https://github.com/torvalds/linux
Tip revision: af8c34ce6ae32addda3788d54a7e340cad22516b authored by Linus Torvalds on 05 June 2016, 21:31:26 UTC
Linux 4.7-rc2
Linux 4.7-rc2
Tip revision: af8c34c
extent_cache.c
/*
* f2fs extent cache support
*
* Copyright (c) 2015 Motorola Mobility
* Copyright (c) 2015 Samsung Electronics
* Authors: Jaegeuk Kim <jaegeuk@kernel.org>
* Chao Yu <chao2.yu@samsung.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/fs.h>
#include <linux/f2fs_fs.h>
#include "f2fs.h"
#include "node.h"
#include <trace/events/f2fs.h>
static struct kmem_cache *extent_tree_slab;
static struct kmem_cache *extent_node_slab;
static struct extent_node *__attach_extent_node(struct f2fs_sb_info *sbi,
struct extent_tree *et, struct extent_info *ei,
struct rb_node *parent, struct rb_node **p)
{
struct extent_node *en;
en = kmem_cache_alloc(extent_node_slab, GFP_ATOMIC);
if (!en)
return NULL;
en->ei = *ei;
INIT_LIST_HEAD(&en->list);
en->et = et;
rb_link_node(&en->rb_node, parent, p);
rb_insert_color(&en->rb_node, &et->root);
atomic_inc(&et->node_cnt);
atomic_inc(&sbi->total_ext_node);
return en;
}
static void __detach_extent_node(struct f2fs_sb_info *sbi,
struct extent_tree *et, struct extent_node *en)
{
rb_erase(&en->rb_node, &et->root);
atomic_dec(&et->node_cnt);
atomic_dec(&sbi->total_ext_node);
if (et->cached_en == en)
et->cached_en = NULL;
kmem_cache_free(extent_node_slab, en);
}
/*
* Flow to release an extent_node:
* 1. list_del_init
* 2. __detach_extent_node
* 3. kmem_cache_free.
*/
static void __release_extent_node(struct f2fs_sb_info *sbi,
struct extent_tree *et, struct extent_node *en)
{
spin_lock(&sbi->extent_lock);
f2fs_bug_on(sbi, list_empty(&en->list));
list_del_init(&en->list);
spin_unlock(&sbi->extent_lock);
__detach_extent_node(sbi, et, en);
}
static struct extent_tree *__grab_extent_tree(struct inode *inode)
{
struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
struct extent_tree *et;
nid_t ino = inode->i_ino;
down_write(&sbi->extent_tree_lock);
et = radix_tree_lookup(&sbi->extent_tree_root, ino);
if (!et) {
et = f2fs_kmem_cache_alloc(extent_tree_slab, GFP_NOFS);
f2fs_radix_tree_insert(&sbi->extent_tree_root, ino, et);
memset(et, 0, sizeof(struct extent_tree));
et->ino = ino;
et->root = RB_ROOT;
et->cached_en = NULL;
rwlock_init(&et->lock);
INIT_LIST_HEAD(&et->list);
atomic_set(&et->node_cnt, 0);
atomic_inc(&sbi->total_ext_tree);
} else {
atomic_dec(&sbi->total_zombie_tree);
list_del_init(&et->list);
}
up_write(&sbi->extent_tree_lock);
/* never died until evict_inode */
F2FS_I(inode)->extent_tree = et;
return et;
}
static struct extent_node *__lookup_extent_tree(struct f2fs_sb_info *sbi,
struct extent_tree *et, unsigned int fofs)
{
struct rb_node *node = et->root.rb_node;
struct extent_node *en = et->cached_en;
if (en) {
struct extent_info *cei = &en->ei;
if (cei->fofs <= fofs && cei->fofs + cei->len > fofs) {
stat_inc_cached_node_hit(sbi);
return en;
}
}
while (node) {
en = rb_entry(node, struct extent_node, rb_node);
if (fofs < en->ei.fofs) {
node = node->rb_left;
} else if (fofs >= en->ei.fofs + en->ei.len) {
node = node->rb_right;
} else {
stat_inc_rbtree_node_hit(sbi);
return en;
}
}
return NULL;
}
static struct extent_node *__init_extent_tree(struct f2fs_sb_info *sbi,
struct extent_tree *et, struct extent_info *ei)
{
struct rb_node **p = &et->root.rb_node;
struct extent_node *en;
en = __attach_extent_node(sbi, et, ei, NULL, p);
if (!en)
return NULL;
et->largest = en->ei;
et->cached_en = en;
return en;
}
static unsigned int __free_extent_tree(struct f2fs_sb_info *sbi,
struct extent_tree *et)
{
struct rb_node *node, *next;
struct extent_node *en;
unsigned int count = atomic_read(&et->node_cnt);
node = rb_first(&et->root);
while (node) {
next = rb_next(node);
en = rb_entry(node, struct extent_node, rb_node);
__release_extent_node(sbi, et, en);
node = next;
}
return count - atomic_read(&et->node_cnt);
}
static void __drop_largest_extent(struct inode *inode,
pgoff_t fofs, unsigned int len)
{
struct extent_info *largest = &F2FS_I(inode)->extent_tree->largest;
if (fofs < largest->fofs + largest->len && fofs + len > largest->fofs)
largest->len = 0;
}
/* return true, if inode page is changed */
bool f2fs_init_extent_tree(struct inode *inode, struct f2fs_extent *i_ext)
{
struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
struct extent_tree *et;
struct extent_node *en;
struct extent_info ei;
if (!f2fs_may_extent_tree(inode)) {
/* drop largest extent */
if (i_ext && i_ext->len) {
i_ext->len = 0;
return true;
}
return false;
}
et = __grab_extent_tree(inode);
if (!i_ext || !i_ext->len)
return false;
get_extent_info(&ei, i_ext);
write_lock(&et->lock);
if (atomic_read(&et->node_cnt))
goto out;
en = __init_extent_tree(sbi, et, &ei);
if (en) {
spin_lock(&sbi->extent_lock);
list_add_tail(&en->list, &sbi->extent_list);
spin_unlock(&sbi->extent_lock);
}
out:
write_unlock(&et->lock);
return false;
}
static bool f2fs_lookup_extent_tree(struct inode *inode, pgoff_t pgofs,
struct extent_info *ei)
{
struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
struct extent_tree *et = F2FS_I(inode)->extent_tree;
struct extent_node *en;
bool ret = false;
f2fs_bug_on(sbi, !et);
trace_f2fs_lookup_extent_tree_start(inode, pgofs);
read_lock(&et->lock);
if (et->largest.fofs <= pgofs &&
et->largest.fofs + et->largest.len > pgofs) {
*ei = et->largest;
ret = true;
stat_inc_largest_node_hit(sbi);
goto out;
}
en = __lookup_extent_tree(sbi, et, pgofs);
if (en) {
*ei = en->ei;
spin_lock(&sbi->extent_lock);
if (!list_empty(&en->list)) {
list_move_tail(&en->list, &sbi->extent_list);
et->cached_en = en;
}
spin_unlock(&sbi->extent_lock);
ret = true;
}
out:
stat_inc_total_hit(sbi);
read_unlock(&et->lock);
trace_f2fs_lookup_extent_tree_end(inode, pgofs, ei);
return ret;
}
/*
* lookup extent at @fofs, if hit, return the extent
* if not, return NULL and
* @prev_ex: extent before fofs
* @next_ex: extent after fofs
* @insert_p: insert point for new extent at fofs
* in order to simpfy the insertion after.
* tree must stay unchanged between lookup and insertion.
*/
static struct extent_node *__lookup_extent_tree_ret(struct extent_tree *et,
unsigned int fofs,
struct extent_node **prev_ex,
struct extent_node **next_ex,
struct rb_node ***insert_p,
struct rb_node **insert_parent)
{
struct rb_node **pnode = &et->root.rb_node;
struct rb_node *parent = NULL, *tmp_node;
struct extent_node *en = et->cached_en;
*insert_p = NULL;
*insert_parent = NULL;
*prev_ex = NULL;
*next_ex = NULL;
if (RB_EMPTY_ROOT(&et->root))
return NULL;
if (en) {
struct extent_info *cei = &en->ei;
if (cei->fofs <= fofs && cei->fofs + cei->len > fofs)
goto lookup_neighbors;
}
while (*pnode) {
parent = *pnode;
en = rb_entry(*pnode, struct extent_node, rb_node);
if (fofs < en->ei.fofs)
pnode = &(*pnode)->rb_left;
else if (fofs >= en->ei.fofs + en->ei.len)
pnode = &(*pnode)->rb_right;
else
goto lookup_neighbors;
}
*insert_p = pnode;
*insert_parent = parent;
en = rb_entry(parent, struct extent_node, rb_node);
tmp_node = parent;
if (parent && fofs > en->ei.fofs)
tmp_node = rb_next(parent);
*next_ex = tmp_node ?
rb_entry(tmp_node, struct extent_node, rb_node) : NULL;
tmp_node = parent;
if (parent && fofs < en->ei.fofs)
tmp_node = rb_prev(parent);
*prev_ex = tmp_node ?
rb_entry(tmp_node, struct extent_node, rb_node) : NULL;
return NULL;
lookup_neighbors:
if (fofs == en->ei.fofs) {
/* lookup prev node for merging backward later */
tmp_node = rb_prev(&en->rb_node);
*prev_ex = tmp_node ?
rb_entry(tmp_node, struct extent_node, rb_node) : NULL;
}
if (fofs == en->ei.fofs + en->ei.len - 1) {
/* lookup next node for merging frontward later */
tmp_node = rb_next(&en->rb_node);
*next_ex = tmp_node ?
rb_entry(tmp_node, struct extent_node, rb_node) : NULL;
}
return en;
}
static struct extent_node *__try_merge_extent_node(struct f2fs_sb_info *sbi,
struct extent_tree *et, struct extent_info *ei,
struct extent_node *prev_ex,
struct extent_node *next_ex)
{
struct extent_node *en = NULL;
if (prev_ex && __is_back_mergeable(ei, &prev_ex->ei)) {
prev_ex->ei.len += ei->len;
ei = &prev_ex->ei;
en = prev_ex;
}
if (next_ex && __is_front_mergeable(ei, &next_ex->ei)) {
if (en)
__release_extent_node(sbi, et, prev_ex);
next_ex->ei.fofs = ei->fofs;
next_ex->ei.blk = ei->blk;
next_ex->ei.len += ei->len;
en = next_ex;
}
if (!en)
return NULL;
__try_update_largest_extent(et, en);
spin_lock(&sbi->extent_lock);
if (!list_empty(&en->list)) {
list_move_tail(&en->list, &sbi->extent_list);
et->cached_en = en;
}
spin_unlock(&sbi->extent_lock);
return en;
}
static struct extent_node *__insert_extent_tree(struct f2fs_sb_info *sbi,
struct extent_tree *et, struct extent_info *ei,
struct rb_node **insert_p,
struct rb_node *insert_parent)
{
struct rb_node **p = &et->root.rb_node;
struct rb_node *parent = NULL;
struct extent_node *en = NULL;
if (insert_p && insert_parent) {
parent = insert_parent;
p = insert_p;
goto do_insert;
}
while (*p) {
parent = *p;
en = rb_entry(parent, struct extent_node, rb_node);
if (ei->fofs < en->ei.fofs)
p = &(*p)->rb_left;
else if (ei->fofs >= en->ei.fofs + en->ei.len)
p = &(*p)->rb_right;
else
f2fs_bug_on(sbi, 1);
}
do_insert:
en = __attach_extent_node(sbi, et, ei, parent, p);
if (!en)
return NULL;
__try_update_largest_extent(et, en);
/* update in global extent list */
spin_lock(&sbi->extent_lock);
list_add_tail(&en->list, &sbi->extent_list);
et->cached_en = en;
spin_unlock(&sbi->extent_lock);
return en;
}
static unsigned int f2fs_update_extent_tree_range(struct inode *inode,
pgoff_t fofs, block_t blkaddr, unsigned int len)
{
struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
struct extent_tree *et = F2FS_I(inode)->extent_tree;
struct extent_node *en = NULL, *en1 = NULL;
struct extent_node *prev_en = NULL, *next_en = NULL;
struct extent_info ei, dei, prev;
struct rb_node **insert_p = NULL, *insert_parent = NULL;
unsigned int end = fofs + len;
unsigned int pos = (unsigned int)fofs;
if (!et)
return false;
trace_f2fs_update_extent_tree_range(inode, fofs, blkaddr, len);
write_lock(&et->lock);
if (is_inode_flag_set(F2FS_I(inode), FI_NO_EXTENT)) {
write_unlock(&et->lock);
return false;
}
prev = et->largest;
dei.len = 0;
/*
* drop largest extent before lookup, in case it's already
* been shrunk from extent tree
*/
__drop_largest_extent(inode, fofs, len);
/* 1. lookup first extent node in range [fofs, fofs + len - 1] */
en = __lookup_extent_tree_ret(et, fofs, &prev_en, &next_en,
&insert_p, &insert_parent);
if (!en)
en = next_en;
/* 2. invlidate all extent nodes in range [fofs, fofs + len - 1] */
while (en && en->ei.fofs < end) {
unsigned int org_end;
int parts = 0; /* # of parts current extent split into */
next_en = en1 = NULL;
dei = en->ei;
org_end = dei.fofs + dei.len;
f2fs_bug_on(sbi, pos >= org_end);
if (pos > dei.fofs && pos - dei.fofs >= F2FS_MIN_EXTENT_LEN) {
en->ei.len = pos - en->ei.fofs;
prev_en = en;
parts = 1;
}
if (end < org_end && org_end - end >= F2FS_MIN_EXTENT_LEN) {
if (parts) {
set_extent_info(&ei, end,
end - dei.fofs + dei.blk,
org_end - end);
en1 = __insert_extent_tree(sbi, et, &ei,
NULL, NULL);
next_en = en1;
} else {
en->ei.fofs = end;
en->ei.blk += end - dei.fofs;
en->ei.len -= end - dei.fofs;
next_en = en;
}
parts++;
}
if (!next_en) {
struct rb_node *node = rb_next(&en->rb_node);
next_en = node ?
rb_entry(node, struct extent_node, rb_node)
: NULL;
}
if (parts)
__try_update_largest_extent(et, en);
else
__release_extent_node(sbi, et, en);
/*
* if original extent is split into zero or two parts, extent
* tree has been altered by deletion or insertion, therefore
* invalidate pointers regard to tree.
*/
if (parts != 1) {
insert_p = NULL;
insert_parent = NULL;
}
en = next_en;
}
/* 3. update extent in extent cache */
if (blkaddr) {
set_extent_info(&ei, fofs, blkaddr, len);
if (!__try_merge_extent_node(sbi, et, &ei, prev_en, next_en))
__insert_extent_tree(sbi, et, &ei,
insert_p, insert_parent);
/* give up extent_cache, if split and small updates happen */
if (dei.len >= 1 &&
prev.len < F2FS_MIN_EXTENT_LEN &&
et->largest.len < F2FS_MIN_EXTENT_LEN) {
et->largest.len = 0;
set_inode_flag(F2FS_I(inode), FI_NO_EXTENT);
}
}
if (is_inode_flag_set(F2FS_I(inode), FI_NO_EXTENT))
__free_extent_tree(sbi, et);
write_unlock(&et->lock);
return !__is_extent_same(&prev, &et->largest);
}
unsigned int f2fs_shrink_extent_tree(struct f2fs_sb_info *sbi, int nr_shrink)
{
struct extent_tree *et, *next;
struct extent_node *en;
unsigned int node_cnt = 0, tree_cnt = 0;
int remained;
if (!test_opt(sbi, EXTENT_CACHE))
return 0;
if (!atomic_read(&sbi->total_zombie_tree))
goto free_node;
if (!down_write_trylock(&sbi->extent_tree_lock))
goto out;
/* 1. remove unreferenced extent tree */
list_for_each_entry_safe(et, next, &sbi->zombie_list, list) {
if (atomic_read(&et->node_cnt)) {
write_lock(&et->lock);
node_cnt += __free_extent_tree(sbi, et);
write_unlock(&et->lock);
}
f2fs_bug_on(sbi, atomic_read(&et->node_cnt));
list_del_init(&et->list);
radix_tree_delete(&sbi->extent_tree_root, et->ino);
kmem_cache_free(extent_tree_slab, et);
atomic_dec(&sbi->total_ext_tree);
atomic_dec(&sbi->total_zombie_tree);
tree_cnt++;
if (node_cnt + tree_cnt >= nr_shrink)
goto unlock_out;
cond_resched();
}
up_write(&sbi->extent_tree_lock);
free_node:
/* 2. remove LRU extent entries */
if (!down_write_trylock(&sbi->extent_tree_lock))
goto out;
remained = nr_shrink - (node_cnt + tree_cnt);
spin_lock(&sbi->extent_lock);
for (; remained > 0; remained--) {
if (list_empty(&sbi->extent_list))
break;
en = list_first_entry(&sbi->extent_list,
struct extent_node, list);
et = en->et;
if (!write_trylock(&et->lock)) {
/* refresh this extent node's position in extent list */
list_move_tail(&en->list, &sbi->extent_list);
continue;
}
list_del_init(&en->list);
spin_unlock(&sbi->extent_lock);
__detach_extent_node(sbi, et, en);
write_unlock(&et->lock);
node_cnt++;
spin_lock(&sbi->extent_lock);
}
spin_unlock(&sbi->extent_lock);
unlock_out:
up_write(&sbi->extent_tree_lock);
out:
trace_f2fs_shrink_extent_tree(sbi, node_cnt, tree_cnt);
return node_cnt + tree_cnt;
}
unsigned int f2fs_destroy_extent_node(struct inode *inode)
{
struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
struct extent_tree *et = F2FS_I(inode)->extent_tree;
unsigned int node_cnt = 0;
if (!et || !atomic_read(&et->node_cnt))
return 0;
write_lock(&et->lock);
node_cnt = __free_extent_tree(sbi, et);
write_unlock(&et->lock);
return node_cnt;
}
void f2fs_destroy_extent_tree(struct inode *inode)
{
struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
struct extent_tree *et = F2FS_I(inode)->extent_tree;
unsigned int node_cnt = 0;
if (!et)
return;
if (inode->i_nlink && !is_bad_inode(inode) &&
atomic_read(&et->node_cnt)) {
down_write(&sbi->extent_tree_lock);
list_add_tail(&et->list, &sbi->zombie_list);
atomic_inc(&sbi->total_zombie_tree);
up_write(&sbi->extent_tree_lock);
return;
}
/* free all extent info belong to this extent tree */
node_cnt = f2fs_destroy_extent_node(inode);
/* delete extent tree entry in radix tree */
down_write(&sbi->extent_tree_lock);
f2fs_bug_on(sbi, atomic_read(&et->node_cnt));
radix_tree_delete(&sbi->extent_tree_root, inode->i_ino);
kmem_cache_free(extent_tree_slab, et);
atomic_dec(&sbi->total_ext_tree);
up_write(&sbi->extent_tree_lock);
F2FS_I(inode)->extent_tree = NULL;
trace_f2fs_destroy_extent_tree(inode, node_cnt);
}
bool f2fs_lookup_extent_cache(struct inode *inode, pgoff_t pgofs,
struct extent_info *ei)
{
if (!f2fs_may_extent_tree(inode))
return false;
return f2fs_lookup_extent_tree(inode, pgofs, ei);
}
void f2fs_update_extent_cache(struct dnode_of_data *dn)
{
pgoff_t fofs;
block_t blkaddr;
if (!f2fs_may_extent_tree(dn->inode))
return;
if (dn->data_blkaddr == NEW_ADDR)
blkaddr = NULL_ADDR;
else
blkaddr = dn->data_blkaddr;
fofs = start_bidx_of_node(ofs_of_node(dn->node_page), dn->inode) +
dn->ofs_in_node;
if (f2fs_update_extent_tree_range(dn->inode, fofs, blkaddr, 1))
sync_inode_page(dn);
}
void f2fs_update_extent_cache_range(struct dnode_of_data *dn,
pgoff_t fofs, block_t blkaddr, unsigned int len)
{
if (!f2fs_may_extent_tree(dn->inode))
return;
if (f2fs_update_extent_tree_range(dn->inode, fofs, blkaddr, len))
sync_inode_page(dn);
}
void init_extent_cache_info(struct f2fs_sb_info *sbi)
{
INIT_RADIX_TREE(&sbi->extent_tree_root, GFP_NOIO);
init_rwsem(&sbi->extent_tree_lock);
INIT_LIST_HEAD(&sbi->extent_list);
spin_lock_init(&sbi->extent_lock);
atomic_set(&sbi->total_ext_tree, 0);
INIT_LIST_HEAD(&sbi->zombie_list);
atomic_set(&sbi->total_zombie_tree, 0);
atomic_set(&sbi->total_ext_node, 0);
}
int __init create_extent_cache(void)
{
extent_tree_slab = f2fs_kmem_cache_create("f2fs_extent_tree",
sizeof(struct extent_tree));
if (!extent_tree_slab)
return -ENOMEM;
extent_node_slab = f2fs_kmem_cache_create("f2fs_extent_node",
sizeof(struct extent_node));
if (!extent_node_slab) {
kmem_cache_destroy(extent_tree_slab);
return -ENOMEM;
}
return 0;
}
void destroy_extent_cache(void)
{
kmem_cache_destroy(extent_node_slab);
kmem_cache_destroy(extent_tree_slab);
}