storage: Adjust qemu-img switches check

Since we support QEMU 0.12 and later, checking for support of specific flags
added prior to that isn't necessary.

Thus start with the base of having the "-o options" available for the
qemu-img create option and then determine whether we have the compat
option for qcow2 files (which would be necessary up through qemu 2.0
where the default changes to compat 0.11).

Adjust test to no long check for NONE and FLAG options as well was removing
results of tests that would use that option.
Signed-off-by: NJohn Ferlan <jferlan@redhat.com>

src/storage/storage_backend.c

@@ -869,10 +869,15 @@ virStoragePloopResize(virStorageVolDefPtr vol,
     return ret;
 }
 
+/* Flag values shared w/ storagevolxml2argvtest.c.
+ *
+ * QEMU_IMG_BACKING_FORMAT_OPTIONS (added in qemu 0.11)
+ * QEMU_IMG_BACKING_FORMAT_OPTIONS_COMPAT
+ *    was made necessary due to 2.0 change to change the default
+ *    qcow2 file format from 0.10 to 1.1.
+ */
 enum {
-    QEMU_IMG_BACKING_FORMAT_NONE = 0,
-    QEMU_IMG_BACKING_FORMAT_FLAG,
-    QEMU_IMG_BACKING_FORMAT_OPTIONS,
+    QEMU_IMG_BACKING_FORMAT_OPTIONS = 0,
     QEMU_IMG_BACKING_FORMAT_OPTIONS_COMPAT,
 };
 
@@ -904,46 +909,18 @@ virStorageBackendQemuImgSupportsCompat(const char *qemuimg)
 static int
 virStorageBackendQEMUImgBackingFormat(const char *qemuimg)
 {
-    char *help = NULL;
-    char *start;
-    char *end;
-    char *tmp;
-    int ret = -1;
-    int exitstatus;
-    virCommandPtr cmd = virCommandNewArgList(qemuimg, "-h", NULL);
-
-    virCommandAddEnvString(cmd, "LC_ALL=C");
-    virCommandSetOutputBuffer(cmd, &help);
-    virCommandClearCaps(cmd);
-
-    /* qemuimg doesn't return zero exit status on -h,
-     * therefore we need to provide pointer for storing
-     * exit status, although we don't parse it any later */
-    if (virCommandRun(cmd, &exitstatus) < 0)
-        goto cleanup;
-
-    if ((start = strstr(help, " create ")) == NULL ||
-        (end = strstr(start, "\n")) == NULL) {
-        virReportError(VIR_ERR_INTERNAL_ERROR,
-                       _("unable to parse qemu-img output '%s'"),
-                       help);
-        goto cleanup;
-    }
-    if (((tmp = strstr(start, "-F fmt")) && tmp < end) ||
-        ((tmp = strstr(start, "-F backing_fmt")) && tmp < end)) {
-        ret = QEMU_IMG_BACKING_FORMAT_FLAG;
-    } else if ((tmp = strstr(start, "[-o options]")) && tmp < end) {
-        if (virStorageBackendQemuImgSupportsCompat(qemuimg))
-            ret = QEMU_IMG_BACKING_FORMAT_OPTIONS_COMPAT;
-        else
-            ret = QEMU_IMG_BACKING_FORMAT_OPTIONS;
-    } else {
-        ret = QEMU_IMG_BACKING_FORMAT_NONE;
-    }
+    /* As of QEMU 0.11 the [-o options] support was added via qemu
+     * commit id '9ea2ea71', so we start with that base and figure
+     * out what else we have */
+    int ret = QEMU_IMG_BACKING_FORMAT_OPTIONS;
+
+    /* QEMU 2.0 changed to using a format that only QEMU 1.1 and newer
+     * understands. Since we still support QEMU 0.12 and newer, we need
+     * to be able to handle the previous format as can be set via a
+     * compat=0.10 option. */
+    if (virStorageBackendQemuImgSupportsCompat(qemuimg))
+        ret = QEMU_IMG_BACKING_FORMAT_OPTIONS_COMPAT;
 
- cleanup:
-    virCommandFree(cmd);
-    VIR_FREE(help);
     return ret;
 }
 
@@ -1218,29 +1195,17 @@ virStorageBackendCreateQemuImgCmdFromVol(virConnectPtr conn,
     if (info.backingPath)
         virCommandAddArgList(cmd, "-b", info.backingPath, NULL);
 
-    if (imgformat >= QEMU_IMG_BACKING_FORMAT_OPTIONS) {
-        if (info.format == VIR_STORAGE_FILE_QCOW2 && !info.compat &&
-            imgformat == QEMU_IMG_BACKING_FORMAT_OPTIONS_COMPAT)
-            info.compat = "0.10";
+    if (info.format == VIR_STORAGE_FILE_QCOW2 && !info.compat &&
+        imgformat >= QEMU_IMG_BACKING_FORMAT_OPTIONS_COMPAT)
+        info.compat = "0.10";
 
-        if (virStorageBackendCreateQemuImgOpts(&opts, info) < 0) {
-            virCommandFree(cmd);
-            return NULL;
-        }
-        if (opts)
-            virCommandAddArgList(cmd, "-o", opts, NULL);
-        VIR_FREE(opts);
-    } else {
-        if (info.backingPath) {
-            if (imgformat == QEMU_IMG_BACKING_FORMAT_FLAG)
-                virCommandAddArgList(cmd, "-F", backingType, NULL);
-            else
-                VIR_DEBUG("Unable to set backing store format for %s with %s",
-                          info.path, create_tool);
-        }
-        if (info.encryption)
-            virCommandAddArg(cmd, "-e");
+    if (virStorageBackendCreateQemuImgOpts(&opts, info) < 0) {
+        virCommandFree(cmd);
+        return NULL;
     }
+    if (opts)
+        virCommandAddArgList(cmd, "-o", opts, NULL);
+    VIR_FREE(opts);
 
     if (info.inputPath)
         virCommandAddArg(cmd, info.inputPath);

tests/storagevolxml2argvdata/qcow2-flag.argv

-qemu-img create -f qcow2 -b /dev/null -F raw \
--e /var/lib/libvirt/images/OtherDemo.img 5242880K

tests/storagevolxml2argvdata/qcow2-nobacking-convert-flag.argv

-qemu-img convert -f raw -O qcow2 -e /var/lib/libvirt/images/sparse.img \
-/var/lib/libvirt/images/OtherDemo.img

tests/storagevolxml2argvdata/qcow2-nobacking-convert-none.argv

-qemu-img convert -f raw -O qcow2 -e /var/lib/libvirt/images/sparse.img \
-/var/lib/libvirt/images/OtherDemo.img

tests/storagevolxml2argvdata/qcow2-nobacking-flag.argv

-qemu-img create -f qcow2 -e /var/lib/libvirt/images/OtherDemo.img 5242880K

tests/storagevolxml2argvdata/qcow2-nobacking-none.argv

-qemu-img create -f qcow2 -e /var/lib/libvirt/images/OtherDemo.img 5242880K

tests/storagevolxml2argvdata/qcow2-none.argv

-qemu-img create -f qcow2 -b /dev/null -e /var/lib/libvirt/images/OtherDemo.img 5242880K

tests/storagevolxml2argvtest.c

@@ -168,9 +168,7 @@ testCompareXMLToArgvHelper(const void *data)
 }
 
 enum {
-    FMT_NONE = 0,
-    FMT_FLAG,
-    FMT_OPTIONS,
+    FMT_OPTIONS = 0,
     FMT_COMPAT,
 };
 
@@ -217,24 +215,6 @@ mymain(void)
     DO_TEST_FAIL("pool-dir", "vol-qcow2",
                  "pool-dir", "vol-file",
                  "qcow2-convert-prealloc", flags, FMT_OPTIONS);
-    DO_TEST("pool-dir", "vol-qcow2",
-            NULL, NULL,
-            "qcow2-flag", 0, FMT_FLAG);
-    DO_TEST("pool-dir", "vol-qcow2-nobacking",
-            NULL, NULL,
-            "qcow2-nobacking-flag", 0, FMT_FLAG);
-    DO_TEST("pool-dir", "vol-qcow2-nobacking",
-            "pool-dir", "vol-file",
-            "qcow2-nobacking-convert-flag", 0, FMT_FLAG);
-    DO_TEST("pool-dir", "vol-qcow2",
-            NULL, NULL,
-            "qcow2-none", 0, FMT_NONE);
-    DO_TEST("pool-dir", "vol-qcow2-nobacking",
-            NULL, NULL,
-            "qcow2-nobacking-none", 0, FMT_NONE);
-    DO_TEST("pool-dir", "vol-qcow2-nobacking",
-            "pool-dir", "vol-file",
-            "qcow2-nobacking-convert-none", 0, FMT_NONE);
     DO_TEST("pool-dir", "vol-qcow2-lazy",
             NULL, NULL,
             "qcow2-lazy", 0, FMT_OPTIONS);