Re: [PATCH 01/34] namespace: take lock_mount_hash() directly when changing flags

Christoph Hellwig
2020-11-03T13:23:59Z

> index cebaa3e81794..20ee291a7af4 100644
> --- a/fs/namespace.c
> +++ b/fs/namespace.c
> @@ -463,7 +463,6 @@ static int mnt_make_readonly(struct mount *mnt)
> {
> int ret = 0;
>
> - lock_mount_hash();

What about adding a lockdep_assert_lock_held in all the functions
that used to take the lock to document the assumptions?

> static int __mnt_unmake_readonly(struct mount *mnt)
> {
> - lock_mount_hash();
> mnt->mnt.mnt_flags &= ~MNT_READONLY;
> - unlock_mount_hash();
> return 0;

This helper is rather pointless now.

> static void set_mount_attributes(struct mount *mnt, unsigned int mnt_flags)
> {
> - lock_mount_hash();
> mnt_flags |= mnt->mnt.mnt_flags & ~MNT_USER_SETTABLE_MASK;
> mnt->mnt.mnt_flags = mnt_flags;
> touch_mnt_namespace(mnt->mnt_ns);
> - unlock_mount_hash();

In linux-next there is an additional notify_mount after the unlock here.

Also while you touch this lock_mount_hash/unlock_mount_hash could be
moved to namespace.c and maked static now.