[RFC Patch v2 41/45] support blktap remus in xl

[Wen Congyang <wency@cn.fujitsu.com>]

With this patch, we can use blktap remus like this:
disk = [ 'format=remus,devtype=disk,access=w,vdev=hda,backendtype=tap,target=192.168.3.1:9000|aio:filename' ]
---
 tools/libxl/libxl_blktap2.c   | 33 +++++++++++++++++++++++++++++++++
 tools/libxl/libxl_device.c    |  4 +++-
 tools/libxl/libxl_dm.c        |  8 ++++++++
 tools/libxl/libxl_internal.h  |  4 ++++
 tools/libxl/libxl_noblktap2.c |  6 ++++++
 tools/libxl/libxl_types.idl   |  1 +
 tools/libxl/libxlu_disk_l.l   |  1 +
 7 files changed, 56 insertions(+), 1 deletion(-)

diff --git a/tools/libxl/libxl_blktap2.c b/tools/libxl/libxl_blktap2.c
index 2053403..7bbdfc8 100644
--- a/tools/libxl/libxl_blktap2.c
+++ b/tools/libxl/libxl_blktap2.c
@@ -32,6 +32,10 @@ char *libxl__blktap_devpath(libxl__gc *gc,
     tap_list_t tap;
     int err;
 
+    if (format == LIBXL_DISK_FORMAT_REMUS)
+        if (libxl__blktap_get_real_format(gc, disk, format) < 0)
+            return NULL;
+
     type = libxl__device_disk_string_of_format(format);
     err = tap_ctl_find(type, disk, &tap);
     if (err == 0) {
@@ -84,6 +88,35 @@ int libxl__device_destroy_tapdisk(libxl__gc *gc, const char *params)
     return 0;
 }
 
+libxl_disk_format libxl__blktap_get_real_format(libxl__gc *gc,
+                                                const char *disk,
+                                                libxl_disk_format format)
+{
+    const char *type;
+
+    if (format != LIBXL_DISK_FORMAT_REMUS)
+        return format;
+
+    /* The format of disk: ip:port|xxx:file */
+    type = strchr(disk, '|');
+    if (!type) {
+        LOG(ERROR, "Unable to parse params %s", disk);
+        return ERROR_FAIL;
+    }
+
+    type++;
+
+    /* libxl only supports aio/vhd(see disk_try_backend()) */
+    if (!strncmp(type, "aio:", 4))
+        return LIBXL_DISK_FORMAT_RAW;
+    else if (!strncmp(type, "vhd:", 4))
+        return LIBXL_DISK_FORMAT_VHD;
+
+    LOG(ERROR, "Unsupported format: %s", type);
+
+    return ERROR_FAIL;
+}
+
 /*
  * Local variables:
  * mode: C
diff --git a/tools/libxl/libxl_device.c b/tools/libxl/libxl_device.c
index 89dc824..a460d33 100644
--- a/tools/libxl/libxl_device.c
+++ b/tools/libxl/libxl_device.c
@@ -211,7 +211,8 @@ static int disk_try_backend(disk_try_backend_args *a,
             return 0;
         }
         if (!(a->disk->format == LIBXL_DISK_FORMAT_RAW ||
-              a->disk->format == LIBXL_DISK_FORMAT_VHD)) {
+              a->disk->format == LIBXL_DISK_FORMAT_VHD ||
+              a->disk->format == LIBXL_DISK_FORMAT_REMUS)) {
             goto bad_format;
         }
         return backend;
@@ -295,6 +296,7 @@ char *libxl__device_disk_string_of_format(libxl_disk_format format)
         case LIBXL_DISK_FORMAT_VHD: return "vhd";
         case LIBXL_DISK_FORMAT_RAW:
         case LIBXL_DISK_FORMAT_EMPTY: return "aio";
+        case LIBXL_DISK_FORMAT_REMUS: return "remus";
         default: return NULL;
     }
 }
diff --git a/tools/libxl/libxl_dm.c b/tools/libxl/libxl_dm.c
index d86ce15..a7ce6d2 100644
--- a/tools/libxl/libxl_dm.c
+++ b/tools/libxl/libxl_dm.c
@@ -681,6 +681,7 @@ static char ** libxl__build_device_model_args_new(libxl__gc *gc,
             const char *format = qemu_disk_format_string(disks[i].format);
             char *drive;
             const char *pdev_path;
+            libxl_disk_format real_format;
 
             if (dev_number == -1) {
                 LIBXL__LOG(ctx, LIBXL__LOG_WARNING, "unable to determine"
@@ -688,6 +689,13 @@ static char ** libxl__build_device_model_args_new(libxl__gc *gc,
                 continue;
             }
 
+            if (disks[i].format == LIBXL_DISK_FORMAT_REMUS) {
+                real_format = libxl__blktap_get_real_format(gc,
+                                                            disks[i].pdev_path,
+                                                            disks[i].format);
+                format = qemu_disk_format_string(real_format);
+            }
+
             if (disks[i].is_cdrom) {
                 if (disks[i].format == LIBXL_DISK_FORMAT_EMPTY)
                     drive = libxl__sprintf
diff --git a/tools/libxl/libxl_internal.h b/tools/libxl/libxl_internal.h
index 6fc26c9..4478c70 100644
--- a/tools/libxl/libxl_internal.h
+++ b/tools/libxl/libxl_internal.h
@@ -1535,6 +1535,10 @@ _hidden char *libxl__blktap_devpath(libxl__gc *gc,
  */
 _hidden int libxl__device_destroy_tapdisk(libxl__gc *gc, const char *params);
 
+_hidden libxl_disk_format libxl__blktap_get_real_format(libxl__gc *gc,
+                                                        const char *disk,
+                                                        libxl_disk_format format);
+
 _hidden int libxl__device_from_disk(libxl__gc *gc, uint32_t domid,
                                    libxl_device_disk *disk,
                                    libxl__device *device);
diff --git a/tools/libxl/libxl_noblktap2.c b/tools/libxl/libxl_noblktap2.c
index 5a86ed1..38696ec 100644
--- a/tools/libxl/libxl_noblktap2.c
+++ b/tools/libxl/libxl_noblktap2.c
@@ -33,6 +33,12 @@ int libxl__device_destroy_tapdisk(libxl__gc *gc, const char *params)
     return 0;
 }
 
+libxl_disk_format libxl__blktap_get_real_format(const char *disk,
+                                                libxl_disk_format format)
+{
+    return format;
+}
+
 /*
  * Local variables:
  * mode: C
diff --git a/tools/libxl/libxl_types.idl b/tools/libxl/libxl_types.idl
index 599f137..6bcb8b6 100644
--- a/tools/libxl/libxl_types.idl
+++ b/tools/libxl/libxl_types.idl
@@ -87,6 +87,7 @@ libxl_disk_format = Enumeration("disk_format", [
     (3, "VHD"),
     (4, "RAW"),
     (5, "EMPTY"),
+    (6, "REMUS"),
     ])
 
 libxl_disk_backend = Enumeration("disk_backend", [
diff --git a/tools/libxl/libxlu_disk_l.l b/tools/libxl/libxlu_disk_l.l
index 1a5deb5..d9ff8a1 100644
--- a/tools/libxl/libxlu_disk_l.l
+++ b/tools/libxl/libxlu_disk_l.l
@@ -102,6 +102,7 @@ static void setformat(DiskParseContext *dpc, const char *str) {
     else if (!strcmp(str,"qcow2"))  DSET(dpc,format,FORMAT,str,QCOW2);
     else if (!strcmp(str,"vhd"))    DSET(dpc,format,FORMAT,str,VHD);
     else if (!strcmp(str,"empty"))  DSET(dpc,format,FORMAT,str,EMPTY);
+    else if (!strcmp(str,"remus"))  DSET(dpc,format,FORMAT,str,REMUS);
     else xlu__disk_err(dpc,str,"unknown value for format");
 }
 
-- 
1.9.3