#include "qemu/osdep.h"
#include "block/snapshot.h"
#include "block/block_int.h"
+#include "block/qdict.h"
#include "qapi/error.h"
+#include "qapi/qmp/qdict.h"
#include "qapi/qmp/qerror.h"
#include "qapi/qmp/qstring.h"
+#include "qemu/option.h"
+#include "sysemu/block-backend.h"
QemuOptsList internal_snapshot_opts = {
.name = "snapshot",
}
for (i = 0; i < nb_sns; i++) {
sn = &sn_tab[i];
- if (!strcmp(sn->id_str, name) || !strcmp(sn->name, name)) {
+ if (!strcmp(sn->name, name)) {
*sn_info = *sn;
ret = 0;
break;
return ret;
}
+/**
+ * Return a pointer to the child BDS pointer 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)
+{
+ BdrvChild **fallback;
+ 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;
+ }
+
+ 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.
+ */
+ QLIST_FOREACH(child, &bs->children, next) {
+ if (child->role & (BDRV_CHILD_DATA | BDRV_CHILD_METADATA |
+ BDRV_CHILD_FILTERED) &&
+ child != *fallback)
+ {
+ return NULL;
+ }
+ }
+
+ return fallback;
+}
+
+static BlockDriverState *bdrv_snapshot_fallback(BlockDriverState *bs)
+{
+ BdrvChild **child_ptr = bdrv_snapshot_fallback_ptr(bs);
+ return child_ptr ? (*child_ptr)->bs : NULL;
+}
+
int bdrv_can_snapshot(BlockDriverState *bs)
{
BlockDriver *drv = bs->drv;
}
if (!drv->bdrv_snapshot_create) {
- if (bs->file != NULL) {
- return bdrv_can_snapshot(bs->file->bs);
+ BlockDriverState *fallback_bs = bdrv_snapshot_fallback(bs);
+ if (fallback_bs) {
+ return bdrv_can_snapshot(fallback_bs);
}
return 0;
}
QEMUSnapshotInfo *sn_info)
{
BlockDriver *drv = bs->drv;
+ BlockDriverState *fallback_bs = bdrv_snapshot_fallback(bs);
if (!drv) {
return -ENOMEDIUM;
}
if (drv->bdrv_snapshot_create) {
return drv->bdrv_snapshot_create(bs, sn_info);
}
- if (bs->file) {
- return bdrv_snapshot_create(bs->file->bs, sn_info);
+ if (fallback_bs) {
+ return bdrv_snapshot_create(fallback_bs, sn_info);
}
return -ENOTSUP;
}
int bdrv_snapshot_goto(BlockDriverState *bs,
- const char *snapshot_id)
+ const char *snapshot_id,
+ Error **errp)
{
BlockDriver *drv = bs->drv;
+ BdrvChild **fallback_ptr;
int ret, open_ret;
if (!drv) {
+ error_setg(errp, "Block driver is closed");
return -ENOMEDIUM;
}
+
+ if (!QLIST_EMPTY(&bs->dirty_bitmaps)) {
+ error_setg(errp, "Device has active dirty bitmaps");
+ return -EBUSY;
+ }
+
if (drv->bdrv_snapshot_goto) {
- return drv->bdrv_snapshot_goto(bs, snapshot_id);
+ ret = drv->bdrv_snapshot_goto(bs, snapshot_id);
+ if (ret < 0) {
+ error_setg_errno(errp, -ret, "Failed to load snapshot");
+ }
+ return ret;
}
- if (bs->file) {
- BlockDriverState *file;
- QDict *options = qdict_clone_shallow(bs->options);
+ fallback_ptr = bdrv_snapshot_fallback_ptr(bs);
+ if (fallback_ptr) {
+ 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);
+
+ options = qdict_clone_shallow(bs->options);
- file = bs->file->bs;
/* Prevent it from getting deleted when detached from bs */
- bdrv_ref(file);
+ bdrv_ref(fallback_bs);
- qdict_extract_subqdict(options, &file_options, "file.");
- QDECREF(file_options);
- qdict_put_str(options, "file", bdrv_get_node_name(file));
+ qdict_extract_subqdict(options, &file_options, subqdict_prefix);
+ qobject_unref(file_options);
+ g_free(subqdict_prefix);
- drv->bdrv_close(bs);
- bdrv_unref_child(bs, bs->file);
- bs->file = NULL;
+ qdict_put_str(options, (*fallback_ptr)->name,
+ bdrv_get_node_name(fallback_bs));
- ret = bdrv_snapshot_goto(file, snapshot_id);
- open_ret = drv->bdrv_open(bs, options, bs->open_flags, NULL);
- QDECREF(options);
+ if (drv->bdrv_close) {
+ drv->bdrv_close(bs);
+ }
+
+ bdrv_unref_child(bs, *fallback_ptr);
+ *fallback_ptr = NULL;
+
+ ret = bdrv_snapshot_goto(fallback_bs, snapshot_id, errp);
+ open_ret = drv->bdrv_open(bs, options, bs->open_flags, &local_err);
+ qobject_unref(options);
if (open_ret < 0) {
- bdrv_unref(file);
+ bdrv_unref(fallback_bs);
bs->drv = NULL;
- return open_ret;
+ /* A bdrv_snapshot_goto() error takes precedence */
+ error_propagate(errp, local_err);
+ return ret < 0 ? ret : open_ret;
}
- assert(bs->file->bs == file);
- bdrv_unref(file);
+ assert(fallback_bs == (*fallback_ptr)->bs);
+ bdrv_unref(fallback_bs);
return ret;
}
+ error_setg(errp, "Block driver does not support snapshots");
return -ENOTSUP;
}
Error **errp)
{
BlockDriver *drv = bs->drv;
+ BlockDriverState *fallback_bs = bdrv_snapshot_fallback(bs);
int ret;
if (!drv) {
if (drv->bdrv_snapshot_delete) {
ret = drv->bdrv_snapshot_delete(bs, snapshot_id, name, errp);
- } else if (bs->file) {
- ret = bdrv_snapshot_delete(bs->file->bs, snapshot_id, name, errp);
+ } else if (fallback_bs) {
+ ret = bdrv_snapshot_delete(fallback_bs, snapshot_id, name, errp);
} else {
error_setg(errp, "Block format '%s' used by device '%s' "
"does not support internal snapshot deletion",
return ret;
}
-int bdrv_snapshot_delete_by_id_or_name(BlockDriverState *bs,
- const char *id_or_name,
- Error **errp)
-{
- int ret;
- Error *local_err = NULL;
-
- ret = bdrv_snapshot_delete(bs, id_or_name, NULL, &local_err);
- if (ret == -ENOENT || ret == -EINVAL) {
- error_free(local_err);
- local_err = NULL;
- ret = bdrv_snapshot_delete(bs, NULL, id_or_name, &local_err);
- }
-
- if (ret < 0) {
- error_propagate(errp, local_err);
- }
- return ret;
-}
-
int bdrv_snapshot_list(BlockDriverState *bs,
QEMUSnapshotInfo **psn_info)
{
BlockDriver *drv = bs->drv;
+ BlockDriverState *fallback_bs = bdrv_snapshot_fallback(bs);
if (!drv) {
return -ENOMEDIUM;
}
if (drv->bdrv_snapshot_list) {
return drv->bdrv_snapshot_list(bs, psn_info);
}
- if (bs->file) {
- return bdrv_snapshot_list(bs->file->bs, psn_info);
+ if (fallback_bs) {
+ return bdrv_snapshot_list(fallback_bs, psn_info);
}
return -ENOTSUP;
}
}
+static int bdrv_all_get_snapshot_devices(bool has_devices, strList *devices,
+ GList **all_bdrvs,
+ Error **errp)
+{
+ g_autoptr(GList) bdrvs = NULL;
+
+ if (has_devices) {
+ if (!devices) {
+ error_setg(errp, "At least one device is required for snapshot");
+ return -1;
+ }
+
+ while (devices) {
+ BlockDriverState *bs = bdrv_find_node(devices->value);
+ if (!bs) {
+ error_setg(errp, "No block device node '%s'", devices->value);
+ return -1;
+ }
+ bdrvs = g_list_append(bdrvs, bs);
+ devices = devices->next;
+ }
+ } else {
+ BlockDriverState *bs;
+ BdrvNextIterator it;
+ for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
+ bdrvs = g_list_append(bdrvs, bs);
+ }
+ }
+
+ *all_bdrvs = g_steal_pointer(&bdrvs);
+ return 0;
+}
+
+
+static bool bdrv_all_snapshots_includes_bs(BlockDriverState *bs)
+{
+ if (!bdrv_is_inserted(bs) || bdrv_is_read_only(bs)) {
+ return false;
+ }
+
+ /* Include all nodes that are either in use by a BlockBackend, or that
+ * aren't attached to any node, but owned by the monitor. */
+ return bdrv_has_blk(bs) || QLIST_EMPTY(&bs->parents);
+}
+
/* Group operations. All block drivers are involved.
* These functions will properly handle dataplane (take aio_context_acquire
* when appropriate for appropriate block drivers) */
-bool bdrv_all_can_snapshot(BlockDriverState **first_bad_bs)
+bool bdrv_all_can_snapshot(bool has_devices, strList *devices,
+ Error **errp)
{
- bool ok = true;
- BlockDriverState *bs;
- BdrvNextIterator it;
+ g_autoptr(GList) bdrvs = NULL;
+ GList *iterbdrvs;
+
+ if (bdrv_all_get_snapshot_devices(has_devices, devices, &bdrvs, errp) < 0) {
+ return false;
+ }
- for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
+ iterbdrvs = bdrvs;
+ while (iterbdrvs) {
+ BlockDriverState *bs = iterbdrvs->data;
AioContext *ctx = bdrv_get_aio_context(bs);
+ bool ok = true;
aio_context_acquire(ctx);
- if (bdrv_is_inserted(bs) && !bdrv_is_read_only(bs)) {
+ if (devices || bdrv_all_snapshots_includes_bs(bs)) {
ok = bdrv_can_snapshot(bs);
}
aio_context_release(ctx);
if (!ok) {
- goto fail;
+ error_setg(errp, "Device '%s' is writable but does not support "
+ "snapshots", bdrv_get_device_or_node_name(bs));
+ return false;
}
+
+ iterbdrvs = iterbdrvs->next;
}
-fail:
- *first_bad_bs = bs;
- return ok;
+ return true;
}
-int bdrv_all_delete_snapshot(const char *name, BlockDriverState **first_bad_bs,
- Error **err)
+int bdrv_all_delete_snapshot(const char *name,
+ bool has_devices, strList *devices,
+ Error **errp)
{
- int ret = 0;
- BlockDriverState *bs;
- BdrvNextIterator it;
- QEMUSnapshotInfo sn1, *snapshot = &sn1;
+ g_autoptr(GList) bdrvs = NULL;
+ GList *iterbdrvs;
- for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
+ if (bdrv_all_get_snapshot_devices(has_devices, devices, &bdrvs, errp) < 0) {
+ return -1;
+ }
+
+ iterbdrvs = bdrvs;
+ while (iterbdrvs) {
+ BlockDriverState *bs = iterbdrvs->data;
AioContext *ctx = bdrv_get_aio_context(bs);
+ QEMUSnapshotInfo sn1, *snapshot = &sn1;
+ int ret = 0;
aio_context_acquire(ctx);
- if (bdrv_can_snapshot(bs) &&
- bdrv_snapshot_find(bs, snapshot, name) >= 0) {
- ret = bdrv_snapshot_delete_by_id_or_name(bs, name, err);
+ if ((devices || bdrv_all_snapshots_includes_bs(bs)) &&
+ bdrv_snapshot_find(bs, snapshot, name) >= 0)
+ {
+ ret = bdrv_snapshot_delete(bs, snapshot->id_str,
+ snapshot->name, errp);
}
aio_context_release(ctx);
if (ret < 0) {
- goto fail;
+ error_prepend(errp, "Could not delete snapshot '%s' on '%s': ",
+ name, bdrv_get_device_or_node_name(bs));
+ return -1;
}
+
+ iterbdrvs = iterbdrvs->next;
}
-fail:
- *first_bad_bs = bs;
- return ret;
+ return 0;
}
-int bdrv_all_goto_snapshot(const char *name, BlockDriverState **first_bad_bs)
+int bdrv_all_goto_snapshot(const char *name,
+ bool has_devices, strList *devices,
+ Error **errp)
{
- int err = 0;
- BlockDriverState *bs;
- BdrvNextIterator it;
+ g_autoptr(GList) bdrvs = NULL;
+ GList *iterbdrvs;
- for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
+ if (bdrv_all_get_snapshot_devices(has_devices, devices, &bdrvs, errp) < 0) {
+ return -1;
+ }
+
+ iterbdrvs = bdrvs;
+ while (iterbdrvs) {
+ BlockDriverState *bs = iterbdrvs->data;
AioContext *ctx = bdrv_get_aio_context(bs);
+ int ret = 0;
aio_context_acquire(ctx);
- if (bdrv_can_snapshot(bs)) {
- err = bdrv_snapshot_goto(bs, name);
+ if (devices || bdrv_all_snapshots_includes_bs(bs)) {
+ ret = bdrv_snapshot_goto(bs, name, errp);
}
aio_context_release(ctx);
- if (err < 0) {
- goto fail;
+ if (ret < 0) {
+ error_prepend(errp, "Could not load snapshot '%s' on '%s': ",
+ name, bdrv_get_device_or_node_name(bs));
+ return -1;
}
+
+ iterbdrvs = iterbdrvs->next;
}
-fail:
- *first_bad_bs = bs;
- return err;
+ return 0;
}
-int bdrv_all_find_snapshot(const char *name, BlockDriverState **first_bad_bs)
+int bdrv_all_has_snapshot(const char *name,
+ bool has_devices, strList *devices,
+ Error **errp)
{
- QEMUSnapshotInfo sn;
- int err = 0;
- BlockDriverState *bs;
- BdrvNextIterator it;
+ g_autoptr(GList) bdrvs = NULL;
+ GList *iterbdrvs;
+
+ if (bdrv_all_get_snapshot_devices(has_devices, devices, &bdrvs, errp) < 0) {
+ return -1;
+ }
- for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
+ iterbdrvs = bdrvs;
+ while (iterbdrvs) {
+ BlockDriverState *bs = iterbdrvs->data;
AioContext *ctx = bdrv_get_aio_context(bs);
+ QEMUSnapshotInfo sn;
+ int ret = 0;
aio_context_acquire(ctx);
- if (bdrv_can_snapshot(bs)) {
- err = bdrv_snapshot_find(bs, &sn, name);
+ if (devices || bdrv_all_snapshots_includes_bs(bs)) {
+ ret = bdrv_snapshot_find(bs, &sn, name);
}
aio_context_release(ctx);
- if (err < 0) {
- goto fail;
+ if (ret < 0) {
+ if (ret == -ENOENT) {
+ return 0;
+ } else {
+ error_setg_errno(errp, errno,
+ "Could not check snapshot '%s' on '%s'",
+ name, bdrv_get_device_or_node_name(bs));
+ return -1;
+ }
}
+
+ iterbdrvs = iterbdrvs->next;
}
-fail:
- *first_bad_bs = bs;
- return err;
+ return 1;
}
int bdrv_all_create_snapshot(QEMUSnapshotInfo *sn,
BlockDriverState *vm_state_bs,
uint64_t vm_state_size,
- BlockDriverState **first_bad_bs)
+ bool has_devices, strList *devices,
+ Error **errp)
{
- int err = 0;
- BlockDriverState *bs;
- BdrvNextIterator it;
+ g_autoptr(GList) bdrvs = NULL;
+ GList *iterbdrvs;
+
+ if (bdrv_all_get_snapshot_devices(has_devices, devices, &bdrvs, errp) < 0) {
+ return -1;
+ }
- for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
+ iterbdrvs = bdrvs;
+ while (iterbdrvs) {
+ BlockDriverState *bs = iterbdrvs->data;
AioContext *ctx = bdrv_get_aio_context(bs);
+ int ret = 0;
aio_context_acquire(ctx);
if (bs == vm_state_bs) {
sn->vm_state_size = vm_state_size;
- err = bdrv_snapshot_create(bs, sn);
- } else if (bdrv_can_snapshot(bs)) {
+ ret = bdrv_snapshot_create(bs, sn);
+ } else if (devices || bdrv_all_snapshots_includes_bs(bs)) {
sn->vm_state_size = 0;
- err = bdrv_snapshot_create(bs, sn);
+ ret = bdrv_snapshot_create(bs, sn);
}
aio_context_release(ctx);
- if (err < 0) {
- goto fail;
+ if (ret < 0) {
+ error_setg(errp, "Could not create snapshot '%s' on '%s'",
+ sn->name, bdrv_get_device_or_node_name(bs));
+ return -1;
}
+
+ iterbdrvs = iterbdrvs->next;
}
-fail:
- *first_bad_bs = bs;
- return err;
+ return 0;
}
-BlockDriverState *bdrv_all_find_vmstate_bs(void)
+
+BlockDriverState *bdrv_all_find_vmstate_bs(const char *vmstate_bs,
+ bool has_devices, strList *devices,
+ Error **errp)
{
- BlockDriverState *bs;
- BdrvNextIterator it;
+ g_autoptr(GList) bdrvs = NULL;
+ GList *iterbdrvs;
- for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
+ if (bdrv_all_get_snapshot_devices(has_devices, devices, &bdrvs, errp) < 0) {
+ return NULL;
+ }
+
+ iterbdrvs = bdrvs;
+ while (iterbdrvs) {
+ BlockDriverState *bs = iterbdrvs->data;
AioContext *ctx = bdrv_get_aio_context(bs);
- bool found;
+ bool found = false;
aio_context_acquire(ctx);
- found = bdrv_can_snapshot(bs);
+ found = (devices || bdrv_all_snapshots_includes_bs(bs)) &&
+ bdrv_can_snapshot(bs);
aio_context_release(ctx);
- if (found) {
- break;
+ if (vmstate_bs) {
+ if (g_str_equal(vmstate_bs,
+ bdrv_get_node_name(bs))) {
+ if (found) {
+ return bs;
+ } else {
+ error_setg(errp,
+ "vmstate block device '%s' does not support snapshots",
+ vmstate_bs);
+ return NULL;
+ }
+ }
+ } else if (found) {
+ return bs;
}
+
+ iterbdrvs = iterbdrvs->next;
+ }
+
+ if (vmstate_bs) {
+ error_setg(errp,
+ "vmstate block device '%s' does not exist", vmstate_bs);
+ } else {
+ error_setg(errp,
+ "no block device can store vmstate for snapshot");
}
- return bs;
+ return NULL;
}
projects / qemu.git / blobdiff