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

Nikanth Karthikesan
2009-07-21T05:56:30Z

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 <hare@suse.de>
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 <hare@suse.de>
Signed-off-by: Nikanth Karthikesan <knikanth@suse.de>

---

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);