From: Josef Bacik <josef@toxicpanda.com>
To: Qu Wenruo <wqu@suse.com>, linux-btrfs@vger.kernel.org
Cc: Marc Lehmann <schmorp@schmorp.de>
Subject: Re: [PATCH v2 3/4] btrfs: space-info: Use per-profile available space in can_overcommit()
Date: Thu, 2 Jan 2020 11:18:25 -0500 [thread overview]
Message-ID: <16e4a6d7-23d0-697d-8f2d-69766bd6384c@toxicpanda.com> (raw)
In-Reply-To: <20200102112746.145045-4-wqu@suse.com>
On 1/2/20 6:27 AM, Qu Wenruo wrote:
> For the following disk layout, can_overcommit() can cause false
> confidence in available space:
>
> devid 1 unallocated: 1T
> devid 2 unallocated: 10T
> metadata type: RAID1
>
> As can_overcommit() simply uses unallocated space with factor to
> calculate the allocatable metadata chunk size.
>
> can_overcommit() believes we still have 5.5T for metadata chunks, while
> the truth is, we only have 1T available for metadata chunks.
> This can lead to ENOSPC at run_delalloc_range() and cause transaction
> abort.
>
> Since factor based calculation can't distinguish RAID1/RAID10 and DUP at
> all, we need proper chunk-allocator level awareness to do such estimation.
>
> Thankfully, we have per-profile available space already calculated, just
> use that facility to avoid such false confidence.
>
> Reported-by: Marc Lehmann <schmorp@schmorp.de>
> Signed-off-by: Qu Wenruo <wqu@suse.com>
I don't expect this will change much as you mess with the other code, so you can
go ahead and add
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
To this one, thanks,
Josef
next prev parent reply other threads:[~2020-01-02 16:18 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-02 11:27 [PATCH v2 0/4] Introduce per-profile available space array to avoid over-confident can_overcommit() Qu Wenruo
2020-01-02 11:27 ` [PATCH v2 1/4] btrfs: Introduce per-profile available space facility Qu Wenruo
2020-01-02 16:13 ` Josef Bacik
2020-01-04 6:40 ` kbuild test robot
2020-01-02 11:27 ` [PATCH v2 2/4] btrfs: Update per-profile available space when device size/used space get updated Qu Wenruo
2020-01-02 16:17 ` Josef Bacik
2020-01-03 0:51 ` Qu Wenruo
2020-01-03 9:52 ` Qu Wenruo
2020-01-03 16:35 ` Josef Bacik
2020-01-02 11:27 ` [PATCH v2 3/4] btrfs: space-info: Use per-profile available space in can_overcommit() Qu Wenruo
2020-01-02 16:18 ` Josef Bacik [this message]
2020-01-02 11:27 ` [PATCH v2 4/4] btrfs: statfs: Use virtual chunk allocation to calculation available data space Qu Wenruo
2020-01-02 16:20 ` Josef Bacik
2020-01-03 0:38 ` Qu Wenruo
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