[qemu.git] / block / snapshot.c

/*
 * 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 "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->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)
{
    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->bs, snapshot_id);
        open_ret = drv->bdrv_open(bs, NULL, bs->open_flags, NULL);
        if (open_ret < 0) {
            bdrv_unref(bs->file->bs);
            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;
    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_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;
    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);
    }

    if (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 = NULL;

    while (ok && (bs = bdrv_next(bs))) {
        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);
    }

    *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 = NULL;
    QEMUSnapshotInfo sn1, *snapshot = &sn1;

    while (ret == 0 && (bs = bdrv_next(bs))) {
        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_by_id_or_name(bs, name, err);
        }
        aio_context_release(ctx);
    }

    *first_bad_bs = bs;
    return ret;
}


int bdrv_all_goto_snapshot(const char *name, BlockDriverState **first_bad_bs)
{
    int err = 0;
    BlockDriverState *bs = NULL;

    while (err == 0 && (bs = bdrv_next(bs))) {
        AioContext *ctx = bdrv_get_aio_context(bs);

        aio_context_acquire(ctx);
        if (bdrv_can_snapshot(bs)) {
            err = bdrv_snapshot_goto(bs, name);
        }
        aio_context_release(ctx);
    }

    *first_bad_bs = bs;
    return err;
}

int bdrv_all_find_snapshot(const char *name, BlockDriverState **first_bad_bs)
{
    QEMUSnapshotInfo sn;
    int err = 0;
    BlockDriverState *bs = NULL;

    while (err == 0 && (bs = bdrv_next(bs))) {
        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);
    }

    *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 = NULL;

    while (err == 0 && (bs = bdrv_next(bs))) {
        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);
    }

    *first_bad_bs = bs;
    return err;
}

BlockDriverState *bdrv_all_find_vmstate_bs(void)
{
    bool not_found = true;
    BlockDriverState *bs = NULL;

    while (not_found && (bs = bdrv_next(bs))) {
        AioContext *ctx = bdrv_get_aio_context(bs);

        aio_context_acquire(ctx);
        not_found = !bdrv_can_snapshot(bs);
        aio_context_release(ctx);
    }
    return bs;
}
Commit	Line	Data
de08c606 WX	1	/*
	2	* Block layer snapshot related functions
	3	*
	4	* Copyright (c) 2003-2008 Fabrice Bellard
	5	*
	6	* Permission is hereby granted, free of charge, to any person obtaining a copy
	7	* of this software and associated documentation files (the "Software"), to deal
	8	* in the Software without restriction, including without limitation the rights
	9	* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
	10	* copies of the Software, and to permit persons to whom the Software is
	11	* furnished to do so, subject to the following conditions:
	12	*
	13	* The above copyright notice and this permission notice shall be included in
	14	* all copies or substantial portions of the Software.
	15	*
	16	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
	17	* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
	18	* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
	19	* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
	20	* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
	21	* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
	22	* THE SOFTWARE.
	23	*/
	24
80c71a24	25	#include "qemu/osdep.h"
de08c606 WX	26	#include "block/snapshot.h"
de08c606 WX	27	#include "block/block_int.h"
cc7a8ea7	28	#include "qapi/qmp/qerror.h"
de08c606	29
8c116b0e WX	30	QemuOptsList internal_snapshot_opts = {
	31	.name = "snapshot",
	32	.head = QTAILQ_HEAD_INITIALIZER(internal_snapshot_opts.head),
	33	.desc = {
	34	{
	35	.name = SNAPSHOT_OPT_ID,
	36	.type = QEMU_OPT_STRING,
	37	.help = "snapshot id"
	38	},{
	39	.name = SNAPSHOT_OPT_NAME,
	40	.type = QEMU_OPT_STRING,
	41	.help = "snapshot name"
	42	},{
	43	/* end of list */
	44	}
	45	},
	46	};
	47
de08c606 WX	48	int bdrv_snapshot_find(BlockDriverState bs, QEMUSnapshotInfo sn_info,
	49	const char *name)
	50	{
	51	QEMUSnapshotInfo sn_tab, sn;
	52	int nb_sns, i, ret;
	53
	54	ret = -ENOENT;
	55	nb_sns = bdrv_snapshot_list(bs, &sn_tab);
	56	if (nb_sns < 0) {
	57	return ret;
	58	}
	59	for (i = 0; i < nb_sns; i++) {
	60	sn = &sn_tab[i];
	61	if (!strcmp(sn->id_str, name) \|\| !strcmp(sn->name, name)) {
	62	sn_info = sn;
	63	ret = 0;
	64	break;
	65	}
	66	}
	67	g_free(sn_tab);
	68	return ret;
	69	}
	70
2ea1dd75 WX	71	/**
	72	* Look up an internal snapshot by @id and @name.
	73	* @bs: block device to search
	74	* @id: unique snapshot ID, or NULL
	75	* @name: snapshot name, or NULL
	76	* @sn_info: location to store information on the snapshot found
	77	* @errp: location to store error, will be set only for exception
	78	*
	79	* This function will traverse snapshot list in @bs to search the matching
	80	* one, @id and @name are the matching condition:
	81	* If both @id and @name are specified, find the first one with id @id and
	82	* name @name.
	83	* If only @id is specified, find the first one with id @id.
	84	* If only @name is specified, find the first one with name @name.
	85	* if none is specified, abort().
	86	*
	87	* Returns: true when a snapshot is found and @sn_info will be filled, false
	88	* when error or not found. If all operation succeed but no matching one is
	89	* found, @errp will NOT be set.
	90	*/
	91	bool bdrv_snapshot_find_by_id_and_name(BlockDriverState *bs,
	92	const char *id,
	93	const char *name,
	94	QEMUSnapshotInfo *sn_info,
	95	Error **errp)
	96	{
	97	QEMUSnapshotInfo sn_tab, sn;
	98	int nb_sns, i;
	99	bool ret = false;
	100
	101	assert(id \|\| name);
	102
	103	nb_sns = bdrv_snapshot_list(bs, &sn_tab);
	104	if (nb_sns < 0) {
	105	error_setg_errno(errp, -nb_sns, "Failed to get a snapshot list");
	106	return false;
	107	} else if (nb_sns == 0) {
	108	return false;
	109	}
	110
	111	if (id && name) {
	112	for (i = 0; i < nb_sns; i++) {
	113	sn = &sn_tab[i];
	114	if (!strcmp(sn->id_str, id) && !strcmp(sn->name, name)) {
	115	sn_info = sn;
	116	ret = true;
	117	break;
	118	}
	119	}
	120	} else if (id) {
	121	for (i = 0; i < nb_sns; i++) {
	122	sn = &sn_tab[i];
	123	if (!strcmp(sn->id_str, id)) {
	124	sn_info = sn;
	125	ret = true;
	126	break;
	127	}
	128	}
	129	} else if (name) {
	130	for (i = 0; i < nb_sns; i++) {
	131	sn = &sn_tab[i];
	132	if (!strcmp(sn->name, name)) {
	133	sn_info = sn;
	134	ret = true;
135	break;
136	}
137	}
138	}
139
140	g_free(sn_tab);
141	return ret;
142	}
143
de08c606 WX	144	int bdrv_can_snapshot(BlockDriverState *bs)
	145	{
	146	BlockDriver *drv = bs->drv;
	147	if (!drv \|\| !bdrv_is_inserted(bs) \|\| bdrv_is_read_only(bs)) {
	148	return 0;
	149	}
	150
	151	if (!drv->bdrv_snapshot_create) {
	152	if (bs->file != NULL) {
9a4f4c31	153	return bdrv_can_snapshot(bs->file->bs);
de08c606 WX	154	}
	155	return 0;
	156	}
	157
	158	return 1;
	159	}
	160
	161	int bdrv_snapshot_create(BlockDriverState *bs,
	162	QEMUSnapshotInfo *sn_info)
	163	{
	164	BlockDriver *drv = bs->drv;
	165	if (!drv) {
	166	return -ENOMEDIUM;
	167	}
	168	if (drv->bdrv_snapshot_create) {
	169	return drv->bdrv_snapshot_create(bs, sn_info);
	170	}
	171	if (bs->file) {
9a4f4c31	172	return bdrv_snapshot_create(bs->file->bs, sn_info);
de08c606 WX	173	}
	174	return -ENOTSUP;
	175	}
	176
	177	int bdrv_snapshot_goto(BlockDriverState *bs,
	178	const char *snapshot_id)
	179	{
	180	BlockDriver *drv = bs->drv;
	181	int ret, open_ret;
	182
	183	if (!drv) {
	184	return -ENOMEDIUM;
	185	}
	186	if (drv->bdrv_snapshot_goto) {
	187	return drv->bdrv_snapshot_goto(bs, snapshot_id);
	188	}
	189
	190	if (bs->file) {
	191	drv->bdrv_close(bs);
9a4f4c31	192	ret = bdrv_snapshot_goto(bs->file->bs, snapshot_id);
015a1036	193	open_ret = drv->bdrv_open(bs, NULL, bs->open_flags, NULL);
de08c606	194	if (open_ret < 0) {
9a4f4c31	195	bdrv_unref(bs->file->bs);
de08c606 WX	196	bs->drv = NULL;
	197	return open_ret;
	198	}
	199	return ret;
	200	}
	201
	202	return -ENOTSUP;
	203	}
	204
a89d89d3 WX	205	/**
	206	* Delete an internal snapshot by @snapshot_id and @name.
	207	* @bs: block device used in the operation
	208	* @snapshot_id: unique snapshot ID, or NULL
	209	* @name: snapshot name, or NULL
	210	* @errp: location to store error
	211	*
	212	* If both @snapshot_id and @name are specified, delete the first one with
	213	* id @snapshot_id and name @name.
	214	* If only @snapshot_id is specified, delete the first one with id
	215	* @snapshot_id.
	216	* If only @name is specified, delete the first one with name @name.
7b4c4781	217	* if none is specified, return -EINVAL.
a89d89d3 WX	218	*
	219	* Returns: 0 on success, -errno on failure. If @bs is not inserted, return
	220	* -ENOMEDIUM. If @snapshot_id and @name are both NULL, return -EINVAL. If @bs
	221	* does not support internal snapshot deletion, return -ENOTSUP. If @bs does
	222	* not support parameter @snapshot_id or @name, or one of them is not correctly
	223	* specified, return -EINVAL. If @bs can't find one matching @id and @name,
	224	* return -ENOENT. If @errp != NULL, it will always be filled with error
	225	* message on failure.
	226	*/
	227	int bdrv_snapshot_delete(BlockDriverState *bs,
	228	const char *snapshot_id,
	229	const char *name,
	230	Error **errp)
de08c606 WX	231	{
de08c606 WX	232	BlockDriver *drv = bs->drv;
27a7649a PB	233	int ret;
27a7649a PB	234
de08c606	235	if (!drv) {
c6bd8c70	236	error_setg(errp, QERR_DEVICE_HAS_NO_MEDIUM, bdrv_get_device_name(bs));
de08c606 WX	237	return -ENOMEDIUM;
de08c606 WX	238	}
a89d89d3 WX	239	if (!snapshot_id && !name) {
	240	error_setg(errp, "snapshot_id and name are both NULL");
	241	return -EINVAL;
	242	}
3432a192 ZH	243
3432a192 ZH	244	/* drain all pending i/o before deleting snapshot */
27a7649a	245	bdrv_drained_begin(bs);
3432a192	246
de08c606	247	if (drv->bdrv_snapshot_delete) {
27a7649a PB	248	ret = drv->bdrv_snapshot_delete(bs, snapshot_id, name, errp);
	249	} else if (bs->file) {
	250	ret = bdrv_snapshot_delete(bs->file->bs, snapshot_id, name, errp);
	251	} else {
	252	error_setg(errp, "Block format '%s' used by device '%s' "
	253	"does not support internal snapshot deletion",
	254	drv->format_name, bdrv_get_device_name(bs));
	255	ret = -ENOTSUP;
de08c606	256	}
27a7649a PB	257
	258	bdrv_drained_end(bs);
	259	return ret;
de08c606 WX	260	}
de08c606 WX	261
25af925f DL	262	int bdrv_snapshot_delete_by_id_or_name(BlockDriverState *bs,
	263	const char *id_or_name,
	264	Error **errp)
a89d89d3 WX	265	{
	266	int ret;
	267	Error *local_err = NULL;
	268
	269	ret = bdrv_snapshot_delete(bs, id_or_name, NULL, &local_err);
	270	if (ret == -ENOENT \|\| ret == -EINVAL) {
	271	error_free(local_err);
	272	local_err = NULL;
	273	ret = bdrv_snapshot_delete(bs, NULL, id_or_name, &local_err);
	274	}
	275
	276	if (ret < 0) {
	277	error_propagate(errp, local_err);
	278	}
25af925f	279	return ret;
a89d89d3 WX	280	}
a89d89d3 WX	281
de08c606 WX	282	int bdrv_snapshot_list(BlockDriverState *bs,
	283	QEMUSnapshotInfo **psn_info)
	284	{
	285	BlockDriver *drv = bs->drv;
	286	if (!drv) {
	287	return -ENOMEDIUM;
	288	}
	289	if (drv->bdrv_snapshot_list) {
	290	return drv->bdrv_snapshot_list(bs, psn_info);
	291	}
	292	if (bs->file) {
9a4f4c31	293	return bdrv_snapshot_list(bs->file->bs, psn_info);
de08c606 WX	294	}
	295	return -ENOTSUP;
	296	}
	297
7b4c4781 WX	298	/**
	299	* Temporarily load an internal snapshot by @snapshot_id and @name.
	300	* @bs: block device used in the operation
	301	* @snapshot_id: unique snapshot ID, or NULL
	302	* @name: snapshot name, or NULL
	303	* @errp: location to store error
	304	*
	305	* If both @snapshot_id and @name are specified, load the first one with
	306	* id @snapshot_id and name @name.
	307	* If only @snapshot_id is specified, load the first one with id
	308	* @snapshot_id.
	309	* If only @name is specified, load the first one with name @name.
	310	* if none is specified, return -EINVAL.
	311	*
	312	* Returns: 0 on success, -errno on fail. If @bs is not inserted, return
	313	* -ENOMEDIUM. If @bs is not readonly, return -EINVAL. If @bs did not support
	314	* internal snapshot, return -ENOTSUP. If qemu can't find a matching @id and
	315	* @name, return -ENOENT. If @errp != NULL, it will always be filled on
	316	* failure.
	317	*/
de08c606	318	int bdrv_snapshot_load_tmp(BlockDriverState *bs,
7b4c4781 WX	319	const char *snapshot_id,
	320	const char *name,
	321	Error **errp)
de08c606 WX	322	{
de08c606 WX	323	BlockDriver *drv = bs->drv;
7b4c4781	324
de08c606	325	if (!drv) {
c6bd8c70	326	error_setg(errp, QERR_DEVICE_HAS_NO_MEDIUM, bdrv_get_device_name(bs));
de08c606 WX	327	return -ENOMEDIUM;
de08c606 WX	328	}
7b4c4781 WX	329	if (!snapshot_id && !name) {
	330	error_setg(errp, "snapshot_id and name are both NULL");
	331	return -EINVAL;
	332	}
de08c606	333	if (!bs->read_only) {
7b4c4781	334	error_setg(errp, "Device is not readonly");
de08c606 WX	335	return -EINVAL;
	336	}
	337	if (drv->bdrv_snapshot_load_tmp) {
7b4c4781	338	return drv->bdrv_snapshot_load_tmp(bs, snapshot_id, name, errp);
de08c606	339	}
81e5f78a AG	340	error_setg(errp, "Block format '%s' used by device '%s' "
	341	"does not support temporarily loading internal snapshots",
	342	drv->format_name, bdrv_get_device_name(bs));
de08c606 WX	343	return -ENOTSUP;
de08c606 WX	344	}
7b4c4781 WX	345
	346	int bdrv_snapshot_load_tmp_by_id_or_name(BlockDriverState *bs,
	347	const char *id_or_name,
	348	Error **errp)
	349	{
	350	int ret;
	351	Error *local_err = NULL;
	352
	353	ret = bdrv_snapshot_load_tmp(bs, id_or_name, NULL, &local_err);
	354	if (ret == -ENOENT \|\| ret == -EINVAL) {
	355	error_free(local_err);
	356	local_err = NULL;
	357	ret = bdrv_snapshot_load_tmp(bs, NULL, id_or_name, &local_err);
	358	}
	359
84d18f06	360	if (local_err) {
7b4c4781 WX	361	error_propagate(errp, local_err);
	362	}
	363
	364	return ret;
	365	}
e9ff957a DL	366
	367
	368	/* Group operations. All block drivers are involved.
	369	* These functions will properly handle dataplane (take aio_context_acquire
	370	* when appropriate for appropriate block drivers) */
	371
	372	bool bdrv_all_can_snapshot(BlockDriverState **first_bad_bs)
	373	{
	374	bool ok = true;
	375	BlockDriverState *bs = NULL;
	376
	377	while (ok && (bs = bdrv_next(bs))) {
	378	AioContext *ctx = bdrv_get_aio_context(bs);
	379
	380	aio_context_acquire(ctx);
	381	if (bdrv_is_inserted(bs) && !bdrv_is_read_only(bs)) {
	382	ok = bdrv_can_snapshot(bs);
	383	}
	384	aio_context_release(ctx);
	385	}
	386
	387	*first_bad_bs = bs;
	388	return ok;
	389	}
9b00ea37 DL	390
	391	int bdrv_all_delete_snapshot(const char name, BlockDriverState *first_bad_bs,
	392	Error **err)
	393	{
	394	int ret = 0;
	395	BlockDriverState *bs = NULL;
	396	QEMUSnapshotInfo sn1, *snapshot = &sn1;
	397
	398	while (ret == 0 && (bs = bdrv_next(bs))) {
	399	AioContext *ctx = bdrv_get_aio_context(bs);
	400
	401	aio_context_acquire(ctx);
	402	if (bdrv_can_snapshot(bs) &&
	403	bdrv_snapshot_find(bs, snapshot, name) >= 0) {
	404	ret = bdrv_snapshot_delete_by_id_or_name(bs, name, err);
	405	}
	406	aio_context_release(ctx);
	407	}
	408
	409	*first_bad_bs = bs;
	410	return ret;
	411	}
4c1cdbaa DL	412
	413
	414	int bdrv_all_goto_snapshot(const char name, BlockDriverState *first_bad_bs)
	415	{
	416	int err = 0;
	417	BlockDriverState *bs = NULL;
	418
	419	while (err == 0 && (bs = bdrv_next(bs))) {
	420	AioContext *ctx = bdrv_get_aio_context(bs);
	421
	422	aio_context_acquire(ctx);
	423	if (bdrv_can_snapshot(bs)) {
	424	err = bdrv_snapshot_goto(bs, name);
	425	}
	426	aio_context_release(ctx);
	427	}
	428
	429	*first_bad_bs = bs;
	430	return err;
	431	}
723ccda1 DL	432
	433	int bdrv_all_find_snapshot(const char name, BlockDriverState *first_bad_bs)
	434	{
	435	QEMUSnapshotInfo sn;
	436	int err = 0;
	437	BlockDriverState *bs = NULL;
	438
	439	while (err == 0 && (bs = bdrv_next(bs))) {
	440	AioContext *ctx = bdrv_get_aio_context(bs);
	441
	442	aio_context_acquire(ctx);
	443	if (bdrv_can_snapshot(bs)) {
	444	err = bdrv_snapshot_find(bs, &sn, name);
	445	}
	446	aio_context_release(ctx);
	447	}
	448
	449	*first_bad_bs = bs;
	450	return err;
	451	}
a9085f9b DL	452
	453	int bdrv_all_create_snapshot(QEMUSnapshotInfo *sn,
	454	BlockDriverState *vm_state_bs,
	455	uint64_t vm_state_size,
	456	BlockDriverState **first_bad_bs)
	457	{
	458	int err = 0;
	459	BlockDriverState *bs = NULL;
	460
	461	while (err == 0 && (bs = bdrv_next(bs))) {
	462	AioContext *ctx = bdrv_get_aio_context(bs);
	463
	464	aio_context_acquire(ctx);
	465	if (bs == vm_state_bs) {
	466	sn->vm_state_size = vm_state_size;
	467	err = bdrv_snapshot_create(bs, sn);
	468	} else if (bdrv_can_snapshot(bs)) {
	469	sn->vm_state_size = 0;
	470	err = bdrv_snapshot_create(bs, sn);
	471	}
	472	aio_context_release(ctx);
	473	}
	474
	475	*first_bad_bs = bs;
	476	return err;
	477	}
7cb14481 DL	478
	479	BlockDriverState *bdrv_all_find_vmstate_bs(void)
	480	{
	481	bool not_found = true;
	482	BlockDriverState *bs = NULL;
	483
	484	while (not_found && (bs = bdrv_next(bs))) {
	485	AioContext *ctx = bdrv_get_aio_context(bs);
	486
	487	aio_context_acquire(ctx);
	488	not_found = !bdrv_can_snapshot(bs);
	489	aio_context_release(ctx);
	490	}
	491	return bs;
	492	}