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[PATCH] f2fs: fix to access i_size w/ i_size_read()

Chao Yu posted 1 patch 1 month, 2 weeks ago 
include/trace/events/f2fs.h | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
[PATCH] f2fs: fix to access i_size w/ i_size_read()
Posted by Chao Yu 1 month, 2 weeks ago 
It recommends to use i_size_{read,write}() to access and update i_size,
otherwise, we may get wrong tearing value due to high 32-bits value
and low 32-bits value of i_size field are not updated atomically in
32-bits archicture machine.

Signed-off-by: Chao Yu <chao@kernel.org>
---
 include/trace/events/f2fs.h | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/include/trace/events/f2fs.h b/include/trace/events/f2fs.h
index edbbd869078f..e1fae78d64a5 100644
--- a/include/trace/events/f2fs.h
+++ b/include/trace/events/f2fs.h
@@ -204,7 +204,7 @@ DECLARE_EVENT_CLASS(f2fs__inode,
 		__entry->pino	= F2FS_I(inode)->i_pino;
 		__entry->mode	= inode->i_mode;
 		__entry->nlink	= inode->i_nlink;
-		__entry->size	= inode->i_size;
+		__entry->size	= i_size_read(inode);
 		__entry->blocks	= inode->i_blocks;
 		__entry->advise	= F2FS_I(inode)->i_advise;
 	),
@@ -353,7 +353,7 @@ TRACE_EVENT(f2fs_unlink_enter,
 	TP_fast_assign(
 		__entry->dev	= dir->i_sb->s_dev;
 		__entry->ino	= dir->i_ino;
-		__entry->size	= dir->i_size;
+		__entry->size	= i_size_read(dir);
 		__entry->blocks	= dir->i_blocks;
 		__assign_str(name);
 	),
@@ -433,7 +433,7 @@ DECLARE_EVENT_CLASS(f2fs__truncate_op,
 	TP_fast_assign(
 		__entry->dev	= inode->i_sb->s_dev;
 		__entry->ino	= inode->i_ino;
-		__entry->size	= inode->i_size;
+		__entry->size	= i_size_read(inode);
 		__entry->blocks	= inode->i_blocks;
 		__entry->from	= from;
 	),
@@ -1006,7 +1006,7 @@ TRACE_EVENT(f2fs_fallocate,
 		__entry->mode	= mode;
 		__entry->offset	= offset;
 		__entry->len	= len;
-		__entry->size	= inode->i_size;
+		__entry->size	= i_size_read(inode);
 		__entry->blocks = inode->i_blocks;
 		__entry->ret	= ret;
 	),
-- 
2.49.0
Re: [f2fs-dev] [PATCH] f2fs: fix to access i_size w/ i_size_read()
Posted by Yongpeng Yang 1 month, 2 weeks ago 
On 10/29/25 14:31, Chao Yu via Linux-f2fs-devel wrote:
> It recommends to use i_size_{read,write}() to access and update i_size,
> otherwise, we may get wrong tearing value due to high 32-bits value
> and low 32-bits value of i_size field are not updated atomically in
> 32-bits archicture machine.
> 
> Signed-off-by: Chao Yu <chao@kernel.org>
> ---
>   include/trace/events/f2fs.h | 8 ++++----
>   1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/include/trace/events/f2fs.h b/include/trace/events/f2fs.h
> index edbbd869078f..e1fae78d64a5 100644
> --- a/include/trace/events/f2fs.h
> +++ b/include/trace/events/f2fs.h
> @@ -204,7 +204,7 @@ DECLARE_EVENT_CLASS(f2fs__inode,
>   		__entry->pino	= F2FS_I(inode)->i_pino;
>   		__entry->mode	= inode->i_mode;
>   		__entry->nlink	= inode->i_nlink;
> -		__entry->size	= inode->i_size;
> +		__entry->size	= i_size_read(inode);
>   		__entry->blocks	= inode->i_blocks;
>   		__entry->advise	= F2FS_I(inode)->i_advise;
>   	),
> @@ -353,7 +353,7 @@ TRACE_EVENT(f2fs_unlink_enter,
>   	TP_fast_assign(
>   		__entry->dev	= dir->i_sb->s_dev;
>   		__entry->ino	= dir->i_ino;
> -		__entry->size	= dir->i_size;
> +		__entry->size	= i_size_read(dir);
>   		__entry->blocks	= dir->i_blocks;
>   		__assign_str(name);
>   	),
> @@ -433,7 +433,7 @@ DECLARE_EVENT_CLASS(f2fs__truncate_op,
>   	TP_fast_assign(
>   		__entry->dev	= inode->i_sb->s_dev;
>   		__entry->ino	= inode->i_ino;
> -		__entry->size	= inode->i_size;
> +		__entry->size	= i_size_read(inode);
>   		__entry->blocks	= inode->i_blocks;
>   		__entry->from	= from;
>   	),
> @@ -1006,7 +1006,7 @@ TRACE_EVENT(f2fs_fallocate,
>   		__entry->mode	= mode;
>   		__entry->offset	= offset;
>   		__entry->len	= len;
> -		__entry->size	= inode->i_size;
> +		__entry->size	= i_size_read(inode);
>   		__entry->blocks = inode->i_blocks;
>   		__entry->ret	= ret;
>   	),

inode->i_size usage in fs/f2fs/ also needs to be updated. For example in 
f2fs_need_verity(), which may not protected by inode_lock.

Yongpeng,
Re: [f2fs-dev] [PATCH] f2fs: fix to access i_size w/ i_size_read()
Posted by Chao Yu 1 month, 2 weeks ago 
On 10/29/25 16:09, Yongpeng Yang wrote:
> On 10/29/25 14:31, Chao Yu via Linux-f2fs-devel wrote:
>> It recommends to use i_size_{read,write}() to access and update i_size,
>> otherwise, we may get wrong tearing value due to high 32-bits value
>> and low 32-bits value of i_size field are not updated atomically in
>> 32-bits archicture machine.
>>
>> Signed-off-by: Chao Yu <chao@kernel.org>
>> ---
>>   include/trace/events/f2fs.h | 8 ++++----
>>   1 file changed, 4 insertions(+), 4 deletions(-)
>>
>> diff --git a/include/trace/events/f2fs.h b/include/trace/events/f2fs.h
>> index edbbd869078f..e1fae78d64a5 100644
>> --- a/include/trace/events/f2fs.h
>> +++ b/include/trace/events/f2fs.h
>> @@ -204,7 +204,7 @@ DECLARE_EVENT_CLASS(f2fs__inode,
>>           __entry->pino    = F2FS_I(inode)->i_pino;
>>           __entry->mode    = inode->i_mode;
>>           __entry->nlink    = inode->i_nlink;
>> -        __entry->size    = inode->i_size;
>> +        __entry->size    = i_size_read(inode);
>>           __entry->blocks    = inode->i_blocks;
>>           __entry->advise    = F2FS_I(inode)->i_advise;
>>       ),
>> @@ -353,7 +353,7 @@ TRACE_EVENT(f2fs_unlink_enter,
>>       TP_fast_assign(
>>           __entry->dev    = dir->i_sb->s_dev;
>>           __entry->ino    = dir->i_ino;
>> -        __entry->size    = dir->i_size;
>> +        __entry->size    = i_size_read(dir);
>>           __entry->blocks    = dir->i_blocks;
>>           __assign_str(name);
>>       ),
>> @@ -433,7 +433,7 @@ DECLARE_EVENT_CLASS(f2fs__truncate_op,
>>       TP_fast_assign(
>>           __entry->dev    = inode->i_sb->s_dev;
>>           __entry->ino    = inode->i_ino;
>> -        __entry->size    = inode->i_size;
>> +        __entry->size    = i_size_read(inode);
>>           __entry->blocks    = inode->i_blocks;
>>           __entry->from    = from;
>>       ),
>> @@ -1006,7 +1006,7 @@ TRACE_EVENT(f2fs_fallocate,
>>           __entry->mode    = mode;
>>           __entry->offset    = offset;
>>           __entry->len    = len;
>> -        __entry->size    = inode->i_size;
>> +        __entry->size    = i_size_read(inode);
>>           __entry->blocks = inode->i_blocks;
>>           __entry->ret    = ret;
>>       ),
> 
> inode->i_size usage in fs/f2fs/ also needs to be updated. For example in f2fs_need_verity(), which may not protected by inode_lock.

Accessing i_size directly in f2fs_need_verity() should be fine? Because fsverity
actived inode should be readonly.

Do you see any other cases which are not covered by inode_lock()?

Thanks,

> 
> Yongpeng,
Re: [f2fs-dev] [PATCH] f2fs: fix to access i_size w/ i_size_read()
Posted by Yongpeng Yang 1 month, 2 weeks ago 
On 10/29/25 17:41, Chao Yu via Linux-f2fs-devel wrote:
> On 10/29/25 16:09, Yongpeng Yang wrote:
>> On 10/29/25 14:31, Chao Yu via Linux-f2fs-devel wrote:
>>> It recommends to use i_size_{read,write}() to access and update i_size,
>>> otherwise, we may get wrong tearing value due to high 32-bits value
>>> and low 32-bits value of i_size field are not updated atomically in
>>> 32-bits archicture machine.
>>>
>>> Signed-off-by: Chao Yu <chao@kernel.org>
>>> ---
>>>    include/trace/events/f2fs.h | 8 ++++----
>>>    1 file changed, 4 insertions(+), 4 deletions(-)
>>>
>>> diff --git a/include/trace/events/f2fs.h b/include/trace/events/f2fs.h
>>> index edbbd869078f..e1fae78d64a5 100644
>>> --- a/include/trace/events/f2fs.h
>>> +++ b/include/trace/events/f2fs.h
>>> @@ -204,7 +204,7 @@ DECLARE_EVENT_CLASS(f2fs__inode,
>>>            __entry->pino    = F2FS_I(inode)->i_pino;
>>>            __entry->mode    = inode->i_mode;
>>>            __entry->nlink    = inode->i_nlink;
>>> -        __entry->size    = inode->i_size;
>>> +        __entry->size    = i_size_read(inode);
>>>            __entry->blocks    = inode->i_blocks;
>>>            __entry->advise    = F2FS_I(inode)->i_advise;
>>>        ),
>>> @@ -353,7 +353,7 @@ TRACE_EVENT(f2fs_unlink_enter,
>>>        TP_fast_assign(
>>>            __entry->dev    = dir->i_sb->s_dev;
>>>            __entry->ino    = dir->i_ino;
>>> -        __entry->size    = dir->i_size;
>>> +        __entry->size    = i_size_read(dir);
>>>            __entry->blocks    = dir->i_blocks;
>>>            __assign_str(name);
>>>        ),
>>> @@ -433,7 +433,7 @@ DECLARE_EVENT_CLASS(f2fs__truncate_op,
>>>        TP_fast_assign(
>>>            __entry->dev    = inode->i_sb->s_dev;
>>>            __entry->ino    = inode->i_ino;
>>> -        __entry->size    = inode->i_size;
>>> +        __entry->size    = i_size_read(inode);
>>>            __entry->blocks    = inode->i_blocks;
>>>            __entry->from    = from;
>>>        ),
>>> @@ -1006,7 +1006,7 @@ TRACE_EVENT(f2fs_fallocate,
>>>            __entry->mode    = mode;
>>>            __entry->offset    = offset;
>>>            __entry->len    = len;
>>> -        __entry->size    = inode->i_size;
>>> +        __entry->size    = i_size_read(inode);
>>>            __entry->blocks = inode->i_blocks;
>>>            __entry->ret    = ret;
>>>        ),
>>
>> inode->i_size usage in fs/f2fs/ also needs to be updated. For example in f2fs_need_verity(), which may not protected by inode_lock.
> 
> Accessing i_size directly in f2fs_need_verity() should be fine? Because fsverity
> actived inode should be readonly.

Yes, it's fine.>
> Do you see any other cases which are not covered by inode_lock()?

I checked again, no other cases.:)>
> Thanks,
> 
>>
>> Yongpeng,
> 
> 
> 
> _______________________________________________
> Linux-f2fs-devel mailing list
> Linux-f2fs-devel@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel

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