1 /* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License (the "License"). 6 * You may not use this file except in compliance with the License. 7 * 8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 9 * or http://www.opensolaris.org/os/licensing. 10 * See the License for the specific language governing permissions 11 * and limitations under the License. 12 * 13 * When distributing Covered Code, include this CDDL HEADER in each 14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 15 * If applicable, add the following below this CDDL HEADER, with the 16 * fields enclosed by brackets "[]" replaced with your own identifying 17 * information: Portions Copyright [yyyy] [name of copyright owner] 18 * 19 * CDDL HEADER END 20 */ 21 /* 22 * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved. 23 * Copyright (c) 2013 by Delphix. All rights reserved. 24 * Copyright (c) 2013, Joyent, Inc. All rights reserved. 25 */ 26 27 #include <sys/zfs_context.h> 28 #include <sys/spa.h> 29 #include <sys/zio.h> 30 #include <sys/zio_checksum.h> 31 #include <sys/zil.h> 32 #include <zfs_fletcher.h> 33 34 /* 35 * Checksum vectors. 36 * 37 * In the SPA, everything is checksummed. We support checksum vectors 38 * for three distinct reasons: 39 * 40 * 1. Different kinds of data need different levels of protection. 41 * For SPA metadata, we always want a very strong checksum. 42 * For user data, we let users make the trade-off between speed 43 * and checksum strength. 44 * 45 * 2. Cryptographic hash and MAC algorithms are an area of active research. 46 * It is likely that in future hash functions will be at least as strong 47 * as current best-of-breed, and may be substantially faster as well. 48 * We want the ability to take advantage of these new hashes as soon as 49 * they become available. 50 * 51 * 3. If someone develops hardware that can compute a strong hash quickly, 52 * we want the ability to take advantage of that hardware. 53 * 54 * Of course, we don't want a checksum upgrade to invalidate existing 55 * data, so we store the checksum *function* in eight bits of the bp. 56 * This gives us room for up to 256 different checksum functions. 57 * 58 * When writing a block, we always checksum it with the latest-and-greatest 59 * checksum function of the appropriate strength. When reading a block, 60 * we compare the expected checksum against the actual checksum, which we 61 * compute via the checksum function specified by BP_GET_CHECKSUM(bp). 62 */ 63 64 /*ARGSUSED*/ 65 static void 66 zio_checksum_off(const void *buf, uint64_t size, zio_cksum_t *zcp) 67 { 68 ZIO_SET_CHECKSUM(zcp, 0, 0, 0, 0); 69 } 70 71 zio_checksum_info_t zio_checksum_table[ZIO_CHECKSUM_FUNCTIONS] = { 72 {{NULL, NULL}, 0, 0, 0, "inherit"}, 73 {{NULL, NULL}, 0, 0, 0, "on"}, 74 {{zio_checksum_off, zio_checksum_off}, 0, 0, 0, "off"}, 75 {{zio_checksum_SHA256, zio_checksum_SHA256}, 1, 1, 0, "label"}, 76 {{zio_checksum_SHA256, zio_checksum_SHA256}, 1, 1, 0, "gang_header"}, 77 {{fletcher_2_native, fletcher_2_byteswap}, 0, 1, 0, "zilog"}, 78 {{fletcher_2_native, fletcher_2_byteswap}, 0, 0, 0, "fletcher2"}, 79 {{fletcher_4_native, fletcher_4_byteswap}, 1, 0, 0, "fletcher4"}, 80 {{zio_checksum_SHA256, zio_checksum_SHA256}, 1, 0, 1, "sha256"}, 81 {{fletcher_4_native, fletcher_4_byteswap}, 0, 1, 0, "zilog2"}, 82 {{zio_checksum_off, zio_checksum_off}, 0, 0, 0, "noparity"}, 83 }; 84 85 enum zio_checksum 86 zio_checksum_select(enum zio_checksum child, enum zio_checksum parent) 87 { 88 ASSERT(child < ZIO_CHECKSUM_FUNCTIONS); 89 ASSERT(parent < ZIO_CHECKSUM_FUNCTIONS); 90 ASSERT(parent != ZIO_CHECKSUM_INHERIT && parent != ZIO_CHECKSUM_ON); 91 92 if (child == ZIO_CHECKSUM_INHERIT) 93 return (parent); 94 95 if (child == ZIO_CHECKSUM_ON) 96 return (ZIO_CHECKSUM_ON_VALUE); 97 98 return (child); 99 } 100 101 enum zio_checksum 102 zio_checksum_dedup_select(spa_t *spa, enum zio_checksum child, 103 enum zio_checksum parent) 104 { 105 ASSERT((child & ZIO_CHECKSUM_MASK) < ZIO_CHECKSUM_FUNCTIONS); 106 ASSERT((parent & ZIO_CHECKSUM_MASK) < ZIO_CHECKSUM_FUNCTIONS); 107 ASSERT(parent != ZIO_CHECKSUM_INHERIT && parent != ZIO_CHECKSUM_ON); 108 109 if (child == ZIO_CHECKSUM_INHERIT) 110 return (parent); 111 112 if (child == ZIO_CHECKSUM_ON) 113 return (spa_dedup_checksum(spa)); 114 115 if (child == (ZIO_CHECKSUM_ON | ZIO_CHECKSUM_VERIFY)) 116 return (spa_dedup_checksum(spa) | ZIO_CHECKSUM_VERIFY); 117 118 ASSERT(zio_checksum_table[child & ZIO_CHECKSUM_MASK].ci_dedup || 119 (child & ZIO_CHECKSUM_VERIFY) || child == ZIO_CHECKSUM_OFF); 120 121 return (child); 122 } 123 124 /* 125 * Set the external verifier for a gang block based on <vdev, offset, txg>, 126 * a tuple which is guaranteed to be unique for the life of the pool. 127 */ 128 static void 129 zio_checksum_gang_verifier(zio_cksum_t *zcp, blkptr_t *bp) 130 { 131 dva_t *dva = BP_IDENTITY(bp); 132 uint64_t txg = BP_PHYSICAL_BIRTH(bp); 133 134 ASSERT(BP_IS_GANG(bp)); 135 136 ZIO_SET_CHECKSUM(zcp, DVA_GET_VDEV(dva), DVA_GET_OFFSET(dva), txg, 0); 137 } 138 139 /* 140 * Set the external verifier for a label block based on its offset. 141 * The vdev is implicit, and the txg is unknowable at pool open time -- 142 * hence the logic in vdev_uberblock_load() to find the most recent copy. 143 */ 144 static void 145 zio_checksum_label_verifier(zio_cksum_t *zcp, uint64_t offset) 146 { 147 ZIO_SET_CHECKSUM(zcp, offset, 0, 0, 0); 148 } 149 150 /* 151 * Generate the checksum. 152 */ 153 void 154 zio_checksum_compute(zio_t *zio, enum zio_checksum checksum, 155 void *data, uint64_t size) 156 { 157 blkptr_t *bp = zio->io_bp; 158 uint64_t offset = zio->io_offset; 159 zio_checksum_info_t *ci = &zio_checksum_table[checksum]; 160 zio_cksum_t cksum; 161 162 ASSERT((uint_t)checksum < ZIO_CHECKSUM_FUNCTIONS); 163 ASSERT(ci->ci_func[0] != NULL); 164 165 if (ci->ci_eck) { 166 zio_eck_t *eck; 167 168 if (checksum == ZIO_CHECKSUM_ZILOG2) { 169 zil_chain_t *zilc = data; 170 171 size = P2ROUNDUP_TYPED(zilc->zc_nused, ZIL_MIN_BLKSZ, 172 uint64_t); 173 eck = &zilc->zc_eck; 174 } else { 175 eck = (zio_eck_t *)((char *)data + size) - 1; 176 } 177 if (checksum == ZIO_CHECKSUM_GANG_HEADER) 178 zio_checksum_gang_verifier(&eck->zec_cksum, bp); 179 else if (checksum == ZIO_CHECKSUM_LABEL) 180 zio_checksum_label_verifier(&eck->zec_cksum, offset); 181 else 182 bp->blk_cksum = eck->zec_cksum; 183 eck->zec_magic = ZEC_MAGIC; 184 ci->ci_func[0](data, size, &cksum); 185 eck->zec_cksum = cksum; 186 } else { 187 ci->ci_func[0](data, size, &bp->blk_cksum); 188 } 189 } 190 191 int 192 zio_checksum_error(zio_t *zio, zio_bad_cksum_t *info) 193 { 194 blkptr_t *bp = zio->io_bp; 195 uint_t checksum = (bp == NULL ? zio->io_prop.zp_checksum : 196 (BP_IS_GANG(bp) ? ZIO_CHECKSUM_GANG_HEADER : BP_GET_CHECKSUM(bp))); 197 int byteswap; 198 int error; 199 uint64_t size = (bp == NULL ? zio->io_size : 200 (BP_IS_GANG(bp) ? SPA_GANGBLOCKSIZE : BP_GET_PSIZE(bp))); 201 uint64_t offset = zio->io_offset; 202 void *data = zio->io_data; 203 zio_checksum_info_t *ci = &zio_checksum_table[checksum]; 204 zio_cksum_t actual_cksum, expected_cksum, verifier; 205 206 if (checksum >= ZIO_CHECKSUM_FUNCTIONS || ci->ci_func[0] == NULL) 207 return (SET_ERROR(EINVAL)); 208 209 if (ci->ci_eck) { 210 zio_eck_t *eck; 211 212 if (checksum == ZIO_CHECKSUM_ZILOG2) { 213 zil_chain_t *zilc = data; 214 uint64_t nused; 215 216 eck = &zilc->zc_eck; 217 if (eck->zec_magic == ZEC_MAGIC) 218 nused = zilc->zc_nused; 219 else if (eck->zec_magic == BSWAP_64(ZEC_MAGIC)) 220 nused = BSWAP_64(zilc->zc_nused); 221 else 222 return (SET_ERROR(ECKSUM)); 223 224 if (nused > size) 225 return (SET_ERROR(ECKSUM)); 226 227 size = P2ROUNDUP_TYPED(nused, ZIL_MIN_BLKSZ, uint64_t); 228 } else { 229 eck = (zio_eck_t *)((char *)data + size) - 1; 230 } 231 232 if (checksum == ZIO_CHECKSUM_GANG_HEADER) 233 zio_checksum_gang_verifier(&verifier, bp); 234 else if (checksum == ZIO_CHECKSUM_LABEL) 235 zio_checksum_label_verifier(&verifier, offset); 236 else 237 verifier = bp->blk_cksum; 238 239 byteswap = (eck->zec_magic == BSWAP_64(ZEC_MAGIC)); 240 241 if (byteswap) 242 byteswap_uint64_array(&verifier, sizeof (zio_cksum_t)); 243 244 expected_cksum = eck->zec_cksum; 245 eck->zec_cksum = verifier; 246 ci->ci_func[byteswap](data, size, &actual_cksum); 247 eck->zec_cksum = expected_cksum; 248 249 if (byteswap) 250 byteswap_uint64_array(&expected_cksum, 251 sizeof (zio_cksum_t)); 252 } else { 253 ASSERT(!BP_IS_GANG(bp)); 254 byteswap = BP_SHOULD_BYTESWAP(bp); 255 expected_cksum = bp->blk_cksum; 256 ci->ci_func[byteswap](data, size, &actual_cksum); 257 } 258 259 info->zbc_expected = expected_cksum; 260 info->zbc_actual = actual_cksum; 261 info->zbc_checksum_name = ci->ci_name; 262 info->zbc_byteswapped = byteswap; 263 info->zbc_injected = 0; 264 info->zbc_has_cksum = 1; 265 266 if (!ZIO_CHECKSUM_EQUAL(actual_cksum, expected_cksum)) 267 return (SET_ERROR(ECKSUM)); 268 269 if (zio_injection_enabled && !zio->io_error && 270 (error = zio_handle_fault_injection(zio, ECKSUM)) != 0) { 271 272 info->zbc_injected = 1; 273 return (error); 274 } 275 276 return (0); 277 } 278