From da15e54c23f4708dd7550bb6478469da311de804 Mon Sep 17 00:00:00 2001
From: Zygmunt Krynicki <zygmunt.krynicki@canonical.com>
Date: Tue, 31 Jan 2017 17:24:45 +0100
Subject: [PATCH] fs: store MS_BIND as MNT_BIND and show it in mountinfo
This patch adds a new MNT_ flag that is set for bind mounts (it mirrors
MS_BIND) and surfaces it via mountinfo. This allows for easier
identification of mount entries that are bind mounted from somewhere
else.
Signed-off-by: Zygmunt Krynicki <zygmunt.krynicki@canonical.com>
---
fs/namespace.c | 1 +
fs/proc_namespace.c | 1 +
include/linux/mount.h | 3 ++-
3 files changed, 4 insertions(+), 1 deletion(-)
diff --git a/fs/namespace.c b/fs/namespace.c
index c9ba9d1..e2fc0c1 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -2162,6 +2162,7 @@ static int do_loopback(struct path *path, const char *old_name,
}
mnt->mnt.mnt_flags &= ~MNT_LOCKED;
+ mnt->mnt.mnt_flags |= MNT_BIND;
err = graft_tree(mnt, parent, mp);
if (err) {
diff --git a/fs/proc_namespace.c b/fs/proc_namespace.c
index 876459559..e510585 100644
--- a/fs/proc_namespace.c
+++ b/fs/proc_namespace.c
@@ -67,6 +67,7 @@ static void show_mnt_opts(struct seq_file *m, struct vfsmount *mnt)
{ MNT_NOATIME, ",noatime" },
{ MNT_NODIRATIME, ",nodiratime" },
{ MNT_RELATIME, ",relatime" },
+ { MNT_BIND, ",bind" },
{ 0, NULL }
};
const struct proc_fs_info *fs_infop;
diff --git a/include/linux/mount.h b/include/linux/mount.h
index 1172cce..71d5ba3 100644
--- a/include/linux/mount.h
+++ b/include/linux/mount.h
@@ -48,7 +48,7 @@ struct mnt_namespace;
#define MNT_ATIME_MASK (MNT_NOATIME | MNT_NODIRATIME | MNT_RELATIME )
#define MNT_INTERNAL_FLAGS (MNT_SHARED | MNT_WRITE_HOLD | MNT_INTERNAL | \
- MNT_DOOMED | MNT_SYNC_UMOUNT | MNT_MARKED)
+ MNT_DOOMED | MNT_SYNC_UMOUNT | MNT_MARKED | MNT_BIND)
#define MNT_INTERNAL 0x4000
@@ -62,6 +62,7 @@ struct mnt_namespace;
#define MNT_SYNC_UMOUNT 0x2000000
#define MNT_MARKED 0x4000000
#define MNT_UMOUNT 0x8000000
+#define MNT_BIND 0x10000000
struct vfsmount {
struct dentry *mnt_root; /* root of the mounted tree */
--
2.7.4