patch CA-15586-blkback-close-bdev

diff --git a/drivers/xen/blkback/common.h b/drivers/xen/blkback/common.h
index 2c978c3ab6fce81661d3167afd0e2ecf87b9a982..da9f8223744c3485dfe90a9c32a8054b6f0a0fc6 100644 (file)
--- a/drivers/xen/blkback/common.h
+++ b/drivers/xen/blkback/common.h
@@ -48,7 +48,11 @@
        pr_debug("(file=%s, line=%d) " _f,      \
                 __FILE__ , __LINE__ , ## _a )
 
-#define WPRINTK(fmt, args...) printk(KERN_WARNING "blk_tap: " fmt, ##args)
+#define WPRINTK(fmt, args...)                                  \
+do {                                                           \
+       if (printk_ratelimit())                                 \
+               printk(KERN_WARNING "blk_back: " fmt, ##args);  \
+} while(0)
 
 struct vbd {
        blkif_vdev_t   handle;      /* what the domain refers to this vbd as */

diff --git a/drivers/xen/blkback/xenbus.c b/drivers/xen/blkback/xenbus.c
index de1ef2b28f910fe33499d1657d73b0c4fb81e53f..0a31705ab0f50acaef1093b814e021d3c08c1274 100644 (file)
--- a/drivers/xen/blkback/xenbus.c
+++ b/drivers/xen/blkback/xenbus.c
@@ -298,7 +298,9 @@ static int blkback_remove(struct xenbus_device *dev)
 void blkback_close(blkif_t *blkif)
 {
        blkif_disconnect(blkif);
-       vbd_sync(&blkif->vbd);
+       vbd_free(&blkif->vbd);
+       blkif->be->major = 0;
+       blkif->be->minor = 0;
        blkif->remove_requested = 0;
 
        down(&blkback_dev_sem);
@@ -442,6 +444,71 @@ fail:
        return err;
 }
 
+static int blkback_open_bdev(struct backend_info *be)
+{
+       int err;
+       char *p;
+       long handle;
+       int cdrom = 0;
+       unsigned major;
+       unsigned minor;
+       char *device_type;
+       struct xenbus_device *dev = be->dev;
+
+       if (be->blkif->vbd.bdev) {
+               xenbus_dev_fatal(dev, -EINVAL, "attempting invalid vbd open");
+               return -EINVAL;
+       }
+
+       err = xenbus_scanf(XBT_NIL, dev->nodename, "physical-device", "%x:%x",
+                          &major, &minor);
+       if (err != 2) {
+               xenbus_dev_fatal(dev, err, "reading physical-device");
+               return err;
+       }
+
+       if ((be->major || be->minor) &&
+           ((be->major != major) || (be->minor != minor))) {
+               printk(KERN_WARNING
+                      "blkback: changing physical device (from %x:%x to "
+                      "%x:%x) not supported.\n", be->major, be->minor,
+                      major, minor);
+               xenbus_dev_fatal(dev, err, "invalid physical-device change");
+               return -EINVAL;
+       }
+
+       if (!be->mode) {
+               be->mode = xenbus_read(XBT_NIL, dev->nodename, "mode", NULL);
+               if (IS_ERR(be->mode)) {
+                       err = PTR_ERR(be->mode);
+                       be->mode = NULL;
+                       xenbus_dev_fatal(dev, err, "reading mode");
+                       return err;
+               }
+       }
+
+       device_type = xenbus_read(XBT_NIL, dev->otherend, "device-type", NULL);
+       if (!IS_ERR(device_type)) {
+               cdrom = strcmp(device_type, "cdrom") == 0;
+               kfree(device_type);
+       }
+
+       /* Front end dir is a number, which is used as the handle. */
+       p = strrchr(dev->otherend, '/') + 1;
+       handle = simple_strtoul(p, NULL, 0);
+
+       err = vbd_create(be->blkif, handle, major, minor,
+                        (NULL == strchr(be->mode, 'w')), cdrom);
+       if (err) {
+               xenbus_dev_fatal(dev, err, "creating vbd structure");
+               return err;
+       }
+
+       be->major = major;
+       be->minor = minor;
+
+       return 0;
+}
 
 /**
  * Callback received when the hotplug scripts have placed the physical-device
@@ -457,8 +524,6 @@ static void backend_changed(struct xenbus_watch *watch,
        struct backend_info *be
                = container_of(watch, struct backend_info, backend_watch);
        struct xenbus_device *dev = be->dev;
-       int cdrom = 0;
-       char *device_type;
 
        DPRINTK("");
 
@@ -484,6 +549,11 @@ static void backend_changed(struct xenbus_watch *watch,
                return;
        }
 
+       if (be->mode) {
+               kfree(be->mode);
+               be->mode = NULL;
+       }
+
        be->mode = xenbus_read(XBT_NIL, dev->nodename, "mode", NULL);
        if (IS_ERR(be->mode)) {
                err = PTR_ERR(be->mode);
@@ -492,28 +562,10 @@ static void backend_changed(struct xenbus_watch *watch,
                return;
        }
 
-       device_type = xenbus_read(XBT_NIL, dev->otherend, "device-type", NULL);
-       if (!IS_ERR(device_type)) {
-               cdrom = strcmp(device_type, "cdrom") == 0;
-               kfree(device_type);
-       }
-
        if (be->major == 0 && be->minor == 0) {
-               /* Front end dir is a number, which is used as the handle. */
-
-               char *p = strrchr(dev->otherend, '/') + 1;
-               long handle = simple_strtoul(p, NULL, 0);
-
-               be->major = major;
-               be->minor = minor;
-
-               err = vbd_create(be->blkif, handle, major, minor,
-                                (NULL == strchr(be->mode, 'w')), cdrom);
-               if (err) {
-                       be->major = be->minor = 0;
-                       xenbus_dev_fatal(dev, err, "creating vbd structure");
+               err = blkback_open_bdev(be);
+               if (err)
                        return;
-               }
 
                err = xenvbd_sysfs_addif(dev);
                if (err) {
@@ -558,10 +610,18 @@ static void frontend_changed(struct xenbus_device *dev,
                /* Ensure we connect even when two watches fire in 
                   close successsion and we miss the intermediate value 
                   of frontend_state. */
-               if (dev->state != XenbusStateConnected && dev->state != XenbusStateClosing) {
+               if (dev->state != XenbusStateConnected &&
+                   dev->state != XenbusStateClosing) {
                        err = connect_ring(be);
                        if (err)
                                break;
+
+                       if (!be->blkif->vbd.bdev) {
+                               err = blkback_open_bdev(be);
+                               if (err)
+                                       break;
+                       }
+
                        update_blkif_status(be->blkif);
                }