From 8366025eb80dfa0d8d94b286d53027081c280ef1 Mon Sep 17 00:00:00 2001 From: Dave Hansen Date: Fri, 15 Feb 2008 14:37:30 -0800 Subject: [PATCH] r/o bind mounts: stub functions This patch adds two function mnt_want_write() and mnt_drop_write(). These are used like a lock pair around and fs operations that might cause a write to the filesystem. Before these can become useful, we must first cover each place in the VFS where writes are performed with a want/drop pair. When that is complete, we can actually introduce code that will safely check the counts before allowing r/w<->r/o transitions to occur. Acked-by: Serge Hallyn Acked-by: Al Viro Signed-off-by: Christoph Hellwig Signed-off-by: Andrew Morton Signed-off-by: Dave Hansen Signed-off-by: Al Viro --- include/linux/mount.h | 3 +++ 1 file changed, 3 insertions(+) (limited to 'include') diff --git a/include/linux/mount.h b/include/linux/mount.h index 5ee2df217cd..2eecd2c8c76 100644 --- a/include/linux/mount.h +++ b/include/linux/mount.h @@ -71,9 +71,12 @@ static inline struct vfsmount *mntget(struct vfsmount *mnt) return mnt; } +extern int mnt_want_write(struct vfsmount *mnt); +extern void mnt_drop_write(struct vfsmount *mnt); extern void mntput_no_expire(struct vfsmount *mnt); extern void mnt_pin(struct vfsmount *mnt); extern void mnt_unpin(struct vfsmount *mnt); +extern int __mnt_is_readonly(struct vfsmount *mnt); static inline void mntput(struct vfsmount *mnt) { -- cgit v1.2.3