initmpfs: replace MS_NOUSER in initramfs
Mounting MS_NOUSER prevents --bind mounts from rootfs. Prevent new rootfs
mounts with a different mechanism that doesn't affect bind mounts.
Signed-off-by: Rob Landley <rob@landley.net>
Cc: Jeff Layton <jlayton@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Stephen Warren <swarren@nvidia.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Jim Cromie <jim.cromie@gmail.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/ramfs/inode.c b/fs/ramfs/inode.c
index c24f1e1..8f7fe32 100644
--- a/fs/ramfs/inode.c
+++ b/fs/ramfs/inode.c
@@ -247,7 +247,12 @@
static struct dentry *rootfs_mount(struct file_system_type *fs_type,
int flags, const char *dev_name, void *data)
{
- return mount_nodev(fs_type, flags|MS_NOUSER, data, ramfs_fill_super);
+ static unsigned long once;
+
+ if (test_and_set_bit(1, &once))
+ return ERR_PTR(-ENODEV);
+
+ return mount_nodev(fs_type, flags, data, ramfs_fill_super);
}
static void ramfs_kill_sb(struct super_block *sb)