]>
Commit | Line | Data |
---|---|---|
34dc7c2f BB |
1 | /* |
2 | * CDDL HEADER START | |
3 | * | |
4 | * The contents of this file are subject to the terms of the | |
5 | * Common Development and Distribution License (the "License"). | |
6 | * You may not use this file except in compliance with the License. | |
7 | * | |
8 | * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE | |
9 | * or http://www.opensolaris.org/os/licensing. | |
10 | * See the License for the specific language governing permissions | |
11 | * and limitations under the License. | |
12 | * | |
13 | * When distributing Covered Code, include this CDDL HEADER in each | |
14 | * file and include the License file at usr/src/OPENSOLARIS.LICENSE. | |
15 | * If applicable, add the following below this CDDL HEADER, with the | |
16 | * fields enclosed by brackets "[]" replaced with your own identifying | |
17 | * information: Portions Copyright [yyyy] [name of copyright owner] | |
18 | * | |
19 | * CDDL HEADER END | |
20 | */ | |
21 | ||
22 | /* | |
428870ff | 23 | * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved. |
34dc7c2f BB |
24 | */ |
25 | ||
34dc7c2f BB |
26 | #include <sys/zfs_context.h> |
27 | #include <sys/spa.h> | |
28 | #include <sys/vdev_impl.h> | |
29 | #include <sys/zio.h> | |
30 | #include <sys/zio_checksum.h> | |
31 | #include <sys/fs/zfs.h> | |
32 | #include <sys/fm/fs/zfs.h> | |
33 | ||
34 | /* | |
35 | * Virtual device vector for RAID-Z. | |
36 | * | |
45d1cae3 BB |
37 | * This vdev supports single, double, and triple parity. For single parity, |
38 | * we use a simple XOR of all the data columns. For double or triple parity, | |
39 | * we use a special case of Reed-Solomon coding. This extends the | |
40 | * technique described in "The mathematics of RAID-6" by H. Peter Anvin by | |
41 | * drawing on the system described in "A Tutorial on Reed-Solomon Coding for | |
42 | * Fault-Tolerance in RAID-like Systems" by James S. Plank on which the | |
43 | * former is also based. The latter is designed to provide higher performance | |
44 | * for writes. | |
45 | * | |
46 | * Note that the Plank paper claimed to support arbitrary N+M, but was then | |
47 | * amended six years later identifying a critical flaw that invalidates its | |
48 | * claims. Nevertheless, the technique can be adapted to work for up to | |
49 | * triple parity. For additional parity, the amendment "Note: Correction to | |
50 | * the 1997 Tutorial on Reed-Solomon Coding" by James S. Plank and Ying Ding | |
51 | * is viable, but the additional complexity means that write performance will | |
52 | * suffer. | |
53 | * | |
54 | * All of the methods above operate on a Galois field, defined over the | |
55 | * integers mod 2^N. In our case we choose N=8 for GF(8) so that all elements | |
56 | * can be expressed with a single byte. Briefly, the operations on the | |
57 | * field are defined as follows: | |
34dc7c2f BB |
58 | * |
59 | * o addition (+) is represented by a bitwise XOR | |
60 | * o subtraction (-) is therefore identical to addition: A + B = A - B | |
61 | * o multiplication of A by 2 is defined by the following bitwise expression: | |
62 | * (A * 2)_7 = A_6 | |
63 | * (A * 2)_6 = A_5 | |
64 | * (A * 2)_5 = A_4 | |
65 | * (A * 2)_4 = A_3 + A_7 | |
66 | * (A * 2)_3 = A_2 + A_7 | |
67 | * (A * 2)_2 = A_1 + A_7 | |
68 | * (A * 2)_1 = A_0 | |
69 | * (A * 2)_0 = A_7 | |
70 | * | |
71 | * In C, multiplying by 2 is therefore ((a << 1) ^ ((a & 0x80) ? 0x1d : 0)). | |
45d1cae3 BB |
72 | * As an aside, this multiplication is derived from the error correcting |
73 | * primitive polynomial x^8 + x^4 + x^3 + x^2 + 1. | |
34dc7c2f BB |
74 | * |
75 | * Observe that any number in the field (except for 0) can be expressed as a | |
76 | * power of 2 -- a generator for the field. We store a table of the powers of | |
77 | * 2 and logs base 2 for quick look ups, and exploit the fact that A * B can | |
78 | * be rewritten as 2^(log_2(A) + log_2(B)) (where '+' is normal addition rather | |
45d1cae3 BB |
79 | * than field addition). The inverse of a field element A (A^-1) is therefore |
80 | * A ^ (255 - 1) = A^254. | |
34dc7c2f | 81 | * |
45d1cae3 BB |
82 | * The up-to-three parity columns, P, Q, R over several data columns, |
83 | * D_0, ... D_n-1, can be expressed by field operations: | |
34dc7c2f BB |
84 | * |
85 | * P = D_0 + D_1 + ... + D_n-2 + D_n-1 | |
86 | * Q = 2^n-1 * D_0 + 2^n-2 * D_1 + ... + 2^1 * D_n-2 + 2^0 * D_n-1 | |
87 | * = ((...((D_0) * 2 + D_1) * 2 + ...) * 2 + D_n-2) * 2 + D_n-1 | |
45d1cae3 BB |
88 | * R = 4^n-1 * D_0 + 4^n-2 * D_1 + ... + 4^1 * D_n-2 + 4^0 * D_n-1 |
89 | * = ((...((D_0) * 4 + D_1) * 4 + ...) * 4 + D_n-2) * 4 + D_n-1 | |
34dc7c2f | 90 | * |
45d1cae3 BB |
91 | * We chose 1, 2, and 4 as our generators because 1 corresponds to the trival |
92 | * XOR operation, and 2 and 4 can be computed quickly and generate linearly- | |
93 | * independent coefficients. (There are no additional coefficients that have | |
94 | * this property which is why the uncorrected Plank method breaks down.) | |
95 | * | |
96 | * See the reconstruction code below for how P, Q and R can used individually | |
97 | * or in concert to recover missing data columns. | |
34dc7c2f BB |
98 | */ |
99 | ||
100 | typedef struct raidz_col { | |
101 | uint64_t rc_devidx; /* child device index for I/O */ | |
102 | uint64_t rc_offset; /* device offset */ | |
103 | uint64_t rc_size; /* I/O size */ | |
104 | void *rc_data; /* I/O data */ | |
428870ff | 105 | void *rc_gdata; /* used to store the "good" version */ |
34dc7c2f BB |
106 | int rc_error; /* I/O error for this device */ |
107 | uint8_t rc_tried; /* Did we attempt this I/O column? */ | |
108 | uint8_t rc_skipped; /* Did we skip this I/O column? */ | |
109 | } raidz_col_t; | |
110 | ||
111 | typedef struct raidz_map { | |
45d1cae3 BB |
112 | uint64_t rm_cols; /* Regular column count */ |
113 | uint64_t rm_scols; /* Count including skipped columns */ | |
34dc7c2f BB |
114 | uint64_t rm_bigcols; /* Number of oversized columns */ |
115 | uint64_t rm_asize; /* Actual total I/O size */ | |
116 | uint64_t rm_missingdata; /* Count of missing data devices */ | |
117 | uint64_t rm_missingparity; /* Count of missing parity devices */ | |
118 | uint64_t rm_firstdatacol; /* First data column/parity count */ | |
428870ff BB |
119 | uint64_t rm_nskip; /* Skipped sectors for padding */ |
120 | uint64_t rm_skipstart; /* Column index of padding start */ | |
121 | void *rm_datacopy; /* rm_asize-buffer of copied data */ | |
122 | uintptr_t rm_reports; /* # of referencing checksum reports */ | |
123 | uint8_t rm_freed; /* map no longer has referencing ZIO */ | |
124 | uint8_t rm_ecksuminjected; /* checksum error was injected */ | |
34dc7c2f BB |
125 | raidz_col_t rm_col[1]; /* Flexible array of I/O columns */ |
126 | } raidz_map_t; | |
127 | ||
128 | #define VDEV_RAIDZ_P 0 | |
129 | #define VDEV_RAIDZ_Q 1 | |
45d1cae3 | 130 | #define VDEV_RAIDZ_R 2 |
45d1cae3 BB |
131 | |
132 | #define VDEV_RAIDZ_MUL_2(x) (((x) << 1) ^ (((x) & 0x80) ? 0x1d : 0)) | |
133 | #define VDEV_RAIDZ_MUL_4(x) (VDEV_RAIDZ_MUL_2(VDEV_RAIDZ_MUL_2(x))) | |
134 | ||
135 | /* | |
136 | * We provide a mechanism to perform the field multiplication operation on a | |
137 | * 64-bit value all at once rather than a byte at a time. This works by | |
138 | * creating a mask from the top bit in each byte and using that to | |
139 | * conditionally apply the XOR of 0x1d. | |
140 | */ | |
141 | #define VDEV_RAIDZ_64MUL_2(x, mask) \ | |
142 | { \ | |
143 | (mask) = (x) & 0x8080808080808080ULL; \ | |
144 | (mask) = ((mask) << 1) - ((mask) >> 7); \ | |
145 | (x) = (((x) << 1) & 0xfefefefefefefefeULL) ^ \ | |
c5b3a7bb | 146 | ((mask) & 0x1d1d1d1d1d1d1d1dULL); \ |
45d1cae3 | 147 | } |
34dc7c2f | 148 | |
45d1cae3 BB |
149 | #define VDEV_RAIDZ_64MUL_4(x, mask) \ |
150 | { \ | |
151 | VDEV_RAIDZ_64MUL_2((x), mask); \ | |
152 | VDEV_RAIDZ_64MUL_2((x), mask); \ | |
153 | } | |
34dc7c2f | 154 | |
45d1cae3 BB |
155 | /* |
156 | * Force reconstruction to use the general purpose method. | |
157 | */ | |
158 | int vdev_raidz_default_to_general; | |
34dc7c2f BB |
159 | |
160 | /* | |
161 | * These two tables represent powers and logs of 2 in the Galois field defined | |
162 | * above. These values were computed by repeatedly multiplying by 2 as above. | |
163 | */ | |
164 | static const uint8_t vdev_raidz_pow2[256] = { | |
165 | 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, | |
166 | 0x1d, 0x3a, 0x74, 0xe8, 0xcd, 0x87, 0x13, 0x26, | |
167 | 0x4c, 0x98, 0x2d, 0x5a, 0xb4, 0x75, 0xea, 0xc9, | |
168 | 0x8f, 0x03, 0x06, 0x0c, 0x18, 0x30, 0x60, 0xc0, | |
169 | 0x9d, 0x27, 0x4e, 0x9c, 0x25, 0x4a, 0x94, 0x35, | |
170 | 0x6a, 0xd4, 0xb5, 0x77, 0xee, 0xc1, 0x9f, 0x23, | |
171 | 0x46, 0x8c, 0x05, 0x0a, 0x14, 0x28, 0x50, 0xa0, | |
172 | 0x5d, 0xba, 0x69, 0xd2, 0xb9, 0x6f, 0xde, 0xa1, | |
173 | 0x5f, 0xbe, 0x61, 0xc2, 0x99, 0x2f, 0x5e, 0xbc, | |
174 | 0x65, 0xca, 0x89, 0x0f, 0x1e, 0x3c, 0x78, 0xf0, | |
175 | 0xfd, 0xe7, 0xd3, 0xbb, 0x6b, 0xd6, 0xb1, 0x7f, | |
176 | 0xfe, 0xe1, 0xdf, 0xa3, 0x5b, 0xb6, 0x71, 0xe2, | |
177 | 0xd9, 0xaf, 0x43, 0x86, 0x11, 0x22, 0x44, 0x88, | |
178 | 0x0d, 0x1a, 0x34, 0x68, 0xd0, 0xbd, 0x67, 0xce, | |
179 | 0x81, 0x1f, 0x3e, 0x7c, 0xf8, 0xed, 0xc7, 0x93, | |
180 | 0x3b, 0x76, 0xec, 0xc5, 0x97, 0x33, 0x66, 0xcc, | |
181 | 0x85, 0x17, 0x2e, 0x5c, 0xb8, 0x6d, 0xda, 0xa9, | |
182 | 0x4f, 0x9e, 0x21, 0x42, 0x84, 0x15, 0x2a, 0x54, | |
183 | 0xa8, 0x4d, 0x9a, 0x29, 0x52, 0xa4, 0x55, 0xaa, | |
184 | 0x49, 0x92, 0x39, 0x72, 0xe4, 0xd5, 0xb7, 0x73, | |
185 | 0xe6, 0xd1, 0xbf, 0x63, 0xc6, 0x91, 0x3f, 0x7e, | |
186 | 0xfc, 0xe5, 0xd7, 0xb3, 0x7b, 0xf6, 0xf1, 0xff, | |
187 | 0xe3, 0xdb, 0xab, 0x4b, 0x96, 0x31, 0x62, 0xc4, | |
188 | 0x95, 0x37, 0x6e, 0xdc, 0xa5, 0x57, 0xae, 0x41, | |
189 | 0x82, 0x19, 0x32, 0x64, 0xc8, 0x8d, 0x07, 0x0e, | |
190 | 0x1c, 0x38, 0x70, 0xe0, 0xdd, 0xa7, 0x53, 0xa6, | |
191 | 0x51, 0xa2, 0x59, 0xb2, 0x79, 0xf2, 0xf9, 0xef, | |
192 | 0xc3, 0x9b, 0x2b, 0x56, 0xac, 0x45, 0x8a, 0x09, | |
193 | 0x12, 0x24, 0x48, 0x90, 0x3d, 0x7a, 0xf4, 0xf5, | |
194 | 0xf7, 0xf3, 0xfb, 0xeb, 0xcb, 0x8b, 0x0b, 0x16, | |
195 | 0x2c, 0x58, 0xb0, 0x7d, 0xfa, 0xe9, 0xcf, 0x83, | |
196 | 0x1b, 0x36, 0x6c, 0xd8, 0xad, 0x47, 0x8e, 0x01 | |
197 | }; | |
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, | |
231 | }; | |
232 | ||
428870ff BB |
233 | static void vdev_raidz_generate_parity(raidz_map_t *rm); |
234 | ||
34dc7c2f BB |
235 | /* |
236 | * Multiply a given number by 2 raised to the given power. | |
237 | */ | |
238 | static uint8_t | |
239 | vdev_raidz_exp2(uint_t a, int exp) | |
240 | { | |
241 | if (a == 0) | |
242 | return (0); | |
243 | ||
244 | ASSERT(exp >= 0); | |
245 | ASSERT(vdev_raidz_log2[a] > 0 || a == 1); | |
246 | ||
247 | exp += vdev_raidz_log2[a]; | |
248 | if (exp > 255) | |
249 | exp -= 255; | |
250 | ||
251 | return (vdev_raidz_pow2[exp]); | |
252 | } | |
253 | ||
b128c09f | 254 | static void |
428870ff | 255 | vdev_raidz_map_free(raidz_map_t *rm) |
b128c09f | 256 | { |
b128c09f | 257 | int c; |
428870ff | 258 | size_t size; |
b128c09f | 259 | |
428870ff | 260 | for (c = 0; c < rm->rm_firstdatacol; c++) { |
b128c09f BB |
261 | zio_buf_free(rm->rm_col[c].rc_data, rm->rm_col[c].rc_size); |
262 | ||
428870ff BB |
263 | if (rm->rm_col[c].rc_gdata != NULL) |
264 | zio_buf_free(rm->rm_col[c].rc_gdata, | |
265 | rm->rm_col[c].rc_size); | |
266 | } | |
267 | ||
268 | size = 0; | |
269 | for (c = rm->rm_firstdatacol; c < rm->rm_cols; c++) | |
270 | size += rm->rm_col[c].rc_size; | |
271 | ||
272 | if (rm->rm_datacopy != NULL) | |
273 | zio_buf_free(rm->rm_datacopy, size); | |
274 | ||
45d1cae3 | 275 | kmem_free(rm, offsetof(raidz_map_t, rm_col[rm->rm_scols])); |
b128c09f BB |
276 | } |
277 | ||
428870ff BB |
278 | static void |
279 | vdev_raidz_map_free_vsd(zio_t *zio) | |
280 | { | |
281 | raidz_map_t *rm = zio->io_vsd; | |
282 | ||
283 | ASSERT3U(rm->rm_freed, ==, 0); | |
284 | rm->rm_freed = 1; | |
285 | ||
286 | if (rm->rm_reports == 0) | |
287 | vdev_raidz_map_free(rm); | |
288 | } | |
289 | ||
290 | /*ARGSUSED*/ | |
291 | static void | |
292 | vdev_raidz_cksum_free(void *arg, size_t ignored) | |
293 | { | |
294 | raidz_map_t *rm = arg; | |
295 | ||
296 | ASSERT3U(rm->rm_reports, >, 0); | |
297 | ||
298 | if (--rm->rm_reports == 0 && rm->rm_freed != 0) | |
299 | vdev_raidz_map_free(rm); | |
300 | } | |
301 | ||
302 | static void | |
303 | vdev_raidz_cksum_finish(zio_cksum_report_t *zcr, const void *good_data) | |
304 | { | |
305 | raidz_map_t *rm = zcr->zcr_cbdata; | |
306 | size_t c = zcr->zcr_cbinfo; | |
307 | size_t x; | |
308 | ||
309 | const char *good = NULL; | |
310 | const char *bad = rm->rm_col[c].rc_data; | |
311 | ||
312 | if (good_data == NULL) { | |
313 | zfs_ereport_finish_checksum(zcr, NULL, NULL, B_FALSE); | |
314 | return; | |
315 | } | |
316 | ||
317 | if (c < rm->rm_firstdatacol) { | |
318 | /* | |
319 | * The first time through, calculate the parity blocks for | |
320 | * the good data (this relies on the fact that the good | |
321 | * data never changes for a given logical ZIO) | |
322 | */ | |
323 | if (rm->rm_col[0].rc_gdata == NULL) { | |
324 | char *bad_parity[VDEV_RAIDZ_MAXPARITY]; | |
325 | char *buf; | |
326 | ||
327 | /* | |
328 | * Set up the rm_col[]s to generate the parity for | |
329 | * good_data, first saving the parity bufs and | |
330 | * replacing them with buffers to hold the result. | |
331 | */ | |
332 | for (x = 0; x < rm->rm_firstdatacol; x++) { | |
333 | bad_parity[x] = rm->rm_col[x].rc_data; | |
334 | rm->rm_col[x].rc_data = rm->rm_col[x].rc_gdata = | |
335 | zio_buf_alloc(rm->rm_col[x].rc_size); | |
336 | } | |
337 | ||
338 | /* fill in the data columns from good_data */ | |
339 | buf = (char *)good_data; | |
340 | for (; x < rm->rm_cols; x++) { | |
341 | rm->rm_col[x].rc_data = buf; | |
342 | buf += rm->rm_col[x].rc_size; | |
343 | } | |
344 | ||
345 | /* | |
346 | * Construct the parity from the good data. | |
347 | */ | |
348 | vdev_raidz_generate_parity(rm); | |
349 | ||
350 | /* restore everything back to its original state */ | |
351 | for (x = 0; x < rm->rm_firstdatacol; x++) | |
352 | rm->rm_col[x].rc_data = bad_parity[x]; | |
353 | ||
354 | buf = rm->rm_datacopy; | |
355 | for (x = rm->rm_firstdatacol; x < rm->rm_cols; x++) { | |
356 | rm->rm_col[x].rc_data = buf; | |
357 | buf += rm->rm_col[x].rc_size; | |
358 | } | |
359 | } | |
360 | ||
361 | ASSERT3P(rm->rm_col[c].rc_gdata, !=, NULL); | |
362 | good = rm->rm_col[c].rc_gdata; | |
363 | } else { | |
364 | /* adjust good_data to point at the start of our column */ | |
365 | good = good_data; | |
366 | ||
367 | for (x = rm->rm_firstdatacol; x < c; x++) | |
368 | good += rm->rm_col[x].rc_size; | |
369 | } | |
370 | ||
371 | /* we drop the ereport if it ends up that the data was good */ | |
372 | zfs_ereport_finish_checksum(zcr, good, bad, B_TRUE); | |
373 | } | |
374 | ||
375 | /* | |
376 | * Invoked indirectly by zfs_ereport_start_checksum(), called | |
377 | * below when our read operation fails completely. The main point | |
378 | * is to keep a copy of everything we read from disk, so that at | |
379 | * vdev_raidz_cksum_finish() time we can compare it with the good data. | |
380 | */ | |
381 | static void | |
382 | vdev_raidz_cksum_report(zio_t *zio, zio_cksum_report_t *zcr, void *arg) | |
383 | { | |
384 | size_t c = (size_t)(uintptr_t)arg; | |
385 | caddr_t buf; | |
386 | ||
387 | raidz_map_t *rm = zio->io_vsd; | |
388 | size_t size; | |
389 | ||
390 | /* set up the report and bump the refcount */ | |
391 | zcr->zcr_cbdata = rm; | |
392 | zcr->zcr_cbinfo = c; | |
393 | zcr->zcr_finish = vdev_raidz_cksum_finish; | |
394 | zcr->zcr_free = vdev_raidz_cksum_free; | |
395 | ||
396 | rm->rm_reports++; | |
397 | ASSERT3U(rm->rm_reports, >, 0); | |
398 | ||
399 | if (rm->rm_datacopy != NULL) | |
400 | return; | |
401 | ||
402 | /* | |
403 | * It's the first time we're called for this raidz_map_t, so we need | |
404 | * to copy the data aside; there's no guarantee that our zio's buffer | |
405 | * won't be re-used for something else. | |
406 | * | |
407 | * Our parity data is already in separate buffers, so there's no need | |
408 | * to copy them. | |
409 | */ | |
410 | ||
411 | size = 0; | |
412 | for (c = rm->rm_firstdatacol; c < rm->rm_cols; c++) | |
413 | size += rm->rm_col[c].rc_size; | |
414 | ||
415 | buf = rm->rm_datacopy = zio_buf_alloc(size); | |
416 | ||
417 | for (c = rm->rm_firstdatacol; c < rm->rm_cols; c++) { | |
418 | raidz_col_t *col = &rm->rm_col[c]; | |
419 | ||
420 | bcopy(col->rc_data, buf, col->rc_size); | |
421 | col->rc_data = buf; | |
422 | ||
423 | buf += col->rc_size; | |
424 | } | |
425 | ASSERT3P(buf - (caddr_t)rm->rm_datacopy, ==, size); | |
426 | } | |
427 | ||
428 | static const zio_vsd_ops_t vdev_raidz_vsd_ops = { | |
429 | vdev_raidz_map_free_vsd, | |
430 | vdev_raidz_cksum_report | |
431 | }; | |
432 | ||
34dc7c2f BB |
433 | static raidz_map_t * |
434 | vdev_raidz_map_alloc(zio_t *zio, uint64_t unit_shift, uint64_t dcols, | |
435 | uint64_t nparity) | |
436 | { | |
437 | raidz_map_t *rm; | |
438 | uint64_t b = zio->io_offset >> unit_shift; | |
439 | uint64_t s = zio->io_size >> unit_shift; | |
440 | uint64_t f = b % dcols; | |
441 | uint64_t o = (b / dcols) << unit_shift; | |
45d1cae3 | 442 | uint64_t q, r, c, bc, col, acols, scols, coff, devidx, asize, tot; |
34dc7c2f BB |
443 | |
444 | q = s / (dcols - nparity); | |
445 | r = s - q * (dcols - nparity); | |
446 | bc = (r == 0 ? 0 : r + nparity); | |
45d1cae3 BB |
447 | tot = s + nparity * (q + (r == 0 ? 0 : 1)); |
448 | ||
449 | if (q == 0) { | |
450 | acols = bc; | |
451 | scols = MIN(dcols, roundup(bc, nparity + 1)); | |
452 | } else { | |
453 | acols = dcols; | |
454 | scols = dcols; | |
455 | } | |
34dc7c2f | 456 | |
45d1cae3 | 457 | ASSERT3U(acols, <=, scols); |
34dc7c2f | 458 | |
45d1cae3 | 459 | rm = kmem_alloc(offsetof(raidz_map_t, rm_col[scols]), KM_SLEEP); |
34dc7c2f BB |
460 | |
461 | rm->rm_cols = acols; | |
45d1cae3 | 462 | rm->rm_scols = scols; |
34dc7c2f | 463 | rm->rm_bigcols = bc; |
428870ff | 464 | rm->rm_skipstart = bc; |
34dc7c2f BB |
465 | rm->rm_missingdata = 0; |
466 | rm->rm_missingparity = 0; | |
467 | rm->rm_firstdatacol = nparity; | |
428870ff BB |
468 | rm->rm_datacopy = NULL; |
469 | rm->rm_reports = 0; | |
470 | rm->rm_freed = 0; | |
471 | rm->rm_ecksuminjected = 0; | |
34dc7c2f | 472 | |
45d1cae3 BB |
473 | asize = 0; |
474 | ||
475 | for (c = 0; c < scols; c++) { | |
34dc7c2f BB |
476 | col = f + c; |
477 | coff = o; | |
478 | if (col >= dcols) { | |
479 | col -= dcols; | |
480 | coff += 1ULL << unit_shift; | |
481 | } | |
482 | rm->rm_col[c].rc_devidx = col; | |
483 | rm->rm_col[c].rc_offset = coff; | |
34dc7c2f | 484 | rm->rm_col[c].rc_data = NULL; |
428870ff | 485 | rm->rm_col[c].rc_gdata = NULL; |
34dc7c2f BB |
486 | rm->rm_col[c].rc_error = 0; |
487 | rm->rm_col[c].rc_tried = 0; | |
488 | rm->rm_col[c].rc_skipped = 0; | |
45d1cae3 BB |
489 | |
490 | if (c >= acols) | |
491 | rm->rm_col[c].rc_size = 0; | |
492 | else if (c < bc) | |
493 | rm->rm_col[c].rc_size = (q + 1) << unit_shift; | |
494 | else | |
495 | rm->rm_col[c].rc_size = q << unit_shift; | |
496 | ||
497 | asize += rm->rm_col[c].rc_size; | |
34dc7c2f BB |
498 | } |
499 | ||
45d1cae3 BB |
500 | ASSERT3U(asize, ==, tot << unit_shift); |
501 | rm->rm_asize = roundup(asize, (nparity + 1) << unit_shift); | |
428870ff BB |
502 | rm->rm_nskip = roundup(tot, nparity + 1) - tot; |
503 | ASSERT3U(rm->rm_asize - asize, ==, rm->rm_nskip << unit_shift); | |
504 | ASSERT3U(rm->rm_nskip, <=, nparity); | |
34dc7c2f BB |
505 | |
506 | for (c = 0; c < rm->rm_firstdatacol; c++) | |
507 | rm->rm_col[c].rc_data = zio_buf_alloc(rm->rm_col[c].rc_size); | |
508 | ||
509 | rm->rm_col[c].rc_data = zio->io_data; | |
510 | ||
511 | for (c = c + 1; c < acols; c++) | |
512 | rm->rm_col[c].rc_data = (char *)rm->rm_col[c - 1].rc_data + | |
513 | rm->rm_col[c - 1].rc_size; | |
514 | ||
515 | /* | |
516 | * If all data stored spans all columns, there's a danger that parity | |
517 | * will always be on the same device and, since parity isn't read | |
518 | * during normal operation, that that device's I/O bandwidth won't be | |
519 | * used effectively. We therefore switch the parity every 1MB. | |
520 | * | |
521 | * ... at least that was, ostensibly, the theory. As a practical | |
522 | * matter unless we juggle the parity between all devices evenly, we | |
523 | * won't see any benefit. Further, occasional writes that aren't a | |
524 | * multiple of the LCM of the number of children and the minimum | |
525 | * stripe width are sufficient to avoid pessimal behavior. | |
526 | * Unfortunately, this decision created an implicit on-disk format | |
527 | * requirement that we need to support for all eternity, but only | |
528 | * for single-parity RAID-Z. | |
428870ff BB |
529 | * |
530 | * If we intend to skip a sector in the zeroth column for padding | |
531 | * we must make sure to note this swap. We will never intend to | |
532 | * skip the first column since at least one data and one parity | |
533 | * column must appear in each row. | |
34dc7c2f BB |
534 | */ |
535 | ASSERT(rm->rm_cols >= 2); | |
536 | ASSERT(rm->rm_col[0].rc_size == rm->rm_col[1].rc_size); | |
537 | ||
538 | if (rm->rm_firstdatacol == 1 && (zio->io_offset & (1ULL << 20))) { | |
539 | devidx = rm->rm_col[0].rc_devidx; | |
540 | o = rm->rm_col[0].rc_offset; | |
541 | rm->rm_col[0].rc_devidx = rm->rm_col[1].rc_devidx; | |
542 | rm->rm_col[0].rc_offset = rm->rm_col[1].rc_offset; | |
543 | rm->rm_col[1].rc_devidx = devidx; | |
544 | rm->rm_col[1].rc_offset = o; | |
428870ff BB |
545 | |
546 | if (rm->rm_skipstart == 0) | |
547 | rm->rm_skipstart = 1; | |
34dc7c2f BB |
548 | } |
549 | ||
550 | zio->io_vsd = rm; | |
428870ff | 551 | zio->io_vsd_ops = &vdev_raidz_vsd_ops; |
34dc7c2f BB |
552 | return (rm); |
553 | } | |
554 | ||
34dc7c2f BB |
555 | static void |
556 | vdev_raidz_generate_parity_p(raidz_map_t *rm) | |
557 | { | |
558 | uint64_t *p, *src, pcount, ccount, i; | |
559 | int c; | |
560 | ||
561 | pcount = rm->rm_col[VDEV_RAIDZ_P].rc_size / sizeof (src[0]); | |
562 | ||
563 | for (c = rm->rm_firstdatacol; c < rm->rm_cols; c++) { | |
564 | src = rm->rm_col[c].rc_data; | |
565 | p = rm->rm_col[VDEV_RAIDZ_P].rc_data; | |
566 | ccount = rm->rm_col[c].rc_size / sizeof (src[0]); | |
567 | ||
568 | if (c == rm->rm_firstdatacol) { | |
569 | ASSERT(ccount == pcount); | |
45d1cae3 | 570 | for (i = 0; i < ccount; i++, src++, p++) { |
34dc7c2f BB |
571 | *p = *src; |
572 | } | |
573 | } else { | |
574 | ASSERT(ccount <= pcount); | |
45d1cae3 | 575 | for (i = 0; i < ccount; i++, src++, p++) { |
34dc7c2f BB |
576 | *p ^= *src; |
577 | } | |
578 | } | |
579 | } | |
580 | } | |
581 | ||
582 | static void | |
583 | vdev_raidz_generate_parity_pq(raidz_map_t *rm) | |
584 | { | |
45d1cae3 | 585 | uint64_t *p, *q, *src, pcnt, ccnt, mask, i; |
34dc7c2f BB |
586 | int c; |
587 | ||
45d1cae3 | 588 | pcnt = rm->rm_col[VDEV_RAIDZ_P].rc_size / sizeof (src[0]); |
34dc7c2f BB |
589 | ASSERT(rm->rm_col[VDEV_RAIDZ_P].rc_size == |
590 | rm->rm_col[VDEV_RAIDZ_Q].rc_size); | |
591 | ||
592 | for (c = rm->rm_firstdatacol; c < rm->rm_cols; c++) { | |
593 | src = rm->rm_col[c].rc_data; | |
594 | p = rm->rm_col[VDEV_RAIDZ_P].rc_data; | |
595 | q = rm->rm_col[VDEV_RAIDZ_Q].rc_data; | |
45d1cae3 BB |
596 | |
597 | ccnt = rm->rm_col[c].rc_size / sizeof (src[0]); | |
34dc7c2f BB |
598 | |
599 | if (c == rm->rm_firstdatacol) { | |
45d1cae3 BB |
600 | ASSERT(ccnt == pcnt || ccnt == 0); |
601 | for (i = 0; i < ccnt; i++, src++, p++, q++) { | |
34dc7c2f | 602 | *p = *src; |
45d1cae3 | 603 | *q = *src; |
34dc7c2f | 604 | } |
45d1cae3 | 605 | for (; i < pcnt; i++, src++, p++, q++) { |
34dc7c2f | 606 | *p = 0; |
45d1cae3 | 607 | *q = 0; |
34dc7c2f BB |
608 | } |
609 | } else { | |
45d1cae3 | 610 | ASSERT(ccnt <= pcnt); |
34dc7c2f BB |
611 | |
612 | /* | |
45d1cae3 BB |
613 | * Apply the algorithm described above by multiplying |
614 | * the previous result and adding in the new value. | |
34dc7c2f | 615 | */ |
45d1cae3 BB |
616 | for (i = 0; i < ccnt; i++, src++, p++, q++) { |
617 | *p ^= *src; | |
618 | ||
619 | VDEV_RAIDZ_64MUL_2(*q, mask); | |
34dc7c2f | 620 | *q ^= *src; |
45d1cae3 BB |
621 | } |
622 | ||
623 | /* | |
624 | * Treat short columns as though they are full of 0s. | |
625 | * Note that there's therefore nothing needed for P. | |
626 | */ | |
627 | for (; i < pcnt; i++, q++) { | |
628 | VDEV_RAIDZ_64MUL_2(*q, mask); | |
629 | } | |
630 | } | |
631 | } | |
632 | } | |
633 | ||
634 | static void | |
635 | vdev_raidz_generate_parity_pqr(raidz_map_t *rm) | |
636 | { | |
637 | uint64_t *p, *q, *r, *src, pcnt, ccnt, mask, i; | |
638 | int c; | |
639 | ||
640 | pcnt = rm->rm_col[VDEV_RAIDZ_P].rc_size / sizeof (src[0]); | |
641 | ASSERT(rm->rm_col[VDEV_RAIDZ_P].rc_size == | |
642 | rm->rm_col[VDEV_RAIDZ_Q].rc_size); | |
643 | ASSERT(rm->rm_col[VDEV_RAIDZ_P].rc_size == | |
644 | rm->rm_col[VDEV_RAIDZ_R].rc_size); | |
645 | ||
646 | for (c = rm->rm_firstdatacol; c < rm->rm_cols; c++) { | |
647 | src = rm->rm_col[c].rc_data; | |
648 | p = rm->rm_col[VDEV_RAIDZ_P].rc_data; | |
649 | q = rm->rm_col[VDEV_RAIDZ_Q].rc_data; | |
650 | r = rm->rm_col[VDEV_RAIDZ_R].rc_data; | |
651 | ||
652 | ccnt = rm->rm_col[c].rc_size / sizeof (src[0]); | |
653 | ||
654 | if (c == rm->rm_firstdatacol) { | |
655 | ASSERT(ccnt == pcnt || ccnt == 0); | |
656 | for (i = 0; i < ccnt; i++, src++, p++, q++, r++) { | |
657 | *p = *src; | |
658 | *q = *src; | |
659 | *r = *src; | |
660 | } | |
661 | for (; i < pcnt; i++, src++, p++, q++, r++) { | |
662 | *p = 0; | |
663 | *q = 0; | |
664 | *r = 0; | |
665 | } | |
666 | } else { | |
667 | ASSERT(ccnt <= pcnt); | |
668 | ||
669 | /* | |
670 | * Apply the algorithm described above by multiplying | |
671 | * the previous result and adding in the new value. | |
672 | */ | |
673 | for (i = 0; i < ccnt; i++, src++, p++, q++, r++) { | |
34dc7c2f | 674 | *p ^= *src; |
45d1cae3 BB |
675 | |
676 | VDEV_RAIDZ_64MUL_2(*q, mask); | |
677 | *q ^= *src; | |
678 | ||
679 | VDEV_RAIDZ_64MUL_4(*r, mask); | |
680 | *r ^= *src; | |
34dc7c2f BB |
681 | } |
682 | ||
683 | /* | |
684 | * Treat short columns as though they are full of 0s. | |
45d1cae3 | 685 | * Note that there's therefore nothing needed for P. |
34dc7c2f | 686 | */ |
45d1cae3 BB |
687 | for (; i < pcnt; i++, q++, r++) { |
688 | VDEV_RAIDZ_64MUL_2(*q, mask); | |
689 | VDEV_RAIDZ_64MUL_4(*r, mask); | |
34dc7c2f BB |
690 | } |
691 | } | |
692 | } | |
693 | } | |
694 | ||
45d1cae3 BB |
695 | /* |
696 | * Generate RAID parity in the first virtual columns according to the number of | |
697 | * parity columns available. | |
698 | */ | |
34dc7c2f | 699 | static void |
45d1cae3 BB |
700 | vdev_raidz_generate_parity(raidz_map_t *rm) |
701 | { | |
702 | switch (rm->rm_firstdatacol) { | |
703 | case 1: | |
704 | vdev_raidz_generate_parity_p(rm); | |
705 | break; | |
706 | case 2: | |
707 | vdev_raidz_generate_parity_pq(rm); | |
708 | break; | |
709 | case 3: | |
710 | vdev_raidz_generate_parity_pqr(rm); | |
711 | break; | |
712 | default: | |
713 | cmn_err(CE_PANIC, "invalid RAID-Z configuration"); | |
714 | } | |
715 | } | |
716 | ||
717 | static int | |
718 | vdev_raidz_reconstruct_p(raidz_map_t *rm, int *tgts, int ntgts) | |
34dc7c2f BB |
719 | { |
720 | uint64_t *dst, *src, xcount, ccount, count, i; | |
45d1cae3 | 721 | int x = tgts[0]; |
34dc7c2f BB |
722 | int c; |
723 | ||
45d1cae3 BB |
724 | ASSERT(ntgts == 1); |
725 | ASSERT(x >= rm->rm_firstdatacol); | |
726 | ASSERT(x < rm->rm_cols); | |
727 | ||
34dc7c2f BB |
728 | xcount = rm->rm_col[x].rc_size / sizeof (src[0]); |
729 | ASSERT(xcount <= rm->rm_col[VDEV_RAIDZ_P].rc_size / sizeof (src[0])); | |
730 | ASSERT(xcount > 0); | |
731 | ||
732 | src = rm->rm_col[VDEV_RAIDZ_P].rc_data; | |
733 | dst = rm->rm_col[x].rc_data; | |
734 | for (i = 0; i < xcount; i++, dst++, src++) { | |
735 | *dst = *src; | |
736 | } | |
737 | ||
738 | for (c = rm->rm_firstdatacol; c < rm->rm_cols; c++) { | |
739 | src = rm->rm_col[c].rc_data; | |
740 | dst = rm->rm_col[x].rc_data; | |
741 | ||
742 | if (c == x) | |
743 | continue; | |
744 | ||
745 | ccount = rm->rm_col[c].rc_size / sizeof (src[0]); | |
746 | count = MIN(ccount, xcount); | |
747 | ||
748 | for (i = 0; i < count; i++, dst++, src++) { | |
749 | *dst ^= *src; | |
750 | } | |
751 | } | |
45d1cae3 BB |
752 | |
753 | return (1 << VDEV_RAIDZ_P); | |
34dc7c2f BB |
754 | } |
755 | ||
45d1cae3 BB |
756 | static int |
757 | vdev_raidz_reconstruct_q(raidz_map_t *rm, int *tgts, int ntgts) | |
34dc7c2f BB |
758 | { |
759 | uint64_t *dst, *src, xcount, ccount, count, mask, i; | |
760 | uint8_t *b; | |
45d1cae3 | 761 | int x = tgts[0]; |
34dc7c2f BB |
762 | int c, j, exp; |
763 | ||
45d1cae3 BB |
764 | ASSERT(ntgts == 1); |
765 | ||
34dc7c2f BB |
766 | xcount = rm->rm_col[x].rc_size / sizeof (src[0]); |
767 | ASSERT(xcount <= rm->rm_col[VDEV_RAIDZ_Q].rc_size / sizeof (src[0])); | |
768 | ||
769 | for (c = rm->rm_firstdatacol; c < rm->rm_cols; c++) { | |
770 | src = rm->rm_col[c].rc_data; | |
771 | dst = rm->rm_col[x].rc_data; | |
772 | ||
773 | if (c == x) | |
774 | ccount = 0; | |
775 | else | |
776 | ccount = rm->rm_col[c].rc_size / sizeof (src[0]); | |
777 | ||
778 | count = MIN(ccount, xcount); | |
779 | ||
780 | if (c == rm->rm_firstdatacol) { | |
781 | for (i = 0; i < count; i++, dst++, src++) { | |
782 | *dst = *src; | |
783 | } | |
784 | for (; i < xcount; i++, dst++) { | |
785 | *dst = 0; | |
786 | } | |
787 | ||
788 | } else { | |
34dc7c2f | 789 | for (i = 0; i < count; i++, dst++, src++) { |
45d1cae3 | 790 | VDEV_RAIDZ_64MUL_2(*dst, mask); |
34dc7c2f BB |
791 | *dst ^= *src; |
792 | } | |
793 | ||
794 | for (; i < xcount; i++, dst++) { | |
45d1cae3 | 795 | VDEV_RAIDZ_64MUL_2(*dst, mask); |
34dc7c2f BB |
796 | } |
797 | } | |
798 | } | |
799 | ||
800 | src = rm->rm_col[VDEV_RAIDZ_Q].rc_data; | |
801 | dst = rm->rm_col[x].rc_data; | |
802 | exp = 255 - (rm->rm_cols - 1 - x); | |
803 | ||
804 | for (i = 0; i < xcount; i++, dst++, src++) { | |
805 | *dst ^= *src; | |
806 | for (j = 0, b = (uint8_t *)dst; j < 8; j++, b++) { | |
807 | *b = vdev_raidz_exp2(*b, exp); | |
808 | } | |
809 | } | |
45d1cae3 BB |
810 | |
811 | return (1 << VDEV_RAIDZ_Q); | |
34dc7c2f BB |
812 | } |
813 | ||
45d1cae3 BB |
814 | static int |
815 | vdev_raidz_reconstruct_pq(raidz_map_t *rm, int *tgts, int ntgts) | |
34dc7c2f BB |
816 | { |
817 | uint8_t *p, *q, *pxy, *qxy, *xd, *yd, tmp, a, b, aexp, bexp; | |
818 | void *pdata, *qdata; | |
819 | uint64_t xsize, ysize, i; | |
45d1cae3 BB |
820 | int x = tgts[0]; |
821 | int y = tgts[1]; | |
34dc7c2f | 822 | |
45d1cae3 | 823 | ASSERT(ntgts == 2); |
34dc7c2f BB |
824 | ASSERT(x < y); |
825 | ASSERT(x >= rm->rm_firstdatacol); | |
826 | ASSERT(y < rm->rm_cols); | |
827 | ||
828 | ASSERT(rm->rm_col[x].rc_size >= rm->rm_col[y].rc_size); | |
829 | ||
830 | /* | |
831 | * Move the parity data aside -- we're going to compute parity as | |
832 | * though columns x and y were full of zeros -- Pxy and Qxy. We want to | |
833 | * reuse the parity generation mechanism without trashing the actual | |
834 | * parity so we make those columns appear to be full of zeros by | |
835 | * setting their lengths to zero. | |
836 | */ | |
837 | pdata = rm->rm_col[VDEV_RAIDZ_P].rc_data; | |
838 | qdata = rm->rm_col[VDEV_RAIDZ_Q].rc_data; | |
839 | xsize = rm->rm_col[x].rc_size; | |
840 | ysize = rm->rm_col[y].rc_size; | |
841 | ||
842 | rm->rm_col[VDEV_RAIDZ_P].rc_data = | |
843 | zio_buf_alloc(rm->rm_col[VDEV_RAIDZ_P].rc_size); | |
844 | rm->rm_col[VDEV_RAIDZ_Q].rc_data = | |
845 | zio_buf_alloc(rm->rm_col[VDEV_RAIDZ_Q].rc_size); | |
846 | rm->rm_col[x].rc_size = 0; | |
847 | rm->rm_col[y].rc_size = 0; | |
848 | ||
849 | vdev_raidz_generate_parity_pq(rm); | |
850 | ||
851 | rm->rm_col[x].rc_size = xsize; | |
852 | rm->rm_col[y].rc_size = ysize; | |
853 | ||
854 | p = pdata; | |
855 | q = qdata; | |
856 | pxy = rm->rm_col[VDEV_RAIDZ_P].rc_data; | |
857 | qxy = rm->rm_col[VDEV_RAIDZ_Q].rc_data; | |
858 | xd = rm->rm_col[x].rc_data; | |
859 | yd = rm->rm_col[y].rc_data; | |
860 | ||
861 | /* | |
862 | * We now have: | |
863 | * Pxy = P + D_x + D_y | |
864 | * Qxy = Q + 2^(ndevs - 1 - x) * D_x + 2^(ndevs - 1 - y) * D_y | |
865 | * | |
866 | * We can then solve for D_x: | |
867 | * D_x = A * (P + Pxy) + B * (Q + Qxy) | |
868 | * where | |
869 | * A = 2^(x - y) * (2^(x - y) + 1)^-1 | |
870 | * B = 2^(ndevs - 1 - x) * (2^(x - y) + 1)^-1 | |
871 | * | |
872 | * With D_x in hand, we can easily solve for D_y: | |
873 | * D_y = P + Pxy + D_x | |
874 | */ | |
875 | ||
876 | a = vdev_raidz_pow2[255 + x - y]; | |
877 | b = vdev_raidz_pow2[255 - (rm->rm_cols - 1 - x)]; | |
878 | tmp = 255 - vdev_raidz_log2[a ^ 1]; | |
879 | ||
880 | aexp = vdev_raidz_log2[vdev_raidz_exp2(a, tmp)]; | |
881 | bexp = vdev_raidz_log2[vdev_raidz_exp2(b, tmp)]; | |
882 | ||
883 | for (i = 0; i < xsize; i++, p++, q++, pxy++, qxy++, xd++, yd++) { | |
884 | *xd = vdev_raidz_exp2(*p ^ *pxy, aexp) ^ | |
885 | vdev_raidz_exp2(*q ^ *qxy, bexp); | |
886 | ||
887 | if (i < ysize) | |
888 | *yd = *p ^ *pxy ^ *xd; | |
889 | } | |
890 | ||
891 | zio_buf_free(rm->rm_col[VDEV_RAIDZ_P].rc_data, | |
892 | rm->rm_col[VDEV_RAIDZ_P].rc_size); | |
893 | zio_buf_free(rm->rm_col[VDEV_RAIDZ_Q].rc_data, | |
894 | rm->rm_col[VDEV_RAIDZ_Q].rc_size); | |
895 | ||
896 | /* | |
897 | * Restore the saved parity data. | |
898 | */ | |
899 | rm->rm_col[VDEV_RAIDZ_P].rc_data = pdata; | |
900 | rm->rm_col[VDEV_RAIDZ_Q].rc_data = qdata; | |
45d1cae3 BB |
901 | |
902 | return ((1 << VDEV_RAIDZ_P) | (1 << VDEV_RAIDZ_Q)); | |
903 | } | |
904 | ||
905 | /* BEGIN CSTYLED */ | |
906 | /* | |
907 | * In the general case of reconstruction, we must solve the system of linear | |
908 | * equations defined by the coeffecients used to generate parity as well as | |
909 | * the contents of the data and parity disks. This can be expressed with | |
910 | * vectors for the original data (D) and the actual data (d) and parity (p) | |
911 | * and a matrix composed of the identity matrix (I) and a dispersal matrix (V): | |
912 | * | |
913 | * __ __ __ __ | |
914 | * | | __ __ | p_0 | | |
915 | * | V | | D_0 | | p_m-1 | | |
916 | * | | x | : | = | d_0 | | |
917 | * | I | | D_n-1 | | : | | |
918 | * | | ~~ ~~ | d_n-1 | | |
919 | * ~~ ~~ ~~ ~~ | |
920 | * | |
921 | * I is simply a square identity matrix of size n, and V is a vandermonde | |
922 | * matrix defined by the coeffecients we chose for the various parity columns | |
923 | * (1, 2, 4). Note that these values were chosen both for simplicity, speedy | |
924 | * computation as well as linear separability. | |
925 | * | |
926 | * __ __ __ __ | |
927 | * | 1 .. 1 1 1 | | p_0 | | |
928 | * | 2^n-1 .. 4 2 1 | __ __ | : | | |
929 | * | 4^n-1 .. 16 4 1 | | D_0 | | p_m-1 | | |
930 | * | 1 .. 0 0 0 | | D_1 | | d_0 | | |
931 | * | 0 .. 0 0 0 | x | D_2 | = | d_1 | | |
932 | * | : : : : | | : | | d_2 | | |
933 | * | 0 .. 1 0 0 | | D_n-1 | | : | | |
934 | * | 0 .. 0 1 0 | ~~ ~~ | : | | |
935 | * | 0 .. 0 0 1 | | d_n-1 | | |
936 | * ~~ ~~ ~~ ~~ | |
937 | * | |
938 | * Note that I, V, d, and p are known. To compute D, we must invert the | |
939 | * matrix and use the known data and parity values to reconstruct the unknown | |
940 | * data values. We begin by removing the rows in V|I and d|p that correspond | |
941 | * to failed or missing columns; we then make V|I square (n x n) and d|p | |
942 | * sized n by removing rows corresponding to unused parity from the bottom up | |
943 | * to generate (V|I)' and (d|p)'. We can then generate the inverse of (V|I)' | |
944 | * using Gauss-Jordan elimination. In the example below we use m=3 parity | |
945 | * columns, n=8 data columns, with errors in d_1, d_2, and p_1: | |
946 | * __ __ | |
947 | * | 1 1 1 1 1 1 1 1 | | |
948 | * | 128 64 32 16 8 4 2 1 | <-----+-+-- missing disks | |
949 | * | 19 205 116 29 64 16 4 1 | / / | |
950 | * | 1 0 0 0 0 0 0 0 | / / | |
951 | * | 0 1 0 0 0 0 0 0 | <--' / | |
952 | * (V|I) = | 0 0 1 0 0 0 0 0 | <---' | |
953 | * | 0 0 0 1 0 0 0 0 | | |
954 | * | 0 0 0 0 1 0 0 0 | | |
955 | * | 0 0 0 0 0 1 0 0 | | |
956 | * | 0 0 0 0 0 0 1 0 | | |
957 | * | 0 0 0 0 0 0 0 1 | | |
958 | * ~~ ~~ | |
959 | * __ __ | |
960 | * | 1 1 1 1 1 1 1 1 | | |
961 | * | 128 64 32 16 8 4 2 1 | | |
962 | * | 19 205 116 29 64 16 4 1 | | |
963 | * | 1 0 0 0 0 0 0 0 | | |
964 | * | 0 1 0 0 0 0 0 0 | | |
965 | * (V|I)' = | 0 0 1 0 0 0 0 0 | | |
966 | * | 0 0 0 1 0 0 0 0 | | |
967 | * | 0 0 0 0 1 0 0 0 | | |
968 | * | 0 0 0 0 0 1 0 0 | | |
969 | * | 0 0 0 0 0 0 1 0 | | |
970 | * | 0 0 0 0 0 0 0 1 | | |
971 | * ~~ ~~ | |
972 | * | |
973 | * Here we employ Gauss-Jordan elimination to find the inverse of (V|I)'. We | |
974 | * have carefully chosen the seed values 1, 2, and 4 to ensure that this | |
975 | * matrix is not singular. | |
976 | * __ __ | |
977 | * | 1 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 | | |
978 | * | 19 205 116 29 64 16 4 1 0 1 0 0 0 0 0 0 | | |
979 | * | 1 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 | | |
980 | * | 0 0 0 1 0 0 0 0 0 0 0 1 0 0 0 0 | | |
981 | * | 0 0 0 0 1 0 0 0 0 0 0 0 1 0 0 0 | | |
982 | * | 0 0 0 0 0 1 0 0 0 0 0 0 0 1 0 0 | | |
983 | * | 0 0 0 0 0 0 1 0 0 0 0 0 0 0 1 0 | | |
984 | * | 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 1 | | |
985 | * ~~ ~~ | |
986 | * __ __ | |
987 | * | 1 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 | | |
988 | * | 1 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 | | |
989 | * | 19 205 116 29 64 16 4 1 0 1 0 0 0 0 0 0 | | |
990 | * | 0 0 0 1 0 0 0 0 0 0 0 1 0 0 0 0 | | |
991 | * | 0 0 0 0 1 0 0 0 0 0 0 0 1 0 0 0 | | |
992 | * | 0 0 0 0 0 1 0 0 0 0 0 0 0 1 0 0 | | |
993 | * | 0 0 0 0 0 0 1 0 0 0 0 0 0 0 1 0 | | |
994 | * | 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 1 | | |
995 | * ~~ ~~ | |
996 | * __ __ | |
997 | * | 1 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 | | |
998 | * | 0 1 1 0 0 0 0 0 1 0 1 1 1 1 1 1 | | |
999 | * | 0 205 116 0 0 0 0 0 0 1 19 29 64 16 4 1 | | |
1000 | * | 0 0 0 1 0 0 0 0 0 0 0 1 0 0 0 0 | | |
1001 | * | 0 0 0 0 1 0 0 0 0 0 0 0 1 0 0 0 | | |
1002 | * | 0 0 0 0 0 1 0 0 0 0 0 0 0 1 0 0 | | |
1003 | * | 0 0 0 0 0 0 1 0 0 0 0 0 0 0 1 0 | | |
1004 | * | 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 1 | | |
1005 | * ~~ ~~ | |
1006 | * __ __ | |
1007 | * | 1 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 | | |
1008 | * | 0 1 1 0 0 0 0 0 1 0 1 1 1 1 1 1 | | |
1009 | * | 0 0 185 0 0 0 0 0 205 1 222 208 141 221 201 204 | | |
1010 | * | 0 0 0 1 0 0 0 0 0 0 0 1 0 0 0 0 | | |
1011 | * | 0 0 0 0 1 0 0 0 0 0 0 0 1 0 0 0 | | |
1012 | * | 0 0 0 0 0 1 0 0 0 0 0 0 0 1 0 0 | | |
1013 | * | 0 0 0 0 0 0 1 0 0 0 0 0 0 0 1 0 | | |
1014 | * | 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 1 | | |
1015 | * ~~ ~~ | |
1016 | * __ __ | |
1017 | * | 1 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 | | |
1018 | * | 0 1 1 0 0 0 0 0 1 0 1 1 1 1 1 1 | | |
1019 | * | 0 0 1 0 0 0 0 0 166 100 4 40 158 168 216 209 | | |
1020 | * | 0 0 0 1 0 0 0 0 0 0 0 1 0 0 0 0 | | |
1021 | * | 0 0 0 0 1 0 0 0 0 0 0 0 1 0 0 0 | | |
1022 | * | 0 0 0 0 0 1 0 0 0 0 0 0 0 1 0 0 | | |
1023 | * | 0 0 0 0 0 0 1 0 0 0 0 0 0 0 1 0 | | |
1024 | * | 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 1 | | |
1025 | * ~~ ~~ | |
1026 | * __ __ | |
1027 | * | 1 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 | | |
1028 | * | 0 1 0 0 0 0 0 0 167 100 5 41 159 169 217 208 | | |
1029 | * | 0 0 1 0 0 0 0 0 166 100 4 40 158 168 216 209 | | |
1030 | * | 0 0 0 1 0 0 0 0 0 0 0 1 0 0 0 0 | | |
1031 | * | 0 0 0 0 1 0 0 0 0 0 0 0 1 0 0 0 | | |
1032 | * | 0 0 0 0 0 1 0 0 0 0 0 0 0 1 0 0 | | |
1033 | * | 0 0 0 0 0 0 1 0 0 0 0 0 0 0 1 0 | | |
1034 | * | 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 1 | | |
1035 | * ~~ ~~ | |
1036 | * __ __ | |
1037 | * | 0 0 1 0 0 0 0 0 | | |
1038 | * | 167 100 5 41 159 169 217 208 | | |
1039 | * | 166 100 4 40 158 168 216 209 | | |
1040 | * (V|I)'^-1 = | 0 0 0 1 0 0 0 0 | | |
1041 | * | 0 0 0 0 1 0 0 0 | | |
1042 | * | 0 0 0 0 0 1 0 0 | | |
1043 | * | 0 0 0 0 0 0 1 0 | | |
1044 | * | 0 0 0 0 0 0 0 1 | | |
1045 | * ~~ ~~ | |
1046 | * | |
1047 | * We can then simply compute D = (V|I)'^-1 x (d|p)' to discover the values | |
1048 | * of the missing data. | |
1049 | * | |
1050 | * As is apparent from the example above, the only non-trivial rows in the | |
1051 | * inverse matrix correspond to the data disks that we're trying to | |
1052 | * reconstruct. Indeed, those are the only rows we need as the others would | |
1053 | * only be useful for reconstructing data known or assumed to be valid. For | |
1054 | * that reason, we only build the coefficients in the rows that correspond to | |
1055 | * targeted columns. | |
1056 | */ | |
1057 | /* END CSTYLED */ | |
1058 | ||
1059 | static void | |
1060 | vdev_raidz_matrix_init(raidz_map_t *rm, int n, int nmap, int *map, | |
1061 | uint8_t **rows) | |
1062 | { | |
1063 | int i, j; | |
1064 | int pow; | |
1065 | ||
1066 | ASSERT(n == rm->rm_cols - rm->rm_firstdatacol); | |
1067 | ||
1068 | /* | |
1069 | * Fill in the missing rows of interest. | |
1070 | */ | |
1071 | for (i = 0; i < nmap; i++) { | |
1072 | ASSERT3S(0, <=, map[i]); | |
1073 | ASSERT3S(map[i], <=, 2); | |
1074 | ||
1075 | pow = map[i] * n; | |
1076 | if (pow > 255) | |
1077 | pow -= 255; | |
1078 | ASSERT(pow <= 255); | |
1079 | ||
1080 | for (j = 0; j < n; j++) { | |
1081 | pow -= map[i]; | |
1082 | if (pow < 0) | |
1083 | pow += 255; | |
1084 | rows[i][j] = vdev_raidz_pow2[pow]; | |
1085 | } | |
1086 | } | |
1087 | } | |
1088 | ||
1089 | static void | |
1090 | vdev_raidz_matrix_invert(raidz_map_t *rm, int n, int nmissing, int *missing, | |
1091 | uint8_t **rows, uint8_t **invrows, const uint8_t *used) | |
1092 | { | |
1093 | int i, j, ii, jj; | |
1094 | uint8_t log; | |
1095 | ||
1096 | /* | |
1097 | * Assert that the first nmissing entries from the array of used | |
1098 | * columns correspond to parity columns and that subsequent entries | |
1099 | * correspond to data columns. | |
1100 | */ | |
1101 | for (i = 0; i < nmissing; i++) { | |
1102 | ASSERT3S(used[i], <, rm->rm_firstdatacol); | |
1103 | } | |
1104 | for (; i < n; i++) { | |
1105 | ASSERT3S(used[i], >=, rm->rm_firstdatacol); | |
1106 | } | |
1107 | ||
1108 | /* | |
1109 | * First initialize the storage where we'll compute the inverse rows. | |
1110 | */ | |
1111 | for (i = 0; i < nmissing; i++) { | |
1112 | for (j = 0; j < n; j++) { | |
1113 | invrows[i][j] = (i == j) ? 1 : 0; | |
1114 | } | |
1115 | } | |
1116 | ||
1117 | /* | |
1118 | * Subtract all trivial rows from the rows of consequence. | |
1119 | */ | |
1120 | for (i = 0; i < nmissing; i++) { | |
1121 | for (j = nmissing; j < n; j++) { | |
1122 | ASSERT3U(used[j], >=, rm->rm_firstdatacol); | |
1123 | jj = used[j] - rm->rm_firstdatacol; | |
1124 | ASSERT3S(jj, <, n); | |
1125 | invrows[i][j] = rows[i][jj]; | |
1126 | rows[i][jj] = 0; | |
1127 | } | |
1128 | } | |
1129 | ||
1130 | /* | |
1131 | * For each of the rows of interest, we must normalize it and subtract | |
1132 | * a multiple of it from the other rows. | |
1133 | */ | |
1134 | for (i = 0; i < nmissing; i++) { | |
1135 | for (j = 0; j < missing[i]; j++) { | |
1136 | ASSERT3U(rows[i][j], ==, 0); | |
1137 | } | |
1138 | ASSERT3U(rows[i][missing[i]], !=, 0); | |
1139 | ||
1140 | /* | |
1141 | * Compute the inverse of the first element and multiply each | |
1142 | * element in the row by that value. | |
1143 | */ | |
1144 | log = 255 - vdev_raidz_log2[rows[i][missing[i]]]; | |
1145 | ||
1146 | for (j = 0; j < n; j++) { | |
1147 | rows[i][j] = vdev_raidz_exp2(rows[i][j], log); | |
1148 | invrows[i][j] = vdev_raidz_exp2(invrows[i][j], log); | |
1149 | } | |
1150 | ||
1151 | for (ii = 0; ii < nmissing; ii++) { | |
1152 | if (i == ii) | |
1153 | continue; | |
1154 | ||
1155 | ASSERT3U(rows[ii][missing[i]], !=, 0); | |
1156 | ||
1157 | log = vdev_raidz_log2[rows[ii][missing[i]]]; | |
1158 | ||
1159 | for (j = 0; j < n; j++) { | |
1160 | rows[ii][j] ^= | |
1161 | vdev_raidz_exp2(rows[i][j], log); | |
1162 | invrows[ii][j] ^= | |
1163 | vdev_raidz_exp2(invrows[i][j], log); | |
1164 | } | |
1165 | } | |
1166 | } | |
1167 | ||
1168 | /* | |
1169 | * Verify that the data that is left in the rows are properly part of | |
1170 | * an identity matrix. | |
1171 | */ | |
1172 | for (i = 0; i < nmissing; i++) { | |
1173 | for (j = 0; j < n; j++) { | |
1174 | if (j == missing[i]) { | |
1175 | ASSERT3U(rows[i][j], ==, 1); | |
1176 | } else { | |
1177 | ASSERT3U(rows[i][j], ==, 0); | |
1178 | } | |
1179 | } | |
1180 | } | |
1181 | } | |
1182 | ||
1183 | static void | |
1184 | vdev_raidz_matrix_reconstruct(raidz_map_t *rm, int n, int nmissing, | |
1185 | int *missing, uint8_t **invrows, const uint8_t *used) | |
1186 | { | |
1187 | int i, j, x, cc, c; | |
1188 | uint8_t *src; | |
1189 | uint64_t ccount; | |
1190 | uint8_t *dst[VDEV_RAIDZ_MAXPARITY]; | |
1191 | uint64_t dcount[VDEV_RAIDZ_MAXPARITY]; | |
1192 | uint8_t log, val; | |
1193 | int ll; | |
1194 | uint8_t *invlog[VDEV_RAIDZ_MAXPARITY]; | |
1195 | uint8_t *p, *pp; | |
1196 | size_t psize; | |
1197 | ||
1198 | psize = sizeof (invlog[0][0]) * n * nmissing; | |
1199 | p = kmem_alloc(psize, KM_SLEEP); | |
1200 | ||
1201 | for (pp = p, i = 0; i < nmissing; i++) { | |
1202 | invlog[i] = pp; | |
1203 | pp += n; | |
1204 | } | |
1205 | ||
1206 | for (i = 0; i < nmissing; i++) { | |
1207 | for (j = 0; j < n; j++) { | |
1208 | ASSERT3U(invrows[i][j], !=, 0); | |
1209 | invlog[i][j] = vdev_raidz_log2[invrows[i][j]]; | |
1210 | } | |
1211 | } | |
1212 | ||
1213 | for (i = 0; i < n; i++) { | |
1214 | c = used[i]; | |
1215 | ASSERT3U(c, <, rm->rm_cols); | |
1216 | ||
1217 | src = rm->rm_col[c].rc_data; | |
1218 | ccount = rm->rm_col[c].rc_size; | |
1219 | for (j = 0; j < nmissing; j++) { | |
1220 | cc = missing[j] + rm->rm_firstdatacol; | |
1221 | ASSERT3U(cc, >=, rm->rm_firstdatacol); | |
1222 | ASSERT3U(cc, <, rm->rm_cols); | |
1223 | ASSERT3U(cc, !=, c); | |
1224 | ||
1225 | dst[j] = rm->rm_col[cc].rc_data; | |
1226 | dcount[j] = rm->rm_col[cc].rc_size; | |
1227 | } | |
1228 | ||
1229 | ASSERT(ccount >= rm->rm_col[missing[0]].rc_size || i > 0); | |
1230 | ||
1231 | for (x = 0; x < ccount; x++, src++) { | |
1232 | if (*src != 0) | |
1233 | log = vdev_raidz_log2[*src]; | |
1234 | ||
1235 | for (cc = 0; cc < nmissing; cc++) { | |
1236 | if (x >= dcount[cc]) | |
1237 | continue; | |
1238 | ||
1239 | if (*src == 0) { | |
1240 | val = 0; | |
1241 | } else { | |
1242 | if ((ll = log + invlog[cc][i]) >= 255) | |
1243 | ll -= 255; | |
1244 | val = vdev_raidz_pow2[ll]; | |
1245 | } | |
1246 | ||
1247 | if (i == 0) | |
1248 | dst[cc][x] = val; | |
1249 | else | |
1250 | dst[cc][x] ^= val; | |
1251 | } | |
1252 | } | |
1253 | } | |
1254 | ||
1255 | kmem_free(p, psize); | |
1256 | } | |
1257 | ||
1258 | static int | |
1259 | vdev_raidz_reconstruct_general(raidz_map_t *rm, int *tgts, int ntgts) | |
1260 | { | |
1261 | int n, i, c, t, tt; | |
1262 | int nmissing_rows; | |
1263 | int missing_rows[VDEV_RAIDZ_MAXPARITY]; | |
1264 | int parity_map[VDEV_RAIDZ_MAXPARITY]; | |
1265 | ||
1266 | uint8_t *p, *pp; | |
1267 | size_t psize; | |
1268 | ||
1269 | uint8_t *rows[VDEV_RAIDZ_MAXPARITY]; | |
1270 | uint8_t *invrows[VDEV_RAIDZ_MAXPARITY]; | |
1271 | uint8_t *used; | |
1272 | ||
1273 | int code = 0; | |
1274 | ||
1275 | ||
1276 | n = rm->rm_cols - rm->rm_firstdatacol; | |
1277 | ||
1278 | /* | |
1279 | * Figure out which data columns are missing. | |
1280 | */ | |
1281 | nmissing_rows = 0; | |
1282 | for (t = 0; t < ntgts; t++) { | |
1283 | if (tgts[t] >= rm->rm_firstdatacol) { | |
1284 | missing_rows[nmissing_rows++] = | |
1285 | tgts[t] - rm->rm_firstdatacol; | |
1286 | } | |
1287 | } | |
1288 | ||
1289 | /* | |
1290 | * Figure out which parity columns to use to help generate the missing | |
1291 | * data columns. | |
1292 | */ | |
1293 | for (tt = 0, c = 0, i = 0; i < nmissing_rows; c++) { | |
1294 | ASSERT(tt < ntgts); | |
1295 | ASSERT(c < rm->rm_firstdatacol); | |
1296 | ||
1297 | /* | |
1298 | * Skip any targeted parity columns. | |
1299 | */ | |
1300 | if (c == tgts[tt]) { | |
1301 | tt++; | |
1302 | continue; | |
1303 | } | |
1304 | ||
1305 | code |= 1 << c; | |
1306 | ||
1307 | parity_map[i] = c; | |
1308 | i++; | |
1309 | } | |
1310 | ||
1311 | ASSERT(code != 0); | |
1312 | ASSERT3U(code, <, 1 << VDEV_RAIDZ_MAXPARITY); | |
1313 | ||
1314 | psize = (sizeof (rows[0][0]) + sizeof (invrows[0][0])) * | |
1315 | nmissing_rows * n + sizeof (used[0]) * n; | |
1316 | p = kmem_alloc(psize, KM_SLEEP); | |
1317 | ||
1318 | for (pp = p, i = 0; i < nmissing_rows; i++) { | |
1319 | rows[i] = pp; | |
1320 | pp += n; | |
1321 | invrows[i] = pp; | |
1322 | pp += n; | |
1323 | } | |
1324 | used = pp; | |
1325 | ||
1326 | for (i = 0; i < nmissing_rows; i++) { | |
1327 | used[i] = parity_map[i]; | |
1328 | } | |
1329 | ||
1330 | for (tt = 0, c = rm->rm_firstdatacol; c < rm->rm_cols; c++) { | |
1331 | if (tt < nmissing_rows && | |
1332 | c == missing_rows[tt] + rm->rm_firstdatacol) { | |
1333 | tt++; | |
1334 | continue; | |
1335 | } | |
1336 | ||
1337 | ASSERT3S(i, <, n); | |
1338 | used[i] = c; | |
1339 | i++; | |
1340 | } | |
1341 | ||
1342 | /* | |
1343 | * Initialize the interesting rows of the matrix. | |
1344 | */ | |
1345 | vdev_raidz_matrix_init(rm, n, nmissing_rows, parity_map, rows); | |
1346 | ||
1347 | /* | |
1348 | * Invert the matrix. | |
1349 | */ | |
1350 | vdev_raidz_matrix_invert(rm, n, nmissing_rows, missing_rows, rows, | |
1351 | invrows, used); | |
1352 | ||
1353 | /* | |
1354 | * Reconstruct the missing data using the generated matrix. | |
1355 | */ | |
1356 | vdev_raidz_matrix_reconstruct(rm, n, nmissing_rows, missing_rows, | |
1357 | invrows, used); | |
1358 | ||
1359 | kmem_free(p, psize); | |
1360 | ||
1361 | return (code); | |
34dc7c2f BB |
1362 | } |
1363 | ||
45d1cae3 BB |
1364 | static int |
1365 | vdev_raidz_reconstruct(raidz_map_t *rm, int *t, int nt) | |
1366 | { | |
1367 | int tgts[VDEV_RAIDZ_MAXPARITY], *dt; | |
1368 | int ntgts; | |
1369 | int i, c; | |
1370 | int code; | |
1371 | int nbadparity, nbaddata; | |
1372 | int parity_valid[VDEV_RAIDZ_MAXPARITY]; | |
1373 | ||
1374 | /* | |
1375 | * The tgts list must already be sorted. | |
1376 | */ | |
1377 | for (i = 1; i < nt; i++) { | |
1378 | ASSERT(t[i] > t[i - 1]); | |
1379 | } | |
1380 | ||
1381 | nbadparity = rm->rm_firstdatacol; | |
1382 | nbaddata = rm->rm_cols - nbadparity; | |
1383 | ntgts = 0; | |
1384 | for (i = 0, c = 0; c < rm->rm_cols; c++) { | |
1385 | if (c < rm->rm_firstdatacol) | |
1386 | parity_valid[c] = B_FALSE; | |
1387 | ||
1388 | if (i < nt && c == t[i]) { | |
1389 | tgts[ntgts++] = c; | |
1390 | i++; | |
1391 | } else if (rm->rm_col[c].rc_error != 0) { | |
1392 | tgts[ntgts++] = c; | |
1393 | } else if (c >= rm->rm_firstdatacol) { | |
1394 | nbaddata--; | |
1395 | } else { | |
1396 | parity_valid[c] = B_TRUE; | |
1397 | nbadparity--; | |
1398 | } | |
1399 | } | |
1400 | ||
1401 | ASSERT(ntgts >= nt); | |
1402 | ASSERT(nbaddata >= 0); | |
1403 | ASSERT(nbaddata + nbadparity == ntgts); | |
1404 | ||
1405 | dt = &tgts[nbadparity]; | |
1406 | ||
1407 | /* | |
1408 | * See if we can use any of our optimized reconstruction routines. | |
1409 | */ | |
1410 | if (!vdev_raidz_default_to_general) { | |
1411 | switch (nbaddata) { | |
1412 | case 1: | |
1413 | if (parity_valid[VDEV_RAIDZ_P]) | |
1414 | return (vdev_raidz_reconstruct_p(rm, dt, 1)); | |
1415 | ||
1416 | ASSERT(rm->rm_firstdatacol > 1); | |
1417 | ||
1418 | if (parity_valid[VDEV_RAIDZ_Q]) | |
1419 | return (vdev_raidz_reconstruct_q(rm, dt, 1)); | |
1420 | ||
1421 | ASSERT(rm->rm_firstdatacol > 2); | |
1422 | break; | |
1423 | ||
1424 | case 2: | |
1425 | ASSERT(rm->rm_firstdatacol > 1); | |
1426 | ||
1427 | if (parity_valid[VDEV_RAIDZ_P] && | |
1428 | parity_valid[VDEV_RAIDZ_Q]) | |
1429 | return (vdev_raidz_reconstruct_pq(rm, dt, 2)); | |
1430 | ||
1431 | ASSERT(rm->rm_firstdatacol > 2); | |
1432 | ||
1433 | break; | |
1434 | } | |
1435 | } | |
1436 | ||
1437 | code = vdev_raidz_reconstruct_general(rm, tgts, ntgts); | |
1438 | ASSERT(code < (1 << VDEV_RAIDZ_MAXPARITY)); | |
1439 | ASSERT(code > 0); | |
1440 | return (code); | |
1441 | } | |
34dc7c2f BB |
1442 | |
1443 | static int | |
1444 | vdev_raidz_open(vdev_t *vd, uint64_t *asize, uint64_t *ashift) | |
1445 | { | |
1446 | vdev_t *cvd; | |
1447 | uint64_t nparity = vd->vdev_nparity; | |
45d1cae3 | 1448 | int c; |
34dc7c2f BB |
1449 | int lasterror = 0; |
1450 | int numerrors = 0; | |
1451 | ||
1452 | ASSERT(nparity > 0); | |
1453 | ||
1454 | if (nparity > VDEV_RAIDZ_MAXPARITY || | |
1455 | vd->vdev_children < nparity + 1) { | |
1456 | vd->vdev_stat.vs_aux = VDEV_AUX_BAD_LABEL; | |
1457 | return (EINVAL); | |
1458 | } | |
1459 | ||
45d1cae3 BB |
1460 | vdev_open_children(vd); |
1461 | ||
34dc7c2f BB |
1462 | for (c = 0; c < vd->vdev_children; c++) { |
1463 | cvd = vd->vdev_child[c]; | |
1464 | ||
45d1cae3 BB |
1465 | if (cvd->vdev_open_error != 0) { |
1466 | lasterror = cvd->vdev_open_error; | |
34dc7c2f BB |
1467 | numerrors++; |
1468 | continue; | |
1469 | } | |
1470 | ||
1471 | *asize = MIN(*asize - 1, cvd->vdev_asize - 1) + 1; | |
1472 | *ashift = MAX(*ashift, cvd->vdev_ashift); | |
1473 | } | |
1474 | ||
1475 | *asize *= vd->vdev_children; | |
1476 | ||
1477 | if (numerrors > nparity) { | |
1478 | vd->vdev_stat.vs_aux = VDEV_AUX_NO_REPLICAS; | |
1479 | return (lasterror); | |
1480 | } | |
1481 | ||
1482 | return (0); | |
1483 | } | |
1484 | ||
1485 | static void | |
1486 | vdev_raidz_close(vdev_t *vd) | |
1487 | { | |
1488 | int c; | |
1489 | ||
1490 | for (c = 0; c < vd->vdev_children; c++) | |
1491 | vdev_close(vd->vdev_child[c]); | |
1492 | } | |
1493 | ||
1494 | static uint64_t | |
1495 | vdev_raidz_asize(vdev_t *vd, uint64_t psize) | |
1496 | { | |
1497 | uint64_t asize; | |
1498 | uint64_t ashift = vd->vdev_top->vdev_ashift; | |
1499 | uint64_t cols = vd->vdev_children; | |
1500 | uint64_t nparity = vd->vdev_nparity; | |
1501 | ||
1502 | asize = ((psize - 1) >> ashift) + 1; | |
1503 | asize += nparity * ((asize + cols - nparity - 1) / (cols - nparity)); | |
1504 | asize = roundup(asize, nparity + 1) << ashift; | |
1505 | ||
1506 | return (asize); | |
1507 | } | |
1508 | ||
1509 | static void | |
1510 | vdev_raidz_child_done(zio_t *zio) | |
1511 | { | |
1512 | raidz_col_t *rc = zio->io_private; | |
1513 | ||
1514 | rc->rc_error = zio->io_error; | |
1515 | rc->rc_tried = 1; | |
1516 | rc->rc_skipped = 0; | |
1517 | } | |
1518 | ||
34dc7c2f BB |
1519 | static int |
1520 | vdev_raidz_io_start(zio_t *zio) | |
1521 | { | |
1522 | vdev_t *vd = zio->io_vd; | |
1523 | vdev_t *tvd = vd->vdev_top; | |
1524 | vdev_t *cvd; | |
34dc7c2f BB |
1525 | raidz_map_t *rm; |
1526 | raidz_col_t *rc; | |
45d1cae3 | 1527 | int c, i; |
34dc7c2f BB |
1528 | |
1529 | rm = vdev_raidz_map_alloc(zio, tvd->vdev_ashift, vd->vdev_children, | |
1530 | vd->vdev_nparity); | |
1531 | ||
1532 | ASSERT3U(rm->rm_asize, ==, vdev_psize_to_asize(vd, zio->io_size)); | |
1533 | ||
1534 | if (zio->io_type == ZIO_TYPE_WRITE) { | |
45d1cae3 | 1535 | vdev_raidz_generate_parity(rm); |
34dc7c2f BB |
1536 | |
1537 | for (c = 0; c < rm->rm_cols; c++) { | |
1538 | rc = &rm->rm_col[c]; | |
1539 | cvd = vd->vdev_child[rc->rc_devidx]; | |
1540 | zio_nowait(zio_vdev_child_io(zio, NULL, cvd, | |
1541 | rc->rc_offset, rc->rc_data, rc->rc_size, | |
b128c09f | 1542 | zio->io_type, zio->io_priority, 0, |
34dc7c2f BB |
1543 | vdev_raidz_child_done, rc)); |
1544 | } | |
1545 | ||
45d1cae3 BB |
1546 | /* |
1547 | * Generate optional I/Os for any skipped sectors to improve | |
1548 | * aggregation contiguity. | |
1549 | */ | |
428870ff | 1550 | for (c = rm->rm_skipstart, i = 0; i < rm->rm_nskip; c++, i++) { |
45d1cae3 BB |
1551 | ASSERT(c <= rm->rm_scols); |
1552 | if (c == rm->rm_scols) | |
1553 | c = 0; | |
1554 | rc = &rm->rm_col[c]; | |
1555 | cvd = vd->vdev_child[rc->rc_devidx]; | |
1556 | zio_nowait(zio_vdev_child_io(zio, NULL, cvd, | |
1557 | rc->rc_offset + rc->rc_size, NULL, | |
1558 | 1 << tvd->vdev_ashift, | |
1559 | zio->io_type, zio->io_priority, | |
1560 | ZIO_FLAG_NODATA | ZIO_FLAG_OPTIONAL, NULL, NULL)); | |
1561 | } | |
1562 | ||
b128c09f | 1563 | return (ZIO_PIPELINE_CONTINUE); |
34dc7c2f BB |
1564 | } |
1565 | ||
1566 | ASSERT(zio->io_type == ZIO_TYPE_READ); | |
1567 | ||
1568 | /* | |
1569 | * Iterate over the columns in reverse order so that we hit the parity | |
45d1cae3 | 1570 | * last -- any errors along the way will force us to read the parity. |
34dc7c2f BB |
1571 | */ |
1572 | for (c = rm->rm_cols - 1; c >= 0; c--) { | |
1573 | rc = &rm->rm_col[c]; | |
1574 | cvd = vd->vdev_child[rc->rc_devidx]; | |
1575 | if (!vdev_readable(cvd)) { | |
1576 | if (c >= rm->rm_firstdatacol) | |
1577 | rm->rm_missingdata++; | |
1578 | else | |
1579 | rm->rm_missingparity++; | |
1580 | rc->rc_error = ENXIO; | |
1581 | rc->rc_tried = 1; /* don't even try */ | |
1582 | rc->rc_skipped = 1; | |
1583 | continue; | |
1584 | } | |
428870ff | 1585 | if (vdev_dtl_contains(cvd, DTL_MISSING, zio->io_txg, 1)) { |
34dc7c2f BB |
1586 | if (c >= rm->rm_firstdatacol) |
1587 | rm->rm_missingdata++; | |
1588 | else | |
1589 | rm->rm_missingparity++; | |
1590 | rc->rc_error = ESTALE; | |
1591 | rc->rc_skipped = 1; | |
1592 | continue; | |
1593 | } | |
1594 | if (c >= rm->rm_firstdatacol || rm->rm_missingdata > 0 || | |
9babb374 | 1595 | (zio->io_flags & (ZIO_FLAG_SCRUB | ZIO_FLAG_RESILVER))) { |
34dc7c2f BB |
1596 | zio_nowait(zio_vdev_child_io(zio, NULL, cvd, |
1597 | rc->rc_offset, rc->rc_data, rc->rc_size, | |
b128c09f | 1598 | zio->io_type, zio->io_priority, 0, |
34dc7c2f BB |
1599 | vdev_raidz_child_done, rc)); |
1600 | } | |
1601 | } | |
1602 | ||
b128c09f | 1603 | return (ZIO_PIPELINE_CONTINUE); |
34dc7c2f BB |
1604 | } |
1605 | ||
428870ff | 1606 | |
34dc7c2f BB |
1607 | /* |
1608 | * Report a checksum error for a child of a RAID-Z device. | |
1609 | */ | |
1610 | static void | |
428870ff | 1611 | raidz_checksum_error(zio_t *zio, raidz_col_t *rc, void *bad_data) |
34dc7c2f BB |
1612 | { |
1613 | vdev_t *vd = zio->io_vd->vdev_child[rc->rc_devidx]; | |
34dc7c2f BB |
1614 | |
1615 | if (!(zio->io_flags & ZIO_FLAG_SPECULATIVE)) { | |
428870ff BB |
1616 | zio_bad_cksum_t zbc; |
1617 | raidz_map_t *rm = zio->io_vsd; | |
1618 | ||
34dc7c2f BB |
1619 | mutex_enter(&vd->vdev_stat_lock); |
1620 | vd->vdev_stat.vs_checksum_errors++; | |
1621 | mutex_exit(&vd->vdev_stat_lock); | |
428870ff BB |
1622 | |
1623 | zbc.zbc_has_cksum = 0; | |
1624 | zbc.zbc_injected = rm->rm_ecksuminjected; | |
1625 | ||
1626 | zfs_ereport_post_checksum(zio->io_spa, vd, zio, | |
1627 | rc->rc_offset, rc->rc_size, rc->rc_data, bad_data, | |
1628 | &zbc); | |
34dc7c2f | 1629 | } |
428870ff BB |
1630 | } |
1631 | ||
1632 | /* | |
1633 | * We keep track of whether or not there were any injected errors, so that | |
1634 | * any ereports we generate can note it. | |
1635 | */ | |
1636 | static int | |
1637 | raidz_checksum_verify(zio_t *zio) | |
1638 | { | |
1639 | zio_bad_cksum_t zbc; | |
1640 | raidz_map_t *rm = zio->io_vsd; | |
1641 | ||
1642 | int ret = zio_checksum_error(zio, &zbc); | |
1643 | if (ret != 0 && zbc.zbc_injected != 0) | |
1644 | rm->rm_ecksuminjected = 1; | |
34dc7c2f | 1645 | |
428870ff | 1646 | return (ret); |
34dc7c2f BB |
1647 | } |
1648 | ||
1649 | /* | |
1650 | * Generate the parity from the data columns. If we tried and were able to | |
1651 | * read the parity without error, verify that the generated parity matches the | |
1652 | * data we read. If it doesn't, we fire off a checksum error. Return the | |
1653 | * number such failures. | |
1654 | */ | |
1655 | static int | |
1656 | raidz_parity_verify(zio_t *zio, raidz_map_t *rm) | |
1657 | { | |
1658 | void *orig[VDEV_RAIDZ_MAXPARITY]; | |
1659 | int c, ret = 0; | |
1660 | raidz_col_t *rc; | |
1661 | ||
1662 | for (c = 0; c < rm->rm_firstdatacol; c++) { | |
1663 | rc = &rm->rm_col[c]; | |
1664 | if (!rc->rc_tried || rc->rc_error != 0) | |
1665 | continue; | |
1666 | orig[c] = zio_buf_alloc(rc->rc_size); | |
1667 | bcopy(rc->rc_data, orig[c], rc->rc_size); | |
1668 | } | |
1669 | ||
45d1cae3 | 1670 | vdev_raidz_generate_parity(rm); |
34dc7c2f BB |
1671 | |
1672 | for (c = 0; c < rm->rm_firstdatacol; c++) { | |
1673 | rc = &rm->rm_col[c]; | |
1674 | if (!rc->rc_tried || rc->rc_error != 0) | |
1675 | continue; | |
1676 | if (bcmp(orig[c], rc->rc_data, rc->rc_size) != 0) { | |
428870ff | 1677 | raidz_checksum_error(zio, rc, orig[c]); |
34dc7c2f BB |
1678 | rc->rc_error = ECKSUM; |
1679 | ret++; | |
1680 | } | |
1681 | zio_buf_free(orig[c], rc->rc_size); | |
1682 | } | |
1683 | ||
1684 | return (ret); | |
1685 | } | |
1686 | ||
45d1cae3 BB |
1687 | /* |
1688 | * Keep statistics on all the ways that we used parity to correct data. | |
1689 | */ | |
1690 | static uint64_t raidz_corrected[1 << VDEV_RAIDZ_MAXPARITY]; | |
34dc7c2f BB |
1691 | |
1692 | static int | |
b128c09f BB |
1693 | vdev_raidz_worst_error(raidz_map_t *rm) |
1694 | { | |
d6320ddb | 1695 | int c, error = 0; |
b128c09f | 1696 | |
d6320ddb | 1697 | for (c = 0; c < rm->rm_cols; c++) |
b128c09f BB |
1698 | error = zio_worst_error(error, rm->rm_col[c].rc_error); |
1699 | ||
1700 | return (error); | |
1701 | } | |
1702 | ||
45d1cae3 BB |
1703 | /* |
1704 | * Iterate over all combinations of bad data and attempt a reconstruction. | |
1705 | * Note that the algorithm below is non-optimal because it doesn't take into | |
1706 | * account how reconstruction is actually performed. For example, with | |
1707 | * triple-parity RAID-Z the reconstruction procedure is the same if column 4 | |
1708 | * is targeted as invalid as if columns 1 and 4 are targeted since in both | |
1709 | * cases we'd only use parity information in column 0. | |
1710 | */ | |
1711 | static int | |
1712 | vdev_raidz_combrec(zio_t *zio, int total_errors, int data_errors) | |
1713 | { | |
1714 | raidz_map_t *rm = zio->io_vsd; | |
1715 | raidz_col_t *rc; | |
1716 | void *orig[VDEV_RAIDZ_MAXPARITY]; | |
1717 | int tstore[VDEV_RAIDZ_MAXPARITY + 2]; | |
1718 | int *tgts = &tstore[1]; | |
1719 | int current, next, i, c, n; | |
1720 | int code, ret = 0; | |
1721 | ||
1722 | ASSERT(total_errors < rm->rm_firstdatacol); | |
1723 | ||
1724 | /* | |
1725 | * This simplifies one edge condition. | |
1726 | */ | |
1727 | tgts[-1] = -1; | |
1728 | ||
1729 | for (n = 1; n <= rm->rm_firstdatacol - total_errors; n++) { | |
1730 | /* | |
1731 | * Initialize the targets array by finding the first n columns | |
1732 | * that contain no error. | |
1733 | * | |
1734 | * If there were no data errors, we need to ensure that we're | |
1735 | * always explicitly attempting to reconstruct at least one | |
1736 | * data column. To do this, we simply push the highest target | |
1737 | * up into the data columns. | |
1738 | */ | |
1739 | for (c = 0, i = 0; i < n; i++) { | |
1740 | if (i == n - 1 && data_errors == 0 && | |
1741 | c < rm->rm_firstdatacol) { | |
1742 | c = rm->rm_firstdatacol; | |
1743 | } | |
1744 | ||
1745 | while (rm->rm_col[c].rc_error != 0) { | |
1746 | c++; | |
1747 | ASSERT3S(c, <, rm->rm_cols); | |
1748 | } | |
1749 | ||
1750 | tgts[i] = c++; | |
1751 | } | |
1752 | ||
1753 | /* | |
1754 | * Setting tgts[n] simplifies the other edge condition. | |
1755 | */ | |
1756 | tgts[n] = rm->rm_cols; | |
1757 | ||
1758 | /* | |
1759 | * These buffers were allocated in previous iterations. | |
1760 | */ | |
1761 | for (i = 0; i < n - 1; i++) { | |
1762 | ASSERT(orig[i] != NULL); | |
1763 | } | |
1764 | ||
1765 | orig[n - 1] = zio_buf_alloc(rm->rm_col[0].rc_size); | |
1766 | ||
1767 | current = 0; | |
1768 | next = tgts[current]; | |
1769 | ||
1770 | while (current != n) { | |
1771 | tgts[current] = next; | |
1772 | current = 0; | |
1773 | ||
1774 | /* | |
1775 | * Save off the original data that we're going to | |
1776 | * attempt to reconstruct. | |
1777 | */ | |
1778 | for (i = 0; i < n; i++) { | |
1779 | ASSERT(orig[i] != NULL); | |
1780 | c = tgts[i]; | |
1781 | ASSERT3S(c, >=, 0); | |
1782 | ASSERT3S(c, <, rm->rm_cols); | |
1783 | rc = &rm->rm_col[c]; | |
1784 | bcopy(rc->rc_data, orig[i], rc->rc_size); | |
1785 | } | |
1786 | ||
1787 | /* | |
1788 | * Attempt a reconstruction and exit the outer loop on | |
1789 | * success. | |
1790 | */ | |
1791 | code = vdev_raidz_reconstruct(rm, tgts, n); | |
428870ff | 1792 | if (raidz_checksum_verify(zio) == 0) { |
45d1cae3 BB |
1793 | atomic_inc_64(&raidz_corrected[code]); |
1794 | ||
1795 | for (i = 0; i < n; i++) { | |
1796 | c = tgts[i]; | |
1797 | rc = &rm->rm_col[c]; | |
1798 | ASSERT(rc->rc_error == 0); | |
1799 | if (rc->rc_tried) | |
428870ff BB |
1800 | raidz_checksum_error(zio, rc, |
1801 | orig[i]); | |
45d1cae3 BB |
1802 | rc->rc_error = ECKSUM; |
1803 | } | |
1804 | ||
1805 | ret = code; | |
1806 | goto done; | |
1807 | } | |
1808 | ||
1809 | /* | |
1810 | * Restore the original data. | |
1811 | */ | |
1812 | for (i = 0; i < n; i++) { | |
1813 | c = tgts[i]; | |
1814 | rc = &rm->rm_col[c]; | |
1815 | bcopy(orig[i], rc->rc_data, rc->rc_size); | |
1816 | } | |
1817 | ||
1818 | do { | |
1819 | /* | |
1820 | * Find the next valid column after the current | |
1821 | * position.. | |
1822 | */ | |
1823 | for (next = tgts[current] + 1; | |
1824 | next < rm->rm_cols && | |
1825 | rm->rm_col[next].rc_error != 0; next++) | |
1826 | continue; | |
1827 | ||
1828 | ASSERT(next <= tgts[current + 1]); | |
1829 | ||
1830 | /* | |
1831 | * If that spot is available, we're done here. | |
1832 | */ | |
1833 | if (next != tgts[current + 1]) | |
1834 | break; | |
1835 | ||
1836 | /* | |
1837 | * Otherwise, find the next valid column after | |
1838 | * the previous position. | |
1839 | */ | |
1840 | for (c = tgts[current - 1] + 1; | |
1841 | rm->rm_col[c].rc_error != 0; c++) | |
1842 | continue; | |
1843 | ||
1844 | tgts[current] = c; | |
1845 | current++; | |
1846 | ||
1847 | } while (current != n); | |
1848 | } | |
1849 | } | |
1850 | n--; | |
1851 | done: | |
1852 | for (i = 0; i < n; i++) { | |
1853 | zio_buf_free(orig[i], rm->rm_col[0].rc_size); | |
1854 | } | |
1855 | ||
1856 | return (ret); | |
1857 | } | |
1858 | ||
b128c09f | 1859 | static void |
34dc7c2f BB |
1860 | vdev_raidz_io_done(zio_t *zio) |
1861 | { | |
1862 | vdev_t *vd = zio->io_vd; | |
1863 | vdev_t *cvd; | |
1864 | raidz_map_t *rm = zio->io_vsd; | |
45d1cae3 | 1865 | raidz_col_t *rc; |
34dc7c2f BB |
1866 | int unexpected_errors = 0; |
1867 | int parity_errors = 0; | |
1868 | int parity_untried = 0; | |
1869 | int data_errors = 0; | |
b128c09f | 1870 | int total_errors = 0; |
45d1cae3 BB |
1871 | int n, c; |
1872 | int tgts[VDEV_RAIDZ_MAXPARITY]; | |
1873 | int code; | |
34dc7c2f BB |
1874 | |
1875 | ASSERT(zio->io_bp != NULL); /* XXX need to add code to enforce this */ | |
1876 | ||
34dc7c2f BB |
1877 | ASSERT(rm->rm_missingparity <= rm->rm_firstdatacol); |
1878 | ASSERT(rm->rm_missingdata <= rm->rm_cols - rm->rm_firstdatacol); | |
1879 | ||
1880 | for (c = 0; c < rm->rm_cols; c++) { | |
1881 | rc = &rm->rm_col[c]; | |
1882 | ||
34dc7c2f | 1883 | if (rc->rc_error) { |
b128c09f | 1884 | ASSERT(rc->rc_error != ECKSUM); /* child has no bp */ |
34dc7c2f BB |
1885 | |
1886 | if (c < rm->rm_firstdatacol) | |
1887 | parity_errors++; | |
1888 | else | |
1889 | data_errors++; | |
1890 | ||
1891 | if (!rc->rc_skipped) | |
1892 | unexpected_errors++; | |
1893 | ||
b128c09f | 1894 | total_errors++; |
34dc7c2f BB |
1895 | } else if (c < rm->rm_firstdatacol && !rc->rc_tried) { |
1896 | parity_untried++; | |
1897 | } | |
1898 | } | |
1899 | ||
1900 | if (zio->io_type == ZIO_TYPE_WRITE) { | |
1901 | /* | |
b128c09f BB |
1902 | * XXX -- for now, treat partial writes as a success. |
1903 | * (If we couldn't write enough columns to reconstruct | |
1904 | * the data, the I/O failed. Otherwise, good enough.) | |
1905 | * | |
1906 | * Now that we support write reallocation, it would be better | |
1907 | * to treat partial failure as real failure unless there are | |
1908 | * no non-degraded top-level vdevs left, and not update DTLs | |
1909 | * if we intend to reallocate. | |
34dc7c2f BB |
1910 | */ |
1911 | /* XXPOLICY */ | |
b128c09f BB |
1912 | if (total_errors > rm->rm_firstdatacol) |
1913 | zio->io_error = vdev_raidz_worst_error(rm); | |
34dc7c2f | 1914 | |
b128c09f | 1915 | return; |
34dc7c2f BB |
1916 | } |
1917 | ||
1918 | ASSERT(zio->io_type == ZIO_TYPE_READ); | |
1919 | /* | |
1920 | * There are three potential phases for a read: | |
1921 | * 1. produce valid data from the columns read | |
1922 | * 2. read all disks and try again | |
1923 | * 3. perform combinatorial reconstruction | |
1924 | * | |
1925 | * Each phase is progressively both more expensive and less likely to | |
1926 | * occur. If we encounter more errors than we can repair or all phases | |
1927 | * fail, we have no choice but to return an error. | |
1928 | */ | |
1929 | ||
1930 | /* | |
1931 | * If the number of errors we saw was correctable -- less than or equal | |
1932 | * to the number of parity disks read -- attempt to produce data that | |
1933 | * has a valid checksum. Naturally, this case applies in the absence of | |
1934 | * any errors. | |
1935 | */ | |
b128c09f | 1936 | if (total_errors <= rm->rm_firstdatacol - parity_untried) { |
45d1cae3 | 1937 | if (data_errors == 0) { |
428870ff | 1938 | if (raidz_checksum_verify(zio) == 0) { |
34dc7c2f BB |
1939 | /* |
1940 | * If we read parity information (unnecessarily | |
1941 | * as it happens since no reconstruction was | |
1942 | * needed) regenerate and verify the parity. | |
1943 | * We also regenerate parity when resilvering | |
1944 | * so we can write it out to the failed device | |
1945 | * later. | |
1946 | */ | |
1947 | if (parity_errors + parity_untried < | |
1948 | rm->rm_firstdatacol || | |
1949 | (zio->io_flags & ZIO_FLAG_RESILVER)) { | |
1950 | n = raidz_parity_verify(zio, rm); | |
1951 | unexpected_errors += n; | |
1952 | ASSERT(parity_errors + n <= | |
1953 | rm->rm_firstdatacol); | |
1954 | } | |
1955 | goto done; | |
1956 | } | |
45d1cae3 | 1957 | } else { |
34dc7c2f BB |
1958 | /* |
1959 | * We either attempt to read all the parity columns or | |
1960 | * none of them. If we didn't try to read parity, we | |
1961 | * wouldn't be here in the correctable case. There must | |
1962 | * also have been fewer parity errors than parity | |
1963 | * columns or, again, we wouldn't be in this code path. | |
1964 | */ | |
1965 | ASSERT(parity_untried == 0); | |
1966 | ASSERT(parity_errors < rm->rm_firstdatacol); | |
1967 | ||
1968 | /* | |
45d1cae3 | 1969 | * Identify the data columns that reported an error. |
34dc7c2f | 1970 | */ |
45d1cae3 | 1971 | n = 0; |
34dc7c2f BB |
1972 | for (c = rm->rm_firstdatacol; c < rm->rm_cols; c++) { |
1973 | rc = &rm->rm_col[c]; | |
45d1cae3 BB |
1974 | if (rc->rc_error != 0) { |
1975 | ASSERT(n < VDEV_RAIDZ_MAXPARITY); | |
1976 | tgts[n++] = c; | |
1977 | } | |
34dc7c2f | 1978 | } |
34dc7c2f | 1979 | |
45d1cae3 BB |
1980 | ASSERT(rm->rm_firstdatacol >= n); |
1981 | ||
1982 | code = vdev_raidz_reconstruct(rm, tgts, n); | |
34dc7c2f | 1983 | |
428870ff | 1984 | if (raidz_checksum_verify(zio) == 0) { |
45d1cae3 | 1985 | atomic_inc_64(&raidz_corrected[code]); |
34dc7c2f BB |
1986 | |
1987 | /* | |
45d1cae3 BB |
1988 | * If we read more parity disks than were used |
1989 | * for reconstruction, confirm that the other | |
1990 | * parity disks produced correct data. This | |
1991 | * routine is suboptimal in that it regenerates | |
1992 | * the parity that we already used in addition | |
1993 | * to the parity that we're attempting to | |
1994 | * verify, but this should be a relatively | |
1995 | * uncommon case, and can be optimized if it | |
1996 | * becomes a problem. Note that we regenerate | |
1997 | * parity when resilvering so we can write it | |
1998 | * out to failed devices later. | |
34dc7c2f | 1999 | */ |
45d1cae3 | 2000 | if (parity_errors < rm->rm_firstdatacol - n || |
34dc7c2f BB |
2001 | (zio->io_flags & ZIO_FLAG_RESILVER)) { |
2002 | n = raidz_parity_verify(zio, rm); | |
2003 | unexpected_errors += n; | |
2004 | ASSERT(parity_errors + n <= | |
2005 | rm->rm_firstdatacol); | |
2006 | } | |
2007 | ||
2008 | goto done; | |
2009 | } | |
34dc7c2f BB |
2010 | } |
2011 | } | |
2012 | ||
2013 | /* | |
2014 | * This isn't a typical situation -- either we got a read error or | |
2015 | * a child silently returned bad data. Read every block so we can | |
2016 | * try again with as much data and parity as we can track down. If | |
2017 | * we've already been through once before, all children will be marked | |
2018 | * as tried so we'll proceed to combinatorial reconstruction. | |
2019 | */ | |
2020 | unexpected_errors = 1; | |
2021 | rm->rm_missingdata = 0; | |
2022 | rm->rm_missingparity = 0; | |
2023 | ||
2024 | for (c = 0; c < rm->rm_cols; c++) { | |
2025 | if (rm->rm_col[c].rc_tried) | |
2026 | continue; | |
2027 | ||
34dc7c2f BB |
2028 | zio_vdev_io_redone(zio); |
2029 | do { | |
2030 | rc = &rm->rm_col[c]; | |
2031 | if (rc->rc_tried) | |
2032 | continue; | |
2033 | zio_nowait(zio_vdev_child_io(zio, NULL, | |
2034 | vd->vdev_child[rc->rc_devidx], | |
2035 | rc->rc_offset, rc->rc_data, rc->rc_size, | |
b128c09f | 2036 | zio->io_type, zio->io_priority, 0, |
34dc7c2f BB |
2037 | vdev_raidz_child_done, rc)); |
2038 | } while (++c < rm->rm_cols); | |
34dc7c2f | 2039 | |
b128c09f | 2040 | return; |
34dc7c2f BB |
2041 | } |
2042 | ||
2043 | /* | |
2044 | * At this point we've attempted to reconstruct the data given the | |
2045 | * errors we detected, and we've attempted to read all columns. There | |
2046 | * must, therefore, be one or more additional problems -- silent errors | |
2047 | * resulting in invalid data rather than explicit I/O errors resulting | |
45d1cae3 BB |
2048 | * in absent data. We check if there is enough additional data to |
2049 | * possibly reconstruct the data and then perform combinatorial | |
2050 | * reconstruction over all possible combinations. If that fails, | |
2051 | * we're cooked. | |
34dc7c2f | 2052 | */ |
428870ff | 2053 | if (total_errors > rm->rm_firstdatacol) { |
b128c09f | 2054 | zio->io_error = vdev_raidz_worst_error(rm); |
34dc7c2f | 2055 | |
428870ff BB |
2056 | } else if (total_errors < rm->rm_firstdatacol && |
2057 | (code = vdev_raidz_combrec(zio, total_errors, data_errors)) != 0) { | |
34dc7c2f | 2058 | /* |
45d1cae3 BB |
2059 | * If we didn't use all the available parity for the |
2060 | * combinatorial reconstruction, verify that the remaining | |
2061 | * parity is correct. | |
34dc7c2f | 2062 | */ |
45d1cae3 BB |
2063 | if (code != (1 << rm->rm_firstdatacol) - 1) |
2064 | (void) raidz_parity_verify(zio, rm); | |
2065 | } else { | |
34dc7c2f | 2066 | /* |
428870ff BB |
2067 | * We're here because either: |
2068 | * | |
2069 | * total_errors == rm_first_datacol, or | |
2070 | * vdev_raidz_combrec() failed | |
2071 | * | |
2072 | * In either case, there is enough bad data to prevent | |
2073 | * reconstruction. | |
2074 | * | |
2075 | * Start checksum ereports for all children which haven't | |
2076 | * failed, and the IO wasn't speculative. | |
34dc7c2f | 2077 | */ |
45d1cae3 | 2078 | zio->io_error = ECKSUM; |
34dc7c2f | 2079 | |
45d1cae3 BB |
2080 | if (!(zio->io_flags & ZIO_FLAG_SPECULATIVE)) { |
2081 | for (c = 0; c < rm->rm_cols; c++) { | |
2082 | rc = &rm->rm_col[c]; | |
428870ff BB |
2083 | if (rc->rc_error == 0) { |
2084 | zio_bad_cksum_t zbc; | |
2085 | zbc.zbc_has_cksum = 0; | |
2086 | zbc.zbc_injected = | |
2087 | rm->rm_ecksuminjected; | |
2088 | ||
2089 | zfs_ereport_start_checksum( | |
2090 | zio->io_spa, | |
2091 | vd->vdev_child[rc->rc_devidx], | |
2092 | zio, rc->rc_offset, rc->rc_size, | |
2093 | (void *)(uintptr_t)c, &zbc); | |
2094 | } | |
34dc7c2f | 2095 | } |
34dc7c2f BB |
2096 | } |
2097 | } | |
2098 | ||
2099 | done: | |
2100 | zio_checksum_verified(zio); | |
2101 | ||
fb5f0bc8 | 2102 | if (zio->io_error == 0 && spa_writeable(zio->io_spa) && |
34dc7c2f | 2103 | (unexpected_errors || (zio->io_flags & ZIO_FLAG_RESILVER))) { |
34dc7c2f BB |
2104 | /* |
2105 | * Use the good data we have in hand to repair damaged children. | |
34dc7c2f | 2106 | */ |
34dc7c2f BB |
2107 | for (c = 0; c < rm->rm_cols; c++) { |
2108 | rc = &rm->rm_col[c]; | |
2109 | cvd = vd->vdev_child[rc->rc_devidx]; | |
2110 | ||
2111 | if (rc->rc_error == 0) | |
2112 | continue; | |
2113 | ||
b128c09f | 2114 | zio_nowait(zio_vdev_child_io(zio, NULL, cvd, |
34dc7c2f BB |
2115 | rc->rc_offset, rc->rc_data, rc->rc_size, |
2116 | ZIO_TYPE_WRITE, zio->io_priority, | |
fb5f0bc8 BB |
2117 | ZIO_FLAG_IO_REPAIR | (unexpected_errors ? |
2118 | ZIO_FLAG_SELF_HEAL : 0), NULL, NULL)); | |
34dc7c2f | 2119 | } |
34dc7c2f | 2120 | } |
34dc7c2f BB |
2121 | } |
2122 | ||
2123 | static void | |
2124 | vdev_raidz_state_change(vdev_t *vd, int faulted, int degraded) | |
2125 | { | |
2126 | if (faulted > vd->vdev_nparity) | |
2127 | vdev_set_state(vd, B_FALSE, VDEV_STATE_CANT_OPEN, | |
2128 | VDEV_AUX_NO_REPLICAS); | |
2129 | else if (degraded + faulted != 0) | |
2130 | vdev_set_state(vd, B_FALSE, VDEV_STATE_DEGRADED, VDEV_AUX_NONE); | |
2131 | else | |
2132 | vdev_set_state(vd, B_FALSE, VDEV_STATE_HEALTHY, VDEV_AUX_NONE); | |
2133 | } | |
2134 | ||
2135 | vdev_ops_t vdev_raidz_ops = { | |
2136 | vdev_raidz_open, | |
2137 | vdev_raidz_close, | |
34dc7c2f BB |
2138 | vdev_raidz_asize, |
2139 | vdev_raidz_io_start, | |
2140 | vdev_raidz_io_done, | |
2141 | vdev_raidz_state_change, | |
428870ff BB |
2142 | NULL, |
2143 | NULL, | |
34dc7c2f BB |
2144 | VDEV_TYPE_RAIDZ, /* name of this vdev type */ |
2145 | B_FALSE /* not a leaf vdev */ | |
2146 | }; |