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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>
This commit is contained in:
Kevin Wolf 2013-03-15 10:35:08 +01:00 committed by Stefan Hajnoczi
parent 0006383e15
commit 74c4510a3c
3 changed files with 39 additions and 1 deletions
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2
block/qcow2-cluster.c
View File

@ -668,7 +668,7 @@ int qcow2_alloc_cluster_link_l2(BlockDriverState *bs, QCowL2Meta *m)
}
/* Update L2 table. */
if (s->compatible_features & QCOW2_COMPAT_LAZY_REFCOUNTS) {
if (s->use_lazy_refcounts) {
qcow2_mark_dirty(bs);
}
if (qcow2_need_accurate_refcounts(s)) {

37
block/qcow2.c
View File

@ -285,11 +285,26 @@ static int qcow2_check(BlockDriverState *bs, BdrvCheckResult *result,
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 @@ static int qcow2_open(BlockDriverState *bs, QDict *options, int flags)
}
}
/* 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};

1
block/qcow2.h
View File

@ -173,6 +173,7 @@ typedef struct BDRVQcowState {
int flags;
int qcow_version;
bool use_lazy_refcounts;
uint64_t incompatible_features;
uint64_t compatible_features;