[RFC,v3.1,3/6] btrfs: qgroup: Return actually freed bytes for qgroup release or free data
diff mbox

Message ID 20170512033046.31981-4-quwenruo@cn.fujitsu.com
State New
Headers show

Commit Message

Qu Wenruo May 12, 2017, 3:30 a.m. UTC
btrfs_qgroup_release/free_data() only returns 0 or minus error
number(ENOMEM is the only possible error).

This is normally good enough, but sometimes we need the accurate byte
number it freed/released.

Change it to return actually released/freed bytenr number instead of 0
for success.
And slightly modify related extent_changeset structure, since in btrfs
one none-hole data extent won't be larger than 128M, so "unsigned int"
is large enough for the use case.

Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
---
 fs/btrfs/extent-tree.c | 2 +-
 fs/btrfs/extent_io.h   | 2 +-
 fs/btrfs/qgroup.c      | 1 +
 3 files changed, 3 insertions(+), 2 deletions(-)

Comments

David Sterba May 16, 2017, 2:23 p.m. UTC | #1
On Fri, May 12, 2017 at 11:30:43AM +0800, Qu Wenruo wrote:
> btrfs_qgroup_release/free_data() only returns 0 or minus error
> number(ENOMEM is the only possible error).

"btrfs_qgroup_release/free_data() only returns 0 or a negative error
number (ENOMEM is the only possible error)."

> This is normally good enough, but sometimes we need the accurate byte
> number it freed/released.
> 
> Change it to return actually released/freed bytenr number instead of 0
> for success.
> And slightly modify related extent_changeset structure, since in btrfs
> one none-hole data extent won't be larger than 128M, so "unsigned int"
      ^^^^^^^^^
      NO_HOLES or no-hole

> is large enough for the use case.
> 
> Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
> ---
>  fs/btrfs/extent-tree.c | 2 +-
>  fs/btrfs/extent_io.h   | 2 +-
>  fs/btrfs/qgroup.c      | 1 +
>  3 files changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
> index e390451c72e6..4f62696131a6 100644
> --- a/fs/btrfs/extent-tree.c
> +++ b/fs/btrfs/extent-tree.c
> @@ -4298,7 +4298,7 @@ int btrfs_check_data_free_space(struct inode *inode, u64 start, u64 len)
>  
>  	/* Use new btrfs_qgroup_reserve_data to reserve precious data space. */
>  	ret = btrfs_qgroup_reserve_data(inode, start, len);
> -	if (ret)
> +	if (ret < 0)
>  		btrfs_free_reserved_data_space_noquota(inode, start, len);
>  	return ret;
>  }
> diff --git a/fs/btrfs/extent_io.h b/fs/btrfs/extent_io.h
> index 1eafa2f0ede3..cc1b08fa9fe7 100644
> --- a/fs/btrfs/extent_io.h
> +++ b/fs/btrfs/extent_io.h
> @@ -205,7 +205,7 @@ struct extent_buffer {
>   */
>  struct extent_changeset {
>  	/* How many bytes are set/cleared in this operation */
> -	u64 bytes_changed;
> +	unsigned int bytes_changed;

The alignment constraints will insert 4 bytes anyway, so we don't save
any space, but unsigned int is fine here, as we're not going to utilize u64.

>  	/* Changed ranges */
>  	struct ulist range_changed;
> diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c
> index 9f01c25469f7..ad2e99491395 100644
> --- a/fs/btrfs/qgroup.c
> +++ b/fs/btrfs/qgroup.c
> @@ -2886,6 +2886,7 @@ static int __btrfs_qgroup_release_data(struct inode *inode, u64 start, u64 len,
>  		btrfs_qgroup_free_refroot(BTRFS_I(inode)->root->fs_info,
>  				BTRFS_I(inode)->root->objectid,
>  				changeset.bytes_changed);
> +	ret = changeset.bytes_changed;
>  out:
>  	ulist_release(&changeset.range_changed);
>  	return ret;
> -- 
> 2.12.2
> 
> 
> 
> --
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Qu Wenruo May 17, 2017, 1:12 a.m. UTC | #2
At 05/16/2017 10:23 PM, David Sterba wrote:
> On Fri, May 12, 2017 at 11:30:43AM +0800, Qu Wenruo wrote:
>> btrfs_qgroup_release/free_data() only returns 0 or minus error
>> number(ENOMEM is the only possible error).
> 
> "btrfs_qgroup_release/free_data() only returns 0 or a negative error
> number (ENOMEM is the only possible error)." >
>> This is normally good enough, but sometimes we need the accurate byte
>> number it freed/released.
>>
>> Change it to return actually released/freed bytenr number instead of 0
>> for success.
>> And slightly modify related extent_changeset structure, since in btrfs
>> one none-hole data extent won't be larger than 128M, so "unsigned int"
>        ^^^^^^^^^
>        NO_HOLES or no-hole
> 
>> is large enough for the use case.
>>
>> Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
>> ---
>>   fs/btrfs/extent-tree.c | 2 +-
>>   fs/btrfs/extent_io.h   | 2 +-
>>   fs/btrfs/qgroup.c      | 1 +
>>   3 files changed, 3 insertions(+), 2 deletions(-)
>>
>> diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
>> index e390451c72e6..4f62696131a6 100644
>> --- a/fs/btrfs/extent-tree.c
>> +++ b/fs/btrfs/extent-tree.c
>> @@ -4298,7 +4298,7 @@ int btrfs_check_data_free_space(struct inode *inode, u64 start, u64 len)
>>   
>>   	/* Use new btrfs_qgroup_reserve_data to reserve precious data space. */
>>   	ret = btrfs_qgroup_reserve_data(inode, start, len);
>> -	if (ret)
>> +	if (ret < 0)
>>   		btrfs_free_reserved_data_space_noquota(inode, start, len);
>>   	return ret;
>>   }
>> diff --git a/fs/btrfs/extent_io.h b/fs/btrfs/extent_io.h
>> index 1eafa2f0ede3..cc1b08fa9fe7 100644
>> --- a/fs/btrfs/extent_io.h
>> +++ b/fs/btrfs/extent_io.h
>> @@ -205,7 +205,7 @@ struct extent_buffer {
>>    */
>>   struct extent_changeset {
>>   	/* How many bytes are set/cleared in this operation */
>> -	u64 bytes_changed;
>> +	unsigned int bytes_changed;
> 
> The alignment constraints will insert 4 bytes anyway, so we don't save
> any space, but unsigned int is fine here, as we're not going to utilize u64.

Sorry, I just realized that extent_state in extent_io_tree can be merged 
with each other.

So (state->end - state->start + 1) can overflow unsigned int.

I'll skip this modification in next update, and apply the grammar comment.

Thanks,
Qu

> 
>>   	/* Changed ranges */
>>   	struct ulist range_changed;
>> diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c
>> index 9f01c25469f7..ad2e99491395 100644
>> --- a/fs/btrfs/qgroup.c
>> +++ b/fs/btrfs/qgroup.c
>> @@ -2886,6 +2886,7 @@ static int __btrfs_qgroup_release_data(struct inode *inode, u64 start, u64 len,
>>   		btrfs_qgroup_free_refroot(BTRFS_I(inode)->root->fs_info,
>>   				BTRFS_I(inode)->root->objectid,
>>   				changeset.bytes_changed);
>> +	ret = changeset.bytes_changed;
>>   out:
>>   	ulist_release(&changeset.range_changed);
>>   	return ret;
>> -- 
>> 2.12.2
>>
>>
>>
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> --
> To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> 
> 


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Qu Wenruo May 17, 2017, 1:19 a.m. UTC | #3
At 05/17/2017 09:12 AM, Qu Wenruo wrote:
> 
> 
> At 05/16/2017 10:23 PM, David Sterba wrote:
>> On Fri, May 12, 2017 at 11:30:43AM +0800, Qu Wenruo wrote:
>>> btrfs_qgroup_release/free_data() only returns 0 or minus error
>>> number(ENOMEM is the only possible error).
>>
>> "btrfs_qgroup_release/free_data() only returns 0 or a negative error
>> number (ENOMEM is the only possible error)." >
>>> This is normally good enough, but sometimes we need the accurate byte
>>> number it freed/released.
>>>
>>> Change it to return actually released/freed bytenr number instead of 0
>>> for success.
>>> And slightly modify related extent_changeset structure, since in btrfs
>>> one none-hole data extent won't be larger than 128M, so "unsigned int"
>>        ^^^^^^^^^
>>        NO_HOLES or no-hole
>>
>>> is large enough for the use case.
>>>
>>> Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
>>> ---
>>>   fs/btrfs/extent-tree.c | 2 +-
>>>   fs/btrfs/extent_io.h   | 2 +-
>>>   fs/btrfs/qgroup.c      | 1 +
>>>   3 files changed, 3 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
>>> index e390451c72e6..4f62696131a6 100644
>>> --- a/fs/btrfs/extent-tree.c
>>> +++ b/fs/btrfs/extent-tree.c
>>> @@ -4298,7 +4298,7 @@ int btrfs_check_data_free_space(struct inode 
>>> *inode, u64 start, u64 len)
>>>       /* Use new btrfs_qgroup_reserve_data to reserve precious data 
>>> space. */
>>>       ret = btrfs_qgroup_reserve_data(inode, start, len);
>>> -    if (ret)
>>> +    if (ret < 0)
>>>           btrfs_free_reserved_data_space_noquota(inode, start, len);
>>>       return ret;
>>>   }
>>> diff --git a/fs/btrfs/extent_io.h b/fs/btrfs/extent_io.h
>>> index 1eafa2f0ede3..cc1b08fa9fe7 100644
>>> --- a/fs/btrfs/extent_io.h
>>> +++ b/fs/btrfs/extent_io.h
>>> @@ -205,7 +205,7 @@ struct extent_buffer {
>>>    */
>>>   struct extent_changeset {
>>>       /* How many bytes are set/cleared in this operation */
>>> -    u64 bytes_changed;
>>> +    unsigned int bytes_changed;
>>
>> The alignment constraints will insert 4 bytes anyway, so we don't save
>> any space, but unsigned int is fine here, as we're not going to 
>> utilize u64.
> 
> Sorry, I just realized that extent_state in extent_io_tree can be merged 
> with each other.
> 
> So (state->end - state->start + 1) can overflow unsigned int.

Please ignore this comment.
In context of btrfs_qgroup_reserve_data(), we won't modify ranges out of 
the data extent, which is no larger than 128M.

And all related extent_changeset users are all based on actually 
allocated extent, so we won't overflow unsigned int any way.

Thanks,
Qu

> 
> I'll skip this modification in next update, and apply the grammar comment.
> 
> Thanks,
> Qu
> 
>>
>>>       /* Changed ranges */
>>>       struct ulist range_changed;
>>> diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c
>>> index 9f01c25469f7..ad2e99491395 100644
>>> --- a/fs/btrfs/qgroup.c
>>> +++ b/fs/btrfs/qgroup.c
>>> @@ -2886,6 +2886,7 @@ static int __btrfs_qgroup_release_data(struct 
>>> inode *inode, u64 start, u64 len,
>>>           btrfs_qgroup_free_refroot(BTRFS_I(inode)->root->fs_info,
>>>                   BTRFS_I(inode)->root->objectid,
>>>                   changeset.bytes_changed);
>>> +    ret = changeset.bytes_changed;
>>>   out:
>>>       ulist_release(&changeset.range_changed);
>>>       return ret;
>>> -- 
>>> 2.12.2
>>>
>>>
>>>
>>> -- 
>>> To unsubscribe from this list: send the line "unsubscribe 
>>> linux-btrfs" in
>>> the body of a message to majordomo@vger.kernel.org
>>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>> -- 
>> To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>>
>>


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Patch
diff mbox

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index e390451c72e6..4f62696131a6 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -4298,7 +4298,7 @@  int btrfs_check_data_free_space(struct inode *inode, u64 start, u64 len)
 
 	/* Use new btrfs_qgroup_reserve_data to reserve precious data space. */
 	ret = btrfs_qgroup_reserve_data(inode, start, len);
-	if (ret)
+	if (ret < 0)
 		btrfs_free_reserved_data_space_noquota(inode, start, len);
 	return ret;
 }
diff --git a/fs/btrfs/extent_io.h b/fs/btrfs/extent_io.h
index 1eafa2f0ede3..cc1b08fa9fe7 100644
--- a/fs/btrfs/extent_io.h
+++ b/fs/btrfs/extent_io.h
@@ -205,7 +205,7 @@  struct extent_buffer {
  */
 struct extent_changeset {
 	/* How many bytes are set/cleared in this operation */
-	u64 bytes_changed;
+	unsigned int bytes_changed;
 
 	/* Changed ranges */
 	struct ulist range_changed;
diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c
index 9f01c25469f7..ad2e99491395 100644
--- a/fs/btrfs/qgroup.c
+++ b/fs/btrfs/qgroup.c
@@ -2886,6 +2886,7 @@  static int __btrfs_qgroup_release_data(struct inode *inode, u64 start, u64 len,
 		btrfs_qgroup_free_refroot(BTRFS_I(inode)->root->fs_info,
 				BTRFS_I(inode)->root->objectid,
 				changeset.bytes_changed);
+	ret = changeset.bytes_changed;
 out:
 	ulist_release(&changeset.range_changed);
 	return ret;