diff options
Diffstat (limited to 'sys/contrib/opensolaris/uts/common/fs/zfs/zio_checksum.c')
| -rw-r--r-- | sys/contrib/opensolaris/uts/common/fs/zfs/zio_checksum.c | 172 |
1 files changed, 172 insertions, 0 deletions
diff --git a/sys/contrib/opensolaris/uts/common/fs/zfs/zio_checksum.c b/sys/contrib/opensolaris/uts/common/fs/zfs/zio_checksum.c new file mode 100644 index 0000000..f0d9a14 --- /dev/null +++ b/sys/contrib/opensolaris/uts/common/fs/zfs/zio_checksum.c @@ -0,0 +1,172 @@ +/* + * CDDL HEADER START + * + * The contents of this file are subject to the terms of the + * Common Development and Distribution License (the "License"). + * You may not use this file except in compliance with the License. + * + * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE + * or http://www.opensolaris.org/os/licensing. + * See the License for the specific language governing permissions + * and limitations under the License. + * + * When distributing Covered Code, include this CDDL HEADER in each + * file and include the License file at usr/src/OPENSOLARIS.LICENSE. + * If applicable, add the following below this CDDL HEADER, with the + * fields enclosed by brackets "[]" replaced with your own identifying + * information: Portions Copyright [yyyy] [name of copyright owner] + * + * CDDL HEADER END + */ +/* + * Copyright 2006 Sun Microsystems, Inc. All rights reserved. + * Use is subject to license terms. + */ + +#pragma ident "%Z%%M% %I% %E% SMI" + +#include <sys/zfs_context.h> +#include <sys/spa.h> +#include <sys/zio.h> +#include <sys/zio_checksum.h> + +/* + * Checksum vectors. + * + * In the SPA, everything is checksummed. We support checksum vectors + * for three distinct reasons: + * + * 1. Different kinds of data need different levels of protection. + * For SPA metadata, we always want a very strong checksum. + * For user data, we let users make the trade-off between speed + * and checksum strength. + * + * 2. Cryptographic hash and MAC algorithms are an area of active research. + * It is likely that in future hash functions will be at least as strong + * as current best-of-breed, and may be substantially faster as well. + * We want the ability to take advantage of these new hashes as soon as + * they become available. + * + * 3. If someone develops hardware that can compute a strong hash quickly, + * we want the ability to take advantage of that hardware. + * + * Of course, we don't want a checksum upgrade to invalidate existing + * data, so we store the checksum *function* in five bits of the DVA. + * This gives us room for up to 32 different checksum functions. + * + * When writing a block, we always checksum it with the latest-and-greatest + * checksum function of the appropriate strength. When reading a block, + * we compare the expected checksum against the actual checksum, which we + * compute via the checksum function specified in the DVA encoding. + */ + +/*ARGSUSED*/ +static void +zio_checksum_off(const void *buf, uint64_t size, zio_cksum_t *zcp) +{ + ZIO_SET_CHECKSUM(zcp, 0, 0, 0, 0); +} + +zio_checksum_info_t zio_checksum_table[ZIO_CHECKSUM_FUNCTIONS] = { + {{NULL, NULL}, 0, 0, "inherit"}, + {{NULL, NULL}, 0, 0, "on"}, + {{zio_checksum_off, zio_checksum_off}, 0, 0, "off"}, + {{zio_checksum_SHA256, zio_checksum_SHA256}, 1, 1, "label"}, + {{zio_checksum_SHA256, zio_checksum_SHA256}, 1, 1, "gang_header"}, + {{fletcher_2_native, fletcher_2_byteswap}, 0, 1, "zilog"}, + {{fletcher_2_native, fletcher_2_byteswap}, 0, 0, "fletcher2"}, + {{fletcher_4_native, fletcher_4_byteswap}, 1, 0, "fletcher4"}, + {{zio_checksum_SHA256, zio_checksum_SHA256}, 1, 0, "SHA256"}, +}; + +uint8_t +zio_checksum_select(uint8_t child, uint8_t parent) +{ + ASSERT(child < ZIO_CHECKSUM_FUNCTIONS); + ASSERT(parent < ZIO_CHECKSUM_FUNCTIONS); + ASSERT(parent != ZIO_CHECKSUM_INHERIT && parent != ZIO_CHECKSUM_ON); + + if (child == ZIO_CHECKSUM_INHERIT) + return (parent); + + if (child == ZIO_CHECKSUM_ON) + return (ZIO_CHECKSUM_ON_VALUE); + + return (child); +} + +/* + * Generate the checksum. + */ +void +zio_checksum(uint_t checksum, zio_cksum_t *zcp, void *data, uint64_t size) +{ + zio_block_tail_t *zbt = (zio_block_tail_t *)((char *)data + size) - 1; + zio_checksum_info_t *ci = &zio_checksum_table[checksum]; + zio_cksum_t zbt_cksum; + + ASSERT(checksum < ZIO_CHECKSUM_FUNCTIONS); + ASSERT(ci->ci_func[0] != NULL); + + if (ci->ci_zbt) { + *zcp = zbt->zbt_cksum; + zbt->zbt_magic = ZBT_MAGIC; + ci->ci_func[0](data, size, &zbt_cksum); + zbt->zbt_cksum = zbt_cksum; + } else { + ci->ci_func[0](data, size, zcp); + } +} + +int +zio_checksum_error(zio_t *zio) +{ + blkptr_t *bp = zio->io_bp; + zio_cksum_t zc = bp->blk_cksum; + uint_t checksum = BP_IS_GANG(bp) ? ZIO_CHECKSUM_GANG_HEADER : + BP_GET_CHECKSUM(bp); + int byteswap = BP_SHOULD_BYTESWAP(bp); + void *data = zio->io_data; + uint64_t size = ZIO_GET_IOSIZE(zio); + zio_block_tail_t *zbt = (zio_block_tail_t *)((char *)data + size) - 1; + zio_checksum_info_t *ci = &zio_checksum_table[checksum]; + zio_cksum_t actual_cksum, expected_cksum; + + if (checksum >= ZIO_CHECKSUM_FUNCTIONS || ci->ci_func[0] == NULL) + return (EINVAL); + + if (ci->ci_zbt) { + if (checksum == ZIO_CHECKSUM_GANG_HEADER) + zio_set_gang_verifier(zio, &zc); + + if (zbt->zbt_magic == BSWAP_64(ZBT_MAGIC)) { + expected_cksum = zbt->zbt_cksum; + byteswap_uint64_array(&expected_cksum, + sizeof (zio_cksum_t)); + zbt->zbt_cksum = zc; + byteswap_uint64_array(&zbt->zbt_cksum, + sizeof (zio_cksum_t)); + ci->ci_func[1](data, size, &actual_cksum); + zbt->zbt_cksum = expected_cksum; + byteswap_uint64_array(&zbt->zbt_cksum, + sizeof (zio_cksum_t)); + } else { + expected_cksum = zbt->zbt_cksum; + zbt->zbt_cksum = zc; + ci->ci_func[0](data, size, &actual_cksum); + zbt->zbt_cksum = expected_cksum; + } + zc = expected_cksum; + } else { + ASSERT(!BP_IS_GANG(bp)); + ci->ci_func[byteswap](data, size, &actual_cksum); + } + + if (!ZIO_CHECKSUM_EQUAL(actual_cksum, zc)) + return (ECKSUM); + + if (zio_injection_enabled && !zio->io_error) + return (zio_handle_fault_injection(zio, ECKSUM)); + + return (0); +} |
