[Cluster-devel] [PATCH v2 1/2] fs: warn about impending deprecation of mandatory locks

[Jeff Layton]

We've had CONFIG_MANDATORY_FILE_LOCKING since 2015 and a lot of distros
have disabled it. Warn the stragglers that still use "-o mand" that
we'll be dropping support for that mount option.

Cc: stable at vger.kernel.org
Signed-off-by: Jeff Layton <jlayton at kernel.org>
---
 fs/namespace.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/fs/namespace.c b/fs/namespace.c
index ab4174a3c802..ffab0bb1e649 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -1716,8 +1716,16 @@ static inline bool may_mount(void)
 }
 
 #ifdef	CONFIG_MANDATORY_FILE_LOCKING
+static bool warned_mand;
 static inline bool may_mandlock(void)
 {
+	if (!warned_mand) {
+		warned_mand = true;
+		pr_warn("======================================================\n");
+		pr_warn("WARNING: the mand mount option is being deprecated and\n");
+		pr_warn("         will be removed in v5.15!\n");
+		pr_warn("======================================================\n");
+	}
 	return capable(CAP_SYS_ADMIN);
 }
 #else
-- 
2.31.1