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author | pjd <pjd@FreeBSD.org> | 2007-04-06 01:09:06 +0000 |
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committer | pjd <pjd@FreeBSD.org> | 2007-04-06 01:09:06 +0000 |
commit | 3b005d330261f33318ca1ee3fef1940237fd788b (patch) | |
tree | 3061c8734d9ce560165e672836837a0f411a83c9 /sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zio_checksum.c | |
parent | 3be454b8211f48e634e6587f53807d3b5013e973 (diff) | |
download | FreeBSD-src-3b005d330261f33318ca1ee3fef1940237fd788b.zip FreeBSD-src-3b005d330261f33318ca1ee3fef1940237fd788b.tar.gz |
Please welcome ZFS - The last word in file systems.
ZFS file system was ported from OpenSolaris operating system. The code in under
CDDL license.
I'd like to thank all SUN developers that created this great piece of software.
Supported by: Wheel LTD (http://www.wheel.pl/)
Supported by: The FreeBSD Foundation (http://www.freebsdfoundation.org/)
Supported by: Sentex (http://www.sentex.net/)
Diffstat (limited to 'sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zio_checksum.c')
-rw-r--r-- | sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zio_checksum.c | 172 |
1 files changed, 172 insertions, 0 deletions
diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zio_checksum.c b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zio_checksum.c new file mode 100644 index 0000000..f0d9a14 --- /dev/null +++ b/sys/cddl/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); +} |