Initial Linux ZFS GIT Repo

2026-05-29 18:24:11 +03:00 · 2008-11-20 12:01:55 -08:00
commit 34dc7c2f25
444 changed files with 187636 additions and 0 deletions
@@ -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	"@(#)zio_checksum.c	1.6	06/11/10 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);
+}