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