blkfront: add uevent for size change

When a blkfront device is resized from dom0, emit a KOBJ_CHANGE uevent to
notify the guest about the change. This allows for custom udev rules, such
as automatically resizing a filesystem, when an event occurs.

With this patch you get these udev

KERNEL[577.206230] change   /devices/vbd-51728/block/xvdb (block)
UDEV  [577.226218] change   /devices/vbd-51728/block/xvdb (block)

Signed-off-by: Marc Olson <marcolso@amazon.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
OraBug: 26662731

(cherry picked from commit 89515d0255c918e08aa4085956c79bf17615fda5)
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Reviewed-by: Joao Martins <joao.m.martins@oracle.com>

diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index 3e4576854364d3a379d1a82e818487e0122aad2c..d824ef13c82d0990ec845bfbaf6e6b80de8bb251 100644 (file)
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -2594,6 +2594,7 @@ static void blkfront_connect(struct blkfront_info *info)
        unsigned long sector_size;
        unsigned int physical_sector_size;
        unsigned int binfo;
+       char *envp[] = { "RESIZE=1", NULL };
        int err, i;
 
        switch (info->connected) {
@@ -2610,6 +2611,8 @@ static void blkfront_connect(struct blkfront_info *info)
                       sectors);
                set_capacity(info->gd, sectors);
                revalidate_disk(info->gd);
+               kobject_uevent_env(&disk_to_dev(info->gd)->kobj,
+                                  KOBJ_CHANGE, envp);
 
                return;
        case BLKIF_STATE_SUSPENDED: