From df2474a22c42ce419b67067c52d71da06c385501 Mon Sep 17 00:00:00 2001 From: Jeff Layton Date: Thu, 15 Aug 2019 15:21:17 -0400 Subject: locks: print a warning when mount fails due to lack of "mand" support Since 9e8925b67a ("locks: Allow disabling mandatory locking at compile time"), attempts to mount filesystems with "-o mand" will fail. Unfortunately, there is no other indiciation of the reason for the failure. Change how the function is defined for better readability. When CONFIG_MANDATORY_FILE_LOCKING is disabled, printk a warning when someone attempts to mount with -o mand. Also, add a blurb to the mandatory-locking.txt file to explain about the "mand" option, and the behavior one should expect when it is disabled. Reported-by: Jan Kara Reviewed-by: Jan Kara Signed-off-by: Jeff Layton --- fs/namespace.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) (limited to 'fs/namespace.c') diff --git a/fs/namespace.c b/fs/namespace.c index 6464ea4acba9..602bd78ba572 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -1643,13 +1643,18 @@ static inline bool may_mount(void) return ns_capable(current->nsproxy->mnt_ns->user_ns, CAP_SYS_ADMIN); } +#ifdef CONFIG_MANDATORY_FILE_LOCKING static inline bool may_mandlock(void) { -#ifndef CONFIG_MANDATORY_FILE_LOCKING - return false; -#endif return capable(CAP_SYS_ADMIN); } +#else +static inline bool may_mandlock(void) +{ + pr_warn("VFS: \"mand\" mount option not supported"); + return false; +} +#endif /* * Now umount can handle mount points as well as block devices. -- cgit