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 2010 Sun Microsystems, Inc. All rights reserved.
23 * Use is subject to license terms.
24 */
25
26 /*
27 * Copyright (c) 2013 by Delphix. All rights reserved.
28 */
29
30 #include <sys/zfs_context.h>
31 #include <sys/spa.h>
32 #include <sys/vdev_impl.h>
33 #include <sys/zio.h>
34 #include <sys/fs/zfs.h>
35
36 /*
37 * Virtual device vector for mirroring.
38 */
39
40 typedef struct mirror_child {
41 vdev_t *mc_vd;
42 uint64_t mc_offset;
43 int mc_error;
44 uint8_t mc_tried;
45 uint8_t mc_skipped;
46 uint8_t mc_speculative;
47 } mirror_child_t;
48
49 typedef struct mirror_map {
50 int mm_children;
51 int mm_replacing;
52 int mm_preferred;
53 int mm_root;
54 mirror_child_t mm_child[1];
55 } mirror_map_t;
56
57 int vdev_mirror_shift = 21;
58
59 static void
vdev_mirror_map_free(zio_t * zio)60 vdev_mirror_map_free(zio_t *zio)
61 {
62 mirror_map_t *mm = zio->io_vsd;
63
64 kmem_free(mm, offsetof(mirror_map_t, mm_child[mm->mm_children]));
65 }
66
67 static const zio_vsd_ops_t vdev_mirror_vsd_ops = {
68 vdev_mirror_map_free,
69 zio_vsd_default_cksum_report
70 };
71
72 static mirror_map_t *
vdev_mirror_map_alloc(zio_t * zio)73 vdev_mirror_map_alloc(zio_t *zio)
74 {
75 mirror_map_t *mm = NULL;
76 mirror_child_t *mc;
77 vdev_t *vd = zio->io_vd;
78 int c, d;
79
80 if (vd == NULL) {
81 dva_t *dva = zio->io_bp->blk_dva;
82 spa_t *spa = zio->io_spa;
83
84 c = BP_GET_NDVAS(zio->io_bp);
85
86 mm = kmem_zalloc(offsetof(mirror_map_t, mm_child[c]), KM_SLEEP);
87 mm->mm_children = c;
88 mm->mm_replacing = B_FALSE;
89 mm->mm_preferred = spa_get_random(c);
90 mm->mm_root = B_TRUE;
91
92 /*
93 * Check the other, lower-index DVAs to see if they're on
94 * the same vdev as the child we picked. If they are, use
95 * them since they are likely to have been allocated from
96 * the primary metaslab in use at the time, and hence are
97 * more likely to have locality with single-copy data.
98 */
99 for (c = mm->mm_preferred, d = c - 1; d >= 0; d--) {
100 if (DVA_GET_VDEV(&dva[d]) == DVA_GET_VDEV(&dva[c]))
101 mm->mm_preferred = d;
102 }
103
104 for (c = 0; c < mm->mm_children; c++) {
105 mc = &mm->mm_child[c];
106
107 mc->mc_vd = vdev_lookup_top(spa, DVA_GET_VDEV(&dva[c]));
108 mc->mc_offset = DVA_GET_OFFSET(&dva[c]);
109 }
110 } else {
111 c = vd->vdev_children;
112
113 mm = kmem_zalloc(offsetof(mirror_map_t, mm_child[c]), KM_SLEEP);
114 mm->mm_children = c;
115 mm->mm_replacing = (vd->vdev_ops == &vdev_replacing_ops ||
116 vd->vdev_ops == &vdev_spare_ops);
117 mm->mm_preferred = mm->mm_replacing ? 0 :
118 (zio->io_offset >> vdev_mirror_shift) % c;
119 mm->mm_root = B_FALSE;
120
121 for (c = 0; c < mm->mm_children; c++) {
122 mc = &mm->mm_child[c];
123 mc->mc_vd = vd->vdev_child[c];
124 mc->mc_offset = zio->io_offset;
125 }
126 }
127
128 zio->io_vsd = mm;
129 zio->io_vsd_ops = &vdev_mirror_vsd_ops;
130 return (mm);
131 }
132
133 static int
vdev_mirror_open(vdev_t * vd,uint64_t * asize,uint64_t * max_asize,uint64_t * logical_ashift,uint64_t * physical_ashift)134 vdev_mirror_open(vdev_t *vd, uint64_t *asize, uint64_t *max_asize,
135 uint64_t *logical_ashift, uint64_t *physical_ashift)
136 {
137 int numerrors = 0;
138 int lasterror = 0;
139
140 if (vd->vdev_children == 0) {
141 vd->vdev_stat.vs_aux = VDEV_AUX_BAD_LABEL;
142 return (SET_ERROR(EINVAL));
143 }
144
145 vdev_open_children(vd);
146
147 for (int c = 0; c < vd->vdev_children; c++) {
148 vdev_t *cvd = vd->vdev_child[c];
149
150 if (cvd->vdev_open_error) {
151 lasterror = cvd->vdev_open_error;
152 numerrors++;
153 continue;
154 }
155
156 *asize = MIN(*asize - 1, cvd->vdev_asize - 1) + 1;
157 *max_asize = MIN(*max_asize - 1, cvd->vdev_max_asize - 1) + 1;
158 *logical_ashift = MAX(*logical_ashift, cvd->vdev_ashift);
159 *physical_ashift = MAX(*physical_ashift,
160 cvd->vdev_physical_ashift);
161 }
162
163 if (numerrors == vd->vdev_children) {
164 vd->vdev_stat.vs_aux = VDEV_AUX_NO_REPLICAS;
165 return (lasterror);
166 }
167
168 return (0);
169 }
170
171 static void
vdev_mirror_close(vdev_t * vd)172 vdev_mirror_close(vdev_t *vd)
173 {
174 for (int c = 0; c < vd->vdev_children; c++)
175 vdev_close(vd->vdev_child[c]);
176 }
177
178 static void
vdev_mirror_child_done(zio_t * zio)179 vdev_mirror_child_done(zio_t *zio)
180 {
181 mirror_child_t *mc = zio->io_private;
182
183 mc->mc_error = zio->io_error;
184 mc->mc_tried = 1;
185 mc->mc_skipped = 0;
186 }
187
188 static void
vdev_mirror_scrub_done(zio_t * zio)189 vdev_mirror_scrub_done(zio_t *zio)
190 {
191 mirror_child_t *mc = zio->io_private;
192
193 if (zio->io_error == 0) {
194 zio_t *pio;
195
196 mutex_enter(&zio->io_lock);
197 while ((pio = zio_walk_parents(zio)) != NULL) {
198 mutex_enter(&pio->io_lock);
199 ASSERT3U(zio->io_size, >=, pio->io_size);
200 bcopy(zio->io_data, pio->io_data, pio->io_size);
201 mutex_exit(&pio->io_lock);
202 }
203 mutex_exit(&zio->io_lock);
204 }
205
206 zio_buf_free(zio->io_data, zio->io_size);
207
208 mc->mc_error = zio->io_error;
209 mc->mc_tried = 1;
210 mc->mc_skipped = 0;
211 }
212
213 /*
214 * Try to find a child whose DTL doesn't contain the block we want to read.
215 * If we can't, try the read on any vdev we haven't already tried.
216 */
217 static int
vdev_mirror_child_select(zio_t * zio)218 vdev_mirror_child_select(zio_t *zio)
219 {
220 mirror_map_t *mm = zio->io_vsd;
221 mirror_child_t *mc;
222 uint64_t txg = zio->io_txg;
223 int i, c;
224
225 ASSERT(zio->io_bp == NULL || BP_PHYSICAL_BIRTH(zio->io_bp) == txg);
226
227 /*
228 * Try to find a child whose DTL doesn't contain the block to read.
229 * If a child is known to be completely inaccessible (indicated by
230 * vdev_readable() returning B_FALSE), don't even try.
231 */
232 for (i = 0, c = mm->mm_preferred; i < mm->mm_children; i++, c++) {
233 if (c >= mm->mm_children)
234 c = 0;
235 mc = &mm->mm_child[c];
236 if (mc->mc_tried || mc->mc_skipped)
237 continue;
238 if (!vdev_readable(mc->mc_vd)) {
239 mc->mc_error = SET_ERROR(ENXIO);
240 mc->mc_tried = 1; /* don't even try */
241 mc->mc_skipped = 1;
242 continue;
243 }
244 if (!vdev_dtl_contains(mc->mc_vd, DTL_MISSING, txg, 1))
245 return (c);
246 mc->mc_error = SET_ERROR(ESTALE);
247 mc->mc_skipped = 1;
248 mc->mc_speculative = 1;
249 }
250
251 /*
252 * Every device is either missing or has this txg in its DTL.
253 * Look for any child we haven't already tried before giving up.
254 */
255 for (c = 0; c < mm->mm_children; c++)
256 if (!mm->mm_child[c].mc_tried)
257 return (c);
258
259 /*
260 * Every child failed. There's no place left to look.
261 */
262 return (-1);
263 }
264
265 static int
vdev_mirror_io_start(zio_t * zio)266 vdev_mirror_io_start(zio_t *zio)
267 {
268 mirror_map_t *mm;
269 mirror_child_t *mc;
270 int c, children;
271
272 mm = vdev_mirror_map_alloc(zio);
273
274 if (zio->io_type == ZIO_TYPE_READ) {
275 if ((zio->io_flags & ZIO_FLAG_SCRUB) && !mm->mm_replacing) {
276 /*
277 * For scrubbing reads we need to allocate a read
278 * buffer for each child and issue reads to all
279 * children. If any child succeeds, it will copy its
280 * data into zio->io_data in vdev_mirror_scrub_done.
281 */
282 for (c = 0; c < mm->mm_children; c++) {
283 mc = &mm->mm_child[c];
284 zio_nowait(zio_vdev_child_io(zio, zio->io_bp,
285 mc->mc_vd, mc->mc_offset,
286 zio_buf_alloc(zio->io_size), zio->io_size,
287 zio->io_type, zio->io_priority, 0,
288 vdev_mirror_scrub_done, mc));
289 }
290 return (ZIO_PIPELINE_CONTINUE);
291 }
292 /*
293 * For normal reads just pick one child.
294 */
295 c = vdev_mirror_child_select(zio);
296 children = (c >= 0);
297 } else {
298 ASSERT(zio->io_type == ZIO_TYPE_WRITE ||
299 zio->io_type == ZIO_TYPE_FREE);
300
301 /*
302 * Writes and frees go to all children.
303 */
304 c = 0;
305 children = mm->mm_children;
306 }
307
308 while (children--) {
309 mc = &mm->mm_child[c];
310 zio_nowait(zio_vdev_child_io(zio, zio->io_bp,
311 mc->mc_vd, mc->mc_offset, zio->io_data, zio->io_size,
312 zio->io_type, zio->io_priority, 0,
313 vdev_mirror_child_done, mc));
314 c++;
315 }
316
317 return (ZIO_PIPELINE_CONTINUE);
318 }
319
320 static int
vdev_mirror_worst_error(mirror_map_t * mm)321 vdev_mirror_worst_error(mirror_map_t *mm)
322 {
323 int error[2] = { 0, 0 };
324
325 for (int c = 0; c < mm->mm_children; c++) {
326 mirror_child_t *mc = &mm->mm_child[c];
327 int s = mc->mc_speculative;
328 error[s] = zio_worst_error(error[s], mc->mc_error);
329 }
330
331 return (error[0] ? error[0] : error[1]);
332 }
333
334 static void
vdev_mirror_io_done(zio_t * zio)335 vdev_mirror_io_done(zio_t *zio)
336 {
337 mirror_map_t *mm = zio->io_vsd;
338 mirror_child_t *mc;
339 int c;
340 int good_copies = 0;
341 int unexpected_errors = 0;
342
343 for (c = 0; c < mm->mm_children; c++) {
344 mc = &mm->mm_child[c];
345
346 if (mc->mc_error) {
347 if (!mc->mc_skipped)
348 unexpected_errors++;
349 } else if (mc->mc_tried) {
350 good_copies++;
351 }
352 }
353
354 if (zio->io_type == ZIO_TYPE_WRITE) {
355 /*
356 * XXX -- for now, treat partial writes as success.
357 *
358 * Now that we support write reallocation, it would be better
359 * to treat partial failure as real failure unless there are
360 * no non-degraded top-level vdevs left, and not update DTLs
361 * if we intend to reallocate.
362 */
363 /* XXPOLICY */
364 if (good_copies != mm->mm_children) {
365 /*
366 * Always require at least one good copy.
367 *
368 * For ditto blocks (io_vd == NULL), require
369 * all copies to be good.
370 *
371 * XXX -- for replacing vdevs, there's no great answer.
372 * If the old device is really dead, we may not even
373 * be able to access it -- so we only want to
374 * require good writes to the new device. But if
375 * the new device turns out to be flaky, we want
376 * to be able to detach it -- which requires all
377 * writes to the old device to have succeeded.
378 */
379 if (good_copies == 0 || zio->io_vd == NULL)
380 zio->io_error = vdev_mirror_worst_error(mm);
381 }
382 return;
383 } else if (zio->io_type == ZIO_TYPE_FREE) {
384 return;
385 }
386
387 ASSERT(zio->io_type == ZIO_TYPE_READ);
388
389 /*
390 * If we don't have a good copy yet, keep trying other children.
391 */
392 /* XXPOLICY */
393 if (good_copies == 0 && (c = vdev_mirror_child_select(zio)) != -1) {
394 ASSERT(c >= 0 && c < mm->mm_children);
395 mc = &mm->mm_child[c];
396 zio_vdev_io_redone(zio);
397 zio_nowait(zio_vdev_child_io(zio, zio->io_bp,
398 mc->mc_vd, mc->mc_offset, zio->io_data, zio->io_size,
399 ZIO_TYPE_READ, zio->io_priority, 0,
400 vdev_mirror_child_done, mc));
401 return;
402 }
403
404 /* XXPOLICY */
405 if (good_copies == 0) {
406 zio->io_error = vdev_mirror_worst_error(mm);
407 ASSERT(zio->io_error != 0);
408 }
409
410 if (good_copies && spa_writeable(zio->io_spa) &&
411 (unexpected_errors ||
412 (zio->io_flags & ZIO_FLAG_RESILVER) ||
413 ((zio->io_flags & ZIO_FLAG_SCRUB) && mm->mm_replacing))) {
414 /*
415 * Use the good data we have in hand to repair damaged children.
416 */
417 for (c = 0; c < mm->mm_children; c++) {
418 /*
419 * Don't rewrite known good children.
420 * Not only is it unnecessary, it could
421 * actually be harmful: if the system lost
422 * power while rewriting the only good copy,
423 * there would be no good copies left!
424 */
425 mc = &mm->mm_child[c];
426
427 if (mc->mc_error == 0) {
428 if (mc->mc_tried)
429 continue;
430 if (!(zio->io_flags & ZIO_FLAG_SCRUB) &&
431 !vdev_dtl_contains(mc->mc_vd, DTL_PARTIAL,
432 zio->io_txg, 1))
433 continue;
434 mc->mc_error = SET_ERROR(ESTALE);
435 }
436
437 zio_nowait(zio_vdev_child_io(zio, zio->io_bp,
438 mc->mc_vd, mc->mc_offset,
439 zio->io_data, zio->io_size,
440 ZIO_TYPE_WRITE, ZIO_PRIORITY_ASYNC_WRITE,
441 ZIO_FLAG_IO_REPAIR | (unexpected_errors ?
442 ZIO_FLAG_SELF_HEAL : 0), NULL, NULL));
443 }
444 }
445 }
446
447 static void
vdev_mirror_state_change(vdev_t * vd,int faulted,int degraded)448 vdev_mirror_state_change(vdev_t *vd, int faulted, int degraded)
449 {
450 if (faulted == vd->vdev_children)
451 vdev_set_state(vd, B_FALSE, VDEV_STATE_CANT_OPEN,
452 VDEV_AUX_NO_REPLICAS);
453 else if (degraded + faulted != 0)
454 vdev_set_state(vd, B_FALSE, VDEV_STATE_DEGRADED, VDEV_AUX_NONE);
455 else
456 vdev_set_state(vd, B_FALSE, VDEV_STATE_HEALTHY, VDEV_AUX_NONE);
457 }
458
459 vdev_ops_t vdev_mirror_ops = {
460 vdev_mirror_open,
461 vdev_mirror_close,
462 vdev_default_asize,
463 vdev_mirror_io_start,
464 vdev_mirror_io_done,
465 vdev_mirror_state_change,
466 NULL,
467 NULL,
468 VDEV_TYPE_MIRROR, /* name of this vdev type */
469 B_FALSE /* not a leaf vdev */
470 };
471
472 vdev_ops_t vdev_replacing_ops = {
473 vdev_mirror_open,
474 vdev_mirror_close,
475 vdev_default_asize,
476 vdev_mirror_io_start,
477 vdev_mirror_io_done,
478 vdev_mirror_state_change,
479 NULL,
480 NULL,
481 VDEV_TYPE_REPLACING, /* name of this vdev type */
482 B_FALSE /* not a leaf vdev */
483 };
484
485 vdev_ops_t vdev_spare_ops = {
486 vdev_mirror_open,
487 vdev_mirror_close,
488 vdev_default_asize,
489 vdev_mirror_io_start,
490 vdev_mirror_io_done,
491 vdev_mirror_state_change,
492 NULL,
493 NULL,
494 VDEV_TYPE_SPARE, /* name of this vdev type */
495 B_FALSE /* not a leaf vdev */
496 };
497