block: parse cache mode flags in a single place
This patch introduces bdrv_parse_cache_flags() which sets open flags
given a cache mode. Previously this was duplicated in blockdev.c and
qemu-img.c.
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
diff --git a/block.c b/block.c
index a8a013a..dbef3ae 100644
--- a/block.c
+++ b/block.c
@@ -437,6 +437,31 @@
return 0;
}
+/**
+ * Set open flags for a given cache mode
+ *
+ * Return 0 on success, -1 if the cache mode was invalid.
+ */
+int bdrv_parse_cache_flags(const char *mode, int *flags)
+{
+ *flags &= ~BDRV_O_CACHE_MASK;
+
+ if (!strcmp(mode, "off") || !strcmp(mode, "none")) {
+ *flags |= BDRV_O_NOCACHE | BDRV_O_CACHE_WB;
+ } else if (!strcmp(mode, "writeback")) {
+ *flags |= BDRV_O_CACHE_WB;
+ } else if (!strcmp(mode, "unsafe")) {
+ *flags |= BDRV_O_CACHE_WB;
+ *flags |= BDRV_O_NO_FLUSH;
+ } else if (!strcmp(mode, "writethrough")) {
+ /* this is the default */
+ } else {
+ return -1;
+ }
+
+ return 0;
+}
+
/*
* Common part for opening disk images and files
*/