[PATCH 4/6] statfs: add ST_SHARED

From: Christian Brauner
Date: Fri Apr 13 2018 - 12:12:01 EST


This lets userspace query whether a mountpoint was made MS_SHARED.

Signed-off-by: Christian Brauner <christian.brauner@xxxxxxxxxx>
---
fs/statfs.c | 2 ++
include/linux/statfs.h | 1 +
2 files changed, 3 insertions(+)

diff --git a/fs/statfs.c b/fs/statfs.c
index 61b3063d3921..2fc6f9c3793c 100644
--- a/fs/statfs.c
+++ b/fs/statfs.c
@@ -31,6 +31,8 @@ static int flags_by_mnt(int mnt_flags)
flags |= ST_RELATIME;
if (mnt_flags & MNT_UNBINDABLE)
flags |= ST_UNBINDABLE;
+ if (mnt_flags & MNT_SHARED)
+ flags |= ST_SHARED;
return flags;
}

diff --git a/include/linux/statfs.h b/include/linux/statfs.h
index e1b84d0388c1..5416b2936dd9 100644
--- a/include/linux/statfs.h
+++ b/include/linux/statfs.h
@@ -41,5 +41,6 @@ struct kstatfs {
#define ST_NODIRATIME (1<<11) /* do not update directory access times */
#define ST_RELATIME (1<<12) /* update atime relative to mtime/ctime */
#define ST_UNBINDABLE (1<<17) /* change to unbindable */
+#define ST_SHARED (1<<20) /* change to shared */

#endif
--
2.17.0