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Subject: Re: Bug?: unlink cause btrfs error but other fs don't
To:     <linux-btrfs@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        Nikolay Borisov <nborisov@suse.com>
References: <49edadc4-9191-da89-3e3b-ca495f582a4d@windriver.com>
CC:     <josef@toxicpanda.com>
From:   "Hongzhi, Song" <hongzhi.song@windriver.com>
Message-ID: <bbdb613c-020b-03ec-c218-57299c3f6b29@windriver.com>
Date:   Wed, 4 Sep 2019 16:39:49 +0800
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Hi Nikolay,

 >

There were multiple fixes from Josef recently improving btrfs enospc
handling with tiny filesystems (which is generally not the targeted use
case of btrfs). The code lives in
https://github.com/kdave/btrfs-devel/commits/misc-next  should you want
to test it. Otherwise re-test after next merge windows when those
patches are supposed to be merged for 5.4

 >


Thank for your reply, I will keep eyes on the branch.

ps: this email is my simply testcase from ltp


--Hongzhi


On 9/4/19 4:02 PM, Hongzhi, Song wrote:
> Hi ,
>
>
> *Kernel:*
>
>     After v5.2-rc1, qemux86-64
>
>     make -j40 ARCH=x86_64 CROSS_COMPILE=x86-64-gcc
>     use qemu to bootup kernel
>
>
> *Reproduce:*
>
>     There is a test case failed on btrfs but success on other 
> fs(ext4,ext3), see attachment.
>
>
>     Download attachments:
>
>         gcc test.c -o myout -Wall -lpthread
>
>         copy myout and run.sh to your qemu same directory.
>
>         on qemu:
>
>             ./run.sh
>
>
>     I found the block device size with btrfs set 512M will cause the 
> error.
>     256M and 1G all success.
>
>
> *Error info:*
>
>     "BTRFS warning (device loop0): could not allocate space for a 
> delete; will truncate on mount"
>
>
> *Related patch:*
>
>     I use git bisect to find the following patch introduces the issue.
>
>     commit c8eaeac7b734347c3afba7008b7af62f37b9c140
>     Author: Josef Bacik <josef@toxicpanda.com>
>     Date:   Wed Apr 10 15:56:10 2019 -0400
>
>         btrfs: reserve delalloc metadata differently
>         ...
>
>
> Anyone's reply will be appreciated.
>
> --Hongzhi
>