Re: [PATCH] block: don't try Write Same from __blkdev_issue_zeroout

[Jens Axboe]

On 02/05/2017 10:10 AM, Christoph Hellwig wrote:
> Write Same can return an error asynchronously if it turns out the
> underlying SCSI device does not support Write Same, which makes a
> proper fallback to other methods in __blkdev_issue_zeroout impossible.
> Thus only issue a Write Same from blkdev_issue_zeroout an don't try it
> at all from __blkdev_issue_zeroout as a non-invasive workaround.

Thanks, added for 4.10.

-- 
Jens Axboe

Re: [PATCH] block: don't try Write Same from __blkdev_issue_zeroout

[Junichi Nomura]

On 02/06/17 02:10, Christoph Hellwig wrote:
> Write Same can return an error asynchronously if it turns out the
> underlying SCSI device does not support Write Same, which makes a
> proper fallback to other methods in __blkdev_issue_zeroout impossible.
> Thus only issue a Write Same from blkdev_issue_zeroout an don't try it
> at all from __blkdev_issue_zeroout as a non-invasive workaround.
> 
> Signed-off-by: Christoph Hellwig 
> Reported-by: Junichi Nomura 
> Fixes: e73c23ff ("block: add async variant of blkdev_issue_zeroout")

Thank you. I tested your patch and confirmed it works for me.

-- 
Jun'ichi Nomura, NEC Corporation / NEC Solution Innovators, Ltd.

[PATCH] block: don't try Write Same from __blkdev_issue_zeroout

[Christoph Hellwig]

Write Same can return an error asynchronously if it turns out the
underlying SCSI device does not support Write Same, which makes a
proper fallback to other methods in __blkdev_issue_zeroout impossible.
Thus only issue a Write Same from blkdev_issue_zeroout an don't try it
at all from __blkdev_issue_zeroout as a non-invasive workaround.

Signed-off-by: Christoph Hellwig 
Reported-by: Junichi Nomura 
Fixes: e73c23ff ("block: add async variant of blkdev_issue_zeroout")
---
 block/blk-lib.c | 9 -
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/block/blk-lib.c b/block/blk-lib.c
index f8c82a9b4012..ed1e78e24db0 100644
--- a/block/blk-lib.c
+++ b/block/blk-lib.c
@@ -306,11 +306,6 @@ int __blkdev_issue_zeroout(struct block_device *bdev, 
sector_t sector,
if (ret == 0 || (ret && ret != -EOPNOTSUPP))
goto out;
 
-   ret = __blkdev_issue_write_same(bdev, sector, nr_sects, gfp_mask,
-   ZERO_PAGE(0), biop);
-   if (ret == 0 || (ret && ret != -EOPNOTSUPP))
-   goto out;
-
ret = 0;
while (nr_sects != 0) {
bio = next_bio(bio, min(nr_sects, (sector_t)BIO_MAX_PAGES),
@@ -369,6 +364,10 @@ int blkdev_issue_zeroout(struct block_device *bdev, 
sector_t sector,
return 0;
}
 
+   if (!blkdev_issue_write_same(bdev, sector, nr_sects, gfp_mask,
+   ZERO_PAGE(0)))
+   return 0;
+
blk_start_plug();
ret = __blkdev_issue_zeroout(bdev, sector, nr_sects, gfp_mask,
, discard);
-- 
2.11.0