linux-kernel - Re: [PATCH v2 13/13] ext4: add two trace points for moving extents

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Message-ID: <kkecvhazplnbbvv2omtwae6jckon3onaym5gbxp7bndnoqr5eq@xow35t5dhhph>
Date: Wed, 8 Oct 2025 14:54:58 +0200
From: Jan Kara <jack@...e.cz>
To: Zhang Yi <yi.zhang@...weicloud.com>
Cc: linux-ext4@...r.kernel.org, linux-fsdevel@...r.kernel.org, 
	linux-kernel@...r.kernel.org, tytso@....edu, adilger.kernel@...ger.ca, jack@...e.cz, 
	yi.zhang@...wei.com, libaokun1@...wei.com, yukuai3@...wei.com, yangerkun@...wei.com
Subject: Re: [PATCH v2 13/13] ext4: add two trace points for moving extents

On Thu 25-09-25 17:26:09, Zhang Yi wrote:
> From: Zhang Yi <yi.zhang@...wei.com>
> 
> To facilitate tracking the length, type, and outcome of the move extent,
> add a trace point at both the entry and exit of mext_move_extent().
> 
> Signed-off-by: Zhang Yi <yi.zhang@...wei.com>

Looks good. Feel free to add:

Reviewed-by: Jan Kara <jack@...e.cz>

								Honza

> ---
>  fs/ext4/move_extent.c       | 14 ++++++-
>  include/trace/events/ext4.h | 74 +++++++++++++++++++++++++++++++++++++
>  2 files changed, 86 insertions(+), 2 deletions(-)
> 
> diff --git a/fs/ext4/move_extent.c b/fs/ext4/move_extent.c
> index 0fa97c207274..53a8b9caeeda 100644
> --- a/fs/ext4/move_extent.c
> +++ b/fs/ext4/move_extent.c
> @@ -13,6 +13,8 @@
>  #include "ext4.h"
>  #include "ext4_extents.h"
>  
> +#include <trace/events/ext4.h>
> +
>  struct mext_data {
>  	struct inode *orig_inode;	/* Origin file inode */
>  	struct inode *donor_inode;	/* Donor file inode */
> @@ -311,10 +313,14 @@ static int mext_move_extent(struct mext_data *mext, u64 *m_len)
>  	int ret, ret2;
>  
>  	*m_len = 0;
> +	trace_ext4_move_extent_enter(orig_inode, orig_map, donor_inode,
> +				     mext->donor_lblk);
>  	credits = ext4_chunk_trans_extent(orig_inode, 0) * 2;
>  	handle = ext4_journal_start(orig_inode, EXT4_HT_MOVE_EXTENTS, credits);
> -	if (IS_ERR(handle))
> -		return PTR_ERR(handle);
> +	if (IS_ERR(handle)) {
> +		ret = PTR_ERR(handle);
> +		goto out;
> +	}
>  
>  	ret = mext_move_begin(mext, folio, &move_type);
>  	if (ret)
> @@ -372,6 +378,10 @@ static int mext_move_extent(struct mext_data *mext, u64 *m_len)
>  	mext_folio_double_unlock(folio);
>  stop_handle:
>  	ext4_journal_stop(handle);
> +out:
> +	trace_ext4_move_extent_exit(orig_inode, orig_map->m_lblk, donor_inode,
> +				    mext->donor_lblk, orig_map->m_len, *m_len,
> +				    move_type, ret);
>  	return ret;
>  
>  repair_branches:
> diff --git a/include/trace/events/ext4.h b/include/trace/events/ext4.h
> index 6a0754d38acf..a05bdd48e16e 100644
> --- a/include/trace/events/ext4.h
> +++ b/include/trace/events/ext4.h
> @@ -3016,6 +3016,80 @@ TRACE_EVENT(ext4_update_sb,
>  		  __entry->fsblk, __entry->flags)
>  );
>  
> +TRACE_EVENT(ext4_move_extent_enter,
> +	TP_PROTO(struct inode *orig_inode, struct ext4_map_blocks *orig_map,
> +		 struct inode *donor_inode, ext4_lblk_t donor_lblk),
> +
> +	TP_ARGS(orig_inode, orig_map, donor_inode, donor_lblk),
> +
> +	TP_STRUCT__entry(
> +		__field(dev_t, dev)
> +		__field(ino_t, orig_ino)
> +		__field(ext4_lblk_t, orig_lblk)
> +		__field(unsigned int, orig_flags)
> +		__field(ino_t, donor_ino)
> +		__field(ext4_lblk_t, donor_lblk)
> +		__field(unsigned int, len)
> +	),
> +
> +	TP_fast_assign(
> +		__entry->dev		= orig_inode->i_sb->s_dev;
> +		__entry->orig_ino	= orig_inode->i_ino;
> +		__entry->orig_lblk	= orig_map->m_lblk;
> +		__entry->orig_flags	= orig_map->m_flags;
> +		__entry->donor_ino	= donor_inode->i_ino;
> +		__entry->donor_lblk	= donor_lblk;
> +		__entry->len		= orig_map->m_len;
> +	),
> +
> +	TP_printk("dev %d,%d origin ino %lu lblk %u flags %s donor ino %lu lblk %u len %u",
> +		  MAJOR(__entry->dev), MINOR(__entry->dev),
> +		  (unsigned long) __entry->orig_ino,  __entry->orig_lblk,
> +		  show_mflags(__entry->orig_flags),
> +		  (unsigned long) __entry->donor_ino,  __entry->donor_lblk,
> +		  __entry->len)
> +);
> +
> +TRACE_EVENT(ext4_move_extent_exit,
> +	TP_PROTO(struct inode *orig_inode, ext4_lblk_t orig_lblk,
> +		 struct inode *donor_inode, ext4_lblk_t donor_lblk,
> +		 unsigned int m_len, u64 move_len, int move_type, int ret),
> +
> +	TP_ARGS(orig_inode, orig_lblk, donor_inode, donor_lblk, m_len,
> +		move_len, move_type, ret),
> +
> +	TP_STRUCT__entry(
> +		__field(dev_t, dev)
> +		__field(ino_t, orig_ino)
> +		__field(ext4_lblk_t, orig_lblk)
> +		__field(ino_t, donor_ino)
> +		__field(ext4_lblk_t, donor_lblk)
> +		__field(unsigned int, m_len)
> +		__field(u64, move_len)
> +		__field(int, move_type)
> +		__field(int, ret)
> +	),
> +
> +	TP_fast_assign(
> +		__entry->dev		= orig_inode->i_sb->s_dev;
> +		__entry->orig_ino	= orig_inode->i_ino;
> +		__entry->orig_lblk	= orig_lblk;
> +		__entry->donor_ino	= donor_inode->i_ino;
> +		__entry->donor_lblk	= donor_lblk;
> +		__entry->m_len		= m_len;
> +		__entry->move_len	= move_len;
> +		__entry->move_type	= move_type;
> +		__entry->ret		= ret;
> +	),
> +
> +	TP_printk("dev %d,%d origin ino %lu lblk %u donor ino %lu lblk %u m_len %u, move_len %llu type %d ret %d",
> +		  MAJOR(__entry->dev), MINOR(__entry->dev),
> +		  (unsigned long) __entry->orig_ino,  __entry->orig_lblk,
> +		  (unsigned long) __entry->donor_ino,  __entry->donor_lblk,
> +		  __entry->m_len, __entry->move_len, __entry->move_type,
> +		  __entry->ret)
> +);
> +
>  #endif /* _TRACE_EXT4_H */
>  
>  /* This part must be outside protection */
> -- 
> 2.46.1
> 
-- 
Jan Kara <jack@...e.com>
SUSE Labs, CR