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From: Amir Goldstein <amir73il@gmail.com>
To: Sargun Dhillon <sargun@sargun.me>
Cc: Vivek Goyal <vgoyal@redhat.com>, Jeff Layton <jlayton@redhat.com>,
	linux-fsdevel <linux-fsdevel@vger.kernel.org>,
	overlayfs <linux-unionfs@vger.kernel.org>,
	Miklos Szeredi <miklos@szeredi.hu>
Subject: Re: [PATCH] overlay: Implement volatile-specific fsync error behaviour
Date: Thu, 3 Dec 2020 12:36:36 +0200	[thread overview]
Message-ID: <CAOQ4uxjVvh3b=V=saA96i4U2E=tZWBxH_JJL-HcrfTomSx-hFA@mail.gmail.com> (raw)
In-Reply-To: <20201202184936.GA17139@ircssh-2.c.rugged-nimbus-611.internal>

> > > > How did you finally end up testing the error case. Want to simualate
> > > > error aritificially and test it.
> > > >
>
> I used the blockdev error injection layer. It only works with ext2, because
> ext4 (and other filesystems) will error and go into readonly.
>
> dd if=/dev/zero of=/tmp/loop bs=1M count=100
> losetup /dev/loop8 /tmp/loop
> mkfs.ext2 /dev/loop8
> mount -o errors=continue /dev/loop8 /mnt/loop/
> mkdir -p /mnt/loop/{upperdir,workdir}
> mount -t overlay -o volatile,index=off,lowerdir=/root/lowerdir,upperdir=/mnt/loop/upperdir,workdir=/mnt/loop/workdir none /mnt/foo/
> echo 1 > /sys/block/loop8/make-it-fail
> echo 100 > /sys/kernel/debug/fail_make_request/probability
> echo 1 > /sys/kernel/debug/fail_make_request/times
> dd if=/dev/zero of=/mnt/foo/zero bs=1M count=1
> sync
>
> I tried to get XFS tests working, but I was unable to get a simpler repro than
> above. This is also easy enough to do with a simple kernel module. Maybe it'd be
> neat to be able to inject in errseq increments via the fault injection API one
> day? I have no idea what the VFS's approach here is.
>

Here you go. A simple xfstest:

https://github.com/amir73il/xfstests/commits/ovl-volatile

It passes with check -overlay on xfs/ext4 and it fails if you uncomment
the -o volatile mount option

Just move it to the tests/overlay/ tests and add syncfs (I wasn't sure
about how to do that).

Thanks,
Amir.

  parent reply	other threads:[~2020-12-03 10:37 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-12-02  9:27 [PATCH] overlay: Implement volatile-specific fsync error behaviour Sargun Dhillon
2020-12-02 10:25 ` Amir Goldstein
2020-12-02 15:07 ` Vivek Goyal
2020-12-02 17:02   ` Jeff Layton
2020-12-02 17:29     ` Vivek Goyal
2020-12-02 18:22       ` Jeff Layton
2020-12-02 18:56         ` Vivek Goyal
2020-12-02 19:03           ` Sargun Dhillon
2020-12-02 19:26           ` Jeff Layton
2020-12-02 21:34             ` Vivek Goyal
2020-12-02 21:52               ` Jeff Layton
2020-12-03 10:42                 ` Sargun Dhillon
2020-12-03 12:06                   ` Jeff Layton
2020-12-03 14:27                   ` Vivek Goyal
2020-12-03 15:20                     ` Jeff Layton
2020-12-03 17:08                       ` Sargun Dhillon
2020-12-03 17:50                         ` Jeff Layton
2020-12-03 20:43                           ` Vivek Goyal
2020-12-03 21:36                             ` Jeff Layton
2020-12-03 22:24                               ` Vivek Goyal
2020-12-03 23:36                                 ` Jeff Layton
2020-12-04  6:45                                   ` Amir Goldstein
2020-12-04 15:00                                     ` Vivek Goyal
2020-12-03 20:31                       ` Vivek Goyal
2020-12-02 18:49       ` Sargun Dhillon
2020-12-02 19:10         ` Jeff Layton
2020-12-03 10:36         ` Amir Goldstein [this message]
2020-12-02 17:41   ` Amir Goldstein

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