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1.1 root 1: /*
2: * Block driver for the QCOW version 2 format
3: *
4: * Copyright (c) 2004-2006 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 "qemu-common.h"
26: #include "block_int.h"
27: #include "block/qcow2.h"
28:
29: typedef struct __attribute__((packed)) QCowSnapshotHeader {
30: /* header is 8 byte aligned */
31: uint64_t l1_table_offset;
32:
33: uint32_t l1_size;
34: uint16_t id_str_size;
35: uint16_t name_size;
36:
37: uint32_t date_sec;
38: uint32_t date_nsec;
39:
40: uint64_t vm_clock_nsec;
41:
42: uint32_t vm_state_size;
43: uint32_t extra_data_size; /* for extension */
44: /* extra data follows */
45: /* id_str follows */
46: /* name follows */
47: } QCowSnapshotHeader;
48:
49: void qcow2_free_snapshots(BlockDriverState *bs)
50: {
51: BDRVQcowState *s = bs->opaque;
52: int i;
53:
54: for(i = 0; i < s->nb_snapshots; i++) {
55: qemu_free(s->snapshots[i].name);
56: qemu_free(s->snapshots[i].id_str);
57: }
58: qemu_free(s->snapshots);
59: s->snapshots = NULL;
60: s->nb_snapshots = 0;
61: }
62:
63: int qcow2_read_snapshots(BlockDriverState *bs)
64: {
65: BDRVQcowState *s = bs->opaque;
66: QCowSnapshotHeader h;
67: QCowSnapshot *sn;
68: int i, id_str_size, name_size;
69: int64_t offset;
70: uint32_t extra_data_size;
71:
72: if (!s->nb_snapshots) {
73: s->snapshots = NULL;
74: s->snapshots_size = 0;
75: return 0;
76: }
77:
78: offset = s->snapshots_offset;
79: s->snapshots = qemu_mallocz(s->nb_snapshots * sizeof(QCowSnapshot));
80: for(i = 0; i < s->nb_snapshots; i++) {
81: offset = align_offset(offset, 8);
82: if (bdrv_pread(s->hd, offset, &h, sizeof(h)) != sizeof(h))
83: goto fail;
84: offset += sizeof(h);
85: sn = s->snapshots + i;
86: sn->l1_table_offset = be64_to_cpu(h.l1_table_offset);
87: sn->l1_size = be32_to_cpu(h.l1_size);
88: sn->vm_state_size = be32_to_cpu(h.vm_state_size);
89: sn->date_sec = be32_to_cpu(h.date_sec);
90: sn->date_nsec = be32_to_cpu(h.date_nsec);
91: sn->vm_clock_nsec = be64_to_cpu(h.vm_clock_nsec);
92: extra_data_size = be32_to_cpu(h.extra_data_size);
93:
94: id_str_size = be16_to_cpu(h.id_str_size);
95: name_size = be16_to_cpu(h.name_size);
96:
97: offset += extra_data_size;
98:
99: sn->id_str = qemu_malloc(id_str_size + 1);
100: if (bdrv_pread(s->hd, offset, sn->id_str, id_str_size) != id_str_size)
101: goto fail;
102: offset += id_str_size;
103: sn->id_str[id_str_size] = '\0';
104:
105: sn->name = qemu_malloc(name_size + 1);
106: if (bdrv_pread(s->hd, offset, sn->name, name_size) != name_size)
107: goto fail;
108: offset += name_size;
109: sn->name[name_size] = '\0';
110: }
111: s->snapshots_size = offset - s->snapshots_offset;
112: return 0;
113: fail:
114: qcow2_free_snapshots(bs);
115: return -1;
116: }
117:
118: /* add at the end of the file a new list of snapshots */
119: static int qcow_write_snapshots(BlockDriverState *bs)
120: {
121: BDRVQcowState *s = bs->opaque;
122: QCowSnapshot *sn;
123: QCowSnapshotHeader h;
124: int i, name_size, id_str_size, snapshots_size;
125: uint64_t data64;
126: uint32_t data32;
127: int64_t offset, snapshots_offset;
128:
129: /* compute the size of the snapshots */
130: offset = 0;
131: for(i = 0; i < s->nb_snapshots; i++) {
132: sn = s->snapshots + i;
133: offset = align_offset(offset, 8);
134: offset += sizeof(h);
135: offset += strlen(sn->id_str);
136: offset += strlen(sn->name);
137: }
138: snapshots_size = offset;
139:
140: snapshots_offset = qcow2_alloc_clusters(bs, snapshots_size);
141: offset = snapshots_offset;
1.1.1.3 ! root 142: if (offset < 0) {
! 143: return offset;
! 144: }
1.1 root 145:
146: for(i = 0; i < s->nb_snapshots; i++) {
147: sn = s->snapshots + i;
148: memset(&h, 0, sizeof(h));
149: h.l1_table_offset = cpu_to_be64(sn->l1_table_offset);
150: h.l1_size = cpu_to_be32(sn->l1_size);
151: h.vm_state_size = cpu_to_be32(sn->vm_state_size);
152: h.date_sec = cpu_to_be32(sn->date_sec);
153: h.date_nsec = cpu_to_be32(sn->date_nsec);
154: h.vm_clock_nsec = cpu_to_be64(sn->vm_clock_nsec);
155:
156: id_str_size = strlen(sn->id_str);
157: name_size = strlen(sn->name);
158: h.id_str_size = cpu_to_be16(id_str_size);
159: h.name_size = cpu_to_be16(name_size);
160: offset = align_offset(offset, 8);
161: if (bdrv_pwrite(s->hd, offset, &h, sizeof(h)) != sizeof(h))
162: goto fail;
163: offset += sizeof(h);
164: if (bdrv_pwrite(s->hd, offset, sn->id_str, id_str_size) != id_str_size)
165: goto fail;
166: offset += id_str_size;
167: if (bdrv_pwrite(s->hd, offset, sn->name, name_size) != name_size)
168: goto fail;
169: offset += name_size;
170: }
171:
172: /* update the various header fields */
173: data64 = cpu_to_be64(snapshots_offset);
174: if (bdrv_pwrite(s->hd, offsetof(QCowHeader, snapshots_offset),
175: &data64, sizeof(data64)) != sizeof(data64))
176: goto fail;
177: data32 = cpu_to_be32(s->nb_snapshots);
178: if (bdrv_pwrite(s->hd, offsetof(QCowHeader, nb_snapshots),
179: &data32, sizeof(data32)) != sizeof(data32))
180: goto fail;
181:
182: /* free the old snapshot table */
183: qcow2_free_clusters(bs, s->snapshots_offset, s->snapshots_size);
184: s->snapshots_offset = snapshots_offset;
185: s->snapshots_size = snapshots_size;
186: return 0;
187: fail:
188: return -1;
189: }
190:
191: static void find_new_snapshot_id(BlockDriverState *bs,
192: char *id_str, int id_str_size)
193: {
194: BDRVQcowState *s = bs->opaque;
195: QCowSnapshot *sn;
196: int i, id, id_max = 0;
197:
198: for(i = 0; i < s->nb_snapshots; i++) {
199: sn = s->snapshots + i;
200: id = strtoul(sn->id_str, NULL, 10);
201: if (id > id_max)
202: id_max = id;
203: }
204: snprintf(id_str, id_str_size, "%d", id_max + 1);
205: }
206:
207: static int find_snapshot_by_id(BlockDriverState *bs, const char *id_str)
208: {
209: BDRVQcowState *s = bs->opaque;
210: int i;
211:
212: for(i = 0; i < s->nb_snapshots; i++) {
213: if (!strcmp(s->snapshots[i].id_str, id_str))
214: return i;
215: }
216: return -1;
217: }
218:
219: static int find_snapshot_by_id_or_name(BlockDriverState *bs, const char *name)
220: {
221: BDRVQcowState *s = bs->opaque;
222: int i, ret;
223:
224: ret = find_snapshot_by_id(bs, name);
225: if (ret >= 0)
226: return ret;
227: for(i = 0; i < s->nb_snapshots; i++) {
228: if (!strcmp(s->snapshots[i].name, name))
229: return i;
230: }
231: return -1;
232: }
233:
234: /* if no id is provided, a new one is constructed */
235: int qcow2_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info)
236: {
237: BDRVQcowState *s = bs->opaque;
238: QCowSnapshot *snapshots1, sn1, *sn = &sn1;
239: int i, ret;
240: uint64_t *l1_table = NULL;
1.1.1.3 ! root 241: int64_t l1_table_offset;
1.1 root 242:
243: memset(sn, 0, sizeof(*sn));
244:
245: if (sn_info->id_str[0] == '\0') {
246: /* compute a new id */
247: find_new_snapshot_id(bs, sn_info->id_str, sizeof(sn_info->id_str));
248: }
249:
250: /* check that the ID is unique */
251: if (find_snapshot_by_id(bs, sn_info->id_str) >= 0)
252: return -ENOENT;
253:
254: sn->id_str = qemu_strdup(sn_info->id_str);
255: if (!sn->id_str)
256: goto fail;
257: sn->name = qemu_strdup(sn_info->name);
258: if (!sn->name)
259: goto fail;
260: sn->vm_state_size = sn_info->vm_state_size;
261: sn->date_sec = sn_info->date_sec;
262: sn->date_nsec = sn_info->date_nsec;
263: sn->vm_clock_nsec = sn_info->vm_clock_nsec;
264:
265: ret = qcow2_update_snapshot_refcount(bs, s->l1_table_offset, s->l1_size, 1);
266: if (ret < 0)
267: goto fail;
268:
269: /* create the L1 table of the snapshot */
1.1.1.3 ! root 270: l1_table_offset = qcow2_alloc_clusters(bs, s->l1_size * sizeof(uint64_t));
! 271: if (l1_table_offset < 0) {
! 272: goto fail;
! 273: }
! 274:
! 275: sn->l1_table_offset = l1_table_offset;
1.1 root 276: sn->l1_size = s->l1_size;
277:
1.1.1.2 root 278: if (s->l1_size != 0) {
279: l1_table = qemu_malloc(s->l1_size * sizeof(uint64_t));
280: } else {
281: l1_table = NULL;
282: }
283:
1.1 root 284: for(i = 0; i < s->l1_size; i++) {
285: l1_table[i] = cpu_to_be64(s->l1_table[i]);
286: }
287: if (bdrv_pwrite(s->hd, sn->l1_table_offset,
288: l1_table, s->l1_size * sizeof(uint64_t)) !=
289: (s->l1_size * sizeof(uint64_t)))
290: goto fail;
291: qemu_free(l1_table);
292: l1_table = NULL;
293:
294: snapshots1 = qemu_malloc((s->nb_snapshots + 1) * sizeof(QCowSnapshot));
295: if (s->snapshots) {
296: memcpy(snapshots1, s->snapshots, s->nb_snapshots * sizeof(QCowSnapshot));
297: qemu_free(s->snapshots);
298: }
299: s->snapshots = snapshots1;
300: s->snapshots[s->nb_snapshots++] = *sn;
301:
302: if (qcow_write_snapshots(bs) < 0)
303: goto fail;
304: #ifdef DEBUG_ALLOC
305: qcow2_check_refcounts(bs);
306: #endif
307: return 0;
308: fail:
309: qemu_free(sn->name);
310: qemu_free(l1_table);
311: return -1;
312: }
313:
314: /* copy the snapshot 'snapshot_name' into the current disk image */
315: int qcow2_snapshot_goto(BlockDriverState *bs, const char *snapshot_id)
316: {
317: BDRVQcowState *s = bs->opaque;
318: QCowSnapshot *sn;
319: int i, snapshot_index, l1_size2;
320:
321: snapshot_index = find_snapshot_by_id_or_name(bs, snapshot_id);
322: if (snapshot_index < 0)
323: return -ENOENT;
324: sn = &s->snapshots[snapshot_index];
325:
326: if (qcow2_update_snapshot_refcount(bs, s->l1_table_offset, s->l1_size, -1) < 0)
327: goto fail;
328:
329: if (qcow2_grow_l1_table(bs, sn->l1_size) < 0)
330: goto fail;
331:
332: s->l1_size = sn->l1_size;
333: l1_size2 = s->l1_size * sizeof(uint64_t);
334: /* copy the snapshot l1 table to the current l1 table */
335: if (bdrv_pread(s->hd, sn->l1_table_offset,
336: s->l1_table, l1_size2) != l1_size2)
337: goto fail;
338: if (bdrv_pwrite(s->hd, s->l1_table_offset,
339: s->l1_table, l1_size2) != l1_size2)
340: goto fail;
341: for(i = 0;i < s->l1_size; i++) {
342: be64_to_cpus(&s->l1_table[i]);
343: }
344:
345: if (qcow2_update_snapshot_refcount(bs, s->l1_table_offset, s->l1_size, 1) < 0)
346: goto fail;
347:
348: #ifdef DEBUG_ALLOC
349: qcow2_check_refcounts(bs);
350: #endif
351: return 0;
352: fail:
353: return -EIO;
354: }
355:
356: int qcow2_snapshot_delete(BlockDriverState *bs, const char *snapshot_id)
357: {
358: BDRVQcowState *s = bs->opaque;
359: QCowSnapshot *sn;
360: int snapshot_index, ret;
361:
362: snapshot_index = find_snapshot_by_id_or_name(bs, snapshot_id);
363: if (snapshot_index < 0)
364: return -ENOENT;
365: sn = &s->snapshots[snapshot_index];
366:
367: ret = qcow2_update_snapshot_refcount(bs, sn->l1_table_offset, sn->l1_size, -1);
368: if (ret < 0)
369: return ret;
370: /* must update the copied flag on the current cluster offsets */
371: ret = qcow2_update_snapshot_refcount(bs, s->l1_table_offset, s->l1_size, 0);
372: if (ret < 0)
373: return ret;
374: qcow2_free_clusters(bs, sn->l1_table_offset, sn->l1_size * sizeof(uint64_t));
375:
376: qemu_free(sn->id_str);
377: qemu_free(sn->name);
378: memmove(sn, sn + 1, (s->nb_snapshots - snapshot_index - 1) * sizeof(*sn));
379: s->nb_snapshots--;
380: ret = qcow_write_snapshots(bs);
381: if (ret < 0) {
382: /* XXX: restore snapshot if error ? */
383: return ret;
384: }
385: #ifdef DEBUG_ALLOC
386: qcow2_check_refcounts(bs);
387: #endif
388: return 0;
389: }
390:
391: int qcow2_snapshot_list(BlockDriverState *bs, QEMUSnapshotInfo **psn_tab)
392: {
393: BDRVQcowState *s = bs->opaque;
394: QEMUSnapshotInfo *sn_tab, *sn_info;
395: QCowSnapshot *sn;
396: int i;
397:
398: if (!s->nb_snapshots) {
399: *psn_tab = NULL;
400: return s->nb_snapshots;
401: }
402:
403: sn_tab = qemu_mallocz(s->nb_snapshots * sizeof(QEMUSnapshotInfo));
404: for(i = 0; i < s->nb_snapshots; i++) {
405: sn_info = sn_tab + i;
406: sn = s->snapshots + i;
407: pstrcpy(sn_info->id_str, sizeof(sn_info->id_str),
408: sn->id_str);
409: pstrcpy(sn_info->name, sizeof(sn_info->name),
410: sn->name);
411: sn_info->vm_state_size = sn->vm_state_size;
412: sn_info->date_sec = sn->date_sec;
413: sn_info->date_nsec = sn->date_nsec;
414: sn_info->vm_clock_nsec = sn->vm_clock_nsec;
415: }
416: *psn_tab = sn_tab;
417: return s->nb_snapshots;
418: }
419:
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