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OpenCloudOS-Kernel/fs/f2fs/gc.c

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/*
* fs/f2fs/gc.c
*
* Copyright (c) 2012 Samsung Electronics Co., Ltd.
* http://www.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/module.h>
#include <linux/backing-dev.h>
#include <linux/init.h>
#include <linux/f2fs_fs.h>
#include <linux/kthread.h>
#include <linux/delay.h>
#include <linux/freezer.h>
#include "f2fs.h"
#include "node.h"
#include "segment.h"
#include "gc.h"
#include <trace/events/f2fs.h>
static int gc_thread_func(void *data)
{
struct f2fs_sb_info *sbi = data;
struct f2fs_gc_kthread *gc_th = sbi->gc_thread;
wait_queue_head_t *wq = &sbi->gc_thread->gc_wait_queue_head;
long wait_ms;
wait_ms = gc_th->min_sleep_time;
do {
if (try_to_freeze())
continue;
else
wait_event_interruptible_timeout(*wq,
kthread_should_stop(),
msecs_to_jiffies(wait_ms));
if (kthread_should_stop())
break;
if (sbi->sb->s_writers.frozen >= SB_FREEZE_WRITE) {
increase_sleep_time(gc_th, &wait_ms);
continue;
}
#ifdef CONFIG_F2FS_FAULT_INJECTION
if (time_to_inject(sbi, FAULT_CHECKPOINT))
f2fs_stop_checkpoint(sbi, false);
#endif
/*
* [GC triggering condition]
* 0. GC is not conducted currently.
* 1. There are enough dirty segments.
* 2. IO subsystem is idle by checking the # of writeback pages.
* 3. IO subsystem is idle by checking the # of requests in
* bdev's request list.
*
* Note) We have to avoid triggering GCs frequently.
* Because it is possible that some segments can be
* invalidated soon after by user update or deletion.
* So, I'd like to wait some time to collect dirty segments.
*/
if (!mutex_trylock(&sbi->gc_mutex))
continue;
if (!is_idle(sbi)) {
increase_sleep_time(gc_th, &wait_ms);
mutex_unlock(&sbi->gc_mutex);
continue;
}
if (has_enough_invalid_blocks(sbi))
decrease_sleep_time(gc_th, &wait_ms);
else
increase_sleep_time(gc_th, &wait_ms);
stat_inc_bggc_count(sbi);
/* if return value is not zero, no victim was selected */
if (f2fs_gc(sbi, test_opt(sbi, FORCE_FG_GC)))
wait_ms = gc_th->no_gc_sleep_time;
trace_f2fs_background_gc(sbi->sb, wait_ms,
prefree_segments(sbi), free_segments(sbi));
/* balancing f2fs's metadata periodically */
f2fs_balance_fs_bg(sbi);
} while (!kthread_should_stop());
return 0;
}
int start_gc_thread(struct f2fs_sb_info *sbi)
{
struct f2fs_gc_kthread *gc_th;
dev_t dev = sbi->sb->s_bdev->bd_dev;
int err = 0;
gc_th = f2fs_kmalloc(sbi, sizeof(struct f2fs_gc_kthread), GFP_KERNEL);
if (!gc_th) {
err = -ENOMEM;
goto out;
}
gc_th->min_sleep_time = DEF_GC_THREAD_MIN_SLEEP_TIME;
gc_th->max_sleep_time = DEF_GC_THREAD_MAX_SLEEP_TIME;
gc_th->no_gc_sleep_time = DEF_GC_THREAD_NOGC_SLEEP_TIME;
gc_th->gc_idle = 0;
sbi->gc_thread = gc_th;
init_waitqueue_head(&sbi->gc_thread->gc_wait_queue_head);
sbi->gc_thread->f2fs_gc_task = kthread_run(gc_thread_func, sbi,
"f2fs_gc-%u:%u", MAJOR(dev), MINOR(dev));
if (IS_ERR(gc_th->f2fs_gc_task)) {
err = PTR_ERR(gc_th->f2fs_gc_task);
kfree(gc_th);
sbi->gc_thread = NULL;
}
out:
return err;
}
void stop_gc_thread(struct f2fs_sb_info *sbi)
{
struct f2fs_gc_kthread *gc_th = sbi->gc_thread;
if (!gc_th)
return;
kthread_stop(gc_th->f2fs_gc_task);
kfree(gc_th);
sbi->gc_thread = NULL;
}
static int select_gc_type(struct f2fs_gc_kthread *gc_th, int gc_type)
{
int gc_mode = (gc_type == BG_GC) ? GC_CB : GC_GREEDY;
if (gc_th && gc_th->gc_idle) {
if (gc_th->gc_idle == 1)
gc_mode = GC_CB;
else if (gc_th->gc_idle == 2)
gc_mode = GC_GREEDY;
}
return gc_mode;
}
static void select_policy(struct f2fs_sb_info *sbi, int gc_type,
int type, struct victim_sel_policy *p)
{
struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
if (p->alloc_mode == SSR) {
p->gc_mode = GC_GREEDY;
p->dirty_segmap = dirty_i->dirty_segmap[type];
p->max_search = dirty_i->nr_dirty[type];
p->ofs_unit = 1;
} else {
p->gc_mode = select_gc_type(sbi->gc_thread, gc_type);
p->dirty_segmap = dirty_i->dirty_segmap[DIRTY];
p->max_search = dirty_i->nr_dirty[DIRTY];
p->ofs_unit = sbi->segs_per_sec;
}
if (p->max_search > sbi->max_victim_search)
p->max_search = sbi->max_victim_search;
p->offset = sbi->last_victim[p->gc_mode];
}
static unsigned int get_max_cost(struct f2fs_sb_info *sbi,
struct victim_sel_policy *p)
{
/* SSR allocates in a segment unit */
if (p->alloc_mode == SSR)
return sbi->blocks_per_seg;
if (p->gc_mode == GC_GREEDY)
return sbi->blocks_per_seg * p->ofs_unit;
else if (p->gc_mode == GC_CB)
return UINT_MAX;
else /* No other gc_mode */
return 0;
}
static unsigned int check_bg_victims(struct f2fs_sb_info *sbi)
{
struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
unsigned int secno;
/*
* If the gc_type is FG_GC, we can select victim segments
* selected by background GC before.
* Those segments guarantee they have small valid blocks.
*/
for_each_set_bit(secno, dirty_i->victim_secmap, MAIN_SECS(sbi)) {
if (sec_usage_check(sbi, secno))
continue;
clear_bit(secno, dirty_i->victim_secmap);
return secno * sbi->segs_per_sec;
}
return NULL_SEGNO;
}
static unsigned int get_cb_cost(struct f2fs_sb_info *sbi, unsigned int segno)
{
struct sit_info *sit_i = SIT_I(sbi);
unsigned int secno = GET_SECNO(sbi, segno);
unsigned int start = secno * sbi->segs_per_sec;
unsigned long long mtime = 0;
unsigned int vblocks;
unsigned char age = 0;
unsigned char u;
unsigned int i;
for (i = 0; i < sbi->segs_per_sec; i++)
mtime += get_seg_entry(sbi, start + i)->mtime;
vblocks = get_valid_blocks(sbi, segno, sbi->segs_per_sec);
mtime = div_u64(mtime, sbi->segs_per_sec);
vblocks = div_u64(vblocks, sbi->segs_per_sec);
u = (vblocks * 100) >> sbi->log_blocks_per_seg;
/* Handle if the system time has changed by the user */
if (mtime < sit_i->min_mtime)
sit_i->min_mtime = mtime;
if (mtime > sit_i->max_mtime)
sit_i->max_mtime = mtime;
if (sit_i->max_mtime != sit_i->min_mtime)
age = 100 - div64_u64(100 * (mtime - sit_i->min_mtime),
sit_i->max_mtime - sit_i->min_mtime);
return UINT_MAX - ((100 * (100 - u) * age) / (100 + u));
}
static inline unsigned int get_gc_cost(struct f2fs_sb_info *sbi,
unsigned int segno, struct victim_sel_policy *p)
{
if (p->alloc_mode == SSR)
return get_seg_entry(sbi, segno)->ckpt_valid_blocks;
/* alloc_mode == LFS */
if (p->gc_mode == GC_GREEDY)
return get_valid_blocks(sbi, segno, sbi->segs_per_sec);
else
return get_cb_cost(sbi, segno);
}
static unsigned int count_bits(const unsigned long *addr,
unsigned int offset, unsigned int len)
{
unsigned int end = offset + len, sum = 0;
while (offset < end) {
if (test_bit(offset++, addr))
++sum;
}
return sum;
}
/*
* This function is called from two paths.
* One is garbage collection and the other is SSR segment selection.
* When it is called during GC, it just gets a victim segment
* and it does not remove it from dirty seglist.
* When it is called from SSR segment selection, it finds a segment
* which has minimum valid blocks and removes it from dirty seglist.
*/
static int get_victim_by_default(struct f2fs_sb_info *sbi,
unsigned int *result, int gc_type, int type, char alloc_mode)
{
struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
struct victim_sel_policy p;
unsigned int secno, last_victim;
unsigned int last_segment = MAIN_SEGS(sbi);
unsigned int nsearched = 0;
mutex_lock(&dirty_i->seglist_lock);
p.alloc_mode = alloc_mode;
select_policy(sbi, gc_type, type, &p);
p.min_segno = NULL_SEGNO;
p.min_cost = get_max_cost(sbi, &p);
if (p.max_search == 0)
goto out;
last_victim = sbi->last_victim[p.gc_mode];
if (p.alloc_mode == LFS && gc_type == FG_GC) {
p.min_segno = check_bg_victims(sbi);
if (p.min_segno != NULL_SEGNO)
goto got_it;
}
while (1) {
unsigned long cost;
unsigned int segno;
segno = find_next_bit(p.dirty_segmap, last_segment, p.offset);
if (segno >= last_segment) {
if (sbi->last_victim[p.gc_mode]) {
last_segment = sbi->last_victim[p.gc_mode];
sbi->last_victim[p.gc_mode] = 0;
p.offset = 0;
continue;
}
break;
}
p.offset = segno + p.ofs_unit;
if (p.ofs_unit > 1) {
p.offset -= segno % p.ofs_unit;
nsearched += count_bits(p.dirty_segmap,
p.offset - p.ofs_unit,
p.ofs_unit);
} else {
nsearched++;
}
secno = GET_SECNO(sbi, segno);
if (sec_usage_check(sbi, secno))
goto next;
if (gc_type == BG_GC && test_bit(secno, dirty_i->victim_secmap))
goto next;
cost = get_gc_cost(sbi, segno, &p);
if (p.min_cost > cost) {
p.min_segno = segno;
p.min_cost = cost;
}
next:
if (nsearched >= p.max_search) {
if (!sbi->last_victim[p.gc_mode] && segno <= last_victim)
sbi->last_victim[p.gc_mode] = last_victim + 1;
else
sbi->last_victim[p.gc_mode] = segno + 1;
break;
}
}
if (p.min_segno != NULL_SEGNO) {
got_it:
if (p.alloc_mode == LFS) {
secno = GET_SECNO(sbi, p.min_segno);
if (gc_type == FG_GC)
sbi->cur_victim_sec = secno;
else
set_bit(secno, dirty_i->victim_secmap);
}
*result = (p.min_segno / p.ofs_unit) * p.ofs_unit;
trace_f2fs_get_victim(sbi->sb, type, gc_type, &p,
sbi->cur_victim_sec,
prefree_segments(sbi), free_segments(sbi));
}
out:
mutex_unlock(&dirty_i->seglist_lock);
return (p.min_segno == NULL_SEGNO) ? 0 : 1;
}
static const struct victim_selection default_v_ops = {
.get_victim = get_victim_by_default,
};
static struct inode *find_gc_inode(struct gc_inode_list *gc_list, nid_t ino)
{
struct inode_entry *ie;
ie = radix_tree_lookup(&gc_list->iroot, ino);
if (ie)
return ie->inode;
return NULL;
}
static void add_gc_inode(struct gc_inode_list *gc_list, struct inode *inode)
{
struct inode_entry *new_ie;
if (inode == find_gc_inode(gc_list, inode->i_ino)) {
iput(inode);
return;
}
new_ie = f2fs_kmem_cache_alloc(inode_entry_slab, GFP_NOFS);
new_ie->inode = inode;
f2fs_radix_tree_insert(&gc_list->iroot, inode->i_ino, new_ie);
list_add_tail(&new_ie->list, &gc_list->ilist);
}
static void put_gc_inode(struct gc_inode_list *gc_list)
{
struct inode_entry *ie, *next_ie;
list_for_each_entry_safe(ie, next_ie, &gc_list->ilist, list) {
radix_tree_delete(&gc_list->iroot, ie->inode->i_ino);
iput(ie->inode);
list_del(&ie->list);
kmem_cache_free(inode_entry_slab, ie);
}
}
static int check_valid_map(struct f2fs_sb_info *sbi,
unsigned int segno, int offset)
{
struct sit_info *sit_i = SIT_I(sbi);
struct seg_entry *sentry;
int ret;
mutex_lock(&sit_i->sentry_lock);
sentry = get_seg_entry(sbi, segno);
ret = f2fs_test_bit(offset, sentry->cur_valid_map);
mutex_unlock(&sit_i->sentry_lock);
return ret;
}
/*
* This function compares node address got in summary with that in NAT.
* On validity, copy that node with cold status, otherwise (invalid node)
* ignore that.
*/
static void gc_node_segment(struct f2fs_sb_info *sbi,
struct f2fs_summary *sum, unsigned int segno, int gc_type)
{
struct f2fs_summary *entry;
block_t start_addr;
int off;
int phase = 0;
start_addr = START_BLOCK(sbi, segno);
next_step:
entry = sum;
for (off = 0; off < sbi->blocks_per_seg; off++, entry++) {
nid_t nid = le32_to_cpu(entry->nid);
struct page *node_page;
struct node_info ni;
/* stop BG_GC if there is not enough free sections. */
if (gc_type == BG_GC && has_not_enough_free_secs(sbi, 0, 0))
return;
if (check_valid_map(sbi, segno, off) == 0)
continue;
if (phase == 0) {
ra_meta_pages(sbi, NAT_BLOCK_OFFSET(nid), 1,
META_NAT, true);
continue;
}
if (phase == 1) {
ra_node_page(sbi, nid);
continue;
}
/* phase == 2 */
node_page = get_node_page(sbi, nid);
if (IS_ERR(node_page))
continue;
/* block may become invalid during get_node_page */
if (check_valid_map(sbi, segno, off) == 0) {
f2fs_put_page(node_page, 1);
continue;
}
get_node_info(sbi, nid, &ni);
if (ni.blk_addr != start_addr + off) {
f2fs_put_page(node_page, 1);
continue;
}
move_node_page(node_page, gc_type);
stat_inc_node_blk_count(sbi, 1, gc_type);
}
if (++phase < 3)
goto next_step;
}
/*
* Calculate start block index indicating the given node offset.
* Be careful, caller should give this node offset only indicating direct node
* blocks. If any node offsets, which point the other types of node blocks such
* as indirect or double indirect node blocks, are given, it must be a caller's
* bug.
*/
block_t start_bidx_of_node(unsigned int node_ofs, struct inode *inode)
{
unsigned int indirect_blks = 2 * NIDS_PER_BLOCK + 4;
unsigned int bidx;
if (node_ofs == 0)
return 0;
if (node_ofs <= 2) {
bidx = node_ofs - 1;
} else if (node_ofs <= indirect_blks) {
int dec = (node_ofs - 4) / (NIDS_PER_BLOCK + 1);
bidx = node_ofs - 2 - dec;
} else {
int dec = (node_ofs - indirect_blks - 3) / (NIDS_PER_BLOCK + 1);
bidx = node_ofs - 5 - dec;
}
return bidx * ADDRS_PER_BLOCK + ADDRS_PER_INODE(inode);
}
static bool is_alive(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
struct node_info *dni, block_t blkaddr, unsigned int *nofs)
{
struct page *node_page;
nid_t nid;
unsigned int ofs_in_node;
block_t source_blkaddr;
nid = le32_to_cpu(sum->nid);
ofs_in_node = le16_to_cpu(sum->ofs_in_node);
node_page = get_node_page(sbi, nid);
if (IS_ERR(node_page))
return false;
get_node_info(sbi, nid, dni);
if (sum->version != dni->version) {
f2fs_put_page(node_page, 1);
return false;
}
*nofs = ofs_of_node(node_page);
source_blkaddr = datablock_addr(node_page, ofs_in_node);
f2fs_put_page(node_page, 1);
if (source_blkaddr != blkaddr)
return false;
return true;
}
static void move_encrypted_block(struct inode *inode, block_t bidx)
{
struct f2fs_io_info fio = {
.sbi = F2FS_I_SB(inode),
.type = DATA,
.op = REQ_OP_READ,
.op_flags = READ_SYNC,
.encrypted_page = NULL,
};
struct dnode_of_data dn;
struct f2fs_summary sum;
struct node_info ni;
struct page *page;
block_t newaddr;
int err;
/* do not read out */
page = f2fs_grab_cache_page(inode->i_mapping, bidx, false);
if (!page)
return;
set_new_dnode(&dn, inode, NULL, NULL, 0);
err = get_dnode_of_data(&dn, bidx, LOOKUP_NODE);
if (err)
goto out;
if (unlikely(dn.data_blkaddr == NULL_ADDR)) {
ClearPageUptodate(page);
goto put_out;
}
/*
* don't cache encrypted data into meta inode until previous dirty
* data were writebacked to avoid racing between GC and flush.
*/
f2fs_wait_on_page_writeback(page, DATA, true);
get_node_info(fio.sbi, dn.nid, &ni);
set_summary(&sum, dn.nid, dn.ofs_in_node, ni.version);
/* read page */
fio.page = page;
fio.new_blkaddr = fio.old_blkaddr = dn.data_blkaddr;
allocate_data_block(fio.sbi, NULL, fio.old_blkaddr, &newaddr,
&sum, CURSEG_COLD_DATA);
fio.encrypted_page = pagecache_get_page(META_MAPPING(fio.sbi), newaddr,
FGP_LOCK | FGP_CREAT, GFP_NOFS);
if (!fio.encrypted_page) {
err = -ENOMEM;
goto recover_block;
}
err = f2fs_submit_page_bio(&fio);
if (err)
goto put_page_out;
/* write page */
lock_page(fio.encrypted_page);
if (unlikely(fio.encrypted_page->mapping != META_MAPPING(fio.sbi))) {
err = -EIO;
goto put_page_out;
}
if (unlikely(!PageUptodate(fio.encrypted_page))) {
err = -EIO;
goto put_page_out;
}
set_page_dirty(fio.encrypted_page);
f2fs_wait_on_page_writeback(fio.encrypted_page, DATA, true);
if (clear_page_dirty_for_io(fio.encrypted_page))
dec_page_count(fio.sbi, F2FS_DIRTY_META);
set_page_writeback(fio.encrypted_page);
/* allocate block address */
f2fs_wait_on_page_writeback(dn.node_page, NODE, true);
fio.op = REQ_OP_WRITE;
fio.op_flags = WRITE_SYNC;
fio.new_blkaddr = newaddr;
f2fs_submit_page_mbio(&fio);
f2fs_update_data_blkaddr(&dn, newaddr);
set_inode_flag(inode, FI_APPEND_WRITE);
if (page->index == 0)
set_inode_flag(inode, FI_FIRST_BLOCK_WRITTEN);
put_page_out:
f2fs_put_page(fio.encrypted_page, 1);
recover_block:
if (err)
__f2fs_replace_block(fio.sbi, &sum, newaddr, fio.old_blkaddr,
true, true);
put_out:
f2fs_put_dnode(&dn);
out:
f2fs_put_page(page, 1);
}
static void move_data_page(struct inode *inode, block_t bidx, int gc_type)
{
struct page *page;
page = get_lock_data_page(inode, bidx, true);
if (IS_ERR(page))
return;
if (gc_type == BG_GC) {
if (PageWriteback(page))
goto out;
set_page_dirty(page);
set_cold_data(page);
} else {
struct f2fs_io_info fio = {
.sbi = F2FS_I_SB(inode),
.type = DATA,
.op = REQ_OP_WRITE,
.op_flags = WRITE_SYNC,
.page = page,
.encrypted_page = NULL,
};
bool is_dirty = PageDirty(page);
int err;
retry:
set_page_dirty(page);
f2fs_wait_on_page_writeback(page, DATA, true);
if (clear_page_dirty_for_io(page))
inode_dec_dirty_pages(inode);
set_cold_data(page);
err = do_write_data_page(&fio);
if (err == -ENOMEM && is_dirty) {
congestion_wait(BLK_RW_ASYNC, HZ/50);
goto retry;
}
clear_cold_data(page);
}
out:
f2fs_put_page(page, 1);
}
/*
* This function tries to get parent node of victim data block, and identifies
* data block validity. If the block is valid, copy that with cold status and
* modify parent node.
* If the parent node is not valid or the data block address is different,
* the victim data block is ignored.
*/
static void gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
struct gc_inode_list *gc_list, unsigned int segno, int gc_type)
{
struct super_block *sb = sbi->sb;
struct f2fs_summary *entry;
block_t start_addr;
int off;
int phase = 0;
start_addr = START_BLOCK(sbi, segno);
next_step:
entry = sum;
for (off = 0; off < sbi->blocks_per_seg; off++, entry++) {
struct page *data_page;
struct inode *inode;
struct node_info dni; /* dnode info for the data */
unsigned int ofs_in_node, nofs;
block_t start_bidx;
nid_t nid = le32_to_cpu(entry->nid);
/* stop BG_GC if there is not enough free sections. */
if (gc_type == BG_GC && has_not_enough_free_secs(sbi, 0, 0))
return;
if (check_valid_map(sbi, segno, off) == 0)
continue;
if (phase == 0) {
ra_meta_pages(sbi, NAT_BLOCK_OFFSET(nid), 1,
META_NAT, true);
continue;
}
if (phase == 1) {
ra_node_page(sbi, nid);
continue;
}
/* Get an inode by ino with checking validity */
if (!is_alive(sbi, entry, &dni, start_addr + off, &nofs))
continue;
if (phase == 2) {
ra_node_page(sbi, dni.ino);
continue;
}
ofs_in_node = le16_to_cpu(entry->ofs_in_node);
if (phase == 3) {
inode = f2fs_iget(sb, dni.ino);
if (IS_ERR(inode) || is_bad_inode(inode))
continue;
/* if encrypted inode, let's go phase 3 */
if (f2fs_encrypted_inode(inode) &&
S_ISREG(inode->i_mode)) {
add_gc_inode(gc_list, inode);
continue;
}
start_bidx = start_bidx_of_node(nofs, inode);
data_page = get_read_data_page(inode,
start_bidx + ofs_in_node, REQ_RAHEAD,
true);
if (IS_ERR(data_page)) {
iput(inode);
continue;
}
f2fs_put_page(data_page, 0);
add_gc_inode(gc_list, inode);
continue;
}
/* phase 4 */
inode = find_gc_inode(gc_list, dni.ino);
if (inode) {
struct f2fs_inode_info *fi = F2FS_I(inode);
bool locked = false;
if (S_ISREG(inode->i_mode)) {
if (!down_write_trylock(&fi->dio_rwsem[READ]))
continue;
if (!down_write_trylock(
&fi->dio_rwsem[WRITE])) {
up_write(&fi->dio_rwsem[READ]);
continue;
}
locked = true;
}
start_bidx = start_bidx_of_node(nofs, inode)
+ ofs_in_node;
if (f2fs_encrypted_inode(inode) && S_ISREG(inode->i_mode))
move_encrypted_block(inode, start_bidx);
else
move_data_page(inode, start_bidx, gc_type);
if (locked) {
up_write(&fi->dio_rwsem[WRITE]);
up_write(&fi->dio_rwsem[READ]);
}
stat_inc_data_blk_count(sbi, 1, gc_type);
}
}
if (++phase < 5)
goto next_step;
}
static int __get_victim(struct f2fs_sb_info *sbi, unsigned int *victim,
int gc_type)
{
struct sit_info *sit_i = SIT_I(sbi);
int ret;
mutex_lock(&sit_i->sentry_lock);
ret = DIRTY_I(sbi)->v_ops->get_victim(sbi, victim, gc_type,
NO_CHECK_TYPE, LFS);
mutex_unlock(&sit_i->sentry_lock);
return ret;
}
static int do_garbage_collect(struct f2fs_sb_info *sbi,
unsigned int start_segno,
struct gc_inode_list *gc_list, int gc_type)
{
struct page *sum_page;
struct f2fs_summary_block *sum;
struct blk_plug plug;
unsigned int segno = start_segno;
unsigned int end_segno = start_segno + sbi->segs_per_sec;
int sec_freed = 0;
unsigned char type = IS_DATASEG(get_seg_entry(sbi, segno)->type) ?
SUM_TYPE_DATA : SUM_TYPE_NODE;
/* readahead multi ssa blocks those have contiguous address */
if (sbi->segs_per_sec > 1)
ra_meta_pages(sbi, GET_SUM_BLOCK(sbi, segno),
sbi->segs_per_sec, META_SSA, true);
/* reference all summary page */
while (segno < end_segno) {
sum_page = get_sum_page(sbi, segno++);
unlock_page(sum_page);
}
blk_start_plug(&plug);
for (segno = start_segno; segno < end_segno; segno++) {
/* find segment summary of victim */
sum_page = find_get_page(META_MAPPING(sbi),
GET_SUM_BLOCK(sbi, segno));
f2fs_put_page(sum_page, 0);
if (get_valid_blocks(sbi, segno, 1) == 0 ||
!PageUptodate(sum_page) ||
unlikely(f2fs_cp_error(sbi)))
goto next;
sum = page_address(sum_page);
f2fs_bug_on(sbi, type != GET_SUM_TYPE((&sum->footer)));
/*
* this is to avoid deadlock:
* - lock_page(sum_page) - f2fs_replace_block
* - check_valid_map() - mutex_lock(sentry_lock)
* - mutex_lock(sentry_lock) - change_curseg()
* - lock_page(sum_page)
*/
if (type == SUM_TYPE_NODE)
gc_node_segment(sbi, sum->entries, segno, gc_type);
else
gc_data_segment(sbi, sum->entries, gc_list, segno,
gc_type);
stat_inc_seg_count(sbi, type, gc_type);
next:
f2fs_put_page(sum_page, 0);
}
if (gc_type == FG_GC)
f2fs_submit_merged_bio(sbi,
(type == SUM_TYPE_NODE) ? NODE : DATA, WRITE);
blk_finish_plug(&plug);
if (gc_type == FG_GC &&
get_valid_blocks(sbi, start_segno, sbi->segs_per_sec) == 0)
sec_freed = 1;
stat_inc_call_count(sbi->stat_info);
return sec_freed;
}
int f2fs_gc(struct f2fs_sb_info *sbi, bool sync)
{
unsigned int segno;
int gc_type = sync ? FG_GC : BG_GC;
int sec_freed = 0;
int ret = -EINVAL;
struct cp_control cpc;
struct gc_inode_list gc_list = {
.ilist = LIST_HEAD_INIT(gc_list.ilist),
.iroot = RADIX_TREE_INIT(GFP_NOFS),
};
cpc.reason = __get_cp_reason(sbi);
gc_more:
segno = NULL_SEGNO;
if (unlikely(!(sbi->sb->s_flags & MS_ACTIVE)))
goto stop;
if (unlikely(f2fs_cp_error(sbi))) {
ret = -EIO;
goto stop;
}
if (gc_type == BG_GC && has_not_enough_free_secs(sbi, sec_freed, 0)) {
gc_type = FG_GC;
/*
* If there is no victim and no prefree segment but still not
* enough free sections, we should flush dent/node blocks and do
* garbage collections.
*/
if (__get_victim(sbi, &segno, gc_type) ||
prefree_segments(sbi)) {
ret = write_checkpoint(sbi, &cpc);
if (ret)
goto stop;
segno = NULL_SEGNO;
} else if (has_not_enough_free_secs(sbi, 0, 0)) {
ret = write_checkpoint(sbi, &cpc);
if (ret)
goto stop;
}
}
if (segno == NULL_SEGNO && !__get_victim(sbi, &segno, gc_type))
goto stop;
ret = 0;
if (do_garbage_collect(sbi, segno, &gc_list, gc_type) &&
gc_type == FG_GC)
sec_freed++;
if (gc_type == FG_GC)
sbi->cur_victim_sec = NULL_SEGNO;
if (!sync) {
if (has_not_enough_free_secs(sbi, sec_freed, 0))
goto gc_more;
if (gc_type == FG_GC)
ret = write_checkpoint(sbi, &cpc);
}
stop:
mutex_unlock(&sbi->gc_mutex);
put_gc_inode(&gc_list);
if (sync)
ret = sec_freed ? 0 : -EAGAIN;
return ret;
}
void build_gc_manager(struct f2fs_sb_info *sbi)
{
DIRTY_I(sbi)->v_ops = &default_v_ops;
}
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