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

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Date: Fri, 26 Apr 2024 07:14:50 -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 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.

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)) {
                ret = -EIO;
                goto out_unlock;
        }


>