f2fs: support data compression

This patch tries to support compression in f2fs.

- New term named cluster is defined as basic unit of compression, file can
be divided into multiple clusters logically. One cluster includes 4 << n
(n >= 0) logical pages, compression size is also cluster size, each of
cluster can be compressed or not.

- In cluster metadata layout, one special flag is used to indicate cluster
is compressed one or normal one, for compressed cluster, following metadata
maps cluster to [1, 4 << n - 1] physical blocks, in where f2fs stores
data including compress header and compressed data.

- In order to eliminate write amplification during overwrite, F2FS only
support compression on write-once file, data can be compressed only when
all logical blocks in file are valid and cluster compress ratio is lower
than specified threshold.

- To enable compression on regular inode, there are three ways:
* chattr +c file
* chattr +c dir; touch dir/file
* mount w/ -o compress_extension=ext; touch file.ext

Compress metadata layout:
[Dnode Structure]
+-----------------------------------------------+
| cluster 1 | cluster 2 | ......... | cluster N |
+-----------------------------------------------+
. . . .
. . . .
. Compressed Cluster . . Normal Cluster .
+----------+---------+---------+---------+ +---------+---------+---------+---------+
|compr flag| block 1 | block 2 | block 3 | | block 1 | block 2 | block 3 | block 4 |
+----------+---------+---------+---------+ +---------+---------+---------+---------+
. .
. .
. .
+-------------+-------------+----------+----------------------------+
| data length | data chksum | reserved | compressed data |
+-------------+-------------+----------+----------------------------+

Changelog:

20190326:
- fix error handling of read_end_io().
- remove unneeded comments in f2fs_encrypt_one_page().

20190327:
- fix wrong use of f2fs_cluster_is_full() in f2fs_mpage_readpages().
- don't jump into loop directly to avoid uninitialized variables.
- add TODO tag in error path of f2fs_write_cache_pages().

20190328:
- fix wrong merge condition in f2fs_read_multi_pages().
- check compressed file in f2fs_post_read_required().

20190401
- allow overwrite on non-compressed cluster.
- check cluster meta before writing compressed data.

20190402
- don't preallocate blocks for compressed file.

- add lz4 compress algorithm
- process multiple post read works in one workqueue
Now f2fs supports processing post read work in multiple workqueue,
it shows low performance due to schedule overhead of multiple
workqueue executing orderly.

20190921
- compress: support buffered overwrite
C: compress cluster flag
V: valid block address
N: NEW_ADDR

One cluster contain 4 blocks

before overwrite after overwrite

- VVVV -> CVNN
- CVNN -> VVVV

- CVNN -> CVNN
- CVNN -> CVVV

- CVVV -> CVNN
- CVVV -> CVVV

20191029
- add kconfig F2FS_FS_COMPRESSION to isolate compression related
codes, add kconfig F2FS_FS_{LZO,LZ4} to cover backend algorithm.
note that: will remove lzo backend if Jaegeuk agreed that too.
- update codes according to Eric's comments.

20191101
- apply fixes from Jaegeuk

20191113
- apply fixes from Jaegeuk
- split workqueue for fsverity

20191216
- apply fixes from Jaegeuk

20200117
- fix to avoid NULL pointer dereference

[Jaegeuk Kim]
- add tracepoint for f2fs_{,de}compress_pages()
- fix many bugs and add some compression stats
- fix overwrite/mmap bugs
- address 32bit build error, reported by Geert.
- bug fixes when handling errors and i_compressed_blocks

Reported-by: <[e-mail]>
Signed-off-by: Chao Yu <[e-mail]>
Signed-off-by: Jaegeuk Kim <[e-mail]>

Documentation/filesystems/f2fs.txt

···
                        hide up to all remaining free space. The actual space that
                        would be unusable can be viewed at /sys/fs/f2fs/<disk>/unusable
                        This space is reclaimed once checkpoint=enable.
+compress_algorithm=%s  Control compress algorithm, currently f2fs supports "lzo"
+                       and "lz4" algorithm.
+compress_log_size=%u   Support configuring compress cluster size, the size will
+                       be 4KB * (1 << %u), 16KB is minimum size, also it's
+                       default size.
+compress_extension=%s  Support adding specified extension, so that f2fs can enable
+                       compression on those corresponding files, e.g. if all files
+                       with '.ext' has high compression rate, we can set the '.ext'
+                       on compression extension list and enable compression on
+                       these file by default rather than to enable it via ioctl.
+                       For other files, we can still enable compression via ioctl.
 
 ================================================================================
 DEBUGFS ENTRIES
···
  4. address = fibmap(fd, offset)
  5. open(blkdev)
  6. write(blkdev, address)
+
+Compression implementation
+--------------------------
+
+- New term named cluster is defined as basic unit of compression, file can
+be divided into multiple clusters logically. One cluster includes 4 << n
+(n >= 0) logical pages, compression size is also cluster size, each of
+cluster can be compressed or not.
+
+- In cluster metadata layout, one special block address is used to indicate
+cluster is compressed one or normal one, for compressed cluster, following
+metadata maps cluster to [1, 4 << n - 1] physical blocks, in where f2fs
+stores data including compress header and compressed data.
+
+- In order to eliminate write amplification during overwrite, F2FS only
+support compression on write-once file, data can be compressed only when
+all logical blocks in file are valid and cluster compress ratio is lower
+than specified threshold.
+
+- To enable compression on regular inode, there are three ways:
+* chattr +c file
+* chattr +c dir; touch dir/file
+* mount w/ -o compress_extension=ext; touch file.ext
+
+Compress metadata layout:
+                             [Dnode Structure]
+             +-----------------------------------------------+
+             | cluster 1 | cluster 2 | ......... | cluster N |
+             +-----------------------------------------------+
+             .           .                       .           .
+       .                       .                .                      .
+  .         Compressed Cluster       .        .        Normal Cluster            .
++----------+---------+---------+---------+  +---------+---------+---------+---------+
+|compr flag| block 1 | block 2 | block 3 |  | block 1 | block 2 | block 3 | block 4 |
++----------+---------+---------+---------+  +---------+---------+---------+---------+
+           .                             .
+         .                                           .
+       .                                                           .
+      +-------------+-------------+----------+----------------------------+
+      | data length | data chksum | reserved |      compressed data       |
+      +-------------+-------------+----------+----------------------------+

fs/f2fs/Kconfig

···
 	  Test F2FS to inject faults such as ENOMEM, ENOSPC, and so on.
 
 	  If unsure, say N.
+
+config F2FS_FS_COMPRESSION
+	bool "F2FS compression feature"
+	depends on F2FS_FS
+	help
+	  Enable filesystem-level compression on f2fs regular files,
+	  multiple back-end compression algorithms are supported.
+
+config F2FS_FS_LZO
+	bool "LZO compression support"
+	depends on F2FS_FS_COMPRESSION
+	select LZO_COMPRESS
+	select LZO_DECOMPRESS
+	default y
+	help
+	  Support LZO compress algorithm, if unsure, say Y.
+
+config F2FS_FS_LZ4
+	bool "LZ4 compression support"
+	depends on F2FS_FS_COMPRESSION
+	select LZ4_COMPRESS
+	select LZ4_DECOMPRESS
+	default y
+	help
+	  Support LZ4 compress algorithm, if unsure, say Y.

fs/f2fs/Makefile

···
 f2fs-$(CONFIG_F2FS_FS_POSIX_ACL) += acl.o
 f2fs-$(CONFIG_F2FS_IO_TRACE) += trace.o
 f2fs-$(CONFIG_FS_VERITY) += verity.o
+f2fs-$(CONFIG_F2FS_FS_COMPRESSION) += compress.o

fs/f2fs/compress.c

···
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * f2fs compress support
+ *
+ * Copyright (c) 2019 Chao Yu <[e-mail]>
+ */
+
+#include <linux/fs.h>
+#include <linux/f2fs_fs.h>
+#include <linux/writeback.h>
+#include <linux/backing-dev.h>
+#include <linux/lzo.h>
+#include <linux/lz4.h>
+
+#include "f2fs.h"
+#include "node.h"
+#include <trace/events/f2fs.h>
+
+struct f2fs_compress_ops {
+	int (*init_compress_ctx)(struct compress_ctx *cc);
+	void (*destroy_compress_ctx)(struct compress_ctx *cc);
+	int (*compress_pages)(struct compress_ctx *cc);
+	int (*decompress_pages)(struct decompress_io_ctx *dic);
+};
+
+static unsigned int offset_in_cluster(struct compress_ctx *cc, pgoff_t index)
+{
+	return index & (cc->cluster_size - 1);
+}
+
+static pgoff_t cluster_idx(struct compress_ctx *cc, pgoff_t index)
+{
+	return index >> cc->log_cluster_size;
+}
+
+static pgoff_t start_idx_of_cluster(struct compress_ctx *cc)
+{
+	return cc->cluster_idx << cc->log_cluster_size;
+}
+
+bool f2fs_is_compressed_page(struct page *page)
+{
+	if (!PagePrivate(page))
+		return false;
+	if (!page_private(page))
+		return false;
+	if (IS_ATOMIC_WRITTEN_PAGE(page) || IS_DUMMY_WRITTEN_PAGE(page))
+		return false;
+	f2fs_bug_on(F2FS_M_SB(page->mapping),
+		*((u32 *)page_private(page)) != F2FS_COMPRESSED_PAGE_MAGIC);
+	return true;
+}
+
+static void f2fs_set_compressed_page(struct page *page,
+		struct inode *inode, pgoff_t index, void *data, refcount_t *r)
+{
+	SetPagePrivate(page);
+	set_page_private(page, (unsigned long)data);
+
+	/* i_crypto_info and iv index */
+	page->index = index;
+	page->mapping = inode->i_mapping;
+	if (r)
+		refcount_inc(r);
+}
+
+static void f2fs_put_compressed_page(struct page *page)
+{
+	set_page_private(page, (unsigned long)NULL);
+	ClearPagePrivate(page);
+	page->mapping = NULL;
+	unlock_page(page);
+	put_page(page);
+}
+
+static void f2fs_drop_rpages(struct compress_ctx *cc, int len, bool unlock)
+{
+	int i;
+
+	for (i = 0; i < len; i++) {
+		if (!cc->rpages[i])
+			continue;
+		if (unlock)
+			unlock_page(cc->rpages[i]);
+		else
+			put_page(cc->rpages[i]);
+	}
+}
+
+static void f2fs_put_rpages(struct compress_ctx *cc)
+{
+	f2fs_drop_rpages(cc, cc->cluster_size, false);
+}
+
+static void f2fs_unlock_rpages(struct compress_ctx *cc, int len)
+{
+	f2fs_drop_rpages(cc, len, true);
+}
+
+static void f2fs_put_rpages_mapping(struct compress_ctx *cc,
+				struct address_space *mapping,
+				pgoff_t start, int len)
+{
+	int i;
+
+	for (i = 0; i < len; i++) {
+		struct page *page = find_get_page(mapping, start + i);
+
+		put_page(page);
+		put_page(page);
+	}
+}
+
+static void f2fs_put_rpages_wbc(struct compress_ctx *cc,
+		struct writeback_control *wbc, bool redirty, int unlock)
+{
+	unsigned int i;
+
+	for (i = 0; i < cc->cluster_size; i++) {
+		if (!cc->rpages[i])
+			continue;
+		if (redirty)
+			redirty_page_for_writepage(wbc, cc->rpages[i]);
+		f2fs_put_page(cc->rpages[i], unlock);
+	}
+}
+
+struct page *f2fs_compress_control_page(struct page *page)
+{
+	return ((struct compress_io_ctx *)page_private(page))->rpages[0];
+}
+
+int f2fs_init_compress_ctx(struct compress_ctx *cc)
+{
+	struct f2fs_sb_info *sbi = F2FS_I_SB(cc->inode);
+
+	if (cc->nr_rpages)
+		return 0;
+
+	cc->rpages = f2fs_kzalloc(sbi, sizeof(struct page *) <<
+					cc->log_cluster_size, GFP_NOFS);
+	return cc->rpages ? 0 : -ENOMEM;
+}
+
+void f2fs_destroy_compress_ctx(struct compress_ctx *cc)
+{
+	kfree(cc->rpages);
+	cc->rpages = NULL;
+	cc->nr_rpages = 0;
+	cc->nr_cpages = 0;
+	cc->cluster_idx = NULL_CLUSTER;
+}
+
+void f2fs_compress_ctx_add_page(struct compress_ctx *cc, struct page *page)
+{
+	unsigned int cluster_ofs;
+
+	if (!f2fs_cluster_can_merge_page(cc, page->index))
+		f2fs_bug_on(F2FS_I_SB(cc->inode), 1);
+
+	cluster_ofs = offset_in_cluster(cc, page->index);
+	cc->rpages[cluster_ofs] = page;
+	cc->nr_rpages++;
+	cc->cluster_idx = cluster_idx(cc, page->index);
+}
+
+#ifdef CONFIG_F2FS_FS_LZO
+static int lzo_init_compress_ctx(struct compress_ctx *cc)
+{
+	cc->private = f2fs_kvmalloc(F2FS_I_SB(cc->inode),
+				LZO1X_MEM_COMPRESS, GFP_NOFS);
+	if (!cc->private)
+		return -ENOMEM;
+
+	cc->clen = lzo1x_worst_compress(PAGE_SIZE << cc->log_cluster_size);
+	return 0;
+}
+
+static void lzo_destroy_compress_ctx(struct compress_ctx *cc)
+{
+	kvfree(cc->private);
+	cc->private = NULL;
+}
+
+static int lzo_compress_pages(struct compress_ctx *cc)
+{
+	int ret;
+
+	ret = lzo1x_1_compress(cc->rbuf, cc->rlen, cc->cbuf->cdata,
+					&cc->clen, cc->private);
+	if (ret != LZO_E_OK) {
+		printk_ratelimited("%sF2FS-fs (%s): lzo compress failed, ret:%d\n",
+				KERN_ERR, F2FS_I_SB(cc->inode)->sb->s_id, ret);
+		return -EIO;
+	}
+	return 0;
+}
+
+static int lzo_decompress_pages(struct decompress_io_ctx *dic)
+{
+	int ret;
+
+	ret = lzo1x_decompress_safe(dic->cbuf->cdata, dic->clen,
+						dic->rbuf, &dic->rlen);
+	if (ret != LZO_E_OK) {
+		printk_ratelimited("%sF2FS-fs (%s): lzo decompress failed, ret:%d\n",
+				KERN_ERR, F2FS_I_SB(dic->inode)->sb->s_id, ret);
+		return -EIO;
+	}
+
+	if (dic->rlen != PAGE_SIZE << dic->log_cluster_size) {
+		printk_ratelimited("%sF2FS-fs (%s): lzo invalid rlen:%zu, "
+					"expected:%lu\n", KERN_ERR,
+					F2FS_I_SB(dic->inode)->sb->s_id,
+					dic->rlen,
+					PAGE_SIZE << dic->log_cluster_size);
+		return -EIO;
+	}
+	return 0;
+}
+
+static const struct f2fs_compress_ops f2fs_lzo_ops = {
+	.init_compress_ctx	= lzo_init_compress_ctx,
+	.destroy_compress_ctx	= lzo_destroy_compress_ctx,
+	.compress_pages		= lzo_compress_pages,
+	.decompress_pages	= lzo_decompress_pages,
+};
+#endif
+
+#ifdef CONFIG_F2FS_FS_LZ4
+static int lz4_init_compress_ctx(struct compress_ctx *cc)
+{
+	cc->private = f2fs_kvmalloc(F2FS_I_SB(cc->inode),
+				LZ4_MEM_COMPRESS, GFP_NOFS);
+	if (!cc->private)
+		return -ENOMEM;
+
+	cc->clen = LZ4_compressBound(PAGE_SIZE << cc->log_cluster_size);
+	return 0;
+}
+
+static void lz4_destroy_compress_ctx(struct compress_ctx *cc)
+{
+	kvfree(cc->private);
+	cc->private = NULL;
+}
+
+static int lz4_compress_pages(struct compress_ctx *cc)
+{
+	int len;
+
+	len = LZ4_compress_default(cc->rbuf, cc->cbuf->cdata, cc->rlen,
+						cc->clen, cc->private);
+	if (!len) {
+		printk_ratelimited("%sF2FS-fs (%s): lz4 compress failed\n",
+				KERN_ERR, F2FS_I_SB(cc->inode)->sb->s_id);
+		return -EIO;
+	}
+	cc->clen = len;
+	return 0;
+}
+
+static int lz4_decompress_pages(struct decompress_io_ctx *dic)
+{
+	int ret;
+
+	ret = LZ4_decompress_safe(dic->cbuf->cdata, dic->rbuf,
+						dic->clen, dic->rlen);
+	if (ret < 0) {
+		printk_ratelimited("%sF2FS-fs (%s): lz4 decompress failed, ret:%d\n",
+				KERN_ERR, F2FS_I_SB(dic->inode)->sb->s_id, ret);
+		return -EIO;
+	}
+
+	if (ret != PAGE_SIZE << dic->log_cluster_size) {
+		printk_ratelimited("%sF2FS-fs (%s): lz4 invalid rlen:%zu, "
+					"expected:%lu\n", KERN_ERR,
+					F2FS_I_SB(dic->inode)->sb->s_id,
+					dic->rlen,
+					PAGE_SIZE << dic->log_cluster_size);
+		return -EIO;
+	}
+	return 0;
+}
+
+static const struct f2fs_compress_ops f2fs_lz4_ops = {
+	.init_compress_ctx	= lz4_init_compress_ctx,
+	.destroy_compress_ctx	= lz4_destroy_compress_ctx,
+	.compress_pages		= lz4_compress_pages,
+	.decompress_pages	= lz4_decompress_pages,
+};
+#endif
+
+static const struct f2fs_compress_ops *f2fs_cops[COMPRESS_MAX] = {
+#ifdef CONFIG_F2FS_FS_LZO
+	&f2fs_lzo_ops,
+#else
+	NULL,
+#endif
+#ifdef CONFIG_F2FS_FS_LZ4
+	&f2fs_lz4_ops,
+#else
+	NULL,
+#endif
+};
+
+bool f2fs_is_compress_backend_ready(struct inode *inode)
+{
+	if (!f2fs_compressed_file(inode))
+		return true;
+	return f2fs_cops[F2FS_I(inode)->i_compress_algorithm];
+}
+
+static struct page *f2fs_grab_page(void)
+{
+	struct page *page;
+
+	page = alloc_page(GFP_NOFS);
+	if (!page)
+		return NULL;
+	lock_page(page);
+	return page;
+}
+
+static int f2fs_compress_pages(struct compress_ctx *cc)
+{
+	struct f2fs_sb_info *sbi = F2FS_I_SB(cc->inode);
+	struct f2fs_inode_info *fi = F2FS_I(cc->inode);
+	const struct f2fs_compress_ops *cops =
+				f2fs_cops[fi->i_compress_algorithm];
+	unsigned int max_len, nr_cpages;
+	int i, ret;
+
+	trace_f2fs_compress_pages_start(cc->inode, cc->cluster_idx,
+				cc->cluster_size, fi->i_compress_algorithm);
+
+	ret = cops->init_compress_ctx(cc);
+	if (ret)
+		goto out;
+
+	max_len = COMPRESS_HEADER_SIZE + cc->clen;
+	cc->nr_cpages = DIV_ROUND_UP(max_len, PAGE_SIZE);
+
+	cc->cpages = f2fs_kzalloc(sbi, sizeof(struct page *) *
+					cc->nr_cpages, GFP_NOFS);
+	if (!cc->cpages) {
+		ret = -ENOMEM;
+		goto destroy_compress_ctx;
+	}
+
+	for (i = 0; i < cc->nr_cpages; i++) {
+		cc->cpages[i] = f2fs_grab_page();
+		if (!cc->cpages[i]) {
+			ret = -ENOMEM;
+			goto out_free_cpages;
+		}
+	}
+
+	cc->rbuf = vmap(cc->rpages, cc->cluster_size, VM_MAP, PAGE_KERNEL_RO);
+	if (!cc->rbuf) {
+		ret = -ENOMEM;
+		goto out_free_cpages;
+	}
+
+	cc->cbuf = vmap(cc->cpages, cc->nr_cpages, VM_MAP, PAGE_KERNEL);
+	if (!cc->cbuf) {
+		ret = -ENOMEM;
+		goto out_vunmap_rbuf;
+	}
+
+	ret = cops->compress_pages(cc);
+	if (ret)
+		goto out_vunmap_cbuf;
+
+	max_len = PAGE_SIZE * (cc->cluster_size - 1) - COMPRESS_HEADER_SIZE;
+
+	if (cc->clen > max_len) {
+		ret = -EAGAIN;
+		goto out_vunmap_cbuf;
+	}
+
+	cc->cbuf->clen = cpu_to_le32(cc->clen);
+	cc->cbuf->chksum = cpu_to_le32(0);
+
+	for (i = 0; i < COMPRESS_DATA_RESERVED_SIZE; i++)
+		cc->cbuf->reserved[i] = cpu_to_le32(0);
+
+	vunmap(cc->cbuf);
+	vunmap(cc->rbuf);
+
+	nr_cpages = DIV_ROUND_UP(cc->clen + COMPRESS_HEADER_SIZE, PAGE_SIZE);
+
+	for (i = nr_cpages; i < cc->nr_cpages; i++) {
+		f2fs_put_compressed_page(cc->cpages[i]);
+		cc->cpages[i] = NULL;
+	}
+
+	cc->nr_cpages = nr_cpages;
+
+	trace_f2fs_compress_pages_end(cc->inode, cc->cluster_idx,
+							cc->clen, ret);
+	return 0;
+
+out_vunmap_cbuf:
+	vunmap(cc->cbuf);
+out_vunmap_rbuf:
+	vunmap(cc->rbuf);
+out_free_cpages:
+	for (i = 0; i < cc->nr_cpages; i++) {
+		if (cc->cpages[i])
+			f2fs_put_compressed_page(cc->cpages[i]);
+	}
+	kfree(cc->cpages);
+	cc->cpages = NULL;
+destroy_compress_ctx:
+	cops->destroy_compress_ctx(cc);
+out:
+	trace_f2fs_compress_pages_end(cc->inode, cc->cluster_idx,
+							cc->clen, ret);
+	return ret;
+}
+
+void f2fs_decompress_pages(struct bio *bio, struct page *page, 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;
+
+	dec_page_count(sbi, F2FS_RD_DATA);
+
+	if (bio->bi_status || PageError(page))
+		dic->failed = true;
+
+	if (refcount_dec_not_one(&dic->ref))
+		return;
+
+	trace_f2fs_decompress_pages_start(dic->inode, dic->cluster_idx,
+				dic->cluster_size, fi->i_compress_algorithm);
+
+	/* submit partial compressed pages */
+	if (dic->failed) {
+		ret = -EIO;
+		goto out_free_dic;
+	}
+
+	dic->rbuf = vmap(dic->tpages, dic->cluster_size, VM_MAP, PAGE_KERNEL);
+	if (!dic->rbuf) {
+		ret = -ENOMEM;
+		goto out_free_dic;
+	}
+
+	dic->cbuf = vmap(dic->cpages, dic->nr_cpages, VM_MAP, PAGE_KERNEL_RO);
+	if (!dic->cbuf) {
+		ret = -ENOMEM;
+		goto out_vunmap_rbuf;
+	}
+
+	dic->clen = le32_to_cpu(dic->cbuf->clen);
+	dic->rlen = PAGE_SIZE << dic->log_cluster_size;
+
+	if (dic->clen > PAGE_SIZE * dic->nr_cpages - COMPRESS_HEADER_SIZE) {
+		ret = -EFSCORRUPTED;
+		goto out_vunmap_cbuf;
+	}
+
+	ret = cops->decompress_pages(dic);
+
+out_vunmap_cbuf:
+	vunmap(dic->cbuf);
+out_vunmap_rbuf:
+	vunmap(dic->rbuf);
+out_free_dic:
+	if (!verity)
+		f2fs_decompress_end_io(dic->rpages, dic->cluster_size,
+								ret, false);
+
+	trace_f2fs_decompress_pages_end(dic->inode, dic->cluster_idx,
+							dic->clen, ret);
+	if (!verity)
+		f2fs_free_dic(dic);
+}
+
+static bool is_page_in_cluster(struct compress_ctx *cc, pgoff_t index)
+{
+	if (cc->cluster_idx == NULL_CLUSTER)
+		return true;
+	return cc->cluster_idx == cluster_idx(cc, index);
+}
+
+bool f2fs_cluster_is_empty(struct compress_ctx *cc)
+{
+	return cc->nr_rpages == 0;
+}
+
+static bool f2fs_cluster_is_full(struct compress_ctx *cc)
+{
+	return cc->cluster_size == cc->nr_rpages;
+}
+
+bool f2fs_cluster_can_merge_page(struct compress_ctx *cc, pgoff_t index)
+{
+	if (f2fs_cluster_is_empty(cc))
+		return true;
+	return is_page_in_cluster(cc, index);
+}
+
+static bool __cluster_may_compress(struct compress_ctx *cc)
+{
+	struct f2fs_sb_info *sbi = F2FS_I_SB(cc->inode);
+	loff_t i_size = i_size_read(cc->inode);
+	unsigned nr_pages = DIV_ROUND_UP(i_size, PAGE_SIZE);
+	int i;
+
+	for (i = 0; i < cc->cluster_size; i++) {
+		struct page *page = cc->rpages[i];
+
+		f2fs_bug_on(sbi, !page);
+
+		if (unlikely(f2fs_cp_error(sbi)))
+			return false;
+		if (unlikely(is_sbi_flag_set(sbi, SBI_POR_DOING)))
+			return false;
+
+		/* beyond EOF */
+		if (page->index >= nr_pages)
+			return false;
+	}
+	return true;
+}
+
+/* return # of compressed block addresses */
+static int f2fs_compressed_blocks(struct compress_ctx *cc)
+{
+	struct dnode_of_data dn;
+	int ret;
+
+	set_new_dnode(&dn, cc->inode, NULL, NULL, 0);
+	ret = f2fs_get_dnode_of_data(&dn, start_idx_of_cluster(cc),
+							LOOKUP_NODE);
+	if (ret) {
+		if (ret == -ENOENT)
+			ret = 0;
+		goto fail;
+	}
+
+	if (dn.data_blkaddr == COMPRESS_ADDR) {
+		int i;
+
+		ret = 1;
+		for (i = 1; i < cc->cluster_size; i++) {
+			block_t blkaddr;
+
+			blkaddr = datablock_addr(dn.inode,
+					dn.node_page, dn.ofs_in_node + i);
+			if (blkaddr != NULL_ADDR)
+				ret++;
+		}
+	}
+fail:
+	f2fs_put_dnode(&dn);
+	return ret;
+}
+
+int f2fs_is_compressed_cluster(struct inode *inode, pgoff_t index)
+{
+	struct compress_ctx cc = {
+		.inode = inode,
+		.log_cluster_size = F2FS_I(inode)->i_log_cluster_size,
+		.cluster_size = F2FS_I(inode)->i_cluster_size,
+		.cluster_idx = index >> F2FS_I(inode)->i_log_cluster_size,
+	};
+
+	return f2fs_compressed_blocks(&cc);
+}
+
+static bool cluster_may_compress(struct compress_ctx *cc)
+{
+	if (!f2fs_compressed_file(cc->inode))
+		return false;
+	if (f2fs_is_atomic_file(cc->inode))
+		return false;
+	if (f2fs_is_mmap_file(cc->inode))
+		return false;
+	if (!f2fs_cluster_is_full(cc))
+		return false;
+	return __cluster_may_compress(cc);
+}
+
+static void set_cluster_writeback(struct compress_ctx *cc)
+{
+	int i;
+
+	for (i = 0; i < cc->cluster_size; i++) {
+		if (cc->rpages[i])
+			set_page_writeback(cc->rpages[i]);
+	}
+}
+
+static void set_cluster_dirty(struct compress_ctx *cc)
+{
+	int i;
+
+	for (i = 0; i < cc->cluster_size; i++)
+		if (cc->rpages[i])
+			set_page_dirty(cc->rpages[i]);
+}
+
+static int prepare_compress_overwrite(struct compress_ctx *cc,
+		struct page **pagep, pgoff_t index, void **fsdata)
+{
+	struct f2fs_sb_info *sbi = F2FS_I_SB(cc->inode);
+	struct address_space *mapping = cc->inode->i_mapping;
+	struct page *page;
+	struct dnode_of_data dn;
+	sector_t last_block_in_bio;
+	unsigned fgp_flag = FGP_LOCK | FGP_WRITE | FGP_CREAT;
+	pgoff_t start_idx = start_idx_of_cluster(cc);
+	int i, ret;
+	bool prealloc;
+
+retry:
+	ret = f2fs_compressed_blocks(cc);
+	if (ret <= 0)
+		return ret;
+
+	/* compressed case */
+	prealloc = (ret < cc->cluster_size);
+
+	ret = f2fs_init_compress_ctx(cc);
+	if (ret)
+		return ret;
+
+	/* keep page reference to avoid page reclaim */
+	for (i = 0; i < cc->cluster_size; i++) {
+		page = f2fs_pagecache_get_page(mapping, start_idx + i,
+							fgp_flag, GFP_NOFS);
+		if (!page) {
+			ret = -ENOMEM;
+			goto unlock_pages;
+		}
+
+		if (PageUptodate(page))
+			unlock_page(page);
+		else
+			f2fs_compress_ctx_add_page(cc, page);
+	}
+
+	if (!f2fs_cluster_is_empty(cc)) {
+		struct bio *bio = NULL;
+
+		ret = f2fs_read_multi_pages(cc, &bio, cc->cluster_size,
+						&last_block_in_bio, false);
+		f2fs_destroy_compress_ctx(cc);
+		if (ret)
+			goto release_pages;
+		if (bio)
+			f2fs_submit_bio(sbi, bio, DATA);
+
+		ret = f2fs_init_compress_ctx(cc);
+		if (ret)
+			goto release_pages;
+	}
+
+	for (i = 0; i < cc->cluster_size; i++) {
+		f2fs_bug_on(sbi, cc->rpages[i]);
+
+		page = find_lock_page(mapping, start_idx + i);
+		f2fs_bug_on(sbi, !page);
+
+		f2fs_wait_on_page_writeback(page, DATA, true, true);
+
+		f2fs_compress_ctx_add_page(cc, page);
+		f2fs_put_page(page, 0);
+
+		if (!PageUptodate(page)) {
+			f2fs_unlock_rpages(cc, i + 1);
+			f2fs_put_rpages_mapping(cc, mapping, start_idx,
+					cc->cluster_size);
+			f2fs_destroy_compress_ctx(cc);
+			goto retry;
+		}
+	}
+
+	if (prealloc) {
+		__do_map_lock(sbi, F2FS_GET_BLOCK_PRE_AIO, true);
+
+		set_new_dnode(&dn, cc->inode, NULL, NULL, 0);
+
+		for (i = cc->cluster_size - 1; i > 0; i--) {
+			ret = f2fs_get_block(&dn, start_idx + i);
+			if (ret) {
+				i = cc->cluster_size;
+				break;
+			}
+
+			if (dn.data_blkaddr != NEW_ADDR)
+				break;
+		}
+
+		__do_map_lock(sbi, F2FS_GET_BLOCK_PRE_AIO, false);
+	}
+
+	if (likely(!ret)) {
+		*fsdata = cc->rpages;
+		*pagep = cc->rpages[offset_in_cluster(cc, index)];
+		return cc->cluster_size;
+	}
+
+unlock_pages:
+	f2fs_unlock_rpages(cc, i);
+release_pages:
+	f2fs_put_rpages_mapping(cc, mapping, start_idx, i);
+	f2fs_destroy_compress_ctx(cc);
+	return ret;
+}
+
+int f2fs_prepare_compress_overwrite(struct inode *inode,
+		struct page **pagep, pgoff_t index, void **fsdata)
+{
+	struct compress_ctx cc = {
+		.inode = inode,
+		.log_cluster_size = F2FS_I(inode)->i_log_cluster_size,
+		.cluster_size = F2FS_I(inode)->i_cluster_size,
+		.cluster_idx = index >> F2FS_I(inode)->i_log_cluster_size,
+		.rpages = NULL,
+		.nr_rpages = 0,
+	};
+
+	return prepare_compress_overwrite(&cc, pagep, index, fsdata);
+}
+
+bool f2fs_compress_write_end(struct inode *inode, void *fsdata,
+					pgoff_t index, unsigned copied)
+
+{
+	struct compress_ctx cc = {
+		.log_cluster_size = F2FS_I(inode)->i_log_cluster_size,
+		.cluster_size = F2FS_I(inode)->i_cluster_size,
+		.rpages = fsdata,
+	};
+	bool first_index = (index == cc.rpages[0]->index);
+
+	if (copied)
+		set_cluster_dirty(&cc);
+
+	f2fs_put_rpages_wbc(&cc, NULL, false, 1);
+	f2fs_destroy_compress_ctx(&cc);
+
+	return first_index;
+}
+
+static int f2fs_write_compressed_pages(struct compress_ctx *cc,
+					int *submitted,
+					struct writeback_control *wbc,
+					enum iostat_type io_type)
+{
+	struct inode *inode = cc->inode;
+	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
+	struct f2fs_inode_info *fi = F2FS_I(inode);
+	struct f2fs_io_info fio = {
+		.sbi = sbi,
+		.ino = cc->inode->i_ino,
+		.type = DATA,
+		.op = REQ_OP_WRITE,
+		.op_flags = wbc_to_write_flags(wbc),
+		.old_blkaddr = NEW_ADDR,
+		.page = NULL,
+		.encrypted_page = NULL,
+		.compressed_page = NULL,
+		.submitted = false,
+		.need_lock = LOCK_RETRY,
+		.io_type = io_type,
+		.io_wbc = wbc,
+		.encrypted = f2fs_encrypted_file(cc->inode),
+	};
+	struct dnode_of_data dn;
+	struct node_info ni;
+	struct compress_io_ctx *cic;
+	pgoff_t start_idx = start_idx_of_cluster(cc);
+	unsigned int last_index = cc->cluster_size - 1;
+	loff_t psize;
+	int i, err;
+
+	set_new_dnode(&dn, cc->inode, NULL, NULL, 0);
+
+	f2fs_lock_op(sbi);
+
+	err = f2fs_get_dnode_of_data(&dn, start_idx, LOOKUP_NODE);
+	if (err)
+		goto out_unlock_op;
+
+	for (i = 0; i < cc->cluster_size; i++) {
+		if (datablock_addr(dn.inode, dn.node_page,
+					dn.ofs_in_node + i) == NULL_ADDR)
+			goto out_put_dnode;
+	}
+
+	psize = (loff_t)(cc->rpages[last_index]->index + 1) << PAGE_SHIFT;
+
+	err = f2fs_get_node_info(fio.sbi, dn.nid, &ni);
+	if (err)
+		goto out_put_dnode;
+
+	fio.version = ni.version;
+
+	cic = f2fs_kzalloc(sbi, sizeof(struct compress_io_ctx), GFP_NOFS);
+	if (!cic)
+		goto out_put_dnode;
+
+	cic->magic = F2FS_COMPRESSED_PAGE_MAGIC;
+	cic->inode = inode;
+	refcount_set(&cic->ref, 1);
+	cic->rpages = f2fs_kzalloc(sbi, sizeof(struct page *) <<
+			cc->log_cluster_size, GFP_NOFS);
+	if (!cic->rpages)
+		goto out_put_cic;
+
+	cic->nr_rpages = cc->cluster_size;
+
+	for (i = 0; i < cc->nr_cpages; i++) {
+		f2fs_set_compressed_page(cc->cpages[i], inode,
+					cc->rpages[i + 1]->index,
+					cic, i ? &cic->ref : NULL);
+		fio.compressed_page = cc->cpages[i];
+		if (fio.encrypted) {
+			fio.page = cc->rpages[i + 1];
+			err = f2fs_encrypt_one_page(&fio);
+			if (err)
+				goto out_destroy_crypt;
+			cc->cpages[i] = fio.encrypted_page;
+		}
+	}
+
+	set_cluster_writeback(cc);
+
+	for (i = 0; i < cc->cluster_size; i++)
+		cic->rpages[i] = cc->rpages[i];
+
+	for (i = 0; i < cc->cluster_size; i++, dn.ofs_in_node++) {
+		block_t blkaddr;
+
+		blkaddr = datablock_addr(dn.inode, dn.node_page,
+							dn.ofs_in_node);
+		fio.page = cic->rpages[i];
+		fio.old_blkaddr = blkaddr;
+
+		/* cluster header */
+		if (i == 0) {
+			if (blkaddr == COMPRESS_ADDR)
+				fio.compr_blocks++;
+			if (__is_valid_data_blkaddr(blkaddr))
+				f2fs_invalidate_blocks(sbi, blkaddr);
+			f2fs_update_data_blkaddr(&dn, COMPRESS_ADDR);
+			goto unlock_continue;
+		}
+
+		if (fio.compr_blocks && __is_valid_data_blkaddr(blkaddr))
+			fio.compr_blocks++;
+
+		if (i > cc->nr_cpages) {
+			if (__is_valid_data_blkaddr(blkaddr)) {
+				f2fs_invalidate_blocks(sbi, blkaddr);
+				f2fs_update_data_blkaddr(&dn, NEW_ADDR);
+			}
+			goto unlock_continue;
+		}
+
+		f2fs_bug_on(fio.sbi, blkaddr == NULL_ADDR);
+
+		if (fio.encrypted)
+			fio.encrypted_page = cc->cpages[i - 1];
+		else
+			fio.compressed_page = cc->cpages[i - 1];
+
+		cc->cpages[i - 1] = NULL;
+		f2fs_outplace_write_data(&dn, &fio);
+		(*submitted)++;
+unlock_continue:
+		inode_dec_dirty_pages(cc->inode);
+		unlock_page(fio.page);
+	}
+
+	if (fio.compr_blocks)
+		f2fs_i_compr_blocks_update(inode, fio.compr_blocks - 1, false);
+	f2fs_i_compr_blocks_update(inode, cc->nr_cpages, true);
+
+	set_inode_flag(cc->inode, FI_APPEND_WRITE);
+	if (cc->cluster_idx == 0)
+		set_inode_flag(inode, FI_FIRST_BLOCK_WRITTEN);
+
+	f2fs_put_dnode(&dn);
+	f2fs_unlock_op(sbi);
+
+	down_write(&fi->i_sem);
+	if (fi->last_disk_size < psize)
+		fi->last_disk_size = psize;
+	up_write(&fi->i_sem);
+
+	f2fs_put_rpages(cc);
+	f2fs_destroy_compress_ctx(cc);
+	return 0;
+
+out_destroy_crypt:
+	kfree(cic->rpages);
+
+	for (--i; i >= 0; i--)
+		fscrypt_finalize_bounce_page(&cc->cpages[i]);
+	for (i = 0; i < cc->nr_cpages; i++) {
+		if (!cc->cpages[i])
+			continue;
+		f2fs_put_page(cc->cpages[i], 1);
+	}
+out_put_cic:
+	kfree(cic);
+out_put_dnode:
+	f2fs_put_dnode(&dn);
+out_unlock_op:
+	f2fs_unlock_op(sbi);
+	return -EAGAIN;
+}
+
+void f2fs_compress_write_end_io(struct bio *bio, struct page *page)
+{
+	struct f2fs_sb_info *sbi = bio->bi_private;
+	struct compress_io_ctx *cic =
+			(struct compress_io_ctx *)page_private(page);
+	int i;
+
+	if (unlikely(bio->bi_status))
+		mapping_set_error(cic->inode->i_mapping, -EIO);
+
+	f2fs_put_compressed_page(page);
+
+	dec_page_count(sbi, F2FS_WB_DATA);
+
+	if (refcount_dec_not_one(&cic->ref))
+		return;
+
+	for (i = 0; i < cic->nr_rpages; i++) {
+		WARN_ON(!cic->rpages[i]);
+		clear_cold_data(cic->rpages[i]);
+		end_page_writeback(cic->rpages[i]);
+	}
+
+	kfree(cic->rpages);
+	kfree(cic);
+}
+
+static int f2fs_write_raw_pages(struct compress_ctx *cc,
+					int *submitted,
+					struct writeback_control *wbc,
+					enum iostat_type io_type)
+{
+	struct address_space *mapping = cc->inode->i_mapping;
+	int _submitted, compr_blocks, ret;
+	int i = -1, err = 0;
+
+	compr_blocks = f2fs_compressed_blocks(cc);
+	if (compr_blocks < 0) {
+		err = compr_blocks;
+		goto out_err;
+	}
+
+	for (i = 0; i < cc->cluster_size; i++) {
+		if (!cc->rpages[i])
+			continue;
+retry_write:
+		if (cc->rpages[i]->mapping != mapping) {
+			unlock_page(cc->rpages[i]);
+			continue;
+		}
+
+		BUG_ON(!PageLocked(cc->rpages[i]));
+
+		ret = f2fs_write_single_data_page(cc->rpages[i], &_submitted,
+						NULL, NULL, wbc, io_type,
+						compr_blocks);
+		if (ret) {
+			if (ret == AOP_WRITEPAGE_ACTIVATE) {
+				unlock_page(cc->rpages[i]);
+				ret = 0;
+			} else if (ret == -EAGAIN) {
+				ret = 0;
+				cond_resched();
+				congestion_wait(BLK_RW_ASYNC, HZ/50);
+				lock_page(cc->rpages[i]);
+				clear_page_dirty_for_io(cc->rpages[i]);
+				goto retry_write;
+			}
+			err = ret;
+			goto out_fail;
+		}
+
+		*submitted += _submitted;
+	}
+	return 0;
+
+out_fail:
+	/* TODO: revoke partially updated block addresses */
+	BUG_ON(compr_blocks);
+out_err:
+	for (++i; i < cc->cluster_size; i++) {
+		if (!cc->rpages[i])
+			continue;
+		redirty_page_for_writepage(wbc, cc->rpages[i]);
+		unlock_page(cc->rpages[i]);
+	}
+	return err;
+}
+
+int f2fs_write_multi_pages(struct compress_ctx *cc,
+					int *submitted,
+					struct writeback_control *wbc,
+					enum iostat_type io_type)
+{
+	struct f2fs_inode_info *fi = F2FS_I(cc->inode);
+	const struct f2fs_compress_ops *cops =
+			f2fs_cops[fi->i_compress_algorithm];
+	int err;
+
+	*submitted = 0;
+	if (cluster_may_compress(cc)) {
+		err = f2fs_compress_pages(cc);
+		if (err == -EAGAIN) {
+			goto write;
+		} else if (err) {
+			f2fs_put_rpages_wbc(cc, wbc, true, 1);
+			goto destroy_out;
+		}
+
+		err = f2fs_write_compressed_pages(cc, submitted,
+							wbc, io_type);
+		cops->destroy_compress_ctx(cc);
+		if (!err)
+			return 0;
+		f2fs_bug_on(F2FS_I_SB(cc->inode), err != -EAGAIN);
+	}
+write:
+	f2fs_bug_on(F2FS_I_SB(cc->inode), *submitted);
+
+	err = f2fs_write_raw_pages(cc, submitted, wbc, io_type);
+	f2fs_put_rpages_wbc(cc, wbc, false, 0);
+destroy_out:
+	f2fs_destroy_compress_ctx(cc);
+	return err;
+}
+
+struct decompress_io_ctx *f2fs_alloc_dic(struct compress_ctx *cc)
+{
+	struct f2fs_sb_info *sbi = F2FS_I_SB(cc->inode);
+	struct decompress_io_ctx *dic;
+	pgoff_t start_idx = start_idx_of_cluster(cc);
+	int i;
+
+	dic = f2fs_kzalloc(sbi, sizeof(struct decompress_io_ctx), GFP_NOFS);
+	if (!dic)
+		return ERR_PTR(-ENOMEM);
+
+	dic->rpages = f2fs_kzalloc(sbi, sizeof(struct page *) <<
+			cc->log_cluster_size, GFP_NOFS);
+	if (!dic->rpages) {
+		kfree(dic);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	dic->magic = F2FS_COMPRESSED_PAGE_MAGIC;
+	dic->inode = cc->inode;
+	refcount_set(&dic->ref, 1);
+	dic->cluster_idx = cc->cluster_idx;
+	dic->cluster_size = cc->cluster_size;
+	dic->log_cluster_size = cc->log_cluster_size;
+	dic->nr_cpages = cc->nr_cpages;
+	dic->failed = false;
+
+	for (i = 0; i < dic->cluster_size; i++)
+		dic->rpages[i] = cc->rpages[i];
+	dic->nr_rpages = cc->cluster_size;
+
+	dic->cpages = f2fs_kzalloc(sbi, sizeof(struct page *) *
+					dic->nr_cpages, GFP_NOFS);
+	if (!dic->cpages)
+		goto out_free;
+
+	for (i = 0; i < dic->nr_cpages; i++) {
+		struct page *page;
+
+		page = f2fs_grab_page();
+		if (!page)
+			goto out_free;
+
+		f2fs_set_compressed_page(page, cc->inode,
+					start_idx + i + 1,
+					dic, i ? &dic->ref : NULL);
+		dic->cpages[i] = page;
+	}
+
+	dic->tpages = f2fs_kzalloc(sbi, sizeof(struct page *) *
+					dic->cluster_size, GFP_NOFS);
+	if (!dic->tpages)
+		goto out_free;
+
+	for (i = 0; i < dic->cluster_size; i++) {
+		if (cc->rpages[i])
+			continue;
+
+		dic->tpages[i] = f2fs_grab_page();
+		if (!dic->tpages[i])
+			goto out_free;
+	}
+
+	for (i = 0; i < dic->cluster_size; i++) {
+		if (dic->tpages[i])
+			continue;
+		dic->tpages[i] = cc->rpages[i];
+	}
+
+	return dic;
+
+out_free:
+	f2fs_free_dic(dic);
+	return ERR_PTR(-ENOMEM);
+}
+
+void f2fs_free_dic(struct decompress_io_ctx *dic)
+{
+	int i;
+
+	if (dic->tpages) {
+		for (i = 0; i < dic->cluster_size; i++) {
+			if (dic->rpages[i])
+				continue;
+			f2fs_put_page(dic->tpages[i], 1);
+		}
+		kfree(dic->tpages);
+	}
+
+	if (dic->cpages) {
+		for (i = 0; i < dic->nr_cpages; i++) {
+			if (!dic->cpages[i])
+				continue;
+			f2fs_put_compressed_page(dic->cpages[i]);
+		}
+		kfree(dic->cpages);
+	}
+
+	kfree(dic->rpages);
+	kfree(dic);
+}
+
+void f2fs_decompress_end_io(struct page **rpages,
+			unsigned int cluster_size, bool err, bool verity)
+{
+	int i;
+
+	for (i = 0; i < cluster_size; i++) {
+		struct page *rpage = rpages[i];
+
+		if (!rpage)
+			continue;
+
+		if (err || PageError(rpage)) {
+			ClearPageUptodate(rpage);
+			ClearPageError(rpage);
+		} else {
+			if (!verity || fsverity_verify_page(rpage))
+				SetPageUptodate(rpage);
+			else
+				SetPageError(rpage);
+		}
+		unlock_page(rpage);
+	}
+}

fs/f2fs/data.c

···
 	if (!mapping)
 		return false;
 
+	if (f2fs_is_compressed_page(page))
+		return false;
+
 	inode = mapping->host;
 	sbi = F2FS_I_SB(inode);
 
···
 
 /* postprocessing steps for read bios */
 enum bio_post_read_step {
-	STEP_INITIAL = 0,
 	STEP_DECRYPT,
+	STEP_DECOMPRESS,
 	STEP_VERITY,
 };
 
 struct bio_post_read_ctx {
 	struct bio *bio;
+	struct f2fs_sb_info *sbi;
 	struct work_struct work;
-	unsigned int cur_step;
 	unsigned int enabled_steps;
 };
 
-static void __read_end_io(struct bio *bio)
+static void __read_end_io(struct bio *bio, bool compr, bool verity)
 {
 	struct page *page;
 	struct bio_vec *bv;
···
 
 	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);
+			continue;
+		}
+#endif
 
 		/* PG_error was set if any post_read step failed */
 		if (bio->bi_status || PageError(page)) {
···
 		dec_page_count(F2FS_P_SB(page), __read_io_type(page));
 		unlock_page(page);
 	}
-	if (bio->bi_private)
-		mempool_free(bio->bi_private, bio_post_read_ctx_pool);
-	bio_put(bio);
+}
+
+static void f2fs_release_read_bio(struct bio *bio);
+static void __f2fs_read_end_io(struct bio *bio, bool compr, bool verity)
+{
+	if (!compr)
+		__read_end_io(bio, false, verity);
+	f2fs_release_read_bio(bio);
+}
+
+static void f2fs_decompress_bio(struct bio *bio, bool verity)
+{
+	__read_end_io(bio, true, verity);
 }
 
 static void bio_post_read_processing(struct bio_post_read_ctx *ctx);
 
-static void decrypt_work(struct work_struct *work)
+static void f2fs_decrypt_work(struct bio_post_read_ctx *ctx)
 {
-	struct bio_post_read_ctx *ctx =
-		container_of(work, struct bio_post_read_ctx, work);
-
 	fscrypt_decrypt_bio(ctx->bio);
-
-	bio_post_read_processing(ctx);
 }
 
-static void verity_work(struct work_struct *work)
+static void f2fs_decompress_work(struct bio_post_read_ctx *ctx)
+{
+	f2fs_decompress_bio(ctx->bio, ctx->enabled_steps & (1 << STEP_VERITY));
+}
+
+#ifdef CONFIG_F2FS_FS_COMPRESSION
+static void f2fs_verify_pages(struct page **rpages, unsigned int cluster_size)
+{
+	f2fs_decompress_end_io(rpages, cluster_size, false, true);
+}
+
+static void f2fs_verify_bio(struct bio *bio)
+{
+	struct page *page = bio_first_page_all(bio);
+	struct decompress_io_ctx *dic =
+			(struct decompress_io_ctx *)page_private(page);
+
+	f2fs_verify_pages(dic->rpages, dic->cluster_size);
+	f2fs_free_dic(dic);
+}
+#endif
+
+static void f2fs_verity_work(struct work_struct *work)
 {
 	struct bio_post_read_ctx *ctx =
 		container_of(work, struct bio_post_read_ctx, work);
 
-	fsverity_verify_bio(ctx->bio);
+#ifdef CONFIG_F2FS_FS_COMPRESSION
+	/* previous step is decompression */
+	if (ctx->enabled_steps & (1 << STEP_DECOMPRESS)) {
 
-	bio_post_read_processing(ctx);
+		f2fs_verify_bio(ctx->bio);
+		f2fs_release_read_bio(ctx->bio);
+		return;
+	}
+#endif
+
+	fsverity_verify_bio(ctx->bio);
+	__f2fs_read_end_io(ctx->bio, false, false);
+}
+
+static void f2fs_post_read_work(struct work_struct *work)
+{
+	struct bio_post_read_ctx *ctx =
+		container_of(work, struct bio_post_read_ctx, work);
+
+	if (ctx->enabled_steps & (1 << STEP_DECRYPT))
+		f2fs_decrypt_work(ctx);
+
+	if (ctx->enabled_steps & (1 << STEP_DECOMPRESS))
+		f2fs_decompress_work(ctx);
+
+	if (ctx->enabled_steps & (1 << STEP_VERITY)) {
+		INIT_WORK(&ctx->work, f2fs_verity_work);
+		fsverity_enqueue_verify_work(&ctx->work);
+		return;
+	}
+
+	__f2fs_read_end_io(ctx->bio,
+		ctx->enabled_steps & (1 << STEP_DECOMPRESS), false);
+}
+
+static void f2fs_enqueue_post_read_work(struct f2fs_sb_info *sbi,
+						struct work_struct *work)
+{
+	queue_work(sbi->post_read_wq, work);
 }
 
 static void bio_post_read_processing(struct bio_post_read_ctx *ctx)
···
 	 * verity may require reading metadata pages that need decryption, and
 	 * we shouldn't recurse to the same workqueue.
 	 */
-	switch (++ctx->cur_step) {
-	case STEP_DECRYPT:
-		if (ctx->enabled_steps & (1 << STEP_DECRYPT)) {
-			INIT_WORK(&ctx->work, decrypt_work);
-			fscrypt_enqueue_decrypt_work(&ctx->work);
-			return;
-		}
-		ctx->cur_step++;
-		/* fall-through */
-	case STEP_VERITY:
-		if (ctx->enabled_steps & (1 << STEP_VERITY)) {
-			INIT_WORK(&ctx->work, verity_work);
-			fsverity_enqueue_verify_work(&ctx->work);
-			return;
-		}
-		ctx->cur_step++;
-		/* fall-through */
-	default:
-		__read_end_io(ctx->bio);
+
+	if (ctx->enabled_steps & (1 << STEP_DECRYPT) ||
+		ctx->enabled_steps & (1 << STEP_DECOMPRESS)) {
+		INIT_WORK(&ctx->work, f2fs_post_read_work);
+		f2fs_enqueue_post_read_work(ctx->sbi, &ctx->work);
+		return;
 	}
+
+	if (ctx->enabled_steps & (1 << STEP_VERITY)) {
+		INIT_WORK(&ctx->work, f2fs_verity_work);
+		fsverity_enqueue_verify_work(&ctx->work);
+		return;
+	}
+
+	__f2fs_read_end_io(ctx->bio, false, false);
 }
 
 static bool f2fs_bio_post_read_required(struct bio *bio)
 {
-	return bio->bi_private && !bio->bi_status;
+	return bio->bi_private;
 }
 
 static void f2fs_read_end_io(struct bio *bio)
···
 	if (f2fs_bio_post_read_required(bio)) {
 		struct bio_post_read_ctx *ctx = bio->bi_private;
 
-		ctx->cur_step = STEP_INITIAL;
 		bio_post_read_processing(ctx);
 		return;
 	}
 
-	__read_end_io(bio);
+	__f2fs_read_end_io(bio, false, false);
 }
 
 static void f2fs_write_end_io(struct bio *bio)
···
 		}
 
 		fscrypt_finalize_bounce_page(&page);
+
+#ifdef CONFIG_F2FS_FS_COMPRESSION
+		if (f2fs_is_compressed_page(page)) {
+			f2fs_compress_write_end_io(bio, page);
+			continue;
+		}
+#endif
 
 		if (unlikely(bio->bi_status)) {
 			mapping_set_error(page->mapping, -EIO);
···
 	submit_bio(bio);
 }
 
+void f2fs_submit_bio(struct f2fs_sb_info *sbi,
+				struct bio *bio, enum page_type type)
+{
+	__submit_bio(sbi, bio, type);
+}
+
 static void __submit_merged_bio(struct f2fs_bio_info *io)
 {
 	struct f2fs_io_info *fio = &io->fio;
···
 						struct page *page, nid_t ino)
 {
 	struct bio_vec *bvec;
-	struct page *target;
 	struct bvec_iter_all iter_all;
 
 	if (!bio)
···
 		return true;
 
 	bio_for_each_segment_all(bvec, bio, iter_all) {
+		struct page *target = bvec->bv_page;
 
-		target = bvec->bv_page;
-		if (fscrypt_is_bounce_page(target))
+		if (fscrypt_is_bounce_page(target)) {
 			target = fscrypt_pagecache_page(target);
+			if (IS_ERR(target))
+				continue;
+		}
+		if (f2fs_is_compressed_page(target)) {
+			target = f2fs_compress_control_page(target);
+			if (IS_ERR(target))
+				continue;
+		}
 
 		if (inode && inode == target->mapping->host)
 			return true;
···
 
 			found = true;
 
-			if (bio_add_page(*bio, page, PAGE_SIZE, 0) == PAGE_SIZE) {
+			if (bio_add_page(*bio, page, PAGE_SIZE, 0) ==
+							PAGE_SIZE) {
 				ret = 0;
 				break;
 			}
···
 
 	verify_fio_blkaddr(fio);
 
-	bio_page = fio->encrypted_page ? fio->encrypted_page : fio->page;
+	if (fio->encrypted_page)
+		bio_page = fio->encrypted_page;
+	else if (fio->compressed_page)
+		bio_page = fio->compressed_page;
+	else
+		bio_page = fio->page;
 
 	/* set submitted = true as a return value */
 	fio->submitted = true;
···
 
 	if (f2fs_encrypted_file(inode))
 		post_read_steps |= 1 << STEP_DECRYPT;
-
+	if (f2fs_compressed_file(inode))
+		post_read_steps |= 1 << STEP_DECOMPRESS;
 	if (f2fs_need_verity(inode, first_idx))
 		post_read_steps |= 1 << STEP_VERITY;
 
···
 			return ERR_PTR(-ENOMEM);
 		}
 		ctx->bio = bio;
+		ctx->sbi = sbi;
 		ctx->enabled_steps = post_read_steps;
 		bio->bi_private = ctx;
 	}
 
 	return bio;
+}
+
+static void f2fs_release_read_bio(struct bio *bio)
+{
+	if (bio->bi_private)
+		mempool_free(bio->bi_private, bio_post_read_ctx_pool);
+	bio_put(bio);
 }
 
 /* This can handle encryption stuffs */
···
 	return ret;
 }
 
+#ifdef CONFIG_F2FS_FS_COMPRESSION
+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)
+{
+	struct dnode_of_data dn;
+	struct inode *inode = cc->inode;
+	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
+	struct bio *bio = *bio_ret;
+	unsigned int start_idx = cc->cluster_idx << cc->log_cluster_size;
+	sector_t last_block_in_file;
+	const unsigned blkbits = inode->i_blkbits;
+	const unsigned blocksize = 1 << blkbits;
+	struct decompress_io_ctx *dic = NULL;
+	int i;
+	int ret = 0;
+
+	f2fs_bug_on(sbi, f2fs_cluster_is_empty(cc));
+
+	last_block_in_file = (i_size_read(inode) + blocksize - 1) >> blkbits;
+
+	/* get rid of pages beyond EOF */
+	for (i = 0; i < cc->cluster_size; i++) {
+		struct page *page = cc->rpages[i];
+
+		if (!page)
+			continue;
+		if ((sector_t)page->index >= last_block_in_file) {
+			zero_user_segment(page, 0, PAGE_SIZE);
+			if (!PageUptodate(page))
+				SetPageUptodate(page);
+		} else if (!PageUptodate(page)) {
+			continue;
+		}
+		unlock_page(page);
+		cc->rpages[i] = NULL;
+		cc->nr_rpages--;
+	}
+
+	/* we are done since all pages are beyond EOF */
+	if (f2fs_cluster_is_empty(cc))
+		goto out;
+
+	set_new_dnode(&dn, inode, NULL, NULL, 0);
+	ret = f2fs_get_dnode_of_data(&dn, start_idx, LOOKUP_NODE);
+	if (ret)
+		goto out;
+
+	/* cluster was overwritten as normal cluster */
+	if (dn.data_blkaddr != COMPRESS_ADDR)
+		goto out;
+
+	for (i = 1; i < cc->cluster_size; i++) {
+		block_t blkaddr;
+
+		blkaddr = datablock_addr(dn.inode, dn.node_page,
+						dn.ofs_in_node + i);
+
+		if (!__is_valid_data_blkaddr(blkaddr))
+			break;
+
+		if (!f2fs_is_valid_blkaddr(sbi, blkaddr, DATA_GENERIC)) {
+			ret = -EFAULT;
+			goto out_put_dnode;
+		}
+		cc->nr_cpages++;
+	}
+
+	/* nothing to decompress */
+	if (cc->nr_cpages == 0) {
+		ret = 0;
+		goto out_put_dnode;
+	}
+
+	dic = f2fs_alloc_dic(cc);
+	if (IS_ERR(dic)) {
+		ret = PTR_ERR(dic);
+		goto out_put_dnode;
+	}
+
+	for (i = 0; i < dic->nr_cpages; i++) {
+		struct page *page = dic->cpages[i];
+		block_t blkaddr;
+
+		blkaddr = datablock_addr(dn.inode, dn.node_page,
+						dn.ofs_in_node + i + 1);
+
+		if (bio && !page_is_mergeable(sbi, bio,
+					*last_block_in_bio, blkaddr)) {
+submit_and_realloc:
+			__submit_bio(sbi, bio, DATA);
+			bio = NULL;
+		}
+
+		if (!bio) {
+			bio = f2fs_grab_read_bio(inode, blkaddr, nr_pages,
+					is_readahead ? REQ_RAHEAD : 0,
+					page->index);
+			if (IS_ERR(bio)) {
+				ret = PTR_ERR(bio);
+				bio = NULL;
+				dic->failed = true;
+				if (refcount_sub_and_test(dic->nr_cpages - i,
+							&dic->ref))
+					f2fs_decompress_end_io(dic->rpages,
+							cc->cluster_size, true,
+							false);
+				f2fs_free_dic(dic);
+				f2fs_put_dnode(&dn);
+				*bio_ret = bio;
+				return ret;
+			}
+		}
+
+		f2fs_wait_on_block_writeback(inode, blkaddr);
+
+		if (bio_add_page(bio, page, blocksize, 0) < blocksize)
+			goto submit_and_realloc;
+
+		inc_page_count(sbi, F2FS_RD_DATA);
+		ClearPageError(page);
+		*last_block_in_bio = blkaddr;
+	}
+
+	f2fs_put_dnode(&dn);
+
+	*bio_ret = bio;
+	return 0;
+
+out_put_dnode:
+	f2fs_put_dnode(&dn);
+out:
+	f2fs_decompress_end_io(cc->rpages, cc->cluster_size, true, false);
+	*bio_ret = bio;
+	return ret;
+}
+#endif
+
 /*
  * This function was originally taken from fs/mpage.c, and customized for f2fs.
  * Major change was from block_size == page_size in f2fs by default.
···
  * use ->readpage() or do the necessary surgery to decouple ->readpages()
  * from read-ahead.
  */
-static int f2fs_mpage_readpages(struct address_space *mapping,
+int f2fs_mpage_readpages(struct address_space *mapping,
 			struct list_head *pages, struct page *page,
 			unsigned nr_pages, bool is_readahead)
 {
···
 	sector_t last_block_in_bio = 0;
 	struct inode *inode = mapping->host;
 	struct f2fs_map_blocks map;
+#ifdef CONFIG_F2FS_FS_COMPRESSION
+	struct compress_ctx cc = {
+		.inode = inode,
+		.log_cluster_size = F2FS_I(inode)->i_log_cluster_size,
+		.cluster_size = F2FS_I(inode)->i_cluster_size,
+		.cluster_idx = NULL_CLUSTER,
+		.rpages = NULL,
+		.cpages = NULL,
+		.nr_rpages = 0,
+		.nr_cpages = 0,
+	};
+#endif
+	unsigned max_nr_pages = nr_pages;
 	int ret = 0;
 
 	map.m_pblk = 0;
···
 				goto next_page;
 		}
 
-		ret = f2fs_read_single_page(inode, page, nr_pages, &map, &bio,
-					&last_block_in_bio, is_readahead);
+#ifdef CONFIG_F2FS_FS_COMPRESSION
+		if (f2fs_compressed_file(inode)) {
+			/* there are remained comressed pages, submit them */
+			if (!f2fs_cluster_can_merge_page(&cc, page->index)) {
+				ret = f2fs_read_multi_pages(&cc, &bio,
+							max_nr_pages,
+							&last_block_in_bio,
+							is_readahead);
+				f2fs_destroy_compress_ctx(&cc);
+				if (ret)
+					goto set_error_page;
+			}
+			ret = f2fs_is_compressed_cluster(inode, page->index);
+			if (ret < 0)
+				goto set_error_page;
+			else if (!ret)
+				goto read_single_page;
+
+			ret = f2fs_init_compress_ctx(&cc);
+			if (ret)
+				goto set_error_page;
+
+			f2fs_compress_ctx_add_page(&cc, page);
+
+			goto next_page;
+		}
+read_single_page:
+#endif
+
+		ret = f2fs_read_single_page(inode, page, max_nr_pages, &map,
+					&bio, &last_block_in_bio, is_readahead);
 		if (ret) {
+#ifdef CONFIG_F2FS_FS_COMPRESSION
+set_error_page:
+#endif
 			SetPageError(page);
 			zero_user_segment(page, 0, PAGE_SIZE);
 			unlock_page(page);
···
 next_page:
 		if (pages)
 			put_page(page);
+
+#ifdef CONFIG_F2FS_FS_COMPRESSION
+		if (f2fs_compressed_file(inode)) {
+			/* last page */
+			if (nr_pages == 1 && !f2fs_cluster_is_empty(&cc)) {
+				ret = f2fs_read_multi_pages(&cc, &bio,
+							max_nr_pages,
+							&last_block_in_bio,
+							is_readahead);
+				f2fs_destroy_compress_ctx(&cc);
+			}
+		}
+#endif
 	}
 	BUG_ON(pages && !list_empty(pages));
 	if (bio)
···
 	int ret = -EAGAIN;
 
 	trace_f2fs_readpage(page, DATA);
+
+	if (!f2fs_is_compress_backend_ready(inode)) {
+		unlock_page(page);
+		return -EOPNOTSUPP;
+	}
 
 	/* If the file has inline data, try to read it directly */
 	if (f2fs_has_inline_data(inode))
···
 
 	trace_f2fs_readpages(inode, page, nr_pages);
 
+	if (!f2fs_is_compress_backend_ready(inode))
+		return 0;
+
 	/* If the file has inline data, skip readpages */
 	if (f2fs_has_inline_data(inode))
 		return 0;
···
 	return f2fs_mpage_readpages(mapping, pages, NULL, nr_pages, true);
 }
 
-static int encrypt_one_page(struct f2fs_io_info *fio)
+int f2fs_encrypt_one_page(struct f2fs_io_info *fio)
 {
 	struct inode *inode = fio->page->mapping->host;
-	struct page *mpage;
+	struct page *mpage, *page;
 	gfp_t gfp_flags = GFP_NOFS;
 
 	if (!f2fs_encrypted_file(inode))
 		return 0;
 
+	page = fio->compressed_page ? fio->compressed_page : fio->page;
+
 	/* wait for GCed page writeback via META_MAPPING */
 	f2fs_wait_on_block_writeback(inode, fio->old_blkaddr);
 
 retry_encrypt:
-	fio->encrypted_page = fscrypt_encrypt_pagecache_blocks(fio->page,
-							       PAGE_SIZE, 0,
-							       gfp_flags);
+	fio->encrypted_page = fscrypt_encrypt_pagecache_blocks(page,
+					PAGE_SIZE, 0, gfp_flags);
 	if (IS_ERR(fio->encrypted_page)) {
 		/* flush pending IOs and wait for a while in the ENOMEM case */
 		if (PTR_ERR(fio->encrypted_page) == -ENOMEM) {
···
 	if (ipu_force ||
 		(__is_valid_data_blkaddr(fio->old_blkaddr) &&
 					need_inplace_update(fio))) {
-		err = encrypt_one_page(fio);
+		err = f2fs_encrypt_one_page(fio);
 		if (err)
 			goto out_writepage;
 
···
 
 	fio->version = ni.version;
 
-	err = encrypt_one_page(fio);
+	err = f2fs_encrypt_one_page(fio);
 	if (err)
 		goto out_writepage;
 
 	set_page_writeback(page);
 	ClearPageError(page);
+
+	if (fio->compr_blocks && fio->old_blkaddr == COMPRESS_ADDR)
+		f2fs_i_compr_blocks_update(inode, fio->compr_blocks - 1, false);
 
 	/* LFS mode write path */
 	f2fs_outplace_write_data(&dn, fio);
···
 	return err;
 }
 
-static int __write_data_page(struct page *page, bool *submitted,
+int f2fs_write_single_data_page(struct page *page, int *submitted,
 				struct bio **bio,
 				sector_t *last_block,
 				struct writeback_control *wbc,
-				enum iostat_type io_type)
+				enum iostat_type io_type,
+				int compr_blocks)
 {
 	struct inode *inode = page->mapping->host;
 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
 	loff_t i_size = i_size_read(inode);
-	const pgoff_t end_index = ((unsigned long long) i_size)
+	const pgoff_t end_index = ((unsigned long long)i_size)
 							>> PAGE_SHIFT;
 	loff_t psize = (loff_t)(page->index + 1) << PAGE_SHIFT;
 	unsigned offset = 0;
···
 		.page = page,
 		.encrypted_page = NULL,
 		.submitted = false,
+		.compr_blocks = compr_blocks,
 		.need_lock = LOCK_RETRY,
 		.io_type = io_type,
 		.io_wbc = wbc,
···
 	if (unlikely(is_sbi_flag_set(sbi, SBI_POR_DOING)))
 		goto redirty_out;
 
-	if (page->index < end_index || f2fs_verity_in_progress(inode))
+	if (page->index < end_index ||
+			f2fs_verity_in_progress(inode) ||
+			compr_blocks)
 		goto write;
 
 	/*
···
 		f2fs_remove_dirty_inode(inode);
 		submitted = NULL;
 	}
-
 	unlock_page(page);
 	if (!S_ISDIR(inode->i_mode) && !IS_NOQUOTA(inode) &&
 					!F2FS_I(inode)->cp_task)
···
 	}
 
 	if (submitted)
-		*submitted = fio.submitted;
+		*submitted = fio.submitted ? 1 : 0;
 
 	return 0;
 
···
 static int f2fs_write_data_page(struct page *page,
 					struct writeback_control *wbc)
 {
-	return __write_data_page(page, NULL, NULL, NULL, wbc, FS_DATA_IO);
+#ifdef CONFIG_F2FS_FS_COMPRESSION
+	struct inode *inode = page->mapping->host;
+
+	if (unlikely(f2fs_cp_error(F2FS_I_SB(inode))))
+		goto out;
+
+	if (f2fs_compressed_file(inode)) {
+		if (f2fs_is_compressed_cluster(inode, page->index)) {
+			redirty_page_for_writepage(wbc, page);
+			return AOP_WRITEPAGE_ACTIVATE;
+		}
+	}
+out:
+#endif
+
+	return f2fs_write_single_data_page(page, NULL, NULL, NULL,
+						wbc, FS_DATA_IO, 0);
 }
 
 /*
···
 					enum iostat_type io_type)
 {
 	int ret = 0;
-	int done = 0;
+	int done = 0, retry = 0;
 	struct pagevec pvec;
 	struct f2fs_sb_info *sbi = F2FS_M_SB(mapping);
 	struct bio *bio = NULL;
 	sector_t last_block;
+#ifdef CONFIG_F2FS_FS_COMPRESSION
+	struct inode *inode = mapping->host;
+	struct compress_ctx cc = {
+		.inode = inode,
+		.log_cluster_size = F2FS_I(inode)->i_log_cluster_size,
+		.cluster_size = F2FS_I(inode)->i_cluster_size,
+		.cluster_idx = NULL_CLUSTER,
+		.rpages = NULL,
+		.nr_rpages = 0,
+		.cpages = NULL,
+		.rbuf = NULL,
+		.cbuf = NULL,
+		.rlen = PAGE_SIZE * F2FS_I(inode)->i_cluster_size,
+		.private = NULL,
+	};
+#endif
 	int nr_pages;
 	pgoff_t uninitialized_var(writeback_index);
 	pgoff_t index;
···
 	int range_whole = 0;
 	xa_mark_t tag;
 	int nwritten = 0;
+	int submitted = 0;
+	int i;
 
 	pagevec_init(&pvec);
 
···
 	else
 		tag = PAGECACHE_TAG_DIRTY;
 retry:
+	retry = 0;
 	if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages)
 		tag_pages_for_writeback(mapping, index, end);
 	done_index = index;
-	while (!done && (index <= end)) {
-		int i;
-
+	while (!done && !retry && (index <= end)) {
 		nr_pages = pagevec_lookup_range_tag(&pvec, mapping, &index, end,
 				tag);
 		if (nr_pages == 0)
···
 
 		for (i = 0; i < nr_pages; i++) {
 			struct page *page = pvec.pages[i];
-			bool submitted = false;
+			bool need_readd;
+readd:
+			need_readd = false;
+#ifdef CONFIG_F2FS_FS_COMPRESSION
+			if (f2fs_compressed_file(inode)) {
+				ret = f2fs_init_compress_ctx(&cc);
+				if (ret) {
+					done = 1;
+					break;
+				}
 
+				if (!f2fs_cluster_can_merge_page(&cc,
+								page->index)) {
+					ret = f2fs_write_multi_pages(&cc,
+						&submitted, wbc, io_type);
+					if (!ret)
+						need_readd = true;
+					goto result;
+				}
+
+				if (unlikely(f2fs_cp_error(sbi)))
+					goto lock_page;
+
+				if (f2fs_cluster_is_empty(&cc)) {
+					void *fsdata = NULL;
+					struct page *pagep;
+					int ret2;
+
+					ret2 = f2fs_prepare_compress_overwrite(
+							inode, &pagep,
+							page->index, &fsdata);
+					if (ret2 < 0) {
+						ret = ret2;
+						done = 1;
+						break;
+					} else if (ret2 &&
+						!f2fs_compress_write_end(inode,
+								fsdata, page->index,
+								1)) {
+						retry = 1;
+						break;
+					}
+				} else {
+					goto lock_page;
+				}
+			}
+#endif
 			/* give a priority to WB_SYNC threads */
 			if (atomic_read(&sbi->wb_sync_req[DATA]) &&
 					wbc->sync_mode == WB_SYNC_NONE) {
 				done = 1;
 				break;
 			}
-
+#ifdef CONFIG_F2FS_FS_COMPRESSION
+lock_page:
+#endif
 			done_index = page->index;
 retry_write:
 			lock_page(page);
···
 			if (!clear_page_dirty_for_io(page))
 				goto continue_unlock;
 
-			ret = __write_data_page(page, &submitted, &bio,
-					&last_block, wbc, io_type);
+#ifdef CONFIG_F2FS_FS_COMPRESSION
+			if (f2fs_compressed_file(inode)) {
+				get_page(page);
+				f2fs_compress_ctx_add_page(&cc, page);
+				continue;
+			}
+#endif
+			ret = f2fs_write_single_data_page(page, &submitted,
+					&bio, &last_block, wbc, io_type, 0);
+			if (ret == AOP_WRITEPAGE_ACTIVATE)
+				unlock_page(page);
+#ifdef CONFIG_F2FS_FS_COMPRESSION
+result:
+#endif
+			nwritten += submitted;
+			wbc->nr_to_write -= submitted;
+
 			if (unlikely(ret)) {
 				/*
 				 * keep nr_to_write, since vfs uses this to
 				 * get # of written pages.
 				 */
 				if (ret == AOP_WRITEPAGE_ACTIVATE) {
-					unlock_page(page);
 					ret = 0;
-					continue;
+					goto next;
 				} else if (ret == -EAGAIN) {
 					ret = 0;
 					if (wbc->sync_mode == WB_SYNC_ALL) {
 						cond_resched();
 						congestion_wait(BLK_RW_ASYNC,
-									HZ/50);
+								HZ/50);
 						goto retry_write;
 					}
-					continue;
+					goto next;
 				}
 				done_index = page->index + 1;
 				done = 1;
 				break;
-			} else if (submitted) {
-				nwritten++;
 			}
 
-			if (--wbc->nr_to_write <= 0 &&
+			if (wbc->nr_to_write <= 0 &&
 					wbc->sync_mode == WB_SYNC_NONE) {
 				done = 1;
 				break;
 			}
+next:
+			if (need_readd)
+				goto readd;
 		}
 		pagevec_release(&pvec);
 		cond_resched();
 	}
-
-	if (!cycled && !done) {
+#ifdef CONFIG_F2FS_FS_COMPRESSION
+	/* flush remained pages in compress cluster */
+	if (f2fs_compressed_file(inode) && !f2fs_cluster_is_empty(&cc)) {
+		ret = f2fs_write_multi_pages(&cc, &submitted, wbc, io_type);
+		nwritten += submitted;
+		wbc->nr_to_write -= submitted;
+		if (ret) {
+			done = 1;
+			retry = 0;
+		}
+	}
+#endif
+	if ((!cycled && !done) || retry) {
 		cycled = 1;
 		index = 0;
 		end = writeback_index - 1;
···
 {
 	if (!S_ISREG(inode->i_mode))
 		return false;
+	if (f2fs_compressed_file(inode))
+		return true;
 	if (IS_NOQUOTA(inode))
 		return false;
 	/* to avoid deadlock in path of data flush */
···
 		__do_map_lock(sbi, flag, true);
 		locked = true;
 	}
+
 restart:
 	/* check inline_data */
 	ipage = f2fs_get_node_page(sbi, inode->i_ino);
···
 		if (err)
 			goto fail;
 	}
+
+#ifdef CONFIG_F2FS_FS_COMPRESSION
+	if (f2fs_compressed_file(inode)) {
+		int ret;
+
+		*fsdata = NULL;
+
+		ret = f2fs_prepare_compress_overwrite(inode, pagep,
+							index, fsdata);
+		if (ret < 0) {
+			err = ret;
+			goto fail;
+		} else if (ret) {
+			return 0;
+		}
+	}
+#endif
+
 repeat:
 	/*
 	 * Do not use grab_cache_page_write_begin() to avoid deadlock due to
···
 		err = -ENOMEM;
 		goto fail;
 	}
+
+	/* TODO: cluster can be compressed due to race with .writepage */
 
 	*pagep = page;
 
···
 		else
 			SetPageUptodate(page);
 	}
+
+#ifdef CONFIG_F2FS_FS_COMPRESSION
+	/* overwrite compressed file */
+	if (f2fs_compressed_file(inode) && fsdata) {
+		f2fs_compress_write_end(inode, fsdata, page->index, copied);
+		f2fs_update_time(F2FS_I_SB(inode), REQ_TIME);
+		return copied;
+	}
+#endif
+
 	if (!copied)
 		goto unlock_out;
 
···
 	if (ret)
 		return ret;
 
+	if (f2fs_disable_compressed_file(inode))
+		return -EINVAL;
+
 	ret = check_swap_activate(file, sis->max);
 	if (ret)
 		return ret;
···
 {
 	mempool_destroy(bio_post_read_ctx_pool);
 	kmem_cache_destroy(bio_post_read_ctx_cache);
+}
+
+int f2fs_init_post_read_wq(struct f2fs_sb_info *sbi)
+{
+	if (!f2fs_sb_has_encrypt(sbi) &&
+		!f2fs_sb_has_verity(sbi) &&
+		!f2fs_sb_has_compression(sbi))
+		return 0;
+
+	sbi->post_read_wq = alloc_workqueue("f2fs_post_read_wq",
+						 WQ_UNBOUND | WQ_HIGHPRI,
+						 num_online_cpus());
+	if (!sbi->post_read_wq)
+		return -ENOMEM;
+	return 0;
+}
+
+void f2fs_destroy_post_read_wq(struct f2fs_sb_info *sbi)
+{
+	if (sbi->post_read_wq)
+		destroy_workqueue(sbi->post_read_wq);
 }
 
 int __init f2fs_init_bio_entry_cache(void)

fs/f2fs/debug.c

···
 	si->inline_xattr = atomic_read(&sbi->inline_xattr);
 	si->inline_inode = atomic_read(&sbi->inline_inode);
 	si->inline_dir = atomic_read(&sbi->inline_dir);
+	si->compr_inode = atomic_read(&sbi->compr_inode);
+	si->compr_blocks = atomic_read(&sbi->compr_blocks);
 	si->append = sbi->im[APPEND_INO].ino_num;
 	si->update = sbi->im[UPDATE_INO].ino_num;
 	si->orphans = sbi->im[ORPHAN_INO].ino_num;
···
 			   si->inline_inode);
 		seq_printf(s, "  - Inline_dentry Inode: %u\n",
 			   si->inline_dir);
+		seq_printf(s, "  - Compressed Inode: %u, Blocks: %u\n",
+			   si->compr_inode, si->compr_blocks);
 		seq_printf(s, "  - Orphan/Append/Update Inode: %u, %u, %u\n",
 			   si->orphans, si->append, si->update);
 		seq_printf(s, "\nMain area: %d segs, %d secs %d zones\n",
···
 	atomic_set(&sbi->inline_xattr, 0);
 	atomic_set(&sbi->inline_inode, 0);
 	atomic_set(&sbi->inline_dir, 0);
+	atomic_set(&sbi->compr_inode, 0);
+	atomic_set(&sbi->compr_blocks, 0);
 	atomic_set(&sbi->inplace_count, 0);
 	for (i = META_CP; i < META_MAX; i++)
 		atomic_set(&sbi->meta_count[i], 0);

fs/f2fs/f2fs.h

···
 			 */
 typedef u32 nid_t;
 
+#define COMPRESS_EXT_NUM		16
+
 struct f2fs_mount_info {
 	unsigned int opt;
 	int write_io_size_bits;		/* Write IO size bits */
···
 	block_t unusable_cap;		/* Amount of space allowed to be
 					 * unusable when disabling checkpoint
 					 */
+
+	/* For compression */
+	unsigned char compress_algorithm;	/* algorithm type */
+	unsigned compress_log_size;		/* cluster log size */
+	unsigned char compress_ext_cnt;		/* extension count */
+	unsigned char extensions[COMPRESS_EXT_NUM][F2FS_EXTENSION_LEN];	/* extensions */
 };
 
 #define F2FS_FEATURE_ENCRYPT		0x0001
···
 #define F2FS_FEATURE_VERITY		0x0400
 #define F2FS_FEATURE_SB_CHKSUM		0x0800
 #define F2FS_FEATURE_CASEFOLD		0x1000
+#define F2FS_FEATURE_COMPRESSION	0x2000
 
 #define __F2FS_HAS_FEATURE(raw_super, mask)				\
 	((raw_super->feature & cpu_to_le32(mask)) != 0)
···
 	int i_inline_xattr_size;	/* inline xattr size */
 	struct timespec64 i_crtime;	/* inode creation time */
 	struct timespec64 i_disk_time[4];/* inode disk times */
+
+	/* for file compress */
+	u64 i_compr_blocks;			/* # of compressed blocks */
+	unsigned char i_compress_algorithm;	/* algorithm type */
+	unsigned char i_log_cluster_size;	/* log of cluster size */
+	unsigned int i_cluster_size;		/* cluster size */
 };
 
 static inline void get_extent_info(struct extent_info *ext,
···
 enum cp_reason_type {
 	CP_NO_NEEDED,
 	CP_NON_REGULAR,
+	CP_COMPRESSED,
 	CP_HARDLINK,
 	CP_SB_NEED_CP,
 	CP_WRONG_PINO,
···
 	block_t old_blkaddr;	/* old block address before Cow */
 	struct page *page;	/* page to be written */
 	struct page *encrypted_page;	/* encrypted page */
+	struct page *compressed_page;	/* compressed page */
 	struct list_head list;		/* serialize IOs */
 	bool submitted;		/* indicate IO submission */
 	int need_lock;		/* indicate we need to lock cp_rwsem */
 	bool in_list;		/* indicate fio is in io_list */
 	bool is_por;		/* indicate IO is from recovery or not */
 	bool retry;		/* need to reallocate block address */
+	int compr_blocks;	/* # of compressed block addresses */
+	bool encrypted;		/* indicate file is encrypted */
 	enum iostat_type io_type;	/* io type */
 	struct writeback_control *io_wbc; /* writeback control */
 	struct bio **bio;		/* bio for ipu */
···
 	FSYNC_MODE_NOBARRIER,	/* fsync behaves nobarrier based on posix */
 };
 
+/*
+ * this value is set in page as a private data which indicate that
+ * the page is atomically written, and it is in inmem_pages list.
+ */
+#define ATOMIC_WRITTEN_PAGE		((unsigned long)-1)
+#define DUMMY_WRITTEN_PAGE		((unsigned long)-2)
+
+#define IS_ATOMIC_WRITTEN_PAGE(page)			\
+		(page_private(page) == (unsigned long)ATOMIC_WRITTEN_PAGE)
+#define IS_DUMMY_WRITTEN_PAGE(page)			\
+		(page_private(page) == (unsigned long)DUMMY_WRITTEN_PAGE)
+
 #ifdef CONFIG_FS_ENCRYPTION
 #define DUMMY_ENCRYPTION_ENABLED(sbi) \
 			(unlikely(F2FS_OPTION(sbi).test_dummy_encryption))
 #else
 #define DUMMY_ENCRYPTION_ENABLED(sbi) (0)
 #endif
+
+/* For compression */
+enum compress_algorithm_type {
+	COMPRESS_LZO,
+	COMPRESS_LZ4,
+	COMPRESS_MAX,
+};
+
+#define COMPRESS_DATA_RESERVED_SIZE		4
+struct compress_data {
+	__le32 clen;			/* compressed data size */
+	__le32 chksum;			/* checksum of compressed data */
+	__le32 reserved[COMPRESS_DATA_RESERVED_SIZE];	/* reserved */
+	u8 cdata[];			/* compressed data */
+};
+
+#define COMPRESS_HEADER_SIZE	(sizeof(struct compress_data))
+
+#define F2FS_COMPRESSED_PAGE_MAGIC	0xF5F2C000
+
+/* compress context */
+struct compress_ctx {
+	struct inode *inode;		/* inode the context belong to */
+	pgoff_t cluster_idx;		/* cluster index number */
+	unsigned int cluster_size;	/* page count in cluster */
+	unsigned int log_cluster_size;	/* log of cluster size */
+	struct page **rpages;		/* pages store raw data in cluster */
+	unsigned int nr_rpages;		/* total page number in rpages */
+	struct page **cpages;		/* pages store compressed data in cluster */
+	unsigned int nr_cpages;		/* total page number in cpages */
+	void *rbuf;			/* virtual mapped address on rpages */
+	struct compress_data *cbuf;	/* virtual mapped address on cpages */
+	size_t rlen;			/* valid data length in rbuf */
+	size_t clen;			/* valid data length in cbuf */
+	void *private;			/* payload buffer for specified compression algorithm */
+};
+
+/* compress context for write IO path */
+struct compress_io_ctx {
+	u32 magic;			/* magic number to indicate page is compressed */
+	struct inode *inode;		/* inode the context belong to */
+	struct page **rpages;		/* pages store raw data in cluster */
+	unsigned int nr_rpages;		/* total page number in rpages */
+	refcount_t ref;			/* referrence count of raw page */
+};
+
+/* decompress io context for read IO path */
+struct decompress_io_ctx {
+	u32 magic;			/* magic number to indicate page is compressed */
+	struct inode *inode;		/* inode the context belong to */
+	pgoff_t cluster_idx;		/* cluster index number */
+	unsigned int cluster_size;	/* page count in cluster */
+	unsigned int log_cluster_size;	/* log of cluster size */
+	struct page **rpages;		/* pages store raw data in cluster */
+	unsigned int nr_rpages;		/* total page number in rpages */
+	struct page **cpages;		/* pages store compressed data in cluster */
+	unsigned int nr_cpages;		/* total page number in cpages */
+	struct page **tpages;		/* temp pages to pad holes in cluster */
+	void *rbuf;			/* virtual mapped address on rpages */
+	struct compress_data *cbuf;	/* virtual mapped address on cpages */
+	size_t rlen;			/* valid data length in rbuf */
+	size_t clen;			/* valid data length in cbuf */
+	refcount_t ref;			/* referrence count of compressed page */
+	bool failed;			/* indicate IO error during decompression */
+};
+
+#define NULL_CLUSTER			((unsigned int)(~0))
+#define MIN_COMPRESS_LOG_SIZE		2
+#define MAX_COMPRESS_LOG_SIZE		8
 
 struct f2fs_sb_info {
 	struct super_block *sb;			/* pointer to VFS super block */
···
 	atomic_t inline_xattr;			/* # of inline_xattr inodes */
 	atomic_t inline_inode;			/* # of inline_data inodes */
 	atomic_t inline_dir;			/* # of inline_dentry inodes */
+	atomic_t compr_inode;			/* # of compressed inodes */
+	atomic_t compr_blocks;			/* # of compressed blocks */
 	atomic_t vw_cnt;			/* # of volatile writes */
 	atomic_t max_aw_cnt;			/* max # of atomic writes */
 	atomic_t max_vw_cnt;			/* max # of volatile writes */
···
 
 	/* Precomputed FS UUID checksum for seeding other checksums */
 	__u32 s_chksum_seed;
+
+	struct workqueue_struct *post_read_wq;	/* post read workqueue */
 };
 
 struct f2fs_private_dio {
···
 /*
  * On-disk inode flags (f2fs_inode::i_flags)
  */
+#define F2FS_COMPR_FL			0x00000004 /* Compress file */
 #define F2FS_SYNC_FL			0x00000008 /* Synchronous updates */
 #define F2FS_IMMUTABLE_FL		0x00000010 /* Immutable file */
 #define F2FS_APPEND_FL			0x00000020 /* writes to file may only append */
 #define F2FS_NODUMP_FL			0x00000040 /* do not dump file */
 #define F2FS_NOATIME_FL			0x00000080 /* do not update atime */
+#define F2FS_NOCOMP_FL			0x00000400 /* Don't compress */
 #define F2FS_INDEX_FL			0x00001000 /* hash-indexed directory */
 #define F2FS_DIRSYNC_FL			0x00010000 /* dirsync behaviour (directories only) */
 #define F2FS_PROJINHERIT_FL		0x20000000 /* Create with parents projid */
···
 /* Flags that should be inherited by new inodes from their parent. */
 #define F2FS_FL_INHERITED (F2FS_SYNC_FL | F2FS_NODUMP_FL | F2FS_NOATIME_FL | \
 			   F2FS_DIRSYNC_FL | F2FS_PROJINHERIT_FL | \
-			   F2FS_CASEFOLD_FL)
+			   F2FS_CASEFOLD_FL | F2FS_COMPR_FL | F2FS_NOCOMP_FL)
 
 /* Flags that are appropriate for regular files (all but dir-specific ones). */
 #define F2FS_REG_FLMASK		(~(F2FS_DIRSYNC_FL | F2FS_PROJINHERIT_FL | \
···
 	FI_PIN_FILE,		/* indicate file should not be gced */
 	FI_ATOMIC_REVOKE_REQUEST, /* request to drop atomic data */
 	FI_VERITY_IN_PROGRESS,	/* building fs-verity Merkle tree */
+	FI_COMPRESSED_FILE,	/* indicate file's data can be compressed */
+	FI_MMAP_FILE,		/* indicate file was mmapped */
 };
 
 static inline void __mark_inode_dirty_flag(struct inode *inode,
···
 	case FI_DATA_EXIST:
 	case FI_INLINE_DOTS:
 	case FI_PIN_FILE:
+	case FI_COMPRESSED_FILE:
 		f2fs_mark_inode_dirty_sync(inode, true);
 	}
 }
···
 	return is_inode_flag_set(inode, FI_INLINE_XATTR);
 }
 
+static inline int f2fs_compressed_file(struct inode *inode)
+{
+	return S_ISREG(inode->i_mode) &&
+		is_inode_flag_set(inode, FI_COMPRESSED_FILE);
+}
+
 static inline unsigned int addrs_per_inode(struct inode *inode)
 {
 	unsigned int addrs = CUR_ADDRS_PER_INODE(inode) -
 				get_inline_xattr_addrs(inode);
-	return ALIGN_DOWN(addrs, 1);
+
+	if (!f2fs_compressed_file(inode))
+		return addrs;
+	return ALIGN_DOWN(addrs, F2FS_I(inode)->i_cluster_size);
 }
 
 static inline unsigned int addrs_per_block(struct inode *inode)
 {
-	return ALIGN_DOWN(DEF_ADDRS_PER_BLOCK, 1);
+	if (!f2fs_compressed_file(inode))
+		return DEF_ADDRS_PER_BLOCK;
+	return ALIGN_DOWN(DEF_ADDRS_PER_BLOCK, F2FS_I(inode)->i_cluster_size);
 }
 
 static inline void *inline_xattr_addr(struct inode *inode, struct page *page)
···
 static inline int f2fs_has_inline_dots(struct inode *inode)
 {
 	return is_inode_flag_set(inode, FI_INLINE_DOTS);
+}
+
+static inline int f2fs_is_mmap_file(struct inode *inode)
+{
+	return is_inode_flag_set(inode, FI_MMAP_FILE);
 }
 
 static inline bool f2fs_is_pinned_file(struct inode *inode)
···
 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
 
 	if (!test_opt(sbi, EXTENT_CACHE) ||
-			is_inode_flag_set(inode, FI_NO_EXTENT))
+			is_inode_flag_set(inode, FI_NO_EXTENT) ||
+			is_inode_flag_set(inode, FI_COMPRESSED_FILE))
 		return false;
 
 	/*
···
 
 static inline bool __is_valid_data_blkaddr(block_t blkaddr)
 {
-	if (blkaddr == NEW_ADDR || blkaddr == NULL_ADDR)
+	if (blkaddr == NEW_ADDR || blkaddr == NULL_ADDR ||
+			blkaddr == COMPRESS_ADDR)
 		return false;
 	return true;
 }
···
 int __init f2fs_init_bioset(void);
 void f2fs_destroy_bioset(void);
 struct bio *f2fs_bio_alloc(struct f2fs_sb_info *sbi, int npages, bool no_fail);
-int f2fs_init_post_read_processing(void);
-void f2fs_destroy_post_read_processing(void);
 int f2fs_init_bio_entry_cache(void);
 void f2fs_destroy_bio_entry_cache(void);
+void f2fs_submit_bio(struct f2fs_sb_info *sbi,
+				struct bio *bio, enum page_type type);
 void f2fs_submit_merged_write(struct f2fs_sb_info *sbi, enum page_type type);
 void f2fs_submit_merged_write_cond(struct f2fs_sb_info *sbi,
 				struct inode *inode, struct page *page,
···
 int f2fs_get_block(struct dnode_of_data *dn, pgoff_t index);
 int f2fs_preallocate_blocks(struct kiocb *iocb, struct iov_iter *from);
 int f2fs_reserve_block(struct dnode_of_data *dn, pgoff_t index);
+int f2fs_mpage_readpages(struct address_space *mapping,
+			struct list_head *pages, struct page *page,
+			unsigned nr_pages, bool is_readahead);
 struct page *f2fs_get_read_data_page(struct inode *inode, pgoff_t index,
 			int op_flags, bool for_write);
 struct page *f2fs_find_data_page(struct inode *inode, pgoff_t index);
···
 			int create, int flag);
 int f2fs_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
 			u64 start, u64 len);
+int f2fs_encrypt_one_page(struct f2fs_io_info *fio);
 bool f2fs_should_update_inplace(struct inode *inode, struct f2fs_io_info *fio);
 bool f2fs_should_update_outplace(struct inode *inode, struct f2fs_io_info *fio);
+int f2fs_write_single_data_page(struct page *page, int *submitted,
+				struct bio **bio, sector_t *last_block,
+				struct writeback_control *wbc,
+				enum iostat_type io_type,
+				int compr_blocks);
 void f2fs_invalidate_page(struct page *page, unsigned int offset,
 			unsigned int length);
 int f2fs_release_page(struct page *page, gfp_t wait);
···
 #endif
 bool f2fs_overwrite_io(struct inode *inode, loff_t pos, size_t len);
 void f2fs_clear_page_cache_dirty_tag(struct page *page);
+int f2fs_init_post_read_processing(void);
+void f2fs_destroy_post_read_processing(void);
+int f2fs_init_post_read_wq(struct f2fs_sb_info *sbi);
+void f2fs_destroy_post_read_wq(struct f2fs_sb_info *sbi);
 
 /*
  * gc.c
···
 	int nr_discard_cmd;
 	unsigned int undiscard_blks;
 	int inline_xattr, inline_inode, inline_dir, append, update, orphans;
+	int compr_inode, compr_blocks;
 	int aw_cnt, max_aw_cnt, vw_cnt, max_vw_cnt;
 	unsigned int valid_count, valid_node_count, valid_inode_count, discard_blks;
 	unsigned int bimodal, avg_vblocks;
···
 		if (f2fs_has_inline_dentry(inode))			\
 			(atomic_dec(&F2FS_I_SB(inode)->inline_dir));	\
 	} while (0)
+#define stat_inc_compr_inode(inode)					\
+	do {								\
+		if (f2fs_compressed_file(inode))			\
+			(atomic_inc(&F2FS_I_SB(inode)->compr_inode));	\
+	} while (0)
+#define stat_dec_compr_inode(inode)					\
+	do {								\
+		if (f2fs_compressed_file(inode))			\
+			(atomic_dec(&F2FS_I_SB(inode)->compr_inode));	\
+	} while (0)
+#define stat_add_compr_blocks(inode, blocks)				\
+		(atomic_add(blocks, &F2FS_I_SB(inode)->compr_blocks))
+#define stat_sub_compr_blocks(inode, blocks)				\
+		(atomic_sub(blocks, &F2FS_I_SB(inode)->compr_blocks))
 #define stat_inc_meta_count(sbi, blkaddr)				\
 	do {								\
 		if (blkaddr < SIT_I(sbi)->sit_base_addr)		\
···
 #define stat_dec_inline_inode(inode)			do { } while (0)
 #define stat_inc_inline_dir(inode)			do { } while (0)
 #define stat_dec_inline_dir(inode)			do { } while (0)
+#define stat_inc_compr_inode(inode)			do { } while (0)
+#define stat_dec_compr_inode(inode)			do { } while (0)
+#define stat_add_compr_blocks(inode, blocks)		do { } while (0)
+#define stat_sub_compr_blocks(inode, blocks)		do { } while (0)
 #define stat_inc_atomic_write(inode)			do { } while (0)
 #define stat_dec_atomic_write(inode)			do { } while (0)
 #define stat_update_max_atomic_write(inode)		do { } while (0)
···
  */
 static inline bool f2fs_post_read_required(struct inode *inode)
 {
-	return f2fs_encrypted_file(inode) || fsverity_active(inode);
+	return f2fs_encrypted_file(inode) || fsverity_active(inode) ||
+		f2fs_compressed_file(inode);
+}
+
+/*
+ * compress.c
+ */
+#ifdef CONFIG_F2FS_FS_COMPRESSION
+bool f2fs_is_compressed_page(struct page *page);
+struct page *f2fs_compress_control_page(struct page *page);
+int f2fs_prepare_compress_overwrite(struct inode *inode,
+			struct page **pagep, pgoff_t index, void **fsdata);
+bool f2fs_compress_write_end(struct inode *inode, void *fsdata,
+					pgoff_t index, unsigned copied);
+void f2fs_compress_write_end_io(struct bio *bio, struct page *page);
+bool f2fs_is_compress_backend_ready(struct inode *inode);
+void f2fs_decompress_pages(struct bio *bio, struct page *page, bool verity);
+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);
+int f2fs_write_multi_pages(struct compress_ctx *cc,
+						int *submitted,
+						struct writeback_control *wbc,
+						enum iostat_type io_type);
+int f2fs_is_compressed_cluster(struct inode *inode, pgoff_t index);
+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);
+struct decompress_io_ctx *f2fs_alloc_dic(struct compress_ctx *cc);
+void f2fs_free_dic(struct decompress_io_ctx *dic);
+void f2fs_decompress_end_io(struct page **rpages,
+			unsigned int cluster_size, bool err, bool verity);
+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);
+#else
+static inline bool f2fs_is_compressed_page(struct page *page) { return false; }
+static inline bool f2fs_is_compress_backend_ready(struct inode *inode)
+{
+	if (!f2fs_compressed_file(inode))
+		return true;
+	/* not support compression */
+	return false;
+}
+static inline struct page *f2fs_compress_control_page(struct page *page)
+{
+	WARN_ON_ONCE(1);
+	return ERR_PTR(-EINVAL);
+}
+#endif
+
+static inline void set_compress_context(struct inode *inode)
+{
+	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
+
+	F2FS_I(inode)->i_compress_algorithm =
+			F2FS_OPTION(sbi).compress_algorithm;
+	F2FS_I(inode)->i_log_cluster_size =
+			F2FS_OPTION(sbi).compress_log_size;
+	F2FS_I(inode)->i_cluster_size =
+			1 << F2FS_I(inode)->i_log_cluster_size;
+	F2FS_I(inode)->i_flags |= F2FS_COMPR_FL;
+	set_inode_flag(inode, FI_COMPRESSED_FILE);
+	stat_inc_compr_inode(inode);
+}
+
+static inline u64 f2fs_disable_compressed_file(struct inode *inode)
+{
+	struct f2fs_inode_info *fi = F2FS_I(inode);
+
+	if (!f2fs_compressed_file(inode))
+		return 0;
+	if (fi->i_compr_blocks)
+		return fi->i_compr_blocks;
+
+	fi->i_flags &= ~F2FS_COMPR_FL;
+	clear_inode_flag(inode, FI_COMPRESSED_FILE);
+	stat_dec_compr_inode(inode);
+	return 0;
 }
 
 #define F2FS_FEATURE_FUNCS(name, flagname) \
···
 F2FS_FEATURE_FUNCS(verity, VERITY);
 F2FS_FEATURE_FUNCS(sb_chksum, SB_CHKSUM);
 F2FS_FEATURE_FUNCS(casefold, CASEFOLD);
+F2FS_FEATURE_FUNCS(compression, COMPRESSION);
 
 #ifdef CONFIG_BLK_DEV_ZONED
 static inline bool f2fs_blkz_is_seq(struct f2fs_sb_info *sbi, int devi,
···
 #endif
 }
 
+static inline bool f2fs_may_compress(struct inode *inode)
+{
+	if (IS_SWAPFILE(inode) || f2fs_is_pinned_file(inode) ||
+				f2fs_is_atomic_file(inode) ||
+				f2fs_is_volatile_file(inode))
+		return false;
+	return S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode);
+}
+
+static inline void f2fs_i_compr_blocks_update(struct inode *inode,
+						u64 blocks, bool add)
+{
+	int diff = F2FS_I(inode)->i_cluster_size - blocks;
+
+	if (add) {
+		F2FS_I(inode)->i_compr_blocks += diff;
+		stat_add_compr_blocks(inode, diff);
+	} else {
+		F2FS_I(inode)->i_compr_blocks -= diff;
+		stat_sub_compr_blocks(inode, diff);
+	}
+	f2fs_mark_inode_dirty_sync(inode, true);
+}
+
 static inline int block_unaligned_IO(struct inode *inode,
 				struct kiocb *iocb, struct iov_iter *iter)
 {
···
 	if (f2fs_post_read_required(inode))
 		return true;
 	if (f2fs_is_multi_device(sbi))
+		return true;
+	if (f2fs_compressed_file(inode))
 		return true;
 	/*
 	 * for blkzoned device, fallback direct IO to buffered IO, so

fs/f2fs/file.c

···
 	struct inode *inode = file_inode(vmf->vma->vm_file);
 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
 	struct dnode_of_data dn;
-	int err;
+	bool need_alloc = true;
+	int err = 0;
 
 	if (unlikely(f2fs_cp_error(sbi))) {
 		err = -EIO;
···
 		goto err;
 	}
 
+#ifdef CONFIG_F2FS_FS_COMPRESSION
+	if (f2fs_compressed_file(inode)) {
+		int ret = f2fs_is_compressed_cluster(inode, page->index);
+
+		if (ret < 0) {
+			err = ret;
+			goto err;
+		} else if (ret) {
+			if (ret < F2FS_I(inode)->i_cluster_size) {
+				err = -EAGAIN;
+				goto err;
+			}
+			need_alloc = false;
+		}
+	}
+#endif
 	/* should do out of any locked page */
-	f2fs_balance_fs(sbi, true);
+	if (need_alloc)
+		f2fs_balance_fs(sbi, true);
 
 	sb_start_pagefault(inode->i_sb);
 
···
 		goto out_sem;
 	}
 
-	/* block allocation */
-	__do_map_lock(sbi, F2FS_GET_BLOCK_PRE_AIO, true);
-	set_new_dnode(&dn, inode, NULL, NULL, 0);
-	err = f2fs_get_block(&dn, page->index);
-	f2fs_put_dnode(&dn);
-	__do_map_lock(sbi, F2FS_GET_BLOCK_PRE_AIO, false);
-	if (err) {
-		unlock_page(page);
-		goto out_sem;
+	if (need_alloc) {
+		/* block allocation */
+		__do_map_lock(sbi, F2FS_GET_BLOCK_PRE_AIO, true);
+		set_new_dnode(&dn, inode, NULL, NULL, 0);
+		err = f2fs_get_block(&dn, page->index);
+		f2fs_put_dnode(&dn);
+		__do_map_lock(sbi, F2FS_GET_BLOCK_PRE_AIO, false);
+		if (err) {
+			unlock_page(page);
+			goto out_sem;
+		}
 	}
 
 	/* fill the page */
···
 
 	if (!S_ISREG(inode->i_mode))
 		cp_reason = CP_NON_REGULAR;
+	else if (f2fs_compressed_file(inode))
+		cp_reason = CP_COMPRESSED;
 	else if (inode->i_nlink != 1)
 		cp_reason = CP_HARDLINK;
 	else if (is_sbi_flag_set(sbi, SBI_NEED_CP))
···
 	if (unlikely(f2fs_cp_error(F2FS_I_SB(inode))))
 		return -EIO;
 
+	if (!f2fs_is_compress_backend_ready(inode))
+		return -EOPNOTSUPP;
+
 	/* we don't need to use inline_data strictly */
 	err = f2fs_convert_inline_inode(inode);
 	if (err)
···
 
 	file_accessed(file);
 	vma->vm_ops = &f2fs_file_vm_ops;
+	set_inode_flag(inode, FI_MMAP_FILE);
 	return 0;
 }
 
···
 
 	if (err)
 		return err;
+
+	if (!f2fs_is_compress_backend_ready(inode))
+		return -EOPNOTSUPP;
 
 	err = fsverity_file_open(inode, filp);
 	if (err)
···
 	int nr_free = 0, ofs = dn->ofs_in_node, len = count;
 	__le32 *addr;
 	int base = 0;
+	bool compressed_cluster = false;
+	int cluster_index = 0, valid_blocks = 0;
+	int cluster_size = F2FS_I(dn->inode)->i_cluster_size;
 
 	if (IS_INODE(dn->node_page) && f2fs_has_extra_attr(dn->inode))
 		base = get_extra_isize(dn->inode);
···
 	raw_node = F2FS_NODE(dn->node_page);
 	addr = blkaddr_in_node(raw_node) + base + ofs;
 
-	for (; count > 0; count--, addr++, dn->ofs_in_node++) {
+	/* Assumption: truncateion starts with cluster */
+	for (; count > 0; count--, addr++, dn->ofs_in_node++, cluster_index++) {
 		block_t blkaddr = le32_to_cpu(*addr);
+
+		if (f2fs_compressed_file(dn->inode) &&
+					!(cluster_index & (cluster_size - 1))) {
+			if (compressed_cluster)
+				f2fs_i_compr_blocks_update(dn->inode,
+							valid_blocks, false);
+			compressed_cluster = (blkaddr == COMPRESS_ADDR);
+			valid_blocks = 0;
+		}
 
 		if (blkaddr == NULL_ADDR)
 			continue;
···
 		dn->data_blkaddr = NULL_ADDR;
 		f2fs_set_data_blkaddr(dn);
 
-		if (__is_valid_data_blkaddr(blkaddr) &&
-			!f2fs_is_valid_blkaddr(sbi, blkaddr,
+		if (__is_valid_data_blkaddr(blkaddr)) {
+			if (!f2fs_is_valid_blkaddr(sbi, blkaddr,
 					DATA_GENERIC_ENHANCE))
-			continue;
+				continue;
+			if (compressed_cluster)
+				valid_blocks++;
+		}
 
-		f2fs_invalidate_blocks(sbi, blkaddr);
 		if (dn->ofs_in_node == 0 && IS_INODE(dn->node_page))
 			clear_inode_flag(dn->inode, FI_FIRST_BLOCK_WRITTEN);
+
+		f2fs_invalidate_blocks(sbi, blkaddr);
 		nr_free++;
 	}
+
+	if (compressed_cluster)
+		f2fs_i_compr_blocks_update(dn->inode, valid_blocks, false);
 
 	if (nr_free) {
 		pgoff_t fofs;
···
 		return 0;
 	}
 
+	if (f2fs_compressed_file(inode))
+		return 0;
+
 	page = f2fs_get_lock_data_page(inode, index, true);
 	if (IS_ERR(page))
 		return PTR_ERR(page) == -ENOENT ? 0 : PTR_ERR(page);
···
 	return 0;
 }
 
-int f2fs_truncate_blocks(struct inode *inode, u64 from, bool lock)
+static int do_truncate_blocks(struct inode *inode, u64 from, bool lock)
 {
 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
 	struct dnode_of_data dn;
···
 
 	trace_f2fs_truncate_blocks_exit(inode, err);
 	return err;
+}
+
+int f2fs_truncate_blocks(struct inode *inode, u64 from, bool lock)
+{
+	u64 free_from = from;
+
+	/*
+	 * for compressed file, only support cluster size
+	 * aligned truncation.
+	 */
+	if (f2fs_compressed_file(inode)) {
+		size_t cluster_shift = PAGE_SHIFT +
+					F2FS_I(inode)->i_log_cluster_size;
+		size_t cluster_mask = (1 << cluster_shift) - 1;
+
+		free_from = from >> cluster_shift;
+		if (from & cluster_mask)
+			free_from++;
+		free_from <<= cluster_shift;
+	}
+
+	return do_truncate_blocks(inode, free_from, lock);
 }
 
 int f2fs_truncate(struct inode *inode)
···
 
 	if (unlikely(f2fs_cp_error(F2FS_I_SB(inode))))
 		return -EIO;
+
+	if ((attr->ia_valid & ATTR_SIZE) &&
+		!f2fs_is_compress_backend_ready(inode))
+		return -EOPNOTSUPP;
 
 	err = setattr_prepare(dentry, attr);
 	if (err)
···
 	} else if (ret == -ENOENT) {
 		if (dn.max_level == 0)
 			return -ENOENT;
-		done = min((pgoff_t)ADDRS_PER_BLOCK(inode) - dn.ofs_in_node,
-									len);
+		done = min((pgoff_t)ADDRS_PER_BLOCK(inode) -
+						dn.ofs_in_node, len);
 		blkaddr += done;
 		do_replace += done;
 		goto next;
···
 		return -EIO;
 	if (!f2fs_is_checkpoint_ready(F2FS_I_SB(inode)))
 		return -ENOSPC;
+	if (!f2fs_is_compress_backend_ready(inode))
+		return -EOPNOTSUPP;
 
 	/* f2fs only support ->fallocate for regular file */
 	if (!S_ISREG(inode->i_mode))
···
 
 	if (IS_ENCRYPTED(inode) &&
 		(mode & (FALLOC_FL_COLLAPSE_RANGE | FALLOC_FL_INSERT_RANGE)))
+		return -EOPNOTSUPP;
+
+	if (f2fs_compressed_file(inode) &&
+		(mode & (FALLOC_FL_PUNCH_HOLE | FALLOC_FL_COLLAPSE_RANGE |
+			FALLOC_FL_ZERO_RANGE | FALLOC_FL_INSERT_RANGE)))
 		return -EOPNOTSUPP;
 
 	if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE |
···
 			return -ENOTEMPTY;
 	}
 
+	if (iflags & (F2FS_COMPR_FL | F2FS_NOCOMP_FL)) {
+		if (!f2fs_sb_has_compression(F2FS_I_SB(inode)))
+			return -EOPNOTSUPP;
+		if ((iflags & F2FS_COMPR_FL) && (iflags & F2FS_NOCOMP_FL))
+			return -EINVAL;
+	}
+
+	if ((iflags ^ fi->i_flags) & F2FS_COMPR_FL) {
+		if (S_ISREG(inode->i_mode) &&
+			(fi->i_flags & F2FS_COMPR_FL || i_size_read(inode) ||
+						F2FS_HAS_BLOCKS(inode)))
+			return -EINVAL;
+		if (iflags & F2FS_NOCOMP_FL)
+			return -EINVAL;
+		if (iflags & F2FS_COMPR_FL) {
+			int err = f2fs_convert_inline_inode(inode);
+
+			if (err)
+				return err;
+
+			if (!f2fs_may_compress(inode))
+				return -EINVAL;
+
+			set_compress_context(inode);
+		}
+	}
+	if ((iflags ^ fi->i_flags) & F2FS_NOCOMP_FL) {
+		if (fi->i_flags & F2FS_COMPR_FL)
+			return -EINVAL;
+	}
+
 	fi->i_flags = iflags | (fi->i_flags & ~mask);
+	f2fs_bug_on(F2FS_I_SB(inode), (fi->i_flags & F2FS_COMPR_FL) &&
+					(fi->i_flags & F2FS_NOCOMP_FL));
 
 	if (fi->i_flags & F2FS_PROJINHERIT_FL)
 		set_inode_flag(inode, FI_PROJ_INHERIT);
···
 	u32 iflag;
 	u32 fsflag;
 } f2fs_fsflags_map[] = {
+	{ F2FS_COMPR_FL,	FS_COMPR_FL },
 	{ F2FS_SYNC_FL,		FS_SYNC_FL },
 	{ F2FS_IMMUTABLE_FL,	FS_IMMUTABLE_FL },
 	{ F2FS_APPEND_FL,	FS_APPEND_FL },
 	{ F2FS_NODUMP_FL,	FS_NODUMP_FL },
 	{ F2FS_NOATIME_FL,	FS_NOATIME_FL },
+	{ F2FS_NOCOMP_FL,	FS_NOCOMP_FL },
 	{ F2FS_INDEX_FL,	FS_INDEX_FL },
 	{ F2FS_DIRSYNC_FL,	FS_DIRSYNC_FL },
 	{ F2FS_PROJINHERIT_FL,	FS_PROJINHERIT_FL },
···
 };
 
 #define F2FS_GETTABLE_FS_FL (		\
+		FS_COMPR_FL |		\
 		FS_SYNC_FL |		\
 		FS_IMMUTABLE_FL |	\
 		FS_APPEND_FL |		\
 		FS_NODUMP_FL |		\
 		FS_NOATIME_FL |		\
+		FS_NOCOMP_FL |		\
 		FS_INDEX_FL |		\
 		FS_DIRSYNC_FL |		\
 		FS_PROJINHERIT_FL |	\
···
 		FS_CASEFOLD_FL)
 
 #define F2FS_SETTABLE_FS_FL (		\
+		FS_COMPR_FL |		\
 		FS_SYNC_FL |		\
 		FS_IMMUTABLE_FL |	\
 		FS_APPEND_FL |		\
 		FS_NODUMP_FL |		\
 		FS_NOATIME_FL |		\
+		FS_NOCOMP_FL |		\
 		FS_DIRSYNC_FL |		\
 		FS_PROJINHERIT_FL |	\
 		FS_CASEFOLD_FL)
···
 		return ret;
 
 	inode_lock(inode);
+
+	f2fs_disable_compressed_file(inode);
 
 	if (f2fs_is_atomic_file(inode)) {
 		if (is_inode_flag_set(inode, FI_ATOMIC_REVOKE_REQUEST))
···
 		ret = -EAGAIN;
 		goto out;
 	}
+
 	ret = f2fs_convert_inline_inode(inode);
 	if (ret)
 		goto out;
+
+	if (f2fs_disable_compressed_file(inode)) {
+		ret = -EOPNOTSUPP;
+		goto out;
+	}
 
 	set_inode_flag(inode, FI_PIN_FILE);
 	ret = F2FS_I(inode)->i_gc_failures[GC_FAILURE_PIN];
···
 	}
 }
 
+static ssize_t f2fs_file_read_iter(struct kiocb *iocb, struct iov_iter *iter)
+{
+	struct file *file = iocb->ki_filp;
+	struct inode *inode = file_inode(file);
+
+	if (!f2fs_is_compress_backend_ready(inode))
+		return -EOPNOTSUPP;
+
+	return generic_file_read_iter(iocb, iter);
+}
+
 static ssize_t f2fs_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
 {
 	struct file *file = iocb->ki_filp;
···
 		ret = -EIO;
 		goto out;
 	}
+
+	if (!f2fs_is_compress_backend_ready(inode))
+		return -EOPNOTSUPP;
 
 	if (iocb->ki_flags & IOCB_NOWAIT) {
 		if (!inode_trylock(inode)) {
···
 
 const struct file_operations f2fs_file_operations = {
 	.llseek		= f2fs_llseek,
-	.read_iter	= generic_file_read_iter,
+	.read_iter	= f2fs_file_read_iter,
 	.write_iter	= f2fs_file_write_iter,
 	.open		= f2fs_file_open,
 	.release	= f2fs_release_file,

fs/f2fs/inode.c

···
 {
 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
 	struct f2fs_inode_info *fi = F2FS_I(inode);
+	struct f2fs_inode *ri = F2FS_INODE(node_page);
 	unsigned long long iblocks;
 
 	iblocks = le64_to_cpu(F2FS_INODE(node_page)->i_blocks);
···
 		f2fs_warn(sbi, "%s: inode (ino=%lx, mode=%u) should not have inline_dentry, run fsck to fix",
 			  __func__, inode->i_ino, inode->i_mode);
 		return false;
+	}
+
+	if (f2fs_has_extra_attr(inode) && f2fs_sb_has_compression(sbi) &&
+			fi->i_flags & F2FS_COMPR_FL &&
+			F2FS_FITS_IN_INODE(ri, fi->i_extra_isize,
+						i_log_cluster_size)) {
+		if (ri->i_compress_algorithm >= COMPRESS_MAX)
+			return false;
+		if (le64_to_cpu(ri->i_compr_blocks) > inode->i_blocks)
+			return false;
+		if (ri->i_log_cluster_size < MIN_COMPRESS_LOG_SIZE ||
+			ri->i_log_cluster_size > MAX_COMPRESS_LOG_SIZE)
+			return false;
 	}
 
 	return true;
···
 		fi->i_crtime.tv_nsec = le32_to_cpu(ri->i_crtime_nsec);
 	}
 
+	if (f2fs_has_extra_attr(inode) && f2fs_sb_has_compression(sbi) &&
+					(fi->i_flags & F2FS_COMPR_FL)) {
+		if (F2FS_FITS_IN_INODE(ri, fi->i_extra_isize,
+					i_log_cluster_size)) {
+			fi->i_compr_blocks = le64_to_cpu(ri->i_compr_blocks);
+			fi->i_compress_algorithm = ri->i_compress_algorithm;
+			fi->i_log_cluster_size = ri->i_log_cluster_size;
+			fi->i_cluster_size = 1 << fi->i_log_cluster_size;
+			set_inode_flag(inode, FI_COMPRESSED_FILE);
+		}
+	}
+
 	F2FS_I(inode)->i_disk_time[0] = inode->i_atime;
 	F2FS_I(inode)->i_disk_time[1] = inode->i_ctime;
 	F2FS_I(inode)->i_disk_time[2] = inode->i_mtime;
···
 	stat_inc_inline_xattr(inode);
 	stat_inc_inline_inode(inode);
 	stat_inc_inline_dir(inode);
+	stat_inc_compr_inode(inode);
+	stat_add_compr_blocks(inode, F2FS_I(inode)->i_compr_blocks);
 
 	return 0;
 }
···
 			ri->i_crtime_nsec =
 				cpu_to_le32(F2FS_I(inode)->i_crtime.tv_nsec);
 		}
+
+		if (f2fs_sb_has_compression(F2FS_I_SB(inode)) &&
+			F2FS_FITS_IN_INODE(ri, F2FS_I(inode)->i_extra_isize,
+							i_log_cluster_size)) {
+			ri->i_compr_blocks =
+				cpu_to_le64(F2FS_I(inode)->i_compr_blocks);
+			ri->i_compress_algorithm =
+				F2FS_I(inode)->i_compress_algorithm;
+			ri->i_log_cluster_size =
+				F2FS_I(inode)->i_log_cluster_size;
+		}
 	}
 
 	__set_inode_rdev(inode, ri);
···
 	stat_dec_inline_xattr(inode);
 	stat_dec_inline_dir(inode);
 	stat_dec_inline_inode(inode);
+	stat_dec_compr_inode(inode);
+	stat_sub_compr_blocks(inode, F2FS_I(inode)->i_compr_blocks);
 
 	if (likely(!f2fs_cp_error(sbi) &&
 				!is_sbi_flag_set(sbi, SBI_CP_DISABLED)))

fs/f2fs/namei.c

···
 	if (F2FS_I(inode)->i_flags & F2FS_PROJINHERIT_FL)
 		set_inode_flag(inode, FI_PROJ_INHERIT);
 
+	if (f2fs_sb_has_compression(sbi)) {
+		/* Inherit the compression flag in directory */
+		if ((F2FS_I(dir)->i_flags & F2FS_COMPR_FL) &&
+					f2fs_may_compress(inode))
+			set_compress_context(inode);
+	}
+
 	f2fs_set_inode_flags(inode);
 
 	trace_f2fs_new_inode(inode, 0);
···
 	size_t slen = strlen(s);
 	size_t sublen = strlen(sub);
 	int i;
+
+	if (sublen == 1 && *sub == '*')
+		return 1;
 
 	/*
 	 * filename format of multimedia file should be defined as:
···
 	return 0;
 }
 
+static void set_compress_inode(struct f2fs_sb_info *sbi, struct inode *inode,
+						const unsigned char *name)
+{
+	__u8 (*extlist)[F2FS_EXTENSION_LEN] = sbi->raw_super->extension_list;
+	unsigned char (*ext)[F2FS_EXTENSION_LEN];
+	unsigned int ext_cnt = F2FS_OPTION(sbi).compress_ext_cnt;
+	int i, cold_count, hot_count;
+
+	if (!f2fs_sb_has_compression(sbi) ||
+			is_inode_flag_set(inode, FI_COMPRESSED_FILE) ||
+			F2FS_I(inode)->i_flags & F2FS_NOCOMP_FL ||
+			!f2fs_may_compress(inode))
+		return;
+
+	down_read(&sbi->sb_lock);
+
+	cold_count = le32_to_cpu(sbi->raw_super->extension_count);
+	hot_count = sbi->raw_super->hot_ext_count;
+
+	for (i = cold_count; i < cold_count + hot_count; i++) {
+		if (is_extension_exist(name, extlist[i])) {
+			up_read(&sbi->sb_lock);
+			return;
+		}
+	}
+
+	up_read(&sbi->sb_lock);
+
+	ext = F2FS_OPTION(sbi).extensions;
+
+	for (i = 0; i < ext_cnt; i++) {
+		if (!is_extension_exist(name, ext[i]))
+			continue;
+
+		set_compress_context(inode);
+		return;
+	}
+}
+
 static int f2fs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
 						bool excl)
 {
···
 
 	if (!test_opt(sbi, DISABLE_EXT_IDENTIFY))
 		set_file_temperature(sbi, inode, dentry->d_name.name);
+
+	set_compress_inode(sbi, inode, dentry->d_name.name);
 
 	inode->i_op = &f2fs_file_inode_operations;
 	inode->i_fop = &f2fs_file_operations;

fs/f2fs/segment.c

···
 	struct sit_info *sit_i = SIT_I(sbi);
 
 	f2fs_bug_on(sbi, addr == NULL_ADDR);
-	if (addr == NEW_ADDR)
+	if (addr == NEW_ADDR || addr == COMPRESS_ADDR)
 		return;
 
 	invalidate_mapping_pages(META_MAPPING(sbi), addr, addr);
···
 	if (fio->type == DATA) {
 		struct inode *inode = fio->page->mapping->host;
 
-		if (is_cold_data(fio->page) || file_is_cold(inode))
+		if (is_cold_data(fio->page) || file_is_cold(inode) ||
+				f2fs_compressed_file(inode))
 			return CURSEG_COLD_DATA;
 		if (file_is_hot(inode) ||
 				is_inode_flag_set(inode, FI_HOT_DATA) ||

fs/f2fs/segment.h

···
 	void (*allocate_segment)(struct f2fs_sb_info *, int, bool);
 };
 
-/*
- * this value is set in page as a private data which indicate that
- * the page is atomically written, and it is in inmem_pages list.
- */
-#define ATOMIC_WRITTEN_PAGE		((unsigned long)-1)
-#define DUMMY_WRITTEN_PAGE		((unsigned long)-2)
-
-#define IS_ATOMIC_WRITTEN_PAGE(page)			\
-		(page_private(page) == (unsigned long)ATOMIC_WRITTEN_PAGE)
-#define IS_DUMMY_WRITTEN_PAGE(page)			\
-		(page_private(page) == (unsigned long)DUMMY_WRITTEN_PAGE)
-
 #define MAX_SKIP_GC_COUNT			16
 
 struct inmem_pages {

fs/f2fs/super.c

···
 	Opt_checkpoint_disable_cap,
 	Opt_checkpoint_disable_cap_perc,
 	Opt_checkpoint_enable,
+	Opt_compress_algorithm,
+	Opt_compress_log_size,
+	Opt_compress_extension,
 	Opt_err,
 };
 
···
 	{Opt_checkpoint_disable_cap, "checkpoint=disable:%u"},
 	{Opt_checkpoint_disable_cap_perc, "checkpoint=disable:%u%%"},
 	{Opt_checkpoint_enable, "checkpoint=enable"},
+	{Opt_compress_algorithm, "compress_algorithm=%s"},
+	{Opt_compress_log_size, "compress_log_size=%u"},
+	{Opt_compress_extension, "compress_extension=%s"},
 	{Opt_err, NULL},
 };
 
···
 {
 	struct f2fs_sb_info *sbi = F2FS_SB(sb);
 	substring_t args[MAX_OPT_ARGS];
+	unsigned char (*ext)[F2FS_EXTENSION_LEN];
 	char *p, *name;
-	int arg = 0;
+	int arg = 0, ext_cnt;
 	kuid_t uid;
 	kgid_t gid;
 #ifdef CONFIG_QUOTA
···
 		case Opt_checkpoint_enable:
 			clear_opt(sbi, DISABLE_CHECKPOINT);
 			break;
+		case Opt_compress_algorithm:
+			if (!f2fs_sb_has_compression(sbi)) {
+				f2fs_err(sbi, "Compression feature if off");
+				return -EINVAL;
+			}
+			name = match_strdup(&args[0]);
+			if (!name)
+				return -ENOMEM;
+			if (strlen(name) == 3 && !strcmp(name, "lzo")) {
+				F2FS_OPTION(sbi).compress_algorithm =
+								COMPRESS_LZO;
+			} else if (strlen(name) == 3 &&
+					!strcmp(name, "lz4")) {
+				F2FS_OPTION(sbi).compress_algorithm =
+								COMPRESS_LZ4;
+			} else {
+				kfree(name);
+				return -EINVAL;
+			}
+			kfree(name);
+			break;
+		case Opt_compress_log_size:
+			if (!f2fs_sb_has_compression(sbi)) {
+				f2fs_err(sbi, "Compression feature is off");
+				return -EINVAL;
+			}
+			if (args->from && match_int(args, &arg))
+				return -EINVAL;
+			if (arg < MIN_COMPRESS_LOG_SIZE ||
+				arg > MAX_COMPRESS_LOG_SIZE) {
+				f2fs_err(sbi,
+					"Compress cluster log size is out of range");
+				return -EINVAL;
+			}
+			F2FS_OPTION(sbi).compress_log_size = arg;
+			break;
+		case Opt_compress_extension:
+			if (!f2fs_sb_has_compression(sbi)) {
+				f2fs_err(sbi, "Compression feature is off");
+				return -EINVAL;
+			}
+			name = match_strdup(&args[0]);
+			if (!name)
+				return -ENOMEM;
+
+			ext = F2FS_OPTION(sbi).extensions;
+			ext_cnt = F2FS_OPTION(sbi).compress_ext_cnt;
+
+			if (strlen(name) >= F2FS_EXTENSION_LEN ||
+				ext_cnt >= COMPRESS_EXT_NUM) {
+				f2fs_err(sbi,
+					"invalid extension length/number");
+				kfree(name);
+				return -EINVAL;
+			}
+
+			strcpy(ext[ext_cnt], name);
+			F2FS_OPTION(sbi).compress_ext_cnt++;
+			kfree(name);
+			break;
 		default:
 			f2fs_err(sbi, "Unrecognized mount option \"%s\" or missing value",
 				 p);
···
 	f2fs_destroy_node_manager(sbi);
 	f2fs_destroy_segment_manager(sbi);
 
+	f2fs_destroy_post_read_wq(sbi);
+
 	kvfree(sbi->ckpt);
 
 	f2fs_unregister_sysfs(sbi);
···
 #endif
 }
 
+static inline void f2fs_show_compress_options(struct seq_file *seq,
+							struct super_block *sb)
+{
+	struct f2fs_sb_info *sbi = F2FS_SB(sb);
+	char *algtype = "";
+	int i;
+
+	if (!f2fs_sb_has_compression(sbi))
+		return;
+
+	switch (F2FS_OPTION(sbi).compress_algorithm) {
+	case COMPRESS_LZO:
+		algtype = "lzo";
+		break;
+	case COMPRESS_LZ4:
+		algtype = "lz4";
+		break;
+	}
+	seq_printf(seq, ",compress_algorithm=%s", algtype);
+
+	seq_printf(seq, ",compress_log_size=%u",
+			F2FS_OPTION(sbi).compress_log_size);
+
+	for (i = 0; i < F2FS_OPTION(sbi).compress_ext_cnt; i++) {
+		seq_printf(seq, ",compress_extension=%s",
+			F2FS_OPTION(sbi).extensions[i]);
+	}
+}
+
 static int f2fs_show_options(struct seq_file *seq, struct dentry *root)
 {
 	struct f2fs_sb_info *sbi = F2FS_SB(root->d_sb);
···
 		seq_printf(seq, ",fsync_mode=%s", "strict");
 	else if (F2FS_OPTION(sbi).fsync_mode == FSYNC_MODE_NOBARRIER)
 		seq_printf(seq, ",fsync_mode=%s", "nobarrier");
+
+	f2fs_show_compress_options(seq, sbi->sb);
 	return 0;
 }
 
···
 	F2FS_OPTION(sbi).test_dummy_encryption = false;
 	F2FS_OPTION(sbi).s_resuid = make_kuid(&init_user_ns, F2FS_DEF_RESUID);
 	F2FS_OPTION(sbi).s_resgid = make_kgid(&init_user_ns, F2FS_DEF_RESGID);
+	F2FS_OPTION(sbi).compress_algorithm = COMPRESS_LZO;
+	F2FS_OPTION(sbi).compress_log_size = MIN_COMPRESS_LOG_SIZE;
+	F2FS_OPTION(sbi).compress_ext_cnt = 0;
 
 	set_opt(sbi, BG_GC);
 	set_opt(sbi, INLINE_XATTR);
···
 		goto free_devices;
 	}
 
+	err = f2fs_init_post_read_wq(sbi);
+	if (err) {
+		f2fs_err(sbi, "Failed to initialize post read workqueue");
+		goto free_devices;
+	}
+
 	sbi->total_valid_node_count =
 				le32_to_cpu(sbi->ckpt->valid_node_count);
 	percpu_counter_set(&sbi->total_valid_inode_count,
···
 	f2fs_destroy_node_manager(sbi);
 free_sm:
 	f2fs_destroy_segment_manager(sbi);
+	f2fs_destroy_post_read_wq(sbi);
 free_devices:
 	destroy_device_list(sbi);
 	kvfree(sbi->ckpt);

fs/f2fs/sysfs.c

···
 	if (f2fs_sb_has_casefold(sbi))
 		len += snprintf(buf + len, PAGE_SIZE - len, "%s%s",
 				len ? ", " : "", "casefold");
+	if (f2fs_sb_has_compression(sbi))
+		len += snprintf(buf + len, PAGE_SIZE - len, "%s%s",
+				len ? ", " : "", "compression");
 	len += snprintf(buf + len, PAGE_SIZE - len, "%s%s",
 				len ? ", " : "", "pin_file");
 	len += snprintf(buf + len, PAGE_SIZE - len, "\n");
···
 	FEAT_VERITY,
 	FEAT_SB_CHECKSUM,
 	FEAT_CASEFOLD,
+	FEAT_COMPRESSION,
 };
 
 static ssize_t f2fs_feature_show(struct f2fs_attr *a,
···
 	case FEAT_VERITY:
 	case FEAT_SB_CHECKSUM:
 	case FEAT_CASEFOLD:
+	case FEAT_COMPRESSION:
 		return snprintf(buf, PAGE_SIZE, "supported\n");
 	}
 	return 0;
···
 #endif
 F2FS_FEATURE_RO_ATTR(sb_checksum, FEAT_SB_CHECKSUM);
 F2FS_FEATURE_RO_ATTR(casefold, FEAT_CASEFOLD);
+F2FS_FEATURE_RO_ATTR(compression, FEAT_COMPRESSION);
 
 #define ATTR_LIST(name) (&f2fs_attr_##name.attr)
 static struct attribute *f2fs_attrs[] = {
···
 #endif
 	ATTR_LIST(sb_checksum),
 	ATTR_LIST(casefold),
+	ATTR_LIST(compression),
 	NULL,
 };
 ATTRIBUTE_GROUPS(f2fs_feat);

include/linux/f2fs_fs.h

···
 
 #define NULL_ADDR		((block_t)0)	/* used as block_t addresses */
 #define NEW_ADDR		((block_t)-1)	/* used as block_t addresses */
+#define COMPRESS_ADDR		((block_t)-2)	/* used as compressed data flag */
 
 #define F2FS_BYTES_TO_BLK(bytes)	((bytes) >> F2FS_BLKSIZE_BITS)
 #define F2FS_BLK_TO_BYTES(blk)		((blk) << F2FS_BLKSIZE_BITS)
···
 			__le32 i_inode_checksum;/* inode meta checksum */
 			__le64 i_crtime;	/* creation time */
 			__le32 i_crtime_nsec;	/* creation time in nano scale */
+			__le64 i_compr_blocks;	/* # of compressed blocks */
+			__u8 i_compress_algorithm;	/* compress algorithm */
+			__u8 i_log_cluster_size;	/* log of cluster size */
+			__le16 i_padding;		/* padding */
 			__le32 i_extra_end[0];	/* for attribute size calculation */
 		} __packed;
 		__le32 i_addr[DEF_ADDRS_PER_INODE];	/* Pointers to data blocks */

include/trace/events/f2fs.h

···
 	__print_symbolic(type,						\
 		{ CP_NO_NEEDED,		"no needed" },			\
 		{ CP_NON_REGULAR,	"non regular" },		\
+		{ CP_COMPRESSED,	"compreesed" },			\
 		{ CP_HARDLINK,		"hardlink" },			\
 		{ CP_SB_NEED_CP,	"sb needs cp" },		\
 		{ CP_WRONG_PINO,	"wrong pino" },			\
···
 		{ F2FS_GOING_DOWN_NOSYNC,	"no sync" },		\
 		{ F2FS_GOING_DOWN_METAFLUSH,	"meta flush" },		\
 		{ F2FS_GOING_DOWN_NEED_FSCK,	"need fsck" })
+
+#define show_compress_algorithm(type)					\
+	__print_symbolic(type,						\
+		{ COMPRESS_LZO,		"LZO" },			\
+		{ COMPRESS_LZ4,		"LZ4" })
 
 struct f2fs_sb_info;
 struct f2fs_io_info;
···
 		show_dev(__entry->dev),
 		show_shutdown_mode(__entry->mode),
 		__entry->ret)
+);
+
+DECLARE_EVENT_CLASS(f2fs_zip_start,
+
+	TP_PROTO(struct inode *inode, pgoff_t cluster_idx,
+			unsigned int cluster_size, unsigned char algtype),
+
+	TP_ARGS(inode, cluster_idx, cluster_size, algtype),
+
+	TP_STRUCT__entry(
+		__field(dev_t,	dev)
+		__field(ino_t,	ino)
+		__field(pgoff_t, idx)
+		__field(unsigned int, size)
+		__field(unsigned int, algtype)
+	),
+
+	TP_fast_assign(
+		__entry->dev = inode->i_sb->s_dev;
+		__entry->ino = inode->i_ino;
+		__entry->idx = cluster_idx;
+		__entry->size = cluster_size;
+		__entry->algtype = algtype;
+	),
+
+	TP_printk("dev = (%d,%d), ino = %lu, cluster_idx:%lu, "
+		"cluster_size = %u, algorithm = %s",
+		show_dev_ino(__entry),
+		__entry->idx,
+		__entry->size,
+		show_compress_algorithm(__entry->algtype))
+);
+
+DECLARE_EVENT_CLASS(f2fs_zip_end,
+
+	TP_PROTO(struct inode *inode, pgoff_t cluster_idx,
+			unsigned int compressed_size, int ret),
+
+	TP_ARGS(inode, cluster_idx, compressed_size, ret),
+
+	TP_STRUCT__entry(
+		__field(dev_t,	dev)
+		__field(ino_t,	ino)
+		__field(pgoff_t, idx)
+		__field(unsigned int, size)
+		__field(unsigned int, ret)
+	),
+
+	TP_fast_assign(
+		__entry->dev = inode->i_sb->s_dev;
+		__entry->ino = inode->i_ino;
+		__entry->idx = cluster_idx;
+		__entry->size = compressed_size;
+		__entry->ret = ret;
+	),
+
+	TP_printk("dev = (%d,%d), ino = %lu, cluster_idx:%lu, "
+		"compressed_size = %u, ret = %d",
+		show_dev_ino(__entry),
+		__entry->idx,
+		__entry->size,
+		__entry->ret)
+);
+
+DEFINE_EVENT(f2fs_zip_start, f2fs_compress_pages_start,
+
+	TP_PROTO(struct inode *inode, pgoff_t cluster_idx,
+		unsigned int cluster_size, unsigned char algtype),
+
+	TP_ARGS(inode, cluster_idx, cluster_size, algtype)
+);
+
+DEFINE_EVENT(f2fs_zip_start, f2fs_decompress_pages_start,
+
+	TP_PROTO(struct inode *inode, pgoff_t cluster_idx,
+		unsigned int cluster_size, unsigned char algtype),
+
+	TP_ARGS(inode, cluster_idx, cluster_size, algtype)
+);
+
+DEFINE_EVENT(f2fs_zip_end, f2fs_compress_pages_end,
+
+	TP_PROTO(struct inode *inode, pgoff_t cluster_idx,
+			unsigned int compressed_size, int ret),
+
+	TP_ARGS(inode, cluster_idx, compressed_size, ret)
+);
+
+DEFINE_EVENT(f2fs_zip_end, f2fs_decompress_pages_end,
+
+	TP_PROTO(struct inode *inode, pgoff_t cluster_idx,
+			unsigned int compressed_size, int ret),
+
+	TP_ARGS(inode, cluster_idx, compressed_size, ret)
 );
 
 #endif /* _TRACE_F2FS_H */