Re: [PATCH v4 1/6] fs: enhance and rename shutdown() callback to remove_bdev()

Qu Wenruo
2025-07-08T05:42:03Z

在 2025/7/8 14:35, Dave Chinner 写道:
[...]
>>> Not really worthy if we only want a single different behavior.
>
> This is the *3rd* different behaviour for ->mark_dead. We
> have the generic behaviour, the bcachefs behaviour, and now the
> btrfs behaviour (whatever that may be).

Then why not merging the btrfs/bcachefs callback into one generic
callback? Other than introducing 3 different bdev_holder_ops?

This looks exactly the opposite what VFS is trying to do.

Thanks,
Qu

>
>>> Thus I strongly prefer to do with the existing fs_holder_ops, no matter
>>> if it's using/renaming the shutdown() callback, or a new callback.
>>
>> Previously Christoph is against a new ->remove_bdev() callback, as it is
>> conflicting with the existing ->shutdown().
>>
>> So what about a new ->handle_bdev_remove() callback, that we do something
>> like this inside fs_bdev_mark_dead():
>>
>> {
>> bdev_super_lock();
>> if (!surprise)
>> sync_filesystem();
>>
>> if (s_op->handle_bdev_remove) {
>> ret = s_op->handle_bdev_remove();
>> if (!ret) {
>> super_unlock_shared();
>> return;
>> }
>> }
>> shrink_dcache_sb();
>> evict_inodes();
>> if (s_op->shutdown)
>> s_op->shutdown();
>> }
>>
>> So that the new ->handle_bdev_remove() is not conflicting with
>> ->shutdown() but an optional one.
>>
>> And if the fs can not handle the removal, just let
>> ->handle_bdev_remove() return an error so that we fallback to the existing
>> shutdown routine.
>>
>> Would this be more acceptable?
>
> No.
>
> -Dave.