Re: [PATCH RESEND v2 1/5] f2fs: compress: add compress_inode to cache compressed blocks

[Chao Yu <yuchao0@huawei.com>]

Hi Daeho, Jaegeuk

I found one missing place in this patch which should adapt
"compress vs verity race bugfix"

Could you please check and apply below diff?

 From 61a9812944ac2f6f64fb458d5ef8b662c007bc50 Mon Sep 17 00:00:00 2001
From: Chao Yu <yuchao0@huawei.com>
Date: Thu, 10 Dec 2020 09:52:42 +0800
Subject: [PATCH] fix

Signed-off-by: Chao Yu <yuchao0@huawei.com>
---
  fs/f2fs/data.c | 7 ++-----
  1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 6787a7a03e86..894c5680db4a 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -2271,11 +2271,8 @@ int f2fs_read_multi_pages(struct compress_ctx *cc, struct bio **bio_ret,
  		f2fs_load_compressed_page(sbi, page, blkaddr);
  		if (PageUptodate(page)) {
  			if (!atomic_dec_return(&dic->pending_pages)) {
-				bool verity =
-					f2fs_need_verity(inode, start_idx);
-
-				f2fs_do_decompress_pages(dic, verity);
-				if (verity) {
+				f2fs_do_decompress_pages(dic, for_verity);
+				if (for_verity) {
  					f2fs_verify_pages(dic->rpages,
  							dic->cluster_size);
  					f2fs_free_dic(dic);
-- 
2.29.2

Thanks,

On 2020/12/9 16:43, Chao Yu wrote:
> Support to use address space of inner inode to cache compressed block,
> in order to improve cache hit ratio of random read.
> 
> Signed-off-by: Chao Yu <yuchao0@huawei.com>
> ---
>   Documentation/filesystems/f2fs.rst |   3 +
>   fs/f2fs/compress.c                 | 198 +++++++++++++++++++++++++++--
>   fs/f2fs/data.c                     |  29 ++++-
>   fs/f2fs/debug.c                    |  13 ++
>   fs/f2fs/f2fs.h                     |  34 ++++-
>   fs/f2fs/gc.c                       |   1 +
>   fs/f2fs/inode.c                    |  21 ++-
>   fs/f2fs/segment.c                  |   6 +-
>   fs/f2fs/super.c                    |  19 ++-
>   include/linux/f2fs_fs.h            |   1 +
>   10 files changed, 305 insertions(+), 20 deletions(-)
> 
> diff --git a/Documentation/filesystems/f2fs.rst b/Documentation/filesystems/f2fs.rst
> index dae15c96e659..5fa45fd8e4af 100644
> --- a/Documentation/filesystems/f2fs.rst
> +++ b/Documentation/filesystems/f2fs.rst
> @@ -268,6 +268,9 @@ compress_mode=%s	 Control file compression mode. This supports "fs" and "user"
>   			 choosing the target file and the timing. The user can do manual
>   			 compression/decompression on the compression enabled files using
>   			 ioctls.
> +compress_cache		 Support to use address space of a filesystem managed inode to
> +			 cache compressed block, in order to improve cache hit ratio of
> +			 random read.
>   inlinecrypt		 When possible, encrypt/decrypt the contents of encrypted
>   			 files using the blk-crypto framework rather than
>   			 filesystem-layer encryption. This allows the use of
> diff --git a/fs/f2fs/compress.c b/fs/f2fs/compress.c
> index 4bcbacfe3325..446dd41a7bad 100644
> --- a/fs/f2fs/compress.c
> +++ b/fs/f2fs/compress.c
> @@ -12,9 +12,11 @@
>   #include <linux/lzo.h>
>   #include <linux/lz4.h>
>   #include <linux/zstd.h>
> +#include <linux/pagevec.h>
>   
>   #include "f2fs.h"
>   #include "node.h"
> +#include "segment.h"
>   #include <trace/events/f2fs.h>
>   
>   static struct kmem_cache *cic_entry_slab;
> @@ -721,25 +723,14 @@ static int f2fs_compress_pages(struct compress_ctx *cc)
>   	return ret;
>   }
>   
> -void f2fs_decompress_pages(struct bio *bio, struct page *page, bool verity)
> +void f2fs_do_decompress_pages(struct decompress_io_ctx *dic, bool verity)
>   {
> -	struct decompress_io_ctx *dic =
> -			(struct decompress_io_ctx *)page_private(page);
> -	struct f2fs_sb_info *sbi = F2FS_I_SB(dic->inode);
>   	struct f2fs_inode_info *fi= F2FS_I(dic->inode);
>   	const struct f2fs_compress_ops *cops =
>   			f2fs_cops[fi->i_compress_algorithm];
>   	int ret;
>   	int i;
>   
> -	dec_page_count(sbi, F2FS_RD_DATA);
> -
> -	if (bio->bi_status || PageError(page))
> -		dic->failed = true;
> -
> -	if (atomic_dec_return(&dic->pending_pages))
> -		return;
> -
>   	trace_f2fs_decompress_pages_start(dic->inode, dic->cluster_idx,
>   				dic->cluster_size, fi->i_compress_algorithm);
>   
> @@ -797,6 +788,7 @@ void f2fs_decompress_pages(struct bio *bio, struct page *page, bool verity)
>   	ret = cops->decompress_pages(dic);
>   
>   	if (!ret && (fi->i_compress_flag & 1 << COMPRESS_CHKSUM)) {
> +		struct f2fs_sb_info *sbi = F2FS_I_SB(dic->inode);
>   		u32 provided = le32_to_cpu(dic->cbuf->chksum);
>   		u32 calculated = f2fs_crc32(sbi, dic->cbuf->cdata, dic->clen);
>   
> @@ -830,6 +822,30 @@ void f2fs_decompress_pages(struct bio *bio, struct page *page, bool verity)
>   		f2fs_free_dic(dic);
>   }
>   
> +void f2fs_cache_compressed_page(struct f2fs_sb_info *sbi, struct page *page,
> +						nid_t ino, block_t blkaddr);
> +void f2fs_decompress_pages(struct bio *bio, struct page *page,
> +						bool verity, unsigned int ofs)
> +{
> +	struct decompress_io_ctx *dic =
> +			(struct decompress_io_ctx *)page_private(page);
> +	struct f2fs_sb_info *sbi = F2FS_I_SB(dic->inode);
> +	block_t blkaddr;
> +
> +	dec_page_count(sbi, F2FS_RD_DATA);
> +
> +	if (bio->bi_status || PageError(page))
> +		dic->failed = true;
> +
> +	blkaddr = SECTOR_TO_BLOCK(bio->bi_iter.bi_sector) + ofs;
> +	f2fs_cache_compressed_page(sbi, page, dic->inode->i_ino, blkaddr);
> +
> +	if (atomic_dec_return(&dic->pending_pages))
> +		return;
> +
> +	f2fs_do_decompress_pages(dic, verity);
> +}
> +
>   static bool is_page_in_cluster(struct compress_ctx *cc, pgoff_t index)
>   {
>   	if (cc->cluster_idx == NULL_CLUSTER)
> @@ -1600,6 +1616,164 @@ void f2fs_decompress_end_io(struct page **rpages,
>   	}
>   }
>   
> +const struct address_space_operations f2fs_compress_aops = {
> +	.releasepage = f2fs_release_page,
> +	.invalidatepage = f2fs_invalidate_page,
> +};
> +
> +struct address_space *COMPRESS_MAPPING(struct f2fs_sb_info *sbi)
> +{
> +	return sbi->compress_inode->i_mapping;
> +}
> +
> +void f2fs_invalidate_compress_page(struct f2fs_sb_info *sbi, block_t blkaddr)
> +{
> +	if (!sbi->compress_inode)
> +		return;
> +	invalidate_mapping_pages(COMPRESS_MAPPING(sbi), blkaddr, blkaddr);
> +}
> +
> +void f2fs_cache_compressed_page(struct f2fs_sb_info *sbi, struct page *page,
> +						nid_t ino, block_t blkaddr)
> +{
> +	struct page *cpage;
> +	int ret;
> +	struct sysinfo si;
> +	unsigned long free_ram, avail_ram;
> +
> +	if (!test_opt(sbi, COMPRESS_CACHE))
> +		return;
> +
> +	si_meminfo(&si);
> +	free_ram = si.freeram;
> +	avail_ram = si.totalram - si.totalhigh;
> +
> +	/* free memory is lower than watermark, deny caching compress page */
> +	if (free_ram <= sbi->compress_watermark / 100 * avail_ram)
> +		return;
> +
> +	/* cached page count exceed threshold, deny caching compress page */
> +	if (COMPRESS_MAPPING(sbi)->nrpages >=
> +			free_ram / 100 * sbi->compress_percent)
> +		return;
> +
> +	cpage = find_get_page(COMPRESS_MAPPING(sbi), blkaddr);
> +	if (cpage) {
> +		f2fs_put_page(cpage, 0);
> +		return;
> +	}
> +
> +	cpage = alloc_page(__GFP_IO);
> +	if (!cpage)
> +		return;
> +
> +	ret = add_to_page_cache_lru(cpage, COMPRESS_MAPPING(sbi),
> +						blkaddr, GFP_NOFS);
> +	if (ret) {
> +		f2fs_put_page(cpage, 0);
> +		return;
> +	}
> +
> +	memcpy(page_address(cpage), page_address(page), PAGE_SIZE);
> +	SetPageUptodate(cpage);
> +
> +	f2fs_set_page_private(cpage, ino);
> +
> +	f2fs_put_page(cpage, 1);
> +}
> +
> +void f2fs_load_compressed_page(struct f2fs_sb_info *sbi, struct page *page,
> +								block_t blkaddr)
> +{
> +	struct page *cpage;
> +
> +	if (!test_opt(sbi, COMPRESS_CACHE))
> +		return;
> +
> +	cpage = f2fs_pagecache_get_page(COMPRESS_MAPPING(sbi),
> +				blkaddr, FGP_LOCK | FGP_NOWAIT, GFP_NOFS);
> +	if (cpage) {
> +		if (PageUptodate(cpage)) {
> +			atomic_inc(&sbi->compress_page_hit);
> +			memcpy(page_address(page),
> +				page_address(cpage), PAGE_SIZE);
> +			SetPageUptodate(page);
> +		}
> +		f2fs_put_page(cpage, 1);
> +	}
> +}
> +
> +void f2fs_invalidate_compress_pages(struct f2fs_sb_info *sbi, nid_t ino)
> +{
> +	struct address_space *mapping = sbi->compress_inode->i_mapping;
> +	struct pagevec pvec;
> +	pgoff_t index = 0;
> +	pgoff_t end = MAX_BLKADDR(sbi);
> +
> +	pagevec_init(&pvec);
> +
> +	do {
> +		unsigned int nr_pages;
> +		int i;
> +
> +		nr_pages = pagevec_lookup_range(&pvec, mapping,
> +						&index, end - 1);
> +		if (!nr_pages)
> +			break;
> +
> +		for (i = 0; i < nr_pages; i++) {
> +			struct page *page = pvec.pages[i];
> +
> +			if (page->index > end)
> +				break;
> +
> +			lock_page(page);
> +			if (page->mapping != mapping) {
> +				unlock_page(page);
> +				continue;
> +			}
> +
> +			if (ino != page_private(page)) {
> +				unlock_page(page);
> +				continue;
> +			}
> +
> +			generic_error_remove_page(mapping, page);
> +			unlock_page(page);
> +		}
> +		pagevec_release(&pvec);
> +		cond_resched();
> +	} while (index < end);
> +}
> +
> +int f2fs_init_compress_inode(struct f2fs_sb_info *sbi)
> +{
> +	struct inode *inode;
> +
> +	if (!test_opt(sbi, COMPRESS_CACHE))
> +		return 0;
> +
> +	inode = f2fs_iget(sbi->sb, F2FS_COMPRESS_INO(sbi));
> +	if (IS_ERR(inode))
> +		return PTR_ERR(inode);
> +	sbi->compress_inode = inode;
> +
> +	sbi->compress_percent = COMPRESS_PERCENT;
> +	sbi->compress_watermark = COMPRESS_WATERMARK;
> +
> +	atomic_set(&sbi->compress_page_hit, 0);
> +
> +	return 0;
> +}
> +
> +void f2fs_destroy_compress_inode(struct f2fs_sb_info *sbi)
> +{
> +	if (!sbi->compress_inode)
> +		return;
> +	iput(sbi->compress_inode);
> +	sbi->compress_inode = NULL;
> +}
> +
>   int f2fs_init_page_array_cache(struct f2fs_sb_info *sbi)
>   {
>   	dev_t dev = sbi->sb->s_bdev->bd_dev;
> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> index aa34d620bec9..6787a7a03e86 100644
> --- a/fs/f2fs/data.c
> +++ b/fs/f2fs/data.c
> @@ -133,17 +133,21 @@ static void __read_end_io(struct bio *bio, bool compr, bool verity)
>   	struct page *page;
>   	struct bio_vec *bv;
>   	struct bvec_iter_all iter_all;
> +	unsigned int ofs = 0;
>   
>   	bio_for_each_segment_all(bv, bio, iter_all) {
>   		page = bv->bv_page;
>   
>   #ifdef CONFIG_F2FS_FS_COMPRESSION
>   		if (compr && f2fs_is_compressed_page(page)) {
> -			f2fs_decompress_pages(bio, page, verity);
> +			f2fs_decompress_pages(bio, page, verity, ofs);
> +			ofs++;
>   			continue;
>   		}
> -		if (verity)
> +		if (verity) {
> +			ofs++;
>   			continue;
> +		}
>   #endif
>   
>   		/* PG_error was set if any post_read step failed */
> @@ -156,6 +160,7 @@ static void __read_end_io(struct bio *bio, bool compr, bool verity)
>   		}
>   		dec_page_count(F2FS_P_SB(page), __read_io_type(page));
>   		unlock_page(page);
> +		ofs++;
>   	}
>   }
>   
> @@ -1421,9 +1426,11 @@ static int __allocate_data_block(struct dnode_of_data *dn, int seg_type)
>   	old_blkaddr = dn->data_blkaddr;
>   	f2fs_allocate_data_block(sbi, NULL, old_blkaddr, &dn->data_blkaddr,
>   				&sum, seg_type, NULL);
> -	if (GET_SEGNO(sbi, old_blkaddr) != NULL_SEGNO)
> +	if (GET_SEGNO(sbi, old_blkaddr) != NULL_SEGNO) {
>   		invalidate_mapping_pages(META_MAPPING(sbi),
>   					old_blkaddr, old_blkaddr);
> +		f2fs_invalidate_compress_page(sbi, old_blkaddr);
> +	}
>   	f2fs_update_data_blkaddr(dn, dn->data_blkaddr);
>   
>   	/*
> @@ -2261,6 +2268,22 @@ int f2fs_read_multi_pages(struct compress_ctx *cc, struct bio **bio_ret,
>   		blkaddr = data_blkaddr(dn.inode, dn.node_page,
>   						dn.ofs_in_node + i + 1);
>   
> +		f2fs_load_compressed_page(sbi, page, blkaddr);
> +		if (PageUptodate(page)) {
> +			if (!atomic_dec_return(&dic->pending_pages)) {
> +				bool verity =
> +					f2fs_need_verity(inode, start_idx);
> +
> +				f2fs_do_decompress_pages(dic, verity);
> +				if (verity) {
> +					f2fs_verify_pages(dic->rpages,
> +							dic->cluster_size);
> +					f2fs_free_dic(dic);
> +				}
> +			}
> +			continue;
> +		}
> +
>   		if (bio && (!page_is_mergeable(sbi, bio,
>   					*last_block_in_bio, blkaddr) ||
>   		    !f2fs_crypt_mergeable_bio(bio, inode, page->index, NULL))) {
> diff --git a/fs/f2fs/debug.c b/fs/f2fs/debug.c
> index 197c914119da..f1f8714066c5 100644
> --- a/fs/f2fs/debug.c
> +++ b/fs/f2fs/debug.c
> @@ -145,6 +145,12 @@ static void update_general_status(struct f2fs_sb_info *sbi)
>   		si->node_pages = NODE_MAPPING(sbi)->nrpages;
>   	if (sbi->meta_inode)
>   		si->meta_pages = META_MAPPING(sbi)->nrpages;
> +#ifdef CONFIG_F2FS_FS_COMPRESSION
> +	if (sbi->compress_inode) {
> +		si->compress_pages = COMPRESS_MAPPING(sbi)->nrpages;
> +		si->compress_page_hit = atomic_read(&sbi->compress_page_hit);
> +	}
> +#endif
>   	si->nats = NM_I(sbi)->nat_cnt[TOTAL_NAT];
>   	si->dirty_nats = NM_I(sbi)->nat_cnt[DIRTY_NAT];
>   	si->sits = MAIN_SEGS(sbi);
> @@ -299,6 +305,12 @@ static void update_mem_info(struct f2fs_sb_info *sbi)
>   		unsigned npages = META_MAPPING(sbi)->nrpages;
>   		si->page_mem += (unsigned long long)npages << PAGE_SHIFT;
>   	}
> +#ifdef CONFIG_F2FS_FS_COMPRESSION
> +	if (sbi->compress_inode) {
> +		unsigned npages = COMPRESS_MAPPING(sbi)->nrpages;
> +		si->page_mem += (unsigned long long)npages << PAGE_SHIFT;
> +	}
> +#endif
>   }
>   
>   static int stat_show(struct seq_file *s, void *v)
> @@ -461,6 +473,7 @@ static int stat_show(struct seq_file *s, void *v)
>   			"volatile IO: %4d (Max. %4d)\n",
>   			   si->inmem_pages, si->aw_cnt, si->max_aw_cnt,
>   			   si->vw_cnt, si->max_vw_cnt);
> +		seq_printf(s, "  - compress: %4d, hit:%8d\n", si->compress_pages, si->compress_page_hit);
>   		seq_printf(s, "  - nodes: %4d in %4d\n",
>   			   si->ndirty_node, si->node_pages);
>   		seq_printf(s, "  - dents: %4d in dirs:%4d (%4d)\n",
> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> index 7364d453783f..0ff8b18eda05 100644
> --- a/fs/f2fs/f2fs.h
> +++ b/fs/f2fs/f2fs.h
> @@ -97,6 +97,7 @@ extern const char *f2fs_fault_name[FAULT_MAX];
>   #define F2FS_MOUNT_DISABLE_CHECKPOINT	0x02000000
>   #define F2FS_MOUNT_NORECOVERY		0x04000000
>   #define F2FS_MOUNT_ATGC			0x08000000
> +#define F2FS_MOUNT_COMPRESS_CACHE	0x10000000
>   
>   #define F2FS_OPTION(sbi)	((sbi)->mount_opt)
>   #define clear_opt(sbi, option)	(F2FS_OPTION(sbi).opt &= ~F2FS_MOUNT_##option)
> @@ -1298,6 +1299,9 @@ enum compress_flag {
>   	COMPRESS_MAX_FLAG,
>   };
>   
> +#define	COMPRESS_WATERMARK			20
> +#define	COMPRESS_PERCENT			20
> +
>   #define COMPRESS_DATA_RESERVED_SIZE		4
>   struct compress_data {
>   	__le32 clen;			/* compressed data size */
> @@ -1571,6 +1575,11 @@ struct f2fs_sb_info {
>   #ifdef CONFIG_F2FS_FS_COMPRESSION
>   	struct kmem_cache *page_array_slab;	/* page array entry */
>   	unsigned int page_array_slab_size;	/* default page array slab size */
> +
> +	struct inode *compress_inode;		/* cache compressed blocks */
> +	unsigned int compress_percent;		/* cache page percentage */
> +	unsigned int compress_watermark;	/* cache page watermark */
> +	atomic_t compress_page_hit;		/* cache hit count */
>   #endif
>   };
>   
> @@ -3536,7 +3545,8 @@ struct f2fs_stat_info {
>   	unsigned int bimodal, avg_vblocks;
>   	int util_free, util_valid, util_invalid;
>   	int rsvd_segs, overp_segs;
> -	int dirty_count, node_pages, meta_pages;
> +	int dirty_count, node_pages, meta_pages, compress_pages;
> +	int compress_page_hit;
>   	int prefree_count, call_count, cp_count, bg_cp_count;
>   	int tot_segs, node_segs, data_segs, free_segs, free_secs;
>   	int bg_node_segs, bg_data_segs;
> @@ -3874,7 +3884,8 @@ void f2fs_compress_write_end_io(struct bio *bio, struct page *page);
>   bool f2fs_is_compress_backend_ready(struct inode *inode);
>   int f2fs_init_compress_mempool(void);
>   void f2fs_destroy_compress_mempool(void);
> -void f2fs_decompress_pages(struct bio *bio, struct page *page, bool verity);
> +void f2fs_do_decompress_pages(struct decompress_io_ctx *dic, bool verity);
> +void f2fs_decompress_pages(struct bio *bio, struct page *page, bool verity, unsigned int ofs);
>   bool f2fs_cluster_is_empty(struct compress_ctx *cc);
>   bool f2fs_cluster_can_merge_page(struct compress_ctx *cc, pgoff_t index);
>   void f2fs_compress_ctx_add_page(struct compress_ctx *cc, struct page *page);
> @@ -3893,10 +3904,19 @@ void f2fs_decompress_end_io(struct page **rpages,
>   int f2fs_init_compress_ctx(struct compress_ctx *cc);
>   void f2fs_destroy_compress_ctx(struct compress_ctx *cc);
>   void f2fs_init_compress_info(struct f2fs_sb_info *sbi);
> +int f2fs_init_compress_inode(struct f2fs_sb_info *sbi);
> +void f2fs_destroy_compress_inode(struct f2fs_sb_info *sbi);
>   int f2fs_init_page_array_cache(struct f2fs_sb_info *sbi);
>   void f2fs_destroy_page_array_cache(struct f2fs_sb_info *sbi);
>   int __init f2fs_init_compress_cache(void);
>   void f2fs_destroy_compress_cache(void);
> +struct address_space *COMPRESS_MAPPING(struct f2fs_sb_info *sbi);
> +void f2fs_invalidate_compress_page(struct f2fs_sb_info *sbi, block_t blkaddr);
> +void f2fs_cache_compressed_page(struct f2fs_sb_info *sbi, struct page *page,
> +						nid_t ino, block_t blkaddr);
> +void f2fs_load_compressed_page(struct f2fs_sb_info *sbi, struct page *page,
> +								block_t blkaddr);
> +void f2fs_invalidate_compress_pages(struct f2fs_sb_info *sbi, nid_t ino);
>   #else
>   static inline bool f2fs_is_compressed_page(struct page *page) { return false; }
>   static inline bool f2fs_is_compress_backend_ready(struct inode *inode)
> @@ -3913,10 +3933,20 @@ static inline struct page *f2fs_compress_control_page(struct page *page)
>   }
>   static inline int f2fs_init_compress_mempool(void) { return 0; }
>   static inline void f2fs_destroy_compress_mempool(void) { }
> +static inline int f2fs_init_compress_inode(struct f2fs_sb_info *sbi) { return 0; }
> +static inline void f2fs_destroy_compress_inode(struct f2fs_sb_info *sbi) { }
>   static inline int f2fs_init_page_array_cache(struct f2fs_sb_info *sbi) { return 0; }
>   static inline void f2fs_destroy_page_array_cache(struct f2fs_sb_info *sbi) { }
>   static inline int __init f2fs_init_compress_cache(void) { return 0; }
>   static inline void f2fs_destroy_compress_cache(void) { }
> +static inline void f2fs_invalidate_compress_page(struct f2fs_sb_info *sbi,
> +				block_t blkaddr) { }
> +static inline void f2fs_cache_compressed_page(struct f2fs_sb_info *sbi,
> +				struct page *page, nid_t ino, block_t blkaddr) { }
> +static inline void f2fs_load_compressed_page(struct f2fs_sb_info *sbi,
> +				struct page *page, block_t blkaddr) { }
> +static inline void f2fs_invalidate_compress_pages(struct f2fs_sb_info *sbi,
> +							nid_t ino) { }
>   #endif
>   
>   static inline void set_compress_context(struct inode *inode)
> diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
> index 3ef84e6ded41..43919a3ae6a6 100644
> --- a/fs/f2fs/gc.c
> +++ b/fs/f2fs/gc.c
> @@ -1225,6 +1225,7 @@ static int move_data_block(struct inode *inode, block_t bidx,
>   	f2fs_put_page(mpage, 1);
>   	invalidate_mapping_pages(META_MAPPING(fio.sbi),
>   				fio.old_blkaddr, fio.old_blkaddr);
> +	f2fs_invalidate_compress_page(fio.sbi, fio.old_blkaddr);
>   
>   	set_page_dirty(fio.encrypted_page);
>   	if (clear_page_dirty_for_io(fio.encrypted_page))
> diff --git a/fs/f2fs/inode.c b/fs/f2fs/inode.c
> index 349d9cb933ee..f030b9b79202 100644
> --- a/fs/f2fs/inode.c
> +++ b/fs/f2fs/inode.c
> @@ -18,6 +18,10 @@
>   
>   #include <trace/events/f2fs.h>
>   
> +#ifdef CONFIG_F2FS_FS_COMPRESSION
> +extern const struct address_space_operations f2fs_compress_aops;
> +#endif
> +
>   void f2fs_mark_inode_dirty_sync(struct inode *inode, bool sync)
>   {
>   	if (is_inode_flag_set(inode, FI_NEW_INODE))
> @@ -494,6 +498,11 @@ struct inode *f2fs_iget(struct super_block *sb, unsigned long ino)
>   	if (ino == F2FS_NODE_INO(sbi) || ino == F2FS_META_INO(sbi))
>   		goto make_now;
>   
> +#ifdef CONFIG_F2FS_FS_COMPRESSION
> +	if (ino == F2FS_COMPRESS_INO(sbi))
> +		goto make_now;
> +#endif
> +
>   	ret = do_read_inode(inode);
>   	if (ret)
>   		goto bad_inode;
> @@ -504,6 +513,12 @@ struct inode *f2fs_iget(struct super_block *sb, unsigned long ino)
>   	} else if (ino == F2FS_META_INO(sbi)) {
>   		inode->i_mapping->a_ops = &f2fs_meta_aops;
>   		mapping_set_gfp_mask(inode->i_mapping, GFP_NOFS);
> +	} else if (ino == F2FS_COMPRESS_INO(sbi)) {
> +#ifdef CONFIG_F2FS_FS_COMPRESSION
> +		inode->i_mapping->a_ops = &f2fs_compress_aops;
> +#endif
> +		mapping_set_gfp_mask(inode->i_mapping,
> +			GFP_NOFS | __GFP_HIGHMEM | __GFP_MOVABLE);
>   	} else if (S_ISREG(inode->i_mode)) {
>   		inode->i_op = &f2fs_file_inode_operations;
>   		inode->i_fop = &f2fs_file_operations;
> @@ -722,8 +737,12 @@ void f2fs_evict_inode(struct inode *inode)
>   	trace_f2fs_evict_inode(inode);
>   	truncate_inode_pages_final(&inode->i_data);
>   
> +	if (test_opt(sbi, COMPRESS_CACHE) && f2fs_compressed_file(inode))
> +		f2fs_invalidate_compress_pages(sbi, inode->i_ino);
> +
>   	if (inode->i_ino == F2FS_NODE_INO(sbi) ||
> -			inode->i_ino == F2FS_META_INO(sbi))
> +			inode->i_ino == F2FS_META_INO(sbi) ||
> +			inode->i_ino == F2FS_COMPRESS_INO(sbi))
>   		goto out_clear;
>   
>   	f2fs_bug_on(sbi, get_dirty_pages(inode));
> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> index deca74cb17df..d8570b0359f5 100644
> --- a/fs/f2fs/segment.c
> +++ b/fs/f2fs/segment.c
> @@ -2305,6 +2305,7 @@ void f2fs_invalidate_blocks(struct f2fs_sb_info *sbi, block_t addr)
>   		return;
>   
>   	invalidate_mapping_pages(META_MAPPING(sbi), addr, addr);
> +	f2fs_invalidate_compress_page(sbi, addr);
>   
>   	/* add it into sit main buffer */
>   	down_write(&sit_i->sentry_lock);
> @@ -3432,9 +3433,11 @@ static void do_write_page(struct f2fs_summary *sum, struct f2fs_io_info *fio)
>   reallocate:
>   	f2fs_allocate_data_block(fio->sbi, fio->page, fio->old_blkaddr,
>   			&fio->new_blkaddr, sum, type, fio);
> -	if (GET_SEGNO(fio->sbi, fio->old_blkaddr) != NULL_SEGNO)
> +	if (GET_SEGNO(fio->sbi, fio->old_blkaddr) != NULL_SEGNO) {
>   		invalidate_mapping_pages(META_MAPPING(fio->sbi),
>   					fio->old_blkaddr, fio->old_blkaddr);
> +		f2fs_invalidate_compress_page(fio->sbi, fio->old_blkaddr);
> +	}
>   
>   	/* writeout dirty page into bdev */
>   	f2fs_submit_page_write(fio);
> @@ -3607,6 +3610,7 @@ void f2fs_do_replace_block(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
>   	if (GET_SEGNO(sbi, old_blkaddr) != NULL_SEGNO) {
>   		invalidate_mapping_pages(META_MAPPING(sbi),
>   					old_blkaddr, old_blkaddr);
> +		f2fs_invalidate_compress_page(sbi, old_blkaddr);
>   		if (!from_gc)
>   			update_segment_mtime(sbi, old_blkaddr, 0);
>   		update_sit_entry(sbi, old_blkaddr, -1);
> diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
> index 8a82721b69ef..50e749169841 100644
> --- a/fs/f2fs/super.c
> +++ b/fs/f2fs/super.c
> @@ -148,6 +148,7 @@ enum {
>   	Opt_compress_extension,
>   	Opt_compress_chksum,
>   	Opt_compress_mode,
> +	Opt_compress_cache,
>   	Opt_atgc,
>   	Opt_err,
>   };
> @@ -218,6 +219,7 @@ static match_table_t f2fs_tokens = {
>   	{Opt_compress_extension, "compress_extension=%s"},
>   	{Opt_compress_chksum, "compress_chksum"},
>   	{Opt_compress_mode, "compress_mode=%s"},
> +	{Opt_compress_cache, "compress_cache"},
>   	{Opt_atgc, "atgc"},
>   	{Opt_err, NULL},
>   };
> @@ -955,12 +957,16 @@ static int parse_options(struct super_block *sb, char *options, bool is_remount)
>   			}
>   			kfree(name);
>   			break;
> +		case Opt_compress_cache:
> +			set_opt(sbi, COMPRESS_CACHE);
> +			break;
>   #else
>   		case Opt_compress_algorithm:
>   		case Opt_compress_log_size:
>   		case Opt_compress_extension:
>   		case Opt_compress_chksum:
>   		case Opt_compress_mode:
> +		case Opt_compress_cache:
>   			f2fs_info(sbi, "compression options not supported");
>   			break;
>   #endif
> @@ -1285,6 +1291,8 @@ static void f2fs_put_super(struct super_block *sb)
>   
>   	f2fs_bug_on(sbi, sbi->fsync_node_num);
>   
> +	f2fs_destroy_compress_inode(sbi);
> +
>   	iput(sbi->node_inode);
>   	sbi->node_inode = NULL;
>   
> @@ -1554,6 +1562,9 @@ static inline void f2fs_show_compress_options(struct seq_file *seq,
>   		seq_printf(seq, ",compress_mode=%s", "fs");
>   	else if (F2FS_OPTION(sbi).compress_mode == COMPR_MODE_USER)
>   		seq_printf(seq, ",compress_mode=%s", "user");
> +
> +	if (test_opt(sbi, COMPRESS_CACHE))
> +		seq_puts(seq, ",compress_cache");
>   }
>   
>   static int f2fs_show_options(struct seq_file *seq, struct dentry *root)
> @@ -3759,10 +3770,14 @@ static int f2fs_fill_super(struct super_block *sb, void *data, int silent)
>   		goto free_node_inode;
>   	}
>   
> -	err = f2fs_register_sysfs(sbi);
> +	err = f2fs_init_compress_inode(sbi);
>   	if (err)
>   		goto free_root_inode;
>   
> +	err = f2fs_register_sysfs(sbi);
> +	if (err)
> +		goto free_compress_inode;
> +
>   #ifdef CONFIG_QUOTA
>   	/* Enable quota usage during mount */
>   	if (f2fs_sb_has_quota_ino(sbi) && !f2fs_readonly(sb)) {
> @@ -3896,6 +3911,8 @@ static int f2fs_fill_super(struct super_block *sb, void *data, int silent)
>   	/* evict some inodes being cached by GC */
>   	evict_inodes(sb);
>   	f2fs_unregister_sysfs(sbi);
> +free_compress_inode:
> +	f2fs_destroy_compress_inode(sbi);
>   free_root_inode:
>   	dput(sb->s_root);
>   	sb->s_root = NULL;
> diff --git a/include/linux/f2fs_fs.h b/include/linux/f2fs_fs.h
> index 7dc2a06cf19a..55be7afeee90 100644
> --- a/include/linux/f2fs_fs.h
> +++ b/include/linux/f2fs_fs.h
> @@ -34,6 +34,7 @@
>   #define F2FS_ROOT_INO(sbi)	((sbi)->root_ino_num)
>   #define F2FS_NODE_INO(sbi)	((sbi)->node_ino_num)
>   #define F2FS_META_INO(sbi)	((sbi)->meta_ino_num)
> +#define F2FS_COMPRESS_INO(sbi)	(NM_I(sbi)->max_nid)
>   
>   #define F2FS_MAX_QUOTAS		3
>   
>