Stefan Hajnoczi | 01979a9 | 2010-12-06 16:08:03 +0000 | [diff] [blame] | 1 | /* |
| 2 | * QEMU Enhanced Disk Format Consistency Check |
| 3 | * |
| 4 | * Copyright IBM, Corp. 2010 |
| 5 | * |
| 6 | * Authors: |
| 7 | * Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> |
| 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 | |
Stefan Hajnoczi | 19dfc44 | 2011-04-24 18:38:58 +0100 | [diff] [blame] | 21 | uint64_t nclusters; |
Stefan Hajnoczi | 01979a9 | 2010-12-06 16:08:03 +0000 | [diff] [blame] | 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; |
Dong Xu Wang | 11c9c61 | 2012-03-15 20:13:32 +0800 | [diff] [blame] | 71 | uint64_t last_offset = 0; |
Stefan Hajnoczi | 01979a9 | 2010-12-06 16:08:03 +0000 | [diff] [blame] | 72 | |
| 73 | for (i = 0; i < s->table_nelems; i++) { |
| 74 | uint64_t offset = table->offsets[i]; |
| 75 | |
Anthony Liguori | 21df65b | 2010-12-17 15:58:22 +0000 | [diff] [blame] | 76 | if (qed_offset_is_unalloc_cluster(offset) || |
| 77 | qed_offset_is_zero_cluster(offset)) { |
Stefan Hajnoczi | 01979a9 | 2010-12-06 16:08:03 +0000 | [diff] [blame] | 78 | continue; |
| 79 | } |
Dong Xu Wang | 11c9c61 | 2012-03-15 20:13:32 +0800 | [diff] [blame] | 80 | check->result->bfi.allocated_clusters++; |
| 81 | if (last_offset && (last_offset + s->header.cluster_size != offset)) { |
| 82 | check->result->bfi.fragmented_clusters++; |
| 83 | } |
| 84 | last_offset = offset; |
Stefan Hajnoczi | 01979a9 | 2010-12-06 16:08:03 +0000 | [diff] [blame] | 85 | |
| 86 | /* Detect invalid cluster offset */ |
| 87 | if (!qed_check_cluster_offset(s, offset)) { |
| 88 | if (check->fix) { |
| 89 | table->offsets[i] = 0; |
Kevin Wolf | ccf3471 | 2012-05-11 18:16:54 +0200 | [diff] [blame] | 90 | check->result->corruptions_fixed++; |
Stefan Hajnoczi | 01979a9 | 2010-12-06 16:08:03 +0000 | [diff] [blame] | 91 | } else { |
| 92 | check->result->corruptions++; |
| 93 | } |
| 94 | |
| 95 | num_invalid++; |
| 96 | continue; |
| 97 | } |
| 98 | |
| 99 | qed_set_used_clusters(check, offset, 1); |
| 100 | } |
| 101 | |
| 102 | return num_invalid; |
| 103 | } |
| 104 | |
| 105 | /** |
| 106 | * Descend tables and check each cluster is referenced once only |
| 107 | */ |
| 108 | static int qed_check_l1_table(QEDCheck *check, QEDTable *table) |
| 109 | { |
| 110 | BDRVQEDState *s = check->s; |
| 111 | unsigned int i, num_invalid_l1 = 0; |
| 112 | int ret, last_error = 0; |
| 113 | |
| 114 | /* Mark L1 table clusters used */ |
| 115 | qed_set_used_clusters(check, s->header.l1_table_offset, |
| 116 | s->header.table_size); |
| 117 | |
| 118 | for (i = 0; i < s->table_nelems; i++) { |
| 119 | unsigned int num_invalid_l2; |
| 120 | uint64_t offset = table->offsets[i]; |
| 121 | |
Anthony Liguori | 21df65b | 2010-12-17 15:58:22 +0000 | [diff] [blame] | 122 | if (qed_offset_is_unalloc_cluster(offset)) { |
Stefan Hajnoczi | 01979a9 | 2010-12-06 16:08:03 +0000 | [diff] [blame] | 123 | continue; |
| 124 | } |
| 125 | |
| 126 | /* Detect invalid L2 offset */ |
| 127 | if (!qed_check_table_offset(s, offset)) { |
| 128 | /* Clear invalid offset */ |
| 129 | if (check->fix) { |
| 130 | table->offsets[i] = 0; |
Kevin Wolf | ccf3471 | 2012-05-11 18:16:54 +0200 | [diff] [blame] | 131 | check->result->corruptions_fixed++; |
Stefan Hajnoczi | 01979a9 | 2010-12-06 16:08:03 +0000 | [diff] [blame] | 132 | } else { |
| 133 | check->result->corruptions++; |
| 134 | } |
| 135 | |
| 136 | num_invalid_l1++; |
| 137 | continue; |
| 138 | } |
| 139 | |
| 140 | if (!qed_set_used_clusters(check, offset, s->header.table_size)) { |
| 141 | continue; /* skip an invalid table */ |
| 142 | } |
| 143 | |
| 144 | ret = qed_read_l2_table_sync(s, &check->request, offset); |
| 145 | if (ret) { |
| 146 | check->result->check_errors++; |
| 147 | last_error = ret; |
| 148 | continue; |
| 149 | } |
| 150 | |
| 151 | num_invalid_l2 = qed_check_l2_table(check, |
| 152 | check->request.l2_table->table); |
| 153 | |
| 154 | /* Write out fixed L2 table */ |
| 155 | if (num_invalid_l2 > 0 && check->fix) { |
| 156 | ret = qed_write_l2_table_sync(s, &check->request, 0, |
| 157 | s->table_nelems, false); |
| 158 | if (ret) { |
| 159 | check->result->check_errors++; |
| 160 | last_error = ret; |
| 161 | continue; |
| 162 | } |
| 163 | } |
| 164 | } |
| 165 | |
| 166 | /* Drop reference to final table */ |
| 167 | qed_unref_l2_cache_entry(check->request.l2_table); |
| 168 | check->request.l2_table = NULL; |
| 169 | |
| 170 | /* Write out fixed L1 table */ |
| 171 | if (num_invalid_l1 > 0 && check->fix) { |
| 172 | ret = qed_write_l1_table_sync(s, 0, s->table_nelems); |
| 173 | if (ret) { |
| 174 | check->result->check_errors++; |
| 175 | last_error = ret; |
| 176 | } |
| 177 | } |
| 178 | |
| 179 | return last_error; |
| 180 | } |
| 181 | |
| 182 | /** |
| 183 | * Check for unreferenced (leaked) clusters |
| 184 | */ |
| 185 | static void qed_check_for_leaks(QEDCheck *check) |
| 186 | { |
| 187 | BDRVQEDState *s = check->s; |
Stefan Hajnoczi | 19dfc44 | 2011-04-24 18:38:58 +0100 | [diff] [blame] | 188 | uint64_t i; |
Stefan Hajnoczi | 01979a9 | 2010-12-06 16:08:03 +0000 | [diff] [blame] | 189 | |
| 190 | for (i = s->header.header_size; i < check->nclusters; i++) { |
| 191 | if (!qed_test_bit(check->used_clusters, i)) { |
| 192 | check->result->leaks++; |
| 193 | } |
| 194 | } |
| 195 | } |
| 196 | |
Stefan Hajnoczi | b10170a | 2012-08-09 13:05:54 +0100 | [diff] [blame] | 197 | /** |
| 198 | * Mark an image clean once it passes check or has been repaired |
| 199 | */ |
| 200 | static void qed_check_mark_clean(BDRVQEDState *s, BdrvCheckResult *result) |
| 201 | { |
| 202 | /* Skip if there were unfixable corruptions or I/O errors */ |
| 203 | if (result->corruptions > 0 || result->check_errors > 0) { |
| 204 | return; |
| 205 | } |
| 206 | |
| 207 | /* Skip if image is already marked clean */ |
| 208 | if (!(s->header.features & QED_F_NEED_CHECK)) { |
| 209 | return; |
| 210 | } |
| 211 | |
| 212 | /* Ensure fixes reach storage before clearing check bit */ |
| 213 | bdrv_flush(s->bs); |
| 214 | |
| 215 | s->header.features &= ~QED_F_NEED_CHECK; |
| 216 | qed_write_header_sync(s); |
| 217 | } |
| 218 | |
Stefan Hajnoczi | 01979a9 | 2010-12-06 16:08:03 +0000 | [diff] [blame] | 219 | int qed_check(BDRVQEDState *s, BdrvCheckResult *result, bool fix) |
| 220 | { |
| 221 | QEDCheck check = { |
| 222 | .s = s, |
| 223 | .result = result, |
| 224 | .nclusters = qed_bytes_to_clusters(s, s->file_size), |
| 225 | .request = { .l2_table = NULL }, |
| 226 | .fix = fix, |
| 227 | }; |
| 228 | int ret; |
| 229 | |
Anthony Liguori | 7267c09 | 2011-08-20 22:09:37 -0500 | [diff] [blame] | 230 | check.used_clusters = g_malloc0(((check.nclusters + 31) / 32) * |
Stefan Hajnoczi | 01979a9 | 2010-12-06 16:08:03 +0000 | [diff] [blame] | 231 | sizeof(check.used_clusters[0])); |
| 232 | |
Dong Xu Wang | 11c9c61 | 2012-03-15 20:13:32 +0800 | [diff] [blame] | 233 | check.result->bfi.total_clusters = |
| 234 | (s->header.image_size + s->header.cluster_size - 1) / |
| 235 | s->header.cluster_size; |
Stefan Hajnoczi | 01979a9 | 2010-12-06 16:08:03 +0000 | [diff] [blame] | 236 | ret = qed_check_l1_table(&check, s->l1_table); |
| 237 | if (ret == 0) { |
| 238 | /* Only check for leaks if entire image was scanned successfully */ |
| 239 | qed_check_for_leaks(&check); |
Stefan Hajnoczi | b10170a | 2012-08-09 13:05:54 +0100 | [diff] [blame] | 240 | |
| 241 | if (fix) { |
| 242 | qed_check_mark_clean(s, result); |
| 243 | } |
Stefan Hajnoczi | 01979a9 | 2010-12-06 16:08:03 +0000 | [diff] [blame] | 244 | } |
| 245 | |
Anthony Liguori | 7267c09 | 2011-08-20 22:09:37 -0500 | [diff] [blame] | 246 | g_free(check.used_clusters); |
Stefan Hajnoczi | 01979a9 | 2010-12-06 16:08:03 +0000 | [diff] [blame] | 247 | return ret; |
| 248 | } |