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* bcachefs-tools: O_DIRECT necessary?
@ 2022-10-31  1:18 Thomas Weißschuh
  2022-10-31  1:41 ` Kent Overstreet
  0 siblings, 1 reply; 3+ messages in thread
From: Thomas Weißschuh @ 2022-10-31  1:18 UTC (permalink / raw)
  To: linux-bcache

Hi all,

I just tried to run the unittests of bcachefs-tools and they are failing for
me.
The culprit is that mkfs.bcachefs tries to open the disk image with O_DIRECT
which is not allowed on tmpfs.

Is O_DIRECT really necessary for mkfs? It does not seem necessary for other
filesystems.

Thomas

^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: bcachefs-tools: O_DIRECT necessary?
  2022-10-31  1:18 bcachefs-tools: O_DIRECT necessary? Thomas Weißschuh
@ 2022-10-31  1:41 ` Kent Overstreet
  2022-10-31  3:10   ` Thomas Weißschuh
  0 siblings, 1 reply; 3+ messages in thread
From: Kent Overstreet @ 2022-10-31  1:41 UTC (permalink / raw)
  To: Thomas Weißschuh; +Cc: linux-bcache, linux-bcachefs

On Mon, Oct 31, 2022 at 02:18:40AM +0100, Thomas Weißschuh wrote:
> Hi all,
> 
> I just tried to run the unittests of bcachefs-tools and they are failing for
> me.
> The culprit is that mkfs.bcachefs tries to open the disk image with O_DIRECT
> which is not allowed on tmpfs.
> 
> Is O_DIRECT really necessary for mkfs? It does not seem necessary for other
> filesystems.

Hey - the proper mailing list for bcachefs is linux-bcachefs@vger.kernel.org now
:)

It's not strictly necessary, we use O_DIRECT because we're emulating the kernel
bio interface. There are other situations where this has been a problem though,
we need to add either a flag to use buffered IO or preferably a way to
automatically fall back to buffered IO.

Could you open a bug for this? I'll try to get to it in the near future

https://github.com/koverstreet/bcachefs/issues/

Cheers,
Kent

^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: bcachefs-tools: O_DIRECT necessary?
  2022-10-31  1:41 ` Kent Overstreet
@ 2022-10-31  3:10   ` Thomas Weißschuh
  0 siblings, 0 replies; 3+ messages in thread
From: Thomas Weißschuh @ 2022-10-31  3:10 UTC (permalink / raw)
  To: Kent Overstreet; +Cc: linux-bcache, linux-bcachefs

On 2022-10-30 21:41-0400, Kent Overstreet wrote:
> On Mon, Oct 31, 2022 at 02:18:40AM +0100, Thomas Weißschuh wrote:
> > Hi all,
> > 
> > I just tried to run the unittests of bcachefs-tools and they are failing for
> > me.
> > The culprit is that mkfs.bcachefs tries to open the disk image with O_DIRECT
> > which is not allowed on tmpfs.
> > 
> > Is O_DIRECT really necessary for mkfs? It does not seem necessary for other
> > filesystems.
> 
> Hey - the proper mailing list for bcachefs is linux-bcachefs@vger.kernel.org now
> :)

My bad, I copied the wrong list from one of your mails.

> It's not strictly necessary, we use O_DIRECT because we're emulating the kernel
> bio interface. There are other situations where this has been a problem though,
> we need to add either a flag to use buffered IO or preferably a way to
> automatically fall back to buffered IO.
> 
> Could you open a bug for this? I'll try to get to it in the near future
> 
> https://github.com/koverstreet/bcachefs/issues/

I opened it in the tools repo because those are broken:
https://github.com/koverstreet/bcachefs-tools/issues/132

Thomas

^ permalink raw reply	[flat|nested] 3+ messages in thread

end of thread, other threads:[~2022-10-31  3:10 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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2022-10-31  1:18 bcachefs-tools: O_DIRECT necessary? Thomas Weißschuh
2022-10-31  1:41 ` Kent Overstreet
2022-10-31  3:10   ` Thomas Weißschuh

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