/*

 * 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 2009 Sun Microsystems, Inc.  All rights reserved.

 * Use is subject to license terms.

 */

/*

 * Copyright (c) 2012 by Delphix. All rights reserved.

 */

#include <sys/zfs_context.h>

#include <sys/spa.h>

#include <sys/dmu.h>

#include <sys/zio.h>

#include <sys/space_map.h>

static kmem_cache_t *space_seg_cache;

void

space_map_init(void)

{

	ASSERT(space_seg_cache == NULL);

	space_seg_cache = kmem_cache_create("space_seg_cache",

	    sizeof (space_seg_t), 0, NULL, NULL, NULL, NULL, NULL, 0);

}

void

space_map_fini(void)

{

	kmem_cache_destroy(space_seg_cache);

	space_seg_cache = NULL;

}

/*

 * 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, uint8_t shift,

	kmutex_t *lp)

{

	bzero(sm, sizeof (*sm));

	cv_init(&sm->sm_load_cv, NULL, CV_DEFAULT, NULL);

	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_size = size;

	sm->sm_shift = shift;

	sm->sm_lock = lp;

}

void

space_map_destroy(space_map_t *sm)

{

	ASSERT(!sm->sm_loaded && !sm->sm_loading);

	VERIFY0(sm->sm_space);

	avl_destroy(&sm->sm_root);

	cv_destroy(&sm->sm_load_cv);

}

void

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

{

	avl_index_t where;

	space_seg_t *ss_before, *ss_after, *ss;

	uint64_t end = start + size;

	int merge_before, merge_after;

	ASSERT(MUTEX_HELD(sm->sm_lock));

	VERIFY(!sm->sm_condensing);

	VERIFY(size != 0);

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

	VERIFY3U(end, <=, sm->sm_start + sm->sm_size);

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

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

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

	ss = space_map_find(sm, start, size, &where);

	if (ss != NULL) {

		zfs_panic_recover("zfs: allocating allocated segment"

		    "(offset=%llu size=%llu)\n",

		    (longlong_t)start, (longlong_t)size);

		return;

	}

	/* 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);

		if (sm->sm_pp_root) {

			avl_remove(sm->sm_pp_root, ss_before);

			avl_remove(sm->sm_pp_root, ss_after);

		}

		ss_after->ss_start = ss_before->ss_start;

		kmem_cache_free(space_seg_cache, ss_before);

		ss = ss_after;

	} else if (merge_before) {

		ss_before->ss_end = end;

		if (sm->sm_pp_root)

			avl_remove(sm->sm_pp_root, ss_before);

		ss = ss_before;

	} else if (merge_after) {

		ss_after->ss_start = start;

		if (sm->sm_pp_root)

			avl_remove(sm->sm_pp_root, ss_after);

		ss = ss_after;

	} else {

		ss = kmem_cache_alloc(space_seg_cache, KM_SLEEP);

		ss->ss_start = start;

		ss->ss_end = end;

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

	}

	if (sm->sm_pp_root)

		avl_add(sm->sm_pp_root, ss);

	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 *ss, *newseg;

	uint64_t end = start + size;

	int left_over, right_over;

	VERIFY(!sm->sm_condensing);

	ss = space_map_find(sm, start, size, &where);

	/* Make sure we completely overlap with someone */

	if (ss == NULL) {

		zfs_panic_recover("zfs: freeing free segment "

		    "(offset=%llu size=%llu)",

		    (longlong_t)start, (longlong_t)size);

		return;

	}

	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 (sm->sm_pp_root)

		avl_remove(sm->sm_pp_root, ss);

	if (left_over && right_over) {

		newseg = kmem_cache_alloc(space_seg_cache, 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);

		if (sm->sm_pp_root)

			avl_add(sm->sm_pp_root, newseg);

	} else if (left_over) {

		ss->ss_end = start;

	} else if (right_over) {

		ss->ss_start = end;

	} else {

		avl_remove(&sm->sm_root, ss);

		kmem_cache_free(space_seg_cache, ss);

		ss = NULL;

	}

	if (sm->sm_pp_root && ss != NULL)

		avl_add(sm->sm_pp_root, ss);

	sm->sm_space -= size;

}

space_seg_t *

space_map_find(space_map_t *sm, uint64_t start, uint64_t size,

    avl_index_t *wherep)

{

	space_seg_t ssearch, *ss;

	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 = start + size;

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

	if (ss != NULL && ss->ss_start <= start && ss->ss_end >= start + size)

		return (ss);

	return (NULL);

}

boolean_t

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

{

	avl_index_t where;

	return (space_map_find(sm, start, size, &where) != 0);

}

void

space_map_swap(space_map_t **msrc, space_map_t **mdst)

{

	space_map_t *sm;

	ASSERT(MUTEX_HELD((*msrc)->sm_lock));

	ASSERT0((*mdst)->sm_space);

	ASSERT0(avl_numnodes(&(*mdst)->sm_root));

	sm = *msrc;

	*msrc = *mdst;

	*mdst = sm;

}

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_cache_free(space_seg_cache, ss);

	}

	sm->sm_space = 0;

}

void

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

{

	space_seg_t *ss;

	ASSERT(MUTEX_HELD(sm->sm_lock));

	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);

}

/*

 * Wait for any in-progress space_map_load() to complete.

 */

void

space_map_load_wait(space_map_t *sm)

{

	ASSERT(MUTEX_HELD(sm->sm_lock));

	while (sm->sm_loading) {

		ASSERT(!sm->sm_loaded);

		cv_wait(&sm->sm_load_cv, sm->sm_lock);

	}

}

/*

 * Note: space_map_load() will drop sm_lock across dmu_read() calls.

 * The caller must be OK with this.

 */

int

space_map_load(space_map_t *sm, space_map_ops_t *ops, uint8_t maptype,

	space_map_obj_t *smo, objset_t *os)

{

	uint64_t *entry, *entry_map, *entry_map_end;

	uint64_t bufsize, size, offset, end, space;

	uint64_t mapstart = sm->sm_start;

	int error = 0;

	ASSERT(MUTEX_HELD(sm->sm_lock));

	ASSERT(!sm->sm_loaded);

	ASSERT(!sm->sm_loading);

	sm->sm_loading = B_TRUE;

	end = smo->smo_objsize;

	space = smo->smo_alloc;

	ASSERT(sm->sm_ops == NULL);

	VERIFY0(sm->sm_space);

	if (maptype == SM_FREE) {

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

		space = sm->sm_size - space;

	}

	bufsize = 1ULL << SPACE_MAP_BLOCKSHIFT;

	entry_map = zio_buf_alloc(bufsize);

	mutex_exit(sm->sm_lock);

	if (end > bufsize)

		dmu_prefetch(os, smo->smo_object, bufsize, end - bufsize);

	mutex_enter(sm->sm_lock);

	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);

		mutex_exit(sm->sm_lock);

		error = dmu_read(os, smo->smo_object, offset, size, entry_map,

		    DMU_READ_PREFETCH);

		mutex_enter(sm->sm_lock);

		if (error != 0)

			break;

		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);

		}

	}

	if (error == 0) {

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

		sm->sm_loaded = B_TRUE;

		sm->sm_ops = ops;

		if (ops != NULL)

			ops->smop_load(sm);

	} else {

		space_map_vacate(sm, NULL, NULL);

	}

	zio_buf_free(entry_map, bufsize);

	sm->sm_loading = B_FALSE;

	cv_broadcast(&sm->sm_load_cv);

	return (error);

}

void

space_map_unload(space_map_t *sm)

{

	ASSERT(MUTEX_HELD(sm->sm_lock));

	if (sm->sm_loaded && sm->sm_ops != NULL)

		sm->sm_ops->smop_unload(sm);

	sm->sm_loaded = B_FALSE;

	sm->sm_ops = NULL;

	space_map_vacate(sm, NULL, NULL);

}

uint64_t

space_map_maxsize(space_map_t *sm)

{

	ASSERT(sm->sm_ops != NULL);

	return (sm->sm_ops->smop_max(sm));

}

uint64_t

space_map_alloc(space_map_t *sm, uint64_t size)

{

	uint64_t start;

	start = sm->sm_ops->smop_alloc(sm, size);

	if (start != -1ULL)

		space_map_remove(sm, start, size);

	return (start);

}

void

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

{

	sm->sm_ops->smop_claim(sm, start, size);

	space_map_remove(sm, start, size);

}

void

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

{

	space_map_add(sm, start, size);

	sm->sm_ops->smop_free(sm, start, size);

}

/*

 * Note: space_map_sync() will drop sm_lock across dmu_write() calls.

 */

void

space_map_sync(space_map_t *sm, uint8_t maptype,

	space_map_obj_t *smo, objset_t *os, dmu_tx_t *tx)

{

	spa_t *spa = dmu_objset_spa(os);

	avl_tree_t *t = &sm->sm_root;

	space_seg_t *ss;

	uint64_t bufsize, start, size, run_len, total, sm_space, nodes;

	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);

	if (maptype == SM_ALLOC)

		smo->smo_alloc += sm->sm_space;

	else

		smo->smo_alloc -= sm->sm_space;

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

	bufsize = MIN(bufsize, 1ULL << SPACE_MAP_BLOCKSHIFT);

	entry_map = zio_buf_alloc(bufsize);

	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));

	total = 0;

	nodes = avl_numnodes(&sm->sm_root);

	sm_space = sm->sm_space;

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

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

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

		total += size;

		size >>= sm->sm_shift;

		while (size) {

			run_len = MIN(size, SM_RUN_MAX);

			if (entry == entry_map_end) {

				mutex_exit(sm->sm_lock);

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

				    bufsize, entry_map, tx);

				mutex_enter(sm->sm_lock);

				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;

		}

	}