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: <noreply@ellerman.id.au>
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

1 files changed, 550 insertions, 74 deletions

diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index f89aeaaea90e..98c946dfee13 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -82,6 +82,9 @@ static bool __is_cp_guaranteed(struct page *page)
 	if (!mapping)
 		return false;
 
+	if (f2fs_is_compressed_page(page))
+		return false;
+
 	inode = mapping->host;
 	sbi = F2FS_I_SB(inode);
 
@@ -114,19 +117,19 @@ static enum count_type __read_io_type(struct page *page)
 
 /* 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;
@@ -135,6 +138,13 @@ static void __read_end_io(struct bio *bio)
 	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)) {
 			ClearPageUptodate(page);
@@ -146,31 +156,94 @@ static void __read_end_io(struct bio *bio)
 		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)
+{
+	fscrypt_decrypt_bio(ctx->bio);
+}
+
+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);
 
-	fscrypt_decrypt_bio(ctx->bio);
+#ifdef CONFIG_F2FS_FS_COMPRESSION
+	/* previous step is decompression */
+	if (ctx->enabled_steps & (1 << STEP_DECOMPRESS)) {
+
+		f2fs_verify_bio(ctx->bio);
+		f2fs_release_read_bio(ctx->bio);
+		return;
+	}
+#endif
 
-	bio_post_read_processing(ctx);
+	fsverity_verify_bio(ctx->bio);
+	__f2fs_read_end_io(ctx->bio, false, false);
 }
 
-static void verity_work(struct work_struct *work)
+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);
 
-	fsverity_verify_bio(ctx->bio);
+	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);
+}
 
-	bio_post_read_processing(ctx);
+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)
@@ -180,31 +253,26 @@ 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)
@@ -219,12 +287,11 @@ 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)
@@ -255,6 +322,13 @@ 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);
 			if (type == F2FS_WB_CP_DATA)
@@ -399,6 +473,12 @@ submit_io:
 	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;
@@ -421,7 +501,6 @@ static bool __has_merged_page(struct bio *bio, struct inode *inode,
 						struct page *page, nid_t ino)
 {
 	struct bio_vec *bvec;
-	struct page *target;
 	struct bvec_iter_all iter_all;
 
 	if (!bio)
@@ -431,10 +510,18 @@ static bool __has_merged_page(struct bio *bio, struct inode *inode,
 		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;
@@ -629,7 +716,8 @@ static int add_ipu_page(struct f2fs_sb_info *sbi, struct bio **bio,
 
 			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;
 			}
@@ -769,7 +857,12 @@ next:
 
 	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;
@@ -838,7 +931,8 @@ static struct bio *f2fs_grab_read_bio(struct inode *inode, block_t blkaddr,
 
 	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;
 
@@ -849,6 +943,7 @@ static struct bio *f2fs_grab_read_bio(struct inode *inode, block_t blkaddr,
 			return ERR_PTR(-ENOMEM);
 		}
 		ctx->bio = bio;
+		ctx->sbi = sbi;
 		ctx->enabled_steps = post_read_steps;
 		bio->bi_private = ctx;
 	}
@@ -856,6 +951,13 @@ static struct bio *f2fs_grab_read_bio(struct inode *inode, block_t blkaddr,
 	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 */
 static int f2fs_submit_page_read(struct inode *inode, struct page *page,
 							block_t blkaddr)
@@ -1900,6 +2002,144 @@ out:
 	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.
@@ -1909,7 +2149,7 @@ out:
  * 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)
 {
@@ -1917,6 +2157,19 @@ static int f2fs_mpage_readpages(struct address_space *mapping,
 	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;
@@ -1940,9 +2193,41 @@ static int f2fs_mpage_readpages(struct address_space *mapping,
 				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);
@@ -1950,6 +2235,19 @@ static int f2fs_mpage_readpages(struct address_space *mapping,
 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)
@@ -1964,6 +2262,11 @@ static int f2fs_read_data_page(struct file *file, struct page *page)
 
 	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))
 		ret = f2fs_read_inline_data(inode, page);
@@ -1982,6 +2285,9 @@ static int f2fs_read_data_pages(struct file *file,
 
 	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;
@@ -1989,22 +2295,23 @@ static int f2fs_read_data_pages(struct file *file,
 	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) {
@@ -2164,7 +2471,7 @@ got_it:
 	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;
 
@@ -2200,13 +2507,16 @@ got_it:
 
 	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);
 	trace_f2fs_do_write_data_page(page, OPU);
@@ -2221,16 +2531,17 @@ out:
 	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;
@@ -2246,6 +2557,7 @@ static int __write_data_page(struct page *page, bool *submitted,
 		.page = page,
 		.encrypted_page = NULL,
 		.submitted = false,
+		.compr_blocks = compr_blocks,
 		.need_lock = LOCK_RETRY,
 		.io_type = io_type,
 		.io_wbc = wbc,
@@ -2270,7 +2582,9 @@ static int __write_data_page(struct page *page, bool *submitted,
 	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;
 
 	/*
@@ -2346,7 +2660,6 @@ out:
 		f2fs_remove_dirty_inode(inode);
 		submitted = NULL;
 	}
-
 	unlock_page(page);
 	if (!S_ISDIR(inode->i_mode) && !IS_NOQUOTA(inode) &&
 					!F2FS_I(inode)->cp_task)
@@ -2359,7 +2672,7 @@ out:
 	}
 
 	if (submitted)
-		*submitted = fio.submitted;
+		*submitted = fio.submitted ? 1 : 0;
 
 	return 0;
 
@@ -2380,7 +2693,23 @@ redirty_out:
 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);
 }
 
 /*
@@ -2393,11 +2722,27 @@ static int f2fs_write_cache_pages(struct address_space *mapping,
 					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;
@@ -2407,6 +2752,8 @@ static int f2fs_write_cache_pages(struct address_space *mapping,
 	int range_whole = 0;
 	xa_mark_t tag;
 	int nwritten = 0;
+	int submitted = 0;
+	int i;
 
 	pagevec_init(&pvec);
 
@@ -2436,12 +2783,11 @@ static int f2fs_write_cache_pages(struct address_space *mapping,
 	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)
@@ -2449,15 +2795,62 @@ retry:
 
 		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);
@@ -2484,45 +2877,71 @@ continue_unlock:
 			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;
@@ -2546,6 +2965,8 @@ static inline bool __should_serialize_io(struct inode *inode,
 {
 	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 */
@@ -2690,6 +3111,7 @@ static int prepare_write_begin(struct f2fs_sb_info *sbi,
 		__do_map_lock(sbi, flag, true);
 		locked = true;
 	}
+
 restart:
 	/* check inline_data */
 	ipage = f2fs_get_node_page(sbi, inode->i_ino);
@@ -2780,6 +3202,24 @@ static int f2fs_write_begin(struct file *file, struct address_space *mapping,
 		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
@@ -2792,6 +3232,8 @@ repeat:
 		goto fail;
 	}
 
+	/* TODO: cluster can be compressed due to race with .writepage */
+
 	*pagep = page;
 
 	err = prepare_write_begin(sbi, page, pos, len,
@@ -2875,6 +3317,16 @@ static int f2fs_write_end(struct file *file,
 		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;
 
@@ -3265,6 +3717,9 @@ static int f2fs_swap_activate(struct swap_info_struct *sis, struct file *file,
 	if (ret)
 		return ret;
 
+	if (f2fs_disable_compressed_file(inode))
+		return -EINVAL;
+
 	ret = check_swap_activate(file, sis->max);
 	if (ret)
 		return ret;
@@ -3349,6 +3804,27 @@ void f2fs_destroy_post_read_processing(void)
 	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)
 {
 	bio_entry_slab = f2fs_kmem_cache_create("bio_entry_slab",