diff options
Diffstat (limited to 'qemu/block/snapshot.c')
| -rw-r--r-- | qemu/block/snapshot.c | 358 |
1 files changed, 358 insertions, 0 deletions
diff --git a/qemu/block/snapshot.c b/qemu/block/snapshot.c new file mode 100644 index 000000000..49e143e99 --- /dev/null +++ b/qemu/block/snapshot.c @@ -0,0 +1,358 @@ +/* + * Block layer snapshot related functions + * + * Copyright (c) 2003-2008 Fabrice Bellard + * + * Permission is hereby granted, free of charge, to any person obtaining a copy + * of this software and associated documentation files (the "Software"), to deal + * in the Software without restriction, including without limitation the rights + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell + * copies of the Software, and to permit persons to whom the Software is + * furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice shall be included in + * all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN + * THE SOFTWARE. + */ + +#include "block/snapshot.h" +#include "block/block_int.h" +#include "qapi/qmp/qerror.h" + +QemuOptsList internal_snapshot_opts = { + .name = "snapshot", + .head = QTAILQ_HEAD_INITIALIZER(internal_snapshot_opts.head), + .desc = { + { + .name = SNAPSHOT_OPT_ID, + .type = QEMU_OPT_STRING, + .help = "snapshot id" + },{ + .name = SNAPSHOT_OPT_NAME, + .type = QEMU_OPT_STRING, + .help = "snapshot name" + },{ + /* end of list */ + } + }, +}; + +int bdrv_snapshot_find(BlockDriverState *bs, QEMUSnapshotInfo *sn_info, + const char *name) +{ + QEMUSnapshotInfo *sn_tab, *sn; + int nb_sns, i, ret; + + ret = -ENOENT; + nb_sns = bdrv_snapshot_list(bs, &sn_tab); + if (nb_sns < 0) { + return ret; + } + for (i = 0; i < nb_sns; i++) { + sn = &sn_tab[i]; + if (!strcmp(sn->id_str, name) || !strcmp(sn->name, name)) { + *sn_info = *sn; + ret = 0; + break; + } + } + g_free(sn_tab); + return ret; +} + +/** + * Look up an internal snapshot by @id and @name. + * @bs: block device to search + * @id: unique snapshot ID, or NULL + * @name: snapshot name, or NULL + * @sn_info: location to store information on the snapshot found + * @errp: location to store error, will be set only for exception + * + * This function will traverse snapshot list in @bs to search the matching + * one, @id and @name are the matching condition: + * If both @id and @name are specified, find the first one with id @id and + * name @name. + * If only @id is specified, find the first one with id @id. + * If only @name is specified, find the first one with name @name. + * if none is specified, abort(). + * + * Returns: true when a snapshot is found and @sn_info will be filled, false + * when error or not found. If all operation succeed but no matching one is + * found, @errp will NOT be set. + */ +bool bdrv_snapshot_find_by_id_and_name(BlockDriverState *bs, + const char *id, + const char *name, + QEMUSnapshotInfo *sn_info, + Error **errp) +{ + QEMUSnapshotInfo *sn_tab, *sn; + int nb_sns, i; + bool ret = false; + + assert(id || name); + + nb_sns = bdrv_snapshot_list(bs, &sn_tab); + if (nb_sns < 0) { + error_setg_errno(errp, -nb_sns, "Failed to get a snapshot list"); + return false; + } else if (nb_sns == 0) { + return false; + } + + if (id && name) { + for (i = 0; i < nb_sns; i++) { + sn = &sn_tab[i]; + if (!strcmp(sn->id_str, id) && !strcmp(sn->name, name)) { + *sn_info = *sn; + ret = true; + break; + } + } + } else if (id) { + for (i = 0; i < nb_sns; i++) { + sn = &sn_tab[i]; + if (!strcmp(sn->id_str, id)) { + *sn_info = *sn; + ret = true; + break; + } + } + } else if (name) { + for (i = 0; i < nb_sns; i++) { + sn = &sn_tab[i]; + if (!strcmp(sn->name, name)) { + *sn_info = *sn; + ret = true; + break; + } + } + } + + g_free(sn_tab); + return ret; +} + +int bdrv_can_snapshot(BlockDriverState *bs) +{ + BlockDriver *drv = bs->drv; + if (!drv || !bdrv_is_inserted(bs) || bdrv_is_read_only(bs)) { + return 0; + } + + if (!drv->bdrv_snapshot_create) { + if (bs->file != NULL) { + return bdrv_can_snapshot(bs->file); + } + return 0; + } + + return 1; +} + +int bdrv_snapshot_create(BlockDriverState *bs, + QEMUSnapshotInfo *sn_info) +{ + BlockDriver *drv = bs->drv; + 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, sn_info); + } + return -ENOTSUP; +} + +int bdrv_snapshot_goto(BlockDriverState *bs, + const char *snapshot_id) +{ + BlockDriver *drv = bs->drv; + int ret, open_ret; + + if (!drv) { + return -ENOMEDIUM; + } + if (drv->bdrv_snapshot_goto) { + return drv->bdrv_snapshot_goto(bs, snapshot_id); + } + + if (bs->file) { + drv->bdrv_close(bs); + ret = bdrv_snapshot_goto(bs->file, snapshot_id); + open_ret = drv->bdrv_open(bs, NULL, bs->open_flags, NULL); + if (open_ret < 0) { + bdrv_unref(bs->file); + bs->drv = NULL; + return open_ret; + } + return ret; + } + + return -ENOTSUP; +} + +/** + * Delete an internal snapshot by @snapshot_id and @name. + * @bs: block device used in the operation + * @snapshot_id: unique snapshot ID, or NULL + * @name: snapshot name, or NULL + * @errp: location to store error + * + * If both @snapshot_id and @name are specified, delete the first one with + * id @snapshot_id and name @name. + * If only @snapshot_id is specified, delete the first one with id + * @snapshot_id. + * If only @name is specified, delete the first one with name @name. + * if none is specified, return -EINVAL. + * + * Returns: 0 on success, -errno on failure. If @bs is not inserted, return + * -ENOMEDIUM. If @snapshot_id and @name are both NULL, return -EINVAL. If @bs + * does not support internal snapshot deletion, return -ENOTSUP. If @bs does + * not support parameter @snapshot_id or @name, or one of them is not correctly + * specified, return -EINVAL. If @bs can't find one matching @id and @name, + * return -ENOENT. If @errp != NULL, it will always be filled with error + * message on failure. + */ +int bdrv_snapshot_delete(BlockDriverState *bs, + const char *snapshot_id, + const char *name, + Error **errp) +{ + BlockDriver *drv = bs->drv; + if (!drv) { + error_setg(errp, QERR_DEVICE_HAS_NO_MEDIUM, bdrv_get_device_name(bs)); + return -ENOMEDIUM; + } + if (!snapshot_id && !name) { + error_setg(errp, "snapshot_id and name are both NULL"); + return -EINVAL; + } + + /* drain all pending i/o before deleting snapshot */ + bdrv_drain(bs); + + if (drv->bdrv_snapshot_delete) { + return drv->bdrv_snapshot_delete(bs, snapshot_id, name, errp); + } + if (bs->file) { + return bdrv_snapshot_delete(bs->file, snapshot_id, name, errp); + } + error_setg(errp, "Block format '%s' used by device '%s' " + "does not support internal snapshot deletion", + drv->format_name, bdrv_get_device_name(bs)); + return -ENOTSUP; +} + +void 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); + } +} + +int bdrv_snapshot_list(BlockDriverState *bs, + QEMUSnapshotInfo **psn_info) +{ + BlockDriver *drv = bs->drv; + 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, psn_info); + } + return -ENOTSUP; +} + +/** + * Temporarily load an internal snapshot by @snapshot_id and @name. + * @bs: block device used in the operation + * @snapshot_id: unique snapshot ID, or NULL + * @name: snapshot name, or NULL + * @errp: location to store error + * + * If both @snapshot_id and @name are specified, load the first one with + * id @snapshot_id and name @name. + * If only @snapshot_id is specified, load the first one with id + * @snapshot_id. + * If only @name is specified, load the first one with name @name. + * if none is specified, return -EINVAL. + * + * Returns: 0 on success, -errno on fail. If @bs is not inserted, return + * -ENOMEDIUM. If @bs is not readonly, return -EINVAL. If @bs did not support + * internal snapshot, return -ENOTSUP. If qemu can't find a matching @id and + * @name, return -ENOENT. If @errp != NULL, it will always be filled on + * failure. + */ +int bdrv_snapshot_load_tmp(BlockDriverState *bs, + const char *snapshot_id, + const char *name, + Error **errp) +{ + BlockDriver *drv = bs->drv; + + if (!drv) { + error_setg(errp, QERR_DEVICE_HAS_NO_MEDIUM, bdrv_get_device_name(bs)); + return -ENOMEDIUM; + } + if (!snapshot_id && !name) { + error_setg(errp, "snapshot_id and name are both NULL"); + return -EINVAL; + } + if (!bs->read_only) { + error_setg(errp, "Device is not readonly"); + return -EINVAL; + } + if (drv->bdrv_snapshot_load_tmp) { + return drv->bdrv_snapshot_load_tmp(bs, snapshot_id, name, errp); + } + error_setg(errp, "Block format '%s' used by device '%s' " + "does not support temporarily loading internal snapshots", + drv->format_name, bdrv_get_device_name(bs)); + return -ENOTSUP; +} + +int bdrv_snapshot_load_tmp_by_id_or_name(BlockDriverState *bs, + const char *id_or_name, + Error **errp) +{ + int ret; + Error *local_err = NULL; + + ret = bdrv_snapshot_load_tmp(bs, id_or_name, NULL, &local_err); + if (ret == -ENOENT || ret == -EINVAL) { + error_free(local_err); + local_err = NULL; + ret = bdrv_snapshot_load_tmp(bs, NULL, id_or_name, &local_err); + } + + if (local_err) { + error_propagate(errp, local_err); + } + + return ret; +} |