1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * Copyright (C) 2008 Red Hat.  All rights reserved.
 
 
 
 
 
 
 
 
 
 
 
 
 
 
   4 */
   5
   6#include <linux/pagemap.h>
   7#include <linux/sched.h>
   8#include <linux/sched/signal.h>
   9#include <linux/slab.h>
  10#include <linux/math64.h>
  11#include <linux/ratelimit.h>
  12#include <linux/error-injection.h>
  13#include <linux/sched/mm.h>
  14#include "ctree.h"
  15#include "free-space-cache.h"
  16#include "transaction.h"
  17#include "disk-io.h"
  18#include "extent_io.h"
  19#include "inode-map.h"
  20#include "volumes.h"
  21#include "space-info.h"
  22#include "delalloc-space.h"
  23#include "block-group.h"
  24
  25#define BITS_PER_BITMAP		(PAGE_SIZE * 8UL)
  26#define MAX_CACHE_BYTES_PER_GIG	SZ_32K
  27
  28struct btrfs_trim_range {
  29	u64 start;
  30	u64 bytes;
  31	struct list_head list;
  32};
  33
  34static int link_free_space(struct btrfs_free_space_ctl *ctl,
  35			   struct btrfs_free_space *info);
  36static void unlink_free_space(struct btrfs_free_space_ctl *ctl,
  37			      struct btrfs_free_space *info);
  38static int btrfs_wait_cache_io_root(struct btrfs_root *root,
  39			     struct btrfs_trans_handle *trans,
  40			     struct btrfs_io_ctl *io_ctl,
  41			     struct btrfs_path *path);
  42
  43static struct inode *__lookup_free_space_inode(struct btrfs_root *root,
  44					       struct btrfs_path *path,
  45					       u64 offset)
  46{
  47	struct btrfs_fs_info *fs_info = root->fs_info;
  48	struct btrfs_key key;
  49	struct btrfs_key location;
  50	struct btrfs_disk_key disk_key;
  51	struct btrfs_free_space_header *header;
  52	struct extent_buffer *leaf;
  53	struct inode *inode = NULL;
  54	unsigned nofs_flag;
  55	int ret;
  56
  57	key.objectid = BTRFS_FREE_SPACE_OBJECTID;
  58	key.offset = offset;
  59	key.type = 0;
  60
  61	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
  62	if (ret < 0)
  63		return ERR_PTR(ret);
  64	if (ret > 0) {
  65		btrfs_release_path(path);
  66		return ERR_PTR(-ENOENT);
  67	}
  68
  69	leaf = path->nodes[0];
  70	header = btrfs_item_ptr(leaf, path->slots[0],
  71				struct btrfs_free_space_header);
  72	btrfs_free_space_key(leaf, header, &disk_key);
  73	btrfs_disk_key_to_cpu(&location, &disk_key);
  74	btrfs_release_path(path);
  75
  76	/*
  77	 * We are often under a trans handle at this point, so we need to make
  78	 * sure NOFS is set to keep us from deadlocking.
  79	 */
  80	nofs_flag = memalloc_nofs_save();
  81	inode = btrfs_iget_path(fs_info->sb, &location, root, NULL, path);
  82	btrfs_release_path(path);
  83	memalloc_nofs_restore(nofs_flag);
  84	if (IS_ERR(inode))
  85		return inode;
 
 
 
 
  86
  87	mapping_set_gfp_mask(inode->i_mapping,
  88			mapping_gfp_constraint(inode->i_mapping,
  89			~(__GFP_FS | __GFP_HIGHMEM)));
  90
  91	return inode;
  92}
  93
  94struct inode *lookup_free_space_inode(
  95		struct btrfs_block_group_cache *block_group,
  96		struct btrfs_path *path)
  97{
  98	struct btrfs_fs_info *fs_info = block_group->fs_info;
  99	struct inode *inode = NULL;
 
 100	u32 flags = BTRFS_INODE_NODATASUM | BTRFS_INODE_NODATACOW;
 101
 102	spin_lock(&block_group->lock);
 103	if (block_group->inode)
 104		inode = igrab(block_group->inode);
 105	spin_unlock(&block_group->lock);
 106	if (inode)
 107		return inode;
 108
 109	inode = __lookup_free_space_inode(fs_info->tree_root, path,
 110					  block_group->key.objectid);
 111	if (IS_ERR(inode))
 112		return inode;
 113
 114	spin_lock(&block_group->lock);
 115	if (!((BTRFS_I(inode)->flags & flags) == flags)) {
 116		btrfs_info(fs_info, "Old style space inode found, converting.");
 117		BTRFS_I(inode)->flags |= BTRFS_INODE_NODATASUM |
 118			BTRFS_INODE_NODATACOW;
 119		block_group->disk_cache_state = BTRFS_DC_CLEAR;
 120	}
 121
 122	if (!block_group->iref) {
 123		block_group->inode = igrab(inode);
 124		block_group->iref = 1;
 125	}
 126	spin_unlock(&block_group->lock);
 127
 128	return inode;
 129}
 130
 131static int __create_free_space_inode(struct btrfs_root *root,
 132				     struct btrfs_trans_handle *trans,
 133				     struct btrfs_path *path,
 134				     u64 ino, u64 offset)
 135{
 136	struct btrfs_key key;
 137	struct btrfs_disk_key disk_key;
 138	struct btrfs_free_space_header *header;
 139	struct btrfs_inode_item *inode_item;
 140	struct extent_buffer *leaf;
 141	u64 flags = BTRFS_INODE_NOCOMPRESS | BTRFS_INODE_PREALLOC;
 142	int ret;
 143
 144	ret = btrfs_insert_empty_inode(trans, root, path, ino);
 145	if (ret)
 146		return ret;
 147
 148	/* We inline crc's for the free disk space cache */
 149	if (ino != BTRFS_FREE_INO_OBJECTID)
 150		flags |= BTRFS_INODE_NODATASUM | BTRFS_INODE_NODATACOW;
 151
 152	leaf = path->nodes[0];
 153	inode_item = btrfs_item_ptr(leaf, path->slots[0],
 154				    struct btrfs_inode_item);
 155	btrfs_item_key(leaf, &disk_key, path->slots[0]);
 156	memzero_extent_buffer(leaf, (unsigned long)inode_item,
 157			     sizeof(*inode_item));
 158	btrfs_set_inode_generation(leaf, inode_item, trans->transid);
 159	btrfs_set_inode_size(leaf, inode_item, 0);
 160	btrfs_set_inode_nbytes(leaf, inode_item, 0);
 161	btrfs_set_inode_uid(leaf, inode_item, 0);
 162	btrfs_set_inode_gid(leaf, inode_item, 0);
 163	btrfs_set_inode_mode(leaf, inode_item, S_IFREG | 0600);
 164	btrfs_set_inode_flags(leaf, inode_item, flags);
 165	btrfs_set_inode_nlink(leaf, inode_item, 1);
 166	btrfs_set_inode_transid(leaf, inode_item, trans->transid);
 167	btrfs_set_inode_block_group(leaf, inode_item, offset);
 168	btrfs_mark_buffer_dirty(leaf);
 169	btrfs_release_path(path);
 170
 171	key.objectid = BTRFS_FREE_SPACE_OBJECTID;
 172	key.offset = offset;
 173	key.type = 0;
 174	ret = btrfs_insert_empty_item(trans, root, path, &key,
 175				      sizeof(struct btrfs_free_space_header));
 176	if (ret < 0) {
 177		btrfs_release_path(path);
 178		return ret;
 179	}
 180
 181	leaf = path->nodes[0];
 182	header = btrfs_item_ptr(leaf, path->slots[0],
 183				struct btrfs_free_space_header);
 184	memzero_extent_buffer(leaf, (unsigned long)header, sizeof(*header));
 185	btrfs_set_free_space_key(leaf, header, &disk_key);
 186	btrfs_mark_buffer_dirty(leaf);
 187	btrfs_release_path(path);
 188
 189	return 0;
 190}
 191
 192int create_free_space_inode(struct btrfs_trans_handle *trans,
 
 193			    struct btrfs_block_group_cache *block_group,
 194			    struct btrfs_path *path)
 195{
 196	int ret;
 197	u64 ino;
 198
 199	ret = btrfs_find_free_objectid(trans->fs_info->tree_root, &ino);
 200	if (ret < 0)
 201		return ret;
 202
 203	return __create_free_space_inode(trans->fs_info->tree_root, trans, path,
 204					 ino, block_group->key.objectid);
 205}
 206
 207int btrfs_check_trunc_cache_free_space(struct btrfs_fs_info *fs_info,
 208				       struct btrfs_block_rsv *rsv)
 209{
 210	u64 needed_bytes;
 211	int ret;
 212
 213	/* 1 for slack space, 1 for updating the inode */
 214	needed_bytes = btrfs_calc_insert_metadata_size(fs_info, 1) +
 215		btrfs_calc_metadata_size(fs_info, 1);
 216
 217	spin_lock(&rsv->lock);
 218	if (rsv->reserved < needed_bytes)
 219		ret = -ENOSPC;
 220	else
 221		ret = 0;
 222	spin_unlock(&rsv->lock);
 223	return ret;
 224}
 225
 226int btrfs_truncate_free_space_cache(struct btrfs_trans_handle *trans,
 
 227				    struct btrfs_block_group_cache *block_group,
 228				    struct inode *inode)
 229{
 230	struct btrfs_root *root = BTRFS_I(inode)->root;
 231	int ret = 0;
 
 232	bool locked = false;
 233
 234	if (block_group) {
 235		struct btrfs_path *path = btrfs_alloc_path();
 
 
 236
 237		if (!path) {
 238			ret = -ENOMEM;
 239			goto fail;
 240		}
 241		locked = true;
 242		mutex_lock(&trans->transaction->cache_write_mutex);
 243		if (!list_empty(&block_group->io_list)) {
 244			list_del_init(&block_group->io_list);
 245
 246			btrfs_wait_cache_io(trans, block_group, path);
 247			btrfs_put_block_group(block_group);
 248		}
 249
 250		/*
 251		 * now that we've truncated the cache away, its no longer
 252		 * setup or written
 253		 */
 254		spin_lock(&block_group->lock);
 255		block_group->disk_cache_state = BTRFS_DC_CLEAR;
 256		spin_unlock(&block_group->lock);
 257		btrfs_free_path(path);
 258	}
 
 259
 260	btrfs_i_size_write(BTRFS_I(inode), 0);
 261	truncate_pagecache(inode, 0);
 262
 263	/*
 264	 * We skip the throttling logic for free space cache inodes, so we don't
 265	 * need to check for -EAGAIN.
 
 
 266	 */
 267	ret = btrfs_truncate_inode_items(trans, root, inode,
 268					 0, BTRFS_EXTENT_DATA_KEY);
 269	if (ret)
 270		goto fail;
 271
 272	ret = btrfs_update_inode(trans, root, inode);
 273
 274fail:
 275	if (locked)
 276		mutex_unlock(&trans->transaction->cache_write_mutex);
 277	if (ret)
 278		btrfs_abort_transaction(trans, ret);
 279
 280	return ret;
 281}
 282
 283static void readahead_cache(struct inode *inode)
 284{
 285	struct file_ra_state *ra;
 286	unsigned long last_index;
 287
 288	ra = kzalloc(sizeof(*ra), GFP_NOFS);
 289	if (!ra)
 290		return;
 291
 292	file_ra_state_init(ra, inode->i_mapping);
 293	last_index = (i_size_read(inode) - 1) >> PAGE_SHIFT;
 294
 295	page_cache_sync_readahead(inode->i_mapping, ra, NULL, 0, last_index);
 296
 297	kfree(ra);
 
 
 298}
 299
 300static int io_ctl_init(struct btrfs_io_ctl *io_ctl, struct inode *inode,
 301		       int write)
 302{
 303	int num_pages;
 304	int check_crcs = 0;
 305
 306	num_pages = DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE);
 307
 308	if (btrfs_ino(BTRFS_I(inode)) != BTRFS_FREE_INO_OBJECTID)
 309		check_crcs = 1;
 310
 311	/* Make sure we can fit our crcs and generation into the first page */
 312	if (write && check_crcs &&
 313	    (num_pages * sizeof(u32) + sizeof(u64)) > PAGE_SIZE)
 314		return -ENOSPC;
 315
 316	memset(io_ctl, 0, sizeof(struct btrfs_io_ctl));
 317
 318	io_ctl->pages = kcalloc(num_pages, sizeof(struct page *), GFP_NOFS);
 319	if (!io_ctl->pages)
 320		return -ENOMEM;
 321
 322	io_ctl->num_pages = num_pages;
 323	io_ctl->fs_info = btrfs_sb(inode->i_sb);
 324	io_ctl->check_crcs = check_crcs;
 325	io_ctl->inode = inode;
 326
 327	return 0;
 328}
 329ALLOW_ERROR_INJECTION(io_ctl_init, ERRNO);
 330
 331static void io_ctl_free(struct btrfs_io_ctl *io_ctl)
 332{
 333	kfree(io_ctl->pages);
 334	io_ctl->pages = NULL;
 335}
 336
 337static void io_ctl_unmap_page(struct btrfs_io_ctl *io_ctl)
 338{
 339	if (io_ctl->cur) {
 340		io_ctl->cur = NULL;
 341		io_ctl->orig = NULL;
 342	}
 343}
 344
 345static void io_ctl_map_page(struct btrfs_io_ctl *io_ctl, int clear)
 346{
 347	ASSERT(io_ctl->index < io_ctl->num_pages);
 348	io_ctl->page = io_ctl->pages[io_ctl->index++];
 349	io_ctl->cur = page_address(io_ctl->page);
 350	io_ctl->orig = io_ctl->cur;
 351	io_ctl->size = PAGE_SIZE;
 352	if (clear)
 353		clear_page(io_ctl->cur);
 354}
 355
 356static void io_ctl_drop_pages(struct btrfs_io_ctl *io_ctl)
 357{
 358	int i;
 359
 360	io_ctl_unmap_page(io_ctl);
 361
 362	for (i = 0; i < io_ctl->num_pages; i++) {
 363		if (io_ctl->pages[i]) {
 364			ClearPageChecked(io_ctl->pages[i]);
 365			unlock_page(io_ctl->pages[i]);
 366			put_page(io_ctl->pages[i]);
 367		}
 368	}
 369}
 370
 371static int io_ctl_prepare_pages(struct btrfs_io_ctl *io_ctl, struct inode *inode,
 372				int uptodate)
 373{
 374	struct page *page;
 375	gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
 376	int i;
 377
 378	for (i = 0; i < io_ctl->num_pages; i++) {
 379		page = find_or_create_page(inode->i_mapping, i, mask);
 380		if (!page) {
 381			io_ctl_drop_pages(io_ctl);
 382			return -ENOMEM;
 383		}
 384		io_ctl->pages[i] = page;
 385		if (uptodate && !PageUptodate(page)) {
 386			btrfs_readpage(NULL, page);
 387			lock_page(page);
 388			if (!PageUptodate(page)) {
 389				btrfs_err(BTRFS_I(inode)->root->fs_info,
 390					   "error reading free space cache");
 391				io_ctl_drop_pages(io_ctl);
 392				return -EIO;
 393			}
 394		}
 395	}
 396
 397	for (i = 0; i < io_ctl->num_pages; i++) {
 398		clear_page_dirty_for_io(io_ctl->pages[i]);
 399		set_page_extent_mapped(io_ctl->pages[i]);
 400	}
 401
 402	return 0;
 403}
 404
 405static void io_ctl_set_generation(struct btrfs_io_ctl *io_ctl, u64 generation)
 406{
 407	__le64 *val;
 408
 409	io_ctl_map_page(io_ctl, 1);
 410
 411	/*
 412	 * Skip the csum areas.  If we don't check crcs then we just have a
 413	 * 64bit chunk at the front of the first page.
 414	 */
 415	if (io_ctl->check_crcs) {
 416		io_ctl->cur += (sizeof(u32) * io_ctl->num_pages);
 417		io_ctl->size -= sizeof(u64) + (sizeof(u32) * io_ctl->num_pages);
 418	} else {
 419		io_ctl->cur += sizeof(u64);
 420		io_ctl->size -= sizeof(u64) * 2;
 421	}
 422
 423	val = io_ctl->cur;
 424	*val = cpu_to_le64(generation);
 425	io_ctl->cur += sizeof(u64);
 426}
 427
 428static int io_ctl_check_generation(struct btrfs_io_ctl *io_ctl, u64 generation)
 429{
 430	__le64 *gen;
 431
 432	/*
 433	 * Skip the crc area.  If we don't check crcs then we just have a 64bit
 434	 * chunk at the front of the first page.
 435	 */
 436	if (io_ctl->check_crcs) {
 437		io_ctl->cur += sizeof(u32) * io_ctl->num_pages;
 438		io_ctl->size -= sizeof(u64) +
 439			(sizeof(u32) * io_ctl->num_pages);
 440	} else {
 441		io_ctl->cur += sizeof(u64);
 442		io_ctl->size -= sizeof(u64) * 2;
 443	}
 444
 445	gen = io_ctl->cur;
 446	if (le64_to_cpu(*gen) != generation) {
 447		btrfs_err_rl(io_ctl->fs_info,
 448			"space cache generation (%llu) does not match inode (%llu)",
 449				*gen, generation);
 450		io_ctl_unmap_page(io_ctl);
 451		return -EIO;
 452	}
 453	io_ctl->cur += sizeof(u64);
 454	return 0;
 455}
 456
 457static void io_ctl_set_crc(struct btrfs_io_ctl *io_ctl, int index)
 458{
 459	u32 *tmp;
 460	u32 crc = ~(u32)0;
 461	unsigned offset = 0;
 462
 463	if (!io_ctl->check_crcs) {
 464		io_ctl_unmap_page(io_ctl);
 465		return;
 466	}
 467
 468	if (index == 0)
 469		offset = sizeof(u32) * io_ctl->num_pages;
 470
 471	crc = btrfs_crc32c(crc, io_ctl->orig + offset, PAGE_SIZE - offset);
 472	btrfs_crc32c_final(crc, (u8 *)&crc);
 
 473	io_ctl_unmap_page(io_ctl);
 474	tmp = page_address(io_ctl->pages[0]);
 475	tmp += index;
 476	*tmp = crc;
 477}
 478
 479static int io_ctl_check_crc(struct btrfs_io_ctl *io_ctl, int index)
 480{
 481	u32 *tmp, val;
 482	u32 crc = ~(u32)0;
 483	unsigned offset = 0;
 484
 485	if (!io_ctl->check_crcs) {
 486		io_ctl_map_page(io_ctl, 0);
 487		return 0;
 488	}
 489
 490	if (index == 0)
 491		offset = sizeof(u32) * io_ctl->num_pages;
 492
 493	tmp = page_address(io_ctl->pages[0]);
 494	tmp += index;
 495	val = *tmp;
 496
 497	io_ctl_map_page(io_ctl, 0);
 498	crc = btrfs_crc32c(crc, io_ctl->orig + offset, PAGE_SIZE - offset);
 499	btrfs_crc32c_final(crc, (u8 *)&crc);
 
 500	if (val != crc) {
 501		btrfs_err_rl(io_ctl->fs_info,
 502			"csum mismatch on free space cache");
 503		io_ctl_unmap_page(io_ctl);
 504		return -EIO;
 505	}
 506
 507	return 0;
 508}
 509
 510static int io_ctl_add_entry(struct btrfs_io_ctl *io_ctl, u64 offset, u64 bytes,
 511			    void *bitmap)
 512{
 513	struct btrfs_free_space_entry *entry;
 514
 515	if (!io_ctl->cur)
 516		return -ENOSPC;
 517
 518	entry = io_ctl->cur;
 519	entry->offset = cpu_to_le64(offset);
 520	entry->bytes = cpu_to_le64(bytes);
 521	entry->type = (bitmap) ? BTRFS_FREE_SPACE_BITMAP :
 522		BTRFS_FREE_SPACE_EXTENT;
 523	io_ctl->cur += sizeof(struct btrfs_free_space_entry);
 524	io_ctl->size -= sizeof(struct btrfs_free_space_entry);
 525
 526	if (io_ctl->size >= sizeof(struct btrfs_free_space_entry))
 527		return 0;
 528
 529	io_ctl_set_crc(io_ctl, io_ctl->index - 1);
 530
 531	/* No more pages to map */
 532	if (io_ctl->index >= io_ctl->num_pages)
 533		return 0;
 534
 535	/* map the next page */
 536	io_ctl_map_page(io_ctl, 1);
 537	return 0;
 538}
 539
 540static int io_ctl_add_bitmap(struct btrfs_io_ctl *io_ctl, void *bitmap)
 541{
 542	if (!io_ctl->cur)
 543		return -ENOSPC;
 544
 545	/*
 546	 * If we aren't at the start of the current page, unmap this one and
 547	 * map the next one if there is any left.
 548	 */
 549	if (io_ctl->cur != io_ctl->orig) {
 550		io_ctl_set_crc(io_ctl, io_ctl->index - 1);
 551		if (io_ctl->index >= io_ctl->num_pages)
 552			return -ENOSPC;
 553		io_ctl_map_page(io_ctl, 0);
 554	}
 555
 556	copy_page(io_ctl->cur, bitmap);
 557	io_ctl_set_crc(io_ctl, io_ctl->index - 1);
 558	if (io_ctl->index < io_ctl->num_pages)
 559		io_ctl_map_page(io_ctl, 0);
 560	return 0;
 561}
 562
 563static void io_ctl_zero_remaining_pages(struct btrfs_io_ctl *io_ctl)
 564{
 565	/*
 566	 * If we're not on the boundary we know we've modified the page and we
 567	 * need to crc the page.
 568	 */
 569	if (io_ctl->cur != io_ctl->orig)
 570		io_ctl_set_crc(io_ctl, io_ctl->index - 1);
 571	else
 572		io_ctl_unmap_page(io_ctl);
 573
 574	while (io_ctl->index < io_ctl->num_pages) {
 575		io_ctl_map_page(io_ctl, 1);
 576		io_ctl_set_crc(io_ctl, io_ctl->index - 1);
 577	}
 578}
 579
 580static int io_ctl_read_entry(struct btrfs_io_ctl *io_ctl,
 581			    struct btrfs_free_space *entry, u8 *type)
 582{
 583	struct btrfs_free_space_entry *e;
 584	int ret;
 585
 586	if (!io_ctl->cur) {
 587		ret = io_ctl_check_crc(io_ctl, io_ctl->index);
 588		if (ret)
 589			return ret;
 590	}
 591
 592	e = io_ctl->cur;
 593	entry->offset = le64_to_cpu(e->offset);
 594	entry->bytes = le64_to_cpu(e->bytes);
 595	*type = e->type;
 596	io_ctl->cur += sizeof(struct btrfs_free_space_entry);
 597	io_ctl->size -= sizeof(struct btrfs_free_space_entry);
 598
 599	if (io_ctl->size >= sizeof(struct btrfs_free_space_entry))
 600		return 0;
 601
 602	io_ctl_unmap_page(io_ctl);
 603
 604	return 0;
 605}
 606
 607static int io_ctl_read_bitmap(struct btrfs_io_ctl *io_ctl,
 608			      struct btrfs_free_space *entry)
 609{
 610	int ret;
 611
 612	ret = io_ctl_check_crc(io_ctl, io_ctl->index);
 613	if (ret)
 614		return ret;
 615
 616	copy_page(entry->bitmap, io_ctl->cur);
 617	io_ctl_unmap_page(io_ctl);
 618
 619	return 0;
 620}
 621
 622/*
 623 * Since we attach pinned extents after the fact we can have contiguous sections
 624 * of free space that are split up in entries.  This poses a problem with the
 625 * tree logging stuff since it could have allocated across what appears to be 2
 626 * entries since we would have merged the entries when adding the pinned extents
 627 * back to the free space cache.  So run through the space cache that we just
 628 * loaded and merge contiguous entries.  This will make the log replay stuff not
 629 * blow up and it will make for nicer allocator behavior.
 630 */
 631static void merge_space_tree(struct btrfs_free_space_ctl *ctl)
 632{
 633	struct btrfs_free_space *e, *prev = NULL;
 634	struct rb_node *n;
 635
 636again:
 637	spin_lock(&ctl->tree_lock);
 638	for (n = rb_first(&ctl->free_space_offset); n; n = rb_next(n)) {
 639		e = rb_entry(n, struct btrfs_free_space, offset_index);
 640		if (!prev)
 641			goto next;
 642		if (e->bitmap || prev->bitmap)
 643			goto next;
 644		if (prev->offset + prev->bytes == e->offset) {
 645			unlink_free_space(ctl, prev);
 646			unlink_free_space(ctl, e);
 647			prev->bytes += e->bytes;
 648			kmem_cache_free(btrfs_free_space_cachep, e);
 649			link_free_space(ctl, prev);
 650			prev = NULL;
 651			spin_unlock(&ctl->tree_lock);
 652			goto again;
 653		}
 654next:
 655		prev = e;
 656	}
 657	spin_unlock(&ctl->tree_lock);
 658}
 659
 660static int __load_free_space_cache(struct btrfs_root *root, struct inode *inode,
 661				   struct btrfs_free_space_ctl *ctl,
 662				   struct btrfs_path *path, u64 offset)
 663{
 664	struct btrfs_fs_info *fs_info = root->fs_info;
 665	struct btrfs_free_space_header *header;
 666	struct extent_buffer *leaf;
 667	struct btrfs_io_ctl io_ctl;
 668	struct btrfs_key key;
 669	struct btrfs_free_space *e, *n;
 670	LIST_HEAD(bitmaps);
 671	u64 num_entries;
 672	u64 num_bitmaps;
 673	u64 generation;
 674	u8 type;
 675	int ret = 0;
 676
 677	/* Nothing in the space cache, goodbye */
 678	if (!i_size_read(inode))
 679		return 0;
 680
 681	key.objectid = BTRFS_FREE_SPACE_OBJECTID;
 682	key.offset = offset;
 683	key.type = 0;
 684
 685	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
 686	if (ret < 0)
 687		return 0;
 688	else if (ret > 0) {
 689		btrfs_release_path(path);
 690		return 0;
 691	}
 692
 693	ret = -1;
 694
 695	leaf = path->nodes[0];
 696	header = btrfs_item_ptr(leaf, path->slots[0],
 697				struct btrfs_free_space_header);
 698	num_entries = btrfs_free_space_entries(leaf, header);
 699	num_bitmaps = btrfs_free_space_bitmaps(leaf, header);
 700	generation = btrfs_free_space_generation(leaf, header);
 701	btrfs_release_path(path);
 702
 703	if (!BTRFS_I(inode)->generation) {
 704		btrfs_info(fs_info,
 705			   "the free space cache file (%llu) is invalid, skip it",
 706			   offset);
 707		return 0;
 708	}
 709
 710	if (BTRFS_I(inode)->generation != generation) {
 711		btrfs_err(fs_info,
 712			  "free space inode generation (%llu) did not match free space cache generation (%llu)",
 713			  BTRFS_I(inode)->generation, generation);
 714		return 0;
 715	}
 716
 717	if (!num_entries)
 718		return 0;
 719
 720	ret = io_ctl_init(&io_ctl, inode, 0);
 721	if (ret)
 722		return ret;
 723
 724	readahead_cache(inode);
 
 
 725
 726	ret = io_ctl_prepare_pages(&io_ctl, inode, 1);
 727	if (ret)
 728		goto out;
 729
 730	ret = io_ctl_check_crc(&io_ctl, 0);
 731	if (ret)
 732		goto free_cache;
 733
 734	ret = io_ctl_check_generation(&io_ctl, generation);
 735	if (ret)
 736		goto free_cache;
 737
 738	while (num_entries) {
 739		e = kmem_cache_zalloc(btrfs_free_space_cachep,
 740				      GFP_NOFS);
 741		if (!e)
 742			goto free_cache;
 743
 744		ret = io_ctl_read_entry(&io_ctl, e, &type);
 745		if (ret) {
 746			kmem_cache_free(btrfs_free_space_cachep, e);
 747			goto free_cache;
 748		}
 749
 750		if (!e->bytes) {
 751			kmem_cache_free(btrfs_free_space_cachep, e);
 752			goto free_cache;
 753		}
 754
 755		if (type == BTRFS_FREE_SPACE_EXTENT) {
 756			spin_lock(&ctl->tree_lock);
 757			ret = link_free_space(ctl, e);
 758			spin_unlock(&ctl->tree_lock);
 759			if (ret) {
 760				btrfs_err(fs_info,
 761					"Duplicate entries in free space cache, dumping");
 762				kmem_cache_free(btrfs_free_space_cachep, e);
 763				goto free_cache;
 764			}
 765		} else {
 766			ASSERT(num_bitmaps);
 767			num_bitmaps--;
 768			e->bitmap = kmem_cache_zalloc(
 769					btrfs_free_space_bitmap_cachep, GFP_NOFS);
 770			if (!e->bitmap) {
 771				kmem_cache_free(
 772					btrfs_free_space_cachep, e);
 773				goto free_cache;
 774			}
 775			spin_lock(&ctl->tree_lock);
 776			ret = link_free_space(ctl, e);
 777			ctl->total_bitmaps++;
 778			ctl->op->recalc_thresholds(ctl);
 779			spin_unlock(&ctl->tree_lock);
 780			if (ret) {
 781				btrfs_err(fs_info,
 782					"Duplicate entries in free space cache, dumping");
 783				kmem_cache_free(btrfs_free_space_cachep, e);
 784				goto free_cache;
 785			}
 786			list_add_tail(&e->list, &bitmaps);
 787		}
 788
 789		num_entries--;
 790	}
 791
 792	io_ctl_unmap_page(&io_ctl);
 793
 794	/*
 795	 * We add the bitmaps at the end of the entries in order that
 796	 * the bitmap entries are added to the cache.
 797	 */
 798	list_for_each_entry_safe(e, n, &bitmaps, list) {
 799		list_del_init(&e->list);
 800		ret = io_ctl_read_bitmap(&io_ctl, e);
 801		if (ret)
 802			goto free_cache;
 803	}
 804
 805	io_ctl_drop_pages(&io_ctl);
 806	merge_space_tree(ctl);
 807	ret = 1;
 808out:
 809	io_ctl_free(&io_ctl);
 810	return ret;
 811free_cache:
 812	io_ctl_drop_pages(&io_ctl);
 813	__btrfs_remove_free_space_cache(ctl);
 814	goto out;
 815}
 816
 817int load_free_space_cache(struct btrfs_block_group_cache *block_group)
 
 818{
 819	struct btrfs_fs_info *fs_info = block_group->fs_info;
 820	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
 
 821	struct inode *inode;
 822	struct btrfs_path *path;
 823	int ret = 0;
 824	bool matched;
 825	u64 used = btrfs_block_group_used(&block_group->item);
 826
 827	/*
 828	 * If this block group has been marked to be cleared for one reason or
 829	 * another then we can't trust the on disk cache, so just return.
 830	 */
 831	spin_lock(&block_group->lock);
 832	if (block_group->disk_cache_state != BTRFS_DC_WRITTEN) {
 833		spin_unlock(&block_group->lock);
 834		return 0;
 835	}
 836	spin_unlock(&block_group->lock);
 837
 838	path = btrfs_alloc_path();
 839	if (!path)
 840		return 0;
 841	path->search_commit_root = 1;
 842	path->skip_locking = 1;
 843
 844	/*
 845	 * We must pass a path with search_commit_root set to btrfs_iget in
 846	 * order to avoid a deadlock when allocating extents for the tree root.
 847	 *
 848	 * When we are COWing an extent buffer from the tree root, when looking
 849	 * for a free extent, at extent-tree.c:find_free_extent(), we can find
 850	 * block group without its free space cache loaded. When we find one
 851	 * we must load its space cache which requires reading its free space
 852	 * cache's inode item from the root tree. If this inode item is located
 853	 * in the same leaf that we started COWing before, then we end up in
 854	 * deadlock on the extent buffer (trying to read lock it when we
 855	 * previously write locked it).
 856	 *
 857	 * It's safe to read the inode item using the commit root because
 858	 * block groups, once loaded, stay in memory forever (until they are
 859	 * removed) as well as their space caches once loaded. New block groups
 860	 * once created get their ->cached field set to BTRFS_CACHE_FINISHED so
 861	 * we will never try to read their inode item while the fs is mounted.
 862	 */
 863	inode = lookup_free_space_inode(block_group, path);
 864	if (IS_ERR(inode)) {
 865		btrfs_free_path(path);
 866		return 0;
 867	}
 868
 869	/* We may have converted the inode and made the cache invalid. */
 870	spin_lock(&block_group->lock);
 871	if (block_group->disk_cache_state != BTRFS_DC_WRITTEN) {
 872		spin_unlock(&block_group->lock);
 873		btrfs_free_path(path);
 874		goto out;
 875	}
 876	spin_unlock(&block_group->lock);
 877
 878	ret = __load_free_space_cache(fs_info->tree_root, inode, ctl,
 879				      path, block_group->key.objectid);
 880	btrfs_free_path(path);
 881	if (ret <= 0)
 882		goto out;
 883
 884	spin_lock(&ctl->tree_lock);
 885	matched = (ctl->free_space == (block_group->key.offset - used -
 886				       block_group->bytes_super));
 887	spin_unlock(&ctl->tree_lock);
 888
 889	if (!matched) {
 890		__btrfs_remove_free_space_cache(ctl);
 891		btrfs_warn(fs_info,
 892			   "block group %llu has wrong amount of free space",
 893			   block_group->key.objectid);
 894		ret = -1;
 895	}
 896out:
 897	if (ret < 0) {
 898		/* This cache is bogus, make sure it gets cleared */
 899		spin_lock(&block_group->lock);
 900		block_group->disk_cache_state = BTRFS_DC_CLEAR;
 901		spin_unlock(&block_group->lock);
 902		ret = 0;
 903
 904		btrfs_warn(fs_info,
 905			   "failed to load free space cache for block group %llu, rebuilding it now",
 906			   block_group->key.objectid);
 907	}
 908
 909	iput(inode);
 910	return ret;
 911}
 912
 913static noinline_for_stack
 914int write_cache_extent_entries(struct btrfs_io_ctl *io_ctl,
 915			      struct btrfs_free_space_ctl *ctl,
 916			      struct btrfs_block_group_cache *block_group,
 917			      int *entries, int *bitmaps,
 918			      struct list_head *bitmap_list)
 919{
 920	int ret;
 921	struct btrfs_free_cluster *cluster = NULL;
 922	struct btrfs_free_cluster *cluster_locked = NULL;
 923	struct rb_node *node = rb_first(&ctl->free_space_offset);
 924	struct btrfs_trim_range *trim_entry;
 925
 926	/* Get the cluster for this block_group if it exists */
 927	if (block_group && !list_empty(&block_group->cluster_list)) {
 928		cluster = list_entry(block_group->cluster_list.next,
 929				     struct btrfs_free_cluster,
 930				     block_group_list);
 931	}
 932
 933	if (!node && cluster) {
 934		cluster_locked = cluster;
 935		spin_lock(&cluster_locked->lock);
 936		node = rb_first(&cluster->root);
 937		cluster = NULL;
 938	}
 939
 940	/* Write out the extent entries */
 941	while (node) {
 942		struct btrfs_free_space *e;
 943
 944		e = rb_entry(node, struct btrfs_free_space, offset_index);
 945		*entries += 1;
 946
 947		ret = io_ctl_add_entry(io_ctl, e->offset, e->bytes,
 948				       e->bitmap);
 949		if (ret)
 950			goto fail;
 951
 952		if (e->bitmap) {
 953			list_add_tail(&e->list, bitmap_list);
 954			*bitmaps += 1;
 955		}
 956		node = rb_next(node);
 957		if (!node && cluster) {
 958			node = rb_first(&cluster->root);
 959			cluster_locked = cluster;
 960			spin_lock(&cluster_locked->lock);
 961			cluster = NULL;
 962		}
 963	}
 964	if (cluster_locked) {
 965		spin_unlock(&cluster_locked->lock);
 966		cluster_locked = NULL;
 967	}
 968
 969	/*
 970	 * Make sure we don't miss any range that was removed from our rbtree
 971	 * because trimming is running. Otherwise after a umount+mount (or crash
 972	 * after committing the transaction) we would leak free space and get
 973	 * an inconsistent free space cache report from fsck.
 974	 */
 975	list_for_each_entry(trim_entry, &ctl->trimming_ranges, list) {
 976		ret = io_ctl_add_entry(io_ctl, trim_entry->start,
 977				       trim_entry->bytes, NULL);
 978		if (ret)
 979			goto fail;
 980		*entries += 1;
 981	}
 982
 983	return 0;
 984fail:
 985	if (cluster_locked)
 986		spin_unlock(&cluster_locked->lock);
 987	return -ENOSPC;
 988}
 989
 990static noinline_for_stack int
 991update_cache_item(struct btrfs_trans_handle *trans,
 992		  struct btrfs_root *root,
 993		  struct inode *inode,
 994		  struct btrfs_path *path, u64 offset,
 995		  int entries, int bitmaps)
 996{
 997	struct btrfs_key key;
 998	struct btrfs_free_space_header *header;
 999	struct extent_buffer *leaf;
1000	int ret;
1001
1002	key.objectid = BTRFS_FREE_SPACE_OBJECTID;
1003	key.offset = offset;
1004	key.type = 0;
1005
1006	ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
1007	if (ret < 0) {
1008		clear_extent_bit(&BTRFS_I(inode)->io_tree, 0, inode->i_size - 1,
1009				 EXTENT_DELALLOC, 0, 0, NULL);
 
1010		goto fail;
1011	}
1012	leaf = path->nodes[0];
1013	if (ret > 0) {
1014		struct btrfs_key found_key;
1015		ASSERT(path->slots[0]);
1016		path->slots[0]--;
1017		btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
1018		if (found_key.objectid != BTRFS_FREE_SPACE_OBJECTID ||
1019		    found_key.offset != offset) {
1020			clear_extent_bit(&BTRFS_I(inode)->io_tree, 0,
1021					 inode->i_size - 1, EXTENT_DELALLOC, 0,
1022					 0, NULL);
 
1023			btrfs_release_path(path);
1024			goto fail;
1025		}
1026	}
1027
1028	BTRFS_I(inode)->generation = trans->transid;
1029	header = btrfs_item_ptr(leaf, path->slots[0],
1030				struct btrfs_free_space_header);
1031	btrfs_set_free_space_entries(leaf, header, entries);
1032	btrfs_set_free_space_bitmaps(leaf, header, bitmaps);
1033	btrfs_set_free_space_generation(leaf, header, trans->transid);
1034	btrfs_mark_buffer_dirty(leaf);
1035	btrfs_release_path(path);
1036
1037	return 0;
1038
1039fail:
1040	return -1;
1041}
1042
1043static noinline_for_stack int write_pinned_extent_entries(
 
1044			    struct btrfs_block_group_cache *block_group,
1045			    struct btrfs_io_ctl *io_ctl,
1046			    int *entries)
1047{
1048	u64 start, extent_start, extent_end, len;
1049	struct extent_io_tree *unpin = NULL;
1050	int ret;
1051
1052	if (!block_group)
1053		return 0;
1054
1055	/*
1056	 * We want to add any pinned extents to our free space cache
1057	 * so we don't leak the space
1058	 *
1059	 * We shouldn't have switched the pinned extents yet so this is the
1060	 * right one
1061	 */
1062	unpin = block_group->fs_info->pinned_extents;
1063
1064	start = block_group->key.objectid;
1065
1066	while (start < block_group->key.objectid + block_group->key.offset) {
1067		ret = find_first_extent_bit(unpin, start,
1068					    &extent_start, &extent_end,
1069					    EXTENT_DIRTY, NULL);
1070		if (ret)
1071			return 0;
1072
1073		/* This pinned extent is out of our range */
1074		if (extent_start >= block_group->key.objectid +
1075		    block_group->key.offset)
1076			return 0;
1077
1078		extent_start = max(extent_start, start);
1079		extent_end = min(block_group->key.objectid +
1080				 block_group->key.offset, extent_end + 1);
1081		len = extent_end - extent_start;
1082
1083		*entries += 1;
1084		ret = io_ctl_add_entry(io_ctl, extent_start, len, NULL);
1085		if (ret)
1086			return -ENOSPC;
1087
1088		start = extent_end;
1089	}
1090
1091	return 0;
1092}
1093
1094static noinline_for_stack int
1095write_bitmap_entries(struct btrfs_io_ctl *io_ctl, struct list_head *bitmap_list)
1096{
1097	struct btrfs_free_space *entry, *next;
1098	int ret;
1099
1100	/* Write out the bitmaps */
1101	list_for_each_entry_safe(entry, next, bitmap_list, list) {
1102		ret = io_ctl_add_bitmap(io_ctl, entry->bitmap);
1103		if (ret)
1104			return -ENOSPC;
1105		list_del_init(&entry->list);
1106	}
1107
1108	return 0;
1109}
1110
1111static int flush_dirty_cache(struct inode *inode)
1112{
1113	int ret;
1114
1115	ret = btrfs_wait_ordered_range(inode, 0, (u64)-1);
1116	if (ret)
1117		clear_extent_bit(&BTRFS_I(inode)->io_tree, 0, inode->i_size - 1,
1118				 EXTENT_DELALLOC, 0, 0, NULL);
 
1119
1120	return ret;
1121}
1122
1123static void noinline_for_stack
1124cleanup_bitmap_list(struct list_head *bitmap_list)
1125{
1126	struct btrfs_free_space *entry, *next;
1127
1128	list_for_each_entry_safe(entry, next, bitmap_list, list)
1129		list_del_init(&entry->list);
1130}
1131
1132static void noinline_for_stack
1133cleanup_write_cache_enospc(struct inode *inode,
1134			   struct btrfs_io_ctl *io_ctl,
1135			   struct extent_state **cached_state)
 
1136{
1137	io_ctl_drop_pages(io_ctl);
1138	unlock_extent_cached(&BTRFS_I(inode)->io_tree, 0,
1139			     i_size_read(inode) - 1, cached_state);
 
1140}
1141
1142static int __btrfs_wait_cache_io(struct btrfs_root *root,
1143				 struct btrfs_trans_handle *trans,
1144				 struct btrfs_block_group_cache *block_group,
1145				 struct btrfs_io_ctl *io_ctl,
1146				 struct btrfs_path *path, u64 offset)
1147{
1148	int ret;
1149	struct inode *inode = io_ctl->inode;
 
1150
1151	if (!inode)
1152		return 0;
1153
 
 
1154	/* Flush the dirty pages in the cache file. */
1155	ret = flush_dirty_cache(inode);
1156	if (ret)
1157		goto out;
1158
1159	/* Update the cache item to tell everyone this cache file is valid. */
1160	ret = update_cache_item(trans, root, inode, path, offset,
1161				io_ctl->entries, io_ctl->bitmaps);
1162out:
1163	io_ctl_free(io_ctl);
1164	if (ret) {
1165		invalidate_inode_pages2(inode->i_mapping);
1166		BTRFS_I(inode)->generation = 0;
1167		if (block_group) {
1168#ifdef DEBUG
1169			btrfs_err(root->fs_info,
1170				  "failed to write free space cache for block group %llu",
1171				  block_group->key.objectid);
1172#endif
1173		}
1174	}
1175	btrfs_update_inode(trans, root, inode);
1176
1177	if (block_group) {
1178		/* the dirty list is protected by the dirty_bgs_lock */
1179		spin_lock(&trans->transaction->dirty_bgs_lock);
1180
1181		/* the disk_cache_state is protected by the block group lock */
1182		spin_lock(&block_group->lock);
1183
1184		/*
1185		 * only mark this as written if we didn't get put back on
1186		 * the dirty list while waiting for IO.   Otherwise our
1187		 * cache state won't be right, and we won't get written again
1188		 */
1189		if (!ret && list_empty(&block_group->dirty_list))
1190			block_group->disk_cache_state = BTRFS_DC_WRITTEN;
1191		else if (ret)
1192			block_group->disk_cache_state = BTRFS_DC_ERROR;
1193
1194		spin_unlock(&block_group->lock);
1195		spin_unlock(&trans->transaction->dirty_bgs_lock);
1196		io_ctl->inode = NULL;
1197		iput(inode);
1198	}
1199
1200	return ret;
1201
1202}
1203
1204static int btrfs_wait_cache_io_root(struct btrfs_root *root,
1205				    struct btrfs_trans_handle *trans,
1206				    struct btrfs_io_ctl *io_ctl,
1207				    struct btrfs_path *path)
1208{
1209	return __btrfs_wait_cache_io(root, trans, NULL, io_ctl, path, 0);
1210}
1211
1212int btrfs_wait_cache_io(struct btrfs_trans_handle *trans,
1213			struct btrfs_block_group_cache *block_group,
1214			struct btrfs_path *path)
1215{
1216	return __btrfs_wait_cache_io(block_group->fs_info->tree_root, trans,
1217				     block_group, &block_group->io_ctl,
1218				     path, block_group->key.objectid);
1219}
1220
1221/**
1222 * __btrfs_write_out_cache - write out cached info to an inode
1223 * @root - the root the inode belongs to
1224 * @ctl - the free space cache we are going to write out
1225 * @block_group - the block_group for this cache if it belongs to a block_group
1226 * @trans - the trans handle
 
 
1227 *
1228 * This function writes out a free space cache struct to disk for quick recovery
1229 * on mount.  This will return 0 if it was successful in writing the cache out,
1230 * or an errno if it was not.
1231 */
1232static int __btrfs_write_out_cache(struct btrfs_root *root, struct inode *inode,
1233				   struct btrfs_free_space_ctl *ctl,
1234				   struct btrfs_block_group_cache *block_group,
1235				   struct btrfs_io_ctl *io_ctl,
1236				   struct btrfs_trans_handle *trans)
 
1237{
 
1238	struct extent_state *cached_state = NULL;
1239	LIST_HEAD(bitmap_list);
1240	int entries = 0;
1241	int bitmaps = 0;
1242	int ret;
1243	int must_iput = 0;
1244
1245	if (!i_size_read(inode))
1246		return -EIO;
1247
1248	WARN_ON(io_ctl->pages);
1249	ret = io_ctl_init(io_ctl, inode, 1);
1250	if (ret)
1251		return ret;
1252
1253	if (block_group && (block_group->flags & BTRFS_BLOCK_GROUP_DATA)) {
1254		down_write(&block_group->data_rwsem);
1255		spin_lock(&block_group->lock);
1256		if (block_group->delalloc_bytes) {
1257			block_group->disk_cache_state = BTRFS_DC_WRITTEN;
1258			spin_unlock(&block_group->lock);
1259			up_write(&block_group->data_rwsem);
1260			BTRFS_I(inode)->generation = 0;
1261			ret = 0;
1262			must_iput = 1;
1263			goto out;
1264		}
1265		spin_unlock(&block_group->lock);
1266	}
1267
1268	/* Lock all pages first so we can lock the extent safely. */
1269	ret = io_ctl_prepare_pages(io_ctl, inode, 0);
1270	if (ret)
1271		goto out_unlock;
1272
1273	lock_extent_bits(&BTRFS_I(inode)->io_tree, 0, i_size_read(inode) - 1,
1274			 &cached_state);
1275
1276	io_ctl_set_generation(io_ctl, trans->transid);
1277
1278	mutex_lock(&ctl->cache_writeout_mutex);
1279	/* Write out the extent entries in the free space cache */
1280	spin_lock(&ctl->tree_lock);
1281	ret = write_cache_extent_entries(io_ctl, ctl,
1282					 block_group, &entries, &bitmaps,
1283					 &bitmap_list);
1284	if (ret)
1285		goto out_nospc_locked;
1286
1287	/*
1288	 * Some spaces that are freed in the current transaction are pinned,
1289	 * they will be added into free space cache after the transaction is
1290	 * committed, we shouldn't lose them.
1291	 *
1292	 * If this changes while we are working we'll get added back to
1293	 * the dirty list and redo it.  No locking needed
1294	 */
1295	ret = write_pinned_extent_entries(block_group, io_ctl, &entries);
 
1296	if (ret)
1297		goto out_nospc_locked;
1298
1299	/*
1300	 * At last, we write out all the bitmaps and keep cache_writeout_mutex
1301	 * locked while doing it because a concurrent trim can be manipulating
1302	 * or freeing the bitmap.
1303	 */
1304	ret = write_bitmap_entries(io_ctl, &bitmap_list);
1305	spin_unlock(&ctl->tree_lock);
1306	mutex_unlock(&ctl->cache_writeout_mutex);
1307	if (ret)
1308		goto out_nospc;
1309
1310	/* Zero out the rest of the pages just to make sure */
1311	io_ctl_zero_remaining_pages(io_ctl);
1312
1313	/* Everything is written out, now we dirty the pages in the file. */
1314	ret = btrfs_dirty_pages(inode, io_ctl->pages, io_ctl->num_pages, 0,
1315				i_size_read(inode), &cached_state);
1316	if (ret)
1317		goto out_nospc;
1318
1319	if (block_group && (block_group->flags & BTRFS_BLOCK_GROUP_DATA))
1320		up_write(&block_group->data_rwsem);
1321	/*
1322	 * Release the pages and unlock the extent, we will flush
1323	 * them out later
1324	 */
1325	io_ctl_drop_pages(io_ctl);
1326
1327	unlock_extent_cached(&BTRFS_I(inode)->io_tree, 0,
1328			     i_size_read(inode) - 1, &cached_state);
1329
1330	/*
1331	 * at this point the pages are under IO and we're happy,
1332	 * The caller is responsible for waiting on them and updating the
1333	 * the cache and the inode
1334	 */
1335	io_ctl->entries = entries;
1336	io_ctl->bitmaps = bitmaps;
1337
1338	ret = btrfs_fdatawrite_range(inode, 0, (u64)-1);
1339	if (ret)
1340		goto out;
1341
1342	return 0;
1343
1344out:
1345	io_ctl->inode = NULL;
1346	io_ctl_free(io_ctl);
1347	if (ret) {
1348		invalidate_inode_pages2(inode->i_mapping);
1349		BTRFS_I(inode)->generation = 0;
1350	}
1351	btrfs_update_inode(trans, root, inode);
1352	if (must_iput)
1353		iput(inode);
1354	return ret;
1355
1356out_nospc_locked:
1357	cleanup_bitmap_list(&bitmap_list);
1358	spin_unlock(&ctl->tree_lock);
1359	mutex_unlock(&ctl->cache_writeout_mutex);
1360
1361out_nospc:
1362	cleanup_write_cache_enospc(inode, io_ctl, &cached_state);
1363
1364out_unlock:
1365	if (block_group && (block_group->flags & BTRFS_BLOCK_GROUP_DATA))
1366		up_write(&block_group->data_rwsem);
1367
1368	goto out;
1369}
1370
1371int btrfs_write_out_cache(struct btrfs_trans_handle *trans,
 
1372			  struct btrfs_block_group_cache *block_group,
1373			  struct btrfs_path *path)
1374{
1375	struct btrfs_fs_info *fs_info = trans->fs_info;
1376	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
1377	struct inode *inode;
1378	int ret = 0;
1379
1380	spin_lock(&block_group->lock);
1381	if (block_group->disk_cache_state < BTRFS_DC_SETUP) {
1382		spin_unlock(&block_group->lock);
1383		return 0;
1384	}
1385	spin_unlock(&block_group->lock);
1386
1387	inode = lookup_free_space_inode(block_group, path);
1388	if (IS_ERR(inode))
1389		return 0;
1390
1391	ret = __btrfs_write_out_cache(fs_info->tree_root, inode, ctl,
1392				block_group, &block_group->io_ctl, trans);
 
1393	if (ret) {
1394#ifdef DEBUG
1395		btrfs_err(fs_info,
1396			  "failed to write free space cache for block group %llu",
1397			  block_group->key.objectid);
1398#endif
1399		spin_lock(&block_group->lock);
1400		block_group->disk_cache_state = BTRFS_DC_ERROR;
1401		spin_unlock(&block_group->lock);
1402
1403		block_group->io_ctl.inode = NULL;
1404		iput(inode);
1405	}
1406
1407	/*
1408	 * if ret == 0 the caller is expected to call btrfs_wait_cache_io
1409	 * to wait for IO and put the inode
1410	 */
1411
1412	return ret;
1413}
1414
1415static inline unsigned long offset_to_bit(u64 bitmap_start, u32 unit,
1416					  u64 offset)
1417{
1418	ASSERT(offset >= bitmap_start);
1419	offset -= bitmap_start;
1420	return (unsigned long)(div_u64(offset, unit));
1421}
1422
1423static inline unsigned long bytes_to_bits(u64 bytes, u32 unit)
1424{
1425	return (unsigned long)(div_u64(bytes, unit));
1426}
1427
1428static inline u64 offset_to_bitmap(struct btrfs_free_space_ctl *ctl,
1429				   u64 offset)
1430{
1431	u64 bitmap_start;
1432	u64 bytes_per_bitmap;
1433
1434	bytes_per_bitmap = BITS_PER_BITMAP * ctl->unit;
1435	bitmap_start = offset - ctl->start;
1436	bitmap_start = div64_u64(bitmap_start, bytes_per_bitmap);
1437	bitmap_start *= bytes_per_bitmap;
1438	bitmap_start += ctl->start;
1439
1440	return bitmap_start;
1441}
1442
1443static int tree_insert_offset(struct rb_root *root, u64 offset,
1444			      struct rb_node *node, int bitmap)
1445{
1446	struct rb_node **p = &root->rb_node;
1447	struct rb_node *parent = NULL;
1448	struct btrfs_free_space *info;
1449
1450	while (*p) {
1451		parent = *p;
1452		info = rb_entry(parent, struct btrfs_free_space, offset_index);
1453
1454		if (offset < info->offset) {
1455			p = &(*p)->rb_left;
1456		} else if (offset > info->offset) {
1457			p = &(*p)->rb_right;
1458		} else {
1459			/*
1460			 * we could have a bitmap entry and an extent entry
1461			 * share the same offset.  If this is the case, we want
1462			 * the extent entry to always be found first if we do a
1463			 * linear search through the tree, since we want to have
1464			 * the quickest allocation time, and allocating from an
1465			 * extent is faster than allocating from a bitmap.  So
1466			 * if we're inserting a bitmap and we find an entry at
1467			 * this offset, we want to go right, or after this entry
1468			 * logically.  If we are inserting an extent and we've
1469			 * found a bitmap, we want to go left, or before
1470			 * logically.
1471			 */
1472			if (bitmap) {
1473				if (info->bitmap) {
1474					WARN_ON_ONCE(1);
1475					return -EEXIST;
1476				}
1477				p = &(*p)->rb_right;
1478			} else {
1479				if (!info->bitmap) {
1480					WARN_ON_ONCE(1);
1481					return -EEXIST;
1482				}
1483				p = &(*p)->rb_left;
1484			}
1485		}
1486	}
1487
1488	rb_link_node(node, parent, p);
1489	rb_insert_color(node, root);
1490
1491	return 0;
1492}
1493
1494/*
1495 * searches the tree for the given offset.
1496 *
1497 * fuzzy - If this is set, then we are trying to make an allocation, and we just
1498 * want a section that has at least bytes size and comes at or after the given
1499 * offset.
1500 */
1501static struct btrfs_free_space *
1502tree_search_offset(struct btrfs_free_space_ctl *ctl,
1503		   u64 offset, int bitmap_only, int fuzzy)
1504{
1505	struct rb_node *n = ctl->free_space_offset.rb_node;
1506	struct btrfs_free_space *entry, *prev = NULL;
1507
1508	/* find entry that is closest to the 'offset' */
1509	while (1) {
1510		if (!n) {
1511			entry = NULL;
1512			break;
1513		}
1514
1515		entry = rb_entry(n, struct btrfs_free_space, offset_index);
1516		prev = entry;
1517
1518		if (offset < entry->offset)
1519			n = n->rb_left;
1520		else if (offset > entry->offset)
1521			n = n->rb_right;
1522		else
1523			break;
1524	}
1525
1526	if (bitmap_only) {
1527		if (!entry)
1528			return NULL;
1529		if (entry->bitmap)
1530			return entry;
1531
1532		/*
1533		 * bitmap entry and extent entry may share same offset,
1534		 * in that case, bitmap entry comes after extent entry.
1535		 */
1536		n = rb_next(n);
1537		if (!n)
1538			return NULL;
1539		entry = rb_entry(n, struct btrfs_free_space, offset_index);
1540		if (entry->offset != offset)
1541			return NULL;
1542
1543		WARN_ON(!entry->bitmap);
1544		return entry;
1545	} else if (entry) {
1546		if (entry->bitmap) {
1547			/*
1548			 * if previous extent entry covers the offset,
1549			 * we should return it instead of the bitmap entry
1550			 */
1551			n = rb_prev(&entry->offset_index);
1552			if (n) {
1553				prev = rb_entry(n, struct btrfs_free_space,
1554						offset_index);
1555				if (!prev->bitmap &&
1556				    prev->offset + prev->bytes > offset)
1557					entry = prev;
1558			}
1559		}
1560		return entry;
1561	}
1562
1563	if (!prev)
1564		return NULL;
1565
1566	/* find last entry before the 'offset' */
1567	entry = prev;
1568	if (entry->offset > offset) {
1569		n = rb_prev(&entry->offset_index);
1570		if (n) {
1571			entry = rb_entry(n, struct btrfs_free_space,
1572					offset_index);
1573			ASSERT(entry->offset <= offset);
1574		} else {
1575			if (fuzzy)
1576				return entry;
1577			else
1578				return NULL;
1579		}
1580	}
1581
1582	if (entry->bitmap) {
1583		n = rb_prev(&entry->offset_index);
1584		if (n) {
1585			prev = rb_entry(n, struct btrfs_free_space,
1586					offset_index);
1587			if (!prev->bitmap &&
1588			    prev->offset + prev->bytes > offset)
1589				return prev;
1590		}
1591		if (entry->offset + BITS_PER_BITMAP * ctl->unit > offset)
1592			return entry;
1593	} else if (entry->offset + entry->bytes > offset)
1594		return entry;
1595
1596	if (!fuzzy)
1597		return NULL;
1598
1599	while (1) {
1600		if (entry->bitmap) {
1601			if (entry->offset + BITS_PER_BITMAP *
1602			    ctl->unit > offset)
1603				break;
1604		} else {
1605			if (entry->offset + entry->bytes > offset)
1606				break;
1607		}
1608
1609		n = rb_next(&entry->offset_index);
1610		if (!n)
1611			return NULL;
1612		entry = rb_entry(n, struct btrfs_free_space, offset_index);
1613	}
1614	return entry;
1615}
1616
1617static inline void
1618__unlink_free_space(struct btrfs_free_space_ctl *ctl,
1619		    struct btrfs_free_space *info)
1620{
1621	rb_erase(&info->offset_index, &ctl->free_space_offset);
1622	ctl->free_extents--;
1623}
1624
1625static void unlink_free_space(struct btrfs_free_space_ctl *ctl,
1626			      struct btrfs_free_space *info)
1627{
1628	__unlink_free_space(ctl, info);
1629	ctl->free_space -= info->bytes;
1630}
1631
1632static int link_free_space(struct btrfs_free_space_ctl *ctl,
1633			   struct btrfs_free_space *info)
1634{
1635	int ret = 0;
1636
1637	ASSERT(info->bytes || info->bitmap);
1638	ret = tree_insert_offset(&ctl->free_space_offset, info->offset,
1639				 &info->offset_index, (info->bitmap != NULL));
1640	if (ret)
1641		return ret;
1642
1643	ctl->free_space += info->bytes;
1644	ctl->free_extents++;
1645	return ret;
1646}
1647
1648static void recalculate_thresholds(struct btrfs_free_space_ctl *ctl)
1649{
1650	struct btrfs_block_group_cache *block_group = ctl->private;
1651	u64 max_bytes;
1652	u64 bitmap_bytes;
1653	u64 extent_bytes;
1654	u64 size = block_group->key.offset;
1655	u64 bytes_per_bg = BITS_PER_BITMAP * ctl->unit;
1656	u64 max_bitmaps = div64_u64(size + bytes_per_bg - 1, bytes_per_bg);
1657
1658	max_bitmaps = max_t(u64, max_bitmaps, 1);
1659
1660	ASSERT(ctl->total_bitmaps <= max_bitmaps);
1661
1662	/*
1663	 * The goal is to keep the total amount of memory used per 1gb of space
1664	 * at or below 32k, so we need to adjust how much memory we allow to be
1665	 * used by extent based free space tracking
1666	 */
1667	if (size < SZ_1G)
1668		max_bytes = MAX_CACHE_BYTES_PER_GIG;
1669	else
1670		max_bytes = MAX_CACHE_BYTES_PER_GIG * div_u64(size, SZ_1G);
1671
1672	/*
1673	 * we want to account for 1 more bitmap than what we have so we can make
1674	 * sure we don't go over our overall goal of MAX_CACHE_BYTES_PER_GIG as
1675	 * we add more bitmaps.
1676	 */
1677	bitmap_bytes = (ctl->total_bitmaps + 1) * ctl->unit;
1678
1679	if (bitmap_bytes >= max_bytes) {
1680		ctl->extents_thresh = 0;
1681		return;
1682	}
1683
1684	/*
1685	 * we want the extent entry threshold to always be at most 1/2 the max
1686	 * bytes we can have, or whatever is less than that.
1687	 */
1688	extent_bytes = max_bytes - bitmap_bytes;
1689	extent_bytes = min_t(u64, extent_bytes, max_bytes >> 1);
1690
1691	ctl->extents_thresh =
1692		div_u64(extent_bytes, sizeof(struct btrfs_free_space));
1693}
1694
1695static inline void __bitmap_clear_bits(struct btrfs_free_space_ctl *ctl,
1696				       struct btrfs_free_space *info,
1697				       u64 offset, u64 bytes)
1698{
1699	unsigned long start, count;
1700
1701	start = offset_to_bit(info->offset, ctl->unit, offset);
1702	count = bytes_to_bits(bytes, ctl->unit);
1703	ASSERT(start + count <= BITS_PER_BITMAP);
1704
1705	bitmap_clear(info->bitmap, start, count);
1706
1707	info->bytes -= bytes;
1708	if (info->max_extent_size > ctl->unit)
1709		info->max_extent_size = 0;
1710}
1711
1712static void bitmap_clear_bits(struct btrfs_free_space_ctl *ctl,
1713			      struct btrfs_free_space *info, u64 offset,
1714			      u64 bytes)
1715{
1716	__bitmap_clear_bits(ctl, info, offset, bytes);
1717	ctl->free_space -= bytes;
1718}
1719
1720static void bitmap_set_bits(struct btrfs_free_space_ctl *ctl,
1721			    struct btrfs_free_space *info, u64 offset,
1722			    u64 bytes)
1723{
1724	unsigned long start, count;
1725
1726	start = offset_to_bit(info->offset, ctl->unit, offset);
1727	count = bytes_to_bits(bytes, ctl->unit);
1728	ASSERT(start + count <= BITS_PER_BITMAP);
1729
1730	bitmap_set(info->bitmap, start, count);
1731
1732	info->bytes += bytes;
1733	ctl->free_space += bytes;
1734}
1735
1736/*
1737 * If we can not find suitable extent, we will use bytes to record
1738 * the size of the max extent.
1739 */
1740static int search_bitmap(struct btrfs_free_space_ctl *ctl,
1741			 struct btrfs_free_space *bitmap_info, u64 *offset,
1742			 u64 *bytes, bool for_alloc)
1743{
1744	unsigned long found_bits = 0;
1745	unsigned long max_bits = 0;
1746	unsigned long bits, i;
1747	unsigned long next_zero;
1748	unsigned long extent_bits;
1749
1750	/*
1751	 * Skip searching the bitmap if we don't have a contiguous section that
1752	 * is large enough for this allocation.
1753	 */
1754	if (for_alloc &&
1755	    bitmap_info->max_extent_size &&
1756	    bitmap_info->max_extent_size < *bytes) {
1757		*bytes = bitmap_info->max_extent_size;
1758		return -1;
1759	}
1760
1761	i = offset_to_bit(bitmap_info->offset, ctl->unit,
1762			  max_t(u64, *offset, bitmap_info->offset));
1763	bits = bytes_to_bits(*bytes, ctl->unit);
1764
1765	for_each_set_bit_from(i, bitmap_info->bitmap, BITS_PER_BITMAP) {
1766		if (for_alloc && bits == 1) {
1767			found_bits = 1;
1768			break;
1769		}
1770		next_zero = find_next_zero_bit(bitmap_info->bitmap,
1771					       BITS_PER_BITMAP, i);
1772		extent_bits = next_zero - i;
1773		if (extent_bits >= bits) {
1774			found_bits = extent_bits;
1775			break;
1776		} else if (extent_bits > max_bits) {
1777			max_bits = extent_bits;
1778		}
1779		i = next_zero;
1780	}
1781
1782	if (found_bits) {
1783		*offset = (u64)(i * ctl->unit) + bitmap_info->offset;
1784		*bytes = (u64)(found_bits) * ctl->unit;
1785		return 0;
1786	}
1787
1788	*bytes = (u64)(max_bits) * ctl->unit;
1789	bitmap_info->max_extent_size = *bytes;
1790	return -1;
1791}
1792
1793static inline u64 get_max_extent_size(struct btrfs_free_space *entry)
1794{
1795	if (entry->bitmap)
1796		return entry->max_extent_size;
1797	return entry->bytes;
1798}
1799
1800/* Cache the size of the max extent in bytes */
1801static struct btrfs_free_space *
1802find_free_space(struct btrfs_free_space_ctl *ctl, u64 *offset, u64 *bytes,
1803		unsigned long align, u64 *max_extent_size)
1804{
1805	struct btrfs_free_space *entry;
1806	struct rb_node *node;
1807	u64 tmp;
1808	u64 align_off;
1809	int ret;
1810
1811	if (!ctl->free_space_offset.rb_node)
1812		goto out;
1813
1814	entry = tree_search_offset(ctl, offset_to_bitmap(ctl, *offset), 0, 1);
1815	if (!entry)
1816		goto out;
1817
1818	for (node = &entry->offset_index; node; node = rb_next(node)) {
1819		entry = rb_entry(node, struct btrfs_free_space, offset_index);
1820		if (entry->bytes < *bytes) {
1821			*max_extent_size = max(get_max_extent_size(entry),
1822					       *max_extent_size);
1823			continue;
1824		}
1825
1826		/* make sure the space returned is big enough
1827		 * to match our requested alignment
1828		 */
1829		if (*bytes >= align) {
1830			tmp = entry->offset - ctl->start + align - 1;
1831			tmp = div64_u64(tmp, align);
1832			tmp = tmp * align + ctl->start;
1833			align_off = tmp - entry->offset;
1834		} else {
1835			align_off = 0;
1836			tmp = entry->offset;
1837		}
1838
1839		if (entry->bytes < *bytes + align_off) {
1840			*max_extent_size = max(get_max_extent_size(entry),
1841					       *max_extent_size);
1842			continue;
1843		}
1844
1845		if (entry->bitmap) {
1846			u64 size = *bytes;
1847
1848			ret = search_bitmap(ctl, entry, &tmp, &size, true);
1849			if (!ret) {
1850				*offset = tmp;
1851				*bytes = size;
1852				return entry;
1853			} else {
1854				*max_extent_size =
1855					max(get_max_extent_size(entry),
1856					    *max_extent_size);
1857			}
1858			continue;
1859		}
1860
1861		*offset = tmp;
1862		*bytes = entry->bytes - align_off;
1863		return entry;
1864	}
1865out:
1866	return NULL;
1867}
1868
1869static void add_new_bitmap(struct btrfs_free_space_ctl *ctl,
1870			   struct btrfs_free_space *info, u64 offset)
1871{
1872	info->offset = offset_to_bitmap(ctl, offset);
1873	info->bytes = 0;
1874	INIT_LIST_HEAD(&info->list);
1875	link_free_space(ctl, info);
1876	ctl->total_bitmaps++;
1877
1878	ctl->op->recalc_thresholds(ctl);
1879}
1880
1881static void free_bitmap(struct btrfs_free_space_ctl *ctl,
1882			struct btrfs_free_space *bitmap_info)
1883{
1884	unlink_free_space(ctl, bitmap_info);
1885	kmem_cache_free(btrfs_free_space_bitmap_cachep, bitmap_info->bitmap);
1886	kmem_cache_free(btrfs_free_space_cachep, bitmap_info);
1887	ctl->total_bitmaps--;
1888	ctl->op->recalc_thresholds(ctl);
1889}
1890
1891static noinline int remove_from_bitmap(struct btrfs_free_space_ctl *ctl,
1892			      struct btrfs_free_space *bitmap_info,
1893			      u64 *offset, u64 *bytes)
1894{
1895	u64 end;
1896	u64 search_start, search_bytes;
1897	int ret;
1898
1899again:
1900	end = bitmap_info->offset + (u64)(BITS_PER_BITMAP * ctl->unit) - 1;
1901
1902	/*
1903	 * We need to search for bits in this bitmap.  We could only cover some
1904	 * of the extent in this bitmap thanks to how we add space, so we need
1905	 * to search for as much as it as we can and clear that amount, and then
1906	 * go searching for the next bit.
1907	 */
1908	search_start = *offset;
1909	search_bytes = ctl->unit;
1910	search_bytes = min(search_bytes, end - search_start + 1);
1911	ret = search_bitmap(ctl, bitmap_info, &search_start, &search_bytes,
1912			    false);
1913	if (ret < 0 || search_start != *offset)
1914		return -EINVAL;
1915
1916	/* We may have found more bits than what we need */
1917	search_bytes = min(search_bytes, *bytes);
1918
1919	/* Cannot clear past the end of the bitmap */
1920	search_bytes = min(search_bytes, end - search_start + 1);
1921
1922	bitmap_clear_bits(ctl, bitmap_info, search_start, search_bytes);
1923	*offset += search_bytes;
1924	*bytes -= search_bytes;
1925
1926	if (*bytes) {
1927		struct rb_node *next = rb_next(&bitmap_info->offset_index);
1928		if (!bitmap_info->bytes)
1929			free_bitmap(ctl, bitmap_info);
1930
1931		/*
1932		 * no entry after this bitmap, but we still have bytes to
1933		 * remove, so something has gone wrong.
1934		 */
1935		if (!next)
1936			return -EINVAL;
1937
1938		bitmap_info = rb_entry(next, struct btrfs_free_space,
1939				       offset_index);
1940
1941		/*
1942		 * if the next entry isn't a bitmap we need to return to let the
1943		 * extent stuff do its work.
1944		 */
1945		if (!bitmap_info->bitmap)
1946			return -EAGAIN;
1947
1948		/*
1949		 * Ok the next item is a bitmap, but it may not actually hold
1950		 * the information for the rest of this free space stuff, so
1951		 * look for it, and if we don't find it return so we can try
1952		 * everything over again.
1953		 */
1954		search_start = *offset;
1955		search_bytes = ctl->unit;
1956		ret = search_bitmap(ctl, bitmap_info, &search_start,
1957				    &search_bytes, false);
1958		if (ret < 0 || search_start != *offset)
1959			return -EAGAIN;
1960
1961		goto again;
1962	} else if (!bitmap_info->bytes)
1963		free_bitmap(ctl, bitmap_info);
1964
1965	return 0;
1966}
1967
1968static u64 add_bytes_to_bitmap(struct btrfs_free_space_ctl *ctl,
1969			       struct btrfs_free_space *info, u64 offset,
1970			       u64 bytes)
1971{
1972	u64 bytes_to_set = 0;
1973	u64 end;
1974
1975	end = info->offset + (u64)(BITS_PER_BITMAP * ctl->unit);
1976
1977	bytes_to_set = min(end - offset, bytes);
1978
1979	bitmap_set_bits(ctl, info, offset, bytes_to_set);
1980
1981	/*
1982	 * We set some bytes, we have no idea what the max extent size is
1983	 * anymore.
1984	 */
1985	info->max_extent_size = 0;
1986
1987	return bytes_to_set;
1988
1989}
1990
1991static bool use_bitmap(struct btrfs_free_space_ctl *ctl,
1992		      struct btrfs_free_space *info)
1993{
1994	struct btrfs_block_group_cache *block_group = ctl->private;
1995	struct btrfs_fs_info *fs_info = block_group->fs_info;
1996	bool forced = false;
1997
1998#ifdef CONFIG_BTRFS_DEBUG
1999	if (btrfs_should_fragment_free_space(block_group))
2000		forced = true;
2001#endif
2002
2003	/*
2004	 * If we are below the extents threshold then we can add this as an
2005	 * extent, and don't have to deal with the bitmap
2006	 */
2007	if (!forced && ctl->free_extents < ctl->extents_thresh) {
2008		/*
2009		 * If this block group has some small extents we don't want to
2010		 * use up all of our free slots in the cache with them, we want
2011		 * to reserve them to larger extents, however if we have plenty
2012		 * of cache left then go ahead an dadd them, no sense in adding
2013		 * the overhead of a bitmap if we don't have to.
2014		 */
2015		if (info->bytes <= fs_info->sectorsize * 4) {
2016			if (ctl->free_extents * 2 <= ctl->extents_thresh)
2017				return false;
2018		} else {
2019			return false;
2020		}
2021	}
2022
2023	/*
2024	 * The original block groups from mkfs can be really small, like 8
2025	 * megabytes, so don't bother with a bitmap for those entries.  However
2026	 * some block groups can be smaller than what a bitmap would cover but
2027	 * are still large enough that they could overflow the 32k memory limit,
2028	 * so allow those block groups to still be allowed to have a bitmap
2029	 * entry.
2030	 */
2031	if (((BITS_PER_BITMAP * ctl->unit) >> 1) > block_group->key.offset)
2032		return false;
2033
2034	return true;
2035}
2036
2037static const struct btrfs_free_space_op free_space_op = {
2038	.recalc_thresholds	= recalculate_thresholds,
2039	.use_bitmap		= use_bitmap,
2040};
2041
2042static int insert_into_bitmap(struct btrfs_free_space_ctl *ctl,
2043			      struct btrfs_free_space *info)
2044{
2045	struct btrfs_free_space *bitmap_info;
2046	struct btrfs_block_group_cache *block_group = NULL;
2047	int added = 0;
2048	u64 bytes, offset, bytes_added;
2049	int ret;
2050
2051	bytes = info->bytes;
2052	offset = info->offset;
2053
2054	if (!ctl->op->use_bitmap(ctl, info))
2055		return 0;
2056
2057	if (ctl->op == &free_space_op)
2058		block_group = ctl->private;
2059again:
2060	/*
2061	 * Since we link bitmaps right into the cluster we need to see if we
2062	 * have a cluster here, and if so and it has our bitmap we need to add
2063	 * the free space to that bitmap.
2064	 */
2065	if (block_group && !list_empty(&block_group->cluster_list)) {
2066		struct btrfs_free_cluster *cluster;
2067		struct rb_node *node;
2068		struct btrfs_free_space *entry;
2069
2070		cluster = list_entry(block_group->cluster_list.next,
2071				     struct btrfs_free_cluster,
2072				     block_group_list);
2073		spin_lock(&cluster->lock);
2074		node = rb_first(&cluster->root);
2075		if (!node) {
2076			spin_unlock(&cluster->lock);
2077			goto no_cluster_bitmap;
2078		}
2079
2080		entry = rb_entry(node, struct btrfs_free_space, offset_index);
2081		if (!entry->bitmap) {
2082			spin_unlock(&cluster->lock);
2083			goto no_cluster_bitmap;
2084		}
2085
2086		if (entry->offset == offset_to_bitmap(ctl, offset)) {
2087			bytes_added = add_bytes_to_bitmap(ctl, entry,
2088							  offset, bytes);
2089			bytes -= bytes_added;
2090			offset += bytes_added;
2091		}
2092		spin_unlock(&cluster->lock);
2093		if (!bytes) {
2094			ret = 1;
2095			goto out;
2096		}
2097	}
2098
2099no_cluster_bitmap:
2100	bitmap_info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
2101					 1, 0);
2102	if (!bitmap_info) {
2103		ASSERT(added == 0);
2104		goto new_bitmap;
2105	}
2106
2107	bytes_added = add_bytes_to_bitmap(ctl, bitmap_info, offset, bytes);
2108	bytes -= bytes_added;
2109	offset += bytes_added;
2110	added = 0;
2111
2112	if (!bytes) {
2113		ret = 1;
2114		goto out;
2115	} else
2116		goto again;
2117
2118new_bitmap:
2119	if (info && info->bitmap) {
2120		add_new_bitmap(ctl, info, offset);
2121		added = 1;
2122		info = NULL;
2123		goto again;
2124	} else {
2125		spin_unlock(&ctl->tree_lock);
2126
2127		/* no pre-allocated info, allocate a new one */
2128		if (!info) {
2129			info = kmem_cache_zalloc(btrfs_free_space_cachep,
2130						 GFP_NOFS);
2131			if (!info) {
2132				spin_lock(&ctl->tree_lock);
2133				ret = -ENOMEM;
2134				goto out;
2135			}
2136		}
2137
2138		/* allocate the bitmap */
2139		info->bitmap = kmem_cache_zalloc(btrfs_free_space_bitmap_cachep,
2140						 GFP_NOFS);
2141		spin_lock(&ctl->tree_lock);
2142		if (!info->bitmap) {
2143			ret = -ENOMEM;
2144			goto out;
2145		}
2146		goto again;
2147	}
2148
2149out:
2150	if (info) {
2151		if (info->bitmap)
2152			kmem_cache_free(btrfs_free_space_bitmap_cachep,
2153					info->bitmap);
2154		kmem_cache_free(btrfs_free_space_cachep, info);
2155	}
2156
2157	return ret;
2158}
2159
2160static bool try_merge_free_space(struct btrfs_free_space_ctl *ctl,
2161			  struct btrfs_free_space *info, bool update_stat)
2162{
2163	struct btrfs_free_space *left_info;
2164	struct btrfs_free_space *right_info;
2165	bool merged = false;
2166	u64 offset = info->offset;
2167	u64 bytes = info->bytes;
2168
2169	/*
2170	 * first we want to see if there is free space adjacent to the range we
2171	 * are adding, if there is remove that struct and add a new one to
2172	 * cover the entire range
2173	 */
2174	right_info = tree_search_offset(ctl, offset + bytes, 0, 0);
2175	if (right_info && rb_prev(&right_info->offset_index))
2176		left_info = rb_entry(rb_prev(&right_info->offset_index),
2177				     struct btrfs_free_space, offset_index);
2178	else
2179		left_info = tree_search_offset(ctl, offset - 1, 0, 0);
2180
2181	if (right_info && !right_info->bitmap) {
2182		if (update_stat)
2183			unlink_free_space(ctl, right_info);
2184		else
2185			__unlink_free_space(ctl, right_info);
2186		info->bytes += right_info->bytes;
2187		kmem_cache_free(btrfs_free_space_cachep, right_info);
2188		merged = true;
2189	}
2190
2191	if (left_info && !left_info->bitmap &&
2192	    left_info->offset + left_info->bytes == offset) {
2193		if (update_stat)
2194			unlink_free_space(ctl, left_info);
2195		else
2196			__unlink_free_space(ctl, left_info);
2197		info->offset = left_info->offset;
2198		info->bytes += left_info->bytes;
2199		kmem_cache_free(btrfs_free_space_cachep, left_info);
2200		merged = true;
2201	}
2202
2203	return merged;
2204}
2205
2206static bool steal_from_bitmap_to_end(struct btrfs_free_space_ctl *ctl,
2207				     struct btrfs_free_space *info,
2208				     bool update_stat)
2209{
2210	struct btrfs_free_space *bitmap;
2211	unsigned long i;
2212	unsigned long j;
2213	const u64 end = info->offset + info->bytes;
2214	const u64 bitmap_offset = offset_to_bitmap(ctl, end);
2215	u64 bytes;
2216
2217	bitmap = tree_search_offset(ctl, bitmap_offset, 1, 0);
2218	if (!bitmap)
2219		return false;
2220
2221	i = offset_to_bit(bitmap->offset, ctl->unit, end);
2222	j = find_next_zero_bit(bitmap->bitmap, BITS_PER_BITMAP, i);
2223	if (j == i)
2224		return false;
2225	bytes = (j - i) * ctl->unit;
2226	info->bytes += bytes;
2227
2228	if (update_stat)
2229		bitmap_clear_bits(ctl, bitmap, end, bytes);
2230	else
2231		__bitmap_clear_bits(ctl, bitmap, end, bytes);
2232
2233	if (!bitmap->bytes)
2234		free_bitmap(ctl, bitmap);
2235
2236	return true;
2237}
2238
2239static bool steal_from_bitmap_to_front(struct btrfs_free_space_ctl *ctl,
2240				       struct btrfs_free_space *info,
2241				       bool update_stat)
2242{
2243	struct btrfs_free_space *bitmap;
2244	u64 bitmap_offset;
2245	unsigned long i;
2246	unsigned long j;
2247	unsigned long prev_j;
2248	u64 bytes;
2249
2250	bitmap_offset = offset_to_bitmap(ctl, info->offset);
2251	/* If we're on a boundary, try the previous logical bitmap. */
2252	if (bitmap_offset == info->offset) {
2253		if (info->offset == 0)
2254			return false;
2255		bitmap_offset = offset_to_bitmap(ctl, info->offset - 1);
2256	}
2257
2258	bitmap = tree_search_offset(ctl, bitmap_offset, 1, 0);
2259	if (!bitmap)
2260		return false;
2261
2262	i = offset_to_bit(bitmap->offset, ctl->unit, info->offset) - 1;
2263	j = 0;
2264	prev_j = (unsigned long)-1;
2265	for_each_clear_bit_from(j, bitmap->bitmap, BITS_PER_BITMAP) {
2266		if (j > i)
2267			break;
2268		prev_j = j;
2269	}
2270	if (prev_j == i)
2271		return false;
2272
2273	if (prev_j == (unsigned long)-1)
2274		bytes = (i + 1) * ctl->unit;
2275	else
2276		bytes = (i - prev_j) * ctl->unit;
2277
2278	info->offset -= bytes;
2279	info->bytes += bytes;
2280
2281	if (update_stat)
2282		bitmap_clear_bits(ctl, bitmap, info->offset, bytes);
2283	else
2284		__bitmap_clear_bits(ctl, bitmap, info->offset, bytes);
2285
2286	if (!bitmap->bytes)
2287		free_bitmap(ctl, bitmap);
2288
2289	return true;
2290}
2291
2292/*
2293 * We prefer always to allocate from extent entries, both for clustered and
2294 * non-clustered allocation requests. So when attempting to add a new extent
2295 * entry, try to see if there's adjacent free space in bitmap entries, and if
2296 * there is, migrate that space from the bitmaps to the extent.
2297 * Like this we get better chances of satisfying space allocation requests
2298 * because we attempt to satisfy them based on a single cache entry, and never
2299 * on 2 or more entries - even if the entries represent a contiguous free space
2300 * region (e.g. 1 extent entry + 1 bitmap entry starting where the extent entry
2301 * ends).
2302 */
2303static void steal_from_bitmap(struct btrfs_free_space_ctl *ctl,
2304			      struct btrfs_free_space *info,
2305			      bool update_stat)
2306{
2307	/*
2308	 * Only work with disconnected entries, as we can change their offset,
2309	 * and must be extent entries.
2310	 */
2311	ASSERT(!info->bitmap);
2312	ASSERT(RB_EMPTY_NODE(&info->offset_index));
2313
2314	if (ctl->total_bitmaps > 0) {
2315		bool stole_end;
2316		bool stole_front = false;
2317
2318		stole_end = steal_from_bitmap_to_end(ctl, info, update_stat);
2319		if (ctl->total_bitmaps > 0)
2320			stole_front = steal_from_bitmap_to_front(ctl, info,
2321								 update_stat);
2322
2323		if (stole_end || stole_front)
2324			try_merge_free_space(ctl, info, update_stat);
2325	}
2326}
2327
2328int __btrfs_add_free_space(struct btrfs_fs_info *fs_info,
2329			   struct btrfs_free_space_ctl *ctl,
2330			   u64 offset, u64 bytes)
2331{
2332	struct btrfs_free_space *info;
2333	int ret = 0;
2334
2335	info = kmem_cache_zalloc(btrfs_free_space_cachep, GFP_NOFS);
2336	if (!info)
2337		return -ENOMEM;
2338
2339	info->offset = offset;
2340	info->bytes = bytes;
2341	RB_CLEAR_NODE(&info->offset_index);
2342
2343	spin_lock(&ctl->tree_lock);
2344
2345	if (try_merge_free_space(ctl, info, true))
2346		goto link;
2347
2348	/*
2349	 * There was no extent directly to the left or right of this new
2350	 * extent then we know we're going to have to allocate a new extent, so
2351	 * before we do that see if we need to drop this into a bitmap
2352	 */
2353	ret = insert_into_bitmap(ctl, info);
2354	if (ret < 0) {
2355		goto out;
2356	} else if (ret) {
2357		ret = 0;
2358		goto out;
2359	}
2360link:
2361	/*
2362	 * Only steal free space from adjacent bitmaps if we're sure we're not
2363	 * going to add the new free space to existing bitmap entries - because
2364	 * that would mean unnecessary work that would be reverted. Therefore
2365	 * attempt to steal space from bitmaps if we're adding an extent entry.
2366	 */
2367	steal_from_bitmap(ctl, info, true);
2368
2369	ret = link_free_space(ctl, info);
2370	if (ret)
2371		kmem_cache_free(btrfs_free_space_cachep, info);
2372out:
2373	spin_unlock(&ctl->tree_lock);
2374
2375	if (ret) {
2376		btrfs_crit(fs_info, "unable to add free space :%d", ret);
2377		ASSERT(ret != -EEXIST);
2378	}
2379
2380	return ret;
2381}
2382
2383int btrfs_add_free_space(struct btrfs_block_group_cache *block_group,
2384			 u64 bytenr, u64 size)
2385{
2386	return __btrfs_add_free_space(block_group->fs_info,
2387				      block_group->free_space_ctl,
2388				      bytenr, size);
2389}
2390
2391int btrfs_remove_free_space(struct btrfs_block_group_cache *block_group,
2392			    u64 offset, u64 bytes)
2393{
2394	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2395	struct btrfs_free_space *info;
2396	int ret;
2397	bool re_search = false;
2398
2399	spin_lock(&ctl->tree_lock);
2400
2401again:
2402	ret = 0;
2403	if (!bytes)
2404		goto out_lock;
2405
2406	info = tree_search_offset(ctl, offset, 0, 0);
2407	if (!info) {
2408		/*
2409		 * oops didn't find an extent that matched the space we wanted
2410		 * to remove, look for a bitmap instead
2411		 */
2412		info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
2413					  1, 0);
2414		if (!info) {
2415			/*
2416			 * If we found a partial bit of our free space in a
2417			 * bitmap but then couldn't find the other part this may
2418			 * be a problem, so WARN about it.
2419			 */
2420			WARN_ON(re_search);
2421			goto out_lock;
2422		}
2423	}
2424
2425	re_search = false;
2426	if (!info->bitmap) {
2427		unlink_free_space(ctl, info);
2428		if (offset == info->offset) {
2429			u64 to_free = min(bytes, info->bytes);
2430
2431			info->bytes -= to_free;
2432			info->offset += to_free;
2433			if (info->bytes) {
2434				ret = link_free_space(ctl, info);
2435				WARN_ON(ret);
2436			} else {
2437				kmem_cache_free(btrfs_free_space_cachep, info);
2438			}
2439
2440			offset += to_free;
2441			bytes -= to_free;
2442			goto again;
2443		} else {
2444			u64 old_end = info->bytes + info->offset;
2445
2446			info->bytes = offset - info->offset;
2447			ret = link_free_space(ctl, info);
2448			WARN_ON(ret);
2449			if (ret)
2450				goto out_lock;
2451
2452			/* Not enough bytes in this entry to satisfy us */
2453			if (old_end < offset + bytes) {
2454				bytes -= old_end - offset;
2455				offset = old_end;
2456				goto again;
2457			} else if (old_end == offset + bytes) {
2458				/* all done */
2459				goto out_lock;
2460			}
2461			spin_unlock(&ctl->tree_lock);
2462
2463			ret = btrfs_add_free_space(block_group, offset + bytes,
2464						   old_end - (offset + bytes));
2465			WARN_ON(ret);
2466			goto out;
2467		}
2468	}
2469
2470	ret = remove_from_bitmap(ctl, info, &offset, &bytes);
2471	if (ret == -EAGAIN) {
2472		re_search = true;
2473		goto again;
2474	}
2475out_lock:
2476	spin_unlock(&ctl->tree_lock);
2477out:
2478	return ret;
2479}
2480
2481void btrfs_dump_free_space(struct btrfs_block_group_cache *block_group,
2482			   u64 bytes)
2483{
2484	struct btrfs_fs_info *fs_info = block_group->fs_info;
2485	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2486	struct btrfs_free_space *info;
2487	struct rb_node *n;
2488	int count = 0;
2489
2490	spin_lock(&ctl->tree_lock);
2491	for (n = rb_first(&ctl->free_space_offset); n; n = rb_next(n)) {
2492		info = rb_entry(n, struct btrfs_free_space, offset_index);
2493		if (info->bytes >= bytes && !block_group->ro)
2494			count++;
2495		btrfs_crit(fs_info, "entry offset %llu, bytes %llu, bitmap %s",
2496			   info->offset, info->bytes,
2497		       (info->bitmap) ? "yes" : "no");
2498	}
2499	spin_unlock(&ctl->tree_lock);
2500	btrfs_info(fs_info, "block group has cluster?: %s",
2501	       list_empty(&block_group->cluster_list) ? "no" : "yes");
2502	btrfs_info(fs_info,
2503		   "%d blocks of free space at or bigger than bytes is", count);
2504}
2505
2506void btrfs_init_free_space_ctl(struct btrfs_block_group_cache *block_group)
2507{
2508	struct btrfs_fs_info *fs_info = block_group->fs_info;
2509	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2510
2511	spin_lock_init(&ctl->tree_lock);
2512	ctl->unit = fs_info->sectorsize;
2513	ctl->start = block_group->key.objectid;
2514	ctl->private = block_group;
2515	ctl->op = &free_space_op;
2516	INIT_LIST_HEAD(&ctl->trimming_ranges);
2517	mutex_init(&ctl->cache_writeout_mutex);
2518
2519	/*
2520	 * we only want to have 32k of ram per block group for keeping
2521	 * track of free space, and if we pass 1/2 of that we want to
2522	 * start converting things over to using bitmaps
2523	 */
2524	ctl->extents_thresh = (SZ_32K / 2) / sizeof(struct btrfs_free_space);
2525}
2526
2527/*
2528 * for a given cluster, put all of its extents back into the free
2529 * space cache.  If the block group passed doesn't match the block group
2530 * pointed to by the cluster, someone else raced in and freed the
2531 * cluster already.  In that case, we just return without changing anything
2532 */
2533static int
2534__btrfs_return_cluster_to_free_space(
2535			     struct btrfs_block_group_cache *block_group,
2536			     struct btrfs_free_cluster *cluster)
2537{
2538	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2539	struct btrfs_free_space *entry;
2540	struct rb_node *node;
2541
2542	spin_lock(&cluster->lock);
2543	if (cluster->block_group != block_group)
2544		goto out;
2545
2546	cluster->block_group = NULL;
2547	cluster->window_start = 0;
2548	list_del_init(&cluster->block_group_list);
2549
2550	node = rb_first(&cluster->root);
2551	while (node) {
2552		bool bitmap;
2553
2554		entry = rb_entry(node, struct btrfs_free_space, offset_index);
2555		node = rb_next(&entry->offset_index);
2556		rb_erase(&entry->offset_index, &cluster->root);
2557		RB_CLEAR_NODE(&entry->offset_index);
2558
2559		bitmap = (entry->bitmap != NULL);
2560		if (!bitmap) {
2561			try_merge_free_space(ctl, entry, false);
2562			steal_from_bitmap(ctl, entry, false);
2563		}
2564		tree_insert_offset(&ctl->free_space_offset,
2565				   entry->offset, &entry->offset_index, bitmap);
2566	}
2567	cluster->root = RB_ROOT;
2568
2569out:
2570	spin_unlock(&cluster->lock);
2571	btrfs_put_block_group(block_group);
2572	return 0;
2573}
2574
2575static void __btrfs_remove_free_space_cache_locked(
2576				struct btrfs_free_space_ctl *ctl)
2577{
2578	struct btrfs_free_space *info;
2579	struct rb_node *node;
2580
2581	while ((node = rb_last(&ctl->free_space_offset)) != NULL) {
2582		info = rb_entry(node, struct btrfs_free_space, offset_index);
2583		if (!info->bitmap) {
2584			unlink_free_space(ctl, info);
2585			kmem_cache_free(btrfs_free_space_cachep, info);
2586		} else {
2587			free_bitmap(ctl, info);
2588		}
2589
2590		cond_resched_lock(&ctl->tree_lock);
2591	}
2592}
2593
2594void __btrfs_remove_free_space_cache(struct btrfs_free_space_ctl *ctl)
2595{
2596	spin_lock(&ctl->tree_lock);
2597	__btrfs_remove_free_space_cache_locked(ctl);
2598	spin_unlock(&ctl->tree_lock);
2599}
2600
2601void btrfs_remove_free_space_cache(struct btrfs_block_group_cache *block_group)
2602{
2603	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2604	struct btrfs_free_cluster *cluster;
2605	struct list_head *head;
2606
2607	spin_lock(&ctl->tree_lock);
2608	while ((head = block_group->cluster_list.next) !=
2609	       &block_group->cluster_list) {
2610		cluster = list_entry(head, struct btrfs_free_cluster,
2611				     block_group_list);
2612
2613		WARN_ON(cluster->block_group != block_group);
2614		__btrfs_return_cluster_to_free_space(block_group, cluster);
2615
2616		cond_resched_lock(&ctl->tree_lock);
2617	}
2618	__btrfs_remove_free_space_cache_locked(ctl);
2619	spin_unlock(&ctl->tree_lock);
2620
2621}
2622
2623u64 btrfs_find_space_for_alloc(struct btrfs_block_group_cache *block_group,
2624			       u64 offset, u64 bytes, u64 empty_size,
2625			       u64 *max_extent_size)
2626{
2627	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2628	struct btrfs_free_space *entry = NULL;
2629	u64 bytes_search = bytes + empty_size;
2630	u64 ret = 0;
2631	u64 align_gap = 0;
2632	u64 align_gap_len = 0;
2633
2634	spin_lock(&ctl->tree_lock);
2635	entry = find_free_space(ctl, &offset, &bytes_search,
2636				block_group->full_stripe_len, max_extent_size);
2637	if (!entry)
2638		goto out;
2639
2640	ret = offset;
2641	if (entry->bitmap) {
2642		bitmap_clear_bits(ctl, entry, offset, bytes);
2643		if (!entry->bytes)
2644			free_bitmap(ctl, entry);
2645	} else {
2646		unlink_free_space(ctl, entry);
2647		align_gap_len = offset - entry->offset;
2648		align_gap = entry->offset;
2649
2650		entry->offset = offset + bytes;
2651		WARN_ON(entry->bytes < bytes + align_gap_len);
2652
2653		entry->bytes -= bytes + align_gap_len;
2654		if (!entry->bytes)
2655			kmem_cache_free(btrfs_free_space_cachep, entry);
2656		else
2657			link_free_space(ctl, entry);
2658	}
2659out:
2660	spin_unlock(&ctl->tree_lock);
2661
2662	if (align_gap_len)
2663		__btrfs_add_free_space(block_group->fs_info, ctl,
2664				       align_gap, align_gap_len);
2665	return ret;
2666}
2667
2668/*
2669 * given a cluster, put all of its extents back into the free space
2670 * cache.  If a block group is passed, this function will only free
2671 * a cluster that belongs to the passed block group.
2672 *
2673 * Otherwise, it'll get a reference on the block group pointed to by the
2674 * cluster and remove the cluster from it.
2675 */
2676int btrfs_return_cluster_to_free_space(
2677			       struct btrfs_block_group_cache *block_group,
2678			       struct btrfs_free_cluster *cluster)
2679{
2680	struct btrfs_free_space_ctl *ctl;
2681	int ret;
2682
2683	/* first, get a safe pointer to the block group */
2684	spin_lock(&cluster->lock);
2685	if (!block_group) {
2686		block_group = cluster->block_group;
2687		if (!block_group) {
2688			spin_unlock(&cluster->lock);
2689			return 0;
2690		}
2691	} else if (cluster->block_group != block_group) {
2692		/* someone else has already freed it don't redo their work */
2693		spin_unlock(&cluster->lock);
2694		return 0;
2695	}
2696	atomic_inc(&block_group->count);
2697	spin_unlock(&cluster->lock);
2698
2699	ctl = block_group->free_space_ctl;
2700
2701	/* now return any extents the cluster had on it */
2702	spin_lock(&ctl->tree_lock);
2703	ret = __btrfs_return_cluster_to_free_space(block_group, cluster);
2704	spin_unlock(&ctl->tree_lock);
2705
2706	/* finally drop our ref */
2707	btrfs_put_block_group(block_group);
2708	return ret;
2709}
2710
2711static u64 btrfs_alloc_from_bitmap(struct btrfs_block_group_cache *block_group,
2712				   struct btrfs_free_cluster *cluster,
2713				   struct btrfs_free_space *entry,
2714				   u64 bytes, u64 min_start,
2715				   u64 *max_extent_size)
2716{
2717	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2718	int err;
2719	u64 search_start = cluster->window_start;
2720	u64 search_bytes = bytes;
2721	u64 ret = 0;
2722
2723	search_start = min_start;
2724	search_bytes = bytes;
2725
2726	err = search_bitmap(ctl, entry, &search_start, &search_bytes, true);
2727	if (err) {
2728		*max_extent_size = max(get_max_extent_size(entry),
2729				       *max_extent_size);
2730		return 0;
2731	}
2732
2733	ret = search_start;
2734	__bitmap_clear_bits(ctl, entry, ret, bytes);
2735
2736	return ret;
2737}
2738
2739/*
2740 * given a cluster, try to allocate 'bytes' from it, returns 0
2741 * if it couldn't find anything suitably large, or a logical disk offset
2742 * if things worked out
2743 */
2744u64 btrfs_alloc_from_cluster(struct btrfs_block_group_cache *block_group,
2745			     struct btrfs_free_cluster *cluster, u64 bytes,
2746			     u64 min_start, u64 *max_extent_size)
2747{
2748	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2749	struct btrfs_free_space *entry = NULL;
2750	struct rb_node *node;
2751	u64 ret = 0;
2752
2753	spin_lock(&cluster->lock);
2754	if (bytes > cluster->max_size)
2755		goto out;
2756
2757	if (cluster->block_group != block_group)
2758		goto out;
2759
2760	node = rb_first(&cluster->root);
2761	if (!node)
2762		goto out;
2763
2764	entry = rb_entry(node, struct btrfs_free_space, offset_index);
2765	while (1) {
2766		if (entry->bytes < bytes)
2767			*max_extent_size = max(get_max_extent_size(entry),
2768					       *max_extent_size);
2769
2770		if (entry->bytes < bytes ||
2771		    (!entry->bitmap && entry->offset < min_start)) {
2772			node = rb_next(&entry->offset_index);
2773			if (!node)
2774				break;
2775			entry = rb_entry(node, struct btrfs_free_space,
2776					 offset_index);
2777			continue;
2778		}
2779
2780		if (entry->bitmap) {
2781			ret = btrfs_alloc_from_bitmap(block_group,
2782						      cluster, entry, bytes,
2783						      cluster->window_start,
2784						      max_extent_size);
2785			if (ret == 0) {
2786				node = rb_next(&entry->offset_index);
2787				if (!node)
2788					break;
2789				entry = rb_entry(node, struct btrfs_free_space,
2790						 offset_index);
2791				continue;
2792			}
2793			cluster->window_start += bytes;
2794		} else {
2795			ret = entry->offset;
2796
2797			entry->offset += bytes;
2798			entry->bytes -= bytes;
2799		}
2800
2801		if (entry->bytes == 0)
2802			rb_erase(&entry->offset_index, &cluster->root);
2803		break;
2804	}
2805out:
2806	spin_unlock(&cluster->lock);
2807
2808	if (!ret)
2809		return 0;
2810
2811	spin_lock(&ctl->tree_lock);
2812
2813	ctl->free_space -= bytes;
2814	if (entry->bytes == 0) {
2815		ctl->free_extents--;
2816		if (entry->bitmap) {
2817			kmem_cache_free(btrfs_free_space_bitmap_cachep,
2818					entry->bitmap);
2819			ctl->total_bitmaps--;
2820			ctl->op->recalc_thresholds(ctl);
2821		}
2822		kmem_cache_free(btrfs_free_space_cachep, entry);
2823	}
2824
2825	spin_unlock(&ctl->tree_lock);
2826
2827	return ret;
2828}
2829
2830static int btrfs_bitmap_cluster(struct btrfs_block_group_cache *block_group,
2831				struct btrfs_free_space *entry,
2832				struct btrfs_free_cluster *cluster,
2833				u64 offset, u64 bytes,
2834				u64 cont1_bytes, u64 min_bytes)
2835{
2836	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2837	unsigned long next_zero;
2838	unsigned long i;
2839	unsigned long want_bits;
2840	unsigned long min_bits;
2841	unsigned long found_bits;
2842	unsigned long max_bits = 0;
2843	unsigned long start = 0;
2844	unsigned long total_found = 0;
2845	int ret;
2846
2847	i = offset_to_bit(entry->offset, ctl->unit,
2848			  max_t(u64, offset, entry->offset));
2849	want_bits = bytes_to_bits(bytes, ctl->unit);
2850	min_bits = bytes_to_bits(min_bytes, ctl->unit);
2851
2852	/*
2853	 * Don't bother looking for a cluster in this bitmap if it's heavily
2854	 * fragmented.
2855	 */
2856	if (entry->max_extent_size &&
2857	    entry->max_extent_size < cont1_bytes)
2858		return -ENOSPC;
2859again:
2860	found_bits = 0;
2861	for_each_set_bit_from(i, entry->bitmap, BITS_PER_BITMAP) {
2862		next_zero = find_next_zero_bit(entry->bitmap,
2863					       BITS_PER_BITMAP, i);
2864		if (next_zero - i >= min_bits) {
2865			found_bits = next_zero - i;
2866			if (found_bits > max_bits)
2867				max_bits = found_bits;
2868			break;
2869		}
2870		if (next_zero - i > max_bits)
2871			max_bits = next_zero - i;
2872		i = next_zero;
2873	}
2874
2875	if (!found_bits) {
2876		entry->max_extent_size = (u64)max_bits * ctl->unit;
2877		return -ENOSPC;
2878	}
2879
2880	if (!total_found) {
2881		start = i;
2882		cluster->max_size = 0;
2883	}
2884
2885	total_found += found_bits;
2886
2887	if (cluster->max_size < found_bits * ctl->unit)
2888		cluster->max_size = found_bits * ctl->unit;
2889
2890	if (total_found < want_bits || cluster->max_size < cont1_bytes) {
2891		i = next_zero + 1;
2892		goto again;
2893	}
2894
2895	cluster->window_start = start * ctl->unit + entry->offset;
2896	rb_erase(&entry->offset_index, &ctl->free_space_offset);
2897	ret = tree_insert_offset(&cluster->root, entry->offset,
2898				 &entry->offset_index, 1);
2899	ASSERT(!ret); /* -EEXIST; Logic error */
2900
2901	trace_btrfs_setup_cluster(block_group, cluster,
2902				  total_found * ctl->unit, 1);
2903	return 0;
2904}
2905
2906/*
2907 * This searches the block group for just extents to fill the cluster with.
2908 * Try to find a cluster with at least bytes total bytes, at least one
2909 * extent of cont1_bytes, and other clusters of at least min_bytes.
2910 */
2911static noinline int
2912setup_cluster_no_bitmap(struct btrfs_block_group_cache *block_group,
2913			struct btrfs_free_cluster *cluster,
2914			struct list_head *bitmaps, u64 offset, u64 bytes,
2915			u64 cont1_bytes, u64 min_bytes)
2916{
2917	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2918	struct btrfs_free_space *first = NULL;
2919	struct btrfs_free_space *entry = NULL;
2920	struct btrfs_free_space *last;
2921	struct rb_node *node;
2922	u64 window_free;
2923	u64 max_extent;
2924	u64 total_size = 0;
2925
2926	entry = tree_search_offset(ctl, offset, 0, 1);
2927	if (!entry)
2928		return -ENOSPC;
2929
2930	/*
2931	 * We don't want bitmaps, so just move along until we find a normal
2932	 * extent entry.
2933	 */
2934	while (entry->bitmap || entry->bytes < min_bytes) {
2935		if (entry->bitmap && list_empty(&entry->list))
2936			list_add_tail(&entry->list, bitmaps);
2937		node = rb_next(&entry->offset_index);
2938		if (!node)
2939			return -ENOSPC;
2940		entry = rb_entry(node, struct btrfs_free_space, offset_index);
2941	}
2942
2943	window_free = entry->bytes;
2944	max_extent = entry->bytes;
2945	first = entry;
2946	last = entry;
2947
2948	for (node = rb_next(&entry->offset_index); node;
2949	     node = rb_next(&entry->offset_index)) {
2950		entry = rb_entry(node, struct btrfs_free_space, offset_index);
2951
2952		if (entry->bitmap) {
2953			if (list_empty(&entry->list))
2954				list_add_tail(&entry->list, bitmaps);
2955			continue;
2956		}
2957
2958		if (entry->bytes < min_bytes)
2959			continue;
2960
2961		last = entry;
2962		window_free += entry->bytes;
2963		if (entry->bytes > max_extent)
2964			max_extent = entry->bytes;
2965	}
2966
2967	if (window_free < bytes || max_extent < cont1_bytes)
2968		return -ENOSPC;
2969
2970	cluster->window_start = first->offset;
2971
2972	node = &first->offset_index;
2973
2974	/*
2975	 * now we've found our entries, pull them out of the free space
2976	 * cache and put them into the cluster rbtree
2977	 */
2978	do {
2979		int ret;
2980
2981		entry = rb_entry(node, struct btrfs_free_space, offset_index);
2982		node = rb_next(&entry->offset_index);
2983		if (entry->bitmap || entry->bytes < min_bytes)
2984			continue;
2985
2986		rb_erase(&entry->offset_index, &ctl->free_space_offset);
2987		ret = tree_insert_offset(&cluster->root, entry->offset,
2988					 &entry->offset_index, 0);
2989		total_size += entry->bytes;
2990		ASSERT(!ret); /* -EEXIST; Logic error */
2991	} while (node && entry != last);
2992
2993	cluster->max_size = max_extent;
2994	trace_btrfs_setup_cluster(block_group, cluster, total_size, 0);
2995	return 0;
2996}
2997
2998/*
2999 * This specifically looks for bitmaps that may work in the cluster, we assume
3000 * that we have already failed to find extents that will work.
3001 */
3002static noinline int
3003setup_cluster_bitmap(struct btrfs_block_group_cache *block_group,
3004		     struct btrfs_free_cluster *cluster,
3005		     struct list_head *bitmaps, u64 offset, u64 bytes,
3006		     u64 cont1_bytes, u64 min_bytes)
3007{
3008	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
3009	struct btrfs_free_space *entry = NULL;
3010	int ret = -ENOSPC;
3011	u64 bitmap_offset = offset_to_bitmap(ctl, offset);
3012
3013	if (ctl->total_bitmaps == 0)
3014		return -ENOSPC;
3015
3016	/*
3017	 * The bitmap that covers offset won't be in the list unless offset
3018	 * is just its start offset.
3019	 */
3020	if (!list_empty(bitmaps))
3021		entry = list_first_entry(bitmaps, struct btrfs_free_space, list);
3022
3023	if (!entry || entry->offset != bitmap_offset) {
3024		entry = tree_search_offset(ctl, bitmap_offset, 1, 0);
3025		if (entry && list_empty(&entry->list))
3026			list_add(&entry->list, bitmaps);
3027	}
3028
3029	list_for_each_entry(entry, bitmaps, list) {
3030		if (entry->bytes < bytes)
3031			continue;
3032		ret = btrfs_bitmap_cluster(block_group, entry, cluster, offset,
3033					   bytes, cont1_bytes, min_bytes);
3034		if (!ret)
3035			return 0;
3036	}
3037
3038	/*
3039	 * The bitmaps list has all the bitmaps that record free space
3040	 * starting after offset, so no more search is required.
3041	 */
3042	return -ENOSPC;
3043}
3044
3045/*
3046 * here we try to find a cluster of blocks in a block group.  The goal
3047 * is to find at least bytes+empty_size.
3048 * We might not find them all in one contiguous area.
3049 *
3050 * returns zero and sets up cluster if things worked out, otherwise
3051 * it returns -enospc
3052 */
3053int btrfs_find_space_cluster(struct btrfs_block_group_cache *block_group,
 
3054			     struct btrfs_free_cluster *cluster,
3055			     u64 offset, u64 bytes, u64 empty_size)
3056{
3057	struct btrfs_fs_info *fs_info = block_group->fs_info;
3058	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
3059	struct btrfs_free_space *entry, *tmp;
3060	LIST_HEAD(bitmaps);
3061	u64 min_bytes;
3062	u64 cont1_bytes;
3063	int ret;
3064
3065	/*
3066	 * Choose the minimum extent size we'll require for this
3067	 * cluster.  For SSD_SPREAD, don't allow any fragmentation.
3068	 * For metadata, allow allocates with smaller extents.  For
3069	 * data, keep it dense.
3070	 */
3071	if (btrfs_test_opt(fs_info, SSD_SPREAD)) {
3072		cont1_bytes = min_bytes = bytes + empty_size;
3073	} else if (block_group->flags & BTRFS_BLOCK_GROUP_METADATA) {
3074		cont1_bytes = bytes;
3075		min_bytes = fs_info->sectorsize;
3076	} else {
3077		cont1_bytes = max(bytes, (bytes + empty_size) >> 2);
3078		min_bytes = fs_info->sectorsize;
3079	}
3080
3081	spin_lock(&ctl->tree_lock);
3082
3083	/*
3084	 * If we know we don't have enough space to make a cluster don't even
3085	 * bother doing all the work to try and find one.
3086	 */
3087	if (ctl->free_space < bytes) {
3088		spin_unlock(&ctl->tree_lock);
3089		return -ENOSPC;
3090	}
3091
3092	spin_lock(&cluster->lock);
3093
3094	/* someone already found a cluster, hooray */
3095	if (cluster->block_group) {
3096		ret = 0;
3097		goto out;
3098	}
3099
3100	trace_btrfs_find_cluster(block_group, offset, bytes, empty_size,
3101				 min_bytes);
3102
3103	ret = setup_cluster_no_bitmap(block_group, cluster, &bitmaps, offset,
3104				      bytes + empty_size,
3105				      cont1_bytes, min_bytes);
3106	if (ret)
3107		ret = setup_cluster_bitmap(block_group, cluster, &bitmaps,
3108					   offset, bytes + empty_size,
3109					   cont1_bytes, min_bytes);
3110
3111	/* Clear our temporary list */
3112	list_for_each_entry_safe(entry, tmp, &bitmaps, list)
3113		list_del_init(&entry->list);
3114
3115	if (!ret) {
3116		atomic_inc(&block_group->count);
3117		list_add_tail(&cluster->block_group_list,
3118			      &block_group->cluster_list);
3119		cluster->block_group = block_group;
3120	} else {
3121		trace_btrfs_failed_cluster_setup(block_group);
3122	}
3123out:
3124	spin_unlock(&cluster->lock);
3125	spin_unlock(&ctl->tree_lock);
3126
3127	return ret;
3128}
3129
3130/*
3131 * simple code to zero out a cluster
3132 */
3133void btrfs_init_free_cluster(struct btrfs_free_cluster *cluster)
3134{
3135	spin_lock_init(&cluster->lock);
3136	spin_lock_init(&cluster->refill_lock);
3137	cluster->root = RB_ROOT;
3138	cluster->max_size = 0;
3139	cluster->fragmented = false;
3140	INIT_LIST_HEAD(&cluster->block_group_list);
3141	cluster->block_group = NULL;
3142}
3143
3144static int do_trimming(struct btrfs_block_group_cache *block_group,
3145		       u64 *total_trimmed, u64 start, u64 bytes,
3146		       u64 reserved_start, u64 reserved_bytes,
3147		       struct btrfs_trim_range *trim_entry)
3148{
3149	struct btrfs_space_info *space_info = block_group->space_info;
3150	struct btrfs_fs_info *fs_info = block_group->fs_info;
3151	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
3152	int ret;
3153	int update = 0;
3154	u64 trimmed = 0;
3155
3156	spin_lock(&space_info->lock);
3157	spin_lock(&block_group->lock);
3158	if (!block_group->ro) {
3159		block_group->reserved += reserved_bytes;
3160		space_info->bytes_reserved += reserved_bytes;
3161		update = 1;
3162	}
3163	spin_unlock(&block_group->lock);
3164	spin_unlock(&space_info->lock);
3165
3166	ret = btrfs_discard_extent(fs_info, start, bytes, &trimmed);
3167	if (!ret)
3168		*total_trimmed += trimmed;
3169
3170	mutex_lock(&ctl->cache_writeout_mutex);
3171	btrfs_add_free_space(block_group, reserved_start, reserved_bytes);
3172	list_del(&trim_entry->list);
3173	mutex_unlock(&ctl->cache_writeout_mutex);
3174
3175	if (update) {
3176		spin_lock(&space_info->lock);
3177		spin_lock(&block_group->lock);
3178		if (block_group->ro)
3179			space_info->bytes_readonly += reserved_bytes;
3180		block_group->reserved -= reserved_bytes;
3181		space_info->bytes_reserved -= reserved_bytes;
3182		spin_unlock(&block_group->lock);
3183		spin_unlock(&space_info->lock);
 
3184	}
3185
3186	return ret;
3187}
3188
3189static int trim_no_bitmap(struct btrfs_block_group_cache *block_group,
3190			  u64 *total_trimmed, u64 start, u64 end, u64 minlen)
3191{
3192	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
3193	struct btrfs_free_space *entry;
3194	struct rb_node *node;
3195	int ret = 0;
3196	u64 extent_start;
3197	u64 extent_bytes;
3198	u64 bytes;
3199
3200	while (start < end) {
3201		struct btrfs_trim_range trim_entry;
3202
3203		mutex_lock(&ctl->cache_writeout_mutex);
3204		spin_lock(&ctl->tree_lock);
3205
3206		if (ctl->free_space < minlen) {
3207			spin_unlock(&ctl->tree_lock);
3208			mutex_unlock(&ctl->cache_writeout_mutex);
3209			break;
3210		}
3211
3212		entry = tree_search_offset(ctl, start, 0, 1);
3213		if (!entry) {
3214			spin_unlock(&ctl->tree_lock);
3215			mutex_unlock(&ctl->cache_writeout_mutex);
3216			break;
3217		}
3218
3219		/* skip bitmaps */
3220		while (entry->bitmap) {
3221			node = rb_next(&entry->offset_index);
3222			if (!node) {
3223				spin_unlock(&ctl->tree_lock);
3224				mutex_unlock(&ctl->cache_writeout_mutex);
3225				goto out;
3226			}
3227			entry = rb_entry(node, struct btrfs_free_space,
3228					 offset_index);
3229		}
3230
3231		if (entry->offset >= end) {
3232			spin_unlock(&ctl->tree_lock);
3233			mutex_unlock(&ctl->cache_writeout_mutex);
3234			break;
3235		}
3236
3237		extent_start = entry->offset;
3238		extent_bytes = entry->bytes;
3239		start = max(start, extent_start);
3240		bytes = min(extent_start + extent_bytes, end) - start;
3241		if (bytes < minlen) {
3242			spin_unlock(&ctl->tree_lock);
3243			mutex_unlock(&ctl->cache_writeout_mutex);
3244			goto next;
3245		}
3246
3247		unlink_free_space(ctl, entry);
3248		kmem_cache_free(btrfs_free_space_cachep, entry);
3249
3250		spin_unlock(&ctl->tree_lock);
3251		trim_entry.start = extent_start;
3252		trim_entry.bytes = extent_bytes;
3253		list_add_tail(&trim_entry.list, &ctl->trimming_ranges);
3254		mutex_unlock(&ctl->cache_writeout_mutex);
3255
3256		ret = do_trimming(block_group, total_trimmed, start, bytes,
3257				  extent_start, extent_bytes, &trim_entry);
3258		if (ret)
3259			break;
3260next:
3261		start += bytes;
3262
3263		if (fatal_signal_pending(current)) {
3264			ret = -ERESTARTSYS;
3265			break;
3266		}
3267
3268		cond_resched();
3269	}
3270out:
3271	return ret;
3272}
3273
3274static int trim_bitmaps(struct btrfs_block_group_cache *block_group,
3275			u64 *total_trimmed, u64 start, u64 end, u64 minlen)
3276{
3277	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
3278	struct btrfs_free_space *entry;
3279	int ret = 0;
3280	int ret2;
3281	u64 bytes;
3282	u64 offset = offset_to_bitmap(ctl, start);
3283
3284	while (offset < end) {
3285		bool next_bitmap = false;
3286		struct btrfs_trim_range trim_entry;
3287
3288		mutex_lock(&ctl->cache_writeout_mutex);
3289		spin_lock(&ctl->tree_lock);
3290
3291		if (ctl->free_space < minlen) {
3292			spin_unlock(&ctl->tree_lock);
3293			mutex_unlock(&ctl->cache_writeout_mutex);
3294			break;
3295		}
3296
3297		entry = tree_search_offset(ctl, offset, 1, 0);
3298		if (!entry) {
3299			spin_unlock(&ctl->tree_lock);
3300			mutex_unlock(&ctl->cache_writeout_mutex);
3301			next_bitmap = true;
3302			goto next;
3303		}
3304
3305		bytes = minlen;
3306		ret2 = search_bitmap(ctl, entry, &start, &bytes, false);
3307		if (ret2 || start >= end) {
3308			spin_unlock(&ctl->tree_lock);
3309			mutex_unlock(&ctl->cache_writeout_mutex);
3310			next_bitmap = true;
3311			goto next;
3312		}
3313
3314		bytes = min(bytes, end - start);
3315		if (bytes < minlen) {
3316			spin_unlock(&ctl->tree_lock);
3317			mutex_unlock(&ctl->cache_writeout_mutex);
3318			goto next;
3319		}
3320
3321		bitmap_clear_bits(ctl, entry, start, bytes);
3322		if (entry->bytes == 0)
3323			free_bitmap(ctl, entry);
3324
3325		spin_unlock(&ctl->tree_lock);
3326		trim_entry.start = start;
3327		trim_entry.bytes = bytes;
3328		list_add_tail(&trim_entry.list, &ctl->trimming_ranges);
3329		mutex_unlock(&ctl->cache_writeout_mutex);
3330
3331		ret = do_trimming(block_group, total_trimmed, start, bytes,
3332				  start, bytes, &trim_entry);
3333		if (ret)
3334			break;
3335next:
3336		if (next_bitmap) {
3337			offset += BITS_PER_BITMAP * ctl->unit;
3338		} else {
3339			start += bytes;
3340			if (start >= offset + BITS_PER_BITMAP * ctl->unit)
3341				offset += BITS_PER_BITMAP * ctl->unit;
3342		}
3343
3344		if (fatal_signal_pending(current)) {
3345			ret = -ERESTARTSYS;
3346			break;
3347		}
3348
3349		cond_resched();
3350	}
3351
3352	return ret;
3353}
3354
3355void btrfs_get_block_group_trimming(struct btrfs_block_group_cache *cache)
3356{
3357	atomic_inc(&cache->trimming);
3358}
3359
3360void btrfs_put_block_group_trimming(struct btrfs_block_group_cache *block_group)
3361{
3362	struct btrfs_fs_info *fs_info = block_group->fs_info;
3363	struct extent_map_tree *em_tree;
3364	struct extent_map *em;
3365	bool cleanup;
3366
3367	spin_lock(&block_group->lock);
3368	cleanup = (atomic_dec_and_test(&block_group->trimming) &&
3369		   block_group->removed);
3370	spin_unlock(&block_group->lock);
3371
3372	if (cleanup) {
3373		mutex_lock(&fs_info->chunk_mutex);
3374		em_tree = &fs_info->mapping_tree;
3375		write_lock(&em_tree->lock);
3376		em = lookup_extent_mapping(em_tree, block_group->key.objectid,
3377					   1);
3378		BUG_ON(!em); /* logic error, can't happen */
 
 
 
 
3379		remove_extent_mapping(em_tree, em);
3380		write_unlock(&em_tree->lock);
3381		mutex_unlock(&fs_info->chunk_mutex);
3382
3383		/* once for us and once for the tree */
3384		free_extent_map(em);
3385		free_extent_map(em);
3386
3387		/*
3388		 * We've left one free space entry and other tasks trimming
3389		 * this block group have left 1 entry each one. Free them.
3390		 */
3391		__btrfs_remove_free_space_cache(block_group->free_space_ctl);
3392	}
3393}
3394
3395int btrfs_trim_block_group(struct btrfs_block_group_cache *block_group,
3396			   u64 *trimmed, u64 start, u64 end, u64 minlen)
3397{
3398	int ret;
3399
3400	*trimmed = 0;
3401
3402	spin_lock(&block_group->lock);
3403	if (block_group->removed) {
3404		spin_unlock(&block_group->lock);
3405		return 0;
3406	}
3407	btrfs_get_block_group_trimming(block_group);
3408	spin_unlock(&block_group->lock);
3409
3410	ret = trim_no_bitmap(block_group, trimmed, start, end, minlen);
3411	if (ret)
3412		goto out;
3413
3414	ret = trim_bitmaps(block_group, trimmed, start, end, minlen);
3415out:
3416	btrfs_put_block_group_trimming(block_group);
3417	return ret;
3418}
3419
3420/*
3421 * Find the left-most item in the cache tree, and then return the
3422 * smallest inode number in the item.
3423 *
3424 * Note: the returned inode number may not be the smallest one in
3425 * the tree, if the left-most item is a bitmap.
3426 */
3427u64 btrfs_find_ino_for_alloc(struct btrfs_root *fs_root)
3428{
3429	struct btrfs_free_space_ctl *ctl = fs_root->free_ino_ctl;
3430	struct btrfs_free_space *entry = NULL;
3431	u64 ino = 0;
3432
3433	spin_lock(&ctl->tree_lock);
3434
3435	if (RB_EMPTY_ROOT(&ctl->free_space_offset))
3436		goto out;
3437
3438	entry = rb_entry(rb_first(&ctl->free_space_offset),
3439			 struct btrfs_free_space, offset_index);
3440
3441	if (!entry->bitmap) {
3442		ino = entry->offset;
3443
3444		unlink_free_space(ctl, entry);
3445		entry->offset++;
3446		entry->bytes--;
3447		if (!entry->bytes)
3448			kmem_cache_free(btrfs_free_space_cachep, entry);
3449		else
3450			link_free_space(ctl, entry);
3451	} else {
3452		u64 offset = 0;
3453		u64 count = 1;
3454		int ret;
3455
3456		ret = search_bitmap(ctl, entry, &offset, &count, true);
3457		/* Logic error; Should be empty if it can't find anything */
3458		ASSERT(!ret);
3459
3460		ino = offset;
3461		bitmap_clear_bits(ctl, entry, offset, 1);
3462		if (entry->bytes == 0)
3463			free_bitmap(ctl, entry);
3464	}
3465out:
3466	spin_unlock(&ctl->tree_lock);
3467
3468	return ino;
3469}
3470
3471struct inode *lookup_free_ino_inode(struct btrfs_root *root,
3472				    struct btrfs_path *path)
3473{
3474	struct inode *inode = NULL;
3475
3476	spin_lock(&root->ino_cache_lock);
3477	if (root->ino_cache_inode)
3478		inode = igrab(root->ino_cache_inode);
3479	spin_unlock(&root->ino_cache_lock);
3480	if (inode)
3481		return inode;
3482
3483	inode = __lookup_free_space_inode(root, path, 0);
3484	if (IS_ERR(inode))
3485		return inode;
3486
3487	spin_lock(&root->ino_cache_lock);
3488	if (!btrfs_fs_closing(root->fs_info))
3489		root->ino_cache_inode = igrab(inode);
3490	spin_unlock(&root->ino_cache_lock);
3491
3492	return inode;
3493}
3494
3495int create_free_ino_inode(struct btrfs_root *root,
3496			  struct btrfs_trans_handle *trans,
3497			  struct btrfs_path *path)
3498{
3499	return __create_free_space_inode(root, trans, path,
3500					 BTRFS_FREE_INO_OBJECTID, 0);
3501}
3502
3503int load_free_ino_cache(struct btrfs_fs_info *fs_info, struct btrfs_root *root)
3504{
3505	struct btrfs_free_space_ctl *ctl = root->free_ino_ctl;
3506	struct btrfs_path *path;
3507	struct inode *inode;
3508	int ret = 0;
3509	u64 root_gen = btrfs_root_generation(&root->root_item);
3510
3511	if (!btrfs_test_opt(fs_info, INODE_MAP_CACHE))
3512		return 0;
3513
3514	/*
3515	 * If we're unmounting then just return, since this does a search on the
3516	 * normal root and not the commit root and we could deadlock.
3517	 */
3518	if (btrfs_fs_closing(fs_info))
3519		return 0;
3520
3521	path = btrfs_alloc_path();
3522	if (!path)
3523		return 0;
3524
3525	inode = lookup_free_ino_inode(root, path);
3526	if (IS_ERR(inode))
3527		goto out;
3528
3529	if (root_gen != BTRFS_I(inode)->generation)
3530		goto out_put;
3531
3532	ret = __load_free_space_cache(root, inode, ctl, path, 0);
3533
3534	if (ret < 0)
3535		btrfs_err(fs_info,
3536			"failed to load free ino cache for root %llu",
3537			root->root_key.objectid);
3538out_put:
3539	iput(inode);
3540out:
3541	btrfs_free_path(path);
3542	return ret;
3543}
3544
3545int btrfs_write_out_ino_cache(struct btrfs_root *root,
3546			      struct btrfs_trans_handle *trans,
3547			      struct btrfs_path *path,
3548			      struct inode *inode)
3549{
3550	struct btrfs_fs_info *fs_info = root->fs_info;
3551	struct btrfs_free_space_ctl *ctl = root->free_ino_ctl;
3552	int ret;
3553	struct btrfs_io_ctl io_ctl;
3554	bool release_metadata = true;
3555
3556	if (!btrfs_test_opt(fs_info, INODE_MAP_CACHE))
3557		return 0;
3558
3559	memset(&io_ctl, 0, sizeof(io_ctl));
3560	ret = __btrfs_write_out_cache(root, inode, ctl, NULL, &io_ctl, trans);
 
3561	if (!ret) {
3562		/*
3563		 * At this point writepages() didn't error out, so our metadata
3564		 * reservation is released when the writeback finishes, at
3565		 * inode.c:btrfs_finish_ordered_io(), regardless of it finishing
3566		 * with or without an error.
3567		 */
3568		release_metadata = false;
3569		ret = btrfs_wait_cache_io_root(root, trans, &io_ctl, path);
3570	}
3571
3572	if (ret) {
3573		if (release_metadata)
3574			btrfs_delalloc_release_metadata(BTRFS_I(inode),
3575					inode->i_size, true);
3576#ifdef DEBUG
3577		btrfs_err(fs_info,
3578			  "failed to write free ino cache for root %llu",
3579			  root->root_key.objectid);
3580#endif
3581	}
3582
3583	return ret;
3584}
3585
3586#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
3587/*
3588 * Use this if you need to make a bitmap or extent entry specifically, it
3589 * doesn't do any of the merging that add_free_space does, this acts a lot like
3590 * how the free space cache loading stuff works, so you can get really weird
3591 * configurations.
3592 */
3593int test_add_free_space_entry(struct btrfs_block_group_cache *cache,
3594			      u64 offset, u64 bytes, bool bitmap)
3595{
3596	struct btrfs_free_space_ctl *ctl = cache->free_space_ctl;
3597	struct btrfs_free_space *info = NULL, *bitmap_info;
3598	void *map = NULL;
3599	u64 bytes_added;
3600	int ret;
3601
3602again:
3603	if (!info) {
3604		info = kmem_cache_zalloc(btrfs_free_space_cachep, GFP_NOFS);
3605		if (!info)
3606			return -ENOMEM;
3607	}
3608
3609	if (!bitmap) {
3610		spin_lock(&ctl->tree_lock);
3611		info->offset = offset;
3612		info->bytes = bytes;
3613		info->max_extent_size = 0;
3614		ret = link_free_space(ctl, info);
3615		spin_unlock(&ctl->tree_lock);
3616		if (ret)
3617			kmem_cache_free(btrfs_free_space_cachep, info);
3618		return ret;
3619	}
3620
3621	if (!map) {
3622		map = kmem_cache_zalloc(btrfs_free_space_bitmap_cachep, GFP_NOFS);
3623		if (!map) {
3624			kmem_cache_free(btrfs_free_space_cachep, info);
3625			return -ENOMEM;
3626		}
3627	}
3628
3629	spin_lock(&ctl->tree_lock);
3630	bitmap_info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
3631					 1, 0);
3632	if (!bitmap_info) {
3633		info->bitmap = map;
3634		map = NULL;
3635		add_new_bitmap(ctl, info, offset);
3636		bitmap_info = info;
3637		info = NULL;
3638	}
3639
3640	bytes_added = add_bytes_to_bitmap(ctl, bitmap_info, offset, bytes);
3641
3642	bytes -= bytes_added;
3643	offset += bytes_added;
3644	spin_unlock(&ctl->tree_lock);
3645
3646	if (bytes)
3647		goto again;
3648
3649	if (info)
3650		kmem_cache_free(btrfs_free_space_cachep, info);
3651	if (map)
3652		kmem_cache_free(btrfs_free_space_bitmap_cachep, map);
3653	return 0;
3654}
3655
3656/*
3657 * Checks to see if the given range is in the free space cache.  This is really
3658 * just used to check the absence of space, so if there is free space in the
3659 * range at all we will return 1.
3660 */
3661int test_check_exists(struct btrfs_block_group_cache *cache,
3662		      u64 offset, u64 bytes)
3663{
3664	struct btrfs_free_space_ctl *ctl = cache->free_space_ctl;
3665	struct btrfs_free_space *info;
3666	int ret = 0;
3667
3668	spin_lock(&ctl->tree_lock);
3669	info = tree_search_offset(ctl, offset, 0, 0);
3670	if (!info) {
3671		info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
3672					  1, 0);
3673		if (!info)
3674			goto out;
3675	}
3676
3677have_info:
3678	if (info->bitmap) {
3679		u64 bit_off, bit_bytes;
3680		struct rb_node *n;
3681		struct btrfs_free_space *tmp;
3682
3683		bit_off = offset;
3684		bit_bytes = ctl->unit;
3685		ret = search_bitmap(ctl, info, &bit_off, &bit_bytes, false);
3686		if (!ret) {
3687			if (bit_off == offset) {
3688				ret = 1;
3689				goto out;
3690			} else if (bit_off > offset &&
3691				   offset + bytes > bit_off) {
3692				ret = 1;
3693				goto out;
3694			}
3695		}
3696
3697		n = rb_prev(&info->offset_index);
3698		while (n) {
3699			tmp = rb_entry(n, struct btrfs_free_space,
3700				       offset_index);
3701			if (tmp->offset + tmp->bytes < offset)
3702				break;
3703			if (offset + bytes < tmp->offset) {
3704				n = rb_prev(&tmp->offset_index);
3705				continue;
3706			}
3707			info = tmp;
3708			goto have_info;
3709		}
3710
3711		n = rb_next(&info->offset_index);
3712		while (n) {
3713			tmp = rb_entry(n, struct btrfs_free_space,
3714				       offset_index);
3715			if (offset + bytes < tmp->offset)
3716				break;
3717			if (tmp->offset + tmp->bytes < offset) {
3718				n = rb_next(&tmp->offset_index);
3719				continue;
3720			}
3721			info = tmp;
3722			goto have_info;
3723		}
3724
3725		ret = 0;
3726		goto out;
3727	}
3728
3729	if (info->offset == offset) {
3730		ret = 1;
3731		goto out;
3732	}
3733
3734	if (offset > info->offset && offset < info->offset + info->bytes)
3735		ret = 1;
3736out:
3737	spin_unlock(&ctl->tree_lock);
3738	return ret;
3739}
3740#endif /* CONFIG_BTRFS_FS_RUN_SANITY_TESTS */