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[PATCH V2 5/5] erofs: support fscache based shared domain

Jia Zhu posted 5 patches 3 years, 7 months ago
There is a newer version of this series
[PATCH V2 5/5] erofs: support fscache based shared domain
Posted by Jia Zhu 3 years, 7 months ago 
Several erofs filesystems can belong to one domain, and data blobs can
be shared among these erofs filesystems of same domain.

Users could specify domain_id mount option to create or join into a domain.

Signed-off-by: Jia Zhu <zhujia.zj@bytedance.com>
---
 fs/erofs/fscache.c  | 73 +++++++++++++++++++++++++++++++++++++++++++++
 fs/erofs/internal.h | 12 ++++++++
 fs/erofs/super.c    | 10 +++++--
 3 files changed, 93 insertions(+), 2 deletions(-)

diff --git a/fs/erofs/fscache.c b/fs/erofs/fscache.c
index 439dd3cc096a..c01845808ede 100644
--- a/fs/erofs/fscache.c
+++ b/fs/erofs/fscache.c
@@ -559,12 +559,27 @@ int erofs_fscache_register_cookie(struct super_block *sb,
 void erofs_fscache_unregister_cookie(struct erofs_fscache **fscache)
 {
 	struct erofs_fscache *ctx = *fscache;
+	struct erofs_domain *domain;
 
 	if (!ctx)
 		return;
+	domain = ctx->domain;
+	if (domain) {
+		mutex_lock(&domain->mutex);
+		/* Cookie is still in use */
+		if (atomic_read(&ctx->anon_inode->i_count) > 1) {
+			iput(ctx->anon_inode);
+			mutex_unlock(&domain->mutex);
+			return;
+		}
+		iput(ctx->anon_inode);
+		kfree(ctx->name);
+		mutex_unlock(&domain->mutex);
+	}
 
 	fscache_unuse_cookie(ctx->cookie, NULL, NULL);
 	fscache_relinquish_cookie(ctx->cookie, false);
+	erofs_fscache_domain_put(domain);
 	ctx->cookie = NULL;
 
 	iput(ctx->inode);
@@ -609,3 +624,61 @@ void erofs_fscache_unregister_fs(struct super_block *sb)
 	sbi->volume = NULL;
 	sbi->domain = NULL;
 }
+
+static int erofs_fscache_domain_init_cookie(struct super_block *sb,
+		struct erofs_fscache **fscache, char *name, bool need_inode)
+{
+	int ret;
+	struct inode *inode;
+	struct erofs_fscache *ctx;
+	struct erofs_sb_info *sbi = EROFS_SB(sb);
+	struct erofs_domain *domain = sbi->domain;
+
+	ret = erofs_fscache_register_cookie(sb, &ctx, name, need_inode);
+	if (ret)
+		return ret;
+
+	ctx->name = kstrdup(name, GFP_KERNEL);
+	if (!ctx->name)
+		return -ENOMEM;
+
+	inode = new_inode(erofs_pseudo_mnt->mnt_sb);
+	if (!inode) {
+		kfree(ctx->name);
+		return -ENOMEM;
+	}
+
+	ctx->domain = domain;
+	ctx->anon_inode = inode;
+	inode->i_private = ctx;
+	erofs_fscache_domain_get(domain);
+	*fscache = ctx;
+	return 0;
+}
+
+int erofs_domain_register_cookie(struct super_block *sb,
+	struct erofs_fscache **fscache, char *name, bool need_inode)
+{
+	int err;
+	struct inode *inode;
+	struct erofs_fscache *ctx;
+	struct erofs_sb_info *sbi = EROFS_SB(sb);
+	struct erofs_domain *domain = sbi->domain;
+	struct super_block *psb = erofs_pseudo_mnt->mnt_sb;
+
+	mutex_lock(&domain->mutex);
+	list_for_each_entry(inode, &psb->s_inodes, i_sb_list) {
+		ctx = inode->i_private;
+		if (!ctx)
+			continue;
+		if (!strcmp(ctx->name, name)) {
+			*fscache = ctx;
+			igrab(inode);
+			mutex_unlock(&domain->mutex);
+			return 0;
+		}
+	}
+	err = erofs_fscache_domain_init_cookie(sb, fscache, name, need_inode);
+	mutex_unlock(&domain->mutex);
+	return err;
+}
diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
index 2790c93ffb83..efa4f4ad77cc 100644
--- a/fs/erofs/internal.h
+++ b/fs/erofs/internal.h
@@ -110,6 +110,9 @@ struct erofs_domain {
 struct erofs_fscache {
 	struct fscache_cookie *cookie;
 	struct inode *inode;
+	struct inode *anon_inode;
+	struct erofs_domain *domain;
+	char *name;
 };
 
 struct erofs_sb_info {
@@ -625,6 +628,9 @@ int erofs_fscache_register_domain(struct super_block *sb);
 int erofs_fscache_register_cookie(struct super_block *sb,
 				  struct erofs_fscache **fscache,
 				  char *name, bool need_inode);
+int erofs_domain_register_cookie(struct super_block *sb,
+				  struct erofs_fscache **fscache,
+				  char *name, bool need_inode);
 void erofs_fscache_unregister_cookie(struct erofs_fscache **fscache);
 
 extern const struct address_space_operations erofs_fscache_access_aops;
@@ -646,6 +652,12 @@ static inline int erofs_fscache_register_cookie(struct super_block *sb,
 {
 	return -EOPNOTSUPP;
 }
+static inline int erofs_domain_register_cookie(struct super_block *sb,
+						struct erofs_fscache **fscache,
+						char *name, bool need_inode)
+{
+	return -EOPNOTSUPP;
+}
 
 static inline void erofs_fscache_unregister_cookie(struct erofs_fscache **fscache)
 {
diff --git a/fs/erofs/super.c b/fs/erofs/super.c
index 667a78f0ee70..11c5ba84567c 100644
--- a/fs/erofs/super.c
+++ b/fs/erofs/super.c
@@ -245,8 +245,12 @@ static int erofs_init_device(struct erofs_buf *buf, struct super_block *sb,
 	}
 
 	if (erofs_is_fscache_mode(sb)) {
-		ret = erofs_fscache_register_cookie(sb, &dif->fscache,
-				dif->path, false);
+		if (sbi->opt.domain_id)
+			ret = erofs_domain_register_cookie(sb, &dif->fscache, dif->path,
+					false);
+		else
+			ret = erofs_fscache_register_cookie(sb, &dif->fscache, dif->path,
+					false);
 		if (ret)
 			return ret;
 	} else {
@@ -726,6 +730,8 @@ static int erofs_fc_fill_super(struct super_block *sb, struct fs_context *fc)
 			err = erofs_fscache_register_domain(sb);
 			if (err)
 				return err;
+			err = erofs_domain_register_cookie(sb, &sbi->s_fscache,
+					sbi->opt.fsid, true);
 		} else {
 			err = erofs_fscache_register_fs(sb);
 			if (err)
-- 
2.20.1
Re: [PATCH V2 5/5] erofs: support fscache based shared domain
Posted by JeffleXu 3 years, 6 months ago 

On 9/2/22 6:53 PM, Jia Zhu wrote:
> Several erofs filesystems can belong to one domain, and data blobs can
> be shared among these erofs filesystems of same domain.
> 
> Users could specify domain_id mount option to create or join into a domain.
> 
> Signed-off-by: Jia Zhu <zhujia.zj@bytedance.com>
> ---
>  fs/erofs/fscache.c  | 73 +++++++++++++++++++++++++++++++++++++++++++++
>  fs/erofs/internal.h | 12 ++++++++
>  fs/erofs/super.c    | 10 +++++--
>  3 files changed, 93 insertions(+), 2 deletions(-)
> 
> diff --git a/fs/erofs/fscache.c b/fs/erofs/fscache.c
> index 439dd3cc096a..c01845808ede 100644
> --- a/fs/erofs/fscache.c
> +++ b/fs/erofs/fscache.c
> @@ -559,12 +559,27 @@ int erofs_fscache_register_cookie(struct super_block *sb,
>  void erofs_fscache_unregister_cookie(struct erofs_fscache **fscache)
>  {
>  	struct erofs_fscache *ctx = *fscache;
> +	struct erofs_domain *domain;
>  
>  	if (!ctx)
>  		return;
> +	domain = ctx->domain;
> +	if (domain) {
> +		mutex_lock(&domain->mutex);
> +		/* Cookie is still in use */
> +		if (atomic_read(&ctx->anon_inode->i_count) > 1) {
> +			iput(ctx->anon_inode);
> +			mutex_unlock(&domain->mutex);
> +			return;
> +		}
> +		iput(ctx->anon_inode);
> +		kfree(ctx->name);
> +		mutex_unlock(&domain->mutex);
> +	}
>  
>  	fscache_unuse_cookie(ctx->cookie, NULL, NULL);
>  	fscache_relinquish_cookie(ctx->cookie, false);
> +	erofs_fscache_domain_put(domain);
>  	ctx->cookie = NULL;
>  
>  	iput(ctx->inode);
> @@ -609,3 +624,61 @@ void erofs_fscache_unregister_fs(struct super_block *sb)
>  	sbi->volume = NULL;
>  	sbi->domain = NULL;
>  }
> +
> +static int erofs_fscache_domain_init_cookie(struct super_block *sb,
> +		struct erofs_fscache **fscache, char *name, bool need_inode)
> +{
> +	int ret;
> +	struct inode *inode;
> +	struct erofs_fscache *ctx;
> +	struct erofs_sb_info *sbi = EROFS_SB(sb);
> +	struct erofs_domain *domain = sbi->domain;
> +
> +	ret = erofs_fscache_register_cookie(sb, &ctx, name, need_inode);
> +	if (ret)
> +		return ret;
> +
> +	ctx->name = kstrdup(name, GFP_KERNEL);
> +	if (!ctx->name)
> +		return -ENOMEM;

Shall we clean up the above registered cookie in the error path?

> +
> +	inode = new_inode(erofs_pseudo_mnt->mnt_sb);
> +	if (!inode) {
> +		kfree(ctx->name);
> +		return -ENOMEM;
> +	}

Ditto.

> +
> +	ctx->domain = domain;
> +	ctx->anon_inode = inode;
> +	inode->i_private = ctx;
> +	erofs_fscache_domain_get(domain);
> +	*fscache = ctx;
> +	return 0;
> +}
> +
> +int erofs_domain_register_cookie(struct super_block *sb,
> +	struct erofs_fscache **fscache, char *name, bool need_inode)
> +{
> +	int err;
> +	struct inode *inode;
> +	struct erofs_fscache *ctx;
> +	struct erofs_sb_info *sbi = EROFS_SB(sb);
> +	struct erofs_domain *domain = sbi->domain;
> +	struct super_block *psb = erofs_pseudo_mnt->mnt_sb;
> +
> +	mutex_lock(&domain->mutex);

What is domain->mutex used for?


> +	list_for_each_entry(inode, &psb->s_inodes, i_sb_list) {
> +		ctx = inode->i_private;
> +		if (!ctx)
> +			continue;
> +		if (!strcmp(ctx->name, name)) {
> +			*fscache = ctx;
> +			igrab(inode);
> +			mutex_unlock(&domain->mutex);
> +			return 0;
> +		}
> +	}
> +	err = erofs_fscache_domain_init_cookie(sb, fscache, name, need_inode);
> +	mutex_unlock(&domain->mutex);
> +	return err;
> +}
> diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
> index 2790c93ffb83..efa4f4ad77cc 100644
> --- a/fs/erofs/internal.h
> +++ b/fs/erofs/internal.h
> @@ -110,6 +110,9 @@ struct erofs_domain {
>  struct erofs_fscache {
>  	struct fscache_cookie *cookie;
>  	struct inode *inode;
> +	struct inode *anon_inode;

Why can't we reuse @inode for anon_inode?


> +	struct erofs_domain *domain;
> +	char *name;
>  };
>  
>  struct erofs_sb_info {
> @@ -625,6 +628,9 @@ int erofs_fscache_register_domain(struct super_block *sb);
>  int erofs_fscache_register_cookie(struct super_block *sb,
>  				  struct erofs_fscache **fscache,
>  				  char *name, bool need_inode);
> +int erofs_domain_register_cookie(struct super_block *sb,
> +				  struct erofs_fscache **fscache,
> +				  char *name, bool need_inode);
>  void erofs_fscache_unregister_cookie(struct erofs_fscache **fscache);
>  
>  extern const struct address_space_operations erofs_fscache_access_aops;
> @@ -646,6 +652,12 @@ static inline int erofs_fscache_register_cookie(struct super_block *sb,
>  {
>  	return -EOPNOTSUPP;
>  }
> +static inline int erofs_domain_register_cookie(struct super_block *sb,
> +						struct erofs_fscache **fscache,
> +						char *name, bool need_inode)
> +{
> +	return -EOPNOTSUPP;
> +}
>  
>  static inline void erofs_fscache_unregister_cookie(struct erofs_fscache **fscache)
>  {
> diff --git a/fs/erofs/super.c b/fs/erofs/super.c
> index 667a78f0ee70..11c5ba84567c 100644
> --- a/fs/erofs/super.c
> +++ b/fs/erofs/super.c
> @@ -245,8 +245,12 @@ static int erofs_init_device(struct erofs_buf *buf, struct super_block *sb,
>  	}
>  
>  	if (erofs_is_fscache_mode(sb)) {
> -		ret = erofs_fscache_register_cookie(sb, &dif->fscache,
> -				dif->path, false);
> +		if (sbi->opt.domain_id)
> +			ret = erofs_domain_register_cookie(sb, &dif->fscache, dif->path,
> +					false);
> +		else
> +			ret = erofs_fscache_register_cookie(sb, &dif->fscache, dif->path,
> +					false);
>  		if (ret)
>  			return ret;
>  	} else {
> @@ -726,6 +730,8 @@ static int erofs_fc_fill_super(struct super_block *sb, struct fs_context *fc)
>  			err = erofs_fscache_register_domain(sb);
>  			if (err)
>  				return err;
> +			err = erofs_domain_register_cookie(sb, &sbi->s_fscache,
> +					sbi->opt.fsid, true);
>  		} else {
>  			err = erofs_fscache_register_fs(sb);
>  			if (err)

-- 
Thanks,
Jingbo
Re: [External] Re: [PATCH V2 5/5] erofs: support fscache based shared domain
Posted by Jia Zhu 3 years, 6 months ago 

在 2022/9/13 14:27, JeffleXu 写道:
> 
> 
> On 9/2/22 6:53 PM, Jia Zhu wrote:
>> Several erofs filesystems can belong to one domain, and data blobs can
>> be shared among these erofs filesystems of same domain.
>>
>> Users could specify domain_id mount option to create or join into a domain.
>>
>> Signed-off-by: Jia Zhu <zhujia.zj@bytedance.com>
>> ---
>>   fs/erofs/fscache.c  | 73 +++++++++++++++++++++++++++++++++++++++++++++
>>   fs/erofs/internal.h | 12 ++++++++
>>   fs/erofs/super.c    | 10 +++++--
>>   3 files changed, 93 insertions(+), 2 deletions(-)
>>
>> diff --git a/fs/erofs/fscache.c b/fs/erofs/fscache.c
>> index 439dd3cc096a..c01845808ede 100644
>> --- a/fs/erofs/fscache.c
>> +++ b/fs/erofs/fscache.c
>> @@ -559,12 +559,27 @@ int erofs_fscache_register_cookie(struct super_block *sb,
>>   void erofs_fscache_unregister_cookie(struct erofs_fscache **fscache)
>>   {
>>   	struct erofs_fscache *ctx = *fscache;
>> +	struct erofs_domain *domain;
>>   
>>   	if (!ctx)
>>   		return;
>> +	domain = ctx->domain;
>> +	if (domain) {
>> +		mutex_lock(&domain->mutex);
>> +		/* Cookie is still in use */
>> +		if (atomic_read(&ctx->anon_inode->i_count) > 1) {
>> +			iput(ctx->anon_inode);
>> +			mutex_unlock(&domain->mutex);
>> +			return;
>> +		}
>> +		iput(ctx->anon_inode);
>> +		kfree(ctx->name);
>> +		mutex_unlock(&domain->mutex);
>> +	}
>>   
>>   	fscache_unuse_cookie(ctx->cookie, NULL, NULL);
>>   	fscache_relinquish_cookie(ctx->cookie, false);
>> +	erofs_fscache_domain_put(domain);
>>   	ctx->cookie = NULL;
>>   
>>   	iput(ctx->inode);
>> @@ -609,3 +624,61 @@ void erofs_fscache_unregister_fs(struct super_block *sb)
>>   	sbi->volume = NULL;
>>   	sbi->domain = NULL;
>>   }
>> +
>> +static int erofs_fscache_domain_init_cookie(struct super_block *sb,
>> +		struct erofs_fscache **fscache, char *name, bool need_inode)
>> +{
>> +	int ret;
>> +	struct inode *inode;
>> +	struct erofs_fscache *ctx;
>> +	struct erofs_sb_info *sbi = EROFS_SB(sb);
>> +	struct erofs_domain *domain = sbi->domain;
>> +
>> +	ret = erofs_fscache_register_cookie(sb, &ctx, name, need_inode);
>> +	if (ret)
>> +		return ret;
>> +
>> +	ctx->name = kstrdup(name, GFP_KERNEL);
>> +	if (!ctx->name)
>> +		return -ENOMEM;
> 
> Shall we clean up the above registered cookie in the error path?
> 
If this step fails, error will be transmitted to vfs_get_tree() and
erofs_kill_sb() will relinquish the cookie.
>> +
>> +	inode = new_inode(erofs_pseudo_mnt->mnt_sb);
>> +	if (!inode) {
>> +		kfree(ctx->name);
>> +		return -ENOMEM;
>> +	}
> 
> Ditto.
> 
>> +
>> +	ctx->domain = domain;
>> +	ctx->anon_inode = inode;
>> +	inode->i_private = ctx;
>> +	erofs_fscache_domain_get(domain);
>> +	*fscache = ctx;
>> +	return 0;
>> +}
>> +
>> +int erofs_domain_register_cookie(struct super_block *sb,
>> +	struct erofs_fscache **fscache, char *name, bool need_inode)
>> +{
>> +	int err;
>> +	struct inode *inode;
>> +	struct erofs_fscache *ctx;
>> +	struct erofs_sb_info *sbi = EROFS_SB(sb);
>> +	struct erofs_domain *domain = sbi->domain;
>> +	struct super_block *psb = erofs_pseudo_mnt->mnt_sb;
>> +
>> +	mutex_lock(&domain->mutex);
> 
> What is domain->mutex used for?
> 
This lock is used to avoid race conditions between cookie's
traverse/del/insert in the inode list.
It seems to be possible to increase the granularity of the lock
after v2's change "Only initialize one pseudo fs to manage anonymous 
inodes(cookies).".
> 
>> +	list_for_each_entry(inode, &psb->s_inodes, i_sb_list) {
>> +		ctx = inode->i_private;
>> +		if (!ctx)
>> +			continue;
>> +		if (!strcmp(ctx->name, name)) {
>> +			*fscache = ctx;
>> +			igrab(inode);
>> +			mutex_unlock(&domain->mutex);
>> +			return 0;
>> +		}
>> +	}
>> +	err = erofs_fscache_domain_init_cookie(sb, fscache, name, need_inode);
>> +	mutex_unlock(&domain->mutex);
>> +	return err;
>> +}
>> diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
>> index 2790c93ffb83..efa4f4ad77cc 100644
>> --- a/fs/erofs/internal.h
>> +++ b/fs/erofs/internal.h
>> @@ -110,6 +110,9 @@ struct erofs_domain {
>>   struct erofs_fscache {
>>   	struct fscache_cookie *cookie;
>>   	struct inode *inode;
>> +	struct inode *anon_inode;
> 
> Why can't we reuse @inode for anon_inode?
> 
We use pseudo sb's anonymous inodes list to manage the cookie.
Wouldn't it be a bit of messy if reuses erofs meta inode?
> 
>> +	struct erofs_domain *domain;
>> +	char *name;
>>   };
>>   
>>   struct erofs_sb_info {
>> @@ -625,6 +628,9 @@ int erofs_fscache_register_domain(struct super_block *sb);
>>   int erofs_fscache_register_cookie(struct super_block *sb,
>>   				  struct erofs_fscache **fscache,
>>   				  char *name, bool need_inode);
>> +int erofs_domain_register_cookie(struct super_block *sb,
>> +				  struct erofs_fscache **fscache,
>> +				  char *name, bool need_inode);
>>   void erofs_fscache_unregister_cookie(struct erofs_fscache **fscache);
>>   
>>   extern const struct address_space_operations erofs_fscache_access_aops;
>> @@ -646,6 +652,12 @@ static inline int erofs_fscache_register_cookie(struct super_block *sb,
>>   {
>>   	return -EOPNOTSUPP;
>>   }
>> +static inline int erofs_domain_register_cookie(struct super_block *sb,
>> +						struct erofs_fscache **fscache,
>> +						char *name, bool need_inode)
>> +{
>> +	return -EOPNOTSUPP;
>> +}
>>   
>>   static inline void erofs_fscache_unregister_cookie(struct erofs_fscache **fscache)
>>   {
>> diff --git a/fs/erofs/super.c b/fs/erofs/super.c
>> index 667a78f0ee70..11c5ba84567c 100644
>> --- a/fs/erofs/super.c
>> +++ b/fs/erofs/super.c
>> @@ -245,8 +245,12 @@ static int erofs_init_device(struct erofs_buf *buf, struct super_block *sb,
>>   	}
>>   
>>   	if (erofs_is_fscache_mode(sb)) {
>> -		ret = erofs_fscache_register_cookie(sb, &dif->fscache,
>> -				dif->path, false);
>> +		if (sbi->opt.domain_id)
>> +			ret = erofs_domain_register_cookie(sb, &dif->fscache, dif->path,
>> +					false);
>> +		else
>> +			ret = erofs_fscache_register_cookie(sb, &dif->fscache, dif->path,
>> +					false);
>>   		if (ret)
>>   			return ret;
>>   	} else {
>> @@ -726,6 +730,8 @@ static int erofs_fc_fill_super(struct super_block *sb, struct fs_context *fc)
>>   			err = erofs_fscache_register_domain(sb);
>>   			if (err)
>>   				return err;
>> +			err = erofs_domain_register_cookie(sb, &sbi->s_fscache,
>> +					sbi->opt.fsid, true);
>>   		} else {
>>   			err = erofs_fscache_register_fs(sb);
>>   			if (err)
>

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