Re: [f2fs-dev] [PATCH v2] f2fs: introduce data read/write showing path info

[Chao Yu <chao@kernel.org>]

On 2022/3/22 8:13, Jaegeuk Kim wrote:
> This was used in Android for a long time. Let's upstream it.
> 
> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
> ---
> 
>   Change log from v1:
>    - remove unnecessary path lookup
> 
>   fs/f2fs/file.c              | 48 ++++++++++++++++---
>   include/trace/events/f2fs.h | 94 +++++++++++++++++++++++++++++++++++++
>   2 files changed, 135 insertions(+), 7 deletions(-)
> 
> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
> index 68ddf4c7ca64..19bc916c1eb7 100644
> --- a/fs/f2fs/file.c
> +++ b/fs/f2fs/file.c
> @@ -4329,17 +4329,34 @@ static ssize_t f2fs_dio_read_iter(struct kiocb *iocb, struct iov_iter *to)
>   static ssize_t f2fs_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
>   {
>   	struct inode *inode = file_inode(iocb->ki_filp);
> +	const loff_t pos = iocb->ki_pos;
>   	ssize_t ret;
>   
>   	if (!f2fs_is_compress_backend_ready(inode))
>   		return -EOPNOTSUPP;
>   
> -	if (f2fs_should_use_dio(inode, iocb, to))
> -		return f2fs_dio_read_iter(iocb, to);
> +	if (trace_f2fs_dataread_start_enabled()) {
> +		char *path, *p = kmalloc(PATH_MAX, GFP_KERNEL);

f2fs_kmalloc();

> +		if (!p)
> +			goto skip_read_trace;
> +
> +		path = dentry_path_raw(file_dentry(iocb->ki_filp), p, PATH_MAX);
> +		if (IS_ERR(path))

kfree();

> +			goto skip_read_trace;
>   
> -	ret = filemap_read(iocb, to, 0);
> -	if (ret > 0)
> -		f2fs_update_iostat(F2FS_I_SB(inode), APP_BUFFERED_READ_IO, ret);
> +		trace_f2fs_dataread_start(inode, pos, iov_iter_count(to),
> +					current->pid, path, current->comm);
> +		kfree(p);
> +	}
> +skip_read_trace:
> +	if (f2fs_should_use_dio(inode, iocb, to)) {
> +		ret = f2fs_dio_read_iter(iocb, to);
> +	} else {
> +		ret = filemap_read(iocb, to, 0);
> +		if (ret > 0)
> +			f2fs_update_iostat(F2FS_I_SB(inode), APP_BUFFERED_READ_IO, ret);
> +	}

if (trace_f2fs_dataread_end_enabled())

Thanks,

> +	trace_f2fs_dataread_end(inode, pos, ret);
>   	return ret;
>   }
>   
> @@ -4637,14 +4654,31 @@ static ssize_t f2fs_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
>   	/* Possibly preallocate the blocks for the write. */
>   	target_size = iocb->ki_pos + iov_iter_count(from);
>   	preallocated = f2fs_preallocate_blocks(iocb, from, dio);
> -	if (preallocated < 0)
> +	if (preallocated < 0) {
>   		ret = preallocated;
> -	else
> +	} else {
> +		if (trace_f2fs_datawrite_start_enabled()) {
> +			char *path, *p = kmalloc(PATH_MAX, GFP_KERNEL);

f2fs_kmalloc()

> +			if (!p)
> +				goto skip_write_trace;
> +			path = dentry_path_raw(file_dentry(iocb->ki_filp),
> +								p, PATH_MAX);
> +			if (IS_ERR(path))

kfree();

> +				goto skip_write_trace;
> +			trace_f2fs_datawrite_start(inode, orig_pos, orig_count,
> +					current->pid, path, current->comm);
> +			kfree(p);
> +		}
> +skip_write_trace:
>   		/* Do the actual write. */
>   		ret = dio ?
>   			f2fs_dio_write_iter(iocb, from, &may_need_sync):
>   			f2fs_buffered_write_iter(iocb, from);
>   
> +		if (trace_f2fs_datawrite_end_enabled())
> +			trace_f2fs_datawrite_end(inode, orig_pos, ret);
> +	}
> +
>   	/* Don't leave any preallocated blocks around past i_size. */
>   	if (preallocated && i_size_read(inode) < target_size) {
>   		f2fs_down_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
> diff --git a/include/trace/events/f2fs.h b/include/trace/events/f2fs.h
> index f701bb23f83c..11f6b7147be2 100644
> --- a/include/trace/events/f2fs.h
> +++ b/include/trace/events/f2fs.h
> @@ -2068,6 +2068,100 @@ TRACE_EVENT(f2fs_fiemap,
>   		__entry->ret)
>   );
>   
> +DECLARE_EVENT_CLASS(f2fs__rw_start,
> +
> +	TP_PROTO(struct inode *inode, loff_t offset, int bytes,
> +			pid_t pid, char *pathname, char *command),
> +
> +	TP_ARGS(inode, offset, bytes, pid, pathname, command),
> +
> +	TP_STRUCT__entry(
> +		__string(pathbuf, pathname)
> +		__field(loff_t, offset)
> +		__field(int, bytes)
> +		__field(loff_t, i_size)
> +		__string(cmdline, command)
> +		__field(pid_t, pid)
> +		__field(ino_t, ino)
> +	),
> +
> +	TP_fast_assign(
> +		/*
> +		 * Replace the spaces in filenames and cmdlines
> +		 * because this screws up the tooling that parses
> +		 * the traces.
> +		 */
> +		__assign_str(pathbuf, pathname);
> +		(void)strreplace(__get_str(pathbuf), ' ', '_');
> +		__entry->offset = offset;
> +		__entry->bytes = bytes;
> +		__entry->i_size = i_size_read(inode);
> +		__assign_str(cmdline, command);
> +		(void)strreplace(__get_str(cmdline), ' ', '_');
> +		__entry->pid = pid;
> +		__entry->ino = inode->i_ino;
> +	),
> +
> +	TP_printk("entry_name %s, offset %llu, bytes %d, cmdline %s,"
> +		" pid %d, i_size %llu, ino %lu",
> +		__get_str(pathbuf), __entry->offset, __entry->bytes,
> +		__get_str(cmdline), __entry->pid, __entry->i_size,
> +		(unsigned long) __entry->ino)
> +);
> +
> +DECLARE_EVENT_CLASS(f2fs__rw_end,
> +
> +	TP_PROTO(struct inode *inode, loff_t offset, int bytes),
> +
> +	TP_ARGS(inode, offset, bytes),
> +
> +	TP_STRUCT__entry(
> +		__field(ino_t,	ino)
> +		__field(loff_t,	offset)
> +		__field(int,	bytes)
> +	),
> +
> +	TP_fast_assign(
> +		__entry->ino		= inode->i_ino;
> +		__entry->offset		= offset;
> +		__entry->bytes		= bytes;
> +	),
> +
> +	TP_printk("ino %lu, offset %llu, bytes %d",
> +		(unsigned long) __entry->ino,
> +		__entry->offset, __entry->bytes)
> +);
> +
> +DEFINE_EVENT(f2fs__rw_start, f2fs_dataread_start,
> +
> +	TP_PROTO(struct inode *inode, loff_t offset, int bytes,
> +		pid_t pid, char *pathname, char *command),
> +
> +	TP_ARGS(inode, offset, bytes, pid, pathname, command)
> +);
> +
> +DEFINE_EVENT(f2fs__rw_end, f2fs_dataread_end,
> +
> +	TP_PROTO(struct inode *inode, loff_t offset, int bytes),
> +
> +	TP_ARGS(inode, offset, bytes)
> +);
> +
> +DEFINE_EVENT(f2fs__rw_start, f2fs_datawrite_start,
> +
> +	TP_PROTO(struct inode *inode, loff_t offset, int bytes,
> +		pid_t pid, char *pathname, char *command),
> +
> +	TP_ARGS(inode, offset, bytes, pid, pathname, command)
> +);
> +
> +DEFINE_EVENT(f2fs__rw_end, f2fs_datawrite_end,
> +
> +	TP_PROTO(struct inode *inode, loff_t offset, int bytes),
> +
> +	TP_ARGS(inode, offset, bytes)
> +);
> +
>   #endif /* _TRACE_F2FS_H */
>   
>    /* This part must be outside protection */