From: Qu Wenruo <quwenruo.btrfs@gmx.com>
To: DanglingPointer <danglingpointerexception@gmail.com>,
Chris Murphy <lists@colorremedies.com>
Cc: Btrfs BTRFS <linux-btrfs@vger.kernel.org>
Subject: Re: migrating to space_cache=2 and btrfs userspace commands
Date: Wed, 14 Jul 2021 15:07:02 +0800 [thread overview]
Message-ID: <5e621c16-2582-a2e0-01c8-c4cbb82dbefd@gmx.com> (raw)
In-Reply-To: <1333ad7a-941d-aead-6e5f-06e321c84feb@gmail.com>
On 2021/7/14 下午2:54, DanglingPointer wrote:
> Yep that's what I'm referring to here:
> https://btrfs.wiki.kernel.org/index.php/Manpage/btrfs(5)
>
> Thanks for the prompt respone Qu!
>
> So just to confirm, our scheduled cron jobs to scrub will still work
> with space_cache=v2?
Yep. No worry.
Just to be more accurate, btrfs-progs has two parts:
- Ioctl related part
Things like "scrub", "subvolume", "filesystem", "device" and etc are
all ioctl related commands.
They just call kernel ioctls to do the job.
For those commands, they are way more independent, and seldomly get
affected by btrfs-progs version.
- Offline read/write part
Things like "mkfs.btrfs", "btrfs check", "btrfs-convert" are the main
commands in this part.
They relies on the btrfs-progs implementation on how to read/write
btrfs.
That's why we always recommend the latest btrfs-progs for "btrfs
check".
Thanks,
Qu
>
>
>
> On 14/7/21 4:05 pm, Qu Wenruo wrote:
>>
>>
>> On 2021/7/14 下午1:44, Chris Murphy wrote:
>>> On Tue, Jul 13, 2021 at 10:59 PM Qu Wenruo <quwenruo.btrfs@gmx.com>
>>> wrote:
>>>>
>>>>
>>>>
>>>> On 2021/7/13 下午11:38, DanglingPointer wrote:
>>>
>>>>> 2. If we use space_cache=v2, is it indeed still the case that the
>>>>> "btrfs" command will NOT work with the filesystem?
>>>>
>>>> Why would you think "btrfs" won't work on a btrfs?
>>>>
>>>
>>> Maybe this?
>>>
>>> man 5 btrfs, space_cache includes:
>>>
>>> The btrfs(8) command currently only has read-only support for v2. A
>>> read-write command may be run on a v2 filesystem by clearing the
>>> cache, running the command, and then remounting with space_cache=v2.
>>>
>>
>> Oh, that's only for offline tools writing into the fs, namingly "btrfs
>> check --repair" and "mkfs.btrfs -R"
>>
>> And I believe that sentence is now out-of-date after btrfs-progs v4.19,
>> which pulls all the support for write time free space tree (v2 space
>> cache).
>>
>> I'll soon send out a patch to fix that.
>>
>> Thanks,
>> Qu
next prev parent reply other threads:[~2021-07-14 7:07 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-13 15:38 migrating to space_cache=2 and btrfs userspace commands DanglingPointer
2021-07-14 4:59 ` Qu Wenruo
2021-07-14 5:44 ` Chris Murphy
2021-07-14 6:05 ` Qu Wenruo
2021-07-14 6:54 ` DanglingPointer
2021-07-14 7:07 ` Qu Wenruo [this message]
2021-07-14 7:18 ` DanglingPointer
2021-07-14 7:45 ` Qu Wenruo
2021-07-15 16:40 ` DanglingPointer
2021-07-15 22:13 ` Qu Wenruo
2021-07-15 17:51 ` Joshua
2021-07-16 12:42 ` DanglingPointer
2021-07-16 12:59 ` Qu Wenruo
2021-07-16 13:23 ` DanglingPointer
2021-07-16 20:33 ` Joshua Villwock
2021-07-16 23:00 ` Qu Wenruo
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