linux-kernel - Re: [f2fs-dev] [PATCH v2] f2fs: introduce F2FS_IOC_START_ATOMIC

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Date:   Fri, 30 Sep 2022 09:04:19 -0700
From:   Daeho Jeong <daeho43@...il.com>
To:     Chao Yu <chao@...nel.org>
Cc:     linux-kernel@...r.kernel.org,
        linux-f2fs-devel@...ts.sourceforge.net, kernel-team@...roid.com,
        Daeho Jeong <daehojeong@...gle.com>
Subject: Re: [f2fs-dev] [PATCH v2] f2fs: introduce F2FS_IOC_START_ATOMIC_REPLACE

> >>>>
> >>>> Hi Daeho,
> >>>>
> >>>> isize should be updated after tagging inode as atomic_write one?
> >>>> otherwise f2fs_mark_inode_dirty_sync() may update isize to inode page,
> >>>> latter checkpoint may persist that change? IIUC...
> >>>>
> >>>> Thanks,
> >>>
> >>> Hi Chao,
> >>>
> >>> The first patch of this patchset prevents the inode page from being
> >>> updated as dirty for atomic file cases.
> >>> Is there any other chances for the inode page to be marked as dirty?
> >>
> >> I mean:
> >>
> >> Thread A                                Thread B
> >> - f2fs_ioc_start_atomic_write
> >>    - f2fs_i_size_write(inode, 0)
> >>     - f2fs_mark_inode_dirty_sync
> >>                                          - checkpoint
> >>                                           - persist inode with incorrect zero isize
> >>
> >>    - set_inode_flag(inode, FI_ATOMIC_FILE)
> >>
> >> Am I missing something?
> >>
> >
> > So, f2fs_mark_inode_dirty_sync() will not work for atomic files
> > anymore, which means it doesn't make the inode dirty.
> > Plz, refer to the first patch of this patchset. Or I might be confused
> > with something. :(
>
> I mean FI_ATOMIC_FILE was set after f2fs_i_size_write(), so inode will be set
> as dirty.
>
> Thanks,
>

Oh, I was confused that f2fs_update_inode() is called in
f2fs_mark_inode_dirty_sync().
That is called in f2fs_write_inode(). Let me fix this.

Thanks,