2023-05-30 01:50:36

by Wu Bo

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

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 <[email protected]>
---
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

2023-05-30 02:08:35

by Chao Yu

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

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 <[email protected]>

Reviewed-by: Chao Yu <[email protected]>

Thanks,

2023-05-30 23:54:53

by Jaegeuk Kim

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

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 <[email protected]>
> ---
> 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

2023-05-31 01:20:49

by Chao Yu

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

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 <[email protected]>
>> ---
>> 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