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linux/fs/btrfs/free-space-cache.c
Qu Wenruo e820dbeb6a btrfs: convert btrfs_buffered_write() to use folios 
The buffered write path is still heavily utilizing the page interface.
Since we have converted it to do a page-by-page copying, it's much easier
to convert all involved functions to folio interface, this involves:

- btrfs_copy_from_user()
- btrfs_drop_folio()
- prepare_uptodate_page()
- prepare_one_page()
- lock_and_cleanup_extent_if_need()
- btrfs_dirty_page()

All function are changed to accept a folio parameter, and if the word
"page" is in the function name, change that to "folio" too.

The function btrfs_dirty_page() is exported for v1 space cache, convert
v1 cache call site to convert its page to folio for the new interface.

And there is a small enhancement for prepare_one_folio(), instead of
manually waiting for the page writeback, let __filemap_get_folio() to
handle that by using FGP_WRITEBEGIN, which implies
(FGP_LOCK | FGP_WRITE | FGP_CREAT | FGP_STABLE).

Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-11-11 14:34:19 +01:00

4345 lines
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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 <linux/string_choices.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 "space-info.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_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(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->vfs_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 = BTRFS_I(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 = inode_to_fs_info(inode);
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_bitmap_cachep, e->bitmap);
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(BTRFS_I(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;
int i_size;
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. */
i_size = i_size_read(inode);
for (int i = 0; i < round_up(i_size, PAGE_SIZE) / PAGE_SIZE; i++) {
u64 dirty_start = i * PAGE_SIZE;
u64 dirty_len = min_t(u64, dirty_start + PAGE_SIZE, i_size) - dirty_start;
ret = btrfs_dirty_folio(BTRFS_I(inode), page_folio(io_ctl->pages[i]),
dirty_start, dirty_len, &cached_state, false);
if (ret < 0)
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(BTRFS_I(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 btrfs_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);
btrfs_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);
}
}
static 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;
u64 reclaimable_unusable;
spin_lock(&block_group->lock);
initial = ((size == block_group->length) && (block_group->alloc_offset == 0));
WARN_ON(!initial && offset + size > block_group->zone_capacity);
if (!initial)
bg_reclaim_threshold = READ_ONCE(sinfo->bg_reclaim_threshold);
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;
spin_lock(&ctl->tree_lock);
ctl->free_space += to_free;
spin_unlock(&ctl->tree_lock);
/*
* 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;
WARN_ON(block_group->zone_unusable > block_group->length);
}
if (!used) {
block_group->alloc_offset -= size;
}
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);
}
spin_unlock(&block_group->lock);
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, str_yes_no(info->bitmap));
}
spin_unlock(&ctl->tree_lock);
btrfs_info(fs_info, "block group has cluster?: %s",
str_no_yes(list_empty(&block_group->cluster_list)));
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 (btrfs_trim_interrupted()) {
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 (btrfs_trim_interrupted()) {
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(btrfs_free_space, 0);
if (!btrfs_free_space_cachep)
return -ENOMEM;
btrfs_free_space_bitmap_cachep = kmem_cache_create("btrfs_free_space_bitmap",
PAGE_SIZE, PAGE_SIZE,
0, 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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