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Message-ID: <4b4fc477-5bd8-7d78-ea2c-8a14b23c4534@huawei.com>
Date: Fri, 19 Apr 2024 19:20:40 +0800
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Subject: Re: [PATCH -next] erofs: get rid of erofs_fs_context
Content-Language: en-US
To: Christian Brauner <brauner@kernel.org>
CC: <linux-erofs@lists.ozlabs.org>, <xiang@kernel.org>, <chao@kernel.org>,
	<huyue2@coolpad.com>, <jefflexu@linux.alibaba.com>,
	<viro@zeniv.linux.org.uk>, <linux-kernel@vger.kernel.org>,
	<yangerkun@huawei.com>, <houtao1@huawei.com>, Baokun Li
	<libaokun1@huawei.com>
References: <20240419031459.3050864-1-libaokun1@huawei.com>
 <20240419-tundra-komodowaran-5c3758d496e4@brauner>
From: Baokun Li <libaokun1@huawei.com>
In-Reply-To: <20240419-tundra-komodowaran-5c3758d496e4@brauner>
Content-Type: text/plain; charset="UTF-8"; format=flowed
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On 2024/4/19 18:13, Christian Brauner wrote:
> On Fri, Apr 19, 2024 at 11:14:59AM +0800, Baokun Li wrote:
>> Instead of allocating the erofs_sb_info in get_tree() allocate it during
>> init_fs_context() and after this erofs_fs_context is no longer needed,
>> so replace ctx with sbi, no functional changes.
>>
>> Suggested-by: Jingbo Xu <jefflexu@linux.alibaba.com>
>> Signed-off-by: Baokun Li <libaokun1@huawei.com>
>> ---
>> Hi Gao Xiang,
>> Hi Jingbo,
>>
>> I noticed that Christian's original patch has been merged into the next
>> branch, so I'm sending this patch out separately.
> An an accident on my part as I left it in the vfs.fixes branch. I expect
> that the erofs tree will pick it up.

Hi Christian,

Okay, I'll send the full patch.

>> Regards,
>> Baokun
>>
>>   fs/erofs/internal.h |   7 ---
>>   fs/erofs/super.c    | 112 ++++++++++++++++++--------------------------
>>   2 files changed, 46 insertions(+), 73 deletions(-)
>>
>> diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
>> index 116c1d5d1932..53ebba952a2f 100644
>> --- a/fs/erofs/internal.h
>> +++ b/fs/erofs/internal.h
>> @@ -84,13 +84,6 @@ struct erofs_dev_context {
>>   	bool flatdev;
>>   };
>>   
>> -struct erofs_fs_context {
>> -	struct erofs_mount_opts opt;
>> -	struct erofs_dev_context *devs;
>> -	char *fsid;
>> -	char *domain_id;
>> -};
>> -
>>   /* all filesystem-wide lz4 configurations */
>>   struct erofs_sb_lz4_info {
>>   	/* # of pages needed for EROFS lz4 rolling decompression */
>> diff --git a/fs/erofs/super.c b/fs/erofs/super.c
>> index 4fc34b984e51..7172271290b9 100644
>> --- a/fs/erofs/super.c
>> +++ b/fs/erofs/super.c
>> @@ -370,18 +370,18 @@ static int erofs_read_superblock(struct super_block *sb)
>>   	return ret;
>>   }
>>   
>> -static void erofs_default_options(struct erofs_fs_context *ctx)
>> +static void erofs_default_options(struct erofs_sb_info *sbi)
>>   {
>>   #ifdef CONFIG_EROFS_FS_ZIP
>> -	ctx->opt.cache_strategy = EROFS_ZIP_CACHE_READAROUND;
>> -	ctx->opt.max_sync_decompress_pages = 3;
>> -	ctx->opt.sync_decompress = EROFS_SYNC_DECOMPRESS_AUTO;
>> +	sbi->opt.cache_strategy = EROFS_ZIP_CACHE_READAROUND;
>> +	sbi->opt.max_sync_decompress_pages = 3;
>> +	sbi->opt.sync_decompress = EROFS_SYNC_DECOMPRESS_AUTO;
>>   #endif
>>   #ifdef CONFIG_EROFS_FS_XATTR
>> -	set_opt(&ctx->opt, XATTR_USER);
>> +	set_opt(&sbi->opt, XATTR_USER);
>>   #endif
>>   #ifdef CONFIG_EROFS_FS_POSIX_ACL
>> -	set_opt(&ctx->opt, POSIX_ACL);
>> +	set_opt(&sbi->opt, POSIX_ACL);
>>   #endif
>>   }
>>   
>> @@ -426,16 +426,16 @@ static const struct fs_parameter_spec erofs_fs_parameters[] = {
>>   static bool erofs_fc_set_dax_mode(struct fs_context *fc, unsigned int mode)
>>   {
>>   #ifdef CONFIG_FS_DAX
>> -	struct erofs_fs_context *ctx = fc->fs_private;
>> +	struct erofs_sb_info *sbi = fc->s_fs_info;
>>   
>>   	switch (mode) {
>>   	case EROFS_MOUNT_DAX_ALWAYS:
>> -		set_opt(&ctx->opt, DAX_ALWAYS);
>> -		clear_opt(&ctx->opt, DAX_NEVER);
>> +		set_opt(&sbi->opt, DAX_ALWAYS);
>> +		clear_opt(&sbi->opt, DAX_NEVER);
>>   		return true;
>>   	case EROFS_MOUNT_DAX_NEVER:
>> -		set_opt(&ctx->opt, DAX_NEVER);
>> -		clear_opt(&ctx->opt, DAX_ALWAYS);
>> +		set_opt(&sbi->opt, DAX_NEVER);
>> +		clear_opt(&sbi->opt, DAX_ALWAYS);
>>   		return true;
>>   	default:
>>   		DBG_BUGON(1);
>> @@ -450,7 +450,7 @@ static bool erofs_fc_set_dax_mode(struct fs_context *fc, unsigned int mode)
>>   static int erofs_fc_parse_param(struct fs_context *fc,
>>   				struct fs_parameter *param)
>>   {
>> -	struct erofs_fs_context *ctx = fc->fs_private;
>> +	struct erofs_sb_info *sbi = fc->s_fs_info;
>>   	struct fs_parse_result result;
>>   	struct erofs_device_info *dif;
>>   	int opt, ret;
>> @@ -463,9 +463,9 @@ static int erofs_fc_parse_param(struct fs_context *fc,
>>   	case Opt_user_xattr:
>>   #ifdef CONFIG_EROFS_FS_XATTR
>>   		if (result.boolean)
>> -			set_opt(&ctx->opt, XATTR_USER);
>> +			set_opt(&sbi->opt, XATTR_USER);
>>   		else
>> -			clear_opt(&ctx->opt, XATTR_USER);
>> +			clear_opt(&sbi->opt, XATTR_USER);
>>   #else
>>   		errorfc(fc, "{,no}user_xattr options not supported");
>>   #endif
>> @@ -473,16 +473,16 @@ static int erofs_fc_parse_param(struct fs_context *fc,
>>   	case Opt_acl:
>>   #ifdef CONFIG_EROFS_FS_POSIX_ACL
>>   		if (result.boolean)
>> -			set_opt(&ctx->opt, POSIX_ACL);
>> +			set_opt(&sbi->opt, POSIX_ACL);
>>   		else
>> -			clear_opt(&ctx->opt, POSIX_ACL);
>> +			clear_opt(&sbi->opt, POSIX_ACL);
>>   #else
>>   		errorfc(fc, "{,no}acl options not supported");
>>   #endif
>>   		break;
>>   	case Opt_cache_strategy:
>>   #ifdef CONFIG_EROFS_FS_ZIP
>> -		ctx->opt.cache_strategy = result.uint_32;
>> +		sbi->opt.cache_strategy = result.uint_32;
>>   #else
>>   		errorfc(fc, "compression not supported, cache_strategy ignored");
>>   #endif
>> @@ -504,27 +504,27 @@ static int erofs_fc_parse_param(struct fs_context *fc,
>>   			kfree(dif);
>>   			return -ENOMEM;
>>   		}
>> -		down_write(&ctx->devs->rwsem);
>> -		ret = idr_alloc(&ctx->devs->tree, dif, 0, 0, GFP_KERNEL);
>> -		up_write(&ctx->devs->rwsem);
>> +		down_write(&sbi->devs->rwsem);
>> +		ret = idr_alloc(&sbi->devs->tree, dif, 0, 0, GFP_KERNEL);
>> +		up_write(&sbi->devs->rwsem);
>>   		if (ret < 0) {
>>   			kfree(dif->path);
>>   			kfree(dif);
>>   			return ret;
>>   		}
>> -		++ctx->devs->extra_devices;
>> +		++sbi->devs->extra_devices;
>>   		break;
>>   #ifdef CONFIG_EROFS_FS_ONDEMAND
>>   	case Opt_fsid:
>> -		kfree(ctx->fsid);
>> -		ctx->fsid = kstrdup(param->string, GFP_KERNEL);
>> -		if (!ctx->fsid)
>> +		kfree(sbi->fsid);
>> +		sbi->fsid = kstrdup(param->string, GFP_KERNEL);
>> +		if (!sbi->fsid)
>>   			return -ENOMEM;
>>   		break;
>>   	case Opt_domain_id:
>> -		kfree(ctx->domain_id);
>> -		ctx->domain_id = kstrdup(param->string, GFP_KERNEL);
>> -		if (!ctx->domain_id)
>> +		kfree(sbi->domain_id);
>> +		sbi->domain_id = kstrdup(param->string, GFP_KERNEL);
>> +		if (!sbi->domain_id)
>>   			return -ENOMEM;
>>   		break;
>>   #else
>> @@ -582,7 +582,6 @@ static int erofs_fc_fill_super(struct super_block *sb, struct fs_context *fc)
>>   {
>>   	struct inode *inode;
>>   	struct erofs_sb_info *sbi = EROFS_SB(sb);
>> -	struct erofs_fs_context *ctx = fc->fs_private;
>>   	int err;
>>   
>>   	sb->s_magic = EROFS_SUPER_MAGIC;
>> @@ -590,14 +589,6 @@ static int erofs_fc_fill_super(struct super_block *sb, struct fs_context *fc)
>>   	sb->s_maxbytes = MAX_LFS_FILESIZE;
>>   	sb->s_op = &erofs_sops;
>>   
>> -	sb->s_fs_info = sbi;
>> -	sbi->opt = ctx->opt;
>> -	sbi->devs = ctx->devs;
>> -	ctx->devs = NULL;
>> -	ctx->fsid = NULL;
>> -	sbi->domain_id = ctx->domain_id;
>> -	ctx->domain_id = NULL;
>> -
>>   	sbi->blkszbits = PAGE_SHIFT;
>>   	if (erofs_is_fscache_mode(sb)) {
>>   		sb->s_blocksize = PAGE_SIZE;
>> @@ -701,15 +692,8 @@ static int erofs_fc_fill_super(struct super_block *sb, struct fs_context *fc)
>>   
>>   static int erofs_fc_get_tree(struct fs_context *fc)
>>   {
>> -	struct erofs_fs_context *ctx = fc->fs_private;
>> -	struct erofs_sb_info *sbi;
>> -
>> -	sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
>> -	if (!sbi)
>> -		return -ENOMEM;
>> +	struct erofs_sb_info *sbi = fc->s_fs_info;
>>   
>> -	fc->s_fs_info = sbi;
>> -	sbi->fsid = ctx->fsid;
>>   	if (IS_ENABLED(CONFIG_EROFS_FS_ONDEMAND) && sbi->fsid)
>>   		return get_tree_nodev(fc, erofs_fc_fill_super);
>>   
>> @@ -720,19 +704,19 @@ static int erofs_fc_reconfigure(struct fs_context *fc)
>>   {
>>   	struct super_block *sb = fc->root->d_sb;
>>   	struct erofs_sb_info *sbi = EROFS_SB(sb);
>> -	struct erofs_fs_context *ctx = fc->fs_private;
>> +	struct erofs_sb_info *new_sbi = fc->s_fs_info;
>>   
>>   	DBG_BUGON(!sb_rdonly(sb));
>>   
>> -	if (ctx->fsid || ctx->domain_id)
>> +	if (new_sbi->fsid || new_sbi->domain_id)
>>   		erofs_info(sb, "ignoring reconfiguration for fsid|domain_id.");
>>   
>> -	if (test_opt(&ctx->opt, POSIX_ACL))
>> +	if (test_opt(&new_sbi->opt, POSIX_ACL))
>>   		fc->sb_flags |= SB_POSIXACL;
>>   	else
>>   		fc->sb_flags &= ~SB_POSIXACL;
>>   
>> -	sbi->opt = ctx->opt;
>> +	sbi->opt = new_sbi->opt;
>>   
>>   	fc->sb_flags |= SB_RDONLY;
>>   	return 0;
>> @@ -763,16 +747,12 @@ static void erofs_free_dev_context(struct erofs_dev_context *devs)
>>   
>>   static void erofs_fc_free(struct fs_context *fc)
>>   {
>> -	struct erofs_fs_context *ctx = fc->fs_private;
>>   	struct erofs_sb_info *sbi = fc->s_fs_info;
>>   
>> -	erofs_free_dev_context(ctx->devs);
>> -	kfree(ctx->fsid);
>> -	kfree(ctx->domain_id);
>> -	kfree(ctx);
>> -
>> -	if (sbi)
>> -		kfree(sbi);
>> +	erofs_free_dev_context(sbi->devs);
>> +	kfree(sbi->fsid);
>> +	kfree(sbi->domain_id);
>> +	kfree(sbi);
>>   }
>>   
>>   static const struct fs_context_operations erofs_context_ops = {
>> @@ -784,22 +764,22 @@ static const struct fs_context_operations erofs_context_ops = {
>>   
>>   static int erofs_init_fs_context(struct fs_context *fc)
>>   {
>> -	struct erofs_fs_context *ctx;
>> +	struct erofs_sb_info *sbi;
>>   
>> -	ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
>> -	if (!ctx)
>> +	sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
>> +	if (!sbi)
>>   		return -ENOMEM;
>>   
>> -	ctx->devs = kzalloc(sizeof(struct erofs_dev_context), GFP_KERNEL);
>> -	if (!ctx->devs) {
>> -		kfree(ctx);
>> +	sbi->devs = kzalloc(sizeof(struct erofs_dev_context), GFP_KERNEL);
>> +	if (!sbi->devs) {
>> +		kfree(sbi);
>>   		return -ENOMEM;
>>   	}
>> -	fc->fs_private = ctx;
>> +	fc->fs_private = sbi;
> I don't understand how your patch is going to work. fs_private isn't
> transfered by the generic code to sb->s_fs_info. Did you mean
> fc->s_fs_info = sbi?
Yes, it's fc->s_fs_info, my mistake!

The original plan was to split into two patches, getting rid of
erofs_fs_context in the first and fixing the problem in the second.

I wrote the patch yesterday and tested it, but when I sent it out
today after testing it, I noticed that your original patch was
merged in, and then I made a mistake when rebasing on the
new next branch, sorry about that. I'll send out the previous
patch soon.

Thanks for the correction!
>
>>   
>> -	idr_init(&ctx->devs->tree);
>> -	init_rwsem(&ctx->devs->rwsem);
>> -	erofs_default_options(ctx);
>> +	idr_init(&sbi->devs->tree);
>> +	init_rwsem(&sbi->devs->rwsem);
>> +	erofs_default_options(sbi);
>>   	fc->ops = &erofs_context_ops;
>>   	return 0;
>>   }
>> -- 
>> 2.31.1
>>
Thanks again!
-- 
With Best Regards,
Baokun Li