linux-kernel - Re: linux-next: Tree for Feb 4

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Date:	Fri, 6 Feb 2015 16:24:13 +0100
From:	Sedat Dilek <sedat.dilek@...il.com>
To:	"Martin K. Petersen" <martin.petersen@...cle.com>
Cc:	Jens Axboe <axboe@...nel.dk>,
	Stephen Rothwell <sfr@...b.auug.org.au>,
	linux-next <linux-next@...r.kernel.org>,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: linux-next: Tree for Feb 4

On Thu, Feb 5, 2015 at 8:46 PM, Sedat Dilek <sedat.dilek@...il.com> wrote:
> On Thu, Feb 5, 2015 at 4:17 AM, Martin K. Petersen
> <martin.petersen@...cle.com> wrote:
>>>>>>> "Sedat" == Sedat Dilek <sedat.dilek@...il.com> writes:
>>
>> Sedat> No, but I am here on a so-called WUBI installation which
>> Sedat> triggered some bugs being an exotic installation.  My
>> Sedat> Ubuntu/precise is a 18GiB image laying on my Win7 partition
>> Sedat> (/dev/sda2).
>>
>> I've been mulling over this for a while and can't come up with a good
>> approach. So let's just nuke these warnings.
>>
>> --
>> Martin K. Petersen      Oracle Linux Engineering
>>
>>
>> block: Quiesce zeroout wrapper
>>
>> blkdev_issue_zeroout() printed a warning if a device failed a discard or
>> write same request despite advertising support for these. That's fine
>> for SCSI since we'll disable these commands if we get an error back from
>> the disk saying that they are not supported. And consequently the
>> warning only gets printed once.
>>
>> There are other types of block devices that support discard, however,
>> and these may return -EOPNOTSUPP for each command but leave discard
>> enabled in the queue limits. This will cause a warning message for every
>> blkdev_issue_zeroout() invocation.
>>
>> Remove the offending warning messages.
>>
>> Reported-by: Sedat Dilek <sedat.dilek@...il.com>
>> Signed-off-by: Martin K. Petersen <martin.petersen@...cle.com>
>> ---
>>  block/blk-lib.c |   26 +++++++-------------------
>>  1 file changed, 7 insertions(+), 19 deletions(-)
>>
>> diff --git a/block/blk-lib.c b/block/blk-lib.c
>> index 715e948f58a4..7688ee3f5d72 100644
>> --- a/block/blk-lib.c
>> +++ b/block/blk-lib.c
>> @@ -286,7 +286,6 @@ static int __blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
>>   * @discard:   whether to discard the block range
>>   *
>>   * Description:
>> -
>>   *  Zero-fill a block range.  If the discard flag is set and the block
>>   *  device guarantees that subsequent READ operations to the block range
>>   *  in question will return zeroes, the blocks will be discarded. Should
>> @@ -303,26 +302,15 @@ int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
>>                          sector_t nr_sects, gfp_t gfp_mask, bool discard)
>>  {
>>         struct request_queue *q = bdev_get_queue(bdev);
>> -       unsigned char bdn[BDEVNAME_SIZE];
>> -
>> -       if (discard && blk_queue_discard(q) && q->limits.discard_zeroes_data) {
>>
>> -               if (!blkdev_issue_discard(bdev, sector, nr_sects, gfp_mask, 0))
>> -                       return 0;
>> -
>> -               bdevname(bdev, bdn);
>> -               pr_warn("%s: DISCARD failed. Manually zeroing.\n", bdn);
>> -       }
>> +       if (discard && blk_queue_discard(q) && q->limits.discard_zeroes_data &&
>> +           blkdev_issue_discard(bdev, sector, nr_sects, gfp_mask, 0) == 0)
>> +               return 0;
>>
>> -       if (bdev_write_same(bdev)) {
>> -
>> -               if (!blkdev_issue_write_same(bdev, sector, nr_sects, gfp_mask,
>> -                                            ZERO_PAGE(0)))
>> -                       return 0;
>> -
>> -               bdevname(bdev, bdn);
>> -               pr_warn("%s: WRITE SAME failed. Manually zeroing.\n", bdn);
>> -       }
>> +       if (bdev_write_same(bdev) &&
>> +           blkdev_issue_write_same(bdev, sector, nr_sects, gfp_mask,
>> +                                   ZERO_PAGE(0)) == 0)
>> +               return 0;
>>
>>         return __blkdev_issue_zeroout(bdev, sector, nr_sects, gfp_mask);
>>  }
>
> Martin, will you send a separate patch for that?
>
> Thanks.
>

Just for the sake of completeness, the patch is now in block-next:

commit 9f9ee1f2b2f94f19437ae2def7c0d6636d7fe02e
"block: Quiesce zeroout wrapper"

- Sedat -

[1] http://git.kernel.org/cgit/linux/kernel/git/axboe/linux-block.git/commit/?h=for-next&id=9f9ee1f2b2f94f19437ae2def7c0d6636d7fe02e
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