Re: [RFC] Live resize of backing device

[Coly Li <colyli@suse.de>]

> 2023年2月20日 16:27，mingzhe <mingzhe.zou@easystack.cn> 写道：
> 
> 
> 
> 在 2023/2/19 17:39, Coly Li 写道:
>>> 2023年1月27日 20:44，Andrea Tomassetti <andrea.tomassetti-opensource@devo.com> 写道：
>>> 
>>> From 83f490ec8e81c840bdaf69e66021d661751975f2 Mon Sep 17 00:00:00 2001
>>> From: Andrea Tomassetti <andrea.tomassetti-opensource@devo.com>
>>> Date: Thu, 8 Sep 2022 09:47:55 +0200
>>> Subject: [PATCH v2] bcache: Add support for live resize of backing devices
>>> 
>>> Signed-off-by: Andrea Tomassetti <andrea.tomassetti-opensource@devo.com>
>> Hi Andrea,
>> I am fine with this patch and added it in my test queue now. Do you have an updated version, (e.g. more coding refine or adding commit log), then I can update my local version.
>> BTW, it could be better if the patch will be sent out as a separated email.
>> Thanks.
>> Coly Li
> Hi, Coly
> 
> I posted some patchsets about online resize.
> 
> -[PATCH v5 1/3] bcache: add dirty_data in struct bcache_device
> -[PATCH v5 2/3] bcache: allocate stripe memory when partial_stripes_expensive is true
> -[PATCH v5 3/3] bcache: support online resizing of cached_dev
> 
> There are some differences:
> 1. Create /sys/block/bcache0/bcache/size in sysfs to trigger resize
> 2. Allocate stripe memory only if partial_stripes_expensive is true
> 3. Simplify bcache_dev_sectors_dirty()
> 
> Since the bcache superblock uses some sectors, the actual space of the bcache device is smaller than the backing. In order to provide a bcache device with a user-specified size, we need to create a backing device with a larger space, and then resize bcache. So resize can specify the size is very necessary.
> 
> 

Yes, they are in my for-test queue already. I will test both and make a choice.

Thanks.

Coly Li

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