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From: Nick Alcock <nix@esperi.org.uk>
To: Jan Kara <jack@suse.cz>
Cc: linux-ext4@vger.kernel.org,
	Linux FS Mailing List <linux-fsdevel@vger.kernel.org>,
	Eric Biggers <ebiggers@google.com>
Subject: Re: repeatable inline-data oops (and fs corruption) caused by msync() of shared writable mmap (with recipe)
Date: Thu, 16 Mar 2017 16:13:01 +0000	[thread overview]
Message-ID: <8760j95hf6.fsf@esperi.org.uk> (raw)
In-Reply-To: <20170316153100.GA8224@quack2.suse.cz> (Jan Kara's message of "Thu, 16 Mar 2017 16:31:00 +0100")

On 16 Mar 2017, Jan Kara stated:

> On Tue 28-02-17 22:22:25, Nix wrote:
>> I first spotted this -- or it spotted me -- back in the v4.7.x days. It
>> is still present in v4.10.
>> 
>> Here's a replication recipe, given a reasonable rootfs with a compiler
>> on it, and assuming a blank virtio disk on /dev/vdb:
>
> Yup, the problem is that we mmap file with inline data without unpacking
> that and ext4_writepages() is unable to update inline data. Easy fix would
> be to unpack inline data in ext4_page_mkwrite(), somewhat more complicated
> fix would be to unpack inline data when extending file to too large size
> via truncate and handle writing into inode in ext4_writepages(). I'll have
> a look into fixing this. Thanks for report!

You probably want to talk to Eric Biggers, who posted a partial fix a
few days ago: <http://marc.info/?l=linux-ext4&m=148936608506059&w=2>

      reply	other threads:[~2017-03-16 16:13 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-02-28 22:22 repeatable inline-data oops (and fs corruption) caused by msync() of shared writable mmap (with recipe) Nix
2017-03-16 15:31 ` Jan Kara
2017-03-16 16:13   ` Nick Alcock [this message]

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