linux-kernel - Re: [f2fs-dev] [RFC PATCH] f2fs: remove some redundant flow about FI_ATOMIC

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Message-ID: <CACOAw_wX3QPvpaCWW2gfKH_9Zf_=Tku14+RL6CatU9f2d2AiGQ@mail.gmail.com>
Date: Wed, 26 Mar 2025 11:51:05 -0700
From: Daeho Jeong <daeho43@...il.com>
To: Chao Yu <chao@...nel.org>
Cc: Zhiguo Niu <niuzhiguo84@...il.com>, daehojeong@...gle.com, ke.wang@...soc.com, 
	linux-kernel@...r.kernel.org, linux-f2fs-devel@...ts.sourceforge.net, 
	Zhiguo Niu <zhiguo.niu@...soc.com>, jaegeuk@...nel.org, Hao_hao.Wang@...soc.com
Subject: Re: [f2fs-dev] [RFC PATCH] f2fs: remove some redundant flow about FI_ATOMIC_DIRTIED

On Wed, Mar 26, 2025 at 5:12 AM Chao Yu via Linux-f2fs-devel
<linux-f2fs-devel@...ts.sourceforge.net> wrote:
>
> On 3/26/25 18:51, Zhiguo Niu wrote:
> > Chao Yu <chao@...nel.org> 于2025年3月26日周三 17:26写道：
> >>
> >> On 3/26/25 16:46, Zhiguo Niu wrote:
> >>> Commit fccaa81de87e ("f2fs: prevent atomic file from being dirtied before commit")
> >>> adds the processing of FI_ATOMIC_DIRTIED in the following two positions,
> >>> [1]
> >>> f2fs_commit_atomic_write
> >>>  - __f2fs_commit_atomic_write
> >>>   - sbi->committed_atomic_block += fi->atomic_write_cnt;
> >>>   - set_inode_flag(inode, FI_ATOMIC_COMMITTED);
> >>>   - if (is_inode_flag_set(inode, FI_ATOMIC_DIRTIED)) {
> >>>   -    clear_inode_flag(inode, FI_ATOMIC_DIRTIED);
> >>>   -    f2fs_mark_inode_dirty_sync(inode, true);
> >>>   - }
> >>> [2]
> >>> f2fs_abort_atomic_write
> >>>   - if (is_inode_flag_set(inode, FI_ATOMIC_DIRTIED)) {
> >>>   -    clear_inode_flag(inode, FI_ATOMIC_DIRTIED);
> >>>   -    f2fs_mark_inode_dirty_sync(inode, true);
> >>>   - }
> >>>
> >>> but [1] seems to be redundant:
> >>> The atomic file flag FI_ATOMIC_FILE is still set here, so f2fs_mark_inode_dirty_sync
> >>> still does not set the dirty state to vfs. If FI_ATOMIC_DIRTIED was originally set
> >>> when atomic file is committing, then FI_ATOMIC_DIRTIED is just cleared here, and
> >>> then do the repeating action of setting FI_ATOMIC_DIRTIED?
> >>> So is it enough to do this only in [2]?
> >>
> >> Hi Zhiguo,
> >>
> >> I checked the code again, finally, I got this, could you please take
> >> a look?
> >>
> >> Ping Daeho as well.
> >>
> >> Subject: [PATCH] f2fs: fix to set atomic write status more clear
> >>
> >> 1. After we start atomic write in a database file, before committing
> >> all data, we'd better not set inode w/ vfs dirty status to avoid
> >> redundant updates, instead, we only set inode w/ atomic dirty status.
> >>
> >> 2. After we commit all data, before committing metadata, we need to
> >> clear atomic dirty status, and set vfs dirty status to allow vfs flush
> >> dirty inode.
> >>
> > Hi Chao,
> > these looks more clear.
> >> Signed-off-by: Chao Yu <chao@...nel.org>
> >> ---
> >>  fs/f2fs/inode.c   |  4 +++-
> >>  fs/f2fs/segment.c | 10 ++++++----
> >>  fs/f2fs/super.c   |  4 +++-
> >>  3 files changed, 12 insertions(+), 6 deletions(-)
> >>
> >> diff --git a/fs/f2fs/inode.c b/fs/f2fs/inode.c
> >> index 5c8634eaef7b..f5991e8751b9 100644
> >> --- a/fs/f2fs/inode.c
> >> +++ b/fs/f2fs/inode.c
> >> @@ -34,7 +34,9 @@ void f2fs_mark_inode_dirty_sync(struct inode *inode, bool sync)
> >>         if (f2fs_inode_dirtied(inode, sync))
> >>                 return;
> >>
> >> -       if (f2fs_is_atomic_file(inode))
> >> +       /* only atomic file w/ FI_ATOMIC_COMMITTED can be set vfs dirty */
> >> +       if (f2fs_is_atomic_file(inode) &&
> >> +                       !is_inode_flag_set(inode, FI_ATOMIC_COMMITTED))
> >>                 return;
> >>
> >>         mark_inode_dirty_sync(inode);
> >> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> >> index dc360b4b0569..28659a71891a 100644
> >> --- a/fs/f2fs/segment.c
> >> +++ b/fs/f2fs/segment.c
> >> @@ -376,10 +376,12 @@ static int __f2fs_commit_atomic_write(struct inode *inode)
> >>         } else {
> >>                 sbi->committed_atomic_block += fi->atomic_write_cnt;
> >>                 set_inode_flag(inode, FI_ATOMIC_COMMITTED);
> >> -               if (is_inode_flag_set(inode, FI_ATOMIC_DIRTIED)) {
> >> -                       clear_inode_flag(inode, FI_ATOMIC_DIRTIED);
> >> -                       f2fs_mark_inode_dirty_sync(inode, true);
> >> -               }
> >> +
> >> +               f2fs_bug_on(sbi, !is_inode_flag_set(inode, FI_ATOMIC_DIRTIED));
> > but FI_ATOMIC_DIRTIED may  not be set when atomic file is committing?
> > thanks!
>
> inc_valid_block_count() will set FI_ATOMIC_DIRTIED for inode at least?
>
> - __f2fs_commit_atomic_write
>  - __replace_atomic_write_block
>   - inc_valid_block_count
>    - f2fs_i_blocks_write
>     - f2fs_mark_inode_dirty_sync

Maybe, no write scenario? open -> atomic_write_start -> no write -> commit?

>
> Thanks,
>
> >> +
> >> +               /* clear atomic dirty status and set vfs dirty status */
> >> +               clear_inode_flag(inode, FI_ATOMIC_DIRTIED);
> >> +               f2fs_mark_inode_dirty_sync(inode, true);
> >>         }
> >>
> >>         __complete_revoke_list(inode, &revoke_list, ret ? true : false);
> >> diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
> >> index 9a42a1323f42..a5cc9f6ee16a 100644
> >> --- a/fs/f2fs/super.c
> >> +++ b/fs/f2fs/super.c
> >> @@ -1532,7 +1532,9 @@ int f2fs_inode_dirtied(struct inode *inode, bool sync)
> >>         }
> >>         spin_unlock(&sbi->inode_lock[DIRTY_META]);
> >>
> >> -       if (!ret && f2fs_is_atomic_file(inode))
> >> +       /* if atomic write is not committed, set inode w/ atomic dirty */
> >> +       if (!ret && f2fs_is_atomic_file(inode) &&
> >> +                       !is_inode_flag_set(inode, FI_ATOMIC_COMMITTED))
> >>                 set_inode_flag(inode, FI_ATOMIC_DIRTIED);
> >>
> >>         return ret;
> >> --
> >> 2.48.1
> >>
> >>
> >>>
> >>> Cc: Daeho Jeong <daehojeong@...gle.com>
> >>> Fixes: fccaa81de87e ("f2fs: prevent atomic file from being dirtied before commit")
> >>> Signed-off-by: Zhiguo Niu <zhiguo.niu@...soc.com>
> >>> ---
> >>>  fs/f2fs/segment.c | 4 ----
> >>>  1 file changed, 4 deletions(-)
> >>>
> >>> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> >>> index 396ef71..d4ea3af 100644
> >>> --- a/fs/f2fs/segment.c
> >>> +++ b/fs/f2fs/segment.c
> >>> @@ -376,10 +376,6 @@ static int __f2fs_commit_atomic_write(struct inode *inode)
> >>>       } else {
> >>>               sbi->committed_atomic_block += fi->atomic_write_cnt;
> >>>               set_inode_flag(inode, FI_ATOMIC_COMMITTED);
> >>> -             if (is_inode_flag_set(inode, FI_ATOMIC_DIRTIED)) {
> >>> -                     clear_inode_flag(inode, FI_ATOMIC_DIRTIED);
> >>> -                     f2fs_mark_inode_dirty_sync(inode, true);
> >>> -             }
> >>>       }
> >>>
> >>>       __complete_revoke_list(inode, &revoke_list, ret ? true : false);
> >>
>
>
>
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