linux-kernel - Re: [PATCH v2] fs/xfs: replace strncpy with memtostr

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Message-ID: <5cwrwinj6j6nqhk2gc6aj4th3csls5ga3noydzykj6fkk2v4zi@qvboar3cyh7x>
Date: Tue, 15 Jul 2025 10:41:28 +0200
From: Carlos Maiolino <cem@...nel.org>
To: Pranav Tyagi <pranav.tyagi03@...il.com>
Cc: linux-xfs@...r.kernel.org, linux-kernel@...r.kernel.org, 
	djwong@...nel.org, skhan@...uxfoundation.org, linux-kernel-mentees@...ts.linux.dev
Subject: Re: [PATCH v2] fs/xfs: replace strncpy with memtostr_pad()

On Thu, Jul 10, 2025 at 03:56:01PM +0530, Pranav Tyagi wrote:
> On Fri, Jul 4, 2025 at 3:42 PM Pranav Tyagi <pranav.tyagi03@...il.com> wrote:
> >
> > Replace the deprecated strncpy() with memtostr_pad(). This also avoids
> > the need for separate zeroing using memset(). Mark sb_fname buffer with
> > __nonstring as its size is XFSLABEL_MAX and so no terminating NULL for
> > sb_fname.
> >
> > Signed-off-by: Pranav Tyagi <pranav.tyagi03@...il.com>
> > ---
> >  fs/xfs/libxfs/xfs_format.h | 2 +-
> >  fs/xfs/xfs_ioctl.c         | 3 +--
> >  2 files changed, 2 insertions(+), 3 deletions(-)
> >
> > diff --git a/fs/xfs/libxfs/xfs_format.h b/fs/xfs/libxfs/xfs_format.h
> > index 9566a7623365..779dac59b1f3 100644
> > --- a/fs/xfs/libxfs/xfs_format.h
> > +++ b/fs/xfs/libxfs/xfs_format.h
> > @@ -112,7 +112,7 @@ typedef struct xfs_sb {
> >         uint16_t        sb_sectsize;    /* volume sector size, bytes */
> >         uint16_t        sb_inodesize;   /* inode size, bytes */
> >         uint16_t        sb_inopblock;   /* inodes per block */
> > -       char            sb_fname[XFSLABEL_MAX]; /* file system name */
> > +       char            sb_fname[XFSLABEL_MAX] __nonstring; /* file system name */
> >         uint8_t         sb_blocklog;    /* log2 of sb_blocksize */
> >         uint8_t         sb_sectlog;     /* log2 of sb_sectsize */
> >         uint8_t         sb_inodelog;    /* log2 of sb_inodesize */
> > diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
> > index d250f7f74e3b..c3e8c5c1084f 100644
> > --- a/fs/xfs/xfs_ioctl.c
> > +++ b/fs/xfs/xfs_ioctl.c
> > @@ -990,9 +990,8 @@ xfs_ioc_getlabel(
> >         BUILD_BUG_ON(sizeof(sbp->sb_fname) > FSLABEL_MAX);
> >
> >         /* 1 larger than sb_fname, so this ensures a trailing NUL char */
> > -       memset(label, 0, sizeof(label));
> >         spin_lock(&mp->m_sb_lock);
> > -       strncpy(label, sbp->sb_fname, XFSLABEL_MAX);
> > +       memtostr_pad(label, sbp->sb_fname);
> >         spin_unlock(&mp->m_sb_lock);
> >
> >         if (copy_to_user(user_label, label, sizeof(label)))
> > --
> > 2.49.0
> >
> Hi,
> 
> This is a gentle follow-up on this patch. I would like to
> know if there is any update on its state.

Looks fine to me:

Reviewed-by: Carlos Maiolino <cmaiolino@...hat.com>


> 
> Regards
> Pranav Tyagi
>