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v6.8
   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 "fs.h"
  16#include "messages.h"
  17#include "misc.h"
  18#include "free-space-cache.h"
  19#include "transaction.h"
  20#include "disk-io.h"
  21#include "extent_io.h"
  22#include "volumes.h"
  23#include "space-info.h"
  24#include "delalloc-space.h"
  25#include "block-group.h"
  26#include "discard.h"
  27#include "subpage.h"
  28#include "inode-item.h"
  29#include "accessors.h"
  30#include "file-item.h"
  31#include "file.h"
  32#include "super.h"
  33
  34#define BITS_PER_BITMAP		(PAGE_SIZE * 8UL)
  35#define MAX_CACHE_BYTES_PER_GIG	SZ_64K
  36#define FORCE_EXTENT_THRESHOLD	SZ_1M
  37
  38static struct kmem_cache *btrfs_free_space_cachep;
  39static struct kmem_cache *btrfs_free_space_bitmap_cachep;
  40
  41struct btrfs_trim_range {
  42	u64 start;
  43	u64 bytes;
  44	struct list_head list;
  45};
  46
  47static int link_free_space(struct btrfs_free_space_ctl *ctl,
  48			   struct btrfs_free_space *info);
  49static void unlink_free_space(struct btrfs_free_space_ctl *ctl,
  50			      struct btrfs_free_space *info, bool update_stat);
  51static int search_bitmap(struct btrfs_free_space_ctl *ctl,
  52			 struct btrfs_free_space *bitmap_info, u64 *offset,
  53			 u64 *bytes, bool for_alloc);
  54static void free_bitmap(struct btrfs_free_space_ctl *ctl,
  55			struct btrfs_free_space *bitmap_info);
  56static void bitmap_clear_bits(struct btrfs_free_space_ctl *ctl,
  57			      struct btrfs_free_space *info, u64 offset,
  58			      u64 bytes, bool update_stats);
  59
  60static void btrfs_crc32c_final(u32 crc, u8 *result)
  61{
  62	put_unaligned_le32(~crc, result);
  63}
  64
  65static void __btrfs_remove_free_space_cache(struct btrfs_free_space_ctl *ctl)
  66{
  67	struct btrfs_free_space *info;
  68	struct rb_node *node;
  69
  70	while ((node = rb_last(&ctl->free_space_offset)) != NULL) {
  71		info = rb_entry(node, struct btrfs_free_space, offset_index);
  72		if (!info->bitmap) {
  73			unlink_free_space(ctl, info, true);
  74			kmem_cache_free(btrfs_free_space_cachep, info);
  75		} else {
  76			free_bitmap(ctl, info);
  77		}
  78
  79		cond_resched_lock(&ctl->tree_lock);
  80	}
  81}
  82
  83static struct inode *__lookup_free_space_inode(struct btrfs_root *root,
  84					       struct btrfs_path *path,
  85					       u64 offset)
  86{
  87	struct btrfs_fs_info *fs_info = root->fs_info;
  88	struct btrfs_key key;
  89	struct btrfs_key location;
  90	struct btrfs_disk_key disk_key;
  91	struct btrfs_free_space_header *header;
  92	struct extent_buffer *leaf;
  93	struct inode *inode = NULL;
  94	unsigned nofs_flag;
  95	int ret;
  96
  97	key.objectid = BTRFS_FREE_SPACE_OBJECTID;
  98	key.offset = offset;
  99	key.type = 0;
 100
 101	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
 102	if (ret < 0)
 103		return ERR_PTR(ret);
 104	if (ret > 0) {
 105		btrfs_release_path(path);
 106		return ERR_PTR(-ENOENT);
 107	}
 108
 109	leaf = path->nodes[0];
 110	header = btrfs_item_ptr(leaf, path->slots[0],
 111				struct btrfs_free_space_header);
 112	btrfs_free_space_key(leaf, header, &disk_key);
 113	btrfs_disk_key_to_cpu(&location, &disk_key);
 114	btrfs_release_path(path);
 115
 116	/*
 117	 * We are often under a trans handle at this point, so we need to make
 118	 * sure NOFS is set to keep us from deadlocking.
 119	 */
 120	nofs_flag = memalloc_nofs_save();
 121	inode = btrfs_iget_path(fs_info->sb, location.objectid, root, path);
 122	btrfs_release_path(path);
 123	memalloc_nofs_restore(nofs_flag);
 124	if (IS_ERR(inode))
 125		return inode;
 
 
 
 
 126
 127	mapping_set_gfp_mask(inode->i_mapping,
 128			mapping_gfp_constraint(inode->i_mapping,
 129			~(__GFP_FS | __GFP_HIGHMEM)));
 130
 131	return inode;
 132}
 133
 134struct inode *lookup_free_space_inode(struct btrfs_block_group *block_group,
 135		struct btrfs_path *path)
 
 136{
 137	struct btrfs_fs_info *fs_info = block_group->fs_info;
 138	struct inode *inode = NULL;
 139	u32 flags = BTRFS_INODE_NODATASUM | BTRFS_INODE_NODATACOW;
 140
 141	spin_lock(&block_group->lock);
 142	if (block_group->inode)
 143		inode = igrab(block_group->inode);
 144	spin_unlock(&block_group->lock);
 145	if (inode)
 146		return inode;
 147
 148	inode = __lookup_free_space_inode(fs_info->tree_root, path,
 149					  block_group->start);
 150	if (IS_ERR(inode))
 151		return inode;
 152
 153	spin_lock(&block_group->lock);
 154	if (!((BTRFS_I(inode)->flags & flags) == flags)) {
 155		btrfs_info(fs_info, "Old style space inode found, converting.");
 156		BTRFS_I(inode)->flags |= BTRFS_INODE_NODATASUM |
 157			BTRFS_INODE_NODATACOW;
 158		block_group->disk_cache_state = BTRFS_DC_CLEAR;
 159	}
 160
 161	if (!test_and_set_bit(BLOCK_GROUP_FLAG_IREF, &block_group->runtime_flags))
 162		block_group->inode = igrab(inode);
 
 
 163	spin_unlock(&block_group->lock);
 164
 165	return inode;
 166}
 167
 168static int __create_free_space_inode(struct btrfs_root *root,
 169				     struct btrfs_trans_handle *trans,
 170				     struct btrfs_path *path,
 171				     u64 ino, u64 offset)
 172{
 173	struct btrfs_key key;
 174	struct btrfs_disk_key disk_key;
 175	struct btrfs_free_space_header *header;
 176	struct btrfs_inode_item *inode_item;
 177	struct extent_buffer *leaf;
 178	/* We inline CRCs for the free disk space cache */
 179	const u64 flags = BTRFS_INODE_NOCOMPRESS | BTRFS_INODE_PREALLOC |
 180			  BTRFS_INODE_NODATASUM | BTRFS_INODE_NODATACOW;
 181	int ret;
 182
 183	ret = btrfs_insert_empty_inode(trans, root, path, ino);
 184	if (ret)
 185		return ret;
 186
 
 
 
 
 187	leaf = path->nodes[0];
 188	inode_item = btrfs_item_ptr(leaf, path->slots[0],
 189				    struct btrfs_inode_item);
 190	btrfs_item_key(leaf, &disk_key, path->slots[0]);
 191	memzero_extent_buffer(leaf, (unsigned long)inode_item,
 192			     sizeof(*inode_item));
 193	btrfs_set_inode_generation(leaf, inode_item, trans->transid);
 194	btrfs_set_inode_size(leaf, inode_item, 0);
 195	btrfs_set_inode_nbytes(leaf, inode_item, 0);
 196	btrfs_set_inode_uid(leaf, inode_item, 0);
 197	btrfs_set_inode_gid(leaf, inode_item, 0);
 198	btrfs_set_inode_mode(leaf, inode_item, S_IFREG | 0600);
 199	btrfs_set_inode_flags(leaf, inode_item, flags);
 200	btrfs_set_inode_nlink(leaf, inode_item, 1);
 201	btrfs_set_inode_transid(leaf, inode_item, trans->transid);
 202	btrfs_set_inode_block_group(leaf, inode_item, offset);
 203	btrfs_mark_buffer_dirty(trans, leaf);
 204	btrfs_release_path(path);
 205
 206	key.objectid = BTRFS_FREE_SPACE_OBJECTID;
 207	key.offset = offset;
 208	key.type = 0;
 
 209	ret = btrfs_insert_empty_item(trans, root, path, &key,
 210				      sizeof(struct btrfs_free_space_header));
 211	if (ret < 0) {
 212		btrfs_release_path(path);
 213		return ret;
 214	}
 215
 216	leaf = path->nodes[0];
 217	header = btrfs_item_ptr(leaf, path->slots[0],
 218				struct btrfs_free_space_header);
 219	memzero_extent_buffer(leaf, (unsigned long)header, sizeof(*header));
 220	btrfs_set_free_space_key(leaf, header, &disk_key);
 221	btrfs_mark_buffer_dirty(trans, leaf);
 222	btrfs_release_path(path);
 223
 224	return 0;
 225}
 226
 227int create_free_space_inode(struct btrfs_trans_handle *trans,
 228			    struct btrfs_block_group *block_group,
 
 229			    struct btrfs_path *path)
 230{
 231	int ret;
 232	u64 ino;
 233
 234	ret = btrfs_get_free_objectid(trans->fs_info->tree_root, &ino);
 235	if (ret < 0)
 236		return ret;
 237
 238	return __create_free_space_inode(trans->fs_info->tree_root, trans, path,
 239					 ino, block_group->start);
 240}
 241
 242/*
 243 * inode is an optional sink: if it is NULL, btrfs_remove_free_space_inode
 244 * handles lookup, otherwise it takes ownership and iputs the inode.
 245 * Don't reuse an inode pointer after passing it into this function.
 246 */
 247int btrfs_remove_free_space_inode(struct btrfs_trans_handle *trans,
 248				  struct inode *inode,
 249				  struct btrfs_block_group *block_group)
 250{
 251	struct btrfs_path *path;
 252	struct btrfs_key key;
 253	int ret = 0;
 254
 255	path = btrfs_alloc_path();
 256	if (!path)
 257		return -ENOMEM;
 258
 259	if (!inode)
 260		inode = lookup_free_space_inode(block_group, path);
 261	if (IS_ERR(inode)) {
 262		if (PTR_ERR(inode) != -ENOENT)
 263			ret = PTR_ERR(inode);
 264		goto out;
 265	}
 266	ret = btrfs_orphan_add(trans, BTRFS_I(inode));
 267	if (ret) {
 268		btrfs_add_delayed_iput(BTRFS_I(inode));
 269		goto out;
 270	}
 271	clear_nlink(inode);
 272	/* One for the block groups ref */
 273	spin_lock(&block_group->lock);
 274	if (test_and_clear_bit(BLOCK_GROUP_FLAG_IREF, &block_group->runtime_flags)) {
 275		block_group->inode = NULL;
 276		spin_unlock(&block_group->lock);
 277		iput(inode);
 278	} else {
 279		spin_unlock(&block_group->lock);
 280	}
 281	/* One for the lookup ref */
 282	btrfs_add_delayed_iput(BTRFS_I(inode));
 283
 284	key.objectid = BTRFS_FREE_SPACE_OBJECTID;
 285	key.type = 0;
 286	key.offset = block_group->start;
 287	ret = btrfs_search_slot(trans, trans->fs_info->tree_root, &key, path,
 288				-1, 1);
 289	if (ret) {
 290		if (ret > 0)
 291			ret = 0;
 292		goto out;
 293	}
 294	ret = btrfs_del_item(trans, trans->fs_info->tree_root, path);
 295out:
 296	btrfs_free_path(path);
 297	return ret;
 298}
 299
 300int btrfs_truncate_free_space_cache(struct btrfs_trans_handle *trans,
 301				    struct btrfs_block_group *block_group,
 302				    struct inode *vfs_inode)
 303{
 304	struct btrfs_truncate_control control = {
 305		.inode = BTRFS_I(vfs_inode),
 306		.new_size = 0,
 307		.ino = btrfs_ino(BTRFS_I(vfs_inode)),
 308		.min_type = BTRFS_EXTENT_DATA_KEY,
 309		.clear_extent_range = true,
 310	};
 311	struct btrfs_inode *inode = BTRFS_I(vfs_inode);
 312	struct btrfs_root *root = inode->root;
 313	struct extent_state *cached_state = NULL;
 314	int ret = 0;
 315	bool locked = false;
 316
 317	if (block_group) {
 318		struct btrfs_path *path = btrfs_alloc_path();
 319
 320		if (!path) {
 321			ret = -ENOMEM;
 322			goto fail;
 323		}
 324		locked = true;
 325		mutex_lock(&trans->transaction->cache_write_mutex);
 326		if (!list_empty(&block_group->io_list)) {
 327			list_del_init(&block_group->io_list);
 328
 329			btrfs_wait_cache_io(trans, block_group, path);
 330			btrfs_put_block_group(block_group);
 331		}
 332
 333		/*
 334		 * now that we've truncated the cache away, its no longer
 335		 * setup or written
 336		 */
 337		spin_lock(&block_group->lock);
 338		block_group->disk_cache_state = BTRFS_DC_CLEAR;
 339		spin_unlock(&block_group->lock);
 340		btrfs_free_path(path);
 341	}
 
 342
 
 343	btrfs_i_size_write(inode, 0);
 344	truncate_pagecache(vfs_inode, 0);
 345
 346	lock_extent(&inode->io_tree, 0, (u64)-1, &cached_state);
 347	btrfs_drop_extent_map_range(inode, 0, (u64)-1, false);
 348
 349	/*
 350	 * We skip the throttling logic for free space cache inodes, so we don't
 351	 * need to check for -EAGAIN.
 352	 */
 353	ret = btrfs_truncate_inode_items(trans, root, &control);
 354
 355	inode_sub_bytes(&inode->vfs_inode, control.sub_bytes);
 356	btrfs_inode_safe_disk_i_size_write(inode, control.last_size);
 357
 358	unlock_extent(&inode->io_tree, 0, (u64)-1, &cached_state);
 359	if (ret)
 360		goto fail;
 361
 362	ret = btrfs_update_inode(trans, inode);
 363
 364fail:
 365	if (locked)
 366		mutex_unlock(&trans->transaction->cache_write_mutex);
 367	if (ret)
 368		btrfs_abort_transaction(trans, ret);
 
 369
 370	return ret;
 371}
 372
 373static void readahead_cache(struct inode *inode)
 374{
 375	struct file_ra_state ra;
 376	unsigned long last_index;
 377
 378	file_ra_state_init(&ra, inode->i_mapping);
 379	last_index = (i_size_read(inode) - 1) >> PAGE_SHIFT;
 
 380
 381	page_cache_sync_readahead(inode->i_mapping, &ra, NULL, 0, last_index);
 382}
 383
 384static int io_ctl_init(struct btrfs_io_ctl *io_ctl, struct inode *inode,
 385		       int write)
 386{
 387	int num_pages;
 388
 389	num_pages = DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE);
 390
 391	/* Make sure we can fit our crcs and generation into the first page */
 392	if (write && (num_pages * sizeof(u32) + sizeof(u64)) > PAGE_SIZE)
 393		return -ENOSPC;
 394
 395	memset(io_ctl, 0, sizeof(struct btrfs_io_ctl));
 
 
 
 
 
 
 
 
 
 396
 397	io_ctl->pages = kcalloc(num_pages, sizeof(struct page *), GFP_NOFS);
 
 
 
 
 
 
 
 398	if (!io_ctl->pages)
 399		return -ENOMEM;
 400
 401	io_ctl->num_pages = num_pages;
 402	io_ctl->fs_info = btrfs_sb(inode->i_sb);
 403	io_ctl->inode = inode;
 404
 405	return 0;
 406}
 407ALLOW_ERROR_INJECTION(io_ctl_init, ERRNO);
 408
 409static void io_ctl_free(struct btrfs_io_ctl *io_ctl)
 410{
 411	kfree(io_ctl->pages);
 412	io_ctl->pages = NULL;
 413}
 414
 415static void io_ctl_unmap_page(struct btrfs_io_ctl *io_ctl)
 416{
 417	if (io_ctl->cur) {
 
 418		io_ctl->cur = NULL;
 419		io_ctl->orig = NULL;
 420	}
 421}
 422
 423static void io_ctl_map_page(struct btrfs_io_ctl *io_ctl, int clear)
 424{
 425	ASSERT(io_ctl->index < io_ctl->num_pages);
 
 426	io_ctl->page = io_ctl->pages[io_ctl->index++];
 427	io_ctl->cur = page_address(io_ctl->page);
 428	io_ctl->orig = io_ctl->cur;
 429	io_ctl->size = PAGE_SIZE;
 430	if (clear)
 431		clear_page(io_ctl->cur);
 432}
 433
 434static void io_ctl_drop_pages(struct btrfs_io_ctl *io_ctl)
 435{
 436	int i;
 437
 438	io_ctl_unmap_page(io_ctl);
 439
 440	for (i = 0; i < io_ctl->num_pages; i++) {
 441		if (io_ctl->pages[i]) {
 442			btrfs_folio_clear_checked(io_ctl->fs_info,
 443					page_folio(io_ctl->pages[i]),
 444					page_offset(io_ctl->pages[i]),
 445					PAGE_SIZE);
 446			unlock_page(io_ctl->pages[i]);
 447			put_page(io_ctl->pages[i]);
 448		}
 449	}
 450}
 451
 452static int io_ctl_prepare_pages(struct btrfs_io_ctl *io_ctl, bool uptodate)
 
 453{
 454	struct page *page;
 455	struct inode *inode = io_ctl->inode;
 456	gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
 457	int i;
 458
 459	for (i = 0; i < io_ctl->num_pages; i++) {
 460		int ret;
 461
 462		page = find_or_create_page(inode->i_mapping, i, mask);
 463		if (!page) {
 464			io_ctl_drop_pages(io_ctl);
 465			return -ENOMEM;
 466		}
 467
 468		ret = set_page_extent_mapped(page);
 469		if (ret < 0) {
 470			unlock_page(page);
 471			put_page(page);
 472			io_ctl_drop_pages(io_ctl);
 473			return ret;
 474		}
 475
 476		io_ctl->pages[i] = page;
 477		if (uptodate && !PageUptodate(page)) {
 478			btrfs_read_folio(NULL, page_folio(page));
 479			lock_page(page);
 480			if (page->mapping != inode->i_mapping) {
 481				btrfs_err(BTRFS_I(inode)->root->fs_info,
 482					  "free space cache page truncated");
 483				io_ctl_drop_pages(io_ctl);
 484				return -EIO;
 485			}
 486			if (!PageUptodate(page)) {
 487				btrfs_err(BTRFS_I(inode)->root->fs_info,
 488					   "error reading free space cache");
 489				io_ctl_drop_pages(io_ctl);
 490				return -EIO;
 491			}
 492		}
 493	}
 494
 495	for (i = 0; i < io_ctl->num_pages; i++)
 496		clear_page_dirty_for_io(io_ctl->pages[i]);
 
 
 497
 498	return 0;
 499}
 500
 501static void io_ctl_set_generation(struct btrfs_io_ctl *io_ctl, u64 generation)
 502{
 
 
 503	io_ctl_map_page(io_ctl, 1);
 504
 505	/*
 506	 * Skip the csum areas.  If we don't check crcs then we just have a
 507	 * 64bit chunk at the front of the first page.
 508	 */
 509	io_ctl->cur += (sizeof(u32) * io_ctl->num_pages);
 510	io_ctl->size -= sizeof(u64) + (sizeof(u32) * io_ctl->num_pages);
 
 
 
 
 
 511
 512	put_unaligned_le64(generation, io_ctl->cur);
 
 513	io_ctl->cur += sizeof(u64);
 514}
 515
 516static int io_ctl_check_generation(struct btrfs_io_ctl *io_ctl, u64 generation)
 517{
 518	u64 cache_gen;
 519
 520	/*
 521	 * Skip the crc area.  If we don't check crcs then we just have a 64bit
 522	 * chunk at the front of the first page.
 523	 */
 524	io_ctl->cur += sizeof(u32) * io_ctl->num_pages;
 525	io_ctl->size -= sizeof(u64) + (sizeof(u32) * io_ctl->num_pages);
 
 
 
 
 
 
 526
 527	cache_gen = get_unaligned_le64(io_ctl->cur);
 528	if (cache_gen != generation) {
 529		btrfs_err_rl(io_ctl->fs_info,
 530			"space cache generation (%llu) does not match inode (%llu)",
 531				cache_gen, generation);
 532		io_ctl_unmap_page(io_ctl);
 533		return -EIO;
 534	}
 535	io_ctl->cur += sizeof(u64);
 536	return 0;
 537}
 538
 539static void io_ctl_set_crc(struct btrfs_io_ctl *io_ctl, int index)
 540{
 541	u32 *tmp;
 542	u32 crc = ~(u32)0;
 543	unsigned offset = 0;
 544
 
 
 
 
 
 545	if (index == 0)
 546		offset = sizeof(u32) * io_ctl->num_pages;
 547
 548	crc = crc32c(crc, io_ctl->orig + offset, PAGE_SIZE - offset);
 549	btrfs_crc32c_final(crc, (u8 *)&crc);
 
 550	io_ctl_unmap_page(io_ctl);
 551	tmp = page_address(io_ctl->pages[0]);
 552	tmp += index;
 553	*tmp = crc;
 
 554}
 555
 556static int io_ctl_check_crc(struct btrfs_io_ctl *io_ctl, int index)
 557{
 558	u32 *tmp, val;
 559	u32 crc = ~(u32)0;
 560	unsigned offset = 0;
 561
 
 
 
 
 
 562	if (index == 0)
 563		offset = sizeof(u32) * io_ctl->num_pages;
 564
 565	tmp = page_address(io_ctl->pages[0]);
 566	tmp += index;
 567	val = *tmp;
 
 568
 569	io_ctl_map_page(io_ctl, 0);
 570	crc = crc32c(crc, io_ctl->orig + offset, PAGE_SIZE - offset);
 571	btrfs_crc32c_final(crc, (u8 *)&crc);
 
 572	if (val != crc) {
 573		btrfs_err_rl(io_ctl->fs_info,
 574			"csum mismatch on free space cache");
 575		io_ctl_unmap_page(io_ctl);
 576		return -EIO;
 577	}
 578
 579	return 0;
 580}
 581
 582static int io_ctl_add_entry(struct btrfs_io_ctl *io_ctl, u64 offset, u64 bytes,
 583			    void *bitmap)
 584{
 585	struct btrfs_free_space_entry *entry;
 586
 587	if (!io_ctl->cur)
 588		return -ENOSPC;
 589
 590	entry = io_ctl->cur;
 591	put_unaligned_le64(offset, &entry->offset);
 592	put_unaligned_le64(bytes, &entry->bytes);
 593	entry->type = (bitmap) ? BTRFS_FREE_SPACE_BITMAP :
 594		BTRFS_FREE_SPACE_EXTENT;
 595	io_ctl->cur += sizeof(struct btrfs_free_space_entry);
 596	io_ctl->size -= sizeof(struct btrfs_free_space_entry);
 597
 598	if (io_ctl->size >= sizeof(struct btrfs_free_space_entry))
 599		return 0;
 600
 601	io_ctl_set_crc(io_ctl, io_ctl->index - 1);
 602
 603	/* No more pages to map */
 604	if (io_ctl->index >= io_ctl->num_pages)
 605		return 0;
 606
 607	/* map the next page */
 608	io_ctl_map_page(io_ctl, 1);
 609	return 0;
 610}
 611
 612static int io_ctl_add_bitmap(struct btrfs_io_ctl *io_ctl, void *bitmap)
 613{
 614	if (!io_ctl->cur)
 615		return -ENOSPC;
 616
 617	/*
 618	 * If we aren't at the start of the current page, unmap this one and
 619	 * map the next one if there is any left.
 620	 */
 621	if (io_ctl->cur != io_ctl->orig) {
 622		io_ctl_set_crc(io_ctl, io_ctl->index - 1);
 623		if (io_ctl->index >= io_ctl->num_pages)
 624			return -ENOSPC;
 625		io_ctl_map_page(io_ctl, 0);
 626	}
 627
 628	copy_page(io_ctl->cur, bitmap);
 629	io_ctl_set_crc(io_ctl, io_ctl->index - 1);
 630	if (io_ctl->index < io_ctl->num_pages)
 631		io_ctl_map_page(io_ctl, 0);
 632	return 0;
 633}
 634
 635static void io_ctl_zero_remaining_pages(struct btrfs_io_ctl *io_ctl)
 636{
 637	/*
 638	 * If we're not on the boundary we know we've modified the page and we
 639	 * need to crc the page.
 640	 */
 641	if (io_ctl->cur != io_ctl->orig)
 642		io_ctl_set_crc(io_ctl, io_ctl->index - 1);
 643	else
 644		io_ctl_unmap_page(io_ctl);
 645
 646	while (io_ctl->index < io_ctl->num_pages) {
 647		io_ctl_map_page(io_ctl, 1);
 648		io_ctl_set_crc(io_ctl, io_ctl->index - 1);
 649	}
 650}
 651
 652static int io_ctl_read_entry(struct btrfs_io_ctl *io_ctl,
 653			    struct btrfs_free_space *entry, u8 *type)
 654{
 655	struct btrfs_free_space_entry *e;
 656	int ret;
 657
 658	if (!io_ctl->cur) {
 659		ret = io_ctl_check_crc(io_ctl, io_ctl->index);
 660		if (ret)
 661			return ret;
 662	}
 663
 664	e = io_ctl->cur;
 665	entry->offset = get_unaligned_le64(&e->offset);
 666	entry->bytes = get_unaligned_le64(&e->bytes);
 667	*type = e->type;
 668	io_ctl->cur += sizeof(struct btrfs_free_space_entry);
 669	io_ctl->size -= sizeof(struct btrfs_free_space_entry);
 670
 671	if (io_ctl->size >= sizeof(struct btrfs_free_space_entry))
 672		return 0;
 673
 674	io_ctl_unmap_page(io_ctl);
 675
 676	return 0;
 677}
 678
 679static int io_ctl_read_bitmap(struct btrfs_io_ctl *io_ctl,
 680			      struct btrfs_free_space *entry)
 681{
 682	int ret;
 683
 684	ret = io_ctl_check_crc(io_ctl, io_ctl->index);
 685	if (ret)
 686		return ret;
 687
 688	copy_page(entry->bitmap, io_ctl->cur);
 689	io_ctl_unmap_page(io_ctl);
 690
 691	return 0;
 692}
 693
 694static void recalculate_thresholds(struct btrfs_free_space_ctl *ctl)
 
 
 
 
 
 
 
 
 
 695{
 696	struct btrfs_block_group *block_group = ctl->block_group;
 697	u64 max_bytes;
 698	u64 bitmap_bytes;
 699	u64 extent_bytes;
 700	u64 size = block_group->length;
 701	u64 bytes_per_bg = BITS_PER_BITMAP * ctl->unit;
 702	u64 max_bitmaps = div64_u64(size + bytes_per_bg - 1, bytes_per_bg);
 703
 704	max_bitmaps = max_t(u64, max_bitmaps, 1);
 705
 706	if (ctl->total_bitmaps > max_bitmaps)
 707		btrfs_err(block_group->fs_info,
 708"invalid free space control: bg start=%llu len=%llu total_bitmaps=%u unit=%u max_bitmaps=%llu bytes_per_bg=%llu",
 709			  block_group->start, block_group->length,
 710			  ctl->total_bitmaps, ctl->unit, max_bitmaps,
 711			  bytes_per_bg);
 712	ASSERT(ctl->total_bitmaps <= max_bitmaps);
 713
 714	/*
 715	 * We are trying to keep the total amount of memory used per 1GiB of
 716	 * space to be MAX_CACHE_BYTES_PER_GIG.  However, with a reclamation
 717	 * mechanism of pulling extents >= FORCE_EXTENT_THRESHOLD out of
 718	 * bitmaps, we may end up using more memory than this.
 719	 */
 720	if (size < SZ_1G)
 721		max_bytes = MAX_CACHE_BYTES_PER_GIG;
 722	else
 723		max_bytes = MAX_CACHE_BYTES_PER_GIG * div_u64(size, SZ_1G);
 724
 725	bitmap_bytes = ctl->total_bitmaps * ctl->unit;
 726
 727	/*
 728	 * we want the extent entry threshold to always be at most 1/2 the max
 729	 * bytes we can have, or whatever is less than that.
 730	 */
 731	extent_bytes = max_bytes - bitmap_bytes;
 732	extent_bytes = min_t(u64, extent_bytes, max_bytes >> 1);
 733
 734	ctl->extents_thresh =
 735		div_u64(extent_bytes, sizeof(struct btrfs_free_space));
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 736}
 737
 738static int __load_free_space_cache(struct btrfs_root *root, struct inode *inode,
 739				   struct btrfs_free_space_ctl *ctl,
 740				   struct btrfs_path *path, u64 offset)
 741{
 742	struct btrfs_fs_info *fs_info = root->fs_info;
 743	struct btrfs_free_space_header *header;
 744	struct extent_buffer *leaf;
 745	struct btrfs_io_ctl io_ctl;
 746	struct btrfs_key key;
 747	struct btrfs_free_space *e, *n;
 748	LIST_HEAD(bitmaps);
 749	u64 num_entries;
 750	u64 num_bitmaps;
 751	u64 generation;
 752	u8 type;
 753	int ret = 0;
 754
 
 
 755	/* Nothing in the space cache, goodbye */
 756	if (!i_size_read(inode))
 757		return 0;
 758
 759	key.objectid = BTRFS_FREE_SPACE_OBJECTID;
 760	key.offset = offset;
 761	key.type = 0;
 762
 763	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
 764	if (ret < 0)
 765		return 0;
 766	else if (ret > 0) {
 767		btrfs_release_path(path);
 768		return 0;
 769	}
 770
 771	ret = -1;
 772
 773	leaf = path->nodes[0];
 774	header = btrfs_item_ptr(leaf, path->slots[0],
 775				struct btrfs_free_space_header);
 776	num_entries = btrfs_free_space_entries(leaf, header);
 777	num_bitmaps = btrfs_free_space_bitmaps(leaf, header);
 778	generation = btrfs_free_space_generation(leaf, header);
 779	btrfs_release_path(path);
 780
 781	if (!BTRFS_I(inode)->generation) {
 782		btrfs_info(fs_info,
 783			   "the free space cache file (%llu) is invalid, skip it",
 784			   offset);
 785		return 0;
 786	}
 787
 788	if (BTRFS_I(inode)->generation != generation) {
 789		btrfs_err(fs_info,
 790			  "free space inode generation (%llu) did not match free space cache generation (%llu)",
 791			  BTRFS_I(inode)->generation, generation);
 
 792		return 0;
 793	}
 794
 795	if (!num_entries)
 796		return 0;
 797
 798	ret = io_ctl_init(&io_ctl, inode, 0);
 799	if (ret)
 800		return ret;
 801
 802	readahead_cache(inode);
 
 
 803
 804	ret = io_ctl_prepare_pages(&io_ctl, true);
 805	if (ret)
 806		goto out;
 807
 808	ret = io_ctl_check_crc(&io_ctl, 0);
 809	if (ret)
 810		goto free_cache;
 811
 812	ret = io_ctl_check_generation(&io_ctl, generation);
 813	if (ret)
 814		goto free_cache;
 815
 816	while (num_entries) {
 817		e = kmem_cache_zalloc(btrfs_free_space_cachep,
 818				      GFP_NOFS);
 819		if (!e) {
 820			ret = -ENOMEM;
 821			goto free_cache;
 822		}
 823
 824		ret = io_ctl_read_entry(&io_ctl, e, &type);
 825		if (ret) {
 826			kmem_cache_free(btrfs_free_space_cachep, e);
 827			goto free_cache;
 828		}
 829
 830		if (!e->bytes) {
 831			ret = -1;
 832			kmem_cache_free(btrfs_free_space_cachep, e);
 833			goto free_cache;
 834		}
 835
 836		if (type == BTRFS_FREE_SPACE_EXTENT) {
 837			spin_lock(&ctl->tree_lock);
 838			ret = link_free_space(ctl, e);
 839			spin_unlock(&ctl->tree_lock);
 840			if (ret) {
 841				btrfs_err(fs_info,
 842					"Duplicate entries in free space cache, dumping");
 843				kmem_cache_free(btrfs_free_space_cachep, e);
 844				goto free_cache;
 845			}
 846		} else {
 847			ASSERT(num_bitmaps);
 848			num_bitmaps--;
 849			e->bitmap = kmem_cache_zalloc(
 850					btrfs_free_space_bitmap_cachep, GFP_NOFS);
 851			if (!e->bitmap) {
 852				ret = -ENOMEM;
 853				kmem_cache_free(
 854					btrfs_free_space_cachep, e);
 855				goto free_cache;
 856			}
 857			spin_lock(&ctl->tree_lock);
 858			ret = link_free_space(ctl, e);
 
 
 
 859			if (ret) {
 860				spin_unlock(&ctl->tree_lock);
 861				btrfs_err(fs_info,
 862					"Duplicate entries in free space cache, dumping");
 863				kmem_cache_free(btrfs_free_space_cachep, e);
 864				goto free_cache;
 865			}
 866			ctl->total_bitmaps++;
 867			recalculate_thresholds(ctl);
 868			spin_unlock(&ctl->tree_lock);
 869			list_add_tail(&e->list, &bitmaps);
 870		}
 871
 872		num_entries--;
 873	}
 874
 875	io_ctl_unmap_page(&io_ctl);
 876
 877	/*
 878	 * We add the bitmaps at the end of the entries in order that
 879	 * the bitmap entries are added to the cache.
 880	 */
 881	list_for_each_entry_safe(e, n, &bitmaps, list) {
 882		list_del_init(&e->list);
 883		ret = io_ctl_read_bitmap(&io_ctl, e);
 884		if (ret)
 885			goto free_cache;
 886	}
 887
 888	io_ctl_drop_pages(&io_ctl);
 
 889	ret = 1;
 890out:
 891	io_ctl_free(&io_ctl);
 892	return ret;
 893free_cache:
 894	io_ctl_drop_pages(&io_ctl);
 895
 896	spin_lock(&ctl->tree_lock);
 897	__btrfs_remove_free_space_cache(ctl);
 898	spin_unlock(&ctl->tree_lock);
 899	goto out;
 900}
 901
 902static int copy_free_space_cache(struct btrfs_block_group *block_group,
 903				 struct btrfs_free_space_ctl *ctl)
 904{
 905	struct btrfs_free_space *info;
 906	struct rb_node *n;
 907	int ret = 0;
 908
 909	while (!ret && (n = rb_first(&ctl->free_space_offset)) != NULL) {
 910		info = rb_entry(n, struct btrfs_free_space, offset_index);
 911		if (!info->bitmap) {
 912			const u64 offset = info->offset;
 913			const u64 bytes = info->bytes;
 914
 915			unlink_free_space(ctl, info, true);
 916			spin_unlock(&ctl->tree_lock);
 917			kmem_cache_free(btrfs_free_space_cachep, info);
 918			ret = btrfs_add_free_space(block_group, offset, bytes);
 919			spin_lock(&ctl->tree_lock);
 920		} else {
 921			u64 offset = info->offset;
 922			u64 bytes = ctl->unit;
 923
 924			ret = search_bitmap(ctl, info, &offset, &bytes, false);
 925			if (ret == 0) {
 926				bitmap_clear_bits(ctl, info, offset, bytes, true);
 927				spin_unlock(&ctl->tree_lock);
 928				ret = btrfs_add_free_space(block_group, offset,
 929							   bytes);
 930				spin_lock(&ctl->tree_lock);
 931			} else {
 932				free_bitmap(ctl, info);
 933				ret = 0;
 934			}
 935		}
 936		cond_resched_lock(&ctl->tree_lock);
 937	}
 938	return ret;
 939}
 940
 941static struct lock_class_key btrfs_free_space_inode_key;
 942
 943int load_free_space_cache(struct btrfs_block_group *block_group)
 944{
 945	struct btrfs_fs_info *fs_info = block_group->fs_info;
 946	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
 947	struct btrfs_free_space_ctl tmp_ctl = {};
 948	struct inode *inode;
 949	struct btrfs_path *path;
 950	int ret = 0;
 951	bool matched;
 952	u64 used = block_group->used;
 953
 954	/*
 955	 * Because we could potentially discard our loaded free space, we want
 956	 * to load everything into a temporary structure first, and then if it's
 957	 * valid copy it all into the actual free space ctl.
 958	 */
 959	btrfs_init_free_space_ctl(block_group, &tmp_ctl);
 960
 961	/*
 962	 * If this block group has been marked to be cleared for one reason or
 963	 * another then we can't trust the on disk cache, so just return.
 964	 */
 965	spin_lock(&block_group->lock);
 966	if (block_group->disk_cache_state != BTRFS_DC_WRITTEN) {
 967		spin_unlock(&block_group->lock);
 968		return 0;
 969	}
 970	spin_unlock(&block_group->lock);
 971
 972	path = btrfs_alloc_path();
 973	if (!path)
 974		return 0;
 975	path->search_commit_root = 1;
 976	path->skip_locking = 1;
 977
 978	/*
 979	 * We must pass a path with search_commit_root set to btrfs_iget in
 980	 * order to avoid a deadlock when allocating extents for the tree root.
 981	 *
 982	 * When we are COWing an extent buffer from the tree root, when looking
 983	 * for a free extent, at extent-tree.c:find_free_extent(), we can find
 984	 * block group without its free space cache loaded. When we find one
 985	 * we must load its space cache which requires reading its free space
 986	 * cache's inode item from the root tree. If this inode item is located
 987	 * in the same leaf that we started COWing before, then we end up in
 988	 * deadlock on the extent buffer (trying to read lock it when we
 989	 * previously write locked it).
 990	 *
 991	 * It's safe to read the inode item using the commit root because
 992	 * block groups, once loaded, stay in memory forever (until they are
 993	 * removed) as well as their space caches once loaded. New block groups
 994	 * once created get their ->cached field set to BTRFS_CACHE_FINISHED so
 995	 * we will never try to read their inode item while the fs is mounted.
 996	 */
 997	inode = lookup_free_space_inode(block_group, path);
 998	if (IS_ERR(inode)) {
 999		btrfs_free_path(path);
1000		return 0;
1001	}
1002
1003	/* We may have converted the inode and made the cache invalid. */
1004	spin_lock(&block_group->lock);
1005	if (block_group->disk_cache_state != BTRFS_DC_WRITTEN) {
1006		spin_unlock(&block_group->lock);
1007		btrfs_free_path(path);
1008		goto out;
1009	}
1010	spin_unlock(&block_group->lock);
1011
1012	/*
1013	 * Reinitialize the class of struct inode's mapping->invalidate_lock for
1014	 * free space inodes to prevent false positives related to locks for normal
1015	 * inodes.
1016	 */
1017	lockdep_set_class(&(&inode->i_data)->invalidate_lock,
1018			  &btrfs_free_space_inode_key);
1019
1020	ret = __load_free_space_cache(fs_info->tree_root, inode, &tmp_ctl,
1021				      path, block_group->start);
1022	btrfs_free_path(path);
1023	if (ret <= 0)
1024		goto out;
1025
1026	matched = (tmp_ctl.free_space == (block_group->length - used -
1027					  block_group->bytes_super));
 
 
1028
1029	if (matched) {
1030		spin_lock(&tmp_ctl.tree_lock);
1031		ret = copy_free_space_cache(block_group, &tmp_ctl);
1032		spin_unlock(&tmp_ctl.tree_lock);
1033		/*
1034		 * ret == 1 means we successfully loaded the free space cache,
1035		 * so we need to re-set it here.
1036		 */
1037		if (ret == 0)
1038			ret = 1;
1039	} else {
1040		/*
1041		 * We need to call the _locked variant so we don't try to update
1042		 * the discard counters.
1043		 */
1044		spin_lock(&tmp_ctl.tree_lock);
1045		__btrfs_remove_free_space_cache(&tmp_ctl);
1046		spin_unlock(&tmp_ctl.tree_lock);
1047		btrfs_warn(fs_info,
1048			   "block group %llu has wrong amount of free space",
1049			   block_group->start);
1050		ret = -1;
1051	}
1052out:
1053	if (ret < 0) {
1054		/* This cache is bogus, make sure it gets cleared */
1055		spin_lock(&block_group->lock);
1056		block_group->disk_cache_state = BTRFS_DC_CLEAR;
1057		spin_unlock(&block_group->lock);
1058		ret = 0;
1059
1060		btrfs_warn(fs_info,
1061			   "failed to load free space cache for block group %llu, rebuilding it now",
1062			   block_group->start);
1063	}
1064
1065	spin_lock(&ctl->tree_lock);
1066	btrfs_discard_update_discardable(block_group);
1067	spin_unlock(&ctl->tree_lock);
1068	iput(inode);
1069	return ret;
1070}
1071
1072static noinline_for_stack
1073int write_cache_extent_entries(struct btrfs_io_ctl *io_ctl,
1074			      struct btrfs_free_space_ctl *ctl,
1075			      struct btrfs_block_group *block_group,
1076			      int *entries, int *bitmaps,
1077			      struct list_head *bitmap_list)
 
 
 
 
 
 
 
 
 
 
 
 
1078{
1079	int ret;
 
 
 
 
1080	struct btrfs_free_cluster *cluster = NULL;
1081	struct btrfs_free_cluster *cluster_locked = NULL;
1082	struct rb_node *node = rb_first(&ctl->free_space_offset);
1083	struct btrfs_trim_range *trim_entry;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1084
1085	/* Get the cluster for this block_group if it exists */
1086	if (block_group && !list_empty(&block_group->cluster_list)) {
1087		cluster = list_entry(block_group->cluster_list.next,
1088				     struct btrfs_free_cluster,
1089				     block_group_list);
1090	}
1091
 
 
 
 
 
 
 
1092	if (!node && cluster) {
1093		cluster_locked = cluster;
1094		spin_lock(&cluster_locked->lock);
1095		node = rb_first(&cluster->root);
1096		cluster = NULL;
1097	}
1098
 
 
 
 
 
 
 
 
 
1099	/* Write out the extent entries */
1100	while (node) {
1101		struct btrfs_free_space *e;
1102
1103		e = rb_entry(node, struct btrfs_free_space, offset_index);
1104		*entries += 1;
1105
1106		ret = io_ctl_add_entry(io_ctl, e->offset, e->bytes,
1107				       e->bitmap);
1108		if (ret)
1109			goto fail;
1110
1111		if (e->bitmap) {
1112			list_add_tail(&e->list, bitmap_list);
1113			*bitmaps += 1;
1114		}
1115		node = rb_next(node);
1116		if (!node && cluster) {
1117			node = rb_first(&cluster->root);
1118			cluster_locked = cluster;
1119			spin_lock(&cluster_locked->lock);
1120			cluster = NULL;
1121		}
1122	}
1123	if (cluster_locked) {
1124		spin_unlock(&cluster_locked->lock);
1125		cluster_locked = NULL;
1126	}
1127
1128	/*
1129	 * Make sure we don't miss any range that was removed from our rbtree
1130	 * because trimming is running. Otherwise after a umount+mount (or crash
1131	 * after committing the transaction) we would leak free space and get
1132	 * an inconsistent free space cache report from fsck.
1133	 */
1134	list_for_each_entry(trim_entry, &ctl->trimming_ranges, list) {
1135		ret = io_ctl_add_entry(io_ctl, trim_entry->start,
1136				       trim_entry->bytes, NULL);
1137		if (ret)
1138			goto fail;
1139		*entries += 1;
1140	}
1141
1142	return 0;
1143fail:
1144	if (cluster_locked)
1145		spin_unlock(&cluster_locked->lock);
1146	return -ENOSPC;
1147}
1148
1149static noinline_for_stack int
1150update_cache_item(struct btrfs_trans_handle *trans,
1151		  struct btrfs_root *root,
1152		  struct inode *inode,
1153		  struct btrfs_path *path, u64 offset,
1154		  int entries, int bitmaps)
1155{
1156	struct btrfs_key key;
1157	struct btrfs_free_space_header *header;
1158	struct extent_buffer *leaf;
1159	int ret;
1160
1161	key.objectid = BTRFS_FREE_SPACE_OBJECTID;
1162	key.offset = offset;
1163	key.type = 0;
1164
1165	ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
1166	if (ret < 0) {
1167		clear_extent_bit(&BTRFS_I(inode)->io_tree, 0, inode->i_size - 1,
1168				 EXTENT_DELALLOC, NULL);
1169		goto fail;
1170	}
1171	leaf = path->nodes[0];
1172	if (ret > 0) {
1173		struct btrfs_key found_key;
1174		ASSERT(path->slots[0]);
1175		path->slots[0]--;
1176		btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
1177		if (found_key.objectid != BTRFS_FREE_SPACE_OBJECTID ||
1178		    found_key.offset != offset) {
1179			clear_extent_bit(&BTRFS_I(inode)->io_tree, 0,
1180					 inode->i_size - 1, EXTENT_DELALLOC,
1181					 NULL);
1182			btrfs_release_path(path);
1183			goto fail;
1184		}
1185	}
1186
1187	BTRFS_I(inode)->generation = trans->transid;
1188	header = btrfs_item_ptr(leaf, path->slots[0],
1189				struct btrfs_free_space_header);
1190	btrfs_set_free_space_entries(leaf, header, entries);
1191	btrfs_set_free_space_bitmaps(leaf, header, bitmaps);
1192	btrfs_set_free_space_generation(leaf, header, trans->transid);
1193	btrfs_mark_buffer_dirty(trans, leaf);
1194	btrfs_release_path(path);
1195
1196	return 0;
1197
1198fail:
1199	return -1;
1200}
1201
1202static noinline_for_stack int write_pinned_extent_entries(
1203			    struct btrfs_trans_handle *trans,
1204			    struct btrfs_block_group *block_group,
1205			    struct btrfs_io_ctl *io_ctl,
1206			    int *entries)
1207{
1208	u64 start, extent_start, extent_end, len;
1209	struct extent_io_tree *unpin = NULL;
1210	int ret;
1211
1212	if (!block_group)
1213		return 0;
1214
1215	/*
1216	 * We want to add any pinned extents to our free space cache
1217	 * so we don't leak the space
1218	 *
1219	 * We shouldn't have switched the pinned extents yet so this is the
1220	 * right one
1221	 */
1222	unpin = &trans->transaction->pinned_extents;
1223
1224	start = block_group->start;
 
1225
1226	while (start < block_group->start + block_group->length) {
1227		if (!find_first_extent_bit(unpin, start,
1228					   &extent_start, &extent_end,
1229					   EXTENT_DIRTY, NULL))
1230			return 0;
 
 
 
 
1231
1232		/* This pinned extent is out of our range */
1233		if (extent_start >= block_group->start + block_group->length)
1234			return 0;
 
1235
1236		extent_start = max(extent_start, start);
1237		extent_end = min(block_group->start + block_group->length,
1238				 extent_end + 1);
1239		len = extent_end - extent_start;
1240
1241		*entries += 1;
1242		ret = io_ctl_add_entry(io_ctl, extent_start, len, NULL);
1243		if (ret)
1244			return -ENOSPC;
1245
1246		start = extent_end;
1247	}
1248
1249	return 0;
1250}
1251
1252static noinline_for_stack int
1253write_bitmap_entries(struct btrfs_io_ctl *io_ctl, struct list_head *bitmap_list)
1254{
1255	struct btrfs_free_space *entry, *next;
1256	int ret;
1257
1258	/* Write out the bitmaps */
1259	list_for_each_entry_safe(entry, next, bitmap_list, list) {
1260		ret = io_ctl_add_bitmap(io_ctl, entry->bitmap);
 
 
 
1261		if (ret)
1262			return -ENOSPC;
1263		list_del_init(&entry->list);
1264	}
1265
1266	return 0;
1267}
1268
1269static int flush_dirty_cache(struct inode *inode)
1270{
1271	int ret;
1272
1273	ret = btrfs_wait_ordered_range(inode, 0, (u64)-1);
1274	if (ret)
1275		clear_extent_bit(&BTRFS_I(inode)->io_tree, 0, inode->i_size - 1,
1276				 EXTENT_DELALLOC, NULL);
1277
1278	return ret;
1279}
1280
1281static void noinline_for_stack
1282cleanup_bitmap_list(struct list_head *bitmap_list)
1283{
1284	struct btrfs_free_space *entry, *next;
1285
1286	list_for_each_entry_safe(entry, next, bitmap_list, list)
1287		list_del_init(&entry->list);
1288}
1289
1290static void noinline_for_stack
1291cleanup_write_cache_enospc(struct inode *inode,
1292			   struct btrfs_io_ctl *io_ctl,
1293			   struct extent_state **cached_state)
1294{
1295	io_ctl_drop_pages(io_ctl);
1296	unlock_extent(&BTRFS_I(inode)->io_tree, 0, i_size_read(inode) - 1,
1297		      cached_state);
1298}
1299
1300static int __btrfs_wait_cache_io(struct btrfs_root *root,
1301				 struct btrfs_trans_handle *trans,
1302				 struct btrfs_block_group *block_group,
1303				 struct btrfs_io_ctl *io_ctl,
1304				 struct btrfs_path *path, u64 offset)
1305{
1306	int ret;
1307	struct inode *inode = io_ctl->inode;
1308
1309	if (!inode)
1310		return 0;
 
 
 
1311
1312	/* Flush the dirty pages in the cache file. */
1313	ret = flush_dirty_cache(inode);
1314	if (ret)
1315		goto out;
1316
1317	/* Update the cache item to tell everyone this cache file is valid. */
1318	ret = update_cache_item(trans, root, inode, path, offset,
1319				io_ctl->entries, io_ctl->bitmaps);
1320out:
1321	if (ret) {
1322		invalidate_inode_pages2(inode->i_mapping);
1323		BTRFS_I(inode)->generation = 0;
1324		if (block_group)
1325			btrfs_debug(root->fs_info,
1326	  "failed to write free space cache for block group %llu error %d",
1327				  block_group->start, ret);
1328	}
1329	btrfs_update_inode(trans, BTRFS_I(inode));
1330
1331	if (block_group) {
1332		/* the dirty list is protected by the dirty_bgs_lock */
1333		spin_lock(&trans->transaction->dirty_bgs_lock);
1334
1335		/* the disk_cache_state is protected by the block group lock */
1336		spin_lock(&block_group->lock);
1337
1338		/*
1339		 * only mark this as written if we didn't get put back on
1340		 * the dirty list while waiting for IO.   Otherwise our
1341		 * cache state won't be right, and we won't get written again
1342		 */
1343		if (!ret && list_empty(&block_group->dirty_list))
1344			block_group->disk_cache_state = BTRFS_DC_WRITTEN;
1345		else if (ret)
1346			block_group->disk_cache_state = BTRFS_DC_ERROR;
1347
1348		spin_unlock(&block_group->lock);
1349		spin_unlock(&trans->transaction->dirty_bgs_lock);
1350		io_ctl->inode = NULL;
1351		iput(inode);
 
 
1352	}
1353
1354	return ret;
1355
1356}
1357
1358int btrfs_wait_cache_io(struct btrfs_trans_handle *trans,
1359			struct btrfs_block_group *block_group,
1360			struct btrfs_path *path)
1361{
1362	return __btrfs_wait_cache_io(block_group->fs_info->tree_root, trans,
1363				     block_group, &block_group->io_ctl,
1364				     path, block_group->start);
1365}
1366
1367/*
1368 * Write out cached info to an inode.
1369 *
1370 * @inode:       freespace inode we are writing out
1371 * @ctl:         free space cache we are going to write out
1372 * @block_group: block_group for this cache if it belongs to a block_group
1373 * @io_ctl:      holds context for the io
1374 * @trans:       the trans handle
1375 *
1376 * This function writes out a free space cache struct to disk for quick recovery
1377 * on mount.  This will return 0 if it was successful in writing the cache out,
1378 * or an errno if it was not.
1379 */
1380static int __btrfs_write_out_cache(struct inode *inode,
1381				   struct btrfs_free_space_ctl *ctl,
1382				   struct btrfs_block_group *block_group,
1383				   struct btrfs_io_ctl *io_ctl,
1384				   struct btrfs_trans_handle *trans)
1385{
1386	struct extent_state *cached_state = NULL;
1387	LIST_HEAD(bitmap_list);
1388	int entries = 0;
1389	int bitmaps = 0;
1390	int ret;
1391	int must_iput = 0;
1392
1393	if (!i_size_read(inode))
1394		return -EIO;
1395
1396	WARN_ON(io_ctl->pages);
1397	ret = io_ctl_init(io_ctl, inode, 1);
1398	if (ret)
1399		return ret;
1400
1401	if (block_group && (block_group->flags & BTRFS_BLOCK_GROUP_DATA)) {
1402		down_write(&block_group->data_rwsem);
1403		spin_lock(&block_group->lock);
1404		if (block_group->delalloc_bytes) {
1405			block_group->disk_cache_state = BTRFS_DC_WRITTEN;
1406			spin_unlock(&block_group->lock);
1407			up_write(&block_group->data_rwsem);
1408			BTRFS_I(inode)->generation = 0;
1409			ret = 0;
1410			must_iput = 1;
1411			goto out;
1412		}
1413		spin_unlock(&block_group->lock);
1414	}
1415
1416	/* Lock all pages first so we can lock the extent safely. */
1417	ret = io_ctl_prepare_pages(io_ctl, false);
1418	if (ret)
1419		goto out_unlock;
1420
1421	lock_extent(&BTRFS_I(inode)->io_tree, 0, i_size_read(inode) - 1,
1422		    &cached_state);
1423
1424	io_ctl_set_generation(io_ctl, trans->transid);
1425
1426	mutex_lock(&ctl->cache_writeout_mutex);
1427	/* Write out the extent entries in the free space cache */
1428	spin_lock(&ctl->tree_lock);
1429	ret = write_cache_extent_entries(io_ctl, ctl,
1430					 block_group, &entries, &bitmaps,
1431					 &bitmap_list);
1432	if (ret)
1433		goto out_nospc_locked;
1434
1435	/*
1436	 * Some spaces that are freed in the current transaction are pinned,
1437	 * they will be added into free space cache after the transaction is
1438	 * committed, we shouldn't lose them.
1439	 *
1440	 * If this changes while we are working we'll get added back to
1441	 * the dirty list and redo it.  No locking needed
1442	 */
1443	ret = write_pinned_extent_entries(trans, block_group, io_ctl, &entries);
1444	if (ret)
1445		goto out_nospc_locked;
1446
1447	/*
1448	 * At last, we write out all the bitmaps and keep cache_writeout_mutex
1449	 * locked while doing it because a concurrent trim can be manipulating
1450	 * or freeing the bitmap.
1451	 */
1452	ret = write_bitmap_entries(io_ctl, &bitmap_list);
1453	spin_unlock(&ctl->tree_lock);
1454	mutex_unlock(&ctl->cache_writeout_mutex);
1455	if (ret)
1456		goto out_nospc;
1457
1458	/* Zero out the rest of the pages just to make sure */
1459	io_ctl_zero_remaining_pages(io_ctl);
1460
1461	/* Everything is written out, now we dirty the pages in the file. */
1462	ret = btrfs_dirty_pages(BTRFS_I(inode), io_ctl->pages,
1463				io_ctl->num_pages, 0, i_size_read(inode),
1464				&cached_state, false);
1465	if (ret)
1466		goto out_nospc;
1467
1468	if (block_group && (block_group->flags & BTRFS_BLOCK_GROUP_DATA))
1469		up_write(&block_group->data_rwsem);
1470	/*
1471	 * Release the pages and unlock the extent, we will flush
1472	 * them out later
1473	 */
1474	io_ctl_drop_pages(io_ctl);
1475	io_ctl_free(io_ctl);
1476
1477	unlock_extent(&BTRFS_I(inode)->io_tree, 0, i_size_read(inode) - 1,
1478		      &cached_state);
1479
1480	/*
1481	 * at this point the pages are under IO and we're happy,
1482	 * The caller is responsible for waiting on them and updating
1483	 * the cache and the inode
1484	 */
1485	io_ctl->entries = entries;
1486	io_ctl->bitmaps = bitmaps;
1487
1488	ret = btrfs_fdatawrite_range(inode, 0, (u64)-1);
1489	if (ret)
1490		goto out;
1491
1492	return 0;
1493
1494out_nospc_locked:
1495	cleanup_bitmap_list(&bitmap_list);
1496	spin_unlock(&ctl->tree_lock);
1497	mutex_unlock(&ctl->cache_writeout_mutex);
1498
1499out_nospc:
1500	cleanup_write_cache_enospc(inode, io_ctl, &cached_state);
1501
1502out_unlock:
1503	if (block_group && (block_group->flags & BTRFS_BLOCK_GROUP_DATA))
1504		up_write(&block_group->data_rwsem);
1505
 
1506out:
1507	io_ctl->inode = NULL;
1508	io_ctl_free(io_ctl);
1509	if (ret) {
1510		invalidate_inode_pages2(inode->i_mapping);
1511		BTRFS_I(inode)->generation = 0;
1512	}
1513	btrfs_update_inode(trans, BTRFS_I(inode));
1514	if (must_iput)
1515		iput(inode);
1516	return ret;
 
 
 
 
 
 
 
 
 
1517}
1518
1519int btrfs_write_out_cache(struct btrfs_trans_handle *trans,
1520			  struct btrfs_block_group *block_group,
 
1521			  struct btrfs_path *path)
1522{
1523	struct btrfs_fs_info *fs_info = trans->fs_info;
1524	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
1525	struct inode *inode;
1526	int ret = 0;
1527
 
 
1528	spin_lock(&block_group->lock);
1529	if (block_group->disk_cache_state < BTRFS_DC_SETUP) {
1530		spin_unlock(&block_group->lock);
1531		return 0;
1532	}
1533	spin_unlock(&block_group->lock);
1534
1535	inode = lookup_free_space_inode(block_group, path);
1536	if (IS_ERR(inode))
1537		return 0;
1538
1539	ret = __btrfs_write_out_cache(inode, ctl, block_group,
1540				      &block_group->io_ctl, trans);
1541	if (ret) {
1542		btrfs_debug(fs_info,
1543	  "failed to write free space cache for block group %llu error %d",
1544			  block_group->start, ret);
1545		spin_lock(&block_group->lock);
1546		block_group->disk_cache_state = BTRFS_DC_ERROR;
1547		spin_unlock(&block_group->lock);
1548
1549		block_group->io_ctl.inode = NULL;
1550		iput(inode);
 
 
1551	}
1552
1553	/*
1554	 * if ret == 0 the caller is expected to call btrfs_wait_cache_io
1555	 * to wait for IO and put the inode
1556	 */
1557
1558	return ret;
1559}
1560
1561static inline unsigned long offset_to_bit(u64 bitmap_start, u32 unit,
1562					  u64 offset)
1563{
1564	ASSERT(offset >= bitmap_start);
1565	offset -= bitmap_start;
1566	return (unsigned long)(div_u64(offset, unit));
1567}
1568
1569static inline unsigned long bytes_to_bits(u64 bytes, u32 unit)
1570{
1571	return (unsigned long)(div_u64(bytes, unit));
1572}
1573
1574static inline u64 offset_to_bitmap(struct btrfs_free_space_ctl *ctl,
1575				   u64 offset)
1576{
1577	u64 bitmap_start;
1578	u64 bytes_per_bitmap;
1579
1580	bytes_per_bitmap = BITS_PER_BITMAP * ctl->unit;
1581	bitmap_start = offset - ctl->start;
1582	bitmap_start = div64_u64(bitmap_start, bytes_per_bitmap);
1583	bitmap_start *= bytes_per_bitmap;
1584	bitmap_start += ctl->start;
1585
1586	return bitmap_start;
1587}
1588
1589static int tree_insert_offset(struct btrfs_free_space_ctl *ctl,
1590			      struct btrfs_free_cluster *cluster,
1591			      struct btrfs_free_space *new_entry)
1592{
1593	struct rb_root *root;
1594	struct rb_node **p;
1595	struct rb_node *parent = NULL;
1596
1597	lockdep_assert_held(&ctl->tree_lock);
1598
1599	if (cluster) {
1600		lockdep_assert_held(&cluster->lock);
1601		root = &cluster->root;
1602	} else {
1603		root = &ctl->free_space_offset;
1604	}
1605
1606	p = &root->rb_node;
1607
1608	while (*p) {
1609		struct btrfs_free_space *info;
1610
1611		parent = *p;
1612		info = rb_entry(parent, struct btrfs_free_space, offset_index);
1613
1614		if (new_entry->offset < info->offset) {
1615			p = &(*p)->rb_left;
1616		} else if (new_entry->offset > info->offset) {
1617			p = &(*p)->rb_right;
1618		} else {
1619			/*
1620			 * we could have a bitmap entry and an extent entry
1621			 * share the same offset.  If this is the case, we want
1622			 * the extent entry to always be found first if we do a
1623			 * linear search through the tree, since we want to have
1624			 * the quickest allocation time, and allocating from an
1625			 * extent is faster than allocating from a bitmap.  So
1626			 * if we're inserting a bitmap and we find an entry at
1627			 * this offset, we want to go right, or after this entry
1628			 * logically.  If we are inserting an extent and we've
1629			 * found a bitmap, we want to go left, or before
1630			 * logically.
1631			 */
1632			if (new_entry->bitmap) {
1633				if (info->bitmap) {
1634					WARN_ON_ONCE(1);
1635					return -EEXIST;
1636				}
1637				p = &(*p)->rb_right;
1638			} else {
1639				if (!info->bitmap) {
1640					WARN_ON_ONCE(1);
1641					return -EEXIST;
1642				}
1643				p = &(*p)->rb_left;
1644			}
1645		}
1646	}
1647
1648	rb_link_node(&new_entry->offset_index, parent, p);
1649	rb_insert_color(&new_entry->offset_index, root);
1650
1651	return 0;
1652}
1653
1654/*
1655 * This is a little subtle.  We *only* have ->max_extent_size set if we actually
1656 * searched through the bitmap and figured out the largest ->max_extent_size,
1657 * otherwise it's 0.  In the case that it's 0 we don't want to tell the
1658 * allocator the wrong thing, we want to use the actual real max_extent_size
1659 * we've found already if it's larger, or we want to use ->bytes.
1660 *
1661 * This matters because find_free_space() will skip entries who's ->bytes is
1662 * less than the required bytes.  So if we didn't search down this bitmap, we
1663 * may pick some previous entry that has a smaller ->max_extent_size than we
1664 * have.  For example, assume we have two entries, one that has
1665 * ->max_extent_size set to 4K and ->bytes set to 1M.  A second entry hasn't set
1666 * ->max_extent_size yet, has ->bytes set to 8K and it's contiguous.  We will
1667 *  call into find_free_space(), and return with max_extent_size == 4K, because
1668 *  that first bitmap entry had ->max_extent_size set, but the second one did
1669 *  not.  If instead we returned 8K we'd come in searching for 8K, and find the
1670 *  8K contiguous range.
1671 *
1672 *  Consider the other case, we have 2 8K chunks in that second entry and still
1673 *  don't have ->max_extent_size set.  We'll return 16K, and the next time the
1674 *  allocator comes in it'll fully search our second bitmap, and this time it'll
1675 *  get an uptodate value of 8K as the maximum chunk size.  Then we'll get the
1676 *  right allocation the next loop through.
1677 */
1678static inline u64 get_max_extent_size(const struct btrfs_free_space *entry)
1679{
1680	if (entry->bitmap && entry->max_extent_size)
1681		return entry->max_extent_size;
1682	return entry->bytes;
1683}
1684
1685/*
1686 * We want the largest entry to be leftmost, so this is inverted from what you'd
1687 * normally expect.
1688 */
1689static bool entry_less(struct rb_node *node, const struct rb_node *parent)
1690{
1691	const struct btrfs_free_space *entry, *exist;
1692
1693	entry = rb_entry(node, struct btrfs_free_space, bytes_index);
1694	exist = rb_entry(parent, struct btrfs_free_space, bytes_index);
1695	return get_max_extent_size(exist) < get_max_extent_size(entry);
1696}
1697
1698/*
1699 * searches the tree for the given offset.
1700 *
1701 * fuzzy - If this is set, then we are trying to make an allocation, and we just
1702 * want a section that has at least bytes size and comes at or after the given
1703 * offset.
1704 */
1705static struct btrfs_free_space *
1706tree_search_offset(struct btrfs_free_space_ctl *ctl,
1707		   u64 offset, int bitmap_only, int fuzzy)
1708{
1709	struct rb_node *n = ctl->free_space_offset.rb_node;
1710	struct btrfs_free_space *entry = NULL, *prev = NULL;
1711
1712	lockdep_assert_held(&ctl->tree_lock);
1713
1714	/* find entry that is closest to the 'offset' */
1715	while (n) {
 
 
 
 
 
1716		entry = rb_entry(n, struct btrfs_free_space, offset_index);
1717		prev = entry;
1718
1719		if (offset < entry->offset)
1720			n = n->rb_left;
1721		else if (offset > entry->offset)
1722			n = n->rb_right;
1723		else
1724			break;
1725
1726		entry = NULL;
1727	}
1728
1729	if (bitmap_only) {
1730		if (!entry)
1731			return NULL;
1732		if (entry->bitmap)
1733			return entry;
1734
1735		/*
1736		 * bitmap entry and extent entry may share same offset,
1737		 * in that case, bitmap entry comes after extent entry.
1738		 */
1739		n = rb_next(n);
1740		if (!n)
1741			return NULL;
1742		entry = rb_entry(n, struct btrfs_free_space, offset_index);
1743		if (entry->offset != offset)
1744			return NULL;
1745
1746		WARN_ON(!entry->bitmap);
1747		return entry;
1748	} else if (entry) {
1749		if (entry->bitmap) {
1750			/*
1751			 * if previous extent entry covers the offset,
1752			 * we should return it instead of the bitmap entry
1753			 */
1754			n = rb_prev(&entry->offset_index);
1755			if (n) {
 
 
 
1756				prev = rb_entry(n, struct btrfs_free_space,
1757						offset_index);
1758				if (!prev->bitmap &&
1759				    prev->offset + prev->bytes > offset)
1760					entry = prev;
 
 
1761			}
1762		}
1763		return entry;
1764	}
1765
1766	if (!prev)
1767		return NULL;
1768
1769	/* find last entry before the 'offset' */
1770	entry = prev;
1771	if (entry->offset > offset) {
1772		n = rb_prev(&entry->offset_index);
1773		if (n) {
1774			entry = rb_entry(n, struct btrfs_free_space,
1775					offset_index);
1776			ASSERT(entry->offset <= offset);
1777		} else {
1778			if (fuzzy)
1779				return entry;
1780			else
1781				return NULL;
1782		}
1783	}
1784
1785	if (entry->bitmap) {
1786		n = rb_prev(&entry->offset_index);
1787		if (n) {
 
 
 
1788			prev = rb_entry(n, struct btrfs_free_space,
1789					offset_index);
1790			if (!prev->bitmap &&
1791			    prev->offset + prev->bytes > offset)
1792				return prev;
 
 
1793		}
1794		if (entry->offset + BITS_PER_BITMAP * ctl->unit > offset)
1795			return entry;
1796	} else if (entry->offset + entry->bytes > offset)
1797		return entry;
1798
1799	if (!fuzzy)
1800		return NULL;
1801
1802	while (1) {
1803		n = rb_next(&entry->offset_index);
1804		if (!n)
1805			return NULL;
1806		entry = rb_entry(n, struct btrfs_free_space, offset_index);
1807		if (entry->bitmap) {
1808			if (entry->offset + BITS_PER_BITMAP *
1809			    ctl->unit > offset)
1810				break;
1811		} else {
1812			if (entry->offset + entry->bytes > offset)
1813				break;
1814		}
 
 
 
 
 
1815	}
1816	return entry;
1817}
1818
1819static inline void unlink_free_space(struct btrfs_free_space_ctl *ctl,
1820				     struct btrfs_free_space *info,
1821				     bool update_stat)
1822{
1823	lockdep_assert_held(&ctl->tree_lock);
1824
1825	rb_erase(&info->offset_index, &ctl->free_space_offset);
1826	rb_erase_cached(&info->bytes_index, &ctl->free_space_bytes);
1827	ctl->free_extents--;
 
1828
1829	if (!info->bitmap && !btrfs_free_space_trimmed(info)) {
1830		ctl->discardable_extents[BTRFS_STAT_CURR]--;
1831		ctl->discardable_bytes[BTRFS_STAT_CURR] -= info->bytes;
1832	}
1833
1834	if (update_stat)
1835		ctl->free_space -= info->bytes;
1836}
1837
1838static int link_free_space(struct btrfs_free_space_ctl *ctl,
1839			   struct btrfs_free_space *info)
1840{
1841	int ret = 0;
1842
1843	lockdep_assert_held(&ctl->tree_lock);
1844
1845	ASSERT(info->bytes || info->bitmap);
1846	ret = tree_insert_offset(ctl, NULL, info);
1847	if (ret)
1848		return ret;
1849
1850	rb_add_cached(&info->bytes_index, &ctl->free_space_bytes, entry_less);
1851
1852	if (!info->bitmap && !btrfs_free_space_trimmed(info)) {
1853		ctl->discardable_extents[BTRFS_STAT_CURR]++;
1854		ctl->discardable_bytes[BTRFS_STAT_CURR] += info->bytes;
1855	}
1856
1857	ctl->free_space += info->bytes;
1858	ctl->free_extents++;
1859	return ret;
1860}
1861
1862static void relink_bitmap_entry(struct btrfs_free_space_ctl *ctl,
1863				struct btrfs_free_space *info)
1864{
1865	ASSERT(info->bitmap);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1866
1867	/*
1868	 * If our entry is empty it's because we're on a cluster and we don't
1869	 * want to re-link it into our ctl bytes index.
 
1870	 */
1871	if (RB_EMPTY_NODE(&info->bytes_index))
 
 
 
1872		return;
 
1873
1874	lockdep_assert_held(&ctl->tree_lock);
 
 
 
 
 
1875
1876	rb_erase_cached(&info->bytes_index, &ctl->free_space_bytes);
1877	rb_add_cached(&info->bytes_index, &ctl->free_space_bytes, entry_less);
1878}
1879
1880static inline void bitmap_clear_bits(struct btrfs_free_space_ctl *ctl,
1881				     struct btrfs_free_space *info,
1882				     u64 offset, u64 bytes, bool update_stat)
1883{
1884	unsigned long start, count, end;
1885	int extent_delta = -1;
1886
1887	start = offset_to_bit(info->offset, ctl->unit, offset);
1888	count = bytes_to_bits(bytes, ctl->unit);
1889	end = start + count;
1890	ASSERT(end <= BITS_PER_BITMAP);
1891
1892	bitmap_clear(info->bitmap, start, count);
1893
1894	info->bytes -= bytes;
1895	if (info->max_extent_size > ctl->unit)
1896		info->max_extent_size = 0;
1897
1898	relink_bitmap_entry(ctl, info);
1899
1900	if (start && test_bit(start - 1, info->bitmap))
1901		extent_delta++;
1902
1903	if (end < BITS_PER_BITMAP && test_bit(end, info->bitmap))
1904		extent_delta++;
1905
1906	info->bitmap_extents += extent_delta;
1907	if (!btrfs_free_space_trimmed(info)) {
1908		ctl->discardable_extents[BTRFS_STAT_CURR] += extent_delta;
1909		ctl->discardable_bytes[BTRFS_STAT_CURR] -= bytes;
1910	}
1911
1912	if (update_stat)
1913		ctl->free_space -= bytes;
 
 
 
 
1914}
1915
1916static void bitmap_set_bits(struct btrfs_free_space_ctl *ctl,
1917			    struct btrfs_free_space *info, u64 offset,
1918			    u64 bytes)
1919{
1920	unsigned long start, count, end;
1921	int extent_delta = 1;
1922
1923	start = offset_to_bit(info->offset, ctl->unit, offset);
1924	count = bytes_to_bits(bytes, ctl->unit);
1925	end = start + count;
1926	ASSERT(end <= BITS_PER_BITMAP);
1927
1928	bitmap_set(info->bitmap, start, count);
1929
1930	/*
1931	 * We set some bytes, we have no idea what the max extent size is
1932	 * anymore.
1933	 */
1934	info->max_extent_size = 0;
1935	info->bytes += bytes;
1936	ctl->free_space += bytes;
1937
1938	relink_bitmap_entry(ctl, info);
1939
1940	if (start && test_bit(start - 1, info->bitmap))
1941		extent_delta--;
1942
1943	if (end < BITS_PER_BITMAP && test_bit(end, info->bitmap))
1944		extent_delta--;
1945
1946	info->bitmap_extents += extent_delta;
1947	if (!btrfs_free_space_trimmed(info)) {
1948		ctl->discardable_extents[BTRFS_STAT_CURR] += extent_delta;
1949		ctl->discardable_bytes[BTRFS_STAT_CURR] += bytes;
1950	}
1951}
1952
1953/*
1954 * If we can not find suitable extent, we will use bytes to record
1955 * the size of the max extent.
1956 */
1957static int search_bitmap(struct btrfs_free_space_ctl *ctl,
1958			 struct btrfs_free_space *bitmap_info, u64 *offset,
1959			 u64 *bytes, bool for_alloc)
1960{
1961	unsigned long found_bits = 0;
1962	unsigned long max_bits = 0;
1963	unsigned long bits, i;
1964	unsigned long next_zero;
1965	unsigned long extent_bits;
1966
1967	/*
1968	 * Skip searching the bitmap if we don't have a contiguous section that
1969	 * is large enough for this allocation.
1970	 */
1971	if (for_alloc &&
1972	    bitmap_info->max_extent_size &&
1973	    bitmap_info->max_extent_size < *bytes) {
1974		*bytes = bitmap_info->max_extent_size;
1975		return -1;
1976	}
1977
1978	i = offset_to_bit(bitmap_info->offset, ctl->unit,
1979			  max_t(u64, *offset, bitmap_info->offset));
1980	bits = bytes_to_bits(*bytes, ctl->unit);
1981
1982	for_each_set_bit_from(i, bitmap_info->bitmap, BITS_PER_BITMAP) {
1983		if (for_alloc && bits == 1) {
1984			found_bits = 1;
1985			break;
1986		}
1987		next_zero = find_next_zero_bit(bitmap_info->bitmap,
1988					       BITS_PER_BITMAP, i);
1989		extent_bits = next_zero - i;
1990		if (extent_bits >= bits) {
1991			found_bits = extent_bits;
1992			break;
1993		} else if (extent_bits > max_bits) {
1994			max_bits = extent_bits;
1995		}
1996		i = next_zero;
1997	}
1998
1999	if (found_bits) {
2000		*offset = (u64)(i * ctl->unit) + bitmap_info->offset;
2001		*bytes = (u64)(found_bits) * ctl->unit;
2002		return 0;
2003	}
2004
2005	*bytes = (u64)(max_bits) * ctl->unit;
2006	bitmap_info->max_extent_size = *bytes;
2007	relink_bitmap_entry(ctl, bitmap_info);
2008	return -1;
2009}
2010
2011/* Cache the size of the max extent in bytes */
2012static struct btrfs_free_space *
2013find_free_space(struct btrfs_free_space_ctl *ctl, u64 *offset, u64 *bytes,
2014		unsigned long align, u64 *max_extent_size, bool use_bytes_index)
2015{
2016	struct btrfs_free_space *entry;
2017	struct rb_node *node;
2018	u64 tmp;
2019	u64 align_off;
2020	int ret;
2021
2022	if (!ctl->free_space_offset.rb_node)
2023		goto out;
2024again:
2025	if (use_bytes_index) {
2026		node = rb_first_cached(&ctl->free_space_bytes);
2027	} else {
2028		entry = tree_search_offset(ctl, offset_to_bitmap(ctl, *offset),
2029					   0, 1);
2030		if (!entry)
2031			goto out;
2032		node = &entry->offset_index;
2033	}
2034
2035	for (; node; node = rb_next(node)) {
2036		if (use_bytes_index)
2037			entry = rb_entry(node, struct btrfs_free_space,
2038					 bytes_index);
2039		else
2040			entry = rb_entry(node, struct btrfs_free_space,
2041					 offset_index);
2042
2043		/*
2044		 * If we are using the bytes index then all subsequent entries
2045		 * in this tree are going to be < bytes, so simply set the max
2046		 * extent size and exit the loop.
2047		 *
2048		 * If we're using the offset index then we need to keep going
2049		 * through the rest of the tree.
2050		 */
2051		if (entry->bytes < *bytes) {
2052			*max_extent_size = max(get_max_extent_size(entry),
2053					       *max_extent_size);
2054			if (use_bytes_index)
2055				break;
2056			continue;
2057		}
2058
2059		/* make sure the space returned is big enough
2060		 * to match our requested alignment
2061		 */
2062		if (*bytes >= align) {
2063			tmp = entry->offset - ctl->start + align - 1;
2064			tmp = div64_u64(tmp, align);
2065			tmp = tmp * align + ctl->start;
2066			align_off = tmp - entry->offset;
2067		} else {
2068			align_off = 0;
2069			tmp = entry->offset;
2070		}
2071
2072		/*
2073		 * We don't break here if we're using the bytes index because we
2074		 * may have another entry that has the correct alignment that is
2075		 * the right size, so we don't want to miss that possibility.
2076		 * At worst this adds another loop through the logic, but if we
2077		 * broke here we could prematurely ENOSPC.
2078		 */
2079		if (entry->bytes < *bytes + align_off) {
2080			*max_extent_size = max(get_max_extent_size(entry),
2081					       *max_extent_size);
2082			continue;
2083		}
2084
2085		if (entry->bitmap) {
2086			struct rb_node *old_next = rb_next(node);
2087			u64 size = *bytes;
2088
2089			ret = search_bitmap(ctl, entry, &tmp, &size, true);
2090			if (!ret) {
2091				*offset = tmp;
2092				*bytes = size;
2093				return entry;
2094			} else {
2095				*max_extent_size =
2096					max(get_max_extent_size(entry),
2097					    *max_extent_size);
2098			}
2099
2100			/*
2101			 * The bitmap may have gotten re-arranged in the space
2102			 * index here because the max_extent_size may have been
2103			 * updated.  Start from the beginning again if this
2104			 * happened.
2105			 */
2106			if (use_bytes_index && old_next != rb_next(node))
2107				goto again;
2108			continue;
2109		}
2110
2111		*offset = tmp;
2112		*bytes = entry->bytes - align_off;
2113		return entry;
2114	}
2115out:
2116	return NULL;
2117}
2118
2119static void add_new_bitmap(struct btrfs_free_space_ctl *ctl,
2120			   struct btrfs_free_space *info, u64 offset)
2121{
2122	info->offset = offset_to_bitmap(ctl, offset);
2123	info->bytes = 0;
2124	info->bitmap_extents = 0;
2125	INIT_LIST_HEAD(&info->list);
2126	link_free_space(ctl, info);
2127	ctl->total_bitmaps++;
2128	recalculate_thresholds(ctl);
 
2129}
2130
2131static void free_bitmap(struct btrfs_free_space_ctl *ctl,
2132			struct btrfs_free_space *bitmap_info)
2133{
2134	/*
2135	 * Normally when this is called, the bitmap is completely empty. However,
2136	 * if we are blowing up the free space cache for one reason or another
2137	 * via __btrfs_remove_free_space_cache(), then it may not be freed and
2138	 * we may leave stats on the table.
2139	 */
2140	if (bitmap_info->bytes && !btrfs_free_space_trimmed(bitmap_info)) {
2141		ctl->discardable_extents[BTRFS_STAT_CURR] -=
2142			bitmap_info->bitmap_extents;
2143		ctl->discardable_bytes[BTRFS_STAT_CURR] -= bitmap_info->bytes;
2144
2145	}
2146	unlink_free_space(ctl, bitmap_info, true);
2147	kmem_cache_free(btrfs_free_space_bitmap_cachep, bitmap_info->bitmap);
2148	kmem_cache_free(btrfs_free_space_cachep, bitmap_info);
2149	ctl->total_bitmaps--;
2150	recalculate_thresholds(ctl);
2151}
2152
2153static noinline int remove_from_bitmap(struct btrfs_free_space_ctl *ctl,
2154			      struct btrfs_free_space *bitmap_info,
2155			      u64 *offset, u64 *bytes)
2156{
2157	u64 end;
2158	u64 search_start, search_bytes;
2159	int ret;
2160
2161again:
2162	end = bitmap_info->offset + (u64)(BITS_PER_BITMAP * ctl->unit) - 1;
2163
2164	/*
2165	 * We need to search for bits in this bitmap.  We could only cover some
2166	 * of the extent in this bitmap thanks to how we add space, so we need
2167	 * to search for as much as it as we can and clear that amount, and then
2168	 * go searching for the next bit.
2169	 */
2170	search_start = *offset;
2171	search_bytes = ctl->unit;
2172	search_bytes = min(search_bytes, end - search_start + 1);
2173	ret = search_bitmap(ctl, bitmap_info, &search_start, &search_bytes,
2174			    false);
2175	if (ret < 0 || search_start != *offset)
2176		return -EINVAL;
2177
2178	/* We may have found more bits than what we need */
2179	search_bytes = min(search_bytes, *bytes);
2180
2181	/* Cannot clear past the end of the bitmap */
2182	search_bytes = min(search_bytes, end - search_start + 1);
2183
2184	bitmap_clear_bits(ctl, bitmap_info, search_start, search_bytes, true);
2185	*offset += search_bytes;
2186	*bytes -= search_bytes;
2187
2188	if (*bytes) {
2189		struct rb_node *next = rb_next(&bitmap_info->offset_index);
2190		if (!bitmap_info->bytes)
2191			free_bitmap(ctl, bitmap_info);
2192
2193		/*
2194		 * no entry after this bitmap, but we still have bytes to
2195		 * remove, so something has gone wrong.
2196		 */
2197		if (!next)
2198			return -EINVAL;
2199
2200		bitmap_info = rb_entry(next, struct btrfs_free_space,
2201				       offset_index);
2202
2203		/*
2204		 * if the next entry isn't a bitmap we need to return to let the
2205		 * extent stuff do its work.
2206		 */
2207		if (!bitmap_info->bitmap)
2208			return -EAGAIN;
2209
2210		/*
2211		 * Ok the next item is a bitmap, but it may not actually hold
2212		 * the information for the rest of this free space stuff, so
2213		 * look for it, and if we don't find it return so we can try
2214		 * everything over again.
2215		 */
2216		search_start = *offset;
2217		search_bytes = ctl->unit;
2218		ret = search_bitmap(ctl, bitmap_info, &search_start,
2219				    &search_bytes, false);
2220		if (ret < 0 || search_start != *offset)
2221			return -EAGAIN;
2222
2223		goto again;
2224	} else if (!bitmap_info->bytes)
2225		free_bitmap(ctl, bitmap_info);
2226
2227	return 0;
2228}
2229
2230static u64 add_bytes_to_bitmap(struct btrfs_free_space_ctl *ctl,
2231			       struct btrfs_free_space *info, u64 offset,
2232			       u64 bytes, enum btrfs_trim_state trim_state)
2233{
2234	u64 bytes_to_set = 0;
2235	u64 end;
2236
2237	/*
2238	 * This is a tradeoff to make bitmap trim state minimal.  We mark the
2239	 * whole bitmap untrimmed if at any point we add untrimmed regions.
2240	 */
2241	if (trim_state == BTRFS_TRIM_STATE_UNTRIMMED) {
2242		if (btrfs_free_space_trimmed(info)) {
2243			ctl->discardable_extents[BTRFS_STAT_CURR] +=
2244				info->bitmap_extents;
2245			ctl->discardable_bytes[BTRFS_STAT_CURR] += info->bytes;
2246		}
2247		info->trim_state = BTRFS_TRIM_STATE_UNTRIMMED;
2248	}
2249
2250	end = info->offset + (u64)(BITS_PER_BITMAP * ctl->unit);
2251
2252	bytes_to_set = min(end - offset, bytes);
2253
2254	bitmap_set_bits(ctl, info, offset, bytes_to_set);
2255
2256	return bytes_to_set;
2257
2258}
2259
2260static bool use_bitmap(struct btrfs_free_space_ctl *ctl,
2261		      struct btrfs_free_space *info)
2262{
2263	struct btrfs_block_group *block_group = ctl->block_group;
2264	struct btrfs_fs_info *fs_info = block_group->fs_info;
2265	bool forced = false;
2266
2267#ifdef CONFIG_BTRFS_DEBUG
2268	if (btrfs_should_fragment_free_space(block_group))
2269		forced = true;
2270#endif
2271
2272	/* This is a way to reclaim large regions from the bitmaps. */
2273	if (!forced && info->bytes >= FORCE_EXTENT_THRESHOLD)
2274		return false;
2275
2276	/*
2277	 * If we are below the extents threshold then we can add this as an
2278	 * extent, and don't have to deal with the bitmap
2279	 */
2280	if (!forced && ctl->free_extents < ctl->extents_thresh) {
2281		/*
2282		 * If this block group has some small extents we don't want to
2283		 * use up all of our free slots in the cache with them, we want
2284		 * to reserve them to larger extents, however if we have plenty
2285		 * of cache left then go ahead an dadd them, no sense in adding
2286		 * the overhead of a bitmap if we don't have to.
2287		 */
2288		if (info->bytes <= fs_info->sectorsize * 8) {
2289			if (ctl->free_extents * 3 <= ctl->extents_thresh)
2290				return false;
2291		} else {
2292			return false;
2293		}
2294	}
2295
2296	/*
2297	 * The original block groups from mkfs can be really small, like 8
2298	 * megabytes, so don't bother with a bitmap for those entries.  However
2299	 * some block groups can be smaller than what a bitmap would cover but
2300	 * are still large enough that they could overflow the 32k memory limit,
2301	 * so allow those block groups to still be allowed to have a bitmap
2302	 * entry.
2303	 */
2304	if (((BITS_PER_BITMAP * ctl->unit) >> 1) > block_group->length)
 
2305		return false;
2306
2307	return true;
2308}
2309
2310static const struct btrfs_free_space_op free_space_op = {
 
2311	.use_bitmap		= use_bitmap,
2312};
2313
2314static int insert_into_bitmap(struct btrfs_free_space_ctl *ctl,
2315			      struct btrfs_free_space *info)
2316{
2317	struct btrfs_free_space *bitmap_info;
2318	struct btrfs_block_group *block_group = NULL;
2319	int added = 0;
2320	u64 bytes, offset, bytes_added;
2321	enum btrfs_trim_state trim_state;
2322	int ret;
2323
2324	bytes = info->bytes;
2325	offset = info->offset;
2326	trim_state = info->trim_state;
2327
2328	if (!ctl->op->use_bitmap(ctl, info))
2329		return 0;
2330
2331	if (ctl->op == &free_space_op)
2332		block_group = ctl->block_group;
2333again:
2334	/*
2335	 * Since we link bitmaps right into the cluster we need to see if we
2336	 * have a cluster here, and if so and it has our bitmap we need to add
2337	 * the free space to that bitmap.
2338	 */
2339	if (block_group && !list_empty(&block_group->cluster_list)) {
2340		struct btrfs_free_cluster *cluster;
2341		struct rb_node *node;
2342		struct btrfs_free_space *entry;
2343
2344		cluster = list_entry(block_group->cluster_list.next,
2345				     struct btrfs_free_cluster,
2346				     block_group_list);
2347		spin_lock(&cluster->lock);
2348		node = rb_first(&cluster->root);
2349		if (!node) {
2350			spin_unlock(&cluster->lock);
2351			goto no_cluster_bitmap;
2352		}
2353
2354		entry = rb_entry(node, struct btrfs_free_space, offset_index);
2355		if (!entry->bitmap) {
2356			spin_unlock(&cluster->lock);
2357			goto no_cluster_bitmap;
2358		}
2359
2360		if (entry->offset == offset_to_bitmap(ctl, offset)) {
2361			bytes_added = add_bytes_to_bitmap(ctl, entry, offset,
2362							  bytes, trim_state);
2363			bytes -= bytes_added;
2364			offset += bytes_added;
2365		}
2366		spin_unlock(&cluster->lock);
2367		if (!bytes) {
2368			ret = 1;
2369			goto out;
2370		}
2371	}
2372
2373no_cluster_bitmap:
2374	bitmap_info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
2375					 1, 0);
2376	if (!bitmap_info) {
2377		ASSERT(added == 0);
2378		goto new_bitmap;
2379	}
2380
2381	bytes_added = add_bytes_to_bitmap(ctl, bitmap_info, offset, bytes,
2382					  trim_state);
2383	bytes -= bytes_added;
2384	offset += bytes_added;
2385	added = 0;
2386
2387	if (!bytes) {
2388		ret = 1;
2389		goto out;
2390	} else
2391		goto again;
2392
2393new_bitmap:
2394	if (info && info->bitmap) {
2395		add_new_bitmap(ctl, info, offset);
2396		added = 1;
2397		info = NULL;
2398		goto again;
2399	} else {
2400		spin_unlock(&ctl->tree_lock);
2401
2402		/* no pre-allocated info, allocate a new one */
2403		if (!info) {
2404			info = kmem_cache_zalloc(btrfs_free_space_cachep,
2405						 GFP_NOFS);
2406			if (!info) {
2407				spin_lock(&ctl->tree_lock);
2408				ret = -ENOMEM;
2409				goto out;
2410			}
2411		}
2412
2413		/* allocate the bitmap */
2414		info->bitmap = kmem_cache_zalloc(btrfs_free_space_bitmap_cachep,
2415						 GFP_NOFS);
2416		info->trim_state = BTRFS_TRIM_STATE_TRIMMED;
2417		spin_lock(&ctl->tree_lock);
2418		if (!info->bitmap) {
2419			ret = -ENOMEM;
2420			goto out;
2421		}
2422		goto again;
2423	}
2424
2425out:
2426	if (info) {
2427		if (info->bitmap)
2428			kmem_cache_free(btrfs_free_space_bitmap_cachep,
2429					info->bitmap);
2430		kmem_cache_free(btrfs_free_space_cachep, info);
2431	}
2432
2433	return ret;
2434}
2435
2436/*
2437 * Free space merging rules:
2438 *  1) Merge trimmed areas together
2439 *  2) Let untrimmed areas coalesce with trimmed areas
2440 *  3) Always pull neighboring regions from bitmaps
2441 *
2442 * The above rules are for when we merge free space based on btrfs_trim_state.
2443 * Rules 2 and 3 are subtle because they are suboptimal, but are done for the
2444 * same reason: to promote larger extent regions which makes life easier for
2445 * find_free_extent().  Rule 2 enables coalescing based on the common path
2446 * being returning free space from btrfs_finish_extent_commit().  So when free
2447 * space is trimmed, it will prevent aggregating trimmed new region and
2448 * untrimmed regions in the rb_tree.  Rule 3 is purely to obtain larger extents
2449 * and provide find_free_extent() with the largest extents possible hoping for
2450 * the reuse path.
2451 */
2452static bool try_merge_free_space(struct btrfs_free_space_ctl *ctl,
2453			  struct btrfs_free_space *info, bool update_stat)
2454{
2455	struct btrfs_free_space *left_info = NULL;
2456	struct btrfs_free_space *right_info;
2457	bool merged = false;
2458	u64 offset = info->offset;
2459	u64 bytes = info->bytes;
2460	const bool is_trimmed = btrfs_free_space_trimmed(info);
2461	struct rb_node *right_prev = NULL;
2462
2463	/*
2464	 * first we want to see if there is free space adjacent to the range we
2465	 * are adding, if there is remove that struct and add a new one to
2466	 * cover the entire range
2467	 */
2468	right_info = tree_search_offset(ctl, offset + bytes, 0, 0);
2469	if (right_info)
2470		right_prev = rb_prev(&right_info->offset_index);
2471
2472	if (right_prev)
2473		left_info = rb_entry(right_prev, struct btrfs_free_space, offset_index);
2474	else if (!right_info)
2475		left_info = tree_search_offset(ctl, offset - 1, 0, 0);
2476
2477	/* See try_merge_free_space() comment. */
2478	if (right_info && !right_info->bitmap &&
2479	    (!is_trimmed || btrfs_free_space_trimmed(right_info))) {
2480		unlink_free_space(ctl, right_info, update_stat);
 
2481		info->bytes += right_info->bytes;
2482		kmem_cache_free(btrfs_free_space_cachep, right_info);
2483		merged = true;
2484	}
2485
2486	/* See try_merge_free_space() comment. */
2487	if (left_info && !left_info->bitmap &&
2488	    left_info->offset + left_info->bytes == offset &&
2489	    (!is_trimmed || btrfs_free_space_trimmed(left_info))) {
2490		unlink_free_space(ctl, left_info, update_stat);
 
 
2491		info->offset = left_info->offset;
2492		info->bytes += left_info->bytes;
2493		kmem_cache_free(btrfs_free_space_cachep, left_info);
2494		merged = true;
2495	}
2496
2497	return merged;
2498}
2499
2500static bool steal_from_bitmap_to_end(struct btrfs_free_space_ctl *ctl,
2501				     struct btrfs_free_space *info,
2502				     bool update_stat)
2503{
2504	struct btrfs_free_space *bitmap;
2505	unsigned long i;
2506	unsigned long j;
2507	const u64 end = info->offset + info->bytes;
2508	const u64 bitmap_offset = offset_to_bitmap(ctl, end);
2509	u64 bytes;
2510
2511	bitmap = tree_search_offset(ctl, bitmap_offset, 1, 0);
2512	if (!bitmap)
2513		return false;
2514
2515	i = offset_to_bit(bitmap->offset, ctl->unit, end);
2516	j = find_next_zero_bit(bitmap->bitmap, BITS_PER_BITMAP, i);
2517	if (j == i)
2518		return false;
2519	bytes = (j - i) * ctl->unit;
2520	info->bytes += bytes;
2521
2522	/* See try_merge_free_space() comment. */
2523	if (!btrfs_free_space_trimmed(bitmap))
2524		info->trim_state = BTRFS_TRIM_STATE_UNTRIMMED;
2525
2526	bitmap_clear_bits(ctl, bitmap, end, bytes, update_stat);
2527
2528	if (!bitmap->bytes)
2529		free_bitmap(ctl, bitmap);
2530
2531	return true;
2532}
2533
2534static bool steal_from_bitmap_to_front(struct btrfs_free_space_ctl *ctl,
2535				       struct btrfs_free_space *info,
2536				       bool update_stat)
2537{
2538	struct btrfs_free_space *bitmap;
2539	u64 bitmap_offset;
2540	unsigned long i;
2541	unsigned long j;
2542	unsigned long prev_j;
2543	u64 bytes;
2544
2545	bitmap_offset = offset_to_bitmap(ctl, info->offset);
2546	/* If we're on a boundary, try the previous logical bitmap. */
2547	if (bitmap_offset == info->offset) {
2548		if (info->offset == 0)
2549			return false;
2550		bitmap_offset = offset_to_bitmap(ctl, info->offset - 1);
2551	}
2552
2553	bitmap = tree_search_offset(ctl, bitmap_offset, 1, 0);
2554	if (!bitmap)
2555		return false;
2556
2557	i = offset_to_bit(bitmap->offset, ctl->unit, info->offset) - 1;
2558	j = 0;
2559	prev_j = (unsigned long)-1;
2560	for_each_clear_bit_from(j, bitmap->bitmap, BITS_PER_BITMAP) {
2561		if (j > i)
2562			break;
2563		prev_j = j;
2564	}
2565	if (prev_j == i)
2566		return false;
2567
2568	if (prev_j == (unsigned long)-1)
2569		bytes = (i + 1) * ctl->unit;
2570	else
2571		bytes = (i - prev_j) * ctl->unit;
2572
2573	info->offset -= bytes;
2574	info->bytes += bytes;
2575
2576	/* See try_merge_free_space() comment. */
2577	if (!btrfs_free_space_trimmed(bitmap))
2578		info->trim_state = BTRFS_TRIM_STATE_UNTRIMMED;
2579
2580	bitmap_clear_bits(ctl, bitmap, info->offset, bytes, update_stat);
2581
2582	if (!bitmap->bytes)
2583		free_bitmap(ctl, bitmap);
2584
2585	return true;
2586}
2587
2588/*
2589 * We prefer always to allocate from extent entries, both for clustered and
2590 * non-clustered allocation requests. So when attempting to add a new extent
2591 * entry, try to see if there's adjacent free space in bitmap entries, and if
2592 * there is, migrate that space from the bitmaps to the extent.
2593 * Like this we get better chances of satisfying space allocation requests
2594 * because we attempt to satisfy them based on a single cache entry, and never
2595 * on 2 or more entries - even if the entries represent a contiguous free space
2596 * region (e.g. 1 extent entry + 1 bitmap entry starting where the extent entry
2597 * ends).
2598 */
2599static void steal_from_bitmap(struct btrfs_free_space_ctl *ctl,
2600			      struct btrfs_free_space *info,
2601			      bool update_stat)
2602{
2603	/*
2604	 * Only work with disconnected entries, as we can change their offset,
2605	 * and must be extent entries.
2606	 */
2607	ASSERT(!info->bitmap);
2608	ASSERT(RB_EMPTY_NODE(&info->offset_index));
2609
2610	if (ctl->total_bitmaps > 0) {
2611		bool stole_end;
2612		bool stole_front = false;
2613
2614		stole_end = steal_from_bitmap_to_end(ctl, info, update_stat);
2615		if (ctl->total_bitmaps > 0)
2616			stole_front = steal_from_bitmap_to_front(ctl, info,
2617								 update_stat);
2618
2619		if (stole_end || stole_front)
2620			try_merge_free_space(ctl, info, update_stat);
2621	}
2622}
2623
2624int __btrfs_add_free_space(struct btrfs_block_group *block_group,
2625			   u64 offset, u64 bytes,
2626			   enum btrfs_trim_state trim_state)
2627{
2628	struct btrfs_fs_info *fs_info = block_group->fs_info;
2629	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2630	struct btrfs_free_space *info;
2631	int ret = 0;
2632	u64 filter_bytes = bytes;
2633
2634	ASSERT(!btrfs_is_zoned(fs_info));
2635
2636	info = kmem_cache_zalloc(btrfs_free_space_cachep, GFP_NOFS);
2637	if (!info)
2638		return -ENOMEM;
2639
2640	info->offset = offset;
2641	info->bytes = bytes;
2642	info->trim_state = trim_state;
2643	RB_CLEAR_NODE(&info->offset_index);
2644	RB_CLEAR_NODE(&info->bytes_index);
2645
2646	spin_lock(&ctl->tree_lock);
2647
2648	if (try_merge_free_space(ctl, info, true))
2649		goto link;
2650
2651	/*
2652	 * There was no extent directly to the left or right of this new
2653	 * extent then we know we're going to have to allocate a new extent, so
2654	 * before we do that see if we need to drop this into a bitmap
2655	 */
2656	ret = insert_into_bitmap(ctl, info);
2657	if (ret < 0) {
2658		goto out;
2659	} else if (ret) {
2660		ret = 0;
2661		goto out;
2662	}
2663link:
2664	/*
2665	 * Only steal free space from adjacent bitmaps if we're sure we're not
2666	 * going to add the new free space to existing bitmap entries - because
2667	 * that would mean unnecessary work that would be reverted. Therefore
2668	 * attempt to steal space from bitmaps if we're adding an extent entry.
2669	 */
2670	steal_from_bitmap(ctl, info, true);
2671
2672	filter_bytes = max(filter_bytes, info->bytes);
2673
2674	ret = link_free_space(ctl, info);
2675	if (ret)
2676		kmem_cache_free(btrfs_free_space_cachep, info);
2677out:
2678	btrfs_discard_update_discardable(block_group);
2679	spin_unlock(&ctl->tree_lock);
2680
2681	if (ret) {
2682		btrfs_crit(fs_info, "unable to add free space :%d", ret);
2683		ASSERT(ret != -EEXIST);
2684	}
2685
2686	if (trim_state != BTRFS_TRIM_STATE_TRIMMED) {
2687		btrfs_discard_check_filter(block_group, filter_bytes);
2688		btrfs_discard_queue_work(&fs_info->discard_ctl, block_group);
2689	}
2690
2691	return ret;
2692}
2693
2694static int __btrfs_add_free_space_zoned(struct btrfs_block_group *block_group,
2695					u64 bytenr, u64 size, bool used)
2696{
2697	struct btrfs_space_info *sinfo = block_group->space_info;
2698	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2699	u64 offset = bytenr - block_group->start;
2700	u64 to_free, to_unusable;
2701	int bg_reclaim_threshold = 0;
2702	bool initial = (size == block_group->length);
2703	u64 reclaimable_unusable;
2704
2705	WARN_ON(!initial && offset + size > block_group->zone_capacity);
2706
2707	if (!initial)
2708		bg_reclaim_threshold = READ_ONCE(sinfo->bg_reclaim_threshold);
2709
2710	spin_lock(&ctl->tree_lock);
2711	if (!used)
2712		to_free = size;
2713	else if (initial)
2714		to_free = block_group->zone_capacity;
2715	else if (offset >= block_group->alloc_offset)
2716		to_free = size;
2717	else if (offset + size <= block_group->alloc_offset)
2718		to_free = 0;
2719	else
2720		to_free = offset + size - block_group->alloc_offset;
2721	to_unusable = size - to_free;
2722
2723	ctl->free_space += to_free;
2724	/*
2725	 * If the block group is read-only, we should account freed space into
2726	 * bytes_readonly.
2727	 */
2728	if (!block_group->ro)
2729		block_group->zone_unusable += to_unusable;
2730	spin_unlock(&ctl->tree_lock);
2731	if (!used) {
2732		spin_lock(&block_group->lock);
2733		block_group->alloc_offset -= size;
2734		spin_unlock(&block_group->lock);
2735	}
2736
2737	reclaimable_unusable = block_group->zone_unusable -
2738			       (block_group->length - block_group->zone_capacity);
2739	/* All the region is now unusable. Mark it as unused and reclaim */
2740	if (block_group->zone_unusable == block_group->length) {
2741		btrfs_mark_bg_unused(block_group);
2742	} else if (bg_reclaim_threshold &&
2743		   reclaimable_unusable >=
2744		   mult_perc(block_group->zone_capacity, bg_reclaim_threshold)) {
2745		btrfs_mark_bg_to_reclaim(block_group);
2746	}
2747
2748	return 0;
2749}
2750
2751int btrfs_add_free_space(struct btrfs_block_group *block_group,
2752			 u64 bytenr, u64 size)
2753{
2754	enum btrfs_trim_state trim_state = BTRFS_TRIM_STATE_UNTRIMMED;
2755
2756	if (btrfs_is_zoned(block_group->fs_info))
2757		return __btrfs_add_free_space_zoned(block_group, bytenr, size,
2758						    true);
2759
2760	if (btrfs_test_opt(block_group->fs_info, DISCARD_SYNC))
2761		trim_state = BTRFS_TRIM_STATE_TRIMMED;
2762
2763	return __btrfs_add_free_space(block_group, bytenr, size, trim_state);
2764}
2765
2766int btrfs_add_free_space_unused(struct btrfs_block_group *block_group,
2767				u64 bytenr, u64 size)
2768{
2769	if (btrfs_is_zoned(block_group->fs_info))
2770		return __btrfs_add_free_space_zoned(block_group, bytenr, size,
2771						    false);
2772
2773	return btrfs_add_free_space(block_group, bytenr, size);
2774}
2775
2776/*
2777 * This is a subtle distinction because when adding free space back in general,
2778 * we want it to be added as untrimmed for async. But in the case where we add
2779 * it on loading of a block group, we want to consider it trimmed.
2780 */
2781int btrfs_add_free_space_async_trimmed(struct btrfs_block_group *block_group,
2782				       u64 bytenr, u64 size)
2783{
2784	enum btrfs_trim_state trim_state = BTRFS_TRIM_STATE_UNTRIMMED;
2785
2786	if (btrfs_is_zoned(block_group->fs_info))
2787		return __btrfs_add_free_space_zoned(block_group, bytenr, size,
2788						    true);
2789
2790	if (btrfs_test_opt(block_group->fs_info, DISCARD_SYNC) ||
2791	    btrfs_test_opt(block_group->fs_info, DISCARD_ASYNC))
2792		trim_state = BTRFS_TRIM_STATE_TRIMMED;
2793
2794	return __btrfs_add_free_space(block_group, bytenr, size, trim_state);
2795}
2796
2797int btrfs_remove_free_space(struct btrfs_block_group *block_group,
2798			    u64 offset, u64 bytes)
2799{
2800	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2801	struct btrfs_free_space *info;
2802	int ret;
2803	bool re_search = false;
2804
2805	if (btrfs_is_zoned(block_group->fs_info)) {
2806		/*
2807		 * This can happen with conventional zones when replaying log.
2808		 * Since the allocation info of tree-log nodes are not recorded
2809		 * to the extent-tree, calculate_alloc_pointer() failed to
2810		 * advance the allocation pointer after last allocated tree log
2811		 * node blocks.
2812		 *
2813		 * This function is called from
2814		 * btrfs_pin_extent_for_log_replay() when replaying the log.
2815		 * Advance the pointer not to overwrite the tree-log nodes.
2816		 */
2817		if (block_group->start + block_group->alloc_offset <
2818		    offset + bytes) {
2819			block_group->alloc_offset =
2820				offset + bytes - block_group->start;
2821		}
2822		return 0;
2823	}
2824
2825	spin_lock(&ctl->tree_lock);
2826
2827again:
2828	ret = 0;
2829	if (!bytes)
2830		goto out_lock;
2831
2832	info = tree_search_offset(ctl, offset, 0, 0);
2833	if (!info) {
2834		/*
2835		 * oops didn't find an extent that matched the space we wanted
2836		 * to remove, look for a bitmap instead
2837		 */
2838		info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
2839					  1, 0);
2840		if (!info) {
2841			/*
2842			 * If we found a partial bit of our free space in a
2843			 * bitmap but then couldn't find the other part this may
2844			 * be a problem, so WARN about it.
 
 
2845			 */
2846			WARN_ON(re_search);
2847			goto out_lock;
2848		}
2849	}
2850
2851	re_search = false;
2852	if (!info->bitmap) {
2853		unlink_free_space(ctl, info, true);
2854		if (offset == info->offset) {
2855			u64 to_free = min(bytes, info->bytes);
2856
2857			info->bytes -= to_free;
2858			info->offset += to_free;
2859			if (info->bytes) {
2860				ret = link_free_space(ctl, info);
2861				WARN_ON(ret);
2862			} else {
2863				kmem_cache_free(btrfs_free_space_cachep, info);
2864			}
2865
2866			offset += to_free;
2867			bytes -= to_free;
2868			goto again;
2869		} else {
2870			u64 old_end = info->bytes + info->offset;
2871
2872			info->bytes = offset - info->offset;
2873			ret = link_free_space(ctl, info);
2874			WARN_ON(ret);
2875			if (ret)
2876				goto out_lock;
2877
2878			/* Not enough bytes in this entry to satisfy us */
2879			if (old_end < offset + bytes) {
2880				bytes -= old_end - offset;
2881				offset = old_end;
2882				goto again;
2883			} else if (old_end == offset + bytes) {
2884				/* all done */
2885				goto out_lock;
2886			}
2887			spin_unlock(&ctl->tree_lock);
2888
2889			ret = __btrfs_add_free_space(block_group,
2890						     offset + bytes,
2891						     old_end - (offset + bytes),
2892						     info->trim_state);
2893			WARN_ON(ret);
2894			goto out;
2895		}
2896	}
2897
2898	ret = remove_from_bitmap(ctl, info, &offset, &bytes);
2899	if (ret == -EAGAIN) {
2900		re_search = true;
2901		goto again;
2902	}
2903out_lock:
2904	btrfs_discard_update_discardable(block_group);
2905	spin_unlock(&ctl->tree_lock);
2906out:
2907	return ret;
2908}
2909
2910void btrfs_dump_free_space(struct btrfs_block_group *block_group,
2911			   u64 bytes)
2912{
2913	struct btrfs_fs_info *fs_info = block_group->fs_info;
2914	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2915	struct btrfs_free_space *info;
2916	struct rb_node *n;
2917	int count = 0;
2918
2919	/*
2920	 * Zoned btrfs does not use free space tree and cluster. Just print
2921	 * out the free space after the allocation offset.
2922	 */
2923	if (btrfs_is_zoned(fs_info)) {
2924		btrfs_info(fs_info, "free space %llu active %d",
2925			   block_group->zone_capacity - block_group->alloc_offset,
2926			   test_bit(BLOCK_GROUP_FLAG_ZONE_IS_ACTIVE,
2927				    &block_group->runtime_flags));
2928		return;
2929	}
2930
2931	spin_lock(&ctl->tree_lock);
2932	for (n = rb_first(&ctl->free_space_offset); n; n = rb_next(n)) {
2933		info = rb_entry(n, struct btrfs_free_space, offset_index);
2934		if (info->bytes >= bytes && !block_group->ro)
2935			count++;
2936		btrfs_crit(fs_info, "entry offset %llu, bytes %llu, bitmap %s",
2937			   info->offset, info->bytes,
 
2938		       (info->bitmap) ? "yes" : "no");
2939	}
2940	spin_unlock(&ctl->tree_lock);
2941	btrfs_info(fs_info, "block group has cluster?: %s",
2942	       list_empty(&block_group->cluster_list) ? "no" : "yes");
2943	btrfs_info(fs_info,
2944		   "%d free space entries at or bigger than %llu bytes",
2945		   count, bytes);
2946}
2947
2948void btrfs_init_free_space_ctl(struct btrfs_block_group *block_group,
2949			       struct btrfs_free_space_ctl *ctl)
2950{
2951	struct btrfs_fs_info *fs_info = block_group->fs_info;
2952
2953	spin_lock_init(&ctl->tree_lock);
2954	ctl->unit = fs_info->sectorsize;
2955	ctl->start = block_group->start;
2956	ctl->block_group = block_group;
2957	ctl->op = &free_space_op;
2958	ctl->free_space_bytes = RB_ROOT_CACHED;
2959	INIT_LIST_HEAD(&ctl->trimming_ranges);
2960	mutex_init(&ctl->cache_writeout_mutex);
2961
2962	/*
2963	 * we only want to have 32k of ram per block group for keeping
2964	 * track of free space, and if we pass 1/2 of that we want to
2965	 * start converting things over to using bitmaps
2966	 */
2967	ctl->extents_thresh = (SZ_32K / 2) / sizeof(struct btrfs_free_space);
 
2968}
2969
2970/*
2971 * for a given cluster, put all of its extents back into the free
2972 * space cache.  If the block group passed doesn't match the block group
2973 * pointed to by the cluster, someone else raced in and freed the
2974 * cluster already.  In that case, we just return without changing anything
2975 */
2976static void __btrfs_return_cluster_to_free_space(
2977			     struct btrfs_block_group *block_group,
 
2978			     struct btrfs_free_cluster *cluster)
2979{
2980	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
 
2981	struct rb_node *node;
2982
2983	lockdep_assert_held(&ctl->tree_lock);
2984
2985	spin_lock(&cluster->lock);
2986	if (cluster->block_group != block_group) {
2987		spin_unlock(&cluster->lock);
2988		return;
2989	}
2990
2991	cluster->block_group = NULL;
2992	cluster->window_start = 0;
2993	list_del_init(&cluster->block_group_list);
2994
2995	node = rb_first(&cluster->root);
2996	while (node) {
2997		struct btrfs_free_space *entry;
2998
2999		entry = rb_entry(node, struct btrfs_free_space, offset_index);
3000		node = rb_next(&entry->offset_index);
3001		rb_erase(&entry->offset_index, &cluster->root);
3002		RB_CLEAR_NODE(&entry->offset_index);
3003
3004		if (!entry->bitmap) {
3005			/* Merging treats extents as if they were new */
3006			if (!btrfs_free_space_trimmed(entry)) {
3007				ctl->discardable_extents[BTRFS_STAT_CURR]--;
3008				ctl->discardable_bytes[BTRFS_STAT_CURR] -=
3009					entry->bytes;
3010			}
3011
 
 
3012			try_merge_free_space(ctl, entry, false);
3013			steal_from_bitmap(ctl, entry, false);
3014
3015			/* As we insert directly, update these statistics */
3016			if (!btrfs_free_space_trimmed(entry)) {
3017				ctl->discardable_extents[BTRFS_STAT_CURR]++;
3018				ctl->discardable_bytes[BTRFS_STAT_CURR] +=
3019					entry->bytes;
3020			}
3021		}
3022		tree_insert_offset(ctl, NULL, entry);
3023		rb_add_cached(&entry->bytes_index, &ctl->free_space_bytes,
3024			      entry_less);
3025	}
3026	cluster->root = RB_ROOT;
 
 
3027	spin_unlock(&cluster->lock);
3028	btrfs_put_block_group(block_group);
 
3029}
3030
3031void btrfs_remove_free_space_cache(struct btrfs_block_group *block_group)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3032{
3033	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
3034	struct btrfs_free_cluster *cluster;
3035	struct list_head *head;
3036
3037	spin_lock(&ctl->tree_lock);
3038	while ((head = block_group->cluster_list.next) !=
3039	       &block_group->cluster_list) {
3040		cluster = list_entry(head, struct btrfs_free_cluster,
3041				     block_group_list);
3042
3043		WARN_ON(cluster->block_group != block_group);
3044		__btrfs_return_cluster_to_free_space(block_group, cluster);
3045
3046		cond_resched_lock(&ctl->tree_lock);
3047	}
3048	__btrfs_remove_free_space_cache(ctl);
3049	btrfs_discard_update_discardable(block_group);
3050	spin_unlock(&ctl->tree_lock);
3051
3052}
3053
3054/*
3055 * Walk @block_group's free space rb_tree to determine if everything is trimmed.
3056 */
3057bool btrfs_is_free_space_trimmed(struct btrfs_block_group *block_group)
3058{
3059	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
3060	struct btrfs_free_space *info;
3061	struct rb_node *node;
3062	bool ret = true;
3063
3064	spin_lock(&ctl->tree_lock);
3065	node = rb_first(&ctl->free_space_offset);
3066
3067	while (node) {
3068		info = rb_entry(node, struct btrfs_free_space, offset_index);
3069
3070		if (!btrfs_free_space_trimmed(info)) {
3071			ret = false;
3072			break;
3073		}
3074
3075		node = rb_next(node);
3076	}
3077
3078	spin_unlock(&ctl->tree_lock);
3079	return ret;
3080}
3081
3082u64 btrfs_find_space_for_alloc(struct btrfs_block_group *block_group,
3083			       u64 offset, u64 bytes, u64 empty_size,
3084			       u64 *max_extent_size)
3085{
3086	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
3087	struct btrfs_discard_ctl *discard_ctl =
3088					&block_group->fs_info->discard_ctl;
3089	struct btrfs_free_space *entry = NULL;
3090	u64 bytes_search = bytes + empty_size;
3091	u64 ret = 0;
3092	u64 align_gap = 0;
3093	u64 align_gap_len = 0;
3094	enum btrfs_trim_state align_gap_trim_state = BTRFS_TRIM_STATE_UNTRIMMED;
3095	bool use_bytes_index = (offset == block_group->start);
3096
3097	ASSERT(!btrfs_is_zoned(block_group->fs_info));
3098
3099	spin_lock(&ctl->tree_lock);
3100	entry = find_free_space(ctl, &offset, &bytes_search,
3101				block_group->full_stripe_len, max_extent_size,
3102				use_bytes_index);
3103	if (!entry)
3104		goto out;
3105
3106	ret = offset;
3107	if (entry->bitmap) {
3108		bitmap_clear_bits(ctl, entry, offset, bytes, true);
3109
3110		if (!btrfs_free_space_trimmed(entry))
3111			atomic64_add(bytes, &discard_ctl->discard_bytes_saved);
3112
3113		if (!entry->bytes)
3114			free_bitmap(ctl, entry);
3115	} else {
3116		unlink_free_space(ctl, entry, true);
3117		align_gap_len = offset - entry->offset;
3118		align_gap = entry->offset;
3119		align_gap_trim_state = entry->trim_state;
3120
3121		if (!btrfs_free_space_trimmed(entry))
3122			atomic64_add(bytes, &discard_ctl->discard_bytes_saved);
3123
3124		entry->offset = offset + bytes;
3125		WARN_ON(entry->bytes < bytes + align_gap_len);
3126
3127		entry->bytes -= bytes + align_gap_len;
3128		if (!entry->bytes)
3129			kmem_cache_free(btrfs_free_space_cachep, entry);
3130		else
3131			link_free_space(ctl, entry);
3132	}
 
3133out:
3134	btrfs_discard_update_discardable(block_group);
3135	spin_unlock(&ctl->tree_lock);
3136
3137	if (align_gap_len)
3138		__btrfs_add_free_space(block_group, align_gap, align_gap_len,
3139				       align_gap_trim_state);
3140	return ret;
3141}
3142
3143/*
3144 * given a cluster, put all of its extents back into the free space
3145 * cache.  If a block group is passed, this function will only free
3146 * a cluster that belongs to the passed block group.
3147 *
3148 * Otherwise, it'll get a reference on the block group pointed to by the
3149 * cluster and remove the cluster from it.
3150 */
3151void btrfs_return_cluster_to_free_space(
3152			       struct btrfs_block_group *block_group,
3153			       struct btrfs_free_cluster *cluster)
3154{
3155	struct btrfs_free_space_ctl *ctl;
 
3156
3157	/* first, get a safe pointer to the block group */
3158	spin_lock(&cluster->lock);
3159	if (!block_group) {
3160		block_group = cluster->block_group;
3161		if (!block_group) {
3162			spin_unlock(&cluster->lock);
3163			return;
3164		}
3165	} else if (cluster->block_group != block_group) {
3166		/* someone else has already freed it don't redo their work */
3167		spin_unlock(&cluster->lock);
3168		return;
3169	}
3170	btrfs_get_block_group(block_group);
3171	spin_unlock(&cluster->lock);
3172
3173	ctl = block_group->free_space_ctl;
3174
3175	/* now return any extents the cluster had on it */
3176	spin_lock(&ctl->tree_lock);
3177	__btrfs_return_cluster_to_free_space(block_group, cluster);
3178	spin_unlock(&ctl->tree_lock);
3179
3180	btrfs_discard_queue_work(&block_group->fs_info->discard_ctl, block_group);
3181
3182	/* finally drop our ref */
3183	btrfs_put_block_group(block_group);
 
3184}
3185
3186static u64 btrfs_alloc_from_bitmap(struct btrfs_block_group *block_group,
3187				   struct btrfs_free_cluster *cluster,
3188				   struct btrfs_free_space *entry,
3189				   u64 bytes, u64 min_start,
3190				   u64 *max_extent_size)
3191{
3192	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
3193	int err;
3194	u64 search_start = cluster->window_start;
3195	u64 search_bytes = bytes;
3196	u64 ret = 0;
3197
3198	search_start = min_start;
3199	search_bytes = bytes;
3200
3201	err = search_bitmap(ctl, entry, &search_start, &search_bytes, true);
3202	if (err) {
3203		*max_extent_size = max(get_max_extent_size(entry),
3204				       *max_extent_size);
3205		return 0;
3206	}
3207
3208	ret = search_start;
3209	bitmap_clear_bits(ctl, entry, ret, bytes, false);
3210
3211	return ret;
3212}
3213
3214/*
3215 * given a cluster, try to allocate 'bytes' from it, returns 0
3216 * if it couldn't find anything suitably large, or a logical disk offset
3217 * if things worked out
3218 */
3219u64 btrfs_alloc_from_cluster(struct btrfs_block_group *block_group,
3220			     struct btrfs_free_cluster *cluster, u64 bytes,
3221			     u64 min_start, u64 *max_extent_size)
3222{
3223	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
3224	struct btrfs_discard_ctl *discard_ctl =
3225					&block_group->fs_info->discard_ctl;
3226	struct btrfs_free_space *entry = NULL;
3227	struct rb_node *node;
3228	u64 ret = 0;
3229
3230	ASSERT(!btrfs_is_zoned(block_group->fs_info));
3231
3232	spin_lock(&cluster->lock);
3233	if (bytes > cluster->max_size)
3234		goto out;
3235
3236	if (cluster->block_group != block_group)
3237		goto out;
3238
3239	node = rb_first(&cluster->root);
3240	if (!node)
3241		goto out;
3242
3243	entry = rb_entry(node, struct btrfs_free_space, offset_index);
3244	while (1) {
3245		if (entry->bytes < bytes)
3246			*max_extent_size = max(get_max_extent_size(entry),
3247					       *max_extent_size);
3248
3249		if (entry->bytes < bytes ||
3250		    (!entry->bitmap && entry->offset < min_start)) {
3251			node = rb_next(&entry->offset_index);
3252			if (!node)
3253				break;
3254			entry = rb_entry(node, struct btrfs_free_space,
3255					 offset_index);
3256			continue;
3257		}
3258
3259		if (entry->bitmap) {
3260			ret = btrfs_alloc_from_bitmap(block_group,
3261						      cluster, entry, bytes,
3262						      cluster->window_start,
3263						      max_extent_size);
3264			if (ret == 0) {
3265				node = rb_next(&entry->offset_index);
3266				if (!node)
3267					break;
3268				entry = rb_entry(node, struct btrfs_free_space,
3269						 offset_index);
3270				continue;
3271			}
3272			cluster->window_start += bytes;
3273		} else {
3274			ret = entry->offset;
3275
3276			entry->offset += bytes;
3277			entry->bytes -= bytes;
3278		}
3279
 
 
3280		break;
3281	}
3282out:
3283	spin_unlock(&cluster->lock);
3284
3285	if (!ret)
3286		return 0;
3287
3288	spin_lock(&ctl->tree_lock);
3289
3290	if (!btrfs_free_space_trimmed(entry))
3291		atomic64_add(bytes, &discard_ctl->discard_bytes_saved);
3292
3293	ctl->free_space -= bytes;
3294	if (!entry->bitmap && !btrfs_free_space_trimmed(entry))
3295		ctl->discardable_bytes[BTRFS_STAT_CURR] -= bytes;
3296
3297	spin_lock(&cluster->lock);
3298	if (entry->bytes == 0) {
3299		rb_erase(&entry->offset_index, &cluster->root);
3300		ctl->free_extents--;
3301		if (entry->bitmap) {
3302			kmem_cache_free(btrfs_free_space_bitmap_cachep,
3303					entry->bitmap);
3304			ctl->total_bitmaps--;
3305			recalculate_thresholds(ctl);
3306		} else if (!btrfs_free_space_trimmed(entry)) {
3307			ctl->discardable_extents[BTRFS_STAT_CURR]--;
3308		}
3309		kmem_cache_free(btrfs_free_space_cachep, entry);
3310	}
3311
3312	spin_unlock(&cluster->lock);
3313	spin_unlock(&ctl->tree_lock);
3314
3315	return ret;
3316}
3317
3318static int btrfs_bitmap_cluster(struct btrfs_block_group *block_group,
3319				struct btrfs_free_space *entry,
3320				struct btrfs_free_cluster *cluster,
3321				u64 offset, u64 bytes,
3322				u64 cont1_bytes, u64 min_bytes)
3323{
3324	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
3325	unsigned long next_zero;
3326	unsigned long i;
3327	unsigned long want_bits;
3328	unsigned long min_bits;
3329	unsigned long found_bits;
3330	unsigned long max_bits = 0;
3331	unsigned long start = 0;
3332	unsigned long total_found = 0;
3333	int ret;
3334
3335	lockdep_assert_held(&ctl->tree_lock);
3336
3337	i = offset_to_bit(entry->offset, ctl->unit,
3338			  max_t(u64, offset, entry->offset));
3339	want_bits = bytes_to_bits(bytes, ctl->unit);
3340	min_bits = bytes_to_bits(min_bytes, ctl->unit);
3341
3342	/*
3343	 * Don't bother looking for a cluster in this bitmap if it's heavily
3344	 * fragmented.
3345	 */
3346	if (entry->max_extent_size &&
3347	    entry->max_extent_size < cont1_bytes)
3348		return -ENOSPC;
3349again:
3350	found_bits = 0;
3351	for_each_set_bit_from(i, entry->bitmap, BITS_PER_BITMAP) {
 
 
3352		next_zero = find_next_zero_bit(entry->bitmap,
3353					       BITS_PER_BITMAP, i);
3354		if (next_zero - i >= min_bits) {
3355			found_bits = next_zero - i;
3356			if (found_bits > max_bits)
3357				max_bits = found_bits;
3358			break;
3359		}
3360		if (next_zero - i > max_bits)
3361			max_bits = next_zero - i;
3362		i = next_zero;
3363	}
3364
3365	if (!found_bits) {
3366		entry->max_extent_size = (u64)max_bits * ctl->unit;
3367		return -ENOSPC;
3368	}
3369
3370	if (!total_found) {
3371		start = i;
3372		cluster->max_size = 0;
3373	}
3374
3375	total_found += found_bits;
3376
3377	if (cluster->max_size < found_bits * ctl->unit)
3378		cluster->max_size = found_bits * ctl->unit;
3379
3380	if (total_found < want_bits || cluster->max_size < cont1_bytes) {
3381		i = next_zero + 1;
3382		goto again;
3383	}
3384
3385	cluster->window_start = start * ctl->unit + entry->offset;
 
3386	rb_erase(&entry->offset_index, &ctl->free_space_offset);
3387	rb_erase_cached(&entry->bytes_index, &ctl->free_space_bytes);
3388
3389	/*
3390	 * We need to know if we're currently on the normal space index when we
3391	 * manipulate the bitmap so that we know we need to remove and re-insert
3392	 * it into the space_index tree.  Clear the bytes_index node here so the
3393	 * bitmap manipulation helpers know not to mess with the space_index
3394	 * until this bitmap entry is added back into the normal cache.
3395	 */
3396	RB_CLEAR_NODE(&entry->bytes_index);
3397
3398	ret = tree_insert_offset(ctl, cluster, entry);
3399	ASSERT(!ret); /* -EEXIST; Logic error */
3400
3401	trace_btrfs_setup_cluster(block_group, cluster,
3402				  total_found * ctl->unit, 1);
3403	return 0;
3404}
3405
3406/*
3407 * This searches the block group for just extents to fill the cluster with.
3408 * Try to find a cluster with at least bytes total bytes, at least one
3409 * extent of cont1_bytes, and other clusters of at least min_bytes.
3410 */
3411static noinline int
3412setup_cluster_no_bitmap(struct btrfs_block_group *block_group,
3413			struct btrfs_free_cluster *cluster,
3414			struct list_head *bitmaps, u64 offset, u64 bytes,
3415			u64 cont1_bytes, u64 min_bytes)
3416{
3417	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
3418	struct btrfs_free_space *first = NULL;
3419	struct btrfs_free_space *entry = NULL;
3420	struct btrfs_free_space *last;
3421	struct rb_node *node;
 
3422	u64 window_free;
3423	u64 max_extent;
3424	u64 total_size = 0;
3425
3426	lockdep_assert_held(&ctl->tree_lock);
3427
3428	entry = tree_search_offset(ctl, offset, 0, 1);
3429	if (!entry)
3430		return -ENOSPC;
3431
3432	/*
3433	 * We don't want bitmaps, so just move along until we find a normal
3434	 * extent entry.
3435	 */
3436	while (entry->bitmap || entry->bytes < min_bytes) {
3437		if (entry->bitmap && list_empty(&entry->list))
3438			list_add_tail(&entry->list, bitmaps);
3439		node = rb_next(&entry->offset_index);
3440		if (!node)
3441			return -ENOSPC;
3442		entry = rb_entry(node, struct btrfs_free_space, offset_index);
3443	}
3444
 
3445	window_free = entry->bytes;
3446	max_extent = entry->bytes;
3447	first = entry;
3448	last = entry;
3449
3450	for (node = rb_next(&entry->offset_index); node;
3451	     node = rb_next(&entry->offset_index)) {
3452		entry = rb_entry(node, struct btrfs_free_space, offset_index);
3453
3454		if (entry->bitmap) {
3455			if (list_empty(&entry->list))
3456				list_add_tail(&entry->list, bitmaps);
3457			continue;
3458		}
3459
3460		if (entry->bytes < min_bytes)
3461			continue;
3462
3463		last = entry;
3464		window_free += entry->bytes;
3465		if (entry->bytes > max_extent)
3466			max_extent = entry->bytes;
3467	}
3468
3469	if (window_free < bytes || max_extent < cont1_bytes)
3470		return -ENOSPC;
3471
3472	cluster->window_start = first->offset;
3473
3474	node = &first->offset_index;
3475
3476	/*
3477	 * now we've found our entries, pull them out of the free space
3478	 * cache and put them into the cluster rbtree
3479	 */
3480	do {
3481		int ret;
3482
3483		entry = rb_entry(node, struct btrfs_free_space, offset_index);
3484		node = rb_next(&entry->offset_index);
3485		if (entry->bitmap || entry->bytes < min_bytes)
3486			continue;
3487
3488		rb_erase(&entry->offset_index, &ctl->free_space_offset);
3489		rb_erase_cached(&entry->bytes_index, &ctl->free_space_bytes);
3490		ret = tree_insert_offset(ctl, cluster, entry);
3491		total_size += entry->bytes;
3492		ASSERT(!ret); /* -EEXIST; Logic error */
3493	} while (node && entry != last);
3494
3495	cluster->max_size = max_extent;
3496	trace_btrfs_setup_cluster(block_group, cluster, total_size, 0);
3497	return 0;
3498}
3499
3500/*
3501 * This specifically looks for bitmaps that may work in the cluster, we assume
3502 * that we have already failed to find extents that will work.
3503 */
3504static noinline int
3505setup_cluster_bitmap(struct btrfs_block_group *block_group,
3506		     struct btrfs_free_cluster *cluster,
3507		     struct list_head *bitmaps, u64 offset, u64 bytes,
3508		     u64 cont1_bytes, u64 min_bytes)
3509{
3510	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
3511	struct btrfs_free_space *entry = NULL;
3512	int ret = -ENOSPC;
3513	u64 bitmap_offset = offset_to_bitmap(ctl, offset);
3514
3515	if (ctl->total_bitmaps == 0)
3516		return -ENOSPC;
3517
3518	/*
3519	 * The bitmap that covers offset won't be in the list unless offset
3520	 * is just its start offset.
3521	 */
3522	if (!list_empty(bitmaps))
3523		entry = list_first_entry(bitmaps, struct btrfs_free_space, list);
3524
3525	if (!entry || entry->offset != bitmap_offset) {
3526		entry = tree_search_offset(ctl, bitmap_offset, 1, 0);
3527		if (entry && list_empty(&entry->list))
3528			list_add(&entry->list, bitmaps);
3529	}
3530
3531	list_for_each_entry(entry, bitmaps, list) {
3532		if (entry->bytes < bytes)
3533			continue;
3534		ret = btrfs_bitmap_cluster(block_group, entry, cluster, offset,
3535					   bytes, cont1_bytes, min_bytes);
3536		if (!ret)
3537			return 0;
3538	}
3539
3540	/*
3541	 * The bitmaps list has all the bitmaps that record free space
3542	 * starting after offset, so no more search is required.
3543	 */
3544	return -ENOSPC;
3545}
3546
3547/*
3548 * here we try to find a cluster of blocks in a block group.  The goal
3549 * is to find at least bytes+empty_size.
3550 * We might not find them all in one contiguous area.
3551 *
3552 * returns zero and sets up cluster if things worked out, otherwise
3553 * it returns -enospc
3554 */
3555int btrfs_find_space_cluster(struct btrfs_block_group *block_group,
 
 
3556			     struct btrfs_free_cluster *cluster,
3557			     u64 offset, u64 bytes, u64 empty_size)
3558{
3559	struct btrfs_fs_info *fs_info = block_group->fs_info;
3560	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
3561	struct btrfs_free_space *entry, *tmp;
3562	LIST_HEAD(bitmaps);
3563	u64 min_bytes;
3564	u64 cont1_bytes;
3565	int ret;
3566
3567	/*
3568	 * Choose the minimum extent size we'll require for this
3569	 * cluster.  For SSD_SPREAD, don't allow any fragmentation.
3570	 * For metadata, allow allocates with smaller extents.  For
3571	 * data, keep it dense.
3572	 */
3573	if (btrfs_test_opt(fs_info, SSD_SPREAD)) {
3574		cont1_bytes = bytes + empty_size;
3575		min_bytes = cont1_bytes;
3576	} else if (block_group->flags & BTRFS_BLOCK_GROUP_METADATA) {
3577		cont1_bytes = bytes;
3578		min_bytes = fs_info->sectorsize;
3579	} else {
3580		cont1_bytes = max(bytes, (bytes + empty_size) >> 2);
3581		min_bytes = fs_info->sectorsize;
3582	}
3583
3584	spin_lock(&ctl->tree_lock);
3585
3586	/*
3587	 * If we know we don't have enough space to make a cluster don't even
3588	 * bother doing all the work to try and find one.
3589	 */
3590	if (ctl->free_space < bytes) {
3591		spin_unlock(&ctl->tree_lock);
3592		return -ENOSPC;
3593	}
3594
3595	spin_lock(&cluster->lock);
3596
3597	/* someone already found a cluster, hooray */
3598	if (cluster->block_group) {
3599		ret = 0;
3600		goto out;
3601	}
3602
3603	trace_btrfs_find_cluster(block_group, offset, bytes, empty_size,
3604				 min_bytes);
3605
 
3606	ret = setup_cluster_no_bitmap(block_group, cluster, &bitmaps, offset,
3607				      bytes + empty_size,
3608				      cont1_bytes, min_bytes);
3609	if (ret)
3610		ret = setup_cluster_bitmap(block_group, cluster, &bitmaps,
3611					   offset, bytes + empty_size,
3612					   cont1_bytes, min_bytes);
3613
3614	/* Clear our temporary list */
3615	list_for_each_entry_safe(entry, tmp, &bitmaps, list)
3616		list_del_init(&entry->list);
3617
3618	if (!ret) {
3619		btrfs_get_block_group(block_group);
3620		list_add_tail(&cluster->block_group_list,
3621			      &block_group->cluster_list);
3622		cluster->block_group = block_group;
3623	} else {
3624		trace_btrfs_failed_cluster_setup(block_group);
3625	}
3626out:
3627	spin_unlock(&cluster->lock);
3628	spin_unlock(&ctl->tree_lock);
3629
3630	return ret;
3631}
3632
3633/*
3634 * simple code to zero out a cluster
3635 */
3636void btrfs_init_free_cluster(struct btrfs_free_cluster *cluster)
3637{
3638	spin_lock_init(&cluster->lock);
3639	spin_lock_init(&cluster->refill_lock);
3640	cluster->root = RB_ROOT;
3641	cluster->max_size = 0;
3642	cluster->fragmented = false;
3643	INIT_LIST_HEAD(&cluster->block_group_list);
3644	cluster->block_group = NULL;
3645}
3646
3647static int do_trimming(struct btrfs_block_group *block_group,
3648		       u64 *total_trimmed, u64 start, u64 bytes,
3649		       u64 reserved_start, u64 reserved_bytes,
3650		       enum btrfs_trim_state reserved_trim_state,
3651		       struct btrfs_trim_range *trim_entry)
3652{
3653	struct btrfs_space_info *space_info = block_group->space_info;
3654	struct btrfs_fs_info *fs_info = block_group->fs_info;
3655	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
3656	int ret;
3657	int update = 0;
3658	const u64 end = start + bytes;
3659	const u64 reserved_end = reserved_start + reserved_bytes;
3660	enum btrfs_trim_state trim_state = BTRFS_TRIM_STATE_UNTRIMMED;
3661	u64 trimmed = 0;
3662
3663	spin_lock(&space_info->lock);
3664	spin_lock(&block_group->lock);
3665	if (!block_group->ro) {
3666		block_group->reserved += reserved_bytes;
3667		space_info->bytes_reserved += reserved_bytes;
3668		update = 1;
3669	}
3670	spin_unlock(&block_group->lock);
3671	spin_unlock(&space_info->lock);
3672
3673	ret = btrfs_discard_extent(fs_info, start, bytes, &trimmed);
3674	if (!ret) {
 
3675		*total_trimmed += trimmed;
3676		trim_state = BTRFS_TRIM_STATE_TRIMMED;
3677	}
3678
3679	mutex_lock(&ctl->cache_writeout_mutex);
3680	if (reserved_start < start)
3681		__btrfs_add_free_space(block_group, reserved_start,
3682				       start - reserved_start,
3683				       reserved_trim_state);
3684	if (end < reserved_end)
3685		__btrfs_add_free_space(block_group, end, reserved_end - end,
3686				       reserved_trim_state);
3687	__btrfs_add_free_space(block_group, start, bytes, trim_state);
3688	list_del(&trim_entry->list);
3689	mutex_unlock(&ctl->cache_writeout_mutex);
3690
3691	if (update) {
3692		spin_lock(&space_info->lock);
3693		spin_lock(&block_group->lock);
3694		if (block_group->ro)
3695			space_info->bytes_readonly += reserved_bytes;
3696		block_group->reserved -= reserved_bytes;
3697		space_info->bytes_reserved -= reserved_bytes;
3698		spin_unlock(&block_group->lock);
3699		spin_unlock(&space_info->lock);
 
3700	}
3701
3702	return ret;
3703}
3704
3705/*
3706 * If @async is set, then we will trim 1 region and return.
3707 */
3708static int trim_no_bitmap(struct btrfs_block_group *block_group,
3709			  u64 *total_trimmed, u64 start, u64 end, u64 minlen,
3710			  bool async)
3711{
3712	struct btrfs_discard_ctl *discard_ctl =
3713					&block_group->fs_info->discard_ctl;
3714	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
3715	struct btrfs_free_space *entry;
3716	struct rb_node *node;
3717	int ret = 0;
3718	u64 extent_start;
3719	u64 extent_bytes;
3720	enum btrfs_trim_state extent_trim_state;
3721	u64 bytes;
3722	const u64 max_discard_size = READ_ONCE(discard_ctl->max_discard_size);
3723
3724	while (start < end) {
3725		struct btrfs_trim_range trim_entry;
3726
3727		mutex_lock(&ctl->cache_writeout_mutex);
3728		spin_lock(&ctl->tree_lock);
3729
3730		if (ctl->free_space < minlen)
3731			goto out_unlock;
 
 
3732
3733		entry = tree_search_offset(ctl, start, 0, 1);
3734		if (!entry)
3735			goto out_unlock;
 
 
3736
3737		/* Skip bitmaps and if async, already trimmed entries */
3738		while (entry->bitmap ||
3739		       (async && btrfs_free_space_trimmed(entry))) {
3740			node = rb_next(&entry->offset_index);
3741			if (!node)
3742				goto out_unlock;
 
 
3743			entry = rb_entry(node, struct btrfs_free_space,
3744					 offset_index);
3745		}
3746
3747		if (entry->offset >= end)
3748			goto out_unlock;
 
 
3749
3750		extent_start = entry->offset;
3751		extent_bytes = entry->bytes;
3752		extent_trim_state = entry->trim_state;
3753		if (async) {
3754			start = entry->offset;
3755			bytes = entry->bytes;
3756			if (bytes < minlen) {
3757				spin_unlock(&ctl->tree_lock);
3758				mutex_unlock(&ctl->cache_writeout_mutex);
3759				goto next;
3760			}
3761			unlink_free_space(ctl, entry, true);
3762			/*
3763			 * Let bytes = BTRFS_MAX_DISCARD_SIZE + X.
3764			 * If X < BTRFS_ASYNC_DISCARD_MIN_FILTER, we won't trim
3765			 * X when we come back around.  So trim it now.
3766			 */
3767			if (max_discard_size &&
3768			    bytes >= (max_discard_size +
3769				      BTRFS_ASYNC_DISCARD_MIN_FILTER)) {
3770				bytes = max_discard_size;
3771				extent_bytes = max_discard_size;
3772				entry->offset += max_discard_size;
3773				entry->bytes -= max_discard_size;
3774				link_free_space(ctl, entry);
3775			} else {
3776				kmem_cache_free(btrfs_free_space_cachep, entry);
3777			}
3778		} else {
3779			start = max(start, extent_start);
3780			bytes = min(extent_start + extent_bytes, end) - start;
3781			if (bytes < minlen) {
3782				spin_unlock(&ctl->tree_lock);
3783				mutex_unlock(&ctl->cache_writeout_mutex);
3784				goto next;
3785			}
3786
3787			unlink_free_space(ctl, entry, true);
3788			kmem_cache_free(btrfs_free_space_cachep, entry);
3789		}
3790
 
 
 
3791		spin_unlock(&ctl->tree_lock);
3792		trim_entry.start = extent_start;
3793		trim_entry.bytes = extent_bytes;
3794		list_add_tail(&trim_entry.list, &ctl->trimming_ranges);
3795		mutex_unlock(&ctl->cache_writeout_mutex);
3796
3797		ret = do_trimming(block_group, total_trimmed, start, bytes,
3798				  extent_start, extent_bytes, extent_trim_state,
3799				  &trim_entry);
3800		if (ret) {
3801			block_group->discard_cursor = start + bytes;
3802			break;
3803		}
3804next:
3805		start += bytes;
3806		block_group->discard_cursor = start;
3807		if (async && *total_trimmed)
3808			break;
3809
3810		if (fatal_signal_pending(current)) {
3811			ret = -ERESTARTSYS;
3812			break;
3813		}
3814
3815		cond_resched();
3816	}
3817
3818	return ret;
3819
3820out_unlock:
3821	block_group->discard_cursor = btrfs_block_group_end(block_group);
3822	spin_unlock(&ctl->tree_lock);
3823	mutex_unlock(&ctl->cache_writeout_mutex);
3824
3825	return ret;
3826}
3827
3828/*
3829 * If we break out of trimming a bitmap prematurely, we should reset the
3830 * trimming bit.  In a rather contrieved case, it's possible to race here so
3831 * reset the state to BTRFS_TRIM_STATE_UNTRIMMED.
3832 *
3833 * start = start of bitmap
3834 * end = near end of bitmap
3835 *
3836 * Thread 1:			Thread 2:
3837 * trim_bitmaps(start)
3838 *				trim_bitmaps(end)
3839 *				end_trimming_bitmap()
3840 * reset_trimming_bitmap()
3841 */
3842static void reset_trimming_bitmap(struct btrfs_free_space_ctl *ctl, u64 offset)
3843{
3844	struct btrfs_free_space *entry;
3845
3846	spin_lock(&ctl->tree_lock);
3847	entry = tree_search_offset(ctl, offset, 1, 0);
3848	if (entry) {
3849		if (btrfs_free_space_trimmed(entry)) {
3850			ctl->discardable_extents[BTRFS_STAT_CURR] +=
3851				entry->bitmap_extents;
3852			ctl->discardable_bytes[BTRFS_STAT_CURR] += entry->bytes;
3853		}
3854		entry->trim_state = BTRFS_TRIM_STATE_UNTRIMMED;
3855	}
3856
3857	spin_unlock(&ctl->tree_lock);
3858}
3859
3860static void end_trimming_bitmap(struct btrfs_free_space_ctl *ctl,
3861				struct btrfs_free_space *entry)
3862{
3863	if (btrfs_free_space_trimming_bitmap(entry)) {
3864		entry->trim_state = BTRFS_TRIM_STATE_TRIMMED;
3865		ctl->discardable_extents[BTRFS_STAT_CURR] -=
3866			entry->bitmap_extents;
3867		ctl->discardable_bytes[BTRFS_STAT_CURR] -= entry->bytes;
3868	}
3869}
3870
3871/*
3872 * If @async is set, then we will trim 1 region and return.
3873 */
3874static int trim_bitmaps(struct btrfs_block_group *block_group,
3875			u64 *total_trimmed, u64 start, u64 end, u64 minlen,
3876			u64 maxlen, bool async)
3877{
3878	struct btrfs_discard_ctl *discard_ctl =
3879					&block_group->fs_info->discard_ctl;
3880	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
3881	struct btrfs_free_space *entry;
3882	int ret = 0;
3883	int ret2;
3884	u64 bytes;
3885	u64 offset = offset_to_bitmap(ctl, start);
3886	const u64 max_discard_size = READ_ONCE(discard_ctl->max_discard_size);
3887
3888	while (offset < end) {
3889		bool next_bitmap = false;
3890		struct btrfs_trim_range trim_entry;
3891
3892		mutex_lock(&ctl->cache_writeout_mutex);
3893		spin_lock(&ctl->tree_lock);
3894
3895		if (ctl->free_space < minlen) {
3896			block_group->discard_cursor =
3897				btrfs_block_group_end(block_group);
3898			spin_unlock(&ctl->tree_lock);
3899			mutex_unlock(&ctl->cache_writeout_mutex);
3900			break;
3901		}
3902
3903		entry = tree_search_offset(ctl, offset, 1, 0);
3904		/*
3905		 * Bitmaps are marked trimmed lossily now to prevent constant
3906		 * discarding of the same bitmap (the reason why we are bound
3907		 * by the filters).  So, retrim the block group bitmaps when we
3908		 * are preparing to punt to the unused_bgs list.  This uses
3909		 * @minlen to determine if we are in BTRFS_DISCARD_INDEX_UNUSED
3910		 * which is the only discard index which sets minlen to 0.
3911		 */
3912		if (!entry || (async && minlen && start == offset &&
3913			       btrfs_free_space_trimmed(entry))) {
3914			spin_unlock(&ctl->tree_lock);
3915			mutex_unlock(&ctl->cache_writeout_mutex);
3916			next_bitmap = true;
3917			goto next;
3918		}
3919
3920		/*
3921		 * Async discard bitmap trimming begins at by setting the start
3922		 * to be key.objectid and the offset_to_bitmap() aligns to the
3923		 * start of the bitmap.  This lets us know we are fully
3924		 * scanning the bitmap rather than only some portion of it.
3925		 */
3926		if (start == offset)
3927			entry->trim_state = BTRFS_TRIM_STATE_TRIMMING;
3928
3929		bytes = minlen;
3930		ret2 = search_bitmap(ctl, entry, &start, &bytes, false);
3931		if (ret2 || start >= end) {
3932			/*
3933			 * We lossily consider a bitmap trimmed if we only skip
3934			 * over regions <= BTRFS_ASYNC_DISCARD_MIN_FILTER.
3935			 */
3936			if (ret2 && minlen <= BTRFS_ASYNC_DISCARD_MIN_FILTER)
3937				end_trimming_bitmap(ctl, entry);
3938			else
3939				entry->trim_state = BTRFS_TRIM_STATE_UNTRIMMED;
3940			spin_unlock(&ctl->tree_lock);
3941			mutex_unlock(&ctl->cache_writeout_mutex);
3942			next_bitmap = true;
3943			goto next;
3944		}
3945
3946		/*
3947		 * We already trimmed a region, but are using the locking above
3948		 * to reset the trim_state.
3949		 */
3950		if (async && *total_trimmed) {
3951			spin_unlock(&ctl->tree_lock);
3952			mutex_unlock(&ctl->cache_writeout_mutex);
3953			goto out;
3954		}
3955
3956		bytes = min(bytes, end - start);
3957		if (bytes < minlen || (async && maxlen && bytes > maxlen)) {
3958			spin_unlock(&ctl->tree_lock);
3959			mutex_unlock(&ctl->cache_writeout_mutex);
3960			goto next;
3961		}
3962
3963		/*
3964		 * Let bytes = BTRFS_MAX_DISCARD_SIZE + X.
3965		 * If X < @minlen, we won't trim X when we come back around.
3966		 * So trim it now.  We differ here from trimming extents as we
3967		 * don't keep individual state per bit.
3968		 */
3969		if (async &&
3970		    max_discard_size &&
3971		    bytes > (max_discard_size + minlen))
3972			bytes = max_discard_size;
3973
3974		bitmap_clear_bits(ctl, entry, start, bytes, true);
3975		if (entry->bytes == 0)
3976			free_bitmap(ctl, entry);
3977
3978		spin_unlock(&ctl->tree_lock);
3979		trim_entry.start = start;
3980		trim_entry.bytes = bytes;
3981		list_add_tail(&trim_entry.list, &ctl->trimming_ranges);
3982		mutex_unlock(&ctl->cache_writeout_mutex);
3983
3984		ret = do_trimming(block_group, total_trimmed, start, bytes,
3985				  start, bytes, 0, &trim_entry);
3986		if (ret) {
3987			reset_trimming_bitmap(ctl, offset);
3988			block_group->discard_cursor =
3989				btrfs_block_group_end(block_group);
3990			break;
3991		}
3992next:
3993		if (next_bitmap) {
3994			offset += BITS_PER_BITMAP * ctl->unit;
3995			start = offset;
3996		} else {
3997			start += bytes;
 
 
3998		}
3999		block_group->discard_cursor = start;
4000
4001		if (fatal_signal_pending(current)) {
4002			if (start != offset)
4003				reset_trimming_bitmap(ctl, offset);
4004			ret = -ERESTARTSYS;
4005			break;
4006		}
4007
4008		cond_resched();
4009	}
4010
4011	if (offset >= end)
4012		block_group->discard_cursor = end;
4013
4014out:
4015	return ret;
4016}
4017
4018int btrfs_trim_block_group(struct btrfs_block_group *block_group,
4019			   u64 *trimmed, u64 start, u64 end, u64 minlen)
4020{
4021	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
4022	int ret;
4023	u64 rem = 0;
4024
4025	ASSERT(!btrfs_is_zoned(block_group->fs_info));
4026
4027	*trimmed = 0;
4028
4029	spin_lock(&block_group->lock);
4030	if (test_bit(BLOCK_GROUP_FLAG_REMOVED, &block_group->runtime_flags)) {
4031		spin_unlock(&block_group->lock);
4032		return 0;
4033	}
4034	btrfs_freeze_block_group(block_group);
4035	spin_unlock(&block_group->lock);
4036
4037	ret = trim_no_bitmap(block_group, trimmed, start, end, minlen, false);
4038	if (ret)
4039		goto out;
4040
4041	ret = trim_bitmaps(block_group, trimmed, start, end, minlen, 0, false);
4042	div64_u64_rem(end, BITS_PER_BITMAP * ctl->unit, &rem);
4043	/* If we ended in the middle of a bitmap, reset the trimming flag */
4044	if (rem)
4045		reset_trimming_bitmap(ctl, offset_to_bitmap(ctl, end));
4046out:
4047	btrfs_unfreeze_block_group(block_group);
4048	return ret;
4049}
4050
4051int btrfs_trim_block_group_extents(struct btrfs_block_group *block_group,
4052				   u64 *trimmed, u64 start, u64 end, u64 minlen,
4053				   bool async)
4054{
4055	int ret;
4056
4057	*trimmed = 0;
4058
4059	spin_lock(&block_group->lock);
4060	if (test_bit(BLOCK_GROUP_FLAG_REMOVED, &block_group->runtime_flags)) {
4061		spin_unlock(&block_group->lock);
4062		return 0;
4063	}
4064	btrfs_freeze_block_group(block_group);
4065	spin_unlock(&block_group->lock);
4066
4067	ret = trim_no_bitmap(block_group, trimmed, start, end, minlen, async);
4068	btrfs_unfreeze_block_group(block_group);
4069
4070	return ret;
4071}
4072
4073int btrfs_trim_block_group_bitmaps(struct btrfs_block_group *block_group,
4074				   u64 *trimmed, u64 start, u64 end, u64 minlen,
4075				   u64 maxlen, bool async)
 
 
 
 
 
4076{
4077	int ret;
4078
4079	*trimmed = 0;
4080
4081	spin_lock(&block_group->lock);
4082	if (test_bit(BLOCK_GROUP_FLAG_REMOVED, &block_group->runtime_flags)) {
4083		spin_unlock(&block_group->lock);
4084		return 0;
4085	}
4086	btrfs_freeze_block_group(block_group);
4087	spin_unlock(&block_group->lock);
4088
4089	ret = trim_bitmaps(block_group, trimmed, start, end, minlen, maxlen,
4090			   async);
4091
4092	btrfs_unfreeze_block_group(block_group);
 
4093
4094	return ret;
4095}
4096
4097bool btrfs_free_space_cache_v1_active(struct btrfs_fs_info *fs_info)
4098{
4099	return btrfs_super_cache_generation(fs_info->super_copy);
4100}
4101
4102static int cleanup_free_space_cache_v1(struct btrfs_fs_info *fs_info,
4103				       struct btrfs_trans_handle *trans)
4104{
4105	struct btrfs_block_group *block_group;
4106	struct rb_node *node;
4107	int ret = 0;
 
 
 
 
 
4108
4109	btrfs_info(fs_info, "cleaning free space cache v1");
 
 
4110
4111	node = rb_first_cached(&fs_info->block_group_cache_tree);
4112	while (node) {
4113		block_group = rb_entry(node, struct btrfs_block_group, cache_node);
4114		ret = btrfs_remove_free_space_inode(trans, NULL, block_group);
4115		if (ret)
4116			goto out;
4117		node = rb_next(node);
4118	}
4119out:
4120	return ret;
 
 
4121}
4122
4123int btrfs_set_free_space_cache_v1_active(struct btrfs_fs_info *fs_info, bool active)
 
4124{
4125	struct btrfs_trans_handle *trans;
4126	int ret;
4127
4128	/*
4129	 * update_super_roots will appropriately set or unset
4130	 * super_copy->cache_generation based on SPACE_CACHE and
4131	 * BTRFS_FS_CLEANUP_SPACE_CACHE_V1. For this reason, we need a
4132	 * transaction commit whether we are enabling space cache v1 and don't
4133	 * have any other work to do, or are disabling it and removing free
4134	 * space inodes.
4135	 */
4136	trans = btrfs_start_transaction(fs_info->tree_root, 0);
4137	if (IS_ERR(trans))
4138		return PTR_ERR(trans);
4139
4140	if (!active) {
4141		set_bit(BTRFS_FS_CLEANUP_SPACE_CACHE_V1, &fs_info->flags);
4142		ret = cleanup_free_space_cache_v1(fs_info, trans);
4143		if (ret) {
4144			btrfs_abort_transaction(trans, ret);
4145			btrfs_end_transaction(trans);
4146			goto out;
4147		}
4148	}
4149
4150	ret = btrfs_commit_transaction(trans);
4151out:
4152	clear_bit(BTRFS_FS_CLEANUP_SPACE_CACHE_V1, &fs_info->flags);
4153
4154	return ret;
4155}
 
 
 
 
4156
4157int __init btrfs_free_space_init(void)
4158{
4159	btrfs_free_space_cachep = kmem_cache_create("btrfs_free_space",
4160			sizeof(struct btrfs_free_space), 0,
4161			SLAB_MEM_SPREAD, NULL);
4162	if (!btrfs_free_space_cachep)
4163		return -ENOMEM;
4164
4165	btrfs_free_space_bitmap_cachep = kmem_cache_create("btrfs_free_space_bitmap",
4166							PAGE_SIZE, PAGE_SIZE,
4167							SLAB_MEM_SPREAD, NULL);
4168	if (!btrfs_free_space_bitmap_cachep) {
4169		kmem_cache_destroy(btrfs_free_space_cachep);
4170		return -ENOMEM;
4171	}
4172
4173	return 0;
4174}
4175
4176void __cold btrfs_free_space_exit(void)
 
 
4177{
4178	kmem_cache_destroy(btrfs_free_space_cachep);
4179	kmem_cache_destroy(btrfs_free_space_bitmap_cachep);
4180}
4181
4182#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
4183/*
4184 * Use this if you need to make a bitmap or extent entry specifically, it
4185 * doesn't do any of the merging that add_free_space does, this acts a lot like
4186 * how the free space cache loading stuff works, so you can get really weird
4187 * configurations.
4188 */
4189int test_add_free_space_entry(struct btrfs_block_group *cache,
4190			      u64 offset, u64 bytes, bool bitmap)
4191{
4192	struct btrfs_free_space_ctl *ctl = cache->free_space_ctl;
4193	struct btrfs_free_space *info = NULL, *bitmap_info;
4194	void *map = NULL;
4195	enum btrfs_trim_state trim_state = BTRFS_TRIM_STATE_TRIMMED;
4196	u64 bytes_added;
4197	int ret;
4198
4199again:
4200	if (!info) {
4201		info = kmem_cache_zalloc(btrfs_free_space_cachep, GFP_NOFS);
4202		if (!info)
4203			return -ENOMEM;
4204	}
4205
4206	if (!bitmap) {
4207		spin_lock(&ctl->tree_lock);
4208		info->offset = offset;
4209		info->bytes = bytes;
4210		info->max_extent_size = 0;
4211		ret = link_free_space(ctl, info);
4212		spin_unlock(&ctl->tree_lock);
4213		if (ret)
4214			kmem_cache_free(btrfs_free_space_cachep, info);
4215		return ret;
4216	}
4217
4218	if (!map) {
4219		map = kmem_cache_zalloc(btrfs_free_space_bitmap_cachep, GFP_NOFS);
4220		if (!map) {
4221			kmem_cache_free(btrfs_free_space_cachep, info);
4222			return -ENOMEM;
4223		}
4224	}
4225
4226	spin_lock(&ctl->tree_lock);
4227	bitmap_info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
4228					 1, 0);
4229	if (!bitmap_info) {
4230		info->bitmap = map;
4231		map = NULL;
4232		add_new_bitmap(ctl, info, offset);
4233		bitmap_info = info;
4234		info = NULL;
4235	}
4236
4237	bytes_added = add_bytes_to_bitmap(ctl, bitmap_info, offset, bytes,
4238					  trim_state);
 
4239
4240	bytes -= bytes_added;
4241	offset += bytes_added;
4242	spin_unlock(&ctl->tree_lock);
4243
4244	if (bytes)
4245		goto again;
4246
4247	if (info)
4248		kmem_cache_free(btrfs_free_space_cachep, info);
4249	if (map)
4250		kmem_cache_free(btrfs_free_space_bitmap_cachep, map);
4251	return 0;
 
 
 
4252}
4253
4254/*
4255 * Checks to see if the given range is in the free space cache.  This is really
4256 * just used to check the absence of space, so if there is free space in the
4257 * range at all we will return 1.
4258 */
4259int test_check_exists(struct btrfs_block_group *cache,
4260		      u64 offset, u64 bytes)
4261{
4262	struct btrfs_free_space_ctl *ctl = cache->free_space_ctl;
4263	struct btrfs_free_space *info;
4264	int ret = 0;
4265
4266	spin_lock(&ctl->tree_lock);
4267	info = tree_search_offset(ctl, offset, 0, 0);
4268	if (!info) {
4269		info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
4270					  1, 0);
4271		if (!info)
4272			goto out;
4273	}
4274
4275have_info:
4276	if (info->bitmap) {
4277		u64 bit_off, bit_bytes;
4278		struct rb_node *n;
4279		struct btrfs_free_space *tmp;
4280
4281		bit_off = offset;
4282		bit_bytes = ctl->unit;
4283		ret = search_bitmap(ctl, info, &bit_off, &bit_bytes, false);
4284		if (!ret) {
4285			if (bit_off == offset) {
4286				ret = 1;
4287				goto out;
4288			} else if (bit_off > offset &&
4289				   offset + bytes > bit_off) {
4290				ret = 1;
4291				goto out;
4292			}
4293		}
4294
4295		n = rb_prev(&info->offset_index);
4296		while (n) {
4297			tmp = rb_entry(n, struct btrfs_free_space,
4298				       offset_index);
4299			if (tmp->offset + tmp->bytes < offset)
4300				break;
4301			if (offset + bytes < tmp->offset) {
4302				n = rb_prev(&tmp->offset_index);
4303				continue;
4304			}
4305			info = tmp;
4306			goto have_info;
4307		}
4308
4309		n = rb_next(&info->offset_index);
4310		while (n) {
4311			tmp = rb_entry(n, struct btrfs_free_space,
4312				       offset_index);
4313			if (offset + bytes < tmp->offset)
4314				break;
4315			if (tmp->offset + tmp->bytes < offset) {
4316				n = rb_next(&tmp->offset_index);
4317				continue;
4318			}
4319			info = tmp;
4320			goto have_info;
4321		}
4322
4323		ret = 0;
4324		goto out;
4325	}
4326
4327	if (info->offset == offset) {
4328		ret = 1;
4329		goto out;
 
 
 
 
4330	}
4331
4332	if (offset > info->offset && offset < info->offset + info->bytes)
4333		ret = 1;
4334out:
4335	spin_unlock(&ctl->tree_lock);
4336	return ret;
4337}
4338#endif /* CONFIG_BTRFS_FS_RUN_SANITY_TESTS */
v3.5.6
 
   1/*
   2 * Copyright (C) 2008 Red Hat.  All rights reserved.
   3 *
   4 * This program is free software; you can redistribute it and/or
   5 * modify it under the terms of the GNU General Public
   6 * License v2 as published by the Free Software Foundation.
   7 *
   8 * This program is distributed in the hope that it will be useful,
   9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11 * General Public License for more details.
  12 *
  13 * You should have received a copy of the GNU General Public
  14 * License along with this program; if not, write to the
  15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16 * Boston, MA 021110-1307, USA.
  17 */
  18
  19#include <linux/pagemap.h>
  20#include <linux/sched.h>
 
  21#include <linux/slab.h>
  22#include <linux/math64.h>
  23#include <linux/ratelimit.h>
 
 
  24#include "ctree.h"
 
 
 
  25#include "free-space-cache.h"
  26#include "transaction.h"
  27#include "disk-io.h"
  28#include "extent_io.h"
  29#include "inode-map.h"
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  30
  31#define BITS_PER_BITMAP		(PAGE_CACHE_SIZE * 8)
  32#define MAX_CACHE_BYTES_PER_GIG	(32 * 1024)
 
 
 
 
 
 
  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);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  38
  39static struct inode *__lookup_free_space_inode(struct btrfs_root *root,
  40					       struct btrfs_path *path,
  41					       u64 offset)
  42{
 
  43	struct btrfs_key key;
  44	struct btrfs_key location;
  45	struct btrfs_disk_key disk_key;
  46	struct btrfs_free_space_header *header;
  47	struct extent_buffer *leaf;
  48	struct inode *inode = NULL;
 
  49	int ret;
  50
  51	key.objectid = BTRFS_FREE_SPACE_OBJECTID;
  52	key.offset = offset;
  53	key.type = 0;
  54
  55	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
  56	if (ret < 0)
  57		return ERR_PTR(ret);
  58	if (ret > 0) {
  59		btrfs_release_path(path);
  60		return ERR_PTR(-ENOENT);
  61	}
  62
  63	leaf = path->nodes[0];
  64	header = btrfs_item_ptr(leaf, path->slots[0],
  65				struct btrfs_free_space_header);
  66	btrfs_free_space_key(leaf, header, &disk_key);
  67	btrfs_disk_key_to_cpu(&location, &disk_key);
  68	btrfs_release_path(path);
  69
  70	inode = btrfs_iget(root->fs_info->sb, &location, root, NULL);
  71	if (!inode)
  72		return ERR_PTR(-ENOENT);
 
 
 
 
 
  73	if (IS_ERR(inode))
  74		return inode;
  75	if (is_bad_inode(inode)) {
  76		iput(inode);
  77		return ERR_PTR(-ENOENT);
  78	}
  79
  80	mapping_set_gfp_mask(inode->i_mapping,
  81			mapping_gfp_mask(inode->i_mapping) & ~__GFP_FS);
 
  82
  83	return inode;
  84}
  85
  86struct inode *lookup_free_space_inode(struct btrfs_root *root,
  87				      struct btrfs_block_group_cache
  88				      *block_group, struct btrfs_path *path)
  89{
 
  90	struct inode *inode = NULL;
  91	u32 flags = BTRFS_INODE_NODATASUM | BTRFS_INODE_NODATACOW;
  92
  93	spin_lock(&block_group->lock);
  94	if (block_group->inode)
  95		inode = igrab(block_group->inode);
  96	spin_unlock(&block_group->lock);
  97	if (inode)
  98		return inode;
  99
 100	inode = __lookup_free_space_inode(root, path,
 101					  block_group->key.objectid);
 102	if (IS_ERR(inode))
 103		return inode;
 104
 105	spin_lock(&block_group->lock);
 106	if (!((BTRFS_I(inode)->flags & flags) == flags)) {
 107		printk(KERN_INFO "Old style space inode found, converting.\n");
 108		BTRFS_I(inode)->flags |= BTRFS_INODE_NODATASUM |
 109			BTRFS_INODE_NODATACOW;
 110		block_group->disk_cache_state = BTRFS_DC_CLEAR;
 111	}
 112
 113	if (!block_group->iref) {
 114		block_group->inode = igrab(inode);
 115		block_group->iref = 1;
 116	}
 117	spin_unlock(&block_group->lock);
 118
 119	return inode;
 120}
 121
 122int __create_free_space_inode(struct btrfs_root *root,
 123			      struct btrfs_trans_handle *trans,
 124			      struct btrfs_path *path, u64 ino, u64 offset)
 
 125{
 126	struct btrfs_key key;
 127	struct btrfs_disk_key disk_key;
 128	struct btrfs_free_space_header *header;
 129	struct btrfs_inode_item *inode_item;
 130	struct extent_buffer *leaf;
 131	u64 flags = BTRFS_INODE_NOCOMPRESS | BTRFS_INODE_PREALLOC;
 
 
 132	int ret;
 133
 134	ret = btrfs_insert_empty_inode(trans, root, path, ino);
 135	if (ret)
 136		return ret;
 137
 138	/* We inline crc's for the free disk space cache */
 139	if (ino != BTRFS_FREE_INO_OBJECTID)
 140		flags |= BTRFS_INODE_NODATASUM | BTRFS_INODE_NODATACOW;
 141
 142	leaf = path->nodes[0];
 143	inode_item = btrfs_item_ptr(leaf, path->slots[0],
 144				    struct btrfs_inode_item);
 145	btrfs_item_key(leaf, &disk_key, path->slots[0]);
 146	memset_extent_buffer(leaf, 0, (unsigned long)inode_item,
 147			     sizeof(*inode_item));
 148	btrfs_set_inode_generation(leaf, inode_item, trans->transid);
 149	btrfs_set_inode_size(leaf, inode_item, 0);
 150	btrfs_set_inode_nbytes(leaf, inode_item, 0);
 151	btrfs_set_inode_uid(leaf, inode_item, 0);
 152	btrfs_set_inode_gid(leaf, inode_item, 0);
 153	btrfs_set_inode_mode(leaf, inode_item, S_IFREG | 0600);
 154	btrfs_set_inode_flags(leaf, inode_item, flags);
 155	btrfs_set_inode_nlink(leaf, inode_item, 1);
 156	btrfs_set_inode_transid(leaf, inode_item, trans->transid);
 157	btrfs_set_inode_block_group(leaf, inode_item, offset);
 158	btrfs_mark_buffer_dirty(leaf);
 159	btrfs_release_path(path);
 160
 161	key.objectid = BTRFS_FREE_SPACE_OBJECTID;
 162	key.offset = offset;
 163	key.type = 0;
 164
 165	ret = btrfs_insert_empty_item(trans, root, path, &key,
 166				      sizeof(struct btrfs_free_space_header));
 167	if (ret < 0) {
 168		btrfs_release_path(path);
 169		return ret;
 170	}
 
 171	leaf = path->nodes[0];
 172	header = btrfs_item_ptr(leaf, path->slots[0],
 173				struct btrfs_free_space_header);
 174	memset_extent_buffer(leaf, 0, (unsigned long)header, sizeof(*header));
 175	btrfs_set_free_space_key(leaf, header, &disk_key);
 176	btrfs_mark_buffer_dirty(leaf);
 177	btrfs_release_path(path);
 178
 179	return 0;
 180}
 181
 182int create_free_space_inode(struct btrfs_root *root,
 183			    struct btrfs_trans_handle *trans,
 184			    struct btrfs_block_group_cache *block_group,
 185			    struct btrfs_path *path)
 186{
 187	int ret;
 188	u64 ino;
 189
 190	ret = btrfs_find_free_objectid(root, &ino);
 191	if (ret < 0)
 192		return ret;
 193
 194	return __create_free_space_inode(root, trans, path, ino,
 195					 block_group->key.objectid);
 196}
 197
 198int btrfs_truncate_free_space_cache(struct btrfs_root *root,
 199				    struct btrfs_trans_handle *trans,
 200				    struct btrfs_path *path,
 201				    struct inode *inode)
 202{
 203	struct btrfs_block_rsv *rsv;
 204	u64 needed_bytes;
 205	loff_t oldsize;
 
 
 
 206	int ret = 0;
 207
 208	rsv = trans->block_rsv;
 209	trans->block_rsv = &root->fs_info->global_block_rsv;
 
 210
 211	/* 1 for slack space, 1 for updating the inode */
 212	needed_bytes = btrfs_calc_trunc_metadata_size(root, 1) +
 213		btrfs_calc_trans_metadata_size(root, 1);
 214
 215	spin_lock(&trans->block_rsv->lock);
 216	if (trans->block_rsv->reserved < needed_bytes) {
 217		spin_unlock(&trans->block_rsv->lock);
 218		trans->block_rsv = rsv;
 219		return -ENOSPC;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 220	}
 221	spin_unlock(&trans->block_rsv->lock);
 222
 223	oldsize = i_size_read(inode);
 224	btrfs_i_size_write(inode, 0);
 225	truncate_pagecache(inode, oldsize, 0);
 
 
 
 226
 227	/*
 228	 * We don't need an orphan item because truncating the free space cache
 229	 * will never be split across transactions.
 230	 */
 231	ret = btrfs_truncate_inode_items(trans, root, inode,
 232					 0, BTRFS_EXTENT_DATA_KEY);
 
 
 233
 234	if (ret) {
 235		trans->block_rsv = rsv;
 236		btrfs_abort_transaction(trans, root, ret);
 237		return ret;
 238	}
 239
 240	ret = btrfs_update_inode(trans, root, inode);
 
 
 241	if (ret)
 242		btrfs_abort_transaction(trans, root, ret);
 243	trans->block_rsv = rsv;
 244
 245	return ret;
 246}
 247
 248static int readahead_cache(struct inode *inode)
 249{
 250	struct file_ra_state *ra;
 251	unsigned long last_index;
 252
 253	ra = kzalloc(sizeof(*ra), GFP_NOFS);
 254	if (!ra)
 255		return -ENOMEM;
 256
 257	file_ra_state_init(ra, inode->i_mapping);
 258	last_index = (i_size_read(inode) - 1) >> PAGE_CACHE_SHIFT;
 259
 260	page_cache_sync_readahead(inode->i_mapping, ra, NULL, 0, last_index);
 
 
 
 261
 262	kfree(ra);
 263
 264	return 0;
 265}
 
 266
 267struct io_ctl {
 268	void *cur, *orig;
 269	struct page *page;
 270	struct page **pages;
 271	struct btrfs_root *root;
 272	unsigned long size;
 273	int index;
 274	int num_pages;
 275	unsigned check_crcs:1;
 276};
 277
 278static int io_ctl_init(struct io_ctl *io_ctl, struct inode *inode,
 279		       struct btrfs_root *root)
 280{
 281	memset(io_ctl, 0, sizeof(struct io_ctl));
 282	io_ctl->num_pages = (i_size_read(inode) + PAGE_CACHE_SIZE - 1) >>
 283		PAGE_CACHE_SHIFT;
 284	io_ctl->pages = kzalloc(sizeof(struct page *) * io_ctl->num_pages,
 285				GFP_NOFS);
 286	if (!io_ctl->pages)
 287		return -ENOMEM;
 288	io_ctl->root = root;
 289	if (btrfs_ino(inode) != BTRFS_FREE_INO_OBJECTID)
 290		io_ctl->check_crcs = 1;
 
 
 291	return 0;
 292}
 
 293
 294static void io_ctl_free(struct io_ctl *io_ctl)
 295{
 296	kfree(io_ctl->pages);
 
 297}
 298
 299static void io_ctl_unmap_page(struct io_ctl *io_ctl)
 300{
 301	if (io_ctl->cur) {
 302		kunmap(io_ctl->page);
 303		io_ctl->cur = NULL;
 304		io_ctl->orig = NULL;
 305	}
 306}
 307
 308static void io_ctl_map_page(struct io_ctl *io_ctl, int clear)
 309{
 310	WARN_ON(io_ctl->cur);
 311	BUG_ON(io_ctl->index >= io_ctl->num_pages);
 312	io_ctl->page = io_ctl->pages[io_ctl->index++];
 313	io_ctl->cur = kmap(io_ctl->page);
 314	io_ctl->orig = io_ctl->cur;
 315	io_ctl->size = PAGE_CACHE_SIZE;
 316	if (clear)
 317		memset(io_ctl->cur, 0, PAGE_CACHE_SIZE);
 318}
 319
 320static void io_ctl_drop_pages(struct io_ctl *io_ctl)
 321{
 322	int i;
 323
 324	io_ctl_unmap_page(io_ctl);
 325
 326	for (i = 0; i < io_ctl->num_pages; i++) {
 327		if (io_ctl->pages[i]) {
 328			ClearPageChecked(io_ctl->pages[i]);
 
 
 
 329			unlock_page(io_ctl->pages[i]);
 330			page_cache_release(io_ctl->pages[i]);
 331		}
 332	}
 333}
 334
 335static int io_ctl_prepare_pages(struct io_ctl *io_ctl, struct inode *inode,
 336				int uptodate)
 337{
 338	struct page *page;
 
 339	gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
 340	int i;
 341
 342	for (i = 0; i < io_ctl->num_pages; i++) {
 
 
 343		page = find_or_create_page(inode->i_mapping, i, mask);
 344		if (!page) {
 345			io_ctl_drop_pages(io_ctl);
 346			return -ENOMEM;
 347		}
 
 
 
 
 
 
 
 
 
 348		io_ctl->pages[i] = page;
 349		if (uptodate && !PageUptodate(page)) {
 350			btrfs_readpage(NULL, page);
 351			lock_page(page);
 
 
 
 
 
 
 352			if (!PageUptodate(page)) {
 353				printk(KERN_ERR "btrfs: error reading free "
 354				       "space cache\n");
 355				io_ctl_drop_pages(io_ctl);
 356				return -EIO;
 357			}
 358		}
 359	}
 360
 361	for (i = 0; i < io_ctl->num_pages; i++) {
 362		clear_page_dirty_for_io(io_ctl->pages[i]);
 363		set_page_extent_mapped(io_ctl->pages[i]);
 364	}
 365
 366	return 0;
 367}
 368
 369static void io_ctl_set_generation(struct io_ctl *io_ctl, u64 generation)
 370{
 371	__le64 *val;
 372
 373	io_ctl_map_page(io_ctl, 1);
 374
 375	/*
 376	 * Skip the csum areas.  If we don't check crcs then we just have a
 377	 * 64bit chunk at the front of the first page.
 378	 */
 379	if (io_ctl->check_crcs) {
 380		io_ctl->cur += (sizeof(u32) * io_ctl->num_pages);
 381		io_ctl->size -= sizeof(u64) + (sizeof(u32) * io_ctl->num_pages);
 382	} else {
 383		io_ctl->cur += sizeof(u64);
 384		io_ctl->size -= sizeof(u64) * 2;
 385	}
 386
 387	val = io_ctl->cur;
 388	*val = cpu_to_le64(generation);
 389	io_ctl->cur += sizeof(u64);
 390}
 391
 392static int io_ctl_check_generation(struct io_ctl *io_ctl, u64 generation)
 393{
 394	__le64 *gen;
 395
 396	/*
 397	 * Skip the crc area.  If we don't check crcs then we just have a 64bit
 398	 * chunk at the front of the first page.
 399	 */
 400	if (io_ctl->check_crcs) {
 401		io_ctl->cur += sizeof(u32) * io_ctl->num_pages;
 402		io_ctl->size -= sizeof(u64) +
 403			(sizeof(u32) * io_ctl->num_pages);
 404	} else {
 405		io_ctl->cur += sizeof(u64);
 406		io_ctl->size -= sizeof(u64) * 2;
 407	}
 408
 409	gen = io_ctl->cur;
 410	if (le64_to_cpu(*gen) != generation) {
 411		printk_ratelimited(KERN_ERR "btrfs: space cache generation "
 412				   "(%Lu) does not match inode (%Lu)\n", *gen,
 413				   generation);
 414		io_ctl_unmap_page(io_ctl);
 415		return -EIO;
 416	}
 417	io_ctl->cur += sizeof(u64);
 418	return 0;
 419}
 420
 421static void io_ctl_set_crc(struct io_ctl *io_ctl, int index)
 422{
 423	u32 *tmp;
 424	u32 crc = ~(u32)0;
 425	unsigned offset = 0;
 426
 427	if (!io_ctl->check_crcs) {
 428		io_ctl_unmap_page(io_ctl);
 429		return;
 430	}
 431
 432	if (index == 0)
 433		offset = sizeof(u32) * io_ctl->num_pages;
 434
 435	crc = btrfs_csum_data(io_ctl->root, io_ctl->orig + offset, crc,
 436			      PAGE_CACHE_SIZE - offset);
 437	btrfs_csum_final(crc, (char *)&crc);
 438	io_ctl_unmap_page(io_ctl);
 439	tmp = kmap(io_ctl->pages[0]);
 440	tmp += index;
 441	*tmp = crc;
 442	kunmap(io_ctl->pages[0]);
 443}
 444
 445static int io_ctl_check_crc(struct io_ctl *io_ctl, int index)
 446{
 447	u32 *tmp, val;
 448	u32 crc = ~(u32)0;
 449	unsigned offset = 0;
 450
 451	if (!io_ctl->check_crcs) {
 452		io_ctl_map_page(io_ctl, 0);
 453		return 0;
 454	}
 455
 456	if (index == 0)
 457		offset = sizeof(u32) * io_ctl->num_pages;
 458
 459	tmp = kmap(io_ctl->pages[0]);
 460	tmp += index;
 461	val = *tmp;
 462	kunmap(io_ctl->pages[0]);
 463
 464	io_ctl_map_page(io_ctl, 0);
 465	crc = btrfs_csum_data(io_ctl->root, io_ctl->orig + offset, crc,
 466			      PAGE_CACHE_SIZE - offset);
 467	btrfs_csum_final(crc, (char *)&crc);
 468	if (val != crc) {
 469		printk_ratelimited(KERN_ERR "btrfs: csum mismatch on free "
 470				   "space cache\n");
 471		io_ctl_unmap_page(io_ctl);
 472		return -EIO;
 473	}
 474
 475	return 0;
 476}
 477
 478static int io_ctl_add_entry(struct io_ctl *io_ctl, u64 offset, u64 bytes,
 479			    void *bitmap)
 480{
 481	struct btrfs_free_space_entry *entry;
 482
 483	if (!io_ctl->cur)
 484		return -ENOSPC;
 485
 486	entry = io_ctl->cur;
 487	entry->offset = cpu_to_le64(offset);
 488	entry->bytes = cpu_to_le64(bytes);
 489	entry->type = (bitmap) ? BTRFS_FREE_SPACE_BITMAP :
 490		BTRFS_FREE_SPACE_EXTENT;
 491	io_ctl->cur += sizeof(struct btrfs_free_space_entry);
 492	io_ctl->size -= sizeof(struct btrfs_free_space_entry);
 493
 494	if (io_ctl->size >= sizeof(struct btrfs_free_space_entry))
 495		return 0;
 496
 497	io_ctl_set_crc(io_ctl, io_ctl->index - 1);
 498
 499	/* No more pages to map */
 500	if (io_ctl->index >= io_ctl->num_pages)
 501		return 0;
 502
 503	/* map the next page */
 504	io_ctl_map_page(io_ctl, 1);
 505	return 0;
 506}
 507
 508static int io_ctl_add_bitmap(struct io_ctl *io_ctl, void *bitmap)
 509{
 510	if (!io_ctl->cur)
 511		return -ENOSPC;
 512
 513	/*
 514	 * If we aren't at the start of the current page, unmap this one and
 515	 * map the next one if there is any left.
 516	 */
 517	if (io_ctl->cur != io_ctl->orig) {
 518		io_ctl_set_crc(io_ctl, io_ctl->index - 1);
 519		if (io_ctl->index >= io_ctl->num_pages)
 520			return -ENOSPC;
 521		io_ctl_map_page(io_ctl, 0);
 522	}
 523
 524	memcpy(io_ctl->cur, bitmap, PAGE_CACHE_SIZE);
 525	io_ctl_set_crc(io_ctl, io_ctl->index - 1);
 526	if (io_ctl->index < io_ctl->num_pages)
 527		io_ctl_map_page(io_ctl, 0);
 528	return 0;
 529}
 530
 531static void io_ctl_zero_remaining_pages(struct io_ctl *io_ctl)
 532{
 533	/*
 534	 * If we're not on the boundary we know we've modified the page and we
 535	 * need to crc the page.
 536	 */
 537	if (io_ctl->cur != io_ctl->orig)
 538		io_ctl_set_crc(io_ctl, io_ctl->index - 1);
 539	else
 540		io_ctl_unmap_page(io_ctl);
 541
 542	while (io_ctl->index < io_ctl->num_pages) {
 543		io_ctl_map_page(io_ctl, 1);
 544		io_ctl_set_crc(io_ctl, io_ctl->index - 1);
 545	}
 546}
 547
 548static int io_ctl_read_entry(struct io_ctl *io_ctl,
 549			    struct btrfs_free_space *entry, u8 *type)
 550{
 551	struct btrfs_free_space_entry *e;
 552	int ret;
 553
 554	if (!io_ctl->cur) {
 555		ret = io_ctl_check_crc(io_ctl, io_ctl->index);
 556		if (ret)
 557			return ret;
 558	}
 559
 560	e = io_ctl->cur;
 561	entry->offset = le64_to_cpu(e->offset);
 562	entry->bytes = le64_to_cpu(e->bytes);
 563	*type = e->type;
 564	io_ctl->cur += sizeof(struct btrfs_free_space_entry);
 565	io_ctl->size -= sizeof(struct btrfs_free_space_entry);
 566
 567	if (io_ctl->size >= sizeof(struct btrfs_free_space_entry))
 568		return 0;
 569
 570	io_ctl_unmap_page(io_ctl);
 571
 572	return 0;
 573}
 574
 575static int io_ctl_read_bitmap(struct io_ctl *io_ctl,
 576			      struct btrfs_free_space *entry)
 577{
 578	int ret;
 579
 580	ret = io_ctl_check_crc(io_ctl, io_ctl->index);
 581	if (ret)
 582		return ret;
 583
 584	memcpy(entry->bitmap, io_ctl->cur, PAGE_CACHE_SIZE);
 585	io_ctl_unmap_page(io_ctl);
 586
 587	return 0;
 588}
 589
 590/*
 591 * Since we attach pinned extents after the fact we can have contiguous sections
 592 * of free space that are split up in entries.  This poses a problem with the
 593 * tree logging stuff since it could have allocated across what appears to be 2
 594 * entries since we would have merged the entries when adding the pinned extents
 595 * back to the free space cache.  So run through the space cache that we just
 596 * loaded and merge contiguous entries.  This will make the log replay stuff not
 597 * blow up and it will make for nicer allocator behavior.
 598 */
 599static void merge_space_tree(struct btrfs_free_space_ctl *ctl)
 600{
 601	struct btrfs_free_space *e, *prev = NULL;
 602	struct rb_node *n;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 603
 604again:
 605	spin_lock(&ctl->tree_lock);
 606	for (n = rb_first(&ctl->free_space_offset); n; n = rb_next(n)) {
 607		e = rb_entry(n, struct btrfs_free_space, offset_index);
 608		if (!prev)
 609			goto next;
 610		if (e->bitmap || prev->bitmap)
 611			goto next;
 612		if (prev->offset + prev->bytes == e->offset) {
 613			unlink_free_space(ctl, prev);
 614			unlink_free_space(ctl, e);
 615			prev->bytes += e->bytes;
 616			kmem_cache_free(btrfs_free_space_cachep, e);
 617			link_free_space(ctl, prev);
 618			prev = NULL;
 619			spin_unlock(&ctl->tree_lock);
 620			goto again;
 621		}
 622next:
 623		prev = e;
 624	}
 625	spin_unlock(&ctl->tree_lock);
 626}
 627
 628int __load_free_space_cache(struct btrfs_root *root, struct inode *inode,
 629			    struct btrfs_free_space_ctl *ctl,
 630			    struct btrfs_path *path, u64 offset)
 631{
 
 632	struct btrfs_free_space_header *header;
 633	struct extent_buffer *leaf;
 634	struct io_ctl io_ctl;
 635	struct btrfs_key key;
 636	struct btrfs_free_space *e, *n;
 637	struct list_head bitmaps;
 638	u64 num_entries;
 639	u64 num_bitmaps;
 640	u64 generation;
 641	u8 type;
 642	int ret = 0;
 643
 644	INIT_LIST_HEAD(&bitmaps);
 645
 646	/* Nothing in the space cache, goodbye */
 647	if (!i_size_read(inode))
 648		return 0;
 649
 650	key.objectid = BTRFS_FREE_SPACE_OBJECTID;
 651	key.offset = offset;
 652	key.type = 0;
 653
 654	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
 655	if (ret < 0)
 656		return 0;
 657	else if (ret > 0) {
 658		btrfs_release_path(path);
 659		return 0;
 660	}
 661
 662	ret = -1;
 663
 664	leaf = path->nodes[0];
 665	header = btrfs_item_ptr(leaf, path->slots[0],
 666				struct btrfs_free_space_header);
 667	num_entries = btrfs_free_space_entries(leaf, header);
 668	num_bitmaps = btrfs_free_space_bitmaps(leaf, header);
 669	generation = btrfs_free_space_generation(leaf, header);
 670	btrfs_release_path(path);
 671
 
 
 
 
 
 
 
 672	if (BTRFS_I(inode)->generation != generation) {
 673		printk(KERN_ERR "btrfs: free space inode generation (%llu) did"
 674		       " not match free space cache generation (%llu)\n",
 675		       (unsigned long long)BTRFS_I(inode)->generation,
 676		       (unsigned long long)generation);
 677		return 0;
 678	}
 679
 680	if (!num_entries)
 681		return 0;
 682
 683	ret = io_ctl_init(&io_ctl, inode, root);
 684	if (ret)
 685		return ret;
 686
 687	ret = readahead_cache(inode);
 688	if (ret)
 689		goto out;
 690
 691	ret = io_ctl_prepare_pages(&io_ctl, inode, 1);
 692	if (ret)
 693		goto out;
 694
 695	ret = io_ctl_check_crc(&io_ctl, 0);
 696	if (ret)
 697		goto free_cache;
 698
 699	ret = io_ctl_check_generation(&io_ctl, generation);
 700	if (ret)
 701		goto free_cache;
 702
 703	while (num_entries) {
 704		e = kmem_cache_zalloc(btrfs_free_space_cachep,
 705				      GFP_NOFS);
 706		if (!e)
 
 707			goto free_cache;
 
 708
 709		ret = io_ctl_read_entry(&io_ctl, e, &type);
 710		if (ret) {
 711			kmem_cache_free(btrfs_free_space_cachep, e);
 712			goto free_cache;
 713		}
 714
 715		if (!e->bytes) {
 
 716			kmem_cache_free(btrfs_free_space_cachep, e);
 717			goto free_cache;
 718		}
 719
 720		if (type == BTRFS_FREE_SPACE_EXTENT) {
 721			spin_lock(&ctl->tree_lock);
 722			ret = link_free_space(ctl, e);
 723			spin_unlock(&ctl->tree_lock);
 724			if (ret) {
 725				printk(KERN_ERR "Duplicate entries in "
 726				       "free space cache, dumping\n");
 727				kmem_cache_free(btrfs_free_space_cachep, e);
 728				goto free_cache;
 729			}
 730		} else {
 731			BUG_ON(!num_bitmaps);
 732			num_bitmaps--;
 733			e->bitmap = kzalloc(PAGE_CACHE_SIZE, GFP_NOFS);
 
 734			if (!e->bitmap) {
 
 735				kmem_cache_free(
 736					btrfs_free_space_cachep, e);
 737				goto free_cache;
 738			}
 739			spin_lock(&ctl->tree_lock);
 740			ret = link_free_space(ctl, e);
 741			ctl->total_bitmaps++;
 742			ctl->op->recalc_thresholds(ctl);
 743			spin_unlock(&ctl->tree_lock);
 744			if (ret) {
 745				printk(KERN_ERR "Duplicate entries in "
 746				       "free space cache, dumping\n");
 
 747				kmem_cache_free(btrfs_free_space_cachep, e);
 748				goto free_cache;
 749			}
 
 
 
 750			list_add_tail(&e->list, &bitmaps);
 751		}
 752
 753		num_entries--;
 754	}
 755
 756	io_ctl_unmap_page(&io_ctl);
 757
 758	/*
 759	 * We add the bitmaps at the end of the entries in order that
 760	 * the bitmap entries are added to the cache.
 761	 */
 762	list_for_each_entry_safe(e, n, &bitmaps, list) {
 763		list_del_init(&e->list);
 764		ret = io_ctl_read_bitmap(&io_ctl, e);
 765		if (ret)
 766			goto free_cache;
 767	}
 768
 769	io_ctl_drop_pages(&io_ctl);
 770	merge_space_tree(ctl);
 771	ret = 1;
 772out:
 773	io_ctl_free(&io_ctl);
 774	return ret;
 775free_cache:
 776	io_ctl_drop_pages(&io_ctl);
 
 
 777	__btrfs_remove_free_space_cache(ctl);
 
 778	goto out;
 779}
 780
 781int load_free_space_cache(struct btrfs_fs_info *fs_info,
 782			  struct btrfs_block_group_cache *block_group)
 783{
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 784	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
 785	struct btrfs_root *root = fs_info->tree_root;
 786	struct inode *inode;
 787	struct btrfs_path *path;
 788	int ret = 0;
 789	bool matched;
 790	u64 used = btrfs_block_group_used(&block_group->item);
 
 
 
 
 
 
 
 791
 792	/*
 793	 * If this block group has been marked to be cleared for one reason or
 794	 * another then we can't trust the on disk cache, so just return.
 795	 */
 796	spin_lock(&block_group->lock);
 797	if (block_group->disk_cache_state != BTRFS_DC_WRITTEN) {
 798		spin_unlock(&block_group->lock);
 799		return 0;
 800	}
 801	spin_unlock(&block_group->lock);
 802
 803	path = btrfs_alloc_path();
 804	if (!path)
 805		return 0;
 806	path->search_commit_root = 1;
 807	path->skip_locking = 1;
 808
 809	inode = lookup_free_space_inode(root, block_group, path);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 810	if (IS_ERR(inode)) {
 811		btrfs_free_path(path);
 812		return 0;
 813	}
 814
 815	/* We may have converted the inode and made the cache invalid. */
 816	spin_lock(&block_group->lock);
 817	if (block_group->disk_cache_state != BTRFS_DC_WRITTEN) {
 818		spin_unlock(&block_group->lock);
 819		btrfs_free_path(path);
 820		goto out;
 821	}
 822	spin_unlock(&block_group->lock);
 823
 824	ret = __load_free_space_cache(fs_info->tree_root, inode, ctl,
 825				      path, block_group->key.objectid);
 
 
 
 
 
 
 
 
 826	btrfs_free_path(path);
 827	if (ret <= 0)
 828		goto out;
 829
 830	spin_lock(&ctl->tree_lock);
 831	matched = (ctl->free_space == (block_group->key.offset - used -
 832				       block_group->bytes_super));
 833	spin_unlock(&ctl->tree_lock);
 834
 835	if (!matched) {
 836		__btrfs_remove_free_space_cache(ctl);
 837		printk(KERN_ERR "block group %llu has an wrong amount of free "
 838		       "space\n", block_group->key.objectid);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 839		ret = -1;
 840	}
 841out:
 842	if (ret < 0) {
 843		/* This cache is bogus, make sure it gets cleared */
 844		spin_lock(&block_group->lock);
 845		block_group->disk_cache_state = BTRFS_DC_CLEAR;
 846		spin_unlock(&block_group->lock);
 847		ret = 0;
 848
 849		printk(KERN_ERR "btrfs: failed to load free space cache "
 850		       "for block group %llu\n", block_group->key.objectid);
 
 851	}
 852
 
 
 
 853	iput(inode);
 854	return ret;
 855}
 856
 857/**
 858 * __btrfs_write_out_cache - write out cached info to an inode
 859 * @root - the root the inode belongs to
 860 * @ctl - the free space cache we are going to write out
 861 * @block_group - the block_group for this cache if it belongs to a block_group
 862 * @trans - the trans handle
 863 * @path - the path to use
 864 * @offset - the offset for the key we'll insert
 865 *
 866 * This function writes out a free space cache struct to disk for quick recovery
 867 * on mount.  This will return 0 if it was successfull in writing the cache out,
 868 * and -1 if it was not.
 869 */
 870int __btrfs_write_out_cache(struct btrfs_root *root, struct inode *inode,
 871			    struct btrfs_free_space_ctl *ctl,
 872			    struct btrfs_block_group_cache *block_group,
 873			    struct btrfs_trans_handle *trans,
 874			    struct btrfs_path *path, u64 offset)
 875{
 876	struct btrfs_free_space_header *header;
 877	struct extent_buffer *leaf;
 878	struct rb_node *node;
 879	struct list_head *pos, *n;
 880	struct extent_state *cached_state = NULL;
 881	struct btrfs_free_cluster *cluster = NULL;
 882	struct extent_io_tree *unpin = NULL;
 883	struct io_ctl io_ctl;
 884	struct list_head bitmap_list;
 885	struct btrfs_key key;
 886	u64 start, extent_start, extent_end, len;
 887	int entries = 0;
 888	int bitmaps = 0;
 889	int ret;
 890	int err = -1;
 891
 892	INIT_LIST_HEAD(&bitmap_list);
 893
 894	if (!i_size_read(inode))
 895		return -1;
 896
 897	ret = io_ctl_init(&io_ctl, inode, root);
 898	if (ret)
 899		return -1;
 900
 901	/* Get the cluster for this block_group if it exists */
 902	if (block_group && !list_empty(&block_group->cluster_list))
 903		cluster = list_entry(block_group->cluster_list.next,
 904				     struct btrfs_free_cluster,
 905				     block_group_list);
 
 906
 907	/* Lock all pages first so we can lock the extent safely. */
 908	io_ctl_prepare_pages(&io_ctl, inode, 0);
 909
 910	lock_extent_bits(&BTRFS_I(inode)->io_tree, 0, i_size_read(inode) - 1,
 911			 0, &cached_state);
 912
 913	node = rb_first(&ctl->free_space_offset);
 914	if (!node && cluster) {
 
 
 915		node = rb_first(&cluster->root);
 916		cluster = NULL;
 917	}
 918
 919	/* Make sure we can fit our crcs into the first page */
 920	if (io_ctl.check_crcs &&
 921	    (io_ctl.num_pages * sizeof(u32)) >= PAGE_CACHE_SIZE) {
 922		WARN_ON(1);
 923		goto out_nospc;
 924	}
 925
 926	io_ctl_set_generation(&io_ctl, trans->transid);
 927
 928	/* Write out the extent entries */
 929	while (node) {
 930		struct btrfs_free_space *e;
 931
 932		e = rb_entry(node, struct btrfs_free_space, offset_index);
 933		entries++;
 934
 935		ret = io_ctl_add_entry(&io_ctl, e->offset, e->bytes,
 936				       e->bitmap);
 937		if (ret)
 938			goto out_nospc;
 939
 940		if (e->bitmap) {
 941			list_add_tail(&e->list, &bitmap_list);
 942			bitmaps++;
 943		}
 944		node = rb_next(node);
 945		if (!node && cluster) {
 946			node = rb_first(&cluster->root);
 
 
 947			cluster = NULL;
 948		}
 949	}
 
 
 
 
 950
 951	/*
 952	 * We want to add any pinned extents to our free space cache
 953	 * so we don't leak the space
 
 
 954	 */
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 955
 956	/*
 
 
 
 957	 * We shouldn't have switched the pinned extents yet so this is the
 958	 * right one
 959	 */
 960	unpin = root->fs_info->pinned_extents;
 961
 962	if (block_group)
 963		start = block_group->key.objectid;
 964
 965	while (block_group && (start < block_group->key.objectid +
 966			       block_group->key.offset)) {
 967		ret = find_first_extent_bit(unpin, start,
 968					    &extent_start, &extent_end,
 969					    EXTENT_DIRTY);
 970		if (ret) {
 971			ret = 0;
 972			break;
 973		}
 974
 975		/* This pinned extent is out of our range */
 976		if (extent_start >= block_group->key.objectid +
 977		    block_group->key.offset)
 978			break;
 979
 980		extent_start = max(extent_start, start);
 981		extent_end = min(block_group->key.objectid +
 982				 block_group->key.offset, extent_end + 1);
 983		len = extent_end - extent_start;
 984
 985		entries++;
 986		ret = io_ctl_add_entry(&io_ctl, extent_start, len, NULL);
 987		if (ret)
 988			goto out_nospc;
 989
 990		start = extent_end;
 991	}
 992
 
 
 
 
 
 
 
 
 
 993	/* Write out the bitmaps */
 994	list_for_each_safe(pos, n, &bitmap_list) {
 995		struct btrfs_free_space *entry =
 996			list_entry(pos, struct btrfs_free_space, list);
 997
 998		ret = io_ctl_add_bitmap(&io_ctl, entry->bitmap);
 999		if (ret)
1000			goto out_nospc;
1001		list_del_init(&entry->list);
1002	}
1003
1004	/* Zero out the rest of the pages just to make sure */
1005	io_ctl_zero_remaining_pages(&io_ctl);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1006
1007	ret = btrfs_dirty_pages(root, inode, io_ctl.pages, io_ctl.num_pages,
1008				0, i_size_read(inode), &cached_state);
1009	io_ctl_drop_pages(&io_ctl);
1010	unlock_extent_cached(&BTRFS_I(inode)->io_tree, 0,
1011			     i_size_read(inode) - 1, &cached_state, GFP_NOFS);
1012
 
 
1013	if (ret)
1014		goto out;
1015
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1016
1017	btrfs_wait_ordered_range(inode, 0, (u64)-1);
 
1018
1019	key.objectid = BTRFS_FREE_SPACE_OBJECTID;
1020	key.offset = offset;
1021	key.type = 0;
 
 
 
 
 
 
1022
1023	ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
1024	if (ret < 0) {
1025		clear_extent_bit(&BTRFS_I(inode)->io_tree, 0, inode->i_size - 1,
1026				 EXTENT_DIRTY | EXTENT_DELALLOC, 0, 0, NULL,
1027				 GFP_NOFS);
1028		goto out;
1029	}
1030	leaf = path->nodes[0];
1031	if (ret > 0) {
1032		struct btrfs_key found_key;
1033		BUG_ON(!path->slots[0]);
1034		path->slots[0]--;
1035		btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
1036		if (found_key.objectid != BTRFS_FREE_SPACE_OBJECTID ||
1037		    found_key.offset != offset) {
1038			clear_extent_bit(&BTRFS_I(inode)->io_tree, 0,
1039					 inode->i_size - 1,
1040					 EXTENT_DIRTY | EXTENT_DELALLOC, 0, 0,
1041					 NULL, GFP_NOFS);
1042			btrfs_release_path(path);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1043			goto out;
1044		}
 
1045	}
1046
1047	BTRFS_I(inode)->generation = trans->transid;
1048	header = btrfs_item_ptr(leaf, path->slots[0],
1049				struct btrfs_free_space_header);
1050	btrfs_set_free_space_entries(leaf, header, entries);
1051	btrfs_set_free_space_bitmaps(leaf, header, bitmaps);
1052	btrfs_set_free_space_generation(leaf, header, trans->transid);
1053	btrfs_mark_buffer_dirty(leaf);
1054	btrfs_release_path(path);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1055
1056	err = 0;
1057out:
1058	io_ctl_free(&io_ctl);
1059	if (err) {
 
1060		invalidate_inode_pages2(inode->i_mapping);
1061		BTRFS_I(inode)->generation = 0;
1062	}
1063	btrfs_update_inode(trans, root, inode);
1064	return err;
1065
1066out_nospc:
1067	list_for_each_safe(pos, n, &bitmap_list) {
1068		struct btrfs_free_space *entry =
1069			list_entry(pos, struct btrfs_free_space, list);
1070		list_del_init(&entry->list);
1071	}
1072	io_ctl_drop_pages(&io_ctl);
1073	unlock_extent_cached(&BTRFS_I(inode)->io_tree, 0,
1074			     i_size_read(inode) - 1, &cached_state, GFP_NOFS);
1075	goto out;
1076}
1077
1078int btrfs_write_out_cache(struct btrfs_root *root,
1079			  struct btrfs_trans_handle *trans,
1080			  struct btrfs_block_group_cache *block_group,
1081			  struct btrfs_path *path)
1082{
 
1083	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
1084	struct inode *inode;
1085	int ret = 0;
1086
1087	root = root->fs_info->tree_root;
1088
1089	spin_lock(&block_group->lock);
1090	if (block_group->disk_cache_state < BTRFS_DC_SETUP) {
1091		spin_unlock(&block_group->lock);
1092		return 0;
1093	}
1094	spin_unlock(&block_group->lock);
1095
1096	inode = lookup_free_space_inode(root, block_group, path);
1097	if (IS_ERR(inode))
1098		return 0;
1099
1100	ret = __btrfs_write_out_cache(root, inode, ctl, block_group, trans,
1101				      path, block_group->key.objectid);
1102	if (ret) {
 
 
 
1103		spin_lock(&block_group->lock);
1104		block_group->disk_cache_state = BTRFS_DC_ERROR;
1105		spin_unlock(&block_group->lock);
1106		ret = 0;
1107#ifdef DEBUG
1108		printk(KERN_ERR "btrfs: failed to write free space cache "
1109		       "for block group %llu\n", block_group->key.objectid);
1110#endif
1111	}
1112
1113	iput(inode);
 
 
 
 
1114	return ret;
1115}
1116
1117static inline unsigned long offset_to_bit(u64 bitmap_start, u32 unit,
1118					  u64 offset)
1119{
1120	BUG_ON(offset < bitmap_start);
1121	offset -= bitmap_start;
1122	return (unsigned long)(div_u64(offset, unit));
1123}
1124
1125static inline unsigned long bytes_to_bits(u64 bytes, u32 unit)
1126{
1127	return (unsigned long)(div_u64(bytes, unit));
1128}
1129
1130static inline u64 offset_to_bitmap(struct btrfs_free_space_ctl *ctl,
1131				   u64 offset)
1132{
1133	u64 bitmap_start;
1134	u64 bytes_per_bitmap;
1135
1136	bytes_per_bitmap = BITS_PER_BITMAP * ctl->unit;
1137	bitmap_start = offset - ctl->start;
1138	bitmap_start = div64_u64(bitmap_start, bytes_per_bitmap);
1139	bitmap_start *= bytes_per_bitmap;
1140	bitmap_start += ctl->start;
1141
1142	return bitmap_start;
1143}
1144
1145static int tree_insert_offset(struct rb_root *root, u64 offset,
1146			      struct rb_node *node, int bitmap)
 
1147{
1148	struct rb_node **p = &root->rb_node;
 
1149	struct rb_node *parent = NULL;
1150	struct btrfs_free_space *info;
 
 
 
 
 
 
 
 
 
 
1151
1152	while (*p) {
 
 
1153		parent = *p;
1154		info = rb_entry(parent, struct btrfs_free_space, offset_index);
1155
1156		if (offset < info->offset) {
1157			p = &(*p)->rb_left;
1158		} else if (offset > info->offset) {
1159			p = &(*p)->rb_right;
1160		} else {
1161			/*
1162			 * we could have a bitmap entry and an extent entry
1163			 * share the same offset.  If this is the case, we want
1164			 * the extent entry to always be found first if we do a
1165			 * linear search through the tree, since we want to have
1166			 * the quickest allocation time, and allocating from an
1167			 * extent is faster than allocating from a bitmap.  So
1168			 * if we're inserting a bitmap and we find an entry at
1169			 * this offset, we want to go right, or after this entry
1170			 * logically.  If we are inserting an extent and we've
1171			 * found a bitmap, we want to go left, or before
1172			 * logically.
1173			 */
1174			if (bitmap) {
1175				if (info->bitmap) {
1176					WARN_ON_ONCE(1);
1177					return -EEXIST;
1178				}
1179				p = &(*p)->rb_right;
1180			} else {
1181				if (!info->bitmap) {
1182					WARN_ON_ONCE(1);
1183					return -EEXIST;
1184				}
1185				p = &(*p)->rb_left;
1186			}
1187		}
1188	}
1189
1190	rb_link_node(node, parent, p);
1191	rb_insert_color(node, root);
1192
1193	return 0;
1194}
1195
1196/*
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1197 * searches the tree for the given offset.
1198 *
1199 * fuzzy - If this is set, then we are trying to make an allocation, and we just
1200 * want a section that has at least bytes size and comes at or after the given
1201 * offset.
1202 */
1203static struct btrfs_free_space *
1204tree_search_offset(struct btrfs_free_space_ctl *ctl,
1205		   u64 offset, int bitmap_only, int fuzzy)
1206{
1207	struct rb_node *n = ctl->free_space_offset.rb_node;
1208	struct btrfs_free_space *entry, *prev = NULL;
 
 
1209
1210	/* find entry that is closest to the 'offset' */
1211	while (1) {
1212		if (!n) {
1213			entry = NULL;
1214			break;
1215		}
1216
1217		entry = rb_entry(n, struct btrfs_free_space, offset_index);
1218		prev = entry;
1219
1220		if (offset < entry->offset)
1221			n = n->rb_left;
1222		else if (offset > entry->offset)
1223			n = n->rb_right;
1224		else
1225			break;
 
 
1226	}
1227
1228	if (bitmap_only) {
1229		if (!entry)
1230			return NULL;
1231		if (entry->bitmap)
1232			return entry;
1233
1234		/*
1235		 * bitmap entry and extent entry may share same offset,
1236		 * in that case, bitmap entry comes after extent entry.
1237		 */
1238		n = rb_next(n);
1239		if (!n)
1240			return NULL;
1241		entry = rb_entry(n, struct btrfs_free_space, offset_index);
1242		if (entry->offset != offset)
1243			return NULL;
1244
1245		WARN_ON(!entry->bitmap);
1246		return entry;
1247	} else if (entry) {
1248		if (entry->bitmap) {
1249			/*
1250			 * if previous extent entry covers the offset,
1251			 * we should return it instead of the bitmap entry
1252			 */
1253			n = &entry->offset_index;
1254			while (1) {
1255				n = rb_prev(n);
1256				if (!n)
1257					break;
1258				prev = rb_entry(n, struct btrfs_free_space,
1259						offset_index);
1260				if (!prev->bitmap) {
1261					if (prev->offset + prev->bytes > offset)
1262						entry = prev;
1263					break;
1264				}
1265			}
1266		}
1267		return entry;
1268	}
1269
1270	if (!prev)
1271		return NULL;
1272
1273	/* find last entry before the 'offset' */
1274	entry = prev;
1275	if (entry->offset > offset) {
1276		n = rb_prev(&entry->offset_index);
1277		if (n) {
1278			entry = rb_entry(n, struct btrfs_free_space,
1279					offset_index);
1280			BUG_ON(entry->offset > offset);
1281		} else {
1282			if (fuzzy)
1283				return entry;
1284			else
1285				return NULL;
1286		}
1287	}
1288
1289	if (entry->bitmap) {
1290		n = &entry->offset_index;
1291		while (1) {
1292			n = rb_prev(n);
1293			if (!n)
1294				break;
1295			prev = rb_entry(n, struct btrfs_free_space,
1296					offset_index);
1297			if (!prev->bitmap) {
1298				if (prev->offset + prev->bytes > offset)
1299					return prev;
1300				break;
1301			}
1302		}
1303		if (entry->offset + BITS_PER_BITMAP * ctl->unit > offset)
1304			return entry;
1305	} else if (entry->offset + entry->bytes > offset)
1306		return entry;
1307
1308	if (!fuzzy)
1309		return NULL;
1310
1311	while (1) {
 
 
 
 
1312		if (entry->bitmap) {
1313			if (entry->offset + BITS_PER_BITMAP *
1314			    ctl->unit > offset)
1315				break;
1316		} else {
1317			if (entry->offset + entry->bytes > offset)
1318				break;
1319		}
1320
1321		n = rb_next(&entry->offset_index);
1322		if (!n)
1323			return NULL;
1324		entry = rb_entry(n, struct btrfs_free_space, offset_index);
1325	}
1326	return entry;
1327}
1328
1329static inline void
1330__unlink_free_space(struct btrfs_free_space_ctl *ctl,
1331		    struct btrfs_free_space *info)
1332{
 
 
1333	rb_erase(&info->offset_index, &ctl->free_space_offset);
 
1334	ctl->free_extents--;
1335}
1336
1337static void unlink_free_space(struct btrfs_free_space_ctl *ctl,
1338			      struct btrfs_free_space *info)
1339{
1340	__unlink_free_space(ctl, info);
1341	ctl->free_space -= info->bytes;
 
 
1342}
1343
1344static int link_free_space(struct btrfs_free_space_ctl *ctl,
1345			   struct btrfs_free_space *info)
1346{
1347	int ret = 0;
1348
1349	BUG_ON(!info->bitmap && !info->bytes);
1350	ret = tree_insert_offset(&ctl->free_space_offset, info->offset,
1351				 &info->offset_index, (info->bitmap != NULL));
 
1352	if (ret)
1353		return ret;
1354
 
 
 
 
 
 
 
1355	ctl->free_space += info->bytes;
1356	ctl->free_extents++;
1357	return ret;
1358}
1359
1360static void recalculate_thresholds(struct btrfs_free_space_ctl *ctl)
 
1361{
1362	struct btrfs_block_group_cache *block_group = ctl->private;
1363	u64 max_bytes;
1364	u64 bitmap_bytes;
1365	u64 extent_bytes;
1366	u64 size = block_group->key.offset;
1367	u64 bytes_per_bg = BITS_PER_BITMAP * block_group->sectorsize;
1368	int max_bitmaps = div64_u64(size + bytes_per_bg - 1, bytes_per_bg);
1369
1370	BUG_ON(ctl->total_bitmaps > max_bitmaps);
1371
1372	/*
1373	 * The goal is to keep the total amount of memory used per 1gb of space
1374	 * at or below 32k, so we need to adjust how much memory we allow to be
1375	 * used by extent based free space tracking
1376	 */
1377	if (size < 1024 * 1024 * 1024)
1378		max_bytes = MAX_CACHE_BYTES_PER_GIG;
1379	else
1380		max_bytes = MAX_CACHE_BYTES_PER_GIG *
1381			div64_u64(size, 1024 * 1024 * 1024);
1382
1383	/*
1384	 * we want to account for 1 more bitmap than what we have so we can make
1385	 * sure we don't go over our overall goal of MAX_CACHE_BYTES_PER_GIG as
1386	 * we add more bitmaps.
1387	 */
1388	bitmap_bytes = (ctl->total_bitmaps + 1) * PAGE_CACHE_SIZE;
1389
1390	if (bitmap_bytes >= max_bytes) {
1391		ctl->extents_thresh = 0;
1392		return;
1393	}
1394
1395	/*
1396	 * we want the extent entry threshold to always be at most 1/2 the maxw
1397	 * bytes we can have, or whatever is less than that.
1398	 */
1399	extent_bytes = max_bytes - bitmap_bytes;
1400	extent_bytes = min_t(u64, extent_bytes, div64_u64(max_bytes, 2));
1401
1402	ctl->extents_thresh =
1403		div64_u64(extent_bytes, (sizeof(struct btrfs_free_space)));
1404}
1405
1406static inline void __bitmap_clear_bits(struct btrfs_free_space_ctl *ctl,
1407				       struct btrfs_free_space *info,
1408				       u64 offset, u64 bytes)
1409{
1410	unsigned long start, count;
 
1411
1412	start = offset_to_bit(info->offset, ctl->unit, offset);
1413	count = bytes_to_bits(bytes, ctl->unit);
1414	BUG_ON(start + count > BITS_PER_BITMAP);
 
1415
1416	bitmap_clear(info->bitmap, start, count);
1417
1418	info->bytes -= bytes;
1419}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1420
1421static void bitmap_clear_bits(struct btrfs_free_space_ctl *ctl,
1422			      struct btrfs_free_space *info, u64 offset,
1423			      u64 bytes)
1424{
1425	__bitmap_clear_bits(ctl, info, offset, bytes);
1426	ctl->free_space -= bytes;
1427}
1428
1429static void bitmap_set_bits(struct btrfs_free_space_ctl *ctl,
1430			    struct btrfs_free_space *info, u64 offset,
1431			    u64 bytes)
1432{
1433	unsigned long start, count;
 
1434
1435	start = offset_to_bit(info->offset, ctl->unit, offset);
1436	count = bytes_to_bits(bytes, ctl->unit);
1437	BUG_ON(start + count > BITS_PER_BITMAP);
 
1438
1439	bitmap_set(info->bitmap, start, count);
1440
 
 
 
 
 
1441	info->bytes += bytes;
1442	ctl->free_space += bytes;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1443}
1444
 
 
 
 
1445static int search_bitmap(struct btrfs_free_space_ctl *ctl,
1446			 struct btrfs_free_space *bitmap_info, u64 *offset,
1447			 u64 *bytes)
1448{
1449	unsigned long found_bits = 0;
 
1450	unsigned long bits, i;
1451	unsigned long next_zero;
 
 
 
 
 
 
 
 
 
 
 
 
1452
1453	i = offset_to_bit(bitmap_info->offset, ctl->unit,
1454			  max_t(u64, *offset, bitmap_info->offset));
1455	bits = bytes_to_bits(*bytes, ctl->unit);
1456
1457	for (i = find_next_bit(bitmap_info->bitmap, BITS_PER_BITMAP, i);
1458	     i < BITS_PER_BITMAP;
1459	     i = find_next_bit(bitmap_info->bitmap, BITS_PER_BITMAP, i + 1)) {
 
 
1460		next_zero = find_next_zero_bit(bitmap_info->bitmap,
1461					       BITS_PER_BITMAP, i);
1462		if ((next_zero - i) >= bits) {
1463			found_bits = next_zero - i;
 
1464			break;
 
 
1465		}
1466		i = next_zero;
1467	}
1468
1469	if (found_bits) {
1470		*offset = (u64)(i * ctl->unit) + bitmap_info->offset;
1471		*bytes = (u64)(found_bits) * ctl->unit;
1472		return 0;
1473	}
1474
 
 
 
1475	return -1;
1476}
1477
 
1478static struct btrfs_free_space *
1479find_free_space(struct btrfs_free_space_ctl *ctl, u64 *offset, u64 *bytes)
 
1480{
1481	struct btrfs_free_space *entry;
1482	struct rb_node *node;
 
 
1483	int ret;
1484
1485	if (!ctl->free_space_offset.rb_node)
1486		return NULL;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1487
1488	entry = tree_search_offset(ctl, offset_to_bitmap(ctl, *offset), 0, 1);
1489	if (!entry)
1490		return NULL;
 
 
 
 
 
 
 
 
 
1491
1492	for (node = &entry->offset_index; node; node = rb_next(node)) {
1493		entry = rb_entry(node, struct btrfs_free_space, offset_index);
1494		if (entry->bytes < *bytes)
 
 
 
 
 
 
 
1495			continue;
 
1496
1497		if (entry->bitmap) {
1498			ret = search_bitmap(ctl, entry, offset, bytes);
1499			if (!ret)
 
 
 
 
 
1500				return entry;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1501			continue;
1502		}
1503
1504		*offset = entry->offset;
1505		*bytes = entry->bytes;
1506		return entry;
1507	}
1508
1509	return NULL;
1510}
1511
1512static void add_new_bitmap(struct btrfs_free_space_ctl *ctl,
1513			   struct btrfs_free_space *info, u64 offset)
1514{
1515	info->offset = offset_to_bitmap(ctl, offset);
1516	info->bytes = 0;
 
1517	INIT_LIST_HEAD(&info->list);
1518	link_free_space(ctl, info);
1519	ctl->total_bitmaps++;
1520
1521	ctl->op->recalc_thresholds(ctl);
1522}
1523
1524static void free_bitmap(struct btrfs_free_space_ctl *ctl,
1525			struct btrfs_free_space *bitmap_info)
1526{
1527	unlink_free_space(ctl, bitmap_info);
1528	kfree(bitmap_info->bitmap);
 
 
 
 
 
 
 
 
 
 
 
 
1529	kmem_cache_free(btrfs_free_space_cachep, bitmap_info);
1530	ctl->total_bitmaps--;
1531	ctl->op->recalc_thresholds(ctl);
1532}
1533
1534static noinline int remove_from_bitmap(struct btrfs_free_space_ctl *ctl,
1535			      struct btrfs_free_space *bitmap_info,
1536			      u64 *offset, u64 *bytes)
1537{
1538	u64 end;
1539	u64 search_start, search_bytes;
1540	int ret;
1541
1542again:
1543	end = bitmap_info->offset + (u64)(BITS_PER_BITMAP * ctl->unit) - 1;
1544
1545	/*
1546	 * We need to search for bits in this bitmap.  We could only cover some
1547	 * of the extent in this bitmap thanks to how we add space, so we need
1548	 * to search for as much as it as we can and clear that amount, and then
1549	 * go searching for the next bit.
1550	 */
1551	search_start = *offset;
1552	search_bytes = ctl->unit;
1553	search_bytes = min(search_bytes, end - search_start + 1);
1554	ret = search_bitmap(ctl, bitmap_info, &search_start, &search_bytes);
1555	BUG_ON(ret < 0 || search_start != *offset);
 
 
1556
1557	/* We may have found more bits than what we need */
1558	search_bytes = min(search_bytes, *bytes);
1559
1560	/* Cannot clear past the end of the bitmap */
1561	search_bytes = min(search_bytes, end - search_start + 1);
1562
1563	bitmap_clear_bits(ctl, bitmap_info, search_start, search_bytes);
1564	*offset += search_bytes;
1565	*bytes -= search_bytes;
1566
1567	if (*bytes) {
1568		struct rb_node *next = rb_next(&bitmap_info->offset_index);
1569		if (!bitmap_info->bytes)
1570			free_bitmap(ctl, bitmap_info);
1571
1572		/*
1573		 * no entry after this bitmap, but we still have bytes to
1574		 * remove, so something has gone wrong.
1575		 */
1576		if (!next)
1577			return -EINVAL;
1578
1579		bitmap_info = rb_entry(next, struct btrfs_free_space,
1580				       offset_index);
1581
1582		/*
1583		 * if the next entry isn't a bitmap we need to return to let the
1584		 * extent stuff do its work.
1585		 */
1586		if (!bitmap_info->bitmap)
1587			return -EAGAIN;
1588
1589		/*
1590		 * Ok the next item is a bitmap, but it may not actually hold
1591		 * the information for the rest of this free space stuff, so
1592		 * look for it, and if we don't find it return so we can try
1593		 * everything over again.
1594		 */
1595		search_start = *offset;
1596		search_bytes = ctl->unit;
1597		ret = search_bitmap(ctl, bitmap_info, &search_start,
1598				    &search_bytes);
1599		if (ret < 0 || search_start != *offset)
1600			return -EAGAIN;
1601
1602		goto again;
1603	} else if (!bitmap_info->bytes)
1604		free_bitmap(ctl, bitmap_info);
1605
1606	return 0;
1607}
1608
1609static u64 add_bytes_to_bitmap(struct btrfs_free_space_ctl *ctl,
1610			       struct btrfs_free_space *info, u64 offset,
1611			       u64 bytes)
1612{
1613	u64 bytes_to_set = 0;
1614	u64 end;
1615
 
 
 
 
 
 
 
 
 
 
 
 
 
1616	end = info->offset + (u64)(BITS_PER_BITMAP * ctl->unit);
1617
1618	bytes_to_set = min(end - offset, bytes);
1619
1620	bitmap_set_bits(ctl, info, offset, bytes_to_set);
1621
1622	return bytes_to_set;
1623
1624}
1625
1626static bool use_bitmap(struct btrfs_free_space_ctl *ctl,
1627		      struct btrfs_free_space *info)
1628{
1629	struct btrfs_block_group_cache *block_group = ctl->private;
 
 
 
 
 
 
 
 
 
 
 
1630
1631	/*
1632	 * If we are below the extents threshold then we can add this as an
1633	 * extent, and don't have to deal with the bitmap
1634	 */
1635	if (ctl->free_extents < ctl->extents_thresh) {
1636		/*
1637		 * If this block group has some small extents we don't want to
1638		 * use up all of our free slots in the cache with them, we want
1639		 * to reserve them to larger extents, however if we have plent
1640		 * of cache left then go ahead an dadd them, no sense in adding
1641		 * the overhead of a bitmap if we don't have to.
1642		 */
1643		if (info->bytes <= block_group->sectorsize * 4) {
1644			if (ctl->free_extents * 2 <= ctl->extents_thresh)
1645				return false;
1646		} else {
1647			return false;
1648		}
1649	}
1650
1651	/*
1652	 * some block groups are so tiny they can't be enveloped by a bitmap, so
1653	 * don't even bother to create a bitmap for this
 
 
 
 
1654	 */
1655	if (BITS_PER_BITMAP * block_group->sectorsize >
1656	    block_group->key.offset)
1657		return false;
1658
1659	return true;
1660}
1661
1662static struct btrfs_free_space_op free_space_op = {
1663	.recalc_thresholds	= recalculate_thresholds,
1664	.use_bitmap		= use_bitmap,
1665};
1666
1667static int insert_into_bitmap(struct btrfs_free_space_ctl *ctl,
1668			      struct btrfs_free_space *info)
1669{
1670	struct btrfs_free_space *bitmap_info;
1671	struct btrfs_block_group_cache *block_group = NULL;
1672	int added = 0;
1673	u64 bytes, offset, bytes_added;
 
1674	int ret;
1675
1676	bytes = info->bytes;
1677	offset = info->offset;
 
1678
1679	if (!ctl->op->use_bitmap(ctl, info))
1680		return 0;
1681
1682	if (ctl->op == &free_space_op)
1683		block_group = ctl->private;
1684again:
1685	/*
1686	 * Since we link bitmaps right into the cluster we need to see if we
1687	 * have a cluster here, and if so and it has our bitmap we need to add
1688	 * the free space to that bitmap.
1689	 */
1690	if (block_group && !list_empty(&block_group->cluster_list)) {
1691		struct btrfs_free_cluster *cluster;
1692		struct rb_node *node;
1693		struct btrfs_free_space *entry;
1694
1695		cluster = list_entry(block_group->cluster_list.next,
1696				     struct btrfs_free_cluster,
1697				     block_group_list);
1698		spin_lock(&cluster->lock);
1699		node = rb_first(&cluster->root);
1700		if (!node) {
1701			spin_unlock(&cluster->lock);
1702			goto no_cluster_bitmap;
1703		}
1704
1705		entry = rb_entry(node, struct btrfs_free_space, offset_index);
1706		if (!entry->bitmap) {
1707			spin_unlock(&cluster->lock);
1708			goto no_cluster_bitmap;
1709		}
1710
1711		if (entry->offset == offset_to_bitmap(ctl, offset)) {
1712			bytes_added = add_bytes_to_bitmap(ctl, entry,
1713							  offset, bytes);
1714			bytes -= bytes_added;
1715			offset += bytes_added;
1716		}
1717		spin_unlock(&cluster->lock);
1718		if (!bytes) {
1719			ret = 1;
1720			goto out;
1721		}
1722	}
1723
1724no_cluster_bitmap:
1725	bitmap_info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
1726					 1, 0);
1727	if (!bitmap_info) {
1728		BUG_ON(added);
1729		goto new_bitmap;
1730	}
1731
1732	bytes_added = add_bytes_to_bitmap(ctl, bitmap_info, offset, bytes);
 
1733	bytes -= bytes_added;
1734	offset += bytes_added;
1735	added = 0;
1736
1737	if (!bytes) {
1738		ret = 1;
1739		goto out;
1740	} else
1741		goto again;
1742
1743new_bitmap:
1744	if (info && info->bitmap) {
1745		add_new_bitmap(ctl, info, offset);
1746		added = 1;
1747		info = NULL;
1748		goto again;
1749	} else {
1750		spin_unlock(&ctl->tree_lock);
1751
1752		/* no pre-allocated info, allocate a new one */
1753		if (!info) {
1754			info = kmem_cache_zalloc(btrfs_free_space_cachep,
1755						 GFP_NOFS);
1756			if (!info) {
1757				spin_lock(&ctl->tree_lock);
1758				ret = -ENOMEM;
1759				goto out;
1760			}
1761		}
1762
1763		/* allocate the bitmap */
1764		info->bitmap = kzalloc(PAGE_CACHE_SIZE, GFP_NOFS);
 
 
1765		spin_lock(&ctl->tree_lock);
1766		if (!info->bitmap) {
1767			ret = -ENOMEM;
1768			goto out;
1769		}
1770		goto again;
1771	}
1772
1773out:
1774	if (info) {
1775		if (info->bitmap)
1776			kfree(info->bitmap);
 
1777		kmem_cache_free(btrfs_free_space_cachep, info);
1778	}
1779
1780	return ret;
1781}
1782
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1783static bool try_merge_free_space(struct btrfs_free_space_ctl *ctl,
1784			  struct btrfs_free_space *info, bool update_stat)
1785{
1786	struct btrfs_free_space *left_info;
1787	struct btrfs_free_space *right_info;
1788	bool merged = false;
1789	u64 offset = info->offset;
1790	u64 bytes = info->bytes;
 
 
1791
1792	/*
1793	 * first we want to see if there is free space adjacent to the range we
1794	 * are adding, if there is remove that struct and add a new one to
1795	 * cover the entire range
1796	 */
1797	right_info = tree_search_offset(ctl, offset + bytes, 0, 0);
1798	if (right_info && rb_prev(&right_info->offset_index))
1799		left_info = rb_entry(rb_prev(&right_info->offset_index),
1800				     struct btrfs_free_space, offset_index);
1801	else
 
 
1802		left_info = tree_search_offset(ctl, offset - 1, 0, 0);
1803
1804	if (right_info && !right_info->bitmap) {
1805		if (update_stat)
1806			unlink_free_space(ctl, right_info);
1807		else
1808			__unlink_free_space(ctl, right_info);
1809		info->bytes += right_info->bytes;
1810		kmem_cache_free(btrfs_free_space_cachep, right_info);
1811		merged = true;
1812	}
1813
 
1814	if (left_info && !left_info->bitmap &&
1815	    left_info->offset + left_info->bytes == offset) {
1816		if (update_stat)
1817			unlink_free_space(ctl, left_info);
1818		else
1819			__unlink_free_space(ctl, left_info);
1820		info->offset = left_info->offset;
1821		info->bytes += left_info->bytes;
1822		kmem_cache_free(btrfs_free_space_cachep, left_info);
1823		merged = true;
1824	}
1825
1826	return merged;
1827}
1828
1829int __btrfs_add_free_space(struct btrfs_free_space_ctl *ctl,
1830			   u64 offset, u64 bytes)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1831{
 
 
1832	struct btrfs_free_space *info;
1833	int ret = 0;
 
 
 
1834
1835	info = kmem_cache_zalloc(btrfs_free_space_cachep, GFP_NOFS);
1836	if (!info)
1837		return -ENOMEM;
1838
1839	info->offset = offset;
1840	info->bytes = bytes;
 
 
 
1841
1842	spin_lock(&ctl->tree_lock);
1843
1844	if (try_merge_free_space(ctl, info, true))
1845		goto link;
1846
1847	/*
1848	 * There was no extent directly to the left or right of this new
1849	 * extent then we know we're going to have to allocate a new extent, so
1850	 * before we do that see if we need to drop this into a bitmap
1851	 */
1852	ret = insert_into_bitmap(ctl, info);
1853	if (ret < 0) {
1854		goto out;
1855	} else if (ret) {
1856		ret = 0;
1857		goto out;
1858	}
1859link:
 
 
 
 
 
 
 
 
 
 
1860	ret = link_free_space(ctl, info);
1861	if (ret)
1862		kmem_cache_free(btrfs_free_space_cachep, info);
1863out:
 
1864	spin_unlock(&ctl->tree_lock);
1865
1866	if (ret) {
1867		printk(KERN_CRIT "btrfs: unable to add free space :%d\n", ret);
1868		BUG_ON(ret == -EEXIST);
 
 
 
 
 
1869	}
1870
1871	return ret;
1872}
1873
1874int btrfs_remove_free_space(struct btrfs_block_group_cache *block_group,
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1875			    u64 offset, u64 bytes)
1876{
1877	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
1878	struct btrfs_free_space *info;
1879	int ret = 0;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1880
1881	spin_lock(&ctl->tree_lock);
1882
1883again:
 
1884	if (!bytes)
1885		goto out_lock;
1886
1887	info = tree_search_offset(ctl, offset, 0, 0);
1888	if (!info) {
1889		/*
1890		 * oops didn't find an extent that matched the space we wanted
1891		 * to remove, look for a bitmap instead
1892		 */
1893		info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
1894					  1, 0);
1895		if (!info) {
1896			/* the tree logging code might be calling us before we
1897			 * have fully loaded the free space rbtree for this
1898			 * block group.  So it is possible the entry won't
1899			 * be in the rbtree yet at all.  The caching code
1900			 * will make sure not to put it in the rbtree if
1901			 * the logging code has pinned it.
1902			 */
 
1903			goto out_lock;
1904		}
1905	}
1906
 
1907	if (!info->bitmap) {
1908		unlink_free_space(ctl, info);
1909		if (offset == info->offset) {
1910			u64 to_free = min(bytes, info->bytes);
1911
1912			info->bytes -= to_free;
1913			info->offset += to_free;
1914			if (info->bytes) {
1915				ret = link_free_space(ctl, info);
1916				WARN_ON(ret);
1917			} else {
1918				kmem_cache_free(btrfs_free_space_cachep, info);
1919			}
1920
1921			offset += to_free;
1922			bytes -= to_free;
1923			goto again;
1924		} else {
1925			u64 old_end = info->bytes + info->offset;
1926
1927			info->bytes = offset - info->offset;
1928			ret = link_free_space(ctl, info);
1929			WARN_ON(ret);
1930			if (ret)
1931				goto out_lock;
1932
1933			/* Not enough bytes in this entry to satisfy us */
1934			if (old_end < offset + bytes) {
1935				bytes -= old_end - offset;
1936				offset = old_end;
1937				goto again;
1938			} else if (old_end == offset + bytes) {
1939				/* all done */
1940				goto out_lock;
1941			}
1942			spin_unlock(&ctl->tree_lock);
1943
1944			ret = btrfs_add_free_space(block_group, offset + bytes,
1945						   old_end - (offset + bytes));
 
 
1946			WARN_ON(ret);
1947			goto out;
1948		}
1949	}
1950
1951	ret = remove_from_bitmap(ctl, info, &offset, &bytes);
1952	if (ret == -EAGAIN)
 
1953		goto again;
1954	BUG_ON(ret); /* logic error */
1955out_lock:
 
1956	spin_unlock(&ctl->tree_lock);
1957out:
1958	return ret;
1959}
1960
1961void btrfs_dump_free_space(struct btrfs_block_group_cache *block_group,
1962			   u64 bytes)
1963{
 
1964	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
1965	struct btrfs_free_space *info;
1966	struct rb_node *n;
1967	int count = 0;
1968
 
 
 
 
 
 
 
 
 
 
 
 
 
1969	for (n = rb_first(&ctl->free_space_offset); n; n = rb_next(n)) {
1970		info = rb_entry(n, struct btrfs_free_space, offset_index);
1971		if (info->bytes >= bytes)
1972			count++;
1973		printk(KERN_CRIT "entry offset %llu, bytes %llu, bitmap %s\n",
1974		       (unsigned long long)info->offset,
1975		       (unsigned long long)info->bytes,
1976		       (info->bitmap) ? "yes" : "no");
1977	}
1978	printk(KERN_INFO "block group has cluster?: %s\n",
 
1979	       list_empty(&block_group->cluster_list) ? "no" : "yes");
1980	printk(KERN_INFO "%d blocks of free space at or bigger than bytes is"
1981	       "\n", count);
 
1982}
1983
1984void btrfs_init_free_space_ctl(struct btrfs_block_group_cache *block_group)
 
1985{
1986	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
1987
1988	spin_lock_init(&ctl->tree_lock);
1989	ctl->unit = block_group->sectorsize;
1990	ctl->start = block_group->key.objectid;
1991	ctl->private = block_group;
1992	ctl->op = &free_space_op;
 
 
 
1993
1994	/*
1995	 * we only want to have 32k of ram per block group for keeping
1996	 * track of free space, and if we pass 1/2 of that we want to
1997	 * start converting things over to using bitmaps
1998	 */
1999	ctl->extents_thresh = ((1024 * 32) / 2) /
2000				sizeof(struct btrfs_free_space);
2001}
2002
2003/*
2004 * for a given cluster, put all of its extents back into the free
2005 * space cache.  If the block group passed doesn't match the block group
2006 * pointed to by the cluster, someone else raced in and freed the
2007 * cluster already.  In that case, we just return without changing anything
2008 */
2009static int
2010__btrfs_return_cluster_to_free_space(
2011			     struct btrfs_block_group_cache *block_group,
2012			     struct btrfs_free_cluster *cluster)
2013{
2014	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2015	struct btrfs_free_space *entry;
2016	struct rb_node *node;
2017
 
 
2018	spin_lock(&cluster->lock);
2019	if (cluster->block_group != block_group)
2020		goto out;
 
 
2021
2022	cluster->block_group = NULL;
2023	cluster->window_start = 0;
2024	list_del_init(&cluster->block_group_list);
2025
2026	node = rb_first(&cluster->root);
2027	while (node) {
2028		bool bitmap;
2029
2030		entry = rb_entry(node, struct btrfs_free_space, offset_index);
2031		node = rb_next(&entry->offset_index);
2032		rb_erase(&entry->offset_index, &cluster->root);
 
 
 
 
 
 
 
 
 
2033
2034		bitmap = (entry->bitmap != NULL);
2035		if (!bitmap)
2036			try_merge_free_space(ctl, entry, false);
2037		tree_insert_offset(&ctl->free_space_offset,
2038				   entry->offset, &entry->offset_index, bitmap);
 
 
 
 
 
 
 
 
 
 
2039	}
2040	cluster->root = RB_ROOT;
2041
2042out:
2043	spin_unlock(&cluster->lock);
2044	btrfs_put_block_group(block_group);
2045	return 0;
2046}
2047
2048void __btrfs_remove_free_space_cache_locked(struct btrfs_free_space_ctl *ctl)
2049{
2050	struct btrfs_free_space *info;
2051	struct rb_node *node;
2052
2053	while ((node = rb_last(&ctl->free_space_offset)) != NULL) {
2054		info = rb_entry(node, struct btrfs_free_space, offset_index);
2055		if (!info->bitmap) {
2056			unlink_free_space(ctl, info);
2057			kmem_cache_free(btrfs_free_space_cachep, info);
2058		} else {
2059			free_bitmap(ctl, info);
2060		}
2061		if (need_resched()) {
2062			spin_unlock(&ctl->tree_lock);
2063			cond_resched();
2064			spin_lock(&ctl->tree_lock);
2065		}
2066	}
2067}
2068
2069void __btrfs_remove_free_space_cache(struct btrfs_free_space_ctl *ctl)
2070{
2071	spin_lock(&ctl->tree_lock);
2072	__btrfs_remove_free_space_cache_locked(ctl);
2073	spin_unlock(&ctl->tree_lock);
2074}
2075
2076void btrfs_remove_free_space_cache(struct btrfs_block_group_cache *block_group)
2077{
2078	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2079	struct btrfs_free_cluster *cluster;
2080	struct list_head *head;
2081
2082	spin_lock(&ctl->tree_lock);
2083	while ((head = block_group->cluster_list.next) !=
2084	       &block_group->cluster_list) {
2085		cluster = list_entry(head, struct btrfs_free_cluster,
2086				     block_group_list);
2087
2088		WARN_ON(cluster->block_group != block_group);
2089		__btrfs_return_cluster_to_free_space(block_group, cluster);
2090		if (need_resched()) {
2091			spin_unlock(&ctl->tree_lock);
2092			cond_resched();
2093			spin_lock(&ctl->tree_lock);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2094		}
 
 
2095	}
2096	__btrfs_remove_free_space_cache_locked(ctl);
2097	spin_unlock(&ctl->tree_lock);
2098
2099}
2100
2101u64 btrfs_find_space_for_alloc(struct btrfs_block_group_cache *block_group,
2102			       u64 offset, u64 bytes, u64 empty_size)
 
2103{
2104	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
 
 
2105	struct btrfs_free_space *entry = NULL;
2106	u64 bytes_search = bytes + empty_size;
2107	u64 ret = 0;
 
 
 
 
 
 
2108
2109	spin_lock(&ctl->tree_lock);
2110	entry = find_free_space(ctl, &offset, &bytes_search);
 
 
2111	if (!entry)
2112		goto out;
2113
2114	ret = offset;
2115	if (entry->bitmap) {
2116		bitmap_clear_bits(ctl, entry, offset, bytes);
 
 
 
 
2117		if (!entry->bytes)
2118			free_bitmap(ctl, entry);
2119	} else {
2120		unlink_free_space(ctl, entry);
2121		entry->offset += bytes;
2122		entry->bytes -= bytes;
 
 
 
 
 
 
 
 
 
2123		if (!entry->bytes)
2124			kmem_cache_free(btrfs_free_space_cachep, entry);
2125		else
2126			link_free_space(ctl, entry);
2127	}
2128
2129out:
 
2130	spin_unlock(&ctl->tree_lock);
2131
 
 
 
2132	return ret;
2133}
2134
2135/*
2136 * given a cluster, put all of its extents back into the free space
2137 * cache.  If a block group is passed, this function will only free
2138 * a cluster that belongs to the passed block group.
2139 *
2140 * Otherwise, it'll get a reference on the block group pointed to by the
2141 * cluster and remove the cluster from it.
2142 */
2143int btrfs_return_cluster_to_free_space(
2144			       struct btrfs_block_group_cache *block_group,
2145			       struct btrfs_free_cluster *cluster)
2146{
2147	struct btrfs_free_space_ctl *ctl;
2148	int ret;
2149
2150	/* first, get a safe pointer to the block group */
2151	spin_lock(&cluster->lock);
2152	if (!block_group) {
2153		block_group = cluster->block_group;
2154		if (!block_group) {
2155			spin_unlock(&cluster->lock);
2156			return 0;
2157		}
2158	} else if (cluster->block_group != block_group) {
2159		/* someone else has already freed it don't redo their work */
2160		spin_unlock(&cluster->lock);
2161		return 0;
2162	}
2163	atomic_inc(&block_group->count);
2164	spin_unlock(&cluster->lock);
2165
2166	ctl = block_group->free_space_ctl;
2167
2168	/* now return any extents the cluster had on it */
2169	spin_lock(&ctl->tree_lock);
2170	ret = __btrfs_return_cluster_to_free_space(block_group, cluster);
2171	spin_unlock(&ctl->tree_lock);
2172
 
 
2173	/* finally drop our ref */
2174	btrfs_put_block_group(block_group);
2175	return ret;
2176}
2177
2178static u64 btrfs_alloc_from_bitmap(struct btrfs_block_group_cache *block_group,
2179				   struct btrfs_free_cluster *cluster,
2180				   struct btrfs_free_space *entry,
2181				   u64 bytes, u64 min_start)
 
2182{
2183	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2184	int err;
2185	u64 search_start = cluster->window_start;
2186	u64 search_bytes = bytes;
2187	u64 ret = 0;
2188
2189	search_start = min_start;
2190	search_bytes = bytes;
2191
2192	err = search_bitmap(ctl, entry, &search_start, &search_bytes);
2193	if (err)
 
 
2194		return 0;
 
2195
2196	ret = search_start;
2197	__bitmap_clear_bits(ctl, entry, ret, bytes);
2198
2199	return ret;
2200}
2201
2202/*
2203 * given a cluster, try to allocate 'bytes' from it, returns 0
2204 * if it couldn't find anything suitably large, or a logical disk offset
2205 * if things worked out
2206 */
2207u64 btrfs_alloc_from_cluster(struct btrfs_block_group_cache *block_group,
2208			     struct btrfs_free_cluster *cluster, u64 bytes,
2209			     u64 min_start)
2210{
2211	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
 
 
2212	struct btrfs_free_space *entry = NULL;
2213	struct rb_node *node;
2214	u64 ret = 0;
2215
 
 
2216	spin_lock(&cluster->lock);
2217	if (bytes > cluster->max_size)
2218		goto out;
2219
2220	if (cluster->block_group != block_group)
2221		goto out;
2222
2223	node = rb_first(&cluster->root);
2224	if (!node)
2225		goto out;
2226
2227	entry = rb_entry(node, struct btrfs_free_space, offset_index);
2228	while(1) {
 
 
 
 
2229		if (entry->bytes < bytes ||
2230		    (!entry->bitmap && entry->offset < min_start)) {
2231			node = rb_next(&entry->offset_index);
2232			if (!node)
2233				break;
2234			entry = rb_entry(node, struct btrfs_free_space,
2235					 offset_index);
2236			continue;
2237		}
2238
2239		if (entry->bitmap) {
2240			ret = btrfs_alloc_from_bitmap(block_group,
2241						      cluster, entry, bytes,
2242						      cluster->window_start);
 
2243			if (ret == 0) {
2244				node = rb_next(&entry->offset_index);
2245				if (!node)
2246					break;
2247				entry = rb_entry(node, struct btrfs_free_space,
2248						 offset_index);
2249				continue;
2250			}
2251			cluster->window_start += bytes;
2252		} else {
2253			ret = entry->offset;
2254
2255			entry->offset += bytes;
2256			entry->bytes -= bytes;
2257		}
2258
2259		if (entry->bytes == 0)
2260			rb_erase(&entry->offset_index, &cluster->root);
2261		break;
2262	}
2263out:
2264	spin_unlock(&cluster->lock);
2265
2266	if (!ret)
2267		return 0;
2268
2269	spin_lock(&ctl->tree_lock);
2270
 
 
 
2271	ctl->free_space -= bytes;
 
 
 
 
2272	if (entry->bytes == 0) {
 
2273		ctl->free_extents--;
2274		if (entry->bitmap) {
2275			kfree(entry->bitmap);
 
2276			ctl->total_bitmaps--;
2277			ctl->op->recalc_thresholds(ctl);
 
 
2278		}
2279		kmem_cache_free(btrfs_free_space_cachep, entry);
2280	}
2281
 
2282	spin_unlock(&ctl->tree_lock);
2283
2284	return ret;
2285}
2286
2287static int btrfs_bitmap_cluster(struct btrfs_block_group_cache *block_group,
2288				struct btrfs_free_space *entry,
2289				struct btrfs_free_cluster *cluster,
2290				u64 offset, u64 bytes,
2291				u64 cont1_bytes, u64 min_bytes)
2292{
2293	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2294	unsigned long next_zero;
2295	unsigned long i;
2296	unsigned long want_bits;
2297	unsigned long min_bits;
2298	unsigned long found_bits;
 
2299	unsigned long start = 0;
2300	unsigned long total_found = 0;
2301	int ret;
2302
2303	i = offset_to_bit(entry->offset, block_group->sectorsize,
 
 
2304			  max_t(u64, offset, entry->offset));
2305	want_bits = bytes_to_bits(bytes, block_group->sectorsize);
2306	min_bits = bytes_to_bits(min_bytes, block_group->sectorsize);
2307
 
 
 
 
 
 
 
2308again:
2309	found_bits = 0;
2310	for (i = find_next_bit(entry->bitmap, BITS_PER_BITMAP, i);
2311	     i < BITS_PER_BITMAP;
2312	     i = find_next_bit(entry->bitmap, BITS_PER_BITMAP, i + 1)) {
2313		next_zero = find_next_zero_bit(entry->bitmap,
2314					       BITS_PER_BITMAP, i);
2315		if (next_zero - i >= min_bits) {
2316			found_bits = next_zero - i;
 
 
2317			break;
2318		}
 
 
2319		i = next_zero;
2320	}
2321
2322	if (!found_bits)
 
2323		return -ENOSPC;
 
2324
2325	if (!total_found) {
2326		start = i;
2327		cluster->max_size = 0;
2328	}
2329
2330	total_found += found_bits;
2331
2332	if (cluster->max_size < found_bits * block_group->sectorsize)
2333		cluster->max_size = found_bits * block_group->sectorsize;
2334
2335	if (total_found < want_bits || cluster->max_size < cont1_bytes) {
2336		i = next_zero + 1;
2337		goto again;
2338	}
2339
2340	cluster->window_start = start * block_group->sectorsize +
2341		entry->offset;
2342	rb_erase(&entry->offset_index, &ctl->free_space_offset);
2343	ret = tree_insert_offset(&cluster->root, entry->offset,
2344				 &entry->offset_index, 1);
2345	BUG_ON(ret); /* -EEXIST; Logic error */
 
 
 
 
 
 
 
 
 
 
2346
2347	trace_btrfs_setup_cluster(block_group, cluster,
2348				  total_found * block_group->sectorsize, 1);
2349	return 0;
2350}
2351
2352/*
2353 * This searches the block group for just extents to fill the cluster with.
2354 * Try to find a cluster with at least bytes total bytes, at least one
2355 * extent of cont1_bytes, and other clusters of at least min_bytes.
2356 */
2357static noinline int
2358setup_cluster_no_bitmap(struct btrfs_block_group_cache *block_group,
2359			struct btrfs_free_cluster *cluster,
2360			struct list_head *bitmaps, u64 offset, u64 bytes,
2361			u64 cont1_bytes, u64 min_bytes)
2362{
2363	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2364	struct btrfs_free_space *first = NULL;
2365	struct btrfs_free_space *entry = NULL;
2366	struct btrfs_free_space *last;
2367	struct rb_node *node;
2368	u64 window_start;
2369	u64 window_free;
2370	u64 max_extent;
2371	u64 total_size = 0;
2372
 
 
2373	entry = tree_search_offset(ctl, offset, 0, 1);
2374	if (!entry)
2375		return -ENOSPC;
2376
2377	/*
2378	 * We don't want bitmaps, so just move along until we find a normal
2379	 * extent entry.
2380	 */
2381	while (entry->bitmap || entry->bytes < min_bytes) {
2382		if (entry->bitmap && list_empty(&entry->list))
2383			list_add_tail(&entry->list, bitmaps);
2384		node = rb_next(&entry->offset_index);
2385		if (!node)
2386			return -ENOSPC;
2387		entry = rb_entry(node, struct btrfs_free_space, offset_index);
2388	}
2389
2390	window_start = entry->offset;
2391	window_free = entry->bytes;
2392	max_extent = entry->bytes;
2393	first = entry;
2394	last = entry;
2395
2396	for (node = rb_next(&entry->offset_index); node;
2397	     node = rb_next(&entry->offset_index)) {
2398		entry = rb_entry(node, struct btrfs_free_space, offset_index);
2399
2400		if (entry->bitmap) {
2401			if (list_empty(&entry->list))
2402				list_add_tail(&entry->list, bitmaps);
2403			continue;
2404		}
2405
2406		if (entry->bytes < min_bytes)
2407			continue;
2408
2409		last = entry;
2410		window_free += entry->bytes;
2411		if (entry->bytes > max_extent)
2412			max_extent = entry->bytes;
2413	}
2414
2415	if (window_free < bytes || max_extent < cont1_bytes)
2416		return -ENOSPC;
2417
2418	cluster->window_start = first->offset;
2419
2420	node = &first->offset_index;
2421
2422	/*
2423	 * now we've found our entries, pull them out of the free space
2424	 * cache and put them into the cluster rbtree
2425	 */
2426	do {
2427		int ret;
2428
2429		entry = rb_entry(node, struct btrfs_free_space, offset_index);
2430		node = rb_next(&entry->offset_index);
2431		if (entry->bitmap || entry->bytes < min_bytes)
2432			continue;
2433
2434		rb_erase(&entry->offset_index, &ctl->free_space_offset);
2435		ret = tree_insert_offset(&cluster->root, entry->offset,
2436					 &entry->offset_index, 0);
2437		total_size += entry->bytes;
2438		BUG_ON(ret); /* -EEXIST; Logic error */
2439	} while (node && entry != last);
2440
2441	cluster->max_size = max_extent;
2442	trace_btrfs_setup_cluster(block_group, cluster, total_size, 0);
2443	return 0;
2444}
2445
2446/*
2447 * This specifically looks for bitmaps that may work in the cluster, we assume
2448 * that we have already failed to find extents that will work.
2449 */
2450static noinline int
2451setup_cluster_bitmap(struct btrfs_block_group_cache *block_group,
2452		     struct btrfs_free_cluster *cluster,
2453		     struct list_head *bitmaps, u64 offset, u64 bytes,
2454		     u64 cont1_bytes, u64 min_bytes)
2455{
2456	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2457	struct btrfs_free_space *entry;
2458	int ret = -ENOSPC;
2459	u64 bitmap_offset = offset_to_bitmap(ctl, offset);
2460
2461	if (ctl->total_bitmaps == 0)
2462		return -ENOSPC;
2463
2464	/*
2465	 * The bitmap that covers offset won't be in the list unless offset
2466	 * is just its start offset.
2467	 */
2468	entry = list_first_entry(bitmaps, struct btrfs_free_space, list);
2469	if (entry->offset != bitmap_offset) {
 
 
2470		entry = tree_search_offset(ctl, bitmap_offset, 1, 0);
2471		if (entry && list_empty(&entry->list))
2472			list_add(&entry->list, bitmaps);
2473	}
2474
2475	list_for_each_entry(entry, bitmaps, list) {
2476		if (entry->bytes < bytes)
2477			continue;
2478		ret = btrfs_bitmap_cluster(block_group, entry, cluster, offset,
2479					   bytes, cont1_bytes, min_bytes);
2480		if (!ret)
2481			return 0;
2482	}
2483
2484	/*
2485	 * The bitmaps list has all the bitmaps that record free space
2486	 * starting after offset, so no more search is required.
2487	 */
2488	return -ENOSPC;
2489}
2490
2491/*
2492 * here we try to find a cluster of blocks in a block group.  The goal
2493 * is to find at least bytes+empty_size.
2494 * We might not find them all in one contiguous area.
2495 *
2496 * returns zero and sets up cluster if things worked out, otherwise
2497 * it returns -enospc
2498 */
2499int btrfs_find_space_cluster(struct btrfs_trans_handle *trans,
2500			     struct btrfs_root *root,
2501			     struct btrfs_block_group_cache *block_group,
2502			     struct btrfs_free_cluster *cluster,
2503			     u64 offset, u64 bytes, u64 empty_size)
2504{
 
2505	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2506	struct btrfs_free_space *entry, *tmp;
2507	LIST_HEAD(bitmaps);
2508	u64 min_bytes;
2509	u64 cont1_bytes;
2510	int ret;
2511
2512	/*
2513	 * Choose the minimum extent size we'll require for this
2514	 * cluster.  For SSD_SPREAD, don't allow any fragmentation.
2515	 * For metadata, allow allocates with smaller extents.  For
2516	 * data, keep it dense.
2517	 */
2518	if (btrfs_test_opt(root, SSD_SPREAD)) {
2519		cont1_bytes = min_bytes = bytes + empty_size;
 
2520	} else if (block_group->flags & BTRFS_BLOCK_GROUP_METADATA) {
2521		cont1_bytes = bytes;
2522		min_bytes = block_group->sectorsize;
2523	} else {
2524		cont1_bytes = max(bytes, (bytes + empty_size) >> 2);
2525		min_bytes = block_group->sectorsize;
2526	}
2527
2528	spin_lock(&ctl->tree_lock);
2529
2530	/*
2531	 * If we know we don't have enough space to make a cluster don't even
2532	 * bother doing all the work to try and find one.
2533	 */
2534	if (ctl->free_space < bytes) {
2535		spin_unlock(&ctl->tree_lock);
2536		return -ENOSPC;
2537	}
2538
2539	spin_lock(&cluster->lock);
2540
2541	/* someone already found a cluster, hooray */
2542	if (cluster->block_group) {
2543		ret = 0;
2544		goto out;
2545	}
2546
2547	trace_btrfs_find_cluster(block_group, offset, bytes, empty_size,
2548				 min_bytes);
2549
2550	INIT_LIST_HEAD(&bitmaps);
2551	ret = setup_cluster_no_bitmap(block_group, cluster, &bitmaps, offset,
2552				      bytes + empty_size,
2553				      cont1_bytes, min_bytes);
2554	if (ret)
2555		ret = setup_cluster_bitmap(block_group, cluster, &bitmaps,
2556					   offset, bytes + empty_size,
2557					   cont1_bytes, min_bytes);
2558
2559	/* Clear our temporary list */
2560	list_for_each_entry_safe(entry, tmp, &bitmaps, list)
2561		list_del_init(&entry->list);
2562
2563	if (!ret) {
2564		atomic_inc(&block_group->count);
2565		list_add_tail(&cluster->block_group_list,
2566			      &block_group->cluster_list);
2567		cluster->block_group = block_group;
2568	} else {
2569		trace_btrfs_failed_cluster_setup(block_group);
2570	}
2571out:
2572	spin_unlock(&cluster->lock);
2573	spin_unlock(&ctl->tree_lock);
2574
2575	return ret;
2576}
2577
2578/*
2579 * simple code to zero out a cluster
2580 */
2581void btrfs_init_free_cluster(struct btrfs_free_cluster *cluster)
2582{
2583	spin_lock_init(&cluster->lock);
2584	spin_lock_init(&cluster->refill_lock);
2585	cluster->root = RB_ROOT;
2586	cluster->max_size = 0;
 
2587	INIT_LIST_HEAD(&cluster->block_group_list);
2588	cluster->block_group = NULL;
2589}
2590
2591static int do_trimming(struct btrfs_block_group_cache *block_group,
2592		       u64 *total_trimmed, u64 start, u64 bytes,
2593		       u64 reserved_start, u64 reserved_bytes)
 
 
2594{
2595	struct btrfs_space_info *space_info = block_group->space_info;
2596	struct btrfs_fs_info *fs_info = block_group->fs_info;
 
2597	int ret;
2598	int update = 0;
 
 
 
2599	u64 trimmed = 0;
2600
2601	spin_lock(&space_info->lock);
2602	spin_lock(&block_group->lock);
2603	if (!block_group->ro) {
2604		block_group->reserved += reserved_bytes;
2605		space_info->bytes_reserved += reserved_bytes;
2606		update = 1;
2607	}
2608	spin_unlock(&block_group->lock);
2609	spin_unlock(&space_info->lock);
2610
2611	ret = btrfs_error_discard_extent(fs_info->extent_root,
2612					 start, bytes, &trimmed);
2613	if (!ret)
2614		*total_trimmed += trimmed;
 
 
2615
2616	btrfs_add_free_space(block_group, reserved_start, reserved_bytes);
 
 
 
 
 
 
 
 
 
 
2617
2618	if (update) {
2619		spin_lock(&space_info->lock);
2620		spin_lock(&block_group->lock);
2621		if (block_group->ro)
2622			space_info->bytes_readonly += reserved_bytes;
2623		block_group->reserved -= reserved_bytes;
2624		space_info->bytes_reserved -= reserved_bytes;
 
2625		spin_unlock(&space_info->lock);
2626		spin_unlock(&block_group->lock);
2627	}
2628
2629	return ret;
2630}
2631
2632static int trim_no_bitmap(struct btrfs_block_group_cache *block_group,
2633			  u64 *total_trimmed, u64 start, u64 end, u64 minlen)
 
 
 
 
2634{
 
 
2635	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2636	struct btrfs_free_space *entry;
2637	struct rb_node *node;
2638	int ret = 0;
2639	u64 extent_start;
2640	u64 extent_bytes;
 
2641	u64 bytes;
 
2642
2643	while (start < end) {
 
 
 
2644		spin_lock(&ctl->tree_lock);
2645
2646		if (ctl->free_space < minlen) {
2647			spin_unlock(&ctl->tree_lock);
2648			break;
2649		}
2650
2651		entry = tree_search_offset(ctl, start, 0, 1);
2652		if (!entry) {
2653			spin_unlock(&ctl->tree_lock);
2654			break;
2655		}
2656
2657		/* skip bitmaps */
2658		while (entry->bitmap) {
 
2659			node = rb_next(&entry->offset_index);
2660			if (!node) {
2661				spin_unlock(&ctl->tree_lock);
2662				goto out;
2663			}
2664			entry = rb_entry(node, struct btrfs_free_space,
2665					 offset_index);
2666		}
2667
2668		if (entry->offset >= end) {
2669			spin_unlock(&ctl->tree_lock);
2670			break;
2671		}
2672
2673		extent_start = entry->offset;
2674		extent_bytes = entry->bytes;
2675		start = max(start, extent_start);
2676		bytes = min(extent_start + extent_bytes, end) - start;
2677		if (bytes < minlen) {
2678			spin_unlock(&ctl->tree_lock);
2679			goto next;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2680		}
2681
2682		unlink_free_space(ctl, entry);
2683		kmem_cache_free(btrfs_free_space_cachep, entry);
2684
2685		spin_unlock(&ctl->tree_lock);
 
 
 
 
2686
2687		ret = do_trimming(block_group, total_trimmed, start, bytes,
2688				  extent_start, extent_bytes);
2689		if (ret)
 
 
2690			break;
 
2691next:
2692		start += bytes;
 
 
 
2693
2694		if (fatal_signal_pending(current)) {
2695			ret = -ERESTARTSYS;
2696			break;
2697		}
2698
2699		cond_resched();
2700	}
2701out:
 
 
 
 
 
 
 
2702	return ret;
2703}
2704
2705static int trim_bitmaps(struct btrfs_block_group_cache *block_group,
2706			u64 *total_trimmed, u64 start, u64 end, u64 minlen)
 
 
 
 
 
 
 
 
 
 
 
 
 
2707{
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2708	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2709	struct btrfs_free_space *entry;
2710	int ret = 0;
2711	int ret2;
2712	u64 bytes;
2713	u64 offset = offset_to_bitmap(ctl, start);
 
2714
2715	while (offset < end) {
2716		bool next_bitmap = false;
 
2717
 
2718		spin_lock(&ctl->tree_lock);
2719
2720		if (ctl->free_space < minlen) {
 
 
2721			spin_unlock(&ctl->tree_lock);
 
2722			break;
2723		}
2724
2725		entry = tree_search_offset(ctl, offset, 1, 0);
2726		if (!entry) {
 
 
 
 
 
 
 
 
 
2727			spin_unlock(&ctl->tree_lock);
 
2728			next_bitmap = true;
2729			goto next;
2730		}
2731
 
 
 
 
 
 
 
 
 
2732		bytes = minlen;
2733		ret2 = search_bitmap(ctl, entry, &start, &bytes);
2734		if (ret2 || start >= end) {
 
 
 
 
 
 
 
 
2735			spin_unlock(&ctl->tree_lock);
 
2736			next_bitmap = true;
2737			goto next;
2738		}
2739
 
 
 
 
 
 
 
 
 
 
2740		bytes = min(bytes, end - start);
2741		if (bytes < minlen) {
2742			spin_unlock(&ctl->tree_lock);
 
2743			goto next;
2744		}
2745
2746		bitmap_clear_bits(ctl, entry, start, bytes);
 
 
 
 
 
 
 
 
 
 
 
2747		if (entry->bytes == 0)
2748			free_bitmap(ctl, entry);
2749
2750		spin_unlock(&ctl->tree_lock);
 
 
 
 
2751
2752		ret = do_trimming(block_group, total_trimmed, start, bytes,
2753				  start, bytes);
2754		if (ret)
 
 
 
2755			break;
 
2756next:
2757		if (next_bitmap) {
2758			offset += BITS_PER_BITMAP * ctl->unit;
 
2759		} else {
2760			start += bytes;
2761			if (start >= offset + BITS_PER_BITMAP * ctl->unit)
2762				offset += BITS_PER_BITMAP * ctl->unit;
2763		}
 
2764
2765		if (fatal_signal_pending(current)) {
 
 
2766			ret = -ERESTARTSYS;
2767			break;
2768		}
2769
2770		cond_resched();
2771	}
2772
 
 
 
 
2773	return ret;
2774}
2775
2776int btrfs_trim_block_group(struct btrfs_block_group_cache *block_group,
2777			   u64 *trimmed, u64 start, u64 end, u64 minlen)
2778{
 
2779	int ret;
 
 
 
2780
2781	*trimmed = 0;
2782
2783	ret = trim_no_bitmap(block_group, trimmed, start, end, minlen);
 
 
 
 
 
 
 
 
2784	if (ret)
2785		return ret;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2786
2787	ret = trim_bitmaps(block_group, trimmed, start, end, minlen);
 
2788
2789	return ret;
2790}
2791
2792/*
2793 * Find the left-most item in the cache tree, and then return the
2794 * smallest inode number in the item.
2795 *
2796 * Note: the returned inode number may not be the smallest one in
2797 * the tree, if the left-most item is a bitmap.
2798 */
2799u64 btrfs_find_ino_for_alloc(struct btrfs_root *fs_root)
2800{
2801	struct btrfs_free_space_ctl *ctl = fs_root->free_ino_ctl;
2802	struct btrfs_free_space *entry = NULL;
2803	u64 ino = 0;
 
 
 
 
 
 
 
 
2804
2805	spin_lock(&ctl->tree_lock);
 
2806
2807	if (RB_EMPTY_ROOT(&ctl->free_space_offset))
2808		goto out;
2809
2810	entry = rb_entry(rb_first(&ctl->free_space_offset),
2811			 struct btrfs_free_space, offset_index);
2812
2813	if (!entry->bitmap) {
2814		ino = entry->offset;
 
 
2815
2816		unlink_free_space(ctl, entry);
2817		entry->offset++;
2818		entry->bytes--;
2819		if (!entry->bytes)
2820			kmem_cache_free(btrfs_free_space_cachep, entry);
2821		else
2822			link_free_space(ctl, entry);
2823	} else {
2824		u64 offset = 0;
2825		u64 count = 1;
2826		int ret;
2827
2828		ret = search_bitmap(ctl, entry, &offset, &count);
2829		/* Logic error; Should be empty if it can't find anything */
2830		BUG_ON(ret);
2831
2832		ino = offset;
2833		bitmap_clear_bits(ctl, entry, offset, 1);
2834		if (entry->bytes == 0)
2835			free_bitmap(ctl, entry);
 
 
 
2836	}
2837out:
2838	spin_unlock(&ctl->tree_lock);
2839
2840	return ino;
2841}
2842
2843struct inode *lookup_free_ino_inode(struct btrfs_root *root,
2844				    struct btrfs_path *path)
2845{
2846	struct inode *inode = NULL;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2847
2848	spin_lock(&root->cache_lock);
2849	if (root->cache_inode)
2850		inode = igrab(root->cache_inode);
2851	spin_unlock(&root->cache_lock);
2852	if (inode)
2853		return inode;
2854
2855	inode = __lookup_free_space_inode(root, path, 0);
2856	if (IS_ERR(inode))
2857		return inode;
 
 
 
 
2858
2859	spin_lock(&root->cache_lock);
2860	if (!btrfs_fs_closing(root->fs_info))
2861		root->cache_inode = igrab(inode);
2862	spin_unlock(&root->cache_lock);
 
 
 
2863
2864	return inode;
2865}
2866
2867int create_free_ino_inode(struct btrfs_root *root,
2868			  struct btrfs_trans_handle *trans,
2869			  struct btrfs_path *path)
2870{
2871	return __create_free_space_inode(root, trans, path,
2872					 BTRFS_FREE_INO_OBJECTID, 0);
2873}
2874
2875int load_free_ino_cache(struct btrfs_fs_info *fs_info, struct btrfs_root *root)
 
 
 
 
 
 
 
 
2876{
2877	struct btrfs_free_space_ctl *ctl = root->free_ino_ctl;
2878	struct btrfs_path *path;
2879	struct inode *inode;
2880	int ret = 0;
2881	u64 root_gen = btrfs_root_generation(&root->root_item);
 
 
 
 
 
 
 
 
2882
2883	if (!btrfs_test_opt(root, INODE_MAP_CACHE))
2884		return 0;
 
 
 
 
 
 
 
 
 
2885
2886	/*
2887	 * If we're unmounting then just return, since this does a search on the
2888	 * normal root and not the commit root and we could deadlock.
2889	 */
2890	if (btrfs_fs_closing(fs_info))
2891		return 0;
 
2892
2893	path = btrfs_alloc_path();
2894	if (!path)
2895		return 0;
 
 
 
 
 
 
 
2896
2897	inode = lookup_free_ino_inode(root, path);
2898	if (IS_ERR(inode))
2899		goto out;
2900
2901	if (root_gen != BTRFS_I(inode)->generation)
2902		goto out_put;
 
2903
2904	ret = __load_free_space_cache(root, inode, ctl, path, 0);
 
2905
2906	if (ret < 0)
2907		printk(KERN_ERR "btrfs: failed to load free ino cache for "
2908		       "root %llu\n", root->root_key.objectid);
2909out_put:
2910	iput(inode);
2911out:
2912	btrfs_free_path(path);
2913	return ret;
2914}
2915
2916int btrfs_write_out_ino_cache(struct btrfs_root *root,
2917			      struct btrfs_trans_handle *trans,
2918			      struct btrfs_path *path)
 
 
 
 
2919{
2920	struct btrfs_free_space_ctl *ctl = root->free_ino_ctl;
2921	struct inode *inode;
2922	int ret;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2923
2924	if (!btrfs_test_opt(root, INODE_MAP_CACHE))
2925		return 0;
 
 
 
 
 
 
 
 
 
 
 
2926
2927	inode = lookup_free_ino_inode(root, path);
2928	if (IS_ERR(inode))
2929		return 0;
2930
2931	ret = __btrfs_write_out_cache(root, inode, ctl, NULL, trans, path, 0);
2932	if (ret) {
2933		btrfs_delalloc_release_metadata(inode, inode->i_size);
2934#ifdef DEBUG
2935		printk(KERN_ERR "btrfs: failed to write free ino cache "
2936		       "for root %llu\n", root->root_key.objectid);
2937#endif
2938	}
2939
2940	iput(inode);
 
 
 
2941	return ret;
2942}