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linux-stable/fs/btrfs/free-space-cache.c
Qu Wenruo 55151ea9ec btrfs: migrate subpage code to folio interfaces 
Although subpage itself is conflicting with higher folio, since subpage
(sectorsize < PAGE_SIZE and nodesize < PAGE_SIZE) means we will never
need higher order folio, there is a hidden pitfall:

- btrfs_page_*() helpers

Those helpers are an abstraction to handle both subpage and non-subpage
cases, which means we're going to pass pages pointers to those helpers.

And since those helpers are shared between data and metadata paths, it's
unavoidable to let them to handle folios, including higher order
folios).

Meanwhile for true subpage case, we should only have a single page
backed folios anyway, thus add a new ASSERT() for btrfs_subpage_assert()
to ensure that.

Also since those helpers are shared between both data and metadata, add
some extra ASSERT()s for data path to make sure we only get single page
backed folio for now.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-12-15 23:03:58 +01:00

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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2008 Red Hat. All rights reserved.
*/
#include <linux/pagemap.h>
#include <linux/sched.h>
#include <linux/sched/signal.h>
#include <linux/slab.h>
#include <linux/math64.h>
#include <linux/ratelimit.h>
#include <linux/error-injection.h>
#include <linux/sched/mm.h>
#include "ctree.h"
#include "fs.h"
#include "messages.h"
#include "misc.h"
#include "free-space-cache.h"
#include "transaction.h"
#include "disk-io.h"
#include "extent_io.h"
#include "volumes.h"
#include "space-info.h"
#include "delalloc-space.h"
#include "block-group.h"
#include "discard.h"
#include "subpage.h"
#include "inode-item.h"
#include "accessors.h"
#include "file-item.h"
#include "file.h"
#include "super.h"
#define BITS_PER_BITMAP (PAGE_SIZE * 8UL)
#define MAX_CACHE_BYTES_PER_GIG SZ_64K
#define FORCE_EXTENT_THRESHOLD SZ_1M
static struct kmem_cache *btrfs_free_space_cachep;
static struct kmem_cache *btrfs_free_space_bitmap_cachep;
struct btrfs_trim_range {
u64 start;
u64 bytes;
struct list_head list;
};
static int link_free_space(struct btrfs_free_space_ctl *ctl,
struct btrfs_free_space *info);
static void unlink_free_space(struct btrfs_free_space_ctl *ctl,
struct btrfs_free_space *info, bool update_stat);
static int search_bitmap(struct btrfs_free_space_ctl *ctl,
struct btrfs_free_space *bitmap_info, u64 *offset,
u64 *bytes, bool for_alloc);
static void free_bitmap(struct btrfs_free_space_ctl *ctl,
struct btrfs_free_space *bitmap_info);
static void bitmap_clear_bits(struct btrfs_free_space_ctl *ctl,
struct btrfs_free_space *info, u64 offset,
u64 bytes, bool update_stats);
static void btrfs_crc32c_final(u32 crc, u8 *result)
{
put_unaligned_le32(~crc, result);
}
static void __btrfs_remove_free_space_cache(struct btrfs_free_space_ctl *ctl)
{
struct btrfs_free_space *info;
struct rb_node *node;
while ((node = rb_last(&ctl->free_space_offset)) != NULL) {
info = rb_entry(node, struct btrfs_free_space, offset_index);
if (!info->bitmap) {
unlink_free_space(ctl, info, true);
kmem_cache_free(btrfs_free_space_cachep, info);
} else {
free_bitmap(ctl, info);
}
cond_resched_lock(&ctl->tree_lock);
}
}
static struct inode *__lookup_free_space_inode(struct btrfs_root *root,
struct btrfs_path *path,
u64 offset)
{
struct btrfs_fs_info *fs_info = root->fs_info;
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;
unsigned nofs_flag;
int ret;
key.objectid = BTRFS_FREE_SPACE_OBJECTID;
key.offset = offset;
key.type = 0;
ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
if (ret < 0)
return ERR_PTR(ret);
if (ret > 0) {
btrfs_release_path(path);
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);
btrfs_release_path(path);
/*
* We are often under a trans handle at this point, so we need to make
* sure NOFS is set to keep us from deadlocking.
*/
nofs_flag = memalloc_nofs_save();
inode = btrfs_iget_path(fs_info->sb, location.objectid, root, path);
btrfs_release_path(path);
memalloc_nofs_restore(nofs_flag);
if (IS_ERR(inode))
return inode;
mapping_set_gfp_mask(inode->i_mapping,
mapping_gfp_constraint(inode->i_mapping,
~(__GFP_FS | __GFP_HIGHMEM)));
return inode;
}
struct inode *lookup_free_space_inode(struct btrfs_block_group *block_group,
struct btrfs_path *path)
{
struct btrfs_fs_info *fs_info = block_group->fs_info;
struct inode *inode = NULL;
u32 flags = BTRFS_INODE_NODATASUM | BTRFS_INODE_NODATACOW;
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(fs_info->tree_root, path,
block_group->start);
if (IS_ERR(inode))
return inode;
spin_lock(&block_group->lock);
if (!((BTRFS_I(inode)->flags & flags) == flags)) {
btrfs_info(fs_info, "Old style space inode found, converting.");
BTRFS_I(inode)->flags |= BTRFS_INODE_NODATASUM |
BTRFS_INODE_NODATACOW;
block_group->disk_cache_state = BTRFS_DC_CLEAR;
}
if (!test_and_set_bit(BLOCK_GROUP_FLAG_IREF, &block_group->runtime_flags))
block_group->inode = igrab(inode);
spin_unlock(&block_group->lock);
return inode;
}
static int __create_free_space_inode(struct btrfs_root *root,
struct btrfs_trans_handle *trans,
struct btrfs_path *path,
u64 ino, u64 offset)
{
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;
/* We inline CRCs for the free disk space cache */
const u64 flags = BTRFS_INODE_NOCOMPRESS | BTRFS_INODE_PREALLOC |
BTRFS_INODE_NODATASUM | BTRFS_INODE_NODATACOW;
int ret;
ret = btrfs_insert_empty_inode(trans, root, path, ino);
if (ret)
return ret;
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]);
memzero_extent_buffer(leaf, (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);
btrfs_set_inode_flags(leaf, inode_item, flags);
btrfs_set_inode_nlink(leaf, inode_item, 1);
btrfs_set_inode_transid(leaf, inode_item, trans->transid);
btrfs_set_inode_block_group(leaf, inode_item, offset);
btrfs_mark_buffer_dirty(trans, leaf);
btrfs_release_path(path);
key.objectid = BTRFS_FREE_SPACE_OBJECTID;
key.offset = offset;
key.type = 0;
ret = btrfs_insert_empty_item(trans, root, path, &key,
sizeof(struct btrfs_free_space_header));
if (ret < 0) {
btrfs_release_path(path);
return ret;
}
leaf = path->nodes[0];
header = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_free_space_header);
memzero_extent_buffer(leaf, (unsigned long)header, sizeof(*header));
btrfs_set_free_space_key(leaf, header, &disk_key);
btrfs_mark_buffer_dirty(trans, leaf);
btrfs_release_path(path);
return 0;
}
int create_free_space_inode(struct btrfs_trans_handle *trans,
struct btrfs_block_group *block_group,
struct btrfs_path *path)
{
int ret;
u64 ino;
ret = btrfs_get_free_objectid(trans->fs_info->tree_root, &ino);
if (ret < 0)
return ret;
return __create_free_space_inode(trans->fs_info->tree_root, trans, path,
ino, block_group->start);
}
/*
* inode is an optional sink: if it is NULL, btrfs_remove_free_space_inode
* handles lookup, otherwise it takes ownership and iputs the inode.
* Don't reuse an inode pointer after passing it into this function.
*/
int btrfs_remove_free_space_inode(struct btrfs_trans_handle *trans,
struct inode *inode,
struct btrfs_block_group *block_group)
{
struct btrfs_path *path;
struct btrfs_key key;
int ret = 0;
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
if (!inode)
inode = lookup_free_space_inode(block_group, path);
if (IS_ERR(inode)) {
if (PTR_ERR(inode) != -ENOENT)
ret = PTR_ERR(inode);
goto out;
}
ret = btrfs_orphan_add(trans, BTRFS_I(inode));
if (ret) {
btrfs_add_delayed_iput(BTRFS_I(inode));
goto out;
}
clear_nlink(inode);
/* One for the block groups ref */
spin_lock(&block_group->lock);
if (test_and_clear_bit(BLOCK_GROUP_FLAG_IREF, &block_group->runtime_flags)) {
block_group->inode = NULL;
spin_unlock(&block_group->lock);
iput(inode);
} else {
spin_unlock(&block_group->lock);
}
/* One for the lookup ref */
btrfs_add_delayed_iput(BTRFS_I(inode));
key.objectid = BTRFS_FREE_SPACE_OBJECTID;
key.type = 0;
key.offset = block_group->start;
ret = btrfs_search_slot(trans, trans->fs_info->tree_root, &key, path,
-1, 1);
if (ret) {
if (ret > 0)
ret = 0;
goto out;
}
ret = btrfs_del_item(trans, trans->fs_info->tree_root, path);
out:
btrfs_free_path(path);
return ret;
}
int btrfs_truncate_free_space_cache(struct btrfs_trans_handle *trans,
struct btrfs_block_group *block_group,
struct inode *vfs_inode)
{
struct btrfs_truncate_control control = {
.inode = BTRFS_I(vfs_inode),
.new_size = 0,
.ino = btrfs_ino(BTRFS_I(vfs_inode)),
.min_type = BTRFS_EXTENT_DATA_KEY,
.clear_extent_range = true,
};
struct btrfs_inode *inode = BTRFS_I(vfs_inode);
struct btrfs_root *root = inode->root;
struct extent_state *cached_state = NULL;
int ret = 0;
bool locked = false;
if (block_group) {
struct btrfs_path *path = btrfs_alloc_path();
if (!path) {
ret = -ENOMEM;
goto fail;
}
locked = true;
mutex_lock(&trans->transaction->cache_write_mutex);
if (!list_empty(&block_group->io_list)) {
list_del_init(&block_group->io_list);
btrfs_wait_cache_io(trans, block_group, path);
btrfs_put_block_group(block_group);
}
/*
* now that we've truncated the cache away, its no longer
* setup or written
*/
spin_lock(&block_group->lock);
block_group->disk_cache_state = BTRFS_DC_CLEAR;
spin_unlock(&block_group->lock);
btrfs_free_path(path);
}
btrfs_i_size_write(inode, 0);
truncate_pagecache(vfs_inode, 0);
lock_extent(&inode->io_tree, 0, (u64)-1, &cached_state);
btrfs_drop_extent_map_range(inode, 0, (u64)-1, false);
/*
* We skip the throttling logic for free space cache inodes, so we don't
* need to check for -EAGAIN.
*/
ret = btrfs_truncate_inode_items(trans, root, &control);
inode_sub_bytes(&inode->vfs_inode, control.sub_bytes);
btrfs_inode_safe_disk_i_size_write(inode, control.last_size);
unlock_extent(&inode->io_tree, 0, (u64)-1, &cached_state);
if (ret)
goto fail;
ret = btrfs_update_inode(trans, inode);
fail:
if (locked)
mutex_unlock(&trans->transaction->cache_write_mutex);
if (ret)
btrfs_abort_transaction(trans, ret);
return ret;
}
static void readahead_cache(struct inode *inode)
{
struct file_ra_state ra;
unsigned long last_index;
file_ra_state_init(&ra, inode->i_mapping);
last_index = (i_size_read(inode) - 1) >> PAGE_SHIFT;
page_cache_sync_readahead(inode->i_mapping, &ra, NULL, 0, last_index);
}
static int io_ctl_init(struct btrfs_io_ctl *io_ctl, struct inode *inode,
int write)
{
int num_pages;
num_pages = DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE);
/* Make sure we can fit our crcs and generation into the first page */
if (write && (num_pages * sizeof(u32) + sizeof(u64)) > PAGE_SIZE)
return -ENOSPC;
memset(io_ctl, 0, sizeof(struct btrfs_io_ctl));
io_ctl->pages = kcalloc(num_pages, sizeof(struct page *), GFP_NOFS);
if (!io_ctl->pages)
return -ENOMEM;
io_ctl->num_pages = num_pages;
io_ctl->fs_info = btrfs_sb(inode->i_sb);
io_ctl->inode = inode;
return 0;
}
ALLOW_ERROR_INJECTION(io_ctl_init, ERRNO);
static void io_ctl_free(struct btrfs_io_ctl *io_ctl)
{
kfree(io_ctl->pages);
io_ctl->pages = NULL;
}
static void io_ctl_unmap_page(struct btrfs_io_ctl *io_ctl)
{
if (io_ctl->cur) {
io_ctl->cur = NULL;
io_ctl->orig = NULL;
}
}
static void io_ctl_map_page(struct btrfs_io_ctl *io_ctl, int clear)
{
ASSERT(io_ctl->index < io_ctl->num_pages);
io_ctl->page = io_ctl->pages[io_ctl->index++];
io_ctl->cur = page_address(io_ctl->page);
io_ctl->orig = io_ctl->cur;
io_ctl->size = PAGE_SIZE;
if (clear)
clear_page(io_ctl->cur);
}
static void io_ctl_drop_pages(struct btrfs_io_ctl *io_ctl)
{
int i;
io_ctl_unmap_page(io_ctl);
for (i = 0; i < io_ctl->num_pages; i++) {
if (io_ctl->pages[i]) {
btrfs_folio_clear_checked(io_ctl->fs_info,
page_folio(io_ctl->pages[i]),
page_offset(io_ctl->pages[i]),
PAGE_SIZE);
unlock_page(io_ctl->pages[i]);
put_page(io_ctl->pages[i]);
}
}
}
static int io_ctl_prepare_pages(struct btrfs_io_ctl *io_ctl, bool uptodate)
{
struct page *page;
struct inode *inode = io_ctl->inode;
gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
int i;
for (i = 0; i < io_ctl->num_pages; i++) {
int ret;
page = find_or_create_page(inode->i_mapping, i, mask);
if (!page) {
io_ctl_drop_pages(io_ctl);
return -ENOMEM;
}
ret = set_page_extent_mapped(page);
if (ret < 0) {
unlock_page(page);
put_page(page);
io_ctl_drop_pages(io_ctl);
return ret;
}
io_ctl->pages[i] = page;
if (uptodate && !PageUptodate(page)) {
btrfs_read_folio(NULL, page_folio(page));
lock_page(page);
if (page->mapping != inode->i_mapping) {
btrfs_err(BTRFS_I(inode)->root->fs_info,
"free space cache page truncated");
io_ctl_drop_pages(io_ctl);
return -EIO;
}
if (!PageUptodate(page)) {
btrfs_err(BTRFS_I(inode)->root->fs_info,
"error reading free space cache");
io_ctl_drop_pages(io_ctl);
return -EIO;
}
}
}
for (i = 0; i < io_ctl->num_pages; i++)
clear_page_dirty_for_io(io_ctl->pages[i]);
return 0;
}
static void io_ctl_set_generation(struct btrfs_io_ctl *io_ctl, u64 generation)
{
io_ctl_map_page(io_ctl, 1);
/*
* Skip the csum areas. If we don't check crcs then we just have a
* 64bit chunk at the front of the first page.
*/
io_ctl->cur += (sizeof(u32) * io_ctl->num_pages);
io_ctl->size -= sizeof(u64) + (sizeof(u32) * io_ctl->num_pages);
put_unaligned_le64(generation, io_ctl->cur);
io_ctl->cur += sizeof(u64);
}
static int io_ctl_check_generation(struct btrfs_io_ctl *io_ctl, u64 generation)
{
u64 cache_gen;
/*
* Skip the crc area. If we don't check crcs then we just have a 64bit
* chunk at the front of the first page.
*/
io_ctl->cur += sizeof(u32) * io_ctl->num_pages;
io_ctl->size -= sizeof(u64) + (sizeof(u32) * io_ctl->num_pages);
cache_gen = get_unaligned_le64(io_ctl->cur);
if (cache_gen != generation) {
btrfs_err_rl(io_ctl->fs_info,
"space cache generation (%llu) does not match inode (%llu)",
cache_gen, generation);
io_ctl_unmap_page(io_ctl);
return -EIO;
}
io_ctl->cur += sizeof(u64);
return 0;
}
static void io_ctl_set_crc(struct btrfs_io_ctl *io_ctl, int index)
{
u32 *tmp;
u32 crc = ~(u32)0;
unsigned offset = 0;
if (index == 0)
offset = sizeof(u32) * io_ctl->num_pages;
crc = crc32c(crc, io_ctl->orig + offset, PAGE_SIZE - offset);
btrfs_crc32c_final(crc, (u8 *)&crc);
io_ctl_unmap_page(io_ctl);
tmp = page_address(io_ctl->pages[0]);
tmp += index;
*tmp = crc;
}
static int io_ctl_check_crc(struct btrfs_io_ctl *io_ctl, int index)
{
u32 *tmp, val;
u32 crc = ~(u32)0;
unsigned offset = 0;
if (index == 0)
offset = sizeof(u32) * io_ctl->num_pages;
tmp = page_address(io_ctl->pages[0]);
tmp += index;
val = *tmp;
io_ctl_map_page(io_ctl, 0);
crc = crc32c(crc, io_ctl->orig + offset, PAGE_SIZE - offset);
btrfs_crc32c_final(crc, (u8 *)&crc);
if (val != crc) {
btrfs_err_rl(io_ctl->fs_info,
"csum mismatch on free space cache");
io_ctl_unmap_page(io_ctl);
return -EIO;
}
return 0;
}
static int io_ctl_add_entry(struct btrfs_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;
put_unaligned_le64(offset, &entry->offset);
put_unaligned_le64(bytes, &entry->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;
io_ctl_set_crc(io_ctl, io_ctl->index - 1);
/* 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 btrfs_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) {
io_ctl_set_crc(io_ctl, io_ctl->index - 1);
if (io_ctl->index >= io_ctl->num_pages)
return -ENOSPC;
io_ctl_map_page(io_ctl, 0);
}
copy_page(io_ctl->cur, bitmap);
io_ctl_set_crc(io_ctl, io_ctl->index - 1);
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 btrfs_io_ctl *io_ctl)
{
/*
* 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);
while (io_ctl->index < io_ctl->num_pages) {
io_ctl_map_page(io_ctl, 1);
io_ctl_set_crc(io_ctl, io_ctl->index - 1);
}
}
static int io_ctl_read_entry(struct btrfs_io_ctl *io_ctl,
struct btrfs_free_space *entry, u8 *type)
{
struct btrfs_free_space_entry *e;
int ret;
if (!io_ctl->cur) {
ret = io_ctl_check_crc(io_ctl, io_ctl->index);
if (ret)
return ret;
}
e = io_ctl->cur;
entry->offset = get_unaligned_le64(&e->offset);
entry->bytes = get_unaligned_le64(&e->bytes);
*type = e->type;
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;
io_ctl_unmap_page(io_ctl);
return 0;
}
static int io_ctl_read_bitmap(struct btrfs_io_ctl *io_ctl,
struct btrfs_free_space *entry)
{
int ret;
ret = io_ctl_check_crc(io_ctl, io_ctl->index);
if (ret)
return ret;
copy_page(entry->bitmap, io_ctl->cur);
io_ctl_unmap_page(io_ctl);
return 0;
}
static void recalculate_thresholds(struct btrfs_free_space_ctl *ctl)
{
struct btrfs_block_group *block_group = ctl->block_group;
u64 max_bytes;
u64 bitmap_bytes;
u64 extent_bytes;
u64 size = block_group->length;
u64 bytes_per_bg = BITS_PER_BITMAP * ctl->unit;
u64 max_bitmaps = div64_u64(size + bytes_per_bg - 1, bytes_per_bg);
max_bitmaps = max_t(u64, max_bitmaps, 1);
if (ctl->total_bitmaps > max_bitmaps)
btrfs_err(block_group->fs_info,
"invalid free space control: bg start=%llu len=%llu total_bitmaps=%u unit=%u max_bitmaps=%llu bytes_per_bg=%llu",
block_group->start, block_group->length,
ctl->total_bitmaps, ctl->unit, max_bitmaps,
bytes_per_bg);
ASSERT(ctl->total_bitmaps <= max_bitmaps);
/*
* We are trying to keep the total amount of memory used per 1GiB of
* space to be MAX_CACHE_BYTES_PER_GIG. However, with a reclamation
* mechanism of pulling extents >= FORCE_EXTENT_THRESHOLD out of
* bitmaps, we may end up using more memory than this.
*/
if (size < SZ_1G)
max_bytes = MAX_CACHE_BYTES_PER_GIG;
else
max_bytes = MAX_CACHE_BYTES_PER_GIG * div_u64(size, SZ_1G);
bitmap_bytes = ctl->total_bitmaps * ctl->unit;
/*
* we want the extent entry threshold to always be at most 1/2 the max
* bytes we can have, or whatever is less than that.
*/
extent_bytes = max_bytes - bitmap_bytes;
extent_bytes = min_t(u64, extent_bytes, max_bytes >> 1);
ctl->extents_thresh =
div_u64(extent_bytes, sizeof(struct btrfs_free_space));
}
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)
{
struct btrfs_fs_info *fs_info = root->fs_info;
struct btrfs_free_space_header *header;
struct extent_buffer *leaf;
struct btrfs_io_ctl io_ctl;
struct btrfs_key key;
struct btrfs_free_space *e, *n;
LIST_HEAD(bitmaps);
u64 num_entries;
u64 num_bitmaps;
u64 generation;
u8 type;
int ret = 0;
/* Nothing in the space cache, goodbye */
if (!i_size_read(inode))
return 0;
key.objectid = BTRFS_FREE_SPACE_OBJECTID;
key.offset = offset;
key.type = 0;
ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
if (ret < 0)
return 0;
else if (ret > 0) {
btrfs_release_path(path);
return 0;
}
ret = -1;
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);
btrfs_release_path(path);
if (!BTRFS_I(inode)->generation) {
btrfs_info(fs_info,
"the free space cache file (%llu) is invalid, skip it",
offset);
return 0;
}
if (BTRFS_I(inode)->generation != generation) {
btrfs_err(fs_info,
"free space inode generation (%llu) did not match free space cache generation (%llu)",
BTRFS_I(inode)->generation, generation);
return 0;
}
if (!num_entries)
return 0;
ret = io_ctl_init(&io_ctl, inode, 0);
if (ret)
return ret;
readahead_cache(inode);
ret = io_ctl_prepare_pages(&io_ctl, true);
if (ret)
goto out;
ret = io_ctl_check_crc(&io_ctl, 0);
if (ret)
goto free_cache;
ret = io_ctl_check_generation(&io_ctl, generation);
if (ret)
goto free_cache;
while (num_entries) {
e = kmem_cache_zalloc(btrfs_free_space_cachep,
GFP_NOFS);
if (!e) {
ret = -ENOMEM;
goto free_cache;
}
ret = io_ctl_read_entry(&io_ctl, e, &type);
if (ret) {
kmem_cache_free(btrfs_free_space_cachep, e);
goto free_cache;
}
if (!e->bytes) {
ret = -1;
kmem_cache_free(btrfs_free_space_cachep, e);
goto free_cache;
}
if (type == BTRFS_FREE_SPACE_EXTENT) {
spin_lock(&ctl->tree_lock);
ret = link_free_space(ctl, e);
spin_unlock(&ctl->tree_lock);
if (ret) {
btrfs_err(fs_info,
"Duplicate entries in free space cache, dumping");
kmem_cache_free(btrfs_free_space_cachep, e);
goto free_cache;
}
} else {
ASSERT(num_bitmaps);
num_bitmaps--;
e->bitmap = kmem_cache_zalloc(
btrfs_free_space_bitmap_cachep, GFP_NOFS);
if (!e->bitmap) {
ret = -ENOMEM;
kmem_cache_free(
btrfs_free_space_cachep, e);
goto free_cache;
}
spin_lock(&ctl->tree_lock);
ret = link_free_space(ctl, e);
if (ret) {
spin_unlock(&ctl->tree_lock);
btrfs_err(fs_info,
"Duplicate entries in free space cache, dumping");
kmem_cache_free(btrfs_free_space_cachep, e);
goto free_cache;
}
ctl->total_bitmaps++;
recalculate_thresholds(ctl);
spin_unlock(&ctl->tree_lock);
list_add_tail(&e->list, &bitmaps);
}
num_entries--;
}
io_ctl_unmap_page(&io_ctl);
/*
* 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) {
list_del_init(&e->list);
ret = io_ctl_read_bitmap(&io_ctl, e);
if (ret)
goto free_cache;
}
io_ctl_drop_pages(&io_ctl);
ret = 1;
out:
io_ctl_free(&io_ctl);
return ret;
free_cache:
io_ctl_drop_pages(&io_ctl);
spin_lock(&ctl->tree_lock);
__btrfs_remove_free_space_cache(ctl);
spin_unlock(&ctl->tree_lock);
goto out;
}
static int copy_free_space_cache(struct btrfs_block_group *block_group,
struct btrfs_free_space_ctl *ctl)
{
struct btrfs_free_space *info;
struct rb_node *n;
int ret = 0;
while (!ret && (n = rb_first(&ctl->free_space_offset)) != NULL) {
info = rb_entry(n, struct btrfs_free_space, offset_index);
if (!info->bitmap) {
const u64 offset = info->offset;
const u64 bytes = info->bytes;
unlink_free_space(ctl, info, true);
spin_unlock(&ctl->tree_lock);
kmem_cache_free(btrfs_free_space_cachep, info);
ret = btrfs_add_free_space(block_group, offset, bytes);
spin_lock(&ctl->tree_lock);
} else {
u64 offset = info->offset;
u64 bytes = ctl->unit;
ret = search_bitmap(ctl, info, &offset, &bytes, false);
if (ret == 0) {
bitmap_clear_bits(ctl, info, offset, bytes, true);
spin_unlock(&ctl->tree_lock);
ret = btrfs_add_free_space(block_group, offset,
bytes);
spin_lock(&ctl->tree_lock);
} else {
free_bitmap(ctl, info);
ret = 0;
}
}
cond_resched_lock(&ctl->tree_lock);
}
return ret;
}
static struct lock_class_key btrfs_free_space_inode_key;
int load_free_space_cache(struct btrfs_block_group *block_group)
{
struct btrfs_fs_info *fs_info = block_group->fs_info;
struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
struct btrfs_free_space_ctl tmp_ctl = {};
struct inode *inode;
struct btrfs_path *path;
int ret = 0;
bool matched;
u64 used = block_group->used;
/*
* Because we could potentially discard our loaded free space, we want
* to load everything into a temporary structure first, and then if it's
* valid copy it all into the actual free space ctl.
*/
btrfs_init_free_space_ctl(block_group, &tmp_ctl);
/*
* 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.
*/
spin_lock(&block_group->lock);
if (block_group->disk_cache_state != BTRFS_DC_WRITTEN) {
spin_unlock(&block_group->lock);
return 0;
}
spin_unlock(&block_group->lock);
path = btrfs_alloc_path();
if (!path)
return 0;
path->search_commit_root = 1;
path->skip_locking = 1;
/*
* We must pass a path with search_commit_root set to btrfs_iget in
* order to avoid a deadlock when allocating extents for the tree root.
*
* When we are COWing an extent buffer from the tree root, when looking
* for a free extent, at extent-tree.c:find_free_extent(), we can find
* block group without its free space cache loaded. When we find one
* we must load its space cache which requires reading its free space
* cache's inode item from the root tree. If this inode item is located
* in the same leaf that we started COWing before, then we end up in
* deadlock on the extent buffer (trying to read lock it when we
* previously write locked it).
*
* It's safe to read the inode item using the commit root because
* block groups, once loaded, stay in memory forever (until they are
* removed) as well as their space caches once loaded. New block groups
* once created get their ->cached field set to BTRFS_CACHE_FINISHED so
* we will never try to read their inode item while the fs is mounted.
*/
inode = lookup_free_space_inode(block_group, path);
if (IS_ERR(inode)) {
btrfs_free_path(path);
return 0;
}
/* 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);
btrfs_free_path(path);
goto out;
}
spin_unlock(&block_group->lock);
/*
* Reinitialize the class of struct inode's mapping->invalidate_lock for
* free space inodes to prevent false positives related to locks for normal
* inodes.
*/
lockdep_set_class(&(&inode->i_data)->invalidate_lock,
&btrfs_free_space_inode_key);
ret = __load_free_space_cache(fs_info->tree_root, inode, &tmp_ctl,
path, block_group->start);
btrfs_free_path(path);
if (ret <= 0)
goto out;
matched = (tmp_ctl.free_space == (block_group->length - used -
block_group->bytes_super));
if (matched) {
spin_lock(&tmp_ctl.tree_lock);
ret = copy_free_space_cache(block_group, &tmp_ctl);
spin_unlock(&tmp_ctl.tree_lock);
/*
* ret == 1 means we successfully loaded the free space cache,
* so we need to re-set it here.
*/
if (ret == 0)
ret = 1;
} else {
/*
* We need to call the _locked variant so we don't try to update
* the discard counters.
*/
spin_lock(&tmp_ctl.tree_lock);
__btrfs_remove_free_space_cache(&tmp_ctl);
spin_unlock(&tmp_ctl.tree_lock);
btrfs_warn(fs_info,
"block group %llu has wrong amount of free space",
block_group->start);
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);
ret = 0;
btrfs_warn(fs_info,
"failed to load free space cache for block group %llu, rebuilding it now",
block_group->start);
}
spin_lock(&ctl->tree_lock);
btrfs_discard_update_discardable(block_group);
spin_unlock(&ctl->tree_lock);
iput(inode);
return ret;
}
static noinline_for_stack
int write_cache_extent_entries(struct btrfs_io_ctl *io_ctl,
struct btrfs_free_space_ctl *ctl,
struct btrfs_block_group *block_group,
int *entries, int *bitmaps,
struct list_head *bitmap_list)
{
int ret;
struct btrfs_free_cluster *cluster = NULL;
struct btrfs_free_cluster *cluster_locked = NULL;
struct rb_node *node = rb_first(&ctl->free_space_offset);
struct btrfs_trim_range *trim_entry;
/* Get the cluster for this block_group if it exists */
if (block_group && !list_empty(&block_group->cluster_list)) {
cluster = list_entry(block_group->cluster_list.next,
struct btrfs_free_cluster,
block_group_list);
}
if (!node && cluster) {
cluster_locked = cluster;
spin_lock(&cluster_locked->lock);
node = rb_first(&cluster->root);
cluster = NULL;
}
/* Write out the extent entries */
while (node) {
struct btrfs_free_space *e;
e = rb_entry(node, struct btrfs_free_space, offset_index);
*entries += 1;
ret = io_ctl_add_entry(io_ctl, e->offset, e->bytes,
e->bitmap);
if (ret)
goto fail;
if (e->bitmap) {
list_add_tail(&e->list, bitmap_list);
*bitmaps += 1;
}
node = rb_next(node);
if (!node && cluster) {
node = rb_first(&cluster->root);
cluster_locked = cluster;
spin_lock(&cluster_locked->lock);
cluster = NULL;
}
}
if (cluster_locked) {
spin_unlock(&cluster_locked->lock);
cluster_locked = NULL;
}
/*
* Make sure we don't miss any range that was removed from our rbtree
* because trimming is running. Otherwise after a umount+mount (or crash
* after committing the transaction) we would leak free space and get
* an inconsistent free space cache report from fsck.
*/
list_for_each_entry(trim_entry, &ctl->trimming_ranges, list) {
ret = io_ctl_add_entry(io_ctl, trim_entry->start,
trim_entry->bytes, NULL);
if (ret)
goto fail;
*entries += 1;
}
return 0;
fail:
if (cluster_locked)
spin_unlock(&cluster_locked->lock);
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_DELALLOC, NULL);
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_DELALLOC,
NULL);
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(trans, leaf);
btrfs_release_path(path);
return 0;
fail:
return -1;
}
static noinline_for_stack int write_pinned_extent_entries(
struct btrfs_trans_handle *trans,
struct btrfs_block_group *block_group,
struct btrfs_io_ctl *io_ctl,
int *entries)
{
u64 start, extent_start, extent_end, len;
struct extent_io_tree *unpin = NULL;
int ret;
if (!block_group)
return 0;
/*
* We want to add any pinned extents to our free space cache
* so we don't leak the space
*
* We shouldn't have switched the pinned extents yet so this is the
* right one
*/
unpin = &trans->transaction->pinned_extents;
start = block_group->start;
while (start < block_group->start + block_group->length) {
if (!find_first_extent_bit(unpin, start,
&extent_start, &extent_end,
EXTENT_DIRTY, NULL))
return 0;
/* This pinned extent is out of our range */
if (extent_start >= block_group->start + block_group->length)
return 0;
extent_start = max(extent_start, start);
extent_end = min(block_group->start + block_group->length,
extent_end + 1);
len = extent_end - extent_start;
*entries += 1;
ret = io_ctl_add_entry(io_ctl, extent_start, len, NULL);
if (ret)
return -ENOSPC;
start = extent_end;
}
return 0;
}
static noinline_for_stack int
write_bitmap_entries(struct btrfs_io_ctl *io_ctl, struct list_head *bitmap_list)
{
struct btrfs_free_space *entry, *next;
int ret;
/* Write out the bitmaps */
list_for_each_entry_safe(entry, next, bitmap_list, list) {
ret = io_ctl_add_bitmap(io_ctl, entry->bitmap);
if (ret)
return -ENOSPC;
list_del_init(&entry->list);
}
return 0;
}
static int flush_dirty_cache(struct inode *inode)
{
int ret;
ret = btrfs_wait_ordered_range(inode, 0, (u64)-1);
if (ret)
clear_extent_bit(&BTRFS_I(inode)->io_tree, 0, inode->i_size - 1,
EXTENT_DELALLOC, NULL);
return ret;
}
static void noinline_for_stack
cleanup_bitmap_list(struct list_head *bitmap_list)
{
struct btrfs_free_space *entry, *next;
list_for_each_entry_safe(entry, next, bitmap_list, list)
list_del_init(&entry->list);
}
static void noinline_for_stack
cleanup_write_cache_enospc(struct inode *inode,
struct btrfs_io_ctl *io_ctl,
struct extent_state **cached_state)
{
io_ctl_drop_pages(io_ctl);
unlock_extent(&BTRFS_I(inode)->io_tree, 0, i_size_read(inode) - 1,
cached_state);
}
static int __btrfs_wait_cache_io(struct btrfs_root *root,
struct btrfs_trans_handle *trans,
struct btrfs_block_group *block_group,
struct btrfs_io_ctl *io_ctl,
struct btrfs_path *path, u64 offset)
{
int ret;
struct inode *inode = io_ctl->inode;
if (!inode)
return 0;
/* Flush the dirty pages in the cache file. */
ret = flush_dirty_cache(inode);
if (ret)
goto out;
/* Update the cache item to tell everyone this cache file is valid. */
ret = update_cache_item(trans, root, inode, path, offset,
io_ctl->entries, io_ctl->bitmaps);
out:
if (ret) {
invalidate_inode_pages2(inode->i_mapping);
BTRFS_I(inode)->generation = 0;
if (block_group)
btrfs_debug(root->fs_info,
"failed to write free space cache for block group %llu error %d",
block_group->start, ret);
}
btrfs_update_inode(trans, BTRFS_I(inode));
if (block_group) {
/* the dirty list is protected by the dirty_bgs_lock */
spin_lock(&trans->transaction->dirty_bgs_lock);
/* the disk_cache_state is protected by the block group lock */
spin_lock(&block_group->lock);
/*
* only mark this as written if we didn't get put back on
* the dirty list while waiting for IO. Otherwise our
* cache state won't be right, and we won't get written again
*/
if (!ret && list_empty(&block_group->dirty_list))
block_group->disk_cache_state = BTRFS_DC_WRITTEN;
else if (ret)
block_group->disk_cache_state = BTRFS_DC_ERROR;
spin_unlock(&block_group->lock);
spin_unlock(&trans->transaction->dirty_bgs_lock);
io_ctl->inode = NULL;
iput(inode);
}
return ret;
}
int btrfs_wait_cache_io(struct btrfs_trans_handle *trans,
struct btrfs_block_group *block_group,
struct btrfs_path *path)
{
return __btrfs_wait_cache_io(block_group->fs_info->tree_root, trans,
block_group, &block_group->io_ctl,
path, block_group->start);
}
/*
* Write out cached info to an inode.
*
* @inode: freespace inode we are writing out
* @ctl: free space cache we are going to write out
* @block_group: block_group for this cache if it belongs to a block_group
* @io_ctl: holds context for the io
* @trans: the trans handle
*
* This function writes out a free space cache struct to disk for quick recovery
* on mount. This will return 0 if it was successful in writing the cache out,
* or an errno if it was not.
*/
static int __btrfs_write_out_cache(struct inode *inode,
struct btrfs_free_space_ctl *ctl,
struct btrfs_block_group *block_group,
struct btrfs_io_ctl *io_ctl,
struct btrfs_trans_handle *trans)
{
struct extent_state *cached_state = NULL;
LIST_HEAD(bitmap_list);
int entries = 0;
int bitmaps = 0;
int ret;
int must_iput = 0;
if (!i_size_read(inode))
return -EIO;
WARN_ON(io_ctl->pages);
ret = io_ctl_init(io_ctl, inode, 1);
if (ret)
return ret;
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;
must_iput = 1;
goto out;
}
spin_unlock(&block_group->lock);
}
/* Lock all pages first so we can lock the extent safely. */
ret = io_ctl_prepare_pages(io_ctl, false);
if (ret)
goto out_unlock;
lock_extent(&BTRFS_I(inode)->io_tree, 0, i_size_read(inode) - 1,
&cached_state);
io_ctl_set_generation(io_ctl, trans->transid);
mutex_lock(&ctl->cache_writeout_mutex);
/* Write out the extent entries in the free space cache */
spin_lock(&ctl->tree_lock);
ret = write_cache_extent_entries(io_ctl, ctl,
block_group, &entries, &bitmaps,
&bitmap_list);
if (ret)
goto out_nospc_locked;
/*
* 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.
*
* If this changes while we are working we'll get added back to
* the dirty list and redo it. No locking needed
*/
ret = write_pinned_extent_entries(trans, block_group, io_ctl, &entries);
if (ret)
goto out_nospc_locked;
/*
* At last, we write out all the bitmaps and keep cache_writeout_mutex
* locked while doing it because a concurrent trim can be manipulating
* or freeing the bitmap.
*/
ret = write_bitmap_entries(io_ctl, &bitmap_list);
spin_unlock(&ctl->tree_lock);
mutex_unlock(&ctl->cache_writeout_mutex);
if (ret)
goto out_nospc;
/* Zero out the rest of the pages just to make sure */
io_ctl_zero_remaining_pages(io_ctl);
/* Everything is written out, now we dirty the pages in the file. */
ret = btrfs_dirty_pages(BTRFS_I(inode), io_ctl->pages,
io_ctl->num_pages, 0, i_size_read(inode),
&cached_state, false);
if (ret)
goto out_nospc;
if (block_group && (block_group->flags & BTRFS_BLOCK_GROUP_DATA))
up_write(&block_group->data_rwsem);
/*
* Release the pages and unlock the extent, we will flush
* them out later
*/
io_ctl_drop_pages(io_ctl);
io_ctl_free(io_ctl);
unlock_extent(&BTRFS_I(inode)->io_tree, 0, i_size_read(inode) - 1,
&cached_state);
/*
* at this point the pages are under IO and we're happy,
* The caller is responsible for waiting on them and updating
* the cache and the inode
*/
io_ctl->entries = entries;
io_ctl->bitmaps = bitmaps;
ret = btrfs_fdatawrite_range(inode, 0, (u64)-1);
if (ret)
goto out;
return 0;
out_nospc_locked:
cleanup_bitmap_list(&bitmap_list);
spin_unlock(&ctl->tree_lock);
mutex_unlock(&ctl->cache_writeout_mutex);
out_nospc:
cleanup_write_cache_enospc(inode, io_ctl, &cached_state);
out_unlock:
if (block_group && (block_group->flags & BTRFS_BLOCK_GROUP_DATA))
up_write(&block_group->data_rwsem);
out:
io_ctl->inode = NULL;
io_ctl_free(io_ctl);
if (ret) {
invalidate_inode_pages2(inode->i_mapping);
BTRFS_I(inode)->generation = 0;
}
btrfs_update_inode(trans, BTRFS_I(inode));
if (must_iput)
iput(inode);
return ret;
}
int btrfs_write_out_cache(struct btrfs_trans_handle *trans,
struct btrfs_block_group *block_group,
struct btrfs_path *path)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
struct inode *inode;
int ret = 0;
spin_lock(&block_group->lock);
if (block_group->disk_cache_state < BTRFS_DC_SETUP) {
spin_unlock(&block_group->lock);
return 0;
}
spin_unlock(&block_group->lock);
inode = lookup_free_space_inode(block_group, path);
if (IS_ERR(inode))
return 0;
ret = __btrfs_write_out_cache(inode, ctl, block_group,
&block_group->io_ctl, trans);
if (ret) {
btrfs_debug(fs_info,
"failed to write free space cache for block group %llu error %d",
block_group->start, ret);
spin_lock(&block_group->lock);
block_group->disk_cache_state = BTRFS_DC_ERROR;
spin_unlock(&block_group->lock);
block_group->io_ctl.inode = NULL;
iput(inode);
}
/*
* if ret == 0 the caller is expected to call btrfs_wait_cache_io
* to wait for IO and put the inode
*/
return ret;
}
static inline unsigned long offset_to_bit(u64 bitmap_start, u32 unit,
u64 offset)
{
ASSERT(offset >= bitmap_start);
offset -= bitmap_start;
return (unsigned long)(div_u64(offset, unit));
}
static inline unsigned long bytes_to_bits(u64 bytes, u32 unit)
{
return (unsigned long)(div_u64(bytes, unit));
}
static inline u64 offset_to_bitmap(struct btrfs_free_space_ctl *ctl,
u64 offset)
{
u64 bitmap_start;
u64 bytes_per_bitmap;
bytes_per_bitmap = BITS_PER_BITMAP * ctl->unit;
bitmap_start = offset - ctl->start;
bitmap_start = div64_u64(bitmap_start, bytes_per_bitmap);
bitmap_start *= bytes_per_bitmap;
bitmap_start += ctl->start;
return bitmap_start;
}
static int tree_insert_offset(struct btrfs_free_space_ctl *ctl,
struct btrfs_free_cluster *cluster,
struct btrfs_free_space *new_entry)
{
struct rb_root *root;
struct rb_node **p;
struct rb_node *parent = NULL;
lockdep_assert_held(&ctl->tree_lock);
if (cluster) {
lockdep_assert_held(&cluster->lock);
root = &cluster->root;
} else {
root = &ctl->free_space_offset;
}
p = &root->rb_node;
while (*p) {
struct btrfs_free_space *info;
parent = *p;
info = rb_entry(parent, struct btrfs_free_space, offset_index);
if (new_entry->offset < info->offset) {
p = &(*p)->rb_left;
} else if (new_entry->offset > info->offset) {
p = &(*p)->rb_right;
} 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 (new_entry->bitmap) {
if (info->bitmap) {
WARN_ON_ONCE(1);
return -EEXIST;
}
p = &(*p)->rb_right;
} else {
if (!info->bitmap) {
WARN_ON_ONCE(1);
return -EEXIST;
}
p = &(*p)->rb_left;
}
}
}
rb_link_node(&new_entry->offset_index, parent, p);
rb_insert_color(&new_entry->offset_index, root);
return 0;
}
/*
* This is a little subtle. We *only* have ->max_extent_size set if we actually
* searched through the bitmap and figured out the largest ->max_extent_size,
* otherwise it's 0. In the case that it's 0 we don't want to tell the
* allocator the wrong thing, we want to use the actual real max_extent_size
* we've found already if it's larger, or we want to use ->bytes.
*
* This matters because find_free_space() will skip entries who's ->bytes is
* less than the required bytes. So if we didn't search down this bitmap, we
* may pick some previous entry that has a smaller ->max_extent_size than we
* have. For example, assume we have two entries, one that has
* ->max_extent_size set to 4K and ->bytes set to 1M. A second entry hasn't set
* ->max_extent_size yet, has ->bytes set to 8K and it's contiguous. We will
* call into find_free_space(), and return with max_extent_size == 4K, because
* that first bitmap entry had ->max_extent_size set, but the second one did
* not. If instead we returned 8K we'd come in searching for 8K, and find the
* 8K contiguous range.
*
* Consider the other case, we have 2 8K chunks in that second entry and still
* don't have ->max_extent_size set. We'll return 16K, and the next time the
* allocator comes in it'll fully search our second bitmap, and this time it'll
* get an uptodate value of 8K as the maximum chunk size. Then we'll get the
* right allocation the next loop through.
*/
static inline u64 get_max_extent_size(const struct btrfs_free_space *entry)
{
if (entry->bitmap && entry->max_extent_size)
return entry->max_extent_size;
return entry->bytes;
}
/*
* We want the largest entry to be leftmost, so this is inverted from what you'd
* normally expect.
*/
static bool entry_less(struct rb_node *node, const struct rb_node *parent)
{
const struct btrfs_free_space *entry, *exist;
entry = rb_entry(node, struct btrfs_free_space, bytes_index);
exist = rb_entry(parent, struct btrfs_free_space, bytes_index);
return get_max_extent_size(exist) < get_max_extent_size(entry);
}
/*
* searches the tree for the given offset.
*
* 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.
*/
static struct btrfs_free_space *
tree_search_offset(struct btrfs_free_space_ctl *ctl,
u64 offset, int bitmap_only, int fuzzy)
{
struct rb_node *n = ctl->free_space_offset.rb_node;
struct btrfs_free_space *entry = NULL, *prev = NULL;
lockdep_assert_held(&ctl->tree_lock);
/* find entry that is closest to the 'offset' */
while (n) {
entry = rb_entry(n, struct btrfs_free_space, offset_index);
prev = entry;
if (offset < entry->offset)
n = n->rb_left;
else if (offset > entry->offset)
n = n->rb_right;
else
break;
entry = NULL;
}
if (bitmap_only) {
if (!entry)
return NULL;
if (entry->bitmap)
return entry;
/*
* 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;
WARN_ON(!entry->bitmap);
return entry;
} else if (entry) {
if (entry->bitmap) {
/*
* if previous extent entry covers the offset,
* we should return it instead of the bitmap entry
*/
n = rb_prev(&entry->offset_index);
if (n) {
prev = rb_entry(n, struct btrfs_free_space,
offset_index);
if (!prev->bitmap &&
prev->offset + prev->bytes > offset)
entry = prev;
}
}
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);
ASSERT(entry->offset <= offset);
} else {
if (fuzzy)
return entry;
else
return NULL;
}
}
if (entry->bitmap) {
n = rb_prev(&entry->offset_index);
if (n) {
prev = rb_entry(n, struct btrfs_free_space,
offset_index);
if (!prev->bitmap &&
prev->offset + prev->bytes > offset)
return prev;
}
if (entry->offset + BITS_PER_BITMAP * ctl->unit > offset)
return entry;
} else if (entry->offset + entry->bytes > offset)
return entry;
if (!fuzzy)
return NULL;
while (1) {
n = rb_next(&entry->offset_index);
if (!n)
return NULL;
entry = rb_entry(n, struct btrfs_free_space, offset_index);
if (entry->bitmap) {
if (entry->offset + BITS_PER_BITMAP *
ctl->unit > offset)
break;
} else {
if (entry->offset + entry->bytes > offset)
break;
}
}
return entry;
}
static inline void unlink_free_space(struct btrfs_free_space_ctl *ctl,
struct btrfs_free_space *info,
bool update_stat)
{
lockdep_assert_held(&ctl->tree_lock);
rb_erase(&info->offset_index, &ctl->free_space_offset);
rb_erase_cached(&info->bytes_index, &ctl->free_space_bytes);
ctl->free_extents--;
if (!info->bitmap && !btrfs_free_space_trimmed(info)) {
ctl->discardable_extents[BTRFS_STAT_CURR]--;
ctl->discardable_bytes[BTRFS_STAT_CURR] -= info->bytes;
}
if (update_stat)
ctl->free_space -= info->bytes;
}
static int link_free_space(struct btrfs_free_space_ctl *ctl,
struct btrfs_free_space *info)
{
int ret = 0;
lockdep_assert_held(&ctl->tree_lock);
ASSERT(info->bytes || info->bitmap);
ret = tree_insert_offset(ctl, NULL, info);
if (ret)
return ret;
rb_add_cached(&info->bytes_index, &ctl->free_space_bytes, entry_less);
if (!info->bitmap && !btrfs_free_space_trimmed(info)) {
ctl->discardable_extents[BTRFS_STAT_CURR]++;
ctl->discardable_bytes[BTRFS_STAT_CURR] += info->bytes;
}
ctl->free_space += info->bytes;
ctl->free_extents++;
return ret;
}
static void relink_bitmap_entry(struct btrfs_free_space_ctl *ctl,
struct btrfs_free_space *info)
{
ASSERT(info->bitmap);
/*
* If our entry is empty it's because we're on a cluster and we don't
* want to re-link it into our ctl bytes index.
*/
if (RB_EMPTY_NODE(&info->bytes_index))
return;
lockdep_assert_held(&ctl->tree_lock);
rb_erase_cached(&info->bytes_index, &ctl->free_space_bytes);
rb_add_cached(&info->bytes_index, &ctl->free_space_bytes, entry_less);
}
static inline void bitmap_clear_bits(struct btrfs_free_space_ctl *ctl,
struct btrfs_free_space *info,
u64 offset, u64 bytes, bool update_stat)
{
unsigned long start, count, end;
int extent_delta = -1;
start = offset_to_bit(info->offset, ctl->unit, offset);
count = bytes_to_bits(bytes, ctl->unit);
end = start + count;
ASSERT(end <= BITS_PER_BITMAP);
bitmap_clear(info->bitmap, start, count);
info->bytes -= bytes;
if (info->max_extent_size > ctl->unit)
info->max_extent_size = 0;
relink_bitmap_entry(ctl, info);
if (start && test_bit(start - 1, info->bitmap))
extent_delta++;
if (end < BITS_PER_BITMAP && test_bit(end, info->bitmap))
extent_delta++;
info->bitmap_extents += extent_delta;
if (!btrfs_free_space_trimmed(info)) {
ctl->discardable_extents[BTRFS_STAT_CURR] += extent_delta;
ctl->discardable_bytes[BTRFS_STAT_CURR] -= bytes;
}
if (update_stat)
ctl->free_space -= bytes;
}
static void bitmap_set_bits(struct btrfs_free_space_ctl *ctl,
struct btrfs_free_space *info, u64 offset,
u64 bytes)
{
unsigned long start, count, end;
int extent_delta = 1;
start = offset_to_bit(info->offset, ctl->unit, offset);
count = bytes_to_bits(bytes, ctl->unit);
end = start + count;
ASSERT(end <= BITS_PER_BITMAP);
bitmap_set(info->bitmap, start, count);
/*
* We set some bytes, we have no idea what the max extent size is
* anymore.
*/
info->max_extent_size = 0;
info->bytes += bytes;
ctl->free_space += bytes;
relink_bitmap_entry(ctl, info);
if (start && test_bit(start - 1, info->bitmap))
extent_delta--;
if (end < BITS_PER_BITMAP && test_bit(end, info->bitmap))
extent_delta--;
info->bitmap_extents += extent_delta;
if (!btrfs_free_space_trimmed(info)) {
ctl->discardable_extents[BTRFS_STAT_CURR] += extent_delta;
ctl->discardable_bytes[BTRFS_STAT_CURR] += bytes;
}
}
/*
* If we can not find suitable extent, we will use bytes to record
* the size of the max extent.
*/
static int search_bitmap(struct btrfs_free_space_ctl *ctl,
struct btrfs_free_space *bitmap_info, u64 *offset,
u64 *bytes, bool for_alloc)
{
unsigned long found_bits = 0;
unsigned long max_bits = 0;
unsigned long bits, i;
unsigned long next_zero;
unsigned long extent_bits;
/*
* Skip searching the bitmap if we don't have a contiguous section that
* is large enough for this allocation.
*/
if (for_alloc &&
bitmap_info->max_extent_size &&
bitmap_info->max_extent_size < *bytes) {
*bytes = bitmap_info->max_extent_size;
return -1;
}
i = offset_to_bit(bitmap_info->offset, ctl->unit,
max_t(u64, *offset, bitmap_info->offset));
bits = bytes_to_bits(*bytes, ctl->unit);
for_each_set_bit_from(i, bitmap_info->bitmap, BITS_PER_BITMAP) {
if (for_alloc && bits == 1) {
found_bits = 1;
break;
}
next_zero = find_next_zero_bit(bitmap_info->bitmap,
BITS_PER_BITMAP, i);
extent_bits = next_zero - i;
if (extent_bits >= bits) {
found_bits = extent_bits;
break;
} else if (extent_bits > max_bits) {
max_bits = extent_bits;
}
i = next_zero;
}
if (found_bits) {
*offset = (u64)(i * ctl->unit) + bitmap_info->offset;
*bytes = (u64)(found_bits) * ctl->unit;
return 0;
}
*bytes = (u64)(max_bits) * ctl->unit;
bitmap_info->max_extent_size = *bytes;
relink_bitmap_entry(ctl, bitmap_info);
return -1;
}
/* Cache the size of the max extent in bytes */
static struct btrfs_free_space *
find_free_space(struct btrfs_free_space_ctl *ctl, u64 *offset, u64 *bytes,
unsigned long align, u64 *max_extent_size, bool use_bytes_index)
{
struct btrfs_free_space *entry;
struct rb_node *node;
u64 tmp;
u64 align_off;
int ret;
if (!ctl->free_space_offset.rb_node)
goto out;
again:
if (use_bytes_index) {
node = rb_first_cached(&ctl->free_space_bytes);
} else {
entry = tree_search_offset(ctl, offset_to_bitmap(ctl, *offset),
0, 1);
if (!entry)
goto out;
node = &entry->offset_index;
}
for (; node; node = rb_next(node)) {
if (use_bytes_index)
entry = rb_entry(node, struct btrfs_free_space,
bytes_index);
else
entry = rb_entry(node, struct btrfs_free_space,
offset_index);
/*
* If we are using the bytes index then all subsequent entries
* in this tree are going to be < bytes, so simply set the max
* extent size and exit the loop.
*
* If we're using the offset index then we need to keep going
* through the rest of the tree.
*/
if (entry->bytes < *bytes) {
*max_extent_size = max(get_max_extent_size(entry),
*max_extent_size);
if (use_bytes_index)
break;
continue;
}
/* make sure the space returned is big enough
* to match our requested alignment
*/
if (*bytes >= align) {
tmp = entry->offset - ctl->start + align - 1;
tmp = div64_u64(tmp, align);
tmp = tmp * align + ctl->start;
align_off = tmp - entry->offset;
} else {
align_off = 0;
tmp = entry->offset;
}
/*
* We don't break here if we're using the bytes index because we
* may have another entry that has the correct alignment that is
* the right size, so we don't want to miss that possibility.
* At worst this adds another loop through the logic, but if we
* broke here we could prematurely ENOSPC.
*/
if (entry->bytes < *bytes + align_off) {
*max_extent_size = max(get_max_extent_size(entry),
*max_extent_size);
continue;
}
if (entry->bitmap) {
struct rb_node *old_next = rb_next(node);
u64 size = *bytes;
ret = search_bitmap(ctl, entry, &tmp, &size, true);
if (!ret) {
*offset = tmp;
*bytes = size;
return entry;
} else {
*max_extent_size =
max(get_max_extent_size(entry),
*max_extent_size);
}
/*
* The bitmap may have gotten re-arranged in the space
* index here because the max_extent_size may have been
* updated. Start from the beginning again if this
* happened.
*/
if (use_bytes_index && old_next != rb_next(node))
goto again;
continue;
}
*offset = tmp;
*bytes = entry->bytes - align_off;
return entry;
}
out:
return NULL;
}
static void add_new_bitmap(struct btrfs_free_space_ctl *ctl,
struct btrfs_free_space *info, u64 offset)
{
info->offset = offset_to_bitmap(ctl, offset);
info->bytes = 0;
info->bitmap_extents = 0;
INIT_LIST_HEAD(&info->list);
link_free_space(ctl, info);
ctl->total_bitmaps++;
recalculate_thresholds(ctl);
}
static void free_bitmap(struct btrfs_free_space_ctl *ctl,
struct btrfs_free_space *bitmap_info)
{
/*
* Normally when this is called, the bitmap is completely empty. However,
* if we are blowing up the free space cache for one reason or another
* via __btrfs_remove_free_space_cache(), then it may not be freed and
* we may leave stats on the table.
*/
if (bitmap_info->bytes && !btrfs_free_space_trimmed(bitmap_info)) {
ctl->discardable_extents[BTRFS_STAT_CURR] -=
bitmap_info->bitmap_extents;
ctl->discardable_bytes[BTRFS_STAT_CURR] -= bitmap_info->bytes;
}
unlink_free_space(ctl, bitmap_info, true);
kmem_cache_free(btrfs_free_space_bitmap_cachep, bitmap_info->bitmap);
kmem_cache_free(btrfs_free_space_cachep, bitmap_info);
ctl->total_bitmaps--;
recalculate_thresholds(ctl);
}
static noinline int remove_from_bitmap(struct btrfs_free_space_ctl *ctl,
struct btrfs_free_space *bitmap_info,
u64 *offset, u64 *bytes)
{
u64 end;
u64 search_start, search_bytes;
int ret;
again:
end = bitmap_info->offset + (u64)(BITS_PER_BITMAP * ctl->unit) - 1;
/*
* 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.
*/
search_start = *offset;
search_bytes = ctl->unit;
search_bytes = min(search_bytes, end - search_start + 1);
ret = search_bitmap(ctl, bitmap_info, &search_start, &search_bytes,
false);
if (ret < 0 || search_start != *offset)
return -EINVAL;
/* 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, true);
*offset += search_bytes;
*bytes -= search_bytes;
if (*bytes) {
struct rb_node *next = rb_next(&bitmap_info->offset_index);
if (!bitmap_info->bytes)
free_bitmap(ctl, bitmap_info);
/*
* no entry after this bitmap, but we still have bytes to
* remove, so something has gone wrong.
*/
if (!next)
return -EINVAL;
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.
*/
if (!bitmap_info->bitmap)
return -EAGAIN;
/*
* 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;
search_bytes = ctl->unit;
ret = search_bitmap(ctl, bitmap_info, &search_start,
&search_bytes, false);
if (ret < 0 || search_start != *offset)
return -EAGAIN;
goto again;
} else if (!bitmap_info->bytes)
free_bitmap(ctl, bitmap_info);
return 0;
}
static u64 add_bytes_to_bitmap(struct btrfs_free_space_ctl *ctl,
struct btrfs_free_space *info, u64 offset,
u64 bytes, enum btrfs_trim_state trim_state)
{
u64 bytes_to_set = 0;
u64 end;
/*
* This is a tradeoff to make bitmap trim state minimal. We mark the
* whole bitmap untrimmed if at any point we add untrimmed regions.
*/
if (trim_state == BTRFS_TRIM_STATE_UNTRIMMED) {
if (btrfs_free_space_trimmed(info)) {
ctl->discardable_extents[BTRFS_STAT_CURR] +=
info->bitmap_extents;
ctl->discardable_bytes[BTRFS_STAT_CURR] += info->bytes;
}
info->trim_state = BTRFS_TRIM_STATE_UNTRIMMED;
}
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;
}
static bool use_bitmap(struct btrfs_free_space_ctl *ctl,
struct btrfs_free_space *info)
{
struct btrfs_block_group *block_group = ctl->block_group;
struct btrfs_fs_info *fs_info = block_group->fs_info;
bool forced = false;
#ifdef CONFIG_BTRFS_DEBUG
if (btrfs_should_fragment_free_space(block_group))
forced = true;
#endif
/* This is a way to reclaim large regions from the bitmaps. */
if (!forced && info->bytes >= FORCE_EXTENT_THRESHOLD)
return false;
/*
* If we are below the extents threshold then we can add this as an
* extent, and don't have to deal with the bitmap
*/
if (!forced && ctl->free_extents < ctl->extents_thresh) {
/*
* 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 plenty
* 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 <= fs_info->sectorsize * 8) {
if (ctl->free_extents * 3 <= ctl->extents_thresh)
return false;
} else {
return false;
}
}
/*
* 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.
*/
if (((BITS_PER_BITMAP * ctl->unit) >> 1) > block_group->length)
return false;
return true;
}
static const struct btrfs_free_space_op free_space_op = {
.use_bitmap = use_bitmap,
};
static int insert_into_bitmap(struct btrfs_free_space_ctl *ctl,
struct btrfs_free_space *info)
{
struct btrfs_free_space *bitmap_info;
struct btrfs_block_group *block_group = NULL;
int added = 0;
u64 bytes, offset, bytes_added;
enum btrfs_trim_state trim_state;
int ret;
bytes = info->bytes;
offset = info->offset;
trim_state = info->trim_state;
if (!ctl->op->use_bitmap(ctl, info))
return 0;
if (ctl->op == &free_space_op)
block_group = ctl->block_group;
again:
/*
* 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);
goto no_cluster_bitmap;
}
entry = rb_entry(node, struct btrfs_free_space, offset_index);
if (!entry->bitmap) {
spin_unlock(&cluster->lock);
goto no_cluster_bitmap;
}
if (entry->offset == offset_to_bitmap(ctl, offset)) {
bytes_added = add_bytes_to_bitmap(ctl, entry, offset,
bytes, trim_state);
bytes -= bytes_added;
offset += bytes_added;
}
spin_unlock(&cluster->lock);
if (!bytes) {
ret = 1;
goto out;
}
}
no_cluster_bitmap:
bitmap_info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
1, 0);
if (!bitmap_info) {
ASSERT(added == 0);
goto new_bitmap;
}
bytes_added = add_bytes_to_bitmap(ctl, bitmap_info, offset, bytes,
trim_state);
bytes -= bytes_added;
offset += bytes_added;
added = 0;
if (!bytes) {
ret = 1;
goto out;
} else
goto again;
new_bitmap:
if (info && info->bitmap) {
add_new_bitmap(ctl, info, offset);
added = 1;
info = NULL;
goto again;
} else {
spin_unlock(&ctl->tree_lock);
/* no pre-allocated info, allocate a new one */
if (!info) {
info = kmem_cache_zalloc(btrfs_free_space_cachep,
GFP_NOFS);
if (!info) {
spin_lock(&ctl->tree_lock);
ret = -ENOMEM;
goto out;
}
}
/* allocate the bitmap */
info->bitmap = kmem_cache_zalloc(btrfs_free_space_bitmap_cachep,
GFP_NOFS);
info->trim_state = BTRFS_TRIM_STATE_TRIMMED;
spin_lock(&ctl->tree_lock);
if (!info->bitmap) {
ret = -ENOMEM;
goto out;
}
goto again;
}
out:
if (info) {
if (info->bitmap)
kmem_cache_free(btrfs_free_space_bitmap_cachep,
info->bitmap);
kmem_cache_free(btrfs_free_space_cachep, info);
}
return ret;
}
/*
* Free space merging rules:
* 1) Merge trimmed areas together
* 2) Let untrimmed areas coalesce with trimmed areas
* 3) Always pull neighboring regions from bitmaps
*
* The above rules are for when we merge free space based on btrfs_trim_state.
* Rules 2 and 3 are subtle because they are suboptimal, but are done for the
* same reason: to promote larger extent regions which makes life easier for
* find_free_extent(). Rule 2 enables coalescing based on the common path
* being returning free space from btrfs_finish_extent_commit(). So when free
* space is trimmed, it will prevent aggregating trimmed new region and
* untrimmed regions in the rb_tree. Rule 3 is purely to obtain larger extents
* and provide find_free_extent() with the largest extents possible hoping for
* the reuse path.
*/
static bool try_merge_free_space(struct btrfs_free_space_ctl *ctl,
struct btrfs_free_space *info, bool update_stat)
{
struct btrfs_free_space *left_info = NULL;
struct btrfs_free_space *right_info;
bool merged = false;
u64 offset = info->offset;
u64 bytes = info->bytes;
const bool is_trimmed = btrfs_free_space_trimmed(info);
struct rb_node *right_prev = NULL;
/*
* 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
*/
right_info = tree_search_offset(ctl, offset + bytes, 0, 0);
if (right_info)
right_prev = rb_prev(&right_info->offset_index);
if (right_prev)
left_info = rb_entry(right_prev, struct btrfs_free_space, offset_index);
else if (!right_info)
left_info = tree_search_offset(ctl, offset - 1, 0, 0);
/* See try_merge_free_space() comment. */
if (right_info && !right_info->bitmap &&
(!is_trimmed || btrfs_free_space_trimmed(right_info))) {
unlink_free_space(ctl, right_info, update_stat);
info->bytes += right_info->bytes;
kmem_cache_free(btrfs_free_space_cachep, right_info);
merged = true;
}
/* See try_merge_free_space() comment. */
if (left_info && !left_info->bitmap &&
left_info->offset + left_info->bytes == offset &&
(!is_trimmed || btrfs_free_space_trimmed(left_info))) {
unlink_free_space(ctl, left_info, update_stat);
info->offset = left_info->offset;
info->bytes += left_info->bytes;
kmem_cache_free(btrfs_free_space_cachep, left_info);
merged = true;
}
return merged;
}
static bool steal_from_bitmap_to_end(struct btrfs_free_space_ctl *ctl,
struct btrfs_free_space *info,
bool update_stat)
{
struct btrfs_free_space *bitmap;
unsigned long i;
unsigned long j;
const u64 end = info->offset + info->bytes;
const u64 bitmap_offset = offset_to_bitmap(ctl, end);
u64 bytes;
bitmap = tree_search_offset(ctl, bitmap_offset, 1, 0);
if (!bitmap)
return false;
i = offset_to_bit(bitmap->offset, ctl->unit, end);
j = find_next_zero_bit(bitmap->bitmap, BITS_PER_BITMAP, i);
if (j == i)
return false;
bytes = (j - i) * ctl->unit;
info->bytes += bytes;
/* See try_merge_free_space() comment. */
if (!btrfs_free_space_trimmed(bitmap))
info->trim_state = BTRFS_TRIM_STATE_UNTRIMMED;
bitmap_clear_bits(ctl, bitmap, end, bytes, update_stat);
if (!bitmap->bytes)
free_bitmap(ctl, bitmap);
return true;
}
static bool steal_from_bitmap_to_front(struct btrfs_free_space_ctl *ctl,
struct btrfs_free_space *info,
bool update_stat)
{
struct btrfs_free_space *bitmap;
u64 bitmap_offset;
unsigned long i;
unsigned long j;
unsigned long prev_j;
u64 bytes;
bitmap_offset = offset_to_bitmap(ctl, info->offset);
/* If we're on a boundary, try the previous logical bitmap. */
if (bitmap_offset == info->offset) {
if (info->offset == 0)
return false;
bitmap_offset = offset_to_bitmap(ctl, info->offset - 1);
}
bitmap = tree_search_offset(ctl, bitmap_offset, 1, 0);
if (!bitmap)
return false;
i = offset_to_bit(bitmap->offset, ctl->unit, info->offset) - 1;
j = 0;
prev_j = (unsigned long)-1;
for_each_clear_bit_from(j, bitmap->bitmap, BITS_PER_BITMAP) {
if (j > i)
break;
prev_j = j;
}
if (prev_j == i)
return false;
if (prev_j == (unsigned long)-1)
bytes = (i + 1) * ctl->unit;
else
bytes = (i - prev_j) * ctl->unit;
info->offset -= bytes;
info->bytes += bytes;
/* See try_merge_free_space() comment. */
if (!btrfs_free_space_trimmed(bitmap))
info->trim_state = BTRFS_TRIM_STATE_UNTRIMMED;
bitmap_clear_bits(ctl, bitmap, info->offset, bytes, update_stat);
if (!bitmap->bytes)
free_bitmap(ctl, bitmap);
return true;
}
/*
* We prefer always to allocate from extent entries, both for clustered and
* non-clustered allocation requests. So when attempting to add a new extent
* entry, try to see if there's adjacent free space in bitmap entries, and if
* there is, migrate that space from the bitmaps to the extent.
* Like this we get better chances of satisfying space allocation requests
* because we attempt to satisfy them based on a single cache entry, and never
* on 2 or more entries - even if the entries represent a contiguous free space
* region (e.g. 1 extent entry + 1 bitmap entry starting where the extent entry
* ends).
*/
static void steal_from_bitmap(struct btrfs_free_space_ctl *ctl,
struct btrfs_free_space *info,
bool update_stat)
{
/*
* Only work with disconnected entries, as we can change their offset,
* and must be extent entries.
*/
ASSERT(!info->bitmap);
ASSERT(RB_EMPTY_NODE(&info->offset_index));
if (ctl->total_bitmaps > 0) {
bool stole_end;
bool stole_front = false;
stole_end = steal_from_bitmap_to_end(ctl, info, update_stat);
if (ctl->total_bitmaps > 0)
stole_front = steal_from_bitmap_to_front(ctl, info,
update_stat);
if (stole_end || stole_front)
try_merge_free_space(ctl, info, update_stat);
}
}
int __btrfs_add_free_space(struct btrfs_block_group *block_group,
u64 offset, u64 bytes,
enum btrfs_trim_state trim_state)
{
struct btrfs_fs_info *fs_info = block_group->fs_info;
struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
struct btrfs_free_space *info;
int ret = 0;
u64 filter_bytes = bytes;
ASSERT(!btrfs_is_zoned(fs_info));
info = kmem_cache_zalloc(btrfs_free_space_cachep, GFP_NOFS);
if (!info)
return -ENOMEM;
info->offset = offset;
info->bytes = bytes;
info->trim_state = trim_state;
RB_CLEAR_NODE(&info->offset_index);
RB_CLEAR_NODE(&info->bytes_index);
spin_lock(&ctl->tree_lock);
if (try_merge_free_space(ctl, info, true))
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
*/
ret = insert_into_bitmap(ctl, info);
if (ret < 0) {
goto out;
} else if (ret) {
ret = 0;
goto out;
}
link:
/*
* Only steal free space from adjacent bitmaps if we're sure we're not
* going to add the new free space to existing bitmap entries - because
* that would mean unnecessary work that would be reverted. Therefore
* attempt to steal space from bitmaps if we're adding an extent entry.
*/
steal_from_bitmap(ctl, info, true);
filter_bytes = max(filter_bytes, info->bytes);
ret = link_free_space(ctl, info);
if (ret)
kmem_cache_free(btrfs_free_space_cachep, info);
out:
btrfs_discard_update_discardable(block_group);
spin_unlock(&ctl->tree_lock);
if (ret) {
btrfs_crit(fs_info, "unable to add free space :%d", ret);
ASSERT(ret != -EEXIST);
}
if (trim_state != BTRFS_TRIM_STATE_TRIMMED) {
btrfs_discard_check_filter(block_group, filter_bytes);
btrfs_discard_queue_work(&fs_info->discard_ctl, block_group);
}
return ret;
}
static int __btrfs_add_free_space_zoned(struct btrfs_block_group *block_group,
u64 bytenr, u64 size, bool used)
{
struct btrfs_space_info *sinfo = block_group->space_info;
struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
u64 offset = bytenr - block_group->start;
u64 to_free, to_unusable;
int bg_reclaim_threshold = 0;
bool initial = (size == block_group->length);
u64 reclaimable_unusable;
WARN_ON(!initial && offset + size > block_group->zone_capacity);
if (!initial)
bg_reclaim_threshold = READ_ONCE(sinfo->bg_reclaim_threshold);
spin_lock(&ctl->tree_lock);
if (!used)
to_free = size;
else if (initial)
to_free = block_group->zone_capacity;
else if (offset >= block_group->alloc_offset)
to_free = size;
else if (offset + size <= block_group->alloc_offset)
to_free = 0;
else
to_free = offset + size - block_group->alloc_offset;
to_unusable = size - to_free;
ctl->free_space += to_free;
/*
* If the block group is read-only, we should account freed space into
* bytes_readonly.
*/
if (!block_group->ro)
block_group->zone_unusable += to_unusable;
spin_unlock(&ctl->tree_lock);
if (!used) {
spin_lock(&block_group->lock);
block_group->alloc_offset -= size;
spin_unlock(&block_group->lock);
}
reclaimable_unusable = block_group->zone_unusable -
(block_group->length - block_group->zone_capacity);
/* All the region is now unusable. Mark it as unused and reclaim */
if (block_group->zone_unusable == block_group->length) {
btrfs_mark_bg_unused(block_group);
} else if (bg_reclaim_threshold &&
reclaimable_unusable >=
mult_perc(block_group->zone_capacity, bg_reclaim_threshold)) {
btrfs_mark_bg_to_reclaim(block_group);
}
return 0;
}
int btrfs_add_free_space(struct btrfs_block_group *block_group,
u64 bytenr, u64 size)
{
enum btrfs_trim_state trim_state = BTRFS_TRIM_STATE_UNTRIMMED;
if (btrfs_is_zoned(block_group->fs_info))
return __btrfs_add_free_space_zoned(block_group, bytenr, size,
true);
if (btrfs_test_opt(block_group->fs_info, DISCARD_SYNC))
trim_state = BTRFS_TRIM_STATE_TRIMMED;
return __btrfs_add_free_space(block_group, bytenr, size, trim_state);
}
int btrfs_add_free_space_unused(struct btrfs_block_group *block_group,
u64 bytenr, u64 size)
{
if (btrfs_is_zoned(block_group->fs_info))
return __btrfs_add_free_space_zoned(block_group, bytenr, size,
false);
return btrfs_add_free_space(block_group, bytenr, size);
}
/*
* This is a subtle distinction because when adding free space back in general,
* we want it to be added as untrimmed for async. But in the case where we add
* it on loading of a block group, we want to consider it trimmed.
*/
int btrfs_add_free_space_async_trimmed(struct btrfs_block_group *block_group,
u64 bytenr, u64 size)
{
enum btrfs_trim_state trim_state = BTRFS_TRIM_STATE_UNTRIMMED;
if (btrfs_is_zoned(block_group->fs_info))
return __btrfs_add_free_space_zoned(block_group, bytenr, size,
true);
if (btrfs_test_opt(block_group->fs_info, DISCARD_SYNC) ||
btrfs_test_opt(block_group->fs_info, DISCARD_ASYNC))
trim_state = BTRFS_TRIM_STATE_TRIMMED;
return __btrfs_add_free_space(block_group, bytenr, size, trim_state);
}
int btrfs_remove_free_space(struct btrfs_block_group *block_group,
u64 offset, u64 bytes)
{
struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
struct btrfs_free_space *info;
int ret;
bool re_search = false;
if (btrfs_is_zoned(block_group->fs_info)) {
/*
* This can happen with conventional zones when replaying log.
* Since the allocation info of tree-log nodes are not recorded
* to the extent-tree, calculate_alloc_pointer() failed to
* advance the allocation pointer after last allocated tree log
* node blocks.
*
* This function is called from
* btrfs_pin_extent_for_log_replay() when replaying the log.
* Advance the pointer not to overwrite the tree-log nodes.
*/
if (block_group->start + block_group->alloc_offset <
offset + bytes) {
block_group->alloc_offset =
offset + bytes - block_group->start;
}
return 0;
}
spin_lock(&ctl->tree_lock);
again:
ret = 0;
if (!bytes)
goto out_lock;
info = tree_search_offset(ctl, offset, 0, 0);
if (!info) {
/*
* oops didn't find an extent that matched the space we wanted
* to remove, look for a bitmap instead
*/
info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
1, 0);
if (!info) {
/*
* 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.
*/
WARN_ON(re_search);
goto out_lock;
}
}
re_search = false;
if (!info->bitmap) {
unlink_free_space(ctl, info, true);
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);
}
offset += to_free;
bytes -= to_free;
goto again;
} else {
u64 old_end = info->bytes + info->offset;
info->bytes = offset - info->offset;
ret = link_free_space(ctl, info);
WARN_ON(ret);
if (ret)
goto out_lock;
/* 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),
info->trim_state);
WARN_ON(ret);
goto out;
}
}
ret = remove_from_bitmap(ctl, info, &offset, &bytes);
if (ret == -EAGAIN) {
re_search = true;
goto again;
}
out_lock:
btrfs_discard_update_discardable(block_group);
spin_unlock(&ctl->tree_lock);
out:
return ret;
}
void btrfs_dump_free_space(struct btrfs_block_group *block_group,
u64 bytes)
{
struct btrfs_fs_info *fs_info = block_group->fs_info;
struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
struct btrfs_free_space *info;
struct rb_node *n;
int count = 0;
/*
* Zoned btrfs does not use free space tree and cluster. Just print
* out the free space after the allocation offset.
*/
if (btrfs_is_zoned(fs_info)) {
btrfs_info(fs_info, "free space %llu active %d",
block_group->zone_capacity - block_group->alloc_offset,
test_bit(BLOCK_GROUP_FLAG_ZONE_IS_ACTIVE,
&block_group->runtime_flags));
return;
}
spin_lock(&ctl->tree_lock);
for (n = rb_first(&ctl->free_space_offset); n; n = rb_next(n)) {
info = rb_entry(n, struct btrfs_free_space, offset_index);
if (info->bytes >= bytes && !block_group->ro)
count++;
btrfs_crit(fs_info, "entry offset %llu, bytes %llu, bitmap %s",
info->offset, info->bytes,
(info->bitmap) ? "yes" : "no");
}
spin_unlock(&ctl->tree_lock);
btrfs_info(fs_info, "block group has cluster?: %s",
list_empty(&block_group->cluster_list) ? "no" : "yes");
btrfs_info(fs_info,
"%d free space entries at or bigger than %llu bytes",
count, bytes);
}
void btrfs_init_free_space_ctl(struct btrfs_block_group *block_group,
struct btrfs_free_space_ctl *ctl)
{
struct btrfs_fs_info *fs_info = block_group->fs_info;
spin_lock_init(&ctl->tree_lock);
ctl->unit = fs_info->sectorsize;
ctl->start = block_group->start;
ctl->block_group = block_group;
ctl->op = &free_space_op;
ctl->free_space_bytes = RB_ROOT_CACHED;
INIT_LIST_HEAD(&ctl->trimming_ranges);
mutex_init(&ctl->cache_writeout_mutex);
/*
* 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 = (SZ_32K / 2) / sizeof(struct btrfs_free_space);
}
/*
* 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 void __btrfs_return_cluster_to_free_space(
struct btrfs_block_group *block_group,
struct btrfs_free_cluster *cluster)
{
struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
struct rb_node *node;
lockdep_assert_held(&ctl->tree_lock);
spin_lock(&cluster->lock);
if (cluster->block_group != block_group) {
spin_unlock(&cluster->lock);
return;
}
cluster->block_group = NULL;
cluster->window_start = 0;
list_del_init(&cluster->block_group_list);
node = rb_first(&cluster->root);
while (node) {
struct btrfs_free_space *entry;
entry = rb_entry(node, struct btrfs_free_space, offset_index);
node = rb_next(&entry->offset_index);
rb_erase(&entry->offset_index, &cluster->root);
RB_CLEAR_NODE(&entry->offset_index);
if (!entry->bitmap) {
/* Merging treats extents as if they were new */
if (!btrfs_free_space_trimmed(entry)) {
ctl->discardable_extents[BTRFS_STAT_CURR]--;
ctl->discardable_bytes[BTRFS_STAT_CURR] -=
entry->bytes;
}
try_merge_free_space(ctl, entry, false);
steal_from_bitmap(ctl, entry, false);
/* As we insert directly, update these statistics */
if (!btrfs_free_space_trimmed(entry)) {
ctl->discardable_extents[BTRFS_STAT_CURR]++;
ctl->discardable_bytes[BTRFS_STAT_CURR] +=
entry->bytes;
}
}
tree_insert_offset(ctl, NULL, entry);
rb_add_cached(&entry->bytes_index, &ctl->free_space_bytes,
entry_less);
}
cluster->root = RB_ROOT;
spin_unlock(&cluster->lock);
btrfs_put_block_group(block_group);
}
void btrfs_remove_free_space_cache(struct btrfs_block_group *block_group)
{
struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
struct btrfs_free_cluster *cluster;
struct list_head *head;
spin_lock(&ctl->tree_lock);
while ((head = block_group->cluster_list.next) !=
&block_group->cluster_list) {
cluster = list_entry(head, struct btrfs_free_cluster,
block_group_list);
WARN_ON(cluster->block_group != block_group);
__btrfs_return_cluster_to_free_space(block_group, cluster);
cond_resched_lock(&ctl->tree_lock);
}
__btrfs_remove_free_space_cache(ctl);
btrfs_discard_update_discardable(block_group);
spin_unlock(&ctl->tree_lock);
}
/*
* Walk @block_group's free space rb_tree to determine if everything is trimmed.
*/
bool btrfs_is_free_space_trimmed(struct btrfs_block_group *block_group)
{
struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
struct btrfs_free_space *info;
struct rb_node *node;
bool ret = true;
spin_lock(&ctl->tree_lock);
node = rb_first(&ctl->free_space_offset);
while (node) {
info = rb_entry(node, struct btrfs_free_space, offset_index);
if (!btrfs_free_space_trimmed(info)) {
ret = false;
break;
}
node = rb_next(node);
}
spin_unlock(&ctl->tree_lock);
return ret;
}
u64 btrfs_find_space_for_alloc(struct btrfs_block_group *block_group,
u64 offset, u64 bytes, u64 empty_size,
u64 *max_extent_size)
{
struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
struct btrfs_discard_ctl *discard_ctl =
&block_group->fs_info->discard_ctl;
struct btrfs_free_space *entry = NULL;
u64 bytes_search = bytes + empty_size;
u64 ret = 0;
u64 align_gap = 0;
u64 align_gap_len = 0;
enum btrfs_trim_state align_gap_trim_state = BTRFS_TRIM_STATE_UNTRIMMED;
bool use_bytes_index = (offset == block_group->start);
ASSERT(!btrfs_is_zoned(block_group->fs_info));
spin_lock(&ctl->tree_lock);
entry = find_free_space(ctl, &offset, &bytes_search,
block_group->full_stripe_len, max_extent_size,
use_bytes_index);
if (!entry)
goto out;
ret = offset;
if (entry->bitmap) {
bitmap_clear_bits(ctl, entry, offset, bytes, true);
if (!btrfs_free_space_trimmed(entry))
atomic64_add(bytes, &discard_ctl->discard_bytes_saved);
if (!entry->bytes)
free_bitmap(ctl, entry);
} else {
unlink_free_space(ctl, entry, true);
align_gap_len = offset - entry->offset;
align_gap = entry->offset;
align_gap_trim_state = entry->trim_state;
if (!btrfs_free_space_trimmed(entry))
atomic64_add(bytes, &discard_ctl->discard_bytes_saved);
entry->offset = offset + bytes;
WARN_ON(entry->bytes < bytes + align_gap_len);
entry->bytes -= bytes + align_gap_len;
if (!entry->bytes)
kmem_cache_free(btrfs_free_space_cachep, entry);
else
link_free_space(ctl, entry);
}
out:
btrfs_discard_update_discardable(block_group);
spin_unlock(&ctl->tree_lock);
if (align_gap_len)
__btrfs_add_free_space(block_group, align_gap, align_gap_len,
align_gap_trim_state);
return ret;
}
/*
* 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.
*/
void btrfs_return_cluster_to_free_space(
struct btrfs_block_group *block_group,
struct btrfs_free_cluster *cluster)
{
struct btrfs_free_space_ctl *ctl;
/* 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;
}
} else if (cluster->block_group != block_group) {
/* someone else has already freed it don't redo their work */
spin_unlock(&cluster->lock);
return;
}
btrfs_get_block_group(block_group);
spin_unlock(&cluster->lock);
ctl = block_group->free_space_ctl;
/* now return any extents the cluster had on it */
spin_lock(&ctl->tree_lock);
__btrfs_return_cluster_to_free_space(block_group, cluster);
spin_unlock(&ctl->tree_lock);
btrfs_discard_queue_work(&block_group->fs_info->discard_ctl, block_group);
/* finally drop our ref */
btrfs_put_block_group(block_group);
}
static u64 btrfs_alloc_from_bitmap(struct btrfs_block_group *block_group,
struct btrfs_free_cluster *cluster,
struct btrfs_free_space *entry,
u64 bytes, u64 min_start,
u64 *max_extent_size)
{
struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
int err;
u64 search_start = cluster->window_start;
u64 search_bytes = bytes;
u64 ret = 0;
search_start = min_start;
search_bytes = bytes;
err = search_bitmap(ctl, entry, &search_start, &search_bytes, true);
if (err) {
*max_extent_size = max(get_max_extent_size(entry),
*max_extent_size);
return 0;
}
ret = search_start;
bitmap_clear_bits(ctl, entry, ret, bytes, false);
return ret;
}
/*
* 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 *block_group,
struct btrfs_free_cluster *cluster, u64 bytes,
u64 min_start, u64 *max_extent_size)
{
struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
struct btrfs_discard_ctl *discard_ctl =
&block_group->fs_info->discard_ctl;
struct btrfs_free_space *entry = NULL;
struct rb_node *node;
u64 ret = 0;
ASSERT(!btrfs_is_zoned(block_group->fs_info));
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);
while (1) {
if (entry->bytes < bytes)
*max_extent_size = max(get_max_extent_size(entry),
*max_extent_size);
if (entry->bytes < bytes ||
(!entry->bitmap && entry->offset < min_start)) {
node = rb_next(&entry->offset_index);
if (!node)
break;
entry = rb_entry(node, struct btrfs_free_space,
offset_index);
continue;
}
if (entry->bitmap) {
ret = btrfs_alloc_from_bitmap(block_group,
cluster, entry, bytes,
cluster->window_start,
max_extent_size);
if (ret == 0) {
node = rb_next(&entry->offset_index);
if (!node)
break;
entry = rb_entry(node, struct btrfs_free_space,
offset_index);
continue;
}
cluster->window_start += bytes;
} else {
ret = entry->offset;
entry->offset += bytes;
entry->bytes -= bytes;
}
break;
}
out:
spin_unlock(&cluster->lock);
if (!ret)
return 0;
spin_lock(&ctl->tree_lock);
if (!btrfs_free_space_trimmed(entry))
atomic64_add(bytes, &discard_ctl->discard_bytes_saved);
ctl->free_space -= bytes;
if (!entry->bitmap && !btrfs_free_space_trimmed(entry))
ctl->discardable_bytes[BTRFS_STAT_CURR] -= bytes;
spin_lock(&cluster->lock);
if (entry->bytes == 0) {
rb_erase(&entry->offset_index, &cluster->root);
ctl->free_extents--;
if (entry->bitmap) {
kmem_cache_free(btrfs_free_space_bitmap_cachep,
entry->bitmap);
ctl->total_bitmaps--;
recalculate_thresholds(ctl);
} else if (!btrfs_free_space_trimmed(entry)) {
ctl->discardable_extents[BTRFS_STAT_CURR]--;
}
kmem_cache_free(btrfs_free_space_cachep, entry);
}
spin_unlock(&cluster->lock);
spin_unlock(&ctl->tree_lock);
return ret;
}
static int btrfs_bitmap_cluster(struct btrfs_block_group *block_group,
struct btrfs_free_space *entry,
struct btrfs_free_cluster *cluster,
u64 offset, u64 bytes,
u64 cont1_bytes, u64 min_bytes)
{
struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
unsigned long next_zero;
unsigned long i;
unsigned long want_bits;
unsigned long min_bits;
unsigned long found_bits;
unsigned long max_bits = 0;
unsigned long start = 0;
unsigned long total_found = 0;
int ret;
lockdep_assert_held(&ctl->tree_lock);
i = offset_to_bit(entry->offset, ctl->unit,
max_t(u64, offset, entry->offset));
want_bits = bytes_to_bits(bytes, ctl->unit);
min_bits = bytes_to_bits(min_bytes, ctl->unit);
/*
* Don't bother looking for a cluster in this bitmap if it's heavily
* fragmented.
*/
if (entry->max_extent_size &&
entry->max_extent_size < cont1_bytes)
return -ENOSPC;
again:
found_bits = 0;
for_each_set_bit_from(i, entry->bitmap, BITS_PER_BITMAP) {
next_zero = find_next_zero_bit(entry->bitmap,
BITS_PER_BITMAP, i);
if (next_zero - i >= min_bits) {
found_bits = next_zero - i;
if (found_bits > max_bits)
max_bits = found_bits;
break;
}
if (next_zero - i > max_bits)
max_bits = next_zero - i;
i = next_zero;
}
if (!found_bits) {
entry->max_extent_size = (u64)max_bits * ctl->unit;
return -ENOSPC;
}
if (!total_found) {
start = i;
cluster->max_size = 0;
}
total_found += found_bits;
if (cluster->max_size < found_bits * ctl->unit)
cluster->max_size = found_bits * ctl->unit;
if (total_found < want_bits || cluster->max_size < cont1_bytes) {
i = next_zero + 1;
goto again;
}
cluster->window_start = start * ctl->unit + entry->offset;
rb_erase(&entry->offset_index, &ctl->free_space_offset);
rb_erase_cached(&entry->bytes_index, &ctl->free_space_bytes);
/*
* We need to know if we're currently on the normal space index when we
* manipulate the bitmap so that we know we need to remove and re-insert
* it into the space_index tree. Clear the bytes_index node here so the
* bitmap manipulation helpers know not to mess with the space_index
* until this bitmap entry is added back into the normal cache.
*/
RB_CLEAR_NODE(&entry->bytes_index);
ret = tree_insert_offset(ctl, cluster, entry);
ASSERT(!ret); /* -EEXIST; Logic error */
trace_btrfs_setup_cluster(block_group, cluster,
total_found * ctl->unit, 1);
return 0;
}
/*
* This searches the block group for just extents to fill the cluster with.
* 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.
*/
static noinline int
setup_cluster_no_bitmap(struct btrfs_block_group *block_group,
struct btrfs_free_cluster *cluster,
struct list_head *bitmaps, u64 offset, u64 bytes,
u64 cont1_bytes, u64 min_bytes)
{
struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
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;
u64 total_size = 0;
lockdep_assert_held(&ctl->tree_lock);
entry = tree_search_offset(ctl, offset, 0, 1);
if (!entry)
return -ENOSPC;
/*
* We don't want bitmaps, so just move along until we find a normal
* extent entry.
*/
while (entry->bitmap || entry->bytes < min_bytes) {
if (entry->bitmap && list_empty(&entry->list))
list_add_tail(&entry->list, bitmaps);
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;
for (node = rb_next(&entry->offset_index); node;
node = rb_next(&entry->offset_index)) {
entry = rb_entry(node, struct btrfs_free_space, offset_index);
if (entry->bitmap) {
if (list_empty(&entry->list))
list_add_tail(&entry->list, bitmaps);
continue;
}
if (entry->bytes < min_bytes)
continue;
last = entry;
window_free += entry->bytes;
if (entry->bytes > max_extent)
max_extent = entry->bytes;
}
if (window_free < bytes || max_extent < cont1_bytes)
return -ENOSPC;
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);
if (entry->bitmap || entry->bytes < min_bytes)
continue;
rb_erase(&entry->offset_index, &ctl->free_space_offset);
rb_erase_cached(&entry->bytes_index, &ctl->free_space_bytes);
ret = tree_insert_offset(ctl, cluster, entry);
total_size += entry->bytes;
ASSERT(!ret); /* -EEXIST; Logic error */
} while (node && entry != last);
cluster->max_size = max_extent;
trace_btrfs_setup_cluster(block_group, cluster, total_size, 0);
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.
*/
static noinline int
setup_cluster_bitmap(struct btrfs_block_group *block_group,
struct btrfs_free_cluster *cluster,
struct list_head *bitmaps, u64 offset, u64 bytes,
u64 cont1_bytes, u64 min_bytes)
{
struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
struct btrfs_free_space *entry = NULL;
int ret = -ENOSPC;
u64 bitmap_offset = offset_to_bitmap(ctl, offset);
if (ctl->total_bitmaps == 0)
return -ENOSPC;
/*
* The bitmap that covers offset won't be in the list unless offset
* is just its start offset.
*/
if (!list_empty(bitmaps))
entry = list_first_entry(bitmaps, struct btrfs_free_space, list);
if (!entry || entry->offset != bitmap_offset) {
entry = tree_search_offset(ctl, bitmap_offset, 1, 0);
if (entry && list_empty(&entry->list))
list_add(&entry->list, bitmaps);
}
list_for_each_entry(entry, bitmaps, list) {
if (entry->bytes < bytes)
continue;
ret = btrfs_bitmap_cluster(block_group, entry, cluster, offset,
bytes, cont1_bytes, min_bytes);
if (!ret)
return 0;
}
/*
* The bitmaps list has all the bitmaps that record free space
* starting after offset, so no more search is required.
*/
return -ENOSPC;
}
/*
* here we try to find a cluster of blocks in a block group. The goal
* is to find at least bytes+empty_size.
* We might not find them all in one contiguous area.
*
* returns zero and sets up cluster if things worked out, otherwise
* it returns -enospc
*/
int btrfs_find_space_cluster(struct btrfs_block_group *block_group,
struct btrfs_free_cluster *cluster,
u64 offset, u64 bytes, u64 empty_size)
{
struct btrfs_fs_info *fs_info = block_group->fs_info;
struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
struct btrfs_free_space *entry, *tmp;
LIST_HEAD(bitmaps);
u64 min_bytes;
u64 cont1_bytes;
int ret;
/*
* 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.
*/
if (btrfs_test_opt(fs_info, SSD_SPREAD)) {
cont1_bytes = bytes + empty_size;
min_bytes = cont1_bytes;
} else if (block_group->flags & BTRFS_BLOCK_GROUP_METADATA) {
cont1_bytes = bytes;
min_bytes = fs_info->sectorsize;
} else {
cont1_bytes = max(bytes, (bytes + empty_size) >> 2);
min_bytes = fs_info->sectorsize;
}
spin_lock(&ctl->tree_lock);
/*
* 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.
*/
if (ctl->free_space < bytes) {
spin_unlock(&ctl->tree_lock);
return -ENOSPC;
}
spin_lock(&cluster->lock);
/* someone already found a cluster, hooray */
if (cluster->block_group) {
ret = 0;
goto out;
}
trace_btrfs_find_cluster(block_group, offset, bytes, empty_size,
min_bytes);
ret = setup_cluster_no_bitmap(block_group, cluster, &bitmaps, offset,
bytes + empty_size,
cont1_bytes, min_bytes);
if (ret)
ret = setup_cluster_bitmap(block_group, cluster, &bitmaps,
offset, bytes + empty_size,
cont1_bytes, min_bytes);
/* Clear our temporary list */
list_for_each_entry_safe(entry, tmp, &bitmaps, list)
list_del_init(&entry->list);
if (!ret) {
btrfs_get_block_group(block_group);
list_add_tail(&cluster->block_group_list,
&block_group->cluster_list);
cluster->block_group = block_group;
} else {
trace_btrfs_failed_cluster_setup(block_group);
}
out:
spin_unlock(&cluster->lock);
spin_unlock(&ctl->tree_lock);
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);
cluster->root = RB_ROOT;
cluster->max_size = 0;
cluster->fragmented = false;
INIT_LIST_HEAD(&cluster->block_group_list);
cluster->block_group = NULL;
}
static int do_trimming(struct btrfs_block_group *block_group,
u64 *total_trimmed, u64 start, u64 bytes,
u64 reserved_start, u64 reserved_bytes,
enum btrfs_trim_state reserved_trim_state,
struct btrfs_trim_range *trim_entry)
{
struct btrfs_space_info *space_info = block_group->space_info;
struct btrfs_fs_info *fs_info = block_group->fs_info;
struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
int ret;
int update = 0;
const u64 end = start + bytes;
const u64 reserved_end = reserved_start + reserved_bytes;
enum btrfs_trim_state trim_state = BTRFS_TRIM_STATE_UNTRIMMED;
u64 trimmed = 0;
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_discard_extent(fs_info, start, bytes, &trimmed);
if (!ret) {
*total_trimmed += trimmed;
trim_state = BTRFS_TRIM_STATE_TRIMMED;
}
mutex_lock(&ctl->cache_writeout_mutex);
if (reserved_start < start)
__btrfs_add_free_space(block_group, reserved_start,
start - reserved_start,
reserved_trim_state);
if (end < reserved_end)
__btrfs_add_free_space(block_group, end, reserved_end - end,
reserved_trim_state);
__btrfs_add_free_space(block_group, start, bytes, trim_state);
list_del(&trim_entry->list);
mutex_unlock(&ctl->cache_writeout_mutex);
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(&block_group->lock);
spin_unlock(&space_info->lock);
}
return ret;
}
/*
* If @async is set, then we will trim 1 region and return.
*/
static int trim_no_bitmap(struct btrfs_block_group *block_group,
u64 *total_trimmed, u64 start, u64 end, u64 minlen,
bool async)
{
struct btrfs_discard_ctl *discard_ctl =
&block_group->fs_info->discard_ctl;
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;
enum btrfs_trim_state extent_trim_state;
u64 bytes;
const u64 max_discard_size = READ_ONCE(discard_ctl->max_discard_size);
while (start < end) {
struct btrfs_trim_range trim_entry;
mutex_lock(&ctl->cache_writeout_mutex);
spin_lock(&ctl->tree_lock);
if (ctl->free_space < minlen)
goto out_unlock;
entry = tree_search_offset(ctl, start, 0, 1);
if (!entry)
goto out_unlock;
/* Skip bitmaps and if async, already trimmed entries */
while (entry->bitmap ||
(async && btrfs_free_space_trimmed(entry))) {
node = rb_next(&entry->offset_index);
if (!node)
goto out_unlock;
entry = rb_entry(node, struct btrfs_free_space,
offset_index);
}
if (entry->offset >= end)
goto out_unlock;
extent_start = entry->offset;
extent_bytes = entry->bytes;
extent_trim_state = entry->trim_state;
if (async) {
start = entry->offset;
bytes = entry->bytes;
if (bytes < minlen) {
spin_unlock(&ctl->tree_lock);
mutex_unlock(&ctl->cache_writeout_mutex);
goto next;
}
unlink_free_space(ctl, entry, true);
/*
* Let bytes = BTRFS_MAX_DISCARD_SIZE + X.
* If X < BTRFS_ASYNC_DISCARD_MIN_FILTER, we won't trim
* X when we come back around. So trim it now.
*/
if (max_discard_size &&
bytes >= (max_discard_size +
BTRFS_ASYNC_DISCARD_MIN_FILTER)) {
bytes = max_discard_size;
extent_bytes = max_discard_size;
entry->offset += max_discard_size;
entry->bytes -= max_discard_size;
link_free_space(ctl, entry);
} else {
kmem_cache_free(btrfs_free_space_cachep, entry);
}
} else {
start = max(start, extent_start);
bytes = min(extent_start + extent_bytes, end) - start;
if (bytes < minlen) {
spin_unlock(&ctl->tree_lock);
mutex_unlock(&ctl->cache_writeout_mutex);
goto next;
}
unlink_free_space(ctl, entry, true);
kmem_cache_free(btrfs_free_space_cachep, entry);
}
spin_unlock(&ctl->tree_lock);
trim_entry.start = extent_start;
trim_entry.bytes = extent_bytes;
list_add_tail(&trim_entry.list, &ctl->trimming_ranges);
mutex_unlock(&ctl->cache_writeout_mutex);
ret = do_trimming(block_group, total_trimmed, start, bytes,
extent_start, extent_bytes, extent_trim_state,
&trim_entry);
if (ret) {
block_group->discard_cursor = start + bytes;
break;
}
next:
start += bytes;
block_group->discard_cursor = start;
if (async && *total_trimmed)
break;
if (fatal_signal_pending(current)) {
ret = -ERESTARTSYS;
break;
}
cond_resched();
}
return ret;
out_unlock:
block_group->discard_cursor = btrfs_block_group_end(block_group);
spin_unlock(&ctl->tree_lock);
mutex_unlock(&ctl->cache_writeout_mutex);
return ret;
}
/*
* If we break out of trimming a bitmap prematurely, we should reset the
* trimming bit. In a rather contrieved case, it's possible to race here so
* reset the state to BTRFS_TRIM_STATE_UNTRIMMED.
*
* start = start of bitmap
* end = near end of bitmap
*
* Thread 1: Thread 2:
* trim_bitmaps(start)
* trim_bitmaps(end)
* end_trimming_bitmap()
* reset_trimming_bitmap()
*/
static void reset_trimming_bitmap(struct btrfs_free_space_ctl *ctl, u64 offset)
{
struct btrfs_free_space *entry;
spin_lock(&ctl->tree_lock);
entry = tree_search_offset(ctl, offset, 1, 0);
if (entry) {
if (btrfs_free_space_trimmed(entry)) {
ctl->discardable_extents[BTRFS_STAT_CURR] +=
entry->bitmap_extents;
ctl->discardable_bytes[BTRFS_STAT_CURR] += entry->bytes;
}
entry->trim_state = BTRFS_TRIM_STATE_UNTRIMMED;
}
spin_unlock(&ctl->tree_lock);
}
static void end_trimming_bitmap(struct btrfs_free_space_ctl *ctl,
struct btrfs_free_space *entry)
{
if (btrfs_free_space_trimming_bitmap(entry)) {
entry->trim_state = BTRFS_TRIM_STATE_TRIMMED;
ctl->discardable_extents[BTRFS_STAT_CURR] -=
entry->bitmap_extents;
ctl->discardable_bytes[BTRFS_STAT_CURR] -= entry->bytes;
}
}
/*
* If @async is set, then we will trim 1 region and return.
*/
static int trim_bitmaps(struct btrfs_block_group *block_group,
u64 *total_trimmed, u64 start, u64 end, u64 minlen,
u64 maxlen, bool async)
{
struct btrfs_discard_ctl *discard_ctl =
&block_group->fs_info->discard_ctl;
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);
const u64 max_discard_size = READ_ONCE(discard_ctl->max_discard_size);
while (offset < end) {
bool next_bitmap = false;
struct btrfs_trim_range trim_entry;
mutex_lock(&ctl->cache_writeout_mutex);
spin_lock(&ctl->tree_lock);
if (ctl->free_space < minlen) {
block_group->discard_cursor =
btrfs_block_group_end(block_group);
spin_unlock(&ctl->tree_lock);
mutex_unlock(&ctl->cache_writeout_mutex);
break;
}
entry = tree_search_offset(ctl, offset, 1, 0);
/*
* Bitmaps are marked trimmed lossily now to prevent constant
* discarding of the same bitmap (the reason why we are bound
* by the filters). So, retrim the block group bitmaps when we
* are preparing to punt to the unused_bgs list. This uses
* @minlen to determine if we are in BTRFS_DISCARD_INDEX_UNUSED
* which is the only discard index which sets minlen to 0.
*/
if (!entry || (async && minlen && start == offset &&
btrfs_free_space_trimmed(entry))) {
spin_unlock(&ctl->tree_lock);
mutex_unlock(&ctl->cache_writeout_mutex);
next_bitmap = true;
goto next;
}
/*
* Async discard bitmap trimming begins at by setting the start
* to be key.objectid and the offset_to_bitmap() aligns to the
* start of the bitmap. This lets us know we are fully
* scanning the bitmap rather than only some portion of it.
*/
if (start == offset)
entry->trim_state = BTRFS_TRIM_STATE_TRIMMING;
bytes = minlen;
ret2 = search_bitmap(ctl, entry, &start, &bytes, false);
if (ret2 || start >= end) {
/*
* We lossily consider a bitmap trimmed if we only skip
* over regions <= BTRFS_ASYNC_DISCARD_MIN_FILTER.
*/
if (ret2 && minlen <= BTRFS_ASYNC_DISCARD_MIN_FILTER)
end_trimming_bitmap(ctl, entry);
else
entry->trim_state = BTRFS_TRIM_STATE_UNTRIMMED;
spin_unlock(&ctl->tree_lock);
mutex_unlock(&ctl->cache_writeout_mutex);
next_bitmap = true;
goto next;
}
/*
* We already trimmed a region, but are using the locking above
* to reset the trim_state.
*/
if (async && *total_trimmed) {
spin_unlock(&ctl->tree_lock);
mutex_unlock(&ctl->cache_writeout_mutex);
goto out;
}
bytes = min(bytes, end - start);
if (bytes < minlen || (async && maxlen && bytes > maxlen)) {
spin_unlock(&ctl->tree_lock);
mutex_unlock(&ctl->cache_writeout_mutex);
goto next;
}
/*
* Let bytes = BTRFS_MAX_DISCARD_SIZE + X.
* If X < @minlen, we won't trim X when we come back around.
* So trim it now. We differ here from trimming extents as we
* don't keep individual state per bit.
*/
if (async &&
max_discard_size &&
bytes > (max_discard_size + minlen))
bytes = max_discard_size;
bitmap_clear_bits(ctl, entry, start, bytes, true);
if (entry->bytes == 0)
free_bitmap(ctl, entry);
spin_unlock(&ctl->tree_lock);
trim_entry.start = start;
trim_entry.bytes = bytes;
list_add_tail(&trim_entry.list, &ctl->trimming_ranges);
mutex_unlock(&ctl->cache_writeout_mutex);
ret = do_trimming(block_group, total_trimmed, start, bytes,
start, bytes, 0, &trim_entry);
if (ret) {
reset_trimming_bitmap(ctl, offset);
block_group->discard_cursor =
btrfs_block_group_end(block_group);
break;
}
next:
if (next_bitmap) {
offset += BITS_PER_BITMAP * ctl->unit;
start = offset;
} else {
start += bytes;
}
block_group->discard_cursor = start;
if (fatal_signal_pending(current)) {
if (start != offset)
reset_trimming_bitmap(ctl, offset);
ret = -ERESTARTSYS;
break;
}
cond_resched();
}
if (offset >= end)
block_group->discard_cursor = end;
out:
return ret;
}
int btrfs_trim_block_group(struct btrfs_block_group *block_group,
u64 *trimmed, u64 start, u64 end, u64 minlen)
{
struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
int ret;
u64 rem = 0;
ASSERT(!btrfs_is_zoned(block_group->fs_info));
*trimmed = 0;
spin_lock(&block_group->lock);
if (test_bit(BLOCK_GROUP_FLAG_REMOVED, &block_group->runtime_flags)) {
spin_unlock(&block_group->lock);
return 0;
}
btrfs_freeze_block_group(block_group);
spin_unlock(&block_group->lock);
ret = trim_no_bitmap(block_group, trimmed, start, end, minlen, false);
if (ret)
goto out;
ret = trim_bitmaps(block_group, trimmed, start, end, minlen, 0, false);
div64_u64_rem(end, BITS_PER_BITMAP * ctl->unit, &rem);
/* If we ended in the middle of a bitmap, reset the trimming flag */
if (rem)
reset_trimming_bitmap(ctl, offset_to_bitmap(ctl, end));
out:
btrfs_unfreeze_block_group(block_group);
return ret;
}
int btrfs_trim_block_group_extents(struct btrfs_block_group *block_group,
u64 *trimmed, u64 start, u64 end, u64 minlen,
bool async)
{
int ret;
*trimmed = 0;
spin_lock(&block_group->lock);
if (test_bit(BLOCK_GROUP_FLAG_REMOVED, &block_group->runtime_flags)) {
spin_unlock(&block_group->lock);
return 0;
}
btrfs_freeze_block_group(block_group);
spin_unlock(&block_group->lock);
ret = trim_no_bitmap(block_group, trimmed, start, end, minlen, async);
btrfs_unfreeze_block_group(block_group);
return ret;
}
int btrfs_trim_block_group_bitmaps(struct btrfs_block_group *block_group,
u64 *trimmed, u64 start, u64 end, u64 minlen,
u64 maxlen, bool async)
{
int ret;
*trimmed = 0;
spin_lock(&block_group->lock);
if (test_bit(BLOCK_GROUP_FLAG_REMOVED, &block_group->runtime_flags)) {
spin_unlock(&block_group->lock);
return 0;
}
btrfs_freeze_block_group(block_group);
spin_unlock(&block_group->lock);
ret = trim_bitmaps(block_group, trimmed, start, end, minlen, maxlen,
async);
btrfs_unfreeze_block_group(block_group);
return ret;
}
bool btrfs_free_space_cache_v1_active(struct btrfs_fs_info *fs_info)
{
return btrfs_super_cache_generation(fs_info->super_copy);
}
static int cleanup_free_space_cache_v1(struct btrfs_fs_info *fs_info,
struct btrfs_trans_handle *trans)
{
struct btrfs_block_group *block_group;
struct rb_node *node;
int ret = 0;
btrfs_info(fs_info, "cleaning free space cache v1");
node = rb_first_cached(&fs_info->block_group_cache_tree);
while (node) {
block_group = rb_entry(node, struct btrfs_block_group, cache_node);
ret = btrfs_remove_free_space_inode(trans, NULL, block_group);
if (ret)
goto out;
node = rb_next(node);
}
out:
return ret;
}
int btrfs_set_free_space_cache_v1_active(struct btrfs_fs_info *fs_info, bool active)
{
struct btrfs_trans_handle *trans;
int ret;
/*
* update_super_roots will appropriately set or unset
* super_copy->cache_generation based on SPACE_CACHE and
* BTRFS_FS_CLEANUP_SPACE_CACHE_V1. For this reason, we need a
* transaction commit whether we are enabling space cache v1 and don't
* have any other work to do, or are disabling it and removing free
* space inodes.
*/
trans = btrfs_start_transaction(fs_info->tree_root, 0);
if (IS_ERR(trans))
return PTR_ERR(trans);
if (!active) {
set_bit(BTRFS_FS_CLEANUP_SPACE_CACHE_V1, &fs_info->flags);
ret = cleanup_free_space_cache_v1(fs_info, trans);
if (ret) {
btrfs_abort_transaction(trans, ret);
btrfs_end_transaction(trans);
goto out;
}
}
ret = btrfs_commit_transaction(trans);
out:
clear_bit(BTRFS_FS_CLEANUP_SPACE_CACHE_V1, &fs_info->flags);
return ret;
}
int __init btrfs_free_space_init(void)
{
btrfs_free_space_cachep = kmem_cache_create("btrfs_free_space",
sizeof(struct btrfs_free_space), 0,
SLAB_MEM_SPREAD, NULL);
if (!btrfs_free_space_cachep)
return -ENOMEM;
btrfs_free_space_bitmap_cachep = kmem_cache_create("btrfs_free_space_bitmap",
PAGE_SIZE, PAGE_SIZE,
SLAB_MEM_SPREAD, NULL);
if (!btrfs_free_space_bitmap_cachep) {
kmem_cache_destroy(btrfs_free_space_cachep);
return -ENOMEM;
}
return 0;
}
void __cold btrfs_free_space_exit(void)
{
kmem_cache_destroy(btrfs_free_space_cachep);
kmem_cache_destroy(btrfs_free_space_bitmap_cachep);
}
#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
/*
* 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,
u64 offset, u64 bytes, bool bitmap)
{
struct btrfs_free_space_ctl *ctl = cache->free_space_ctl;
struct btrfs_free_space *info = NULL, *bitmap_info;
void *map = NULL;
enum btrfs_trim_state trim_state = BTRFS_TRIM_STATE_TRIMMED;
u64 bytes_added;
int ret;
again:
if (!info) {
info = kmem_cache_zalloc(btrfs_free_space_cachep, GFP_NOFS);
if (!info)
return -ENOMEM;
}
if (!bitmap) {
spin_lock(&ctl->tree_lock);
info->offset = offset;
info->bytes = bytes;
info->max_extent_size = 0;
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 = kmem_cache_zalloc(btrfs_free_space_bitmap_cachep, 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;
info = NULL;
}
bytes_added = add_bytes_to_bitmap(ctl, bitmap_info, offset, bytes,
trim_state);
bytes -= bytes_added;
offset += bytes_added;
spin_unlock(&ctl->tree_lock);
if (bytes)
goto again;
if (info)
kmem_cache_free(btrfs_free_space_cachep, info);
if (map)
kmem_cache_free(btrfs_free_space_bitmap_cachep, map);
return 0;
}
/*
* 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.
*/
int test_check_exists(struct btrfs_block_group *cache,
u64 offset, u64 bytes)
{
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, false);
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(&tmp->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(&tmp->offset_index);
continue;
}
info = tmp;
goto have_info;
}
ret = 0;
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;
}
#endif /* CONFIG_BTRFS_FS_RUN_SANITY_TESTS */
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