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-rw-r--r--fs/f2fs/gc.c716
1 files changed, 716 insertions, 0 deletions
diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
new file mode 100644
index 00000000000..c386910dacc
--- /dev/null
+++ b/fs/f2fs/gc.c
@@ -0,0 +1,716 @@
+/*
+ * 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/proc_fs.h>
+#include <linux/init.h>
+#include <linux/f2fs_fs.h>
+#include <linux/kthread.h>
+#include <linux/delay.h>
+#include <linux/freezer.h>
+#include <linux/blkdev.h>
+
+#include "f2fs.h"
+#include "node.h"
+#include "segment.h"
+#include "gc.h"
+
+static struct kmem_cache *winode_slab;
+
+static int gc_thread_func(void *data)
+{
+ struct f2fs_sb_info *sbi = data;
+ wait_queue_head_t *wq = &sbi->gc_thread->gc_wait_queue_head;
+ long wait_ms;
+
+ wait_ms = GC_THREAD_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;
+
+ f2fs_balance_fs(sbi);
+
+ if (!test_opt(sbi, BG_GC))
+ continue;
+
+ /*
+ * [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 too much 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)) {
+ wait_ms = increase_sleep_time(wait_ms);
+ mutex_unlock(&sbi->gc_mutex);
+ continue;
+ }
+
+ if (has_enough_invalid_blocks(sbi))
+ wait_ms = decrease_sleep_time(wait_ms);
+ else
+ wait_ms = increase_sleep_time(wait_ms);
+
+ sbi->bg_gc++;
+
+ if (f2fs_gc(sbi) == GC_NONE)
+ wait_ms = GC_THREAD_NOGC_SLEEP_TIME;
+ else if (wait_ms == GC_THREAD_NOGC_SLEEP_TIME)
+ wait_ms = GC_THREAD_MAX_SLEEP_TIME;
+
+ } while (!kthread_should_stop());
+ return 0;
+}
+
+int start_gc_thread(struct f2fs_sb_info *sbi)
+{
+ struct f2fs_gc_kthread *gc_th;
+
+ gc_th = kmalloc(sizeof(struct f2fs_gc_kthread), GFP_KERNEL);
+ if (!gc_th)
+ return -ENOMEM;
+
+ 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,
+ GC_THREAD_NAME);
+ if (IS_ERR(gc_th->f2fs_gc_task)) {
+ kfree(gc_th);
+ return -ENOMEM;
+ }
+ return 0;
+}
+
+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(int gc_type)
+{
+ return (gc_type == BG_GC) ? GC_CB : GC_GREEDY;
+}
+
+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) {
+ p->gc_mode = GC_GREEDY;
+ p->dirty_segmap = dirty_i->dirty_segmap[type];
+ p->ofs_unit = 1;
+ } else {
+ p->gc_mode = select_gc_type(gc_type);
+ p->dirty_segmap = dirty_i->dirty_segmap[DIRTY];
+ p->ofs_unit = sbi->segs_per_sec;
+ }
+ p->offset = sbi->last_victim[p->gc_mode];
+}
+
+static unsigned int get_max_cost(struct f2fs_sb_info *sbi,
+ struct victim_sel_policy *p)
+{
+ if (p->gc_mode == GC_GREEDY)
+ return (1 << sbi->log_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 segno;
+
+ /*
+ * 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.
+ */
+ segno = find_next_bit(dirty_i->victim_segmap[BG_GC],
+ TOTAL_SEGS(sbi), 0);
+ if (segno < TOTAL_SEGS(sbi)) {
+ clear_bit(segno, dirty_i->victim_segmap[BG_GC]);
+ return segno;
+ }
+ 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 is changed by 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 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);
+}
+
+/*
+ * This function is called from two pathes.
+ * 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 segno;
+ int nsearched = 0;
+
+ 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);
+
+ mutex_lock(&dirty_i->seglist_lock);
+
+ 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;
+
+ segno = find_next_bit(p.dirty_segmap,
+ TOTAL_SEGS(sbi), p.offset);
+ if (segno >= TOTAL_SEGS(sbi)) {
+ if (sbi->last_victim[p.gc_mode]) {
+ sbi->last_victim[p.gc_mode] = 0;
+ p.offset = 0;
+ continue;
+ }
+ break;
+ }
+ p.offset = ((segno / p.ofs_unit) * p.ofs_unit) + p.ofs_unit;
+
+ if (test_bit(segno, dirty_i->victim_segmap[FG_GC]))
+ continue;
+ if (gc_type == BG_GC &&
+ test_bit(segno, dirty_i->victim_segmap[BG_GC]))
+ continue;
+ if (IS_CURSEC(sbi, GET_SECNO(sbi, segno)))
+ continue;
+
+ cost = get_gc_cost(sbi, segno, &p);
+
+ if (p.min_cost > cost) {
+ p.min_segno = segno;
+ p.min_cost = cost;
+ }
+
+ if (cost == get_max_cost(sbi, &p))
+ continue;
+
+ if (nsearched++ >= MAX_VICTIM_SEARCH) {
+ sbi->last_victim[p.gc_mode] = segno;
+ break;
+ }
+ }
+got_it:
+ if (p.min_segno != NULL_SEGNO) {
+ *result = (p.min_segno / p.ofs_unit) * p.ofs_unit;
+ if (p.alloc_mode == LFS) {
+ int i;
+ for (i = 0; i < p.ofs_unit; i++)
+ set_bit(*result + i,
+ dirty_i->victim_segmap[gc_type]);
+ }
+ }
+ 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(nid_t ino, struct list_head *ilist)
+{
+ struct list_head *this;
+ struct inode_entry *ie;
+
+ list_for_each(this, ilist) {
+ ie = list_entry(this, struct inode_entry, list);
+ if (ie->inode->i_ino == ino)
+ return ie->inode;
+ }
+ return NULL;
+}
+
+static void add_gc_inode(struct inode *inode, struct list_head *ilist)
+{
+ struct list_head *this;
+ struct inode_entry *new_ie, *ie;
+
+ list_for_each(this, ilist) {
+ ie = list_entry(this, struct inode_entry, list);
+ if (ie->inode == inode) {
+ iput(inode);
+ return;
+ }
+ }
+repeat:
+ new_ie = kmem_cache_alloc(winode_slab, GFP_NOFS);
+ if (!new_ie) {
+ cond_resched();
+ goto repeat;
+ }
+ new_ie->inode = inode;
+ list_add_tail(&new_ie->list, ilist);
+}
+
+static void put_gc_inode(struct list_head *ilist)
+{
+ struct inode_entry *ie, *next_ie;
+ list_for_each_entry_safe(ie, next_ie, ilist, list) {
+ iput(ie->inode);
+ list_del(&ie->list);
+ kmem_cache_free(winode_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 ? GC_OK : GC_NEXT;
+}
+
+/*
+ * 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 int gc_node_segment(struct f2fs_sb_info *sbi,
+ struct f2fs_summary *sum, unsigned int segno, int gc_type)
+{
+ bool initial = true;
+ struct f2fs_summary *entry;
+ int off;
+
+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;
+ int err;
+
+ /*
+ * It makes sure that free segments are able to write
+ * all the dirty node pages before CP after this CP.
+ * So let's check the space of dirty node pages.
+ */
+ if (should_do_checkpoint(sbi)) {
+ mutex_lock(&sbi->cp_mutex);
+ block_operations(sbi);
+ return GC_BLOCKED;
+ }
+
+ err = check_valid_map(sbi, segno, off);
+ if (err == GC_NEXT)
+ continue;
+
+ if (initial) {
+ ra_node_page(sbi, nid);
+ continue;
+ }
+ node_page = get_node_page(sbi, nid);
+ if (IS_ERR(node_page))
+ continue;
+
+ /* set page dirty and write it */
+ if (!PageWriteback(node_page))
+ set_page_dirty(node_page);
+ f2fs_put_page(node_page, 1);
+ stat_inc_node_blk_count(sbi, 1);
+ }
+ if (initial) {
+ initial = false;
+ goto next_step;
+ }
+
+ if (gc_type == FG_GC) {
+ struct writeback_control wbc = {
+ .sync_mode = WB_SYNC_ALL,
+ .nr_to_write = LONG_MAX,
+ .for_reclaim = 0,
+ };
+ sync_node_pages(sbi, 0, &wbc);
+ }
+ return GC_DONE;
+}
+
+/*
+ * 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)
+{
+ 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;
+}
+
+static int check_dnode(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 GC_NEXT;
+
+ get_node_info(sbi, nid, dni);
+
+ if (sum->version != dni->version) {
+ f2fs_put_page(node_page, 1);
+ return GC_NEXT;
+ }
+
+ *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 GC_NEXT;
+ return GC_OK;
+}
+
+static void move_data_page(struct inode *inode, struct page *page, int gc_type)
+{
+ if (page->mapping != inode->i_mapping)
+ goto out;
+
+ if (inode != page->mapping->host)
+ goto out;
+
+ if (PageWriteback(page))
+ goto out;
+
+ if (gc_type == BG_GC) {
+ set_page_dirty(page);
+ set_cold_data(page);
+ } else {
+ struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
+ mutex_lock_op(sbi, DATA_WRITE);
+ if (clear_page_dirty_for_io(page) &&
+ S_ISDIR(inode->i_mode)) {
+ dec_page_count(sbi, F2FS_DIRTY_DENTS);
+ inode_dec_dirty_dents(inode);
+ }
+ set_cold_data(page);
+ do_write_data_page(page);
+ mutex_unlock_op(sbi, DATA_WRITE);
+ 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 int gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
+ struct list_head *ilist, unsigned int segno, int gc_type)
+{
+ struct super_block *sb = sbi->sb;
+ struct f2fs_summary *entry;
+ block_t start_addr;
+ int err, 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;
+
+ /*
+ * It makes sure that free segments are able to write
+ * all the dirty node pages before CP after this CP.
+ * So let's check the space of dirty node pages.
+ */
+ if (should_do_checkpoint(sbi)) {
+ mutex_lock(&sbi->cp_mutex);
+ block_operations(sbi);
+ err = GC_BLOCKED;
+ goto stop;
+ }
+
+ err = check_valid_map(sbi, segno, off);
+ if (err == GC_NEXT)
+ continue;
+
+ if (phase == 0) {
+ ra_node_page(sbi, le32_to_cpu(entry->nid));
+ continue;
+ }
+
+ /* Get an inode by ino with checking validity */
+ err = check_dnode(sbi, entry, &dni, start_addr + off, &nofs);
+ if (err == GC_NEXT)
+ continue;
+
+ if (phase == 1) {
+ ra_node_page(sbi, dni.ino);
+ continue;
+ }
+
+ start_bidx = start_bidx_of_node(nofs);
+ ofs_in_node = le16_to_cpu(entry->ofs_in_node);
+
+ if (phase == 2) {
+ inode = f2fs_iget_nowait(sb, dni.ino);
+ if (IS_ERR(inode))
+ continue;
+
+ data_page = find_data_page(inode,
+ start_bidx + ofs_in_node);
+ if (IS_ERR(data_page))
+ goto next_iput;
+
+ f2fs_put_page(data_page, 0);
+ add_gc_inode(inode, ilist);
+ } else {
+ inode = find_gc_inode(dni.ino, ilist);
+ if (inode) {
+ data_page = get_lock_data_page(inode,
+ start_bidx + ofs_in_node);
+ if (IS_ERR(data_page))
+ continue;
+ move_data_page(inode, data_page, gc_type);
+ stat_inc_data_blk_count(sbi, 1);
+ }
+ }
+ continue;
+next_iput:
+ iput(inode);
+ }
+ if (++phase < 4)
+ goto next_step;
+ err = GC_DONE;
+stop:
+ if (gc_type == FG_GC)
+ f2fs_submit_bio(sbi, DATA, true);
+ return err;
+}
+
+static int __get_victim(struct f2fs_sb_info *sbi, unsigned int *victim,
+ int gc_type, int 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, type, LFS);
+ mutex_unlock(&sit_i->sentry_lock);
+ return ret;
+}
+
+static int do_garbage_collect(struct f2fs_sb_info *sbi, unsigned int segno,
+ struct list_head *ilist, int gc_type)
+{
+ struct page *sum_page;
+ struct f2fs_summary_block *sum;
+ int ret = GC_DONE;
+
+ /* read segment summary of victim */
+ sum_page = get_sum_page(sbi, segno);
+ if (IS_ERR(sum_page))
+ return GC_ERROR;
+
+ /*
+ * CP needs to lock sum_page. In this time, we don't need
+ * to lock this page, because this summary page is not gone anywhere.
+ * Also, this page is not gonna be updated before GC is done.
+ */
+ unlock_page(sum_page);
+ sum = page_address(sum_page);
+
+ switch (GET_SUM_TYPE((&sum->footer))) {
+ case SUM_TYPE_NODE:
+ ret = gc_node_segment(sbi, sum->entries, segno, gc_type);
+ break;
+ case SUM_TYPE_DATA:
+ ret = gc_data_segment(sbi, sum->entries, ilist, segno, gc_type);
+ break;
+ }
+ stat_inc_seg_count(sbi, GET_SUM_TYPE((&sum->footer)));
+ stat_inc_call_count(sbi->stat_info);
+
+ f2fs_put_page(sum_page, 0);
+ return ret;
+}
+
+int f2fs_gc(struct f2fs_sb_info *sbi)
+{
+ struct list_head ilist;
+ unsigned int segno, i;
+ int gc_type = BG_GC;
+ int gc_status = GC_NONE;
+
+ INIT_LIST_HEAD(&ilist);
+gc_more:
+ if (!(sbi->sb->s_flags & MS_ACTIVE))
+ goto stop;
+
+ if (has_not_enough_free_secs(sbi))
+ gc_type = FG_GC;
+
+ if (!__get_victim(sbi, &segno, gc_type, NO_CHECK_TYPE))
+ goto stop;
+
+ for (i = 0; i < sbi->segs_per_sec; i++) {
+ /*
+ * do_garbage_collect will give us three gc_status:
+ * GC_ERROR, GC_DONE, and GC_BLOCKED.
+ * If GC is finished uncleanly, we have to return
+ * the victim to dirty segment list.
+ */
+ gc_status = do_garbage_collect(sbi, segno + i, &ilist, gc_type);
+ if (gc_status != GC_DONE)
+ break;
+ }
+ if (has_not_enough_free_secs(sbi)) {
+ write_checkpoint(sbi, (gc_status == GC_BLOCKED), false);
+ if (has_not_enough_free_secs(sbi))
+ goto gc_more;
+ }
+stop:
+ mutex_unlock(&sbi->gc_mutex);
+
+ put_gc_inode(&ilist);
+ return gc_status;
+}
+
+void build_gc_manager(struct f2fs_sb_info *sbi)
+{
+ DIRTY_I(sbi)->v_ops = &default_v_ops;
+}
+
+int __init create_gc_caches(void)
+{
+ winode_slab = f2fs_kmem_cache_create("f2fs_gc_inodes",
+ sizeof(struct inode_entry), NULL);
+ if (!winode_slab)
+ return -ENOMEM;
+ return 0;
+}
+
+void destroy_gc_caches(void)
+{
+ kmem_cache_destroy(winode_slab);
+}