > > --
> > > 2.2.1
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