Re: [PATCH 2/3] f2fs: trace checkpoint reason in fsync()

[Jaegeuk Kim]

On 11/05, Chao Yu wrote:
> From: Chao Yu <yuchao0@xxxxxxxxxx>
> 
> This patch slightly changes need_do_checkpoint to return the detail
> info that indicates why we need do checkpoint, then caller could print
> it with trace message.
> 
> Signed-off-by: Chao Yu <yuchao0@xxxxxxxxxx>
> ---
>  fs/f2fs/file.c              | 34 ++++++++++++++++++----------------
>  include/trace/events/f2fs.h | 12 ++++++------
>  2 files changed, 24 insertions(+), 22 deletions(-)
> 
> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
> index cee0f36ba9a1..d9d8b1c372f8 100644
> --- a/fs/f2fs/file.c
> +++ b/fs/f2fs/file.c
> @@ -141,27 +141,29 @@ static int get_parent_ino(struct inode *inode, nid_t *pino)
>  	return 1;
>  }
>  
> -static inline bool need_do_checkpoint(struct inode *inode)
> +static inline int need_do_checkpoint(struct inode *inode)
>  {
>  	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
> -	bool need_cp = false;
> +	int cp_reason = 0;
>  
> -	if (!S_ISREG(inode->i_mode) || inode->i_nlink != 1)
> -		need_cp = true;
> +	if (!S_ISREG(inode->i_mode))
> +		cp_reason = 1;
> +	else if (inode->i_nlink != 1)
> +		cp_reason = 2;
>  	else if (is_sbi_flag_set(sbi, SBI_NEED_CP))
> -		need_cp = true;
> +		cp_reason = 3;
>  	else if (file_wrong_pino(inode))
> -		need_cp = true;
> +		cp_reason = 4;
>  	else if (!space_for_roll_forward(sbi))
> -		need_cp = true;
> +		cp_reason = 5;
>  	else if (!is_checkpointed_node(sbi, F2FS_I(inode)->i_pino))
> -		need_cp = true;
> +		cp_reason = 6;
>  	else if (test_opt(sbi, FASTBOOT))
> -		need_cp = true;
> +		cp_reason = 7;
>  	else if (sbi->active_logs == 2)
> -		need_cp = true;
> +		cp_reason = 8;

We need to make the numbers by enum so that we could interpret them in tracepoint
below.

Thanks,

>  
> -	return need_cp;
> +	return cp_reason;
>  }
>  
>  static bool need_inode_page_update(struct f2fs_sb_info *sbi, nid_t ino)
> @@ -196,7 +198,7 @@ static int f2fs_do_sync_file(struct file *file, loff_t start, loff_t end,
>  	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
>  	nid_t ino = inode->i_ino;
>  	int ret = 0;
> -	bool need_cp = false;
> +	bool cp_reason = 0;
>  	struct writeback_control wbc = {
>  		.sync_mode = WB_SYNC_ALL,
>  		.nr_to_write = LONG_MAX,
> @@ -215,7 +217,7 @@ static int f2fs_do_sync_file(struct file *file, loff_t start, loff_t end,
>  	clear_inode_flag(inode, FI_NEED_IPU);
>  
>  	if (ret) {
> -		trace_f2fs_sync_file_exit(inode, need_cp, datasync, ret);
> +		trace_f2fs_sync_file_exit(inode, cp_reason, datasync, ret);
>  		return ret;
>  	}
>  
> @@ -246,10 +248,10 @@ static int f2fs_do_sync_file(struct file *file, loff_t start, loff_t end,
>  	 * sudden-power-off.
>  	 */
>  	down_read(&F2FS_I(inode)->i_sem);
> -	need_cp = need_do_checkpoint(inode);
> +	cp_reason = need_do_checkpoint(inode);
>  	up_read(&F2FS_I(inode)->i_sem);
>  
> -	if (need_cp) {
> +	if (cp_reason) {
>  		/* all the dirty node pages should be flushed for POR */
>  		ret = f2fs_sync_fs(inode->i_sb, 1);
>  
> @@ -306,7 +308,7 @@ static int f2fs_do_sync_file(struct file *file, loff_t start, loff_t end,
>  	}
>  	f2fs_update_time(sbi, REQ_TIME);
>  out:
> -	trace_f2fs_sync_file_exit(inode, need_cp, datasync, ret);
> +	trace_f2fs_sync_file_exit(inode, cp_reason, datasync, ret);
>  	f2fs_trace_ios(NULL, 1);
>  	return ret;
>  }
> diff --git a/include/trace/events/f2fs.h b/include/trace/events/f2fs.h
> index 009745564214..f1a317e6db79 100644
> --- a/include/trace/events/f2fs.h
> +++ b/include/trace/events/f2fs.h
> @@ -210,14 +210,14 @@ DEFINE_EVENT(f2fs__inode, f2fs_sync_file_enter,
>  
>  TRACE_EVENT(f2fs_sync_file_exit,
>  
> -	TP_PROTO(struct inode *inode, int need_cp, int datasync, int ret),
> +	TP_PROTO(struct inode *inode, int cp_reason, int datasync, int ret),
>  
> -	TP_ARGS(inode, need_cp, datasync, ret),
> +	TP_ARGS(inode, cp_reason, datasync, ret),
>  
>  	TP_STRUCT__entry(
>  		__field(dev_t,	dev)
>  		__field(ino_t,	ino)
> -		__field(int,	need_cp)
> +		__field(int,	cp_reason)
>  		__field(int,	datasync)
>  		__field(int,	ret)
>  	),
> @@ -225,15 +225,15 @@ TRACE_EVENT(f2fs_sync_file_exit,
>  	TP_fast_assign(
>  		__entry->dev		= inode->i_sb->s_dev;
>  		__entry->ino		= inode->i_ino;
> -		__entry->need_cp	= need_cp;
> +		__entry->cp_reason	= cp_reason;
>  		__entry->datasync	= datasync;
>  		__entry->ret		= ret;
>  	),
>  
> -	TP_printk("dev = (%d,%d), ino = %lu, checkpoint is %s, "
> +	TP_printk("dev = (%d,%d), ino = %lu, cp_reason:%d, "
>  		"datasync = %d, ret = %d",
>  		show_dev_ino(__entry),
> -		__entry->need_cp ? "needed" : "not needed",
> +		__entry->cp_reason,
>  		__entry->datasync,
>  		__entry->ret)
>  );
> -- 
> 2.14.1.145.gb3622a4ee