f2fs: refactor extent_cache to support for read and more

This patch prepares extent_cache to be ready for addition.

Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/data.c

@@ -1126,7 +1126,7 @@ void f2fs_update_data_blkaddr(struct dnode_of_data *dn, block_t blkaddr)
 {
 	dn->data_blkaddr = blkaddr;
 	f2fs_set_data_blkaddr(dn);
-	f2fs_update_extent_cache(dn);
+	f2fs_update_read_extent_cache(dn);
 }
 
 /* dn->ofs_in_node will be returned with up-to-date last block pointer */
@@ -1195,7 +1195,7 @@ int f2fs_get_block(struct dnode_of_data *dn, pgoff_t index)
 	struct extent_info ei = {0, };
 	struct inode *inode = dn->inode;
 
-	if (f2fs_lookup_extent_cache(inode, index, &ei)) {
+	if (f2fs_lookup_read_extent_cache(inode, index, &ei)) {
 		dn->data_blkaddr = ei.blk + index - ei.fofs;
 		return 0;
 	}
@@ -1217,7 +1217,7 @@ struct page *f2fs_get_read_data_page(struct inode *inode, pgoff_t index,
 	if (!page)
 		return ERR_PTR(-ENOMEM);
 
-	if (f2fs_lookup_extent_cache(inode, index, &ei)) {
+	if (f2fs_lookup_read_extent_cache(inode, index, &ei)) {
 		dn.data_blkaddr = ei.blk + index - ei.fofs;
 		if (!f2fs_is_valid_blkaddr(F2FS_I_SB(inode), dn.data_blkaddr,
 						DATA_GENERIC_ENHANCE_READ)) {
@@ -1485,7 +1485,7 @@ int f2fs_map_blocks(struct inode *inode, struct f2fs_map_blocks *map,
 	pgofs =	(pgoff_t)map->m_lblk;
 	end = pgofs + maxblocks;
 
-	if (!create && f2fs_lookup_extent_cache(inode, pgofs, &ei)) {
+	if (!create && f2fs_lookup_read_extent_cache(inode, pgofs, &ei)) {
 		if (f2fs_lfs_mode(sbi) && flag == F2FS_GET_BLOCK_DIO &&
 							map->m_may_create)
 			goto next_dnode;
@@ -1695,7 +1695,7 @@ skip:
 		if (map->m_flags & F2FS_MAP_MAPPED) {
 			unsigned int ofs = start_pgofs - map->m_lblk;
 
-			f2fs_update_extent_cache_range(&dn,
+			f2fs_update_read_extent_cache_range(&dn,
 				start_pgofs, map->m_pblk + ofs,
 				map->m_len - ofs);
 		}
@@ -1740,7 +1740,7 @@ sync_out:
 		if (map->m_flags & F2FS_MAP_MAPPED) {
 			unsigned int ofs = start_pgofs - map->m_lblk;
 
-			f2fs_update_extent_cache_range(&dn,
+			f2fs_update_read_extent_cache_range(&dn,
 				start_pgofs, map->m_pblk + ofs,
 				map->m_len - ofs);
 		}
@@ -2201,7 +2201,7 @@ int f2fs_read_multi_pages(struct compress_ctx *cc, struct bio **bio_ret,
 	if (f2fs_cluster_is_empty(cc))
 		goto out;
 
-	if (f2fs_lookup_extent_cache(inode, start_idx, &ei))
+	if (f2fs_lookup_read_extent_cache(inode, start_idx, &ei))
 		from_dnode = false;
 
 	if (!from_dnode)
@@ -2635,7 +2635,7 @@ int f2fs_do_write_data_page(struct f2fs_io_info *fio)
 		set_new_dnode(&dn, inode, NULL, NULL, 0);
 
 	if (need_inplace_update(fio) &&
-			f2fs_lookup_extent_cache(inode, page->index, &ei)) {
+	    f2fs_lookup_read_extent_cache(inode, page->index, &ei)) {
 		fio->old_blkaddr = ei.blk + page->index - ei.fofs;
 
 		if (!f2fs_is_valid_blkaddr(fio->sbi, fio->old_blkaddr,
@@ -3359,7 +3359,7 @@ restart:
 	} else if (locked) {
 		err = f2fs_get_block(&dn, index);
 	} else {
-		if (f2fs_lookup_extent_cache(inode, index, &ei)) {
+		if (f2fs_lookup_read_extent_cache(inode, index, &ei)) {
 			dn.data_blkaddr = ei.blk + index - ei.fofs;
 		} else {
 			/* hole case */
@@ -3400,7 +3400,7 @@ static int __find_data_block(struct inode *inode, pgoff_t index,
 
 	set_new_dnode(&dn, inode, ipage, ipage, 0);
 
-	if (f2fs_lookup_extent_cache(inode, index, &ei)) {
+	if (f2fs_lookup_read_extent_cache(inode, index, &ei)) {
 		dn.data_blkaddr = ei.blk + index - ei.fofs;
 	} else {
 		/* hole case */

fs/f2fs/debug.c

@@ -72,15 +72,23 @@ static void update_general_status(struct f2fs_sb_info *sbi)
 	si->main_area_zones = si->main_area_sections /
 				le32_to_cpu(raw_super->secs_per_zone);
 
-	/* validation check of the segment numbers */
+	/* general extent cache stats */
+	for (i = 0; i < NR_EXTENT_CACHES; i++) {
+		struct extent_tree_info *eti = &sbi->extent_tree[i];
+
+		si->hit_cached[i] = atomic64_read(&sbi->read_hit_cached[i]);
+		si->hit_rbtree[i] = atomic64_read(&sbi->read_hit_rbtree[i]);
+		si->total_ext[i] = atomic64_read(&sbi->total_hit_ext[i]);
+		si->hit_total[i] = si->hit_cached[i] + si->hit_rbtree[i];
+		si->ext_tree[i] = atomic_read(&eti->total_ext_tree);
+		si->zombie_tree[i] = atomic_read(&eti->total_zombie_tree);
+		si->ext_node[i] = atomic_read(&eti->total_ext_node);
+	}
+	/* read extent_cache only */
 	si->hit_largest = atomic64_read(&sbi->read_hit_largest);
-	si->hit_cached = atomic64_read(&sbi->read_hit_cached);
+	si->hit_total[EX_READ] += si->hit_largest;
-	si->hit_rbtree = atomic64_read(&sbi->read_hit_rbtree);
+
-	si->hit_total = si->hit_largest + si->hit_cached + si->hit_rbtree;
+	/* validation check of the segment numbers */
-	si->total_ext = atomic64_read(&sbi->total_hit_ext);
-	si->ext_tree = atomic_read(&sbi->total_ext_tree);
-	si->zombie_tree = atomic_read(&sbi->total_zombie_tree);
-	si->ext_node = atomic_read(&sbi->total_ext_node);
 	si->ndirty_node = get_pages(sbi, F2FS_DIRTY_NODES);
 	si->ndirty_dent = get_pages(sbi, F2FS_DIRTY_DENTS);
 	si->ndirty_meta = get_pages(sbi, F2FS_DIRTY_META);
@@ -294,10 +302,16 @@ get_cache:
 				sizeof(struct nat_entry_set);
 	for (i = 0; i < MAX_INO_ENTRY; i++)
 		si->cache_mem += sbi->im[i].ino_num * sizeof(struct ino_entry);
-	si->cache_mem += atomic_read(&sbi->total_ext_tree) *
+
+	for (i = 0; i < NR_EXTENT_CACHES; i++) {
+		struct extent_tree_info *eti = &sbi->extent_tree[i];
+
+		si->ext_mem[i] = atomic_read(&eti->total_ext_tree) *
 						sizeof(struct extent_tree);
-	si->cache_mem += atomic_read(&sbi->total_ext_node) *
+		si->ext_mem[i] += atomic_read(&eti->total_ext_node) *
 						sizeof(struct extent_node);
+		si->cache_mem += si->ext_mem[i];
+	}
 
 	si->page_mem = 0;
 	if (sbi->node_inode) {
@@ -490,16 +504,18 @@ static int stat_show(struct seq_file *s, void *v)
 				si->bg_node_blks);
 		seq_printf(s, "BG skip : IO: %u, Other: %u\n",
 				si->io_skip_bggc, si->other_skip_bggc);
-		seq_puts(s, "\nExtent Cache:\n");
+		seq_puts(s, "\nExtent Cache (Read):\n");
 		seq_printf(s, "  - Hit Count: L1-1:%llu L1-2:%llu L2:%llu\n",
-				si->hit_largest, si->hit_cached,
+				si->hit_largest, si->hit_cached[EX_READ],
-				si->hit_rbtree);
+				si->hit_rbtree[EX_READ]);
 		seq_printf(s, "  - Hit Ratio: %llu%% (%llu / %llu)\n",
-				!si->total_ext ? 0 :
+				!si->total_ext[EX_READ] ? 0 :
-				div64_u64(si->hit_total * 100, si->total_ext),
+				div64_u64(si->hit_total[EX_READ] * 100,
-				si->hit_total, si->total_ext);
+				si->total_ext[EX_READ]),
+				si->hit_total[EX_READ], si->total_ext[EX_READ]);
 		seq_printf(s, "  - Inner Struct Count: tree: %d(%d), node: %d\n",
-				si->ext_tree, si->zombie_tree, si->ext_node);
+				si->ext_tree[EX_READ], si->zombie_tree[EX_READ],
+				si->ext_node[EX_READ]);
 		seq_puts(s, "\nBalancing F2FS Async:\n");
 		seq_printf(s, "  - DIO (R: %4d, W: %4d)\n",
 			   si->nr_dio_read, si->nr_dio_write);
@@ -566,8 +582,10 @@ static int stat_show(struct seq_file *s, void *v)
 			(si->base_mem + si->cache_mem + si->page_mem) >> 10);
 		seq_printf(s, "  - static: %llu KB\n",
 				si->base_mem >> 10);
-		seq_printf(s, "  - cached: %llu KB\n",
+		seq_printf(s, "  - cached all: %llu KB\n",
 				si->cache_mem >> 10);
+		seq_printf(s, "  - read extent cache: %llu KB\n",
+				si->ext_mem[EX_READ] >> 10);
 		seq_printf(s, "  - paged : %llu KB\n",
 				si->page_mem >> 10);
 	}
@@ -600,10 +618,15 @@ int f2fs_build_stats(struct f2fs_sb_info *sbi)
 	si->sbi = sbi;
 	sbi->stat_info = si;
 
-	atomic64_set(&sbi->total_hit_ext, 0);
+	/* general extent cache stats */
-	atomic64_set(&sbi->read_hit_rbtree, 0);
+	for (i = 0; i < NR_EXTENT_CACHES; i++) {
+		atomic64_set(&sbi->total_hit_ext[i], 0);
+		atomic64_set(&sbi->read_hit_rbtree[i], 0);
+		atomic64_set(&sbi->read_hit_cached[i], 0);
+	}
+
+	/* read extent_cache only */
 	atomic64_set(&sbi->read_hit_largest, 0);
-	atomic64_set(&sbi->read_hit_cached, 0);
 
 	atomic_set(&sbi->inline_xattr, 0);
 	atomic_set(&sbi->inline_inode, 0);

fs/f2fs/extent_cache.c

@@ -17,21 +17,37 @@
 
 static void __set_extent_info(struct extent_info *ei,
 				unsigned int fofs, unsigned int len,
-				block_t blk, bool keep_clen)
+				block_t blk, bool keep_clen,
+				enum extent_type type)
 {
 	ei->fofs = fofs;
-	ei->blk = blk;
 	ei->len = len;
 
-	if (keep_clen)
+	if (type == EX_READ) {
-		return;
+		ei->blk = blk;
-
+		if (keep_clen)
+			return;
 #ifdef CONFIG_F2FS_FS_COMPRESSION
-	ei->c_len = 0;
+		ei->c_len = 0;
 #endif
+	}
 }
 
-static bool f2fs_may_extent_tree(struct inode *inode)
+static bool __may_read_extent_tree(struct inode *inode)
+{
+	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
+
+	if (!test_opt(sbi, READ_EXTENT_CACHE))
+		return false;
+	if (is_inode_flag_set(inode, FI_NO_EXTENT))
+		return false;
+	if (is_inode_flag_set(inode, FI_COMPRESSED_FILE) &&
+			 !f2fs_sb_has_readonly(sbi))
+		return false;
+	return S_ISREG(inode->i_mode);
+}
+
+static bool __may_extent_tree(struct inode *inode, enum extent_type type)
 {
 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
 
@@ -42,18 +58,16 @@ static bool f2fs_may_extent_tree(struct inode *inode)
 	if (list_empty(&sbi->s_list))
 		return false;
 
-	if (!test_opt(sbi, READ_EXTENT_CACHE) ||
+	if (type == EX_READ)
-			is_inode_flag_set(inode, FI_NO_EXTENT) ||
+		return __may_read_extent_tree(inode);
-			(is_inode_flag_set(inode, FI_COMPRESSED_FILE) &&
+	return false;
-			 !f2fs_sb_has_readonly(sbi)))
-		return false;
-
-	return S_ISREG(inode->i_mode);
 }
 
 static void __try_update_largest_extent(struct extent_tree *et,
 						struct extent_node *en)
 {
+	if (et->type != EX_READ)
+		return;
 	if (en->ei.len <= et->largest.len)
 		return;
 
@@ -62,28 +76,31 @@ static void __try_update_largest_extent(struct extent_tree *et,
 }
 
 static bool __is_extent_mergeable(struct extent_info *back,
-				struct extent_info *front)
+		struct extent_info *front, enum extent_type type)
 {
+	if (type == EX_READ) {
 #ifdef CONFIG_F2FS_FS_COMPRESSION
-	if (back->c_len && back->len != back->c_len)
+		if (back->c_len && back->len != back->c_len)
-		return false;
+			return false;
-	if (front->c_len && front->len != front->c_len)
+		if (front->c_len && front->len != front->c_len)
-		return false;
+			return false;
 #endif
-	return (back->fofs + back->len == front->fofs &&
+		return (back->fofs + back->len == front->fofs &&
-			back->blk + back->len == front->blk);
+				back->blk + back->len == front->blk);
+	}
+	return false;
 }
 
 static bool __is_back_mergeable(struct extent_info *cur,
-				struct extent_info *back)
+		struct extent_info *back, enum extent_type type)
 {
-	return __is_extent_mergeable(back, cur);
+	return __is_extent_mergeable(back, cur, type);
 }
 
 static bool __is_front_mergeable(struct extent_info *cur,
-				struct extent_info *front)
+		struct extent_info *front, enum extent_type type)
 {
-	return __is_extent_mergeable(cur, front);
+	return __is_extent_mergeable(cur, front, type);
 }
 
 static struct rb_entry *__lookup_rb_tree_fast(struct rb_entry *cached_re,
@@ -308,6 +325,7 @@ static struct extent_node *__attach_extent_node(struct f2fs_sb_info *sbi,
 				struct rb_node *parent, struct rb_node **p,
 				bool leftmost)
 {
+	struct extent_tree_info *eti = &sbi->extent_tree[et->type];
 	struct extent_node *en;
 
 	en = f2fs_kmem_cache_alloc(extent_node_slab, GFP_ATOMIC, false, sbi);
@@ -321,16 +339,18 @@ static struct extent_node *__attach_extent_node(struct f2fs_sb_info *sbi,
 	rb_link_node(&en->rb_node, parent, p);
 	rb_insert_color_cached(&en->rb_node, &et->root, leftmost);
 	atomic_inc(&et->node_cnt);
-	atomic_inc(&sbi->total_ext_node);
+	atomic_inc(&eti->total_ext_node);
 	return en;
 }
 
 static void __detach_extent_node(struct f2fs_sb_info *sbi,
 				struct extent_tree *et, struct extent_node *en)
 {
+	struct extent_tree_info *eti = &sbi->extent_tree[et->type];
+
 	rb_erase_cached(&en->rb_node, &et->root);
 	atomic_dec(&et->node_cnt);
-	atomic_dec(&sbi->total_ext_node);
+	atomic_dec(&eti->total_ext_node);
 
 	if (et->cached_en == en)
 		et->cached_en = NULL;
@@ -346,42 +366,47 @@ static void __detach_extent_node(struct f2fs_sb_info *sbi,
 static void __release_extent_node(struct f2fs_sb_info *sbi,
 			struct extent_tree *et, struct extent_node *en)
 {
-	spin_lock(&sbi->extent_lock);
+	struct extent_tree_info *eti = &sbi->extent_tree[et->type];
+
+	spin_lock(&eti->extent_lock);
 	f2fs_bug_on(sbi, list_empty(&en->list));
 	list_del_init(&en->list);
-	spin_unlock(&sbi->extent_lock);
+	spin_unlock(&eti->extent_lock);
 
 	__detach_extent_node(sbi, et, en);
 }
 
-static struct extent_tree *__grab_extent_tree(struct inode *inode)
+static struct extent_tree *__grab_extent_tree(struct inode *inode,
+						enum extent_type type)
 {
 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
+	struct extent_tree_info *eti = &sbi->extent_tree[type];
 	struct extent_tree *et;
 	nid_t ino = inode->i_ino;
 
-	mutex_lock(&sbi->extent_tree_lock);
+	mutex_lock(&eti->extent_tree_lock);
-	et = radix_tree_lookup(&sbi->extent_tree_root, ino);
+	et = radix_tree_lookup(&eti->extent_tree_root, ino);
 	if (!et) {
 		et = f2fs_kmem_cache_alloc(extent_tree_slab,
 					GFP_NOFS, true, NULL);
-		f2fs_radix_tree_insert(&sbi->extent_tree_root, ino, et);
+		f2fs_radix_tree_insert(&eti->extent_tree_root, ino, et);
 		memset(et, 0, sizeof(struct extent_tree));
 		et->ino = ino;
+		et->type = type;
 		et->root = RB_ROOT_CACHED;
 		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);
+		atomic_inc(&eti->total_ext_tree);
 	} else {
-		atomic_dec(&sbi->total_zombie_tree);
+		atomic_dec(&eti->total_zombie_tree);
 		list_del_init(&et->list);
 	}
-	mutex_unlock(&sbi->extent_tree_lock);
+	mutex_unlock(&eti->extent_tree_lock);
 
 	/* never died until evict_inode */
-	F2FS_I(inode)->extent_tree = et;
+	F2FS_I(inode)->extent_tree[type] = et;
 
 	return et;
 }
@@ -415,35 +440,38 @@ static void __drop_largest_extent(struct extent_tree *et,
 }
 
 /* return true, if inode page is changed */
-static void __f2fs_init_extent_tree(struct inode *inode, struct page *ipage)
+static void __f2fs_init_extent_tree(struct inode *inode, struct page *ipage,
+							enum extent_type type)
 {
 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
+	struct extent_tree_info *eti = &sbi->extent_tree[type];
 	struct f2fs_extent *i_ext = ipage ? &F2FS_INODE(ipage)->i_ext : NULL;
 	struct extent_tree *et;
 	struct extent_node *en;
 	struct extent_info ei;
 
-	if (!f2fs_may_extent_tree(inode)) {
+	if (!__may_extent_tree(inode, type)) {
-		/* drop largest extent */
+		/* drop largest read extent */
-		if (i_ext && i_ext->len) {
+		if (type == EX_READ && i_ext && i_ext->len) {
 			f2fs_wait_on_page_writeback(ipage, NODE, true, true);
 			i_ext->len = 0;
 			set_page_dirty(ipage);
-			return;
 		}
-		return;
+		goto out;
 	}
 
-	et = __grab_extent_tree(inode);
+	et = __grab_extent_tree(inode, type);
 
 	if (!i_ext || !i_ext->len)
-		return;
+		goto out;
+
+	BUG_ON(type != EX_READ);
 
 	get_read_extent_info(&ei, i_ext);
 
 	write_lock(&et->lock);
 	if (atomic_read(&et->node_cnt))
-		goto out;
+		goto unlock_out;
 
 	en = __attach_extent_node(sbi, et, &ei, NULL,
 				&et->root.rb_root.rb_node, true);
@@ -451,37 +479,40 @@ static void __f2fs_init_extent_tree(struct inode *inode, struct page *ipage)
 		et->largest = en->ei;
 		et->cached_en = en;
 
-		spin_lock(&sbi->extent_lock);
+		spin_lock(&eti->extent_lock);
-		list_add_tail(&en->list, &sbi->extent_list);
+		list_add_tail(&en->list, &eti->extent_list);
-		spin_unlock(&sbi->extent_lock);
+		spin_unlock(&eti->extent_lock);
 	}
-out:
+unlock_out:
 	write_unlock(&et->lock);
+out:
+	if (type == EX_READ && !F2FS_I(inode)->extent_tree[EX_READ])
+		set_inode_flag(inode, FI_NO_EXTENT);
 }
 
 void f2fs_init_extent_tree(struct inode *inode, struct page *ipage)
 {
-	__f2fs_init_extent_tree(inode, ipage);
+	/* initialize read cache */
-
+	__f2fs_init_extent_tree(inode, ipage, EX_READ);
-	if (!F2FS_I(inode)->extent_tree)
-		set_inode_flag(inode, FI_NO_EXTENT);
 }
 
-static bool f2fs_lookup_extent_tree(struct inode *inode, pgoff_t pgofs,
+static bool __lookup_extent_tree(struct inode *inode, pgoff_t pgofs,
-							struct extent_info *ei)
+			struct extent_info *ei, enum extent_type type)
 {
 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
-	struct extent_tree *et = F2FS_I(inode)->extent_tree;
+	struct extent_tree_info *eti = &sbi->extent_tree[type];
+	struct extent_tree *et = F2FS_I(inode)->extent_tree[type];
 	struct extent_node *en;
 	bool ret = false;
 
 	f2fs_bug_on(sbi, !et);
 
-	trace_f2fs_lookup_extent_tree_start(inode, pgofs);
+	trace_f2fs_lookup_extent_tree_start(inode, pgofs, type);
 
 	read_lock(&et->lock);
 
-	if (et->largest.fofs <= pgofs &&
+	if (type == EX_READ &&
+			et->largest.fofs <= pgofs &&
 			et->largest.fofs + et->largest.len > pgofs) {
 		*ei = et->largest;
 		ret = true;
@@ -495,23 +526,24 @@ static bool f2fs_lookup_extent_tree(struct inode *inode, pgoff_t pgofs,
 		goto out;
 
 	if (en == et->cached_en)
-		stat_inc_cached_node_hit(sbi);
+		stat_inc_cached_node_hit(sbi, type);
 	else
-		stat_inc_rbtree_node_hit(sbi);
+		stat_inc_rbtree_node_hit(sbi, type);
 
 	*ei = en->ei;
-	spin_lock(&sbi->extent_lock);
+	spin_lock(&eti->extent_lock);
 	if (!list_empty(&en->list)) {
-		list_move_tail(&en->list, &sbi->extent_list);
+		list_move_tail(&en->list, &eti->extent_list);
 		et->cached_en = en;
 	}
-	spin_unlock(&sbi->extent_lock);
+	spin_unlock(&eti->extent_lock);
 	ret = true;
 out:
-	stat_inc_total_hit(sbi);
+	stat_inc_total_hit(sbi, type);
 	read_unlock(&et->lock);
 
-	trace_f2fs_lookup_extent_tree_end(inode, pgofs, ei);
+	if (type == EX_READ)
+		trace_f2fs_lookup_read_extent_tree_end(inode, pgofs, ei);
 	return ret;
 }
 
@@ -520,18 +552,20 @@ static struct extent_node *__try_merge_extent_node(struct f2fs_sb_info *sbi,
 				struct extent_node *prev_ex,
 				struct extent_node *next_ex)
 {
+	struct extent_tree_info *eti = &sbi->extent_tree[et->type];
 	struct extent_node *en = NULL;
 
-	if (prev_ex && __is_back_mergeable(ei, &prev_ex->ei)) {
+	if (prev_ex && __is_back_mergeable(ei, &prev_ex->ei, et->type)) {
 		prev_ex->ei.len += ei->len;
 		ei = &prev_ex->ei;
 		en = prev_ex;
 	}
 
-	if (next_ex && __is_front_mergeable(ei, &next_ex->ei)) {
+	if (next_ex && __is_front_mergeable(ei, &next_ex->ei, et->type)) {
 		next_ex->ei.fofs = ei->fofs;
-		next_ex->ei.blk = ei->blk;
 		next_ex->ei.len += ei->len;
+		if (et->type == EX_READ)
+			next_ex->ei.blk = ei->blk;
 		if (en)
 			__release_extent_node(sbi, et, prev_ex);
 
@@ -543,12 +577,12 @@ static struct extent_node *__try_merge_extent_node(struct f2fs_sb_info *sbi,
 
 	__try_update_largest_extent(et, en);
 
-	spin_lock(&sbi->extent_lock);
+	spin_lock(&eti->extent_lock);
 	if (!list_empty(&en->list)) {
-		list_move_tail(&en->list, &sbi->extent_list);
+		list_move_tail(&en->list, &eti->extent_list);
 		et->cached_en = en;
 	}
-	spin_unlock(&sbi->extent_lock);
+	spin_unlock(&eti->extent_lock);
 	return en;
 }
 
@@ -558,6 +592,7 @@ static struct extent_node *__insert_extent_tree(struct f2fs_sb_info *sbi,
 				struct rb_node *insert_parent,
 				bool leftmost)
 {
+	struct extent_tree_info *eti = &sbi->extent_tree[et->type];
 	struct rb_node **p;
 	struct rb_node *parent = NULL;
 	struct extent_node *en = NULL;
@@ -580,48 +615,51 @@ do_insert:
 	__try_update_largest_extent(et, en);
 
 	/* update in global extent list */
-	spin_lock(&sbi->extent_lock);
+	spin_lock(&eti->extent_lock);
-	list_add_tail(&en->list, &sbi->extent_list);
+	list_add_tail(&en->list, &eti->extent_list);
 	et->cached_en = en;
-	spin_unlock(&sbi->extent_lock);
+	spin_unlock(&eti->extent_lock);
 	return en;
 }
 
-static void f2fs_update_extent_tree_range(struct inode *inode,
+static void __update_extent_tree_range(struct inode *inode,
-				pgoff_t fofs, block_t blkaddr, unsigned int len)
+			struct extent_info *tei, enum extent_type type)
 {
 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
-	struct extent_tree *et = F2FS_I(inode)->extent_tree;
+	struct extent_tree *et = F2FS_I(inode)->extent_tree[type];
 	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 fofs = tei->fofs, len = tei->len;
 	unsigned int end = fofs + len;
-	unsigned int pos = (unsigned int)fofs;
 	bool updated = false;
 	bool leftmost = false;
 
 	if (!et)
 		return;
 
-	trace_f2fs_update_extent_tree_range(inode, fofs, blkaddr, len, 0);
+	if (type == EX_READ)
-
+		trace_f2fs_update_read_extent_tree_range(inode, fofs, len,
+						tei->blk, 0);
 	write_lock(&et->lock);
 
-	if (is_inode_flag_set(inode, FI_NO_EXTENT)) {
+	if (type == EX_READ) {
-		write_unlock(&et->lock);
+		if (is_inode_flag_set(inode, FI_NO_EXTENT)) {
-		return;
+			write_unlock(&et->lock);
+			return;
+		}
+
+		prev = et->largest;
+		dei.len = 0;
+
+		/*
+		 * drop largest extent before lookup, in case it's already
+		 * been shrunk from extent tree
+		 */
+		__drop_largest_extent(et, fofs, len);
 	}
 
-	prev = et->largest;
-	dei.len = 0;
-
-	/*
-	 * drop largest extent before lookup, in case it's already
-	 * been shrunk from extent tree
-	 */
-	__drop_largest_extent(et, fofs, len);
-
 	/* 1. lookup first extent node in range [fofs, fofs + len - 1] */
 	en = (struct extent_node *)f2fs_lookup_rb_tree_ret(&et->root,
 					(struct rb_entry *)et->cached_en, fofs,
@@ -641,26 +679,30 @@ static void f2fs_update_extent_tree_range(struct inode *inode,
 
 		dei = en->ei;
 		org_end = dei.fofs + dei.len;
-		f2fs_bug_on(sbi, pos >= org_end);
+		f2fs_bug_on(sbi, fofs >= org_end);
 
-		if (pos > dei.fofs && pos - dei.fofs >= F2FS_MIN_EXTENT_LEN) {
+		if (fofs > dei.fofs && (type != EX_READ ||
-			en->ei.len = pos - en->ei.fofs;
+				fofs - dei.fofs >= F2FS_MIN_EXTENT_LEN)) {
+			en->ei.len = fofs - en->ei.fofs;
 			prev_en = en;
 			parts = 1;
 		}
 
-		if (end < org_end && org_end - end >= F2FS_MIN_EXTENT_LEN) {
+		if (end < org_end && (type != EX_READ ||
+				org_end - end >= F2FS_MIN_EXTENT_LEN)) {
 			if (parts) {
 				__set_extent_info(&ei,
 					end, org_end - end,
-					end - dei.fofs + dei.blk, false);
+					end - dei.fofs + dei.blk, false,
+					type);
 				en1 = __insert_extent_tree(sbi, et, &ei,
 							NULL, NULL, true);
 				next_en = en1;
 			} else {
 				__set_extent_info(&en->ei,
 					end, en->ei.len - (end - dei.fofs),
-					en->ei.blk + (end - dei.fofs), true);
+					en->ei.blk + (end - dei.fofs), true,
+					type);
 				next_en = en;
 			}
 			parts++;
@@ -690,9 +732,11 @@ static void f2fs_update_extent_tree_range(struct inode *inode,
 		en = next_en;
 	}
 
-	/* 3. update extent in extent cache */
+	/* 3. update extent in read extent cache */
-	if (blkaddr) {
+	BUG_ON(type != EX_READ);
-		__set_extent_info(&ei, fofs, len, blkaddr, false);
+
+	if (tei->blk) {
+		__set_extent_info(&ei, fofs, len, tei->blk, false, EX_READ);
 		if (!__try_merge_extent_node(sbi, et, &ei, prev_en, next_en))
 			__insert_extent_tree(sbi, et, &ei,
 					insert_p, insert_parent, leftmost);
@@ -722,19 +766,20 @@ static void f2fs_update_extent_tree_range(struct inode *inode,
 }
 
 #ifdef CONFIG_F2FS_FS_COMPRESSION
-void f2fs_update_extent_tree_range_compressed(struct inode *inode,
+void f2fs_update_read_extent_tree_range_compressed(struct inode *inode,
 				pgoff_t fofs, block_t blkaddr, unsigned int llen,
 				unsigned int c_len)
 {
 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
-	struct extent_tree *et = F2FS_I(inode)->extent_tree;
+	struct extent_tree *et = F2FS_I(inode)->extent_tree[EX_READ];
 	struct extent_node *en = NULL;
 	struct extent_node *prev_en = NULL, *next_en = NULL;
 	struct extent_info ei;
 	struct rb_node **insert_p = NULL, *insert_parent = NULL;
 	bool leftmost = false;
 
-	trace_f2fs_update_extent_tree_range(inode, fofs, blkaddr, llen, c_len);
+	trace_f2fs_update_read_extent_tree_range(inode, fofs, llen,
+						blkaddr, c_len);
 
 	/* it is safe here to check FI_NO_EXTENT w/o et->lock in ro image */
 	if (is_inode_flag_set(inode, FI_NO_EXTENT))
@@ -751,7 +796,7 @@ void f2fs_update_extent_tree_range_compressed(struct inode *inode,
 	if (en)
 		goto unlock_out;
 
-	__set_extent_info(&ei, fofs, llen, blkaddr, true);
+	__set_extent_info(&ei, fofs, llen, blkaddr, true, EX_READ);
 	ei.c_len = c_len;
 
 	if (!__try_merge_extent_node(sbi, et, &ei, prev_en, next_en))
@@ -762,24 +807,43 @@ unlock_out:
 }
 #endif
 
-unsigned int f2fs_shrink_extent_tree(struct f2fs_sb_info *sbi, int nr_shrink)
+static void __update_extent_cache(struct dnode_of_data *dn, enum extent_type type)
 {
+	struct extent_info ei;
+
+	if (!__may_extent_tree(dn->inode, type))
+		return;
+
+	ei.fofs = f2fs_start_bidx_of_node(ofs_of_node(dn->node_page), dn->inode) +
+								dn->ofs_in_node;
+	ei.len = 1;
+
+	if (type == EX_READ) {
+		if (dn->data_blkaddr == NEW_ADDR)
+			ei.blk = NULL_ADDR;
+		else
+			ei.blk = dn->data_blkaddr;
+	}
+	__update_extent_tree_range(dn->inode, &ei, type);
+}
+
+static unsigned int __shrink_extent_tree(struct f2fs_sb_info *sbi, int nr_shrink,
+					enum extent_type type)
+{
+	struct extent_tree_info *eti = &sbi->extent_tree[type];
 	struct extent_tree *et, *next;
 	struct extent_node *en;
 	unsigned int node_cnt = 0, tree_cnt = 0;
 	int remained;
 
-	if (!test_opt(sbi, READ_EXTENT_CACHE))
+	if (!atomic_read(&eti->total_zombie_tree))
-		return 0;
-
-	if (!atomic_read(&sbi->total_zombie_tree))
 		goto free_node;
 
-	if (!mutex_trylock(&sbi->extent_tree_lock))
+	if (!mutex_trylock(&eti->extent_tree_lock))
 		goto out;
 
 	/* 1. remove unreferenced extent tree */
-	list_for_each_entry_safe(et, next, &sbi->zombie_list, list) {
+	list_for_each_entry_safe(et, next, &eti->zombie_list, list) {
 		if (atomic_read(&et->node_cnt)) {
 			write_lock(&et->lock);
 			node_cnt += __free_extent_tree(sbi, et);
@@ -787,61 +851,100 @@ unsigned int f2fs_shrink_extent_tree(struct f2fs_sb_info *sbi, int nr_shrink)
 		}
 		f2fs_bug_on(sbi, atomic_read(&et->node_cnt));
 		list_del_init(&et->list);
-		radix_tree_delete(&sbi->extent_tree_root, et->ino);
+		radix_tree_delete(&eti->extent_tree_root, et->ino);
 		kmem_cache_free(extent_tree_slab, et);
-		atomic_dec(&sbi->total_ext_tree);
+		atomic_dec(&eti->total_ext_tree);
-		atomic_dec(&sbi->total_zombie_tree);
+		atomic_dec(&eti->total_zombie_tree);
 		tree_cnt++;
 
 		if (node_cnt + tree_cnt >= nr_shrink)
 			goto unlock_out;
 		cond_resched();
 	}
-	mutex_unlock(&sbi->extent_tree_lock);
+	mutex_unlock(&eti->extent_tree_lock);
 
 free_node:
 	/* 2. remove LRU extent entries */
-	if (!mutex_trylock(&sbi->extent_tree_lock))
+	if (!mutex_trylock(&eti->extent_tree_lock))
 		goto out;
 
 	remained = nr_shrink - (node_cnt + tree_cnt);
 
-	spin_lock(&sbi->extent_lock);
+	spin_lock(&eti->extent_lock);
 	for (; remained > 0; remained--) {
-		if (list_empty(&sbi->extent_list))
+		if (list_empty(&eti->extent_list))
 			break;
-		en = list_first_entry(&sbi->extent_list,
+		en = list_first_entry(&eti->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);
+			list_move_tail(&en->list, &eti->extent_list);
 			continue;
 		}
 
 		list_del_init(&en->list);
-		spin_unlock(&sbi->extent_lock);
+		spin_unlock(&eti->extent_lock);
 
 		__detach_extent_node(sbi, et, en);
 
 		write_unlock(&et->lock);
 		node_cnt++;
-		spin_lock(&sbi->extent_lock);
+		spin_lock(&eti->extent_lock);
 	}
-	spin_unlock(&sbi->extent_lock);
+	spin_unlock(&eti->extent_lock);
 
 unlock_out:
-	mutex_unlock(&sbi->extent_tree_lock);
+	mutex_unlock(&eti->extent_tree_lock);
 out:
-	trace_f2fs_shrink_extent_tree(sbi, node_cnt, tree_cnt);
+	trace_f2fs_shrink_extent_tree(sbi, node_cnt, tree_cnt, type);
 
 	return node_cnt + tree_cnt;
 }
 
-unsigned int f2fs_destroy_extent_node(struct inode *inode)
+/* read extent cache operations */
+bool f2fs_lookup_read_extent_cache(struct inode *inode, pgoff_t pgofs,
+				struct extent_info *ei)
+{
+	if (!__may_extent_tree(inode, EX_READ))
+		return false;
+
+	return __lookup_extent_tree(inode, pgofs, ei, EX_READ);
+}
+
+void f2fs_update_read_extent_cache(struct dnode_of_data *dn)
+{
+	return __update_extent_cache(dn, EX_READ);
+}
+
+void f2fs_update_read_extent_cache_range(struct dnode_of_data *dn,
+				pgoff_t fofs, block_t blkaddr, unsigned int len)
+{
+	struct extent_info ei = {
+		.fofs = fofs,
+		.len = len,
+		.blk = blkaddr,
+	};
+
+	if (!__may_extent_tree(dn->inode, EX_READ))
+		return;
+
+	__update_extent_tree_range(dn->inode, &ei, EX_READ);
+}
+
+unsigned int f2fs_shrink_read_extent_tree(struct f2fs_sb_info *sbi, int nr_shrink)
+{
+	if (!test_opt(sbi, READ_EXTENT_CACHE))
+		return 0;
+
+	return __shrink_extent_tree(sbi, nr_shrink, EX_READ);
+}
+
+static unsigned int __destroy_extent_node(struct inode *inode,
+					enum extent_type type)
 {
 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
-	struct extent_tree *et = F2FS_I(inode)->extent_tree;
+	struct extent_tree *et = F2FS_I(inode)->extent_tree[type];
 	unsigned int node_cnt = 0;
 
 	if (!et || !atomic_read(&et->node_cnt))
@@ -854,31 +957,44 @@ unsigned int f2fs_destroy_extent_node(struct inode *inode)
 	return node_cnt;
 }
 
-void f2fs_drop_extent_tree(struct inode *inode)
+void f2fs_destroy_extent_node(struct inode *inode)
+{
+	__destroy_extent_node(inode, EX_READ);
+}
+
+static void __drop_extent_tree(struct inode *inode, enum extent_type type)
 {
 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
-	struct extent_tree *et = F2FS_I(inode)->extent_tree;
+	struct extent_tree *et = F2FS_I(inode)->extent_tree[type];
 	bool updated = false;
 
-	if (!f2fs_may_extent_tree(inode))
+	if (!__may_extent_tree(inode, type))
 		return;
 
 	write_lock(&et->lock);
-	set_inode_flag(inode, FI_NO_EXTENT);
 	__free_extent_tree(sbi, et);
-	if (et->largest.len) {
+	if (type == EX_READ) {
-		et->largest.len = 0;
+		set_inode_flag(inode, FI_NO_EXTENT);
-		updated = true;
+		if (et->largest.len) {
+			et->largest.len = 0;
+			updated = true;
+		}
 	}
 	write_unlock(&et->lock);
 	if (updated)
 		f2fs_mark_inode_dirty_sync(inode, true);
 }
 
-void f2fs_destroy_extent_tree(struct inode *inode)
+void f2fs_drop_extent_tree(struct inode *inode)
+{
+	__drop_extent_tree(inode, EX_READ);
+}
+
+static void __destroy_extent_tree(struct inode *inode, enum extent_type type)
 {
 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
-	struct extent_tree *et = F2FS_I(inode)->extent_tree;
+	struct extent_tree_info *eti = &sbi->extent_tree[type];
+	struct extent_tree *et = F2FS_I(inode)->extent_tree[type];
 	unsigned int node_cnt = 0;
 
 	if (!et)
@@ -886,76 +1002,49 @@ void f2fs_destroy_extent_tree(struct inode *inode)
 
 	if (inode->i_nlink && !is_bad_inode(inode) &&
 					atomic_read(&et->node_cnt)) {
-		mutex_lock(&sbi->extent_tree_lock);
+		mutex_lock(&eti->extent_tree_lock);
-		list_add_tail(&et->list, &sbi->zombie_list);
+		list_add_tail(&et->list, &eti->zombie_list);
-		atomic_inc(&sbi->total_zombie_tree);
+		atomic_inc(&eti->total_zombie_tree);
-		mutex_unlock(&sbi->extent_tree_lock);
+		mutex_unlock(&eti->extent_tree_lock);
 		return;
 	}
 
 	/* free all extent info belong to this extent tree */
-	node_cnt = f2fs_destroy_extent_node(inode);
+	node_cnt = __destroy_extent_node(inode, type);
 
 	/* delete extent tree entry in radix tree */
-	mutex_lock(&sbi->extent_tree_lock);
+	mutex_lock(&eti->extent_tree_lock);
 	f2fs_bug_on(sbi, atomic_read(&et->node_cnt));
-	radix_tree_delete(&sbi->extent_tree_root, inode->i_ino);
+	radix_tree_delete(&eti->extent_tree_root, inode->i_ino);
 	kmem_cache_free(extent_tree_slab, et);
-	atomic_dec(&sbi->total_ext_tree);
+	atomic_dec(&eti->total_ext_tree);
-	mutex_unlock(&sbi->extent_tree_lock);
+	mutex_unlock(&eti->extent_tree_lock);
 
-	F2FS_I(inode)->extent_tree = NULL;
+	F2FS_I(inode)->extent_tree[type] = NULL;
 
-	trace_f2fs_destroy_extent_tree(inode, node_cnt);
+	trace_f2fs_destroy_extent_tree(inode, node_cnt, type);
 }
 
-bool f2fs_lookup_extent_cache(struct inode *inode, pgoff_t pgofs,
+void f2fs_destroy_extent_tree(struct inode *inode)
-					struct extent_info *ei)
 {
-	if (!f2fs_may_extent_tree(inode))
+	__destroy_extent_tree(inode, EX_READ);
-		return false;
-
-	return f2fs_lookup_extent_tree(inode, pgofs, ei);
 }
 
-void f2fs_update_extent_cache(struct dnode_of_data *dn)
+static void __init_extent_tree_info(struct extent_tree_info *eti)
 {
-	pgoff_t fofs;
+	INIT_RADIX_TREE(&eti->extent_tree_root, GFP_NOIO);
-	block_t blkaddr;
+	mutex_init(&eti->extent_tree_lock);
-
+	INIT_LIST_HEAD(&eti->extent_list);
-	if (!f2fs_may_extent_tree(dn->inode))
+	spin_lock_init(&eti->extent_lock);
-		return;
+	atomic_set(&eti->total_ext_tree, 0);
-
+	INIT_LIST_HEAD(&eti->zombie_list);
-	if (dn->data_blkaddr == NEW_ADDR)
+	atomic_set(&eti->total_zombie_tree, 0);
-		blkaddr = NULL_ADDR;
+	atomic_set(&eti->total_ext_node, 0);
-	else
-		blkaddr = dn->data_blkaddr;
-
-	fofs = f2fs_start_bidx_of_node(ofs_of_node(dn->node_page), dn->inode) +
-								dn->ofs_in_node;
-	f2fs_update_extent_tree_range(dn->inode, fofs, blkaddr, 1);
-}
-
-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;
-
-	f2fs_update_extent_tree_range(dn->inode, fofs, blkaddr, len);
 }
 
 void f2fs_init_extent_cache_info(struct f2fs_sb_info *sbi)
 {
-	INIT_RADIX_TREE(&sbi->extent_tree_root, GFP_NOIO);
+	__init_extent_tree_info(&sbi->extent_tree[EX_READ]);
-	mutex_init(&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 f2fs_create_extent_cache(void)

fs/f2fs/f2fs.h

@@ -596,16 +596,22 @@ enum {
 /* dirty segments threshold for triggering CP */
 #define DEFAULT_DIRTY_THRESHOLD		4
 
+#define RECOVERY_MAX_RA_BLOCKS		BIO_MAX_VECS
+#define RECOVERY_MIN_RA_BLOCKS		1
+
+#define F2FS_ONSTACK_PAGES	16	/* nr of onstack pages */
+
 /* for in-memory extent cache entry */
 #define F2FS_MIN_EXTENT_LEN	64	/* minimum extent length */
 
 /* number of extent info in extent cache we try to shrink */
 #define READ_EXTENT_CACHE_SHRINK_NUMBER	128
 
-#define RECOVERY_MAX_RA_BLOCKS		BIO_MAX_VECS
+/* extent cache type */
-#define RECOVERY_MIN_RA_BLOCKS		1
+enum extent_type {
-
+	EX_READ,
-#define F2FS_ONSTACK_PAGES	16	/* nr of onstack pages */
+	NR_EXTENT_CACHES,
+};
 
 struct rb_entry {
 	struct rb_node rb_node;		/* rb node located in rb-tree */
@@ -621,10 +627,17 @@ struct rb_entry {
 struct extent_info {
 	unsigned int fofs;		/* start offset in a file */
 	unsigned int len;		/* length of the extent */
-	block_t blk;			/* start block address of the extent */
+	union {
+		/* read extent_cache */
+		struct {
+			/* start block address of the extent */
+			block_t blk;
 #ifdef CONFIG_F2FS_FS_COMPRESSION
-	unsigned int c_len;		/* physical extent length of compressed blocks */
+			/* physical extent length of compressed blocks */
+			unsigned int c_len;
 #endif
+		};
+	};
 };
 
 struct extent_node {
@@ -636,13 +649,25 @@ struct extent_node {
 
 struct extent_tree {
 	nid_t ino;			/* inode number */
+	enum extent_type type;		/* keep the extent tree type */
 	struct rb_root_cached root;	/* root of extent info rb-tree */
 	struct extent_node *cached_en;	/* recently accessed extent node */
-	struct extent_info largest;	/* largested extent info */
 	struct list_head list;		/* to be used by sbi->zombie_list */
 	rwlock_t lock;			/* protect extent info rb-tree */
 	atomic_t node_cnt;		/* # of extent node in rb-tree*/
 	bool largest_updated;		/* largest extent updated */
+	struct extent_info largest;	/* largest cached extent for EX_READ */
+};
+
+struct extent_tree_info {
+	struct radix_tree_root extent_tree_root;/* cache extent cache entries */
+	struct mutex extent_tree_lock;	/* locking extent radix tree */
+	struct list_head extent_list;		/* lru list for shrinker */
+	spinlock_t extent_lock;			/* locking extent lru list */
+	atomic_t total_ext_tree;		/* extent tree count */
+	struct list_head zombie_list;		/* extent zombie tree list */
+	atomic_t total_zombie_tree;		/* extent zombie tree count */
+	atomic_t total_ext_node;		/* extent info count */
 };
 
 /*
@@ -805,7 +830,8 @@ struct f2fs_inode_info {
 	struct list_head dirty_list;	/* dirty list for dirs and files */
 	struct list_head gdirty_list;	/* linked in global dirty list */
 	struct task_struct *atomic_write_task;	/* store atomic write task */
-	struct extent_tree *extent_tree;	/* cached extent_tree entry */
+	struct extent_tree *extent_tree[NR_EXTENT_CACHES];
+					/* cached extent_tree entry */
 	struct inode *cow_inode;	/* copy-on-write inode for atomic write */
 
 	/* avoid racing between foreground op and gc */
@@ -1626,14 +1652,7 @@ struct f2fs_sb_info {
 	struct mutex flush_lock;		/* for flush exclusion */
 
 	/* for extent tree cache */
-	struct radix_tree_root extent_tree_root;/* cache extent cache entries */
+	struct extent_tree_info extent_tree[NR_EXTENT_CACHES];
-	struct mutex extent_tree_lock;	/* locking extent radix tree */
-	struct list_head extent_list;		/* lru list for shrinker */
-	spinlock_t extent_lock;			/* locking extent lru list */
-	atomic_t total_ext_tree;		/* extent tree count */
-	struct list_head zombie_list;		/* extent zombie tree list */
-	atomic_t total_zombie_tree;		/* extent zombie tree count */
-	atomic_t total_ext_node;		/* extent info count */
 
 	/* basic filesystem units */
 	unsigned int log_sectors_per_block;	/* log2 sectors per block */
@@ -1718,10 +1737,14 @@ struct f2fs_sb_info {
 	unsigned int segment_count[2];		/* # of allocated segments */
 	unsigned int block_count[2];		/* # of allocated blocks */
 	atomic_t inplace_count;		/* # of inplace update */
-	atomic64_t total_hit_ext;		/* # of lookup extent cache */
+	/* # of lookup extent cache */
-	atomic64_t read_hit_rbtree;		/* # of hit rbtree extent node */
+	atomic64_t total_hit_ext[NR_EXTENT_CACHES];
-	atomic64_t read_hit_largest;		/* # of hit largest extent node */
+	/* # of hit rbtree extent node */
-	atomic64_t read_hit_cached;		/* # of hit cached extent node */
+	atomic64_t read_hit_rbtree[NR_EXTENT_CACHES];
+	/* # of hit cached extent node */
+	atomic64_t read_hit_cached[NR_EXTENT_CACHES];
+	/* # of hit largest extent node in read extent cache */
+	atomic64_t read_hit_largest;
 	atomic_t inline_xattr;			/* # of inline_xattr inodes */
 	atomic_t inline_inode;			/* # of inline_data inodes */
 	atomic_t inline_dir;			/* # of inline_dentry inodes */
@@ -3823,9 +3846,17 @@ struct f2fs_stat_info {
 	struct f2fs_sb_info *sbi;
 	int all_area_segs, sit_area_segs, nat_area_segs, ssa_area_segs;
 	int main_area_segs, main_area_sections, main_area_zones;
-	unsigned long long hit_largest, hit_cached, hit_rbtree;
+	unsigned long long hit_cached[NR_EXTENT_CACHES];
-	unsigned long long hit_total, total_ext;
+	unsigned long long hit_rbtree[NR_EXTENT_CACHES];
-	int ext_tree, zombie_tree, ext_node;
+	unsigned long long total_ext[NR_EXTENT_CACHES];
+	unsigned long long hit_total[NR_EXTENT_CACHES];
+	int ext_tree[NR_EXTENT_CACHES];
+	int zombie_tree[NR_EXTENT_CACHES];
+	int ext_node[NR_EXTENT_CACHES];
+	/* to count memory footprint */
+	unsigned long long ext_mem[NR_EXTENT_CACHES];
+	/* for read extent cache */
+	unsigned long long hit_largest;
 	int ndirty_node, ndirty_dent, ndirty_meta, ndirty_imeta;
 	int ndirty_data, ndirty_qdata;
 	unsigned int ndirty_dirs, ndirty_files, nquota_files, ndirty_all;
@@ -3884,10 +3915,10 @@ static inline struct f2fs_stat_info *F2FS_STAT(struct f2fs_sb_info *sbi)
 #define stat_other_skip_bggc_count(sbi)	((sbi)->other_skip_bggc++)
 #define stat_inc_dirty_inode(sbi, type)	((sbi)->ndirty_inode[type]++)
 #define stat_dec_dirty_inode(sbi, type)	((sbi)->ndirty_inode[type]--)
-#define stat_inc_total_hit(sbi)		(atomic64_inc(&(sbi)->total_hit_ext))
+#define stat_inc_total_hit(sbi, type)		(atomic64_inc(&(sbi)->total_hit_ext[type]))
-#define stat_inc_rbtree_node_hit(sbi)	(atomic64_inc(&(sbi)->read_hit_rbtree))
+#define stat_inc_rbtree_node_hit(sbi, type)	(atomic64_inc(&(sbi)->read_hit_rbtree[type]))
 #define stat_inc_largest_node_hit(sbi)	(atomic64_inc(&(sbi)->read_hit_largest))
-#define stat_inc_cached_node_hit(sbi)	(atomic64_inc(&(sbi)->read_hit_cached))
+#define stat_inc_cached_node_hit(sbi, type)	(atomic64_inc(&(sbi)->read_hit_cached[type]))
 #define stat_inc_inline_xattr(inode)					\
 	do {								\
 		if (f2fs_has_inline_xattr(inode))			\
@@ -4010,10 +4041,10 @@ void f2fs_update_sit_info(struct f2fs_sb_info *sbi);
 #define stat_other_skip_bggc_count(sbi)			do { } while (0)
 #define stat_inc_dirty_inode(sbi, type)			do { } while (0)
 #define stat_dec_dirty_inode(sbi, type)			do { } while (0)
-#define stat_inc_total_hit(sbi)				do { } while (0)
+#define stat_inc_total_hit(sbi, type)			do { } while (0)
-#define stat_inc_rbtree_node_hit(sbi)			do { } while (0)
+#define stat_inc_rbtree_node_hit(sbi, type)		do { } while (0)
 #define stat_inc_largest_node_hit(sbi)			do { } while (0)
-#define stat_inc_cached_node_hit(sbi)			do { } while (0)
+#define stat_inc_cached_node_hit(sbi, type)		do { } while (0)
 #define stat_inc_inline_xattr(inode)			do { } while (0)
 #define stat_dec_inline_xattr(inode)			do { } while (0)
 #define stat_inc_inline_inode(inode)			do { } while (0)
@@ -4119,20 +4150,23 @@ struct rb_entry *f2fs_lookup_rb_tree_ret(struct rb_root_cached *root,
 		bool force, bool *leftmost);
 bool f2fs_check_rb_tree_consistence(struct f2fs_sb_info *sbi,
 				struct rb_root_cached *root, bool check_key);
-unsigned int f2fs_shrink_extent_tree(struct f2fs_sb_info *sbi, int nr_shrink);
 void f2fs_init_extent_tree(struct inode *inode, struct page *ipage);
 void f2fs_drop_extent_tree(struct inode *inode);
-unsigned int f2fs_destroy_extent_node(struct inode *inode);
+void f2fs_destroy_extent_node(struct inode *inode);
 void f2fs_destroy_extent_tree(struct inode *inode);
-bool f2fs_lookup_extent_cache(struct inode *inode, pgoff_t pgofs,
-			struct extent_info *ei);
-void f2fs_update_extent_cache(struct dnode_of_data *dn);
-void f2fs_update_extent_cache_range(struct dnode_of_data *dn,
-			pgoff_t fofs, block_t blkaddr, unsigned int len);
 void f2fs_init_extent_cache_info(struct f2fs_sb_info *sbi);
 int __init f2fs_create_extent_cache(void);
 void f2fs_destroy_extent_cache(void);
 
+/* read extent cache ops */
+bool f2fs_lookup_read_extent_cache(struct inode *inode, pgoff_t pgofs,
+			struct extent_info *ei);
+void f2fs_update_read_extent_cache(struct dnode_of_data *dn);
+void f2fs_update_read_extent_cache_range(struct dnode_of_data *dn,
+			pgoff_t fofs, block_t blkaddr, unsigned int len);
+unsigned int f2fs_shrink_read_extent_tree(struct f2fs_sb_info *sbi,
+			int nr_shrink);
+
 /*
  * sysfs.c
  */
@@ -4202,9 +4236,9 @@ int f2fs_write_multi_pages(struct compress_ctx *cc,
 						struct writeback_control *wbc,
 						enum iostat_type io_type);
 int f2fs_is_compressed_cluster(struct inode *inode, pgoff_t index);
-void f2fs_update_extent_tree_range_compressed(struct inode *inode,
+void f2fs_update_read_extent_tree_range_compressed(struct inode *inode,
-				pgoff_t fofs, block_t blkaddr, unsigned int llen,
+				pgoff_t fofs, block_t blkaddr,
-				unsigned int c_len);
+				unsigned int llen, unsigned int c_len);
 int f2fs_read_multi_pages(struct compress_ctx *cc, struct bio **bio_ret,
 				unsigned nr_pages, sector_t *last_block_in_bio,
 				bool is_readahead, bool for_write);
@@ -4285,9 +4319,10 @@ static inline bool f2fs_load_compressed_page(struct f2fs_sb_info *sbi,
 static inline void f2fs_invalidate_compress_pages(struct f2fs_sb_info *sbi,
 							nid_t ino) { }
 #define inc_compr_inode_stat(inode)		do { } while (0)
-static inline void f2fs_update_extent_tree_range_compressed(struct inode *inode,
+static inline void f2fs_update_read_extent_tree_range_compressed(
-				pgoff_t fofs, block_t blkaddr, unsigned int llen,
+				struct inode *inode,
-				unsigned int c_len) { }
+				pgoff_t fofs, block_t blkaddr,
+				unsigned int llen, unsigned int c_len) { }
 #endif
 
 static inline int set_compress_context(struct inode *inode)

fs/f2fs/file.c

@@ -618,7 +618,7 @@ void f2fs_truncate_data_blocks_range(struct dnode_of_data *dn, int count)
 		 */
 		fofs = f2fs_start_bidx_of_node(ofs_of_node(dn->node_page),
 							dn->inode) + ofs;
-		f2fs_update_extent_cache_range(dn, fofs, 0, len);
+		f2fs_update_read_extent_cache_range(dn, fofs, 0, len);
 		dec_valid_block_count(sbi, dn->inode, nr_free);
 	}
 	dn->ofs_in_node = ofs;
@@ -1496,7 +1496,7 @@ static int f2fs_do_zero_range(struct dnode_of_data *dn, pgoff_t start,
 		f2fs_set_data_blkaddr(dn);
 	}
 
-	f2fs_update_extent_cache_range(dn, start, 0, index - start);
+	f2fs_update_read_extent_cache_range(dn, start, 0, index - start);
 
 	return ret;
 }
@@ -2558,7 +2558,7 @@ static int f2fs_defragment_range(struct f2fs_sb_info *sbi,
 	struct f2fs_map_blocks map = { .m_next_extent = NULL,
 					.m_seg_type = NO_CHECK_TYPE,
 					.m_may_create = false };
-	struct extent_info ei = {0, 0, 0};
+	struct extent_info ei = {0, };
 	pgoff_t pg_start, pg_end, next_pgofs;
 	unsigned int blk_per_seg = sbi->blocks_per_seg;
 	unsigned int total = 0, sec_num;
@@ -2590,7 +2590,7 @@ static int f2fs_defragment_range(struct f2fs_sb_info *sbi,
 	 * lookup mapping info in extent cache, skip defragmenting if physical
 	 * block addresses are continuous.
 	 */
-	if (f2fs_lookup_extent_cache(inode, pg_start, &ei)) {
+	if (f2fs_lookup_read_extent_cache(inode, pg_start, &ei)) {
 		if (ei.fofs + ei.len >= pg_end)
 			goto out;
 	}

fs/f2fs/gc.c

@@ -1146,7 +1146,7 @@ static int ra_data_block(struct inode *inode, pgoff_t index)
 	struct address_space *mapping = inode->i_mapping;
 	struct dnode_of_data dn;
 	struct page *page;
-	struct extent_info ei = {0, 0, 0};
+	struct extent_info ei = {0, };
 	struct f2fs_io_info fio = {
 		.sbi = sbi,
 		.ino = inode->i_ino,
@@ -1164,7 +1164,7 @@ static int ra_data_block(struct inode *inode, pgoff_t index)
 	if (!page)
 		return -ENOMEM;
 
-	if (f2fs_lookup_extent_cache(inode, index, &ei)) {
+	if (f2fs_lookup_read_extent_cache(inode, index, &ei)) {
 		dn.data_blkaddr = ei.blk + index - ei.fofs;
 		if (unlikely(!f2fs_is_valid_blkaddr(sbi, dn.data_blkaddr,
 						DATA_GENERIC_ENHANCE_READ))) {

fs/f2fs/inode.c

@@ -262,8 +262,8 @@ static bool sanity_check_inode(struct inode *inode, struct page *node_page)
 		return false;
 	}
 
-	if (fi->extent_tree) {
+	if (fi->extent_tree[EX_READ]) {
-		struct extent_info *ei = &fi->extent_tree->largest;
+		struct extent_info *ei = &fi->extent_tree[EX_READ]->largest;
 
 		if (ei->len &&
 			(!f2fs_is_valid_blkaddr(sbi, ei->blk,
@@ -607,7 +607,7 @@ retry:
 void f2fs_update_inode(struct inode *inode, struct page *node_page)
 {
 	struct f2fs_inode *ri;
-	struct extent_tree *et = F2FS_I(inode)->extent_tree;
+	struct extent_tree *et = F2FS_I(inode)->extent_tree[EX_READ];
 
 	f2fs_wait_on_page_writeback(node_page, NODE, true, true);
 	set_page_dirty(node_page);

fs/f2fs/node.c

@@ -86,9 +86,11 @@ bool f2fs_available_free_memory(struct f2fs_sb_info *sbi, int type)
 		mem_size >>= PAGE_SHIFT;
 		res = mem_size < ((avail_ram * nm_i->ram_thresh / 100) >> 1);
 	} else if (type == READ_EXTENT_CACHE) {
-		mem_size = (atomic_read(&sbi->total_ext_tree) *
+		struct extent_tree_info *eti = &sbi->extent_tree[EX_READ];
+
+		mem_size = (atomic_read(&eti->total_ext_tree) *
 				sizeof(struct extent_tree) +
-				atomic_read(&sbi->total_ext_node) *
+				atomic_read(&eti->total_ext_node) *
 				sizeof(struct extent_node)) >> PAGE_SHIFT;
 		res = mem_size < ((avail_ram * nm_i->ram_thresh / 100) >> 1);
 	} else if (type == DISCARD_CACHE) {
@@ -859,7 +861,7 @@ int f2fs_get_dnode_of_data(struct dnode_of_data *dn, pgoff_t index, int mode)
 			blkaddr = data_blkaddr(dn->inode, dn->node_page,
 						dn->ofs_in_node + 1);
 
-		f2fs_update_extent_tree_range_compressed(dn->inode,
+		f2fs_update_read_extent_tree_range_compressed(dn->inode,
 					index, blkaddr,
 					F2FS_I(dn->inode)->i_cluster_size,
 					c_len);

fs/f2fs/segment.c

@@ -450,7 +450,8 @@ void f2fs_balance_fs_bg(struct f2fs_sb_info *sbi, bool from_bg)
 
 	/* try to shrink extent cache when there is no enough memory */
 	if (!f2fs_available_free_memory(sbi, READ_EXTENT_CACHE))
-		f2fs_shrink_extent_tree(sbi, READ_EXTENT_CACHE_SHRINK_NUMBER);
+		f2fs_shrink_read_extent_tree(sbi,
+				READ_EXTENT_CACHE_SHRINK_NUMBER);
 
 	/* check the # of cached NAT entries */
 	if (!f2fs_available_free_memory(sbi, NAT_ENTRIES))

fs/f2fs/shrinker.c

@@ -28,10 +28,13 @@ static unsigned long __count_free_nids(struct f2fs_sb_info *sbi)
 	return count > 0 ? count : 0;
 }
 
-static unsigned long __count_extent_cache(struct f2fs_sb_info *sbi)
+static unsigned long __count_extent_cache(struct f2fs_sb_info *sbi,
+					enum extent_type type)
 {
-	return atomic_read(&sbi->total_zombie_tree) +
+	struct extent_tree_info *eti = &sbi->extent_tree[type];
-				atomic_read(&sbi->total_ext_node);
+
+	return atomic_read(&eti->total_zombie_tree) +
+				atomic_read(&eti->total_ext_node);
 }
 
 unsigned long f2fs_shrink_count(struct shrinker *shrink,
@@ -53,8 +56,8 @@ unsigned long f2fs_shrink_count(struct shrinker *shrink,
 		}
 		spin_unlock(&f2fs_list_lock);
 
-		/* count extent cache entries */
+		/* count read extent cache entries */
-		count += __count_extent_cache(sbi);
+		count += __count_extent_cache(sbi, EX_READ);
 
 		/* count clean nat cache entries */
 		count += __count_nat_entries(sbi);
@@ -99,8 +102,8 @@ unsigned long f2fs_shrink_scan(struct shrinker *shrink,
 
 		sbi->shrinker_run_no = run_no;
 
-		/* shrink extent cache entries */
+		/* shrink read extent cache entries */
-		freed += f2fs_shrink_extent_tree(sbi, nr >> 1);
+		freed += f2fs_shrink_read_extent_tree(sbi, nr >> 1);
 
 		/* shrink clean nat cache entries */
 		if (freed < nr)
@@ -130,7 +133,7 @@ void f2fs_join_shrinker(struct f2fs_sb_info *sbi)
 
 void f2fs_leave_shrinker(struct f2fs_sb_info *sbi)
 {
-	f2fs_shrink_extent_tree(sbi, __count_extent_cache(sbi));
+	f2fs_shrink_read_extent_tree(sbi, __count_extent_cache(sbi, EX_READ));
 
 	spin_lock(&f2fs_list_lock);
 	list_del_init(&sbi->s_list);

include/trace/events/f2fs.h

@@ -48,6 +48,7 @@ TRACE_DEFINE_ENUM(CP_DISCARD);
 TRACE_DEFINE_ENUM(CP_TRIMMED);
 TRACE_DEFINE_ENUM(CP_PAUSE);
 TRACE_DEFINE_ENUM(CP_RESIZE);
+TRACE_DEFINE_ENUM(EX_READ);
 
 #define show_block_type(type)						\
 	__print_symbolic(type,						\
@@ -1522,28 +1523,31 @@ TRACE_EVENT(f2fs_issue_flush,
 
 TRACE_EVENT(f2fs_lookup_extent_tree_start,
 
-	TP_PROTO(struct inode *inode, unsigned int pgofs),
+	TP_PROTO(struct inode *inode, unsigned int pgofs, enum extent_type type),
 
-	TP_ARGS(inode, pgofs),
+	TP_ARGS(inode, pgofs, type),
 
 	TP_STRUCT__entry(
 		__field(dev_t,	dev)
 		__field(ino_t,	ino)
 		__field(unsigned int, pgofs)
+		__field(enum extent_type, type)
 	),
 
 	TP_fast_assign(
 		__entry->dev = inode->i_sb->s_dev;
 		__entry->ino = inode->i_ino;
 		__entry->pgofs = pgofs;
+		__entry->type = type;
 	),
 
-	TP_printk("dev = (%d,%d), ino = %lu, pgofs = %u",
+	TP_printk("dev = (%d,%d), ino = %lu, pgofs = %u, type = %s",
 		show_dev_ino(__entry),
-		__entry->pgofs)
+		__entry->pgofs,
+		__entry->type == EX_READ ? "Read" : "N/A")
 );
 
-TRACE_EVENT_CONDITION(f2fs_lookup_extent_tree_end,
+TRACE_EVENT_CONDITION(f2fs_lookup_read_extent_tree_end,
 
 	TP_PROTO(struct inode *inode, unsigned int pgofs,
 						struct extent_info *ei),
@@ -1557,8 +1561,8 @@ TRACE_EVENT_CONDITION(f2fs_lookup_extent_tree_end,
 		__field(ino_t,	ino)
 		__field(unsigned int, pgofs)
 		__field(unsigned int, fofs)
-		__field(u32, blk)
 		__field(unsigned int, len)
+		__field(u32, blk)
 	),
 
 	TP_fast_assign(
@@ -1566,26 +1570,26 @@ TRACE_EVENT_CONDITION(f2fs_lookup_extent_tree_end,
 		__entry->ino = inode->i_ino;
 		__entry->pgofs = pgofs;
 		__entry->fofs = ei->fofs;
-		__entry->blk = ei->blk;
 		__entry->len = ei->len;
+		__entry->blk = ei->blk;
 	),
 
 	TP_printk("dev = (%d,%d), ino = %lu, pgofs = %u, "
-		"ext_info(fofs: %u, blk: %u, len: %u)",
+		"read_ext_info(fofs: %u, len: %u, blk: %u)",
 		show_dev_ino(__entry),
 		__entry->pgofs,
 		__entry->fofs,
-		__entry->blk,
+		__entry->len,
-		__entry->len)
+		__entry->blk)
 );
 
-TRACE_EVENT(f2fs_update_extent_tree_range,
+TRACE_EVENT(f2fs_update_read_extent_tree_range,
 
-	TP_PROTO(struct inode *inode, unsigned int pgofs, block_t blkaddr,
+	TP_PROTO(struct inode *inode, unsigned int pgofs, unsigned int len,
-						unsigned int len,
+						block_t blkaddr,
 						unsigned int c_len),
 
-	TP_ARGS(inode, pgofs, blkaddr, len, c_len),
+	TP_ARGS(inode, pgofs, len, blkaddr, c_len),
 
 	TP_STRUCT__entry(
 		__field(dev_t,	dev)
@@ -1600,67 +1604,73 @@ TRACE_EVENT(f2fs_update_extent_tree_range,
 		__entry->dev = inode->i_sb->s_dev;
 		__entry->ino = inode->i_ino;
 		__entry->pgofs = pgofs;
-		__entry->blk = blkaddr;
 		__entry->len = len;
+		__entry->blk = blkaddr;
 		__entry->c_len = c_len;
 	),
 
 	TP_printk("dev = (%d,%d), ino = %lu, pgofs = %u, "
-					"blkaddr = %u, len = %u, "
+				"len = %u, blkaddr = %u, c_len = %u",
-					"c_len = %u",
 		show_dev_ino(__entry),
 		__entry->pgofs,
-		__entry->blk,
 		__entry->len,
+		__entry->blk,
 		__entry->c_len)
 );
 
 TRACE_EVENT(f2fs_shrink_extent_tree,
 
 	TP_PROTO(struct f2fs_sb_info *sbi, unsigned int node_cnt,
-						unsigned int tree_cnt),
+			unsigned int tree_cnt, enum extent_type type),
 
-	TP_ARGS(sbi, node_cnt, tree_cnt),
+	TP_ARGS(sbi, node_cnt, tree_cnt, type),
 
 	TP_STRUCT__entry(
 		__field(dev_t,	dev)
 		__field(unsigned int, node_cnt)
 		__field(unsigned int, tree_cnt)
+		__field(enum extent_type, type)
 	),
 
 	TP_fast_assign(
 		__entry->dev = sbi->sb->s_dev;
 		__entry->node_cnt = node_cnt;
 		__entry->tree_cnt = tree_cnt;
+		__entry->type = type;
 	),
 
-	TP_printk("dev = (%d,%d), shrunk: node_cnt = %u, tree_cnt = %u",
+	TP_printk("dev = (%d,%d), shrunk: node_cnt = %u, tree_cnt = %u, type = %s",
 		show_dev(__entry->dev),
 		__entry->node_cnt,
-		__entry->tree_cnt)
+		__entry->tree_cnt,
+		__entry->type == EX_READ ? "Read" : "N/A")
 );
 
 TRACE_EVENT(f2fs_destroy_extent_tree,
 
-	TP_PROTO(struct inode *inode, unsigned int node_cnt),
+	TP_PROTO(struct inode *inode, unsigned int node_cnt,
+				enum extent_type type),
 
-	TP_ARGS(inode, node_cnt),
+	TP_ARGS(inode, node_cnt, type),
 
 	TP_STRUCT__entry(
 		__field(dev_t,	dev)
 		__field(ino_t,	ino)
 		__field(unsigned int, node_cnt)
+		__field(enum extent_type, type)
 	),
 
 	TP_fast_assign(
 		__entry->dev = inode->i_sb->s_dev;
 		__entry->ino = inode->i_ino;
 		__entry->node_cnt = node_cnt;
+		__entry->type = type;
 	),
 
-	TP_printk("dev = (%d,%d), ino = %lu, destroyed: node_cnt = %u",
+	TP_printk("dev = (%d,%d), ino = %lu, destroyed: node_cnt = %u, type = %s",
 		show_dev_ino(__entry),
-		__entry->node_cnt)
+		__entry->node_cnt,
+		__entry->type == EX_READ ? "Read" : "N/A")
 );
 
 DECLARE_EVENT_CLASS(f2fs_sync_dirty_inodes,