Il 15/03/2013 16:14, Stefan Hajnoczi ha scritto:
> From: Kevin Wolf <[email protected]>
>
> 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 <[email protected]>
> Reviewed-by: Eric Blake <[email protected]>
> Reviewed-by: Stefan Hajnoczi <[email protected]>
> Signed-off-by: Stefan Hajnoczi <[email protected]>
> ---
> block/qcow2-cluster.c | 2 +-
> block/qcow2.c | 37 +++++++++++++++++++++++++++++++++++++
> block/qcow2.h | 1 +
> 3 files changed, 39 insertions(+), 1 deletion(-)
>
> diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c
> index 56fccf9..ff9ae18 100644
> --- a/block/qcow2-cluster.c
> +++ b/block/qcow2-cluster.c
> @@ -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)) {
> 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 @@ 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);
This breaks migration with qcow2 images:
Program received signal SIGSEGV, Segmentation fault.
qdict_next_entry (first_bucket=0, qdict=0x0) at
/home/pbonzini/work/upstream/qemu/qobject/qdict.c:371
371 if (!QLIST_EMPTY(&qdict->table[i])) {
(gdb) up
#1 qdict_first (qdict=qdict@entry=0x0) at
/home/pbonzini/work/upstream/qemu/qobject/qdict.c:384
384 return qdict_next_entry(qdict, 0);
(gdb)
#2 0x00007fb8edf75ae6 in qemu_opts_absorb_qdict
(opts=opts@entry=0x7fb8f0651740, qdict=qdict@entry=0x0,
errp=errp@entry=0x7fb8edc36e80)
at /home/pbonzini/work/upstream/qemu/util/qemu-option.c:1078
1078 entry = qdict_first(qdict);
(gdb)
#3 0x00007fb8edd15074 in qcow2_open (bs=0x7fb8f041b800, options=0x0,
flags=<optimized out>) at /home/pbonzini/work/upstream/qemu/block/qcow2.c:515
515 qemu_opts_absorb_qdict(opts, options, &local_err);
(gdb)
#4 0x00007fb8edd00352 in bdrv_invalidate_cache (bs=0x7fb8f041b800) at
/home/pbonzini/work/upstream/qemu/block.c:4192
4192 bs->drv->bdrv_invalidate_cache(bs);
Paolo
> + 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};
> diff --git a/block/qcow2.h b/block/qcow2.h
> index 718b52b..103abdb 100644
> --- a/block/qcow2.h
> +++ b/block/qcow2.h
> @@ -173,6 +173,7 @@ typedef struct BDRVQcowState {
>
> int flags;
> int qcow_version;
> + bool use_lazy_refcounts;
>
> uint64_t incompatible_features;
> uint64_t compatible_features;
>
