APPLIED: [PATCH 0/2][SRU][ARTFUL] Fix VFS warning and file system resize failure (LP: #1726818)

[Khaled Elmously]

Applied to artful

On 2017-11-21 17:05:26 , Colin King wrote:
> From: Colin Ian King <colin.king at canonical.com>
> 
> The following two patches fix a VFS warning and a file system resize failure
> on Artful when booting a virtual image using a vagrant/VirtualBox combo.
> 
> [SRU Justfication, Artful]
> 
> [Impact]
> 
> Booting the 4.13 Artful kernel with vagrant using VirtualBox trips the warning:
> 
> [ 61.010337] VFS: brelse: Trying to free free buffer
> [ 61.114875] ------------[ cut here ]------------
> [ 61.114886] WARNING: CPU: 0 PID: 683 at /build/linux-XO_uEE/linux-4.13.0/fs/buffer.c:1205 __brelse+0x21/0x30
> 
> and a failed resize of a partition. The root cause has been bisected down
> to the following commmit:
> 
> commit c20cfc27a47307e811346f85959cf3cc07ae42f9
> Author: Christoph Hellwig <hch at lst.de>
> Date: Wed Apr 5 19:21:07 2017 +0200
> 
>     block: stop using blkdev_issue_write_same for zeroing
> 
> [Fix]
> The Upstream commit directly fixes this issue:
> 
> commit d5ce4c31d6df518dd8f63bbae20d7423c5018a6c
> Author: Ilya Dryomov <idryomov at gmail.com>
> Date: Mon Oct 16 15:59:10 2017 +0200
> 
>     block: cope with WRITE ZEROES failing in blkdev_issue_zeroout()
> 
> ..however we also require a backport of the following upstream commit to apply
> the above commit cleanly:
> 
> commit 425a4dba7953e35ffd096771973add6d2f40d2ed
> Author: Ilya Dryomov <idryomov at gmail.com>
> Date: Mon Oct 16 15:59:09 2017 +0200
> 
>     block: factor out __blkdev_issue_zero_pages()
> 
> [Testscase]
> 
> On Ubuntu Xenial:
> 
> 1. sudo apt-get install virtualbox vagrant
> 2. edit /etc/group and add one's user name to the vboxusers group
> 3. log out log back
> 4. vagrant init ubuntu/artful64
> 5. vagrant up
> 6. vagrant ssh
> 7. dmesg | grep "VFS: brelse"
> 
> without the fix one will see the VFS brelse warning message and the /
> partition will not have been resized.
> 
> with a fixed system there is is no VFS vbrelse warning and / as been
> resized as expected.
> 
> [Regresion potential]
> These patches touch the blk library so potentially it could break the block
> layer and corrupt data on disk. However these are upstream fixes that address
> the buggy commit c20cfc27a47307e811346f85959cf3cc07ae42f9 and are known to
> address the bug.
> 
> Colin Ian King (1):
>   block: factor out __blkdev_issue_zero_pages()
> 
> Ilya Dryomov (1):
>   block: cope with WRITE ZEROES failing in blkdev_issue_zeroout()
> 
>  block/blk-lib.c | 108 +++++++++++++++++++++++++++++++++++++-------------------
>  1 file changed, 72 insertions(+), 36 deletions(-)
> 
> -- 
> 2.7.4
> 
> 
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