Update core ZFS code from build 121 to build 141.

1 files changed, 1886 insertions, 0 deletions

diff --git a/module/zfs/sa.c b/module/zfs/sa.c
new file mode 100644
index 000000000..a91b379f9
--- /dev/null
+++ b/module/zfs/sa.c
@@ -0,0 +1,1886 @@
+/*
+ * 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) 2010, Oracle and/or its affiliates. All rights reserved.
+ */
+
+#include <sys/zfs_context.h>
+#include <sys/types.h>
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/sysmacros.h>
+#include <sys/dmu.h>
+#include <sys/dmu_impl.h>
+#include <sys/dmu_objset.h>
+#include <sys/dbuf.h>
+#include <sys/dnode.h>
+#include <sys/zap.h>
+#include <sys/sa.h>
+#include <sys/sunddi.h>
+#include <sys/sa_impl.h>
+#include <sys/dnode.h>
+#include <sys/errno.h>
+#include <sys/zfs_context.h>
+
+/*
+ * ZFS System attributes:
+ *
+ * A generic mechanism to allow for arbitrary attributes
+ * to be stored in a dnode.  The data will be stored in the bonus buffer of
+ * the dnode and if necessary a special "spill" block will be used to handle
+ * overflow situations.  The spill block will be sized to fit the data
+ * from 512 - 128K.  When a spill block is used the BP (blkptr_t) for the
+ * spill block is stored at the end of the current bonus buffer.  Any
+ * attributes that would be in the way of the blkptr_t will be relocated
+ * into the spill block.
+ *
+ * Attribute registration:
+ *
+ * Stored persistently on a per dataset basis
+ * a mapping between attribute "string" names and their actual attribute
+ * numeric values, length, and byteswap function.  The names are only used
+ * during registration.  All  attributes are known by their unique attribute
+ * id value.  If an attribute can have a variable size then the value
+ * 0 will be used to indicate this.
+ *
+ * Attribute Layout:
+ *
+ * Attribute layouts are a way to compactly store multiple attributes, but
+ * without taking the overhead associated with managing each attribute
+ * individually.  Since you will typically have the same set of attributes
+ * stored in the same order a single table will be used to represent that
+ * layout.  The ZPL for example will usually have only about 10 different
+ * layouts (regular files, device files, symlinks,
+ * regular files + scanstamp, files/dir with extended attributes, and then
+ * you have the possibility of all of those minus ACL, because it would
+ * be kicked out into the spill block)
+ *
+ * Layouts are simply an array of the attributes and their
+ * ordering i.e. [0, 1, 4, 5, 2]
+ *
+ * Each distinct layout is given a unique layout number and that is whats
+ * stored in the header at the beginning of the SA data buffer.
+ *
+ * A layout only covers a single dbuf (bonus or spill).  If a set of
+ * attributes is split up between the bonus buffer and a spill buffer then
+ * two different layouts will be used.  This allows us to byteswap the
+ * spill without looking at the bonus buffer and keeps the on disk format of
+ * the bonus and spill buffer the same.
+ *
+ * Adding a single attribute will cause the entire set of attributes to
+ * be rewritten and could result in a new layout number being constructed
+ * as part of the rewrite if no such layout exists for the new set of
+ * attribues.  The new attribute will be appended to the end of the already
+ * existing attributes.
+ *
+ * Both the attribute registration and attribute layout information are
+ * stored in normal ZAP attributes.  Their should be a small number of
+ * known layouts and the set of attributes is assumed to typically be quite
+ * small.
+ *
+ * The registered attributes and layout "table" information is maintained
+ * in core and a special "sa_os_t" is attached to the objset_t.
+ *
+ * A special interface is provided to allow for quickly applying
+ * a large set of attributes at once.  sa_replace_all_by_template() is
+ * used to set an array of attributes.  This is used by the ZPL when
+ * creating a brand new file.  The template that is passed into the function
+ * specifies the attribute, size for variable length attributes, location of
+ * data and special "data locator" function if the data isn't in a contiguous
+ * location.
+ *
+ * Byteswap implications:
+ * Since the SA attributes are not entirely self describing we can't do
+ * the normal byteswap processing.  The special ZAP layout attribute and
+ * attribute registration attributes define the byteswap function and the
+ * size of the attributes, unless it is variable sized.
+ * The normal ZFS byteswapping infrastructure assumes you don't need
+ * to read any objects in order to do the necessary byteswapping.  Whereas
+ * SA attributes can only be properly byteswapped if the dataset is opened
+ * and the layout/attribute ZAP attributes are available.  Because of this
+ * the SA attributes will be byteswapped when they are first accessed by
+ * the SA code that will read the SA data.
+ */
+
+typedef void (sa_iterfunc_t)(void *hdr, void *addr, sa_attr_type_t,
+    uint16_t length, int length_idx, boolean_t, void *userp);
+
+static int sa_build_index(sa_handle_t *hdl, sa_buf_type_t buftype);
+static void sa_idx_tab_hold(objset_t *os, sa_idx_tab_t *idx_tab);
+static void *sa_find_idx_tab(objset_t *os, dmu_object_type_t bonustype,
+    void *data);
+static void sa_idx_tab_rele(objset_t *os, void *arg);
+static void sa_copy_data(sa_data_locator_t *func, void *start, void *target,
+    int buflen);
+static int sa_modify_attrs(sa_handle_t *hdl, sa_attr_type_t newattr,
+    sa_data_op_t action, sa_data_locator_t *locator, void *datastart,
+    uint16_t buflen, dmu_tx_t *tx);
+
+arc_byteswap_func_t *sa_bswap_table[] = {
+	byteswap_uint64_array,
+	byteswap_uint32_array,
+	byteswap_uint16_array,
+	byteswap_uint8_array,
+	zfs_acl_byteswap,
+};
+
+#define	SA_COPY_DATA(f, s, t, l) \
+	{ \
+		if (f == NULL) { \
+			if (l == 8) { \
+				*(uint64_t *)t = *(uint64_t *)s; \
+			} else if (l == 16) { \
+				*(uint64_t *)t = *(uint64_t *)s; \
+				*(uint64_t *)((uintptr_t)t + 8) = \
+				    *(uint64_t *)((uintptr_t)s + 8); \
+			} else { \
+				bcopy(s, t, l); \
+			} \
+		} else \
+			sa_copy_data(f, s, t, l); \
+	}
+
+/*
+ * This table is fixed and cannot be changed.  Its purpose is to
+ * allow the SA code to work with both old/new ZPL file systems.
+ * It contains the list of legacy attributes.  These attributes aren't
+ * stored in the "attribute" registry zap objects, since older ZPL file systems
+ * won't have the registry.  Only objsets of type ZFS_TYPE_FILESYSTEM will
+ * use this static table.
+ */
+sa_attr_reg_t sa_legacy_attrs[] = {
+	{"ZPL_ATIME", sizeof (uint64_t) * 2, SA_UINT64_ARRAY, 0},
+	{"ZPL_MTIME", sizeof (uint64_t) * 2, SA_UINT64_ARRAY, 1},
+	{"ZPL_CTIME", sizeof (uint64_t) * 2, SA_UINT64_ARRAY, 2},
+	{"ZPL_CRTIME", sizeof (uint64_t) * 2, SA_UINT64_ARRAY, 3},
+	{"ZPL_GEN", sizeof (uint64_t), SA_UINT64_ARRAY, 4},
+	{"ZPL_MODE", sizeof (uint64_t), SA_UINT64_ARRAY, 5},
+	{"ZPL_SIZE", sizeof (uint64_t), SA_UINT64_ARRAY, 6},
+	{"ZPL_PARENT", sizeof (uint64_t), SA_UINT64_ARRAY, 7},
+	{"ZPL_LINKS", sizeof (uint64_t), SA_UINT64_ARRAY, 8},
+	{"ZPL_XATTR", sizeof (uint64_t), SA_UINT64_ARRAY, 9},
+	{"ZPL_RDEV", sizeof (uint64_t), SA_UINT64_ARRAY, 10},
+	{"ZPL_FLAGS", sizeof (uint64_t), SA_UINT64_ARRAY, 11},
+	{"ZPL_UID", sizeof (uint64_t), SA_UINT64_ARRAY, 12},
+	{"ZPL_GID", sizeof (uint64_t), SA_UINT64_ARRAY, 13},
+	{"ZPL_PAD", sizeof (uint64_t) * 4, SA_UINT64_ARRAY, 14},
+	{"ZPL_ZNODE_ACL", 88, SA_UINT8_ARRAY, 15},
+};
+
+/*
+ * ZPL legacy layout
+ * This is only used for objects of type DMU_OT_ZNODE
+ */
+sa_attr_type_t sa_legacy_zpl_layout[] = {
+    0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15
+};
+
+/*
+ * Special dummy layout used for buffers with no attributes.
+ */
+
+sa_attr_type_t sa_dummy_zpl_layout[] = { 0 };
+
+static int sa_legacy_attr_count = 16;
+static kmem_cache_t *sa_cache = NULL;
+
+/*ARGSUSED*/
+static int
+sa_cache_constructor(void *buf, void *unused, int kmflag)
+{
+	sa_handle_t *hdl = buf;
+
+	hdl->sa_bonus_tab = NULL;
+	hdl->sa_spill_tab = NULL;
+	hdl->sa_os = NULL;
+	hdl->sa_userp = NULL;
+	hdl->sa_bonus = NULL;
+	hdl->sa_spill = NULL;
+	mutex_init(&hdl->sa_lock, NULL, MUTEX_DEFAULT, NULL);
+	return (0);
+}
+
+/*ARGSUSED*/
+static void
+sa_cache_destructor(void *buf, void *unused)
+{
+	sa_handle_t *hdl = buf;
+	mutex_destroy(&hdl->sa_lock);
+}
+
+void
+sa_cache_init(void)
+{
+	sa_cache = kmem_cache_create("sa_cache",
+	    sizeof (sa_handle_t), 0, sa_cache_constructor,
+	    sa_cache_destructor, NULL, NULL, NULL, 0);
+}
+
+void
+sa_cache_fini(void)
+{
+	if (sa_cache)
+		kmem_cache_destroy(sa_cache);
+}
+
+static int
+layout_num_compare(const void *arg1, const void *arg2)
+{
+	const sa_lot_t *node1 = arg1;
+	const sa_lot_t *node2 = arg2;
+
+	if (node1->lot_num > node2->lot_num)
+		return (1);
+	else if (node1->lot_num < node2->lot_num)
+		return (-1);
+	return (0);
+}
+
+static int
+layout_hash_compare(const void *arg1, const void *arg2)
+{
+	const sa_lot_t *node1 = arg1;
+	const sa_lot_t *node2 = arg2;
+
+	if (node1->lot_hash > node2->lot_hash)
+		return (1);
+	if (node1->lot_hash < node2->lot_hash)
+		return (-1);
+	if (node1->lot_instance > node2->lot_instance)
+		return (1);
+	if (node1->lot_instance < node2->lot_instance)
+		return (-1);
+	return (0);
+}
+
+boolean_t
+sa_layout_equal(sa_lot_t *tbf, sa_attr_type_t *attrs, int count)
+{
+	int i;
+
+	if (count != tbf->lot_attr_count)
+		return (1);
+
+	for (i = 0; i != count; i++) {
+		if (attrs[i] != tbf->lot_attrs[i])
+			return (1);
+	}
+	return (0);
+}
+
+#define	SA_ATTR_HASH(attr) (zfs_crc64_table[(-1ULL ^ attr) & 0xFF])
+
+static uint64_t
+sa_layout_info_hash(sa_attr_type_t *attrs, int attr_count)
+{
+	int i;
+	uint64_t crc = -1ULL;
+
+	for (i = 0; i != attr_count; i++)
+		crc ^= SA_ATTR_HASH(attrs[i]);
+
+	return (crc);
+}
+
+static boolean_t
+sa_has_blkptr(sa_handle_t *hdl)
+{
+	int rc;
+	if (hdl->sa_spill == NULL) {
+		if ((rc = dmu_spill_hold_existing(hdl->sa_bonus, NULL,
+		    &hdl->sa_spill)) == 0)
+			VERIFY(0 == sa_build_index(hdl, SA_SPILL));
+	} else {
+		rc = 0;
+	}
+
+	return (rc == 0 ? B_TRUE : B_FALSE);
+}
+
+/*
+ * Main attribute lookup/update function
+ * returns 0 for success or non zero for failures
+ *
+ * Operates on bulk array, first failure will abort further processing
+ */
+int
+sa_attr_op(sa_handle_t *hdl, sa_bulk_attr_t *bulk, int count,
+    sa_data_op_t data_op, dmu_tx_t *tx)
+{
+	sa_os_t *sa = hdl->sa_os->os_sa;
+	int i;
+	int error = 0;
+	sa_buf_type_t buftypes;
+
+	buftypes = 0;
+
+	ASSERT(count > 0);
+	for (i = 0; i != count; i++) {
+		ASSERT(bulk[i].sa_attr <= hdl->sa_os->os_sa->sa_num_attrs);
+
+		bulk[i].sa_addr = NULL;
+		/* First check the bonus buffer */
+
+		if (hdl->sa_bonus_tab && TOC_ATTR_PRESENT(
+		    hdl->sa_bonus_tab->sa_idx_tab[bulk[i].sa_attr])) {
+			SA_ATTR_INFO(sa, hdl->sa_bonus_tab,
+			    SA_GET_HDR(hdl, SA_BONUS),
+			    bulk[i].sa_attr, bulk[i], SA_BONUS, hdl);
+			if (tx && !(buftypes & SA_BONUS)) {
+				dmu_buf_will_dirty(hdl->sa_bonus, tx);
+				buftypes |= SA_BONUS;
+			}
+		}
+		if (bulk[i].sa_addr == NULL && sa_has_blkptr(hdl)) {
+			if (TOC_ATTR_PRESENT(
+			    hdl->sa_spill_tab->sa_idx_tab[bulk[i].sa_attr])) {
+				SA_ATTR_INFO(sa, hdl->sa_spill_tab,
+				    SA_GET_HDR(hdl, SA_SPILL),
+				    bulk[i].sa_attr, bulk[i], SA_SPILL, hdl);
+				if (tx && !(buftypes & SA_SPILL) &&
+				    bulk[i].sa_size == bulk[i].sa_length) {
+					dmu_buf_will_dirty(hdl->sa_spill, tx);
+					buftypes |= SA_SPILL;
+				}
+			}
+		}
+		switch (data_op) {
+		case SA_LOOKUP:
+			if (bulk[i].sa_addr == NULL)
+				return (ENOENT);
+			if (bulk[i].sa_data) {
+				SA_COPY_DATA(bulk[i].sa_data_func,
+				    bulk[i].sa_addr, bulk[i].sa_data,
+				    bulk[i].sa_size);
+			}
+			continue;
+
+		case SA_UPDATE:
+			/* existing rewrite of attr */
+			if (bulk[i].sa_addr &&
+			    bulk[i].sa_size == bulk[i].sa_length) {
+				SA_COPY_DATA(bulk[i].sa_data_func,
+				    bulk[i].sa_data, bulk[i].sa_addr,
+				    bulk[i].sa_length);
+				continue;
+			} else if (bulk[i].sa_addr) { /* attr size change */
+				error = sa_modify_attrs(hdl, bulk[i].sa_attr,
+				    SA_REPLACE, bulk[i].sa_data_func,
+				    bulk[i].sa_data, bulk[i].sa_length, tx);
+			} else { /* adding new attribute */
+				error = sa_modify_attrs(hdl, bulk[i].sa_attr,
+				    SA_ADD, bulk[i].sa_data_func,
+				    bulk[i].sa_data, bulk[i].sa_length, tx);
+			}
+			if (error)
+				return (error);
+			break;
+		}
+	}
+	return (error);
+}
+
+static sa_lot_t *
+sa_add_layout_entry(objset_t *os, sa_attr_type_t *attrs, int attr_count,
+    uint64_t lot_num, uint64_t hash, boolean_t zapadd, dmu_tx_t *tx)
+{
+	sa_os_t *sa = os->os_sa;
+	sa_lot_t *tb, *findtb;
+	int i;
+	avl_index_t loc;
+
+	ASSERT(MUTEX_HELD(&sa->sa_lock));
+	tb = kmem_zalloc(sizeof (sa_lot_t), KM_SLEEP);
+	tb->lot_attr_count = attr_count;
+	tb->lot_attrs = kmem_alloc(sizeof (sa_attr_type_t) * attr_count,
+	    KM_SLEEP);
+	bcopy(attrs, tb->lot_attrs, sizeof (sa_attr_type_t) * attr_count);
+	tb->lot_num = lot_num;
+	tb->lot_hash = hash;
+	tb->lot_instance = 0;
+
+	if (zapadd) {
+		char attr_name[8];
+
+		if (sa->sa_layout_attr_obj == 0) {
+			int error;
+			sa->sa_layout_attr_obj = zap_create(os,
+			    DMU_OT_SA_ATTR_LAYOUTS, DMU_OT_NONE, 0, tx);
+			error = zap_add(os, sa->sa_master_obj, SA_LAYOUTS, 8, 1,
+			    &sa->sa_layout_attr_obj, tx);
+			ASSERT3U(error, ==, 0);
+		}
+
+		(void) snprintf(attr_name, sizeof (attr_name),
+		    "%d", (int)lot_num);
+		VERIFY(0 == zap_update(os, os->os_sa->sa_layout_attr_obj,
+		    attr_name, 2, attr_count, attrs, tx));
+	}
+
+	list_create(&tb->lot_idx_tab, sizeof (sa_idx_tab_t),
+	    offsetof(sa_idx_tab_t, sa_next));
+
+	for (i = 0; i != attr_count; i++) {
+		if (sa->sa_attr_table[tb->lot_attrs[i]].sa_length == 0)
+			tb->lot_var_sizes++;
+	}
+
+	avl_add(&sa->sa_layout_num_tree, tb);
+
+	/* verify we don't have a hash collision */
+	if ((findtb = avl_find(&sa->sa_layout_hash_tree, tb, &loc)) != NULL) {
+		for (; findtb && findtb->lot_hash == hash;
+		    findtb = AVL_NEXT(&sa->sa_layout_hash_tree, findtb)) {
+			if (findtb->lot_instance != tb->lot_instance)
+				break;
+			tb->lot_instance++;
+		}
+	}
+	avl_add(&sa->sa_layout_hash_tree, tb);
+	return (tb);
+}
+
+static void
+sa_find_layout(objset_t *os, uint64_t hash, sa_attr_type_t *attrs,
+    int count, dmu_tx_t *tx, sa_lot_t **lot)
+{
+	sa_lot_t *tb, tbsearch;
+	avl_index_t loc;
+	sa_os_t *sa = os->os_sa;
+	boolean_t found = B_FALSE;
+
+	mutex_enter(&sa->sa_lock);
+	tbsearch.lot_hash = hash;
+	tbsearch.lot_instance = 0;
+	tb = avl_find(&sa->sa_layout_hash_tree, &tbsearch, &loc);
+	if (tb) {
+		for (; tb && tb->lot_hash == hash;
+		    tb = AVL_NEXT(&sa->sa_layout_hash_tree, tb)) {
+			if (sa_layout_equal(tb, attrs, count) == 0) {
+				found = B_TRUE;
+				break;
+			}
+		}
+	}
+	if (!found) {
+		tb = sa_add_layout_entry(os, attrs, count,
+		    avl_numnodes(&sa->sa_layout_num_tree), hash, B_TRUE, tx);
+	}
+	mutex_exit(&sa->sa_lock);
+	*lot = tb;
+}
+
+static int
+sa_resize_spill(sa_handle_t *hdl, uint32_t size, dmu_tx_t *tx)
+{
+	int error;
+	uint32_t blocksize;
+
+	if (size == 0) {
+		blocksize = SPA_MINBLOCKSIZE;
+	} else if (size > SPA_MAXBLOCKSIZE) {
+		ASSERT(0);
+		return (EFBIG);
+	} else {
+		blocksize = P2ROUNDUP_TYPED(size, SPA_MINBLOCKSIZE, uint32_t);
+	}
+
+	error = dbuf_spill_set_blksz(hdl->sa_spill, blocksize, tx);
+	ASSERT(error == 0);
+	return (error);
+}
+
+static void
+sa_copy_data(sa_data_locator_t *func, void *datastart, void *target, int buflen)
+{
+	if (func == NULL) {
+		bcopy(datastart, target, buflen);
+	} else {
+		boolean_t start;
+		int bytes;
+		void *dataptr;
+		void *saptr = target;
+		uint32_t length;
+
+		start = B_TRUE;
+		bytes = 0;
+		while (bytes < buflen) {
+			func(&dataptr, &length, buflen, start, datastart);
+			bcopy(dataptr, saptr, length);
+			saptr = (void *)((caddr_t)saptr + length);
+			bytes += length;
+			start = B_FALSE;
+		}
+	}
+}
+
+/*
+ * Determine several different sizes
+ * first the sa header size
+ * the number of bytes to be stored
+ * if spill would occur the index in the attribute array is returned
+ *
+ * the boolean will_spill will be set when spilling is necessary.  It
+ * is only set when the buftype is SA_BONUS
+ */
+static int
+sa_find_sizes(sa_os_t *sa, sa_bulk_attr_t *attr_desc, int attr_count,
+    dmu_buf_t *db, sa_buf_type_t buftype, int *index, int *total,
+    boolean_t *will_spill)
+{
+	int var_size = 0;
+	int i;
+	int full_space;
+	int hdrsize;
+	boolean_t done = B_FALSE;
+
+	if (buftype == SA_BONUS && sa->sa_force_spill) {
+		*total = 0;
+		*index = 0;
+		*will_spill = B_TRUE;
+		return (0);
+	}
+
+	*index = -1;
+	*total = 0;
+
+	if (buftype == SA_BONUS)
+		*will_spill = B_FALSE;
+
+	hdrsize = (SA_BONUSTYPE_FROM_DB(db) == DMU_OT_ZNODE) ? 0 :
+	    sizeof (sa_hdr_phys_t);
+
+	full_space = (buftype == SA_BONUS) ? DN_MAX_BONUSLEN : db->db_size;
+
+	for (i = 0; i != attr_count; i++) {
+		boolean_t is_var_sz;
+
+		*total += attr_desc[i].sa_length;
+		if (done)
+			goto next;
+
+		is_var_sz = (SA_REGISTERED_LEN(sa, attr_desc[i].sa_attr) == 0);
+		if (is_var_sz) {
+			var_size++;
+		}
+
+		if (is_var_sz && var_size > 1) {
+			if (P2ROUNDUP(hdrsize + sizeof (uint16_t), 8) +
+			    *total < full_space) {
+				hdrsize += sizeof (uint16_t);
+			} else {
+				done = B_TRUE;
+				*index = i;
+				if (buftype == SA_BONUS)
+					*will_spill = B_TRUE;
+				continue;
+			}
+		}
+
+		/*
+		 * find index of where spill *could* occur.
+		 * Then continue to count of remainder attribute
+		 * space.  The sum is used later for sizing bonus
+		 * and spill buffer.
+		 */
+		if (buftype == SA_BONUS && *index == -1 &&
+		    P2ROUNDUP(*total + hdrsize, 8) >
+		    (full_space - sizeof (blkptr_t))) {
+			*index = i;
+			done = B_TRUE;
+		}
+
+next:
+		if (P2ROUNDUP(*total + hdrsize, 8) > full_space &&
+		    buftype == SA_BONUS)
+			*will_spill = B_TRUE;
+	}
+
+	hdrsize = P2ROUNDUP(hdrsize, 8);
+	return (hdrsize);
+}
+
+#define	BUF_SPACE_NEEDED(total, header) (total + header)
+
+/*
+ * Find layout that corresponds to ordering of attributes
+ * If not found a new layout number is created and added to
+ * persistent layout tables.
+ */
+static int
+sa_build_layouts(sa_handle_t *hdl, sa_bulk_attr_t *attr_desc, int attr_count,
+    dmu_tx_t *tx)
+{
+	sa_os_t *sa = hdl->sa_os->os_sa;
+	uint64_t hash;
+	sa_buf_type_t buftype;
+	sa_hdr_phys_t *sahdr;
+	void *data_start;
+	int buf_space;
+	sa_attr_type_t *attrs, *attrs_start;
+	int i, lot_count;
+	int hdrsize, spillhdrsize;
+	int used;
+	dmu_object_type_t bonustype;
+	sa_lot_t *lot;
+	int len_idx;
+	int spill_used;
+	boolean_t spilling;
+
+	dmu_buf_will_dirty(hdl->sa_bonus, tx);
+	bonustype = SA_BONUSTYPE_FROM_DB(hdl->sa_bonus);
+
+	/* first determine bonus header size and sum of all attributes */
+	hdrsize = sa_find_sizes(sa, attr_desc, attr_count, hdl->sa_bonus,
+	    SA_BONUS, &i, &used, &spilling);
+
+	if (used > SPA_MAXBLOCKSIZE)
+		return (EFBIG);
+
+	VERIFY(0 == dmu_set_bonus(hdl->sa_bonus, spilling ?
+	    MIN(DN_MAX_BONUSLEN - sizeof (blkptr_t), used + hdrsize) :
+	    used + hdrsize, tx));
+
+	ASSERT((bonustype == DMU_OT_ZNODE && spilling == 0) ||
+	    bonustype == DMU_OT_SA);
+
+	/* setup and size spill buffer when needed */
+	if (spilling) {
+		boolean_t dummy;
+
+		if (hdl->sa_spill == NULL) {
+			int error;
+			error = dmu_spill_hold_by_bonus(hdl->sa_bonus, NULL,
+			    &hdl->sa_spill);
+			ASSERT3U(error, ==, 0);
+		}
+		dmu_buf_will_dirty(hdl->sa_spill, tx);
+
+		spillhdrsize = sa_find_sizes(sa, &attr_desc[i],
+		    attr_count - i, hdl->sa_spill, SA_SPILL, &i,
+		    &spill_used, &dummy);
+
+		if (spill_used > SPA_MAXBLOCKSIZE)
+			return (EFBIG);
+
+		buf_space = hdl->sa_spill->db_size - spillhdrsize;
+		if (BUF_SPACE_NEEDED(spill_used, spillhdrsize) >
+		    hdl->sa_spill->db_size)
+			VERIFY(0 == sa_resize_spill(hdl,
+			    BUF_SPACE_NEEDED(spill_used, spillhdrsize), tx));
+	}
+
+	/* setup starting pointers to lay down data */
+	data_start = (void *)((uintptr_t)hdl->sa_bonus->db_data + hdrsize);
+	sahdr = (sa_hdr_phys_t *)hdl->sa_bonus->db_data;
+	buftype = SA_BONUS;
+
+	if (spilling)
+		buf_space = (sa->sa_force_spill) ?
+		    0 : SA_BLKPTR_SPACE - hdrsize;
+	else
+		buf_space = hdl->sa_bonus->db_size - hdrsize;
+
+	attrs_start = attrs = kmem_alloc(sizeof (sa_attr_type_t) * attr_count,
+	    KM_SLEEP);
+	lot_count = 0;
+
+	for (i = 0, len_idx = 0, hash = -1ULL; i != attr_count; i++) {
+		uint16_t length;
+
+		attrs[i] = attr_desc[i].sa_attr;
+		length = SA_REGISTERED_LEN(sa, attrs[i]);
+		if (length == 0)
+			length = attr_desc[i].sa_length;
+
+		if (buf_space < length) {  /* switch to spill buffer */
+			ASSERT(bonustype != DMU_OT_ZNODE);
+			if (buftype == SA_BONUS && !sa->sa_force_spill) {
+				sa_find_layout(hdl->sa_os, hash, attrs_start,
+				    lot_count, tx, &lot);
+				SA_SET_HDR(sahdr, lot->lot_num, hdrsize);
+			}
+
+			buftype = SA_SPILL;
+			hash = -1ULL;
+			len_idx = 0;
+
+			sahdr = (sa_hdr_phys_t *)hdl->sa_spill->db_data;
+			sahdr->sa_magic = SA_MAGIC;
+			data_start = (void *)((uintptr_t)sahdr +
+			    spillhdrsize);
+			attrs_start = &attrs[i];
+			buf_space = hdl->sa_spill->db_size - spillhdrsize;
+			lot_count = 0;
+		}
+		hash ^= SA_ATTR_HASH(attrs[i]);
+		attr_desc[i].sa_addr = data_start;
+		attr_desc[i].sa_size = length;
+		SA_COPY_DATA(attr_desc[i].sa_data_func, attr_desc[i].sa_data,
+		    data_start, length);
+		if (sa->sa_attr_table[attrs[i]].sa_length == 0) {
+			sahdr->sa_lengths[len_idx++] = length;
+		}
+		data_start = (void *)P2ROUNDUP(((uintptr_t)data_start +
+		    length), 8);
+		buf_space -= P2ROUNDUP(length, 8);
+		lot_count++;
+	}
+
+	sa_find_layout(hdl->sa_os, hash, attrs_start, lot_count, tx, &lot);
+	if (bonustype == DMU_OT_SA) {
+		SA_SET_HDR(sahdr, lot->lot_num,
+		    buftype == SA_BONUS ? hdrsize : spillhdrsize);
+	}
+
+	kmem_free(attrs, sizeof (sa_attr_type_t) * attr_count);
+	if (hdl->sa_bonus_tab) {
+		sa_idx_tab_rele(hdl->sa_os, hdl->sa_bonus_tab);
+		hdl->sa_bonus_tab = NULL;
+	}
+	if (!sa->sa_force_spill)
+		VERIFY(0 == sa_build_index(hdl, SA_BONUS));
+	if (hdl->sa_spill) {
+		sa_idx_tab_rele(hdl->sa_os, hdl->sa_spill_tab);
+		if (!spilling) {
+			/*
+			 * remove spill block that is no longer needed.
+			 * set sa_spill_remove to prevent sa_attr_op
+			 * from trying to retrieve spill block before its
+			 * been removed.  The flag will be cleared if/when
+			 * the handle is destroyed recreated or
+			 * sa_build_layouts() needs to spill again.
+			 */
+			dmu_buf_rele(hdl->sa_spill, NULL);
+			hdl->sa_spill = NULL;
+			hdl->sa_spill_tab = NULL;
+			VERIFY(0 == dmu_rm_spill(hdl->sa_os,
+			    sa_handle_object(hdl), tx));
+		} else {
+			VERIFY(0 == sa_build_index(hdl, SA_SPILL));
+		}
+	}
+
+	return (0);
+}
+
+static void
+sa_attr_table_setup(objset_t *os, sa_attr_reg_t *reg_attrs, int count)
+{
+	sa_os_t *sa = os->os_sa;
+	uint64_t sa_attr_count = 0;
+	int error = 0;
+	uint64_t attr_value;
+	sa_attr_table_t *tb;
+	zap_cursor_t zc;
+	zap_attribute_t za;
+	int registered_count = 0;
+	int i;
+	dmu_objset_type_t ostype = dmu_objset_type(os);
+
+	sa->sa_user_table =
+	    kmem_zalloc(count * sizeof (sa_attr_type_t), KM_SLEEP);
+	sa->sa_user_table_sz = count * sizeof (sa_attr_type_t);
+
+	if (sa->sa_reg_attr_obj != 0)
+		VERIFY(zap_count(os, sa->sa_reg_attr_obj, &sa_attr_count) == 0);
+
+	if (ostype == DMU_OST_ZFS && sa_attr_count == 0)
+		sa_attr_count += sa_legacy_attr_count;
+
+	/* Allocate attribute numbers for attributes that aren't registered */
+	for (i = 0; i != count; i++) {
+		boolean_t found = B_FALSE;
+		int j;
+
+		if (ostype == DMU_OST_ZFS) {
+			for (j = 0; j != sa_legacy_attr_count; j++) {
+				if (strcmp(reg_attrs[i].sa_name,
+				    sa_legacy_attrs[j].sa_name) == 0) {
+					sa->sa_user_table[i] =
+					    sa_legacy_attrs[j].sa_attr;
+					found = B_TRUE;
+				}
+			}
+		}
+		if (found)
+			continue;
+
+		if (sa->sa_reg_attr_obj)
+			error = zap_lookup(os, sa->sa_reg_attr_obj,
+			    reg_attrs[i].sa_name, 8, 1, &attr_value);
+		else
+			error = ENOENT;
+		switch (error) {
+		default:
+		case ENOENT:
+			sa->sa_user_table[i] = (sa_attr_type_t)sa_attr_count;
+			sa_attr_count++;
+			break;
+		case 0:
+			sa->sa_user_table[i] = ATTR_NUM(attr_value);
+			break;
+		}
+	}
+
+	os->os_sa->sa_num_attrs = sa_attr_count;
+	tb = os->os_sa->sa_attr_table =
+	    kmem_zalloc(sizeof (sa_attr_table_t) * sa_attr_count, KM_SLEEP);
+
+	/*
+	 * Attribute table is constructed from requested attribute list,
+	 * previously foreign registered attributes, and also the legacy
+	 * ZPL set of attributes.
+	 */
+
+	if (sa->sa_reg_attr_obj) {
+		for (zap_cursor_init(&zc, os, sa->sa_reg_attr_obj);
+		    zap_cursor_retrieve(&zc, &za) == 0;
+		    zap_cursor_advance(&zc)) {
+			uint64_t value;
+			value  = za.za_first_integer;
+
+			registered_count++;
+			tb[ATTR_NUM(value)].sa_attr = ATTR_NUM(value);
+			tb[ATTR_NUM(value)].sa_length = ATTR_LENGTH(value);
+			tb[ATTR_NUM(value)].sa_byteswap = ATTR_BSWAP(value);
+			tb[ATTR_NUM(value)].sa_registered = B_TRUE;
+
+			if (tb[ATTR_NUM(value)].sa_name) {
+				continue;
+			}
+			tb[ATTR_NUM(value)].sa_name =
+			    kmem_zalloc(strlen(za.za_name) +1, KM_SLEEP);
+			(void) strlcpy(tb[ATTR_NUM(value)].sa_name, za.za_name,
+			    strlen(za.za_name) +1);
+		}
+		zap_cursor_fini(&zc);
+	}
+
+	if (ostype == DMU_OST_ZFS) {
+		for (i = 0; i != sa_legacy_attr_count; i++) {
+			if (tb[i].sa_name)
+				continue;
+			tb[i].sa_attr = sa_legacy_attrs[i].sa_attr;
+			tb[i].sa_length = sa_legacy_attrs[i].sa_length;
+			tb[i].sa_byteswap = sa_legacy_attrs[i].sa_byteswap;
+			tb[i].sa_registered = B_FALSE;
+			tb[i].sa_name =
+			    kmem_zalloc(strlen(sa_legacy_attrs[i].sa_name) +1,
+			    KM_SLEEP);
+			(void) strlcpy(tb[i].sa_name,
+			    sa_legacy_attrs[i].sa_name,
+			    strlen(sa_legacy_attrs[i].sa_name) + 1);
+		}
+	}
+
+	for (i = 0; i != count; i++) {
+		sa_attr_type_t attr_id;
+
+		attr_id = sa->sa_user_table[i];
+		if (tb[attr_id].sa_name)
+			continue;
+
+		tb[attr_id].sa_length = reg_attrs[i].sa_length;
+		tb[attr_id].sa_byteswap = reg_attrs[i].sa_byteswap;
+		tb[attr_id].sa_attr = attr_id;
+		tb[attr_id].sa_name =
+		    kmem_zalloc(strlen(reg_attrs[i].sa_name) + 1, KM_SLEEP);
+		(void) strlcpy(tb[attr_id].sa_name, reg_attrs[i].sa_name,
+		    strlen(reg_attrs[i].sa_name) + 1);
+	}
+
+	os->os_sa->sa_need_attr_registration =
+	    (sa_attr_count != registered_count);
+}
+
+sa_attr_type_t *
+sa_setup(objset_t *os, uint64_t sa_obj, sa_attr_reg_t *reg_attrs, int count)
+{
+	zap_cursor_t zc;
+	zap_attribute_t za;
+	sa_os_t *sa;
+	dmu_objset_type_t ostype = dmu_objset_type(os);
+	sa_attr_type_t *tb;
+
+	mutex_enter(&os->os_lock);
+	if (os->os_sa) {
+		mutex_enter(&os->os_sa->sa_lock);
+		mutex_exit(&os->os_lock);
+		tb = os->os_sa->sa_user_table;
+		mutex_exit(&os->os_sa->sa_lock);
+		return (tb);
+	}
+
+	sa = kmem_zalloc(sizeof (sa_os_t), KM_SLEEP);
+	mutex_init(&sa->sa_lock, NULL, MUTEX_DEFAULT, NULL);
+	sa->sa_master_obj = sa_obj;
+
+	mutex_enter(&sa->sa_lock);
+	mutex_exit(&os->os_lock);
+	avl_create(&sa->sa_layout_num_tree, layout_num_compare,
+	    sizeof (sa_lot_t), offsetof(sa_lot_t, lot_num_node));
+	avl_create(&sa->sa_layout_hash_tree, layout_hash_compare,
+	    sizeof (sa_lot_t), offsetof(sa_lot_t, lot_hash_node));
+
+	if (sa_obj) {
+		int error;
+		error = zap_lookup(os, sa_obj, SA_LAYOUTS,
+		    8, 1, &sa->sa_layout_attr_obj);
+		if (error != 0 && error != ENOENT) {
+			return (NULL);
+		}
+		error = zap_lookup(os, sa_obj, SA_REGISTRY,
+		    8, 1, &sa->sa_reg_attr_obj);
+		if (error != 0 && error != ENOENT) {
+			mutex_exit(&sa->sa_lock);
+			return (NULL);
+		}
+	}
+
+	os->os_sa = sa;
+	sa_attr_table_setup(os, reg_attrs, count);
+
+	if (sa->sa_layout_attr_obj != 0) {
+		for (zap_cursor_init(&zc, os, sa->sa_layout_attr_obj);
+		    zap_cursor_retrieve(&zc, &za) == 0;
+		    zap_cursor_advance(&zc)) {
+			sa_attr_type_t *lot_attrs;
+			uint64_t lot_num;
+
+			lot_attrs = kmem_zalloc(sizeof (sa_attr_type_t) *
+			    za.za_num_integers, KM_SLEEP);
+
+			VERIFY(zap_lookup(os, sa->sa_layout_attr_obj,
+			    za.za_name, 2, za.za_num_integers, lot_attrs) == 0);
+			VERIFY(ddi_strtoull(za.za_name, NULL, 10,
+			    (unsigned long long *)&lot_num) == 0);
+
+			(void) sa_add_layout_entry(os, lot_attrs,
+			    za.za_num_integers, lot_num,
+			    sa_layout_info_hash(lot_attrs,
+			    za.za_num_integers), B_FALSE, NULL);
+			kmem_free(lot_attrs, sizeof (sa_attr_type_t) *
+			    za.za_num_integers);
+		}
+		zap_cursor_fini(&zc);
+	}
+
+	/* Add special layout number for old ZNODES */
+	if (ostype == DMU_OST_ZFS) {
+		(void) sa_add_layout_entry(os, sa_legacy_zpl_layout,
+		    sa_legacy_attr_count, 0,
+		    sa_layout_info_hash(sa_legacy_zpl_layout,
+		    sa_legacy_attr_count), B_FALSE, NULL);
+
+		(void) sa_add_layout_entry(os, sa_dummy_zpl_layout, 0, 1,
+		    0, B_FALSE, NULL);
+	}
+	mutex_exit(&sa->sa_lock);
+	return (os->os_sa->sa_user_table);
+}
+
+void
+sa_tear_down(objset_t *os)
+{
+	sa_os_t *sa = os->os_sa;
+	sa_lot_t *layout;
+	void *cookie;
+	int i;
+
+	kmem_free(sa->sa_user_table, sa->sa_user_table_sz);
+
+	/* Free up attr table */
+
+	for (i = 0; i != sa->sa_num_attrs; i++) {
+		if (sa->sa_attr_table[i].sa_name)
+			kmem_free(sa->sa_attr_table[i].sa_name,
+			    strlen(sa->sa_attr_table[i].sa_name) + 1);
+	}
+
+	kmem_free(sa->sa_attr_table,
+	    sizeof (sa_attr_table_t) * sa->sa_num_attrs);
+
+	cookie = NULL;
+	while (layout = avl_destroy_nodes(&sa->sa_layout_hash_tree, &cookie)) {
+		sa_idx_tab_t *tab;
+		while (tab = list_head(&layout->lot_idx_tab)) {
+			ASSERT(refcount_count(&tab->sa_refcount));
+			sa_idx_tab_rele(os, tab);
+		}
+	}
+
+	cookie = NULL;
+	while (layout = avl_destroy_nodes(&sa->sa_layout_num_tree, &cookie)) {
+		kmem_free(layout->lot_attrs,
+		    sizeof (sa_attr_type_t) * layout->lot_attr_count);
+		kmem_free(layout, sizeof (sa_lot_t));
+	}
+
+	avl_destroy(&sa->sa_layout_hash_tree);
+	avl_destroy(&sa->sa_layout_num_tree);
+
+	kmem_free(sa, sizeof (sa_os_t));
+	os->os_sa = NULL;
+}
+
+void
+sa_build_idx_tab(void *hdr, void *attr_addr, sa_attr_type_t attr,
+    uint16_t length, int length_idx, boolean_t var_length, void *userp)
+{
+	sa_idx_tab_t *idx_tab = userp;
+
+	if (var_length) {
+		ASSERT(idx_tab->sa_variable_lengths);
+		idx_tab->sa_variable_lengths[length_idx] = length;
+	}
+	TOC_ATTR_ENCODE(idx_tab->sa_idx_tab[attr], length_idx,
+	    (uint32_t)((uintptr_t)attr_addr - (uintptr_t)hdr));
+}
+
+static void
+sa_attr_iter(objset_t *os, sa_hdr_phys_t *hdr, dmu_object_type_t type,
+    sa_iterfunc_t func, sa_lot_t *tab, void *userp)
+{
+	void *data_start;
+	sa_lot_t *tb = tab;
+	sa_lot_t search;
+	avl_index_t loc;
+	sa_os_t *sa = os->os_sa;
+	int i;
+	uint16_t *length_start = NULL;
+	uint8_t length_idx = 0;
+
+	if (tab == NULL) {
+		search.lot_num = SA_LAYOUT_NUM(hdr, type);
+		tb = avl_find(&sa->sa_layout_num_tree, &search, &loc);
+		ASSERT(tb);
+	}
+
+	if (IS_SA_BONUSTYPE(type)) {
+		data_start = (void *)P2ROUNDUP(((uintptr_t)hdr +
+		    offsetof(sa_hdr_phys_t, sa_lengths) +
+		    (sizeof (uint16_t) * tb->lot_var_sizes)), 8);
+		length_start = hdr->sa_lengths;
+	} else {
+		data_start = hdr;
+	}
+
+	for (i = 0; i != tb->lot_attr_count; i++) {
+		int attr_length, reg_length;
+		uint8_t idx_len;
+
+		reg_length = sa->sa_attr_table[tb->lot_attrs[i]].sa_length;
+		if (reg_length) {
+			attr_length = reg_length;
+			idx_len = 0;
+		} else {
+			attr_length = length_start[length_idx];
+			idx_len = length_idx++;
+		}
+
+		func(hdr, data_start, tb->lot_attrs[i], attr_length,
+		    idx_len, reg_length == 0 ? B_TRUE : B_FALSE, userp);
+
+		data_start = (void *)P2ROUNDUP(((uintptr_t)data_start +
+		    attr_length), 8);
+	}
+}
+
+/*ARGSUSED*/
+void
+sa_byteswap_cb(void *hdr, void *attr_addr, sa_attr_type_t attr,
+    uint16_t length, int length_idx, boolean_t variable_length, void *userp)
+{
+	sa_handle_t *hdl = userp;
+	sa_os_t *sa = hdl->sa_os->os_sa;
+
+	sa_bswap_table[sa->sa_attr_table[attr].sa_byteswap](attr_addr, length);
+}
+
+void
+sa_byteswap(sa_handle_t *hdl, sa_buf_type_t buftype)
+{
+	sa_hdr_phys_t *sa_hdr_phys = SA_GET_HDR(hdl, buftype);
+	dmu_buf_impl_t *db;
+	sa_os_t *sa = hdl->sa_os->os_sa;
+	int num_lengths = 1;
+	int i;
+
+	ASSERT(MUTEX_HELD(&sa->sa_lock));
+	if (sa_hdr_phys->sa_magic == SA_MAGIC)
+		return;
+
+	db = SA_GET_DB(hdl, buftype);
+
+	if (buftype == SA_SPILL) {
+		arc_release(db->db_buf, NULL);
+		arc_buf_thaw(db->db_buf);
+	}
+
+	sa_hdr_phys->sa_magic = BSWAP_32(sa_hdr_phys->sa_magic);
+	sa_hdr_phys->sa_layout_info = BSWAP_16(sa_hdr_phys->sa_layout_info);
+
+	/*
+	 * Determine number of variable lenghts in header
+	 * The standard 8 byte header has one for free and a
+	 * 16 byte header would have 4 + 1;
+	 */
+	if (SA_HDR_SIZE(sa_hdr_phys) > 8)
+		num_lengths += (SA_HDR_SIZE(sa_hdr_phys) - 8) >> 1;
+	for (i = 0; i != num_lengths; i++)
+		sa_hdr_phys->sa_lengths[i] =
+		    BSWAP_16(sa_hdr_phys->sa_lengths[i]);
+
+	sa_attr_iter(hdl->sa_os, sa_hdr_phys, DMU_OT_SA,
+	    sa_byteswap_cb, NULL, hdl);
+
+	if (buftype == SA_SPILL)
+		arc_buf_freeze(((dmu_buf_impl_t *)hdl->sa_spill)->db_buf);
+}
+
+static int
+sa_build_index(sa_handle_t *hdl, sa_buf_type_t buftype)
+{
+	sa_hdr_phys_t *sa_hdr_phys;
+	dmu_buf_impl_t *db = SA_GET_DB(hdl, buftype);
+	dmu_object_type_t bonustype = SA_BONUSTYPE_FROM_DB(db);
+	sa_os_t *sa = hdl->sa_os->os_sa;
+	sa_idx_tab_t *idx_tab;
+
+	sa_hdr_phys = SA_GET_HDR(hdl, buftype);
+
+	mutex_enter(&sa->sa_lock);
+
+	/* Do we need to byteswap? */
+
+	/* only check if not old znode */
+	if (IS_SA_BONUSTYPE(bonustype) && sa_hdr_phys->sa_magic != SA_MAGIC &&
+	    sa_hdr_phys->sa_magic != 0) {
+		VERIFY(BSWAP_32(sa_hdr_phys->sa_magic) == SA_MAGIC);
+		sa_byteswap(hdl, buftype);
+	}
+
+	idx_tab = sa_find_idx_tab(hdl->sa_os, bonustype, sa_hdr_phys);
+
+	if (buftype == SA_BONUS)
+		hdl->sa_bonus_tab = idx_tab;
+	else
+		hdl->sa_spill_tab = idx_tab;
+
+	mutex_exit(&sa->sa_lock);
+	return (0);
+}
+
+/*ARGSUSED*/
+void
+sa_evict(dmu_buf_t *db, void *sap)
+{
+	panic("evicting sa dbuf %p\n", (void *)db);
+}
+
+static void
+sa_idx_tab_rele(objset_t *os, void *arg)
+{
+	sa_os_t *sa = os->os_sa;
+	sa_idx_tab_t *idx_tab = arg;
+
+	if (idx_tab == NULL)
+		return;
+
+	mutex_enter(&sa->sa_lock);
+	if (refcount_remove(&idx_tab->sa_refcount, NULL) == 0) {
+		list_remove(&idx_tab->sa_layout->lot_idx_tab, idx_tab);
+		if (idx_tab->sa_variable_lengths)
+			kmem_free(idx_tab->sa_variable_lengths,
+			    sizeof (uint16_t) *
+			    idx_tab->sa_layout->lot_var_sizes);
+		refcount_destroy(&idx_tab->sa_refcount);
+		kmem_free(idx_tab->sa_idx_tab,
+		    sizeof (uint32_t) * sa->sa_num_attrs);
+		kmem_free(idx_tab, sizeof (sa_idx_tab_t));
+	}
+	mutex_exit(&sa->sa_lock);
+}
+
+static void
+sa_idx_tab_hold(objset_t *os, sa_idx_tab_t *idx_tab)
+{
+	sa_os_t *sa = os->os_sa;
+
+	ASSERT(MUTEX_HELD(&sa->sa_lock));
+	(void) refcount_add(&idx_tab->sa_refcount, NULL);
+}
+
+void
+sa_handle_destroy(sa_handle_t *hdl)
+{
+	mutex_enter(&hdl->sa_lock);
+	(void) dmu_buf_update_user((dmu_buf_t *)hdl->sa_bonus, hdl,
+	    NULL, NULL, NULL);
+
+	if (hdl->sa_bonus_tab) {
+		sa_idx_tab_rele(hdl->sa_os, hdl->sa_bonus_tab);
+		hdl->sa_bonus_tab = NULL;
+	}
+	if (hdl->sa_spill_tab) {
+		sa_idx_tab_rele(hdl->sa_os, hdl->sa_spill_tab);
+		hdl->sa_spill_tab = NULL;
+	}
+
+	dmu_buf_rele(hdl->sa_bonus, NULL);
+
+	if (hdl->sa_spill)
+		dmu_buf_rele((dmu_buf_t *)hdl->sa_spill, NULL);
+	mutex_exit(&hdl->sa_lock);
+
+	kmem_cache_free(sa_cache, hdl);
+}
+
+int
+sa_handle_get_from_db(objset_t *os, dmu_buf_t *db, void *userp,
+    sa_handle_type_t hdl_type, sa_handle_t **handlepp)
+{
+	int error = 0;
+	dmu_object_info_t doi;
+	sa_handle_t *handle;
+
+#ifdef ZFS_DEBUG
+	dmu_object_info_from_db(db, &doi);
+	ASSERT(doi.doi_bonus_type == DMU_OT_SA ||
+	    doi.doi_bonus_type == DMU_OT_ZNODE);
+#endif
+	/* find handle, if it exists */
+	/* if one doesn't exist then create a new one, and initialize it */
+
+	handle = (hdl_type == SA_HDL_SHARED) ? dmu_buf_get_user(db) : NULL;
+	if (handle == NULL) {
+		sa_handle_t *newhandle;
+		handle = kmem_cache_alloc(sa_cache, KM_SLEEP);
+		handle->sa_userp = userp;
+		handle->sa_bonus = db;
+		handle->sa_os = os;
+		handle->sa_spill = NULL;
+
+		error = sa_build_index(handle, SA_BONUS);
+		newhandle = (hdl_type == SA_HDL_SHARED) ?
+		    dmu_buf_set_user_ie(db, handle,
+		    NULL, sa_evict) : NULL;
+
+		if (newhandle != NULL) {
+			kmem_cache_free(sa_cache, handle);
+			handle = newhandle;
+		}
+	}
+	*handlepp = handle;
+
+	return (error);
+}
+
+int
+sa_handle_get(objset_t *objset, uint64_t objid, void *userp,
+    sa_handle_type_t hdl_type, sa_handle_t **handlepp)
+{
+	dmu_buf_t *db;
+	int error;
+
+	if (error = dmu_bonus_hold(objset, objid, NULL, &db))
+		return (error);
+
+	return (sa_handle_get_from_db(objset, db, userp, hdl_type,
+	    handlepp));
+}
+
+int
+sa_buf_hold(objset_t *objset, uint64_t obj_num, void *tag, dmu_buf_t **db)
+{
+	return (dmu_bonus_hold(objset, obj_num, tag, db));
+}
+
+void
+sa_buf_rele(dmu_buf_t *db, void *tag)
+{
+	dmu_buf_rele(db, tag);
+}
+
+int
+sa_lookup_impl(sa_handle_t *hdl, sa_bulk_attr_t *bulk, int count)
+{
+	ASSERT(hdl);
+	ASSERT(MUTEX_HELD(&hdl->sa_lock));
+	return (sa_attr_op(hdl, bulk, count, SA_LOOKUP, NULL));
+}
+
+int
+sa_lookup(sa_handle_t *hdl, sa_attr_type_t attr, void *buf, uint32_t buflen)
+{
+	int error;
+	sa_bulk_attr_t bulk;
+
+	bulk.sa_attr = attr;
+	bulk.sa_data = buf;
+	bulk.sa_length = buflen;
+	bulk.sa_data_func = NULL;
+
+	ASSERT(hdl);
+	mutex_enter(&hdl->sa_lock);
+	error = sa_lookup_impl(hdl, &bulk, 1);
+	mutex_exit(&hdl->sa_lock);
+	return (error);
+}
+
+#ifdef _KERNEL
+int
+sa_lookup_uio(sa_handle_t *hdl, sa_attr_type_t attr, uio_t *uio)
+{
+	int error;
+	sa_bulk_attr_t bulk;
+
+	bulk.sa_data = NULL;
+	bulk.sa_attr = attr;
+	bulk.sa_data_func = NULL;
+
+	ASSERT(hdl);
+
+	mutex_enter(&hdl->sa_lock);
+	if (sa_attr_op(hdl, &bulk, 1, SA_LOOKUP, NULL) == 0) {
+		error = uiomove((void *)bulk.sa_addr, MIN(bulk.sa_size,
+		    uio->uio_resid), UIO_READ, uio);
+	} else {
+		error = ENOENT;
+	}
+	mutex_exit(&hdl->sa_lock);
+	return (error);
+
+}
+#endif
+
+/*
+ * Find an already existing TOC from given os and data
+ * This is a special interface to be used by the ZPL for
+ * finding the uid/gid/gen attributes.
+ */
+void *
+sa_find_idx_tab(objset_t *os, dmu_object_type_t bonustype, void *data)
+{
+	sa_idx_tab_t *idx_tab;
+	sa_hdr_phys_t *hdr = (sa_hdr_phys_t *)data;
+	sa_os_t *sa = os->os_sa;
+	sa_lot_t *tb, search;
+	avl_index_t loc;
+
+	/*
+	 * Deterimine layout number.  If SA node and header == 0 then
+	 * force the index table to the dummy "1" empty layout.
+	 *
+	 * The layout number would only be zero for a newly created file
+	 * that has not added any attributes yet, or with crypto enabled which
+	 * doesn't write any attributes to the bonus buffer.
+	 */
+
+	search.lot_num = SA_LAYOUT_NUM(hdr, bonustype);
+
+	tb = avl_find(&sa->sa_layout_num_tree, &search, &loc);
+
+	/* Verify header size is consistent with layout information */
+	ASSERT(tb);
+	ASSERT(IS_SA_BONUSTYPE(bonustype) &&
+	    SA_HDR_SIZE_MATCH_LAYOUT(hdr, tb) || !IS_SA_BONUSTYPE(bonustype) ||
+	    (IS_SA_BONUSTYPE(bonustype) && hdr->sa_layout_info == 0));
+
+	/*
+	 * See if any of the already existing TOC entries can be reused?
+	 */
+
+	for (idx_tab = list_head(&tb->lot_idx_tab); idx_tab;
+	    idx_tab = list_next(&tb->lot_idx_tab, idx_tab)) {
+		boolean_t valid_idx = B_TRUE;
+		int i;
+
+		if (tb->lot_var_sizes != 0 &&
+		    idx_tab->sa_variable_lengths != NULL) {
+			for (i = 0; i != tb->lot_var_sizes; i++) {
+				if (hdr->sa_lengths[i] !=
+				    idx_tab->sa_variable_lengths[i]) {
+					valid_idx = B_FALSE;
+					break;
+				}
+			}
+		}
+		if (valid_idx) {
+			sa_idx_tab_hold(os, idx_tab);
+			return (idx_tab);
+		}
+	}
+
+	/* No such luck, create a new entry */
+	idx_tab = kmem_zalloc(sizeof (sa_idx_tab_t), KM_SLEEP);
+	idx_tab->sa_idx_tab =
+	    kmem_zalloc(sizeof (uint32_t) * sa->sa_num_attrs, KM_SLEEP);
+	idx_tab->sa_layout = tb;
+	refcount_create(&idx_tab->sa_refcount);
+	if (tb->lot_var_sizes)
+		idx_tab->sa_variable_lengths = kmem_alloc(sizeof (uint16_t) *
+		    tb->lot_var_sizes, KM_SLEEP);
+
+	sa_attr_iter(os, hdr, bonustype, sa_build_idx_tab,
+	    tb, idx_tab);
+	sa_idx_tab_hold(os, idx_tab);   /* one hold for consumer */
+	sa_idx_tab_hold(os, idx_tab);	/* one for layout */
+	list_insert_tail(&tb->lot_idx_tab, idx_tab);
+	return (idx_tab);
+}
+
+void
+sa_default_locator(void **dataptr, uint32_t *len, uint32_t total_len,
+    boolean_t start, void *userdata)
+{
+	ASSERT(start);
+
+	*dataptr = userdata;
+	*len = total_len;
+}
+
+static void
+sa_attr_register_sync(sa_handle_t *hdl, dmu_tx_t *tx)
+{
+	uint64_t attr_value = 0;
+	sa_os_t *sa = hdl->sa_os->os_sa;
+	sa_attr_table_t *tb = sa->sa_attr_table;
+	int i;
+
+	mutex_enter(&sa->sa_lock);
+
+	if (!sa->sa_need_attr_registration || sa->sa_master_obj == NULL) {
+		mutex_exit(&sa->sa_lock);
+		return;
+	}
+
+	if (sa->sa_reg_attr_obj == NULL) {
+		int error;
+		sa->sa_reg_attr_obj = zap_create(hdl->sa_os,
+		    DMU_OT_SA_ATTR_REGISTRATION, DMU_OT_NONE, 0, tx);
+		error = zap_add(hdl->sa_os, sa->sa_master_obj,
+		    SA_REGISTRY, 8, 1, &sa->sa_reg_attr_obj, tx);
+		ASSERT(error == 0);
+	}
+	for (i = 0; i != sa->sa_num_attrs; i++) {
+		if (sa->sa_attr_table[i].sa_registered)
+			continue;
+		ATTR_ENCODE(attr_value, tb[i].sa_attr, tb[i].sa_length,
+		    tb[i].sa_byteswap);
+		VERIFY(0 == zap_update(hdl->sa_os, sa->sa_reg_attr_obj,
+		    tb[i].sa_name, 8, 1, &attr_value, tx));
+		tb[i].sa_registered = B_TRUE;
+	}
+	sa->sa_need_attr_registration = B_FALSE;
+	mutex_exit(&sa->sa_lock);
+}
+
+/*
+ * Replace all attributes with attributes specified in template.
+ * If dnode had a spill buffer then those attributes will be
+ * also be replaced, possibly with just an empty spill block
+ *
+ * This interface is intended to only be used for bulk adding of
+ * attributes for a new file.  It will also be used by the ZPL
+ * when converting and old formatted znode to native SA support.
+ */
+int
+sa_replace_all_by_template_locked(sa_handle_t *hdl, sa_bulk_attr_t *attr_desc,
+    int attr_count, dmu_tx_t *tx)
+{
+	sa_os_t *sa = hdl->sa_os->os_sa;
+
+	if (sa->sa_need_attr_registration)
+		sa_attr_register_sync(hdl, tx);
+	return (sa_build_layouts(hdl, attr_desc, attr_count, tx));
+}
+
+int
+sa_replace_all_by_template(sa_handle_t *hdl, sa_bulk_attr_t *attr_desc,
+    int attr_count, dmu_tx_t *tx)
+{
+	int error;
+
+	mutex_enter(&hdl->sa_lock);
+	error = sa_replace_all_by_template_locked(hdl, attr_desc,
+	    attr_count, tx);
+	mutex_exit(&hdl->sa_lock);
+	return (error);
+}
+
+/*
+ * add/remove/replace a single attribute and then rewrite the entire set
+ * of attributes.
+ */
+static int
+sa_modify_attrs(sa_handle_t *hdl, sa_attr_type_t newattr,
+    sa_data_op_t action, sa_data_locator_t *locator, void *datastart,
+    uint16_t buflen, dmu_tx_t *tx)
+{
+	sa_os_t *sa = hdl->sa_os->os_sa;
+	sa_bulk_attr_t *attr_desc;
+	void *old_data[2];
+	int bonus_attr_count = 0;
+	int bonus_data_size, spill_data_size;
+	int spill_attr_count = 0;
+	int error;
+	uint16_t length;
+	int i, j, k, length_idx;
+	sa_hdr_phys_t *hdr;
+	sa_idx_tab_t *idx_tab;
+	int attr_count;
+	int count;
+
+	ASSERT(MUTEX_HELD(&hdl->sa_lock));
+
+	/* First make of copy of the old data */
+
+	if (((dmu_buf_impl_t *)hdl->sa_bonus)->db_dnode->dn_bonuslen) {
+		bonus_data_size = hdl->sa_bonus->db_size;
+		old_data[0] = kmem_alloc(bonus_data_size, KM_SLEEP);
+		bcopy(hdl->sa_bonus->db_data, old_data[0],
+		    hdl->sa_bonus->db_size);
+		bonus_attr_count = hdl->sa_bonus_tab->sa_layout->lot_attr_count;
+	} else {
+		old_data[0] = NULL;
+	}
+
+	/* Bring spill buffer online if it isn't currently */
+
+	if (sa_has_blkptr(hdl)) {
+		spill_data_size = hdl->sa_spill->db_size;
+		old_data[1] = kmem_alloc(spill_data_size, KM_SLEEP);
+		bcopy(hdl->sa_spill->db_data, old_data[1],
+		    hdl->sa_spill->db_size);
+		spill_attr_count =
+		    hdl->sa_spill_tab->sa_layout->lot_attr_count;
+	} else {
+		old_data[1] = NULL;
+	}
+
+	/* build descriptor of all attributes */
+
+	attr_count = bonus_attr_count + spill_attr_count;
+	if (action == SA_ADD)
+		attr_count++;
+	else if (action == SA_REMOVE)
+		attr_count--;
+
+	attr_desc = kmem_zalloc(sizeof (sa_bulk_attr_t) * attr_count, KM_SLEEP);
+
+	/*
+	 * loop through bonus and spill buffer if it exists, and
+	 * build up new attr_descriptor to reset the attributes
+	 */
+	k = j = 0;
+	count = bonus_attr_count;
+	hdr = SA_GET_HDR(hdl, SA_BONUS);
+	idx_tab = SA_IDX_TAB_GET(hdl, SA_BONUS);
+	for (; k != 2; k++) {
+		/* iterate over each attribute in layout */
+		for (i = 0, length_idx = 0; i != count; i++) {
+			sa_attr_type_t attr;
+
+			attr = idx_tab->sa_layout->lot_attrs[i];
+			if (attr == newattr) {
+				if (action == SA_REMOVE) {
+					j++;
+					continue;
+				}
+				ASSERT(SA_REGISTERED_LEN(sa, attr) == 0);
+				ASSERT(action == SA_REPLACE);
+				SA_ADD_BULK_ATTR(attr_desc, j, attr,
+				    locator, datastart, buflen);
+			} else {
+				length = SA_REGISTERED_LEN(sa, attr);
+				if (length == 0) {
+					length = hdr->sa_lengths[length_idx++];
+				}
+
+				SA_ADD_BULK_ATTR(attr_desc, j, attr,
+				    NULL, (void *)
+				    (TOC_OFF(idx_tab->sa_idx_tab[attr]) +
+				    (uintptr_t)old_data[k]), length);
+			}
+		}
+		if (k == 0 && hdl->sa_spill) {
+			hdr = SA_GET_HDR(hdl, SA_SPILL);
+			idx_tab = SA_IDX_TAB_GET(hdl, SA_SPILL);
+			count = spill_attr_count;
+		} else {
+			break;
+		}
+	}
+	if (action == SA_ADD) {
+		length = SA_REGISTERED_LEN(sa, newattr);
+		if (length == 0) {
+			length = buflen;
+		}
+		SA_ADD_BULK_ATTR(attr_desc, j, newattr, locator,
+		    datastart, buflen);
+	}
+
+	error = sa_build_layouts(hdl, attr_desc, attr_count, tx);
+
+	if (old_data[0])
+		kmem_free(old_data[0], bonus_data_size);
+	if (old_data[1])
+		kmem_free(old_data[1], spill_data_size);
+	kmem_free(attr_desc, sizeof (sa_bulk_attr_t) * attr_count);
+
+	return (error);
+}
+
+static int
+sa_bulk_update_impl(sa_handle_t *hdl, sa_bulk_attr_t *bulk, int count,
+    dmu_tx_t *tx)
+{
+	int error;
+	sa_os_t *sa = hdl->sa_os->os_sa;
+	dmu_object_type_t bonustype;
+
+	bonustype = SA_BONUSTYPE_FROM_DB(SA_GET_DB(hdl, SA_BONUS));
+
+	ASSERT(hdl);
+	ASSERT(MUTEX_HELD(&hdl->sa_lock));
+
+	/* sync out registration table if necessary */
+	if (sa->sa_need_attr_registration)
+		sa_attr_register_sync(hdl, tx);
+
+	error = sa_attr_op(hdl, bulk, count, SA_UPDATE, tx);
+	if (error == 0 && !IS_SA_BONUSTYPE(bonustype) && sa->sa_update_cb)
+		sa->sa_update_cb(hdl, tx);
+
+	return (error);
+}
+
+/*
+ * update or add new attribute
+ */
+int
+sa_update(sa_handle_t *hdl, sa_attr_type_t type,
+    void *buf, uint32_t buflen, dmu_tx_t *tx)
+{
+	int error;
+	sa_bulk_attr_t bulk;
+
+	bulk.sa_attr = type;
+	bulk.sa_data_func = NULL;
+	bulk.sa_length = buflen;
+	bulk.sa_data = buf;
+
+	mutex_enter(&hdl->sa_lock);
+	error = sa_bulk_update_impl(hdl, &bulk, 1, tx);
+	mutex_exit(&hdl->sa_lock);
+	return (error);
+}
+
+int
+sa_update_from_cb(sa_handle_t *hdl, sa_attr_type_t attr,
+    uint32_t buflen, sa_data_locator_t *locator, void *userdata, dmu_tx_t *tx)
+{
+	int error;
+	sa_bulk_attr_t bulk;
+
+	bulk.sa_attr = attr;
+	bulk.sa_data = userdata;
+	bulk.sa_data_func = locator;
+	bulk.sa_length = buflen;
+
+	mutex_enter(&hdl->sa_lock);
+	error = sa_bulk_update_impl(hdl, &bulk, 1, tx);
+	mutex_exit(&hdl->sa_lock);
+	return (error);
+}
+
+/*
+ * Return size of an attribute
+ */
+
+int
+sa_size(sa_handle_t *hdl, sa_attr_type_t attr, int *size)
+{
+	sa_bulk_attr_t bulk;
+
+	bulk.sa_data = NULL;
+	bulk.sa_attr = attr;
+	bulk.sa_data_func = NULL;
+
+	ASSERT(hdl);
+	mutex_enter(&hdl->sa_lock);
+	if (sa_attr_op(hdl, &bulk, 1, SA_LOOKUP, NULL)) {
+		mutex_exit(&hdl->sa_lock);
+		return (ENOENT);
+	}
+	*size = bulk.sa_size;
+
+	mutex_exit(&hdl->sa_lock);
+	return (0);
+}
+
+int
+sa_bulk_lookup_locked(sa_handle_t *hdl, sa_bulk_attr_t *attrs, int count)
+{
+	ASSERT(hdl);
+	ASSERT(MUTEX_HELD(&hdl->sa_lock));
+	return (sa_lookup_impl(hdl, attrs, count));
+}
+
+int
+sa_bulk_lookup(sa_handle_t *hdl, sa_bulk_attr_t *attrs, int count)
+{
+	int error;
+
+	ASSERT(hdl);
+	mutex_enter(&hdl->sa_lock);
+	error = sa_bulk_lookup_locked(hdl, attrs, count);
+	mutex_exit(&hdl->sa_lock);
+	return (error);
+}
+
+int
+sa_bulk_update(sa_handle_t *hdl, sa_bulk_attr_t *attrs, int count, dmu_tx_t *tx)
+{
+	int error;
+
+	ASSERT(hdl);
+	mutex_enter(&hdl->sa_lock);
+	error = sa_bulk_update_impl(hdl, attrs, count, tx);
+	mutex_exit(&hdl->sa_lock);
+	return (error);
+}
+
+int
+sa_remove(sa_handle_t *hdl, sa_attr_type_t attr, dmu_tx_t *tx)
+{
+	int error;
+
+	mutex_enter(&hdl->sa_lock);
+	error = sa_modify_attrs(hdl, attr, SA_REMOVE, NULL,
+	    NULL, 0, tx);
+	mutex_exit(&hdl->sa_lock);
+	return (error);
+}
+
+void
+sa_object_info(sa_handle_t *hdl, dmu_object_info_t *doi)
+{
+	dmu_object_info_from_db((dmu_buf_t *)hdl->sa_bonus, doi);
+}
+
+void
+sa_object_size(sa_handle_t *hdl, uint32_t *blksize, u_longlong_t *nblocks)
+{
+	dmu_object_size_from_db((dmu_buf_t *)hdl->sa_bonus,
+	    blksize, nblocks);
+}
+
+void
+sa_update_user(sa_handle_t *newhdl, sa_handle_t *oldhdl)
+{
+	(void) dmu_buf_update_user((dmu_buf_t *)newhdl->sa_bonus,
+	    oldhdl, newhdl, NULL, sa_evict);
+	oldhdl->sa_bonus = NULL;
+}
+
+void
+sa_set_userp(sa_handle_t *hdl, void *ptr)
+{
+	hdl->sa_userp = ptr;
+}
+
+dmu_buf_t *
+sa_get_db(sa_handle_t *hdl)
+{
+	return ((dmu_buf_t *)hdl->sa_bonus);
+}
+
+void *
+sa_get_userdata(sa_handle_t *hdl)
+{
+	return (hdl->sa_userp);
+}
+
+void
+sa_register_update_callback_locked(objset_t *os, sa_update_cb_t *func)
+{
+	ASSERT(MUTEX_HELD(&os->os_sa->sa_lock));
+	os->os_sa->sa_update_cb = func;
+}
+
+void
+sa_register_update_callback(objset_t *os, sa_update_cb_t *func)
+{
+
+	mutex_enter(&os->os_sa->sa_lock);
+	sa_register_update_callback_locked(os, func);
+	mutex_exit(&os->os_sa->sa_lock);
+}
+
+uint64_t
+sa_handle_object(sa_handle_t *hdl)
+{
+	return (hdl->sa_bonus->db_object);
+}
+
+boolean_t
+sa_enabled(objset_t *os)
+{
+	return (os->os_sa == NULL);
+}
+
+int
+sa_set_sa_object(objset_t *os, uint64_t sa_object)
+{
+	sa_os_t *sa = os->os_sa;
+
+	if (sa->sa_master_obj)
+		return (1);
+
+	sa->sa_master_obj = sa_object;
+
+	return (0);
+}
+
+int
+sa_hdrsize(void *arg)
+{
+	sa_hdr_phys_t *hdr = arg;
+
+	return (SA_HDR_SIZE(hdr));
+}
+
+void
+sa_handle_lock(sa_handle_t *hdl)
+{
+	ASSERT(hdl);
+	mutex_enter(&hdl->sa_lock);
+}
+
+void
+sa_handle_unlock(sa_handle_t *hdl)
+{
+	ASSERT(hdl);
+	mutex_exit(&hdl->sa_lock);
+}