[PATCH 1/1] f2fs: allocate trace path buffer from names_cache

[PATCH 1/1] f2fs: allocate trace path buffer from names_cache

[Wu Bo]

It would be better to use the dedicated slab to store path.

Signed-off-by: Wu Bo <bo.wu@vivo.com>
---
 fs/f2fs/file.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index 15dabeac4690..27137873958f 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -4361,7 +4361,7 @@ static void f2fs_trace_rw_file_path(struct kiocb *iocb, size_t count, int rw)
 	struct inode *inode = file_inode(iocb->ki_filp);
 	char *buf, *path;
 
-	buf = f2fs_kmalloc(F2FS_I_SB(inode), PATH_MAX, GFP_KERNEL);
+	buf = __getname();
 	if (!buf)
 		return;
 	path = dentry_path_raw(file_dentry(iocb->ki_filp), buf, PATH_MAX);
@@ -4374,7 +4374,7 @@ static void f2fs_trace_rw_file_path(struct kiocb *iocb, size_t count, int rw)
 		trace_f2fs_dataread_start(inode, iocb->ki_pos, count,
 				current->pid, path, current->comm);
 free_buf:
-	kfree(buf);
+	__putname(buf);
 }
 
 static ssize_t f2fs_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
-- 
2.35.3

Re: [PATCH 1/1] f2fs: allocate trace path buffer from names_cache

[Chao Yu]

On 2023/4/14 18:43, Wu Bo wrote:
> It would be better to use the dedicated slab to store path.
> 
> Signed-off-by: Wu Bo <bo.wu@vivo.com>
> ---
>   fs/f2fs/file.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
> index 15dabeac4690..27137873958f 100644
> --- a/fs/f2fs/file.c
> +++ b/fs/f2fs/file.c
> @@ -4361,7 +4361,7 @@ static void f2fs_trace_rw_file_path(struct kiocb *iocb, size_t count, int rw)
>   	struct inode *inode = file_inode(iocb->ki_filp);
>   	char *buf, *path;
>   
> -	buf = f2fs_kmalloc(F2FS_I_SB(inode), PATH_MAX, GFP_KERNEL);
> +	buf = __getname();

How about:

buf = f2fs_kmem_cache_alloc(names_cachep, GFP_KERNEL, NULL, F2FS_I_SB(inode));

>   	if (!buf)
>   		return;
>   	path = dentry_path_raw(file_dentry(iocb->ki_filp), buf, PATH_MAX);
> @@ -4374,7 +4374,7 @@ static void f2fs_trace_rw_file_path(struct kiocb *iocb, size_t count, int rw)
>   		trace_f2fs_dataread_start(inode, iocb->ki_pos, count,
>   				current->pid, path, current->comm);
>   free_buf:
> -	kfree(buf);
> +	__putname(buf);

kmem_cache_free(names_cachep, buf);

Thanks,

>   }
>   
>   static ssize_t f2fs_file_read_iter(struct kiocb *iocb, struct iov_iter *to)

Re: [PATCH 1/1] f2fs: allocate trace path buffer from names_cache

[Jaegeuk Kim]

On 04/18, Chao Yu wrote:
> On 2023/4/14 18:43, Wu Bo wrote:
> > It would be better to use the dedicated slab to store path.
> > 
> > Signed-off-by: Wu Bo <bo.wu@vivo.com>
> > ---
> >   fs/f2fs/file.c | 4 ++--
> >   1 file changed, 2 insertions(+), 2 deletions(-)
> > 
> > diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
> > index 15dabeac4690..27137873958f 100644
> > --- a/fs/f2fs/file.c
> > +++ b/fs/f2fs/file.c
> > @@ -4361,7 +4361,7 @@ static void f2fs_trace_rw_file_path(struct kiocb *iocb, size_t count, int rw)
> >   	struct inode *inode = file_inode(iocb->ki_filp);
> >   	char *buf, *path;
> > -	buf = f2fs_kmalloc(F2FS_I_SB(inode), PATH_MAX, GFP_KERNEL);
> > +	buf = __getname();
> 
> How about:
> 
> buf = f2fs_kmem_cache_alloc(names_cachep, GFP_KERNEL, NULL, F2FS_I_SB(inode));

This looks like a hack using names_cachep?

> 
> >   	if (!buf)
> >   		return;
> >   	path = dentry_path_raw(file_dentry(iocb->ki_filp), buf, PATH_MAX);
> > @@ -4374,7 +4374,7 @@ static void f2fs_trace_rw_file_path(struct kiocb *iocb, size_t count, int rw)
> >   		trace_f2fs_dataread_start(inode, iocb->ki_pos, count,
> >   				current->pid, path, current->comm);
> >   free_buf:
> > -	kfree(buf);
> > +	__putname(buf);
> 
> kmem_cache_free(names_cachep, buf);
> 
> Thanks,
> 
> >   }
> >   static ssize_t f2fs_file_read_iter(struct kiocb *iocb, struct iov_iter *to)

Re: [f2fs-dev] [PATCH 1/1] f2fs: allocate trace path buffer from names_cache

[Wu Bo]

On 2023/4/18 23:51, Chao Yu wrote:
> On 2023/4/14 18:43, Wu Bo wrote:
>> It would be better to use the dedicated slab to store path.
>>
>> Signed-off-by: Wu Bo <bo.wu@vivo.com>
>> ---
>>   fs/f2fs/file.c | 4 ++--
>>   1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
>> index 15dabeac4690..27137873958f 100644
>> --- a/fs/f2fs/file.c
>> +++ b/fs/f2fs/file.c
>> @@ -4361,7 +4361,7 @@ static void f2fs_trace_rw_file_path(struct
>> kiocb *iocb, size_t count, int rw)
>>       struct inode *inode = file_inode(iocb->ki_filp);
>>       char *buf, *path;
>>   -    buf = f2fs_kmalloc(F2FS_I_SB(inode), PATH_MAX, GFP_KERNEL);
>> +    buf = __getname();
>
> How about:
>
> buf = f2fs_kmem_cache_alloc(names_cachep, GFP_KERNEL, NULL,
> F2FS_I_SB(inode));

Using f2fs_kmem_cache_alloc is able to inject malloc error.
But here is a trace event, is it ok to inject error in a trace path?

>
>>       if (!buf)
>>           return;
>>       path = dentry_path_raw(file_dentry(iocb->ki_filp), buf, PATH_MAX);
>> @@ -4374,7 +4374,7 @@ static void f2fs_trace_rw_file_path(struct
>> kiocb *iocb, size_t count, int rw)
>>           trace_f2fs_dataread_start(inode, iocb->ki_pos, count,
>>                   current->pid, path, current->comm);
>>   free_buf:
>> -    kfree(buf);
>> +    __putname(buf);
>
> kmem_cache_free(names_cachep, buf);
>
> Thanks,
>
>>   }
>>     static ssize_t f2fs_file_read_iter(struct kiocb *iocb, struct
>> iov_iter *to)
>
>
> _______________________________________________
> Linux-f2fs-devel mailing list
> Linux-f2fs-devel@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
>

Re: [PATCH 1/1] f2fs: allocate trace path buffer from names_cache

[Chao Yu]

On 2023/4/19 0:07, Jaegeuk Kim wrote:
> On 04/18, Chao Yu wrote:
>> On 2023/4/14 18:43, Wu Bo wrote:
>>> It would be better to use the dedicated slab to store path.
>>>
>>> Signed-off-by: Wu Bo <bo.wu@vivo.com>
>>> ---
>>>    fs/f2fs/file.c | 4 ++--
>>>    1 file changed, 2 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
>>> index 15dabeac4690..27137873958f 100644
>>> --- a/fs/f2fs/file.c
>>> +++ b/fs/f2fs/file.c
>>> @@ -4361,7 +4361,7 @@ static void f2fs_trace_rw_file_path(struct kiocb *iocb, size_t count, int rw)
>>>    	struct inode *inode = file_inode(iocb->ki_filp);
>>>    	char *buf, *path;
>>> -	buf = f2fs_kmalloc(F2FS_I_SB(inode), PATH_MAX, GFP_KERNEL);
>>> +	buf = __getname();
>>
>> How about:
>>
>> buf = f2fs_kmem_cache_alloc(names_cachep, GFP_KERNEL, NULL, F2FS_I_SB(inode));
> 
> This looks like a hack using names_cachep?

names_cachep was exported in fs.h.

 > Using f2fs_kmem_cache_alloc is able to inject malloc error.
 > But here is a trace event, is it ok to inject error in a trace path?

Yes, the fail path handling is very simple, so it's fine to leave it
as it is.

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

Thanks,

> 
>>
>>>    	if (!buf)
>>>    		return;
>>>    	path = dentry_path_raw(file_dentry(iocb->ki_filp), buf, PATH_MAX);
>>> @@ -4374,7 +4374,7 @@ static void f2fs_trace_rw_file_path(struct kiocb *iocb, size_t count, int rw)
>>>    		trace_f2fs_dataread_start(inode, iocb->ki_pos, count,
>>>    				current->pid, path, current->comm);
>>>    free_buf:
>>> -	kfree(buf);
>>> +	__putname(buf);
>>
>> kmem_cache_free(names_cachep, buf);
>>
>> Thanks,
>>
>>>    }
>>>    static ssize_t f2fs_file_read_iter(struct kiocb *iocb, struct iov_iter *to)

Re: [PATCH 1/1] f2fs: allocate trace path buffer from names_cache

[Jaegeuk Kim]

On 04/19, Chao Yu wrote:
> On 2023/4/19 0:07, Jaegeuk Kim wrote:
> > On 04/18, Chao Yu wrote:
> > > On 2023/4/14 18:43, Wu Bo wrote:
> > > > It would be better to use the dedicated slab to store path.
> > > > 
> > > > Signed-off-by: Wu Bo <bo.wu@vivo.com>
> > > > ---
> > > >    fs/f2fs/file.c | 4 ++--
> > > >    1 file changed, 2 insertions(+), 2 deletions(-)
> > > > 
> > > > diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
> > > > index 15dabeac4690..27137873958f 100644
> > > > --- a/fs/f2fs/file.c
> > > > +++ b/fs/f2fs/file.c
> > > > @@ -4361,7 +4361,7 @@ static void f2fs_trace_rw_file_path(struct kiocb *iocb, size_t count, int rw)
> > > >    	struct inode *inode = file_inode(iocb->ki_filp);
> > > >    	char *buf, *path;
> > > > -	buf = f2fs_kmalloc(F2FS_I_SB(inode), PATH_MAX, GFP_KERNEL);
> > > > +	buf = __getname();
> > > 
> > > How about:
> > > 
> > > buf = f2fs_kmem_cache_alloc(names_cachep, GFP_KERNEL, NULL, F2FS_I_SB(inode));
> > 
> > This looks like a hack using names_cachep?
> 
> names_cachep was exported in fs.h.

I think that's for __getname() in general, which doesn't indicate you can hack.
No one is using like that.

$ grep names_cachep fs/* -R
fs/dcache.c:struct kmem_cache *names_cachep __read_mostly;
fs/dcache.c:EXPORT_SYMBOL(names_cachep);
fs/dcache.c:	names_cachep = kmem_cache_create_usercopy("names_cache", PATH_MAX, 0,

$ grep __getname fs/* -R
fs/ceph/mds_client.c:	path = __getname();
fs/cifs/cifsproto.h:	return __getname();
fs/dcache.c:/* SLAB cache for __getname() consumers */
fs/d_path.c:	char *page = __getname();
fs/exfat/dir.c:	nb->lfn = __getname();
fs/f2fs/file.c:	buf = __getname();
fs/fat/dir.c:		*unicode = __getname();
fs/fat/namei_vfat.c:	uname = __getname();
fs/hostfs/hostfs_kern.c:	char *name = __getname();
fs/namei.c:	result = __getname();
fs/namei.c:	result = __getname();
fs/ntfs3/dir.c:	name = __getname();
fs/ntfs3/xattr.c:	buf = __getname();
fs/ntfs3/inode.c:	new_de = __getname();
fs/ntfs3/inode.c:	de = __getname();
fs/ntfs3/inode.c:	de = __getname();
fs/ntfs3/namei.c:	struct cpu_str *uni = __getname();
fs/ntfs3/namei.c:	de = __getname();
fs/ntfs3/namei.c:	struct cpu_str *uni = __getname();
fs/ntfs3/namei.c:	uni = __getname();
fs/ntfs3/namei.c:	uni1 = __getname();
fs/vboxsf/utils.c: * Returns a shfl_string allocated through __getname (must be freed using
fs/vboxsf/utils.c:	buf = __getname();
fs/vboxsf/utils.c:		shfl_path = __getname();

> 
> > Using f2fs_kmem_cache_alloc is able to inject malloc error.
> > But here is a trace event, is it ok to inject error in a trace path?
> 
> Yes, the fail path handling is very simple, so it's fine to leave it
> as it is.
> 
> Reviewed-by: Chao Yu <chao@kernel.org>

What is this for?

> 
> Thanks,
> 
> > 
> > > 
> > > >    	if (!buf)
> > > >    		return;
> > > >    	path = dentry_path_raw(file_dentry(iocb->ki_filp), buf, PATH_MAX);
> > > > @@ -4374,7 +4374,7 @@ static void f2fs_trace_rw_file_path(struct kiocb *iocb, size_t count, int rw)
> > > >    		trace_f2fs_dataread_start(inode, iocb->ki_pos, count,
> > > >    				current->pid, path, current->comm);
> > > >    free_buf:
> > > > -	kfree(buf);
> > > > +	__putname(buf);
> > > 
> > > kmem_cache_free(names_cachep, buf);
> > > 
> > > Thanks,
> > > 
> > > >    }
> > > >    static ssize_t f2fs_file_read_iter(struct kiocb *iocb, struct iov_iter *to)

Re: [f2fs-dev] [PATCH 1/1] f2fs: allocate trace path buffer from names_cache

[Jaegeuk Kim]

On 04/19, Jaegeuk Kim wrote:
> On 04/19, Chao Yu wrote:
> > On 2023/4/19 0:07, Jaegeuk Kim wrote:
> > > On 04/18, Chao Yu wrote:
> > > > On 2023/4/14 18:43, Wu Bo wrote:
> > > > > It would be better to use the dedicated slab to store path.
> > > > > 
> > > > > Signed-off-by: Wu Bo <bo.wu@vivo.com>
> > > > > ---
> > > > >    fs/f2fs/file.c | 4 ++--
> > > > >    1 file changed, 2 insertions(+), 2 deletions(-)
> > > > > 
> > > > > diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
> > > > > index 15dabeac4690..27137873958f 100644
> > > > > --- a/fs/f2fs/file.c
> > > > > +++ b/fs/f2fs/file.c
> > > > > @@ -4361,7 +4361,7 @@ static void f2fs_trace_rw_file_path(struct kiocb *iocb, size_t count, int rw)
> > > > >    	struct inode *inode = file_inode(iocb->ki_filp);
> > > > >    	char *buf, *path;
> > > > > -	buf = f2fs_kmalloc(F2FS_I_SB(inode), PATH_MAX, GFP_KERNEL);
> > > > > +	buf = __getname();
> > > > 
> > > > How about:
> > > > 
> > > > buf = f2fs_kmem_cache_alloc(names_cachep, GFP_KERNEL, NULL, F2FS_I_SB(inode));
> > > 
> > > This looks like a hack using names_cachep?
> > 
> > names_cachep was exported in fs.h.
> 
> I think that's for __getname() in general, which doesn't indicate you can hack.
> No one is using like that.
> 
> $ grep names_cachep fs/* -R
> fs/dcache.c:struct kmem_cache *names_cachep __read_mostly;
> fs/dcache.c:EXPORT_SYMBOL(names_cachep);
> fs/dcache.c:	names_cachep = kmem_cache_create_usercopy("names_cache", PATH_MAX, 0,
> 
> $ grep __getname fs/* -R
> fs/ceph/mds_client.c:	path = __getname();
> fs/cifs/cifsproto.h:	return __getname();
> fs/dcache.c:/* SLAB cache for __getname() consumers */
> fs/d_path.c:	char *page = __getname();
> fs/exfat/dir.c:	nb->lfn = __getname();
> fs/f2fs/file.c:	buf = __getname();
> fs/fat/dir.c:		*unicode = __getname();
> fs/fat/namei_vfat.c:	uname = __getname();
> fs/hostfs/hostfs_kern.c:	char *name = __getname();
> fs/namei.c:	result = __getname();
> fs/namei.c:	result = __getname();
> fs/ntfs3/dir.c:	name = __getname();
> fs/ntfs3/xattr.c:	buf = __getname();
> fs/ntfs3/inode.c:	new_de = __getname();
> fs/ntfs3/inode.c:	de = __getname();
> fs/ntfs3/inode.c:	de = __getname();
> fs/ntfs3/namei.c:	struct cpu_str *uni = __getname();
> fs/ntfs3/namei.c:	de = __getname();
> fs/ntfs3/namei.c:	struct cpu_str *uni = __getname();
> fs/ntfs3/namei.c:	uni = __getname();
> fs/ntfs3/namei.c:	uni1 = __getname();
> fs/vboxsf/utils.c: * Returns a shfl_string allocated through __getname (must be freed using
> fs/vboxsf/utils.c:	buf = __getname();
> fs/vboxsf/utils.c:		shfl_path = __getname();
> 
> > 
> > > Using f2fs_kmem_cache_alloc is able to inject malloc error.
> > > But here is a trace event, is it ok to inject error in a trace path?
> > 
> > Yes, the fail path handling is very simple, so it's fine to leave it
> > as it is.
> > 
> > Reviewed-by: Chao Yu <chao@kernel.org>
> 
> What is this for?
> 

If we want to keep the error injection, how about this?

Signed-off-by: Wu Bo <bo.wu@vivo.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
---
 fs/f2fs/f2fs.h | 13 +++++++++++++
 fs/f2fs/file.c |  4 ++--
 2 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 6cae94d51821..d87044516fe9 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -3347,6 +3347,19 @@ static inline void *f2fs_kmalloc(struct f2fs_sb_info *sbi,
 	return kmalloc(size, flags);
 }
 
+static inline void *f2fs_getname(struct f2fs_sb_info *sbi)
+{
+	if (time_to_inject(sbi, FAULT_KMALLOC))
+		return NULL;
+
+	return __getname();
+}
+
+static inline void f2fs_putname(char *buf)
+{
+	__putname(buf);
+}
+
 static inline void *f2fs_kzalloc(struct f2fs_sb_info *sbi,
 					size_t size, gfp_t flags)
 {
diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index 1b4411271f54..5ac53d2627d2 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -4372,7 +4372,7 @@ static void f2fs_trace_rw_file_path(struct kiocb *iocb, size_t count, int rw)
 	struct inode *inode = file_inode(iocb->ki_filp);
 	char *buf, *path;
 
-	buf = f2fs_kmalloc(F2FS_I_SB(inode), PATH_MAX, GFP_KERNEL);
+	buf = f2fs_getname(F2FS_I_SB(inode));
 	if (!buf)
 		return;
 	path = dentry_path_raw(file_dentry(iocb->ki_filp), buf, PATH_MAX);
@@ -4385,7 +4385,7 @@ static void f2fs_trace_rw_file_path(struct kiocb *iocb, size_t count, int rw)
 		trace_f2fs_dataread_start(inode, iocb->ki_pos, count,
 				current->pid, path, current->comm);
 free_buf:
-	kfree(buf);
+	f2fs_putname(buf);
 }
 
 static ssize_t f2fs_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
-- 
2.40.0.634.g4ca3ef3211-goog

Re: [f2fs-dev] [PATCH 1/1] f2fs: allocate trace path buffer from names_cache

[Chao Yu]

On 2023/4/20 3:45, Jaegeuk Kim wrote:
> On 04/19, Jaegeuk Kim wrote:
>> On 04/19, Chao Yu wrote:
>>> On 2023/4/19 0:07, Jaegeuk Kim wrote:
>>>> On 04/18, Chao Yu wrote:
>>>>> On 2023/4/14 18:43, Wu Bo wrote:
>>>>>> It would be better to use the dedicated slab to store path.
>>>>>>
>>>>>> Signed-off-by: Wu Bo <bo.wu@vivo.com>
>>>>>> ---
>>>>>>     fs/f2fs/file.c | 4 ++--
>>>>>>     1 file changed, 2 insertions(+), 2 deletions(-)
>>>>>>
>>>>>> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
>>>>>> index 15dabeac4690..27137873958f 100644
>>>>>> --- a/fs/f2fs/file.c
>>>>>> +++ b/fs/f2fs/file.c
>>>>>> @@ -4361,7 +4361,7 @@ static void f2fs_trace_rw_file_path(struct kiocb *iocb, size_t count, int rw)
>>>>>>     	struct inode *inode = file_inode(iocb->ki_filp);
>>>>>>     	char *buf, *path;
>>>>>> -	buf = f2fs_kmalloc(F2FS_I_SB(inode), PATH_MAX, GFP_KERNEL);
>>>>>> +	buf = __getname();
>>>>>
>>>>> How about:
>>>>>
>>>>> buf = f2fs_kmem_cache_alloc(names_cachep, GFP_KERNEL, NULL, F2FS_I_SB(inode));
>>>>
>>>> This looks like a hack using names_cachep?
>>>
>>> names_cachep was exported in fs.h.
>>
>> I think that's for __getname() in general, which doesn't indicate you can hack.
>> No one is using like that.
>>
>> $ grep names_cachep fs/* -R
>> fs/dcache.c:struct kmem_cache *names_cachep __read_mostly;
>> fs/dcache.c:EXPORT_SYMBOL(names_cachep);
>> fs/dcache.c:	names_cachep = kmem_cache_create_usercopy("names_cache", PATH_MAX, 0,
>>
>> $ grep __getname fs/* -R
>> fs/ceph/mds_client.c:	path = __getname();
>> fs/cifs/cifsproto.h:	return __getname();
>> fs/dcache.c:/* SLAB cache for __getname() consumers */
>> fs/d_path.c:	char *page = __getname();
>> fs/exfat/dir.c:	nb->lfn = __getname();
>> fs/f2fs/file.c:	buf = __getname();
>> fs/fat/dir.c:		*unicode = __getname();
>> fs/fat/namei_vfat.c:	uname = __getname();
>> fs/hostfs/hostfs_kern.c:	char *name = __getname();
>> fs/namei.c:	result = __getname();
>> fs/namei.c:	result = __getname();
>> fs/ntfs3/dir.c:	name = __getname();
>> fs/ntfs3/xattr.c:	buf = __getname();
>> fs/ntfs3/inode.c:	new_de = __getname();
>> fs/ntfs3/inode.c:	de = __getname();
>> fs/ntfs3/inode.c:	de = __getname();
>> fs/ntfs3/namei.c:	struct cpu_str *uni = __getname();
>> fs/ntfs3/namei.c:	de = __getname();
>> fs/ntfs3/namei.c:	struct cpu_str *uni = __getname();
>> fs/ntfs3/namei.c:	uni = __getname();
>> fs/ntfs3/namei.c:	uni1 = __getname();
>> fs/vboxsf/utils.c: * Returns a shfl_string allocated through __getname (must be freed using
>> fs/vboxsf/utils.c:	buf = __getname();
>> fs/vboxsf/utils.c:		shfl_path = __getname();
>>
>>>
>>>> Using f2fs_kmem_cache_alloc is able to inject malloc error.
>>>> But here is a trace event, is it ok to inject error in a trace path?
>>>
>>> Yes, the fail path handling is very simple, so it's fine to leave it
>>> as it is.
>>>
>>> Reviewed-by: Chao Yu <chao@kernel.org>
>>
>> What is this for?

Oh, I mean I'm okay w/ original patch, because f2fs_trace_rw_file_path()
doesn't have complicated error handling.

>>
> 
> If we want to keep the error injection, how about this?

Both original patch or below patch w/ fault injection is fine to me.

Free feel to add rvb tag of me. :)

Thanks,

> 
> Signed-off-by: Wu Bo <bo.wu@vivo.com>
> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
> ---
>   fs/f2fs/f2fs.h | 13 +++++++++++++
>   fs/f2fs/file.c |  4 ++--
>   2 files changed, 15 insertions(+), 2 deletions(-)
> 
> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> index 6cae94d51821..d87044516fe9 100644
> --- a/fs/f2fs/f2fs.h
> +++ b/fs/f2fs/f2fs.h
> @@ -3347,6 +3347,19 @@ static inline void *f2fs_kmalloc(struct f2fs_sb_info *sbi,
>   	return kmalloc(size, flags);
>   }
>   
> +static inline void *f2fs_getname(struct f2fs_sb_info *sbi)
> +{
> +	if (time_to_inject(sbi, FAULT_KMALLOC))
> +		return NULL;
> +
> +	return __getname();
> +}
> +
> +static inline void f2fs_putname(char *buf)
> +{
> +	__putname(buf);
> +}
> +
>   static inline void *f2fs_kzalloc(struct f2fs_sb_info *sbi,
>   					size_t size, gfp_t flags)
>   {
> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
> index 1b4411271f54..5ac53d2627d2 100644
> --- a/fs/f2fs/file.c
> +++ b/fs/f2fs/file.c
> @@ -4372,7 +4372,7 @@ static void f2fs_trace_rw_file_path(struct kiocb *iocb, size_t count, int rw)
>   	struct inode *inode = file_inode(iocb->ki_filp);
>   	char *buf, *path;
>   
> -	buf = f2fs_kmalloc(F2FS_I_SB(inode), PATH_MAX, GFP_KERNEL);
> +	buf = f2fs_getname(F2FS_I_SB(inode));
>   	if (!buf)
>   		return;
>   	path = dentry_path_raw(file_dentry(iocb->ki_filp), buf, PATH_MAX);
> @@ -4385,7 +4385,7 @@ static void f2fs_trace_rw_file_path(struct kiocb *iocb, size_t count, int rw)
>   		trace_f2fs_dataread_start(inode, iocb->ki_pos, count,
>   				current->pid, path, current->comm);
>   free_buf:
> -	kfree(buf);
> +	f2fs_putname(buf);
>   }
>   
>   static ssize_t f2fs_file_read_iter(struct kiocb *iocb, struct iov_iter *to)