1 /* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License (the "License"). 6 * You may not use this file except in compliance with the License. 7 * 8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 9 * or http://www.opensolaris.org/os/licensing. 10 * See the License for the specific language governing permissions 11 * and limitations under the License. 12 * 13 * When distributing Covered Code, include this CDDL HEADER in each 14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 15 * If applicable, add the following below this CDDL HEADER, with the 16 * fields enclosed by brackets "[]" replaced with your own identifying 17 * information: Portions Copyright [yyyy] [name of copyright owner] 18 * 19 * CDDL HEADER END 20 */ 21 /* 22 * Copyright (c) 2006, 2010, Oracle and/or its affiliates. All rights reserved. 23 * Copyright (c) 2013 by Delphix. All rights reserved. 24 */ 25 26 /* 27 * Routines to manage the on-disk persistent error log. 28 * 29 * Each pool stores a log of all logical data errors seen during normal 30 * operation. This is actually the union of two distinct logs: the last log, 31 * and the current log. All errors seen are logged to the current log. When a 32 * scrub completes, the current log becomes the last log, the last log is thrown 33 * out, and the current log is reinitialized. This way, if an error is somehow 34 * corrected, a new scrub will show that that it no longer exists, and will be 35 * deleted from the log when the scrub completes. 36 * 37 * The log is stored using a ZAP object whose key is a string form of the 38 * zbookmark tuple (objset, object, level, blkid), and whose contents is an 39 * optional 'objset:object' human-readable string describing the data. When an 40 * error is first logged, this string will be empty, indicating that no name is 41 * known. This prevents us from having to issue a potentially large amount of 42 * I/O to discover the object name during an error path. Instead, we do the 43 * calculation when the data is requested, storing the result so future queries 44 * will be faster. 45 * 46 * This log is then shipped into an nvlist where the key is the dataset name and 47 * the value is the object name. Userland is then responsible for uniquifying 48 * this list and displaying it to the user. 49 */ 50 51 #include <sys/dmu_tx.h> 52 #include <sys/spa.h> 53 #include <sys/spa_impl.h> 54 #include <sys/zap.h> 55 #include <sys/zio.h> 56 57 58 /* 59 * Convert a bookmark to a string. 60 */ 61 static void 62 bookmark_to_name(zbookmark_t *zb, char *buf, size_t len) 63 { 64 (void) snprintf(buf, len, "%llx:%llx:%llx:%llx", 65 (u_longlong_t)zb->zb_objset, (u_longlong_t)zb->zb_object, 66 (u_longlong_t)zb->zb_level, (u_longlong_t)zb->zb_blkid); 67 } 68 69 /* 70 * Convert a string to a bookmark 71 */ 72 #ifdef _KERNEL 73 static void 74 name_to_bookmark(char *buf, zbookmark_t *zb) 75 { 76 zb->zb_objset = strtonum(buf, &buf); 77 ASSERT(*buf == ':'); 78 zb->zb_object = strtonum(buf + 1, &buf); 79 ASSERT(*buf == ':'); 80 zb->zb_level = (int)strtonum(buf + 1, &buf); 81 ASSERT(*buf == ':'); 82 zb->zb_blkid = strtonum(buf + 1, &buf); 83 ASSERT(*buf == '\0'); 84 } 85 #endif 86 87 /* 88 * Log an uncorrectable error to the persistent error log. We add it to the 89 * spa's list of pending errors. The changes are actually synced out to disk 90 * during spa_errlog_sync(). 91 */ 92 void 93 spa_log_error(spa_t *spa, zio_t *zio) 94 { 95 zbookmark_t *zb = &zio->io_logical->io_bookmark; 96 spa_error_entry_t search; 97 spa_error_entry_t *new; 98 avl_tree_t *tree; 99 avl_index_t where; 100 101 /* 102 * If we are trying to import a pool, ignore any errors, as we won't be 103 * writing to the pool any time soon. 104 */ 105 if (spa_load_state(spa) == SPA_LOAD_TRYIMPORT) 106 return; 107 108 mutex_enter(&spa->spa_errlist_lock); 109 110 /* 111 * If we have had a request to rotate the log, log it to the next list 112 * instead of the current one. 113 */ 114 if (spa->spa_scrub_active || spa->spa_scrub_finished) 115 tree = &spa->spa_errlist_scrub; 116 else 117 tree = &spa->spa_errlist_last; 118 119 search.se_bookmark = *zb; 120 if (avl_find(tree, &search, &where) != NULL) { 121 mutex_exit(&spa->spa_errlist_lock); 122 return; 123 } 124 125 new = kmem_zalloc(sizeof (spa_error_entry_t), KM_SLEEP); 126 new->se_bookmark = *zb; 127 avl_insert(tree, new, where); 128 129 mutex_exit(&spa->spa_errlist_lock); 130 } 131 132 /* 133 * Return the number of errors currently in the error log. This is actually the 134 * sum of both the last log and the current log, since we don't know the union 135 * of these logs until we reach userland. 136 */ 137 uint64_t 138 spa_get_errlog_size(spa_t *spa) 139 { 140 uint64_t total = 0, count; 141 142 mutex_enter(&spa->spa_errlog_lock); 143 if (spa->spa_errlog_scrub != 0 && 144 zap_count(spa->spa_meta_objset, spa->spa_errlog_scrub, 145 &count) == 0) 146 total += count; 147 148 if (spa->spa_errlog_last != 0 && !spa->spa_scrub_finished && 149 zap_count(spa->spa_meta_objset, spa->spa_errlog_last, 150 &count) == 0) 151 total += count; 152 mutex_exit(&spa->spa_errlog_lock); 153 154 mutex_enter(&spa->spa_errlist_lock); 155 total += avl_numnodes(&spa->spa_errlist_last); 156 total += avl_numnodes(&spa->spa_errlist_scrub); 157 mutex_exit(&spa->spa_errlist_lock); 158 159 return (total); 160 } 161 162 #ifdef _KERNEL 163 static int 164 process_error_log(spa_t *spa, uint64_t obj, void *addr, size_t *count) 165 { 166 zap_cursor_t zc; 167 zap_attribute_t za; 168 zbookmark_t zb; 169 170 if (obj == 0) 171 return (0); 172 173 for (zap_cursor_init(&zc, spa->spa_meta_objset, obj); 174 zap_cursor_retrieve(&zc, &za) == 0; 175 zap_cursor_advance(&zc)) { 176 177 if (*count == 0) { 178 zap_cursor_fini(&zc); 179 return (SET_ERROR(ENOMEM)); 180 } 181 182 name_to_bookmark(za.za_name, &zb); 183 184 if (copyout(&zb, (char *)addr + 185 (*count - 1) * sizeof (zbookmark_t), 186 sizeof (zbookmark_t)) != 0) 187 return (SET_ERROR(EFAULT)); 188 189 *count -= 1; 190 } 191 192 zap_cursor_fini(&zc); 193 194 return (0); 195 } 196 197 static int 198 process_error_list(avl_tree_t *list, void *addr, size_t *count) 199 { 200 spa_error_entry_t *se; 201 202 for (se = avl_first(list); se != NULL; se = AVL_NEXT(list, se)) { 203 204 if (*count == 0) 205 return (SET_ERROR(ENOMEM)); 206 207 if (copyout(&se->se_bookmark, (char *)addr + 208 (*count - 1) * sizeof (zbookmark_t), 209 sizeof (zbookmark_t)) != 0) 210 return (SET_ERROR(EFAULT)); 211 212 *count -= 1; 213 } 214 215 return (0); 216 } 217 #endif 218 219 /* 220 * Copy all known errors to userland as an array of bookmarks. This is 221 * actually a union of the on-disk last log and current log, as well as any 222 * pending error requests. 223 * 224 * Because the act of reading the on-disk log could cause errors to be 225 * generated, we have two separate locks: one for the error log and one for the 226 * in-core error lists. We only need the error list lock to log and error, so 227 * we grab the error log lock while we read the on-disk logs, and only pick up 228 * the error list lock when we are finished. 229 */ 230 int 231 spa_get_errlog(spa_t *spa, void *uaddr, size_t *count) 232 { 233 int ret = 0; 234 235 #ifdef _KERNEL 236 mutex_enter(&spa->spa_errlog_lock); 237 238 ret = process_error_log(spa, spa->spa_errlog_scrub, uaddr, count); 239 240 if (!ret && !spa->spa_scrub_finished) 241 ret = process_error_log(spa, spa->spa_errlog_last, uaddr, 242 count); 243 244 mutex_enter(&spa->spa_errlist_lock); 245 if (!ret) 246 ret = process_error_list(&spa->spa_errlist_scrub, uaddr, 247 count); 248 if (!ret) 249 ret = process_error_list(&spa->spa_errlist_last, uaddr, 250 count); 251 mutex_exit(&spa->spa_errlist_lock); 252 253 mutex_exit(&spa->spa_errlog_lock); 254 #endif 255 256 return (ret); 257 } 258 259 /* 260 * Called when a scrub completes. This simply set a bit which tells which AVL 261 * tree to add new errors. spa_errlog_sync() is responsible for actually 262 * syncing the changes to the underlying objects. 263 */ 264 void 265 spa_errlog_rotate(spa_t *spa) 266 { 267 mutex_enter(&spa->spa_errlist_lock); 268 spa->spa_scrub_finished = B_TRUE; 269 mutex_exit(&spa->spa_errlist_lock); 270 } 271 272 /* 273 * Discard any pending errors from the spa_t. Called when unloading a faulted 274 * pool, as the errors encountered during the open cannot be synced to disk. 275 */ 276 void 277 spa_errlog_drain(spa_t *spa) 278 { 279 spa_error_entry_t *se; 280 void *cookie; 281 282 mutex_enter(&spa->spa_errlist_lock); 283 284 cookie = NULL; 285 while ((se = avl_destroy_nodes(&spa->spa_errlist_last, 286 &cookie)) != NULL) 287 kmem_free(se, sizeof (spa_error_entry_t)); 288 cookie = NULL; 289 while ((se = avl_destroy_nodes(&spa->spa_errlist_scrub, 290 &cookie)) != NULL) 291 kmem_free(se, sizeof (spa_error_entry_t)); 292 293 mutex_exit(&spa->spa_errlist_lock); 294 } 295 296 /* 297 * Process a list of errors into the current on-disk log. 298 */ 299 static void 300 sync_error_list(spa_t *spa, avl_tree_t *t, uint64_t *obj, dmu_tx_t *tx) 301 { 302 spa_error_entry_t *se; 303 char buf[64]; 304 void *cookie; 305 306 if (avl_numnodes(t) != 0) { 307 /* create log if necessary */ 308 if (*obj == 0) 309 *obj = zap_create(spa->spa_meta_objset, 310 DMU_OT_ERROR_LOG, DMU_OT_NONE, 311 0, tx); 312 313 /* add errors to the current log */ 314 for (se = avl_first(t); se != NULL; se = AVL_NEXT(t, se)) { 315 char *name = se->se_name ? se->se_name : ""; 316 317 bookmark_to_name(&se->se_bookmark, buf, sizeof (buf)); 318 319 (void) zap_update(spa->spa_meta_objset, 320 *obj, buf, 1, strlen(name) + 1, name, tx); 321 } 322 323 /* purge the error list */ 324 cookie = NULL; 325 while ((se = avl_destroy_nodes(t, &cookie)) != NULL) 326 kmem_free(se, sizeof (spa_error_entry_t)); 327 } 328 } 329 330 /* 331 * Sync the error log out to disk. This is a little tricky because the act of 332 * writing the error log requires the spa_errlist_lock. So, we need to lock the 333 * error lists, take a copy of the lists, and then reinitialize them. Then, we 334 * drop the error list lock and take the error log lock, at which point we 335 * do the errlog processing. Then, if we encounter an I/O error during this 336 * process, we can successfully add the error to the list. Note that this will 337 * result in the perpetual recycling of errors, but it is an unlikely situation 338 * and not a performance critical operation. 339 */ 340 void 341 spa_errlog_sync(spa_t *spa, uint64_t txg) 342 { 343 dmu_tx_t *tx; 344 avl_tree_t scrub, last; 345 int scrub_finished; 346 347 mutex_enter(&spa->spa_errlist_lock); 348 349 /* 350 * Bail out early under normal circumstances. 351 */ 352 if (avl_numnodes(&spa->spa_errlist_scrub) == 0 && 353 avl_numnodes(&spa->spa_errlist_last) == 0 && 354 !spa->spa_scrub_finished) { 355 mutex_exit(&spa->spa_errlist_lock); 356 return; 357 } 358 359 spa_get_errlists(spa, &last, &scrub); 360 scrub_finished = spa->spa_scrub_finished; 361 spa->spa_scrub_finished = B_FALSE; 362 363 mutex_exit(&spa->spa_errlist_lock); 364 mutex_enter(&spa->spa_errlog_lock); 365 366 tx = dmu_tx_create_assigned(spa->spa_dsl_pool, txg); 367 368 /* 369 * Sync out the current list of errors. 370 */ 371 sync_error_list(spa, &last, &spa->spa_errlog_last, tx); 372 373 /* 374 * Rotate the log if necessary. 375 */ 376 if (scrub_finished) { 377 if (spa->spa_errlog_last != 0) 378 VERIFY(dmu_object_free(spa->spa_meta_objset, 379 spa->spa_errlog_last, tx) == 0); 380 spa->spa_errlog_last = spa->spa_errlog_scrub; 381 spa->spa_errlog_scrub = 0; 382 383 sync_error_list(spa, &scrub, &spa->spa_errlog_last, tx); 384 } 385 386 /* 387 * Sync out any pending scrub errors. 388 */ 389 sync_error_list(spa, &scrub, &spa->spa_errlog_scrub, tx); 390 391 /* 392 * Update the MOS to reflect the new values. 393 */ 394 (void) zap_update(spa->spa_meta_objset, DMU_POOL_DIRECTORY_OBJECT, 395 DMU_POOL_ERRLOG_LAST, sizeof (uint64_t), 1, 396 &spa->spa_errlog_last, tx); 397 (void) zap_update(spa->spa_meta_objset, DMU_POOL_DIRECTORY_OBJECT, 398 DMU_POOL_ERRLOG_SCRUB, sizeof (uint64_t), 1, 399 &spa->spa_errlog_scrub, tx); 400 401 dmu_tx_commit(tx); 402 403 mutex_exit(&spa->spa_errlog_lock); 404 } 405