zfs/include/sys/sa_impl.h

/*
 * 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.
 */

#ifndef	_SYS_SA_IMPL_H
#define	_SYS_SA_IMPL_H

#include <sys/dmu.h>
#include <sys/refcount.h>
#include <sys/list.h>

/*
 * Array of known attributes and their
 * various characteristics.
 */
typedef struct sa_attr_table {
	sa_attr_type_t	sa_attr;
	uint8_t sa_registered;
	uint16_t sa_length;
	sa_bswap_type_t sa_byteswap;
	char *sa_name;
} sa_attr_table_t;

/*
 * Zap attribute format for attribute registration
 *
 * 64      56      48      40      32      24      16      8       0
 * +-------+-------+-------+-------+-------+-------+-------+-------+
 * |        unused         |      len      | bswap |   attr num    |
 * +-------+-------+-------+-------+-------+-------+-------+-------+
 *
 * Zap attribute format for layout information.
 *
 * layout information is stored as an array of attribute numbers
 * The name of the attribute is the layout number (0, 1, 2, ...)
 *
 * 16       0
 * +---- ---+
 * | attr # |
 * +--------+
 * | attr # |
 * +--- ----+
 *  ......
 *
 */

#define	ATTR_BSWAP(x)	BF32_GET(x, 16, 8)
#define	ATTR_LENGTH(x)	BF32_GET(x, 24, 16)
#define	ATTR_NUM(x)	BF32_GET(x, 0, 16)
#define	ATTR_ENCODE(x, attr, length, bswap) \
{ \
	BF64_SET(x, 24, 16, length); \
	BF64_SET(x, 16, 8, bswap); \
	BF64_SET(x, 0, 16, attr); \
}

#define	TOC_OFF(x)		BF32_GET(x, 0, 23)
#define	TOC_ATTR_PRESENT(x)	BF32_GET(x, 31, 1)
#define	TOC_LEN_IDX(x)		BF32_GET(x, 24, 4)
#define	TOC_ATTR_ENCODE(x, len_idx, offset) \
{ \
	BF32_SET(x, 31, 1, 1); \
	BF32_SET(x, 24, 7, len_idx); \
	BF32_SET(x, 0, 24, offset); \
}

#define	SA_LAYOUTS	"LAYOUTS"
#define	SA_REGISTRY	"REGISTRY"

/*
 * Each unique layout will have their own table
 * sa_lot (layout_table)
 */
typedef struct sa_lot {
	avl_node_t lot_num_node;
	avl_node_t lot_hash_node;
	uint64_t lot_num;
	uint64_t lot_hash;
	sa_attr_type_t *lot_attrs;	/* array of attr #'s */
	uint32_t lot_var_sizes;	/* how many aren't fixed size */
	uint32_t lot_attr_count;	/* total attr count */
	list_t 	lot_idx_tab;	/* should be only a couple of entries */
	int	lot_instance;	/* used with lot_hash to identify entry */
} sa_lot_t;

/* index table of offsets */
typedef struct sa_idx_tab {
	list_node_t	sa_next;
	sa_lot_t	*sa_layout;
	uint16_t	*sa_variable_lengths;
	refcount_t	sa_refcount;
	uint32_t	*sa_idx_tab;	/* array of offsets */
} sa_idx_tab_t;

/*
 * Since the offset/index information into the actual data
 * will usually be identical we can share that information with
 * all handles that have the exact same offsets.
 *
 * You would typically only have a large number of different table of
 * contents if you had a several variable sized attributes.
 *
 * Two AVL trees are used to track the attribute layout numbers.
 * one is keyed by number and will be consulted when a DMU_OT_SA
 * object is first read.  The second tree is keyed by the hash signature
 * of the attributes and will be consulted when an attribute is added
 * to determine if we already have an instance of that layout.  Both
 * of these tree's are interconnected.  The only difference is that
 * when an entry is found in the "hash" tree the list of attributes will
 * need to be compared against the list of attributes you have in hand.
 * The assumption is that typically attributes will just be updated and
 * adding a completely new attribute is a very rare operation.
 */
struct sa_os {
	kmutex_t 	sa_lock;
	boolean_t	sa_need_attr_registration;
	boolean_t	sa_force_spill;
	uint64_t	sa_master_obj;
	uint64_t	sa_reg_attr_obj;
	uint64_t	sa_layout_attr_obj;
	int		sa_num_attrs;
	sa_attr_table_t *sa_attr_table;	 /* private attr table */
	sa_update_cb_t	*sa_update_cb;
	avl_tree_t	sa_layout_num_tree;  /* keyed by layout number */
	avl_tree_t	sa_layout_hash_tree; /* keyed by layout hash value */
	int		sa_user_table_sz;
	sa_attr_type_t	*sa_user_table; /* user name->attr mapping table */
};

/*
 * header for all bonus and spill buffers.
 * The header has a fixed portion with a variable number
 * of "lengths" depending on the number of variable sized
 * attribues which are determined by the "layout number"
 */

#define	SA_MAGIC	0x2F505A  /* ZFS SA */
typedef struct sa_hdr_phys {
	uint32_t sa_magic;
	uint16_t sa_layout_info;  /* Encoded with hdrsize and layout number */
	uint16_t sa_lengths[1];	/* optional sizes for variable length attrs */
	/* ... Data follows the lengths.  */
} sa_hdr_phys_t;

/*
 * sa_hdr_phys -> sa_layout_info
 *
 * 16      10       0
 * +--------+-------+
 * | hdrsz  |layout |
 * +--------+-------+
 *
 * Bits 0-10 are the layout number
 * Bits 11-16 are the size of the header.
 * The hdrsize is the number * 8
 *
 * For example.
 * hdrsz of 1 ==> 8 byte header
 *          2 ==> 16 byte header
 *
 */

#define	SA_HDR_LAYOUT_NUM(hdr) BF32_GET(hdr->sa_layout_info, 0, 10)
#define	SA_HDR_SIZE(hdr) BF32_GET_SB(hdr->sa_layout_info, 10, 16, 3, 0)
#define	SA_HDR_LAYOUT_INFO_ENCODE(x, num, size) \
{ \
	BF32_SET_SB(x, 10, 6, 3, 0, size); \
	BF32_SET(x, 0, 10, num); \
}

typedef enum sa_buf_type {
	SA_BONUS = 1,
	SA_SPILL = 2
} sa_buf_type_t;

typedef enum sa_data_op {
	SA_LOOKUP,
	SA_UPDATE,
	SA_ADD,
	SA_REPLACE,
	SA_REMOVE
} sa_data_op_t;

/*
 * Opaque handle used for most sa functions
 *
 * This needs to be kept as small as possible.
 */

struct sa_handle {
	kmutex_t	sa_lock;
	dmu_buf_t	*sa_bonus;
	dmu_buf_t	*sa_spill;
	objset_t	*sa_os;
	void 		*sa_userp;
	sa_idx_tab_t	*sa_bonus_tab;	 /* idx of bonus */
	sa_idx_tab_t	*sa_spill_tab; /* only present if spill activated */
};

#define	SA_GET_DB(hdl, type)	\
	(dmu_buf_impl_t *)((type == SA_BONUS) ? hdl->sa_bonus : hdl->sa_spill)

#define	SA_GET_HDR(hdl, type) \
	((sa_hdr_phys_t *)((dmu_buf_impl_t *)(SA_GET_DB(hdl, \
	type))->db.db_data))

#define	SA_IDX_TAB_GET(hdl, type) \
	(type == SA_BONUS ? hdl->sa_bonus_tab : hdl->sa_spill_tab)

#define	IS_SA_BONUSTYPE(a)	\
	((a == DMU_OT_SA) ? B_TRUE : B_FALSE)

#define	SA_BONUSTYPE_FROM_DB(db) \
	(dmu_get_bonustype((dmu_buf_t *)db))

#define	SA_BLKPTR_SPACE	(DN_MAX_BONUSLEN - sizeof (blkptr_t))

#define	SA_LAYOUT_NUM(x, type) \
	((!IS_SA_BONUSTYPE(type) ? 0 : (((IS_SA_BONUSTYPE(type)) && \
	((SA_HDR_LAYOUT_NUM(x)) == 0)) ? 1 : SA_HDR_LAYOUT_NUM(x))))


#define	SA_REGISTERED_LEN(sa, attr) sa->sa_attr_table[attr].sa_length

#define	SA_ATTR_LEN(sa, idx, attr, hdr) ((SA_REGISTERED_LEN(sa, attr) == 0) ?\
	hdr->sa_lengths[TOC_LEN_IDX(idx->sa_idx_tab[attr])] : \
	SA_REGISTERED_LEN(sa, attr))

#define	SA_SET_HDR(hdr, num, size) \
	{ \
		hdr->sa_magic = SA_MAGIC; \
		SA_HDR_LAYOUT_INFO_ENCODE(hdr->sa_layout_info, num, size); \
	}

#define	SA_ATTR_INFO(sa, idx, hdr, attr, bulk, type, hdl) \
	{ \
		bulk.sa_size = SA_ATTR_LEN(sa, idx, attr, hdr); \
		bulk.sa_buftype = type; \
		bulk.sa_addr = \
		    (void *)((uintptr_t)TOC_OFF(idx->sa_idx_tab[attr]) + \
		    (uintptr_t)hdr); \
}

#define	SA_HDR_SIZE_MATCH_LAYOUT(hdr, tb) \
	(SA_HDR_SIZE(hdr) == (sizeof (sa_hdr_phys_t) + \
	(tb->lot_var_sizes > 1 ? P2ROUNDUP((tb->lot_var_sizes - 1) * \
	sizeof (uint16_t), 8) : 0)))

int sa_add_impl(sa_handle_t *, sa_attr_type_t,
    uint32_t, sa_data_locator_t, void *, dmu_tx_t *);

void sa_register_update_callback_locked(objset_t *, sa_update_cb_t *);
int sa_size_locked(sa_handle_t *, sa_attr_type_t, int *);

void sa_default_locator(void **, uint32_t *, uint32_t, boolean_t, void *);
int sa_attr_size(sa_os_t *, sa_idx_tab_t *, sa_attr_type_t,
    uint16_t *, sa_hdr_phys_t *);

#ifdef	__cplusplus
extern "C" {
#endif

#ifdef	__cplusplus
}
#endif

#endif	/* _SYS_SA_IMPL_H */