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ZIL: Call brt_pending_add() replaying TX_CLONE_RANGE
[zfs.git] / module / zfs / vdev_raidz.c
blob3445fa9d35d5dd8918f06bba429416052cffcd8f
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 https://opensource.org/licenses/CDDL-1.0.
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 /*
23 * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
24 * Copyright (c) 2012, 2020 by Delphix. All rights reserved.
25 * Copyright (c) 2016 Gvozden Nešković. All rights reserved.
26 */
27
28 #include <sys/zfs_context.h>
29 #include <sys/spa.h>
30 #include <sys/vdev_impl.h>
31 #include <sys/zio.h>
32 #include <sys/zio_checksum.h>
33 #include <sys/abd.h>
34 #include <sys/fs/zfs.h>
35 #include <sys/fm/fs/zfs.h>
36 #include <sys/vdev_raidz.h>
37 #include <sys/vdev_raidz_impl.h>
38 #include <sys/vdev_draid.h>
39
40 #ifdef ZFS_DEBUG
41 #include <sys/vdev.h> /* For vdev_xlate() in vdev_raidz_io_verify() */
42 #endif
43
44 /*
45 * Virtual device vector for RAID-Z.
46 *
47 * This vdev supports single, double, and triple parity. For single parity,
48 * we use a simple XOR of all the data columns. For double or triple parity,
49 * we use a special case of Reed-Solomon coding. This extends the
50 * technique described in "The mathematics of RAID-6" by H. Peter Anvin by
51 * drawing on the system described in "A Tutorial on Reed-Solomon Coding for
52 * Fault-Tolerance in RAID-like Systems" by James S. Plank on which the
53 * former is also based. The latter is designed to provide higher performance
54 * for writes.
55 *
56 * Note that the Plank paper claimed to support arbitrary N+M, but was then
57 * amended six years later identifying a critical flaw that invalidates its
58 * claims. Nevertheless, the technique can be adapted to work for up to
59 * triple parity. For additional parity, the amendment "Note: Correction to
60 * the 1997 Tutorial on Reed-Solomon Coding" by James S. Plank and Ying Ding
61 * is viable, but the additional complexity means that write performance will
62 * suffer.
63 *
64 * All of the methods above operate on a Galois field, defined over the
65 * integers mod 2^N. In our case we choose N=8 for GF(8) so that all elements
66 * can be expressed with a single byte. Briefly, the operations on the
67 * field are defined as follows:
68 *
69 * o addition (+) is represented by a bitwise XOR
70 * o subtraction (-) is therefore identical to addition: A + B = A - B
71 * o multiplication of A by 2 is defined by the following bitwise expression:
72 *
73 * (A * 2)_7 = A_6
74 * (A * 2)_6 = A_5
75 * (A * 2)_5 = A_4
76 * (A * 2)_4 = A_3 + A_7
77 * (A * 2)_3 = A_2 + A_7
78 * (A * 2)_2 = A_1 + A_7
79 * (A * 2)_1 = A_0
80 * (A * 2)_0 = A_7
81 *
82 * In C, multiplying by 2 is therefore ((a << 1) ^ ((a & 0x80) ? 0x1d : 0)).
83 * As an aside, this multiplication is derived from the error correcting
84 * primitive polynomial x^8 + x^4 + x^3 + x^2 + 1.
85 *
86 * Observe that any number in the field (except for 0) can be expressed as a
87 * power of 2 -- a generator for the field. We store a table of the powers of
88 * 2 and logs base 2 for quick look ups, and exploit the fact that A * B can
89 * be rewritten as 2^(log_2(A) + log_2(B)) (where '+' is normal addition rather
90 * than field addition). The inverse of a field element A (A^-1) is therefore
91 * A ^ (255 - 1) = A^254.
92 *
93 * The up-to-three parity columns, P, Q, R over several data columns,
94 * D_0, ... D_n-1, can be expressed by field operations:
95 *
96 * P = D_0 + D_1 + ... + D_n-2 + D_n-1
97 * Q = 2^n-1 * D_0 + 2^n-2 * D_1 + ... + 2^1 * D_n-2 + 2^0 * D_n-1
98 * = ((...((D_0) * 2 + D_1) * 2 + ...) * 2 + D_n-2) * 2 + D_n-1
99 * R = 4^n-1 * D_0 + 4^n-2 * D_1 + ... + 4^1 * D_n-2 + 4^0 * D_n-1
100 * = ((...((D_0) * 4 + D_1) * 4 + ...) * 4 + D_n-2) * 4 + D_n-1
101 *
102 * We chose 1, 2, and 4 as our generators because 1 corresponds to the trivial
103 * XOR operation, and 2 and 4 can be computed quickly and generate linearly-
104 * independent coefficients. (There are no additional coefficients that have
105 * this property which is why the uncorrected Plank method breaks down.)
106 *
107 * See the reconstruction code below for how P, Q and R can used individually
108 * or in concert to recover missing data columns.
109 */
110
111 #define VDEV_RAIDZ_P 0
112 #define VDEV_RAIDZ_Q 1
113 #define VDEV_RAIDZ_R 2
114
115 #define VDEV_RAIDZ_MUL_2(x) (((x) << 1) ^ (((x) & 0x80) ? 0x1d : 0))
116 #define VDEV_RAIDZ_MUL_4(x) (VDEV_RAIDZ_MUL_2(VDEV_RAIDZ_MUL_2(x)))
117
118 /*
119 * We provide a mechanism to perform the field multiplication operation on a
120 * 64-bit value all at once rather than a byte at a time. This works by
121 * creating a mask from the top bit in each byte and using that to
122 * conditionally apply the XOR of 0x1d.
123 */
124 #define VDEV_RAIDZ_64MUL_2(x, mask) \
125 { \
126 (mask) = (x) & 0x8080808080808080ULL; \
127 (mask) = ((mask) << 1) - ((mask) >> 7); \
128 (x) = (((x) << 1) & 0xfefefefefefefefeULL) ^ \
129 ((mask) & 0x1d1d1d1d1d1d1d1dULL); \
130 }
131
132 #define VDEV_RAIDZ_64MUL_4(x, mask) \
133 { \
134 VDEV_RAIDZ_64MUL_2((x), mask); \
135 VDEV_RAIDZ_64MUL_2((x), mask); \
136 }
137
138 static void
139 vdev_raidz_row_free(raidz_row_t *rr)
140 {
141 for (int c = 0; c < rr->rr_cols; c++) {
142 raidz_col_t *rc = &rr->rr_col[c];
143
144 if (rc->rc_size != 0)
145 abd_free(rc->rc_abd);
146 if (rc->rc_orig_data != NULL)
147 abd_free(rc->rc_orig_data);
148 }
149
150 if (rr->rr_abd_empty != NULL)
151 abd_free(rr->rr_abd_empty);
152
153 kmem_free(rr, offsetof(raidz_row_t, rr_col[rr->rr_scols]));
154 }
155
156 void
157 vdev_raidz_map_free(raidz_map_t *rm)
158 {
159 for (int i = 0; i < rm->rm_nrows; i++)
160 vdev_raidz_row_free(rm->rm_row[i]);
161
162 kmem_free(rm, offsetof(raidz_map_t, rm_row[rm->rm_nrows]));
163 }
164
165 static void
166 vdev_raidz_map_free_vsd(zio_t *zio)
167 {
168 raidz_map_t *rm = zio->io_vsd;
169
170 vdev_raidz_map_free(rm);
171 }
172
173 const zio_vsd_ops_t vdev_raidz_vsd_ops = {
174 .vsd_free = vdev_raidz_map_free_vsd,
175 };
176
177 static void
178 vdev_raidz_map_alloc_write(zio_t *zio, raidz_map_t *rm, uint64_t ashift)
179 {
180 int c;
181 int nwrapped = 0;
182 uint64_t off = 0;
183 raidz_row_t *rr = rm->rm_row[0];
184
185 ASSERT3U(zio->io_type, ==, ZIO_TYPE_WRITE);
186 ASSERT3U(rm->rm_nrows, ==, 1);
187
188 /*
189 * Pad any parity columns with additional space to account for skip
190 * sectors.
191 */
192 if (rm->rm_skipstart < rr->rr_firstdatacol) {
193 ASSERT0(rm->rm_skipstart);
194 nwrapped = rm->rm_nskip;
195 } else if (rr->rr_scols < (rm->rm_skipstart + rm->rm_nskip)) {
196 nwrapped =
197 (rm->rm_skipstart + rm->rm_nskip) % rr->rr_scols;
198 }
199
200 /*
201 * Optional single skip sectors (rc_size == 0) will be handled in
202 * vdev_raidz_io_start_write().
203 */
204 int skipped = rr->rr_scols - rr->rr_cols;
205
206 /* Allocate buffers for the parity columns */
207 for (c = 0; c < rr->rr_firstdatacol; c++) {
208 raidz_col_t *rc = &rr->rr_col[c];
209
210 /*
211 * Parity columns will pad out a linear ABD to account for
212 * the skip sector. A linear ABD is used here because
213 * parity calculations use the ABD buffer directly to calculate
214 * parity. This avoids doing a memcpy back to the ABD after the
215 * parity has been calculated. By issuing the parity column
216 * with the skip sector we can reduce contention on the child
217 * VDEV queue locks (vq_lock).
218 */
219 if (c < nwrapped) {
220 rc->rc_abd = abd_alloc_linear(
221 rc->rc_size + (1ULL << ashift), B_FALSE);
222 abd_zero_off(rc->rc_abd, rc->rc_size, 1ULL << ashift);
223 skipped++;
224 } else {
225 rc->rc_abd = abd_alloc_linear(rc->rc_size, B_FALSE);
226 }
227 }
228
229 for (off = 0; c < rr->rr_cols; c++) {
230 raidz_col_t *rc = &rr->rr_col[c];
231 abd_t *abd = abd_get_offset_struct(&rc->rc_abdstruct,
232 zio->io_abd, off, rc->rc_size);
233
234 /*
235 * Generate I/O for skip sectors to improve aggregation
236 * continuity. We will use gang ABD's to reduce contention
237 * on the child VDEV queue locks (vq_lock) by issuing
238 * a single I/O that contains the data and skip sector.
239 *
240 * It is important to make sure that rc_size is not updated
241 * even though we are adding a skip sector to the ABD. When
242 * calculating the parity in vdev_raidz_generate_parity_row()
243 * the rc_size is used to iterate through the ABD's. We can
244 * not have zero'd out skip sectors used for calculating
245 * parity for raidz, because those same sectors are not used
246 * during reconstruction.
247 */
248 if (c >= rm->rm_skipstart && skipped < rm->rm_nskip) {
249 rc->rc_abd = abd_alloc_gang();
250 abd_gang_add(rc->rc_abd, abd, B_TRUE);
251 abd_gang_add(rc->rc_abd,
252 abd_get_zeros(1ULL << ashift), B_TRUE);
253 skipped++;
254 } else {
255 rc->rc_abd = abd;
256 }
257 off += rc->rc_size;
258 }
259
260 ASSERT3U(off, ==, zio->io_size);
261 ASSERT3S(skipped, ==, rm->rm_nskip);
262 }
263
264 static void
265 vdev_raidz_map_alloc_read(zio_t *zio, raidz_map_t *rm)
266 {
267 int c;
268 raidz_row_t *rr = rm->rm_row[0];
269
270 ASSERT3U(rm->rm_nrows, ==, 1);
271
272 /* Allocate buffers for the parity columns */
273 for (c = 0; c < rr->rr_firstdatacol; c++)
274 rr->rr_col[c].rc_abd =
275 abd_alloc_linear(rr->rr_col[c].rc_size, B_FALSE);
276
277 for (uint64_t off = 0; c < rr->rr_cols; c++) {
278 raidz_col_t *rc = &rr->rr_col[c];
279 rc->rc_abd = abd_get_offset_struct(&rc->rc_abdstruct,
280 zio->io_abd, off, rc->rc_size);
281 off += rc->rc_size;
282 }
283 }
284
285 /*
286 * Divides the IO evenly across all child vdevs; usually, dcols is
287 * the number of children in the target vdev.
288 *
289 * Avoid inlining the function to keep vdev_raidz_io_start(), which
290 * is this functions only caller, as small as possible on the stack.
291 */
292 noinline raidz_map_t *
293 vdev_raidz_map_alloc(zio_t *zio, uint64_t ashift, uint64_t dcols,
294 uint64_t nparity)
295 {
296 raidz_row_t *rr;
297 /* The starting RAIDZ (parent) vdev sector of the block. */
298 uint64_t b = zio->io_offset >> ashift;
299 /* The zio's size in units of the vdev's minimum sector size. */
300 uint64_t s = zio->io_size >> ashift;
301 /* The first column for this stripe. */
302 uint64_t f = b % dcols;
303 /* The starting byte offset on each child vdev. */
304 uint64_t o = (b / dcols) << ashift;
305 uint64_t q, r, c, bc, col, acols, scols, coff, devidx, asize, tot;
306
307 raidz_map_t *rm =
308 kmem_zalloc(offsetof(raidz_map_t, rm_row[1]), KM_SLEEP);
309 rm->rm_nrows = 1;
310
311 /*
312 * "Quotient": The number of data sectors for this stripe on all but
313 * the "big column" child vdevs that also contain "remainder" data.
314 */
315 q = s / (dcols - nparity);
316
317 /*
318 * "Remainder": The number of partial stripe data sectors in this I/O.
319 * This will add a sector to some, but not all, child vdevs.
320 */
321 r = s - q * (dcols - nparity);
322
323 /* The number of "big columns" - those which contain remainder data. */
324 bc = (r == 0 ? 0 : r + nparity);
325
326 /*
327 * The total number of data and parity sectors associated with
328 * this I/O.
329 */
330 tot = s + nparity * (q + (r == 0 ? 0 : 1));
331
332 /*
333 * acols: The columns that will be accessed.
334 * scols: The columns that will be accessed or skipped.
335 */
336 if (q == 0) {
337 /* Our I/O request doesn't span all child vdevs. */
338 acols = bc;
339 scols = MIN(dcols, roundup(bc, nparity + 1));
340 } else {
341 acols = dcols;
342 scols = dcols;
343 }
344
345 ASSERT3U(acols, <=, scols);
346
347 rr = kmem_alloc(offsetof(raidz_row_t, rr_col[scols]), KM_SLEEP);
348 rm->rm_row[0] = rr;
349
350 rr->rr_cols = acols;
351 rr->rr_scols = scols;
352 rr->rr_bigcols = bc;
353 rr->rr_missingdata = 0;
354 rr->rr_missingparity = 0;
355 rr->rr_firstdatacol = nparity;
356 rr->rr_abd_empty = NULL;
357 rr->rr_nempty = 0;
358 #ifdef ZFS_DEBUG
359 rr->rr_offset = zio->io_offset;
360 rr->rr_size = zio->io_size;
361 #endif
362
363 asize = 0;
364
365 for (c = 0; c < scols; c++) {
366 raidz_col_t *rc = &rr->rr_col[c];
367 col = f + c;
368 coff = o;
369 if (col >= dcols) {
370 col -= dcols;
371 coff += 1ULL << ashift;
372 }
373 rc->rc_devidx = col;
374 rc->rc_offset = coff;
375 rc->rc_abd = NULL;
376 rc->rc_orig_data = NULL;
377 rc->rc_error = 0;
378 rc->rc_tried = 0;
379 rc->rc_skipped = 0;
380 rc->rc_force_repair = 0;
381 rc->rc_allow_repair = 1;
382 rc->rc_need_orig_restore = B_FALSE;
383
384 if (c >= acols)
385 rc->rc_size = 0;
386 else if (c < bc)
387 rc->rc_size = (q + 1) << ashift;
388 else
389 rc->rc_size = q << ashift;
390
391 asize += rc->rc_size;
392 }
393
394 ASSERT3U(asize, ==, tot << ashift);
395 rm->rm_nskip = roundup(tot, nparity + 1) - tot;
396 rm->rm_skipstart = bc;
397
398 /*
399 * If all data stored spans all columns, there's a danger that parity
400 * will always be on the same device and, since parity isn't read
401 * during normal operation, that device's I/O bandwidth won't be
402 * used effectively. We therefore switch the parity every 1MB.
403 *
404 * ... at least that was, ostensibly, the theory. As a practical
405 * matter unless we juggle the parity between all devices evenly, we
406 * won't see any benefit. Further, occasional writes that aren't a
407 * multiple of the LCM of the number of children and the minimum
408 * stripe width are sufficient to avoid pessimal behavior.
409 * Unfortunately, this decision created an implicit on-disk format
410 * requirement that we need to support for all eternity, but only
411 * for single-parity RAID-Z.
412 *
413 * If we intend to skip a sector in the zeroth column for padding
414 * we must make sure to note this swap. We will never intend to
415 * skip the first column since at least one data and one parity
416 * column must appear in each row.
417 */
418 ASSERT(rr->rr_cols >= 2);
419 ASSERT(rr->rr_col[0].rc_size == rr->rr_col[1].rc_size);
420
421 if (rr->rr_firstdatacol == 1 && (zio->io_offset & (1ULL << 20))) {
422 devidx = rr->rr_col[0].rc_devidx;
423 o = rr->rr_col[0].rc_offset;
424 rr->rr_col[0].rc_devidx = rr->rr_col[1].rc_devidx;
425 rr->rr_col[0].rc_offset = rr->rr_col[1].rc_offset;
426 rr->rr_col[1].rc_devidx = devidx;
427 rr->rr_col[1].rc_offset = o;
428
429 if (rm->rm_skipstart == 0)
430 rm->rm_skipstart = 1;
431 }
432
433 if (zio->io_type == ZIO_TYPE_WRITE) {
434 vdev_raidz_map_alloc_write(zio, rm, ashift);
435 } else {
436 vdev_raidz_map_alloc_read(zio, rm);
437 }
438
439 /* init RAIDZ parity ops */
440 rm->rm_ops = vdev_raidz_math_get_ops();
441
442 return (rm);
443 }
444
445 struct pqr_struct {
446 uint64_t *p;
447 uint64_t *q;
448 uint64_t *r;
449 };
450
451 static int
452 vdev_raidz_p_func(void *buf, size_t size, void *private)
453 {
454 struct pqr_struct *pqr = private;
455 const uint64_t *src = buf;
456 int i, cnt = size / sizeof (src[0]);
457
458 ASSERT(pqr->p && !pqr->q && !pqr->r);
459
460 for (i = 0; i < cnt; i++, src++, pqr->p++)
461 *pqr->p ^= *src;
462
463 return (0);
464 }
465
466 static int
467 vdev_raidz_pq_func(void *buf, size_t size, void *private)
468 {
469 struct pqr_struct *pqr = private;
470 const uint64_t *src = buf;
471 uint64_t mask;
472 int i, cnt = size / sizeof (src[0]);
473
474 ASSERT(pqr->p && pqr->q && !pqr->r);
475
476 for (i = 0; i < cnt; i++, src++, pqr->p++, pqr->q++) {
477 *pqr->p ^= *src;
478 VDEV_RAIDZ_64MUL_2(*pqr->q, mask);
479 *pqr->q ^= *src;
480 }
481
482 return (0);
483 }
484
485 static int
486 vdev_raidz_pqr_func(void *buf, size_t size, void *private)
487 {
488 struct pqr_struct *pqr = private;
489 const uint64_t *src = buf;
490 uint64_t mask;
491 int i, cnt = size / sizeof (src[0]);
492
493 ASSERT(pqr->p && pqr->q && pqr->r);
494
495 for (i = 0; i < cnt; i++, src++, pqr->p++, pqr->q++, pqr->r++) {
496 *pqr->p ^= *src;
497 VDEV_RAIDZ_64MUL_2(*pqr->q, mask);
498 *pqr->q ^= *src;
499 VDEV_RAIDZ_64MUL_4(*pqr->r, mask);
500 *pqr->r ^= *src;
501 }
502
503 return (0);
504 }
505
506 static void
507 vdev_raidz_generate_parity_p(raidz_row_t *rr)
508 {
509 uint64_t *p = abd_to_buf(rr->rr_col[VDEV_RAIDZ_P].rc_abd);
510
511 for (int c = rr->rr_firstdatacol; c < rr->rr_cols; c++) {
512 abd_t *src = rr->rr_col[c].rc_abd;
513
514 if (c == rr->rr_firstdatacol) {
515 abd_copy_to_buf(p, src, rr->rr_col[c].rc_size);
516 } else {
517 struct pqr_struct pqr = { p, NULL, NULL };
518 (void) abd_iterate_func(src, 0, rr->rr_col[c].rc_size,
519 vdev_raidz_p_func, &pqr);
520 }
521 }
522 }
523
524 static void
525 vdev_raidz_generate_parity_pq(raidz_row_t *rr)
526 {
527 uint64_t *p = abd_to_buf(rr->rr_col[VDEV_RAIDZ_P].rc_abd);
528 uint64_t *q = abd_to_buf(rr->rr_col[VDEV_RAIDZ_Q].rc_abd);
529 uint64_t pcnt = rr->rr_col[VDEV_RAIDZ_P].rc_size / sizeof (p[0]);
530 ASSERT(rr->rr_col[VDEV_RAIDZ_P].rc_size ==
531 rr->rr_col[VDEV_RAIDZ_Q].rc_size);
532
533 for (int c = rr->rr_firstdatacol; c < rr->rr_cols; c++) {
534 abd_t *src = rr->rr_col[c].rc_abd;
535
536 uint64_t ccnt = rr->rr_col[c].rc_size / sizeof (p[0]);
537
538 if (c == rr->rr_firstdatacol) {
539 ASSERT(ccnt == pcnt || ccnt == 0);
540 abd_copy_to_buf(p, src, rr->rr_col[c].rc_size);
541 (void) memcpy(q, p, rr->rr_col[c].rc_size);
542
543 for (uint64_t i = ccnt; i < pcnt; i++) {
544 p[i] = 0;
545 q[i] = 0;
546 }
547 } else {
548 struct pqr_struct pqr = { p, q, NULL };
549
550 ASSERT(ccnt <= pcnt);
551 (void) abd_iterate_func(src, 0, rr->rr_col[c].rc_size,
552 vdev_raidz_pq_func, &pqr);
553
554 /*
555 * Treat short columns as though they are full of 0s.
556 * Note that there's therefore nothing needed for P.
557 */
558 uint64_t mask;
559 for (uint64_t i = ccnt; i < pcnt; i++) {
560 VDEV_RAIDZ_64MUL_2(q[i], mask);
561 }
562 }
563 }
564 }
565
566 static void
567 vdev_raidz_generate_parity_pqr(raidz_row_t *rr)
568 {
569 uint64_t *p = abd_to_buf(rr->rr_col[VDEV_RAIDZ_P].rc_abd);
570 uint64_t *q = abd_to_buf(rr->rr_col[VDEV_RAIDZ_Q].rc_abd);
571 uint64_t *r = abd_to_buf(rr->rr_col[VDEV_RAIDZ_R].rc_abd);
572 uint64_t pcnt = rr->rr_col[VDEV_RAIDZ_P].rc_size / sizeof (p[0]);
573 ASSERT(rr->rr_col[VDEV_RAIDZ_P].rc_size ==
574 rr->rr_col[VDEV_RAIDZ_Q].rc_size);
575 ASSERT(rr->rr_col[VDEV_RAIDZ_P].rc_size ==
576 rr->rr_col[VDEV_RAIDZ_R].rc_size);
577
578 for (int c = rr->rr_firstdatacol; c < rr->rr_cols; c++) {
579 abd_t *src = rr->rr_col[c].rc_abd;
580
581 uint64_t ccnt = rr->rr_col[c].rc_size / sizeof (p[0]);
582
583 if (c == rr->rr_firstdatacol) {
584 ASSERT(ccnt == pcnt || ccnt == 0);
585 abd_copy_to_buf(p, src, rr->rr_col[c].rc_size);
586 (void) memcpy(q, p, rr->rr_col[c].rc_size);
587 (void) memcpy(r, p, rr->rr_col[c].rc_size);
588
589 for (uint64_t i = ccnt; i < pcnt; i++) {
590 p[i] = 0;
591 q[i] = 0;
592 r[i] = 0;
593 }
594 } else {
595 struct pqr_struct pqr = { p, q, r };
596
597 ASSERT(ccnt <= pcnt);
598 (void) abd_iterate_func(src, 0, rr->rr_col[c].rc_size,
599 vdev_raidz_pqr_func, &pqr);
600
601 /*
602 * Treat short columns as though they are full of 0s.
603 * Note that there's therefore nothing needed for P.
604 */
605 uint64_t mask;
606 for (uint64_t i = ccnt; i < pcnt; i++) {
607 VDEV_RAIDZ_64MUL_2(q[i], mask);
608 VDEV_RAIDZ_64MUL_4(r[i], mask);
609 }
610 }
611 }
612 }
613
614 /*
615 * Generate RAID parity in the first virtual columns according to the number of
616 * parity columns available.
617 */
618 void
619 vdev_raidz_generate_parity_row(raidz_map_t *rm, raidz_row_t *rr)
620 {
621 ASSERT3U(rr->rr_cols, !=, 0);
622
623 /* Generate using the new math implementation */
624 if (vdev_raidz_math_generate(rm, rr) != RAIDZ_ORIGINAL_IMPL)
625 return;
626
627 switch (rr->rr_firstdatacol) {
628 case 1:
629 vdev_raidz_generate_parity_p(rr);
630 break;
631 case 2:
632 vdev_raidz_generate_parity_pq(rr);
633 break;
634 case 3:
635 vdev_raidz_generate_parity_pqr(rr);
636 break;
637 default:
638 cmn_err(CE_PANIC, "invalid RAID-Z configuration");
639 }
640 }
641
642 void
643 vdev_raidz_generate_parity(raidz_map_t *rm)
644 {
645 for (int i = 0; i < rm->rm_nrows; i++) {
646 raidz_row_t *rr = rm->rm_row[i];
647 vdev_raidz_generate_parity_row(rm, rr);
648 }
649 }
650
651 static int
652 vdev_raidz_reconst_p_func(void *dbuf, void *sbuf, size_t size, void *private)
653 {
654 (void) private;
655 uint64_t *dst = dbuf;
656 uint64_t *src = sbuf;
657 int cnt = size / sizeof (src[0]);
658
659 for (int i = 0; i < cnt; i++) {
660 dst[i] ^= src[i];
661 }
662
663 return (0);
664 }
665
666 static int
667 vdev_raidz_reconst_q_pre_func(void *dbuf, void *sbuf, size_t size,
668 void *private)
669 {
670 (void) private;
671 uint64_t *dst = dbuf;
672 uint64_t *src = sbuf;
673 uint64_t mask;
674 int cnt = size / sizeof (dst[0]);
675
676 for (int i = 0; i < cnt; i++, dst++, src++) {
677 VDEV_RAIDZ_64MUL_2(*dst, mask);
678 *dst ^= *src;
679 }
680
681 return (0);
682 }
683
684 static int
685 vdev_raidz_reconst_q_pre_tail_func(void *buf, size_t size, void *private)
686 {
687 (void) private;
688 uint64_t *dst = buf;
689 uint64_t mask;
690 int cnt = size / sizeof (dst[0]);
691
692 for (int i = 0; i < cnt; i++, dst++) {
693 /* same operation as vdev_raidz_reconst_q_pre_func() on dst */
694 VDEV_RAIDZ_64MUL_2(*dst, mask);
695 }
696
697 return (0);
698 }
699
700 struct reconst_q_struct {
701 uint64_t *q;
702 int exp;
703 };
704
705 static int
706 vdev_raidz_reconst_q_post_func(void *buf, size_t size, void *private)
707 {
708 struct reconst_q_struct *rq = private;
709 uint64_t *dst = buf;
710 int cnt = size / sizeof (dst[0]);
711
712 for (int i = 0; i < cnt; i++, dst++, rq->q++) {
713 int j;
714 uint8_t *b;
715
716 *dst ^= *rq->q;
717 for (j = 0, b = (uint8_t *)dst; j < 8; j++, b++) {
718 *b = vdev_raidz_exp2(*b, rq->exp);
719 }
720 }
721
722 return (0);
723 }
724
725 struct reconst_pq_struct {
726 uint8_t *p;
727 uint8_t *q;
728 uint8_t *pxy;
729 uint8_t *qxy;
730 int aexp;
731 int bexp;
732 };
733
734 static int
735 vdev_raidz_reconst_pq_func(void *xbuf, void *ybuf, size_t size, void *private)
736 {
737 struct reconst_pq_struct *rpq = private;
738 uint8_t *xd = xbuf;
739 uint8_t *yd = ybuf;
740
741 for (int i = 0; i < size;
742 i++, rpq->p++, rpq->q++, rpq->pxy++, rpq->qxy++, xd++, yd++) {
743 *xd = vdev_raidz_exp2(*rpq->p ^ *rpq->pxy, rpq->aexp) ^
744 vdev_raidz_exp2(*rpq->q ^ *rpq->qxy, rpq->bexp);
745 *yd = *rpq->p ^ *rpq->pxy ^ *xd;
746 }
747
748 return (0);
749 }
750
751 static int
752 vdev_raidz_reconst_pq_tail_func(void *xbuf, size_t size, void *private)
753 {
754 struct reconst_pq_struct *rpq = private;
755 uint8_t *xd = xbuf;
756
757 for (int i = 0; i < size;
758 i++, rpq->p++, rpq->q++, rpq->pxy++, rpq->qxy++, xd++) {
759 /* same operation as vdev_raidz_reconst_pq_func() on xd */
760 *xd = vdev_raidz_exp2(*rpq->p ^ *rpq->pxy, rpq->aexp) ^
761 vdev_raidz_exp2(*rpq->q ^ *rpq->qxy, rpq->bexp);
762 }
763
764 return (0);
765 }
766
767 static void
768 vdev_raidz_reconstruct_p(raidz_row_t *rr, int *tgts, int ntgts)
769 {
770 int x = tgts[0];
771 abd_t *dst, *src;
772
773 ASSERT3U(ntgts, ==, 1);
774 ASSERT3U(x, >=, rr->rr_firstdatacol);
775 ASSERT3U(x, <, rr->rr_cols);
776
777 ASSERT3U(rr->rr_col[x].rc_size, <=, rr->rr_col[VDEV_RAIDZ_P].rc_size);
778
779 src = rr->rr_col[VDEV_RAIDZ_P].rc_abd;
780 dst = rr->rr_col[x].rc_abd;
781
782 abd_copy_from_buf(dst, abd_to_buf(src), rr->rr_col[x].rc_size);
783
784 for (int c = rr->rr_firstdatacol; c < rr->rr_cols; c++) {
785 uint64_t size = MIN(rr->rr_col[x].rc_size,
786 rr->rr_col[c].rc_size);
787
788 src = rr->rr_col[c].rc_abd;
789
790 if (c == x)
791 continue;
792
793 (void) abd_iterate_func2(dst, src, 0, 0, size,
794 vdev_raidz_reconst_p_func, NULL);
795 }
796 }
797
798 static void
799 vdev_raidz_reconstruct_q(raidz_row_t *rr, int *tgts, int ntgts)
800 {
801 int x = tgts[0];
802 int c, exp;
803 abd_t *dst, *src;
804
805 ASSERT(ntgts == 1);
806
807 ASSERT(rr->rr_col[x].rc_size <= rr->rr_col[VDEV_RAIDZ_Q].rc_size);
808
809 for (c = rr->rr_firstdatacol; c < rr->rr_cols; c++) {
810 uint64_t size = (c == x) ? 0 : MIN(rr->rr_col[x].rc_size,
811 rr->rr_col[c].rc_size);
812
813 src = rr->rr_col[c].rc_abd;
814 dst = rr->rr_col[x].rc_abd;
815
816 if (c == rr->rr_firstdatacol) {
817 abd_copy(dst, src, size);
818 if (rr->rr_col[x].rc_size > size) {
819 abd_zero_off(dst, size,
820 rr->rr_col[x].rc_size - size);
821 }
822 } else {
823 ASSERT3U(size, <=, rr->rr_col[x].rc_size);
824 (void) abd_iterate_func2(dst, src, 0, 0, size,
825 vdev_raidz_reconst_q_pre_func, NULL);
826 (void) abd_iterate_func(dst,
827 size, rr->rr_col[x].rc_size - size,
828 vdev_raidz_reconst_q_pre_tail_func, NULL);
829 }
830 }
831
832 src = rr->rr_col[VDEV_RAIDZ_Q].rc_abd;
833 dst = rr->rr_col[x].rc_abd;
834 exp = 255 - (rr->rr_cols - 1 - x);
835
836 struct reconst_q_struct rq = { abd_to_buf(src), exp };
837 (void) abd_iterate_func(dst, 0, rr->rr_col[x].rc_size,
838 vdev_raidz_reconst_q_post_func, &rq);
839 }
840
841 static void
842 vdev_raidz_reconstruct_pq(raidz_row_t *rr, int *tgts, int ntgts)
843 {
844 uint8_t *p, *q, *pxy, *qxy, tmp, a, b, aexp, bexp;
845 abd_t *pdata, *qdata;
846 uint64_t xsize, ysize;
847 int x = tgts[0];
848 int y = tgts[1];
849 abd_t *xd, *yd;
850
851 ASSERT(ntgts == 2);
852 ASSERT(x < y);
853 ASSERT(x >= rr->rr_firstdatacol);
854 ASSERT(y < rr->rr_cols);
855
856 ASSERT(rr->rr_col[x].rc_size >= rr->rr_col[y].rc_size);
857
858 /*
859 * Move the parity data aside -- we're going to compute parity as
860 * though columns x and y were full of zeros -- Pxy and Qxy. We want to
861 * reuse the parity generation mechanism without trashing the actual
862 * parity so we make those columns appear to be full of zeros by
863 * setting their lengths to zero.
864 */
865 pdata = rr->rr_col[VDEV_RAIDZ_P].rc_abd;
866 qdata = rr->rr_col[VDEV_RAIDZ_Q].rc_abd;
867 xsize = rr->rr_col[x].rc_size;
868 ysize = rr->rr_col[y].rc_size;
869
870 rr->rr_col[VDEV_RAIDZ_P].rc_abd =
871 abd_alloc_linear(rr->rr_col[VDEV_RAIDZ_P].rc_size, B_TRUE);
872 rr->rr_col[VDEV_RAIDZ_Q].rc_abd =
873 abd_alloc_linear(rr->rr_col[VDEV_RAIDZ_Q].rc_size, B_TRUE);
874 rr->rr_col[x].rc_size = 0;
875 rr->rr_col[y].rc_size = 0;
876
877 vdev_raidz_generate_parity_pq(rr);
878
879 rr->rr_col[x].rc_size = xsize;
880 rr->rr_col[y].rc_size = ysize;
881
882 p = abd_to_buf(pdata);
883 q = abd_to_buf(qdata);
884 pxy = abd_to_buf(rr->rr_col[VDEV_RAIDZ_P].rc_abd);
885 qxy = abd_to_buf(rr->rr_col[VDEV_RAIDZ_Q].rc_abd);
886 xd = rr->rr_col[x].rc_abd;
887 yd = rr->rr_col[y].rc_abd;
888
889 /*
890 * We now have:
891 * Pxy = P + D_x + D_y
892 * Qxy = Q + 2^(ndevs - 1 - x) * D_x + 2^(ndevs - 1 - y) * D_y
893 *
894 * We can then solve for D_x:
895 * D_x = A * (P + Pxy) + B * (Q + Qxy)
896 * where
897 * A = 2^(x - y) * (2^(x - y) + 1)^-1
898 * B = 2^(ndevs - 1 - x) * (2^(x - y) + 1)^-1
899 *
900 * With D_x in hand, we can easily solve for D_y:
901 * D_y = P + Pxy + D_x
902 */
903
904 a = vdev_raidz_pow2[255 + x - y];
905 b = vdev_raidz_pow2[255 - (rr->rr_cols - 1 - x)];
906 tmp = 255 - vdev_raidz_log2[a ^ 1];
907
908 aexp = vdev_raidz_log2[vdev_raidz_exp2(a, tmp)];
909 bexp = vdev_raidz_log2[vdev_raidz_exp2(b, tmp)];
910
911 ASSERT3U(xsize, >=, ysize);
912 struct reconst_pq_struct rpq = { p, q, pxy, qxy, aexp, bexp };
913
914 (void) abd_iterate_func2(xd, yd, 0, 0, ysize,
915 vdev_raidz_reconst_pq_func, &rpq);
916 (void) abd_iterate_func(xd, ysize, xsize - ysize,
917 vdev_raidz_reconst_pq_tail_func, &rpq);
918
919 abd_free(rr->rr_col[VDEV_RAIDZ_P].rc_abd);
920 abd_free(rr->rr_col[VDEV_RAIDZ_Q].rc_abd);
921
922 /*
923 * Restore the saved parity data.
924 */
925 rr->rr_col[VDEV_RAIDZ_P].rc_abd = pdata;
926 rr->rr_col[VDEV_RAIDZ_Q].rc_abd = qdata;
927 }
928
929 /*
930 * In the general case of reconstruction, we must solve the system of linear
931 * equations defined by the coefficients used to generate parity as well as
932 * the contents of the data and parity disks. This can be expressed with
933 * vectors for the original data (D) and the actual data (d) and parity (p)
934 * and a matrix composed of the identity matrix (I) and a dispersal matrix (V):
935 *
936 * __ __ __ __
937 * | | __ __ | p_0 |
938 * | V | | D_0 | | p_m-1 |
939 * | | x | : | = | d_0 |
940 * | I | | D_n-1 | | : |
941 * | | ~~ ~~ | d_n-1 |
942 * ~~ ~~ ~~ ~~
943 *
944 * I is simply a square identity matrix of size n, and V is a vandermonde
945 * matrix defined by the coefficients we chose for the various parity columns
946 * (1, 2, 4). Note that these values were chosen both for simplicity, speedy
947 * computation as well as linear separability.
948 *
949 * __ __ __ __
950 * | 1 .. 1 1 1 | | p_0 |
951 * | 2^n-1 .. 4 2 1 | __ __ | : |
952 * | 4^n-1 .. 16 4 1 | | D_0 | | p_m-1 |
953 * | 1 .. 0 0 0 | | D_1 | | d_0 |
954 * | 0 .. 0 0 0 | x | D_2 | = | d_1 |
955 * | : : : : | | : | | d_2 |
956 * | 0 .. 1 0 0 | | D_n-1 | | : |
957 * | 0 .. 0 1 0 | ~~ ~~ | : |
958 * | 0 .. 0 0 1 | | d_n-1 |
959 * ~~ ~~ ~~ ~~
960 *
961 * Note that I, V, d, and p are known. To compute D, we must invert the
962 * matrix and use the known data and parity values to reconstruct the unknown
963 * data values. We begin by removing the rows in V|I and d|p that correspond
964 * to failed or missing columns; we then make V|I square (n x n) and d|p
965 * sized n by removing rows corresponding to unused parity from the bottom up
966 * to generate (V|I)' and (d|p)'. We can then generate the inverse of (V|I)'
967 * using Gauss-Jordan elimination. In the example below we use m=3 parity
968 * columns, n=8 data columns, with errors in d_1, d_2, and p_1:
969 * __ __
970 * | 1 1 1 1 1 1 1 1 |
971 * | 128 64 32 16 8 4 2 1 | <-----+-+-- missing disks
972 * | 19 205 116 29 64 16 4 1 | / /
973 * | 1 0 0 0 0 0 0 0 | / /
974 * | 0 1 0 0 0 0 0 0 | <--' /
975 * (V|I) = | 0 0 1 0 0 0 0 0 | <---'
976 * | 0 0 0 1 0 0 0 0 |
977 * | 0 0 0 0 1 0 0 0 |
978 * | 0 0 0 0 0 1 0 0 |
979 * | 0 0 0 0 0 0 1 0 |
980 * | 0 0 0 0 0 0 0 1 |
981 * ~~ ~~
982 * __ __
983 * | 1 1 1 1 1 1 1 1 |
984 * | 128 64 32 16 8 4 2 1 |
985 * | 19 205 116 29 64 16 4 1 |
986 * | 1 0 0 0 0 0 0 0 |
987 * | 0 1 0 0 0 0 0 0 |
988 * (V|I)' = | 0 0 1 0 0 0 0 0 |
989 * | 0 0 0 1 0 0 0 0 |
990 * | 0 0 0 0 1 0 0 0 |
991 * | 0 0 0 0 0 1 0 0 |
992 * | 0 0 0 0 0 0 1 0 |
993 * | 0 0 0 0 0 0 0 1 |
994 * ~~ ~~
995 *
996 * Here we employ Gauss-Jordan elimination to find the inverse of (V|I)'. We
997 * have carefully chosen the seed values 1, 2, and 4 to ensure that this
998 * matrix is not singular.
999 * __ __
1000 * | 1 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 |
1001 * | 19 205 116 29 64 16 4 1 0 1 0 0 0 0 0 0 |
1002 * | 1 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 |
1003 * | 0 0 0 1 0 0 0 0 0 0 0 1 0 0 0 0 |
1004 * | 0 0 0 0 1 0 0 0 0 0 0 0 1 0 0 0 |
1005 * | 0 0 0 0 0 1 0 0 0 0 0 0 0 1 0 0 |
1006 * | 0 0 0 0 0 0 1 0 0 0 0 0 0 0 1 0 |
1007 * | 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 1 |
1008 * ~~ ~~
1009 * __ __
1010 * | 1 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 |
1011 * | 1 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 |
1012 * | 19 205 116 29 64 16 4 1 0 1 0 0 0 0 0 0 |
1013 * | 0 0 0 1 0 0 0 0 0 0 0 1 0 0 0 0 |
1014 * | 0 0 0 0 1 0 0 0 0 0 0 0 1 0 0 0 |
1015 * | 0 0 0 0 0 1 0 0 0 0 0 0 0 1 0 0 |
1016 * | 0 0 0 0 0 0 1 0 0 0 0 0 0 0 1 0 |
1017 * | 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 1 |
1018 * ~~ ~~
1019 * __ __
1020 * | 1 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 |
1021 * | 0 1 1 0 0 0 0 0 1 0 1 1 1 1 1 1 |
1022 * | 0 205 116 0 0 0 0 0 0 1 19 29 64 16 4 1 |
1023 * | 0 0 0 1 0 0 0 0 0 0 0 1 0 0 0 0 |
1024 * | 0 0 0 0 1 0 0 0 0 0 0 0 1 0 0 0 |
1025 * | 0 0 0 0 0 1 0 0 0 0 0 0 0 1 0 0 |
1026 * | 0 0 0 0 0 0 1 0 0 0 0 0 0 0 1 0 |
1027 * | 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 1 |
1028 * ~~ ~~
1029 * __ __
1030 * | 1 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 |
1031 * | 0 1 1 0 0 0 0 0 1 0 1 1 1 1 1 1 |
1032 * | 0 0 185 0 0 0 0 0 205 1 222 208 141 221 201 204 |
1033 * | 0 0 0 1 0 0 0 0 0 0 0 1 0 0 0 0 |
1034 * | 0 0 0 0 1 0 0 0 0 0 0 0 1 0 0 0 |
1035 * | 0 0 0 0 0 1 0 0 0 0 0 0 0 1 0 0 |
1036 * | 0 0 0 0 0 0 1 0 0 0 0 0 0 0 1 0 |
1037 * | 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 1 |
1038 * ~~ ~~
1039 * __ __
1040 * | 1 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 |
1041 * | 0 1 1 0 0 0 0 0 1 0 1 1 1 1 1 1 |
1042 * | 0 0 1 0 0 0 0 0 166 100 4 40 158 168 216 209 |
1043 * | 0 0 0 1 0 0 0 0 0 0 0 1 0 0 0 0 |
1044 * | 0 0 0 0 1 0 0 0 0 0 0 0 1 0 0 0 |
1045 * | 0 0 0 0 0 1 0 0 0 0 0 0 0 1 0 0 |
1046 * | 0 0 0 0 0 0 1 0 0 0 0 0 0 0 1 0 |
1047 * | 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 1 |
1048 * ~~ ~~
1049 * __ __
1050 * | 1 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 |
1051 * | 0 1 0 0 0 0 0 0 167 100 5 41 159 169 217 208 |
1052 * | 0 0 1 0 0 0 0 0 166 100 4 40 158 168 216 209 |
1053 * | 0 0 0 1 0 0 0 0 0 0 0 1 0 0 0 0 |
1054 * | 0 0 0 0 1 0 0 0 0 0 0 0 1 0 0 0 |
1055 * | 0 0 0 0 0 1 0 0 0 0 0 0 0 1 0 0 |
1056 * | 0 0 0 0 0 0 1 0 0 0 0 0 0 0 1 0 |
1057 * | 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 1 |
1058 * ~~ ~~
1059 * __ __
1060 * | 0 0 1 0 0 0 0 0 |
1061 * | 167 100 5 41 159 169 217 208 |
1062 * | 166 100 4 40 158 168 216 209 |
1063 * (V|I)'^-1 = | 0 0 0 1 0 0 0 0 |
1064 * | 0 0 0 0 1 0 0 0 |
1065 * | 0 0 0 0 0 1 0 0 |
1066 * | 0 0 0 0 0 0 1 0 |
1067 * | 0 0 0 0 0 0 0 1 |
1068 * ~~ ~~
1069 *
1070 * We can then simply compute D = (V|I)'^-1 x (d|p)' to discover the values
1071 * of the missing data.
1072 *
1073 * As is apparent from the example above, the only non-trivial rows in the
1074 * inverse matrix correspond to the data disks that we're trying to
1075 * reconstruct. Indeed, those are the only rows we need as the others would
1076 * only be useful for reconstructing data known or assumed to be valid. For
1077 * that reason, we only build the coefficients in the rows that correspond to
1078 * targeted columns.
1079 */
1080
1081 static void
1082 vdev_raidz_matrix_init(raidz_row_t *rr, int n, int nmap, int *map,
1083 uint8_t **rows)
1084 {
1085 int i, j;
1086 int pow;
1087
1088 ASSERT(n == rr->rr_cols - rr->rr_firstdatacol);
1089
1090 /*
1091 * Fill in the missing rows of interest.
1092 */
1093 for (i = 0; i < nmap; i++) {
1094 ASSERT3S(0, <=, map[i]);
1095 ASSERT3S(map[i], <=, 2);
1096
1097 pow = map[i] * n;
1098 if (pow > 255)
1099 pow -= 255;
1100 ASSERT(pow <= 255);
1101
1102 for (j = 0; j < n; j++) {
1103 pow -= map[i];
1104 if (pow < 0)
1105 pow += 255;
1106 rows[i][j] = vdev_raidz_pow2[pow];
1107 }
1108 }
1109 }
1110
1111 static void
1112 vdev_raidz_matrix_invert(raidz_row_t *rr, int n, int nmissing, int *missing,
1113 uint8_t **rows, uint8_t **invrows, const uint8_t *used)
1114 {
1115 int i, j, ii, jj;
1116 uint8_t log;
1117
1118 /*
1119 * Assert that the first nmissing entries from the array of used
1120 * columns correspond to parity columns and that subsequent entries
1121 * correspond to data columns.
1122 */
1123 for (i = 0; i < nmissing; i++) {
1124 ASSERT3S(used[i], <, rr->rr_firstdatacol);
1125 }
1126 for (; i < n; i++) {
1127 ASSERT3S(used[i], >=, rr->rr_firstdatacol);
1128 }
1129
1130 /*
1131 * First initialize the storage where we'll compute the inverse rows.
1132 */
1133 for (i = 0; i < nmissing; i++) {
1134 for (j = 0; j < n; j++) {
1135 invrows[i][j] = (i == j) ? 1 : 0;
1136 }
1137 }
1138
1139 /*
1140 * Subtract all trivial rows from the rows of consequence.
1141 */
1142 for (i = 0; i < nmissing; i++) {
1143 for (j = nmissing; j < n; j++) {
1144 ASSERT3U(used[j], >=, rr->rr_firstdatacol);
1145 jj = used[j] - rr->rr_firstdatacol;
1146 ASSERT3S(jj, <, n);
1147 invrows[i][j] = rows[i][jj];
1148 rows[i][jj] = 0;
1149 }
1150 }
1151
1152 /*
1153 * For each of the rows of interest, we must normalize it and subtract
1154 * a multiple of it from the other rows.
1155 */
1156 for (i = 0; i < nmissing; i++) {
1157 for (j = 0; j < missing[i]; j++) {
1158 ASSERT0(rows[i][j]);
1159 }
1160 ASSERT3U(rows[i][missing[i]], !=, 0);
1161
1162 /*
1163 * Compute the inverse of the first element and multiply each
1164 * element in the row by that value.
1165 */
1166 log = 255 - vdev_raidz_log2[rows[i][missing[i]]];
1167
1168 for (j = 0; j < n; j++) {
1169 rows[i][j] = vdev_raidz_exp2(rows[i][j], log);
1170 invrows[i][j] = vdev_raidz_exp2(invrows[i][j], log);
1171 }
1172
1173 for (ii = 0; ii < nmissing; ii++) {
1174 if (i == ii)
1175 continue;
1176
1177 ASSERT3U(rows[ii][missing[i]], !=, 0);
1178
1179 log = vdev_raidz_log2[rows[ii][missing[i]]];
1180
1181 for (j = 0; j < n; j++) {
1182 rows[ii][j] ^=
1183 vdev_raidz_exp2(rows[i][j], log);
1184 invrows[ii][j] ^=
1185 vdev_raidz_exp2(invrows[i][j], log);
1186 }
1187 }
1188 }
1189
1190 /*
1191 * Verify that the data that is left in the rows are properly part of
1192 * an identity matrix.
1193 */
1194 for (i = 0; i < nmissing; i++) {
1195 for (j = 0; j < n; j++) {
1196 if (j == missing[i]) {
1197 ASSERT3U(rows[i][j], ==, 1);
1198 } else {
1199 ASSERT0(rows[i][j]);
1200 }
1201 }
1202 }
1203 }
1204
1205 static void
1206 vdev_raidz_matrix_reconstruct(raidz_row_t *rr, int n, int nmissing,
1207 int *missing, uint8_t **invrows, const uint8_t *used)
1208 {
1209 int i, j, x, cc, c;
1210 uint8_t *src;
1211 uint64_t ccount;
1212 uint8_t *dst[VDEV_RAIDZ_MAXPARITY] = { NULL };
1213 uint64_t dcount[VDEV_RAIDZ_MAXPARITY] = { 0 };
1214 uint8_t log = 0;
1215 uint8_t val;
1216 int ll;
1217 uint8_t *invlog[VDEV_RAIDZ_MAXPARITY];
1218 uint8_t *p, *pp;
1219 size_t psize;
1220
1221 psize = sizeof (invlog[0][0]) * n * nmissing;
1222 p = kmem_alloc(psize, KM_SLEEP);
1223
1224 for (pp = p, i = 0; i < nmissing; i++) {
1225 invlog[i] = pp;
1226 pp += n;
1227 }
1228
1229 for (i = 0; i < nmissing; i++) {
1230 for (j = 0; j < n; j++) {
1231 ASSERT3U(invrows[i][j], !=, 0);
1232 invlog[i][j] = vdev_raidz_log2[invrows[i][j]];
1233 }
1234 }
1235
1236 for (i = 0; i < n; i++) {
1237 c = used[i];
1238 ASSERT3U(c, <, rr->rr_cols);
1239
1240 ccount = rr->rr_col[c].rc_size;
1241 ASSERT(ccount >= rr->rr_col[missing[0]].rc_size || i > 0);
1242 if (ccount == 0)
1243 continue;
1244 src = abd_to_buf(rr->rr_col[c].rc_abd);
1245 for (j = 0; j < nmissing; j++) {
1246 cc = missing[j] + rr->rr_firstdatacol;
1247 ASSERT3U(cc, >=, rr->rr_firstdatacol);
1248 ASSERT3U(cc, <, rr->rr_cols);
1249 ASSERT3U(cc, !=, c);
1250
1251 dcount[j] = rr->rr_col[cc].rc_size;
1252 if (dcount[j] != 0)
1253 dst[j] = abd_to_buf(rr->rr_col[cc].rc_abd);
1254 }
1255
1256 for (x = 0; x < ccount; x++, src++) {
1257 if (*src != 0)
1258 log = vdev_raidz_log2[*src];
1259
1260 for (cc = 0; cc < nmissing; cc++) {
1261 if (x >= dcount[cc])
1262 continue;
1263
1264 if (*src == 0) {
1265 val = 0;
1266 } else {
1267 if ((ll = log + invlog[cc][i]) >= 255)
1268 ll -= 255;
1269 val = vdev_raidz_pow2[ll];
1270 }
1271
1272 if (i == 0)
1273 dst[cc][x] = val;
1274 else
1275 dst[cc][x] ^= val;
1276 }
1277 }
1278 }
1279
1280 kmem_free(p, psize);
1281 }
1282
1283 static void
1284 vdev_raidz_reconstruct_general(raidz_row_t *rr, int *tgts, int ntgts)
1285 {
1286 int n, i, c, t, tt;
1287 int nmissing_rows;
1288 int missing_rows[VDEV_RAIDZ_MAXPARITY];
1289 int parity_map[VDEV_RAIDZ_MAXPARITY];
1290 uint8_t *p, *pp;
1291 size_t psize;
1292 uint8_t *rows[VDEV_RAIDZ_MAXPARITY];
1293 uint8_t *invrows[VDEV_RAIDZ_MAXPARITY];
1294 uint8_t *used;
1295
1296 abd_t **bufs = NULL;
1297
1298 /*
1299 * Matrix reconstruction can't use scatter ABDs yet, so we allocate
1300 * temporary linear ABDs if any non-linear ABDs are found.
1301 */
1302 for (i = rr->rr_firstdatacol; i < rr->rr_cols; i++) {
1303 if (!abd_is_linear(rr->rr_col[i].rc_abd)) {
1304 bufs = kmem_alloc(rr->rr_cols * sizeof (abd_t *),
1305 KM_PUSHPAGE);
1306
1307 for (c = rr->rr_firstdatacol; c < rr->rr_cols; c++) {
1308 raidz_col_t *col = &rr->rr_col[c];
1309
1310 bufs[c] = col->rc_abd;
1311 if (bufs[c] != NULL) {
1312 col->rc_abd = abd_alloc_linear(
1313 col->rc_size, B_TRUE);
1314 abd_copy(col->rc_abd, bufs[c],
1315 col->rc_size);
1316 }
1317 }
1318
1319 break;
1320 }
1321 }
1322
1323 n = rr->rr_cols - rr->rr_firstdatacol;
1324
1325 /*
1326 * Figure out which data columns are missing.
1327 */
1328 nmissing_rows = 0;
1329 for (t = 0; t < ntgts; t++) {
1330 if (tgts[t] >= rr->rr_firstdatacol) {
1331 missing_rows[nmissing_rows++] =
1332 tgts[t] - rr->rr_firstdatacol;
1333 }
1334 }
1335
1336 /*
1337 * Figure out which parity columns to use to help generate the missing
1338 * data columns.
1339 */
1340 for (tt = 0, c = 0, i = 0; i < nmissing_rows; c++) {
1341 ASSERT(tt < ntgts);
1342 ASSERT(c < rr->rr_firstdatacol);
1343
1344 /*
1345 * Skip any targeted parity columns.
1346 */
1347 if (c == tgts[tt]) {
1348 tt++;
1349 continue;
1350 }
1351
1352 parity_map[i] = c;
1353 i++;
1354 }
1355
1356 psize = (sizeof (rows[0][0]) + sizeof (invrows[0][0])) *
1357 nmissing_rows * n + sizeof (used[0]) * n;
1358 p = kmem_alloc(psize, KM_SLEEP);
1359
1360 for (pp = p, i = 0; i < nmissing_rows; i++) {
1361 rows[i] = pp;
1362 pp += n;
1363 invrows[i] = pp;
1364 pp += n;
1365 }
1366 used = pp;
1367
1368 for (i = 0; i < nmissing_rows; i++) {
1369 used[i] = parity_map[i];
1370 }
1371
1372 for (tt = 0, c = rr->rr_firstdatacol; c < rr->rr_cols; c++) {
1373 if (tt < nmissing_rows &&
1374 c == missing_rows[tt] + rr->rr_firstdatacol) {
1375 tt++;
1376 continue;
1377 }
1378
1379 ASSERT3S(i, <, n);
1380 used[i] = c;
1381 i++;
1382 }
1383
1384 /*
1385 * Initialize the interesting rows of the matrix.
1386 */
1387 vdev_raidz_matrix_init(rr, n, nmissing_rows, parity_map, rows);
1388
1389 /*
1390 * Invert the matrix.
1391 */
1392 vdev_raidz_matrix_invert(rr, n, nmissing_rows, missing_rows, rows,
1393 invrows, used);
1394
1395 /*
1396 * Reconstruct the missing data using the generated matrix.
1397 */
1398 vdev_raidz_matrix_reconstruct(rr, n, nmissing_rows, missing_rows,
1399 invrows, used);
1400
1401 kmem_free(p, psize);
1402
1403 /*
1404 * copy back from temporary linear abds and free them
1405 */
1406 if (bufs) {
1407 for (c = rr->rr_firstdatacol; c < rr->rr_cols; c++) {
1408 raidz_col_t *col = &rr->rr_col[c];
1409
1410 if (bufs[c] != NULL) {
1411 abd_copy(bufs[c], col->rc_abd, col->rc_size);
1412 abd_free(col->rc_abd);
1413 }
1414 col->rc_abd = bufs[c];
1415 }
1416 kmem_free(bufs, rr->rr_cols * sizeof (abd_t *));
1417 }
1418 }
1419
1420 static void
1421 vdev_raidz_reconstruct_row(raidz_map_t *rm, raidz_row_t *rr,
1422 const int *t, int nt)
1423 {
1424 int tgts[VDEV_RAIDZ_MAXPARITY], *dt;
1425 int ntgts;
1426 int i, c, ret;
1427 int nbadparity, nbaddata;
1428 int parity_valid[VDEV_RAIDZ_MAXPARITY];
1429
1430 nbadparity = rr->rr_firstdatacol;
1431 nbaddata = rr->rr_cols - nbadparity;
1432 ntgts = 0;
1433 for (i = 0, c = 0; c < rr->rr_cols; c++) {
1434 if (c < rr->rr_firstdatacol)
1435 parity_valid[c] = B_FALSE;
1436
1437 if (i < nt && c == t[i]) {
1438 tgts[ntgts++] = c;
1439 i++;
1440 } else if (rr->rr_col[c].rc_error != 0) {
1441 tgts[ntgts++] = c;
1442 } else if (c >= rr->rr_firstdatacol) {
1443 nbaddata--;
1444 } else {
1445 parity_valid[c] = B_TRUE;
1446 nbadparity--;
1447 }
1448 }
1449
1450 ASSERT(ntgts >= nt);
1451 ASSERT(nbaddata >= 0);
1452 ASSERT(nbaddata + nbadparity == ntgts);
1453
1454 dt = &tgts[nbadparity];
1455
1456 /* Reconstruct using the new math implementation */
1457 ret = vdev_raidz_math_reconstruct(rm, rr, parity_valid, dt, nbaddata);
1458 if (ret != RAIDZ_ORIGINAL_IMPL)
1459 return;
1460
1461 /*
1462 * See if we can use any of our optimized reconstruction routines.
1463 */
1464 switch (nbaddata) {
1465 case 1:
1466 if (parity_valid[VDEV_RAIDZ_P]) {
1467 vdev_raidz_reconstruct_p(rr, dt, 1);
1468 return;
1469 }
1470
1471 ASSERT(rr->rr_firstdatacol > 1);
1472
1473 if (parity_valid[VDEV_RAIDZ_Q]) {
1474 vdev_raidz_reconstruct_q(rr, dt, 1);
1475 return;
1476 }
1477
1478 ASSERT(rr->rr_firstdatacol > 2);
1479 break;
1480
1481 case 2:
1482 ASSERT(rr->rr_firstdatacol > 1);
1483
1484 if (parity_valid[VDEV_RAIDZ_P] &&
1485 parity_valid[VDEV_RAIDZ_Q]) {
1486 vdev_raidz_reconstruct_pq(rr, dt, 2);
1487 return;
1488 }
1489
1490 ASSERT(rr->rr_firstdatacol > 2);
1491
1492 break;
1493 }
1494
1495 vdev_raidz_reconstruct_general(rr, tgts, ntgts);
1496 }
1497
1498 static int
1499 vdev_raidz_open(vdev_t *vd, uint64_t *asize, uint64_t *max_asize,
1500 uint64_t *logical_ashift, uint64_t *physical_ashift)
1501 {
1502 vdev_raidz_t *vdrz = vd->vdev_tsd;
1503 uint64_t nparity = vdrz->vd_nparity;
1504 int c;
1505 int lasterror = 0;
1506 int numerrors = 0;
1507
1508 ASSERT(nparity > 0);
1509
1510 if (nparity > VDEV_RAIDZ_MAXPARITY ||
1511 vd->vdev_children < nparity + 1) {
1512 vd->vdev_stat.vs_aux = VDEV_AUX_BAD_LABEL;
1513 return (SET_ERROR(EINVAL));
1514 }
1515
1516 vdev_open_children(vd);
1517
1518 for (c = 0; c < vd->vdev_children; c++) {
1519 vdev_t *cvd = vd->vdev_child[c];
1520
1521 if (cvd->vdev_open_error != 0) {
1522 lasterror = cvd->vdev_open_error;
1523 numerrors++;
1524 continue;
1525 }
1526
1527 *asize = MIN(*asize - 1, cvd->vdev_asize - 1) + 1;
1528 *max_asize = MIN(*max_asize - 1, cvd->vdev_max_asize - 1) + 1;
1529 *logical_ashift = MAX(*logical_ashift, cvd->vdev_ashift);
1530 }
1531 for (c = 0; c < vd->vdev_children; c++) {
1532 vdev_t *cvd = vd->vdev_child[c];
1533
1534 if (cvd->vdev_open_error != 0)
1535 continue;
1536 *physical_ashift = vdev_best_ashift(*logical_ashift,
1537 *physical_ashift, cvd->vdev_physical_ashift);
1538 }
1539
1540 *asize *= vd->vdev_children;
1541 *max_asize *= vd->vdev_children;
1542
1543 if (numerrors > nparity) {
1544 vd->vdev_stat.vs_aux = VDEV_AUX_NO_REPLICAS;
1545 return (lasterror);
1546 }
1547
1548 return (0);
1549 }
1550
1551 static void
1552 vdev_raidz_close(vdev_t *vd)
1553 {
1554 for (int c = 0; c < vd->vdev_children; c++) {
1555 if (vd->vdev_child[c] != NULL)
1556 vdev_close(vd->vdev_child[c]);
1557 }
1558 }
1559
1560 static uint64_t
1561 vdev_raidz_asize(vdev_t *vd, uint64_t psize)
1562 {
1563 vdev_raidz_t *vdrz = vd->vdev_tsd;
1564 uint64_t asize;
1565 uint64_t ashift = vd->vdev_top->vdev_ashift;
1566 uint64_t cols = vdrz->vd_logical_width;
1567 uint64_t nparity = vdrz->vd_nparity;
1568
1569 asize = ((psize - 1) >> ashift) + 1;
1570 asize += nparity * ((asize + cols - nparity - 1) / (cols - nparity));
1571 asize = roundup(asize, nparity + 1) << ashift;
1572
1573 return (asize);
1574 }
1575
1576 /*
1577 * The allocatable space for a raidz vdev is N * sizeof(smallest child)
1578 * so each child must provide at least 1/Nth of its asize.
1579 */
1580 static uint64_t
1581 vdev_raidz_min_asize(vdev_t *vd)
1582 {
1583 return ((vd->vdev_min_asize + vd->vdev_children - 1) /
1584 vd->vdev_children);
1585 }
1586
1587 void
1588 vdev_raidz_child_done(zio_t *zio)
1589 {
1590 raidz_col_t *rc = zio->io_private;
1591
1592 ASSERT3P(rc->rc_abd, !=, NULL);
1593 rc->rc_error = zio->io_error;
1594 rc->rc_tried = 1;
1595 rc->rc_skipped = 0;
1596 }
1597
1598 static void
1599 vdev_raidz_io_verify(vdev_t *vd, raidz_row_t *rr, int col)
1600 {
1601 #ifdef ZFS_DEBUG
1602 vdev_t *tvd = vd->vdev_top;
1603
1604 range_seg64_t logical_rs, physical_rs, remain_rs;
1605 logical_rs.rs_start = rr->rr_offset;
1606 logical_rs.rs_end = logical_rs.rs_start +
1607 vdev_raidz_asize(vd, rr->rr_size);
1608
1609 raidz_col_t *rc = &rr->rr_col[col];
1610 vdev_t *cvd = vd->vdev_child[rc->rc_devidx];
1611
1612 vdev_xlate(cvd, &logical_rs, &physical_rs, &remain_rs);
1613 ASSERT(vdev_xlate_is_empty(&remain_rs));
1614 ASSERT3U(rc->rc_offset, ==, physical_rs.rs_start);
1615 ASSERT3U(rc->rc_offset, <, physical_rs.rs_end);
1616 /*
1617 * It would be nice to assert that rs_end is equal
1618 * to rc_offset + rc_size but there might be an
1619 * optional I/O at the end that is not accounted in
1620 * rc_size.
1621 */
1622 if (physical_rs.rs_end > rc->rc_offset + rc->rc_size) {
1623 ASSERT3U(physical_rs.rs_end, ==, rc->rc_offset +
1624 rc->rc_size + (1 << tvd->vdev_ashift));
1625 } else {
1626 ASSERT3U(physical_rs.rs_end, ==, rc->rc_offset + rc->rc_size);
1627 }
1628 #endif
1629 }
1630
1631 static void
1632 vdev_raidz_io_start_write(zio_t *zio, raidz_row_t *rr, uint64_t ashift)
1633 {
1634 vdev_t *vd = zio->io_vd;
1635 raidz_map_t *rm = zio->io_vsd;
1636
1637 vdev_raidz_generate_parity_row(rm, rr);
1638
1639 for (int c = 0; c < rr->rr_scols; c++) {
1640 raidz_col_t *rc = &rr->rr_col[c];
1641 vdev_t *cvd = vd->vdev_child[rc->rc_devidx];
1642
1643 /* Verify physical to logical translation */
1644 vdev_raidz_io_verify(vd, rr, c);
1645
1646 if (rc->rc_size > 0) {
1647 ASSERT3P(rc->rc_abd, !=, NULL);
1648 zio_nowait(zio_vdev_child_io(zio, NULL, cvd,
1649 rc->rc_offset, rc->rc_abd,
1650 abd_get_size(rc->rc_abd), zio->io_type,
1651 zio->io_priority, 0, vdev_raidz_child_done, rc));
1652 } else {
1653 /*
1654 * Generate optional write for skip sector to improve
1655 * aggregation contiguity.
1656 */
1657 ASSERT3P(rc->rc_abd, ==, NULL);
1658 zio_nowait(zio_vdev_child_io(zio, NULL, cvd,
1659 rc->rc_offset, NULL, 1ULL << ashift,
1660 zio->io_type, zio->io_priority,
1661 ZIO_FLAG_NODATA | ZIO_FLAG_OPTIONAL, NULL,
1662 NULL));
1663 }
1664 }
1665 }
1666
1667 static void
1668 vdev_raidz_io_start_read(zio_t *zio, raidz_row_t *rr)
1669 {
1670 vdev_t *vd = zio->io_vd;
1671
1672 /*
1673 * Iterate over the columns in reverse order so that we hit the parity
1674 * last -- any errors along the way will force us to read the parity.
1675 */
1676 for (int c = rr->rr_cols - 1; c >= 0; c--) {
1677 raidz_col_t *rc = &rr->rr_col[c];
1678 if (rc->rc_size == 0)
1679 continue;
1680 vdev_t *cvd = vd->vdev_child[rc->rc_devidx];
1681 if (!vdev_readable(cvd)) {
1682 if (c >= rr->rr_firstdatacol)
1683 rr->rr_missingdata++;
1684 else
1685 rr->rr_missingparity++;
1686 rc->rc_error = SET_ERROR(ENXIO);
1687 rc->rc_tried = 1; /* don't even try */
1688 rc->rc_skipped = 1;
1689 continue;
1690 }
1691 if (vdev_dtl_contains(cvd, DTL_MISSING, zio->io_txg, 1)) {
1692 if (c >= rr->rr_firstdatacol)
1693 rr->rr_missingdata++;
1694 else
1695 rr->rr_missingparity++;
1696 rc->rc_error = SET_ERROR(ESTALE);
1697 rc->rc_skipped = 1;
1698 continue;
1699 }
1700 if (c >= rr->rr_firstdatacol || rr->rr_missingdata > 0 ||
1701 (zio->io_flags & (ZIO_FLAG_SCRUB | ZIO_FLAG_RESILVER))) {
1702 zio_nowait(zio_vdev_child_io(zio, NULL, cvd,
1703 rc->rc_offset, rc->rc_abd, rc->rc_size,
1704 zio->io_type, zio->io_priority, 0,
1705 vdev_raidz_child_done, rc));
1706 }
1707 }
1708 }
1709
1710 /*
1711 * Start an IO operation on a RAIDZ VDev
1712 *
1713 * Outline:
1714 * - For write operations:
1715 * 1. Generate the parity data
1716 * 2. Create child zio write operations to each column's vdev, for both
1717 * data and parity.
1718 * 3. If the column skips any sectors for padding, create optional dummy
1719 * write zio children for those areas to improve aggregation continuity.
1720 * - For read operations:
1721 * 1. Create child zio read operations to each data column's vdev to read
1722 * the range of data required for zio.
1723 * 2. If this is a scrub or resilver operation, or if any of the data
1724 * vdevs have had errors, then create zio read operations to the parity
1725 * columns' VDevs as well.
1726 */
1727 static void
1728 vdev_raidz_io_start(zio_t *zio)
1729 {
1730 vdev_t *vd = zio->io_vd;
1731 vdev_t *tvd = vd->vdev_top;
1732 vdev_raidz_t *vdrz = vd->vdev_tsd;
1733
1734 raidz_map_t *rm = vdev_raidz_map_alloc(zio, tvd->vdev_ashift,
1735 vdrz->vd_logical_width, vdrz->vd_nparity);
1736 zio->io_vsd = rm;
1737 zio->io_vsd_ops = &vdev_raidz_vsd_ops;
1738
1739 /*
1740 * Until raidz expansion is implemented all maps for a raidz vdev
1741 * contain a single row.
1742 */
1743 ASSERT3U(rm->rm_nrows, ==, 1);
1744 raidz_row_t *rr = rm->rm_row[0];
1745
1746 if (zio->io_type == ZIO_TYPE_WRITE) {
1747 vdev_raidz_io_start_write(zio, rr, tvd->vdev_ashift);
1748 } else {
1749 ASSERT(zio->io_type == ZIO_TYPE_READ);
1750 vdev_raidz_io_start_read(zio, rr);
1751 }
1752
1753 zio_execute(zio);
1754 }
1755
1756 /*
1757 * Report a checksum error for a child of a RAID-Z device.
1758 */
1759 void
1760 vdev_raidz_checksum_error(zio_t *zio, raidz_col_t *rc, abd_t *bad_data)
1761 {
1762 vdev_t *vd = zio->io_vd->vdev_child[rc->rc_devidx];
1763
1764 if (!(zio->io_flags & ZIO_FLAG_SPECULATIVE) &&
1765 zio->io_priority != ZIO_PRIORITY_REBUILD) {
1766 zio_bad_cksum_t zbc;
1767 raidz_map_t *rm = zio->io_vsd;
1768
1769 zbc.zbc_has_cksum = 0;
1770 zbc.zbc_injected = rm->rm_ecksuminjected;
1771
1772 mutex_enter(&vd->vdev_stat_lock);
1773 vd->vdev_stat.vs_checksum_errors++;
1774 mutex_exit(&vd->vdev_stat_lock);
1775 (void) zfs_ereport_post_checksum(zio->io_spa, vd,
1776 &zio->io_bookmark, zio, rc->rc_offset, rc->rc_size,
1777 rc->rc_abd, bad_data, &zbc);
1778 }
1779 }
1780
1781 /*
1782 * We keep track of whether or not there were any injected errors, so that
1783 * any ereports we generate can note it.
1784 */
1785 static int
1786 raidz_checksum_verify(zio_t *zio)
1787 {
1788 zio_bad_cksum_t zbc = {0};
1789 raidz_map_t *rm = zio->io_vsd;
1790
1791 int ret = zio_checksum_error(zio, &zbc);
1792 if (ret != 0 && zbc.zbc_injected != 0)
1793 rm->rm_ecksuminjected = 1;
1794
1795 return (ret);
1796 }
1797
1798 /*
1799 * Generate the parity from the data columns. If we tried and were able to
1800 * read the parity without error, verify that the generated parity matches the
1801 * data we read. If it doesn't, we fire off a checksum error. Return the
1802 * number of such failures.
1803 */
1804 static int
1805 raidz_parity_verify(zio_t *zio, raidz_row_t *rr)
1806 {
1807 abd_t *orig[VDEV_RAIDZ_MAXPARITY];
1808 int c, ret = 0;
1809 raidz_map_t *rm = zio->io_vsd;
1810 raidz_col_t *rc;
1811
1812 blkptr_t *bp = zio->io_bp;
1813 enum zio_checksum checksum = (bp == NULL ? zio->io_prop.zp_checksum :
1814 (BP_IS_GANG(bp) ? ZIO_CHECKSUM_GANG_HEADER : BP_GET_CHECKSUM(bp)));
1815
1816 if (checksum == ZIO_CHECKSUM_NOPARITY)
1817 return (ret);
1818
1819 for (c = 0; c < rr->rr_firstdatacol; c++) {
1820 rc = &rr->rr_col[c];
1821 if (!rc->rc_tried || rc->rc_error != 0)
1822 continue;
1823
1824 orig[c] = rc->rc_abd;
1825 ASSERT3U(abd_get_size(rc->rc_abd), ==, rc->rc_size);
1826 rc->rc_abd = abd_alloc_linear(rc->rc_size, B_FALSE);
1827 }
1828
1829 /*
1830 * Verify any empty sectors are zero filled to ensure the parity
1831 * is calculated correctly even if these non-data sectors are damaged.
1832 */
1833 if (rr->rr_nempty && rr->rr_abd_empty != NULL)
1834 ret += vdev_draid_map_verify_empty(zio, rr);
1835
1836 /*
1837 * Regenerates parity even for !tried||rc_error!=0 columns. This
1838 * isn't harmful but it does have the side effect of fixing stuff
1839 * we didn't realize was necessary (i.e. even if we return 0).
1840 */
1841 vdev_raidz_generate_parity_row(rm, rr);
1842
1843 for (c = 0; c < rr->rr_firstdatacol; c++) {
1844 rc = &rr->rr_col[c];
1845
1846 if (!rc->rc_tried || rc->rc_error != 0)
1847 continue;
1848
1849 if (abd_cmp(orig[c], rc->rc_abd) != 0) {
1850 vdev_raidz_checksum_error(zio, rc, orig[c]);
1851 rc->rc_error = SET_ERROR(ECKSUM);
1852 ret++;
1853 }
1854 abd_free(orig[c]);
1855 }
1856
1857 return (ret);
1858 }
1859
1860 static int
1861 vdev_raidz_worst_error(raidz_row_t *rr)
1862 {
1863 int error = 0;
1864
1865 for (int c = 0; c < rr->rr_cols; c++)
1866 error = zio_worst_error(error, rr->rr_col[c].rc_error);
1867
1868 return (error);
1869 }
1870
1871 static void
1872 vdev_raidz_io_done_verified(zio_t *zio, raidz_row_t *rr)
1873 {
1874 int unexpected_errors = 0;
1875 int parity_errors = 0;
1876 int parity_untried = 0;
1877 int data_errors = 0;
1878
1879 ASSERT3U(zio->io_type, ==, ZIO_TYPE_READ);
1880
1881 for (int c = 0; c < rr->rr_cols; c++) {
1882 raidz_col_t *rc = &rr->rr_col[c];
1883
1884 if (rc->rc_error) {
1885 if (c < rr->rr_firstdatacol)
1886 parity_errors++;
1887 else
1888 data_errors++;
1889
1890 if (!rc->rc_skipped)
1891 unexpected_errors++;
1892 } else if (c < rr->rr_firstdatacol && !rc->rc_tried) {
1893 parity_untried++;
1894 }
1895
1896 if (rc->rc_force_repair)
1897 unexpected_errors++;
1898 }
1899
1900 /*
1901 * If we read more parity disks than were used for
1902 * reconstruction, confirm that the other parity disks produced
1903 * correct data.
1904 *
1905 * Note that we also regenerate parity when resilvering so we
1906 * can write it out to failed devices later.
1907 */
1908 if (parity_errors + parity_untried <
1909 rr->rr_firstdatacol - data_errors ||
1910 (zio->io_flags & ZIO_FLAG_RESILVER)) {
1911 int n = raidz_parity_verify(zio, rr);
1912 unexpected_errors += n;
1913 }
1914
1915 if (zio->io_error == 0 && spa_writeable(zio->io_spa) &&
1916 (unexpected_errors > 0 || (zio->io_flags & ZIO_FLAG_RESILVER))) {
1917 /*
1918 * Use the good data we have in hand to repair damaged children.
1919 */
1920 for (int c = 0; c < rr->rr_cols; c++) {
1921 raidz_col_t *rc = &rr->rr_col[c];
1922 vdev_t *vd = zio->io_vd;
1923 vdev_t *cvd = vd->vdev_child[rc->rc_devidx];
1924
1925 if (!rc->rc_allow_repair) {
1926 continue;
1927 } else if (!rc->rc_force_repair &&
1928 (rc->rc_error == 0 || rc->rc_size == 0)) {
1929 continue;
1930 }
1931
1932 zio_nowait(zio_vdev_child_io(zio, NULL, cvd,
1933 rc->rc_offset, rc->rc_abd, rc->rc_size,
1934 ZIO_TYPE_WRITE,
1935 zio->io_priority == ZIO_PRIORITY_REBUILD ?
1936 ZIO_PRIORITY_REBUILD : ZIO_PRIORITY_ASYNC_WRITE,
1937 ZIO_FLAG_IO_REPAIR | (unexpected_errors ?
1938 ZIO_FLAG_SELF_HEAL : 0), NULL, NULL));
1939 }
1940 }
1941 }
1942
1943 static void
1944 raidz_restore_orig_data(raidz_map_t *rm)
1945 {
1946 for (int i = 0; i < rm->rm_nrows; i++) {
1947 raidz_row_t *rr = rm->rm_row[i];
1948 for (int c = 0; c < rr->rr_cols; c++) {
1949 raidz_col_t *rc = &rr->rr_col[c];
1950 if (rc->rc_need_orig_restore) {
1951 abd_copy(rc->rc_abd,
1952 rc->rc_orig_data, rc->rc_size);
1953 rc->rc_need_orig_restore = B_FALSE;
1954 }
1955 }
1956 }
1957 }
1958
1959 /*
1960 * returns EINVAL if reconstruction of the block will not be possible
1961 * returns ECKSUM if this specific reconstruction failed
1962 * returns 0 on successful reconstruction
1963 */
1964 static int
1965 raidz_reconstruct(zio_t *zio, int *ltgts, int ntgts, int nparity)
1966 {
1967 raidz_map_t *rm = zio->io_vsd;
1968
1969 /* Reconstruct each row */
1970 for (int r = 0; r < rm->rm_nrows; r++) {
1971 raidz_row_t *rr = rm->rm_row[r];
1972 int my_tgts[VDEV_RAIDZ_MAXPARITY]; /* value is child id */
1973 int t = 0;
1974 int dead = 0;
1975 int dead_data = 0;
1976
1977 for (int c = 0; c < rr->rr_cols; c++) {
1978 raidz_col_t *rc = &rr->rr_col[c];
1979 ASSERT0(rc->rc_need_orig_restore);
1980 if (rc->rc_error != 0) {
1981 dead++;
1982 if (c >= nparity)
1983 dead_data++;
1984 continue;
1985 }
1986 if (rc->rc_size == 0)
1987 continue;
1988 for (int lt = 0; lt < ntgts; lt++) {
1989 if (rc->rc_devidx == ltgts[lt]) {
1990 if (rc->rc_orig_data == NULL) {
1991 rc->rc_orig_data =
1992 abd_alloc_linear(
1993 rc->rc_size, B_TRUE);
1994 abd_copy(rc->rc_orig_data,
1995 rc->rc_abd, rc->rc_size);
1996 }
1997 rc->rc_need_orig_restore = B_TRUE;
1998
1999 dead++;
2000 if (c >= nparity)
2001 dead_data++;
2002 my_tgts[t++] = c;
2003 break;
2004 }
2005 }
2006 }
2007 if (dead > nparity) {
2008 /* reconstruction not possible */
2009 raidz_restore_orig_data(rm);
2010 return (EINVAL);
2011 }
2012 if (dead_data > 0)
2013 vdev_raidz_reconstruct_row(rm, rr, my_tgts, t);
2014 }
2015
2016 /* Check for success */
2017 if (raidz_checksum_verify(zio) == 0) {
2018
2019 /* Reconstruction succeeded - report errors */
2020 for (int i = 0; i < rm->rm_nrows; i++) {
2021 raidz_row_t *rr = rm->rm_row[i];
2022
2023 for (int c = 0; c < rr->rr_cols; c++) {
2024 raidz_col_t *rc = &rr->rr_col[c];
2025 if (rc->rc_need_orig_restore) {
2026 /*
2027 * Note: if this is a parity column,
2028 * we don't really know if it's wrong.
2029 * We need to let
2030 * vdev_raidz_io_done_verified() check
2031 * it, and if we set rc_error, it will
2032 * think that it is a "known" error
2033 * that doesn't need to be checked
2034 * or corrected.
2035 */
2036 if (rc->rc_error == 0 &&
2037 c >= rr->rr_firstdatacol) {
2038 vdev_raidz_checksum_error(zio,
2039 rc, rc->rc_orig_data);
2040 rc->rc_error =
2041 SET_ERROR(ECKSUM);
2042 }
2043 rc->rc_need_orig_restore = B_FALSE;
2044 }
2045 }
2046
2047 vdev_raidz_io_done_verified(zio, rr);
2048 }
2049
2050 zio_checksum_verified(zio);
2051
2052 return (0);
2053 }
2054
2055 /* Reconstruction failed - restore original data */
2056 raidz_restore_orig_data(rm);
2057 return (ECKSUM);
2058 }
2059
2060 /*
2061 * Iterate over all combinations of N bad vdevs and attempt a reconstruction.
2062 * Note that the algorithm below is non-optimal because it doesn't take into
2063 * account how reconstruction is actually performed. For example, with
2064 * triple-parity RAID-Z the reconstruction procedure is the same if column 4
2065 * is targeted as invalid as if columns 1 and 4 are targeted since in both
2066 * cases we'd only use parity information in column 0.
2067 *
2068 * The order that we find the various possible combinations of failed
2069 * disks is dictated by these rules:
2070 * - Examine each "slot" (the "i" in tgts[i])
2071 * - Try to increment this slot (tgts[i] = tgts[i] + 1)
2072 * - if we can't increment because it runs into the next slot,
2073 * reset our slot to the minimum, and examine the next slot
2074 *
2075 * For example, with a 6-wide RAIDZ3, and no known errors (so we have to choose
2076 * 3 columns to reconstruct), we will generate the following sequence:
2077 *
2078 * STATE ACTION
2079 * 0 1 2 special case: skip since these are all parity
2080 * 0 1 3 first slot: reset to 0; middle slot: increment to 2
2081 * 0 2 3 first slot: increment to 1
2082 * 1 2 3 first: reset to 0; middle: reset to 1; last: increment to 4
2083 * 0 1 4 first: reset to 0; middle: increment to 2
2084 * 0 2 4 first: increment to 1
2085 * 1 2 4 first: reset to 0; middle: increment to 3
2086 * 0 3 4 first: increment to 1
2087 * 1 3 4 first: increment to 2
2088 * 2 3 4 first: reset to 0; middle: reset to 1; last: increment to 5
2089 * 0 1 5 first: reset to 0; middle: increment to 2
2090 * 0 2 5 first: increment to 1
2091 * 1 2 5 first: reset to 0; middle: increment to 3
2092 * 0 3 5 first: increment to 1
2093 * 1 3 5 first: increment to 2
2094 * 2 3 5 first: reset to 0; middle: increment to 4
2095 * 0 4 5 first: increment to 1
2096 * 1 4 5 first: increment to 2
2097 * 2 4 5 first: increment to 3
2098 * 3 4 5 done
2099 *
2100 * This strategy works for dRAID but is less efficient when there are a large
2101 * number of child vdevs and therefore permutations to check. Furthermore,
2102 * since the raidz_map_t rows likely do not overlap reconstruction would be
2103 * possible as long as there are no more than nparity data errors per row.
2104 * These additional permutations are not currently checked but could be as
2105 * a future improvement.
2106 */
2107 static int
2108 vdev_raidz_combrec(zio_t *zio)
2109 {
2110 int nparity = vdev_get_nparity(zio->io_vd);
2111 raidz_map_t *rm = zio->io_vsd;
2112
2113 /* Check if there's enough data to attempt reconstrution. */
2114 for (int i = 0; i < rm->rm_nrows; i++) {
2115 raidz_row_t *rr = rm->rm_row[i];
2116 int total_errors = 0;
2117
2118 for (int c = 0; c < rr->rr_cols; c++) {
2119 if (rr->rr_col[c].rc_error)
2120 total_errors++;
2121 }
2122
2123 if (total_errors > nparity)
2124 return (vdev_raidz_worst_error(rr));
2125 }
2126
2127 for (int num_failures = 1; num_failures <= nparity; num_failures++) {
2128 int tstore[VDEV_RAIDZ_MAXPARITY + 2];
2129 int *ltgts = &tstore[1]; /* value is logical child ID */
2130
2131 /* Determine number of logical children, n */
2132 int n = zio->io_vd->vdev_children;
2133
2134 ASSERT3U(num_failures, <=, nparity);
2135 ASSERT3U(num_failures, <=, VDEV_RAIDZ_MAXPARITY);
2136
2137 /* Handle corner cases in combrec logic */
2138 ltgts[-1] = -1;
2139 for (int i = 0; i < num_failures; i++) {
2140 ltgts[i] = i;
2141 }
2142 ltgts[num_failures] = n;
2143
2144 for (;;) {
2145 int err = raidz_reconstruct(zio, ltgts, num_failures,
2146 nparity);
2147 if (err == EINVAL) {
2148 /*
2149 * Reconstruction not possible with this #
2150 * failures; try more failures.
2151 */
2152 break;
2153 } else if (err == 0)
2154 return (0);
2155
2156 /* Compute next targets to try */
2157 for (int t = 0; ; t++) {
2158 ASSERT3U(t, <, num_failures);
2159 ltgts[t]++;
2160 if (ltgts[t] == n) {
2161 /* try more failures */
2162 ASSERT3U(t, ==, num_failures - 1);
2163 break;
2164 }
2165
2166 ASSERT3U(ltgts[t], <, n);
2167 ASSERT3U(ltgts[t], <=, ltgts[t + 1]);
2168
2169 /*
2170 * If that spot is available, we're done here.
2171 * Try the next combination.
2172 */
2173 if (ltgts[t] != ltgts[t + 1])
2174 break;
2175
2176 /*
2177 * Otherwise, reset this tgt to the minimum,
2178 * and move on to the next tgt.
2179 */
2180 ltgts[t] = ltgts[t - 1] + 1;
2181 ASSERT3U(ltgts[t], ==, t);
2182 }
2183
2184 /* Increase the number of failures and keep trying. */
2185 if (ltgts[num_failures - 1] == n)
2186 break;
2187 }
2188 }
2189
2190 return (ECKSUM);
2191 }
2192
2193 void
2194 vdev_raidz_reconstruct(raidz_map_t *rm, const int *t, int nt)
2195 {
2196 for (uint64_t row = 0; row < rm->rm_nrows; row++) {
2197 raidz_row_t *rr = rm->rm_row[row];
2198 vdev_raidz_reconstruct_row(rm, rr, t, nt);
2199 }
2200 }
2201
2202 /*
2203 * Complete a write IO operation on a RAIDZ VDev
2204 *
2205 * Outline:
2206 * 1. Check for errors on the child IOs.
2207 * 2. Return, setting an error code if too few child VDevs were written
2208 * to reconstruct the data later. Note that partial writes are
2209 * considered successful if they can be reconstructed at all.
2210 */
2211 static void
2212 vdev_raidz_io_done_write_impl(zio_t *zio, raidz_row_t *rr)
2213 {
2214 int total_errors = 0;
2215
2216 ASSERT3U(rr->rr_missingparity, <=, rr->rr_firstdatacol);
2217 ASSERT3U(rr->rr_missingdata, <=, rr->rr_cols - rr->rr_firstdatacol);
2218 ASSERT3U(zio->io_type, ==, ZIO_TYPE_WRITE);
2219
2220 for (int c = 0; c < rr->rr_cols; c++) {
2221 raidz_col_t *rc = &rr->rr_col[c];
2222
2223 if (rc->rc_error) {
2224 ASSERT(rc->rc_error != ECKSUM); /* child has no bp */
2225
2226 total_errors++;
2227 }
2228 }
2229
2230 /*
2231 * Treat partial writes as a success. If we couldn't write enough
2232 * columns to reconstruct the data, the I/O failed. Otherwise,
2233 * good enough.
2234 *
2235 * Now that we support write reallocation, it would be better
2236 * to treat partial failure as real failure unless there are
2237 * no non-degraded top-level vdevs left, and not update DTLs
2238 * if we intend to reallocate.
2239 */
2240 if (total_errors > rr->rr_firstdatacol) {
2241 zio->io_error = zio_worst_error(zio->io_error,
2242 vdev_raidz_worst_error(rr));
2243 }
2244 }
2245
2246 static void
2247 vdev_raidz_io_done_reconstruct_known_missing(zio_t *zio, raidz_map_t *rm,
2248 raidz_row_t *rr)
2249 {
2250 int parity_errors = 0;
2251 int parity_untried = 0;
2252 int data_errors = 0;
2253 int total_errors = 0;
2254
2255 ASSERT3U(rr->rr_missingparity, <=, rr->rr_firstdatacol);
2256 ASSERT3U(rr->rr_missingdata, <=, rr->rr_cols - rr->rr_firstdatacol);
2257 ASSERT3U(zio->io_type, ==, ZIO_TYPE_READ);
2258
2259 for (int c = 0; c < rr->rr_cols; c++) {
2260 raidz_col_t *rc = &rr->rr_col[c];
2261
2262 /*
2263 * If scrubbing and a replacing/sparing child vdev determined
2264 * that not all of its children have an identical copy of the
2265 * data, then clear the error so the column is treated like
2266 * any other read and force a repair to correct the damage.
2267 */
2268 if (rc->rc_error == ECKSUM) {
2269 ASSERT(zio->io_flags & ZIO_FLAG_SCRUB);
2270 vdev_raidz_checksum_error(zio, rc, rc->rc_abd);
2271 rc->rc_force_repair = 1;
2272 rc->rc_error = 0;
2273 }
2274
2275 if (rc->rc_error) {
2276 if (c < rr->rr_firstdatacol)
2277 parity_errors++;
2278 else
2279 data_errors++;
2280
2281 total_errors++;
2282 } else if (c < rr->rr_firstdatacol && !rc->rc_tried) {
2283 parity_untried++;
2284 }
2285 }
2286
2287 /*
2288 * If there were data errors and the number of errors we saw was
2289 * correctable -- less than or equal to the number of parity disks read
2290 * -- reconstruct based on the missing data.
2291 */
2292 if (data_errors != 0 &&
2293 total_errors <= rr->rr_firstdatacol - parity_untried) {
2294 /*
2295 * We either attempt to read all the parity columns or
2296 * none of them. If we didn't try to read parity, we
2297 * wouldn't be here in the correctable case. There must
2298 * also have been fewer parity errors than parity
2299 * columns or, again, we wouldn't be in this code path.
2300 */
2301 ASSERT(parity_untried == 0);
2302 ASSERT(parity_errors < rr->rr_firstdatacol);
2303
2304 /*
2305 * Identify the data columns that reported an error.
2306 */
2307 int n = 0;
2308 int tgts[VDEV_RAIDZ_MAXPARITY];
2309 for (int c = rr->rr_firstdatacol; c < rr->rr_cols; c++) {
2310 raidz_col_t *rc = &rr->rr_col[c];
2311 if (rc->rc_error != 0) {
2312 ASSERT(n < VDEV_RAIDZ_MAXPARITY);
2313 tgts[n++] = c;
2314 }
2315 }
2316
2317 ASSERT(rr->rr_firstdatacol >= n);
2318
2319 vdev_raidz_reconstruct_row(rm, rr, tgts, n);
2320 }
2321 }
2322
2323 /*
2324 * Return the number of reads issued.
2325 */
2326 static int
2327 vdev_raidz_read_all(zio_t *zio, raidz_row_t *rr)
2328 {
2329 vdev_t *vd = zio->io_vd;
2330 int nread = 0;
2331
2332 rr->rr_missingdata = 0;
2333 rr->rr_missingparity = 0;
2334
2335 /*
2336 * If this rows contains empty sectors which are not required
2337 * for a normal read then allocate an ABD for them now so they
2338 * may be read, verified, and any needed repairs performed.
2339 */
2340 if (rr->rr_nempty && rr->rr_abd_empty == NULL)
2341 vdev_draid_map_alloc_empty(zio, rr);
2342
2343 for (int c = 0; c < rr->rr_cols; c++) {
2344 raidz_col_t *rc = &rr->rr_col[c];
2345 if (rc->rc_tried || rc->rc_size == 0)
2346 continue;
2347
2348 zio_nowait(zio_vdev_child_io(zio, NULL,
2349 vd->vdev_child[rc->rc_devidx],
2350 rc->rc_offset, rc->rc_abd, rc->rc_size,
2351 zio->io_type, zio->io_priority, 0,
2352 vdev_raidz_child_done, rc));
2353 nread++;
2354 }
2355 return (nread);
2356 }
2357
2358 /*
2359 * We're here because either there were too many errors to even attempt
2360 * reconstruction (total_errors == rm_first_datacol), or vdev_*_combrec()
2361 * failed. In either case, there is enough bad data to prevent reconstruction.
2362 * Start checksum ereports for all children which haven't failed.
2363 */
2364 static void
2365 vdev_raidz_io_done_unrecoverable(zio_t *zio)
2366 {
2367 raidz_map_t *rm = zio->io_vsd;
2368
2369 for (int i = 0; i < rm->rm_nrows; i++) {
2370 raidz_row_t *rr = rm->rm_row[i];
2371
2372 for (int c = 0; c < rr->rr_cols; c++) {
2373 raidz_col_t *rc = &rr->rr_col[c];
2374 vdev_t *cvd = zio->io_vd->vdev_child[rc->rc_devidx];
2375
2376 if (rc->rc_error != 0)
2377 continue;
2378
2379 zio_bad_cksum_t zbc;
2380 zbc.zbc_has_cksum = 0;
2381 zbc.zbc_injected = rm->rm_ecksuminjected;
2382
2383 mutex_enter(&cvd->vdev_stat_lock);
2384 cvd->vdev_stat.vs_checksum_errors++;
2385 mutex_exit(&cvd->vdev_stat_lock);
2386 (void) zfs_ereport_start_checksum(zio->io_spa,
2387 cvd, &zio->io_bookmark, zio, rc->rc_offset,
2388 rc->rc_size, &zbc);
2389 }
2390 }
2391 }
2392
2393 void
2394 vdev_raidz_io_done(zio_t *zio)
2395 {
2396 raidz_map_t *rm = zio->io_vsd;
2397
2398 if (zio->io_type == ZIO_TYPE_WRITE) {
2399 for (int i = 0; i < rm->rm_nrows; i++) {
2400 vdev_raidz_io_done_write_impl(zio, rm->rm_row[i]);
2401 }
2402 } else {
2403 for (int i = 0; i < rm->rm_nrows; i++) {
2404 raidz_row_t *rr = rm->rm_row[i];
2405 vdev_raidz_io_done_reconstruct_known_missing(zio,
2406 rm, rr);
2407 }
2408
2409 if (raidz_checksum_verify(zio) == 0) {
2410 for (int i = 0; i < rm->rm_nrows; i++) {
2411 raidz_row_t *rr = rm->rm_row[i];
2412 vdev_raidz_io_done_verified(zio, rr);
2413 }
2414 zio_checksum_verified(zio);
2415 } else {
2416 /*
2417 * A sequential resilver has no checksum which makes
2418 * combinatoral reconstruction impossible. This code
2419 * path is unreachable since raidz_checksum_verify()
2420 * has no checksum to verify and must succeed.
2421 */
2422 ASSERT3U(zio->io_priority, !=, ZIO_PRIORITY_REBUILD);
2423
2424 /*
2425 * This isn't a typical situation -- either we got a
2426 * read error or a child silently returned bad data.
2427 * Read every block so we can try again with as much
2428 * data and parity as we can track down. If we've
2429 * already been through once before, all children will
2430 * be marked as tried so we'll proceed to combinatorial
2431 * reconstruction.
2432 */
2433 int nread = 0;
2434 for (int i = 0; i < rm->rm_nrows; i++) {
2435 nread += vdev_raidz_read_all(zio,
2436 rm->rm_row[i]);
2437 }
2438 if (nread != 0) {
2439 /*
2440 * Normally our stage is VDEV_IO_DONE, but if
2441 * we've already called redone(), it will have
2442 * changed to VDEV_IO_START, in which case we
2443 * don't want to call redone() again.
2444 */
2445 if (zio->io_stage != ZIO_STAGE_VDEV_IO_START)
2446 zio_vdev_io_redone(zio);
2447 return;
2448 }
2449
2450 zio->io_error = vdev_raidz_combrec(zio);
2451 if (zio->io_error == ECKSUM &&
2452 !(zio->io_flags & ZIO_FLAG_SPECULATIVE)) {
2453 vdev_raidz_io_done_unrecoverable(zio);
2454 }
2455 }
2456 }
2457 }
2458
2459 static void
2460 vdev_raidz_state_change(vdev_t *vd, int faulted, int degraded)
2461 {
2462 vdev_raidz_t *vdrz = vd->vdev_tsd;
2463 if (faulted > vdrz->vd_nparity)
2464 vdev_set_state(vd, B_FALSE, VDEV_STATE_CANT_OPEN,
2465 VDEV_AUX_NO_REPLICAS);
2466 else if (degraded + faulted != 0)
2467 vdev_set_state(vd, B_FALSE, VDEV_STATE_DEGRADED, VDEV_AUX_NONE);
2468 else
2469 vdev_set_state(vd, B_FALSE, VDEV_STATE_HEALTHY, VDEV_AUX_NONE);
2470 }
2471
2472 /*
2473 * Determine if any portion of the provided block resides on a child vdev
2474 * with a dirty DTL and therefore needs to be resilvered. The function
2475 * assumes that at least one DTL is dirty which implies that full stripe
2476 * width blocks must be resilvered.
2477 */
2478 static boolean_t
2479 vdev_raidz_need_resilver(vdev_t *vd, const dva_t *dva, size_t psize,
2480 uint64_t phys_birth)
2481 {
2482 vdev_raidz_t *vdrz = vd->vdev_tsd;
2483 uint64_t dcols = vd->vdev_children;
2484 uint64_t nparity = vdrz->vd_nparity;
2485 uint64_t ashift = vd->vdev_top->vdev_ashift;
2486 /* The starting RAIDZ (parent) vdev sector of the block. */
2487 uint64_t b = DVA_GET_OFFSET(dva) >> ashift;
2488 /* The zio's size in units of the vdev's minimum sector size. */
2489 uint64_t s = ((psize - 1) >> ashift) + 1;
2490 /* The first column for this stripe. */
2491 uint64_t f = b % dcols;
2492
2493 /* Unreachable by sequential resilver. */
2494 ASSERT3U(phys_birth, !=, TXG_UNKNOWN);
2495
2496 if (!vdev_dtl_contains(vd, DTL_PARTIAL, phys_birth, 1))
2497 return (B_FALSE);
2498
2499 if (s + nparity >= dcols)
2500 return (B_TRUE);
2501
2502 for (uint64_t c = 0; c < s + nparity; c++) {
2503 uint64_t devidx = (f + c) % dcols;
2504 vdev_t *cvd = vd->vdev_child[devidx];
2505
2506 /*
2507 * dsl_scan_need_resilver() already checked vd with
2508 * vdev_dtl_contains(). So here just check cvd with
2509 * vdev_dtl_empty(), cheaper and a good approximation.
2510 */
2511 if (!vdev_dtl_empty(cvd, DTL_PARTIAL))
2512 return (B_TRUE);
2513 }
2514
2515 return (B_FALSE);
2516 }
2517
2518 static void
2519 vdev_raidz_xlate(vdev_t *cvd, const range_seg64_t *logical_rs,
2520 range_seg64_t *physical_rs, range_seg64_t *remain_rs)
2521 {
2522 (void) remain_rs;
2523
2524 vdev_t *raidvd = cvd->vdev_parent;
2525 ASSERT(raidvd->vdev_ops == &vdev_raidz_ops);
2526
2527 uint64_t width = raidvd->vdev_children;
2528 uint64_t tgt_col = cvd->vdev_id;
2529 uint64_t ashift = raidvd->vdev_top->vdev_ashift;
2530
2531 /* make sure the offsets are block-aligned */
2532 ASSERT0(logical_rs->rs_start % (1 << ashift));
2533 ASSERT0(logical_rs->rs_end % (1 << ashift));
2534 uint64_t b_start = logical_rs->rs_start >> ashift;
2535 uint64_t b_end = logical_rs->rs_end >> ashift;
2536
2537 uint64_t start_row = 0;
2538 if (b_start > tgt_col) /* avoid underflow */
2539 start_row = ((b_start - tgt_col - 1) / width) + 1;
2540
2541 uint64_t end_row = 0;
2542 if (b_end > tgt_col)
2543 end_row = ((b_end - tgt_col - 1) / width) + 1;
2544
2545 physical_rs->rs_start = start_row << ashift;
2546 physical_rs->rs_end = end_row << ashift;
2547
2548 ASSERT3U(physical_rs->rs_start, <=, logical_rs->rs_start);
2549 ASSERT3U(physical_rs->rs_end - physical_rs->rs_start, <=,
2550 logical_rs->rs_end - logical_rs->rs_start);
2551 }
2552
2553 /*
2554 * Initialize private RAIDZ specific fields from the nvlist.
2555 */
2556 static int
2557 vdev_raidz_init(spa_t *spa, nvlist_t *nv, void **tsd)
2558 {
2559 vdev_raidz_t *vdrz;
2560 uint64_t nparity;
2561
2562 uint_t children;
2563 nvlist_t **child;
2564 int error = nvlist_lookup_nvlist_array(nv,
2565 ZPOOL_CONFIG_CHILDREN, &child, &children);
2566 if (error != 0)
2567 return (SET_ERROR(EINVAL));
2568
2569 if (nvlist_lookup_uint64(nv, ZPOOL_CONFIG_NPARITY, &nparity) == 0) {
2570 if (nparity == 0 || nparity > VDEV_RAIDZ_MAXPARITY)
2571 return (SET_ERROR(EINVAL));
2572
2573 /*
2574 * Previous versions could only support 1 or 2 parity
2575 * device.
2576 */
2577 if (nparity > 1 && spa_version(spa) < SPA_VERSION_RAIDZ2)
2578 return (SET_ERROR(EINVAL));
2579 else if (nparity > 2 && spa_version(spa) < SPA_VERSION_RAIDZ3)
2580 return (SET_ERROR(EINVAL));
2581 } else {
2582 /*
2583 * We require the parity to be specified for SPAs that
2584 * support multiple parity levels.
2585 */
2586 if (spa_version(spa) >= SPA_VERSION_RAIDZ2)
2587 return (SET_ERROR(EINVAL));
2588
2589 /*
2590 * Otherwise, we default to 1 parity device for RAID-Z.
2591 */
2592 nparity = 1;
2593 }
2594
2595 vdrz = kmem_zalloc(sizeof (*vdrz), KM_SLEEP);
2596 vdrz->vd_logical_width = children;
2597 vdrz->vd_nparity = nparity;
2598
2599 *tsd = vdrz;
2600
2601 return (0);
2602 }
2603
2604 static void
2605 vdev_raidz_fini(vdev_t *vd)
2606 {
2607 kmem_free(vd->vdev_tsd, sizeof (vdev_raidz_t));
2608 }
2609
2610 /*
2611 * Add RAIDZ specific fields to the config nvlist.
2612 */
2613 static void
2614 vdev_raidz_config_generate(vdev_t *vd, nvlist_t *nv)
2615 {
2616 ASSERT3P(vd->vdev_ops, ==, &vdev_raidz_ops);
2617 vdev_raidz_t *vdrz = vd->vdev_tsd;
2618
2619 /*
2620 * Make sure someone hasn't managed to sneak a fancy new vdev
2621 * into a crufty old storage pool.
2622 */
2623 ASSERT(vdrz->vd_nparity == 1 ||
2624 (vdrz->vd_nparity <= 2 &&
2625 spa_version(vd->vdev_spa) >= SPA_VERSION_RAIDZ2) ||
2626 (vdrz->vd_nparity <= 3 &&
2627 spa_version(vd->vdev_spa) >= SPA_VERSION_RAIDZ3));
2628
2629 /*
2630 * Note that we'll add these even on storage pools where they
2631 * aren't strictly required -- older software will just ignore
2632 * it.
2633 */
2634 fnvlist_add_uint64(nv, ZPOOL_CONFIG_NPARITY, vdrz->vd_nparity);
2635 }
2636
2637 static uint64_t
2638 vdev_raidz_nparity(vdev_t *vd)
2639 {
2640 vdev_raidz_t *vdrz = vd->vdev_tsd;
2641 return (vdrz->vd_nparity);
2642 }
2643
2644 static uint64_t
2645 vdev_raidz_ndisks(vdev_t *vd)
2646 {
2647 return (vd->vdev_children);
2648 }
2649
2650 vdev_ops_t vdev_raidz_ops = {
2651 .vdev_op_init = vdev_raidz_init,
2652 .vdev_op_fini = vdev_raidz_fini,
2653 .vdev_op_open = vdev_raidz_open,
2654 .vdev_op_close = vdev_raidz_close,
2655 .vdev_op_asize = vdev_raidz_asize,
2656 .vdev_op_min_asize = vdev_raidz_min_asize,
2657 .vdev_op_min_alloc = NULL,
2658 .vdev_op_io_start = vdev_raidz_io_start,
2659 .vdev_op_io_done = vdev_raidz_io_done,
2660 .vdev_op_state_change = vdev_raidz_state_change,
2661 .vdev_op_need_resilver = vdev_raidz_need_resilver,
2662 .vdev_op_hold = NULL,
2663 .vdev_op_rele = NULL,
2664 .vdev_op_remap = NULL,
2665 .vdev_op_xlate = vdev_raidz_xlate,
2666 .vdev_op_rebuild_asize = NULL,
2667 .vdev_op_metaslab_init = NULL,
2668 .vdev_op_config_generate = vdev_raidz_config_generate,
2669 .vdev_op_nparity = vdev_raidz_nparity,
2670 .vdev_op_ndisks = vdev_raidz_ndisks,
2671 .vdev_op_type = VDEV_TYPE_RAIDZ, /* name of this vdev type */
2672 .vdev_op_leaf = B_FALSE /* not a leaf vdev */
2673 };
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