From: Omar Sandoval <osandov@osandov.com>
To: Nikolay Borisov <nborisov@suse.com>
Cc: linux-btrfs@vger.kernel.org, Jeff Mahoney <jeffm@suse.com>,
kernel-team@fb.com
Subject: Re: [PATCH] Btrfs: fix early ENOSPC due to delalloc
Date: Sat, 15 Jul 2017 00:09:42 -0700 [thread overview]
Message-ID: <20170715070942.GA10038@vader> (raw)
In-Reply-To: <1b7c8283-b585-27c4-6b95-12e889b3b96f@suse.com>
On Sat, Jul 15, 2017 at 09:43:18AM +0300, Nikolay Borisov wrote:
>
>
> On 15.07.2017 00:36, Omar Sandoval wrote:
> > On Thu, Jul 06, 2017 at 10:59:27PM -0700, Omar Sandoval wrote:
> >> From: Omar Sandoval <osandov@fb.com>
> >>
> >> If a lot of metadata is reserved for outstanding delayed allocations, we
> >> rely on shrink_delalloc() to reclaim metadata space in order to fulfill
> >> reservation tickets. However, shrink_delalloc() has a shortcut where if
> >> it determines that space can be overcommitted, it will stop early. This
> >> made sense before the ticketed enospc system, but now it means that
> >> shrink_delalloc() will often not reclaim enough space to fulfill any
> >> tickets, leading to an early ENOSPC. (Reservation tickets don't care
> >> about being able to overcommit, they need every byte accounted for.)
> >>
> >> Fix it by getting rid of the shortcut so that shrink_delalloc() reclaims
> >> all of the metadata it is supposed to. This fixes early ENOSPCs we were
> >> seeing when doing a btrfs receive to populate a new filesystem.
> >
> > Jeff, Nikolay, did either of you get a chance to test this yet?
>
> I tested this patch with generic/273 and it didn't prevent ENOSPC there.
Weird, I've never seen generic/273 fail. Anyways, I'm more interested in
the installer ENOSPCs Jeff mentioned.
next prev parent reply other threads:[~2017-07-15 7:09 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-07-07 5:59 [PATCH] Btrfs: fix early ENOSPC due to delalloc Omar Sandoval
2017-07-14 21:36 ` Omar Sandoval
2017-07-15 6:43 ` Nikolay Borisov
2017-07-15 7:09 ` Omar Sandoval [this message]
2017-07-15 10:35 ` Nikolay Borisov
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