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Subject: Re: [BUG] btrfs potential failure on 32 core LTP test (fallocate05)
To:     Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>,
        Chris Mason <clm@fb.com>, David Sterba <dsterba@suse.com>,
        linux-btrfs@vger.kernel.org,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        "kernel-team@lists.ubuntu.com" <kernel-team@lists.ubuntu.com>,
        "ltp@lists.linux.it" <ltp@lists.linux.it>,
        Qu Wenruo <wqu@suse.com>, Filipe Manana <fdmanana@suse.com>
References: <a3b42abc-6996-ab06-ea9f-238e7c6f08d7@canonical.com>
From:   Josef Bacik <josef@toxicpanda.com>
Message-ID: <e4c71c01-ed70-10a6-be4d-11966d1fcb75@toxicpanda.com>
Date:   Tue, 29 Jun 2021 13:20:40 -0400
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On 6/29/21 1:00 PM, Krzysztof Kozlowski wrote:
> Dear BTRFS folks,
> 
> I am hitting a potential regression of btrfs, visible only with
> fallocate05 test from LTP (Linux Test Project) only on 32+ core Azure
> instances (x86_64).
> 
> Tested:
> v5.8 (Ubuntu with our stable patches): PASS
> v5.11 (Ubuntu with our stable patches): FAIL
> v5.13 mainline: FAIL
> 
> PASS means test passes on all instances
> FAIL means test passes on other instance types (e.g. 4 or 16 core) but
> fails on 32 and 64 core instances (did not test higher),
> e.g.: Standard_F32s_v2, Standard_F64s_v2, Standard_D32s_v3,
> Standard_E32s_v3
> 
> Reproduction steps:
> git clone https://github.com/linux-test-project/ltp.git
> cd ltp
> ./build.sh && make install -j8
> cd ../ltp-install
> sudo ./runltp -f syscalls -s fallocate05
> 

This thing keeps trying to test ext2, how do I make it only test btrfs?  Thanks,

Josef