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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);
1.1.1.5 root 82: if (bdrv_pread(bs->file, offset, &h, sizeof(h)) != sizeof(h))
1.1 root 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);
1.1.1.5 root 100: if (bdrv_pread(bs->file, offset, sn->id_str, id_str_size) != id_str_size)
1.1 root 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);
1.1.1.5 root 106: if (bdrv_pread(bs->file, offset, sn->name, name_size) != name_size)
1.1 root 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 */
1.1.1.6 root 119: static int qcow2_write_snapshots(BlockDriverState *bs)
1.1 root 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);
1.1.1.6 root 141: bdrv_flush(bs->file);
1.1 root 142: offset = snapshots_offset;
1.1.1.3 root 143: if (offset < 0) {
144: return offset;
145: }
1.1 root 146:
147: for(i = 0; i < s->nb_snapshots; i++) {
148: sn = s->snapshots + i;
149: memset(&h, 0, sizeof(h));
150: h.l1_table_offset = cpu_to_be64(sn->l1_table_offset);
151: h.l1_size = cpu_to_be32(sn->l1_size);
152: h.vm_state_size = cpu_to_be32(sn->vm_state_size);
153: h.date_sec = cpu_to_be32(sn->date_sec);
154: h.date_nsec = cpu_to_be32(sn->date_nsec);
155: h.vm_clock_nsec = cpu_to_be64(sn->vm_clock_nsec);
156:
157: id_str_size = strlen(sn->id_str);
158: name_size = strlen(sn->name);
159: h.id_str_size = cpu_to_be16(id_str_size);
160: h.name_size = cpu_to_be16(name_size);
161: offset = align_offset(offset, 8);
1.1.1.5 root 162: if (bdrv_pwrite_sync(bs->file, offset, &h, sizeof(h)) < 0)
1.1 root 163: goto fail;
164: offset += sizeof(h);
1.1.1.5 root 165: if (bdrv_pwrite_sync(bs->file, offset, sn->id_str, id_str_size) < 0)
1.1 root 166: goto fail;
167: offset += id_str_size;
1.1.1.5 root 168: if (bdrv_pwrite_sync(bs->file, offset, sn->name, name_size) < 0)
1.1 root 169: goto fail;
170: offset += name_size;
171: }
172:
173: /* update the various header fields */
174: data64 = cpu_to_be64(snapshots_offset);
1.1.1.5 root 175: if (bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, snapshots_offset),
1.1.1.4 root 176: &data64, sizeof(data64)) < 0)
1.1 root 177: goto fail;
178: data32 = cpu_to_be32(s->nb_snapshots);
1.1.1.5 root 179: if (bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, nb_snapshots),
1.1.1.4 root 180: &data32, sizeof(data32)) < 0)
1.1 root 181: goto fail;
182:
183: /* free the old snapshot table */
184: qcow2_free_clusters(bs, s->snapshots_offset, s->snapshots_size);
185: s->snapshots_offset = snapshots_offset;
186: s->snapshots_size = snapshots_size;
187: return 0;
188: fail:
189: return -1;
190: }
191:
192: static void find_new_snapshot_id(BlockDriverState *bs,
193: char *id_str, int id_str_size)
194: {
195: BDRVQcowState *s = bs->opaque;
196: QCowSnapshot *sn;
197: int i, id, id_max = 0;
198:
199: for(i = 0; i < s->nb_snapshots; i++) {
200: sn = s->snapshots + i;
201: id = strtoul(sn->id_str, NULL, 10);
202: if (id > id_max)
203: id_max = id;
204: }
205: snprintf(id_str, id_str_size, "%d", id_max + 1);
206: }
207:
208: static int find_snapshot_by_id(BlockDriverState *bs, const char *id_str)
209: {
210: BDRVQcowState *s = bs->opaque;
211: int i;
212:
213: for(i = 0; i < s->nb_snapshots; i++) {
214: if (!strcmp(s->snapshots[i].id_str, id_str))
215: return i;
216: }
217: return -1;
218: }
219:
220: static int find_snapshot_by_id_or_name(BlockDriverState *bs, const char *name)
221: {
222: BDRVQcowState *s = bs->opaque;
223: int i, ret;
224:
225: ret = find_snapshot_by_id(bs, name);
226: if (ret >= 0)
227: return ret;
228: for(i = 0; i < s->nb_snapshots; i++) {
229: if (!strcmp(s->snapshots[i].name, name))
230: return i;
231: }
232: return -1;
233: }
234:
235: /* if no id is provided, a new one is constructed */
236: int qcow2_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info)
237: {
238: BDRVQcowState *s = bs->opaque;
239: QCowSnapshot *snapshots1, sn1, *sn = &sn1;
240: int i, ret;
241: uint64_t *l1_table = NULL;
1.1.1.3 root 242: int64_t l1_table_offset;
1.1 root 243:
244: memset(sn, 0, sizeof(*sn));
245:
246: if (sn_info->id_str[0] == '\0') {
247: /* compute a new id */
248: find_new_snapshot_id(bs, sn_info->id_str, sizeof(sn_info->id_str));
249: }
250:
251: /* check that the ID is unique */
252: if (find_snapshot_by_id(bs, sn_info->id_str) >= 0)
253: return -ENOENT;
254:
255: sn->id_str = qemu_strdup(sn_info->id_str);
256: if (!sn->id_str)
257: goto fail;
258: sn->name = qemu_strdup(sn_info->name);
259: if (!sn->name)
260: goto fail;
261: sn->vm_state_size = sn_info->vm_state_size;
262: sn->date_sec = sn_info->date_sec;
263: sn->date_nsec = sn_info->date_nsec;
264: sn->vm_clock_nsec = sn_info->vm_clock_nsec;
265:
266: ret = qcow2_update_snapshot_refcount(bs, s->l1_table_offset, s->l1_size, 1);
267: if (ret < 0)
268: goto fail;
269:
270: /* create the L1 table of the snapshot */
1.1.1.3 root 271: l1_table_offset = qcow2_alloc_clusters(bs, s->l1_size * sizeof(uint64_t));
272: if (l1_table_offset < 0) {
273: goto fail;
274: }
1.1.1.6 root 275: bdrv_flush(bs->file);
1.1.1.3 root 276:
277: sn->l1_table_offset = l1_table_offset;
1.1 root 278: sn->l1_size = s->l1_size;
279:
1.1.1.2 root 280: if (s->l1_size != 0) {
281: l1_table = qemu_malloc(s->l1_size * sizeof(uint64_t));
282: } else {
283: l1_table = NULL;
284: }
285:
1.1 root 286: for(i = 0; i < s->l1_size; i++) {
287: l1_table[i] = cpu_to_be64(s->l1_table[i]);
288: }
1.1.1.5 root 289: if (bdrv_pwrite_sync(bs->file, sn->l1_table_offset,
1.1.1.4 root 290: l1_table, s->l1_size * sizeof(uint64_t)) < 0)
1.1 root 291: goto fail;
292: qemu_free(l1_table);
293: l1_table = NULL;
294:
295: snapshots1 = qemu_malloc((s->nb_snapshots + 1) * sizeof(QCowSnapshot));
296: if (s->snapshots) {
297: memcpy(snapshots1, s->snapshots, s->nb_snapshots * sizeof(QCowSnapshot));
298: qemu_free(s->snapshots);
299: }
300: s->snapshots = snapshots1;
301: s->snapshots[s->nb_snapshots++] = *sn;
302:
1.1.1.6 root 303: if (qcow2_write_snapshots(bs) < 0)
1.1 root 304: goto fail;
305: #ifdef DEBUG_ALLOC
306: qcow2_check_refcounts(bs);
307: #endif
308: return 0;
309: fail:
310: qemu_free(sn->name);
311: qemu_free(l1_table);
312: return -1;
313: }
314:
315: /* copy the snapshot 'snapshot_name' into the current disk image */
316: int qcow2_snapshot_goto(BlockDriverState *bs, const char *snapshot_id)
317: {
318: BDRVQcowState *s = bs->opaque;
319: QCowSnapshot *sn;
1.1.1.7 ! root 320: int i, snapshot_index;
! 321: int cur_l1_bytes, sn_l1_bytes;
1.1 root 322:
323: snapshot_index = find_snapshot_by_id_or_name(bs, snapshot_id);
324: if (snapshot_index < 0)
325: return -ENOENT;
326: sn = &s->snapshots[snapshot_index];
327:
328: if (qcow2_update_snapshot_refcount(bs, s->l1_table_offset, s->l1_size, -1) < 0)
329: goto fail;
330:
1.1.1.6 root 331: if (qcow2_grow_l1_table(bs, sn->l1_size, true) < 0)
1.1 root 332: goto fail;
333:
1.1.1.7 ! root 334: cur_l1_bytes = s->l1_size * sizeof(uint64_t);
! 335: sn_l1_bytes = sn->l1_size * sizeof(uint64_t);
! 336:
! 337: if (cur_l1_bytes > sn_l1_bytes) {
! 338: memset(s->l1_table + sn->l1_size, 0, cur_l1_bytes - sn_l1_bytes);
! 339: }
! 340:
1.1 root 341: /* copy the snapshot l1 table to the current l1 table */
1.1.1.5 root 342: if (bdrv_pread(bs->file, sn->l1_table_offset,
1.1.1.7 ! root 343: s->l1_table, sn_l1_bytes) < 0)
1.1 root 344: goto fail;
1.1.1.5 root 345: if (bdrv_pwrite_sync(bs->file, s->l1_table_offset,
1.1.1.7 ! root 346: s->l1_table, cur_l1_bytes) < 0)
1.1 root 347: goto fail;
348: for(i = 0;i < s->l1_size; i++) {
349: be64_to_cpus(&s->l1_table[i]);
350: }
351:
352: if (qcow2_update_snapshot_refcount(bs, s->l1_table_offset, s->l1_size, 1) < 0)
353: goto fail;
354:
355: #ifdef DEBUG_ALLOC
356: qcow2_check_refcounts(bs);
357: #endif
358: return 0;
359: fail:
360: return -EIO;
361: }
362:
363: int qcow2_snapshot_delete(BlockDriverState *bs, const char *snapshot_id)
364: {
365: BDRVQcowState *s = bs->opaque;
366: QCowSnapshot *sn;
367: int snapshot_index, ret;
368:
369: snapshot_index = find_snapshot_by_id_or_name(bs, snapshot_id);
370: if (snapshot_index < 0)
371: return -ENOENT;
372: sn = &s->snapshots[snapshot_index];
373:
374: ret = qcow2_update_snapshot_refcount(bs, sn->l1_table_offset, sn->l1_size, -1);
375: if (ret < 0)
376: return ret;
377: /* must update the copied flag on the current cluster offsets */
378: ret = qcow2_update_snapshot_refcount(bs, s->l1_table_offset, s->l1_size, 0);
379: if (ret < 0)
380: return ret;
381: qcow2_free_clusters(bs, sn->l1_table_offset, sn->l1_size * sizeof(uint64_t));
382:
383: qemu_free(sn->id_str);
384: qemu_free(sn->name);
385: memmove(sn, sn + 1, (s->nb_snapshots - snapshot_index - 1) * sizeof(*sn));
386: s->nb_snapshots--;
1.1.1.6 root 387: ret = qcow2_write_snapshots(bs);
1.1 root 388: if (ret < 0) {
389: /* XXX: restore snapshot if error ? */
390: return ret;
391: }
392: #ifdef DEBUG_ALLOC
393: qcow2_check_refcounts(bs);
394: #endif
395: return 0;
396: }
397:
398: int qcow2_snapshot_list(BlockDriverState *bs, QEMUSnapshotInfo **psn_tab)
399: {
400: BDRVQcowState *s = bs->opaque;
401: QEMUSnapshotInfo *sn_tab, *sn_info;
402: QCowSnapshot *sn;
403: int i;
404:
405: if (!s->nb_snapshots) {
406: *psn_tab = NULL;
407: return s->nb_snapshots;
408: }
409:
410: sn_tab = qemu_mallocz(s->nb_snapshots * sizeof(QEMUSnapshotInfo));
411: for(i = 0; i < s->nb_snapshots; i++) {
412: sn_info = sn_tab + i;
413: sn = s->snapshots + i;
414: pstrcpy(sn_info->id_str, sizeof(sn_info->id_str),
415: sn->id_str);
416: pstrcpy(sn_info->name, sizeof(sn_info->name),
417: sn->name);
418: sn_info->vm_state_size = sn->vm_state_size;
419: sn_info->date_sec = sn->date_sec;
420: sn_info->date_nsec = sn->date_nsec;
421: sn_info->vm_clock_nsec = sn->vm_clock_nsec;
422: }
423: *psn_tab = sn_tab;
424: return s->nb_snapshots;
425: }
426:
1.1.1.6 root 427: int qcow2_snapshot_load_tmp(BlockDriverState *bs, const char *snapshot_name)
428: {
429: int i, snapshot_index, l1_size2;
430: BDRVQcowState *s = bs->opaque;
431: QCowSnapshot *sn;
432:
433: snapshot_index = find_snapshot_by_id_or_name(bs, snapshot_name);
434: if (snapshot_index < 0) {
435: return -ENOENT;
436: }
437:
438: sn = &s->snapshots[snapshot_index];
439: s->l1_size = sn->l1_size;
440: l1_size2 = s->l1_size * sizeof(uint64_t);
441: if (s->l1_table != NULL) {
442: qemu_free(s->l1_table);
443: }
444:
445: s->l1_table_offset = sn->l1_table_offset;
446: s->l1_table = qemu_mallocz(align_offset(l1_size2, 512));
447:
448: if (bdrv_pread(bs->file, sn->l1_table_offset,
449: s->l1_table, l1_size2) != l1_size2) {
450: return -1;
451: }
452:
453: for(i = 0;i < s->l1_size; i++) {
454: be64_to_cpus(&s->l1_table[i]);
455: }
456: return 0;
457: }
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