linux-kernel - Re: [PATCH] f2fs: zone: fix to don't trigger OPU on pinfile for direct IO

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Date: Sat, 27 Apr 2024 12:50:48 -0700
From: Daeho Jeong <daeho43@...il.com>
To: Chao Yu <chao@...nel.org>
Cc: jaegeuk@...nel.org, linux-f2fs-devel@...ts.sourceforge.net, 
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] f2fs: zone: fix to don't trigger OPU on pinfile for
 direct IO

On Fri, Apr 26, 2024 at 6:49 PM Chao Yu <chao@...nel.org> wrote:
>
> On 2024/4/26 22:14, Daeho Jeong wrote:
> > On Fri, Apr 26, 2024 at 3:35 AM Chao Yu <chao@...nel.org> wrote:
> >>
> >> Otherwise, it breaks pinfile's sematics.
> >>
> >> Cc: Daeho Jeong <daeho43@...il.com>
> >> Signed-off-by: Chao Yu <chao@...nel.org>
> >> ---
> >>   fs/f2fs/data.c | 3 ++-
> >>   1 file changed, 2 insertions(+), 1 deletion(-)
> >>
> >> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> >> index bee1e45f76b8..e29000d83d52 100644
> >> --- a/fs/f2fs/data.c
> >> +++ b/fs/f2fs/data.c
> >> @@ -1596,7 +1596,8 @@ int f2fs_map_blocks(struct inode *inode, struct f2fs_map_blocks *map, int flag)
> >>
> >>          /* use out-place-update for direct IO under LFS mode */
> >>          if (map->m_may_create &&
> >> -           (is_hole || (f2fs_lfs_mode(sbi) && flag == F2FS_GET_BLOCK_DIO))) {
> >> +           (is_hole || (flag == F2FS_GET_BLOCK_DIO && (f2fs_lfs_mode(sbi) &&
> >> +           (!f2fs_sb_has_blkzoned(sbi) || !f2fs_is_pinned_file(inode)))))) {
> >>                  if (unlikely(f2fs_cp_error(sbi))) {
> >>                          err = -EIO;
> >>                          goto sync_out;
> >> --
> >> 2.40.1
> >
> > So, we block overwrite io for the pinfile here.
>
> I guess you mean we blocked append write for pinfile, right?
>
> >
> > static ssize_t f2fs_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
> >
> > {
> > ...
> >          if (f2fs_is_pinned_file(inode) &&
> >              !f2fs_overwrite_io(inode, pos, count)) {
>
> If !f2fs_overwrite_io() is true, it means it may trigger append write on
> pinfile?

Yes, I missed it. Thanks~

>
> Thanks,
>
> >                  ret = -EIO;
> >                  goto out_unlock;
> >          }
> >
> >
> >>