qcow2: Allow lazy refcounts to be enabled on the command line
qcow2 images now accept a boolean lazy_refcounts options. Use it like
this:
-drive file=test.qcow2,lazy_refcounts=on
If the option is specified on the command line, it overrides the default
specified by the qcow2 header flags that were set when creating the
image.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
diff --git a/block/qcow2.c b/block/qcow2.c
index f5e4269..ad43a13 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -285,11 +285,26 @@
return ret;
}
+static QemuOptsList qcow2_runtime_opts = {
+ .name = "qcow2",
+ .head = QTAILQ_HEAD_INITIALIZER(qcow2_runtime_opts.head),
+ .desc = {
+ {
+ .name = "lazy_refcounts",
+ .type = QEMU_OPT_BOOL,
+ .help = "Postpone refcount updates",
+ },
+ { /* end of list */ }
+ },
+};
+
static int qcow2_open(BlockDriverState *bs, QDict *options, int flags)
{
BDRVQcowState *s = bs->opaque;
int len, i, ret = 0;
QCowHeader header;
+ QemuOpts *opts;
+ Error *local_err = NULL;
uint64_t ext_end;
ret = bdrv_pread(bs->file, 0, &header, sizeof(header));
@@ -495,6 +510,28 @@
}
}
+ /* Enable lazy_refcounts according to image and command line options */
+ opts = qemu_opts_create_nofail(&qcow2_runtime_opts);
+ qemu_opts_absorb_qdict(opts, options, &local_err);
+ if (error_is_set(&local_err)) {
+ qerror_report_err(local_err);
+ error_free(local_err);
+ ret = -EINVAL;
+ goto fail;
+ }
+
+ s->use_lazy_refcounts = qemu_opt_get_bool(opts, "lazy_refcounts",
+ (s->compatible_features & QCOW2_COMPAT_LAZY_REFCOUNTS));
+
+ qemu_opts_del(opts);
+
+ if (s->use_lazy_refcounts && s->qcow_version < 3) {
+ qerror_report(ERROR_CLASS_GENERIC_ERROR, "Lazy refcounts require "
+ "a qcow2 image with at least qemu 1.1 compatibility level");
+ ret = -EINVAL;
+ goto fail;
+ }
+
#ifdef DEBUG_ALLOC
{
BdrvCheckResult result = {0};
