QEMUSnapshotInfo *sn_tab, *sn;
int nb_sns, i, ret;
+ GLOBAL_STATE_CODE();
+
ret = -ENOENT;
nb_sns = bdrv_snapshot_list(bs, &sn_tab);
if (nb_sns < 0) {
bool ret = false;
assert(id || name);
+ GLOBAL_STATE_CODE();
nb_sns = bdrv_snapshot_list(bs, &sn_tab);
if (nb_sns < 0) {
}
/**
- * Return a pointer to the child BDS pointer to which we can fall
+ * Return a pointer to child of given BDS to which we can fall
* back if the given BDS does not support snapshots.
* Return NULL if there is no BDS to (safely) fall back to.
- *
- * We need to return an indirect pointer because bdrv_snapshot_goto()
- * has to modify the BdrvChild pointer.
*/
-static BdrvChild **bdrv_snapshot_fallback_ptr(BlockDriverState *bs)
+static BdrvChild * GRAPH_RDLOCK
+bdrv_snapshot_fallback_child(BlockDriverState *bs)
{
- BdrvChild **fallback;
+ BdrvChild *fallback = bdrv_primary_child(bs);
BdrvChild *child;
- /*
- * The only BdrvChild pointers that are safe to modify (and which
- * we can thus return a reference to) are bs->file and
- * bs->backing.
- */
- fallback = &bs->file;
- if (!*fallback && bs->drv && bs->drv->is_filter) {
- fallback = &bs->backing;
- }
+ GLOBAL_STATE_CODE();
+ assert_bdrv_graph_readable();
- if (!*fallback) {
+ /* We allow fallback only to primary child */
+ if (!fallback) {
return NULL;
}
/*
* Check that there are no other children that would need to be
* snapshotted. If there are, it is not safe to fall back to
- * *fallback.
+ * fallback.
*/
QLIST_FOREACH(child, &bs->children, next) {
if (child->role & (BDRV_CHILD_DATA | BDRV_CHILD_METADATA |
BDRV_CHILD_FILTERED) &&
- child != *fallback)
+ child != fallback)
{
return NULL;
}
return fallback;
}
-static BlockDriverState *bdrv_snapshot_fallback(BlockDriverState *bs)
+static BlockDriverState * GRAPH_RDLOCK
+bdrv_snapshot_fallback(BlockDriverState *bs)
{
- BdrvChild **child_ptr = bdrv_snapshot_fallback_ptr(bs);
- return child_ptr ? (*child_ptr)->bs : NULL;
+ GLOBAL_STATE_CODE();
+ return child_bs(bdrv_snapshot_fallback_child(bs));
}
int bdrv_can_snapshot(BlockDriverState *bs)
{
BlockDriver *drv = bs->drv;
+ GLOBAL_STATE_CODE();
if (!drv || !bdrv_is_inserted(bs) || bdrv_is_read_only(bs)) {
return 0;
}
{
BlockDriver *drv = bs->drv;
BlockDriverState *fallback_bs = bdrv_snapshot_fallback(bs);
+
+ GLOBAL_STATE_CODE();
+
if (!drv) {
return -ENOMEDIUM;
}
Error **errp)
{
BlockDriver *drv = bs->drv;
- BdrvChild **fallback_ptr;
+ BdrvChild *fallback;
int ret, open_ret;
+ GLOBAL_STATE_CODE();
+
if (!drv) {
error_setg(errp, "Block driver is closed");
return -ENOMEDIUM;
return ret;
}
- fallback_ptr = bdrv_snapshot_fallback_ptr(bs);
- if (fallback_ptr) {
+ bdrv_graph_rdlock_main_loop();
+ fallback = bdrv_snapshot_fallback_child(bs);
+ bdrv_graph_rdunlock_main_loop();
+
+ if (fallback) {
QDict *options;
QDict *file_options;
Error *local_err = NULL;
- BlockDriverState *fallback_bs = (*fallback_ptr)->bs;
- char *subqdict_prefix = g_strdup_printf("%s.", (*fallback_ptr)->name);
+ BlockDriverState *fallback_bs = fallback->bs;
+ char *subqdict_prefix = g_strdup_printf("%s.", fallback->name);
options = qdict_clone_shallow(bs->options);
qobject_unref(file_options);
g_free(subqdict_prefix);
- qdict_put_str(options, (*fallback_ptr)->name,
+ /* Force .bdrv_open() below to re-attach fallback_bs on fallback */
+ qdict_put_str(options, fallback->name,
bdrv_get_node_name(fallback_bs));
+ /* Now close bs, apply the snapshot on fallback_bs, and re-open bs */
if (drv->bdrv_close) {
drv->bdrv_close(bs);
}
- bdrv_unref_child(bs, *fallback_ptr);
- *fallback_ptr = NULL;
+ /* .bdrv_open() will re-attach it */
+ bdrv_graph_wrlock(NULL);
+ bdrv_unref_child(bs, fallback);
+ bdrv_graph_wrunlock();
ret = bdrv_snapshot_goto(fallback_bs, snapshot_id, errp);
open_ret = drv->bdrv_open(bs, options, bs->open_flags, &local_err);
return ret < 0 ? ret : open_ret;
}
- assert(fallback_bs == (*fallback_ptr)->bs);
+ /*
+ * fallback was a primary child. It was closed above and set to NULL,
+ * but the .bdrv_open() call has opened it again, because we set the
+ * respective option (with the qdict_put_str() call above).
+ * Assert that .bdrv_open() has attached the right BDS as primary child.
+ */
+ bdrv_graph_rdlock_main_loop();
+ assert(bdrv_primary_bs(bs) == fallback_bs);
+ bdrv_graph_rdunlock_main_loop();
+
bdrv_unref(fallback_bs);
return ret;
}
BlockDriverState *fallback_bs = bdrv_snapshot_fallback(bs);
int ret;
+ GLOBAL_STATE_CODE();
+
if (!drv) {
error_setg(errp, QERR_DEVICE_HAS_NO_MEDIUM, bdrv_get_device_name(bs));
return -ENOMEDIUM;
int bdrv_snapshot_list(BlockDriverState *bs,
QEMUSnapshotInfo **psn_info)
{
+ GLOBAL_STATE_CODE();
+ GRAPH_RDLOCK_GUARD_MAINLOOP();
+
BlockDriver *drv = bs->drv;
BlockDriverState *fallback_bs = bdrv_snapshot_fallback(bs);
+
if (!drv) {
return -ENOMEDIUM;
}
{
BlockDriver *drv = bs->drv;
+ GLOBAL_STATE_CODE();
+ GRAPH_RDLOCK_GUARD_MAINLOOP();
+
if (!drv) {
error_setg(errp, QERR_DEVICE_HAS_NO_MEDIUM, bdrv_get_device_name(bs));
return -ENOMEDIUM;
int ret;
Error *local_err = NULL;
+ GLOBAL_STATE_CODE();
+
ret = bdrv_snapshot_load_tmp(bs, id_or_name, NULL, &local_err);
if (ret == -ENOENT || ret == -EINVAL) {
error_free(local_err);
}
-static int bdrv_all_get_snapshot_devices(bool has_devices, strList *devices,
- GList **all_bdrvs,
- Error **errp)
+static int GRAPH_RDLOCK
+bdrv_all_get_snapshot_devices(bool has_devices, strList *devices,
+ GList **all_bdrvs, Error **errp)
{
g_autoptr(GList) bdrvs = NULL;
}
-static bool bdrv_all_snapshots_includes_bs(BlockDriverState *bs)
+static bool GRAPH_RDLOCK bdrv_all_snapshots_includes_bs(BlockDriverState *bs)
{
+ GLOBAL_STATE_CODE();
+ assert_bdrv_graph_readable();
+
if (!bdrv_is_inserted(bs) || bdrv_is_read_only(bs)) {
return false;
}
g_autoptr(GList) bdrvs = NULL;
GList *iterbdrvs;
+ GLOBAL_STATE_CODE();
+ GRAPH_RDLOCK_GUARD_MAINLOOP();
+
if (bdrv_all_get_snapshot_devices(has_devices, devices, &bdrvs, errp) < 0) {
return false;
}
g_autoptr(GList) bdrvs = NULL;
GList *iterbdrvs;
+ GLOBAL_STATE_CODE();
+ GRAPH_RDLOCK_GUARD_MAINLOOP();
+
if (bdrv_all_get_snapshot_devices(has_devices, devices, &bdrvs, errp) < 0) {
return -1;
}
{
g_autoptr(GList) bdrvs = NULL;
GList *iterbdrvs;
+ int ret;
- if (bdrv_all_get_snapshot_devices(has_devices, devices, &bdrvs, errp) < 0) {
+ GLOBAL_STATE_CODE();
+
+ bdrv_graph_rdlock_main_loop();
+ ret = bdrv_all_get_snapshot_devices(has_devices, devices, &bdrvs, errp);
+ bdrv_graph_rdunlock_main_loop();
+
+ if (ret < 0) {
return -1;
}
while (iterbdrvs) {
BlockDriverState *bs = iterbdrvs->data;
AioContext *ctx = bdrv_get_aio_context(bs);
- int ret = 0;
+ bool all_snapshots_includes_bs;
aio_context_acquire(ctx);
- if (devices || bdrv_all_snapshots_includes_bs(bs)) {
- ret = bdrv_snapshot_goto(bs, name, errp);
- }
+ bdrv_graph_rdlock_main_loop();
+ all_snapshots_includes_bs = bdrv_all_snapshots_includes_bs(bs);
+ bdrv_graph_rdunlock_main_loop();
+
+ ret = (devices || all_snapshots_includes_bs) ?
+ bdrv_snapshot_goto(bs, name, errp) : 0;
aio_context_release(ctx);
if (ret < 0) {
+ bdrv_graph_rdlock_main_loop();
error_prepend(errp, "Could not load snapshot '%s' on '%s': ",
name, bdrv_get_device_or_node_name(bs));
+ bdrv_graph_rdunlock_main_loop();
return -1;
}
g_autoptr(GList) bdrvs = NULL;
GList *iterbdrvs;
+ GLOBAL_STATE_CODE();
+ GRAPH_RDLOCK_GUARD_MAINLOOP();
+
if (bdrv_all_get_snapshot_devices(has_devices, devices, &bdrvs, errp) < 0) {
return -1;
}
g_autoptr(GList) bdrvs = NULL;
GList *iterbdrvs;
+ GLOBAL_STATE_CODE();
+ GRAPH_RDLOCK_GUARD_MAINLOOP();
+
if (bdrv_all_get_snapshot_devices(has_devices, devices, &bdrvs, errp) < 0) {
return -1;
}
g_autoptr(GList) bdrvs = NULL;
GList *iterbdrvs;
+ GLOBAL_STATE_CODE();
+ GRAPH_RDLOCK_GUARD_MAINLOOP();
+
if (bdrv_all_get_snapshot_devices(has_devices, devices, &bdrvs, errp) < 0) {
return NULL;
}
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