--- /dev/null
+/*
+ * 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 2008 Sun Microsystems, Inc. All rights reserved.
+ * Use is subject to license terms.
+ */
+
+#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);
+}
+
+/*
+ * Set the external verifier for a gang block based on <vdev, offset, txg>,
+ * a tuple which is guaranteed to be unique for the life of the pool.
+ */
+static void
+zio_checksum_gang_verifier(zio_cksum_t *zcp, blkptr_t *bp)
+{
+ dva_t *dva = BP_IDENTITY(bp);
+ uint64_t txg = bp->blk_birth;
+
+ ASSERT(BP_IS_GANG(bp));
+
+ ZIO_SET_CHECKSUM(zcp, DVA_GET_VDEV(dva), DVA_GET_OFFSET(dva), txg, 0);
+}
+
+/*
+ * Set the external verifier for a label block based on its offset.
+ * The vdev is implicit, and the txg is unknowable at pool open time --
+ * hence the logic in vdev_uberblock_load() to find the most recent copy.
+ */
+static void
+zio_checksum_label_verifier(zio_cksum_t *zcp, uint64_t offset)
+{
+ ZIO_SET_CHECKSUM(zcp, offset, 0, 0, 0);
+}
+
+/*
+ * Generate the checksum.
+ */
+void
+zio_checksum_compute(zio_t *zio, enum zio_checksum checksum,
+ void *data, uint64_t size)
+{
+ blkptr_t *bp = zio->io_bp;
+ uint64_t offset = zio->io_offset;
+ 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((uint_t)checksum < ZIO_CHECKSUM_FUNCTIONS);
+ ASSERT(ci->ci_func[0] != NULL);
+
+ if (ci->ci_zbt) {
+ if (checksum == ZIO_CHECKSUM_GANG_HEADER)
+ zio_checksum_gang_verifier(&zbt->zbt_cksum, bp);
+ else if (checksum == ZIO_CHECKSUM_LABEL)
+ zio_checksum_label_verifier(&zbt->zbt_cksum, offset);
+ else
+ bp->blk_cksum = 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, &bp->blk_cksum);
+ }
+}
+
+int
+zio_checksum_error(zio_t *zio)
+{
+ blkptr_t *bp = zio->io_bp;
+ uint_t checksum = (bp == NULL ? zio->io_prop.zp_checksum :
+ (BP_IS_GANG(bp) ? ZIO_CHECKSUM_GANG_HEADER : BP_GET_CHECKSUM(bp)));
+ int byteswap;
+ void *data = zio->io_data;
+ uint64_t size = (bp == NULL ? zio->io_size :
+ (BP_IS_GANG(bp) ? SPA_GANGBLOCKSIZE : BP_GET_PSIZE(bp)));
+ uint64_t offset = zio->io_offset;
+ 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, verifier;
+
+ if (checksum >= ZIO_CHECKSUM_FUNCTIONS || ci->ci_func[0] == NULL)
+ return (EINVAL);
+
+ if (ci->ci_zbt) {
+ if (checksum == ZIO_CHECKSUM_GANG_HEADER)
+ zio_checksum_gang_verifier(&verifier, bp);
+ else if (checksum == ZIO_CHECKSUM_LABEL)
+ zio_checksum_label_verifier(&verifier, offset);
+ else
+ verifier = bp->blk_cksum;
+
+ byteswap = (zbt->zbt_magic == BSWAP_64(ZBT_MAGIC));
+
+ if (byteswap)
+ byteswap_uint64_array(&verifier, sizeof (zio_cksum_t));
+
+ expected_cksum = zbt->zbt_cksum;
+ zbt->zbt_cksum = verifier;
+ ci->ci_func[byteswap](data, size, &actual_cksum);
+ zbt->zbt_cksum = expected_cksum;
+
+ if (byteswap)
+ byteswap_uint64_array(&expected_cksum,
+ sizeof (zio_cksum_t));
+ } else {
+ ASSERT(!BP_IS_GANG(bp));
+ byteswap = BP_SHOULD_BYTESWAP(bp);
+ expected_cksum = bp->blk_cksum;
+ ci->ci_func[byteswap](data, size, &actual_cksum);
+ }
+
+ if (!ZIO_CHECKSUM_EQUAL(actual_cksum, expected_cksum))
+ return (ECKSUM);
+
+ if (zio_injection_enabled && !zio->io_error)
+ return (zio_handle_fault_injection(zio, ECKSUM));
+
+ return (0);
+}
git://git.camperquake.de / zfs.git / blobdiff