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Stefano, could you review the revised patch and share your comments? Thanks.
>>> Chunyan Liu <cyliu@xxxxxxxx> 10/28/2011 9:27 PM >>>
Start qemu-nbd to mount non-raw qdisk in dom0 so that xl can create PV guest with qcow/qcow2 disk image and using pygrub.
v2: use fork and exec instead of system(3)
Signed-off-by: Chunyan Liu <cyliu@xxxxxxxx>
diff -r b4cf57bbc3fb tools/libxl/libxl.c
--- a/tools/libxl/libxl.cThu Oct 20 15:24:46 2011 +0800
+++ b/tools/libxl/libxl.cFri Oct 28 20:50:36 2011 +0800
@@ -1077,6 +1077,58 @@ out_free:
libxl__free_all(&gc);
return rc;
}
+static int fork_exec(char *arg0, char **args)
+{
+ pid_t pid;
+ int status;
+
+ pid = fork();
+ if (pid < 0)
+ return -1;
+ else if (pid == 0){
+ execvp(arg0, args);
+ exit(127);
+ }
+ sleep(1);
+ while (waitpid(pid, &status, 0) < 0) {
+ if (errno != EINTR) {
+ status = -1;
+ break;
+ }
+ }
+
+ return status;
+}
+
+static char * nbd_mount_disk(libxl__gc *gc, libxl_device_disk *disk)
+{
+ int i;
+ int nbds_max = 16;
+ char *nbd_dev = NULL;
+ char *args[] = {"qemu-nbd","-c",NULL,NULL,NULL};
+ char *ret = NULL;
+
+ for (i = 0; i < nbds_max; i++) {
+ nbd_dev = libxl__sprintf(gc, "/dev/nbd%d", i);
+ args[2] = libxl__sprintf(gc, "%s", nbd_dev);
+ args[3] = libxl__sprintf(gc, "%s", disk->pdev_path);
+ if (fork_exec(args[0], args) == 0) {
+ ret = strdup(nbd_dev);
+ break;
+ }
+ }
+
+ return ret;
+}
+
+static int nbd_unmount_disk(libxl__gc *gc, char *diskpath) {
+ char *args[] = {"qemu-nbd","-d",NULL,NULL};
+ args[2] = libxl__sprintf(gc, "%s", diskpath);
+ if (fork_exec(args[0], args))
+ return 0;
+ else
+ return ERROR_FAIL;
+}
char * libxl_device_disk_local_attach(libxl_ctx *ctx, libxl_device_disk *disk)
{
@@ -1084,6 +1136,7 @@ char * libxl_device_disk_local_attach(li
char *dev = NULL;
char *ret = NULL;
int rc;
+ char *mdev = NULL;
rc = libxl__device_disk_set_backend(&gc, disk);
if (rc) goto out;
@@ -1118,8 +1171,12 @@ char * libxl_device_disk_local_attach(li
break;
case LIBXL_DISK_BACKEND_QDISK:
if (disk->format != LIBXL_DISK_FORMAT_RAW) {
- LIBXL__LOG(ctx, LIBXL__LOG_ERROR, "cannot locally"
- " attach a qdisk image if the format is not raw");
+ LIBXL__LOG(ctx, LIBXL__LOG_DEBUG, "attaching a non-raw qdisk image to domain 0\n");
+ mdev = nbd_mount_disk(&gc, disk);
+ if (mdev)
+ dev = mdev;
+ else
+ LIBXL__LOG(ctx, LIBXL__LOG_ERROR, "fail to mount image with qemu-nbd");
break;
}
LIBXL__LOG(ctx, LIBXL__LOG_DEBUG, "locally attaching qdisk %s\n",
@@ -1135,11 +1192,13 @@ char * libxl_device_disk_local_attach(li
out:
if (dev != NULL)
ret = strdup(dev);
+ if (mdev)
+ free(mdev);
libxl__free_all(&gc);
return ret;
}
-int libxl_device_disk_local_detach(libxl_ctx *ctx, libxl_device_disk *disk)
+int libxl_device_disk_local_detach(libxl_ctx *ctx, libxl_device_disk *disk, char *diskpath)
{
/* Nothing to do for PHYSTYPE_PHY. */
@@ -1147,7 +1206,22 @@ int libxl_device_disk_local_detach(libxl
* For other device types assume that the blktap2 process is
* needed by the soon to be started domain and do nothing.
*/
+ libxl__gc gc = LIBXL_INIT_GC(ctx);
+ int ret;
+ switch (disk->backend) {
+ case LIBXL_DISK_BACKEND_QDISK:
+ if (disk->format != LIBXL_DISK_FORMAT_RAW) {
+ LIBXL__LOG(ctx, LIBXL__LOG_DEBUG, "Locally detach a non-raw "
+ "qdisk image");
+ ret = nbd_unmount_disk(&gc, diskpath);
+ return ret;
+ }
+ default:
+ break;
+ }
+
+ libxl__free_all(&gc);
return 0;
}
diff -r b4cf57bbc3fb tools/libxl/libxl.h
--- a/tools/libxl/libxl.hThu Oct 20 15:24:46 2011 +0800
+++ b/tools/libxl/libxl.hFri Oct 28 20:50:36 2011 +0800
@@ -390,7 +390,7 @@ int libxl_cdrom_insert(libxl_ctx *ctx, u
* Make a disk available in this domain. Returns path to a device.
*/
char * libxl_device_disk_local_attach(libxl_ctx *ctx, libxl_device_disk *disk);
-int libxl_device_disk_local_detach(libxl_ctx *ctx, libxl_device_disk *disk);
+int libxl_device_disk_local_detach(libxl_ctx *ctx, libxl_device_disk *disk, char *diskpath);
int libxl_device_nic_init(libxl_device_nic *nic, int dev_num);
int libxl_device_nic_add(libxl_ctx *ctx, uint32_t domid, libxl_device_nic *nic);
diff -r b4cf57bbc3fb tools/libxl/libxl_bootloader.c
--- a/tools/libxl/libxl_bootloader.cThu Oct 20 15:24:46 2011 +0800
+++ b/tools/libxl/libxl_bootloader.cFri Oct 28 20:50:36 2011 +0800
@@ -424,7 +424,7 @@ int libxl_run_bootloader(libxl_ctx *ctx,
rc = 0;
out_close:
if (diskpath) {
- libxl_device_disk_local_detach(ctx, disk);
+ libxl_device_disk_local_detach(ctx, disk, diskpath);
free(diskpath);
}
if (fifo_fd > -1)
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