[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/error.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);
    }

    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) {
            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_by_id_or_name(bs, name, err);
        }
        aio_context_release(ctx);
        if (ret < 0) {
            goto fail;
        }
    }

fail:
    *first_bad_bs = bs;
    return ret;
}


int bdrv_all_goto_snapshot(const char *name, 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 (bdrv_can_snapshot(bs)) {
            err = bdrv_snapshot_goto(bs, name);
        }
        aio_context_release(ctx);
        if (err < 0) {
            goto fail;
        }
    }

fail:
    *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;
    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) {
            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) {
            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) {
            break;
        }
    }
    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"
da34e65c	28	#include "qapi/error.h"
cc7a8ea7	29	#include "qapi/qmp/qerror.h"
de08c606	30
8c116b0e WX	31	QemuOptsList internal_snapshot_opts = {
	32	.name = "snapshot",
	33	.head = QTAILQ_HEAD_INITIALIZER(internal_snapshot_opts.head),
	34	.desc = {
	35	{
	36	.name = SNAPSHOT_OPT_ID,
	37	.type = QEMU_OPT_STRING,
	38	.help = "snapshot id"
	39	},{
	40	.name = SNAPSHOT_OPT_NAME,
	41	.type = QEMU_OPT_STRING,
	42	.help = "snapshot name"
	43	},{
	44	/* end of list */
	45	}
	46	},
	47	};
	48
de08c606 WX	49	int bdrv_snapshot_find(BlockDriverState bs, QEMUSnapshotInfo sn_info,
	50	const char *name)
	51	{
	52	QEMUSnapshotInfo sn_tab, sn;
	53	int nb_sns, i, ret;
	54
	55	ret = -ENOENT;
	56	nb_sns = bdrv_snapshot_list(bs, &sn_tab);
	57	if (nb_sns < 0) {
	58	return ret;
	59	}
	60	for (i = 0; i < nb_sns; i++) {
	61	sn = &sn_tab[i];
	62	if (!strcmp(sn->id_str, name) \|\| !strcmp(sn->name, name)) {
	63	sn_info = sn;
	64	ret = 0;
	65	break;
	66	}
	67	}
	68	g_free(sn_tab);
	69	return ret;
	70	}
	71
2ea1dd75 WX	72	/**
	73	* Look up an internal snapshot by @id and @name.
	74	* @bs: block device to search
	75	* @id: unique snapshot ID, or NULL
	76	* @name: snapshot name, or NULL
	77	* @sn_info: location to store information on the snapshot found
	78	* @errp: location to store error, will be set only for exception
	79	*
	80	* This function will traverse snapshot list in @bs to search the matching
	81	* one, @id and @name are the matching condition:
	82	* If both @id and @name are specified, find the first one with id @id and
	83	* name @name.
	84	* If only @id is specified, find the first one with id @id.
	85	* If only @name is specified, find the first one with name @name.
	86	* if none is specified, abort().
	87	*
	88	* Returns: true when a snapshot is found and @sn_info will be filled, false
	89	* when error or not found. If all operation succeed but no matching one is
	90	* found, @errp will NOT be set.
	91	*/
	92	bool bdrv_snapshot_find_by_id_and_name(BlockDriverState *bs,
	93	const char *id,
	94	const char *name,
	95	QEMUSnapshotInfo *sn_info,
	96	Error **errp)
	97	{
	98	QEMUSnapshotInfo sn_tab, sn;
	99	int nb_sns, i;
	100	bool ret = false;
	101
	102	assert(id \|\| name);
	103
	104	nb_sns = bdrv_snapshot_list(bs, &sn_tab);
	105	if (nb_sns < 0) {
	106	error_setg_errno(errp, -nb_sns, "Failed to get a snapshot list");
	107	return false;
	108	} else if (nb_sns == 0) {
	109	return false;
	110	}
	111
	112	if (id && name) {
	113	for (i = 0; i < nb_sns; i++) {
	114	sn = &sn_tab[i];
	115	if (!strcmp(sn->id_str, id) && !strcmp(sn->name, name)) {
	116	sn_info = sn;
	117	ret = true;
	118	break;
	119	}
	120	}
	121	} else if (id) {
	122	for (i = 0; i < nb_sns; i++) {
	123	sn = &sn_tab[i];
	124	if (!strcmp(sn->id_str, id)) {
	125	sn_info = sn;
	126	ret = true;
	127	break;
	128	}
	129	}
	130	} else if (name) {
	131	for (i = 0; i < nb_sns; i++) {
	132	sn = &sn_tab[i];
	133	if (!strcmp(sn->name, name)) {
	134	sn_info = sn;
	135	ret = true;
136	break;
137	}
138	}
139	}
140
141	g_free(sn_tab);
142	return ret;
143	}
144
de08c606 WX	145	int bdrv_can_snapshot(BlockDriverState *bs)
	146	{
	147	BlockDriver *drv = bs->drv;
	148	if (!drv \|\| !bdrv_is_inserted(bs) \|\| bdrv_is_read_only(bs)) {
	149	return 0;
	150	}
	151
	152	if (!drv->bdrv_snapshot_create) {
	153	if (bs->file != NULL) {
9a4f4c31	154	return bdrv_can_snapshot(bs->file->bs);
de08c606 WX	155	}
	156	return 0;
	157	}
	158
	159	return 1;
	160	}
	161
	162	int bdrv_snapshot_create(BlockDriverState *bs,
	163	QEMUSnapshotInfo *sn_info)
	164	{
	165	BlockDriver *drv = bs->drv;
	166	if (!drv) {
	167	return -ENOMEDIUM;
	168	}
	169	if (drv->bdrv_snapshot_create) {
	170	return drv->bdrv_snapshot_create(bs, sn_info);
	171	}
	172	if (bs->file) {
9a4f4c31	173	return bdrv_snapshot_create(bs->file->bs, sn_info);
de08c606 WX	174	}
	175	return -ENOTSUP;
	176	}
	177
	178	int bdrv_snapshot_goto(BlockDriverState *bs,
	179	const char *snapshot_id)
	180	{
	181	BlockDriver *drv = bs->drv;
	182	int ret, open_ret;
	183
	184	if (!drv) {
	185	return -ENOMEDIUM;
	186	}
	187	if (drv->bdrv_snapshot_goto) {
	188	return drv->bdrv_snapshot_goto(bs, snapshot_id);
	189	}
	190
	191	if (bs->file) {
	192	drv->bdrv_close(bs);
9a4f4c31	193	ret = bdrv_snapshot_goto(bs->file->bs, snapshot_id);
015a1036	194	open_ret = drv->bdrv_open(bs, NULL, bs->open_flags, NULL);
de08c606	195	if (open_ret < 0) {
9a4f4c31	196	bdrv_unref(bs->file->bs);
de08c606 WX	197	bs->drv = NULL;
	198	return open_ret;
	199	}
	200	return ret;
	201	}
	202
	203	return -ENOTSUP;
	204	}
	205
a89d89d3 WX	206	/**
	207	* Delete an internal snapshot by @snapshot_id and @name.
	208	* @bs: block device used in the operation
	209	* @snapshot_id: unique snapshot ID, or NULL
	210	* @name: snapshot name, or NULL
	211	* @errp: location to store error
	212	*
	213	* If both @snapshot_id and @name are specified, delete the first one with
	214	* id @snapshot_id and name @name.
	215	* If only @snapshot_id is specified, delete the first one with id
	216	* @snapshot_id.
	217	* If only @name is specified, delete the first one with name @name.
7b4c4781	218	* if none is specified, return -EINVAL.
a89d89d3 WX	219	*
	220	* Returns: 0 on success, -errno on failure. If @bs is not inserted, return
	221	* -ENOMEDIUM. If @snapshot_id and @name are both NULL, return -EINVAL. If @bs
	222	* does not support internal snapshot deletion, return -ENOTSUP. If @bs does
	223	* not support parameter @snapshot_id or @name, or one of them is not correctly
	224	* specified, return -EINVAL. If @bs can't find one matching @id and @name,
	225	* return -ENOENT. If @errp != NULL, it will always be filled with error
	226	* message on failure.
	227	*/
	228	int bdrv_snapshot_delete(BlockDriverState *bs,
	229	const char *snapshot_id,
	230	const char *name,
	231	Error **errp)
de08c606 WX	232	{
de08c606 WX	233	BlockDriver *drv = bs->drv;
27a7649a PB	234	int ret;
27a7649a PB	235
de08c606	236	if (!drv) {
c6bd8c70	237	error_setg(errp, QERR_DEVICE_HAS_NO_MEDIUM, bdrv_get_device_name(bs));
de08c606 WX	238	return -ENOMEDIUM;
de08c606 WX	239	}
a89d89d3 WX	240	if (!snapshot_id && !name) {
	241	error_setg(errp, "snapshot_id and name are both NULL");
	242	return -EINVAL;
	243	}
3432a192 ZH	244
3432a192 ZH	245	/* drain all pending i/o before deleting snapshot */
27a7649a	246	bdrv_drained_begin(bs);
3432a192	247
de08c606	248	if (drv->bdrv_snapshot_delete) {
27a7649a PB	249	ret = drv->bdrv_snapshot_delete(bs, snapshot_id, name, errp);
	250	} else if (bs->file) {
	251	ret = bdrv_snapshot_delete(bs->file->bs, snapshot_id, name, errp);
	252	} else {
	253	error_setg(errp, "Block format '%s' used by device '%s' "
	254	"does not support internal snapshot deletion",
	255	drv->format_name, bdrv_get_device_name(bs));
	256	ret = -ENOTSUP;
de08c606	257	}
27a7649a PB	258
	259	bdrv_drained_end(bs);
	260	return ret;
de08c606 WX	261	}
de08c606 WX	262
25af925f DL	263	int bdrv_snapshot_delete_by_id_or_name(BlockDriverState *bs,
	264	const char *id_or_name,
	265	Error **errp)
a89d89d3 WX	266	{
	267	int ret;
	268	Error *local_err = NULL;
	269
	270	ret = bdrv_snapshot_delete(bs, id_or_name, NULL, &local_err);
	271	if (ret == -ENOENT \|\| ret == -EINVAL) {
	272	error_free(local_err);
	273	local_err = NULL;
	274	ret = bdrv_snapshot_delete(bs, NULL, id_or_name, &local_err);
	275	}
	276
	277	if (ret < 0) {
	278	error_propagate(errp, local_err);
	279	}
25af925f	280	return ret;
a89d89d3 WX	281	}
a89d89d3 WX	282
de08c606 WX	283	int bdrv_snapshot_list(BlockDriverState *bs,
	284	QEMUSnapshotInfo **psn_info)
	285	{
	286	BlockDriver *drv = bs->drv;
	287	if (!drv) {
	288	return -ENOMEDIUM;
	289	}
	290	if (drv->bdrv_snapshot_list) {
	291	return drv->bdrv_snapshot_list(bs, psn_info);
	292	}
	293	if (bs->file) {
9a4f4c31	294	return bdrv_snapshot_list(bs->file->bs, psn_info);
de08c606 WX	295	}
	296	return -ENOTSUP;
	297	}
	298
7b4c4781 WX	299	/**
	300	* Temporarily load an internal snapshot by @snapshot_id and @name.
	301	* @bs: block device used in the operation
	302	* @snapshot_id: unique snapshot ID, or NULL
	303	* @name: snapshot name, or NULL
	304	* @errp: location to store error
	305	*
	306	* If both @snapshot_id and @name are specified, load the first one with
	307	* id @snapshot_id and name @name.
	308	* If only @snapshot_id is specified, load the first one with id
	309	* @snapshot_id.
	310	* If only @name is specified, load the first one with name @name.
	311	* if none is specified, return -EINVAL.
	312	*
	313	* Returns: 0 on success, -errno on fail. If @bs is not inserted, return
	314	* -ENOMEDIUM. If @bs is not readonly, return -EINVAL. If @bs did not support
	315	* internal snapshot, return -ENOTSUP. If qemu can't find a matching @id and
	316	* @name, return -ENOENT. If @errp != NULL, it will always be filled on
	317	* failure.
	318	*/
de08c606	319	int bdrv_snapshot_load_tmp(BlockDriverState *bs,
7b4c4781 WX	320	const char *snapshot_id,
	321	const char *name,
	322	Error **errp)
de08c606 WX	323	{
de08c606 WX	324	BlockDriver *drv = bs->drv;
7b4c4781	325
de08c606	326	if (!drv) {
c6bd8c70	327	error_setg(errp, QERR_DEVICE_HAS_NO_MEDIUM, bdrv_get_device_name(bs));
de08c606 WX	328	return -ENOMEDIUM;
de08c606 WX	329	}
7b4c4781 WX	330	if (!snapshot_id && !name) {
	331	error_setg(errp, "snapshot_id and name are both NULL");
	332	return -EINVAL;
	333	}
de08c606	334	if (!bs->read_only) {
7b4c4781	335	error_setg(errp, "Device is not readonly");
de08c606 WX	336	return -EINVAL;
	337	}
	338	if (drv->bdrv_snapshot_load_tmp) {
7b4c4781	339	return drv->bdrv_snapshot_load_tmp(bs, snapshot_id, name, errp);
de08c606	340	}
81e5f78a AG	341	error_setg(errp, "Block format '%s' used by device '%s' "
	342	"does not support temporarily loading internal snapshots",
	343	drv->format_name, bdrv_get_device_name(bs));
de08c606 WX	344	return -ENOTSUP;
de08c606 WX	345	}
7b4c4781 WX	346
	347	int bdrv_snapshot_load_tmp_by_id_or_name(BlockDriverState *bs,
	348	const char *id_or_name,
	349	Error **errp)
	350	{
	351	int ret;
	352	Error *local_err = NULL;
	353
	354	ret = bdrv_snapshot_load_tmp(bs, id_or_name, NULL, &local_err);
	355	if (ret == -ENOENT \|\| ret == -EINVAL) {
	356	error_free(local_err);
	357	local_err = NULL;
	358	ret = bdrv_snapshot_load_tmp(bs, NULL, id_or_name, &local_err);
	359	}
	360
621ff94d	361	error_propagate(errp, local_err);
7b4c4781 WX	362
	363	return ret;
	364	}
e9ff957a DL	365
	366
	367	/* Group operations. All block drivers are involved.
	368	* These functions will properly handle dataplane (take aio_context_acquire
	369	* when appropriate for appropriate block drivers) */
	370
	371	bool bdrv_all_can_snapshot(BlockDriverState **first_bad_bs)
	372	{
	373	bool ok = true;
7c8eece4	374	BlockDriverState *bs;
88be7b4b	375	BdrvNextIterator it;
e9ff957a	376
88be7b4b	377	for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
e9ff957a DL	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);
88be7b4b KW	385	if (!ok) {
	386	goto fail;
	387	}
e9ff957a DL	388	}
e9ff957a DL	389
88be7b4b	390	fail:
e9ff957a DL	391	*first_bad_bs = bs;
	392	return ok;
	393	}
9b00ea37 DL	394
	395	int bdrv_all_delete_snapshot(const char name, BlockDriverState *first_bad_bs,
	396	Error **err)
	397	{
	398	int ret = 0;
7c8eece4	399	BlockDriverState *bs;
88be7b4b	400	BdrvNextIterator it;
9b00ea37 DL	401	QEMUSnapshotInfo sn1, *snapshot = &sn1;
9b00ea37 DL	402
88be7b4b	403	for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
9b00ea37 DL	404	AioContext *ctx = bdrv_get_aio_context(bs);
	405
	406	aio_context_acquire(ctx);
	407	if (bdrv_can_snapshot(bs) &&
	408	bdrv_snapshot_find(bs, snapshot, name) >= 0) {
	409	ret = bdrv_snapshot_delete_by_id_or_name(bs, name, err);
	410	}
	411	aio_context_release(ctx);
88be7b4b KW	412	if (ret < 0) {
	413	goto fail;
	414	}
9b00ea37 DL	415	}
9b00ea37 DL	416
88be7b4b	417	fail:
9b00ea37 DL	418	*first_bad_bs = bs;
	419	return ret;
	420	}
4c1cdbaa DL	421
	422
	423	int bdrv_all_goto_snapshot(const char name, BlockDriverState *first_bad_bs)
	424	{
	425	int err = 0;
7c8eece4	426	BlockDriverState *bs;
88be7b4b	427	BdrvNextIterator it;
4c1cdbaa	428
88be7b4b	429	for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
4c1cdbaa DL	430	AioContext *ctx = bdrv_get_aio_context(bs);
	431
	432	aio_context_acquire(ctx);
	433	if (bdrv_can_snapshot(bs)) {
	434	err = bdrv_snapshot_goto(bs, name);
	435	}
	436	aio_context_release(ctx);
88be7b4b KW	437	if (err < 0) {
	438	goto fail;
	439	}
4c1cdbaa DL	440	}
4c1cdbaa DL	441
88be7b4b	442	fail:
4c1cdbaa DL	443	*first_bad_bs = bs;
	444	return err;
	445	}
723ccda1 DL	446
	447	int bdrv_all_find_snapshot(const char name, BlockDriverState *first_bad_bs)
	448	{
	449	QEMUSnapshotInfo sn;
	450	int err = 0;
7c8eece4	451	BlockDriverState *bs;
88be7b4b	452	BdrvNextIterator it;
723ccda1	453
88be7b4b	454	for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
723ccda1 DL	455	AioContext *ctx = bdrv_get_aio_context(bs);
	456
	457	aio_context_acquire(ctx);
	458	if (bdrv_can_snapshot(bs)) {
	459	err = bdrv_snapshot_find(bs, &sn, name);
	460	}
	461	aio_context_release(ctx);
88be7b4b KW	462	if (err < 0) {
	463	goto fail;
	464	}
723ccda1 DL	465	}
723ccda1 DL	466
88be7b4b	467	fail:
723ccda1 DL	468	*first_bad_bs = bs;
	469	return err;
	470	}
a9085f9b DL	471
	472	int bdrv_all_create_snapshot(QEMUSnapshotInfo *sn,
	473	BlockDriverState *vm_state_bs,
	474	uint64_t vm_state_size,
	475	BlockDriverState **first_bad_bs)
	476	{
	477	int err = 0;
7c8eece4	478	BlockDriverState *bs;
88be7b4b	479	BdrvNextIterator it;
a9085f9b	480
88be7b4b	481	for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
a9085f9b DL	482	AioContext *ctx = bdrv_get_aio_context(bs);
	483
	484	aio_context_acquire(ctx);
	485	if (bs == vm_state_bs) {
	486	sn->vm_state_size = vm_state_size;
	487	err = bdrv_snapshot_create(bs, sn);
	488	} else if (bdrv_can_snapshot(bs)) {
	489	sn->vm_state_size = 0;
	490	err = bdrv_snapshot_create(bs, sn);
	491	}
	492	aio_context_release(ctx);
88be7b4b KW	493	if (err < 0) {
	494	goto fail;
	495	}
a9085f9b DL	496	}
a9085f9b DL	497
88be7b4b	498	fail:
a9085f9b DL	499	*first_bad_bs = bs;
	500	return err;
	501	}
7cb14481 DL	502
	503	BlockDriverState *bdrv_all_find_vmstate_bs(void)
	504	{
7c8eece4	505	BlockDriverState *bs;
88be7b4b	506	BdrvNextIterator it;
7cb14481	507
88be7b4b	508	for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
7cb14481	509	AioContext *ctx = bdrv_get_aio_context(bs);
88be7b4b	510	bool found;
7cb14481 DL	511
7cb14481 DL	512	aio_context_acquire(ctx);
88be7b4b	513	found = bdrv_can_snapshot(bs);
7cb14481	514	aio_context_release(ctx);
88be7b4b KW	515
	516	if (found) {
	517	break;
	518	}
7cb14481 DL	519	}
	520	return bs;
	521	}