From: Andrei Borzenkov <arvidjaar@gmail.com>
To: NeilBrown <neilb@suse.de>, Bart Van Assche <bvanassche@acm.org>
Cc: Martin Steigerwald <martin@lichtvoll.de>,
linux-block@vger.kernel.org, linux-btrfs@vger.kernel.org
Subject: Re: Assumption on fixed device numbers in Plasma's desktop search Baloo
Date: Sat, 26 Jun 2021 09:14:08 +0300 [thread overview]
Message-ID: <7d12d49d-1dbf-566e-cb92-84e68ab67e23@gmail.com> (raw)
In-Reply-To: <162468466604.26869.10474422208964999454@noble.neil.brown.name>
On 26.06.2021 08:17, NeilBrown wrote:
> On Sat, 26 Jun 2021, Bart Van Assche wrote:
>> On 6/25/21 5:54 PM, NeilBrown wrote:
>>> On Sat, 26 Jun 2021, Martin Steigerwald wrote:
>>>> And that Baloo needs an "invariant" for
>>>> a file. See comment #11 of that bug report:
>>>
>>> That is really hard to provide in general. Possibly the best approach
>>> is to use the statfs() systemcall to get the "f_fsid" field. This is
>>> 64bits. It is not supported uniformly well by all filesystems, but I
>>> think it is at least not worse than using the device number. For a lot
>>> of older filesystems it is just an encoding of the device number.
>>>
>>> For btrfs, xfs, ext4 it is much much better.
>>
>> How about combining the UUID of the partition with the file path? An
>> example from one of the VMs on my workstation:
>
> A btrfs filesystem can span multiple partitions, and those partitions
> can be added and removed dynamically. So you could migrated from one to
> another.
>
I suspect it was intended to be "filesytemm UUID". At least that is the
field in lsblk output that was referenced.
> f_fsid really is best for any modern filesystem.
>
> NeilBrown
>
next prev parent reply other threads:[~2021-06-26 6:14 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-25 19:06 Assumption on fixed device numbers in Plasma's desktop search Baloo Martin Steigerwald
2021-06-26 0:27 ` Qu Wenruo
2021-06-26 8:49 ` Martin Steigerwald
2021-06-26 9:33 ` Qu Wenruo
2021-06-26 10:18 ` Martin Steigerwald
2021-06-26 0:54 ` NeilBrown
2021-06-26 3:38 ` Bart Van Assche
2021-06-26 5:17 ` NeilBrown
2021-06-26 6:14 ` Andrei Borzenkov [this message]
2021-06-26 6:24 ` Qu Wenruo
2021-06-26 8:51 ` Martin Steigerwald
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