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Date:   Tue, 17 Nov 2020 09:13:09 -0800
From:   Jaegeuk Kim <jaegeuk@kernel.org>
To:     Daeho Jeong <daeho43@gmail.com>
Cc:     linux-kernel@vger.kernel.org,
        linux-f2fs-devel@lists.sourceforge.net, kernel-team@android.com,
        Daeho Jeong <daehojeong@google.com>
Subject: Re: [PATCH 1/2] f2fs: add disable_auto_compr mount option
Message-ID: <20201117171309.GA1645652@google.com>
References: <20201117040223.858979-1-daeho43@gmail.com>
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On 11/17, Daeho Jeong wrote:
> From: Daeho Jeong <daehojeong@google.com>
> 
> We will add a new disable_auto_compr mount option to turn off the
> automaic compression on the compression enabled file, in order to
> give discretion of choosing the target file and the timing of
> compression to the user.

The aim would be getting compressed inode format but having no compressed
blocks in file contents which will be done by coming ioctls manually by user.

> 
> Signed-off-by: Daeho Jeong <daehojeong@google.com>
> ---
>  Documentation/filesystems/f2fs.rst |  4 ++++
>  fs/f2fs/data.c                     | 10 +++++-----
>  fs/f2fs/f2fs.h                     |  8 ++++++++
>  fs/f2fs/segment.c                  |  2 +-
>  fs/f2fs/super.c                    |  9 +++++++++
>  5 files changed, 27 insertions(+), 6 deletions(-)
> 
> diff --git a/Documentation/filesystems/f2fs.rst b/Documentation/filesystems/f2fs.rst
> index b8ee761c9922..c36ca1e0f7ab 100644
> --- a/Documentation/filesystems/f2fs.rst
> +++ b/Documentation/filesystems/f2fs.rst
> @@ -260,6 +260,10 @@ compress_extension=%s	 Support adding specified extension, so that f2fs can enab
>  			 For other files, we can still enable compression via ioctl.
>  			 Note that, there is one reserved special extension '*', it
>  			 can be set to enable compression for all files.
> +disable_auto_compr       Even if compression feature is enabled, this option can
> +                         disable automaic compression on the compression enabled
> +                         file to give discretion of choosing the target file and
> +                         the timing of compression to the user.
>  inlinecrypt		 When possible, encrypt/decrypt the contents of encrypted
>  			 files using the blk-crypto framework rather than
>  			 filesystem-layer encryption. This allows the use of
> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> index c31ec408bd4f..414c8370ab7e 100644
> --- a/fs/f2fs/data.c
> +++ b/fs/f2fs/data.c
> @@ -2896,7 +2896,7 @@ static int f2fs_write_data_page(struct page *page,
>  	if (unlikely(f2fs_cp_error(F2FS_I_SB(inode))))
>  		goto out;
>  
> -	if (f2fs_compressed_file(inode)) {
> +	if (f2fs_need_compress_write(inode)) {
>  		if (f2fs_is_compressed_cluster(inode, page->index)) {
>  			redirty_page_for_writepage(wbc, page);
>  			return AOP_WRITEPAGE_ACTIVATE;
> @@ -2988,7 +2988,7 @@ static int f2fs_write_cache_pages(struct address_space *mapping,
>  readd:
>  			need_readd = false;
>  #ifdef CONFIG_F2FS_FS_COMPRESSION
> -			if (f2fs_compressed_file(inode)) {
> +			if (f2fs_need_compress_write(inode)) {
>  				ret = f2fs_init_compress_ctx(&cc);
>  				if (ret) {
>  					done = 1;
> @@ -3067,7 +3067,7 @@ static int f2fs_write_cache_pages(struct address_space *mapping,
>  				goto continue_unlock;
>  
>  #ifdef CONFIG_F2FS_FS_COMPRESSION
> -			if (f2fs_compressed_file(inode)) {
> +			if (f2fs_need_compress_write(inode)) {
>  				get_page(page);
>  				f2fs_compress_ctx_add_page(&cc, page);
>  				continue;
> @@ -3120,7 +3120,7 @@ static int f2fs_write_cache_pages(struct address_space *mapping,
>  	}
>  #ifdef CONFIG_F2FS_FS_COMPRESSION
>  	/* flush remained pages in compress cluster */
> -	if (f2fs_compressed_file(inode) && !f2fs_cluster_is_empty(&cc)) {
> +	if (f2fs_need_compress_write(inode) && !f2fs_cluster_is_empty(&cc)) {
>  		ret = f2fs_write_multi_pages(&cc, &submitted, wbc, io_type);
>  		nwritten += submitted;
>  		wbc->nr_to_write -= submitted;
> @@ -3162,7 +3162,7 @@ static inline bool __should_serialize_io(struct inode *inode,
>  	if (IS_NOQUOTA(inode))
>  		return false;
>  
> -	if (f2fs_compressed_file(inode))
> +	if (f2fs_need_compress_write(inode))
>  		return true;
>  	if (wbc->sync_mode != WB_SYNC_ALL)
>  		return true;
> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> index a33c90cf979b..c473c78699bc 100644
> --- a/fs/f2fs/f2fs.h
> +++ b/fs/f2fs/f2fs.h
> @@ -99,6 +99,7 @@ extern const char *f2fs_fault_name[FAULT_MAX];
>  #define F2FS_MOUNT_DISABLE_CHECKPOINT	0x02000000
>  #define F2FS_MOUNT_NORECOVERY		0x04000000
>  #define F2FS_MOUNT_ATGC			0x08000000
> +#define F2FS_MOUNT_DISABLE_AUTO_COMPR	0x10000000
>  
>  #define F2FS_OPTION(sbi)	((sbi)->mount_opt)
>  #define clear_opt(sbi, option)	(F2FS_OPTION(sbi).opt &= ~F2FS_MOUNT_##option)
> @@ -2838,6 +2839,13 @@ static inline int f2fs_compressed_file(struct inode *inode)
>  		is_inode_flag_set(inode, FI_COMPRESSED_FILE);
>  }
>  
> +static inline int f2fs_need_compress_write(struct inode *inode)
> +{
> +	if (test_opt(F2FS_I_SB(inode), DISABLE_AUTO_COMPR))
> +		return 0;
> +	return f2fs_compressed_file(inode);
> +}
> +
>  static inline unsigned int addrs_per_inode(struct inode *inode)
>  {
>  	unsigned int addrs = CUR_ADDRS_PER_INODE(inode) -
> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> index a0d7a7e04bc7..f56a8b6bbee7 100644
> --- a/fs/f2fs/segment.c
> +++ b/fs/f2fs/segment.c
> @@ -3245,7 +3245,7 @@ static int __get_segment_type_6(struct f2fs_io_info *fio)
>  			else
>  				return CURSEG_COLD_DATA;
>  		}
> -		if (file_is_cold(inode) || f2fs_compressed_file(inode))
> +		if (file_is_cold(inode) || f2fs_need_compress_write(inode))
>  			return CURSEG_COLD_DATA;
>  		if (file_is_hot(inode) ||
>  				is_inode_flag_set(inode, FI_HOT_DATA) ||
> diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
> index 5bb523bf32a6..909c1543b282 100644
> --- a/fs/f2fs/super.c
> +++ b/fs/f2fs/super.c
> @@ -146,6 +146,7 @@ enum {
>  	Opt_compress_algorithm,
>  	Opt_compress_log_size,
>  	Opt_compress_extension,
> +	Opt_disable_auto_compr,
>  	Opt_atgc,
>  	Opt_err,
>  };
> @@ -214,6 +215,7 @@ static match_table_t f2fs_tokens = {
>  	{Opt_compress_algorithm, "compress_algorithm=%s"},
>  	{Opt_compress_log_size, "compress_log_size=%u"},
>  	{Opt_compress_extension, "compress_extension=%s"},
> +	{Opt_disable_auto_compr, "disable_auto_compr"},
>  	{Opt_atgc, "atgc"},
>  	{Opt_err, NULL},
>  };
> @@ -934,10 +936,14 @@ static int parse_options(struct super_block *sb, char *options, bool is_remount)
>  			F2FS_OPTION(sbi).compress_ext_cnt++;
>  			kfree(name);
>  			break;
> +		case Opt_disable_auto_compr:
> +			set_opt(sbi, DISABLE_AUTO_COMPR);
> +			break;
>  #else
>  		case Opt_compress_algorithm:
>  		case Opt_compress_log_size:
>  		case Opt_compress_extension:
> +		case Opt_disable_auto_compr:
>  			f2fs_info(sbi, "compression options not supported");
>  			break;
>  #endif
> @@ -1511,6 +1517,9 @@ static inline void f2fs_show_compress_options(struct seq_file *seq,
>  		seq_printf(seq, ",compress_extension=%s",
>  			F2FS_OPTION(sbi).extensions[i]);
>  	}
> +
> +	if (test_opt(sbi, DISABLE_AUTO_COMPR))
> +		seq_puts(seq, ",disable_auto_compr");
>  }
>  
>  static int f2fs_show_options(struct seq_file *seq, struct dentry *root)
> -- 
> 2.29.2.299.gdc1121823c-goog