[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 "block/snapshot.h"
#include "block/block_int.h"

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 -ENINVAL.
 *
 * 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_set(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 (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_set(errp, QERR_BLOCK_FORMAT_FEATURE_NOT_SUPPORTED,
              drv->format_name, bdrv_get_device_name(bs),
              "internal snapshot deletion");
    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;
}

int bdrv_snapshot_load_tmp(BlockDriverState *bs,
        const char *snapshot_name)
{
    BlockDriver *drv = bs->drv;
    if (!drv) {
        return -ENOMEDIUM;
    }
    if (!bs->read_only) {
        return -EINVAL;
    }
    if (drv->bdrv_snapshot_load_tmp) {
        return drv->bdrv_snapshot_load_tmp(bs, snapshot_name);
    }
    return -ENOTSUP;
}
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
	25	#include "block/snapshot.h"
	26	#include "block/block_int.h"
	27
	28	int bdrv_snapshot_find(BlockDriverState bs, QEMUSnapshotInfo sn_info,
	29	const char *name)
	30	{
	31	QEMUSnapshotInfo sn_tab, sn;
	32	int nb_sns, i, ret;
	33
	34	ret = -ENOENT;
	35	nb_sns = bdrv_snapshot_list(bs, &sn_tab);
	36	if (nb_sns < 0) {
	37	return ret;
	38	}
	39	for (i = 0; i < nb_sns; i++) {
	40	sn = &sn_tab[i];
	41	if (!strcmp(sn->id_str, name) \|\| !strcmp(sn->name, name)) {
	42	sn_info = sn;
	43	ret = 0;
	44	break;
	45	}
	46	}
	47	g_free(sn_tab);
	48	return ret;
	49	}
	50
2ea1dd75 WX	51	/**
	52	* Look up an internal snapshot by @id and @name.
	53	* @bs: block device to search
	54	* @id: unique snapshot ID, or NULL
	55	* @name: snapshot name, or NULL
	56	* @sn_info: location to store information on the snapshot found
	57	* @errp: location to store error, will be set only for exception
	58	*
	59	* This function will traverse snapshot list in @bs to search the matching
	60	* one, @id and @name are the matching condition:
	61	* If both @id and @name are specified, find the first one with id @id and
	62	* name @name.
	63	* If only @id is specified, find the first one with id @id.
	64	* If only @name is specified, find the first one with name @name.
	65	* if none is specified, abort().
	66	*
	67	* Returns: true when a snapshot is found and @sn_info will be filled, false
	68	* when error or not found. If all operation succeed but no matching one is
	69	* found, @errp will NOT be set.
	70	*/
	71	bool bdrv_snapshot_find_by_id_and_name(BlockDriverState *bs,
	72	const char *id,
	73	const char *name,
	74	QEMUSnapshotInfo *sn_info,
	75	Error **errp)
	76	{
	77	QEMUSnapshotInfo sn_tab, sn;
	78	int nb_sns, i;
	79	bool ret = false;
	80
	81	assert(id \|\| name);
	82
	83	nb_sns = bdrv_snapshot_list(bs, &sn_tab);
	84	if (nb_sns < 0) {
	85	error_setg_errno(errp, -nb_sns, "Failed to get a snapshot list");
	86	return false;
	87	} else if (nb_sns == 0) {
	88	return false;
	89	}
	90
	91	if (id && name) {
	92	for (i = 0; i < nb_sns; i++) {
	93	sn = &sn_tab[i];
	94	if (!strcmp(sn->id_str, id) && !strcmp(sn->name, name)) {
	95	sn_info = sn;
	96	ret = true;
	97	break;
	98	}
	99	}
	100	} else if (id) {
	101	for (i = 0; i < nb_sns; i++) {
	102	sn = &sn_tab[i];
	103	if (!strcmp(sn->id_str, id)) {
	104	sn_info = sn;
	105	ret = true;
	106	break;
	107	}
	108	}
	109	} else if (name) {
	110	for (i = 0; i < nb_sns; i++) {
	111	sn = &sn_tab[i];
	112	if (!strcmp(sn->name, name)) {
	113	sn_info = sn;
	114	ret = true;
115	break;
116	}
117	}
118	}
119
120	g_free(sn_tab);
121	return ret;
122	}
123
de08c606 WX	124	int bdrv_can_snapshot(BlockDriverState *bs)
	125	{
	126	BlockDriver *drv = bs->drv;
	127	if (!drv \|\| !bdrv_is_inserted(bs) \|\| bdrv_is_read_only(bs)) {
	128	return 0;
	129	}
	130
	131	if (!drv->bdrv_snapshot_create) {
	132	if (bs->file != NULL) {
	133	return bdrv_can_snapshot(bs->file);
	134	}
	135	return 0;
	136	}
	137
	138	return 1;
	139	}
	140
	141	int bdrv_snapshot_create(BlockDriverState *bs,
	142	QEMUSnapshotInfo *sn_info)
	143	{
	144	BlockDriver *drv = bs->drv;
	145	if (!drv) {
	146	return -ENOMEDIUM;
	147	}
	148	if (drv->bdrv_snapshot_create) {
	149	return drv->bdrv_snapshot_create(bs, sn_info);
	150	}
	151	if (bs->file) {
	152	return bdrv_snapshot_create(bs->file, sn_info);
	153	}
	154	return -ENOTSUP;
	155	}
	156
	157	int bdrv_snapshot_goto(BlockDriverState *bs,
	158	const char *snapshot_id)
	159	{
	160	BlockDriver *drv = bs->drv;
	161	int ret, open_ret;
	162
	163	if (!drv) {
	164	return -ENOMEDIUM;
	165	}
	166	if (drv->bdrv_snapshot_goto) {
	167	return drv->bdrv_snapshot_goto(bs, snapshot_id);
	168	}
	169
	170	if (bs->file) {
	171	drv->bdrv_close(bs);
	172	ret = bdrv_snapshot_goto(bs->file, snapshot_id);
015a1036	173	open_ret = drv->bdrv_open(bs, NULL, bs->open_flags, NULL);
de08c606	174	if (open_ret < 0) {
4f6fd349	175	bdrv_unref(bs->file);
de08c606 WX	176	bs->drv = NULL;
	177	return open_ret;
	178	}
	179	return ret;
	180	}
	181
	182	return -ENOTSUP;
	183	}
	184
a89d89d3 WX	185	/**
	186	* Delete an internal snapshot by @snapshot_id and @name.
	187	* @bs: block device used in the operation
	188	* @snapshot_id: unique snapshot ID, or NULL
	189	* @name: snapshot name, or NULL
	190	* @errp: location to store error
	191	*
	192	* If both @snapshot_id and @name are specified, delete the first one with
	193	* id @snapshot_id and name @name.
	194	* If only @snapshot_id is specified, delete the first one with id
	195	* @snapshot_id.
	196	* If only @name is specified, delete the first one with name @name.
	197	* if none is specified, return -ENINVAL.
	198	*
	199	* Returns: 0 on success, -errno on failure. If @bs is not inserted, return
	200	* -ENOMEDIUM. If @snapshot_id and @name are both NULL, return -EINVAL. If @bs
	201	* does not support internal snapshot deletion, return -ENOTSUP. If @bs does
	202	* not support parameter @snapshot_id or @name, or one of them is not correctly
	203	* specified, return -EINVAL. If @bs can't find one matching @id and @name,
	204	* return -ENOENT. If @errp != NULL, it will always be filled with error
	205	* message on failure.
	206	*/
	207	int bdrv_snapshot_delete(BlockDriverState *bs,
	208	const char *snapshot_id,
	209	const char *name,
	210	Error **errp)
de08c606 WX	211	{
	212	BlockDriver *drv = bs->drv;
	213	if (!drv) {
a89d89d3	214	error_set(errp, QERR_DEVICE_HAS_NO_MEDIUM, bdrv_get_device_name(bs));
de08c606 WX	215	return -ENOMEDIUM;
de08c606 WX	216	}
a89d89d3 WX	217	if (!snapshot_id && !name) {
	218	error_setg(errp, "snapshot_id and name are both NULL");
	219	return -EINVAL;
	220	}
de08c606	221	if (drv->bdrv_snapshot_delete) {
a89d89d3	222	return drv->bdrv_snapshot_delete(bs, snapshot_id, name, errp);
de08c606 WX	223	}
de08c606 WX	224	if (bs->file) {
a89d89d3	225	return bdrv_snapshot_delete(bs->file, snapshot_id, name, errp);
de08c606	226	}
a89d89d3 WX	227	error_set(errp, QERR_BLOCK_FORMAT_FEATURE_NOT_SUPPORTED,
	228	drv->format_name, bdrv_get_device_name(bs),
	229	"internal snapshot deletion");
de08c606 WX	230	return -ENOTSUP;
	231	}
	232
a89d89d3 WX	233	void bdrv_snapshot_delete_by_id_or_name(BlockDriverState *bs,
	234	const char *id_or_name,
	235	Error **errp)
	236	{
	237	int ret;
	238	Error *local_err = NULL;
	239
	240	ret = bdrv_snapshot_delete(bs, id_or_name, NULL, &local_err);
	241	if (ret == -ENOENT \|\| ret == -EINVAL) {
	242	error_free(local_err);
	243	local_err = NULL;
	244	ret = bdrv_snapshot_delete(bs, NULL, id_or_name, &local_err);
	245	}
	246
	247	if (ret < 0) {
	248	error_propagate(errp, local_err);
	249	}
	250	}
	251
de08c606 WX	252	int bdrv_snapshot_list(BlockDriverState *bs,
	253	QEMUSnapshotInfo **psn_info)
	254	{
	255	BlockDriver *drv = bs->drv;
	256	if (!drv) {
	257	return -ENOMEDIUM;
	258	}
	259	if (drv->bdrv_snapshot_list) {
	260	return drv->bdrv_snapshot_list(bs, psn_info);
	261	}
	262	if (bs->file) {
	263	return bdrv_snapshot_list(bs->file, psn_info);
	264	}
	265	return -ENOTSUP;
	266	}
	267
	268	int bdrv_snapshot_load_tmp(BlockDriverState *bs,
	269	const char *snapshot_name)
	270	{
	271	BlockDriver *drv = bs->drv;
	272	if (!drv) {
	273	return -ENOMEDIUM;
	274	}
	275	if (!bs->read_only) {
	276	return -EINVAL;
	277	}
	278	if (drv->bdrv_snapshot_load_tmp) {
	279	return drv->bdrv_snapshot_load_tmp(bs, snapshot_name);
	280	}
	281	return -ENOTSUP;
	282	}