Add helper which will map values of disk cache mode to the flags which
are accepted by various parts of the qemu block layer.
Signed-off-by: Peter Krempa <pkrempa@xxxxxxxxxx>
---
src/qemu/qemu_domain.c | 75 ++++++++++++++++++++++++++++++++++++++++++++++++++
src/qemu/qemu_domain.h | 6 ++++
2 files changed, 81 insertions(+)
diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c
index 9d1c33b54a..20333c9568 100644
--- a/src/qemu/qemu_domain.c
+++ b/src/qemu/qemu_domain.c
@@ -11920,6 +11920,81 @@ qemuDomainPrepareDiskSource(virDomainDiskDefPtr disk,
}
+/**
+ * qemuDomainDiskCachemodeFlags:
+ *
+ * Converts disk cachemode to the cache mode options for qemu. Returns -1 for
+ * invalid @cachemode values and fills the flags and returns 0 on success.
+ * Flags may be NULL.
+ */
+int
+qemuDomainDiskCachemodeFlags(int cachemode,
+ bool *writeback,
+ bool *direct,
+ bool *noflush)
+{
+ bool dummy;
+
+ if (!writeback)
+ writeback = &dummy;
+
+ if (!direct)
+ direct = &dummy;
+
+ if (!noflush)
+ noflush = &dummy;
+
+ /* Mapping of cache modes to the attributes according to qemu-options.hx
+ * │ cache.writeback cache.direct cache.no-flush
+ * ─────────────┼─────────────────────────────────────────────────
+ * writeback │ true false false
+ * none │ true true false
+ * writethrough │ false false false
+ * directsync │ false true false
+ * unsafe │ true false true
+ */
+ switch ((virDomainDiskCache) cachemode) {
+ case VIR_DOMAIN_DISK_CACHE_DISABLE: /* 'none' */
+ *writeback = true;
+ *direct = true;
+ *noflush = false;
+ break;
+
+ case VIR_DOMAIN_DISK_CACHE_WRITETHRU:
+ *writeback = false;
+ *direct = false;
+ *noflush = false;
+ break;
+
+ case VIR_DOMAIN_DISK_CACHE_WRITEBACK:
+ *writeback = true;
+ *direct = false;
+ *noflush = false;
+ break;
+
+ case VIR_DOMAIN_DISK_CACHE_DIRECTSYNC:
+ *writeback = false;
+ *direct = true;
+ *noflush = false;
+ break;
+
+ case VIR_DOMAIN_DISK_CACHE_UNSAFE:
+ *writeback = true;
+ *direct = false;
+ *noflush = true;
+ break;
+
+ case VIR_DOMAIN_DISK_CACHE_DEFAULT:
+ case VIR_DOMAIN_DISK_CACHE_LAST:
+ default:
+ virReportEnumRangeError(virDomainDiskCache, cachemode);
+ return -1;
+ }
+
+ return 0;
+}
+
+
void
qemuProcessEventFree(struct qemuProcessEvent *event)
{
diff --git a/src/qemu/qemu_domain.h b/src/qemu/qemu_domain.h
index 21e12f6594..bbc2e83760 100644
--- a/src/qemu/qemu_domain.h
+++ b/src/qemu/qemu_domain.h
@@ -1003,4 +1003,10 @@ qemuDomainPrepareDiskSource(virDomainDiskDefPtr disk,
qemuDomainObjPrivatePtr priv,
virQEMUDriverConfigPtr cfg);
+int
+qemuDomainDiskCachemodeFlags(int cachemode,
+ bool *writeback,
+ bool *direct,
+ bool *noflush);
+
#endif /* __QEMU_DOMAIN_H__ */
--
2.16.2
--
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