358 lines
11 KiB
C
358 lines
11 KiB
C
/*
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* Block layer snapshot related functions
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*
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* Copyright (c) 2003-2008 Fabrice Bellard
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#include "block/snapshot.h"
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#include "block/block_int.h"
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QemuOptsList internal_snapshot_opts = {
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.name = "snapshot",
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.head = QTAILQ_HEAD_INITIALIZER(internal_snapshot_opts.head),
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.desc = {
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{
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.name = SNAPSHOT_OPT_ID,
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.type = QEMU_OPT_STRING,
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.help = "snapshot id"
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},{
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.name = SNAPSHOT_OPT_NAME,
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.type = QEMU_OPT_STRING,
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.help = "snapshot name"
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},{
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/* end of list */
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}
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},
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};
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int bdrv_snapshot_find(BlockDriverState *bs, QEMUSnapshotInfo *sn_info,
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const char *name)
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{
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QEMUSnapshotInfo *sn_tab, *sn;
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int nb_sns, i, ret;
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ret = -ENOENT;
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nb_sns = bdrv_snapshot_list(bs, &sn_tab);
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if (nb_sns < 0) {
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return ret;
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}
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for (i = 0; i < nb_sns; i++) {
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sn = &sn_tab[i];
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if (!strcmp(sn->id_str, name) || !strcmp(sn->name, name)) {
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*sn_info = *sn;
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ret = 0;
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break;
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}
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}
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g_free(sn_tab);
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return ret;
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}
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/**
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* Look up an internal snapshot by @id and @name.
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* @bs: block device to search
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* @id: unique snapshot ID, or NULL
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* @name: snapshot name, or NULL
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* @sn_info: location to store information on the snapshot found
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* @errp: location to store error, will be set only for exception
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*
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* This function will traverse snapshot list in @bs to search the matching
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* one, @id and @name are the matching condition:
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* If both @id and @name are specified, find the first one with id @id and
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* name @name.
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* If only @id is specified, find the first one with id @id.
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* If only @name is specified, find the first one with name @name.
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* if none is specified, abort().
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*
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* Returns: true when a snapshot is found and @sn_info will be filled, false
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* when error or not found. If all operation succeed but no matching one is
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* found, @errp will NOT be set.
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*/
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bool bdrv_snapshot_find_by_id_and_name(BlockDriverState *bs,
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const char *id,
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const char *name,
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QEMUSnapshotInfo *sn_info,
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Error **errp)
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{
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QEMUSnapshotInfo *sn_tab, *sn;
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int nb_sns, i;
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bool ret = false;
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assert(id || name);
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nb_sns = bdrv_snapshot_list(bs, &sn_tab);
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if (nb_sns < 0) {
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error_setg_errno(errp, -nb_sns, "Failed to get a snapshot list");
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return false;
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} else if (nb_sns == 0) {
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return false;
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}
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if (id && name) {
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for (i = 0; i < nb_sns; i++) {
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sn = &sn_tab[i];
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if (!strcmp(sn->id_str, id) && !strcmp(sn->name, name)) {
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*sn_info = *sn;
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ret = true;
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break;
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}
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}
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} else if (id) {
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for (i = 0; i < nb_sns; i++) {
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sn = &sn_tab[i];
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if (!strcmp(sn->id_str, id)) {
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*sn_info = *sn;
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ret = true;
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break;
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}
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}
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} else if (name) {
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for (i = 0; i < nb_sns; i++) {
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sn = &sn_tab[i];
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if (!strcmp(sn->name, name)) {
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*sn_info = *sn;
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ret = true;
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break;
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}
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}
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}
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g_free(sn_tab);
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return ret;
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}
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int bdrv_can_snapshot(BlockDriverState *bs)
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{
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BlockDriver *drv = bs->drv;
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if (!drv || !bdrv_is_inserted(bs) || bdrv_is_read_only(bs)) {
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return 0;
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}
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if (!drv->bdrv_snapshot_create) {
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if (bs->file != NULL) {
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return bdrv_can_snapshot(bs->file);
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}
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return 0;
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}
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return 1;
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}
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int bdrv_snapshot_create(BlockDriverState *bs,
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QEMUSnapshotInfo *sn_info)
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{
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BlockDriver *drv = bs->drv;
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if (!drv) {
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return -ENOMEDIUM;
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}
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if (drv->bdrv_snapshot_create) {
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return drv->bdrv_snapshot_create(bs, sn_info);
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}
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if (bs->file) {
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return bdrv_snapshot_create(bs->file, sn_info);
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}
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return -ENOTSUP;
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}
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int bdrv_snapshot_goto(BlockDriverState *bs,
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const char *snapshot_id)
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{
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BlockDriver *drv = bs->drv;
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int ret, open_ret;
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if (!drv) {
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return -ENOMEDIUM;
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}
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if (drv->bdrv_snapshot_goto) {
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return drv->bdrv_snapshot_goto(bs, snapshot_id);
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}
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if (bs->file) {
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drv->bdrv_close(bs);
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ret = bdrv_snapshot_goto(bs->file, snapshot_id);
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open_ret = drv->bdrv_open(bs, NULL, bs->open_flags, NULL);
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if (open_ret < 0) {
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bdrv_unref(bs->file);
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bs->drv = NULL;
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return open_ret;
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}
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return ret;
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}
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return -ENOTSUP;
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}
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/**
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* Delete an internal snapshot by @snapshot_id and @name.
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* @bs: block device used in the operation
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* @snapshot_id: unique snapshot ID, or NULL
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* @name: snapshot name, or NULL
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* @errp: location to store error
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*
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* If both @snapshot_id and @name are specified, delete the first one with
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* id @snapshot_id and name @name.
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* If only @snapshot_id is specified, delete the first one with id
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* @snapshot_id.
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* If only @name is specified, delete the first one with name @name.
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* if none is specified, return -EINVAL.
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*
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* Returns: 0 on success, -errno on failure. If @bs is not inserted, return
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* -ENOMEDIUM. If @snapshot_id and @name are both NULL, return -EINVAL. If @bs
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* does not support internal snapshot deletion, return -ENOTSUP. If @bs does
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* not support parameter @snapshot_id or @name, or one of them is not correctly
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* specified, return -EINVAL. If @bs can't find one matching @id and @name,
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* return -ENOENT. If @errp != NULL, it will always be filled with error
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* message on failure.
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*/
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int bdrv_snapshot_delete(BlockDriverState *bs,
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const char *snapshot_id,
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const char *name,
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Error **errp)
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{
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BlockDriver *drv = bs->drv;
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if (!drv) {
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error_set(errp, QERR_DEVICE_HAS_NO_MEDIUM, bdrv_get_device_name(bs));
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return -ENOMEDIUM;
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}
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if (!snapshot_id && !name) {
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error_setg(errp, "snapshot_id and name are both NULL");
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return -EINVAL;
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}
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/* drain all pending i/o before deleting snapshot */
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bdrv_drain_all();
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if (drv->bdrv_snapshot_delete) {
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return drv->bdrv_snapshot_delete(bs, snapshot_id, name, errp);
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}
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if (bs->file) {
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return bdrv_snapshot_delete(bs->file, snapshot_id, name, errp);
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}
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error_setg(errp, "Block format '%s' used by device '%s' "
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"does not support internal snapshot deletion",
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drv->format_name, bdrv_get_device_name(bs));
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return -ENOTSUP;
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}
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void bdrv_snapshot_delete_by_id_or_name(BlockDriverState *bs,
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const char *id_or_name,
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Error **errp)
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{
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int ret;
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Error *local_err = NULL;
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ret = bdrv_snapshot_delete(bs, id_or_name, NULL, &local_err);
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if (ret == -ENOENT || ret == -EINVAL) {
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error_free(local_err);
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local_err = NULL;
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ret = bdrv_snapshot_delete(bs, NULL, id_or_name, &local_err);
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}
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if (ret < 0) {
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error_propagate(errp, local_err);
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}
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}
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int bdrv_snapshot_list(BlockDriverState *bs,
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QEMUSnapshotInfo **psn_info)
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{
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BlockDriver *drv = bs->drv;
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if (!drv) {
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return -ENOMEDIUM;
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}
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if (drv->bdrv_snapshot_list) {
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return drv->bdrv_snapshot_list(bs, psn_info);
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}
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if (bs->file) {
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return bdrv_snapshot_list(bs->file, psn_info);
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}
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return -ENOTSUP;
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}
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/**
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* Temporarily load an internal snapshot by @snapshot_id and @name.
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* @bs: block device used in the operation
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* @snapshot_id: unique snapshot ID, or NULL
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* @name: snapshot name, or NULL
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* @errp: location to store error
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*
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* If both @snapshot_id and @name are specified, load the first one with
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* id @snapshot_id and name @name.
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* If only @snapshot_id is specified, load the first one with id
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* @snapshot_id.
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* If only @name is specified, load the first one with name @name.
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* if none is specified, return -EINVAL.
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*
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* Returns: 0 on success, -errno on fail. If @bs is not inserted, return
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* -ENOMEDIUM. If @bs is not readonly, return -EINVAL. If @bs did not support
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* internal snapshot, return -ENOTSUP. If qemu can't find a matching @id and
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* @name, return -ENOENT. If @errp != NULL, it will always be filled on
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* failure.
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*/
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int bdrv_snapshot_load_tmp(BlockDriverState *bs,
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const char *snapshot_id,
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const char *name,
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Error **errp)
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{
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BlockDriver *drv = bs->drv;
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if (!drv) {
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error_set(errp, QERR_DEVICE_HAS_NO_MEDIUM, bdrv_get_device_name(bs));
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return -ENOMEDIUM;
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}
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if (!snapshot_id && !name) {
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error_setg(errp, "snapshot_id and name are both NULL");
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return -EINVAL;
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}
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if (!bs->read_only) {
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error_setg(errp, "Device is not readonly");
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return -EINVAL;
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}
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if (drv->bdrv_snapshot_load_tmp) {
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return drv->bdrv_snapshot_load_tmp(bs, snapshot_id, name, errp);
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}
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error_setg(errp, "Block format '%s' used by device '%s' "
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"does not support temporarily loading internal snapshots",
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drv->format_name, bdrv_get_device_name(bs));
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return -ENOTSUP;
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}
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int bdrv_snapshot_load_tmp_by_id_or_name(BlockDriverState *bs,
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const char *id_or_name,
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Error **errp)
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{
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int ret;
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Error *local_err = NULL;
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ret = bdrv_snapshot_load_tmp(bs, id_or_name, NULL, &local_err);
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if (ret == -ENOENT || ret == -EINVAL) {
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error_free(local_err);
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local_err = NULL;
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ret = bdrv_snapshot_load_tmp(bs, NULL, id_or_name, &local_err);
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}
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if (local_err) {
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error_propagate(errp, local_err);
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}
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return ret;
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}
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