[f2fs-dev] [PATCH v2 1/1] f2fs: fix args passed to trace_f2fs_lookup_end

[f2fs-dev] [PATCH v2 1/1] f2fs: fix args passed to trace_f2fs_lookup_end

[Wu Bo via Linux-f2fs-devel]

The NULL return of 'd_splice_alias' dosen't mean error. Thus the
successful case will also return NULL, which makes the tracepoint always
print 'err=-ENOENT'.

Signed-off-by: Wu Bo <bo.wu@vivo.com>
---
 fs/f2fs/namei.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/fs/f2fs/namei.c b/fs/f2fs/namei.c
index 77a71276ecb1..0c5e4c424eab 100644
--- a/fs/f2fs/namei.c
+++ b/fs/f2fs/namei.c
@@ -576,8 +576,9 @@ static struct dentry *f2fs_lookup(struct inode *dir, struct dentry *dentry,
 	}
 #endif
 	new = d_splice_alias(inode, dentry);
-	err = PTR_ERR_OR_ZERO(new);
-	trace_f2fs_lookup_end(dir, dentry, ino, !new ? -ENOENT : err);
+	if (IS_ERR(new))
+		err = PTR_ERR(new);
+	trace_f2fs_lookup_end(dir, new ? new : dentry, ino, err);
 	return new;
 out_iput:
 	iput(inode);
-- 
2.35.3



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Re: [f2fs-dev] [PATCH v2 1/1] f2fs: fix args passed to trace_f2fs_lookup_end

[Chao Yu]

On 2023/5/30 9:21, Wu Bo wrote:
> The NULL return of 'd_splice_alias' dosen't mean error. Thus the
> successful case will also return NULL, which makes the tracepoint always
> print 'err=-ENOENT'.
> 
> Signed-off-by: Wu Bo <bo.wu@vivo.com>

Reviewed-by: Chao Yu <chao@kernel.org>

Thanks,


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Re: [f2fs-dev] [PATCH v2 1/1] f2fs: fix args passed to trace_f2fs_lookup_end

[Jaegeuk Kim]

On 05/30, Wu Bo wrote:
> The NULL return of 'd_splice_alias' dosen't mean error. Thus the
> successful case will also return NULL, which makes the tracepoint always
> print 'err=-ENOENT'.
> 
> Signed-off-by: Wu Bo <bo.wu@vivo.com>
> ---
>  fs/f2fs/namei.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/fs/f2fs/namei.c b/fs/f2fs/namei.c
> index 77a71276ecb1..0c5e4c424eab 100644
> --- a/fs/f2fs/namei.c
> +++ b/fs/f2fs/namei.c
> @@ -576,8 +576,9 @@ static struct dentry *f2fs_lookup(struct inode *dir, struct dentry *dentry,
>  	}
>  #endif
>  	new = d_splice_alias(inode, dentry);
> -	err = PTR_ERR_OR_ZERO(new);
> -	trace_f2fs_lookup_end(dir, dentry, ino, !new ? -ENOENT : err);
> +	if (IS_ERR(new))
> +		err = PTR_ERR(new);
> +	trace_f2fs_lookup_end(dir, new ? new : dentry, ino, err);

Again, new can be an error pointer, and the previous err was supposed to be
zero or -ENOENT.

case 1) dentry exists: err (0) with new (NULL) --> dentry, err=0
case 2) dentry exists: err (0) with new (VALID) --> new, err=0
case 3) dentry exists: err (0) with new (ERR) --> dentry, err=ERR
case 4) no dentry exists: err (-ENOENT) with new (NULL) --> dentry, err=-ENOENT
case 4) no dentry exists: err (-ENOENT) with new (VALID) --> new, err=-ENOENT
case 5) no dentry exists: err (-ENOENT) with new (ERR) --> dentry, err=ERR

	trace_f2fs_lookup_end(dir, !IS_ERR_OR_NULL(new) ? new : dentry,
				ino, IS_ERR(new) ? PTR_ERR(new) : err);


>  	return new;
>  out_iput:
>  	iput(inode);
> -- 
> 2.35.3


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Re: [f2fs-dev] [PATCH v2 1/1] f2fs: fix args passed to trace_f2fs_lookup_end

[Chao Yu]

On 2023/5/31 7:32, Jaegeuk Kim wrote:
> On 05/30, Wu Bo wrote:
>> The NULL return of 'd_splice_alias' dosen't mean error. Thus the
>> successful case will also return NULL, which makes the tracepoint always
>> print 'err=-ENOENT'.
>>
>> Signed-off-by: Wu Bo <bo.wu@vivo.com>
>> ---
>>   fs/f2fs/namei.c | 5 +++--
>>   1 file changed, 3 insertions(+), 2 deletions(-)
>>
>> diff --git a/fs/f2fs/namei.c b/fs/f2fs/namei.c
>> index 77a71276ecb1..0c5e4c424eab 100644
>> --- a/fs/f2fs/namei.c
>> +++ b/fs/f2fs/namei.c
>> @@ -576,8 +576,9 @@ static struct dentry *f2fs_lookup(struct inode *dir, struct dentry *dentry,
>>   	}
>>   #endif
>>   	new = d_splice_alias(inode, dentry);
>> -	err = PTR_ERR_OR_ZERO(new);
>> -	trace_f2fs_lookup_end(dir, dentry, ino, !new ? -ENOENT : err);
>> +	if (IS_ERR(new))
>> +		err = PTR_ERR(new);
>> +	trace_f2fs_lookup_end(dir, new ? new : dentry, ino, err);
> 
> Again, new can be an error pointer, and the previous err was supposed to be
> zero or -ENOENT.
> 
> case 1) dentry exists: err (0) with new (NULL) --> dentry, err=0
> case 2) dentry exists: err (0) with new (VALID) --> new, err=0
> case 3) dentry exists: err (0) with new (ERR) --> dentry, err=ERR
> case 4) no dentry exists: err (-ENOENT) with new (NULL) --> dentry, err=-ENOENT
> case 4) no dentry exists: err (-ENOENT) with new (VALID) --> new, err=-ENOENT
> case 5) no dentry exists: err (-ENOENT) with new (ERR) --> dentry, err=ERR
> 
> 	trace_f2fs_lookup_end(dir, !IS_ERR_OR_NULL(new) ? new : dentry,
> 				ino, IS_ERR(new) ? PTR_ERR(new) : err);

Agreed, could you please add above description in commit message?

Thanks,

> 
> 
>>   	return new;
>>   out_iput:
>>   	iput(inode);
>> -- 
>> 2.35.3


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