Re: [PATCH] block: check disk flag before setting scan bit

Re: [PATCH] block: check disk flag before setting scan bit

[Jens Axboe]

On 1/16/23 1:38?AM, wangjie wrote:
> No need to scan partitions for disk who has set flag GENHD_FL_NO_PART in
> driver code. In disk_scan_partitions function, the same checking is
> existing, so we believe this change is reasonable.
> 
> In our case, some virtual block devices are not managed by GPT, then scan
> partition operation is not a must. So we set GENHD_FL_NO_PART flag in
> driver intended to avoid partitions being dropped/added.
> But GD_NEED_PART_SCAN bit was still set by bdev_check_media_change, which
> causing problems here.
> 
> Signed-off-by: wangjie

Signed-off-by is in the wrong format, and the whole email is badly
mangled...

> ????????????????????????????????????????????????????
> ????????????????????????????????????????????????????
> ???????????????????????????????

This didn't quote well, but the original is also useless. You do realize
you send this email to a public list? Please get rid of it.

-- 
Jens Axboe

[PATCH] block: check disk flag before setting scan bit

[Jie Wang]

No need to scan partitions for disk who has set flag GENHD_FL_NO_PART in
driver code. In disk_scan_partitions function, the same checking is
existing, so we believe this change is reasonable.

In our case, some virtual block devices are not managed by GPT, then scan
partition operation is not a must. So we set GENHD_FL_NO_PART flag in
driver intended to avoid partitions being dropped/added.
But GD_NEED_PART_SCAN bit was still set by bdev_check_media_change, which
causing problems here.

Signed-off-by: Jie Wang <wangjie2011cs@163.com>
---
 block/disk-events.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/block/disk-events.c b/block/disk-events.c
index aee25a7e1ab7..68d911135bc7 100644
--- a/block/disk-events.c
+++ b/block/disk-events.c
@@ -284,7 +284,8 @@ bool bdev_check_media_change(struct block_device *bdev)
 	if (__invalidate_device(bdev, true))
 		pr_warn("VFS: busy inodes on changed media %s\n",
 			bdev->bd_disk->disk_name);
-	set_bit(GD_NEED_PART_SCAN, &bdev->bd_disk->state);
+	if (!(bdev->bd_disk->flags & GENHD_FL_NO_PART))
+		set_bit(GD_NEED_PART_SCAN, &bdev->bd_disk->state);
 	return true;
 }
 EXPORT_SYMBOL(bdev_check_media_change);
@@ -310,7 +311,8 @@ bool disk_force_media_change(struct gendisk *disk, unsigned int events)
 	if (__invalidate_device(disk->part0, true))
 		pr_warn("VFS: busy inodes on changed media %s\n",
 			disk->disk_name);
-	set_bit(GD_NEED_PART_SCAN, &disk->state);
+	if (!(bdev->bd_disk->flags & GENHD_FL_NO_PART))
+		set_bit(GD_NEED_PART_SCAN, &disk->state);
 	return true;
 }
 EXPORT_SYMBOL_GPL(disk_force_media_change);
-- 
2.17.1

Re: [PATCH] block: check disk flag before setting scan bit

[Christoph Hellwig]

On Tue, Jan 17, 2023 at 03:53:29PM +0800, Jie Wang wrote:
> No need to scan partitions for disk who has set flag GENHD_FL_NO_PART in
> driver code. In disk_scan_partitions function, the same checking is
> existing, so we believe this change is reasonable.
> 
> In our case, some virtual block devices are not managed by GPT, then scan
> partition operation is not a must. So we set GENHD_FL_NO_PART flag in
> driver intended to avoid partitions being dropped/added.

What driver?

Re: [PATCH] block: check disk flag before setting scan bit

[Christoph Hellwig]

On Tue, Jan 17, 2023 at 04:57:33PM +0800, wangjie2011cs wrote:
> Nvidia tegra_virt_storage driver, which talks with hypervisor.

Merge it upstream first and we can talk.  Until then please don't waste
our time.