MFV r254750:

Add support of Illumos dumps on zvol over RAID-Z.

Note that this only adds the features.  FreeBSD would
still need more work to support dumping on zvols.

Illumos ZFS issues:
  2932 support crash dumps to raidz, etc. pools

MFC after:	1 month
Approved by:	re (ZFS blanket)

9 files changed, 380 insertions, 45 deletions

diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dbuf.c b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dbuf.c
index 92ee7c33e656..4d02a1d7957c 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dbuf.c
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dbuf.c
@@ -23,6 +23,7 @@
  * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
  * Copyright (c) 2013 by Delphix. All rights reserved.
  * Copyright (c) 2013 by Saso Kiselkov. All rights reserved.
+ * Copyright (c) 2013, Joyent, Inc. All rights reserved.
  */
 
 #include <sys/zfs_context.h>
@@ -2755,7 +2756,8 @@ dbuf_write(dbuf_dirty_record_t *dr, arc_buf_t *data, dmu_tx_t *tx)
 		    dr->dt.dl.dr_copies, dr->dt.dl.dr_nopwrite);
 		mutex_exit(&db->db_mtx);
 	} else if (db->db_state == DB_NOFILL) {
-		ASSERT(zp.zp_checksum == ZIO_CHECKSUM_OFF);
+		ASSERT(zp.zp_checksum == ZIO_CHECKSUM_OFF ||
+		    zp.zp_checksum == ZIO_CHECKSUM_NOPARITY);
 		dr->dr_zio = zio_write(zio, os->os_spa, txg,
 		    db->db_blkptr, NULL, db->db.db_size, &zp,
 		    dbuf_write_nofill_ready, dbuf_write_nofill_done, db,
diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu.c b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu.c
index 54decd6ccece..9e661be2e980 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu.c
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu.c
@@ -22,8 +22,8 @@
  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
  * Copyright (c) 2013 by Delphix. All rights reserved.
  */
-
 /* Copyright (c) 2013 by Saso Kiselkov. All rights reserved. */
+/* Copyright (c) 2013, Joyent, Inc. All rights reserved. */
 
 #include <sys/dmu.h>
 #include <sys/dmu_impl.h>
@@ -1610,7 +1610,7 @@ dmu_write_policy(objset_t *os, dnode_t *dn, int level, int wp, zio_prop_t *zp)
 		 * pipeline.
 		 */
 		compress = ZIO_COMPRESS_OFF;
-		checksum = ZIO_CHECKSUM_OFF;
+		checksum = ZIO_CHECKSUM_NOPARITY;
 	} else {
 		compress = zio_compress_select(dn->dn_compress, compress);
 
diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/vdev_disk.h b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/vdev_disk.h
index b748571ea0c3..9055d0ed6565 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/vdev_disk.h
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/vdev_disk.h
@@ -21,13 +21,12 @@
 /*
  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
+ * Copyright (c) 2013 Joyent, Inc. All rights reserved.
  */
 
 #ifndef _SYS_VDEV_DISK_H
 #define	_SYS_VDEV_DISK_H
 
-#pragma ident	"%Z%%M%	%I%	%E% SMI"
-
 #include <sys/vdev.h>
 #ifdef _KERNEL
 #include <sys/buf.h>
@@ -40,14 +39,23 @@
 extern "C" {
 #endif
 
+#ifdef _KERNEL
 typedef struct vdev_disk {
 	ddi_devid_t	vd_devid;
 	char		*vd_minor;
 	ldi_handle_t	vd_lh;
 } vdev_disk_t;
+#endif
 
+extern int vdev_disk_physio(vdev_t *,
+    caddr_t, size_t, uint64_t, int, boolean_t);
+
+/*
+ * Since vdev_disk.c is not compiled into libzpool, this function should only be
+ * defined in the zfs kernel module.
+ */
 #ifdef _KERNEL
-extern int vdev_disk_physio(ldi_handle_t, caddr_t, size_t, uint64_t, int);
+extern int vdev_disk_ldi_physio(ldi_handle_t, caddr_t, size_t, uint64_t, int);
 #endif
 #ifdef	__cplusplus
 }
diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/vdev_raidz.h b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/vdev_raidz.h
new file mode 100644
index 000000000000..e771e668fda6
--- /dev/null
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/vdev_raidz.h
@@ -0,0 +1,50 @@
+/*
+ * 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 (c) 2013, Joyent, Inc. All rights reserved.
+ */
+
+#ifndef _SYS_VDEV_RAIDZ_H
+#define	_SYS_VDEV_RAIDZ_H
+
+#include <sys/vdev.h>
+#ifdef illumos
+#include <sys/semaphore.h>
+#ifdef _KERNEL
+#include <sys/ddi.h>
+#include <sys/sunldi.h>
+#include <sys/sunddi.h>
+#endif
+#endif
+
+#ifdef	__cplusplus
+extern "C" {
+#endif
+
+#ifdef _KERNEL
+extern int vdev_raidz_physio(vdev_t *,
+    caddr_t, size_t, uint64_t, uint64_t, boolean_t, boolean_t);
+#endif
+#ifdef	__cplusplus
+}
+#endif
+
+#endif	/* _SYS_VDEV_RAIDZ_H */
diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/zio.h b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/zio.h
index 342e7c1a61bd..b001e111078a 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/zio.h
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/zio.h
@@ -23,6 +23,7 @@
  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
  * Copyright (c) 2012 by Delphix. All rights reserved.
  * Copyright (c) 2013 by Saso Kiselkov. All rights reserved.
+ * Copyright (c) 2013, Joyent, Inc. All rights reserved.
  */
 
 #ifndef _ZIO_H
@@ -79,6 +80,7 @@ enum zio_checksum {
 	ZIO_CHECKSUM_FLETCHER_4,
 	ZIO_CHECKSUM_SHA256,
 	ZIO_CHECKSUM_ZILOG2,
+	ZIO_CHECKSUM_NOPARITY,
 	ZIO_CHECKSUM_FUNCTIONS
 };
 
diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/vdev_disk.c b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/vdev_disk.c
index 00682c89cab7..3d119661c1a2 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/vdev_disk.c
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/vdev_disk.c
@@ -22,6 +22,7 @@
  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
  * Copyright (c) 2013 by Delphix. All rights reserved.
  * Copyright 2013 Nexenta Systems, Inc.  All rights reserved.
+ * Copyright 2013 Joyent, Inc.  All rights reserved.
  */
 
 #include <sys/zfs_context.h>
@@ -431,8 +432,29 @@ vdev_disk_close(vdev_t *vd)
 }
 
 int
-vdev_disk_physio(ldi_handle_t vd_lh, caddr_t data, size_t size,
-    uint64_t offset, int flags)
+vdev_disk_physio(vdev_t *vd, caddr_t data,
+    size_t size, uint64_t offset, int flags, boolean_t isdump)
+{
+	vdev_disk_t *dvd = vd->vdev_tsd;
+
+	ASSERT(vd->vdev_ops == &vdev_disk_ops);
+
+	/*
+	 * If in the context of an active crash dump, use the ldi_dump(9F)
+	 * call instead of ldi_strategy(9F) as usual.
+	 */
+	if (isdump) {
+		ASSERT3P(dvd, !=, NULL);
+		return (ldi_dump(dvd->vd_lh, data, lbtodb(offset),
+		    lbtodb(size)));
+	}
+
+	return (vdev_disk_ldi_physio(dvd->vd_lh, data, size, offset, flags));
+}
+
+int
+vdev_disk_ldi_physio(ldi_handle_t vd_lh, caddr_t data,
+    size_t size, uint64_t offset, int flags)
 {
 	buf_t *bp;
 	int error = 0;
@@ -680,7 +702,7 @@ vdev_disk_read_rootlabel(char *devpath, char *devid, nvlist_t **config)
 
 		/* read vdev label */
 		offset = vdev_label_offset(size, l, 0);
-		if (vdev_disk_physio(vd_lh, (caddr_t)label,
+		if (vdev_disk_ldi_physio(vd_lh, (caddr_t)label,
 		    VDEV_SKIP_SIZE + VDEV_PHYS_SIZE, offset, B_READ) != 0)
 			continue;
 
diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/vdev_raidz.c b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/vdev_raidz.c
index 5e3c6c7a8a0d..f2fd29d713eb 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/vdev_raidz.c
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/vdev_raidz.c
@@ -22,15 +22,22 @@
 /*
  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
  * Copyright (c) 2013 by Delphix. All rights reserved.
+ * Copyright (c) 2013, Joyent, Inc. All rights reserved.
  */
 
 #include <sys/zfs_context.h>
 #include <sys/spa.h>
 #include <sys/vdev_impl.h>
+#ifdef illumos
+#include <sys/vdev_disk.h>
+#endif
+#include <sys/vdev_file.h>
+#include <sys/vdev_raidz.h>
 #include <sys/zio.h>
 #include <sys/zio_checksum.h>
 #include <sys/fs/zfs.h>
 #include <sys/fm/fs/zfs.h>
+#include <sys/bio.h>
 
 /*
  * Virtual device vector for RAID-Z.
@@ -154,6 +161,8 @@ typedef struct raidz_map {
 	VDEV_RAIDZ_64MUL_2((x), mask); \
 }
 
+#define	VDEV_LABEL_OFFSET(x)	(x + VDEV_LABEL_START_SIZE)
+
 /*
  * Force reconstruction to use the general purpose method.
  */
@@ -437,14 +446,14 @@ static const zio_vsd_ops_t vdev_raidz_vsd_ops = {
  * the number of children in the target vdev.
  */
 static raidz_map_t *
-vdev_raidz_map_alloc(zio_t *zio, uint64_t unit_shift, uint64_t dcols,
-    uint64_t nparity)
+vdev_raidz_map_alloc(caddr_t data, uint64_t size, uint64_t offset, boolean_t dofree,
+    uint64_t unit_shift, uint64_t dcols, uint64_t nparity)
 {
 	raidz_map_t *rm;
 	/* The starting RAIDZ (parent) vdev sector of the block. */
-	uint64_t b = zio->io_offset >> unit_shift;
+	uint64_t b = offset >> unit_shift;
 	/* The zio's size in units of the vdev's minimum sector size. */
-	uint64_t s = zio->io_size >> unit_shift;
+	uint64_t s = size >> unit_shift;
 	/* The first column for this stripe. */
 	uint64_t f = b % dcols;
 	/* The starting byte offset on each child vdev. */
@@ -532,13 +541,13 @@ vdev_raidz_map_alloc(zio_t *zio, uint64_t unit_shift, uint64_t dcols,
 	ASSERT3U(rm->rm_asize - asize, ==, rm->rm_nskip << unit_shift);
 	ASSERT3U(rm->rm_nskip, <=, nparity);
 
-	if (zio->io_type != ZIO_TYPE_FREE) {
+	if (!dofree) {
 		for (c = 0; c < rm->rm_firstdatacol; c++) {
 			rm->rm_col[c].rc_data =
 			    zio_buf_alloc(rm->rm_col[c].rc_size);
 		}
 
-		rm->rm_col[c].rc_data = zio->io_data;
+		rm->rm_col[c].rc_data = data;
 
 		for (c = c + 1; c < acols; c++) {
 			rm->rm_col[c].rc_data =
@@ -570,7 +579,7 @@ vdev_raidz_map_alloc(zio_t *zio, uint64_t unit_shift, uint64_t dcols,
 	ASSERT(rm->rm_cols >= 2);
 	ASSERT(rm->rm_col[0].rc_size == rm->rm_col[1].rc_size);
 
-	if (rm->rm_firstdatacol == 1 && (zio->io_offset & (1ULL << 20))) {
+	if (rm->rm_firstdatacol == 1 && (offset & (1ULL << 20))) {
 		devidx = rm->rm_col[0].rc_devidx;
 		o = rm->rm_col[0].rc_offset;
 		rm->rm_col[0].rc_devidx = rm->rm_col[1].rc_devidx;
@@ -582,8 +591,6 @@ vdev_raidz_map_alloc(zio_t *zio, uint64_t unit_shift, uint64_t dcols,
 			rm->rm_skipstart = 1;
 	}
 
-	zio->io_vsd = rm;
-	zio->io_vsd_ops = &vdev_raidz_vsd_ops;
 	return (rm);
 }
 
@@ -993,12 +1000,9 @@ vdev_raidz_reconstruct_pq(raidz_map_t *rm, int *tgts, int ntgts)
  *           ~~                               ~~
  *           __                               __
  *           |  1   1   1   1   1   1   1   1  |
- *           | 128  64  32  16  8   4   2   1  |
  *           |  19 205 116  29  64  16  4   1  |
  *           |  1   0   0   0   0   0   0   0  |
- *           |  0   1   0   0   0   0   0   0  |
- *  (V|I)' = |  0   0   1   0   0   0   0   0  |
- *           |  0   0   0   1   0   0   0   0  |
+ *  (V|I)' = |  0   0   0   1   0   0   0   0  |
  *           |  0   0   0   0   1   0   0   0  |
  *           |  0   0   0   0   0   1   0   0  |
  *           |  0   0   0   0   0   0   1   0  |
@@ -1532,6 +1536,154 @@ vdev_raidz_close(vdev_t *vd)
 		vdev_close(vd->vdev_child[c]);
 }
 
+#ifdef illumos
+/*
+ * Handle a read or write I/O to a RAID-Z dump device.
+ *
+ * The dump device is in a unique situation compared to other ZFS datasets:
+ * writing to this device should be as simple and fast as possible.  In
+ * addition, durability matters much less since the dump will be extracted
+ * once the machine reboots.  For that reason, this function eschews parity for
+ * performance and simplicity.  The dump device uses the checksum setting
+ * ZIO_CHECKSUM_NOPARITY to indicate that parity is not maintained for this
+ * dataset.
+ *
+ * Blocks of size 128 KB have been preallocated for this volume.  I/Os less than
+ * 128 KB will not fill an entire block; in addition, they may not be properly
+ * aligned.  In that case, this function uses the preallocated 128 KB block and
+ * omits reading or writing any "empty" portions of that block, as opposed to
+ * allocating a fresh appropriately-sized block.
+ *
+ * Looking at an example of a 32 KB I/O to a RAID-Z vdev with 5 child vdevs:
+ *
+ *     vdev_raidz_io_start(data, size: 32 KB, offset: 64 KB)
+ *
+ * If this were a standard RAID-Z dataset, a block of at least 40 KB would be
+ * allocated which spans all five child vdevs.  8 KB of data would be written to
+ * each of four vdevs, with the fifth containing the parity bits.
+ *
+ *       parity    data     data     data     data
+ *     |   PP   |   XX   |   XX   |   XX   |   XX   |
+ *         ^        ^        ^        ^        ^
+ *         |        |        |        |        |
+ *   8 KB parity    ------8 KB data blocks------
+ *
+ * However, when writing to the dump device, the behavior is different:
+ *
+ *     vdev_raidz_physio(data, size: 32 KB, offset: 64 KB)
+ *
+ * Unlike the normal RAID-Z case in which the block is allocated based on the
+ * I/O size, reads and writes here always use a 128 KB logical I/O size.  If the
+ * I/O size is less than 128 KB, only the actual portions of data are written.
+ * In this example the data is written to the third data vdev since that vdev
+ * contains the offset [64 KB, 96 KB).
+ *
+ *       parity    data     data     data     data
+ *     |        |        |        |   XX   |        |
+ *                                    ^
+ *                                    |
+ *                             32 KB data block
+ *
+ * As a result, an individual I/O may not span all child vdevs; moreover, a
+ * small I/O may only operate on a single child vdev.
+ *
+ * Note that since there are no parity bits calculated or written, this format
+ * remains the same no matter how many parity bits are used in a normal RAID-Z
+ * stripe.  On a RAID-Z3 configuration with seven child vdevs, the example above
+ * would look like:
+ *
+ *       parity   parity   parity    data     data     data     data
+ *     |        |        |        |        |        |   XX   |        |
+ *                                                      ^
+ *                                                      |
+ *                                               32 KB data block
+ */
+int
+vdev_raidz_physio(vdev_t *vd, caddr_t data, size_t size,
+    uint64_t offset, uint64_t origoffset, boolean_t doread, boolean_t isdump)
+{
+	vdev_t *tvd = vd->vdev_top;
+	vdev_t *cvd;
+	raidz_map_t *rm;
+	raidz_col_t *rc;
+	int c, err = 0;
+
+	uint64_t start, end, colstart, colend;
+	uint64_t coloffset, colsize, colskip;
+
+	int flags = doread ? BIO_READ : BIO_WRITE;
+
+#ifdef	_KERNEL
+
+	/*
+	 * Don't write past the end of the block
+	 */
+	VERIFY3U(offset + size, <=, origoffset + SPA_MAXBLOCKSIZE);
+
+	start = offset;
+	end = start + size;
+
+	/*
+	 * Allocate a RAID-Z map for this block.  Note that this block starts
+	 * from the "original" offset, this is, the offset of the extent which
+	 * contains the requisite offset of the data being read or written.
+	 *
+	 * Even if this I/O operation doesn't span the full block size, let's
+	 * treat the on-disk format as if the only blocks are the complete 128
+	 * KB size.
+	 */
+	rm = vdev_raidz_map_alloc(data - (offset - origoffset),
+	    SPA_MAXBLOCKSIZE, origoffset, B_FALSE, tvd->vdev_ashift, vd->vdev_children,
+	    vd->vdev_nparity);
+
+	coloffset = origoffset;
+
+	for (c = rm->rm_firstdatacol; c < rm->rm_cols;
+	    c++, coloffset += rc->rc_size) {
+		rc = &rm->rm_col[c];
+		cvd = vd->vdev_child[rc->rc_devidx];
+
+		/*
+		 * Find the start and end of this column in the RAID-Z map,
+		 * keeping in mind that the stated size and offset of the
+		 * operation may not fill the entire column for this vdev.
+		 *
+		 * If any portion of the data spans this column, issue the
+		 * appropriate operation to the vdev.
+		 */
+		if (coloffset + rc->rc_size <= start)
+			continue;
+		if (coloffset >= end)
+			continue;
+
+		colstart = MAX(coloffset, start);
+		colend = MIN(end, coloffset + rc->rc_size);
+		colsize = colend - colstart;
+		colskip = colstart - coloffset;
+
+		VERIFY3U(colsize, <=, rc->rc_size);
+		VERIFY3U(colskip, <=, rc->rc_size);
+
+		/*
+		 * Note that the child vdev will have a vdev label at the start
+		 * of its range of offsets, hence the need for
+		 * VDEV_LABEL_OFFSET().  See zio_vdev_child_io() for another
+		 * example of why this calculation is needed.
+		 */
+		if ((err = vdev_disk_physio(cvd,
+		    ((char *)rc->rc_data) + colskip, colsize,
+		    VDEV_LABEL_OFFSET(rc->rc_offset) + colskip,
+		    flags, isdump)) != 0)
+			break;
+	}
+
+	vdev_raidz_map_free(rm);
+#endif	/* KERNEL */
+
+	return (err);
+}
+#endif
+
 static uint64_t
 vdev_raidz_asize(vdev_t *vd, uint64_t psize)
 {
@@ -1584,9 +1736,14 @@ vdev_raidz_io_start(zio_t *zio)
 	raidz_col_t *rc;
 	int c, i;
 
-	rm = vdev_raidz_map_alloc(zio, tvd->vdev_ashift, vd->vdev_children,
+	rm = vdev_raidz_map_alloc(zio->io_data, zio->io_size, zio->io_offset,
+	    zio->io_type == ZIO_TYPE_FREE,
+	    tvd->vdev_ashift, vd->vdev_children,
 	    vd->vdev_nparity);
 
+	zio->io_vsd = rm;
+	zio->io_vsd_ops = &vdev_raidz_vsd_ops;
+
 	ASSERT3U(rm->rm_asize, ==, vdev_psize_to_asize(vd, zio->io_size));
 
 	if (zio->io_type == ZIO_TYPE_FREE) {
@@ -1729,6 +1886,13 @@ raidz_parity_verify(zio_t *zio, raidz_map_t *rm)
 	int c, ret = 0;
 	raidz_col_t *rc;
 
+	blkptr_t *bp = zio->io_bp;
+	enum zio_checksum checksum = (bp == NULL ? zio->io_prop.zp_checksum :
+	    (BP_IS_GANG(bp) ? ZIO_CHECKSUM_GANG_HEADER : BP_GET_CHECKSUM(bp)));
+
+	if (checksum == ZIO_CHECKSUM_NOPARITY)
+		return (ret);
+
 	for (c = 0; c < rm->rm_firstdatacol; c++) {
 		rc = &rm->rm_col[c];
 		if (!rc->rc_tried || rc->rc_error != 0)
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
index bc7331764c7b..d1c60c3ffaba 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zio_checksum.c
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zio_checksum.c
@@ -21,6 +21,7 @@
 /*
  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
  * Copyright (c) 2013 by Delphix. All rights reserved.
+ * Copyright (c) 2013, Joyent, Inc. All rights reserved.
  */
 
 #include <sys/zfs_context.h>
@@ -78,6 +79,7 @@ zio_checksum_info_t zio_checksum_table[ZIO_CHECKSUM_FUNCTIONS] = {
 	{{fletcher_4_native,	fletcher_4_byteswap},	1, 0, 0, "fletcher4"},
 	{{zio_checksum_SHA256,	zio_checksum_SHA256},	1, 0, 1, "sha256"},
 	{{fletcher_4_native,	fletcher_4_byteswap},	0, 1, 0, "zilog2"},
+	{{zio_checksum_off,	zio_checksum_off},	0, 0, 0, "noparity"},
 };
 
 enum zio_checksum
diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zvol.c b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zvol.c
index 60d7a49cc376..72d45025a88d 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zvol.c
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zvol.c
@@ -24,6 +24,7 @@
  * Copyright (c) 2006-2010 Pawel Jakub Dawidek <pjd@FreeBSD.org>
  * All rights reserved.
  * Copyright (c) 2013 by Delphix. All rights reserved.
+ * Copyright (c) 2013, Joyent, Inc. All rights reserved.
  */
 
 /* Portions Copyright 2010 Robert Milkowski */
@@ -60,6 +61,7 @@
 #include <sys/stat.h>
 #include <sys/zap.h>
 #include <sys/spa.h>
+#include <sys/spa_impl.h>
 #include <sys/zio.h>
 #include <sys/dmu_traverse.h>
 #include <sys/dnode.h>
@@ -77,9 +79,14 @@
 #include <sys/zfs_znode.h>
 #include <sys/zfs_rlock.h>
 #include <sys/vdev_impl.h>
+#include <sys/vdev_raidz.h>
 #include <sys/zvol.h>
 #include <sys/zil_impl.h>
 #include <sys/dbuf.h>
+#include <sys/dmu_tx.h>
+#include <sys/zfeature.h>
+#include <sys/zio_checksum.h>
+
 #include <geom/geom.h>
 
 #include "zfs_namecheck.h"
@@ -1158,27 +1165,28 @@ zvol_log_write(zvol_state_t *zv, dmu_tx_t *tx, offset_t off, ssize_t resid,
 
 #ifdef sun
 static int
-zvol_dumpio_vdev(vdev_t *vd, void *addr, uint64_t offset, uint64_t size,
-    boolean_t doread, boolean_t isdump)
+zvol_dumpio_vdev(vdev_t *vd, void *addr, uint64_t offset, uint64_t origoffset,
+    uint64_t size, boolean_t doread, boolean_t isdump)
 {
 	vdev_disk_t *dvd;
 	int c;
 	int numerrors = 0;
 
-	for (c = 0; c < vd->vdev_children; c++) {
-		ASSERT(vd->vdev_ops == &vdev_mirror_ops ||
-		    vd->vdev_ops == &vdev_replacing_ops ||
-		    vd->vdev_ops == &vdev_spare_ops);
-		int err = zvol_dumpio_vdev(vd->vdev_child[c],
-		    addr, offset, size, doread, isdump);
-		if (err != 0) {
-			numerrors++;
-		} else if (doread) {
-			break;
+	if (vd->vdev_ops == &vdev_mirror_ops ||
+	    vd->vdev_ops == &vdev_replacing_ops ||
+	    vd->vdev_ops == &vdev_spare_ops) {
+		for (c = 0; c < vd->vdev_children; c++) {
+			int err = zvol_dumpio_vdev(vd->vdev_child[c],
+			    addr, offset, origoffset, size, doread, isdump);
+			if (err != 0) {
+				numerrors++;
+			} else if (doread) {
+				break;
+			}
 		}
 	}
 
-	if (!vd->vdev_ops->vdev_op_leaf)
+	if (!vd->vdev_ops->vdev_op_leaf && vd->vdev_ops != &vdev_raidz_ops)
 		return (numerrors < vd->vdev_children ? 0 : EIO);
 
 	if (doread && !vdev_readable(vd))
@@ -1186,19 +1194,26 @@ zvol_dumpio_vdev(vdev_t *vd, void *addr, uint64_t offset, uint64_t size,
 	else if (!doread && !vdev_writeable(vd))
 		return (SET_ERROR(EIO));
 
-	dvd = vd->vdev_tsd;
-	ASSERT3P(dvd, !=, NULL);
+	if (vd->vdev_ops == &vdev_raidz_ops) {
+		return (vdev_raidz_physio(vd,
+		    addr, size, offset, origoffset, doread, isdump));
+	}
+
 	offset += VDEV_LABEL_START_SIZE;
 
 	if (ddi_in_panic() || isdump) {
 		ASSERT(!doread);
 		if (doread)
 			return (SET_ERROR(EIO));
+		dvd = vd->vdev_tsd;
+		ASSERT3P(dvd, !=, NULL);
 		return (ldi_dump(dvd->vd_lh, addr, lbtodb(offset),
 		    lbtodb(size)));
 	} else {
-		return (vdev_disk_physio(dvd->vd_lh, addr, size, offset,
-		    doread ? B_READ : B_WRITE));
+		dvd = vd->vdev_tsd;
+		ASSERT3P(dvd, !=, NULL);
+		return (vdev_disk_ldi_physio(dvd->vd_lh, addr, size,
+		    offset, doread ? B_READ : B_WRITE));
 	}
 }
 
@@ -1233,7 +1248,8 @@ zvol_dumpio(zvol_state_t *zv, void *addr, uint64_t offset, uint64_t size,
 
 	vd = vdev_lookup_top(spa, DVA_GET_VDEV(&ze->ze_dva));
 	offset += DVA_GET_OFFSET(&ze->ze_dva);
-	error = zvol_dumpio_vdev(vd, addr, offset, size, doread, isdump);
+	error = zvol_dumpio_vdev(vd, addr, offset, DVA_GET_OFFSET(&ze->ze_dva),
+	    size, doread, isdump);
 
 	if (!ddi_in_panic())
 		spa_config_exit(spa, SCL_STATE, FTAG);
@@ -1253,6 +1269,7 @@ zvol_strategy(struct bio *bp)
 	rl_t *rl;
 	int error = 0;
 	boolean_t doread = (bp->bio_cmd == BIO_READ);
+	boolean_t is_dumpified;
 	boolean_t sync;
 
 	if (zv == NULL) {
@@ -1279,7 +1296,13 @@ zvol_strategy(struct bio *bp)
 		return (0);
 	}
 
-        sync = !doread && zv->zv_objset->os_sync == ZFS_SYNC_ALWAYS;
+#ifdef illumos
+	is_dumpified = zv->zv_flags & ZVOL_DUMPIFIED;
+#else
+	is_dumpified = B_FALSE;
+#endif
+        sync = !doread && !is_dumpified &&
+	    zv->zv_objset->os_sync == ZFS_SYNC_ALWAYS;
 
 	/*
 	 * There must be no buffer changes when doing a dmu_sync() because
@@ -1290,7 +1313,15 @@ zvol_strategy(struct bio *bp)
 
 	while (resid != 0 && off < volsize) {
 		size_t size = MIN(resid, zvol_maxphys);
+#ifdef illumos
+		if (is_dumpified) {
+			size = MIN(size, P2END(off, zv->zv_volblocksize) - off);
+			error = zvol_dumpio(zv, addr, off, size,
+			    doread, B_FALSE);
+		} else if (doread) {
+#else
 		if (doread) {
+#endif
 			error = dmu_read(os, ZVOL_OBJ, off, size, addr,
 			    DMU_READ_PREFETCH);
 		} else {
@@ -1824,21 +1855,67 @@ zvol_fini(void)
 }
 
 #ifdef sun
+/*ARGSUSED*/
+static int
+zfs_mvdev_dump_feature_check(void *arg, dmu_tx_t *tx)
+{
+	spa_t *spa = dmu_tx_pool(tx)->dp_spa;
+
+	if (spa_feature_is_active(spa,
+	    &spa_feature_table[SPA_FEATURE_MULTI_VDEV_CRASH_DUMP]))
+		return (1);
+	return (0);
+}
+
+/*ARGSUSED*/
+static void
+zfs_mvdev_dump_activate_feature_sync(void *arg, dmu_tx_t *tx)
+{
+	spa_t *spa = dmu_tx_pool(tx)->dp_spa;
+
+	spa_feature_incr(spa,
+	    &spa_feature_table[SPA_FEATURE_MULTI_VDEV_CRASH_DUMP], tx);
+}
+
 static int
 zvol_dump_init(zvol_state_t *zv, boolean_t resize)
 {
 	dmu_tx_t *tx;
-	int error = 0;
+	int error;
 	objset_t *os = zv->zv_objset;
+	spa_t *spa = dmu_objset_spa(os);
+	vdev_t *vd = spa->spa_root_vdev;
 	nvlist_t *nv = NULL;
-	uint64_t version = spa_version(dmu_objset_spa(zv->zv_objset));
+	uint64_t version = spa_version(spa);
+	enum zio_checksum checksum;
 
 	ASSERT(MUTEX_HELD(&spa_namespace_lock));
+	ASSERT(vd->vdev_ops == &vdev_root_ops);
+
 	error = dmu_free_long_range(zv->zv_objset, ZVOL_OBJ, 0,
 	    DMU_OBJECT_END);
 	/* wait for dmu_free_long_range to actually free the blocks */
 	txg_wait_synced(dmu_objset_pool(zv->zv_objset), 0);
 
+	/*
+	 * If the pool on which the dump device is being initialized has more
+	 * than one child vdev, check that the MULTI_VDEV_CRASH_DUMP feature is
+	 * enabled.  If so, bump that feature's counter to indicate that the
+	 * feature is active. We also check the vdev type to handle the
+	 * following case:
+	 *   # zpool create test raidz disk1 disk2 disk3
+	 *   Now have spa_root_vdev->vdev_children == 1 (the raidz vdev),
+	 *   the raidz vdev itself has 3 children.
+	 */
+	if (vd->vdev_children > 1 || vd->vdev_ops == &vdev_raidz_ops) {
+		if (!spa_feature_is_enabled(spa,
+		    &spa_feature_table[SPA_FEATURE_MULTI_VDEV_CRASH_DUMP]))
+			return (SET_ERROR(ENOTSUP));
+		(void) dsl_sync_task(spa_name(spa),
+		    zfs_mvdev_dump_feature_check,
+		    zfs_mvdev_dump_activate_feature_sync, NULL, 2);
+	}
+
 	tx = dmu_tx_create(os);
 	dmu_tx_hold_zap(tx, ZVOL_ZAP_OBJ, TRUE, NULL);
 	dmu_tx_hold_bonus(tx, ZVOL_OBJ);
@@ -1849,6 +1926,14 @@ zvol_dump_init(zvol_state_t *zv, boolean_t resize)
 	}
 
 	/*
+	 * If MULTI_VDEV_CRASH_DUMP is active, use the NOPARITY checksum
+	 * function.  Otherwise, use the old default -- OFF.
+	 */
+	checksum = spa_feature_is_active(spa,
+	    &spa_feature_table[SPA_FEATURE_MULTI_VDEV_CRASH_DUMP]) ?
+	    ZIO_CHECKSUM_NOPARITY : ZIO_CHECKSUM_OFF;
+
+	/*
 	 * If we are resizing the dump device then we only need to
 	 * update the refreservation to match the newly updated
 	 * zvolsize. Otherwise, we save off the original state of the
@@ -1911,7 +1996,7 @@ zvol_dump_init(zvol_state_t *zv, boolean_t resize)
 		    ZIO_COMPRESS_OFF) == 0);
 		VERIFY(nvlist_add_uint64(nv,
 		    zfs_prop_to_name(ZFS_PROP_CHECKSUM),
-		    ZIO_CHECKSUM_OFF) == 0);
+		    checksum) == 0);
 		if (version >= SPA_VERSION_DEDUP) {
 			VERIFY(nvlist_add_uint64(nv,
 			    zfs_prop_to_name(ZFS_PROP_DEDUP),