![[BACK]](/cvsweb/icons/back.gif){kind=icon}
Return to qed-check.c CVS log ![[TXT]](/cvsweb/icons/text.gif){kind=icon}
![[DIR]](/cvsweb/icons/dir.gif){kind=icon}
Up to [Qemu by Fabrice Bellard] / qemu / block|
Return to qed-check.c CVS log | Up to [Qemu by Fabrice Bellard] / qemu / block |
1.1 root 1: /*
2: * QEMU Enhanced Disk Format Consistency Check
3: *
4: * Copyright IBM, Corp. 2010
5: *
6: * Authors:
7: * Stefan Hajnoczi <[email protected]>
8: *
9: * This work is licensed under the terms of the GNU LGPL, version 2 or later.
10: * See the COPYING.LIB file in the top-level directory.
11: *
12: */
13:
14: #include "qed.h"
15:
16: typedef struct {
17: BDRVQEDState *s;
18: BdrvCheckResult *result;
19: bool fix; /* whether to fix invalid offsets */
20:
1.1.1.2 root 21: uint64_t nclusters;
1.1 root 22: uint32_t *used_clusters; /* referenced cluster bitmap */
23:
24: QEDRequest request;
25: } QEDCheck;
26:
27: static bool qed_test_bit(uint32_t *bitmap, uint64_t n) {
28: return !!(bitmap[n / 32] & (1 << (n % 32)));
29: }
30:
31: static void qed_set_bit(uint32_t *bitmap, uint64_t n) {
32: bitmap[n / 32] |= 1 << (n % 32);
33: }
34:
35: /**
36: * Set bitmap bits for clusters
37: *
38: * @check: Check structure
39: * @offset: Starting offset in bytes
40: * @n: Number of clusters
41: */
42: static bool qed_set_used_clusters(QEDCheck *check, uint64_t offset,
43: unsigned int n)
44: {
45: uint64_t cluster = qed_bytes_to_clusters(check->s, offset);
46: unsigned int corruptions = 0;
47:
48: while (n-- != 0) {
49: /* Clusters should only be referenced once */
50: if (qed_test_bit(check->used_clusters, cluster)) {
51: corruptions++;
52: }
53:
54: qed_set_bit(check->used_clusters, cluster);
55: cluster++;
56: }
57:
58: check->result->corruptions += corruptions;
59: return corruptions == 0;
60: }
61:
62: /**
63: * Check an L2 table
64: *
65: * @ret: Number of invalid cluster offsets
66: */
67: static unsigned int qed_check_l2_table(QEDCheck *check, QEDTable *table)
68: {
69: BDRVQEDState *s = check->s;
70: unsigned int i, num_invalid = 0;
71:
72: for (i = 0; i < s->table_nelems; i++) {
73: uint64_t offset = table->offsets[i];
74:
1.1.1.3 root 75: if (qed_offset_is_unalloc_cluster(offset) ||
76: qed_offset_is_zero_cluster(offset)) {
1.1 root 77: continue;
78: }
79:
80: /* Detect invalid cluster offset */
81: if (!qed_check_cluster_offset(s, offset)) {
82: if (check->fix) {
83: table->offsets[i] = 0;
84: } else {
85: check->result->corruptions++;
86: }
87:
88: num_invalid++;
89: continue;
90: }
91:
92: qed_set_used_clusters(check, offset, 1);
93: }
94:
95: return num_invalid;
96: }
97:
98: /**
99: * Descend tables and check each cluster is referenced once only
100: */
101: static int qed_check_l1_table(QEDCheck *check, QEDTable *table)
102: {
103: BDRVQEDState *s = check->s;
104: unsigned int i, num_invalid_l1 = 0;
105: int ret, last_error = 0;
106:
107: /* Mark L1 table clusters used */
108: qed_set_used_clusters(check, s->header.l1_table_offset,
109: s->header.table_size);
110:
111: for (i = 0; i < s->table_nelems; i++) {
112: unsigned int num_invalid_l2;
113: uint64_t offset = table->offsets[i];
114:
1.1.1.3 root 115: if (qed_offset_is_unalloc_cluster(offset)) {
1.1 root 116: continue;
117: }
118:
119: /* Detect invalid L2 offset */
120: if (!qed_check_table_offset(s, offset)) {
121: /* Clear invalid offset */
122: if (check->fix) {
123: table->offsets[i] = 0;
124: } else {
125: check->result->corruptions++;
126: }
127:
128: num_invalid_l1++;
129: continue;
130: }
131:
132: if (!qed_set_used_clusters(check, offset, s->header.table_size)) {
133: continue; /* skip an invalid table */
134: }
135:
136: ret = qed_read_l2_table_sync(s, &check->request, offset);
137: if (ret) {
138: check->result->check_errors++;
139: last_error = ret;
140: continue;
141: }
142:
143: num_invalid_l2 = qed_check_l2_table(check,
144: check->request.l2_table->table);
145:
146: /* Write out fixed L2 table */
147: if (num_invalid_l2 > 0 && check->fix) {
148: ret = qed_write_l2_table_sync(s, &check->request, 0,
149: s->table_nelems, false);
150: if (ret) {
151: check->result->check_errors++;
152: last_error = ret;
153: continue;
154: }
155: }
156: }
157:
158: /* Drop reference to final table */
159: qed_unref_l2_cache_entry(check->request.l2_table);
160: check->request.l2_table = NULL;
161:
162: /* Write out fixed L1 table */
163: if (num_invalid_l1 > 0 && check->fix) {
164: ret = qed_write_l1_table_sync(s, 0, s->table_nelems);
165: if (ret) {
166: check->result->check_errors++;
167: last_error = ret;
168: }
169: }
170:
171: return last_error;
172: }
173:
174: /**
175: * Check for unreferenced (leaked) clusters
176: */
177: static void qed_check_for_leaks(QEDCheck *check)
178: {
179: BDRVQEDState *s = check->s;
1.1.1.2 root 180: uint64_t i;
1.1 root 181:
182: for (i = s->header.header_size; i < check->nclusters; i++) {
183: if (!qed_test_bit(check->used_clusters, i)) {
184: check->result->leaks++;
185: }
186: }
187: }
188:
189: int qed_check(BDRVQEDState *s, BdrvCheckResult *result, bool fix)
190: {
191: QEDCheck check = {
192: .s = s,
193: .result = result,
194: .nclusters = qed_bytes_to_clusters(s, s->file_size),
195: .request = { .l2_table = NULL },
196: .fix = fix,
197: };
198: int ret;
199:
1.1.1.4 ! root 200: check.used_clusters = g_malloc0(((check.nclusters + 31) / 32) *
1.1 root 201: sizeof(check.used_clusters[0]));
202:
203: ret = qed_check_l1_table(&check, s->l1_table);
204: if (ret == 0) {
205: /* Only check for leaks if entire image was scanned successfully */
206: qed_check_for_leaks(&check);
207: }
208:
1.1.1.4 ! root 209: g_free(check.used_clusters);
1.1 root 210: return ret;
211: }
This archive runs on limited infrastructure. Preserving old code on modern bandwidth. Automated agents are requested to crawl responsibly.