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spa_errlog.c (185029) spa_errlog.c (209962)
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/*
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 2008 Sun Microsystems, Inc. All rights reserved.
22 * Copyright 2009 Sun Microsystems, Inc. All rights reserved.
23 * Use is subject to license terms.
24 */
25
23 * Use is subject to license terms.
24 */
25
26#pragma ident "%Z%%M% %I% %E% SMI"
27
28/*
29 * Routines to manage the on-disk persistent error log.
30 *
31 * Each pool stores a log of all logical data errors seen during normal
32 * operation. This is actually the union of two distinct logs: the last log,
33 * and the current log. All errors seen are logged to the current log. When a
34 * scrub completes, the current log becomes the last log, the last log is thrown
35 * out, and the current log is reinitialized. This way, if an error is somehow
36 * corrected, a new scrub will show that that it no longer exists, and will be
37 * deleted from the log when the scrub completes.
38 *
39 * The log is stored using a ZAP object whose key is a string form of the
40 * zbookmark tuple (objset, object, level, blkid), and whose contents is an
41 * optional 'objset:object' human-readable string describing the data. When an
42 * error is first logged, this string will be empty, indicating that no name is
43 * known. This prevents us from having to issue a potentially large amount of
44 * I/O to discover the object name during an error path. Instead, we do the
45 * calculation when the data is requested, storing the result so future queries
46 * will be faster.
47 *
48 * This log is then shipped into an nvlist where the key is the dataset name and
49 * the value is the object name. Userland is then responsible for uniquifying
50 * this list and displaying it to the user.
51 */
52
53#include <sys/dmu_tx.h>
54#include <sys/spa.h>
55#include <sys/spa_impl.h>
56#include <sys/zap.h>
57#include <sys/zio.h>
58
59/*
60 * This is a stripped-down version of strtoull, suitable only for converting
61 * lowercase hexidecimal numbers that don't overflow.
62 */
63#ifdef _KERNEL
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 * This is a stripped-down version of strtoull, suitable only for converting
59 * lowercase hexidecimal numbers that don't overflow.
60 */
61#ifdef _KERNEL
64static uint64_t
65_strtonum(char *str, char **nptr)
62uint64_t
63_strtonum(const char *str, char **nptr)
66{
67 uint64_t val = 0;
68 char c;
69 int digit;
70
71 while ((c = *str) != '\0') {
72 if (c >= '0' && c <= '9')
73 digit = c - '0';
74 else if (c >= 'a' && c <= 'f')
75 digit = 10 + c - 'a';
76 else
77 break;
78
79 val *= 16;
80 val += digit;
81
82 str++;
83 }
84
64{
65 uint64_t val = 0;
66 char c;
67 int digit;
68
69 while ((c = *str) != '\0') {
70 if (c >= '0' && c <= '9')
71 digit = c - '0';
72 else if (c >= 'a' && c <= 'f')
73 digit = 10 + c - 'a';
74 else
75 break;
76
77 val *= 16;
78 val += digit;
79
80 str++;
81 }
82
85 *nptr = str;
83 if (nptr)
84 *nptr = (char *)str;
86
87 return (val);
88}
89#endif
90
91/*
92 * Convert a bookmark to a string.
93 */
94static void
95bookmark_to_name(zbookmark_t *zb, char *buf, size_t len)
96{
97 (void) snprintf(buf, len, "%llx:%llx:%llx:%llx",
98 (u_longlong_t)zb->zb_objset, (u_longlong_t)zb->zb_object,
99 (u_longlong_t)zb->zb_level, (u_longlong_t)zb->zb_blkid);
100}
101
102/*
103 * Convert a string to a bookmark
104 */
105#ifdef _KERNEL
106static void
107name_to_bookmark(char *buf, zbookmark_t *zb)
108{
109 zb->zb_objset = _strtonum(buf, &buf);
110 ASSERT(*buf == ':');
111 zb->zb_object = _strtonum(buf + 1, &buf);
112 ASSERT(*buf == ':');
113 zb->zb_level = (int)_strtonum(buf + 1, &buf);
114 ASSERT(*buf == ':');
115 zb->zb_blkid = _strtonum(buf + 1, &buf);
116 ASSERT(*buf == '\0');
117}
118#endif
119
120/*
121 * Log an uncorrectable error to the persistent error log. We add it to the
122 * spa's list of pending errors. The changes are actually synced out to disk
123 * during spa_errlog_sync().
124 */
125void
126spa_log_error(spa_t *spa, zio_t *zio)
127{
128 zbookmark_t *zb = &zio->io_logical->io_bookmark;
129 spa_error_entry_t search;
130 spa_error_entry_t *new;
131 avl_tree_t *tree;
132 avl_index_t where;
133
134 /*
135 * If we are trying to import a pool, ignore any errors, as we won't be
136 * writing to the pool any time soon.
137 */
138 if (spa->spa_load_state == SPA_LOAD_TRYIMPORT)
139 return;
140
141 mutex_enter(&spa->spa_errlist_lock);
142
143 /*
144 * If we have had a request to rotate the log, log it to the next list
145 * instead of the current one.
146 */
147 if (spa->spa_scrub_active || spa->spa_scrub_finished)
148 tree = &spa->spa_errlist_scrub;
149 else
150 tree = &spa->spa_errlist_last;
151
152 search.se_bookmark = *zb;
153 if (avl_find(tree, &search, &where) != NULL) {
154 mutex_exit(&spa->spa_errlist_lock);
155 return;
156 }
157
158 new = kmem_zalloc(sizeof (spa_error_entry_t), KM_SLEEP);
159 new->se_bookmark = *zb;
160 avl_insert(tree, new, where);
161
162 mutex_exit(&spa->spa_errlist_lock);
163}
164
165/*
166 * Return the number of errors currently in the error log. This is actually the
167 * sum of both the last log and the current log, since we don't know the union
168 * of these logs until we reach userland.
169 */
170uint64_t
171spa_get_errlog_size(spa_t *spa)
172{
173 uint64_t total = 0, count;
174
175 mutex_enter(&spa->spa_errlog_lock);
176 if (spa->spa_errlog_scrub != 0 &&
177 zap_count(spa->spa_meta_objset, spa->spa_errlog_scrub,
178 &count) == 0)
179 total += count;
180
181 if (spa->spa_errlog_last != 0 && !spa->spa_scrub_finished &&
182 zap_count(spa->spa_meta_objset, spa->spa_errlog_last,
183 &count) == 0)
184 total += count;
185 mutex_exit(&spa->spa_errlog_lock);
186
187 mutex_enter(&spa->spa_errlist_lock);
188 total += avl_numnodes(&spa->spa_errlist_last);
189 total += avl_numnodes(&spa->spa_errlist_scrub);
190 mutex_exit(&spa->spa_errlist_lock);
191
192 return (total);
193}
194
195#ifdef _KERNEL
196static int
197process_error_log(spa_t *spa, uint64_t obj, void *addr, size_t *count)
198{
199 zap_cursor_t zc;
200 zap_attribute_t za;
201 zbookmark_t zb;
202
203 if (obj == 0)
204 return (0);
205
206 for (zap_cursor_init(&zc, spa->spa_meta_objset, obj);
207 zap_cursor_retrieve(&zc, &za) == 0;
208 zap_cursor_advance(&zc)) {
209
210 if (*count == 0) {
211 zap_cursor_fini(&zc);
212 return (ENOMEM);
213 }
214
215 name_to_bookmark(za.za_name, &zb);
216
217 if (copyout(&zb, (char *)addr +
218 (*count - 1) * sizeof (zbookmark_t),
219 sizeof (zbookmark_t)) != 0)
220 return (EFAULT);
221
222 *count -= 1;
223 }
224
225 zap_cursor_fini(&zc);
226
227 return (0);
228}
229
230static int
231process_error_list(avl_tree_t *list, void *addr, size_t *count)
232{
233 spa_error_entry_t *se;
234
235 for (se = avl_first(list); se != NULL; se = AVL_NEXT(list, se)) {
236
237 if (*count == 0)
238 return (ENOMEM);
239
240 if (copyout(&se->se_bookmark, (char *)addr +
241 (*count - 1) * sizeof (zbookmark_t),
242 sizeof (zbookmark_t)) != 0)
243 return (EFAULT);
244
245 *count -= 1;
246 }
247
248 return (0);
249}
250#endif
251
252/*
253 * Copy all known errors to userland as an array of bookmarks. This is
254 * actually a union of the on-disk last log and current log, as well as any
255 * pending error requests.
256 *
257 * Because the act of reading the on-disk log could cause errors to be
258 * generated, we have two separate locks: one for the error log and one for the
259 * in-core error lists. We only need the error list lock to log and error, so
260 * we grab the error log lock while we read the on-disk logs, and only pick up
261 * the error list lock when we are finished.
262 */
263int
264spa_get_errlog(spa_t *spa, void *uaddr, size_t *count)
265{
266 int ret = 0;
267
268#ifdef _KERNEL
269 mutex_enter(&spa->spa_errlog_lock);
270
271 ret = process_error_log(spa, spa->spa_errlog_scrub, uaddr, count);
272
273 if (!ret && !spa->spa_scrub_finished)
274 ret = process_error_log(spa, spa->spa_errlog_last, uaddr,
275 count);
276
277 mutex_enter(&spa->spa_errlist_lock);
278 if (!ret)
279 ret = process_error_list(&spa->spa_errlist_scrub, uaddr,
280 count);
281 if (!ret)
282 ret = process_error_list(&spa->spa_errlist_last, uaddr,
283 count);
284 mutex_exit(&spa->spa_errlist_lock);
285
286 mutex_exit(&spa->spa_errlog_lock);
287#endif
288
289 return (ret);
290}
291
292/*
293 * Called when a scrub completes. This simply set a bit which tells which AVL
294 * tree to add new errors. spa_errlog_sync() is responsible for actually
295 * syncing the changes to the underlying objects.
296 */
297void
298spa_errlog_rotate(spa_t *spa)
299{
300 mutex_enter(&spa->spa_errlist_lock);
301 spa->spa_scrub_finished = B_TRUE;
302 mutex_exit(&spa->spa_errlist_lock);
303}
304
305/*
306 * Discard any pending errors from the spa_t. Called when unloading a faulted
307 * pool, as the errors encountered during the open cannot be synced to disk.
308 */
309void
310spa_errlog_drain(spa_t *spa)
311{
312 spa_error_entry_t *se;
313 void *cookie;
314
315 mutex_enter(&spa->spa_errlist_lock);
316
317 cookie = NULL;
318 while ((se = avl_destroy_nodes(&spa->spa_errlist_last,
319 &cookie)) != NULL)
320 kmem_free(se, sizeof (spa_error_entry_t));
321 cookie = NULL;
322 while ((se = avl_destroy_nodes(&spa->spa_errlist_scrub,
323 &cookie)) != NULL)
324 kmem_free(se, sizeof (spa_error_entry_t));
325
326 mutex_exit(&spa->spa_errlist_lock);
327}
328
329/*
330 * Process a list of errors into the current on-disk log.
331 */
332static void
333sync_error_list(spa_t *spa, avl_tree_t *t, uint64_t *obj, dmu_tx_t *tx)
334{
335 spa_error_entry_t *se;
336 char buf[64];
337 void *cookie;
338
339 if (avl_numnodes(t) != 0) {
340 /* create log if necessary */
341 if (*obj == 0)
342 *obj = zap_create(spa->spa_meta_objset,
343 DMU_OT_ERROR_LOG, DMU_OT_NONE,
344 0, tx);
345
346 /* add errors to the current log */
347 for (se = avl_first(t); se != NULL; se = AVL_NEXT(t, se)) {
348 char *name = se->se_name ? se->se_name : "";
349
350 bookmark_to_name(&se->se_bookmark, buf, sizeof (buf));
351
352 (void) zap_update(spa->spa_meta_objset,
353 *obj, buf, 1, strlen(name) + 1, name, tx);
354 }
355
356 /* purge the error list */
357 cookie = NULL;
358 while ((se = avl_destroy_nodes(t, &cookie)) != NULL)
359 kmem_free(se, sizeof (spa_error_entry_t));
360 }
361}
362
363/*
364 * Sync the error log out to disk. This is a little tricky because the act of
365 * writing the error log requires the spa_errlist_lock. So, we need to lock the
366 * error lists, take a copy of the lists, and then reinitialize them. Then, we
367 * drop the error list lock and take the error log lock, at which point we
368 * do the errlog processing. Then, if we encounter an I/O error during this
369 * process, we can successfully add the error to the list. Note that this will
370 * result in the perpetual recycling of errors, but it is an unlikely situation
371 * and not a performance critical operation.
372 */
373void
374spa_errlog_sync(spa_t *spa, uint64_t txg)
375{
376 dmu_tx_t *tx;
377 avl_tree_t scrub, last;
378 int scrub_finished;
379
380 mutex_enter(&spa->spa_errlist_lock);
381
382 /*
383 * Bail out early under normal circumstances.
384 */
385 if (avl_numnodes(&spa->spa_errlist_scrub) == 0 &&
386 avl_numnodes(&spa->spa_errlist_last) == 0 &&
387 !spa->spa_scrub_finished) {
388 mutex_exit(&spa->spa_errlist_lock);
389 return;
390 }
391
392 spa_get_errlists(spa, &last, &scrub);
393 scrub_finished = spa->spa_scrub_finished;
394 spa->spa_scrub_finished = B_FALSE;
395
396 mutex_exit(&spa->spa_errlist_lock);
397 mutex_enter(&spa->spa_errlog_lock);
398
399 tx = dmu_tx_create_assigned(spa->spa_dsl_pool, txg);
400
401 /*
402 * Sync out the current list of errors.
403 */
404 sync_error_list(spa, &last, &spa->spa_errlog_last, tx);
405
406 /*
407 * Rotate the log if necessary.
408 */
409 if (scrub_finished) {
410 if (spa->spa_errlog_last != 0)
411 VERIFY(dmu_object_free(spa->spa_meta_objset,
412 spa->spa_errlog_last, tx) == 0);
413 spa->spa_errlog_last = spa->spa_errlog_scrub;
414 spa->spa_errlog_scrub = 0;
415
416 sync_error_list(spa, &scrub, &spa->spa_errlog_last, tx);
417 }
418
419 /*
420 * Sync out any pending scrub errors.
421 */
422 sync_error_list(spa, &scrub, &spa->spa_errlog_scrub, tx);
423
424 /*
425 * Update the MOS to reflect the new values.
426 */
427 (void) zap_update(spa->spa_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
428 DMU_POOL_ERRLOG_LAST, sizeof (uint64_t), 1,
429 &spa->spa_errlog_last, tx);
430 (void) zap_update(spa->spa_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
431 DMU_POOL_ERRLOG_SCRUB, sizeof (uint64_t), 1,
432 &spa->spa_errlog_scrub, tx);
433
434 dmu_tx_commit(tx);
435
436 mutex_exit(&spa->spa_errlog_lock);
437}
85
86 return (val);
87}
88#endif
89
90/*
91 * Convert a bookmark to a string.
92 */
93static void
94bookmark_to_name(zbookmark_t *zb, char *buf, size_t len)
95{
96 (void) snprintf(buf, len, "%llx:%llx:%llx:%llx",
97 (u_longlong_t)zb->zb_objset, (u_longlong_t)zb->zb_object,
98 (u_longlong_t)zb->zb_level, (u_longlong_t)zb->zb_blkid);
99}
100
101/*
102 * Convert a string to a bookmark
103 */
104#ifdef _KERNEL
105static void
106name_to_bookmark(char *buf, zbookmark_t *zb)
107{
108 zb->zb_objset = _strtonum(buf, &buf);
109 ASSERT(*buf == ':');
110 zb->zb_object = _strtonum(buf + 1, &buf);
111 ASSERT(*buf == ':');
112 zb->zb_level = (int)_strtonum(buf + 1, &buf);
113 ASSERT(*buf == ':');
114 zb->zb_blkid = _strtonum(buf + 1, &buf);
115 ASSERT(*buf == '\0');
116}
117#endif
118
119/*
120 * Log an uncorrectable error to the persistent error log. We add it to the
121 * spa's list of pending errors. The changes are actually synced out to disk
122 * during spa_errlog_sync().
123 */
124void
125spa_log_error(spa_t *spa, zio_t *zio)
126{
127 zbookmark_t *zb = &zio->io_logical->io_bookmark;
128 spa_error_entry_t search;
129 spa_error_entry_t *new;
130 avl_tree_t *tree;
131 avl_index_t where;
132
133 /*
134 * If we are trying to import a pool, ignore any errors, as we won't be
135 * writing to the pool any time soon.
136 */
137 if (spa->spa_load_state == SPA_LOAD_TRYIMPORT)
138 return;
139
140 mutex_enter(&spa->spa_errlist_lock);
141
142 /*
143 * If we have had a request to rotate the log, log it to the next list
144 * instead of the current one.
145 */
146 if (spa->spa_scrub_active || spa->spa_scrub_finished)
147 tree = &spa->spa_errlist_scrub;
148 else
149 tree = &spa->spa_errlist_last;
150
151 search.se_bookmark = *zb;
152 if (avl_find(tree, &search, &where) != NULL) {
153 mutex_exit(&spa->spa_errlist_lock);
154 return;
155 }
156
157 new = kmem_zalloc(sizeof (spa_error_entry_t), KM_SLEEP);
158 new->se_bookmark = *zb;
159 avl_insert(tree, new, where);
160
161 mutex_exit(&spa->spa_errlist_lock);
162}
163
164/*
165 * Return the number of errors currently in the error log. This is actually the
166 * sum of both the last log and the current log, since we don't know the union
167 * of these logs until we reach userland.
168 */
169uint64_t
170spa_get_errlog_size(spa_t *spa)
171{
172 uint64_t total = 0, count;
173
174 mutex_enter(&spa->spa_errlog_lock);
175 if (spa->spa_errlog_scrub != 0 &&
176 zap_count(spa->spa_meta_objset, spa->spa_errlog_scrub,
177 &count) == 0)
178 total += count;
179
180 if (spa->spa_errlog_last != 0 && !spa->spa_scrub_finished &&
181 zap_count(spa->spa_meta_objset, spa->spa_errlog_last,
182 &count) == 0)
183 total += count;
184 mutex_exit(&spa->spa_errlog_lock);
185
186 mutex_enter(&spa->spa_errlist_lock);
187 total += avl_numnodes(&spa->spa_errlist_last);
188 total += avl_numnodes(&spa->spa_errlist_scrub);
189 mutex_exit(&spa->spa_errlist_lock);
190
191 return (total);
192}
193
194#ifdef _KERNEL
195static int
196process_error_log(spa_t *spa, uint64_t obj, void *addr, size_t *count)
197{
198 zap_cursor_t zc;
199 zap_attribute_t za;
200 zbookmark_t zb;
201
202 if (obj == 0)
203 return (0);
204
205 for (zap_cursor_init(&zc, spa->spa_meta_objset, obj);
206 zap_cursor_retrieve(&zc, &za) == 0;
207 zap_cursor_advance(&zc)) {
208
209 if (*count == 0) {
210 zap_cursor_fini(&zc);
211 return (ENOMEM);
212 }
213
214 name_to_bookmark(za.za_name, &zb);
215
216 if (copyout(&zb, (char *)addr +
217 (*count - 1) * sizeof (zbookmark_t),
218 sizeof (zbookmark_t)) != 0)
219 return (EFAULT);
220
221 *count -= 1;
222 }
223
224 zap_cursor_fini(&zc);
225
226 return (0);
227}
228
229static int
230process_error_list(avl_tree_t *list, void *addr, size_t *count)
231{
232 spa_error_entry_t *se;
233
234 for (se = avl_first(list); se != NULL; se = AVL_NEXT(list, se)) {
235
236 if (*count == 0)
237 return (ENOMEM);
238
239 if (copyout(&se->se_bookmark, (char *)addr +
240 (*count - 1) * sizeof (zbookmark_t),
241 sizeof (zbookmark_t)) != 0)
242 return (EFAULT);
243
244 *count -= 1;
245 }
246
247 return (0);
248}
249#endif
250
251/*
252 * Copy all known errors to userland as an array of bookmarks. This is
253 * actually a union of the on-disk last log and current log, as well as any
254 * pending error requests.
255 *
256 * Because the act of reading the on-disk log could cause errors to be
257 * generated, we have two separate locks: one for the error log and one for the
258 * in-core error lists. We only need the error list lock to log and error, so
259 * we grab the error log lock while we read the on-disk logs, and only pick up
260 * the error list lock when we are finished.
261 */
262int
263spa_get_errlog(spa_t *spa, void *uaddr, size_t *count)
264{
265 int ret = 0;
266
267#ifdef _KERNEL
268 mutex_enter(&spa->spa_errlog_lock);
269
270 ret = process_error_log(spa, spa->spa_errlog_scrub, uaddr, count);
271
272 if (!ret && !spa->spa_scrub_finished)
273 ret = process_error_log(spa, spa->spa_errlog_last, uaddr,
274 count);
275
276 mutex_enter(&spa->spa_errlist_lock);
277 if (!ret)
278 ret = process_error_list(&spa->spa_errlist_scrub, uaddr,
279 count);
280 if (!ret)
281 ret = process_error_list(&spa->spa_errlist_last, uaddr,
282 count);
283 mutex_exit(&spa->spa_errlist_lock);
284
285 mutex_exit(&spa->spa_errlog_lock);
286#endif
287
288 return (ret);
289}
290
291/*
292 * Called when a scrub completes. This simply set a bit which tells which AVL
293 * tree to add new errors. spa_errlog_sync() is responsible for actually
294 * syncing the changes to the underlying objects.
295 */
296void
297spa_errlog_rotate(spa_t *spa)
298{
299 mutex_enter(&spa->spa_errlist_lock);
300 spa->spa_scrub_finished = B_TRUE;
301 mutex_exit(&spa->spa_errlist_lock);
302}
303
304/*
305 * Discard any pending errors from the spa_t. Called when unloading a faulted
306 * pool, as the errors encountered during the open cannot be synced to disk.
307 */
308void
309spa_errlog_drain(spa_t *spa)
310{
311 spa_error_entry_t *se;
312 void *cookie;
313
314 mutex_enter(&spa->spa_errlist_lock);
315
316 cookie = NULL;
317 while ((se = avl_destroy_nodes(&spa->spa_errlist_last,
318 &cookie)) != NULL)
319 kmem_free(se, sizeof (spa_error_entry_t));
320 cookie = NULL;
321 while ((se = avl_destroy_nodes(&spa->spa_errlist_scrub,
322 &cookie)) != NULL)
323 kmem_free(se, sizeof (spa_error_entry_t));
324
325 mutex_exit(&spa->spa_errlist_lock);
326}
327
328/*
329 * Process a list of errors into the current on-disk log.
330 */
331static void
332sync_error_list(spa_t *spa, avl_tree_t *t, uint64_t *obj, dmu_tx_t *tx)
333{
334 spa_error_entry_t *se;
335 char buf[64];
336 void *cookie;
337
338 if (avl_numnodes(t) != 0) {
339 /* create log if necessary */
340 if (*obj == 0)
341 *obj = zap_create(spa->spa_meta_objset,
342 DMU_OT_ERROR_LOG, DMU_OT_NONE,
343 0, tx);
344
345 /* add errors to the current log */
346 for (se = avl_first(t); se != NULL; se = AVL_NEXT(t, se)) {
347 char *name = se->se_name ? se->se_name : "";
348
349 bookmark_to_name(&se->se_bookmark, buf, sizeof (buf));
350
351 (void) zap_update(spa->spa_meta_objset,
352 *obj, buf, 1, strlen(name) + 1, name, tx);
353 }
354
355 /* purge the error list */
356 cookie = NULL;
357 while ((se = avl_destroy_nodes(t, &cookie)) != NULL)
358 kmem_free(se, sizeof (spa_error_entry_t));
359 }
360}
361
362/*
363 * Sync the error log out to disk. This is a little tricky because the act of
364 * writing the error log requires the spa_errlist_lock. So, we need to lock the
365 * error lists, take a copy of the lists, and then reinitialize them. Then, we
366 * drop the error list lock and take the error log lock, at which point we
367 * do the errlog processing. Then, if we encounter an I/O error during this
368 * process, we can successfully add the error to the list. Note that this will
369 * result in the perpetual recycling of errors, but it is an unlikely situation
370 * and not a performance critical operation.
371 */
372void
373spa_errlog_sync(spa_t *spa, uint64_t txg)
374{
375 dmu_tx_t *tx;
376 avl_tree_t scrub, last;
377 int scrub_finished;
378
379 mutex_enter(&spa->spa_errlist_lock);
380
381 /*
382 * Bail out early under normal circumstances.
383 */
384 if (avl_numnodes(&spa->spa_errlist_scrub) == 0 &&
385 avl_numnodes(&spa->spa_errlist_last) == 0 &&
386 !spa->spa_scrub_finished) {
387 mutex_exit(&spa->spa_errlist_lock);
388 return;
389 }
390
391 spa_get_errlists(spa, &last, &scrub);
392 scrub_finished = spa->spa_scrub_finished;
393 spa->spa_scrub_finished = B_FALSE;
394
395 mutex_exit(&spa->spa_errlist_lock);
396 mutex_enter(&spa->spa_errlog_lock);
397
398 tx = dmu_tx_create_assigned(spa->spa_dsl_pool, txg);
399
400 /*
401 * Sync out the current list of errors.
402 */
403 sync_error_list(spa, &last, &spa->spa_errlog_last, tx);
404
405 /*
406 * Rotate the log if necessary.
407 */
408 if (scrub_finished) {
409 if (spa->spa_errlog_last != 0)
410 VERIFY(dmu_object_free(spa->spa_meta_objset,
411 spa->spa_errlog_last, tx) == 0);
412 spa->spa_errlog_last = spa->spa_errlog_scrub;
413 spa->spa_errlog_scrub = 0;
414
415 sync_error_list(spa, &scrub, &spa->spa_errlog_last, tx);
416 }
417
418 /*
419 * Sync out any pending scrub errors.
420 */
421 sync_error_list(spa, &scrub, &spa->spa_errlog_scrub, tx);
422
423 /*
424 * Update the MOS to reflect the new values.
425 */
426 (void) zap_update(spa->spa_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
427 DMU_POOL_ERRLOG_LAST, sizeof (uint64_t), 1,
428 &spa->spa_errlog_last, tx);
429 (void) zap_update(spa->spa_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
430 DMU_POOL_ERRLOG_SCRUB, sizeof (uint64_t), 1,
431 &spa->spa_errlog_scrub, tx);
432
433 dmu_tx_commit(tx);
434
435 mutex_exit(&spa->spa_errlog_lock);
436}