[PATCH] introduce shared mounts

This creates shared mounts.  A shared mount when bind-mounted to some
mountpoint, propagates mount/umount events to each other.  All the
shared mounts that propagate events to each other belong to the same
peer-group.

Signed-off-by: Ram Pai <linuxram@us.ibm.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 4 insertions, 0 deletions

diff --git a/fs/pnode.h b/fs/pnode.h
index 33549a3a74e..ab1bdaee4e0 100644
--- a/fs/pnode.h
+++ b/fs/pnode.h
@@ -10,5 +10,9 @@
 
 #include <linux/list.h>
 #include <linux/mount.h>
+
+#define IS_MNT_SHARED(mnt) (mnt->mnt_flags & MNT_SHARED)
+#define CLEAR_MNT_SHARED(mnt) (mnt->mnt_flags &= ~MNT_SHARED)
+
 void change_mnt_propagation(struct vfsmount *, int);
 #endif /* _LINUX_PNODE_H */