[1/3] ocfs2: add ocfs2_try_rw_lock and ocfs2_try_inode_lock
diff mbox

Message ID 1511775987-841-2-git-send-email-ghe@suse.com
State New
Headers show

Commit Message

Gang He Nov. 27, 2017, 9:46 a.m. UTC
Add ocfs2_try_rw_lock and ocfs2_try_inode_lock functions, which
will be used in non-block IO scenarios.

Signed-off-by: Gang He <ghe@suse.com>
---
 fs/ocfs2/dlmglue.c | 22 ++++++++++++++++++++++
 fs/ocfs2/dlmglue.h |  4 ++++
 2 files changed, 26 insertions(+)

Comments

piaojun Nov. 28, 2017, 1:32 a.m. UTC | #1
Hi Gang,

On 2017/11/27 17:46, Gang He wrote:
> Add ocfs2_try_rw_lock and ocfs2_try_inode_lock functions, which
> will be used in non-block IO scenarios.
> 
> Signed-off-by: Gang He <ghe@suse.com>
> ---
>  fs/ocfs2/dlmglue.c | 22 ++++++++++++++++++++++
>  fs/ocfs2/dlmglue.h |  4 ++++
>  2 files changed, 26 insertions(+)
> 
> diff --git a/fs/ocfs2/dlmglue.c b/fs/ocfs2/dlmglue.c
> index 4689940..5cfbd04 100644
> --- a/fs/ocfs2/dlmglue.c
> +++ b/fs/ocfs2/dlmglue.c
> @@ -1742,6 +1742,28 @@ int ocfs2_rw_lock(struct inode *inode, int write)
>  	return status;
>  }
>  
> +int ocfs2_try_rw_lock(struct inode *inode, int write)
> +{
> +	int status, level;
> +	struct ocfs2_lock_res *lockres;
> +	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
> +
> +	mlog(0, "inode %llu try to take %s RW lock\n",
> +	     (unsigned long long)OCFS2_I(inode)->ip_blkno,
> +	     write ? "EXMODE" : "PRMODE");
> +
> +	if (ocfs2_mount_local(osb))
> +		return 0;
> +
> +	lockres = &OCFS2_I(inode)->ip_rw_lockres;
> +
> +	level = write ? DLM_LOCK_EX : DLM_LOCK_PR;
> +
> +	status = ocfs2_cluster_lock(OCFS2_SB(inode->i_sb), lockres, level,
> +				    DLM_LKF_NOQUEUE, 0);

we'd better use 'osb' instead of 'OCFS2_SB(inode->i_sb)'.

> +	return status;
> +}
> +
>  void ocfs2_rw_unlock(struct inode *inode, int write)
>  {
>  	int level = write ? DLM_LOCK_EX : DLM_LOCK_PR;
> diff --git a/fs/ocfs2/dlmglue.h b/fs/ocfs2/dlmglue.h
> index a7fc18b..05910fc 100644
> --- a/fs/ocfs2/dlmglue.h
> +++ b/fs/ocfs2/dlmglue.h
> @@ -116,6 +116,7 @@ void ocfs2_refcount_lock_res_init(struct ocfs2_lock_res *lockres,
>  int ocfs2_create_new_inode_locks(struct inode *inode);
>  int ocfs2_drop_inode_locks(struct inode *inode);
>  int ocfs2_rw_lock(struct inode *inode, int write);
> +int ocfs2_try_rw_lock(struct inode *inode, int write);
>  void ocfs2_rw_unlock(struct inode *inode, int write);
>  int ocfs2_open_lock(struct inode *inode);
>  int ocfs2_try_open_lock(struct inode *inode, int write);
> @@ -140,6 +141,9 @@ int ocfs2_inode_lock_with_page(struct inode *inode,
>  /* 99% of the time we don't want to supply any additional flags --
>   * those are for very specific cases only. */
>  #define ocfs2_inode_lock(i, b, e) ocfs2_inode_lock_full_nested(i, b, e, 0, OI_LS_NORMAL)
> +#define ocfs2_try_inode_lock(i, b, e)\
> +		ocfs2_inode_lock_full_nested(i, b, e, OCFS2_META_LOCK_NOQUEUE,\
> +		OI_LS_NORMAL)
>  void ocfs2_inode_unlock(struct inode *inode,
>  		       int ex);
>  int ocfs2_super_lock(struct ocfs2_super *osb,
>
Changwei Ge Nov. 28, 2017, 1:52 a.m. UTC | #2
Hi Gang,

On 2017/11/27 17:48, Gang He wrote:
> Add ocfs2_try_rw_lock and ocfs2_try_inode_lock functions, which
> will be used in non-block IO scenarios.
> 
> Signed-off-by: Gang He <ghe@suse.com>
> ---
>   fs/ocfs2/dlmglue.c | 22 ++++++++++++++++++++++
>   fs/ocfs2/dlmglue.h |  4 ++++
>   2 files changed, 26 insertions(+)
> 
> diff --git a/fs/ocfs2/dlmglue.c b/fs/ocfs2/dlmglue.c
> index 4689940..5cfbd04 100644
> --- a/fs/ocfs2/dlmglue.c
> +++ b/fs/ocfs2/dlmglue.c
> @@ -1742,6 +1742,28 @@ int ocfs2_rw_lock(struct inode *inode, int write)
>   	return status;
>   }
>   
> +int ocfs2_try_rw_lock(struct inode *inode, int write)
> +{
> +	int status, level;
> +	struct ocfs2_lock_res *lockres;
> +	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
> +
> +	mlog(0, "inode %llu try to take %s RW lock\n",
> +	     (unsigned long long)OCFS2_I(inode)->ip_blkno,
> +	     write ? "EXMODE" : "PRMODE");
> +
> +	if (ocfs2_mount_local(osb))
> +		return 0;
> +
> +	lockres = &OCFS2_I(inode)->ip_rw_lockres;
> +
> +	level = write ? DLM_LOCK_EX : DLM_LOCK_PR;
> +
> +	status = ocfs2_cluster_lock(OCFS2_SB(inode->i_sb), lockres, level,
> +				    DLM_LKF_NOQUEUE, 0);
> +	return status;
> +}

The newly added function ocfs2_try_rw_lock almost has the same logic 
with ocfs2_rw_lock.Is it possible to combine them into an unique one?
That will be more elegant.

Moreover, can you elaborate further why we need a *NOQUEUE* lock for 
supporting non-block aio?

Why can't we wait for a while to grant a lock request? Is this necessary?

Thanks,
Changwei

> +
>   void ocfs2_rw_unlock(struct inode *inode, int write)
>   {
>   	int level = write ? DLM_LOCK_EX : DLM_LOCK_PR;
> diff --git a/fs/ocfs2/dlmglue.h b/fs/ocfs2/dlmglue.h
> index a7fc18b..05910fc 100644
> --- a/fs/ocfs2/dlmglue.h
> +++ b/fs/ocfs2/dlmglue.h
> @@ -116,6 +116,7 @@ void ocfs2_refcount_lock_res_init(struct ocfs2_lock_res *lockres,
>   int ocfs2_create_new_inode_locks(struct inode *inode);
>   int ocfs2_drop_inode_locks(struct inode *inode);
>   int ocfs2_rw_lock(struct inode *inode, int write);
> +int ocfs2_try_rw_lock(struct inode *inode, int write);
>   void ocfs2_rw_unlock(struct inode *inode, int write);
>   int ocfs2_open_lock(struct inode *inode);
>   int ocfs2_try_open_lock(struct inode *inode, int write);
> @@ -140,6 +141,9 @@ int ocfs2_inode_lock_with_page(struct inode *inode,
>   /* 99% of the time we don't want to supply any additional flags --
>    * those are for very specific cases only. */
>   #define ocfs2_inode_lock(i, b, e) ocfs2_inode_lock_full_nested(i, b, e, 0, OI_LS_NORMAL)
> +#define ocfs2_try_inode_lock(i, b, e)\
> +		ocfs2_inode_lock_full_nested(i, b, e, OCFS2_META_LOCK_NOQUEUE,\
> +		OI_LS_NORMAL)
>   void ocfs2_inode_unlock(struct inode *inode,
>   		       int ex);
>   int ocfs2_super_lock(struct ocfs2_super *osb,
>
Gang He Nov. 28, 2017, 5:05 a.m. UTC | #3
Hello Jun,


>>> 
> Hi Gang,
> 
> On 2017/11/27 17:46, Gang He wrote:
>> Add ocfs2_try_rw_lock and ocfs2_try_inode_lock functions, which
>> will be used in non-block IO scenarios.
>> 
>> Signed-off-by: Gang He <ghe@suse.com>
>> ---
>>  fs/ocfs2/dlmglue.c | 22 ++++++++++++++++++++++
>>  fs/ocfs2/dlmglue.h |  4 ++++
>>  2 files changed, 26 insertions(+)
>> 
>> diff --git a/fs/ocfs2/dlmglue.c b/fs/ocfs2/dlmglue.c
>> index 4689940..5cfbd04 100644
>> --- a/fs/ocfs2/dlmglue.c
>> +++ b/fs/ocfs2/dlmglue.c
>> @@ -1742,6 +1742,28 @@ int ocfs2_rw_lock(struct inode *inode, int write)
>>  	return status;
>>  }
>>  
>> +int ocfs2_try_rw_lock(struct inode *inode, int write)
>> +{
>> +	int status, level;
>> +	struct ocfs2_lock_res *lockres;
>> +	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
>> +
>> +	mlog(0, "inode %llu try to take %s RW lock\n",
>> +	     (unsigned long long)OCFS2_I(inode)->ip_blkno,
>> +	     write ? "EXMODE" : "PRMODE");
>> +
>> +	if (ocfs2_mount_local(osb))
>> +		return 0;
>> +
>> +	lockres = &OCFS2_I(inode)->ip_rw_lockres;
>> +
>> +	level = write ? DLM_LOCK_EX : DLM_LOCK_PR;
>> +
>> +	status = ocfs2_cluster_lock(OCFS2_SB(inode->i_sb), lockres, level,
>> +				    DLM_LKF_NOQUEUE, 0);
> 
> we'd better use 'osb' instead of 'OCFS2_SB(inode->i_sb)'.
Ok, I did this change in next version.

> 
>> +	return status;
>> +}
>> +
>>  void ocfs2_rw_unlock(struct inode *inode, int write)
>>  {
>>  	int level = write ? DLM_LOCK_EX : DLM_LOCK_PR;
>> diff --git a/fs/ocfs2/dlmglue.h b/fs/ocfs2/dlmglue.h
>> index a7fc18b..05910fc 100644
>> --- a/fs/ocfs2/dlmglue.h
>> +++ b/fs/ocfs2/dlmglue.h
>> @@ -116,6 +116,7 @@ void ocfs2_refcount_lock_res_init(struct ocfs2_lock_res 
> *lockres,
>>  int ocfs2_create_new_inode_locks(struct inode *inode);
>>  int ocfs2_drop_inode_locks(struct inode *inode);
>>  int ocfs2_rw_lock(struct inode *inode, int write);
>> +int ocfs2_try_rw_lock(struct inode *inode, int write);
>>  void ocfs2_rw_unlock(struct inode *inode, int write);
>>  int ocfs2_open_lock(struct inode *inode);
>>  int ocfs2_try_open_lock(struct inode *inode, int write);
>> @@ -140,6 +141,9 @@ int ocfs2_inode_lock_with_page(struct inode *inode,
>>  /* 99% of the time we don't want to supply any additional flags --
>>   * those are for very specific cases only. */
>>  #define ocfs2_inode_lock(i, b, e) ocfs2_inode_lock_full_nested(i, b, e, 0, 
> OI_LS_NORMAL)
>> +#define ocfs2_try_inode_lock(i, b, e)\
>> +		ocfs2_inode_lock_full_nested(i, b, e, OCFS2_META_LOCK_NOQUEUE,\
>> +		OI_LS_NORMAL)
>>  void ocfs2_inode_unlock(struct inode *inode,
>>  		       int ex);
>>  int ocfs2_super_lock(struct ocfs2_super *osb,
>>
Gang He Nov. 28, 2017, 5:26 a.m. UTC | #4
Hello Changwei,


>>> 
> Hi Gang,
> 
> On 2017/11/27 17:48, Gang He wrote:
>> Add ocfs2_try_rw_lock and ocfs2_try_inode_lock functions, which
>> will be used in non-block IO scenarios.
>> 
>> Signed-off-by: Gang He <ghe@suse.com>
>> ---
>>   fs/ocfs2/dlmglue.c | 22 ++++++++++++++++++++++
>>   fs/ocfs2/dlmglue.h |  4 ++++
>>   2 files changed, 26 insertions(+)
>> 
>> diff --git a/fs/ocfs2/dlmglue.c b/fs/ocfs2/dlmglue.c
>> index 4689940..5cfbd04 100644
>> --- a/fs/ocfs2/dlmglue.c
>> +++ b/fs/ocfs2/dlmglue.c
>> @@ -1742,6 +1742,28 @@ int ocfs2_rw_lock(struct inode *inode, int write)
>>   	return status;
>>   }
>>   
>> +int ocfs2_try_rw_lock(struct inode *inode, int write)
>> +{
>> +	int status, level;
>> +	struct ocfs2_lock_res *lockres;
>> +	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
>> +
>> +	mlog(0, "inode %llu try to take %s RW lock\n",
>> +	     (unsigned long long)OCFS2_I(inode)->ip_blkno,
>> +	     write ? "EXMODE" : "PRMODE");
>> +
>> +	if (ocfs2_mount_local(osb))
>> +		return 0;
>> +
>> +	lockres = &OCFS2_I(inode)->ip_rw_lockres;
>> +
>> +	level = write ? DLM_LOCK_EX : DLM_LOCK_PR;
>> +
>> +	status = ocfs2_cluster_lock(OCFS2_SB(inode->i_sb), lockres, level,
>> +				    DLM_LKF_NOQUEUE, 0);
>> +	return status;
>> +}
> 
> The newly added function ocfs2_try_rw_lock almost has the same logic 
> with ocfs2_rw_lock.Is it possible to combine them into an unique one?
> That will be more elegant.
I prefer to keep ocfs2_try_rw_lock() separately, since there has been the similar function/code here (e.g. ocfs2_try_open_lock).
second, adding a new ocfs2_try_rw_lock() function can avoid impact the existing code.

> 
> Moreover, can you elaborate further why we need a *NOQUEUE* lock for 
> supporting non-block aio?
Non-block IO means that the invoking should return with -EAGAIN instead of being blocked to wait for certain resource (e.g. lock, block allocation, etc.).

> 
> Why can't we wait for a while to grant a lock request? Is this necessary?
Non-block IO is a way for the upper application to submit IO, if the invoking will be blocked, the invoking will failed with -EAGAIN, 
then, the upper application will submit this IO with the normal (block mode) way in a delayed thread, this IO mode will benefit some database application.

> 
> Thanks,
> Changwei
> 
>> +
>>   void ocfs2_rw_unlock(struct inode *inode, int write)
>>   {
>>   	int level = write ? DLM_LOCK_EX : DLM_LOCK_PR;
>> diff --git a/fs/ocfs2/dlmglue.h b/fs/ocfs2/dlmglue.h
>> index a7fc18b..05910fc 100644
>> --- a/fs/ocfs2/dlmglue.h
>> +++ b/fs/ocfs2/dlmglue.h
>> @@ -116,6 +116,7 @@ void ocfs2_refcount_lock_res_init(struct ocfs2_lock_res 
> *lockres,
>>   int ocfs2_create_new_inode_locks(struct inode *inode);
>>   int ocfs2_drop_inode_locks(struct inode *inode);
>>   int ocfs2_rw_lock(struct inode *inode, int write);
>> +int ocfs2_try_rw_lock(struct inode *inode, int write);
>>   void ocfs2_rw_unlock(struct inode *inode, int write);
>>   int ocfs2_open_lock(struct inode *inode);
>>   int ocfs2_try_open_lock(struct inode *inode, int write);
>> @@ -140,6 +141,9 @@ int ocfs2_inode_lock_with_page(struct inode *inode,
>>   /* 99% of the time we don't want to supply any additional flags --
>>    * those are for very specific cases only. */
>>   #define ocfs2_inode_lock(i, b, e) ocfs2_inode_lock_full_nested(i, b, e, 0, 
> OI_LS_NORMAL)
>> +#define ocfs2_try_inode_lock(i, b, e)\
>> +		ocfs2_inode_lock_full_nested(i, b, e, OCFS2_META_LOCK_NOQUEUE,\
>> +		OI_LS_NORMAL)
>>   void ocfs2_inode_unlock(struct inode *inode,
>>   		       int ex);
>>   int ocfs2_super_lock(struct ocfs2_super *osb,
>>

Patch
diff mbox

diff --git a/fs/ocfs2/dlmglue.c b/fs/ocfs2/dlmglue.c
index 4689940..5cfbd04 100644
--- a/fs/ocfs2/dlmglue.c
+++ b/fs/ocfs2/dlmglue.c
@@ -1742,6 +1742,28 @@  int ocfs2_rw_lock(struct inode *inode, int write)
 	return status;
 }
 
+int ocfs2_try_rw_lock(struct inode *inode, int write)
+{
+	int status, level;
+	struct ocfs2_lock_res *lockres;
+	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
+
+	mlog(0, "inode %llu try to take %s RW lock\n",
+	     (unsigned long long)OCFS2_I(inode)->ip_blkno,
+	     write ? "EXMODE" : "PRMODE");
+
+	if (ocfs2_mount_local(osb))
+		return 0;
+
+	lockres = &OCFS2_I(inode)->ip_rw_lockres;
+
+	level = write ? DLM_LOCK_EX : DLM_LOCK_PR;
+
+	status = ocfs2_cluster_lock(OCFS2_SB(inode->i_sb), lockres, level,
+				    DLM_LKF_NOQUEUE, 0);
+	return status;
+}
+
 void ocfs2_rw_unlock(struct inode *inode, int write)
 {
 	int level = write ? DLM_LOCK_EX : DLM_LOCK_PR;
diff --git a/fs/ocfs2/dlmglue.h b/fs/ocfs2/dlmglue.h
index a7fc18b..05910fc 100644
--- a/fs/ocfs2/dlmglue.h
+++ b/fs/ocfs2/dlmglue.h
@@ -116,6 +116,7 @@  void ocfs2_refcount_lock_res_init(struct ocfs2_lock_res *lockres,
 int ocfs2_create_new_inode_locks(struct inode *inode);
 int ocfs2_drop_inode_locks(struct inode *inode);
 int ocfs2_rw_lock(struct inode *inode, int write);
+int ocfs2_try_rw_lock(struct inode *inode, int write);
 void ocfs2_rw_unlock(struct inode *inode, int write);
 int ocfs2_open_lock(struct inode *inode);
 int ocfs2_try_open_lock(struct inode *inode, int write);
@@ -140,6 +141,9 @@  int ocfs2_inode_lock_with_page(struct inode *inode,
 /* 99% of the time we don't want to supply any additional flags --
  * those are for very specific cases only. */
 #define ocfs2_inode_lock(i, b, e) ocfs2_inode_lock_full_nested(i, b, e, 0, OI_LS_NORMAL)
+#define ocfs2_try_inode_lock(i, b, e)\
+		ocfs2_inode_lock_full_nested(i, b, e, OCFS2_META_LOCK_NOQUEUE,\
+		OI_LS_NORMAL)
 void ocfs2_inode_unlock(struct inode *inode,
 		       int ex);
 int ocfs2_super_lock(struct ocfs2_super *osb,