free-space-cache.c 79.9 KB
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/*
 * Copyright (C) 2008 Red Hat.  All rights reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public
 * License v2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public
 * License along with this program; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 021110-1307, USA.
 */

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#include <linux/pagemap.h>
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#include <linux/sched.h>
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#include <linux/slab.h>
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#include <linux/math64.h>
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#include <linux/ratelimit.h>
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#include "ctree.h"
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#include "free-space-cache.h"
#include "transaction.h"
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#include "disk-io.h"
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#include "extent_io.h"
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#include "inode-map.h"
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#define BITS_PER_BITMAP		(PAGE_CACHE_SIZE * 8)
#define MAX_CACHE_BYTES_PER_GIG	(32 * 1024)
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static int link_free_space(struct btrfs_free_space_ctl *ctl,
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			   struct btrfs_free_space *info);
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static void unlink_free_space(struct btrfs_free_space_ctl *ctl,
			      struct btrfs_free_space *info);
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static struct inode *__lookup_free_space_inode(struct btrfs_root *root,
					       struct btrfs_path *path,
					       u64 offset)
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{
	struct btrfs_key key;
	struct btrfs_key location;
	struct btrfs_disk_key disk_key;
	struct btrfs_free_space_header *header;
	struct extent_buffer *leaf;
	struct inode *inode = NULL;
	int ret;

	key.objectid = BTRFS_FREE_SPACE_OBJECTID;
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	key.offset = offset;
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	key.type = 0;

	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
	if (ret < 0)
		return ERR_PTR(ret);
	if (ret > 0) {
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		btrfs_release_path(path);
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		return ERR_PTR(-ENOENT);
	}

	leaf = path->nodes[0];
	header = btrfs_item_ptr(leaf, path->slots[0],
				struct btrfs_free_space_header);
	btrfs_free_space_key(leaf, header, &disk_key);
	btrfs_disk_key_to_cpu(&location, &disk_key);
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	btrfs_release_path(path);
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	inode = btrfs_iget(root->fs_info->sb, &location, root, NULL);
	if (!inode)
		return ERR_PTR(-ENOENT);
	if (IS_ERR(inode))
		return inode;
	if (is_bad_inode(inode)) {
		iput(inode);
		return ERR_PTR(-ENOENT);
	}

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	mapping_set_gfp_mask(inode->i_mapping,
			mapping_gfp_mask(inode->i_mapping) & ~__GFP_FS);
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	return inode;
}

struct inode *lookup_free_space_inode(struct btrfs_root *root,
				      struct btrfs_block_group_cache
				      *block_group, struct btrfs_path *path)
{
	struct inode *inode = NULL;
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	u32 flags = BTRFS_INODE_NODATASUM | BTRFS_INODE_NODATACOW;
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	spin_lock(&block_group->lock);
	if (block_group->inode)
		inode = igrab(block_group->inode);
	spin_unlock(&block_group->lock);
	if (inode)
		return inode;

	inode = __lookup_free_space_inode(root, path,
					  block_group->key.objectid);
	if (IS_ERR(inode))
		return inode;

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	spin_lock(&block_group->lock);
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	if (!((BTRFS_I(inode)->flags & flags) == flags)) {
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		btrfs_info(root->fs_info,
			"Old style space inode found, converting.");
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		BTRFS_I(inode)->flags |= BTRFS_INODE_NODATASUM |
			BTRFS_INODE_NODATACOW;
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		block_group->disk_cache_state = BTRFS_DC_CLEAR;
	}

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	if (!block_group->iref) {
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		block_group->inode = igrab(inode);
		block_group->iref = 1;
	}
	spin_unlock(&block_group->lock);

	return inode;
}

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static int __create_free_space_inode(struct btrfs_root *root,
				     struct btrfs_trans_handle *trans,
				     struct btrfs_path *path,
				     u64 ino, u64 offset)
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{
	struct btrfs_key key;
	struct btrfs_disk_key disk_key;
	struct btrfs_free_space_header *header;
	struct btrfs_inode_item *inode_item;
	struct extent_buffer *leaf;
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	u64 flags = BTRFS_INODE_NOCOMPRESS | BTRFS_INODE_PREALLOC;
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	int ret;

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	ret = btrfs_insert_empty_inode(trans, root, path, ino);
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	if (ret)
		return ret;

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	/* We inline crc's for the free disk space cache */
	if (ino != BTRFS_FREE_INO_OBJECTID)
		flags |= BTRFS_INODE_NODATASUM | BTRFS_INODE_NODATACOW;

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	leaf = path->nodes[0];
	inode_item = btrfs_item_ptr(leaf, path->slots[0],
				    struct btrfs_inode_item);
	btrfs_item_key(leaf, &disk_key, path->slots[0]);
	memset_extent_buffer(leaf, 0, (unsigned long)inode_item,
			     sizeof(*inode_item));
	btrfs_set_inode_generation(leaf, inode_item, trans->transid);
	btrfs_set_inode_size(leaf, inode_item, 0);
	btrfs_set_inode_nbytes(leaf, inode_item, 0);
	btrfs_set_inode_uid(leaf, inode_item, 0);
	btrfs_set_inode_gid(leaf, inode_item, 0);
	btrfs_set_inode_mode(leaf, inode_item, S_IFREG | 0600);
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	btrfs_set_inode_flags(leaf, inode_item, flags);
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	btrfs_set_inode_nlink(leaf, inode_item, 1);
	btrfs_set_inode_transid(leaf, inode_item, trans->transid);
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	btrfs_set_inode_block_group(leaf, inode_item, offset);
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	btrfs_mark_buffer_dirty(leaf);
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	btrfs_release_path(path);
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	key.objectid = BTRFS_FREE_SPACE_OBJECTID;
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	key.offset = offset;
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	key.type = 0;

	ret = btrfs_insert_empty_item(trans, root, path, &key,
				      sizeof(struct btrfs_free_space_header));
	if (ret < 0) {
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		btrfs_release_path(path);
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		return ret;
	}
	leaf = path->nodes[0];
	header = btrfs_item_ptr(leaf, path->slots[0],
				struct btrfs_free_space_header);
	memset_extent_buffer(leaf, 0, (unsigned long)header, sizeof(*header));
	btrfs_set_free_space_key(leaf, header, &disk_key);
	btrfs_mark_buffer_dirty(leaf);
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	btrfs_release_path(path);
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	return 0;
}

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int create_free_space_inode(struct btrfs_root *root,
			    struct btrfs_trans_handle *trans,
			    struct btrfs_block_group_cache *block_group,
			    struct btrfs_path *path)
{
	int ret;
	u64 ino;

	ret = btrfs_find_free_objectid(root, &ino);
	if (ret < 0)
		return ret;

	return __create_free_space_inode(root, trans, path, ino,
					 block_group->key.objectid);
}

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int btrfs_check_trunc_cache_free_space(struct btrfs_root *root,
				       struct btrfs_block_rsv *rsv)
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{
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	u64 needed_bytes;
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	int ret;
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	/* 1 for slack space, 1 for updating the inode */
	needed_bytes = btrfs_calc_trunc_metadata_size(root, 1) +
		btrfs_calc_trans_metadata_size(root, 1);

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	spin_lock(&rsv->lock);
	if (rsv->reserved < needed_bytes)
		ret = -ENOSPC;
	else
		ret = 0;
	spin_unlock(&rsv->lock);
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	return ret;
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}

int btrfs_truncate_free_space_cache(struct btrfs_root *root,
				    struct btrfs_trans_handle *trans,
				    struct inode *inode)
{
	int ret = 0;
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	btrfs_i_size_write(inode, 0);
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	truncate_pagecache(inode, 0);
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	/*
	 * We don't need an orphan item because truncating the free space cache
	 * will never be split across transactions.
	 */
	ret = btrfs_truncate_inode_items(trans, root, inode,
					 0, BTRFS_EXTENT_DATA_KEY);
	if (ret) {
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		btrfs_abort_transaction(trans, root, ret);
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		return ret;
	}

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	ret = btrfs_update_inode(trans, root, inode);
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	if (ret)
		btrfs_abort_transaction(trans, root, ret);
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	return ret;
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}

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static int readahead_cache(struct inode *inode)
{
	struct file_ra_state *ra;
	unsigned long last_index;

	ra = kzalloc(sizeof(*ra), GFP_NOFS);
	if (!ra)
		return -ENOMEM;

	file_ra_state_init(ra, inode->i_mapping);
	last_index = (i_size_read(inode) - 1) >> PAGE_CACHE_SHIFT;

	page_cache_sync_readahead(inode->i_mapping, ra, NULL, 0, last_index);

	kfree(ra);

	return 0;
}

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struct io_ctl {
	void *cur, *orig;
	struct page *page;
	struct page **pages;
	struct btrfs_root *root;
	unsigned long size;
	int index;
	int num_pages;
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	unsigned check_crcs:1;
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};

static int io_ctl_init(struct io_ctl *io_ctl, struct inode *inode,
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		       struct btrfs_root *root, int write)
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{
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	int num_pages;
	int check_crcs = 0;

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	num_pages = DIV_ROUND_UP(i_size_read(inode), PAGE_CACHE_SIZE);
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	if (btrfs_ino(inode) != BTRFS_FREE_INO_OBJECTID)
		check_crcs = 1;

	/* Make sure we can fit our crcs into the first page */
	if (write && check_crcs &&
	    (num_pages * sizeof(u32)) >= PAGE_CACHE_SIZE)
		return -ENOSPC;

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	memset(io_ctl, 0, sizeof(struct io_ctl));
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	io_ctl->pages = kzalloc(sizeof(struct page *) * num_pages, GFP_NOFS);
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	if (!io_ctl->pages)
		return -ENOMEM;
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	io_ctl->num_pages = num_pages;
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	io_ctl->root = root;
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	io_ctl->check_crcs = check_crcs;

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	return 0;
}

static void io_ctl_free(struct io_ctl *io_ctl)
{
	kfree(io_ctl->pages);
}

static void io_ctl_unmap_page(struct io_ctl *io_ctl)
{
	if (io_ctl->cur) {
		kunmap(io_ctl->page);
		io_ctl->cur = NULL;
		io_ctl->orig = NULL;
	}
}

static void io_ctl_map_page(struct io_ctl *io_ctl, int clear)
{
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	ASSERT(io_ctl->index < io_ctl->num_pages);
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	io_ctl->page = io_ctl->pages[io_ctl->index++];
	io_ctl->cur = kmap(io_ctl->page);
	io_ctl->orig = io_ctl->cur;
	io_ctl->size = PAGE_CACHE_SIZE;
	if (clear)
		memset(io_ctl->cur, 0, PAGE_CACHE_SIZE);
}

static void io_ctl_drop_pages(struct io_ctl *io_ctl)
{
	int i;

	io_ctl_unmap_page(io_ctl);

	for (i = 0; i < io_ctl->num_pages; i++) {
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		if (io_ctl->pages[i]) {
			ClearPageChecked(io_ctl->pages[i]);
			unlock_page(io_ctl->pages[i]);
			page_cache_release(io_ctl->pages[i]);
		}
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	}
}

static int io_ctl_prepare_pages(struct io_ctl *io_ctl, struct inode *inode,
				int uptodate)
{
	struct page *page;
	gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
	int i;

	for (i = 0; i < io_ctl->num_pages; i++) {
		page = find_or_create_page(inode->i_mapping, i, mask);
		if (!page) {
			io_ctl_drop_pages(io_ctl);
			return -ENOMEM;
		}
		io_ctl->pages[i] = page;
		if (uptodate && !PageUptodate(page)) {
			btrfs_readpage(NULL, page);
			lock_page(page);
			if (!PageUptodate(page)) {
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				btrfs_err(BTRFS_I(inode)->root->fs_info,
					   "error reading free space cache");
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				io_ctl_drop_pages(io_ctl);
				return -EIO;
			}
		}
	}

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	for (i = 0; i < io_ctl->num_pages; i++) {
		clear_page_dirty_for_io(io_ctl->pages[i]);
		set_page_extent_mapped(io_ctl->pages[i]);
	}

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	return 0;
}

static void io_ctl_set_generation(struct io_ctl *io_ctl, u64 generation)
{
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	__le64 *val;
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	io_ctl_map_page(io_ctl, 1);

	/*
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	 * Skip the csum areas.  If we don't check crcs then we just have a
	 * 64bit chunk at the front of the first page.
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	 */
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	if (io_ctl->check_crcs) {
		io_ctl->cur += (sizeof(u32) * io_ctl->num_pages);
		io_ctl->size -= sizeof(u64) + (sizeof(u32) * io_ctl->num_pages);
	} else {
		io_ctl->cur += sizeof(u64);
		io_ctl->size -= sizeof(u64) * 2;
	}
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	val = io_ctl->cur;
	*val = cpu_to_le64(generation);
	io_ctl->cur += sizeof(u64);
}

static int io_ctl_check_generation(struct io_ctl *io_ctl, u64 generation)
{
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	__le64 *gen;
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	/*
	 * Skip the crc area.  If we don't check crcs then we just have a 64bit
	 * chunk at the front of the first page.
	 */
	if (io_ctl->check_crcs) {
		io_ctl->cur += sizeof(u32) * io_ctl->num_pages;
		io_ctl->size -= sizeof(u64) +
			(sizeof(u32) * io_ctl->num_pages);
	} else {
		io_ctl->cur += sizeof(u64);
		io_ctl->size -= sizeof(u64) * 2;
	}
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	gen = io_ctl->cur;
	if (le64_to_cpu(*gen) != generation) {
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		printk_ratelimited(KERN_ERR "BTRFS: space cache generation "
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				   "(%Lu) does not match inode (%Lu)\n", *gen,
				   generation);
		io_ctl_unmap_page(io_ctl);
		return -EIO;
	}
	io_ctl->cur += sizeof(u64);
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	return 0;
}

static void io_ctl_set_crc(struct io_ctl *io_ctl, int index)
{
	u32 *tmp;
	u32 crc = ~(u32)0;
	unsigned offset = 0;

	if (!io_ctl->check_crcs) {
		io_ctl_unmap_page(io_ctl);
		return;
	}

	if (index == 0)
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		offset = sizeof(u32) * io_ctl->num_pages;
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	crc = btrfs_csum_data(io_ctl->orig + offset, crc,
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			      PAGE_CACHE_SIZE - offset);
	btrfs_csum_final(crc, (char *)&crc);
	io_ctl_unmap_page(io_ctl);
	tmp = kmap(io_ctl->pages[0]);
	tmp += index;
	*tmp = crc;
	kunmap(io_ctl->pages[0]);
}

static int io_ctl_check_crc(struct io_ctl *io_ctl, int index)
{
	u32 *tmp, val;
	u32 crc = ~(u32)0;
	unsigned offset = 0;

	if (!io_ctl->check_crcs) {
		io_ctl_map_page(io_ctl, 0);
		return 0;
	}

	if (index == 0)
		offset = sizeof(u32) * io_ctl->num_pages;

	tmp = kmap(io_ctl->pages[0]);
	tmp += index;
	val = *tmp;
	kunmap(io_ctl->pages[0]);

	io_ctl_map_page(io_ctl, 0);
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	crc = btrfs_csum_data(io_ctl->orig + offset, crc,
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			      PAGE_CACHE_SIZE - offset);
	btrfs_csum_final(crc, (char *)&crc);
	if (val != crc) {
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		printk_ratelimited(KERN_ERR "BTRFS: csum mismatch on free "
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				   "space cache\n");
		io_ctl_unmap_page(io_ctl);
		return -EIO;
	}

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	return 0;
}

static int io_ctl_add_entry(struct io_ctl *io_ctl, u64 offset, u64 bytes,
			    void *bitmap)
{
	struct btrfs_free_space_entry *entry;

	if (!io_ctl->cur)
		return -ENOSPC;

	entry = io_ctl->cur;
	entry->offset = cpu_to_le64(offset);
	entry->bytes = cpu_to_le64(bytes);
	entry->type = (bitmap) ? BTRFS_FREE_SPACE_BITMAP :
		BTRFS_FREE_SPACE_EXTENT;
	io_ctl->cur += sizeof(struct btrfs_free_space_entry);
	io_ctl->size -= sizeof(struct btrfs_free_space_entry);

	if (io_ctl->size >= sizeof(struct btrfs_free_space_entry))
		return 0;

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	io_ctl_set_crc(io_ctl, io_ctl->index - 1);
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	/* No more pages to map */
	if (io_ctl->index >= io_ctl->num_pages)
		return 0;

	/* map the next page */
	io_ctl_map_page(io_ctl, 1);
	return 0;
}

static int io_ctl_add_bitmap(struct io_ctl *io_ctl, void *bitmap)
{
	if (!io_ctl->cur)
		return -ENOSPC;

	/*
	 * If we aren't at the start of the current page, unmap this one and
	 * map the next one if there is any left.
	 */
	if (io_ctl->cur != io_ctl->orig) {
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		io_ctl_set_crc(io_ctl, io_ctl->index - 1);
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		if (io_ctl->index >= io_ctl->num_pages)
			return -ENOSPC;
		io_ctl_map_page(io_ctl, 0);
	}

	memcpy(io_ctl->cur, bitmap, PAGE_CACHE_SIZE);
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	io_ctl_set_crc(io_ctl, io_ctl->index - 1);
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	if (io_ctl->index < io_ctl->num_pages)
		io_ctl_map_page(io_ctl, 0);
	return 0;
}

static void io_ctl_zero_remaining_pages(struct io_ctl *io_ctl)
{
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	/*
	 * If we're not on the boundary we know we've modified the page and we
	 * need to crc the page.
	 */
	if (io_ctl->cur != io_ctl->orig)
		io_ctl_set_crc(io_ctl, io_ctl->index - 1);
	else
		io_ctl_unmap_page(io_ctl);
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	while (io_ctl->index < io_ctl->num_pages) {
		io_ctl_map_page(io_ctl, 1);
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		io_ctl_set_crc(io_ctl, io_ctl->index - 1);
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	}
}

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static int io_ctl_read_entry(struct io_ctl *io_ctl,
			    struct btrfs_free_space *entry, u8 *type)
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{
	struct btrfs_free_space_entry *e;
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	int ret;

	if (!io_ctl->cur) {
		ret = io_ctl_check_crc(io_ctl, io_ctl->index);
		if (ret)
			return ret;
	}
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	e = io_ctl->cur;
	entry->offset = le64_to_cpu(e->offset);
	entry->bytes = le64_to_cpu(e->bytes);
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	*type = e->type;
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	io_ctl->cur += sizeof(struct btrfs_free_space_entry);
	io_ctl->size -= sizeof(struct btrfs_free_space_entry);

	if (io_ctl->size >= sizeof(struct btrfs_free_space_entry))
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		return 0;
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	io_ctl_unmap_page(io_ctl);

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	return 0;
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}

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static int io_ctl_read_bitmap(struct io_ctl *io_ctl,
			      struct btrfs_free_space *entry)
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{
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	int ret;

	ret = io_ctl_check_crc(io_ctl, io_ctl->index);
	if (ret)
		return ret;

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	memcpy(entry->bitmap, io_ctl->cur, PAGE_CACHE_SIZE);
	io_ctl_unmap_page(io_ctl);
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	return 0;
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}

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/*
 * Since we attach pinned extents after the fact we can have contiguous sections
 * of free space that are split up in entries.  This poses a problem with the
 * tree logging stuff since it could have allocated across what appears to be 2
 * entries since we would have merged the entries when adding the pinned extents
 * back to the free space cache.  So run through the space cache that we just
 * loaded and merge contiguous entries.  This will make the log replay stuff not
 * blow up and it will make for nicer allocator behavior.
 */
static void merge_space_tree(struct btrfs_free_space_ctl *ctl)
{
	struct btrfs_free_space *e, *prev = NULL;
	struct rb_node *n;

again:
	spin_lock(&ctl->tree_lock);
	for (n = rb_first(&ctl->free_space_offset); n; n = rb_next(n)) {
		e = rb_entry(n, struct btrfs_free_space, offset_index);
		if (!prev)
			goto next;
		if (e->bitmap || prev->bitmap)
			goto next;
		if (prev->offset + prev->bytes == e->offset) {
			unlink_free_space(ctl, prev);
			unlink_free_space(ctl, e);
			prev->bytes += e->bytes;
			kmem_cache_free(btrfs_free_space_cachep, e);
			link_free_space(ctl, prev);
			prev = NULL;
			spin_unlock(&ctl->tree_lock);
			goto again;
		}
next:
		prev = e;
	}
	spin_unlock(&ctl->tree_lock);
}

638 639 640
static int __load_free_space_cache(struct btrfs_root *root, struct inode *inode,
				   struct btrfs_free_space_ctl *ctl,
				   struct btrfs_path *path, u64 offset)
641 642 643
{
	struct btrfs_free_space_header *header;
	struct extent_buffer *leaf;
644
	struct io_ctl io_ctl;
645
	struct btrfs_key key;
646
	struct btrfs_free_space *e, *n;
647 648 649 650
	struct list_head bitmaps;
	u64 num_entries;
	u64 num_bitmaps;
	u64 generation;
651
	u8 type;
652
	int ret = 0;
653 654 655 656

	INIT_LIST_HEAD(&bitmaps);

	/* Nothing in the space cache, goodbye */
657
	if (!i_size_read(inode))
658
		return 0;
659 660

	key.objectid = BTRFS_FREE_SPACE_OBJECTID;
661
	key.offset = offset;
662 663 664
	key.type = 0;

	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
665
	if (ret < 0)
666
		return 0;
667
	else if (ret > 0) {
668
		btrfs_release_path(path);
669
		return 0;
670 671
	}

672 673
	ret = -1;

674 675 676 677 678 679
	leaf = path->nodes[0];
	header = btrfs_item_ptr(leaf, path->slots[0],
				struct btrfs_free_space_header);
	num_entries = btrfs_free_space_entries(leaf, header);
	num_bitmaps = btrfs_free_space_bitmaps(leaf, header);
	generation = btrfs_free_space_generation(leaf, header);
680
	btrfs_release_path(path);
681

682 683 684 685 686 687 688
	if (!BTRFS_I(inode)->generation) {
		btrfs_info(root->fs_info,
			   "The free space cache file (%llu) is invalid. skip it\n",
			   offset);
		return 0;
	}

689
	if (BTRFS_I(inode)->generation != generation) {
690 691 692
		btrfs_err(root->fs_info,
			"free space inode generation (%llu) "
			"did not match free space cache generation (%llu)",
693
			BTRFS_I(inode)->generation, generation);
694
		return 0;
695 696 697
	}

	if (!num_entries)
698
		return 0;
699

700
	ret = io_ctl_init(&io_ctl, inode, root, 0);
701 702 703
	if (ret)
		return ret;

704
	ret = readahead_cache(inode);
705
	if (ret)
706 707
		goto out;

708 709 710
	ret = io_ctl_prepare_pages(&io_ctl, inode, 1);
	if (ret)
		goto out;
711

712 713 714 715
	ret = io_ctl_check_crc(&io_ctl, 0);
	if (ret)
		goto free_cache;

716 717 718
	ret = io_ctl_check_generation(&io_ctl, generation);
	if (ret)
		goto free_cache;
719

720 721 722 723
	while (num_entries) {
		e = kmem_cache_zalloc(btrfs_free_space_cachep,
				      GFP_NOFS);
		if (!e)
724 725
			goto free_cache;

726 727 728 729 730 731
		ret = io_ctl_read_entry(&io_ctl, e, &type);
		if (ret) {
			kmem_cache_free(btrfs_free_space_cachep, e);
			goto free_cache;
		}

732 733 734
		if (!e->bytes) {
			kmem_cache_free(btrfs_free_space_cachep, e);
			goto free_cache;
735
		}
736 737 738 739 740 741

		if (type == BTRFS_FREE_SPACE_EXTENT) {
			spin_lock(&ctl->tree_lock);
			ret = link_free_space(ctl, e);
			spin_unlock(&ctl->tree_lock);
			if (ret) {
742 743
				btrfs_err(root->fs_info,
					"Duplicate entries in free space cache, dumping");
744
				kmem_cache_free(btrfs_free_space_cachep, e);
745 746
				goto free_cache;
			}
747
		} else {
748
			ASSERT(num_bitmaps);
749 750 751 752 753
			num_bitmaps--;
			e->bitmap = kzalloc(PAGE_CACHE_SIZE, GFP_NOFS);
			if (!e->bitmap) {
				kmem_cache_free(
					btrfs_free_space_cachep, e);
754 755
				goto free_cache;
			}
756 757 758 759 760 761
			spin_lock(&ctl->tree_lock);
			ret = link_free_space(ctl, e);
			ctl->total_bitmaps++;
			ctl->op->recalc_thresholds(ctl);
			spin_unlock(&ctl->tree_lock);
			if (ret) {
762 763
				btrfs_err(root->fs_info,
					"Duplicate entries in free space cache, dumping");
764
				kmem_cache_free(btrfs_free_space_cachep, e);
765 766
				goto free_cache;
			}
767
			list_add_tail(&e->list, &bitmaps);
768 769
		}

770 771
		num_entries--;
	}
772

773 774
	io_ctl_unmap_page(&io_ctl);

775 776 777 778 779
	/*
	 * We add the bitmaps at the end of the entries in order that
	 * the bitmap entries are added to the cache.
	 */
	list_for_each_entry_safe(e, n, &bitmaps, list) {
780
		list_del_init(&e->list);
781 782 783
		ret = io_ctl_read_bitmap(&io_ctl, e);
		if (ret)
			goto free_cache;
784 785
	}

786
	io_ctl_drop_pages(&io_ctl);
787
	merge_space_tree(ctl);
788 789
	ret = 1;
out:
790
	io_ctl_free(&io_ctl);
791 792
	return ret;
free_cache:
793
	io_ctl_drop_pages(&io_ctl);
794
	__btrfs_remove_free_space_cache(ctl);
795 796 797
	goto out;
}

798 799
int load_free_space_cache(struct btrfs_fs_info *fs_info,
			  struct btrfs_block_group_cache *block_group)
J
Josef Bacik 已提交
800
{
801
	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
802 803 804
	struct btrfs_root *root = fs_info->tree_root;
	struct inode *inode;
	struct btrfs_path *path;
805
	int ret = 0;
806 807 808 809 810 811 812
	bool matched;
	u64 used = btrfs_block_group_used(&block_group->item);

	/*
	 * If this block group has been marked to be cleared for one reason or
	 * another then we can't trust the on disk cache, so just return.
	 */
813
	spin_lock(&block_group->lock);
814 815 816 817
	if (block_group->disk_cache_state != BTRFS_DC_WRITTEN) {
		spin_unlock(&block_group->lock);
		return 0;
	}
818
	spin_unlock(&block_group->lock);
819 820 821 822

	path = btrfs_alloc_path();
	if (!path)
		return 0;
823 824
	path->search_commit_root = 1;
	path->skip_locking = 1;
825 826 827 828 829 830 831

	inode = lookup_free_space_inode(root, block_group, path);
	if (IS_ERR(inode)) {
		btrfs_free_path(path);
		return 0;
	}

832 833 834 835
	/* We may have converted the inode and made the cache invalid. */
	spin_lock(&block_group->lock);
	if (block_group->disk_cache_state != BTRFS_DC_WRITTEN) {
		spin_unlock(&block_group->lock);
836
		btrfs_free_path(path);
837 838 839 840
		goto out;
	}
	spin_unlock(&block_group->lock);

841 842 843 844 845 846 847 848 849 850 851 852 853
	ret = __load_free_space_cache(fs_info->tree_root, inode, ctl,
				      path, block_group->key.objectid);
	btrfs_free_path(path);
	if (ret <= 0)
		goto out;

	spin_lock(&ctl->tree_lock);
	matched = (ctl->free_space == (block_group->key.offset - used -
				       block_group->bytes_super));
	spin_unlock(&ctl->tree_lock);

	if (!matched) {
		__btrfs_remove_free_space_cache(ctl);
854
		btrfs_warn(fs_info, "block group %llu has wrong amount of free space",
855
			block_group->key.objectid);
856 857 858 859 860 861 862 863
		ret = -1;
	}
out:
	if (ret < 0) {
		/* This cache is bogus, make sure it gets cleared */
		spin_lock(&block_group->lock);
		block_group->disk_cache_state = BTRFS_DC_CLEAR;
		spin_unlock(&block_group->lock);
864
		ret = 0;
865

866
		btrfs_warn(fs_info, "failed to load free space cache for block group %llu, rebuild it now",
867
			block_group->key.objectid);
868 869 870 871
	}

	iput(inode);
	return ret;
872 873
}

874 875 876 877 878 879
static noinline_for_stack
int write_cache_extent_entries(struct io_ctl *io_ctl,
			      struct btrfs_free_space_ctl *ctl,
			      struct btrfs_block_group_cache *block_group,
			      int *entries, int *bitmaps,
			      struct list_head *bitmap_list)
J
Josef Bacik 已提交
880
{
881
	int ret;
882 883
	struct btrfs_free_cluster *cluster = NULL;
	struct rb_node *node = rb_first(&ctl->free_space_offset);
884

885
	/* Get the cluster for this block_group if it exists */
886
	if (block_group && !list_empty(&block_group->cluster_list)) {
887 888 889
		cluster = list_entry(block_group->cluster_list.next,
				     struct btrfs_free_cluster,
				     block_group_list);
890
	}
891

892 893 894 895 896
	if (!node && cluster) {
		node = rb_first(&cluster->root);
		cluster = NULL;
	}

897 898 899
	/* Write out the extent entries */
	while (node) {
		struct btrfs_free_space *e;
J
Josef Bacik 已提交
900

901
		e = rb_entry(node, struct btrfs_free_space, offset_index);
902
		*entries += 1;
J
Josef Bacik 已提交
903

904
		ret = io_ctl_add_entry(io_ctl, e->offset, e->bytes,
905 906
				       e->bitmap);
		if (ret)
907
			goto fail;
908

909
		if (e->bitmap) {
910 911
			list_add_tail(&e->list, bitmap_list);
			*bitmaps += 1;
912
		}
913 914 915 916
		node = rb_next(node);
		if (!node && cluster) {
			node = rb_first(&cluster->root);
			cluster = NULL;
917
		}
918
	}
919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979
	return 0;
fail:
	return -ENOSPC;
}

static noinline_for_stack int
update_cache_item(struct btrfs_trans_handle *trans,
		  struct btrfs_root *root,
		  struct inode *inode,
		  struct btrfs_path *path, u64 offset,
		  int entries, int bitmaps)
{
	struct btrfs_key key;
	struct btrfs_free_space_header *header;
	struct extent_buffer *leaf;
	int ret;

	key.objectid = BTRFS_FREE_SPACE_OBJECTID;
	key.offset = offset;
	key.type = 0;

	ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
	if (ret < 0) {
		clear_extent_bit(&BTRFS_I(inode)->io_tree, 0, inode->i_size - 1,
				 EXTENT_DIRTY | EXTENT_DELALLOC, 0, 0, NULL,
				 GFP_NOFS);
		goto fail;
	}
	leaf = path->nodes[0];
	if (ret > 0) {
		struct btrfs_key found_key;
		ASSERT(path->slots[0]);
		path->slots[0]--;
		btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
		if (found_key.objectid != BTRFS_FREE_SPACE_OBJECTID ||
		    found_key.offset != offset) {
			clear_extent_bit(&BTRFS_I(inode)->io_tree, 0,
					 inode->i_size - 1,
					 EXTENT_DIRTY | EXTENT_DELALLOC, 0, 0,
					 NULL, GFP_NOFS);
			btrfs_release_path(path);
			goto fail;
		}
	}

	BTRFS_I(inode)->generation = trans->transid;
	header = btrfs_item_ptr(leaf, path->slots[0],
				struct btrfs_free_space_header);
	btrfs_set_free_space_entries(leaf, header, entries);
	btrfs_set_free_space_bitmaps(leaf, header, bitmaps);
	btrfs_set_free_space_generation(leaf, header, trans->transid);
	btrfs_mark_buffer_dirty(leaf);
	btrfs_release_path(path);

	return 0;

fail:
	return -1;
}

static noinline_for_stack int
980 981 982 983
write_pinned_extent_entries(struct btrfs_root *root,
			    struct btrfs_block_group_cache *block_group,
			    struct io_ctl *io_ctl,
			    int *entries)
984 985 986 987
{
	u64 start, extent_start, extent_end, len;
	struct extent_io_tree *unpin = NULL;
	int ret;
988

989 990 991
	if (!block_group)
		return 0;

992 993 994
	/*
	 * We want to add any pinned extents to our free space cache
	 * so we don't leak the space
995
	 *
996 997 998 999 1000
	 * We shouldn't have switched the pinned extents yet so this is the
	 * right one
	 */
	unpin = root->fs_info->pinned_extents;

1001
	start = block_group->key.objectid;
1002

1003
	while (start < block_group->key.objectid + block_group->key.offset) {
1004 1005
		ret = find_first_extent_bit(unpin, start,
					    &extent_start, &extent_end,
1006
					    EXTENT_DIRTY, NULL);
1007 1008
		if (ret)
			return 0;
J
Josef Bacik 已提交
1009

1010
		/* This pinned extent is out of our range */
1011
		if (extent_start >= block_group->key.objectid +
1012
		    block_group->key.offset)
1013
			return 0;
1014

1015 1016 1017 1018
		extent_start = max(extent_start, start);
		extent_end = min(block_group->key.objectid +
				 block_group->key.offset, extent_end + 1);
		len = extent_end - extent_start;
J
Josef Bacik 已提交
1019

1020 1021
		*entries += 1;
		ret = io_ctl_add_entry(io_ctl, extent_start, len, NULL);
1022
		if (ret)
1023
			return -ENOSPC;
J
Josef Bacik 已提交
1024

1025
		start = extent_end;
1026
	}
J
Josef Bacik 已提交
1027

1028 1029 1030 1031 1032 1033 1034 1035 1036
	return 0;
}

static noinline_for_stack int
write_bitmap_entries(struct io_ctl *io_ctl, struct list_head *bitmap_list)
{
	struct list_head *pos, *n;
	int ret;

J
Josef Bacik 已提交
1037
	/* Write out the bitmaps */
1038
	list_for_each_safe(pos, n, bitmap_list) {
J
Josef Bacik 已提交
1039 1040 1041
		struct btrfs_free_space *entry =
			list_entry(pos, struct btrfs_free_space, list);

1042
		ret = io_ctl_add_bitmap(io_ctl, entry->bitmap);
1043
		if (ret)
1044
			return -ENOSPC;
J
Josef Bacik 已提交
1045
		list_del_init(&entry->list);
1046 1047
	}

1048 1049
	return 0;
}
J
Josef Bacik 已提交
1050

1051 1052 1053
static int flush_dirty_cache(struct inode *inode)
{
	int ret;
1054

1055
	ret = btrfs_wait_ordered_range(inode, 0, (u64)-1);
1056
	if (ret)
1057 1058 1059
		clear_extent_bit(&BTRFS_I(inode)->io_tree, 0, inode->i_size - 1,
				 EXTENT_DIRTY | EXTENT_DELALLOC, 0, 0, NULL,
				 GFP_NOFS);
J
Josef Bacik 已提交
1060

1061
	return ret;
1062 1063 1064 1065 1066 1067 1068 1069 1070
}

static void noinline_for_stack
cleanup_write_cache_enospc(struct inode *inode,
			   struct io_ctl *io_ctl,
			   struct extent_state **cached_state,
			   struct list_head *bitmap_list)
{
	struct list_head *pos, *n;
1071

1072 1073 1074 1075
	list_for_each_safe(pos, n, bitmap_list) {
		struct btrfs_free_space *entry =
			list_entry(pos, struct btrfs_free_space, list);
		list_del_init(&entry->list);
J
Josef Bacik 已提交
1076
	}
1077 1078 1079 1080 1081
	io_ctl_drop_pages(io_ctl);
	unlock_extent_cached(&BTRFS_I(inode)->io_tree, 0,
			     i_size_read(inode) - 1, cached_state,
			     GFP_NOFS);
}
1082

1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103
/**
 * __btrfs_write_out_cache - write out cached info to an inode
 * @root - the root the inode belongs to
 * @ctl - the free space cache we are going to write out
 * @block_group - the block_group for this cache if it belongs to a block_group
 * @trans - the trans handle
 * @path - the path to use
 * @offset - the offset for the key we'll insert
 *
 * This function writes out a free space cache struct to disk for quick recovery
 * on mount.  This will return 0 if it was successfull in writing the cache out,
 * and -1 if it was not.
 */
static int __btrfs_write_out_cache(struct btrfs_root *root, struct inode *inode,
				   struct btrfs_free_space_ctl *ctl,
				   struct btrfs_block_group_cache *block_group,
				   struct btrfs_trans_handle *trans,
				   struct btrfs_path *path, u64 offset)
{
	struct extent_state *cached_state = NULL;
	struct io_ctl io_ctl;
1104
	LIST_HEAD(bitmap_list);
1105 1106 1107 1108 1109 1110 1111
	int entries = 0;
	int bitmaps = 0;
	int ret;

	if (!i_size_read(inode))
		return -1;

1112
	ret = io_ctl_init(&io_ctl, inode, root, 1);
1113 1114 1115
	if (ret)
		return -1;

1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129
	if (block_group && (block_group->flags & BTRFS_BLOCK_GROUP_DATA)) {
		down_write(&block_group->data_rwsem);
		spin_lock(&block_group->lock);
		if (block_group->delalloc_bytes) {
			block_group->disk_cache_state = BTRFS_DC_WRITTEN;
			spin_unlock(&block_group->lock);
			up_write(&block_group->data_rwsem);
			BTRFS_I(inode)->generation = 0;
			ret = 0;
			goto out;
		}
		spin_unlock(&block_group->lock);
	}

1130 1131 1132 1133 1134 1135 1136 1137
	/* Lock all pages first so we can lock the extent safely. */
	io_ctl_prepare_pages(&io_ctl, inode, 0);

	lock_extent_bits(&BTRFS_I(inode)->io_tree, 0, i_size_read(inode) - 1,
			 0, &cached_state);

	io_ctl_set_generation(&io_ctl, trans->transid);

1138
	/* Write out the extent entries in the free space cache */
1139 1140 1141 1142 1143 1144
	ret = write_cache_extent_entries(&io_ctl, ctl,
					 block_group, &entries, &bitmaps,
					 &bitmap_list);
	if (ret)
		goto out_nospc;

1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160
	/*
	 * Some spaces that are freed in the current transaction are pinned,
	 * they will be added into free space cache after the transaction is
	 * committed, we shouldn't lose them.
	 */
	ret = write_pinned_extent_entries(root, block_group, &io_ctl, &entries);
	if (ret)
		goto out_nospc;

	/* At last, we write out all the bitmaps. */
	ret = write_bitmap_entries(&io_ctl, &bitmap_list);
	if (ret)
		goto out_nospc;

	/* Zero out the rest of the pages just to make sure */
	io_ctl_zero_remaining_pages(&io_ctl);
1161

1162 1163 1164 1165
	/* Everything is written out, now we dirty the pages in the file. */
	ret = btrfs_dirty_pages(root, inode, io_ctl.pages, io_ctl.num_pages,
				0, i_size_read(inode), &cached_state);
	if (ret)
1166
		goto out_nospc;
1167

1168 1169
	if (block_group && (block_group->flags & BTRFS_BLOCK_GROUP_DATA))
		up_write(&block_group->data_rwsem);
1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181
	/*
	 * Release the pages and unlock the extent, we will flush
	 * them out later
	 */
	io_ctl_drop_pages(&io_ctl);

	unlock_extent_cached(&BTRFS_I(inode)->io_tree, 0,
			     i_size_read(inode) - 1, &cached_state, GFP_NOFS);

	/* Flush the dirty pages in the cache file. */
	ret = flush_dirty_cache(inode);
	if (ret)
1182 1183
		goto out;

1184 1185
	/* Update the cache item to tell everyone this cache file is valid. */
	ret = update_cache_item(trans, root, inode, path, offset,
1186
				entries, bitmaps);
1187
out:
1188
	io_ctl_free(&io_ctl);
1189
	if (ret) {
1190
		invalidate_inode_pages2(inode->i_mapping);
J
Josef Bacik 已提交
1191 1192 1193
		BTRFS_I(inode)->generation = 0;
	}
	btrfs_update_inode(trans, root, inode);
1194
	return ret;
1195 1196

out_nospc:
1197
	cleanup_write_cache_enospc(inode, &io_ctl, &cached_state, &bitmap_list);
1198 1199 1200 1201

	if (block_group && (block_group->flags & BTRFS_BLOCK_GROUP_DATA))
		up_write(&block_group->data_rwsem);

1202
	goto out;
1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220
}

int btrfs_write_out_cache(struct btrfs_root *root,
			  struct btrfs_trans_handle *trans,
			  struct btrfs_block_group_cache *block_group,
			  struct btrfs_path *path)
{
	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
	struct inode *inode;
	int ret = 0;

	root = root->fs_info->tree_root;

	spin_lock(&block_group->lock);
	if (block_group->disk_cache_state < BTRFS_DC_SETUP) {
		spin_unlock(&block_group->lock);
		return 0;
	}
1221 1222 1223 1224 1225 1226

	if (block_group->delalloc_bytes) {
		block_group->disk_cache_state = BTRFS_DC_WRITTEN;
		spin_unlock(&block_group->lock);
		return 0;
	}
1227 1228 1229 1230 1231 1232 1233 1234
	spin_unlock(&block_group->lock);

	inode = lookup_free_space_inode(root, block_group, path);
	if (IS_ERR(inode))
		return 0;

	ret = __btrfs_write_out_cache(root, inode, ctl, block_group, trans,
				      path, block_group->key.objectid);
1235
	if (ret) {
1236 1237 1238
		spin_lock(&block_group->lock);
		block_group->disk_cache_state = BTRFS_DC_ERROR;
		spin_unlock(&block_group->lock);
1239
		ret = 0;
1240
#ifdef DEBUG
1241 1242 1243
		btrfs_err(root->fs_info,
			"failed to write free space cache for block group %llu",
			block_group->key.objectid);
1244
#endif
1245 1246
	}

J
Josef Bacik 已提交
1247 1248 1249 1250
	iput(inode);
	return ret;
}

1251
static inline unsigned long offset_to_bit(u64 bitmap_start, u32 unit,
1252
					  u64 offset)
J
Josef Bacik 已提交
1253
{
1254
	ASSERT(offset >= bitmap_start);
1255
	offset -= bitmap_start;
1256
	return (unsigned long)(div_u64(offset, unit));
1257
}
J
Josef Bacik 已提交
1258

1259
static inline unsigned long bytes_to_bits(u64 bytes, u32 unit)
1260
{
1261
	return (unsigned long)(div_u64(bytes, unit));
1262
}
J
Josef Bacik 已提交
1263

1264
static inline u64 offset_to_bitmap(struct btrfs_free_space_ctl *ctl,
1265 1266 1267 1268
				   u64 offset)
{
	u64 bitmap_start;
	u64 bytes_per_bitmap;
J
Josef Bacik 已提交
1269

1270 1271
	bytes_per_bitmap = BITS_PER_BITMAP * ctl->unit;
	bitmap_start = offset - ctl->start;
1272 1273
	bitmap_start = div64_u64(bitmap_start, bytes_per_bitmap);
	bitmap_start *= bytes_per_bitmap;
1274
	bitmap_start += ctl->start;
J
Josef Bacik 已提交
1275

1276
	return bitmap_start;
J
Josef Bacik 已提交
1277 1278
}

1279 1280
static int tree_insert_offset(struct rb_root *root, u64 offset,
			      struct rb_node *node, int bitmap)
J
Josef Bacik 已提交
1281 1282 1283 1284 1285 1286 1287
{
	struct rb_node **p = &root->rb_node;
	struct rb_node *parent = NULL;
	struct btrfs_free_space *info;

	while (*p) {
		parent = *p;
1288
		info = rb_entry(parent, struct btrfs_free_space, offset_index);
J
Josef Bacik 已提交
1289

1290
		if (offset < info->offset) {
J
Josef Bacik 已提交
1291
			p = &(*p)->rb_left;
1292
		} else if (offset > info->offset) {
J
Josef Bacik 已提交
1293
			p = &(*p)->rb_right;
1294 1295 1296 1297 1298 1299 1300 1301 1302 1303 1304 1305 1306 1307 1308
		} else {
			/*
			 * we could have a bitmap entry and an extent entry
			 * share the same offset.  If this is the case, we want
			 * the extent entry to always be found first if we do a
			 * linear search through the tree, since we want to have
			 * the quickest allocation time, and allocating from an
			 * extent is faster than allocating from a bitmap.  So
			 * if we're inserting a bitmap and we find an entry at
			 * this offset, we want to go right, or after this entry
			 * logically.  If we are inserting an extent and we've
			 * found a bitmap, we want to go left, or before
			 * logically.
			 */
			if (bitmap) {
1309 1310 1311 1312
				if (info->bitmap) {
					WARN_ON_ONCE(1);
					return -EEXIST;
				}
1313 1314
				p = &(*p)->rb_right;
			} else {
1315 1316 1317 1318
				if (!info->bitmap) {
					WARN_ON_ONCE(1);
					return -EEXIST;
				}
1319 1320 1321
				p = &(*p)->rb_left;
			}
		}
J
Josef Bacik 已提交
1322 1323 1324 1325 1326 1327 1328 1329 1330
	}

	rb_link_node(node, parent, p);
	rb_insert_color(node, root);

	return 0;
}

/*
J
Josef Bacik 已提交
1331 1332
 * searches the tree for the given offset.
 *
1333 1334 1335
 * fuzzy - If this is set, then we are trying to make an allocation, and we just
 * want a section that has at least bytes size and comes at or after the given
 * offset.
J
Josef Bacik 已提交
1336
 */
1337
static struct btrfs_free_space *
1338
tree_search_offset(struct btrfs_free_space_ctl *ctl,
1339
		   u64 offset, int bitmap_only, int fuzzy)
J
Josef Bacik 已提交
1340
{
1341
	struct rb_node *n = ctl->free_space_offset.rb_node;
1342 1343 1344 1345 1346 1347 1348 1349
	struct btrfs_free_space *entry, *prev = NULL;

	/* find entry that is closest to the 'offset' */
	while (1) {
		if (!n) {
			entry = NULL;
			break;
		}
J
Josef Bacik 已提交
1350 1351

		entry = rb_entry(n, struct btrfs_free_space, offset_index);
1352
		prev = entry;
J
Josef Bacik 已提交
1353

1354
		if (offset < entry->offset)
J
Josef Bacik 已提交
1355
			n = n->rb_left;
1356
		else if (offset > entry->offset)
J
Josef Bacik 已提交
1357
			n = n->rb_right;
1358
		else
J
Josef Bacik 已提交
1359 1360 1361
			break;
	}

1362 1363 1364 1365 1366
	if (bitmap_only) {
		if (!entry)
			return NULL;
		if (entry->bitmap)
			return entry;
J
Josef Bacik 已提交
1367

1368 1369 1370 1371 1372 1373 1374 1375 1376 1377
		/*
		 * bitmap entry and extent entry may share same offset,
		 * in that case, bitmap entry comes after extent entry.
		 */
		n = rb_next(n);
		if (!n)
			return NULL;
		entry = rb_entry(n, struct btrfs_free_space, offset_index);
		if (entry->offset != offset)
			return NULL;
J
Josef Bacik 已提交
1378

1379 1380 1381 1382
		WARN_ON(!entry->bitmap);
		return entry;
	} else if (entry) {
		if (entry->bitmap) {
J
Josef Bacik 已提交
1383
			/*
1384 1385
			 * if previous extent entry covers the offset,
			 * we should return it instead of the bitmap entry
J
Josef Bacik 已提交
1386
			 */
1387 1388
			n = rb_prev(&entry->offset_index);
			if (n) {
1389 1390
				prev = rb_entry(n, struct btrfs_free_space,
						offset_index);
1391 1392 1393
				if (!prev->bitmap &&
				    prev->offset + prev->bytes > offset)
					entry = prev;
J
Josef Bacik 已提交
1394
			}
1395 1396 1397 1398 1399 1400 1401 1402 1403 1404 1405 1406 1407 1408
		}
		return entry;
	}

	if (!prev)
		return NULL;

	/* find last entry before the 'offset' */
	entry = prev;
	if (entry->offset > offset) {
		n = rb_prev(&entry->offset_index);
		if (n) {
			entry = rb_entry(n, struct btrfs_free_space,
					offset_index);
1409
			ASSERT(entry->offset <= offset);
J
Josef Bacik 已提交
1410
		} else {
1411 1412 1413 1414
			if (fuzzy)
				return entry;
			else
				return NULL;
J
Josef Bacik 已提交
1415 1416 1417
		}
	}

1418
	if (entry->bitmap) {
1419 1420
		n = rb_prev(&entry->offset_index);
		if (n) {
1421 1422
			prev = rb_entry(n, struct btrfs_free_space,
					offset_index);
1423 1424 1425
			if (!prev->bitmap &&
			    prev->offset + prev->bytes > offset)
				return prev;
1426
		}
1427
		if (entry->offset + BITS_PER_BITMAP * ctl->unit > offset)
1428 1429 1430 1431 1432 1433 1434 1435 1436 1437
			return entry;
	} else if (entry->offset + entry->bytes > offset)
		return entry;

	if (!fuzzy)
		return NULL;

	while (1) {
		if (entry->bitmap) {
			if (entry->offset + BITS_PER_BITMAP *
1438
			    ctl->unit > offset)
1439 1440 1441 1442 1443 1444 1445 1446 1447 1448 1449 1450
				break;
		} else {
			if (entry->offset + entry->bytes > offset)
				break;
		}

		n = rb_next(&entry->offset_index);
		if (!n)
			return NULL;
		entry = rb_entry(n, struct btrfs_free_space, offset_index);
	}
	return entry;
J
Josef Bacik 已提交
1451 1452
}

1453
static inline void
1454
__unlink_free_space(struct btrfs_free_space_ctl *ctl,
1455
		    struct btrfs_free_space *info)
J
Josef Bacik 已提交
1456
{
1457 1458
	rb_erase(&info->offset_index, &ctl->free_space_offset);
	ctl->free_extents--;
1459 1460
}

1461
static void unlink_free_space(struct btrfs_free_space_ctl *ctl,
1462 1463
			      struct btrfs_free_space *info)
{
1464 1465
	__unlink_free_space(ctl, info);
	ctl->free_space -= info->bytes;
J
Josef Bacik 已提交
1466 1467
}

1468
static int link_free_space(struct btrfs_free_space_ctl *ctl,
J
Josef Bacik 已提交
1469 1470 1471 1472
			   struct btrfs_free_space *info)
{
	int ret = 0;

1473
	ASSERT(info->bytes || info->bitmap);
1474
	ret = tree_insert_offset(&ctl->free_space_offset, info->offset,
1475
				 &info->offset_index, (info->bitmap != NULL));
J
Josef Bacik 已提交
1476 1477 1478
	if (ret)
		return ret;

1479 1480
	ctl->free_space += info->bytes;
	ctl->free_extents++;
1481 1482 1483
	return ret;
}

1484
static void recalculate_thresholds(struct btrfs_free_space_ctl *ctl)
1485
{
1486
	struct btrfs_block_group_cache *block_group = ctl->private;
1487 1488 1489
	u64 max_bytes;
	u64 bitmap_bytes;
	u64 extent_bytes;
1490
	u64 size = block_group->key.offset;
1491
	u64 bytes_per_bg = BITS_PER_BITMAP * ctl->unit;
1492 1493
	int max_bitmaps = div64_u64(size + bytes_per_bg - 1, bytes_per_bg);

1494 1495
	max_bitmaps = max(max_bitmaps, 1);

1496
	ASSERT(ctl->total_bitmaps <= max_bitmaps);
1497 1498 1499 1500 1501 1502

	/*
	 * The goal is to keep the total amount of memory used per 1gb of space
	 * at or below 32k, so we need to adjust how much memory we allow to be
	 * used by extent based free space tracking
	 */
1503 1504 1505 1506 1507
	if (size < 1024 * 1024 * 1024)
		max_bytes = MAX_CACHE_BYTES_PER_GIG;
	else
		max_bytes = MAX_CACHE_BYTES_PER_GIG *
			div64_u64(size, 1024 * 1024 * 1024);
1508

1509 1510 1511 1512 1513
	/*
	 * we want to account for 1 more bitmap than what we have so we can make
	 * sure we don't go over our overall goal of MAX_CACHE_BYTES_PER_GIG as
	 * we add more bitmaps.
	 */
1514
	bitmap_bytes = (ctl->total_bitmaps + 1) * PAGE_CACHE_SIZE;
1515

1516
	if (bitmap_bytes >= max_bytes) {
1517
		ctl->extents_thresh = 0;
1518 1519
		return;
	}
1520

1521 1522 1523 1524 1525 1526
	/*
	 * we want the extent entry threshold to always be at most 1/2 the maxw
	 * bytes we can have, or whatever is less than that.
	 */
	extent_bytes = max_bytes - bitmap_bytes;
	extent_bytes = min_t(u64, extent_bytes, div64_u64(max_bytes, 2));
1527

1528
	ctl->extents_thresh =
1529
		div64_u64(extent_bytes, (sizeof(struct btrfs_free_space)));
1530 1531
}

1532 1533 1534
static inline void __bitmap_clear_bits(struct btrfs_free_space_ctl *ctl,
				       struct btrfs_free_space *info,
				       u64 offset, u64 bytes)
1535
{
L
Li Zefan 已提交
1536
	unsigned long start, count;
1537

1538 1539
	start = offset_to_bit(info->offset, ctl->unit, offset);
	count = bytes_to_bits(bytes, ctl->unit);
1540
	ASSERT(start + count <= BITS_PER_BITMAP);
1541

L
Li Zefan 已提交
1542
	bitmap_clear(info->bitmap, start, count);
1543 1544

	info->bytes -= bytes;
1545 1546 1547 1548 1549 1550 1551
}

static void bitmap_clear_bits(struct btrfs_free_space_ctl *ctl,
			      struct btrfs_free_space *info, u64 offset,
			      u64 bytes)
{
	__bitmap_clear_bits(ctl, info, offset, bytes);
1552
	ctl->free_space -= bytes;
1553 1554
}

1555
static void bitmap_set_bits(struct btrfs_free_space_ctl *ctl,
J
Josef Bacik 已提交
1556 1557
			    struct btrfs_free_space *info, u64 offset,
			    u64 bytes)
1558
{
L
Li Zefan 已提交
1559
	unsigned long start, count;
1560

1561 1562
	start = offset_to_bit(info->offset, ctl->unit, offset);
	count = bytes_to_bits(bytes, ctl->unit);
1563
	ASSERT(start + count <= BITS_PER_BITMAP);
1564

L
Li Zefan 已提交
1565
	bitmap_set(info->bitmap, start, count);
1566 1567

	info->bytes += bytes;
1568
	ctl->free_space += bytes;
1569 1570
}

1571 1572 1573 1574
/*
 * If we can not find suitable extent, we will use bytes to record
 * the size of the max extent.
 */
1575
static int search_bitmap(struct btrfs_free_space_ctl *ctl,
1576 1577 1578 1579
			 struct btrfs_free_space *bitmap_info, u64 *offset,
			 u64 *bytes)
{
	unsigned long found_bits = 0;
1580
	unsigned long max_bits = 0;
1581 1582
	unsigned long bits, i;
	unsigned long next_zero;
1583
	unsigned long extent_bits;
1584

1585
	i = offset_to_bit(bitmap_info->offset, ctl->unit,
1586
			  max_t(u64, *offset, bitmap_info->offset));
1587
	bits = bytes_to_bits(*bytes, ctl->unit);
1588

1589
	for_each_set_bit_from(i, bitmap_info->bitmap, BITS_PER_BITMAP) {
1590 1591
		next_zero = find_next_zero_bit(bitmap_info->bitmap,
					       BITS_PER_BITMAP, i);
1592 1593 1594
		extent_bits = next_zero - i;
		if (extent_bits >= bits) {
			found_bits = extent_bits;
1595
			break;
1596 1597
		} else if (extent_bits > max_bits) {
			max_bits = extent_bits;
1598 1599 1600 1601 1602
		}
		i = next_zero;
	}

	if (found_bits) {
1603 1604
		*offset = (u64)(i * ctl->unit) + bitmap_info->offset;
		*bytes = (u64)(found_bits) * ctl->unit;
1605 1606 1607
		return 0;
	}

1608
	*bytes = (u64)(max_bits) * ctl->unit;
1609 1610 1611
	return -1;
}

1612
/* Cache the size of the max extent in bytes */
1613
static struct btrfs_free_space *
D
David Woodhouse 已提交
1614
find_free_space(struct btrfs_free_space_ctl *ctl, u64 *offset, u64 *bytes,
1615
		unsigned long align, u64 *max_extent_size)
1616 1617 1618
{
	struct btrfs_free_space *entry;
	struct rb_node *node;
D
David Woodhouse 已提交
1619 1620
	u64 tmp;
	u64 align_off;
1621 1622
	int ret;

1623
	if (!ctl->free_space_offset.rb_node)
1624
		goto out;
1625

1626
	entry = tree_search_offset(ctl, offset_to_bitmap(ctl, *offset), 0, 1);
1627
	if (!entry)
1628
		goto out;
1629 1630 1631

	for (node = &entry->offset_index; node; node = rb_next(node)) {
		entry = rb_entry(node, struct btrfs_free_space, offset_index);
1632 1633 1634
		if (entry->bytes < *bytes) {
			if (entry->bytes > *max_extent_size)
				*max_extent_size = entry->bytes;
1635
			continue;
1636
		}
1637

D
David Woodhouse 已提交
1638 1639 1640 1641
		/* make sure the space returned is big enough
		 * to match our requested alignment
		 */
		if (*bytes >= align) {
1642
			tmp = entry->offset - ctl->start + align - 1;
D
David Woodhouse 已提交
1643 1644 1645 1646 1647 1648 1649 1650
			do_div(tmp, align);
			tmp = tmp * align + ctl->start;
			align_off = tmp - entry->offset;
		} else {
			align_off = 0;
			tmp = entry->offset;
		}

1651 1652 1653
		if (entry->bytes < *bytes + align_off) {
			if (entry->bytes > *max_extent_size)
				*max_extent_size = entry->bytes;
D
David Woodhouse 已提交
1654
			continue;
1655
		}
D
David Woodhouse 已提交
1656

1657
		if (entry->bitmap) {
1658 1659 1660
			u64 size = *bytes;

			ret = search_bitmap(ctl, entry, &tmp, &size);
D
David Woodhouse 已提交
1661 1662
			if (!ret) {
				*offset = tmp;
1663
				*bytes = size;
1664
				return entry;
1665 1666
			} else if (size > *max_extent_size) {
				*max_extent_size = size;
D
David Woodhouse 已提交
1667
			}
1668 1669 1670
			continue;
		}

D
David Woodhouse 已提交
1671 1672
		*offset = tmp;
		*bytes = entry->bytes - align_off;
1673 1674
		return entry;
	}
1675
out:
1676 1677 1678
	return NULL;
}

1679
static void add_new_bitmap(struct btrfs_free_space_ctl *ctl,
1680 1681
			   struct btrfs_free_space *info, u64 offset)
{
1682
	info->offset = offset_to_bitmap(ctl, offset);
J
Josef Bacik 已提交
1683
	info->bytes = 0;
1684
	INIT_LIST_HEAD(&info->list);
1685 1686
	link_free_space(ctl, info);
	ctl->total_bitmaps++;
1687

1688
	ctl->op->recalc_thresholds(ctl);
1689 1690
}

1691
static void free_bitmap(struct btrfs_free_space_ctl *ctl,
1692 1693
			struct btrfs_free_space *bitmap_info)
{
1694
	unlink_free_space(ctl, bitmap_info);
1695
	kfree(bitmap_info->bitmap);
1696
	kmem_cache_free(btrfs_free_space_cachep, bitmap_info);
1697 1698
	ctl->total_bitmaps--;
	ctl->op->recalc_thresholds(ctl);
1699 1700
}

1701
static noinline int remove_from_bitmap(struct btrfs_free_space_ctl *ctl,
1702 1703 1704 1705
			      struct btrfs_free_space *bitmap_info,
			      u64 *offset, u64 *bytes)
{
	u64 end;
1706 1707
	u64 search_start, search_bytes;
	int ret;
1708 1709

again:
1710
	end = bitmap_info->offset + (u64)(BITS_PER_BITMAP * ctl->unit) - 1;
1711

1712
	/*
1713 1714 1715 1716
	 * We need to search for bits in this bitmap.  We could only cover some
	 * of the extent in this bitmap thanks to how we add space, so we need
	 * to search for as much as it as we can and clear that amount, and then
	 * go searching for the next bit.
1717 1718
	 */
	search_start = *offset;
1719
	search_bytes = ctl->unit;
1720
	search_bytes = min(search_bytes, end - search_start + 1);
1721
	ret = search_bitmap(ctl, bitmap_info, &search_start, &search_bytes);
1722 1723
	if (ret < 0 || search_start != *offset)
		return -EINVAL;
1724

1725 1726 1727 1728 1729 1730 1731 1732 1733
	/* We may have found more bits than what we need */
	search_bytes = min(search_bytes, *bytes);

	/* Cannot clear past the end of the bitmap */
	search_bytes = min(search_bytes, end - search_start + 1);

	bitmap_clear_bits(ctl, bitmap_info, search_start, search_bytes);
	*offset += search_bytes;
	*bytes -= search_bytes;
1734 1735

	if (*bytes) {
1736
		struct rb_node *next = rb_next(&bitmap_info->offset_index);
1737
		if (!bitmap_info->bytes)
1738
			free_bitmap(ctl, bitmap_info);
1739

1740 1741 1742 1743 1744
		/*
		 * no entry after this bitmap, but we still have bytes to
		 * remove, so something has gone wrong.
		 */
		if (!next)
1745 1746
			return -EINVAL;

1747 1748 1749 1750 1751 1752 1753
		bitmap_info = rb_entry(next, struct btrfs_free_space,
				       offset_index);

		/*
		 * if the next entry isn't a bitmap we need to return to let the
		 * extent stuff do its work.
		 */
1754 1755 1756
		if (!bitmap_info->bitmap)
			return -EAGAIN;

1757 1758 1759 1760 1761 1762 1763
		/*
		 * Ok the next item is a bitmap, but it may not actually hold
		 * the information for the rest of this free space stuff, so
		 * look for it, and if we don't find it return so we can try
		 * everything over again.
		 */
		search_start = *offset;
1764
		search_bytes = ctl->unit;
1765
		ret = search_bitmap(ctl, bitmap_info, &search_start,
1766 1767 1768 1769
				    &search_bytes);
		if (ret < 0 || search_start != *offset)
			return -EAGAIN;

1770
		goto again;
1771
	} else if (!bitmap_info->bytes)
1772
		free_bitmap(ctl, bitmap_info);
1773 1774 1775 1776

	return 0;
}

J
Josef Bacik 已提交
1777 1778 1779 1780 1781 1782 1783 1784 1785 1786 1787 1788 1789 1790 1791 1792 1793
static u64 add_bytes_to_bitmap(struct btrfs_free_space_ctl *ctl,
			       struct btrfs_free_space *info, u64 offset,
			       u64 bytes)
{
	u64 bytes_to_set = 0;
	u64 end;

	end = info->offset + (u64)(BITS_PER_BITMAP * ctl->unit);

	bytes_to_set = min(end - offset, bytes);

	bitmap_set_bits(ctl, info, offset, bytes_to_set);

	return bytes_to_set;

}

1794 1795
static bool use_bitmap(struct btrfs_free_space_ctl *ctl,
		      struct btrfs_free_space *info)
1796
{
1797
	struct btrfs_block_group_cache *block_group = ctl->private;
1798 1799 1800 1801 1802

	/*
	 * If we are below the extents threshold then we can add this as an
	 * extent, and don't have to deal with the bitmap
	 */
1803
	if (ctl->free_extents < ctl->extents_thresh) {
1804 1805 1806 1807 1808 1809 1810 1811
		/*
		 * If this block group has some small extents we don't want to
		 * use up all of our free slots in the cache with them, we want
		 * to reserve them to larger extents, however if we have plent
		 * of cache left then go ahead an dadd them, no sense in adding
		 * the overhead of a bitmap if we don't have to.
		 */
		if (info->bytes <= block_group->sectorsize * 4) {
1812 1813
			if (ctl->free_extents * 2 <= ctl->extents_thresh)
				return false;
1814
		} else {
1815
			return false;
1816 1817
		}
	}
1818 1819

	/*
1820 1821 1822 1823 1824 1825
	 * The original block groups from mkfs can be really small, like 8
	 * megabytes, so don't bother with a bitmap for those entries.  However
	 * some block groups can be smaller than what a bitmap would cover but
	 * are still large enough that they could overflow the 32k memory limit,
	 * so allow those block groups to still be allowed to have a bitmap
	 * entry.
1826
	 */
1827
	if (((BITS_PER_BITMAP * ctl->unit) >> 1) > block_group->key.offset)
1828 1829 1830 1831 1832
		return false;

	return true;
}

J
Josef Bacik 已提交
1833 1834 1835 1836 1837
static struct btrfs_free_space_op free_space_op = {
	.recalc_thresholds	= recalculate_thresholds,
	.use_bitmap		= use_bitmap,
};

1838 1839 1840 1841
static int insert_into_bitmap(struct btrfs_free_space_ctl *ctl,
			      struct btrfs_free_space *info)
{
	struct btrfs_free_space *bitmap_info;
J
Josef Bacik 已提交
1842
	struct btrfs_block_group_cache *block_group = NULL;
1843
	int added = 0;
J
Josef Bacik 已提交
1844
	u64 bytes, offset, bytes_added;
1845
	int ret;
1846 1847 1848 1849

	bytes = info->bytes;
	offset = info->offset;

1850 1851 1852
	if (!ctl->op->use_bitmap(ctl, info))
		return 0;

J
Josef Bacik 已提交
1853 1854
	if (ctl->op == &free_space_op)
		block_group = ctl->private;
1855
again:
J
Josef Bacik 已提交
1856 1857 1858 1859 1860 1861 1862 1863 1864 1865 1866 1867 1868 1869 1870 1871 1872
	/*
	 * Since we link bitmaps right into the cluster we need to see if we
	 * have a cluster here, and if so and it has our bitmap we need to add
	 * the free space to that bitmap.
	 */
	if (block_group && !list_empty(&block_group->cluster_list)) {
		struct btrfs_free_cluster *cluster;
		struct rb_node *node;
		struct btrfs_free_space *entry;

		cluster = list_entry(block_group->cluster_list.next,
				     struct btrfs_free_cluster,
				     block_group_list);
		spin_lock(&cluster->lock);
		node = rb_first(&cluster->root);
		if (!node) {
			spin_unlock(&cluster->lock);
1873
			goto no_cluster_bitmap;
J
Josef Bacik 已提交
1874 1875 1876 1877 1878
		}

		entry = rb_entry(node, struct btrfs_free_space, offset_index);
		if (!entry->bitmap) {
			spin_unlock(&cluster->lock);
1879
			goto no_cluster_bitmap;
J
Josef Bacik 已提交
1880 1881 1882 1883 1884 1885 1886 1887 1888 1889 1890 1891 1892 1893
		}

		if (entry->offset == offset_to_bitmap(ctl, offset)) {
			bytes_added = add_bytes_to_bitmap(ctl, entry,
							  offset, bytes);
			bytes -= bytes_added;
			offset += bytes_added;
		}
		spin_unlock(&cluster->lock);
		if (!bytes) {
			ret = 1;
			goto out;
		}
	}
1894 1895

no_cluster_bitmap:
1896
	bitmap_info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
1897 1898
					 1, 0);
	if (!bitmap_info) {
1899
		ASSERT(added == 0);
1900 1901 1902
		goto new_bitmap;
	}

J
Josef Bacik 已提交
1903 1904 1905 1906
	bytes_added = add_bytes_to_bitmap(ctl, bitmap_info, offset, bytes);
	bytes -= bytes_added;
	offset += bytes_added;
	added = 0;
1907 1908 1909 1910 1911 1912 1913 1914 1915

	if (!bytes) {
		ret = 1;
		goto out;
	} else
		goto again;

new_bitmap:
	if (info && info->bitmap) {
1916
		add_new_bitmap(ctl, info, offset);
1917 1918 1919 1920
		added = 1;
		info = NULL;
		goto again;
	} else {
1921
		spin_unlock(&ctl->tree_lock);
1922 1923 1924

		/* no pre-allocated info, allocate a new one */
		if (!info) {
1925 1926
			info = kmem_cache_zalloc(btrfs_free_space_cachep,
						 GFP_NOFS);
1927
			if (!info) {
1928
				spin_lock(&ctl->tree_lock);
1929 1930 1931 1932 1933 1934 1935
				ret = -ENOMEM;
				goto out;
			}
		}

		/* allocate the bitmap */
		info->bitmap = kzalloc(PAGE_CACHE_SIZE, GFP_NOFS);
1936
		spin_lock(&ctl->tree_lock);
1937 1938 1939 1940 1941 1942 1943 1944 1945 1946 1947
		if (!info->bitmap) {
			ret = -ENOMEM;
			goto out;
		}
		goto again;
	}

out:
	if (info) {
		if (info->bitmap)
			kfree(info->bitmap);
1948
		kmem_cache_free(btrfs_free_space_cachep, info);
1949
	}
J
Josef Bacik 已提交
1950 1951 1952 1953

	return ret;
}

1954
static bool try_merge_free_space(struct btrfs_free_space_ctl *ctl,
1955
			  struct btrfs_free_space *info, bool update_stat)
J
Josef Bacik 已提交
1956
{
1957 1958 1959 1960 1961
	struct btrfs_free_space *left_info;
	struct btrfs_free_space *right_info;
	bool merged = false;
	u64 offset = info->offset;
	u64 bytes = info->bytes;
1962

J
Josef Bacik 已提交
1963 1964 1965 1966 1967
	/*
	 * first we want to see if there is free space adjacent to the range we
	 * are adding, if there is remove that struct and add a new one to
	 * cover the entire range
	 */
1968
	right_info = tree_search_offset(ctl, offset + bytes, 0, 0);
1969 1970 1971 1972
	if (right_info && rb_prev(&right_info->offset_index))
		left_info = rb_entry(rb_prev(&right_info->offset_index),
				     struct btrfs_free_space, offset_index);
	else
1973
		left_info = tree_search_offset(ctl, offset - 1, 0, 0);
J
Josef Bacik 已提交
1974

1975
	if (right_info && !right_info->bitmap) {
1976
		if (update_stat)
1977
			unlink_free_space(ctl, right_info);
1978
		else
1979
			__unlink_free_space(ctl, right_info);
1980
		info->bytes += right_info->bytes;
1981
		kmem_cache_free(btrfs_free_space_cachep, right_info);
1982
		merged = true;
J
Josef Bacik 已提交
1983 1984
	}

1985 1986
	if (left_info && !left_info->bitmap &&
	    left_info->offset + left_info->bytes == offset) {
1987
		if (update_stat)
1988
			unlink_free_space(ctl, left_info);
1989
		else
1990
			__unlink_free_space(ctl, left_info);
1991 1992
		info->offset = left_info->offset;
		info->bytes += left_info->bytes;
1993
		kmem_cache_free(btrfs_free_space_cachep, left_info);
1994
		merged = true;
J
Josef Bacik 已提交
1995 1996
	}

1997 1998 1999
	return merged;
}

2000 2001
int __btrfs_add_free_space(struct btrfs_free_space_ctl *ctl,
			   u64 offset, u64 bytes)
2002 2003 2004 2005
{
	struct btrfs_free_space *info;
	int ret = 0;

2006
	info = kmem_cache_zalloc(btrfs_free_space_cachep, GFP_NOFS);
2007 2008 2009 2010 2011 2012
	if (!info)
		return -ENOMEM;

	info->offset = offset;
	info->bytes = bytes;

2013
	spin_lock(&ctl->tree_lock);
2014

2015
	if (try_merge_free_space(ctl, info, true))
2016 2017 2018 2019 2020 2021 2022
		goto link;

	/*
	 * There was no extent directly to the left or right of this new
	 * extent then we know we're going to have to allocate a new extent, so
	 * before we do that see if we need to drop this into a bitmap
	 */
2023
	ret = insert_into_bitmap(ctl, info);
2024 2025 2026 2027 2028 2029 2030
	if (ret < 0) {
		goto out;
	} else if (ret) {
		ret = 0;
		goto out;
	}
link:
2031
	ret = link_free_space(ctl, info);
J
Josef Bacik 已提交
2032
	if (ret)
2033
		kmem_cache_free(btrfs_free_space_cachep, info);
2034
out:
2035
	spin_unlock(&ctl->tree_lock);
2036

J
Josef Bacik 已提交
2037
	if (ret) {
2038
		printk(KERN_CRIT "BTRFS: unable to add free space :%d\n", ret);
2039
		ASSERT(ret != -EEXIST);
J
Josef Bacik 已提交
2040 2041 2042 2043 2044
	}

	return ret;
}

2045 2046
int btrfs_remove_free_space(struct btrfs_block_group_cache *block_group,
			    u64 offset, u64 bytes)
J
Josef Bacik 已提交
2047
{
2048
	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
J
Josef Bacik 已提交
2049
	struct btrfs_free_space *info;
2050 2051
	int ret;
	bool re_search = false;
J
Josef Bacik 已提交
2052

2053
	spin_lock(&ctl->tree_lock);
2054

2055
again:
2056
	ret = 0;
2057 2058 2059
	if (!bytes)
		goto out_lock;

2060
	info = tree_search_offset(ctl, offset, 0, 0);
2061
	if (!info) {
2062 2063 2064 2065
		/*
		 * oops didn't find an extent that matched the space we wanted
		 * to remove, look for a bitmap instead
		 */
2066
		info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
2067 2068
					  1, 0);
		if (!info) {
2069 2070 2071 2072
			/*
			 * If we found a partial bit of our free space in a
			 * bitmap but then couldn't find the other part this may
			 * be a problem, so WARN about it.
2073
			 */
2074
			WARN_ON(re_search);
2075 2076
			goto out_lock;
		}
2077 2078
	}

2079
	re_search = false;
2080
	if (!info->bitmap) {
2081
		unlink_free_space(ctl, info);
2082 2083 2084 2085 2086 2087 2088 2089 2090 2091 2092
		if (offset == info->offset) {
			u64 to_free = min(bytes, info->bytes);

			info->bytes -= to_free;
			info->offset += to_free;
			if (info->bytes) {
				ret = link_free_space(ctl, info);
				WARN_ON(ret);
			} else {
				kmem_cache_free(btrfs_free_space_cachep, info);
			}
J
Josef Bacik 已提交
2093

2094 2095 2096 2097 2098
			offset += to_free;
			bytes -= to_free;
			goto again;
		} else {
			u64 old_end = info->bytes + info->offset;
2099

2100
			info->bytes = offset - info->offset;
2101
			ret = link_free_space(ctl, info);
2102 2103 2104 2105
			WARN_ON(ret);
			if (ret)
				goto out_lock;

2106 2107 2108 2109 2110 2111 2112 2113 2114 2115 2116 2117 2118 2119 2120 2121
			/* Not enough bytes in this entry to satisfy us */
			if (old_end < offset + bytes) {
				bytes -= old_end - offset;
				offset = old_end;
				goto again;
			} else if (old_end == offset + bytes) {
				/* all done */
				goto out_lock;
			}
			spin_unlock(&ctl->tree_lock);

			ret = btrfs_add_free_space(block_group, offset + bytes,
						   old_end - (offset + bytes));
			WARN_ON(ret);
			goto out;
		}
J
Josef Bacik 已提交
2122
	}
2123

2124
	ret = remove_from_bitmap(ctl, info, &offset, &bytes);
2125 2126
	if (ret == -EAGAIN) {
		re_search = true;
2127
		goto again;
2128
	}
2129
out_lock:
2130
	spin_unlock(&ctl->tree_lock);
J
Josef Bacik 已提交
2131
out:
2132 2133 2134
	return ret;
}

J
Josef Bacik 已提交
2135 2136 2137
void btrfs_dump_free_space(struct btrfs_block_group_cache *block_group,
			   u64 bytes)
{
2138
	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
J
Josef Bacik 已提交
2139 2140 2141 2142
	struct btrfs_free_space *info;
	struct rb_node *n;
	int count = 0;

2143
	for (n = rb_first(&ctl->free_space_offset); n; n = rb_next(n)) {
J
Josef Bacik 已提交
2144
		info = rb_entry(n, struct btrfs_free_space, offset_index);
L
Liu Bo 已提交
2145
		if (info->bytes >= bytes && !block_group->ro)
J
Josef Bacik 已提交
2146
			count++;
2147 2148 2149
		btrfs_crit(block_group->fs_info,
			   "entry offset %llu, bytes %llu, bitmap %s",
			   info->offset, info->bytes,
2150
		       (info->bitmap) ? "yes" : "no");
J
Josef Bacik 已提交
2151
	}
2152
	btrfs_info(block_group->fs_info, "block group has cluster?: %s",
2153
	       list_empty(&block_group->cluster_list) ? "no" : "yes");
2154 2155
	btrfs_info(block_group->fs_info,
		   "%d blocks of free space at or bigger than bytes is", count);
J
Josef Bacik 已提交
2156 2157
}

2158
void btrfs_init_free_space_ctl(struct btrfs_block_group_cache *block_group)
J
Josef Bacik 已提交
2159
{
2160
	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
J
Josef Bacik 已提交
2161

2162 2163 2164 2165 2166
	spin_lock_init(&ctl->tree_lock);
	ctl->unit = block_group->sectorsize;
	ctl->start = block_group->key.objectid;
	ctl->private = block_group;
	ctl->op = &free_space_op;
J
Josef Bacik 已提交
2167

2168 2169 2170 2171 2172 2173 2174
	/*
	 * we only want to have 32k of ram per block group for keeping
	 * track of free space, and if we pass 1/2 of that we want to
	 * start converting things over to using bitmaps
	 */
	ctl->extents_thresh = ((1024 * 32) / 2) /
				sizeof(struct btrfs_free_space);
J
Josef Bacik 已提交
2175 2176
}

2177 2178 2179 2180 2181 2182 2183 2184 2185 2186 2187
/*
 * for a given cluster, put all of its extents back into the free
 * space cache.  If the block group passed doesn't match the block group
 * pointed to by the cluster, someone else raced in and freed the
 * cluster already.  In that case, we just return without changing anything
 */
static int
__btrfs_return_cluster_to_free_space(
			     struct btrfs_block_group_cache *block_group,
			     struct btrfs_free_cluster *cluster)
{
2188
	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2189 2190 2191 2192 2193 2194 2195
	struct btrfs_free_space *entry;
	struct rb_node *node;

	spin_lock(&cluster->lock);
	if (cluster->block_group != block_group)
		goto out;

2196
	cluster->block_group = NULL;
2197
	cluster->window_start = 0;
2198 2199
	list_del_init(&cluster->block_group_list);

2200
	node = rb_first(&cluster->root);
2201
	while (node) {
2202 2203
		bool bitmap;

2204 2205 2206
		entry = rb_entry(node, struct btrfs_free_space, offset_index);
		node = rb_next(&entry->offset_index);
		rb_erase(&entry->offset_index, &cluster->root);
2207 2208 2209

		bitmap = (entry->bitmap != NULL);
		if (!bitmap)
2210 2211
			try_merge_free_space(ctl, entry, false);
		tree_insert_offset(&ctl->free_space_offset,
2212
				   entry->offset, &entry->offset_index, bitmap);
2213
	}
2214
	cluster->root = RB_ROOT;
2215

2216 2217
out:
	spin_unlock(&cluster->lock);
2218
	btrfs_put_block_group(block_group);
2219 2220 2221
	return 0;
}

2222 2223
static void __btrfs_remove_free_space_cache_locked(
				struct btrfs_free_space_ctl *ctl)
J
Josef Bacik 已提交
2224 2225 2226
{
	struct btrfs_free_space *info;
	struct rb_node *node;
2227 2228 2229

	while ((node = rb_last(&ctl->free_space_offset)) != NULL) {
		info = rb_entry(node, struct btrfs_free_space, offset_index);
2230 2231 2232 2233 2234 2235
		if (!info->bitmap) {
			unlink_free_space(ctl, info);
			kmem_cache_free(btrfs_free_space_cachep, info);
		} else {
			free_bitmap(ctl, info);
		}
2236 2237 2238 2239 2240 2241
		if (need_resched()) {
			spin_unlock(&ctl->tree_lock);
			cond_resched();
			spin_lock(&ctl->tree_lock);
		}
	}
2242 2243 2244 2245 2246 2247
}

void __btrfs_remove_free_space_cache(struct btrfs_free_space_ctl *ctl)
{
	spin_lock(&ctl->tree_lock);
	__btrfs_remove_free_space_cache_locked(ctl);
2248 2249 2250 2251 2252 2253
	spin_unlock(&ctl->tree_lock);
}

void btrfs_remove_free_space_cache(struct btrfs_block_group_cache *block_group)
{
	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2254
	struct btrfs_free_cluster *cluster;
2255
	struct list_head *head;
J
Josef Bacik 已提交
2256

2257
	spin_lock(&ctl->tree_lock);
2258 2259 2260 2261
	while ((head = block_group->cluster_list.next) !=
	       &block_group->cluster_list) {
		cluster = list_entry(head, struct btrfs_free_cluster,
				     block_group_list);
2262 2263 2264

		WARN_ON(cluster->block_group != block_group);
		__btrfs_return_cluster_to_free_space(block_group, cluster);
2265
		if (need_resched()) {
2266
			spin_unlock(&ctl->tree_lock);
2267
			cond_resched();
2268
			spin_lock(&ctl->tree_lock);
2269
		}
2270
	}
2271
	__btrfs_remove_free_space_cache_locked(ctl);
2272
	spin_unlock(&ctl->tree_lock);
2273

J
Josef Bacik 已提交
2274 2275
}

2276
u64 btrfs_find_space_for_alloc(struct btrfs_block_group_cache *block_group,
2277 2278
			       u64 offset, u64 bytes, u64 empty_size,
			       u64 *max_extent_size)
J
Josef Bacik 已提交
2279
{
2280
	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2281
	struct btrfs_free_space *entry = NULL;
2282
	u64 bytes_search = bytes + empty_size;
2283
	u64 ret = 0;
D
David Woodhouse 已提交
2284 2285
	u64 align_gap = 0;
	u64 align_gap_len = 0;
J
Josef Bacik 已提交
2286

2287
	spin_lock(&ctl->tree_lock);
D
David Woodhouse 已提交
2288
	entry = find_free_space(ctl, &offset, &bytes_search,
2289
				block_group->full_stripe_len, max_extent_size);
2290
	if (!entry)
2291 2292 2293 2294
		goto out;

	ret = offset;
	if (entry->bitmap) {
2295
		bitmap_clear_bits(ctl, entry, offset, bytes);
2296
		if (!entry->bytes)
2297
			free_bitmap(ctl, entry);
2298
	} else {
2299
		unlink_free_space(ctl, entry);
D
David Woodhouse 已提交
2300 2301 2302 2303 2304 2305 2306
		align_gap_len = offset - entry->offset;
		align_gap = entry->offset;

		entry->offset = offset + bytes;
		WARN_ON(entry->bytes < bytes + align_gap_len);

		entry->bytes -= bytes + align_gap_len;
2307
		if (!entry->bytes)
2308
			kmem_cache_free(btrfs_free_space_cachep, entry);
2309
		else
2310
			link_free_space(ctl, entry);
2311
	}
2312
out:
2313
	spin_unlock(&ctl->tree_lock);
J
Josef Bacik 已提交
2314

D
David Woodhouse 已提交
2315 2316
	if (align_gap_len)
		__btrfs_add_free_space(ctl, align_gap, align_gap_len);
J
Josef Bacik 已提交
2317 2318
	return ret;
}
2319 2320 2321 2322 2323 2324 2325 2326 2327 2328 2329 2330 2331

/*
 * given a cluster, put all of its extents back into the free space
 * cache.  If a block group is passed, this function will only free
 * a cluster that belongs to the passed block group.
 *
 * Otherwise, it'll get a reference on the block group pointed to by the
 * cluster and remove the cluster from it.
 */
int btrfs_return_cluster_to_free_space(
			       struct btrfs_block_group_cache *block_group,
			       struct btrfs_free_cluster *cluster)
{
2332
	struct btrfs_free_space_ctl *ctl;
2333 2334 2335 2336 2337 2338 2339 2340 2341 2342 2343 2344 2345 2346 2347 2348 2349 2350
	int ret;

	/* first, get a safe pointer to the block group */
	spin_lock(&cluster->lock);
	if (!block_group) {
		block_group = cluster->block_group;
		if (!block_group) {
			spin_unlock(&cluster->lock);
			return 0;
		}
	} else if (cluster->block_group != block_group) {
		/* someone else has already freed it don't redo their work */
		spin_unlock(&cluster->lock);
		return 0;
	}
	atomic_inc(&block_group->count);
	spin_unlock(&cluster->lock);

2351 2352
	ctl = block_group->free_space_ctl;

2353
	/* now return any extents the cluster had on it */
2354
	spin_lock(&ctl->tree_lock);
2355
	ret = __btrfs_return_cluster_to_free_space(block_group, cluster);
2356
	spin_unlock(&ctl->tree_lock);
2357 2358 2359 2360 2361 2362

	/* finally drop our ref */
	btrfs_put_block_group(block_group);
	return ret;
}

2363 2364
static u64 btrfs_alloc_from_bitmap(struct btrfs_block_group_cache *block_group,
				   struct btrfs_free_cluster *cluster,
2365
				   struct btrfs_free_space *entry,
2366 2367
				   u64 bytes, u64 min_start,
				   u64 *max_extent_size)
2368
{
2369
	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2370 2371 2372 2373 2374 2375 2376 2377
	int err;
	u64 search_start = cluster->window_start;
	u64 search_bytes = bytes;
	u64 ret = 0;

	search_start = min_start;
	search_bytes = bytes;

2378
	err = search_bitmap(ctl, entry, &search_start, &search_bytes);
2379 2380 2381
	if (err) {
		if (search_bytes > *max_extent_size)
			*max_extent_size = search_bytes;
2382
		return 0;
2383
	}
2384 2385

	ret = search_start;
2386
	__bitmap_clear_bits(ctl, entry, ret, bytes);
2387 2388 2389 2390

	return ret;
}

2391 2392 2393 2394 2395 2396 2397
/*
 * given a cluster, try to allocate 'bytes' from it, returns 0
 * if it couldn't find anything suitably large, or a logical disk offset
 * if things worked out
 */
u64 btrfs_alloc_from_cluster(struct btrfs_block_group_cache *block_group,
			     struct btrfs_free_cluster *cluster, u64 bytes,
2398
			     u64 min_start, u64 *max_extent_size)
2399
{
2400
	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2401 2402 2403 2404 2405 2406 2407 2408 2409 2410 2411 2412 2413 2414 2415 2416
	struct btrfs_free_space *entry = NULL;
	struct rb_node *node;
	u64 ret = 0;

	spin_lock(&cluster->lock);
	if (bytes > cluster->max_size)
		goto out;

	if (cluster->block_group != block_group)
		goto out;

	node = rb_first(&cluster->root);
	if (!node)
		goto out;

	entry = rb_entry(node, struct btrfs_free_space, offset_index);
2417
	while (1) {
2418 2419 2420
		if (entry->bytes < bytes && entry->bytes > *max_extent_size)
			*max_extent_size = entry->bytes;

2421 2422
		if (entry->bytes < bytes ||
		    (!entry->bitmap && entry->offset < min_start)) {
2423 2424 2425 2426 2427 2428 2429 2430
			node = rb_next(&entry->offset_index);
			if (!node)
				break;
			entry = rb_entry(node, struct btrfs_free_space,
					 offset_index);
			continue;
		}

2431 2432 2433
		if (entry->bitmap) {
			ret = btrfs_alloc_from_bitmap(block_group,
						      cluster, entry, bytes,
2434 2435
						      cluster->window_start,
						      max_extent_size);
2436 2437 2438 2439 2440 2441 2442 2443
			if (ret == 0) {
				node = rb_next(&entry->offset_index);
				if (!node)
					break;
				entry = rb_entry(node, struct btrfs_free_space,
						 offset_index);
				continue;
			}
2444
			cluster->window_start += bytes;
2445 2446 2447 2448 2449 2450
		} else {
			ret = entry->offset;

			entry->offset += bytes;
			entry->bytes -= bytes;
		}
2451

2452
		if (entry->bytes == 0)
2453 2454 2455 2456 2457
			rb_erase(&entry->offset_index, &cluster->root);
		break;
	}
out:
	spin_unlock(&cluster->lock);
2458

2459 2460 2461
	if (!ret)
		return 0;

2462
	spin_lock(&ctl->tree_lock);
2463

2464
	ctl->free_space -= bytes;
2465
	if (entry->bytes == 0) {
2466
		ctl->free_extents--;
2467 2468
		if (entry->bitmap) {
			kfree(entry->bitmap);
2469 2470
			ctl->total_bitmaps--;
			ctl->op->recalc_thresholds(ctl);
2471
		}
2472
		kmem_cache_free(btrfs_free_space_cachep, entry);
2473 2474
	}

2475
	spin_unlock(&ctl->tree_lock);
2476

2477 2478 2479
	return ret;
}

2480 2481 2482
static int btrfs_bitmap_cluster(struct btrfs_block_group_cache *block_group,
				struct btrfs_free_space *entry,
				struct btrfs_free_cluster *cluster,
2483 2484
				u64 offset, u64 bytes,
				u64 cont1_bytes, u64 min_bytes)
2485
{
2486
	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2487 2488
	unsigned long next_zero;
	unsigned long i;
2489 2490
	unsigned long want_bits;
	unsigned long min_bits;
2491 2492 2493
	unsigned long found_bits;
	unsigned long start = 0;
	unsigned long total_found = 0;
2494
	int ret;
2495

2496
	i = offset_to_bit(entry->offset, ctl->unit,
2497
			  max_t(u64, offset, entry->offset));
2498 2499
	want_bits = bytes_to_bits(bytes, ctl->unit);
	min_bits = bytes_to_bits(min_bytes, ctl->unit);
2500 2501 2502

again:
	found_bits = 0;
2503
	for_each_set_bit_from(i, entry->bitmap, BITS_PER_BITMAP) {
2504 2505
		next_zero = find_next_zero_bit(entry->bitmap,
					       BITS_PER_BITMAP, i);
2506
		if (next_zero - i >= min_bits) {
2507 2508 2509 2510 2511 2512 2513
			found_bits = next_zero - i;
			break;
		}
		i = next_zero;
	}

	if (!found_bits)
2514
		return -ENOSPC;
2515

2516
	if (!total_found) {
2517
		start = i;
2518
		cluster->max_size = 0;
2519 2520 2521 2522
	}

	total_found += found_bits;

2523 2524
	if (cluster->max_size < found_bits * ctl->unit)
		cluster->max_size = found_bits * ctl->unit;
2525

2526 2527
	if (total_found < want_bits || cluster->max_size < cont1_bytes) {
		i = next_zero + 1;
2528 2529 2530
		goto again;
	}

2531
	cluster->window_start = start * ctl->unit + entry->offset;
2532
	rb_erase(&entry->offset_index, &ctl->free_space_offset);
2533 2534
	ret = tree_insert_offset(&cluster->root, entry->offset,
				 &entry->offset_index, 1);
2535
	ASSERT(!ret); /* -EEXIST; Logic error */
2536

J
Josef Bacik 已提交
2537
	trace_btrfs_setup_cluster(block_group, cluster,
2538
				  total_found * ctl->unit, 1);
2539 2540 2541
	return 0;
}

2542 2543
/*
 * This searches the block group for just extents to fill the cluster with.
2544 2545
 * Try to find a cluster with at least bytes total bytes, at least one
 * extent of cont1_bytes, and other clusters of at least min_bytes.
2546
 */
2547 2548 2549 2550
static noinline int
setup_cluster_no_bitmap(struct btrfs_block_group_cache *block_group,
			struct btrfs_free_cluster *cluster,
			struct list_head *bitmaps, u64 offset, u64 bytes,
2551
			u64 cont1_bytes, u64 min_bytes)
2552
{
2553
	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2554 2555 2556 2557 2558 2559
	struct btrfs_free_space *first = NULL;
	struct btrfs_free_space *entry = NULL;
	struct btrfs_free_space *last;
	struct rb_node *node;
	u64 window_free;
	u64 max_extent;
J
Josef Bacik 已提交
2560
	u64 total_size = 0;
2561

2562
	entry = tree_search_offset(ctl, offset, 0, 1);
2563 2564 2565 2566 2567 2568 2569
	if (!entry)
		return -ENOSPC;

	/*
	 * We don't want bitmaps, so just move along until we find a normal
	 * extent entry.
	 */
2570 2571
	while (entry->bitmap || entry->bytes < min_bytes) {
		if (entry->bitmap && list_empty(&entry->list))
2572
			list_add_tail(&entry->list, bitmaps);
2573 2574 2575 2576 2577 2578 2579 2580 2581 2582 2583
		node = rb_next(&entry->offset_index);
		if (!node)
			return -ENOSPC;
		entry = rb_entry(node, struct btrfs_free_space, offset_index);
	}

	window_free = entry->bytes;
	max_extent = entry->bytes;
	first = entry;
	last = entry;

2584 2585
	for (node = rb_next(&entry->offset_index); node;
	     node = rb_next(&entry->offset_index)) {
2586 2587
		entry = rb_entry(node, struct btrfs_free_space, offset_index);

2588 2589 2590
		if (entry->bitmap) {
			if (list_empty(&entry->list))
				list_add_tail(&entry->list, bitmaps);
2591
			continue;
2592 2593
		}

2594 2595 2596 2597 2598 2599
		if (entry->bytes < min_bytes)
			continue;

		last = entry;
		window_free += entry->bytes;
		if (entry->bytes > max_extent)
2600 2601 2602
			max_extent = entry->bytes;
	}

2603 2604 2605
	if (window_free < bytes || max_extent < cont1_bytes)
		return -ENOSPC;

2606 2607 2608 2609 2610 2611 2612 2613 2614 2615 2616 2617 2618
	cluster->window_start = first->offset;

	node = &first->offset_index;

	/*
	 * now we've found our entries, pull them out of the free space
	 * cache and put them into the cluster rbtree
	 */
	do {
		int ret;

		entry = rb_entry(node, struct btrfs_free_space, offset_index);
		node = rb_next(&entry->offset_index);
2619
		if (entry->bitmap || entry->bytes < min_bytes)
2620 2621
			continue;

2622
		rb_erase(&entry->offset_index, &ctl->free_space_offset);
2623 2624
		ret = tree_insert_offset(&cluster->root, entry->offset,
					 &entry->offset_index, 0);
J
Josef Bacik 已提交
2625
		total_size += entry->bytes;
2626
		ASSERT(!ret); /* -EEXIST; Logic error */
2627 2628 2629
	} while (node && entry != last);

	cluster->max_size = max_extent;
J
Josef Bacik 已提交
2630
	trace_btrfs_setup_cluster(block_group, cluster, total_size, 0);
2631 2632 2633 2634 2635 2636 2637
	return 0;
}

/*
 * This specifically looks for bitmaps that may work in the cluster, we assume
 * that we have already failed to find extents that will work.
 */
2638 2639 2640 2641
static noinline int
setup_cluster_bitmap(struct btrfs_block_group_cache *block_group,
		     struct btrfs_free_cluster *cluster,
		     struct list_head *bitmaps, u64 offset, u64 bytes,
2642
		     u64 cont1_bytes, u64 min_bytes)
2643
{
2644
	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2645 2646
	struct btrfs_free_space *entry;
	int ret = -ENOSPC;
2647
	u64 bitmap_offset = offset_to_bitmap(ctl, offset);
2648

2649
	if (ctl->total_bitmaps == 0)
2650 2651
		return -ENOSPC;

2652 2653 2654 2655 2656 2657 2658 2659 2660 2661 2662
	/*
	 * The bitmap that covers offset won't be in the list unless offset
	 * is just its start offset.
	 */
	entry = list_first_entry(bitmaps, struct btrfs_free_space, list);
	if (entry->offset != bitmap_offset) {
		entry = tree_search_offset(ctl, bitmap_offset, 1, 0);
		if (entry && list_empty(&entry->list))
			list_add(&entry->list, bitmaps);
	}

2663
	list_for_each_entry(entry, bitmaps, list) {
2664
		if (entry->bytes < bytes)
2665 2666
			continue;
		ret = btrfs_bitmap_cluster(block_group, entry, cluster, offset,
2667
					   bytes, cont1_bytes, min_bytes);
2668 2669 2670 2671 2672
		if (!ret)
			return 0;
	}

	/*
2673 2674
	 * The bitmaps list has all the bitmaps that record free space
	 * starting after offset, so no more search is required.
2675
	 */
2676
	return -ENOSPC;
2677 2678
}

2679 2680
/*
 * here we try to find a cluster of blocks in a block group.  The goal
2681
 * is to find at least bytes+empty_size.
2682 2683 2684 2685 2686
 * We might not find them all in one contiguous area.
 *
 * returns zero and sets up cluster if things worked out, otherwise
 * it returns -enospc
 */
2687
int btrfs_find_space_cluster(struct btrfs_root *root,
2688 2689 2690 2691
			     struct btrfs_block_group_cache *block_group,
			     struct btrfs_free_cluster *cluster,
			     u64 offset, u64 bytes, u64 empty_size)
{
2692
	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2693
	struct btrfs_free_space *entry, *tmp;
2694
	LIST_HEAD(bitmaps);
2695
	u64 min_bytes;
2696
	u64 cont1_bytes;
2697 2698
	int ret;

2699 2700 2701 2702 2703 2704
	/*
	 * Choose the minimum extent size we'll require for this
	 * cluster.  For SSD_SPREAD, don't allow any fragmentation.
	 * For metadata, allow allocates with smaller extents.  For
	 * data, keep it dense.
	 */
2705
	if (btrfs_test_opt(root, SSD_SPREAD)) {
2706
		cont1_bytes = min_bytes = bytes + empty_size;
2707
	} else if (block_group->flags & BTRFS_BLOCK_GROUP_METADATA) {
2708 2709 2710 2711 2712 2713
		cont1_bytes = bytes;
		min_bytes = block_group->sectorsize;
	} else {
		cont1_bytes = max(bytes, (bytes + empty_size) >> 2);
		min_bytes = block_group->sectorsize;
	}
2714

2715
	spin_lock(&ctl->tree_lock);
2716 2717 2718 2719 2720

	/*
	 * If we know we don't have enough space to make a cluster don't even
	 * bother doing all the work to try and find one.
	 */
2721
	if (ctl->free_space < bytes) {
2722
		spin_unlock(&ctl->tree_lock);
2723 2724 2725
		return -ENOSPC;
	}

2726 2727 2728 2729 2730 2731 2732 2733
	spin_lock(&cluster->lock);

	/* someone already found a cluster, hooray */
	if (cluster->block_group) {
		ret = 0;
		goto out;
	}

J
Josef Bacik 已提交
2734 2735 2736 2737
	trace_btrfs_find_cluster(block_group, offset, bytes, empty_size,
				 min_bytes);

	INIT_LIST_HEAD(&bitmaps);
2738
	ret = setup_cluster_no_bitmap(block_group, cluster, &bitmaps, offset,
2739 2740
				      bytes + empty_size,
				      cont1_bytes, min_bytes);
2741
	if (ret)
2742
		ret = setup_cluster_bitmap(block_group, cluster, &bitmaps,
2743 2744
					   offset, bytes + empty_size,
					   cont1_bytes, min_bytes);
2745 2746 2747 2748

	/* Clear our temporary list */
	list_for_each_entry_safe(entry, tmp, &bitmaps, list)
		list_del_init(&entry->list);
2749

2750 2751 2752 2753 2754
	if (!ret) {
		atomic_inc(&block_group->count);
		list_add_tail(&cluster->block_group_list,
			      &block_group->cluster_list);
		cluster->block_group = block_group;
J
Josef Bacik 已提交
2755 2756
	} else {
		trace_btrfs_failed_cluster_setup(block_group);
2757 2758 2759
	}
out:
	spin_unlock(&cluster->lock);
2760
	spin_unlock(&ctl->tree_lock);
2761 2762 2763 2764 2765 2766 2767 2768 2769 2770 2771

	return ret;
}

/*
 * simple code to zero out a cluster
 */
void btrfs_init_free_cluster(struct btrfs_free_cluster *cluster)
{
	spin_lock_init(&cluster->lock);
	spin_lock_init(&cluster->refill_lock);
2772
	cluster->root = RB_ROOT;
2773 2774 2775 2776 2777
	cluster->max_size = 0;
	INIT_LIST_HEAD(&cluster->block_group_list);
	cluster->block_group = NULL;
}

2778 2779 2780
static int do_trimming(struct btrfs_block_group_cache *block_group,
		       u64 *total_trimmed, u64 start, u64 bytes,
		       u64 reserved_start, u64 reserved_bytes)
2781
{
2782
	struct btrfs_space_info *space_info = block_group->space_info;
2783
	struct btrfs_fs_info *fs_info = block_group->fs_info;
2784 2785 2786
	int ret;
	int update = 0;
	u64 trimmed = 0;
2787

2788 2789 2790 2791 2792 2793 2794 2795 2796 2797 2798 2799 2800 2801 2802 2803 2804 2805 2806 2807 2808 2809 2810 2811 2812 2813 2814 2815 2816 2817 2818 2819 2820 2821 2822 2823 2824 2825 2826 2827 2828
	spin_lock(&space_info->lock);
	spin_lock(&block_group->lock);
	if (!block_group->ro) {
		block_group->reserved += reserved_bytes;
		space_info->bytes_reserved += reserved_bytes;
		update = 1;
	}
	spin_unlock(&block_group->lock);
	spin_unlock(&space_info->lock);

	ret = btrfs_error_discard_extent(fs_info->extent_root,
					 start, bytes, &trimmed);
	if (!ret)
		*total_trimmed += trimmed;

	btrfs_add_free_space(block_group, reserved_start, reserved_bytes);

	if (update) {
		spin_lock(&space_info->lock);
		spin_lock(&block_group->lock);
		if (block_group->ro)
			space_info->bytes_readonly += reserved_bytes;
		block_group->reserved -= reserved_bytes;
		space_info->bytes_reserved -= reserved_bytes;
		spin_unlock(&space_info->lock);
		spin_unlock(&block_group->lock);
	}

	return ret;
}

static int trim_no_bitmap(struct btrfs_block_group_cache *block_group,
			  u64 *total_trimmed, u64 start, u64 end, u64 minlen)
{
	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
	struct btrfs_free_space *entry;
	struct rb_node *node;
	int ret = 0;
	u64 extent_start;
	u64 extent_bytes;
	u64 bytes;
2829 2830

	while (start < end) {
2831
		spin_lock(&ctl->tree_lock);
2832

2833 2834
		if (ctl->free_space < minlen) {
			spin_unlock(&ctl->tree_lock);
2835 2836 2837
			break;
		}

2838
		entry = tree_search_offset(ctl, start, 0, 1);
2839
		if (!entry) {
2840
			spin_unlock(&ctl->tree_lock);
2841 2842 2843
			break;
		}

2844 2845 2846 2847
		/* skip bitmaps */
		while (entry->bitmap) {
			node = rb_next(&entry->offset_index);
			if (!node) {
2848
				spin_unlock(&ctl->tree_lock);
2849
				goto out;
2850
			}
2851 2852
			entry = rb_entry(node, struct btrfs_free_space,
					 offset_index);
2853 2854
		}

2855 2856 2857
		if (entry->offset >= end) {
			spin_unlock(&ctl->tree_lock);
			break;
2858 2859
		}

2860 2861 2862 2863 2864 2865 2866
		extent_start = entry->offset;
		extent_bytes = entry->bytes;
		start = max(start, extent_start);
		bytes = min(extent_start + extent_bytes, end) - start;
		if (bytes < minlen) {
			spin_unlock(&ctl->tree_lock);
			goto next;
2867 2868
		}

2869 2870 2871
		unlink_free_space(ctl, entry);
		kmem_cache_free(btrfs_free_space_cachep, entry);

2872
		spin_unlock(&ctl->tree_lock);
2873

2874 2875 2876 2877 2878 2879
		ret = do_trimming(block_group, total_trimmed, start, bytes,
				  extent_start, extent_bytes);
		if (ret)
			break;
next:
		start += bytes;
2880

2881 2882 2883 2884 2885 2886 2887 2888 2889 2890 2891 2892 2893 2894 2895 2896 2897 2898 2899 2900 2901 2902 2903 2904 2905 2906 2907 2908 2909 2910 2911 2912 2913 2914 2915 2916 2917 2918 2919 2920 2921 2922 2923 2924 2925 2926 2927 2928 2929 2930 2931 2932 2933 2934 2935 2936 2937 2938 2939 2940 2941 2942 2943 2944 2945 2946 2947 2948 2949
		if (fatal_signal_pending(current)) {
			ret = -ERESTARTSYS;
			break;
		}

		cond_resched();
	}
out:
	return ret;
}

static int trim_bitmaps(struct btrfs_block_group_cache *block_group,
			u64 *total_trimmed, u64 start, u64 end, u64 minlen)
{
	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
	struct btrfs_free_space *entry;
	int ret = 0;
	int ret2;
	u64 bytes;
	u64 offset = offset_to_bitmap(ctl, start);

	while (offset < end) {
		bool next_bitmap = false;

		spin_lock(&ctl->tree_lock);

		if (ctl->free_space < minlen) {
			spin_unlock(&ctl->tree_lock);
			break;
		}

		entry = tree_search_offset(ctl, offset, 1, 0);
		if (!entry) {
			spin_unlock(&ctl->tree_lock);
			next_bitmap = true;
			goto next;
		}

		bytes = minlen;
		ret2 = search_bitmap(ctl, entry, &start, &bytes);
		if (ret2 || start >= end) {
			spin_unlock(&ctl->tree_lock);
			next_bitmap = true;
			goto next;
		}

		bytes = min(bytes, end - start);
		if (bytes < minlen) {
			spin_unlock(&ctl->tree_lock);
			goto next;
		}

		bitmap_clear_bits(ctl, entry, start, bytes);
		if (entry->bytes == 0)
			free_bitmap(ctl, entry);

		spin_unlock(&ctl->tree_lock);

		ret = do_trimming(block_group, total_trimmed, start, bytes,
				  start, bytes);
		if (ret)
			break;
next:
		if (next_bitmap) {
			offset += BITS_PER_BITMAP * ctl->unit;
		} else {
			start += bytes;
			if (start >= offset + BITS_PER_BITMAP * ctl->unit)
				offset += BITS_PER_BITMAP * ctl->unit;
2950 2951 2952 2953 2954 2955 2956 2957 2958 2959 2960 2961
		}

		if (fatal_signal_pending(current)) {
			ret = -ERESTARTSYS;
			break;
		}

		cond_resched();
	}

	return ret;
}
2962

2963 2964 2965 2966 2967 2968 2969 2970 2971 2972 2973 2974 2975 2976 2977 2978
int btrfs_trim_block_group(struct btrfs_block_group_cache *block_group,
			   u64 *trimmed, u64 start, u64 end, u64 minlen)
{
	int ret;

	*trimmed = 0;

	ret = trim_no_bitmap(block_group, trimmed, start, end, minlen);
	if (ret)
		return ret;

	ret = trim_bitmaps(block_group, trimmed, start, end, minlen);

	return ret;
}

2979 2980 2981 2982 2983 2984 2985 2986 2987 2988 2989 2990 2991 2992 2993 2994 2995 2996 2997 2998 2999 3000 3001 3002 3003 3004 3005 3006 3007 3008 3009 3010 3011 3012 3013 3014 3015
/*
 * Find the left-most item in the cache tree, and then return the
 * smallest inode number in the item.
 *
 * Note: the returned inode number may not be the smallest one in
 * the tree, if the left-most item is a bitmap.
 */
u64 btrfs_find_ino_for_alloc(struct btrfs_root *fs_root)
{
	struct btrfs_free_space_ctl *ctl = fs_root->free_ino_ctl;
	struct btrfs_free_space *entry = NULL;
	u64 ino = 0;

	spin_lock(&ctl->tree_lock);

	if (RB_EMPTY_ROOT(&ctl->free_space_offset))
		goto out;

	entry = rb_entry(rb_first(&ctl->free_space_offset),
			 struct btrfs_free_space, offset_index);

	if (!entry->bitmap) {
		ino = entry->offset;

		unlink_free_space(ctl, entry);
		entry->offset++;
		entry->bytes--;
		if (!entry->bytes)
			kmem_cache_free(btrfs_free_space_cachep, entry);
		else
			link_free_space(ctl, entry);
	} else {
		u64 offset = 0;
		u64 count = 1;
		int ret;

		ret = search_bitmap(ctl, entry, &offset, &count);
3016
		/* Logic error; Should be empty if it can't find anything */
3017
		ASSERT(!ret);
3018 3019 3020 3021 3022 3023 3024 3025 3026 3027 3028

		ino = offset;
		bitmap_clear_bits(ctl, entry, offset, 1);
		if (entry->bytes == 0)
			free_bitmap(ctl, entry);
	}
out:
	spin_unlock(&ctl->tree_lock);

	return ino;
}
3029 3030 3031 3032 3033 3034

struct inode *lookup_free_ino_inode(struct btrfs_root *root,
				    struct btrfs_path *path)
{
	struct inode *inode = NULL;

3035 3036 3037 3038
	spin_lock(&root->ino_cache_lock);
	if (root->ino_cache_inode)
		inode = igrab(root->ino_cache_inode);
	spin_unlock(&root->ino_cache_lock);
3039 3040 3041 3042 3043 3044 3045
	if (inode)
		return inode;

	inode = __lookup_free_space_inode(root, path, 0);
	if (IS_ERR(inode))
		return inode;

3046
	spin_lock(&root->ino_cache_lock);
3047
	if (!btrfs_fs_closing(root->fs_info))
3048 3049
		root->ino_cache_inode = igrab(inode);
	spin_unlock(&root->ino_cache_lock);
3050 3051 3052 3053 3054 3055 3056 3057 3058 3059 3060 3061 3062 3063 3064 3065 3066 3067 3068 3069

	return inode;
}

int create_free_ino_inode(struct btrfs_root *root,
			  struct btrfs_trans_handle *trans,
			  struct btrfs_path *path)
{
	return __create_free_space_inode(root, trans, path,
					 BTRFS_FREE_INO_OBJECTID, 0);
}

int load_free_ino_cache(struct btrfs_fs_info *fs_info, struct btrfs_root *root)
{
	struct btrfs_free_space_ctl *ctl = root->free_ino_ctl;
	struct btrfs_path *path;
	struct inode *inode;
	int ret = 0;
	u64 root_gen = btrfs_root_generation(&root->root_item);

C
Chris Mason 已提交
3070 3071 3072
	if (!btrfs_test_opt(root, INODE_MAP_CACHE))
		return 0;

3073 3074 3075 3076
	/*
	 * If we're unmounting then just return, since this does a search on the
	 * normal root and not the commit root and we could deadlock.
	 */
3077
	if (btrfs_fs_closing(fs_info))
3078 3079 3080 3081 3082 3083 3084 3085 3086 3087 3088 3089 3090 3091 3092 3093
		return 0;

	path = btrfs_alloc_path();
	if (!path)
		return 0;

	inode = lookup_free_ino_inode(root, path);
	if (IS_ERR(inode))
		goto out;

	if (root_gen != BTRFS_I(inode)->generation)
		goto out_put;

	ret = __load_free_space_cache(root, inode, ctl, path, 0);

	if (ret < 0)
3094 3095 3096
		btrfs_err(fs_info,
			"failed to load free ino cache for root %llu",
			root->root_key.objectid);
3097 3098 3099 3100 3101 3102 3103 3104 3105
out_put:
	iput(inode);
out:
	btrfs_free_path(path);
	return ret;
}

int btrfs_write_out_ino_cache(struct btrfs_root *root,
			      struct btrfs_trans_handle *trans,
3106 3107
			      struct btrfs_path *path,
			      struct inode *inode)
3108 3109 3110 3111
{
	struct btrfs_free_space_ctl *ctl = root->free_ino_ctl;
	int ret;

C
Chris Mason 已提交
3112 3113 3114
	if (!btrfs_test_opt(root, INODE_MAP_CACHE))
		return 0;

3115
	ret = __btrfs_write_out_cache(root, inode, ctl, NULL, trans, path, 0);
3116 3117 3118
	if (ret) {
		btrfs_delalloc_release_metadata(inode, inode->i_size);
#ifdef DEBUG
3119 3120 3121
		btrfs_err(root->fs_info,
			"failed to write free ino cache for root %llu",
			root->root_key.objectid);
3122 3123
#endif
	}
3124 3125 3126

	return ret;
}
3127 3128

#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
3129 3130 3131 3132 3133 3134 3135 3136
/*
 * Use this if you need to make a bitmap or extent entry specifically, it
 * doesn't do any of the merging that add_free_space does, this acts a lot like
 * how the free space cache loading stuff works, so you can get really weird
 * configurations.
 */
int test_add_free_space_entry(struct btrfs_block_group_cache *cache,
			      u64 offset, u64 bytes, bool bitmap)
3137
{
3138 3139 3140 3141 3142
	struct btrfs_free_space_ctl *ctl = cache->free_space_ctl;
	struct btrfs_free_space *info = NULL, *bitmap_info;
	void *map = NULL;
	u64 bytes_added;
	int ret;
3143

3144 3145 3146 3147 3148
again:
	if (!info) {
		info = kmem_cache_zalloc(btrfs_free_space_cachep, GFP_NOFS);
		if (!info)
			return -ENOMEM;
3149 3150
	}

3151 3152 3153 3154 3155 3156 3157 3158 3159 3160 3161 3162 3163 3164 3165 3166 3167 3168 3169 3170 3171 3172 3173 3174 3175 3176 3177 3178
	if (!bitmap) {
		spin_lock(&ctl->tree_lock);
		info->offset = offset;
		info->bytes = bytes;
		ret = link_free_space(ctl, info);
		spin_unlock(&ctl->tree_lock);
		if (ret)
			kmem_cache_free(btrfs_free_space_cachep, info);
		return ret;
	}

	if (!map) {
		map = kzalloc(PAGE_CACHE_SIZE, GFP_NOFS);
		if (!map) {
			kmem_cache_free(btrfs_free_space_cachep, info);
			return -ENOMEM;
		}
	}

	spin_lock(&ctl->tree_lock);
	bitmap_info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
					 1, 0);
	if (!bitmap_info) {
		info->bitmap = map;
		map = NULL;
		add_new_bitmap(ctl, info, offset);
		bitmap_info = info;
	}
3179

3180 3181 3182 3183
	bytes_added = add_bytes_to_bitmap(ctl, bitmap_info, offset, bytes);
	bytes -= bytes_added;
	offset += bytes_added;
	spin_unlock(&ctl->tree_lock);
3184

3185 3186
	if (bytes)
		goto again;
3187

3188 3189 3190
	if (map)
		kfree(map);
	return 0;
3191 3192 3193 3194 3195 3196 3197
}

/*
 * Checks to see if the given range is in the free space cache.  This is really
 * just used to check the absence of space, so if there is free space in the
 * range at all we will return 1.
 */
3198 3199
int test_check_exists(struct btrfs_block_group_cache *cache,
		      u64 offset, u64 bytes)
3200 3201 3202 3203 3204 3205 3206 3207 3208 3209 3210 3211 3212 3213 3214 3215 3216 3217 3218 3219 3220 3221 3222 3223 3224 3225 3226 3227 3228 3229 3230 3231 3232 3233 3234 3235 3236 3237 3238 3239 3240 3241 3242 3243 3244 3245 3246 3247 3248 3249 3250 3251 3252 3253 3254 3255 3256 3257 3258 3259 3260 3261 3262 3263 3264 3265 3266 3267 3268 3269 3270 3271 3272 3273 3274 3275
{
	struct btrfs_free_space_ctl *ctl = cache->free_space_ctl;
	struct btrfs_free_space *info;
	int ret = 0;

	spin_lock(&ctl->tree_lock);
	info = tree_search_offset(ctl, offset, 0, 0);
	if (!info) {
		info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
					  1, 0);
		if (!info)
			goto out;
	}

have_info:
	if (info->bitmap) {
		u64 bit_off, bit_bytes;
		struct rb_node *n;
		struct btrfs_free_space *tmp;

		bit_off = offset;
		bit_bytes = ctl->unit;
		ret = search_bitmap(ctl, info, &bit_off, &bit_bytes);
		if (!ret) {
			if (bit_off == offset) {
				ret = 1;
				goto out;
			} else if (bit_off > offset &&
				   offset + bytes > bit_off) {
				ret = 1;
				goto out;
			}
		}

		n = rb_prev(&info->offset_index);
		while (n) {
			tmp = rb_entry(n, struct btrfs_free_space,
				       offset_index);
			if (tmp->offset + tmp->bytes < offset)
				break;
			if (offset + bytes < tmp->offset) {
				n = rb_prev(&info->offset_index);
				continue;
			}
			info = tmp;
			goto have_info;
		}

		n = rb_next(&info->offset_index);
		while (n) {
			tmp = rb_entry(n, struct btrfs_free_space,
				       offset_index);
			if (offset + bytes < tmp->offset)
				break;
			if (tmp->offset + tmp->bytes < offset) {
				n = rb_next(&info->offset_index);
				continue;
			}
			info = tmp;
			goto have_info;
		}

		goto out;
	}

	if (info->offset == offset) {
		ret = 1;
		goto out;
	}

	if (offset > info->offset && offset < info->offset + info->bytes)
		ret = 1;
out:
	spin_unlock(&ctl->tree_lock);
	return ret;
}
3276
#endif /* CONFIG_BTRFS_FS_RUN_SANITY_TESTS */