| /* |
| * 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 "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" |
| |
| 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->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->bs); |
| } |
| 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->bs, sn_info); |
| } |
| return -ENOTSUP; |
| } |
| |
| int bdrv_snapshot_goto(BlockDriverState *bs, |
| const char *snapshot_id, |
| Error **errp) |
| { |
| BlockDriver *drv = bs->drv; |
| 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) { |
| 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); |
| QDict *file_options; |
| Error *local_err = NULL; |
| |
| file = bs->file->bs; |
| /* Prevent it from getting deleted when detached from bs */ |
| bdrv_ref(file); |
| |
| qdict_extract_subqdict(options, &file_options, "file."); |
| qobject_unref(file_options); |
| qdict_put_str(options, "file", bdrv_get_node_name(file)); |
| |
| if (drv->bdrv_close) { |
| drv->bdrv_close(bs); |
| } |
| bdrv_unref_child(bs, bs->file); |
| bs->file = NULL; |
| |
| ret = bdrv_snapshot_goto(file, 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); |
| bs->drv = NULL; |
| /* 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); |
| return ret; |
| } |
| |
| error_setg(errp, "Block driver does not support snapshots"); |
| 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; |
| int ret; |
| |
| 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_drained_begin(bs); |
| |
| 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 { |
| error_setg(errp, "Block format '%s' used by device '%s' " |
| "does not support internal snapshot deletion", |
| drv->format_name, bdrv_get_device_name(bs)); |
| ret = -ENOTSUP; |
| } |
| |
| bdrv_drained_end(bs); |
| return ret; |
| } |
| |
| 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->bs, 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); |
| } |
| |
| error_propagate(errp, local_err); |
| |
| return ret; |
| } |
| |
| |
| /* 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 ok = true; |
| BlockDriverState *bs; |
| BdrvNextIterator it; |
| |
| for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) { |
| AioContext *ctx = bdrv_get_aio_context(bs); |
| |
| aio_context_acquire(ctx); |
| if (bdrv_is_inserted(bs) && !bdrv_is_read_only(bs)) { |
| ok = bdrv_can_snapshot(bs); |
| } |
| aio_context_release(ctx); |
| if (!ok) { |
| bdrv_next_cleanup(&it); |
| goto fail; |
| } |
| } |
| |
| fail: |
| *first_bad_bs = bs; |
| return ok; |
| } |
| |
| int bdrv_all_delete_snapshot(const char *name, BlockDriverState **first_bad_bs, |
| Error **err) |
| { |
| int ret = 0; |
| BlockDriverState *bs; |
| BdrvNextIterator it; |
| QEMUSnapshotInfo sn1, *snapshot = &sn1; |
| |
| for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) { |
| AioContext *ctx = bdrv_get_aio_context(bs); |
| |
| aio_context_acquire(ctx); |
| if (bdrv_can_snapshot(bs) && |
| bdrv_snapshot_find(bs, snapshot, name) >= 0) { |
| ret = bdrv_snapshot_delete(bs, snapshot->id_str, |
| snapshot->name, err); |
| } |
| aio_context_release(ctx); |
| if (ret < 0) { |
| bdrv_next_cleanup(&it); |
| goto fail; |
| } |
| } |
| |
| fail: |
| *first_bad_bs = bs; |
| return ret; |
| } |
| |
| |
| int bdrv_all_goto_snapshot(const char *name, BlockDriverState **first_bad_bs, |
| Error **errp) |
| { |
| int ret = 0; |
| BlockDriverState *bs; |
| BdrvNextIterator it; |
| |
| for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) { |
| AioContext *ctx = bdrv_get_aio_context(bs); |
| |
| aio_context_acquire(ctx); |
| if (bdrv_can_snapshot(bs)) { |
| ret = bdrv_snapshot_goto(bs, name, errp); |
| } |
| aio_context_release(ctx); |
| if (ret < 0) { |
| bdrv_next_cleanup(&it); |
| goto fail; |
| } |
| } |
| |
| fail: |
| *first_bad_bs = bs; |
| return ret; |
| } |
| |
| int bdrv_all_find_snapshot(const char *name, BlockDriverState **first_bad_bs) |
| { |
| QEMUSnapshotInfo sn; |
| int err = 0; |
| BlockDriverState *bs; |
| BdrvNextIterator it; |
| |
| for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) { |
| AioContext *ctx = bdrv_get_aio_context(bs); |
| |
| aio_context_acquire(ctx); |
| if (bdrv_can_snapshot(bs)) { |
| err = bdrv_snapshot_find(bs, &sn, name); |
| } |
| aio_context_release(ctx); |
| if (err < 0) { |
| bdrv_next_cleanup(&it); |
| goto fail; |
| } |
| } |
| |
| fail: |
| *first_bad_bs = bs; |
| return err; |
| } |
| |
| int bdrv_all_create_snapshot(QEMUSnapshotInfo *sn, |
| BlockDriverState *vm_state_bs, |
| uint64_t vm_state_size, |
| BlockDriverState **first_bad_bs) |
| { |
| int err = 0; |
| BlockDriverState *bs; |
| BdrvNextIterator it; |
| |
| for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) { |
| AioContext *ctx = bdrv_get_aio_context(bs); |
| |
| 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)) { |
| sn->vm_state_size = 0; |
| err = bdrv_snapshot_create(bs, sn); |
| } |
| aio_context_release(ctx); |
| if (err < 0) { |
| bdrv_next_cleanup(&it); |
| goto fail; |
| } |
| } |
| |
| fail: |
| *first_bad_bs = bs; |
| return err; |
| } |
| |
| BlockDriverState *bdrv_all_find_vmstate_bs(void) |
| { |
| BlockDriverState *bs; |
| BdrvNextIterator it; |
| |
| for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) { |
| AioContext *ctx = bdrv_get_aio_context(bs); |
| bool found; |
| |
| aio_context_acquire(ctx); |
| found = bdrv_can_snapshot(bs); |
| aio_context_release(ctx); |
| |
| if (found) { |
| bdrv_next_cleanup(&it); |
| break; |
| } |
| } |
| return bs; |
| } |