qcow2: Make qcow2_update_options() suitable for transactions
Before we can allow updating options at runtime with bdrv_reopen(), we
need to split the function into prepare/commit/abort parts.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
diff --git a/block/qcow2.c b/block/qcow2.c
index 374a56d..64ba3cb 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -589,18 +589,25 @@
}
}
-static int qcow2_update_options(BlockDriverState *bs, QDict *options,
- int flags, Error **errp)
+typedef struct Qcow2ReopenState {
+ Qcow2Cache *l2_table_cache;
+ Qcow2Cache *refcount_block_cache;
+ bool use_lazy_refcounts;
+ int overlap_check;
+ bool discard_passthrough[QCOW2_DISCARD_MAX];
+ uint64_t cache_clean_interval;
+} Qcow2ReopenState;
+
+static int qcow2_update_options_prepare(BlockDriverState *bs,
+ Qcow2ReopenState *r,
+ QDict *options, int flags,
+ Error **errp)
{
BDRVQcow2State *s = bs->opaque;
QemuOpts *opts = NULL;
const char *opt_overlap_check, *opt_overlap_check_template;
int overlap_check_template = 0;
uint64_t l2_cache_size, refcount_cache_size;
- Qcow2Cache *l2_table_cache = NULL;
- Qcow2Cache *refcount_block_cache = NULL;
- uint64_t cache_clean_interval;
- bool use_lazy_refcounts;
int i;
Error *local_err = NULL;
int ret;
@@ -643,27 +650,27 @@
}
/* alloc L2 table/refcount block cache */
- l2_table_cache = qcow2_cache_create(bs, l2_cache_size);
- refcount_block_cache = qcow2_cache_create(bs, refcount_cache_size);
- if (l2_table_cache == NULL || refcount_block_cache == NULL) {
+ r->l2_table_cache = qcow2_cache_create(bs, l2_cache_size);
+ r->refcount_block_cache = qcow2_cache_create(bs, refcount_cache_size);
+ if (r->l2_table_cache == NULL || r->refcount_block_cache == NULL) {
error_setg(errp, "Could not allocate metadata caches");
ret = -ENOMEM;
goto fail;
}
/* New interval for cache cleanup timer */
- cache_clean_interval =
+ r->cache_clean_interval =
qemu_opt_get_number(opts, QCOW2_OPT_CACHE_CLEAN_INTERVAL, 0);
- if (cache_clean_interval > UINT_MAX) {
+ if (r->cache_clean_interval > UINT_MAX) {
error_setg(errp, "Cache clean interval too big");
ret = -EINVAL;
goto fail;
}
/* Enable lazy_refcounts according to image and command line options */
- use_lazy_refcounts = qemu_opt_get_bool(opts, QCOW2_OPT_LAZY_REFCOUNTS,
+ r->use_lazy_refcounts = qemu_opt_get_bool(opts, QCOW2_OPT_LAZY_REFCOUNTS,
(s->compatible_features & QCOW2_COMPAT_LAZY_REFCOUNTS));
- if (use_lazy_refcounts && s->qcow_version < 3) {
+ if (r->use_lazy_refcounts && s->qcow_version < 3) {
error_setg(errp, "Lazy refcounts require a qcow2 image with at least "
"qemu 1.1 compatibility level");
ret = -EINVAL;
@@ -702,49 +709,75 @@
goto fail;
}
- /*
- * Start updating fields in BDRVQcow2State.
- * After this point no failure is allowed any more.
- */
- s->overlap_check = 0;
+ r->overlap_check = 0;
for (i = 0; i < QCOW2_OL_MAX_BITNR; i++) {
/* overlap-check defines a template bitmask, but every flag may be
* overwritten through the associated boolean option */
- s->overlap_check |=
+ r->overlap_check |=
qemu_opt_get_bool(opts, overlap_bool_option_names[i],
overlap_check_template & (1 << i)) << i;
}
- s->l2_table_cache = l2_table_cache;
- s->refcount_block_cache = refcount_block_cache;
-
- s->use_lazy_refcounts = use_lazy_refcounts;
-
- s->discard_passthrough[QCOW2_DISCARD_NEVER] = false;
- s->discard_passthrough[QCOW2_DISCARD_ALWAYS] = true;
- s->discard_passthrough[QCOW2_DISCARD_REQUEST] =
+ r->discard_passthrough[QCOW2_DISCARD_NEVER] = false;
+ r->discard_passthrough[QCOW2_DISCARD_ALWAYS] = true;
+ r->discard_passthrough[QCOW2_DISCARD_REQUEST] =
qemu_opt_get_bool(opts, QCOW2_OPT_DISCARD_REQUEST,
flags & BDRV_O_UNMAP);
- s->discard_passthrough[QCOW2_DISCARD_SNAPSHOT] =
+ r->discard_passthrough[QCOW2_DISCARD_SNAPSHOT] =
qemu_opt_get_bool(opts, QCOW2_OPT_DISCARD_SNAPSHOT, true);
- s->discard_passthrough[QCOW2_DISCARD_OTHER] =
+ r->discard_passthrough[QCOW2_DISCARD_OTHER] =
qemu_opt_get_bool(opts, QCOW2_OPT_DISCARD_OTHER, false);
- s->cache_clean_interval = cache_clean_interval;
- cache_clean_timer_init(bs, bdrv_get_aio_context(bs));
-
ret = 0;
fail:
- if (ret < 0) {
- if (l2_table_cache) {
- qcow2_cache_destroy(bs, l2_table_cache);
- }
- if (refcount_block_cache) {
- qcow2_cache_destroy(bs, refcount_block_cache);
- }
- }
qemu_opts_del(opts);
opts = NULL;
+ return ret;
+}
+
+static void qcow2_update_options_commit(BlockDriverState *bs,
+ Qcow2ReopenState *r)
+{
+ BDRVQcow2State *s = bs->opaque;
+ int i;
+
+ s->l2_table_cache = r->l2_table_cache;
+ s->refcount_block_cache = r->refcount_block_cache;
+
+ s->overlap_check = r->overlap_check;
+ s->use_lazy_refcounts = r->use_lazy_refcounts;
+
+ for (i = 0; i < QCOW2_DISCARD_MAX; i++) {
+ s->discard_passthrough[i] = r->discard_passthrough[i];
+ }
+
+ s->cache_clean_interval = r->cache_clean_interval;
+ cache_clean_timer_init(bs, bdrv_get_aio_context(bs));
+}
+
+static void qcow2_update_options_abort(BlockDriverState *bs,
+ Qcow2ReopenState *r)
+{
+ if (r->l2_table_cache) {
+ qcow2_cache_destroy(bs, r->l2_table_cache);
+ }
+ if (r->refcount_block_cache) {
+ qcow2_cache_destroy(bs, r->refcount_block_cache);
+ }
+}
+
+static int qcow2_update_options(BlockDriverState *bs, QDict *options,
+ int flags, Error **errp)
+{
+ Qcow2ReopenState r = {};
+ int ret;
+
+ ret = qcow2_update_options_prepare(bs, &r, options, flags, errp);
+ if (ret >= 0) {
+ qcow2_update_options_commit(bs, &r);
+ } else {
+ qcow2_update_options_abort(bs, &r);
+ }
return ret;
}
