[PATCH 1/5] initmpfs: replace MS_NOUSER in initramfs

From: Rob Landley
Date: Sat Jun 29 2013 - 16:12:21 EST


From: Rob Landley <rob@xxxxxxxxxxx>

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@xxxxxxxxxxx>
---

fs/ramfs/inode.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/fs/ramfs/inode.c b/fs/ramfs/inode.c
index c24f1e1..14b9c35 100644
--- a/fs/ramfs/inode.c
+++ b/fs/ramfs/inode.c
@@ -247,7 +247,14 @@ struct dentry *ramfs_mount(struct file_system_type *fs_type,
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 int once;
+
+ if (once)
+ return ERR_PTR(-ENODEV);
+ else
+ once++;
+
+ return mount_nodev(fs_type, flags, data, ramfs_fill_super);
}

static void ramfs_kill_sb(struct super_block *sb)
--
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