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From:   Daeho Jeong <daeho43@gmail.com>
Date:   Thu, 11 Jun 2020 11:05:12 +0900
Message-ID: <CACOAw_x3yC8ELYj7qSC7PM2RwpYRwQu7mT1vJhoFUQX4uzx2=w@mail.gmail.com>
Subject: Re: [f2fs-dev] [PATCH] f2fs: add F2FS_IOC_SEC_TRIM_FILE ioctl
To:     Eric Biggers <ebiggers@kernel.org>
Cc:     linux-kernel@vger.kernel.org,
        linux-f2fs-devel@lists.sourceforge.net, kernel-team@android.com,
        Daeho Jeong <daehojeong@google.com>
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Ok, I got it. Thanks for quick response~ :)

2020=EB=85=84 6=EC=9B=94 11=EC=9D=BC (=EB=AA=A9) =EC=98=A4=EC=A0=84 10:56, =
Eric Biggers <ebiggers@kernel.org>=EB=8B=98=EC=9D=B4 =EC=9E=91=EC=84=B1:
>
> On Thu, Jun 11, 2020 at 09:23:23AM +0900, Daeho Jeong wrote:
> > Yes, I saw the implementation in vfs_write().
> > But if we use mnt_want_write_file() here, it'll call mnt_clone_write()
> > internally if the file is already open in write mode.
> > Don't you think the below thing is needed? We can increase the counter
> > each of them, open and ioctl, like other filesystems such as ext4.
> >
> > int mnt_clone_write(struct vfsmount *mnt)
> > {
> >         /* superblock may be r/o */
> >         if (__mnt_is_readonly(mnt))
> >                 return -EROFS;
> >         preempt_disable();
> >         mnt_inc_writers(real_mount(mnt));
> >         preempt_enable();
> >         return 0;
> > }
>
> No, this seems to be left over from when mnt_want_write_file() was paired=
 with
> mnt_drop_write() instead of mnt_drop_write_file().  I sent a patch to rem=
ove it:
> https://lkml.kernel.org/r/20200611014945.237210-1-ebiggers@kernel.org
>
> - Eric