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Message-ID: <74933d5b-449e-4061-9571-799acbc42b43@kernel.org>
Date: Mon, 19 Feb 2024 14:14:39 +0800
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Subject: Re: [PATCH] f2fs: support compress extension update via sysfs
 interface
Content-Language: en-US
To: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: linux-f2fs-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org,
 Sheng Yong <shengyong@oppo.com>
References: <20240207062546.3083870-1-chao@kernel.org>
 <ZcQbRzyvb8MNeOMB@google.com>
From: Chao Yu <chao@kernel.org>
In-Reply-To: <ZcQbRzyvb8MNeOMB@google.com>
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On 2024/2/8 8:07, Jaegeuk Kim wrote:
> On 02/07, Chao Yu wrote:
>> Introduce /sys/fs/f2fs/<disk>/compress_extension to support
>> adding/deleting compress extension via sysfs interface, in
>> comparison to mount option, it's more easy to use and less
>> authority issue for applications.
>>
>> Usage:
>> - Query: cat /sys/fs/f2fs/<disk>/compress_extension
>> - Add: echo '[c|n]extension' > /sys/fs/f2fs/<disk>/compress_extension
>> - Del: echo '[c|n]!extension' > /sys/fs/f2fs/<disk>/compress_extension
>> - [c] means add/del compress extension
>> - [n] means add/del nocompress extension
>>
>> Signed-off-by: Sheng Yong <shengyong@oppo.com>
>> Signed-off-by: Chao Yu <chao@kernel.org>
>> ---
>>   Documentation/ABI/testing/sysfs-fs-f2fs | 10 ++++
>>   Documentation/filesystems/f2fs.rst      |  6 ++-
>>   fs/f2fs/compress.c                      | 61 +++++++++++++++++++++++
>>   fs/f2fs/f2fs.h                          |  4 +-
>>   fs/f2fs/sysfs.c                         | 65 +++++++++++++++++++++++--
>>   5 files changed, 139 insertions(+), 7 deletions(-)
>>
>> diff --git a/Documentation/ABI/testing/sysfs-fs-f2fs b/Documentation/ABI/testing/sysfs-fs-f2fs
>> index 48c135e24eb5..1f2cc0913e45 100644
>> --- a/Documentation/ABI/testing/sysfs-fs-f2fs
>> +++ b/Documentation/ABI/testing/sysfs-fs-f2fs
>> @@ -762,3 +762,13 @@ Date:		November 2023
>>   Contact:	"Chao Yu" <chao@kernel.org>
>>   Description:	It controls to enable/disable IO aware feature for background discard.
>>   		By default, the value is 1 which indicates IO aware is on.
>> +
>> +What:		/sys/fs/f2fs/<disk>/compress_extension
>> +Date:		October 2023
>> +Contact:	"Chao Yu" <chao@kernel.org>
>> +Description:	Used to control configure [|no]compress_extension list:
>> +		- Query: cat /sys/fs/f2fs/<disk>/compress_extension
>> +		- Add: echo '[c|n]extension' > /sys/fs/f2fs/<disk>/compress_extension
>> +		- Del: echo '[c|n]!extension' > /sys/fs/f2fs/<disk>/compress_extension
>> +		- [c] means add/del compress extension
>> +		- [n] means add/del nocompress extension
>> diff --git a/Documentation/filesystems/f2fs.rst b/Documentation/filesystems/f2fs.rst
>> index 32cbfa864f38..c82a8fd7316b 100644
>> --- a/Documentation/filesystems/f2fs.rst
>> +++ b/Documentation/filesystems/f2fs.rst
>> @@ -821,17 +821,19 @@ Compression implementation
>>     all logical blocks in cluster contain valid data and compress ratio of
>>     cluster data is lower than specified threshold.
>>   
>> -- To enable compression on regular inode, there are four ways:
>> +- To enable compression on regular inode, there are five ways:
>>   
>>     * chattr +c file
>>     * chattr +c dir; touch dir/file
>>     * mount w/ -o compress_extension=ext; touch file.ext
>>     * mount w/ -o compress_extension=*; touch any_file
>> +  * echo '[c]ext' > /sys/fs/f2fs/<disk>/compress_extension; touch file.ext
>>   
>> -- To disable compression on regular inode, there are two ways:
>> +- To disable compression on regular inode, there are three ways:
>>   
>>     * chattr -c file
>>     * mount w/ -o nocompress_extension=ext; touch file.ext
>> +  * echo '[n]ext' > /sys/fs/f2fs/<disk>/compress_extension; touch file.ext
>>   
>>   - Priority in between FS_COMPR_FL, FS_NOCOMP_FS, extensions:
>>   
>> diff --git a/fs/f2fs/compress.c b/fs/f2fs/compress.c
>> index 3dc488ce882b..a5257882c772 100644
>> --- a/fs/f2fs/compress.c
>> +++ b/fs/f2fs/compress.c
>> @@ -20,6 +20,67 @@
>>   #include "segment.h"
>>   #include <trace/events/f2fs.h>
>>   
>> +static int is_compress_extension_exist(struct f2fs_sb_info *sbi,
>> +				unsigned char (*ext)[F2FS_EXTENSION_LEN],
>> +				int ext_cnt, unsigned char *new_ext)
>> +{
>> +	int i;
>> +
>> +	for (i = 0; i < ext_cnt; i++) {
>> +		if (!strcasecmp(new_ext, ext[i]))
>> +			return i;
>> +	}
>> +	return -1;
>> +}
>> +
>> +int f2fs_update_compress_extension(struct f2fs_sb_info *sbi,
>> +				unsigned char *new_ext, bool is_ext, bool set)
>> +{
>> +	unsigned char (*ext)[F2FS_EXTENSION_LEN];
>> +	unsigned char *ext_cnt;
>> +
>> +	if (is_ext) {
>> +		ext = F2FS_OPTION(sbi).extensions;
>> +		ext_cnt = &F2FS_OPTION(sbi).compress_ext_cnt;
>> +	} else {
>> +		ext = F2FS_OPTION(sbi).noextensions;
>> +		ext_cnt = &F2FS_OPTION(sbi).nocompress_ext_cnt;
>> +	}
>> +
>> +	if (set) {
>> +		if (*ext_cnt >= COMPRESS_EXT_NUM)
>> +			return -EINVAL;
>> +
>> +		if (is_compress_extension_exist(sbi,
>> +					F2FS_OPTION(sbi).extensions,
>> +					F2FS_OPTION(sbi).compress_ext_cnt,
>> +					new_ext) >= 0)
>> +			return -EEXIST;
>> +
>> +		if (is_compress_extension_exist(sbi,
>> +					F2FS_OPTION(sbi).noextensions,
>> +					F2FS_OPTION(sbi).nocompress_ext_cnt,
>> +					new_ext) >= 0)
>> +			return -EEXIST;
>> +
>> +		strcpy(ext[*ext_cnt], new_ext);
>> +		(*ext_cnt)++;
>> +	} else {
>> +		int pos = is_compress_extension_exist(sbi, ext,
>> +						*ext_cnt, new_ext);
>> +		if (pos < 0)
>> +			return -ENOENT;
>> +
>> +		if (pos < *ext_cnt - 1)
>> +			memmove(ext + pos, ext + pos + 1,
>> +				F2FS_EXTENSION_LEN * (*ext_cnt - pos - 1));
>> +		memset(ext + *ext_cnt - 1, 0, F2FS_EXTENSION_LEN);
>> +		(*ext_cnt)--;
>> +	}
>> +
>> +	return 0;
>> +}
>> +
>>   static struct kmem_cache *cic_entry_slab;
>>   static struct kmem_cache *dic_entry_slab;
>>   
>> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
>> index c5e7460d1a0a..d44e2c43d8ab 100644
>> --- a/fs/f2fs/f2fs.h
>> +++ b/fs/f2fs/f2fs.h
>> @@ -186,7 +186,7 @@ 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 */
>> +	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 */
>> @@ -4273,6 +4273,8 @@ static inline bool f2fs_post_read_required(struct inode *inode)
>>    * compress.c
>>    */
>>   #ifdef CONFIG_F2FS_FS_COMPRESSION
>> +int f2fs_update_compress_extension(struct f2fs_sb_info *sbi,
>> +				unsigned char *new_ext, bool is_ext, bool set);
>>   bool f2fs_is_compressed_page(struct page *page);
>>   struct page *f2fs_compress_control_page(struct page *page);
>>   int f2fs_prepare_compress_overwrite(struct inode *inode,
>> diff --git a/fs/f2fs/sysfs.c b/fs/f2fs/sysfs.c
>> index a7ec55c7bb20..a8f05a02e202 100644
>> --- a/fs/f2fs/sysfs.c
>> +++ b/fs/f2fs/sysfs.c
>> @@ -39,6 +39,7 @@ enum {
>>   	RESERVED_BLOCKS,	/* struct f2fs_sb_info */
>>   	CPRC_INFO,	/* struct ckpt_req_control */
>>   	ATGC_INFO,	/* struct atgc_management */
>> +	MOUNT_INFO,	/* struct f2fs_mount_info */
>>   };
>>   
>>   static const char *gc_mode_names[MAX_GC_MODE] = {
>> @@ -89,6 +90,8 @@ static unsigned char *__struct_ptr(struct f2fs_sb_info *sbi, int struct_type)
>>   		return (unsigned char *)&sbi->cprc_info;
>>   	else if (struct_type == ATGC_INFO)
>>   		return (unsigned char *)&sbi->am;
>> +	else if (struct_type == MOUNT_INFO)
>> +		return (unsigned char *)&F2FS_OPTION(sbi);
>>   	return NULL;
>>   }
>>   
>> @@ -358,6 +361,25 @@ static ssize_t f2fs_sbi_show(struct f2fs_attr *a,
>>   
>>   	if (!strcmp(a->attr.name, "compr_new_inode"))
>>   		return sysfs_emit(buf, "%u\n", sbi->compr_new_inode);
>> +
>> +	if (!strcmp(a->attr.name, "compress_extension")) {
>> +		int len = 0, i;
>> +
>> +		f2fs_down_read(&sbi->sb_lock);
>> +		len += scnprintf(buf + len, PAGE_SIZE - len,
>> +						"compress extension:\n");
>> +		for (i = 0; i < F2FS_OPTION(sbi).compress_ext_cnt; i++)
>> +			len += scnprintf(buf + len, PAGE_SIZE - len, "%s\n",
>> +					F2FS_OPTION(sbi).extensions[i]);
>> +
>> +		len += scnprintf(buf + len, PAGE_SIZE - len,
>> +						"nocompress extension:\n");
>> +		for (i = 0; i < F2FS_OPTION(sbi).nocompress_ext_cnt; i++)
>> +			len += scnprintf(buf + len, PAGE_SIZE - len, "%s\n",
>> +					F2FS_OPTION(sbi).noextensions[i]);
> 
> I don't think this is acceptable in sysfs.

It looks block layer output similar string:

cat /sys/block/<dev>/queue/scheduler
mq-deadline kyber [bfq] none

Or, can we add extension entries into /sys/fs/f2fs/<dev>/compress_extensions/
directory? like feature entries in /sys/fs/f2fs/<dev>/feature_list/.

e.g.

ls /sys/fs/f2fs/<dev>/compress_extensions/
so dex

Show enable/disable to indicate current extension is in
compress_extension/nocompress_extension array.

cat /sys/fs/f2fs/<dev>/compress_extensions/so
enable

cat /sys/fs/f2fs/<dev>/compress_extensions/dex
disable

Thanks,

> 
>> +		f2fs_up_read(&sbi->sb_lock);
>> +		return len;
>> +	}
>>   #endif
>>   
>>   	if (!strcmp(a->attr.name, "gc_segment_mode"))
>> @@ -446,6 +468,35 @@ static ssize_t __sbi_store(struct f2fs_attr *a,
>>   		return ret ? ret : count;
>>   	}
>>   
>> +#ifdef CONFIG_F2FS_FS_COMPRESSION
>> +	if (!strcmp(a->attr.name, "compress_extension")) {
>> +		char *name = strim((char *)buf);
>> +		bool set = true, cmpr;
>> +
>> +		if (!strncmp(name, "[c]", 3))
>> +			cmpr = true;
>> +		else if (!strncmp(name, "[n]", 3))
>> +			cmpr = false;
>> +		else
>> +			return -EINVAL;
>> +
>> +		name += 3;
>> +
>> +		if (*name == '!') {
>> +			name++;
>> +			set = false;
>> +		}
>> +
>> +		if (!strlen(name) || strlen(name) >= F2FS_EXTENSION_LEN)
>> +			return -EINVAL;
>> +
>> +		f2fs_down_write(&sbi->sb_lock);
>> +		ret = f2fs_update_compress_extension(sbi, name, cmpr, set);
>> +		f2fs_up_write(&sbi->sb_lock);
>> +		return ret ? ret : count;
>> +	}
>> +#endif
>> +
>>   	if (!strcmp(a->attr.name, "ckpt_thread_ioprio")) {
>>   		const char *name = strim((char *)buf);
>>   		struct ckpt_req_control *cprc = &sbi->cprc_info;
>> @@ -785,15 +836,16 @@ static ssize_t f2fs_sbi_store(struct f2fs_attr *a,
>>   			const char *buf, size_t count)
>>   {
>>   	ssize_t ret;
>> -	bool gc_entry = (!strcmp(a->attr.name, "gc_urgent") ||
>> -					a->struct_type == GC_THREAD);
>> +	bool need_lock = (!strcmp(a->attr.name, "gc_urgent") ||
>> +					a->struct_type == GC_THREAD ||
>> +					a->struct_type == MOUNT_INFO);
>>   
>> -	if (gc_entry) {
>> +	if (need_lock) {
>>   		if (!down_read_trylock(&sbi->sb->s_umount))
>>   			return -EAGAIN;
>>   	}
>>   	ret = __sbi_store(a, sbi, buf, count);
>> -	if (gc_entry)
>> +	if (need_lock)
>>   		up_read(&sbi->sb->s_umount);
>>   
>>   	return ret;
>> @@ -942,6 +994,9 @@ static struct f2fs_attr f2fs_attr_##name = __ATTR(name, 0444, name##_show, NULL)
>>   #define ATGC_INFO_RW_ATTR(name, elname)				\
>>   	F2FS_RW_ATTR(ATGC_INFO, atgc_management, name, elname)
>>   
>> +#define MOUNT_INFO_RW_ATTR(name, elname)			\
>> +	F2FS_RW_ATTR(MOUNT_INFO, f2fs_mount_info, name, elname)
>> +
>>   /* GC_THREAD ATTR */
>>   GC_THREAD_RW_ATTR(gc_urgent_sleep_time, urgent_sleep_time);
>>   GC_THREAD_RW_ATTR(gc_min_sleep_time, min_sleep_time);
>> @@ -1008,6 +1063,7 @@ F2FS_SBI_GENERAL_RW_ATTR(compr_saved_block);
>>   F2FS_SBI_GENERAL_RW_ATTR(compr_new_inode);
>>   F2FS_SBI_GENERAL_RW_ATTR(compress_percent);
>>   F2FS_SBI_GENERAL_RW_ATTR(compress_watermark);
>> +MOUNT_INFO_RW_ATTR(compress_extension, extensions);
>>   #endif
>>   /* atomic write */
>>   F2FS_SBI_GENERAL_RO_ATTR(current_atomic_write);
>> @@ -1181,6 +1237,7 @@ static struct attribute *f2fs_attrs[] = {
>>   	ATTR_LIST(compr_new_inode),
>>   	ATTR_LIST(compress_percent),
>>   	ATTR_LIST(compress_watermark),
>> +	ATTR_LIST(compress_extension),
>>   #endif
>>   	/* For ATGC */
>>   	ATTR_LIST(atgc_candidate_ratio),
>> -- 
>> 2.40.1