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 zap_cursor_fini(&zc); 188 return (SET_ERROR(EFAULT)); 189 } 190 191 *count -= 1; 192 } 193 194 zap_cursor_fini(&zc); 195 196 return (0); 197 } 198 199 static int 200 process_error_list(avl_tree_t *list, void *addr, size_t *count) 201 { 202 spa_error_entry_t *se; 203 204 for (se = avl_first(list); se != NULL; se = AVL_NEXT(list, se)) { 205 206 if (*count == 0) 207 return (SET_ERROR(ENOMEM)); 208 209 if (copyout(&se->se_bookmark, (char *)addr + 210 (*count - 1) * sizeof (zbookmark_t), 211 sizeof (zbookmark_t)) != 0) 212 return (SET_ERROR(EFAULT)); 213 214 *count -= 1; 215 } 216 217 return (0); 218 } 219 #endif 220 221 /* 222 * Copy all known errors to userland as an array of bookmarks. This is 223 * actually a union of the on-disk last log and current log, as well as any 224 * pending error requests. 225 * 226 * Because the act of reading the on-disk log could cause errors to be 227 * generated, we have two separate locks: one for the error log and one for the 228 * in-core error lists. We only need the error list lock to log and error, so 229 * we grab the error log lock while we read the on-disk logs, and only pick up 230 * the error list lock when we are finished. 231 */ 232 int 233 spa_get_errlog(spa_t *spa, void *uaddr, size_t *count) 234 { 235 int ret = 0; 236 237 #ifdef _KERNEL 238 mutex_enter(&spa->spa_errlog_lock); 239 240 ret = process_error_log(spa, spa->spa_errlog_scrub, uaddr, count); 241 242 if (!ret && !spa->spa_scrub_finished) 243 ret = process_error_log(spa, spa->spa_errlog_last, uaddr, 244 count); 245 246 mutex_enter(&spa->spa_errlist_lock); 247 if (!ret) 248 ret = process_error_list(&spa->spa_errlist_scrub, uaddr, 249 count); 250 if (!ret) 251 ret = process_error_list(&spa->spa_errlist_last, uaddr, 252 count); 253 mutex_exit(&spa->spa_errlist_lock); 254 255 mutex_exit(&spa->spa_errlog_lock); 256 #endif 257 258 return (ret); 259 } 260 261 /* 262 * Called when a scrub completes. This simply set a bit which tells which AVL 263 * tree to add new errors. spa_errlog_sync() is responsible for actually 264 * syncing the changes to the underlying objects. 265 */ 266 void 267 spa_errlog_rotate(spa_t *spa) 268 { 269 mutex_enter(&spa->spa_errlist_lock); 270 spa->spa_scrub_finished = B_TRUE; 271 mutex_exit(&spa->spa_errlist_lock); 272 } 273 274 /* 275 * Discard any pending errors from the spa_t. Called when unloading a faulted 276 * pool, as the errors encountered during the open cannot be synced to disk. 277 */ 278 void 279 spa_errlog_drain(spa_t *spa) 280 { 281 spa_error_entry_t *se; 282 void *cookie; 283 284 mutex_enter(&spa->spa_errlist_lock); 285 286 cookie = NULL; 287 while ((se = avl_destroy_nodes(&spa->spa_errlist_last, 288 &cookie)) != NULL) 289 kmem_free(se, sizeof (spa_error_entry_t)); 290 cookie = NULL; 291 while ((se = avl_destroy_nodes(&spa->spa_errlist_scrub, 292 &cookie)) != NULL) 293 kmem_free(se, sizeof (spa_error_entry_t)); 294 295 mutex_exit(&spa->spa_errlist_lock); 296 } 297 298 /* 299 * Process a list of errors into the current on-disk log. 300 */ 301 static void 302 sync_error_list(spa_t *spa, avl_tree_t *t, uint64_t *obj, dmu_tx_t *tx) 303 { 304 spa_error_entry_t *se; 305 char buf[64]; 306 void *cookie; 307 308 if (avl_numnodes(t) != 0) { 309 /* create log if necessary */ 310 if (*obj == 0) 311 *obj = zap_create(spa->spa_meta_objset, 312 DMU_OT_ERROR_LOG, DMU_OT_NONE, 313 0, tx); 314 315 /* add errors to the current log */ 316 for (se = avl_first(t); se != NULL; se = AVL_NEXT(t, se)) { 317 char *name = se->se_name ? se->se_name : ""; 318 319 bookmark_to_name(&se->se_bookmark, buf, sizeof (buf)); 320 321 (void) zap_update(spa->spa_meta_objset, 322 *obj, buf, 1, strlen(name) + 1, name, tx); 323 } 324 325 /* purge the error list */ 326 cookie = NULL; 327 while ((se = avl_destroy_nodes(t, &cookie)) != NULL) 328 kmem_free(se, sizeof (spa_error_entry_t)); 329 } 330 } 331 332 /* 333 * Sync the error log out to disk. This is a little tricky because the act of 334 * writing the error log requires the spa_errlist_lock. So, we need to lock the 335 * error lists, take a copy of the lists, and then reinitialize them. Then, we 336 * drop the error list lock and take the error log lock, at which point we 337 * do the errlog processing. Then, if we encounter an I/O error during this 338 * process, we can successfully add the error to the list. Note that this will 339 * result in the perpetual recycling of errors, but it is an unlikely situation 340 * and not a performance critical operation. 341 */ 342 void 343 spa_errlog_sync(spa_t *spa, uint64_t txg) 344 { 345 dmu_tx_t *tx; 346 avl_tree_t scrub, last; 347 int scrub_finished; 348 349 mutex_enter(&spa->spa_errlist_lock); 350 351 /* 352 * Bail out early under normal circumstances. 353 */ 354 if (avl_numnodes(&spa->spa_errlist_scrub) == 0 && 355 avl_numnodes(&spa->spa_errlist_last) == 0 && 356 !spa->spa_scrub_finished) { 357 mutex_exit(&spa->spa_errlist_lock); 358 return; 359 } 360 361 spa_get_errlists(spa, &last, &scrub); 362 scrub_finished = spa->spa_scrub_finished; 363 spa->spa_scrub_finished = B_FALSE; 364 365 mutex_exit(&spa->spa_errlist_lock); 366 mutex_enter(&spa->spa_errlog_lock); 367 368 tx = dmu_tx_create_assigned(spa->spa_dsl_pool, txg); 369 370 /* 371 * Sync out the current list of errors. 372 */ 373 sync_error_list(spa, &last, &spa->spa_errlog_last, tx); 374 375 /* 376 * Rotate the log if necessary. 377 */ 378 if (scrub_finished) { 379 if (spa->spa_errlog_last != 0) 380 VERIFY(dmu_object_free(spa->spa_meta_objset, 381 spa->spa_errlog_last, tx) == 0); 382 spa->spa_errlog_last = spa->spa_errlog_scrub; 383 spa->spa_errlog_scrub = 0; 384 385 sync_error_list(spa, &scrub, &spa->spa_errlog_last, tx); 386 } 387 388 /* 389 * Sync out any pending scrub errors. 390 */ 391 sync_error_list(spa, &scrub, &spa->spa_errlog_scrub, tx); 392 393 /* 394 * Update the MOS to reflect the new values. 395 */ 396 (void) zap_update(spa->spa_meta_objset, DMU_POOL_DIRECTORY_OBJECT, 397 DMU_POOL_ERRLOG_LAST, sizeof (uint64_t), 1, 398 &spa->spa_errlog_last, tx); 399 (void) zap_update(spa->spa_meta_objset, DMU_POOL_DIRECTORY_OBJECT, 400 DMU_POOL_ERRLOG_SCRUB, sizeof (uint64_t), 1, 401 &spa->spa_errlog_scrub, tx); 402 403 dmu_tx_commit(tx); 404 405 mutex_exit(&spa->spa_errlog_lock); 406 } 407