2009-07-21 05:56:30

by Nikanth Karthikesan

Subject: [RESEND][PATCH] Send uevents for disk write_protect changes

Hi

This patch is needed for the dm-multipath, so that the daemon can capture the
event and reload the dm table when the read-only setting of the disk changes.
Can this be merged?

Thanks
Nikanth

From: Hannes Reinecke <[email protected]>
Subject: Send uevents for write_protect changes

Whenever a block device changes it's read-only attribute
notify the userspace about it.

Signed-off-by: Hannes Reinecke <[email protected]>
Signed-off-by: Nikanth Karthikesan <[email protected]>

---

diff --git a/block/genhd.c b/block/genhd.c
index f4c64c2..b89328e 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -1215,6 +1215,16 @@ void put_disk(struct gendisk *disk)

EXPORT_SYMBOL(put_disk);

+static void set_disk_ro_uevent(struct gendisk *gd, int ro)
+{
+ char event[] = "DISK_RO=1";
+ char *envp[] = { event, NULL };
+
+ if (!ro)
+ event[8] = '0';
+ kobject_uevent_env(&disk_to_dev(gd)->kobj, KOBJ_CHANGE, envp);
+}
+
void set_device_ro(struct block_device *bdev, int flag)
{
bdev->bd_part->policy = flag;
@@ -1227,8 +1237,12 @@ void set_disk_ro(struct gendisk *disk, int flag)
struct disk_part_iter piter;
struct hd_struct *part;

- disk_part_iter_init(&piter, disk,
- DISK_PITER_INCL_EMPTY | DISK_PITER_INCL_PART0);
+ if (disk->part0.policy != flag) {
+ set_disk_ro_uevent(disk, flag);
+ disk->part0.policy = flag;
+ }
+
+ disk_part_iter_init(&piter, disk, DISK_PITER_INCL_EMPTY);
while ((part = disk_part_iter_next(&piter)))
part->policy = flag;
disk_part_iter_exit(&piter);

2009-07-21 13:39:53

by Tejun Heo

Subject: Re: [RESEND][PATCH] Send uevents for disk write_protect changes

Nikanth Karthikesan wrote:
> Hi
>
> This patch is needed for the dm-multipath, so that the daemon can capture the
> event and reload the dm table when the read-only setting of the disk changes.
> Can this be merged?

This is for the next merge window, right?

Thanks.

--
tejun

2009-07-28 07:12:59

by Jens Axboe

Subject: Re: [RESEND][PATCH] Send uevents for disk write_protect changes

On Tue, Jul 21 2009, Nikanth Karthikesan wrote:
> Hi
>
> This patch is needed for the dm-multipath, so that the daemon can capture the
> event and reload the dm table when the read-only setting of the disk changes.
> Can this be merged?

Looks fine to me, merged for 2.6.32.

>
> Thanks
> Nikanth
>
> From: Hannes Reinecke <[email protected]>
> Subject: Send uevents for write_protect changes
>
> Whenever a block device changes it's read-only attribute
> notify the userspace about it.
>
> Signed-off-by: Hannes Reinecke <[email protected]>
> Signed-off-by: Nikanth Karthikesan <[email protected]>
>
> ---
>
> diff --git a/block/genhd.c b/block/genhd.c
> index f4c64c2..b89328e 100644
> --- a/block/genhd.c
> +++ b/block/genhd.c
> @@ -1215,6 +1215,16 @@ void put_disk(struct gendisk *disk)
>
> EXPORT_SYMBOL(put_disk);
>
> +static void set_disk_ro_uevent(struct gendisk *gd, int ro)
> +{
> + char event[] = "DISK_RO=1";
> + char *envp[] = { event, NULL };
> +
> + if (!ro)
> + event[8] = '0';
> + kobject_uevent_env(&disk_to_dev(gd)->kobj, KOBJ_CHANGE, envp);
> +}
> +
> void set_device_ro(struct block_device *bdev, int flag)
> {
> bdev->bd_part->policy = flag;
> @@ -1227,8 +1237,12 @@ void set_disk_ro(struct gendisk *disk, int flag)
> struct disk_part_iter piter;
> struct hd_struct *part;
>
> - disk_part_iter_init(&piter, disk,
> - DISK_PITER_INCL_EMPTY | DISK_PITER_INCL_PART0);
> + if (disk->part0.policy != flag) {
> + set_disk_ro_uevent(disk, flag);
> + disk->part0.policy = flag;
> + }
> +
> + disk_part_iter_init(&piter, disk, DISK_PITER_INCL_EMPTY);
> while ((part = disk_part_iter_next(&piter)))
> part->policy = flag;
> disk_part_iter_exit(&piter);
>
>

--
Jens Axboe