Re: [PATCH] direct-io: Fix negative return from dio read beyond eof

[Jens Axboe <axboe@kernel.dk>]

On 11/30/2015 06:10 AM, Jan Kara wrote:
> On Thu 19-11-15 21:25:34, 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
>> CC: Steven Whitehouse <swhiteho@redhat.com>
>> Signed-off-by: Jan Kara <jack@suse.cz>
>> ---
>>   fs/direct-io.c | 10 +++++++++-
>>   1 file changed, 9 insertions(+), 1 deletion(-)
>>
>> Avi, this patch fixes the issue for me.
>
> Jens, can you pick up this fix please? Thanks!

Yup, added for 4.4, thanks!

-- 
Jens Axboe