[f2fs-dev] 答复: [PATCH v3] f2fs: compress: add nocompress extensions support

[<changfengnan@vivo.com>]

I think below explanation is clear enough, what do you think?

" After add nocompress_extension, the priority should be:
dir_flag < comp_extention,nocompress_extension <  comp_file_flag,
no_comp_file_flag.

For example:
1.If dir is set compress, the default file and compress_extension specified
file will compress, and nocompress_extension specified file will nocompress.
2.If dir is set not compress, the default file and nocompress_extension
specified file will not compress, but compress_extension specified file will
compress.
3.We can change compress attribute regardless of the file in which type of
dir and specified or not."

-----邮件原件-----
发件人: Chao Yu <yuchao0@huawei.com> 
发送时间: 2021年5月14日 15:50
收件人: Fengnan Chang <changfengnan@vivo.com>
抄送: jaegeuk@kernel.org; linux-f2fs-devel@lists.sourceforge.net
主题: Re: [f2fs-dev] [PATCH v3] f2fs: compress: add nocompress extensions
support

On 2021/5/7 11:05, Fengnan Chang wrote:
> When we create a directory with enable compression, all file write 
> into directory will try to compress.But sometimes we may know, new 
> file cannot meet compression ratio requirements.
> We need a nocompress extension to skip those files to avoid 
> unnecessary compress page test.

Could you please elaborate priority of comp_ext, no_comp_ext, dir_flag,
comp_file_flag, no_comp_file_flag here and in f2fs.rst as well?

> 
> Signed-off-by: Fengnan Chang <changfengnan@vivo.com>
> ---
>   Documentation/filesystems/f2fs.rst |  8 +++
>   fs/f2fs/f2fs.h                     |  2 +
>   fs/f2fs/namei.c                    | 18 +++++--
>   fs/f2fs/super.c                    | 79 +++++++++++++++++++++++++++++-
>   4 files changed, 103 insertions(+), 4 deletions(-)
> 
> diff --git a/Documentation/filesystems/f2fs.rst 
> b/Documentation/filesystems/f2fs.rst
> index 63c0c49b726d..f9248a36cd53 100644
> --- a/Documentation/filesystems/f2fs.rst
> +++ b/Documentation/filesystems/f2fs.rst
> @@ -281,6 +281,14 @@ 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.
> +nocompress_extension=%s	   Support adding specified extension, so
that f2fs can disable
> +			 compression on those corresponding files, just
contrary to compression extension.
> +			 If you know exactly which files cannot be
compressed, you can use this.
> +			 The same extension name can't appear in both
compress and nocompress
> +			 extension at the same time.
> +			 If the compress extension specifies all files, the
types specified by the
> +			 nocompress extension will be treated as special
cases and will not be compressed.
> +			 Don't allow use '*' to specifie all file in
nocompress extension.
>   compress_chksum		 Support verifying chksum of raw data in
compressed cluster.
>   compress_mode=%s	 Control file compression mode. This supports "fs"
and "user"
>   			 modes. In "fs" mode (default), f2fs does automatic
compression 
> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h index 
> 87d734f5589d..3d5d28a2568f 100644
> --- a/fs/f2fs/f2fs.h
> +++ b/fs/f2fs/f2fs.h
> @@ -150,8 +150,10 @@ struct f2fs_mount_info {
>   	unsigned char compress_level;		/* compress level */
>   	bool compress_chksum;			/* compressed data chksum */
>   	unsigned char compress_ext_cnt;		/* extension count */
> +	unsigned char nocompress_ext_cnt;		/* nocompress
extension count */
>   	int compress_mode;			/* compression mode */
>   	unsigned char extensions[COMPRESS_EXT_NUM][F2FS_EXTENSION_LEN];	/*
extensions */
> +	unsigned char noextensions[COMPRESS_EXT_NUM][F2FS_EXTENSION_LEN]; /*

> +extensions */
>   };
> 
>   #define F2FS_FEATURE_ENCRYPT		0x0001
> diff --git a/fs/f2fs/namei.c b/fs/f2fs/namei.c index 
> 405d85dbf9f1..84ca322a22ee 100644
> --- a/fs/f2fs/namei.c
> +++ b/fs/f2fs/namei.c
> @@ -279,14 +279,16 @@ 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 (*noext)[F2FS_EXTENSION_LEN] = 
> +F2FS_OPTION(sbi).noextensions;
>   	unsigned char (*ext)[F2FS_EXTENSION_LEN];
> -	unsigned int ext_cnt = F2FS_OPTION(sbi).compress_ext_cnt;
> +	unsigned char ext_cnt = F2FS_OPTION(sbi).compress_ext_cnt;
> +	unsigned char noext_cnt = F2FS_OPTION(sbi).nocompress_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))
> +			!f2fs_may_compress(inode) ||
> +			(!ext_cnt && !noext_cnt))
>   		return;
> 
>   	down_read(&sbi->sb_lock);
> @@ -303,6 +305,16 @@ static void set_compress_inode(struct 
> f2fs_sb_info *sbi, struct inode *inode,
> 
>   	up_read(&sbi->sb_lock);
> 
> +	for (i = 0; i < noext_cnt; i++) {
> +		if (is_extension_exist(name, noext[i])) {
> +			f2fs_disable_compressed_file(inode);
> +			return;
> +		}
> +	}
> +
> +	if (is_inode_flag_set(inode, FI_COMPRESSED_FILE))
> +		return;
> +
>   	ext = F2FS_OPTION(sbi).extensions;
> 
>   	for (i = 0; i < ext_cnt; i++) {
> diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c index 
> 5020152aa8fc..865191339625 100644
> --- a/fs/f2fs/super.c
> +++ b/fs/f2fs/super.c
> @@ -148,6 +148,7 @@ enum {
>   	Opt_compress_algorithm,
>   	Opt_compress_log_size,
>   	Opt_compress_extension,
> +	Opt_nocompress_extension,
>   	Opt_compress_chksum,
>   	Opt_compress_mode,
>   	Opt_atgc,
> @@ -222,6 +223,7 @@ 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_nocompress_extension, "nocompress_extension=%s"},
>   	{Opt_compress_chksum, "compress_chksum"},
>   	{Opt_compress_mode, "compress_mode=%s"},
>   	{Opt_atgc, "atgc"},
> @@ -473,6 +475,43 @@ static int f2fs_set_test_dummy_encryption(struct
super_block *sb,
>   }
> 
>   #ifdef CONFIG_F2FS_FS_COMPRESSION
> +/*
> + * 1. The same extension name cannot not appear in both compress and 
> +non-compress extension
> + * at the same time.
> + * 2. If the compress extension specifies all files, the types 
> +specified by the non-compress
> + * extension will be treated as special cases and will not be compressed.
> + * 3. Don't allow the non-compress extension specifies all files.
> + */
> +static int f2fs_test_compress_extension(struct f2fs_sb_info *sbi) {
> +	unsigned char (*ext)[F2FS_EXTENSION_LEN];
> +	unsigned char (*noext)[F2FS_EXTENSION_LEN];
> +	int ext_cnt, noext_cnt, index = 0, no_index = 0;
> +
> +	ext = F2FS_OPTION(sbi).extensions;
> +	ext_cnt = F2FS_OPTION(sbi).compress_ext_cnt;
> +	noext = F2FS_OPTION(sbi).noextensions;
> +	noext_cnt = F2FS_OPTION(sbi).nocompress_ext_cnt;
> +
> +	if (!ext_cnt || !noext_cnt)

It doesn't cover the case: ext_cnt = 0, and there is "*" in noext[].

Thanks,

> +		return 0;
> +
> +	for (no_index = 0; no_index < noext_cnt; no_index++) {
> +		if (!strcasecmp("*", noext[no_index])) {
> +			f2fs_info(sbi, "Don't allow the non-compress
extension specifies all files");
> +			return -EINVAL;
> +		}
> +		for (index = 0; index < ext_cnt; index++) {
> +			if (!strcasecmp(ext[index], noext[no_index])) {
> +				f2fs_info(sbi, "Don't allow the same
extension %s appear in both compress and non-compress extension",
> +						ext[index]);
> +				return -EINVAL;
> +			}
> +		}
> +	}
> +	return 0;
> +}
> +
>   #ifdef CONFIG_F2FS_FS_LZ4
>   static int f2fs_set_lz4hc_level(struct f2fs_sb_info *sbi, const char
*str)
>   {
> @@ -546,7 +585,8 @@ static int parse_options(struct super_block *sb, char
*options, bool is_remount)
>   	substring_t args[MAX_OPT_ARGS];
>   #ifdef CONFIG_F2FS_FS_COMPRESSION
>   	unsigned char (*ext)[F2FS_EXTENSION_LEN];
> -	int ext_cnt;
> +	unsigned char (*noext)[F2FS_EXTENSION_LEN];
> +	int ext_cnt, noext_cnt;
>   #endif
>   	char *p, *name;
>   	int arg = 0;
> @@ -1049,6 +1089,30 @@ static int parse_options(struct super_block *sb,
char *options, bool is_remount)
>   			F2FS_OPTION(sbi).compress_ext_cnt++;
>   			kfree(name);
>   			break;
> +		case Opt_nocompress_extension:
> +			if (!f2fs_sb_has_compression(sbi)) {
> +				f2fs_info(sbi, "Image doesn't support
compression");
> +				break;
> +			}
> +			name = match_strdup(&args[0]);
> +			if (!name)
> +				return -ENOMEM;
> +
> +			noext = F2FS_OPTION(sbi).noextensions;
> +			noext_cnt = F2FS_OPTION(sbi).nocompress_ext_cnt;
> +
> +			if (strlen(name) >= F2FS_EXTENSION_LEN ||
> +				noext_cnt >= COMPRESS_EXT_NUM) {
> +				f2fs_err(sbi,
> +					"invalid extension length/number");
> +				kfree(name);
> +				return -EINVAL;
> +			}
> +
> +			strcpy(noext[noext_cnt], name);
> +			F2FS_OPTION(sbi).nocompress_ext_cnt++;
> +			kfree(name);
> +			break;
>   		case Opt_compress_chksum:
>   			F2FS_OPTION(sbi).compress_chksum = true;
>   			break;
> @@ -1070,6 +1134,7 @@ static int parse_options(struct super_block *sb,
char *options, bool is_remount)
>   		case Opt_compress_algorithm:
>   		case Opt_compress_log_size:
>   		case Opt_compress_extension:
> +		case Opt_nocompress_extension:
>   		case Opt_compress_chksum:
>   		case Opt_compress_mode:
>   			f2fs_info(sbi, "compression options not supported");
@@ -1122,6 
> +1187,13 @@ static int parse_options(struct super_block *sb, char
*options, bool is_remount)
>   	}
>   #endif
> 
> +#ifdef CONFIG_F2FS_FS_COMPRESSION
> +	if (f2fs_test_compress_extension(sbi)) {
> +		f2fs_err(sbi, "invalid compress or nocompress extension");
> +		return -EINVAL;
> +	}
> +#endif
> +
>   	if (F2FS_IO_SIZE_BITS(sbi) && !f2fs_lfs_mode(sbi)) {
>   		f2fs_err(sbi, "Should set mode=lfs with %uKB-sized IO",
>   			 F2FS_IO_SIZE_KB(sbi));
> @@ -1665,6 +1737,11 @@ static inline void
f2fs_show_compress_options(struct seq_file *seq,
>   			F2FS_OPTION(sbi).extensions[i]);
>   	}
> 
> +	for (i = 0; i < F2FS_OPTION(sbi).nocompress_ext_cnt; i++) {
> +		seq_printf(seq, ",nocompress_extension=%s",
> +			F2FS_OPTION(sbi).noextensions[i]);
> +	}
> +
>   	if (F2FS_OPTION(sbi).compress_chksum)
>   		seq_puts(seq, ",compress_chksum");
> 
> --
> 2.29.0
> 
> 
> 
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> Linux-f2fs-devel@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
> .
> 




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