Re: [PATCH 6.12.y] xfs: always warn about deprecated mount options

["Darrick J. Wong" <djwong@kernel.org>]

On Sun, Oct 26, 2025 at 02:04:22PM -0400, Sasha Levin wrote:
> From: "Darrick J. Wong" <djwong@kernel.org>
> 
> [ Upstream commit 630785bfbe12c3ee3ebccd8b530a98d632b7e39d ]
> 
> The deprecation of the 'attr2' mount option in 6.18 wasn't entirely
> successful because nobody noticed that the kernel never printed a
> warning about attr2 being set in fstab if the only xfs filesystem is the
> root fs; the initramfs mounts the root fs with no mount options; and the
> init scripts only conveyed the fstab options by remounting the root fs.
> 
> Fix this by making it complain all the time.
> 
> Cc: stable@vger.kernel.org # v5.13
> Fixes: 92cf7d36384b99 ("xfs: Skip repetitive warnings about mount options")
> Signed-off-by: Darrick J. Wong <djwong@kernel.org>
> Reviewed-by: Christoph Hellwig <hch@lst.de>
> Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
> Signed-off-by: Carlos Maiolino <cem@kernel.org>
> [ Update existing xfs_fs_warn_deprecated() callers ]
> Signed-off-by: Sasha Levin <sashal@kernel.org>

Looks good to me, thanks for fixing this up!
Acked-by: "Darrick J. Wong" <djwong@kernel.org>

--D

> ---
>  fs/xfs/xfs_super.c | 33 +++++++++++++++++++++------------
>  1 file changed, 21 insertions(+), 12 deletions(-)
> 
> diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
> index 201a86b3574da..77eaff6e16b15 100644
> --- a/fs/xfs/xfs_super.c
> +++ b/fs/xfs/xfs_super.c
> @@ -1232,16 +1232,25 @@ suffix_kstrtoint(
>  static inline void
>  xfs_fs_warn_deprecated(
>  	struct fs_context	*fc,
> -	struct fs_parameter	*param,
> -	uint64_t		flag,
> -	bool			value)
> +	struct fs_parameter	*param)
>  {
> -	/* Don't print the warning if reconfiguring and current mount point
> -	 * already had the flag set
> +	/*
> +	 * Always warn about someone passing in a deprecated mount option.
> +	 * Previously we wouldn't print the warning if we were reconfiguring
> +	 * and current mount point already had the flag set, but that was not
> +	 * the right thing to do.
> +	 *
> +	 * Many distributions mount the root filesystem with no options in the
> +	 * initramfs and rely on mount -a to remount the root fs with the
> +	 * options in fstab.  However, the old behavior meant that there would
> +	 * never be a warning about deprecated mount options for the root fs in
> +	 * /etc/fstab.  On a single-fs system, that means no warning at all.
> +	 *
> +	 * Compounding this problem are distribution scripts that copy
> +	 * /proc/mounts to fstab, which means that we can't remove mount
> +	 * options unless we're 100% sure they have only ever been advertised
> +	 * in /proc/mounts in response to explicitly provided mount options.
>  	 */
> -	if ((fc->purpose & FS_CONTEXT_FOR_RECONFIGURE) &&
> -            !!(XFS_M(fc->root->d_sb)->m_features & flag) == value)
> -		return;
>  	xfs_warn(fc->s_fs_info, "%s mount option is deprecated.", param->key);
>  }
>  
> @@ -1380,19 +1389,19 @@ xfs_fs_parse_param(
>  #endif
>  	/* Following mount options will be removed in September 2025 */
>  	case Opt_ikeep:
> -		xfs_fs_warn_deprecated(fc, param, XFS_FEAT_IKEEP, true);
> +		xfs_fs_warn_deprecated(fc, param);
>  		parsing_mp->m_features |= XFS_FEAT_IKEEP;
>  		return 0;
>  	case Opt_noikeep:
> -		xfs_fs_warn_deprecated(fc, param, XFS_FEAT_IKEEP, false);
> +		xfs_fs_warn_deprecated(fc, param);
>  		parsing_mp->m_features &= ~XFS_FEAT_IKEEP;
>  		return 0;
>  	case Opt_attr2:
> -		xfs_fs_warn_deprecated(fc, param, XFS_FEAT_ATTR2, true);
> +		xfs_fs_warn_deprecated(fc, param);
>  		parsing_mp->m_features |= XFS_FEAT_ATTR2;
>  		return 0;
>  	case Opt_noattr2:
> -		xfs_fs_warn_deprecated(fc, param, XFS_FEAT_NOATTR2, true);
> +		xfs_fs_warn_deprecated(fc, param);
>  		parsing_mp->m_features |= XFS_FEAT_NOATTR2;
>  		return 0;
>  	default:
> -- 
> 2.51.0
>