[PATCH] NVMe: Format fix when going from 4k sector size to 512 bytes

[PATCH] NVMe: Format fix when going from 4k sector size to 512 bytes

[Jeff Lien]

If you format a device with a 4k sector size back to 512 bytes,
the queue limit values for physical block size and IO sizes were
not getting updated; only the logical block size was being
updated.  This patch adds code to update the physical block
and IO sizes.

Signed-off-by: Jeff Lien <jeff.lien at wdc.com>
---
 drivers/nvme/host/core.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index f837d666cbd4..035ed9e57f70 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -1336,6 +1336,7 @@ static void nvme_update_disk_info(struct gendisk *disk,
 {
 	sector_t capacity = le64_to_cpup(&id->nsze) << (ns->lba_shift - 9);
 	unsigned stream_alignment = 0;
+	unsigned short bs;
 
 	if (ns->ctrl->nr_streams && ns->sws && ns->sgs)
 		stream_alignment = ns->sws * ns->sgs;
@@ -1343,7 +1344,10 @@ static void nvme_update_disk_info(struct gendisk *disk,
 	blk_mq_freeze_queue(disk->queue);
 	blk_integrity_unregister(disk);
 
-	blk_queue_logical_block_size(disk->queue, 1 << ns->lba_shift);
+	bs = 1 << ns->lba_shift;
+	blk_queue_logical_block_size(disk->queue, bs);
+	blk_queue_physical_block_size(ns->queue, bs);
+    	blk_limits_io_min(&ns->queue->limits, bs);
 	if (ns->ms && !ns->ext &&
 	    (ns->ctrl->ops->flags & NVME_F_METADATA_SUPPORTED))
 		nvme_init_integrity(disk, ns->ms, ns->pi_type);
-- 
2.14.2.746.g8fb8a94

[PATCH] NVMe: Format fix when going from 4k sector size to 512 bytes

[Keith Busch]

On Thu, Dec 14, 2017@02:49:36PM -0600, Jeff Lien wrote:
> If you format a device with a 4k sector size back to 512 bytes,
> the queue limit values for physical block size and IO sizes were
> not getting updated; only the logical block size was being
> updated.  This patch adds code to update the physical block
> and IO sizes.

That's true, though I always considered that to be a happy accident. As
far as I know, most NVMe SSDs advertising a 512 byte logical block are
only emulating that size, and are natively 4k or larger.

[PATCH] NVMe: Format fix when going from 4k sector size to 512 bytes

[Martin K. Petersen]

Jeff,

> +	blk_queue_logical_block_size(disk->queue, bs);
> +	blk_queue_physical_block_size(ns->queue, bs);

A bit messy that you mix ns->queue and disk->queue.

> +    	blk_limits_io_min(&ns->queue->limits, bs);

blk_queue_io_min(foo->queue, bs);

Otherwise OK.

Reviewed-by: Martin K. Petersen <martin.petersen at oracle.com>

-- 
Martin K. Petersen	Oracle Linux Engineering

[PATCH] NVMe: Format fix when going from 4k sector size to 512 bytes

[Christoph Hellwig]

On Thu, Dec 14, 2017@10:52:11PM -0500, Martin K. Petersen wrote:
> 
> Jeff,
> 
> > +	blk_queue_logical_block_size(disk->queue, bs);
> > +	blk_queue_physical_block_size(ns->queue, bs);
> 
> A bit messy that you mix ns->queue and disk->queue.

It's not just ugly, but actually broken.  We must use disk->queue
both times to correctly handle multipathing.