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From:   Christian Brauner <christian.brauner@ubuntu.com>
To:     viro@zeniv.linux.org.uk, tglx@linutronix.de,
        kstewart@linuxfoundation.org, gregkh@linuxfoundation.org,
        pombredanne@nexb.com, linux-fsdevel@vger.kernel.org,
        linux-kernel@vger.kernel.org, serge@hallyn.com
Cc:     Christian Brauner <christian.brauner@ubuntu.com>
Subject: [PATCH 4/6] statfs: add ST_SHARED
Date:   Fri, 13 Apr 2018 18:11:24 +0200
Message-Id: <20180413161126.31313-5-christian.brauner@ubuntu.com>
In-Reply-To: <20180413161126.31313-1-christian.brauner@ubuntu.com>
References: <20180413161126.31313-1-christian.brauner@ubuntu.com>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

This lets userspace query whether a mountpoint was made MS_SHARED.

Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
---
 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