On 11/01, Jaegeuk Kim wrote:
> On 11/01, Jaegeuk Kim wrote:
> > On 11/01, Chao Yu wrote:
> > > 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
> > > 
> > > [Jaegeuk Kim]
> > > - add tracepoint for f2fs_{,de}compress_pages()
> > > - fix many bugs and add some compression stats
> > > 
> > > Signed-off-by: Chao Yu <yuch...@huawei.com>
> > > Signed-off-by: Jaegeuk Kim <jaeg...@kernel.org>
> > > ---
> > >  Documentation/filesystems/f2fs.txt |   52 ++
> > >  fs/f2fs/Kconfig                    |   23 +
> > >  fs/f2fs/Makefile                   |    1 +
> > >  fs/f2fs/compress.c                 | 1098 ++++++++++++++++++++++++++++
> > >  fs/f2fs/data.c                     |  549 ++++++++++++--
> > >  fs/f2fs/debug.c                    |    6 +
> > >  fs/f2fs/f2fs.h                     |  245 ++++++-
> > >  fs/f2fs/file.c                     |  191 ++++-
> > >  fs/f2fs/inode.c                    |   43 ++
> > >  fs/f2fs/namei.c                    |   59 ++
> > >  fs/f2fs/segment.c                  |    5 +-
> > >  fs/f2fs/segment.h                  |   12 -
> > >  fs/f2fs/super.c                    |  112 ++-
> > >  fs/f2fs/sysfs.c                    |    7 +
> > >  include/linux/f2fs_fs.h            |   11 +
> > >  include/trace/events/f2fs.h        |   99 +++
> > >  16 files changed, 2397 insertions(+), 116 deletions(-)
> > >  create mode 100644 fs/f2fs/compress.c
> > > 
> > > diff --git a/Documentation/filesystems/f2fs.txt 
> > > b/Documentation/filesystems/f2fs.txt
> > > index 29020af0cff9..228af93f850b 100644
> > > --- a/Documentation/filesystems/f2fs.txt
> > > +++ b/Documentation/filesystems/f2fs.txt
> > > @@ -235,6 +235,17 @@ checkpoint=%s[:%u[%]]     Set to "disable" to turn 
> > > off checkpointing. Set to "en
> > >                         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
> > > @@ -837,3 +848,44 @@ zero or random data, which is useful to the below 
> > > scenario where:
> > >   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      
> > >  |
> > > +      
> > > +-------------+-------------+----------+----------------------------+
> > > diff --git a/fs/f2fs/Kconfig b/fs/f2fs/Kconfig
> > > index 652fd2e2b23d..6087a5577613 100644
> > > --- a/fs/f2fs/Kconfig
> > > +++ b/fs/f2fs/Kconfig
> > > @@ -92,3 +92,26 @@ config F2FS_FAULT_INJECTION
> > >     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" if 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" if F2FS_FS_COMPRESSION
> > > + select LZ4_COMPRESS
> > > + select LZ4_DECOMPRESS
> > > + default y
> > > + help
> > > +   Support LZ4 compress algorithm, if unsure, say Y.
> > > diff --git a/fs/f2fs/Makefile b/fs/f2fs/Makefile
> > > index 2aaecc63834f..ee7316b42f69 100644
> > > --- a/fs/f2fs/Makefile
> > > +++ b/fs/f2fs/Makefile
> > > @@ -9,3 +9,4 @@ f2fs-$(CONFIG_F2FS_FS_XATTR) += xattr.o
> > >  f2fs-$(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
> > > diff --git a/fs/f2fs/compress.c b/fs/f2fs/compress.c
> > > new file mode 100644
> > > index 000000000000..5e65aef72c46
> > > --- /dev/null
> > > +++ b/fs/f2fs/compress.c
> > > @@ -0,0 +1,1098 @@
> > > +// SPDX-License-Identifier: GPL-2.0
> > > +/*
> > > + * f2fs compress support
> > > + *
> > > + * Copyright (c) 2019 Chao Yu <c...@kernel.org>
> > > + */
> > > +
> > > +#include <linux/fs.h>
> > > +#include <linux/f2fs_fs.h>
> > > +#include <linux/writeback.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 unsigned int cluster_idx(struct compress_ctx *cc, pgoff_t index)
> > > +{
> > > + return index >> cc->log_cluster_size;
> > > +}
> > > +
> > > +static unsigned int 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->i_mapping),
> 
> Fixed using page->mapping.
> 
> > > +         *((u32 *)page_private(page)) == F2FS_COMPRESSED_PAGE_MAGIC);

Should
                *((u32 *)page_private(page)) != F2FS_COMPRESSED_PAGE_MAGIC);

All were updated into github.

> > > + 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);
> > > +}
> > > +
> > > +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);
> > > + if (!cc->rpages)
> > > +         return -ENOMEM;
> > > + return 0;
> > > +}
> > > +
> > > +void f2fs_destroy_compress_ctx(struct compress_ctx *cc)
> > > +{
> > > + f2fs_reset_compress_ctx(cc);
> > > + kfree(cc->rpages);
> > > +}
> > > +
> > > +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(cc->inode), 1);
> 
> Fixed using F2FS_I_SB(cc->inode).
> 
> Up-to-date patch is here.
> https://github.com/jaegeuk/f2fs/commit/2c5f2b5d41ad5eb288aa281c8ff008882d0ae42b
> 
> I'm going to test a bit, so please post patches separately for a while, if
> exists. :)
> 
> Thanks,
> 
> > > +
> > > + 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)
> > > +         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:
> > > + f2fs_set_cluster_uptodate(dic->rpages, dic->cluster_size, ret, verity);
> > > + trace_f2fs_decompress_pages_end(dic->inode, dic->cluster_idx,
> > > +                                                         dic->clen, ret);
> > > + 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;
> > > +         if (page->index != start_idx_of_cluster(cc) + i)
> > > +                 return false;
> > > + }
> > > + return true;
> > > +}
> > > +
> > > +int is_compressed_cluster(struct compress_ctx *cc, pgoff_t index)
> > > +{
> > > + struct dnode_of_data dn;
> > > + unsigned int start_idx = cluster_idx(cc, index) <<
> > > +                                 cc->log_cluster_size;
> > > + int ret;
> > > + int i;
> > > +
> > > + set_new_dnode(&dn, cc->inode, NULL, NULL, 0);
> > > + ret = f2fs_get_dnode_of_data(&dn, start_idx, LOOKUP_NODE);
> > > + if (ret) {
> > > +         if (ret == -ENOENT)
> > > +                 ret = 0;
> > > +         goto  fail;
> > 
> > Removed a space.
> > 
> > > + }
> > > +
> > > + if (dn.data_blkaddr == COMPRESS_ADDR) {
> > > +         ret = CLUSTER_IS_FULL;
> > > +         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 = CLUSTER_HAS_SPACE;
> > > +                         break;
> > > +                 }
> > > +         }
> > > + }
> > > +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,
> > > + };
> > > +
> > > + return is_compressed_cluster(&cc, index);
> > > +}
> > > +
> > > +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);
> > > +}
> > > +
> > > +void f2fs_reset_compress_ctx(struct compress_ctx *cc)
> > > +{
> > > + cc->nr_rpages = 0;
> > > + cc->nr_cpages = 0;
> > > + cc->cluster_idx = NULL_CLUSTER;
> > > +}
> > > +
> > > +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,
> > > +         bool prealloc)
> > > +{
> > > + struct f2fs_sb_info *sbi = F2FS_I_SB(cc->inode);
> > > + struct bio *bio = NULL;
> > > + 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;
> > > + unsigned int start_idx = cluster_idx(cc, index) << cc->log_cluster_size;
> > > + int i, idx;
> > > + int ret;
> > > +
> > > + ret = f2fs_init_compress_ctx(cc);
> > > + if (ret)
> > > +         goto out;
> > > +retry:
> > > + /* 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);
> > > +                 continue;
> > > +         }
> > > +
> > > +         f2fs_compress_ctx_add_page(cc, page);
> > > + }
> > > +
> > > + if (!f2fs_cluster_is_empty(cc)) {
> > > +         ret = f2fs_read_multi_pages(cc, &bio, cc->cluster_size,
> > > +                                         &last_block_in_bio, false);
> > > +         if (ret)
> > > +                 goto out;
> > > +
> > > +         if (bio)
> > > +                 f2fs_submit_bio(sbi, bio, DATA);
> > > +
> > > +         ret = f2fs_init_compress_ctx(cc);
> > > +         if (ret)
> > > +                 goto out;
> > > + }
> > > +
> > > + for (i = 0; i < cc->cluster_size; i++) {
> > > +         page = find_lock_page(mapping, start_idx + i);
> > > +         f2fs_bug_on(sbi, !page);
> > > +
> > > +         f2fs_wait_on_page_writeback(page, DATA, true, true);
> > > +
> > > +         cc->rpages[i] = page;
> > > +         f2fs_put_page(page, 0);
> > > +
> > > +         if (!PageUptodate(page)) {
> > > +                 for (idx = i; idx >= 0; idx--) {
> > > +                         f2fs_put_page(cc->rpages[idx], 0);
> > > +                         f2fs_put_page(cc->rpages[idx], 1);
> > > +                 }
> > > +                 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)
> > > +                         /* TODO: release preallocate blocks */
> > > +                         goto release_pages;
> > > +
> > > +                 if (dn.data_blkaddr != NEW_ADDR)
> > > +                         break;
> > > +         }
> > > +
> > > +         __do_map_lock(sbi, F2FS_GET_BLOCK_PRE_AIO, false);
> > > + }
> > > +
> > > + *fsdata = cc->rpages;
> > > + *pagep = cc->rpages[offset_in_cluster(cc, index)];
> > > + return CLUSTER_IS_FULL;
> > > +
> > > +unlock_pages:
> > > + for (idx = 0; idx < i; idx++) {
> > > +         if (cc->rpages[idx])
> > > +                 unlock_page(cc->rpages[idx]);
> > > + }
> > > +release_pages:
> > > + for (idx = 0; idx < i; idx++) {
> > > +         page = find_lock_page(mapping, start_idx + idx);
> > > +         f2fs_put_page(page, 0);
> > > +         f2fs_put_page(page, 1);
> > > + }
> > > + f2fs_destroy_compress_ctx(cc);
> > > +out:
> > > + return ret;
> > > +}
> > > +
> > > +int f2fs_prepare_compress_overwrite(struct inode *inode,
> > > +         struct page **pagep, pgoff_t index, void **fsdata)
> > > +{
> > > + struct compress_ctx cc = {
> > > +         .inode = inode,
> > > +         .cluster_size = F2FS_I(inode)->i_cluster_size,
> > > +         .cluster_idx = NULL_CLUSTER,
> > > +         .rpages = NULL,
> > > +         .nr_rpages = 0,
> > > + };
> > > + int ret = is_compressed_cluster(&cc, index);
> > > +
> > > + if (ret <= 0)
> > > +         return ret;
> > > +
> > > + /* compressed case */
> > > + return prepare_compress_overwrite(&cc, pagep, index,
> > > +                 fsdata, ret == CLUSTER_HAS_SPACE);
> > > +}
> > > +
> > > +bool f2fs_compress_write_end(struct inode *inode, void *fsdata,
> > > +                                 pgoff_t index, bool written)
> > > +
> > > +{
> > > + 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);
> > > + int i;
> > > +
> > > + if (written)
> > > +         set_cluster_dirty(&cc);
> > > +
> > > + for (i = 0; i < cc.cluster_size; i++)
> > > +         f2fs_put_page(cc.rpages[i], 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,
> > > +         .compressed = true,
> > > +         .encrypted = f2fs_encrypted_file(cc->inode),
> > > + };
> > > + struct dnode_of_data dn;
> > > + struct node_info ni;
> > > + struct compress_io_ctx *cic;
> > > + unsigned int start_idx = start_idx_of_cluster(cc);
> > > + unsigned int last_index = cc->cluster_size - 1;
> > > + loff_t psize;
> > > + int pre_compressed_blocks = 0;
> > > + 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;
> > > +
> > > + psize = (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 = cc->rpages;
> > > + 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++, dn.ofs_in_node++) {
> > > +         block_t blkaddr;
> > > +
> > > +         blkaddr = datablock_addr(dn.inode, dn.node_page,
> > > +                                                 dn.ofs_in_node);
> > > +         fio.page = cc->rpages[i];
> > > +         fio.old_blkaddr = blkaddr;
> > > +
> > > +         /* cluster header */
> > > +         if (i == 0) {
> > > +                 if (blkaddr == COMPRESS_ADDR)
> > > +                         pre_compressed_blocks++;
> > > +                 if (__is_valid_data_blkaddr(blkaddr))
> > > +                         f2fs_invalidate_blocks(sbi, blkaddr);
> > > +                 f2fs_update_data_blkaddr(&dn, COMPRESS_ADDR);
> > > +                 goto unlock_continue;
> > > +         }
> > > +
> > > +         if (pre_compressed_blocks && __is_valid_data_blkaddr(blkaddr))
> > > +                 pre_compressed_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 if (fio.compressed)
> > > +                 fio.compressed_page = cc->cpages[i - 1];
> > > +         else
> > > +                 f2fs_bug_on(sbi, 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 (pre_compressed_blocks) {
> > > +         stat_sub_compr_blocks(inode,
> > > +                 cc->cluster_size - pre_compressed_blocks + 1);
> > > +         F2FS_I(inode)->i_compressed_blocks -=
> > > +                 (cc->cluster_size - pre_compressed_blocks + 1);
> > > + }
> > > + stat_add_compr_blocks(inode, cc->cluster_size - cc->nr_cpages);
> > > + F2FS_I(inode)->i_compressed_blocks += cc->cluster_size - cc->nr_cpages;
> > > + f2fs_mark_inode_dirty_sync(inode, 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);
> > > +
> > > + if (err) {
> > > +         file_set_keep_isize(inode);
> > > + } else {
> > > +         down_write(&fi->i_sem);
> > > +         if (fi->last_disk_size < psize)
> > > +                 fi->last_disk_size = psize;
> > > +         up_write(&fi->i_sem);
> > > + }
> > > + return 0;
> > > +
> > > +out_destroy_crypt:
> > > + for (i -= 1; 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_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)
> > > +{
> > > + int i, _submitted;
> > > + int ret, err = 0;
> > > +
> > > + for (i = 0; i < cc->cluster_size; i++) {
> > > +         if (!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);
> > > +         if (ret) {
> > > +                 if (ret == AOP_WRITEPAGE_ACTIVATE)
> > > +                         unlock_page(cc->rpages[i]);
> > > +                 err = ret;
> > > +                 goto out_fail;
> > > +         }
> > > +
> > > +         *submitted += _submitted;
> > > + }
> > > + return 0;
> > > +
> > > +out_fail:
> > > + /* TODO: revoke partially updated block addresses */
> > > + 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 = -EAGAIN;
> > > +
> > > + *submitted = 0;
> > > +
> > > + if (cluster_may_compress(cc)) {
> > > +         err = f2fs_compress_pages(cc);
> > > +         if (err) {
> > > +                 err = -EAGAIN;
> > > +                 goto write;
> > > +         }
> > > +         err = f2fs_write_compressed_pages(cc, submitted,
> > > +                                                 wbc, io_type);
> > > +         cops->destroy_compress_ctx(cc);
> > > + }
> > > +write:
> > > + if (err == -EAGAIN) {
> > > +         bool compressed = false;
> > > +
> > > +         f2fs_bug_on(F2FS_I_SB(cc->inode), *submitted);
> > > +         if (is_compressed_cluster(cc, start_idx_of_cluster(cc)))
> > > +                 compressed = true;
> > > +
> > > +         err = f2fs_write_raw_pages(cc, submitted, wbc, io_type);
> > > +         if (compressed) {
> > > +                 stat_sub_compr_blocks(cc->inode, *submitted);
> > > +                 F2FS_I(cc->inode)->i_compressed_blocks -= *submitted;
> > > +                 f2fs_mark_inode_dirty_sync(cc->inode, true);
> > > +         }
> > > + }
> > > +
> > > + f2fs_reset_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;
> > > + unsigned int start_idx = start_idx_of_cluster(cc);
> > > + int i;
> > > +
> > > + dic = f2fs_kzalloc(sbi, sizeof(struct decompress_io_ctx), GFP_NOFS);
> > > + if (!dic)
> > > +         goto out;
> > > +
> > > + 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;
> > > +
> > > + 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];
> > > + }
> > > +
> > > + dic->rpages = cc->rpages;
> > > + dic->nr_rpages = cc->cluster_size;
> > > + return dic;
> > > +
> > > +out_free:
> > > + f2fs_free_dic(dic);
> > > +out:
> > > + 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;
> > > +                 unlock_page(dic->tpages[i]);
> > > +                 put_page(dic->tpages[i]);
> > > +         }
> > > +         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_set_cluster_uptodate(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);
> > > + }
> > > +}
> > > diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> > > index 58f4bade6c2b..0bfd1b36141b 100644
> > > --- a/fs/f2fs/data.c
> > > +++ b/fs/f2fs/data.c
> > > @@ -41,6 +41,9 @@ 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);
> > >  
> > > @@ -73,19 +76,19 @@ 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;
> > > @@ -94,6 +97,13 @@ 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 && PagePrivate(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);
> > > @@ -110,26 +120,52 @@ static void __read_end_io(struct bio *bio)
> > >   bio_put(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 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);
> > > +}
> > > +
> > > +static void decompress_work(struct bio_post_read_ctx *ctx, bool verity)
> > > +{
> > > + f2fs_decompress_bio(ctx->bio, verity);
> > > +}
> > >  
> > > - bio_post_read_processing(ctx);
> > > +static void verity_work(struct bio_post_read_ctx *ctx)
> > > +{
> > > + fsverity_verify_bio(ctx->bio);
> > >  }
> > >  
> > > -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))
> > > +         decrypt_work(ctx);
> > > +
> > > + if (ctx->enabled_steps & (1 << STEP_DECOMPRESS)) {
> > > +         decompress_work(ctx,
> > > +                 ctx->enabled_steps & (1 << STEP_VERITY));
> > > +         return;
> > > + }
> > > +
> > > + if (ctx->enabled_steps & (1 << STEP_VERITY))
> > > +         verity_work(ctx);
> > >  
> > > - bio_post_read_processing(ctx);
> > > + __read_end_io(ctx->bio, false, 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)
> > > @@ -139,31 +175,18 @@ 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) {
> > > +         INIT_WORK(&ctx->work, f2fs_post_read_work);
> > > +         f2fs_enqueue_post_read_work(ctx->sbi, &ctx->work);
> > > +         return;
> > >   }
> > > + __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)
> > > @@ -178,12 +201,11 @@ 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);
> > > + __read_end_io(bio, false, false);
> > >  }
> > >  
> > >  static void f2fs_write_end_io(struct bio *bio)
> > > @@ -214,6 +236,13 @@ 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)
> > > @@ -358,6 +387,12 @@ static inline void __submit_bio(struct f2fs_sb_info 
> > > *sbi,
> > >   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;
> > > @@ -380,7 +415,6 @@ 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)
> > > @@ -390,10 +424,12 @@ 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))
> > >                   target = fscrypt_pagecache_page(target);
> > > +         if (f2fs_is_compressed_page(target))
> > > +                 target = f2fs_compress_control_page(target);
> > >  
> > >           if (inode && inode == target->mapping->host)
> > >                   return true;
> > > @@ -728,7 +764,12 @@ void f2fs_submit_page_write(struct f2fs_io_info *fio)
> > >  
> > >   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;
> > > @@ -797,7 +838,8 @@ 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;
> > >  
> > > @@ -808,6 +850,7 @@ 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;
> > >   }
> > > @@ -1872,6 +1915,145 @@ static int f2fs_read_single_page(struct inode 
> > > *inode, struct page *page,
> > >   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;
> > > +
> > > + f2fs_bug_on(sbi, dn.data_blkaddr != COMPRESS_ADDR);
> > > +
> > > + 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_set_cluster_uptodate(dic->rpages,
> > > +                                                 cc->cluster_size, true,
> > > +                                                 false);
> > > +                         f2fs_free_dic(dic);
> > > +                         f2fs_put_dnode(&dn);
> > > +                         f2fs_reset_compress_ctx(cc);
> > > +                         *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);
> > > +
> > > + f2fs_reset_compress_ctx(cc);
> > > + *bio_ret = bio;
> > > + return 0;
> > > +
> > > +out_put_dnode:
> > > + f2fs_put_dnode(&dn);
> > > +out:
> > > + f2fs_set_cluster_uptodate(cc->rpages, cc->cluster_size, true, false);
> > > + f2fs_reset_compress_ctx(cc);
> > > + *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.
> > > @@ -1881,7 +2063,7 @@ static int f2fs_read_single_page(struct inode 
> > > *inode, struct page *page,
> > >   * 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)
> > >  {
> > > @@ -1889,6 +2071,19 @@ 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;
> > > @@ -1912,9 +2107,40 @@ 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);
> > > +                         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);
> > > @@ -1922,6 +2148,17 @@ 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);
> > > +         }
> > > +#endif
> > >   }
> > >   BUG_ON(pages && !list_empty(pages));
> > >   if (bio)
> > > @@ -1936,6 +2173,11 @@ 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);
> > > @@ -1954,6 +2196,9 @@ 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;
> > > @@ -1961,22 +2206,23 @@ 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) {
> > > @@ -2136,7 +2382,7 @@ int f2fs_do_write_data_page(struct f2fs_io_info 
> > > *fio)
> > >   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;
> > >  
> > > @@ -2172,7 +2418,7 @@ int f2fs_do_write_data_page(struct f2fs_io_info 
> > > *fio)
> > >  
> > >   fio->version = ni.version;
> > >  
> > > - err = encrypt_one_page(fio);
> > > + err = f2fs_encrypt_one_page(fio);
> > >   if (err)
> > >           goto out_writepage;
> > >  
> > > @@ -2193,7 +2439,7 @@ int f2fs_do_write_data_page(struct f2fs_io_info 
> > > *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,
> > > @@ -2202,7 +2448,7 @@ static int __write_data_page(struct page *page, 
> > > bool *submitted,
> > >   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 = (page->index + 1) << PAGE_SHIFT;
> > >   unsigned nr_pages = DIV_ROUND_UP(i_size, PAGE_SIZE);
> > > @@ -2243,7 +2489,8 @@ 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 (f2fs_compressed_file(inode) ||
> > > +         page->index < end_index || f2fs_verity_in_progress(inode))
> > >           goto write;
> > >  
> > >   /*
> > > @@ -2318,7 +2565,6 @@ static int __write_data_page(struct page *page, 
> > > bool *submitted,
> > >           f2fs_remove_dirty_inode(inode);
> > >           submitted = NULL;
> > >   }
> > > -
> > >   unlock_page(page);
> > >   if (!S_ISDIR(inode->i_mode) && !IS_NOQUOTA(inode) &&
> > >                                   !F2FS_I(inode)->cp_task)
> > > @@ -2331,7 +2577,7 @@ static int __write_data_page(struct page *page, 
> > > bool *submitted,
> > >   }
> > >  
> > >   if (submitted)
> > > -         *submitted = fio.submitted;
> > > +         *submitted = fio.submitted ? 1 : 0;
> > >  
> > >   return 0;
> > >  
> > > @@ -2352,7 +2598,19 @@ static int __write_data_page(struct page *page, 
> > > bool *submitted,
> > >  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 (f2fs_compressed_file(inode)) {
> > > +         if (f2fs_is_compressed_cluster(inode, page->index)) {
> > > +                 redirty_page_for_writepage(wbc, page);
> > > +                 return AOP_WRITEPAGE_ACTIVATE;
> > > +         }
> > > + }
> > > +#endif
> > > +
> > > + return f2fs_write_single_data_page(page, NULL, NULL, NULL,
> > > +                                         wbc, FS_DATA_IO);
> > >  }
> > >  
> > >  /*
> > > @@ -2365,11 +2623,27 @@ 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;
> > > @@ -2379,6 +2653,8 @@ 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);
> > >  
> > > @@ -2408,12 +2684,11 @@ 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)
> > > @@ -2421,7 +2696,51 @@ static int f2fs_write_cache_pages(struct 
> > > address_space *mapping,
> > >  
> > >           for (i = 0; i < nr_pages; i++) {
> > >                   struct page *page = pvec.pages[i];
> > > -                 bool submitted = false;
> > > +                 bool need_readd = false;
> > > +
> > > +readd:
> > > +#ifdef CONFIG_F2FS_FS_COMPRESSION
> > > +                 need_readd = false;
> > > +
> > > +                 if (f2fs_compressed_file(inode)) {
> > > +                         void *fsdata = NULL;
> > > +                         struct page *pagep;
> > > +                         int ret2;
> > > +
> > > +                         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 (f2fs_cluster_is_empty(&cc)) {
> > > +                                 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,
> > > +                                                 true)) {
> > > +                                         retry = 1;
> > > +                                         break;
> > > +                                 }
> > > +                         }
> > > +                 }
> > > +#endif
> > >  
> > >                   /* give a priority to WB_SYNC threads */
> > >                   if (atomic_read(&sbi->wb_sync_req[DATA]) &&
> > > @@ -2431,7 +2750,7 @@ static int f2fs_write_cache_pages(struct 
> > > address_space *mapping,
> > >                   }
> > >  
> > >                   done_index = page->index;
> > > -retry_write:
> > > +
> > >                   lock_page(page);
> > >  
> > >                   if (unlikely(page->mapping != mapping)) {
> > > @@ -2456,45 +2775,64 @@ static int f2fs_write_cache_pages(struct 
> > > address_space *mapping,
> > >                   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)) {
> > > +                         f2fs_compress_ctx_add_page(&cc, page);
> > > +                         continue;
> > > +                 }
> > > +#endif
> > > +                 ret = f2fs_write_single_data_page(page, &submitted,
> > > +                                 &bio, &last_block, wbc, io_type);
> > > +                 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);
> > > -                                         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;
> > > +         /* TODO: error handling */
> > > + }
> > > +#endif
> > > +
> > > + if ((!cycled && !done) || retry) {
> > >           cycled = 1;
> > >           index = 0;
> > >           end = writeback_index - 1;
> > > @@ -2518,6 +2856,8 @@ 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 */
> > > @@ -2660,6 +3000,7 @@ 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);
> > > @@ -2750,6 +3091,24 @@ 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
> > > @@ -2762,6 +3121,8 @@ static int f2fs_write_begin(struct file *file, 
> > > struct address_space *mapping,
> > >           goto fail;
> > >   }
> > >  
> > > + /* TODO: cluster can be compressed due to race with .writepage */
> > > +
> > >   *pagep = page;
> > >  
> > >   err = prepare_write_begin(sbi, page, pos, len,
> > > @@ -2845,6 +3206,16 @@ 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;
> > >  
> > > @@ -3235,6 +3606,15 @@ static int f2fs_swap_activate(struct 
> > > swap_info_struct *sis, struct file *file,
> > >   if (ret)
> > >           return ret;
> > >  
> > > + if (f2fs_compressed_file(inode)) {
> > > +         if (F2FS_I(inode)->i_compressed_blocks)
> > > +                 return -EINVAL;
> > > +
> > > +         F2FS_I(inode)->i_flags &= ~FS_COMPR_FL;
> > > +         clear_inode_flag(inode, FI_COMPRESSED_FILE);
> > > +         stat_dec_compr_inode(inode);
> > > + }
> > > +
> > >   ret = check_swap_activate(file, sis->max);
> > >   if (ret)
> > >           return ret;
> > > @@ -3319,6 +3699,27 @@ 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",
> > > diff --git a/fs/f2fs/debug.c b/fs/f2fs/debug.c
> > > index 5abd1d67d8b2..4f3ef1a892f0 100644
> > > --- a/fs/f2fs/debug.c
> > > +++ b/fs/f2fs/debug.c
> > > @@ -94,6 +94,8 @@ static void update_general_status(struct f2fs_sb_info 
> > > *sbi)
> > >   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;
> > > @@ -315,6 +317,8 @@ static int stat_show(struct seq_file *s, void *v)
> > >                      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",
> > > @@ -491,6 +495,8 @@ int f2fs_build_stats(struct f2fs_sb_info *sbi)
> > >   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);
> > > diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> > > index 8833e9d32f9d..74250d9f5cef 100644
> > > --- a/fs/f2fs/f2fs.h
> > > +++ b/fs/f2fs/f2fs.h
> > > @@ -116,6 +116,8 @@ typedef u32 block_t;  /*
> > >                    */
> > >  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 */
> > > @@ -140,6 +142,12 @@ struct f2fs_mount_info {
> > >   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
> > > @@ -155,6 +163,7 @@ struct f2fs_mount_info {
> > >  #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)
> > > @@ -712,6 +721,12 @@ struct f2fs_inode_info {
> > >   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_compressed_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,
> > > @@ -1056,12 +1071,15 @@ struct f2fs_io_info {
> > >   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 */
> > > + bool compressed;        /* indicate cluster is compressed */
> > > + 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 */
> > > @@ -1169,6 +1187,18 @@ enum fsync_mode {
> > >   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))
> > > @@ -1176,6 +1206,74 @@ enum fsync_mode {
> > >  #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 */
> > > + unsigned int 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 {
> > > + 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 */
> > > + u32 magic;                      /* magic number to indicate page is 
> > > compressed */

Should be first.

> > > +};
> > > +
> > > +/* decompress io context for read IO path */
> > > +struct decompress_io_ctx {
> > > + struct inode *inode;            /* inode the context belong to */
> > > + unsigned int 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 */
> > >   struct proc_dir_entry *s_proc;          /* proc entry */
> > > @@ -1326,6 +1424,8 @@ struct f2fs_sb_info {
> > >   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 aw_cnt;                        /* # of atomic writes */
> > >   atomic_t vw_cnt;                        /* # of volatile writes */
> > >   atomic_t max_aw_cnt;                    /* max # of atomic writes */
> > > @@ -1364,6 +1464,8 @@ struct f2fs_sb_info {
> > >  
> > >   /* 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 {
> > > @@ -2377,11 +2479,13 @@ static inline void f2fs_change_bit(unsigned int 
> > > nr, char *addr)
> > >  /*
> > >   * 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 */
> > > @@ -2390,7 +2494,7 @@ static inline void f2fs_change_bit(unsigned int nr, 
> > > char *addr)
> > >  /* 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 | \
> > > @@ -2442,6 +2546,8 @@ enum {
> > >   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,
> > > @@ -2458,6 +2564,7 @@ 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);
> > >   }
> > >  }
> > > @@ -2613,16 +2720,39 @@ static inline int f2fs_has_inline_xattr(struct 
> > > inode *inode)
> > >   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 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;
> > > +}
> > > +
> > >  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)
> > > @@ -2655,6 +2785,11 @@ 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)
> > >  {
> > >   return is_inode_flag_set(inode, FI_PIN_FILE);
> > > @@ -2782,7 +2917,8 @@ static inline bool f2fs_may_extent_tree(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;
> > >  
> > >   /*
> > > @@ -2896,7 +3032,8 @@ static inline void verify_blkaddr(struct 
> > > f2fs_sb_info *sbi,
> > >  
> > >  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;
> > >  }
> > > @@ -3198,10 +3335,10 @@ void f2fs_destroy_checkpoint_caches(void);
> > >  /*
> > >   * data.c
> > >   */
> > > -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,
> > > @@ -3222,6 +3359,9 @@ int f2fs_reserve_new_block(struct dnode_of_data 
> > > *dn);
> > >  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);
> > > @@ -3235,8 +3375,13 @@ int f2fs_map_blocks(struct inode *inode, struct 
> > > f2fs_map_blocks *map,
> > >                   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);
> > >  void f2fs_invalidate_page(struct page *page, unsigned int offset,
> > >                   unsigned int length);
> > >  int f2fs_release_page(struct page *page, gfp_t wait);
> > > @@ -3246,6 +3391,10 @@ int f2fs_migrate_page(struct address_space 
> > > *mapping, struct page *newpage,
> > >  #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
> > > @@ -3292,6 +3441,7 @@ struct f2fs_stat_info {
> > >   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;
> > > @@ -3362,6 +3512,20 @@ static inline struct f2fs_stat_info 
> > > *F2FS_STAT(struct f2fs_sb_info *sbi)
> > >           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)                \
> > > @@ -3456,6 +3620,10 @@ void f2fs_destroy_root_stats(void);
> > >  #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)                     do { } while (0)
> > > +#define stat_sub_compr_blocks(inode)                     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)
> > > @@ -3595,8 +3763,57 @@ static inline void f2fs_set_encrypted_inode(struct 
> > > inode *inode)
> > >   */
> > >  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);
> > > +void f2fs_reset_compress_ctx(struct compress_ctx *cc);
> > > +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, bool written);
> > > +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_set_cluster_uptodate(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
> > >  
> > >  #define F2FS_FEATURE_FUNCS(name, flagname) \
> > >  static inline int f2fs_sb_has_##name(struct f2fs_sb_info *sbi) \
> > > @@ -3616,6 +3833,7 @@ F2FS_FEATURE_FUNCS(lost_found, LOST_FOUND);
> > >  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,
> > > @@ -3697,6 +3915,15 @@ static inline bool f2fs_may_encrypt(struct inode 
> > > *inode)
> > >  #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 int block_unaligned_IO(struct inode *inode,
> > >                           struct kiocb *iocb, struct iov_iter *iter)
> > >  {
> > > @@ -3728,6 +3955,8 @@ static inline bool f2fs_force_buffered_io(struct 
> > > inode *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
> > >    * all IOs can be serialized by log-structured write.
> > > diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
> > > index a7d855efc294..15a7c5f1bc9f 100644
> > > --- a/fs/f2fs/file.c
> > > +++ b/fs/f2fs/file.c
> > > @@ -51,7 +51,8 @@ static vm_fault_t f2fs_vm_page_mkwrite(struct vm_fault 
> > > *vmf)
> > >   struct inode *inode = file_inode(vmf->vma->vm_file);
> > >   struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
> > >   struct dnode_of_data dn = { .node_changed = false };
> > > - int err;
> > > + bool need_alloc = true;
> > > + int err = 0;
> > >  
> > >   if (unlikely(f2fs_cp_error(sbi))) {
> > >           err = -EIO;
> > > @@ -63,6 +64,20 @@ static vm_fault_t f2fs_vm_page_mkwrite(struct vm_fault 
> > > *vmf)
> > >           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) {
> > > +                 f2fs_bug_on(sbi, ret == CLUSTER_HAS_SPACE);
> > > +                 need_alloc = false;
> > > +         }
> > > + }
> > > +#endif
> > > +
> > >   sb_start_pagefault(inode->i_sb);
> > >  
> > >   f2fs_bug_on(sbi, f2fs_has_inline_data(inode));
> > > @@ -78,15 +93,17 @@ static vm_fault_t f2fs_vm_page_mkwrite(struct 
> > > vm_fault *vmf)
> > >           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 */
> > > @@ -485,6 +502,9 @@ static int f2fs_file_mmap(struct file *file, struct 
> > > vm_area_struct *vma)
> > >   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)
> > > @@ -492,6 +512,7 @@ static int f2fs_file_mmap(struct file *file, struct 
> > > vm_area_struct *vma)
> > >  
> > >   file_accessed(file);
> > >   vma->vm_ops = &f2fs_file_vm_ops;
> > > + set_inode_flag(inode, FI_MMAP_FILE);
> > >   return 0;
> > >  }
> > >  
> > > @@ -518,6 +539,9 @@ void f2fs_truncate_data_blocks_range(struct 
> > > dnode_of_data *dn, int count)
> > >   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);
> > > @@ -525,26 +549,51 @@ void f2fs_truncate_data_blocks_range(struct 
> > > dnode_of_data *dn, int count)
> > >   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) {
> > > +                         int compr_blocks = cluster_size - valid_blocks;
> > > +
> > > +                         stat_sub_compr_blocks(dn->inode, compr_blocks);
> > > +                         F2FS_I(dn->inode)->i_compressed_blocks -=
> > > +                                                         compr_blocks;
> > > +                 }
> > > +                 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) {
> > > +         int compr_blocks = cluster_size - valid_blocks;
> > > +
> > > +         stat_sub_compr_blocks(dn->inode, compr_blocks);
> > > +         F2FS_I(dn->inode)->i_compressed_blocks -= compr_blocks;
> > > + }
> > > +
> > >   if (nr_free) {
> > >           pgoff_t fofs;
> > >           /*
> > > @@ -587,6 +636,9 @@ static int truncate_partial_data_page(struct inode 
> > > *inode, u64 from,
> > >           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);
> > > @@ -602,7 +654,7 @@ static int truncate_partial_data_page(struct inode 
> > > *inode, u64 from,
> > >   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;
> > > @@ -667,6 +719,24 @@ int f2fs_truncate_blocks(struct inode *inode, u64 
> > > from, bool lock)
> > >   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_size = PAGE_SIZE <<
> > > +                                 F2FS_I(inode)->i_log_cluster_size;
> > > +
> > > +         free_from = roundup(from, cluster_size);
> > > + }
> > > +
> > > + return do_truncate_blocks(inode, free_from, lock);
> > > +}
> > > +
> > >  int f2fs_truncate(struct inode *inode)
> > >  {
> > >   int err;
> > > @@ -783,6 +853,10 @@ int f2fs_setattr(struct dentry *dentry, struct iattr 
> > > *attr)
> > >   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)
> > >           return err;
> > > @@ -1023,8 +1097,8 @@ static int __read_out_blkaddrs(struct inode *inode, 
> > > block_t *blkaddr,
> > >   } 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;
> > > @@ -1615,6 +1689,8 @@ static long f2fs_fallocate(struct file *file, int 
> > > mode,
> > >           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))
> > > @@ -1624,6 +1700,11 @@ static long f2fs_fallocate(struct file *file, int 
> > > mode,
> > >           (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 |
> > >                   FALLOC_FL_COLLAPSE_RANGE | FALLOC_FL_ZERO_RANGE |
> > >                   FALLOC_FL_INSERT_RANGE))
> > > @@ -1713,7 +1794,42 @@ static int f2fs_setflags_common(struct inode 
> > > *inode, u32 iflags, u32 mask)
> > >                   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);
> > > +                 set_inode_flag(inode, FI_COMPRESSED_FILE);
> > > +                 stat_inc_compr_inode(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);
> > > @@ -1739,11 +1855,13 @@ static const struct {
> > >   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 },
> > > @@ -1751,11 +1869,13 @@ static const struct {
> > >  };
> > >  
> > >  #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 |     \
> > > @@ -1766,11 +1886,13 @@ static const struct {
> > >           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)
> > > @@ -1891,6 +2013,12 @@ static int f2fs_ioc_start_atomic_write(struct file 
> > > *filp)
> > >  
> > >   inode_lock(inode);
> > >  
> > > + if (f2fs_compressed_file(inode) && !fi->i_compressed_blocks) {
> > > +         fi->i_flags &= ~F2FS_COMPR_FL;
> > > +         clear_inode_flag(inode, FI_COMPRESSED_FILE);
> > > +         stat_dec_compr_inode(inode);
> > > + }
> > > +
> > >   if (f2fs_is_atomic_file(inode)) {
> > >           if (is_inode_flag_set(inode, FI_ATOMIC_REVOKE_REQUEST))
> > >                   ret = -EINVAL;
> > > @@ -3091,6 +3219,17 @@ static int f2fs_ioc_set_pin_file(struct file 
> > > *filp, unsigned long arg)
> > >           ret = -EAGAIN;
> > >           goto out;
> > >   }
> > > +
> > > + if (f2fs_compressed_file(inode)) {
> > > +         if (F2FS_I(inode)->i_compressed_blocks) {
> > > +                 ret = -EOPNOTSUPP;
> > > +                 goto out;
> > > +         }
> > > +         F2FS_I(inode)->i_flags &= ~F2FS_COMPR_FL;
> > > +         clear_inode_flag(inode, FI_COMPRESSED_FILE);
> > > +         stat_dec_compr_inode(inode);
> > > + }
> > > +
> > >   ret = f2fs_convert_inline_inode(inode);
> > >   if (ret)
> > >           goto out;
> > > @@ -3343,6 +3482,17 @@ long f2fs_ioctl(struct file *filp, unsigned int 
> > > cmd, unsigned long arg)
> > >   }
> > >  }
> > >  
> > > +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;
> > > @@ -3354,6 +3504,9 @@ static ssize_t f2fs_file_write_iter(struct kiocb 
> > > *iocb, struct iov_iter *from)
> > >           goto out;
> > >   }
> > >  
> > > + if (!f2fs_is_compress_backend_ready(inode))
> > > +         return -EOPNOTSUPP;
> > > +
> > >   if (iocb->ki_flags & IOCB_NOWAIT) {
> > >           if (!inode_trylock(inode)) {
> > >                   ret = -EAGAIN;
> > > @@ -3467,7 +3620,7 @@ long f2fs_compat_ioctl(struct file *file, unsigned 
> > > int cmd, unsigned long arg)
> > >  
> > >  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,
> > > diff --git a/fs/f2fs/inode.c b/fs/f2fs/inode.c
> > > index 502bd491336a..7a85060adad5 100644
> > > --- a/fs/f2fs/inode.c
> > > +++ b/fs/f2fs/inode.c
> > > @@ -200,6 +200,7 @@ static bool sanity_check_inode(struct inode *inode, 
> > > struct page *node_page)
> > >  {
> > >   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);
> > > @@ -286,6 +287,19 @@ static bool sanity_check_inode(struct inode *inode, 
> > > struct page *node_page)
> > >           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_compressed_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;
> > >  }
> > >  
> > > @@ -407,6 +421,20 @@ static int do_read_inode(struct inode *inode)
> > >           fi->i_crtime.tv_nsec = le32_to_cpu(ri->i_crtime_nsec);
> > >   }
> > >  
> > > + if (f2fs_has_extra_attr(inode) && f2fs_sb_has_compression(sbi)) {
> > > +         if (F2FS_FITS_IN_INODE(ri, fi->i_extra_isize,
> > > +                                 i_log_cluster_size)) {
> > > +                 fi->i_compressed_blocks =
> > > +                                 le64_to_cpu(ri->i_compressed_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;
> > > +         }
> > > +
> > > +         if ((fi->i_flags & F2FS_COMPR_FL) && f2fs_may_compress(inode))
> > > +                 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;
> > > @@ -416,6 +444,8 @@ static int do_read_inode(struct inode *inode)
> > >   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_compressed_blocks);
> > >  
> > >   return 0;
> > >  }
> > > @@ -569,6 +599,17 @@ void f2fs_update_inode(struct inode *inode, struct 
> > > page *node_page)
> > >                   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_compressed_blocks =
> > > +                         cpu_to_le64(F2FS_I(inode)->i_compressed_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);
> > > @@ -711,6 +752,8 @@ void f2fs_evict_inode(struct inode *inode)
> > >   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_compressed_blocks);
> > >  
> > >   if (likely(!f2fs_cp_error(sbi) &&
> > >                           !is_sbi_flag_set(sbi, SBI_CP_DISABLED)))
> > > diff --git a/fs/f2fs/namei.c b/fs/f2fs/namei.c
> > > index d8ca896e109b..5490348bcc6a 100644
> > > --- a/fs/f2fs/namei.c
> > > +++ b/fs/f2fs/namei.c
> > > @@ -119,6 +119,17 @@ static struct inode *f2fs_new_inode(struct inode 
> > > *dir, umode_t mode)
> > >   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_I(inode)->i_flags |= F2FS_COMPR_FL;
> > > +                 set_inode_flag(inode, FI_COMPRESSED_FILE);
> > > +                 stat_inc_compr_inode(inode);

Should remove.

> > > +         }
> > > + }
> > > +
> > >   f2fs_set_inode_flags(inode);
> > >  
> > >   trace_f2fs_new_inode(inode, 0);
> > > @@ -149,6 +160,9 @@ static inline int is_extension_exist(const unsigned 
> > > char *s, const char *sub)
> > >   size_t sublen = strlen(sub);
> > >   int i;
> > >  
> > > + if (sublen == 1 && *sub == '*')
> > > +         return 1;
> > > +
> > >   /*
> > >    * filename format of multimedia file should be defined as:
> > >    * "filename + '.' + extension + (optional: '.' + temp extension)".
> > > @@ -262,6 +276,48 @@ int f2fs_update_extension_list(struct f2fs_sb_info 
> > > *sbi, const char *name,
> > >   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;
> > > +
> > > +         F2FS_I(inode)->i_flags |= F2FS_COMPR_FL;
> > > +         set_compress_context(inode);
> > > +         set_inode_flag(inode, FI_COMPRESSED_FILE);
> > > +         stat_inc_compr_inode(inode);

Should remove.

> > > +         return;
> > > + }
> > > +}
> > > +
> > >  static int f2fs_create(struct inode *dir, struct dentry *dentry, umode_t 
> > > mode,
> > >                                           bool excl)
> > >  {
> > > @@ -286,6 +342,8 @@ static int f2fs_create(struct inode *dir, struct 
> > > dentry *dentry, umode_t mode,
> > >   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;
> > >   inode->i_mapping->a_ops = &f2fs_dblock_aops;
> > > @@ -297,6 +355,7 @@ static int f2fs_create(struct inode *dir, struct 
> > > dentry *dentry, umode_t mode,
> > >           goto out;
> > >   f2fs_unlock_op(sbi);
> > >  
> > > + stat_inc_compr_inode(inode);
> > >   f2fs_alloc_nid_done(sbi, ino);
> > >  
> > >   d_instantiate_new(dentry, inode);
> > > diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> > > index 8c96d6008e20..8b977bbd6822 100644
> > > --- a/fs/f2fs/segment.c
> > > +++ b/fs/f2fs/segment.c
> > > @@ -2215,7 +2215,7 @@ void f2fs_invalidate_blocks(struct f2fs_sb_info 
> > > *sbi, block_t addr)
> > >   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);
> > > @@ -3022,7 +3022,8 @@ static int __get_segment_type_6(struct f2fs_io_info 
> > > *fio)
> > >   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) ||
> > > diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h
> > > index a95467b202ea..a1b3951367cd 100644
> > > --- a/fs/f2fs/segment.h
> > > +++ b/fs/f2fs/segment.h
> > > @@ -200,18 +200,6 @@ struct segment_allocation {
> > >   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 {
> > > diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
> > > index b72d071aedd8..a543ee6b898c 100644
> > > --- a/fs/f2fs/super.c
> > > +++ b/fs/f2fs/super.c
> > > @@ -141,6 +141,9 @@ enum {
> > >   Opt_checkpoint_disable_cap,
> > >   Opt_checkpoint_disable_cap_perc,
> > >   Opt_checkpoint_enable,
> > > + Opt_compress_algorithm,
> > > + Opt_compress_log_size,
> > > + Opt_compress_extension,
> > >   Opt_err,
> > >  };
> > >  
> > > @@ -203,6 +206,9 @@ static match_table_t f2fs_tokens = {
> > >   {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},
> > >  };
> > >  
> > > @@ -391,8 +397,9 @@ static int parse_options(struct super_block *sb, char 
> > > *options)
> > >  {
> > >   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
> > > @@ -810,6 +817,66 @@ static int parse_options(struct super_block *sb, 
> > > char *options)
> > >           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);
> > > @@ -1125,6 +1192,8 @@ static void f2fs_put_super(struct super_block *sb)
> > >   f2fs_destroy_node_manager(sbi);
> > >   f2fs_destroy_segment_manager(sbi);
> > >  
> > > + f2fs_destroy_post_read_wq(sbi);
> > > +
> > >   kfree(sbi->ckpt);
> > >  
> > >   f2fs_unregister_sysfs(sbi);
> > > @@ -1332,6 +1401,35 @@ static inline void f2fs_show_quota_options(struct 
> > > seq_file *seq,
> > >  #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);
> > > @@ -1454,6 +1552,8 @@ static int f2fs_show_options(struct seq_file *seq, 
> > > struct dentry *root)
> > >           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;
> > >  }
> > >  
> > > @@ -1468,6 +1568,9 @@ static void default_options(struct f2fs_sb_info 
> > > *sbi)
> > >   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);
> > > @@ -3397,6 +3500,12 @@ static int f2fs_fill_super(struct super_block *sb, 
> > > void *data, int silent)
> > >           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,
> > > @@ -3618,6 +3727,7 @@ static int f2fs_fill_super(struct super_block *sb, 
> > > void *data, int silent)
> > >   f2fs_destroy_node_manager(sbi);
> > >  free_sm:
> > >   f2fs_destroy_segment_manager(sbi);
> > > + f2fs_destroy_post_read_wq(sbi);
> > >  free_devices:
> > >   destroy_device_list(sbi);
> > >   kfree(sbi->ckpt);
> > > diff --git a/fs/f2fs/sysfs.c b/fs/f2fs/sysfs.c
> > > index f164959e4224..612a2b16d55c 100644
> > > --- a/fs/f2fs/sysfs.c
> > > +++ b/fs/f2fs/sysfs.c
> > > @@ -154,6 +154,9 @@ static ssize_t features_show(struct f2fs_attr *a,
> > >   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");
> > > @@ -389,6 +392,7 @@ enum feat_id {
> > >   FEAT_VERITY,
> > >   FEAT_SB_CHECKSUM,
> > >   FEAT_CASEFOLD,
> > > + FEAT_COMPRESSION,
> > >  };
> > >  
> > >  static ssize_t f2fs_feature_show(struct f2fs_attr *a,
> > > @@ -408,6 +412,7 @@ 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;
> > > @@ -502,6 +507,7 @@ F2FS_FEATURE_RO_ATTR(verity, FEAT_VERITY);
> > >  #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[] = {
> > > @@ -571,6 +577,7 @@ static struct attribute *f2fs_feat_attrs[] = {
> > >  #endif
> > >   ATTR_LIST(sb_checksum),
> > >   ATTR_LIST(casefold),
> > > + ATTR_LIST(compression),
> > >   NULL,
> > >  };
> > >  ATTRIBUTE_GROUPS(f2fs_feat);
> > > diff --git a/include/linux/f2fs_fs.h b/include/linux/f2fs_fs.h
> > > index 284738996028..cc203883b31d 100644
> > > --- a/include/linux/f2fs_fs.h
> > > +++ b/include/linux/f2fs_fs.h
> > > @@ -21,8 +21,15 @@
> > >  #define F2FS_EXTENSION_LEN               8       /* max size of 
> > > extension */
> > >  #define F2FS_BLK_ALIGN(x)        (((x) + F2FS_BLKSIZE - 1) >> 
> > > F2FS_BLKSIZE_BITS)
> > >  
> > > +#define CLUSTER_IS_FULL                  1
> > > +#define  CLUSTER_HAS_SPACE               2
> > > +
> > > +#define COMPRESSED_CLUSTER               1
> > > +#define NORMAL_CLUSTER                   2
> > 
> > I removed the above defs.
> > 
> > > +
> > >  #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)
> > > @@ -271,6 +278,10 @@ struct f2fs_inode {
> > >                   __le32 i_inode_checksum;/* inode meta checksum */
> > >                   __le64 i_crtime;        /* creation time */
> > >                   __le32 i_crtime_nsec;   /* creation time in nano scale 
> > > */
> > > +                 __le64 i_compressed_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 */
> > > diff --git a/include/trace/events/f2fs.h b/include/trace/events/f2fs.h
> > > index 1796ff99c3e9..cb51ea00dbc7 100644
> > > --- a/include/trace/events/f2fs.h
> > > +++ b/include/trace/events/f2fs.h
> > > @@ -148,6 +148,11 @@ TRACE_DEFINE_ENUM(CP_TRIMMED);
> > >           { 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;
> > >  struct extent_info;
> > > @@ -1710,6 +1715,100 @@ TRACE_EVENT(f2fs_shutdown,
> > >           __entry->ret)
> > >  );
> > >  
> > > +DECLARE_EVENT_CLASS(f2fs_zip_start,
> > > +
> > > + TP_PROTO(struct inode *inode, unsigned int 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(unsigned int, 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:%u, "
> > > +         "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, unsigned int 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(unsigned int, 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:%u, "
> > > +         "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, unsigned int 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, unsigned int 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, unsigned int 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, unsigned int cluster_idx,
> > > +                 unsigned int compressed_size, int ret),
> > > +
> > > + TP_ARGS(inode, cluster_idx, compressed_size, ret)
> > > +);
> > > +
> > >  #endif /* _TRACE_F2FS_H */
> > >  
> > >   /* This part must be outside protection */
> > > -- 
> > > 2.18.0.rc1
> > 
> > 
> > _______________________________________________
> > Linux-f2fs-devel mailing list
> > Linux-f2fs-devel@lists.sourceforge.net
> > https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
> 
> 
> _______________________________________________
> Linux-f2fs-devel mailing list
> Linux-f2fs-devel@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel


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