Re: [PATCH 27/33] fuse_trace: implement inline data file IO via iomap

["Darrick J. Wong" <djwong@kernel.org>]

On Wed, Apr 29, 2026 at 07:30:43AM -0700, Darrick J. Wong wrote:
> From: Darrick J. Wong <djwong@kernel.org>
> 
> Add tracepoints for the previous patch.
> 
> Signed-off-by: "Darrick J. Wong" <djwong@kernel.org>
> ---
>  fs/fuse/fuse_trace.h |   45 +++++++++++++++++++++++++++++++++++++++++++++
>  fs/fuse/fuse_iomap.c |    7 +++++++
>  2 files changed, 52 insertions(+)
> 
> 
> diff --git a/fs/fuse/fuse_trace.h b/fs/fuse/fuse_trace.h
> index 0e4be645802055..d3352e75fa6bdf 100644
> --- a/fs/fuse/fuse_trace.h
> +++ b/fs/fuse/fuse_trace.h
> @@ -230,6 +230,7 @@ DEFINE_FUSE_BACKING_EVENT(fuse_backing_close);
>  #if IS_ENABLED(CONFIG_FUSE_IOMAP)
>  struct iomap_writepage_ctx;
>  struct iomap_ioend;
> +struct iomap;
>  
>  /* tracepoint boilerplate so we don't have to keep doing this */
>  #define FUSE_IOMAP_OPFLAGS_FIELD \
> @@ -1079,6 +1080,50 @@ TRACE_EVENT(fuse_iomap_dev_inval,
>  		  __entry->offset,
>  		  __entry->length)
>  );
> +
> +DECLARE_EVENT_CLASS(fuse_iomap_inline_class,
> +	TP_PROTO(const struct inode *inode, loff_t pos, uint64_t count,
> +		 const struct iomap *map),
> +	TP_ARGS(inode, pos, count, map),
> +
> +	TP_STRUCT__entry(
> +		FUSE_IO_RANGE_FIELDS()
> +		FUSE_IOMAP_MAP_FIELDS(map)
> +		__field(bool,			has_buf)
> +		__field(uint64_t,		validity_cookie)
> +	),
> +
> +	TP_fast_assign(
> +		FUSE_INODE_ASSIGN(inode, fi, fm);
> +		__entry->offset		=	pos;
> +		__entry->length		=	count;
> +
> +		__entry->mapdev		=	FUSE_IOMAP_DEV_NULL;
> +		__entry->mapaddr	=	map->addr;
> +		__entry->mapoffset	=	map->offset;
> +		__entry->maplength	=	map->length;
> +		__entry->maptype	=	map->type;
> +		__entry->mapflags	=	map->flags;
> +
> +		__entry->has_buf	=	map->inline_data != NULL;
> +		__entry->validity_cookie=	map->validity_cookie;
> +	),
> +
> +	TP_printk(FUSE_IO_RANGE_FMT() FUSE_IOMAP_MAP_FMT() " has_buf? %d cookie 0x%llx",
> +		  FUSE_IO_RANGE_PRINTK_ARGS(),
> +		  FUSE_IOMAP_MAP_PRINTK_ARGS(map),

Codex complains that we're using the flags/type decoding strings for
struct fuse_iomap_io on a struct iomap object so the decoding won't be
correct.  We already know the type and the flags aren't that interesting
for an inline mapping so let's just opencode the map offset/range.

--D

> +		  __entry->has_buf,
> +		  __entry->validity_cookie)
> +);
> +#define DEFINE_FUSE_IOMAP_INLINE_EVENT(name)	\
> +DEFINE_EVENT(fuse_iomap_inline_class, name,	\
> +	TP_PROTO(const struct inode *inode, loff_t pos, uint64_t count, \
> +		 const struct iomap *map), \
> +	TP_ARGS(inode, pos, count, map))
> +DEFINE_FUSE_IOMAP_INLINE_EVENT(fuse_iomap_inline_read);
> +DEFINE_FUSE_IOMAP_INLINE_EVENT(fuse_iomap_inline_write);
> +DEFINE_FUSE_IOMAP_INLINE_EVENT(fuse_iomap_set_inline_iomap);
> +DEFINE_FUSE_IOMAP_INLINE_EVENT(fuse_iomap_set_inline_srcmap);
>  #endif /* CONFIG_FUSE_IOMAP */
>  
>  #endif /* _TRACE_FUSE_H */
> diff --git a/fs/fuse/fuse_iomap.c b/fs/fuse/fuse_iomap.c
> index b9531ad5ab5180..8be8e49605bb85 100644
> --- a/fs/fuse/fuse_iomap.c
> +++ b/fs/fuse/fuse_iomap.c
> @@ -435,6 +435,8 @@ static int fuse_iomap_inline_read(struct inode *inode, loff_t pos,
>  		return -EFSCORRUPTED;
>  	}
>  
> +	trace_fuse_iomap_inline_read(inode, pos, count, iomap);
> +
>  	args.opcode = FUSE_READ;
>  	args.nodeid = fi->nodeid;
>  	args.in_numargs = 1;
> @@ -482,6 +484,8 @@ static int fuse_iomap_inline_write(struct inode *inode, loff_t pos,
>  	if (BAD_DATA(!iomap_inline_data_valid(iomap)))
>  		return -EFSCORRUPTED;
>  
> +	trace_fuse_iomap_inline_write(inode, pos, count, iomap);
> +
>  	args.opcode = FUSE_WRITE;
>  	args.nodeid = fi->nodeid;
>  	args.in_numargs = 2;
> @@ -545,6 +549,9 @@ static int fuse_iomap_set_inline(struct inode *inode, unsigned opflags,
>  			return err;
>  	}
>  
> +	trace_fuse_iomap_set_inline_iomap(inode, pos, count, iomap);
> +	trace_fuse_iomap_set_inline_srcmap(inode, pos, count, srcmap);
> +
>  	return 0;
>  }
>  
> 
>