Re: [PATCH] direct-io: Fix negative return from dio read beyond eof
[Posted January 27, 2016 by corbet]
| From: |
| Avi Kivity <avi-AT-scylladb.com> |
| To: |
| Greg KH <greg-AT-kroah.com> |
| Subject: |
| Re: [PATCH] direct-io: Fix negative return from dio read beyond eof |
| Date: |
| Wed, 27 Jan 2016 19:16:32 +0200 |
| Message-ID: |
| <56A8FB70.6040803@scylladb.com> |
| Cc: |
| Jan Kara <jack-AT-suse.cz>, axboe-AT-kernel.dk, linux-fsdevel-AT-vger.kernel.org, Jeff Moyer <jmoyer-AT-redhat.com>, stable-AT-vger.kernel.org, Steven Whitehouse <swhiteho-AT-redhat.com> |
| Archive‑link: | |
Article |
On 01/27/2016 07:13 PM, Greg KH wrote:
> On Wed, Jan 27, 2016 at 12:38:14PM +0200, Avi Kivity wrote:
>> On 11/19/2015 10:25 PM, Jan Kara wrote:
>>> Assume a filesystem with 4KB blocks. When a file has size 1000 bytes and
>>> we issue direct IO read at offset 1024, blockdev_direct_IO() reads the
>>> tail of the last block and the logic for handling short DIO reads in
>>> dio_complete() results in a return value -24 (1000 - 1024) which
>>> obviously confuses userspace.
>>>
>>> Fix the problem by bailing out early once we sample i_size and can
>>> reliably check that direct IO read starts beyond i_size.
>>>
>>> Reported-by: Avi Kivity <avi@scylladb.com>
>>> Fixes: 9fe55eea7e4b444bafc42fa0000cc2d1d2847275
>>> CC: stable@vger.kernel.org
>> While this patch made it into upstream, it did not appear in 4.3.4. Did it
>> slip through the proverbial cracks? Can it be queued for 4.3.5?
> There are over 400 patches right now in my queue that haven't made it
> into a 4.3.x kernel.
Many projects would consider 400 patches a major release, and here they
are behind two dots...
> These are in the queue, in good company :)
>
> I'll go dig these out as I guess people care about them more than
> others...
>
>
Much appreciated.
