[PATCH 6.17.y] xfs: always warn about deprecated mount options

[Sasha Levin <sashal@kernel.org>]

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>
---
 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 bb0a82635a770..9a7dd3a36f74f 100644
--- a/fs/xfs/xfs_super.c
+++ b/fs/xfs/xfs_super.c
@@ -1386,16 +1386,25 @@ suffix_kstrtoull(
 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);
 }
 
@@ -1543,19 +1552,19 @@ 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;
 	case Opt_max_open_zones:
-- 
2.51.0