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, 2014 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_phys 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_phys_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_phys_t *zb) 75 { 76 zb->zb_objset = zfs_strtonum(buf, &buf); 77 ASSERT(*buf == ':'); 78 zb->zb_object = zfs_strtonum(buf + 1, &buf); 79 ASSERT(*buf == ':'); 80 zb->zb_level = (int)zfs_strtonum(buf + 1, &buf); 81 ASSERT(*buf == ':'); 82 zb->zb_blkid = zfs_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, const zbookmark_phys_t *zb) 94 { 95 spa_error_entry_t search; 96 spa_error_entry_t *new; 97 avl_tree_t *tree; 98 avl_index_t where; 99 100 /* 101 * If we are trying to import a pool, ignore any errors, as we won't be 102 * writing to the pool any time soon. 103 */ 104 if (spa_load_state(spa) == SPA_LOAD_TRYIMPORT) 105 return; 106 107 mutex_enter(&spa->spa_errlist_lock); 108 109 /* 110 * If we have had a request to rotate the log, log it to the next list 111 * instead of the current one. 112 */ 113 if (spa->spa_scrub_active || spa->spa_scrub_finished) 114 tree = &spa->spa_errlist_scrub; 115 else 116 tree = &spa->spa_errlist_last; 117 118 search.se_bookmark = *zb; 119 if (avl_find(tree, &search, &where) != NULL) { 120 mutex_exit(&spa->spa_errlist_lock); 121 return; 122 } 123 124 new = kmem_zalloc(sizeof (spa_error_entry_t), KM_SLEEP); 125 new->se_bookmark = *zb; 126 avl_insert(tree, new, where); 127 128 mutex_exit(&spa->spa_errlist_lock); 129 } 130 131 /* 132 * Return the number of errors currently in the error log. This is actually the 133 * sum of both the last log and the current log, since we don't know the union 134 * of these logs until we reach userland. 135 */ 136 uint64_t 137 spa_get_errlog_size(spa_t *spa) 138 { 139 uint64_t total = 0, count; 140 141 mutex_enter(&spa->spa_errlog_lock); 142 if (spa->spa_errlog_scrub != 0 && 143 zap_count(spa->spa_meta_objset, spa->spa_errlog_scrub, 144 &count) == 0) 145 total += count; 146 147 if (spa->spa_errlog_last != 0 && !spa->spa_scrub_finished && 148 zap_count(spa->spa_meta_objset, spa->spa_errlog_last, 149 &count) == 0) 150 total += count; 151 mutex_exit(&spa->spa_errlog_lock); 152 153 mutex_enter(&spa->spa_errlist_lock); 154 total += avl_numnodes(&spa->spa_errlist_last); 155 total += avl_numnodes(&spa->spa_errlist_scrub); 156 mutex_exit(&spa->spa_errlist_lock); 157 158 return (total); 159 } 160 161 #ifdef _KERNEL 162 static int 163 process_error_log(spa_t *spa, uint64_t obj, void *addr, size_t *count) 164 { 165 zap_cursor_t zc; 166 zap_attribute_t za; 167 zbookmark_phys_t zb; 168 169 if (obj == 0) 170 return (0); 171 172 for (zap_cursor_init(&zc, spa->spa_meta_objset, obj); 173 zap_cursor_retrieve(&zc, &za) == 0; 174 zap_cursor_advance(&zc)) { 175 176 if (*count == 0) { 177 zap_cursor_fini(&zc); 178 return (SET_ERROR(ENOMEM)); 179 } 180 181 name_to_bookmark(za.za_name, &zb); 182 183 if (copyout(&zb, (char *)addr + 184 (*count - 1) * sizeof (zbookmark_phys_t), 185 sizeof (zbookmark_phys_t)) != 0) { 186 zap_cursor_fini(&zc); 187 return (SET_ERROR(EFAULT)); 188 } 189 190 *count -= 1; 191 } 192 193 zap_cursor_fini(&zc); 194 195 return (0); 196 } 197 198 static int 199 process_error_list(avl_tree_t *list, void *addr, size_t *count) 200 { 201 spa_error_entry_t *se; 202 203 for (se = avl_first(list); se != NULL; se = AVL_NEXT(list, se)) { 204 205 if (*count == 0) 206 return (SET_ERROR(ENOMEM)); 207 208 if (copyout(&se->se_bookmark, (char *)addr + 209 (*count - 1) * sizeof (zbookmark_phys_t), 210 sizeof (zbookmark_phys_t)) != 0) 211 return (SET_ERROR(EFAULT)); 212 213 *count -= 1; 214 } 215 216 return (0); 217 } 218 #endif 219 220 /* 221 * Copy all known errors to userland as an array of bookmarks. This is 222 * actually a union of the on-disk last log and current log, as well as any 223 * pending error requests. 224 * 225 * Because the act of reading the on-disk log could cause errors to be 226 * generated, we have two separate locks: one for the error log and one for the 227 * in-core error lists. We only need the error list lock to log and error, so 228 * we grab the error log lock while we read the on-disk logs, and only pick up 229 * the error list lock when we are finished. 230 */ 231 int 232 spa_get_errlog(spa_t *spa, void *uaddr, size_t *count) 233 { 234 int ret = 0; 235 236 #ifdef _KERNEL 237 mutex_enter(&spa->spa_errlog_lock); 238 239 ret = process_error_log(spa, spa->spa_errlog_scrub, uaddr, count); 240 241 if (!ret && !spa->spa_scrub_finished) 242 ret = process_error_log(spa, spa->spa_errlog_last, uaddr, 243 count); 244 245 mutex_enter(&spa->spa_errlist_lock); 246 if (!ret) 247 ret = process_error_list(&spa->spa_errlist_scrub, uaddr, 248 count); 249 if (!ret) 250 ret = process_error_list(&spa->spa_errlist_last, uaddr, 251 count); 252 mutex_exit(&spa->spa_errlist_lock); 253 254 mutex_exit(&spa->spa_errlog_lock); 255 #endif 256 257 return (ret); 258 } 259 260 /* 261 * Called when a scrub completes. This simply set a bit which tells which AVL 262 * tree to add new errors. spa_errlog_sync() is responsible for actually 263 * syncing the changes to the underlying objects. 264 */ 265 void 266 spa_errlog_rotate(spa_t *spa) 267 { 268 mutex_enter(&spa->spa_errlist_lock); 269 spa->spa_scrub_finished = B_TRUE; 270 mutex_exit(&spa->spa_errlist_lock); 271 } 272 273 /* 274 * Discard any pending errors from the spa_t. Called when unloading a faulted 275 * pool, as the errors encountered during the open cannot be synced to disk. 276 */ 277 void 278 spa_errlog_drain(spa_t *spa) 279 { 280 spa_error_entry_t *se; 281 void *cookie; 282 283 mutex_enter(&spa->spa_errlist_lock); 284 285 cookie = NULL; 286 while ((se = avl_destroy_nodes(&spa->spa_errlist_last, 287 &cookie)) != NULL) 288 kmem_free(se, sizeof (spa_error_entry_t)); 289 cookie = NULL; 290 while ((se = avl_destroy_nodes(&spa->spa_errlist_scrub, 291 &cookie)) != NULL) 292 kmem_free(se, sizeof (spa_error_entry_t)); 293 294 mutex_exit(&spa->spa_errlist_lock); 295 } 296 297 /* 298 * Process a list of errors into the current on-disk log. 299 */ 300 static void 301 sync_error_list(spa_t *spa, avl_tree_t *t, uint64_t *obj, dmu_tx_t *tx) 302 { 303 spa_error_entry_t *se; 304 char buf[64]; 305 void *cookie; 306 307 if (avl_numnodes(t) != 0) { 308 /* create log if necessary */ 309 if (*obj == 0) 310 *obj = zap_create(spa->spa_meta_objset, 311 DMU_OT_ERROR_LOG, DMU_OT_NONE, 312 0, tx); 313 314 /* add errors to the current log */ 315 for (se = avl_first(t); se != NULL; se = AVL_NEXT(t, se)) { 316 char *name = se->se_name ? se->se_name : ""; 317 318 bookmark_to_name(&se->se_bookmark, buf, sizeof (buf)); 319 320 (void) zap_update(spa->spa_meta_objset, 321 *obj, buf, 1, strlen(name) + 1, name, tx); 322 } 323 324 /* purge the error list */ 325 cookie = NULL; 326 while ((se = avl_destroy_nodes(t, &cookie)) != NULL) 327 kmem_free(se, sizeof (spa_error_entry_t)); 328 } 329 } 330 331 /* 332 * Sync the error log out to disk. This is a little tricky because the act of 333 * writing the error log requires the spa_errlist_lock. So, we need to lock the 334 * error lists, take a copy of the lists, and then reinitialize them. Then, we 335 * drop the error list lock and take the error log lock, at which point we 336 * do the errlog processing. Then, if we encounter an I/O error during this 337 * process, we can successfully add the error to the list. Note that this will 338 * result in the perpetual recycling of errors, but it is an unlikely situation 339 * and not a performance critical operation. 340 */ 341 void 342 spa_errlog_sync(spa_t *spa, uint64_t txg) 343 { 344 dmu_tx_t *tx; 345 avl_tree_t scrub, last; 346 int scrub_finished; 347 348 mutex_enter(&spa->spa_errlist_lock); 349 350 /* 351 * Bail out early under normal circumstances. 352 */ 353 if (avl_numnodes(&spa->spa_errlist_scrub) == 0 && 354 avl_numnodes(&spa->spa_errlist_last) == 0 && 355 !spa->spa_scrub_finished) { 356 mutex_exit(&spa->spa_errlist_lock); 357 return; 358 } 359 360 spa_get_errlists(spa, &last, &scrub); 361 scrub_finished = spa->spa_scrub_finished; 362 spa->spa_scrub_finished = B_FALSE; 363 364 mutex_exit(&spa->spa_errlist_lock); 365 mutex_enter(&spa->spa_errlog_lock); 366 367 tx = dmu_tx_create_assigned(spa->spa_dsl_pool, txg); 368 369 /* 370 * Sync out the current list of errors. 371 */ 372 sync_error_list(spa, &last, &spa->spa_errlog_last, tx); 373 374 /* 375 * Rotate the log if necessary. 376 */ 377 if (scrub_finished) { 378 if (spa->spa_errlog_last != 0) 379 VERIFY(dmu_object_free(spa->spa_meta_objset, 380 spa->spa_errlog_last, tx) == 0); 381 spa->spa_errlog_last = spa->spa_errlog_scrub; 382 spa->spa_errlog_scrub = 0; 383 384 sync_error_list(spa, &scrub, &spa->spa_errlog_last, tx); 385 } 386 387 /* 388 * Sync out any pending scrub errors. 389 */ 390 sync_error_list(spa, &scrub, &spa->spa_errlog_scrub, tx); 391 392 /* 393 * Update the MOS to reflect the new values. 394 */ 395 (void) zap_update(spa->spa_meta_objset, DMU_POOL_DIRECTORY_OBJECT, 396 DMU_POOL_ERRLOG_LAST, sizeof (uint64_t), 1, 397 &spa->spa_errlog_last, tx); 398 (void) zap_update(spa->spa_meta_objset, DMU_POOL_DIRECTORY_OBJECT, 399 DMU_POOL_ERRLOG_SCRUB, sizeof (uint64_t), 1, 400 &spa->spa_errlog_scrub, tx); 401 402 dmu_tx_commit(tx); 403 404 mutex_exit(&spa->spa_errlog_lock); 405 } 406