xref: /openbmc/qemu/block/snapshot.c (revision db895a1e)
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 
51 int bdrv_can_snapshot(BlockDriverState *bs)
52 {
53     BlockDriver *drv = bs->drv;
54     if (!drv || !bdrv_is_inserted(bs) || bdrv_is_read_only(bs)) {
55         return 0;
56     }
57 
58     if (!drv->bdrv_snapshot_create) {
59         if (bs->file != NULL) {
60             return bdrv_can_snapshot(bs->file);
61         }
62         return 0;
63     }
64 
65     return 1;
66 }
67 
68 int bdrv_snapshot_create(BlockDriverState *bs,
69                          QEMUSnapshotInfo *sn_info)
70 {
71     BlockDriver *drv = bs->drv;
72     if (!drv) {
73         return -ENOMEDIUM;
74     }
75     if (drv->bdrv_snapshot_create) {
76         return drv->bdrv_snapshot_create(bs, sn_info);
77     }
78     if (bs->file) {
79         return bdrv_snapshot_create(bs->file, sn_info);
80     }
81     return -ENOTSUP;
82 }
83 
84 int bdrv_snapshot_goto(BlockDriverState *bs,
85                        const char *snapshot_id)
86 {
87     BlockDriver *drv = bs->drv;
88     int ret, open_ret;
89 
90     if (!drv) {
91         return -ENOMEDIUM;
92     }
93     if (drv->bdrv_snapshot_goto) {
94         return drv->bdrv_snapshot_goto(bs, snapshot_id);
95     }
96 
97     if (bs->file) {
98         drv->bdrv_close(bs);
99         ret = bdrv_snapshot_goto(bs->file, snapshot_id);
100         open_ret = drv->bdrv_open(bs, NULL, bs->open_flags);
101         if (open_ret < 0) {
102             bdrv_delete(bs->file);
103             bs->drv = NULL;
104             return open_ret;
105         }
106         return ret;
107     }
108 
109     return -ENOTSUP;
110 }
111 
112 int bdrv_snapshot_delete(BlockDriverState *bs, const char *snapshot_id)
113 {
114     BlockDriver *drv = bs->drv;
115     if (!drv) {
116         return -ENOMEDIUM;
117     }
118     if (drv->bdrv_snapshot_delete) {
119         return drv->bdrv_snapshot_delete(bs, snapshot_id);
120     }
121     if (bs->file) {
122         return bdrv_snapshot_delete(bs->file, snapshot_id);
123     }
124     return -ENOTSUP;
125 }
126 
127 int bdrv_snapshot_list(BlockDriverState *bs,
128                        QEMUSnapshotInfo **psn_info)
129 {
130     BlockDriver *drv = bs->drv;
131     if (!drv) {
132         return -ENOMEDIUM;
133     }
134     if (drv->bdrv_snapshot_list) {
135         return drv->bdrv_snapshot_list(bs, psn_info);
136     }
137     if (bs->file) {
138         return bdrv_snapshot_list(bs->file, psn_info);
139     }
140     return -ENOTSUP;
141 }
142 
143 int bdrv_snapshot_load_tmp(BlockDriverState *bs,
144         const char *snapshot_name)
145 {
146     BlockDriver *drv = bs->drv;
147     if (!drv) {
148         return -ENOMEDIUM;
149     }
150     if (!bs->read_only) {
151         return -EINVAL;
152     }
153     if (drv->bdrv_snapshot_load_tmp) {
154         return drv->bdrv_snapshot_load_tmp(bs, snapshot_name);
155     }
156     return -ENOTSUP;
157 }
158