On Sat, Jan 11, 2020 at 07:41:51AM +0800, Anand Jain wrote:
> >> if (device->bdev != path_bdev) {
> >> bdput(path_bdev);
> >> mutex_unlock(&fs_devices->device_list_mutex);
> >> - btrfs_warn_in_rcu(device->fs_info,
> >> - "duplicate device fsid:devid for %pU:%llu old:%s new:%s",
> >> + rcu_read_lock();
> >> + printk_ratelimited(
> >
> > Avoiding fs_info here is correct but we don't want to use raw printk or
> > printk_ratelimited anywhere.
> >
>
> I think I discussed this a long time back, that we should rather pass
> fs_devices in btrfs_warn_in_rcu().
>
> I am ok to make such a change, are you ok?
No, this does not sound right at all. Why should be btrfs_warn_in_rcu
special from the other message callbacks? We need to fix one context, so
let's find something less hacky.
> Or I wonder if there is
> any other way?
We could add a fs_info stub that will get recognized in btrfs_printk.
Eg.
#define NO_FS_INFO ((void*)0x1)
btrfs_printk() {
if (fs_info == NULL)
devname = "<unknown>";
else if (fs_info == NO_FS_INFO)
devname = "...";
else
devname = fs_info->sb->sb_id;
