[PATCH RFC v2 21/23] nullfs: make nullfs multi-instance

From: Christian Brauner

Date: Thu Mar 05 2026 - 18:41:06 EST


Allow multiple instances of nullfs to be created. Right now we're only
going to use it for kernel-internal purposes but ultimately we can allow
userspace to use it too to e.g., safely overmount stuff.

Signed-off-by: Christian Brauner <brauner@xxxxxxxxxx>
---
fs/nullfs.c | 7 +------
1 file changed, 1 insertion(+), 6 deletions(-)

diff --git a/fs/nullfs.c b/fs/nullfs.c
index fdbd3e5d3d71..88ba4f3fc3a2 100644
--- a/fs/nullfs.c
+++ b/fs/nullfs.c
@@ -40,14 +40,9 @@ static int nullfs_fs_fill_super(struct super_block *s, struct fs_context *fc)
return 0;
}

-/*
- * For now this is a single global instance. If needed we can make it
- * mountable by userspace at which point we will need to make it
- * multi-instance.
- */
static int nullfs_fs_get_tree(struct fs_context *fc)
{
- return get_tree_single(fc, nullfs_fs_fill_super);
+ return get_tree_nodev(fc, nullfs_fs_fill_super);
}

static const struct fs_context_operations nullfs_fs_context_ops = {

--
2.47.3