vhost: add migration block if memfd failed
[qemu/ar7.git] / block / snapshot.c
blob49e143e99107b79964f5ba65e7f29fa52fb39ecb
1 /*
2 * Block layer snapshot related functions
4 * Copyright (c) 2003-2008 Fabrice Bellard
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:
13 * The above copyright notice and this permission notice shall be included in
14 * all copies or substantial portions of the Software.
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.
25 #include "block/snapshot.h"
26 #include "block/block_int.h"
27 #include "qapi/qmp/qerror.h"
29 QemuOptsList internal_snapshot_opts = {
30 .name = "snapshot",
31 .head = QTAILQ_HEAD_INITIALIZER(internal_snapshot_opts.head),
32 .desc = {
34 .name = SNAPSHOT_OPT_ID,
35 .type = QEMU_OPT_STRING,
36 .help = "snapshot id"
37 },{
38 .name = SNAPSHOT_OPT_NAME,
39 .type = QEMU_OPT_STRING,
40 .help = "snapshot name"
41 },{
42 /* end of list */
47 int bdrv_snapshot_find(BlockDriverState *bs, QEMUSnapshotInfo *sn_info,
48 const char *name)
50 QEMUSnapshotInfo *sn_tab, *sn;
51 int nb_sns, i, ret;
53 ret = -ENOENT;
54 nb_sns = bdrv_snapshot_list(bs, &sn_tab);
55 if (nb_sns < 0) {
56 return ret;
58 for (i = 0; i < nb_sns; i++) {
59 sn = &sn_tab[i];
60 if (!strcmp(sn->id_str, name) || !strcmp(sn->name, name)) {
61 *sn_info = *sn;
62 ret = 0;
63 break;
66 g_free(sn_tab);
67 return ret;
70 /**
71 * Look up an internal snapshot by @id and @name.
72 * @bs: block device to search
73 * @id: unique snapshot ID, or NULL
74 * @name: snapshot name, or NULL
75 * @sn_info: location to store information on the snapshot found
76 * @errp: location to store error, will be set only for exception
78 * This function will traverse snapshot list in @bs to search the matching
79 * one, @id and @name are the matching condition:
80 * If both @id and @name are specified, find the first one with id @id and
81 * name @name.
82 * If only @id is specified, find the first one with id @id.
83 * If only @name is specified, find the first one with name @name.
84 * if none is specified, abort().
86 * Returns: true when a snapshot is found and @sn_info will be filled, false
87 * when error or not found. If all operation succeed but no matching one is
88 * found, @errp will NOT be set.
90 bool bdrv_snapshot_find_by_id_and_name(BlockDriverState *bs,
91 const char *id,
92 const char *name,
93 QEMUSnapshotInfo *sn_info,
94 Error **errp)
96 QEMUSnapshotInfo *sn_tab, *sn;
97 int nb_sns, i;
98 bool ret = false;
100 assert(id || name);
102 nb_sns = bdrv_snapshot_list(bs, &sn_tab);
103 if (nb_sns < 0) {
104 error_setg_errno(errp, -nb_sns, "Failed to get a snapshot list");
105 return false;
106 } else if (nb_sns == 0) {
107 return false;
110 if (id && name) {
111 for (i = 0; i < nb_sns; i++) {
112 sn = &sn_tab[i];
113 if (!strcmp(sn->id_str, id) && !strcmp(sn->name, name)) {
114 *sn_info = *sn;
115 ret = true;
116 break;
119 } else if (id) {
120 for (i = 0; i < nb_sns; i++) {
121 sn = &sn_tab[i];
122 if (!strcmp(sn->id_str, id)) {
123 *sn_info = *sn;
124 ret = true;
125 break;
128 } else if (name) {
129 for (i = 0; i < nb_sns; i++) {
130 sn = &sn_tab[i];
131 if (!strcmp(sn->name, name)) {
132 *sn_info = *sn;
133 ret = true;
134 break;
139 g_free(sn_tab);
140 return ret;
143 int bdrv_can_snapshot(BlockDriverState *bs)
145 BlockDriver *drv = bs->drv;
146 if (!drv || !bdrv_is_inserted(bs) || bdrv_is_read_only(bs)) {
147 return 0;
150 if (!drv->bdrv_snapshot_create) {
151 if (bs->file != NULL) {
152 return bdrv_can_snapshot(bs->file);
154 return 0;
157 return 1;
160 int bdrv_snapshot_create(BlockDriverState *bs,
161 QEMUSnapshotInfo *sn_info)
163 BlockDriver *drv = bs->drv;
164 if (!drv) {
165 return -ENOMEDIUM;
167 if (drv->bdrv_snapshot_create) {
168 return drv->bdrv_snapshot_create(bs, sn_info);
170 if (bs->file) {
171 return bdrv_snapshot_create(bs->file, sn_info);
173 return -ENOTSUP;
176 int bdrv_snapshot_goto(BlockDriverState *bs,
177 const char *snapshot_id)
179 BlockDriver *drv = bs->drv;
180 int ret, open_ret;
182 if (!drv) {
183 return -ENOMEDIUM;
185 if (drv->bdrv_snapshot_goto) {
186 return drv->bdrv_snapshot_goto(bs, snapshot_id);
189 if (bs->file) {
190 drv->bdrv_close(bs);
191 ret = bdrv_snapshot_goto(bs->file, snapshot_id);
192 open_ret = drv->bdrv_open(bs, NULL, bs->open_flags, NULL);
193 if (open_ret < 0) {
194 bdrv_unref(bs->file);
195 bs->drv = NULL;
196 return open_ret;
198 return ret;
201 return -ENOTSUP;
205 * Delete an internal snapshot by @snapshot_id and @name.
206 * @bs: block device used in the operation
207 * @snapshot_id: unique snapshot ID, or NULL
208 * @name: snapshot name, or NULL
209 * @errp: location to store error
211 * If both @snapshot_id and @name are specified, delete the first one with
212 * id @snapshot_id and name @name.
213 * If only @snapshot_id is specified, delete the first one with id
214 * @snapshot_id.
215 * If only @name is specified, delete the first one with name @name.
216 * if none is specified, return -EINVAL.
218 * Returns: 0 on success, -errno on failure. If @bs is not inserted, return
219 * -ENOMEDIUM. If @snapshot_id and @name are both NULL, return -EINVAL. If @bs
220 * does not support internal snapshot deletion, return -ENOTSUP. If @bs does
221 * not support parameter @snapshot_id or @name, or one of them is not correctly
222 * specified, return -EINVAL. If @bs can't find one matching @id and @name,
223 * return -ENOENT. If @errp != NULL, it will always be filled with error
224 * message on failure.
226 int bdrv_snapshot_delete(BlockDriverState *bs,
227 const char *snapshot_id,
228 const char *name,
229 Error **errp)
231 BlockDriver *drv = bs->drv;
232 if (!drv) {
233 error_setg(errp, QERR_DEVICE_HAS_NO_MEDIUM, bdrv_get_device_name(bs));
234 return -ENOMEDIUM;
236 if (!snapshot_id && !name) {
237 error_setg(errp, "snapshot_id and name are both NULL");
238 return -EINVAL;
241 /* drain all pending i/o before deleting snapshot */
242 bdrv_drain(bs);
244 if (drv->bdrv_snapshot_delete) {
245 return drv->bdrv_snapshot_delete(bs, snapshot_id, name, errp);
247 if (bs->file) {
248 return bdrv_snapshot_delete(bs->file, snapshot_id, name, errp);
250 error_setg(errp, "Block format '%s' used by device '%s' "
251 "does not support internal snapshot deletion",
252 drv->format_name, bdrv_get_device_name(bs));
253 return -ENOTSUP;
256 void bdrv_snapshot_delete_by_id_or_name(BlockDriverState *bs,
257 const char *id_or_name,
258 Error **errp)
260 int ret;
261 Error *local_err = NULL;
263 ret = bdrv_snapshot_delete(bs, id_or_name, NULL, &local_err);
264 if (ret == -ENOENT || ret == -EINVAL) {
265 error_free(local_err);
266 local_err = NULL;
267 ret = bdrv_snapshot_delete(bs, NULL, id_or_name, &local_err);
270 if (ret < 0) {
271 error_propagate(errp, local_err);
275 int bdrv_snapshot_list(BlockDriverState *bs,
276 QEMUSnapshotInfo **psn_info)
278 BlockDriver *drv = bs->drv;
279 if (!drv) {
280 return -ENOMEDIUM;
282 if (drv->bdrv_snapshot_list) {
283 return drv->bdrv_snapshot_list(bs, psn_info);
285 if (bs->file) {
286 return bdrv_snapshot_list(bs->file, psn_info);
288 return -ENOTSUP;
292 * Temporarily load an internal snapshot by @snapshot_id and @name.
293 * @bs: block device used in the operation
294 * @snapshot_id: unique snapshot ID, or NULL
295 * @name: snapshot name, or NULL
296 * @errp: location to store error
298 * If both @snapshot_id and @name are specified, load the first one with
299 * id @snapshot_id and name @name.
300 * If only @snapshot_id is specified, load the first one with id
301 * @snapshot_id.
302 * If only @name is specified, load the first one with name @name.
303 * if none is specified, return -EINVAL.
305 * Returns: 0 on success, -errno on fail. If @bs is not inserted, return
306 * -ENOMEDIUM. If @bs is not readonly, return -EINVAL. If @bs did not support
307 * internal snapshot, return -ENOTSUP. If qemu can't find a matching @id and
308 * @name, return -ENOENT. If @errp != NULL, it will always be filled on
309 * failure.
311 int bdrv_snapshot_load_tmp(BlockDriverState *bs,
312 const char *snapshot_id,
313 const char *name,
314 Error **errp)
316 BlockDriver *drv = bs->drv;
318 if (!drv) {
319 error_setg(errp, QERR_DEVICE_HAS_NO_MEDIUM, bdrv_get_device_name(bs));
320 return -ENOMEDIUM;
322 if (!snapshot_id && !name) {
323 error_setg(errp, "snapshot_id and name are both NULL");
324 return -EINVAL;
326 if (!bs->read_only) {
327 error_setg(errp, "Device is not readonly");
328 return -EINVAL;
330 if (drv->bdrv_snapshot_load_tmp) {
331 return drv->bdrv_snapshot_load_tmp(bs, snapshot_id, name, errp);
333 error_setg(errp, "Block format '%s' used by device '%s' "
334 "does not support temporarily loading internal snapshots",
335 drv->format_name, bdrv_get_device_name(bs));
336 return -ENOTSUP;
339 int bdrv_snapshot_load_tmp_by_id_or_name(BlockDriverState *bs,
340 const char *id_or_name,
341 Error **errp)
343 int ret;
344 Error *local_err = NULL;
346 ret = bdrv_snapshot_load_tmp(bs, id_or_name, NULL, &local_err);
347 if (ret == -ENOENT || ret == -EINVAL) {
348 error_free(local_err);
349 local_err = NULL;
350 ret = bdrv_snapshot_load_tmp(bs, NULL, id_or_name, &local_err);
353 if (local_err) {
354 error_propagate(errp, local_err);
357 return ret;