/*

 * 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	"%Z%%M%	%I%	%E% SMI"

#include <sys/zfs_context.h>

#include <sys/spa.h>

#include <sys/dmu.h>

#include <sys/space_map.h>

/*

 * Space map routines.

 * NOTE: caller is responsible for all locking.

 */

static int

space_map_seg_compare(const void *x1, const void *x2)

{

	const space_seg_t *s1 = x1;

	const space_seg_t *s2 = x2;

	if (s1->ss_start < s2->ss_start) {

		if (s1->ss_end > s2->ss_start)

			return (0);

		return (-1);

	}

	if (s1->ss_start > s2->ss_start) {

		if (s1->ss_start < s2->ss_end)

			return (0);

		return (1);

	}

	return (0);

}

void

space_map_create(space_map_t *sm, uint64_t start, uint64_t size, uint64_t shift,

	kmutex_t *lp)

{

	avl_create(&sm->sm_root, space_map_seg_compare,

	    sizeof (space_seg_t), offsetof(struct space_seg, ss_node));

	sm->sm_start = start;

	sm->sm_end = start + size;

	sm->sm_size = size;

	sm->sm_shift = shift;

	sm->sm_space = 0;

	sm->sm_lock = lp;

}

void

space_map_destroy(space_map_t *sm)

{

	VERIFY3U(sm->sm_space, ==, 0);

	avl_destroy(&sm->sm_root);

}

void

space_map_add(space_map_t *sm, uint64_t start, uint64_t size)

{

	avl_index_t where;

	space_seg_t ssearch, *ss_before, *ss_after, *ss;

	uint64_t end = start + size;

	int merge_before, merge_after;

	ASSERT(MUTEX_HELD(sm->sm_lock));

	VERIFY(size != 0);

	VERIFY3U(start, >=, sm->sm_start);

	VERIFY3U(end, <=, sm->sm_end);

	VERIFY(sm->sm_space + size <= sm->sm_size);

	VERIFY(P2PHASE(start, 1ULL << sm->sm_shift) == 0);

	VERIFY(P2PHASE(size, 1ULL << sm->sm_shift) == 0);

	ssearch.ss_start = start;

	ssearch.ss_end = end;

	ss = avl_find(&sm->sm_root, &ssearch, &where);

	/* Make sure we don't overlap with either of our neighbors */

	VERIFY(ss == NULL);

	ss_before = avl_nearest(&sm->sm_root, where, AVL_BEFORE);

	ss_after = avl_nearest(&sm->sm_root, where, AVL_AFTER);

	merge_before = (ss_before != NULL && ss_before->ss_end == start);

	merge_after = (ss_after != NULL && ss_after->ss_start == end);

	if (merge_before && merge_after) {

		avl_remove(&sm->sm_root, ss_before);

		ss_after->ss_start = ss_before->ss_start;

		kmem_free(ss_before, sizeof (*ss_before));

	} else if (merge_before) {

		ss_before->ss_end = end;

	} else if (merge_after) {

		ss_after->ss_start = start;

	} else {

		ss = kmem_alloc(sizeof (*ss), KM_SLEEP);

		ss->ss_start = start;

		ss->ss_end = end;

		avl_insert(&sm->sm_root, ss, where);

	}

	sm->sm_space += size;

}

void

space_map_remove(space_map_t *sm, uint64_t start, uint64_t size)

{

	avl_index_t where;

	space_seg_t ssearch, *ss, *newseg;

	uint64_t end = start + size;

	int left_over, right_over;

	ASSERT(MUTEX_HELD(sm->sm_lock));

	VERIFY(size != 0);

	VERIFY(P2PHASE(start, 1ULL << sm->sm_shift) == 0);

	VERIFY(P2PHASE(size, 1ULL << sm->sm_shift) == 0);

	ssearch.ss_start = start;

	ssearch.ss_end = end;

	ss = avl_find(&sm->sm_root, &ssearch, &where);

	/* Make sure we completely overlap with someone */

	VERIFY(ss != NULL);

	VERIFY3U(ss->ss_start, <=, start);

	VERIFY3U(ss->ss_end, >=, end);

	VERIFY(sm->sm_space - size <= sm->sm_size);

	left_over = (ss->ss_start != start);

	right_over = (ss->ss_end != end);

	if (left_over && right_over) {

		newseg = kmem_alloc(sizeof (*newseg), KM_SLEEP);

		newseg->ss_start = end;

		newseg->ss_end = ss->ss_end;

		ss->ss_end = start;

		avl_insert_here(&sm->sm_root, newseg, ss, AVL_AFTER);

	} else if (left_over) {

		ss->ss_end = start;

	} else if (right_over) {

		ss->ss_start = end;

	} else {

		avl_remove(&sm->sm_root, ss);

		kmem_free(ss, sizeof (*ss));

	}

	sm->sm_space -= size;

}

int

space_map_contains(space_map_t *sm, uint64_t start, uint64_t size)

{

	avl_index_t where;

	space_seg_t ssearch, *ss;

	uint64_t end = start + size;

	ASSERT(MUTEX_HELD(sm->sm_lock));

	VERIFY(size != 0);

	VERIFY(P2PHASE(start, 1ULL << sm->sm_shift) == 0);

	VERIFY(P2PHASE(size, 1ULL << sm->sm_shift) == 0);

	ssearch.ss_start = start;

	ssearch.ss_end = end;

	ss = avl_find(&sm->sm_root, &ssearch, &where);

	return (ss != NULL && ss->ss_start <= start && ss->ss_end >= end);

}

void

space_map_vacate(space_map_t *sm, space_map_func_t *func, space_map_t *mdest)

{

	space_seg_t *ss;

	void *cookie = NULL;

	ASSERT(MUTEX_HELD(sm->sm_lock));

	while ((ss = avl_destroy_nodes(&sm->sm_root, &cookie)) != NULL) {

		if (func != NULL)

			func(mdest, ss->ss_start, ss->ss_end - ss->ss_start);

		kmem_free(ss, sizeof (*ss));

	}

	sm->sm_space = 0;

}

void

space_map_iterate(space_map_t *sm, space_map_func_t *func, space_map_t *mdest)

{

	space_seg_t *ss;

	for (ss = avl_first(&sm->sm_root); ss; ss = AVL_NEXT(&sm->sm_root, ss))

		func(mdest, ss->ss_start, ss->ss_end - ss->ss_start);

}

void

space_map_merge(space_map_t *src, space_map_t *dest)

{

	space_map_vacate(src, space_map_add, dest);

}

void

space_map_excise(space_map_t *sm, uint64_t start, uint64_t size)

{

	avl_tree_t *t = &sm->sm_root;

	avl_index_t where;

	space_seg_t *ss, search;

	uint64_t end = start + size;

	uint64_t rm_start, rm_end;

	ASSERT(MUTEX_HELD(sm->sm_lock));

	search.ss_start = start;

	search.ss_end = start;

	for (;;) {

		ss = avl_find(t, &search, &where);

		if (ss == NULL)

			ss = avl_nearest(t, where, AVL_AFTER);

		if (ss == NULL || ss->ss_start >= end)

			break;

		rm_start = MAX(ss->ss_start, start);

		rm_end = MIN(ss->ss_end, end);

		space_map_remove(sm, rm_start, rm_end - rm_start);

	}

}

/*

 * Replace smd with the union of smd and sms.

 */

void

space_map_union(space_map_t *smd, space_map_t *sms)

{

	avl_tree_t *t = &sms->sm_root;

	space_seg_t *ss;

	ASSERT(MUTEX_HELD(smd->sm_lock));

	/*

	 * For each source segment, remove any intersections with the

	 * destination, then add the source segment to the destination.

	 */

	for (ss = avl_first(t); ss != NULL; ss = AVL_NEXT(t, ss)) {

		space_map_excise(smd, ss->ss_start, ss->ss_end - ss->ss_start);

		space_map_add(smd, ss->ss_start, ss->ss_end - ss->ss_start);

	}

}

int

space_map_load(space_map_t *sm, space_map_obj_t *smo, uint8_t maptype,

	objset_t *os, uint64_t end, uint64_t space)

{

	uint64_t *entry, *entry_map, *entry_map_end;

	uint64_t bufsize, size, offset;

	uint64_t mapstart = sm->sm_start;

	ASSERT(MUTEX_HELD(sm->sm_lock));

	VERIFY3U(sm->sm_space, ==, 0);

	bufsize = MIN(end, SPACE_MAP_CHUNKSIZE);

	entry_map = kmem_alloc(bufsize, KM_SLEEP);

	if (maptype == SM_FREE) {

		space_map_add(sm, sm->sm_start, sm->sm_size);

		space = sm->sm_size - space;

	}

	for (offset = 0; offset < end; offset += bufsize) {

		size = MIN(end - offset, bufsize);

		VERIFY(P2PHASE(size, sizeof (uint64_t)) == 0);

		VERIFY(size != 0);

		dprintf("object=%llu  offset=%llx  size=%llx\n",

		    smo->smo_object, offset, size);

		VERIFY(0 == dmu_read(os, smo->smo_object, offset, size,

		    entry_map));

		entry_map_end = entry_map + (size / sizeof (uint64_t));

		for (entry = entry_map; entry < entry_map_end; entry++) {

			uint64_t e = *entry;

			if (SM_DEBUG_DECODE(e))		/* Skip debug entries */

				continue;

			(SM_TYPE_DECODE(e) == maptype ?

			    space_map_add : space_map_remove)(sm,

			    (SM_OFFSET_DECODE(e) << sm->sm_shift) + mapstart,

			    SM_RUN_DECODE(e) << sm->sm_shift);

		}

	}

	VERIFY3U(sm->sm_space, ==, space);

	kmem_free(entry_map, bufsize);

	return (0);

}

void

space_map_sync(space_map_t *sm, space_map_t *dest, space_map_obj_t *smo,

    uint8_t maptype, objset_t *os, dmu_tx_t *tx)

{

	spa_t *spa = dmu_objset_spa(os);

	void *cookie = NULL;

	space_seg_t *ss;

	uint64_t bufsize, start, size, run_len;

	uint64_t *entry, *entry_map, *entry_map_end;

	ASSERT(MUTEX_HELD(sm->sm_lock));

	if (sm->sm_space == 0)

		return;

	dprintf("object %4llu, txg %llu, pass %d, %c, count %lu, space %llx\n",

	    smo->smo_object, dmu_tx_get_txg(tx), spa_sync_pass(spa),

	    maptype == SM_ALLOC ? 'A' : 'F', avl_numnodes(&sm->sm_root),

	    sm->sm_space);

	bufsize = (8 + avl_numnodes(&sm->sm_root)) * sizeof (uint64_t);

	bufsize = MIN(bufsize, SPACE_MAP_CHUNKSIZE);

	entry_map = kmem_alloc(bufsize, KM_SLEEP);

	entry_map_end = entry_map + (bufsize / sizeof (uint64_t));

	entry = entry_map;

	*entry++ = SM_DEBUG_ENCODE(1) |

	    SM_DEBUG_ACTION_ENCODE(maptype) |

	    SM_DEBUG_SYNCPASS_ENCODE(spa_sync_pass(spa)) |

	    SM_DEBUG_TXG_ENCODE(dmu_tx_get_txg(tx));

	while ((ss = avl_destroy_nodes(&sm->sm_root, &cookie)) != NULL) {

		size = ss->ss_end - ss->ss_start;

		start = (ss->ss_start - sm->sm_start) >> sm->sm_shift;

		if (dest)

			space_map_add(dest, ss->ss_start, size);

		sm->sm_space -= size;

		size >>= sm->sm_shift;

		while (size) {

			run_len = MIN(size, SM_RUN_MAX);

			if (entry == entry_map_end) {

				dmu_write(os, smo->smo_object, smo->smo_objsize,

				    bufsize, entry_map, tx);

				smo->smo_objsize += bufsize;

				entry = entry_map;

			}

			*entry++ = SM_OFFSET_ENCODE(start) |

			    SM_TYPE_ENCODE(maptype) |

			    SM_RUN_ENCODE(run_len);

			start += run_len;

			size -= run_len;

		}

		kmem_free(ss, sizeof (*ss));

	}

	if (entry != entry_map) {

		size = (entry - entry_map) * sizeof (uint64_t);

		dmu_write(os, smo->smo_object, smo->smo_objsize,

		    size, entry_map, tx);

		smo->smo_objsize += size;

	}

	kmem_free(entry_map, bufsize);

	VERIFY3U(sm->sm_space, ==, 0);

}

void

space_map_write(space_map_t *sm, space_map_obj_t *smo, objset_t *os,

    dmu_tx_t *tx)

{

	uint64_t oldsize = smo->smo_objsize;

	VERIFY(0 == dmu_free_range(os, smo->smo_object, 0,

	    smo->smo_objsize, tx));

	smo->smo_objsize = 0;

	VERIFY3U(sm->sm_space, ==, smo->smo_alloc);

	space_map_sync(sm, NULL, smo, SM_ALLOC, os, tx);

	dprintf("write sm object %llu from %llu to %llu bytes in txg %llu\n",

	    smo->smo_object, oldsize, smo->smo_objsize, dmu_tx_get_txg(tx));

}