4 * The contents of this file are subject to the terms of the
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15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
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23 * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
24 * Copyright (c) 2013 by Delphix. All rights reserved.
27 #include <sys/zfs_context.h>
29 #include <sys/vdev_impl.h>
31 #include <sys/zio_checksum.h>
32 #include <sys/fs/zfs.h>
33 #include <sys/fm/fs/zfs.h>
36 * Virtual device vector for RAID-Z.
38 * This vdev supports single, double, and triple parity. For single parity,
39 * we use a simple XOR of all the data columns. For double or triple parity,
40 * we use a special case of Reed-Solomon coding. This extends the
41 * technique described in "The mathematics of RAID-6" by H. Peter Anvin by
42 * drawing on the system described in "A Tutorial on Reed-Solomon Coding for
43 * Fault-Tolerance in RAID-like Systems" by James S. Plank on which the
44 * former is also based. The latter is designed to provide higher performance
47 * Note that the Plank paper claimed to support arbitrary N+M, but was then
48 * amended six years later identifying a critical flaw that invalidates its
49 * claims. Nevertheless, the technique can be adapted to work for up to
50 * triple parity. For additional parity, the amendment "Note: Correction to
51 * the 1997 Tutorial on Reed-Solomon Coding" by James S. Plank and Ying Ding
52 * is viable, but the additional complexity means that write performance will
55 * All of the methods above operate on a Galois field, defined over the
56 * integers mod 2^N. In our case we choose N=8 for GF(8) so that all elements
57 * can be expressed with a single byte. Briefly, the operations on the
58 * field are defined as follows:
60 * o addition (+) is represented by a bitwise XOR
61 * o subtraction (-) is therefore identical to addition: A + B = A - B
62 * o multiplication of A by 2 is defined by the following bitwise expression:
67 * (A * 2)_4 = A_3 + A_7
68 * (A * 2)_3 = A_2 + A_7
69 * (A * 2)_2 = A_1 + A_7
73 * In C, multiplying by 2 is therefore ((a << 1) ^ ((a & 0x80) ? 0x1d : 0)).
74 * As an aside, this multiplication is derived from the error correcting
75 * primitive polynomial x^8 + x^4 + x^3 + x^2 + 1.
77 * Observe that any number in the field (except for 0) can be expressed as a
78 * power of 2 -- a generator for the field. We store a table of the powers of
79 * 2 and logs base 2 for quick look ups, and exploit the fact that A * B can
80 * be rewritten as 2^(log_2(A) + log_2(B)) (where '+' is normal addition rather
81 * than field addition). The inverse of a field element A (A^-1) is therefore
82 * A ^ (255 - 1) = A^254.
84 * The up-to-three parity columns, P, Q, R over several data columns,
85 * D_0, ... D_n-1, can be expressed by field operations:
87 * P = D_0 + D_1 + ... + D_n-2 + D_n-1
88 * Q = 2^n-1 * D_0 + 2^n-2 * D_1 + ... + 2^1 * D_n-2 + 2^0 * D_n-1
89 * = ((...((D_0) * 2 + D_1) * 2 + ...) * 2 + D_n-2) * 2 + D_n-1
90 * R = 4^n-1 * D_0 + 4^n-2 * D_1 + ... + 4^1 * D_n-2 + 4^0 * D_n-1
91 * = ((...((D_0) * 4 + D_1) * 4 + ...) * 4 + D_n-2) * 4 + D_n-1
93 * We chose 1, 2, and 4 as our generators because 1 corresponds to the trival
94 * XOR operation, and 2 and 4 can be computed quickly and generate linearly-
95 * independent coefficients. (There are no additional coefficients that have
96 * this property which is why the uncorrected Plank method breaks down.)
98 * See the reconstruction code below for how P, Q and R can used individually
99 * or in concert to recover missing data columns.
102 typedef struct raidz_col {
103 uint64_t rc_devidx; /* child device index for I/O */
104 uint64_t rc_offset; /* device offset */
105 uint64_t rc_size; /* I/O size */
106 void *rc_data; /* I/O data */
107 void *rc_gdata; /* used to store the "good" version */
108 int rc_error; /* I/O error for this device */
109 uint8_t rc_tried; /* Did we attempt this I/O column? */
110 uint8_t rc_skipped; /* Did we skip this I/O column? */
113 typedef struct raidz_map {
114 uint64_t rm_cols; /* Regular column count */
115 uint64_t rm_scols; /* Count including skipped columns */
116 uint64_t rm_bigcols; /* Number of oversized columns */
117 uint64_t rm_asize; /* Actual total I/O size */
118 uint64_t rm_missingdata; /* Count of missing data devices */
119 uint64_t rm_missingparity; /* Count of missing parity devices */
120 uint64_t rm_firstdatacol; /* First data column/parity count */
121 uint64_t rm_nskip; /* Skipped sectors for padding */
122 uint64_t rm_skipstart; /* Column index of padding start */
123 void *rm_datacopy; /* rm_asize-buffer of copied data */
124 uintptr_t rm_reports; /* # of referencing checksum reports */
125 uint8_t rm_freed; /* map no longer has referencing ZIO */
126 uint8_t rm_ecksuminjected; /* checksum error was injected */
127 raidz_col_t rm_col[1]; /* Flexible array of I/O columns */
130 #define VDEV_RAIDZ_P 0
131 #define VDEV_RAIDZ_Q 1
132 #define VDEV_RAIDZ_R 2
134 #define VDEV_RAIDZ_MUL_2(x) (((x) << 1) ^ (((x) & 0x80) ? 0x1d : 0))
135 #define VDEV_RAIDZ_MUL_4(x) (VDEV_RAIDZ_MUL_2(VDEV_RAIDZ_MUL_2(x)))
138 * We provide a mechanism to perform the field multiplication operation on a
139 * 64-bit value all at once rather than a byte at a time. This works by
140 * creating a mask from the top bit in each byte and using that to
141 * conditionally apply the XOR of 0x1d.
143 #define VDEV_RAIDZ_64MUL_2(x, mask) \
145 (mask) = (x) & 0x8080808080808080ULL; \
146 (mask) = ((mask) << 1) - ((mask) >> 7); \
147 (x) = (((x) << 1) & 0xfefefefefefefefeULL) ^ \
148 ((mask) & 0x1d1d1d1d1d1d1d1d); \
151 #define VDEV_RAIDZ_64MUL_4(x, mask) \
153 VDEV_RAIDZ_64MUL_2((x), mask); \
154 VDEV_RAIDZ_64MUL_2((x), mask); \
158 * Force reconstruction to use the general purpose method.
160 int vdev_raidz_default_to_general;
162 /* Powers of 2 in the Galois field defined above. */
163 static const uint8_t vdev_raidz_pow2[256] = {
164 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80,
165 0x1d, 0x3a, 0x74, 0xe8, 0xcd, 0x87, 0x13, 0x26,
166 0x4c, 0x98, 0x2d, 0x5a, 0xb4, 0x75, 0xea, 0xc9,
167 0x8f, 0x03, 0x06, 0x0c, 0x18, 0x30, 0x60, 0xc0,
168 0x9d, 0x27, 0x4e, 0x9c, 0x25, 0x4a, 0x94, 0x35,
169 0x6a, 0xd4, 0xb5, 0x77, 0xee, 0xc1, 0x9f, 0x23,
170 0x46, 0x8c, 0x05, 0x0a, 0x14, 0x28, 0x50, 0xa0,
171 0x5d, 0xba, 0x69, 0xd2, 0xb9, 0x6f, 0xde, 0xa1,
172 0x5f, 0xbe, 0x61, 0xc2, 0x99, 0x2f, 0x5e, 0xbc,
173 0x65, 0xca, 0x89, 0x0f, 0x1e, 0x3c, 0x78, 0xf0,
174 0xfd, 0xe7, 0xd3, 0xbb, 0x6b, 0xd6, 0xb1, 0x7f,
175 0xfe, 0xe1, 0xdf, 0xa3, 0x5b, 0xb6, 0x71, 0xe2,
176 0xd9, 0xaf, 0x43, 0x86, 0x11, 0x22, 0x44, 0x88,
177 0x0d, 0x1a, 0x34, 0x68, 0xd0, 0xbd, 0x67, 0xce,
178 0x81, 0x1f, 0x3e, 0x7c, 0xf8, 0xed, 0xc7, 0x93,
179 0x3b, 0x76, 0xec, 0xc5, 0x97, 0x33, 0x66, 0xcc,
180 0x85, 0x17, 0x2e, 0x5c, 0xb8, 0x6d, 0xda, 0xa9,
181 0x4f, 0x9e, 0x21, 0x42, 0x84, 0x15, 0x2a, 0x54,
182 0xa8, 0x4d, 0x9a, 0x29, 0x52, 0xa4, 0x55, 0xaa,
183 0x49, 0x92, 0x39, 0x72, 0xe4, 0xd5, 0xb7, 0x73,
184 0xe6, 0xd1, 0xbf, 0x63, 0xc6, 0x91, 0x3f, 0x7e,
185 0xfc, 0xe5, 0xd7, 0xb3, 0x7b, 0xf6, 0xf1, 0xff,
186 0xe3, 0xdb, 0xab, 0x4b, 0x96, 0x31, 0x62, 0xc4,
187 0x95, 0x37, 0x6e, 0xdc, 0xa5, 0x57, 0xae, 0x41,
188 0x82, 0x19, 0x32, 0x64, 0xc8, 0x8d, 0x07, 0x0e,
189 0x1c, 0x38, 0x70, 0xe0, 0xdd, 0xa7, 0x53, 0xa6,
190 0x51, 0xa2, 0x59, 0xb2, 0x79, 0xf2, 0xf9, 0xef,
191 0xc3, 0x9b, 0x2b, 0x56, 0xac, 0x45, 0x8a, 0x09,
192 0x12, 0x24, 0x48, 0x90, 0x3d, 0x7a, 0xf4, 0xf5,
193 0xf7, 0xf3, 0xfb, 0xeb, 0xcb, 0x8b, 0x0b, 0x16,
194 0x2c, 0x58, 0xb0, 0x7d, 0xfa, 0xe9, 0xcf, 0x83,
195 0x1b, 0x36, 0x6c, 0xd8, 0xad, 0x47, 0x8e, 0x01
197 /* Logs of 2 in the Galois field defined above. */
198 static const uint8_t vdev_raidz_log2[256] = {
199 0x00, 0x00, 0x01, 0x19, 0x02, 0x32, 0x1a, 0xc6,
200 0x03, 0xdf, 0x33, 0xee, 0x1b, 0x68, 0xc7, 0x4b,
201 0x04, 0x64, 0xe0, 0x0e, 0x34, 0x8d, 0xef, 0x81,
202 0x1c, 0xc1, 0x69, 0xf8, 0xc8, 0x08, 0x4c, 0x71,
203 0x05, 0x8a, 0x65, 0x2f, 0xe1, 0x24, 0x0f, 0x21,
204 0x35, 0x93, 0x8e, 0xda, 0xf0, 0x12, 0x82, 0x45,
205 0x1d, 0xb5, 0xc2, 0x7d, 0x6a, 0x27, 0xf9, 0xb9,
206 0xc9, 0x9a, 0x09, 0x78, 0x4d, 0xe4, 0x72, 0xa6,
207 0x06, 0xbf, 0x8b, 0x62, 0x66, 0xdd, 0x30, 0xfd,
208 0xe2, 0x98, 0x25, 0xb3, 0x10, 0x91, 0x22, 0x88,
209 0x36, 0xd0, 0x94, 0xce, 0x8f, 0x96, 0xdb, 0xbd,
210 0xf1, 0xd2, 0x13, 0x5c, 0x83, 0x38, 0x46, 0x40,
211 0x1e, 0x42, 0xb6, 0xa3, 0xc3, 0x48, 0x7e, 0x6e,
212 0x6b, 0x3a, 0x28, 0x54, 0xfa, 0x85, 0xba, 0x3d,
213 0xca, 0x5e, 0x9b, 0x9f, 0x0a, 0x15, 0x79, 0x2b,
214 0x4e, 0xd4, 0xe5, 0xac, 0x73, 0xf3, 0xa7, 0x57,
215 0x07, 0x70, 0xc0, 0xf7, 0x8c, 0x80, 0x63, 0x0d,
216 0x67, 0x4a, 0xde, 0xed, 0x31, 0xc5, 0xfe, 0x18,
217 0xe3, 0xa5, 0x99, 0x77, 0x26, 0xb8, 0xb4, 0x7c,
218 0x11, 0x44, 0x92, 0xd9, 0x23, 0x20, 0x89, 0x2e,
219 0x37, 0x3f, 0xd1, 0x5b, 0x95, 0xbc, 0xcf, 0xcd,
220 0x90, 0x87, 0x97, 0xb2, 0xdc, 0xfc, 0xbe, 0x61,
221 0xf2, 0x56, 0xd3, 0xab, 0x14, 0x2a, 0x5d, 0x9e,
222 0x84, 0x3c, 0x39, 0x53, 0x47, 0x6d, 0x41, 0xa2,
223 0x1f, 0x2d, 0x43, 0xd8, 0xb7, 0x7b, 0xa4, 0x76,
224 0xc4, 0x17, 0x49, 0xec, 0x7f, 0x0c, 0x6f, 0xf6,
225 0x6c, 0xa1, 0x3b, 0x52, 0x29, 0x9d, 0x55, 0xaa,
226 0xfb, 0x60, 0x86, 0xb1, 0xbb, 0xcc, 0x3e, 0x5a,
227 0xcb, 0x59, 0x5f, 0xb0, 0x9c, 0xa9, 0xa0, 0x51,
228 0x0b, 0xf5, 0x16, 0xeb, 0x7a, 0x75, 0x2c, 0xd7,
229 0x4f, 0xae, 0xd5, 0xe9, 0xe6, 0xe7, 0xad, 0xe8,
230 0x74, 0xd6, 0xf4, 0xea, 0xa8, 0x50, 0x58, 0xaf,
233 static void vdev_raidz_generate_parity(raidz_map_t *rm);
236 * Multiply a given number by 2 raised to the given power.
239 vdev_raidz_exp2(uint_t a, int exp)
245 ASSERT(vdev_raidz_log2[a] > 0 || a == 1);
247 exp += vdev_raidz_log2[a];
251 return (vdev_raidz_pow2[exp]);
255 vdev_raidz_map_free(raidz_map_t *rm)
260 for (c = 0; c < rm->rm_firstdatacol; c++) {
261 if (rm->rm_col[c].rc_data != NULL)
262 zio_buf_free(rm->rm_col[c].rc_data,
263 rm->rm_col[c].rc_size);
265 if (rm->rm_col[c].rc_gdata != NULL)
266 zio_buf_free(rm->rm_col[c].rc_gdata,
267 rm->rm_col[c].rc_size);
271 for (c = rm->rm_firstdatacol; c < rm->rm_cols; c++)
272 size += rm->rm_col[c].rc_size;
274 if (rm->rm_datacopy != NULL)
275 zio_buf_free(rm->rm_datacopy, size);
277 kmem_free(rm, offsetof(raidz_map_t, rm_col[rm->rm_scols]));
281 vdev_raidz_map_free_vsd(zio_t *zio)
283 raidz_map_t *rm = zio->io_vsd;
285 ASSERT0(rm->rm_freed);
288 if (rm->rm_reports == 0)
289 vdev_raidz_map_free(rm);
294 vdev_raidz_cksum_free(void *arg, size_t ignored)
296 raidz_map_t *rm = arg;
298 ASSERT3U(rm->rm_reports, >, 0);
300 if (--rm->rm_reports == 0 && rm->rm_freed != 0)
301 vdev_raidz_map_free(rm);
305 vdev_raidz_cksum_finish(zio_cksum_report_t *zcr, const void *good_data)
307 raidz_map_t *rm = zcr->zcr_cbdata;
308 size_t c = zcr->zcr_cbinfo;
311 const char *good = NULL;
312 const char *bad = rm->rm_col[c].rc_data;
314 if (good_data == NULL) {
315 zfs_ereport_finish_checksum(zcr, NULL, NULL, B_FALSE);
319 if (c < rm->rm_firstdatacol) {
321 * The first time through, calculate the parity blocks for
322 * the good data (this relies on the fact that the good
323 * data never changes for a given logical ZIO)
325 if (rm->rm_col[0].rc_gdata == NULL) {
326 char *bad_parity[VDEV_RAIDZ_MAXPARITY];
330 * Set up the rm_col[]s to generate the parity for
331 * good_data, first saving the parity bufs and
332 * replacing them with buffers to hold the result.
334 for (x = 0; x < rm->rm_firstdatacol; x++) {
335 bad_parity[x] = rm->rm_col[x].rc_data;
336 rm->rm_col[x].rc_data = rm->rm_col[x].rc_gdata =
337 zio_buf_alloc(rm->rm_col[x].rc_size);
340 /* fill in the data columns from good_data */
341 buf = (char *)good_data;
342 for (; x < rm->rm_cols; x++) {
343 rm->rm_col[x].rc_data = buf;
344 buf += rm->rm_col[x].rc_size;
348 * Construct the parity from the good data.
350 vdev_raidz_generate_parity(rm);
352 /* restore everything back to its original state */
353 for (x = 0; x < rm->rm_firstdatacol; x++)
354 rm->rm_col[x].rc_data = bad_parity[x];
356 buf = rm->rm_datacopy;
357 for (x = rm->rm_firstdatacol; x < rm->rm_cols; x++) {
358 rm->rm_col[x].rc_data = buf;
359 buf += rm->rm_col[x].rc_size;
363 ASSERT3P(rm->rm_col[c].rc_gdata, !=, NULL);
364 good = rm->rm_col[c].rc_gdata;
366 /* adjust good_data to point at the start of our column */
369 for (x = rm->rm_firstdatacol; x < c; x++)
370 good += rm->rm_col[x].rc_size;
373 /* we drop the ereport if it ends up that the data was good */
374 zfs_ereport_finish_checksum(zcr, good, bad, B_TRUE);
378 * Invoked indirectly by zfs_ereport_start_checksum(), called
379 * below when our read operation fails completely. The main point
380 * is to keep a copy of everything we read from disk, so that at
381 * vdev_raidz_cksum_finish() time we can compare it with the good data.
384 vdev_raidz_cksum_report(zio_t *zio, zio_cksum_report_t *zcr, void *arg)
386 size_t c = (size_t)(uintptr_t)arg;
389 raidz_map_t *rm = zio->io_vsd;
392 /* set up the report and bump the refcount */
393 zcr->zcr_cbdata = rm;
395 zcr->zcr_finish = vdev_raidz_cksum_finish;
396 zcr->zcr_free = vdev_raidz_cksum_free;
399 ASSERT3U(rm->rm_reports, >, 0);
401 if (rm->rm_datacopy != NULL)
405 * It's the first time we're called for this raidz_map_t, so we need
406 * to copy the data aside; there's no guarantee that our zio's buffer
407 * won't be re-used for something else.
409 * Our parity data is already in separate buffers, so there's no need
414 for (c = rm->rm_firstdatacol; c < rm->rm_cols; c++)
415 size += rm->rm_col[c].rc_size;
417 buf = rm->rm_datacopy = zio_buf_alloc(size);
419 for (c = rm->rm_firstdatacol; c < rm->rm_cols; c++) {
420 raidz_col_t *col = &rm->rm_col[c];
422 bcopy(col->rc_data, buf, col->rc_size);
427 ASSERT3P(buf - (caddr_t)rm->rm_datacopy, ==, size);
430 static const zio_vsd_ops_t vdev_raidz_vsd_ops = {
431 vdev_raidz_map_free_vsd,
432 vdev_raidz_cksum_report
436 * Divides the IO evenly across all child vdevs; usually, dcols is
437 * the number of children in the target vdev.
440 vdev_raidz_map_alloc(zio_t *zio, uint64_t unit_shift, uint64_t dcols,
444 /* The starting RAIDZ (parent) vdev sector of the block. */
445 uint64_t b = zio->io_offset >> unit_shift;
446 /* The zio's size in units of the vdev's minimum sector size. */
447 uint64_t s = zio->io_size >> unit_shift;
448 /* The first column for this stripe. */
449 uint64_t f = b % dcols;
450 /* The starting byte offset on each child vdev. */
451 uint64_t o = (b / dcols) << unit_shift;
452 uint64_t q, r, c, bc, col, acols, scols, coff, devidx, asize, tot;
455 * "Quotient": The number of data sectors for this stripe on all but
456 * the "big column" child vdevs that also contain "remainder" data.
458 q = s / (dcols - nparity);
461 * "Remainder": The number of partial stripe data sectors in this I/O.
462 * This will add a sector to some, but not all, child vdevs.
464 r = s - q * (dcols - nparity);
466 /* The number of "big columns" - those which contain remainder data. */
467 bc = (r == 0 ? 0 : r + nparity);
470 * The total number of data and parity sectors associated with
473 tot = s + nparity * (q + (r == 0 ? 0 : 1));
475 /* acols: The columns that will be accessed. */
476 /* scols: The columns that will be accessed or skipped. */
478 /* Our I/O request doesn't span all child vdevs. */
480 scols = MIN(dcols, roundup(bc, nparity + 1));
486 ASSERT3U(acols, <=, scols);
488 rm = kmem_alloc(offsetof(raidz_map_t, rm_col[scols]), KM_SLEEP);
491 rm->rm_scols = scols;
493 rm->rm_skipstart = bc;
494 rm->rm_missingdata = 0;
495 rm->rm_missingparity = 0;
496 rm->rm_firstdatacol = nparity;
497 rm->rm_datacopy = NULL;
500 rm->rm_ecksuminjected = 0;
504 for (c = 0; c < scols; c++) {
509 coff += 1ULL << unit_shift;
511 rm->rm_col[c].rc_devidx = col;
512 rm->rm_col[c].rc_offset = coff;
513 rm->rm_col[c].rc_data = NULL;
514 rm->rm_col[c].rc_gdata = NULL;
515 rm->rm_col[c].rc_error = 0;
516 rm->rm_col[c].rc_tried = 0;
517 rm->rm_col[c].rc_skipped = 0;
520 rm->rm_col[c].rc_size = 0;
522 rm->rm_col[c].rc_size = (q + 1) << unit_shift;
524 rm->rm_col[c].rc_size = q << unit_shift;
526 asize += rm->rm_col[c].rc_size;
529 ASSERT3U(asize, ==, tot << unit_shift);
530 rm->rm_asize = roundup(asize, (nparity + 1) << unit_shift);
531 rm->rm_nskip = roundup(tot, nparity + 1) - tot;
532 ASSERT3U(rm->rm_asize - asize, ==, rm->rm_nskip << unit_shift);
533 ASSERT3U(rm->rm_nskip, <=, nparity);
535 if (zio->io_type != ZIO_TYPE_FREE) {
536 for (c = 0; c < rm->rm_firstdatacol; c++) {
537 rm->rm_col[c].rc_data =
538 zio_buf_alloc(rm->rm_col[c].rc_size);
541 rm->rm_col[c].rc_data = zio->io_data;
543 for (c = c + 1; c < acols; c++) {
544 rm->rm_col[c].rc_data =
545 (char *)rm->rm_col[c - 1].rc_data +
546 rm->rm_col[c - 1].rc_size;
551 * If all data stored spans all columns, there's a danger that parity
552 * will always be on the same device and, since parity isn't read
553 * during normal operation, that that device's I/O bandwidth won't be
554 * used effectively. We therefore switch the parity every 1MB.
556 * ... at least that was, ostensibly, the theory. As a practical
557 * matter unless we juggle the parity between all devices evenly, we
558 * won't see any benefit. Further, occasional writes that aren't a
559 * multiple of the LCM of the number of children and the minimum
560 * stripe width are sufficient to avoid pessimal behavior.
561 * Unfortunately, this decision created an implicit on-disk format
562 * requirement that we need to support for all eternity, but only
563 * for single-parity RAID-Z.
565 * If we intend to skip a sector in the zeroth column for padding
566 * we must make sure to note this swap. We will never intend to
567 * skip the first column since at least one data and one parity
568 * column must appear in each row.
570 ASSERT(rm->rm_cols >= 2);
571 ASSERT(rm->rm_col[0].rc_size == rm->rm_col[1].rc_size);
573 if (rm->rm_firstdatacol == 1 && (zio->io_offset & (1ULL << 20))) {
574 devidx = rm->rm_col[0].rc_devidx;
575 o = rm->rm_col[0].rc_offset;
576 rm->rm_col[0].rc_devidx = rm->rm_col[1].rc_devidx;
577 rm->rm_col[0].rc_offset = rm->rm_col[1].rc_offset;
578 rm->rm_col[1].rc_devidx = devidx;
579 rm->rm_col[1].rc_offset = o;
581 if (rm->rm_skipstart == 0)
582 rm->rm_skipstart = 1;
586 zio->io_vsd_ops = &vdev_raidz_vsd_ops;
591 vdev_raidz_generate_parity_p(raidz_map_t *rm)
593 uint64_t *p, *src, pcount, ccount, i;
596 pcount = rm->rm_col[VDEV_RAIDZ_P].rc_size / sizeof (src[0]);
598 for (c = rm->rm_firstdatacol; c < rm->rm_cols; c++) {
599 src = rm->rm_col[c].rc_data;
600 p = rm->rm_col[VDEV_RAIDZ_P].rc_data;
601 ccount = rm->rm_col[c].rc_size / sizeof (src[0]);
603 if (c == rm->rm_firstdatacol) {
604 ASSERT(ccount == pcount);
605 for (i = 0; i < ccount; i++, src++, p++) {
609 ASSERT(ccount <= pcount);
610 for (i = 0; i < ccount; i++, src++, p++) {
618 vdev_raidz_generate_parity_pq(raidz_map_t *rm)
620 uint64_t *p, *q, *src, pcnt, ccnt, mask, i;
623 pcnt = rm->rm_col[VDEV_RAIDZ_P].rc_size / sizeof (src[0]);
624 ASSERT(rm->rm_col[VDEV_RAIDZ_P].rc_size ==
625 rm->rm_col[VDEV_RAIDZ_Q].rc_size);
627 for (c = rm->rm_firstdatacol; c < rm->rm_cols; c++) {
628 src = rm->rm_col[c].rc_data;
629 p = rm->rm_col[VDEV_RAIDZ_P].rc_data;
630 q = rm->rm_col[VDEV_RAIDZ_Q].rc_data;
632 ccnt = rm->rm_col[c].rc_size / sizeof (src[0]);
634 if (c == rm->rm_firstdatacol) {
635 ASSERT(ccnt == pcnt || ccnt == 0);
636 for (i = 0; i < ccnt; i++, src++, p++, q++) {
640 for (; i < pcnt; i++, src++, p++, q++) {
645 ASSERT(ccnt <= pcnt);
648 * Apply the algorithm described above by multiplying
649 * the previous result and adding in the new value.
651 for (i = 0; i < ccnt; i++, src++, p++, q++) {
654 VDEV_RAIDZ_64MUL_2(*q, mask);
659 * Treat short columns as though they are full of 0s.
660 * Note that there's therefore nothing needed for P.
662 for (; i < pcnt; i++, q++) {
663 VDEV_RAIDZ_64MUL_2(*q, mask);
670 vdev_raidz_generate_parity_pqr(raidz_map_t *rm)
672 uint64_t *p, *q, *r, *src, pcnt, ccnt, mask, i;
675 pcnt = rm->rm_col[VDEV_RAIDZ_P].rc_size / sizeof (src[0]);
676 ASSERT(rm->rm_col[VDEV_RAIDZ_P].rc_size ==
677 rm->rm_col[VDEV_RAIDZ_Q].rc_size);
678 ASSERT(rm->rm_col[VDEV_RAIDZ_P].rc_size ==
679 rm->rm_col[VDEV_RAIDZ_R].rc_size);
681 for (c = rm->rm_firstdatacol; c < rm->rm_cols; c++) {
682 src = rm->rm_col[c].rc_data;
683 p = rm->rm_col[VDEV_RAIDZ_P].rc_data;
684 q = rm->rm_col[VDEV_RAIDZ_Q].rc_data;
685 r = rm->rm_col[VDEV_RAIDZ_R].rc_data;
687 ccnt = rm->rm_col[c].rc_size / sizeof (src[0]);
689 if (c == rm->rm_firstdatacol) {
690 ASSERT(ccnt == pcnt || ccnt == 0);
691 for (i = 0; i < ccnt; i++, src++, p++, q++, r++) {
696 for (; i < pcnt; i++, src++, p++, q++, r++) {
702 ASSERT(ccnt <= pcnt);
705 * Apply the algorithm described above by multiplying
706 * the previous result and adding in the new value.
708 for (i = 0; i < ccnt; i++, src++, p++, q++, r++) {
711 VDEV_RAIDZ_64MUL_2(*q, mask);
714 VDEV_RAIDZ_64MUL_4(*r, mask);
719 * Treat short columns as though they are full of 0s.
720 * Note that there's therefore nothing needed for P.
722 for (; i < pcnt; i++, q++, r++) {
723 VDEV_RAIDZ_64MUL_2(*q, mask);
724 VDEV_RAIDZ_64MUL_4(*r, mask);
731 * Generate RAID parity in the first virtual columns according to the number of
732 * parity columns available.
735 vdev_raidz_generate_parity(raidz_map_t *rm)
737 switch (rm->rm_firstdatacol) {
739 vdev_raidz_generate_parity_p(rm);
742 vdev_raidz_generate_parity_pq(rm);
745 vdev_raidz_generate_parity_pqr(rm);
748 cmn_err(CE_PANIC, "invalid RAID-Z configuration");
753 vdev_raidz_reconstruct_p(raidz_map_t *rm, int *tgts, int ntgts)
755 uint64_t *dst, *src, xcount, ccount, count, i;
760 ASSERT(x >= rm->rm_firstdatacol);
761 ASSERT(x < rm->rm_cols);
763 xcount = rm->rm_col[x].rc_size / sizeof (src[0]);
764 ASSERT(xcount <= rm->rm_col[VDEV_RAIDZ_P].rc_size / sizeof (src[0]));
767 src = rm->rm_col[VDEV_RAIDZ_P].rc_data;
768 dst = rm->rm_col[x].rc_data;
769 for (i = 0; i < xcount; i++, dst++, src++) {
773 for (c = rm->rm_firstdatacol; c < rm->rm_cols; c++) {
774 src = rm->rm_col[c].rc_data;
775 dst = rm->rm_col[x].rc_data;
780 ccount = rm->rm_col[c].rc_size / sizeof (src[0]);
781 count = MIN(ccount, xcount);
783 for (i = 0; i < count; i++, dst++, src++) {
788 return (1 << VDEV_RAIDZ_P);
792 vdev_raidz_reconstruct_q(raidz_map_t *rm, int *tgts, int ntgts)
794 uint64_t *dst, *src, xcount, ccount, count, mask, i;
801 xcount = rm->rm_col[x].rc_size / sizeof (src[0]);
802 ASSERT(xcount <= rm->rm_col[VDEV_RAIDZ_Q].rc_size / sizeof (src[0]));
804 for (c = rm->rm_firstdatacol; c < rm->rm_cols; c++) {
805 src = rm->rm_col[c].rc_data;
806 dst = rm->rm_col[x].rc_data;
811 ccount = rm->rm_col[c].rc_size / sizeof (src[0]);
813 count = MIN(ccount, xcount);
815 if (c == rm->rm_firstdatacol) {
816 for (i = 0; i < count; i++, dst++, src++) {
819 for (; i < xcount; i++, dst++) {
824 for (i = 0; i < count; i++, dst++, src++) {
825 VDEV_RAIDZ_64MUL_2(*dst, mask);
829 for (; i < xcount; i++, dst++) {
830 VDEV_RAIDZ_64MUL_2(*dst, mask);
835 src = rm->rm_col[VDEV_RAIDZ_Q].rc_data;
836 dst = rm->rm_col[x].rc_data;
837 exp = 255 - (rm->rm_cols - 1 - x);
839 for (i = 0; i < xcount; i++, dst++, src++) {
841 for (j = 0, b = (uint8_t *)dst; j < 8; j++, b++) {
842 *b = vdev_raidz_exp2(*b, exp);
846 return (1 << VDEV_RAIDZ_Q);
850 vdev_raidz_reconstruct_pq(raidz_map_t *rm, int *tgts, int ntgts)
852 uint8_t *p, *q, *pxy, *qxy, *xd, *yd, tmp, a, b, aexp, bexp;
854 uint64_t xsize, ysize, i;
860 ASSERT(x >= rm->rm_firstdatacol);
861 ASSERT(y < rm->rm_cols);
863 ASSERT(rm->rm_col[x].rc_size >= rm->rm_col[y].rc_size);
866 * Move the parity data aside -- we're going to compute parity as
867 * though columns x and y were full of zeros -- Pxy and Qxy. We want to
868 * reuse the parity generation mechanism without trashing the actual
869 * parity so we make those columns appear to be full of zeros by
870 * setting their lengths to zero.
872 pdata = rm->rm_col[VDEV_RAIDZ_P].rc_data;
873 qdata = rm->rm_col[VDEV_RAIDZ_Q].rc_data;
874 xsize = rm->rm_col[x].rc_size;
875 ysize = rm->rm_col[y].rc_size;
877 rm->rm_col[VDEV_RAIDZ_P].rc_data =
878 zio_buf_alloc(rm->rm_col[VDEV_RAIDZ_P].rc_size);
879 rm->rm_col[VDEV_RAIDZ_Q].rc_data =
880 zio_buf_alloc(rm->rm_col[VDEV_RAIDZ_Q].rc_size);
881 rm->rm_col[x].rc_size = 0;
882 rm->rm_col[y].rc_size = 0;
884 vdev_raidz_generate_parity_pq(rm);
886 rm->rm_col[x].rc_size = xsize;
887 rm->rm_col[y].rc_size = ysize;
891 pxy = rm->rm_col[VDEV_RAIDZ_P].rc_data;
892 qxy = rm->rm_col[VDEV_RAIDZ_Q].rc_data;
893 xd = rm->rm_col[x].rc_data;
894 yd = rm->rm_col[y].rc_data;
898 * Pxy = P + D_x + D_y
899 * Qxy = Q + 2^(ndevs - 1 - x) * D_x + 2^(ndevs - 1 - y) * D_y
901 * We can then solve for D_x:
902 * D_x = A * (P + Pxy) + B * (Q + Qxy)
904 * A = 2^(x - y) * (2^(x - y) + 1)^-1
905 * B = 2^(ndevs - 1 - x) * (2^(x - y) + 1)^-1
907 * With D_x in hand, we can easily solve for D_y:
908 * D_y = P + Pxy + D_x
911 a = vdev_raidz_pow2[255 + x - y];
912 b = vdev_raidz_pow2[255 - (rm->rm_cols - 1 - x)];
913 tmp = 255 - vdev_raidz_log2[a ^ 1];
915 aexp = vdev_raidz_log2[vdev_raidz_exp2(a, tmp)];
916 bexp = vdev_raidz_log2[vdev_raidz_exp2(b, tmp)];
918 for (i = 0; i < xsize; i++, p++, q++, pxy++, qxy++, xd++, yd++) {
919 *xd = vdev_raidz_exp2(*p ^ *pxy, aexp) ^
920 vdev_raidz_exp2(*q ^ *qxy, bexp);
923 *yd = *p ^ *pxy ^ *xd;
926 zio_buf_free(rm->rm_col[VDEV_RAIDZ_P].rc_data,
927 rm->rm_col[VDEV_RAIDZ_P].rc_size);
928 zio_buf_free(rm->rm_col[VDEV_RAIDZ_Q].rc_data,
929 rm->rm_col[VDEV_RAIDZ_Q].rc_size);
932 * Restore the saved parity data.
934 rm->rm_col[VDEV_RAIDZ_P].rc_data = pdata;
935 rm->rm_col[VDEV_RAIDZ_Q].rc_data = qdata;
937 return ((1 << VDEV_RAIDZ_P) | (1 << VDEV_RAIDZ_Q));
942 * In the general case of reconstruction, we must solve the system of linear
943 * equations defined by the coeffecients used to generate parity as well as
944 * the contents of the data and parity disks. This can be expressed with
945 * vectors for the original data (D) and the actual data (d) and parity (p)
946 * and a matrix composed of the identity matrix (I) and a dispersal matrix (V):
950 * | V | | D_0 | | p_m-1 |
951 * | | x | : | = | d_0 |
952 * | I | | D_n-1 | | : |
953 * | | ~~ ~~ | d_n-1 |
956 * I is simply a square identity matrix of size n, and V is a vandermonde
957 * matrix defined by the coeffecients we chose for the various parity columns
958 * (1, 2, 4). Note that these values were chosen both for simplicity, speedy
959 * computation as well as linear separability.
962 * | 1 .. 1 1 1 | | p_0 |
963 * | 2^n-1 .. 4 2 1 | __ __ | : |
964 * | 4^n-1 .. 16 4 1 | | D_0 | | p_m-1 |
965 * | 1 .. 0 0 0 | | D_1 | | d_0 |
966 * | 0 .. 0 0 0 | x | D_2 | = | d_1 |
967 * | : : : : | | : | | d_2 |
968 * | 0 .. 1 0 0 | | D_n-1 | | : |
969 * | 0 .. 0 1 0 | ~~ ~~ | : |
970 * | 0 .. 0 0 1 | | d_n-1 |
973 * Note that I, V, d, and p are known. To compute D, we must invert the
974 * matrix and use the known data and parity values to reconstruct the unknown
975 * data values. We begin by removing the rows in V|I and d|p that correspond
976 * to failed or missing columns; we then make V|I square (n x n) and d|p
977 * sized n by removing rows corresponding to unused parity from the bottom up
978 * to generate (V|I)' and (d|p)'. We can then generate the inverse of (V|I)'
979 * using Gauss-Jordan elimination. In the example below we use m=3 parity
980 * columns, n=8 data columns, with errors in d_1, d_2, and p_1:
982 * | 1 1 1 1 1 1 1 1 |
983 * | 128 64 32 16 8 4 2 1 | <-----+-+-- missing disks
984 * | 19 205 116 29 64 16 4 1 | / /
985 * | 1 0 0 0 0 0 0 0 | / /
986 * | 0 1 0 0 0 0 0 0 | <--' /
987 * (V|I) = | 0 0 1 0 0 0 0 0 | <---'
988 * | 0 0 0 1 0 0 0 0 |
989 * | 0 0 0 0 1 0 0 0 |
990 * | 0 0 0 0 0 1 0 0 |
991 * | 0 0 0 0 0 0 1 0 |
992 * | 0 0 0 0 0 0 0 1 |
995 * | 1 1 1 1 1 1 1 1 |
996 * | 128 64 32 16 8 4 2 1 |
997 * | 19 205 116 29 64 16 4 1 |
998 * | 1 0 0 0 0 0 0 0 |
999 * | 0 1 0 0 0 0 0 0 |
1000 * (V|I)' = | 0 0 1 0 0 0 0 0 |
1001 * | 0 0 0 1 0 0 0 0 |
1002 * | 0 0 0 0 1 0 0 0 |
1003 * | 0 0 0 0 0 1 0 0 |
1004 * | 0 0 0 0 0 0 1 0 |
1005 * | 0 0 0 0 0 0 0 1 |
1008 * Here we employ Gauss-Jordan elimination to find the inverse of (V|I)'. We
1009 * have carefully chosen the seed values 1, 2, and 4 to ensure that this
1010 * matrix is not singular.
1012 * | 1 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 |
1013 * | 19 205 116 29 64 16 4 1 0 1 0 0 0 0 0 0 |
1014 * | 1 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 |
1015 * | 0 0 0 1 0 0 0 0 0 0 0 1 0 0 0 0 |
1016 * | 0 0 0 0 1 0 0 0 0 0 0 0 1 0 0 0 |
1017 * | 0 0 0 0 0 1 0 0 0 0 0 0 0 1 0 0 |
1018 * | 0 0 0 0 0 0 1 0 0 0 0 0 0 0 1 0 |
1019 * | 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 1 |
1022 * | 1 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 |
1023 * | 1 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 |
1024 * | 19 205 116 29 64 16 4 1 0 1 0 0 0 0 0 0 |
1025 * | 0 0 0 1 0 0 0 0 0 0 0 1 0 0 0 0 |
1026 * | 0 0 0 0 1 0 0 0 0 0 0 0 1 0 0 0 |
1027 * | 0 0 0 0 0 1 0 0 0 0 0 0 0 1 0 0 |
1028 * | 0 0 0 0 0 0 1 0 0 0 0 0 0 0 1 0 |
1029 * | 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 1 |
1032 * | 1 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 |
1033 * | 0 1 1 0 0 0 0 0 1 0 1 1 1 1 1 1 |
1034 * | 0 205 116 0 0 0 0 0 0 1 19 29 64 16 4 1 |
1035 * | 0 0 0 1 0 0 0 0 0 0 0 1 0 0 0 0 |
1036 * | 0 0 0 0 1 0 0 0 0 0 0 0 1 0 0 0 |
1037 * | 0 0 0 0 0 1 0 0 0 0 0 0 0 1 0 0 |
1038 * | 0 0 0 0 0 0 1 0 0 0 0 0 0 0 1 0 |
1039 * | 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 1 |
1042 * | 1 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 |
1043 * | 0 1 1 0 0 0 0 0 1 0 1 1 1 1 1 1 |
1044 * | 0 0 185 0 0 0 0 0 205 1 222 208 141 221 201 204 |
1045 * | 0 0 0 1 0 0 0 0 0 0 0 1 0 0 0 0 |
1046 * | 0 0 0 0 1 0 0 0 0 0 0 0 1 0 0 0 |
1047 * | 0 0 0 0 0 1 0 0 0 0 0 0 0 1 0 0 |
1048 * | 0 0 0 0 0 0 1 0 0 0 0 0 0 0 1 0 |
1049 * | 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 1 |
1052 * | 1 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 |
1053 * | 0 1 1 0 0 0 0 0 1 0 1 1 1 1 1 1 |
1054 * | 0 0 1 0 0 0 0 0 166 100 4 40 158 168 216 209 |
1055 * | 0 0 0 1 0 0 0 0 0 0 0 1 0 0 0 0 |
1056 * | 0 0 0 0 1 0 0 0 0 0 0 0 1 0 0 0 |
1057 * | 0 0 0 0 0 1 0 0 0 0 0 0 0 1 0 0 |
1058 * | 0 0 0 0 0 0 1 0 0 0 0 0 0 0 1 0 |
1059 * | 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 1 |
1062 * | 1 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 |
1063 * | 0 1 0 0 0 0 0 0 167 100 5 41 159 169 217 208 |
1064 * | 0 0 1 0 0 0 0 0 166 100 4 40 158 168 216 209 |
1065 * | 0 0 0 1 0 0 0 0 0 0 0 1 0 0 0 0 |
1066 * | 0 0 0 0 1 0 0 0 0 0 0 0 1 0 0 0 |
1067 * | 0 0 0 0 0 1 0 0 0 0 0 0 0 1 0 0 |
1068 * | 0 0 0 0 0 0 1 0 0 0 0 0 0 0 1 0 |
1069 * | 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 1 |
1072 * | 0 0 1 0 0 0 0 0 |
1073 * | 167 100 5 41 159 169 217 208 |
1074 * | 166 100 4 40 158 168 216 209 |
1075 * (V|I)'^-1 = | 0 0 0 1 0 0 0 0 |
1076 * | 0 0 0 0 1 0 0 0 |
1077 * | 0 0 0 0 0 1 0 0 |
1078 * | 0 0 0 0 0 0 1 0 |
1079 * | 0 0 0 0 0 0 0 1 |
1082 * We can then simply compute D = (V|I)'^-1 x (d|p)' to discover the values
1083 * of the missing data.
1085 * As is apparent from the example above, the only non-trivial rows in the
1086 * inverse matrix correspond to the data disks that we're trying to
1087 * reconstruct. Indeed, those are the only rows we need as the others would
1088 * only be useful for reconstructing data known or assumed to be valid. For
1089 * that reason, we only build the coefficients in the rows that correspond to
1095 vdev_raidz_matrix_init(raidz_map_t *rm, int n, int nmap, int *map,
1101 ASSERT(n == rm->rm_cols - rm->rm_firstdatacol);
1104 * Fill in the missing rows of interest.
1106 for (i = 0; i < nmap; i++) {
1107 ASSERT3S(0, <=, map[i]);
1108 ASSERT3S(map[i], <=, 2);
1115 for (j = 0; j < n; j++) {
1119 rows[i][j] = vdev_raidz_pow2[pow];
1125 vdev_raidz_matrix_invert(raidz_map_t *rm, int n, int nmissing, int *missing,
1126 uint8_t **rows, uint8_t **invrows, const uint8_t *used)
1132 * Assert that the first nmissing entries from the array of used
1133 * columns correspond to parity columns and that subsequent entries
1134 * correspond to data columns.
1136 for (i = 0; i < nmissing; i++) {
1137 ASSERT3S(used[i], <, rm->rm_firstdatacol);
1139 for (; i < n; i++) {
1140 ASSERT3S(used[i], >=, rm->rm_firstdatacol);
1144 * First initialize the storage where we'll compute the inverse rows.
1146 for (i = 0; i < nmissing; i++) {
1147 for (j = 0; j < n; j++) {
1148 invrows[i][j] = (i == j) ? 1 : 0;
1153 * Subtract all trivial rows from the rows of consequence.
1155 for (i = 0; i < nmissing; i++) {
1156 for (j = nmissing; j < n; j++) {
1157 ASSERT3U(used[j], >=, rm->rm_firstdatacol);
1158 jj = used[j] - rm->rm_firstdatacol;
1160 invrows[i][j] = rows[i][jj];
1166 * For each of the rows of interest, we must normalize it and subtract
1167 * a multiple of it from the other rows.
1169 for (i = 0; i < nmissing; i++) {
1170 for (j = 0; j < missing[i]; j++) {
1171 ASSERT0(rows[i][j]);
1173 ASSERT3U(rows[i][missing[i]], !=, 0);
1176 * Compute the inverse of the first element and multiply each
1177 * element in the row by that value.
1179 log = 255 - vdev_raidz_log2[rows[i][missing[i]]];
1181 for (j = 0; j < n; j++) {
1182 rows[i][j] = vdev_raidz_exp2(rows[i][j], log);
1183 invrows[i][j] = vdev_raidz_exp2(invrows[i][j], log);
1186 for (ii = 0; ii < nmissing; ii++) {
1190 ASSERT3U(rows[ii][missing[i]], !=, 0);
1192 log = vdev_raidz_log2[rows[ii][missing[i]]];
1194 for (j = 0; j < n; j++) {
1196 vdev_raidz_exp2(rows[i][j], log);
1198 vdev_raidz_exp2(invrows[i][j], log);
1204 * Verify that the data that is left in the rows are properly part of
1205 * an identity matrix.
1207 for (i = 0; i < nmissing; i++) {
1208 for (j = 0; j < n; j++) {
1209 if (j == missing[i]) {
1210 ASSERT3U(rows[i][j], ==, 1);
1212 ASSERT0(rows[i][j]);
1219 vdev_raidz_matrix_reconstruct(raidz_map_t *rm, int n, int nmissing,
1220 int *missing, uint8_t **invrows, const uint8_t *used)
1225 uint8_t *dst[VDEV_RAIDZ_MAXPARITY];
1226 uint64_t dcount[VDEV_RAIDZ_MAXPARITY];
1230 uint8_t *invlog[VDEV_RAIDZ_MAXPARITY];
1234 psize = sizeof (invlog[0][0]) * n * nmissing;
1235 p = kmem_alloc(psize, KM_SLEEP);
1237 for (pp = p, i = 0; i < nmissing; i++) {
1242 for (i = 0; i < nmissing; i++) {
1243 for (j = 0; j < n; j++) {
1244 ASSERT3U(invrows[i][j], !=, 0);
1245 invlog[i][j] = vdev_raidz_log2[invrows[i][j]];
1249 for (i = 0; i < n; i++) {
1251 ASSERT3U(c, <, rm->rm_cols);
1253 src = rm->rm_col[c].rc_data;
1254 ccount = rm->rm_col[c].rc_size;
1255 for (j = 0; j < nmissing; j++) {
1256 cc = missing[j] + rm->rm_firstdatacol;
1257 ASSERT3U(cc, >=, rm->rm_firstdatacol);
1258 ASSERT3U(cc, <, rm->rm_cols);
1259 ASSERT3U(cc, !=, c);
1261 dst[j] = rm->rm_col[cc].rc_data;
1262 dcount[j] = rm->rm_col[cc].rc_size;
1265 ASSERT(ccount >= rm->rm_col[missing[0]].rc_size || i > 0);
1267 for (x = 0; x < ccount; x++, src++) {
1269 log = vdev_raidz_log2[*src];
1271 for (cc = 0; cc < nmissing; cc++) {
1272 if (x >= dcount[cc])
1278 if ((ll = log + invlog[cc][i]) >= 255)
1280 val = vdev_raidz_pow2[ll];
1291 kmem_free(p, psize);
1295 vdev_raidz_reconstruct_general(raidz_map_t *rm, int *tgts, int ntgts)
1299 int missing_rows[VDEV_RAIDZ_MAXPARITY];
1300 int parity_map[VDEV_RAIDZ_MAXPARITY];
1305 uint8_t *rows[VDEV_RAIDZ_MAXPARITY];
1306 uint8_t *invrows[VDEV_RAIDZ_MAXPARITY];
1312 n = rm->rm_cols - rm->rm_firstdatacol;
1315 * Figure out which data columns are missing.
1318 for (t = 0; t < ntgts; t++) {
1319 if (tgts[t] >= rm->rm_firstdatacol) {
1320 missing_rows[nmissing_rows++] =
1321 tgts[t] - rm->rm_firstdatacol;
1326 * Figure out which parity columns to use to help generate the missing
1329 for (tt = 0, c = 0, i = 0; i < nmissing_rows; c++) {
1331 ASSERT(c < rm->rm_firstdatacol);
1334 * Skip any targeted parity columns.
1336 if (c == tgts[tt]) {
1348 ASSERT3U(code, <, 1 << VDEV_RAIDZ_MAXPARITY);
1350 psize = (sizeof (rows[0][0]) + sizeof (invrows[0][0])) *
1351 nmissing_rows * n + sizeof (used[0]) * n;
1352 p = kmem_alloc(psize, KM_SLEEP);
1354 for (pp = p, i = 0; i < nmissing_rows; i++) {
1362 for (i = 0; i < nmissing_rows; i++) {
1363 used[i] = parity_map[i];
1366 for (tt = 0, c = rm->rm_firstdatacol; c < rm->rm_cols; c++) {
1367 if (tt < nmissing_rows &&
1368 c == missing_rows[tt] + rm->rm_firstdatacol) {
1379 * Initialize the interesting rows of the matrix.
1381 vdev_raidz_matrix_init(rm, n, nmissing_rows, parity_map, rows);
1384 * Invert the matrix.
1386 vdev_raidz_matrix_invert(rm, n, nmissing_rows, missing_rows, rows,
1390 * Reconstruct the missing data using the generated matrix.
1392 vdev_raidz_matrix_reconstruct(rm, n, nmissing_rows, missing_rows,
1395 kmem_free(p, psize);
1401 vdev_raidz_reconstruct(raidz_map_t *rm, int *t, int nt)
1403 int tgts[VDEV_RAIDZ_MAXPARITY], *dt;
1407 int nbadparity, nbaddata;
1408 int parity_valid[VDEV_RAIDZ_MAXPARITY];
1411 * The tgts list must already be sorted.
1413 for (i = 1; i < nt; i++) {
1414 ASSERT(t[i] > t[i - 1]);
1417 nbadparity = rm->rm_firstdatacol;
1418 nbaddata = rm->rm_cols - nbadparity;
1420 for (i = 0, c = 0; c < rm->rm_cols; c++) {
1421 if (c < rm->rm_firstdatacol)
1422 parity_valid[c] = B_FALSE;
1424 if (i < nt && c == t[i]) {
1427 } else if (rm->rm_col[c].rc_error != 0) {
1429 } else if (c >= rm->rm_firstdatacol) {
1432 parity_valid[c] = B_TRUE;
1437 ASSERT(ntgts >= nt);
1438 ASSERT(nbaddata >= 0);
1439 ASSERT(nbaddata + nbadparity == ntgts);
1441 dt = &tgts[nbadparity];
1444 * See if we can use any of our optimized reconstruction routines.
1446 if (!vdev_raidz_default_to_general) {
1449 if (parity_valid[VDEV_RAIDZ_P])
1450 return (vdev_raidz_reconstruct_p(rm, dt, 1));
1452 ASSERT(rm->rm_firstdatacol > 1);
1454 if (parity_valid[VDEV_RAIDZ_Q])
1455 return (vdev_raidz_reconstruct_q(rm, dt, 1));
1457 ASSERT(rm->rm_firstdatacol > 2);
1461 ASSERT(rm->rm_firstdatacol > 1);
1463 if (parity_valid[VDEV_RAIDZ_P] &&
1464 parity_valid[VDEV_RAIDZ_Q])
1465 return (vdev_raidz_reconstruct_pq(rm, dt, 2));
1467 ASSERT(rm->rm_firstdatacol > 2);
1473 code = vdev_raidz_reconstruct_general(rm, tgts, ntgts);
1474 ASSERT(code < (1 << VDEV_RAIDZ_MAXPARITY));
1480 vdev_raidz_open(vdev_t *vd, uint64_t *asize, uint64_t *max_asize,
1484 uint64_t nparity = vd->vdev_nparity;
1489 ASSERT(nparity > 0);
1491 if (nparity > VDEV_RAIDZ_MAXPARITY ||
1492 vd->vdev_children < nparity + 1) {
1493 vd->vdev_stat.vs_aux = VDEV_AUX_BAD_LABEL;
1494 return (SET_ERROR(EINVAL));
1497 vdev_open_children(vd);
1499 for (c = 0; c < vd->vdev_children; c++) {
1500 cvd = vd->vdev_child[c];
1502 if (cvd->vdev_open_error != 0) {
1503 lasterror = cvd->vdev_open_error;
1508 *asize = MIN(*asize - 1, cvd->vdev_asize - 1) + 1;
1509 *max_asize = MIN(*max_asize - 1, cvd->vdev_max_asize - 1) + 1;
1510 *ashift = MAX(*ashift, cvd->vdev_ashift);
1513 *asize *= vd->vdev_children;
1514 *max_asize *= vd->vdev_children;
1516 if (numerrors > nparity) {
1517 vd->vdev_stat.vs_aux = VDEV_AUX_NO_REPLICAS;
1525 vdev_raidz_close(vdev_t *vd)
1529 for (c = 0; c < vd->vdev_children; c++)
1530 vdev_close(vd->vdev_child[c]);
1534 vdev_raidz_asize(vdev_t *vd, uint64_t psize)
1537 uint64_t ashift = vd->vdev_top->vdev_ashift;
1538 uint64_t cols = vd->vdev_children;
1539 uint64_t nparity = vd->vdev_nparity;
1541 asize = ((psize - 1) >> ashift) + 1;
1542 asize += nparity * ((asize + cols - nparity - 1) / (cols - nparity));
1543 asize = roundup(asize, nparity + 1) << ashift;
1549 vdev_raidz_child_done(zio_t *zio)
1551 raidz_col_t *rc = zio->io_private;
1553 rc->rc_error = zio->io_error;
1559 * Start an IO operation on a RAIDZ VDev
1562 * - For write operations:
1563 * 1. Generate the parity data
1564 * 2. Create child zio write operations to each column's vdev, for both
1566 * 3. If the column skips any sectors for padding, create optional dummy
1567 * write zio children for those areas to improve aggregation continuity.
1568 * - For read operations:
1569 * 1. Create child zio read operations to each data column's vdev to read
1570 * the range of data required for zio.
1571 * 2. If this is a scrub or resilver operation, or if any of the data
1572 * vdevs have had errors, then create zio read operations to the parity
1573 * columns' VDevs as well.
1576 vdev_raidz_io_start(zio_t *zio)
1578 vdev_t *vd = zio->io_vd;
1579 vdev_t *tvd = vd->vdev_top;
1585 rm = vdev_raidz_map_alloc(zio, tvd->vdev_ashift, vd->vdev_children,
1588 ASSERT3U(rm->rm_asize, ==, vdev_psize_to_asize(vd, zio->io_size));
1590 if (zio->io_type == ZIO_TYPE_FREE) {
1591 for (c = 0; c < rm->rm_cols; c++) {
1592 rc = &rm->rm_col[c];
1593 cvd = vd->vdev_child[rc->rc_devidx];
1594 zio_nowait(zio_vdev_child_io(zio, NULL, cvd,
1595 rc->rc_offset, rc->rc_data, rc->rc_size,
1596 zio->io_type, zio->io_priority, 0,
1597 vdev_raidz_child_done, rc));
1599 return (ZIO_PIPELINE_CONTINUE);
1602 if (zio->io_type == ZIO_TYPE_WRITE) {
1603 vdev_raidz_generate_parity(rm);
1605 for (c = 0; c < rm->rm_cols; c++) {
1606 rc = &rm->rm_col[c];
1607 cvd = vd->vdev_child[rc->rc_devidx];
1608 zio_nowait(zio_vdev_child_io(zio, NULL, cvd,
1609 rc->rc_offset, rc->rc_data, rc->rc_size,
1610 zio->io_type, zio->io_priority, 0,
1611 vdev_raidz_child_done, rc));
1615 * Generate optional I/Os for any skipped sectors to improve
1616 * aggregation contiguity.
1618 for (c = rm->rm_skipstart, i = 0; i < rm->rm_nskip; c++, i++) {
1619 ASSERT(c <= rm->rm_scols);
1620 if (c == rm->rm_scols)
1622 rc = &rm->rm_col[c];
1623 cvd = vd->vdev_child[rc->rc_devidx];
1624 zio_nowait(zio_vdev_child_io(zio, NULL, cvd,
1625 rc->rc_offset + rc->rc_size, NULL,
1626 1 << tvd->vdev_ashift,
1627 zio->io_type, zio->io_priority,
1628 ZIO_FLAG_NODATA | ZIO_FLAG_OPTIONAL, NULL, NULL));
1631 return (ZIO_PIPELINE_CONTINUE);
1634 ASSERT(zio->io_type == ZIO_TYPE_READ);
1637 * Iterate over the columns in reverse order so that we hit the parity
1638 * last -- any errors along the way will force us to read the parity.
1640 for (c = rm->rm_cols - 1; c >= 0; c--) {
1641 rc = &rm->rm_col[c];
1642 cvd = vd->vdev_child[rc->rc_devidx];
1643 if (!vdev_readable(cvd)) {
1644 if (c >= rm->rm_firstdatacol)
1645 rm->rm_missingdata++;
1647 rm->rm_missingparity++;
1648 rc->rc_error = SET_ERROR(ENXIO);
1649 rc->rc_tried = 1; /* don't even try */
1653 if (vdev_dtl_contains(cvd, DTL_MISSING, zio->io_txg, 1)) {
1654 if (c >= rm->rm_firstdatacol)
1655 rm->rm_missingdata++;
1657 rm->rm_missingparity++;
1658 rc->rc_error = SET_ERROR(ESTALE);
1662 if (c >= rm->rm_firstdatacol || rm->rm_missingdata > 0 ||
1663 (zio->io_flags & (ZIO_FLAG_SCRUB | ZIO_FLAG_RESILVER))) {
1664 zio_nowait(zio_vdev_child_io(zio, NULL, cvd,
1665 rc->rc_offset, rc->rc_data, rc->rc_size,
1666 zio->io_type, zio->io_priority, 0,
1667 vdev_raidz_child_done, rc));
1671 return (ZIO_PIPELINE_CONTINUE);
1676 * Report a checksum error for a child of a RAID-Z device.
1679 raidz_checksum_error(zio_t *zio, raidz_col_t *rc, void *bad_data)
1681 vdev_t *vd = zio->io_vd->vdev_child[rc->rc_devidx];
1683 if (!(zio->io_flags & ZIO_FLAG_SPECULATIVE)) {
1684 zio_bad_cksum_t zbc;
1685 raidz_map_t *rm = zio->io_vsd;
1687 mutex_enter(&vd->vdev_stat_lock);
1688 vd->vdev_stat.vs_checksum_errors++;
1689 mutex_exit(&vd->vdev_stat_lock);
1691 zbc.zbc_has_cksum = 0;
1692 zbc.zbc_injected = rm->rm_ecksuminjected;
1694 zfs_ereport_post_checksum(zio->io_spa, vd, zio,
1695 rc->rc_offset, rc->rc_size, rc->rc_data, bad_data,
1701 * We keep track of whether or not there were any injected errors, so that
1702 * any ereports we generate can note it.
1705 raidz_checksum_verify(zio_t *zio)
1707 zio_bad_cksum_t zbc;
1708 raidz_map_t *rm = zio->io_vsd;
1710 int ret = zio_checksum_error(zio, &zbc);
1711 if (ret != 0 && zbc.zbc_injected != 0)
1712 rm->rm_ecksuminjected = 1;
1718 * Generate the parity from the data columns. If we tried and were able to
1719 * read the parity without error, verify that the generated parity matches the
1720 * data we read. If it doesn't, we fire off a checksum error. Return the
1721 * number such failures.
1724 raidz_parity_verify(zio_t *zio, raidz_map_t *rm)
1726 void *orig[VDEV_RAIDZ_MAXPARITY];
1730 for (c = 0; c < rm->rm_firstdatacol; c++) {
1731 rc = &rm->rm_col[c];
1732 if (!rc->rc_tried || rc->rc_error != 0)
1734 orig[c] = zio_buf_alloc(rc->rc_size);
1735 bcopy(rc->rc_data, orig[c], rc->rc_size);
1738 vdev_raidz_generate_parity(rm);
1740 for (c = 0; c < rm->rm_firstdatacol; c++) {
1741 rc = &rm->rm_col[c];
1742 if (!rc->rc_tried || rc->rc_error != 0)
1744 if (bcmp(orig[c], rc->rc_data, rc->rc_size) != 0) {
1745 raidz_checksum_error(zio, rc, orig[c]);
1746 rc->rc_error = SET_ERROR(ECKSUM);
1749 zio_buf_free(orig[c], rc->rc_size);
1756 * Keep statistics on all the ways that we used parity to correct data.
1758 static uint64_t raidz_corrected[1 << VDEV_RAIDZ_MAXPARITY];
1761 vdev_raidz_worst_error(raidz_map_t *rm)
1765 for (int c = 0; c < rm->rm_cols; c++)
1766 error = zio_worst_error(error, rm->rm_col[c].rc_error);
1772 * Iterate over all combinations of bad data and attempt a reconstruction.
1773 * Note that the algorithm below is non-optimal because it doesn't take into
1774 * account how reconstruction is actually performed. For example, with
1775 * triple-parity RAID-Z the reconstruction procedure is the same if column 4
1776 * is targeted as invalid as if columns 1 and 4 are targeted since in both
1777 * cases we'd only use parity information in column 0.
1780 vdev_raidz_combrec(zio_t *zio, int total_errors, int data_errors)
1782 raidz_map_t *rm = zio->io_vsd;
1784 void *orig[VDEV_RAIDZ_MAXPARITY];
1785 int tstore[VDEV_RAIDZ_MAXPARITY + 2];
1786 int *tgts = &tstore[1];
1787 int current, next, i, c, n;
1790 ASSERT(total_errors < rm->rm_firstdatacol);
1793 * This simplifies one edge condition.
1797 for (n = 1; n <= rm->rm_firstdatacol - total_errors; n++) {
1799 * Initialize the targets array by finding the first n columns
1800 * that contain no error.
1802 * If there were no data errors, we need to ensure that we're
1803 * always explicitly attempting to reconstruct at least one
1804 * data column. To do this, we simply push the highest target
1805 * up into the data columns.
1807 for (c = 0, i = 0; i < n; i++) {
1808 if (i == n - 1 && data_errors == 0 &&
1809 c < rm->rm_firstdatacol) {
1810 c = rm->rm_firstdatacol;
1813 while (rm->rm_col[c].rc_error != 0) {
1815 ASSERT3S(c, <, rm->rm_cols);
1822 * Setting tgts[n] simplifies the other edge condition.
1824 tgts[n] = rm->rm_cols;
1827 * These buffers were allocated in previous iterations.
1829 for (i = 0; i < n - 1; i++) {
1830 ASSERT(orig[i] != NULL);
1833 orig[n - 1] = zio_buf_alloc(rm->rm_col[0].rc_size);
1836 next = tgts[current];
1838 while (current != n) {
1839 tgts[current] = next;
1843 * Save off the original data that we're going to
1844 * attempt to reconstruct.
1846 for (i = 0; i < n; i++) {
1847 ASSERT(orig[i] != NULL);
1850 ASSERT3S(c, <, rm->rm_cols);
1851 rc = &rm->rm_col[c];
1852 bcopy(rc->rc_data, orig[i], rc->rc_size);
1856 * Attempt a reconstruction and exit the outer loop on
1859 code = vdev_raidz_reconstruct(rm, tgts, n);
1860 if (raidz_checksum_verify(zio) == 0) {
1861 atomic_inc_64(&raidz_corrected[code]);
1863 for (i = 0; i < n; i++) {
1865 rc = &rm->rm_col[c];
1866 ASSERT(rc->rc_error == 0);
1868 raidz_checksum_error(zio, rc,
1870 rc->rc_error = SET_ERROR(ECKSUM);
1878 * Restore the original data.
1880 for (i = 0; i < n; i++) {
1882 rc = &rm->rm_col[c];
1883 bcopy(orig[i], rc->rc_data, rc->rc_size);
1888 * Find the next valid column after the current
1891 for (next = tgts[current] + 1;
1892 next < rm->rm_cols &&
1893 rm->rm_col[next].rc_error != 0; next++)
1896 ASSERT(next <= tgts[current + 1]);
1899 * If that spot is available, we're done here.
1901 if (next != tgts[current + 1])
1905 * Otherwise, find the next valid column after
1906 * the previous position.
1908 for (c = tgts[current - 1] + 1;
1909 rm->rm_col[c].rc_error != 0; c++)
1915 } while (current != n);
1920 for (i = 0; i < n; i++) {
1921 zio_buf_free(orig[i], rm->rm_col[0].rc_size);
1928 * Complete an IO operation on a RAIDZ VDev
1931 * - For write operations:
1932 * 1. Check for errors on the child IOs.
1933 * 2. Return, setting an error code if too few child VDevs were written
1934 * to reconstruct the data later. Note that partial writes are
1935 * considered successful if they can be reconstructed at all.
1936 * - For read operations:
1937 * 1. Check for errors on the child IOs.
1938 * 2. If data errors occurred:
1939 * a. Try to reassemble the data from the parity available.
1940 * b. If we haven't yet read the parity drives, read them now.
1941 * c. If all parity drives have been read but the data still doesn't
1942 * reassemble with a correct checksum, then try combinatorial
1944 * d. If that doesn't work, return an error.
1945 * 3. If there were unexpected errors or this is a resilver operation,
1946 * rewrite the vdevs that had errors.
1949 vdev_raidz_io_done(zio_t *zio)
1951 vdev_t *vd = zio->io_vd;
1953 raidz_map_t *rm = zio->io_vsd;
1955 int unexpected_errors = 0;
1956 int parity_errors = 0;
1957 int parity_untried = 0;
1958 int data_errors = 0;
1959 int total_errors = 0;
1961 int tgts[VDEV_RAIDZ_MAXPARITY];
1964 ASSERT(zio->io_bp != NULL); /* XXX need to add code to enforce this */
1966 ASSERT(rm->rm_missingparity <= rm->rm_firstdatacol);
1967 ASSERT(rm->rm_missingdata <= rm->rm_cols - rm->rm_firstdatacol);
1969 for (c = 0; c < rm->rm_cols; c++) {
1970 rc = &rm->rm_col[c];
1973 ASSERT(rc->rc_error != ECKSUM); /* child has no bp */
1975 if (c < rm->rm_firstdatacol)
1980 if (!rc->rc_skipped)
1981 unexpected_errors++;
1984 } else if (c < rm->rm_firstdatacol && !rc->rc_tried) {
1989 if (zio->io_type == ZIO_TYPE_WRITE) {
1991 * XXX -- for now, treat partial writes as a success.
1992 * (If we couldn't write enough columns to reconstruct
1993 * the data, the I/O failed. Otherwise, good enough.)
1995 * Now that we support write reallocation, it would be better
1996 * to treat partial failure as real failure unless there are
1997 * no non-degraded top-level vdevs left, and not update DTLs
1998 * if we intend to reallocate.
2001 if (total_errors > rm->rm_firstdatacol)
2002 zio->io_error = vdev_raidz_worst_error(rm);
2005 } else if (zio->io_type == ZIO_TYPE_FREE) {
2009 ASSERT(zio->io_type == ZIO_TYPE_READ);
2011 * There are three potential phases for a read:
2012 * 1. produce valid data from the columns read
2013 * 2. read all disks and try again
2014 * 3. perform combinatorial reconstruction
2016 * Each phase is progressively both more expensive and less likely to
2017 * occur. If we encounter more errors than we can repair or all phases
2018 * fail, we have no choice but to return an error.
2022 * If the number of errors we saw was correctable -- less than or equal
2023 * to the number of parity disks read -- attempt to produce data that
2024 * has a valid checksum. Naturally, this case applies in the absence of
2027 if (total_errors <= rm->rm_firstdatacol - parity_untried) {
2028 if (data_errors == 0) {
2029 if (raidz_checksum_verify(zio) == 0) {
2031 * If we read parity information (unnecessarily
2032 * as it happens since no reconstruction was
2033 * needed) regenerate and verify the parity.
2034 * We also regenerate parity when resilvering
2035 * so we can write it out to the failed device
2038 if (parity_errors + parity_untried <
2039 rm->rm_firstdatacol ||
2040 (zio->io_flags & ZIO_FLAG_RESILVER)) {
2041 n = raidz_parity_verify(zio, rm);
2042 unexpected_errors += n;
2043 ASSERT(parity_errors + n <=
2044 rm->rm_firstdatacol);
2050 * We either attempt to read all the parity columns or
2051 * none of them. If we didn't try to read parity, we
2052 * wouldn't be here in the correctable case. There must
2053 * also have been fewer parity errors than parity
2054 * columns or, again, we wouldn't be in this code path.
2056 ASSERT(parity_untried == 0);
2057 ASSERT(parity_errors < rm->rm_firstdatacol);
2060 * Identify the data columns that reported an error.
2063 for (c = rm->rm_firstdatacol; c < rm->rm_cols; c++) {
2064 rc = &rm->rm_col[c];
2065 if (rc->rc_error != 0) {
2066 ASSERT(n < VDEV_RAIDZ_MAXPARITY);
2071 ASSERT(rm->rm_firstdatacol >= n);
2073 code = vdev_raidz_reconstruct(rm, tgts, n);
2075 if (raidz_checksum_verify(zio) == 0) {
2076 atomic_inc_64(&raidz_corrected[code]);
2079 * If we read more parity disks than were used
2080 * for reconstruction, confirm that the other
2081 * parity disks produced correct data. This
2082 * routine is suboptimal in that it regenerates
2083 * the parity that we already used in addition
2084 * to the parity that we're attempting to
2085 * verify, but this should be a relatively
2086 * uncommon case, and can be optimized if it
2087 * becomes a problem. Note that we regenerate
2088 * parity when resilvering so we can write it
2089 * out to failed devices later.
2091 if (parity_errors < rm->rm_firstdatacol - n ||
2092 (zio->io_flags & ZIO_FLAG_RESILVER)) {
2093 n = raidz_parity_verify(zio, rm);
2094 unexpected_errors += n;
2095 ASSERT(parity_errors + n <=
2096 rm->rm_firstdatacol);
2105 * This isn't a typical situation -- either we got a read error or
2106 * a child silently returned bad data. Read every block so we can
2107 * try again with as much data and parity as we can track down. If
2108 * we've already been through once before, all children will be marked
2109 * as tried so we'll proceed to combinatorial reconstruction.
2111 unexpected_errors = 1;
2112 rm->rm_missingdata = 0;
2113 rm->rm_missingparity = 0;
2115 for (c = 0; c < rm->rm_cols; c++) {
2116 if (rm->rm_col[c].rc_tried)
2119 zio_vdev_io_redone(zio);
2121 rc = &rm->rm_col[c];
2124 zio_nowait(zio_vdev_child_io(zio, NULL,
2125 vd->vdev_child[rc->rc_devidx],
2126 rc->rc_offset, rc->rc_data, rc->rc_size,
2127 zio->io_type, zio->io_priority, 0,
2128 vdev_raidz_child_done, rc));
2129 } while (++c < rm->rm_cols);
2135 * At this point we've attempted to reconstruct the data given the
2136 * errors we detected, and we've attempted to read all columns. There
2137 * must, therefore, be one or more additional problems -- silent errors
2138 * resulting in invalid data rather than explicit I/O errors resulting
2139 * in absent data. We check if there is enough additional data to
2140 * possibly reconstruct the data and then perform combinatorial
2141 * reconstruction over all possible combinations. If that fails,
2144 if (total_errors > rm->rm_firstdatacol) {
2145 zio->io_error = vdev_raidz_worst_error(rm);
2147 } else if (total_errors < rm->rm_firstdatacol &&
2148 (code = vdev_raidz_combrec(zio, total_errors, data_errors)) != 0) {
2150 * If we didn't use all the available parity for the
2151 * combinatorial reconstruction, verify that the remaining
2152 * parity is correct.
2154 if (code != (1 << rm->rm_firstdatacol) - 1)
2155 (void) raidz_parity_verify(zio, rm);
2158 * We're here because either:
2160 * total_errors == rm_first_datacol, or
2161 * vdev_raidz_combrec() failed
2163 * In either case, there is enough bad data to prevent
2166 * Start checksum ereports for all children which haven't
2167 * failed, and the IO wasn't speculative.
2169 zio->io_error = SET_ERROR(ECKSUM);
2171 if (!(zio->io_flags & ZIO_FLAG_SPECULATIVE)) {
2172 for (c = 0; c < rm->rm_cols; c++) {
2173 rc = &rm->rm_col[c];
2174 if (rc->rc_error == 0) {
2175 zio_bad_cksum_t zbc;
2176 zbc.zbc_has_cksum = 0;
2178 rm->rm_ecksuminjected;
2180 zfs_ereport_start_checksum(
2182 vd->vdev_child[rc->rc_devidx],
2183 zio, rc->rc_offset, rc->rc_size,
2184 (void *)(uintptr_t)c, &zbc);
2191 zio_checksum_verified(zio);
2193 if (zio->io_error == 0 && spa_writeable(zio->io_spa) &&
2194 (unexpected_errors || (zio->io_flags & ZIO_FLAG_RESILVER))) {
2196 * Use the good data we have in hand to repair damaged children.
2198 for (c = 0; c < rm->rm_cols; c++) {
2199 rc = &rm->rm_col[c];
2200 cvd = vd->vdev_child[rc->rc_devidx];
2202 if (rc->rc_error == 0)
2205 zio_nowait(zio_vdev_child_io(zio, NULL, cvd,
2206 rc->rc_offset, rc->rc_data, rc->rc_size,
2207 ZIO_TYPE_WRITE, zio->io_priority,
2208 ZIO_FLAG_IO_REPAIR | (unexpected_errors ?
2209 ZIO_FLAG_SELF_HEAL : 0), NULL, NULL));
2215 vdev_raidz_state_change(vdev_t *vd, int faulted, int degraded)
2217 if (faulted > vd->vdev_nparity)
2218 vdev_set_state(vd, B_FALSE, VDEV_STATE_CANT_OPEN,
2219 VDEV_AUX_NO_REPLICAS);
2220 else if (degraded + faulted != 0)
2221 vdev_set_state(vd, B_FALSE, VDEV_STATE_DEGRADED, VDEV_AUX_NONE);
2223 vdev_set_state(vd, B_FALSE, VDEV_STATE_HEALTHY, VDEV_AUX_NONE);
2226 vdev_ops_t vdev_raidz_ops = {
2230 vdev_raidz_io_start,
2232 vdev_raidz_state_change,
2235 VDEV_TYPE_RAIDZ, /* name of this vdev type */
2236 B_FALSE /* not a leaf vdev */