Re: [PATCH 2/5] fuse: add STATX request

[Bernd Schubert <bernd.schubert@xxxxxxxxxxx>]

On 8/10/23 12:54, Miklos Szeredi wrote:
> Use the same structure as statx.

Wouldn't it be easier to just include struct statx? Or is there an issue 
with __u32, etc? If so, just a sufficiently large array could be used 
and statx values just mem-copied in/out?

> Signed-off-by: Miklos Szeredi <mszeredi@xxxxxxxxxx>
> ---
>   include/uapi/linux/fuse.h | 56 ++++++++++++++++++++++++++++++++++++++-
>   1 file changed, 55 insertions(+), 1 deletion(-)
>
> diff --git a/include/uapi/linux/fuse.h b/include/uapi/linux/fuse.h
> index b3fcab13fcd3..fe700b91b33b 100644
> --- a/include/uapi/linux/fuse.h
> +++ b/include/uapi/linux/fuse.h
> @@ -207,6 +207,9 @@
>    *  - add FUSE_EXT_GROUPS
>    *  - add FUSE_CREATE_SUPP_GROUP
>    *  - add FUSE_HAS_EXPIRE_ONLY
> + *
> + *  7.39
> + *  - add FUSE_STATX and related structures
>    */
>   
>   #ifndef _LINUX_FUSE_H
> @@ -242,7 +245,7 @@
>   #define FUSE_KERNEL_VERSION 7
>   
>   /** Minor version number of this interface */
> -#define FUSE_KERNEL_MINOR_VERSION 38
> +#define FUSE_KERNEL_MINOR_VERSION 39
>   
>   /** The node ID of the root inode */
>   #define FUSE_ROOT_ID 1
> @@ -269,6 +272,40 @@ struct fuse_attr {
>   	uint32_t	flags;
>   };
>   
> +/*
> + * The following structures are bit-for-bit compatible with the statx(2) ABI in
> + * Linux.
> + */
> +struct fuse_sx_time {
> +	int64_t		tv_sec;
> +	uint32_t	tv_nsec;
> +	int32_t		__reserved;
> +};
> +
> +struct fuse_statx {
> +	uint32_t	mask;
> +	uint32_t	blksize;
> +	uint64_t	attributes;
> +	uint32_t	nlink;
> +	uint32_t	uid;
> +	uint32_t	gid;
> +	uint16_t	mode;
> +	uint16_t	__spare0[1];
> +	uint64_t	ino;
> +	uint64_t	size;
> +	uint64_t	blocks;
> +	uint64_t	attributes_mask;
> +	struct fuse_sx_time	atime;
> +	struct fuse_sx_time	btime;
> +	struct fuse_sx_time	ctime;
> +	struct fuse_sx_time	mtime;
> +	uint32_t	rdev_major;
> +	uint32_t	rdev_minor;
> +	uint32_t	dev_major;
> +	uint32_t	dev_minor;
> +	uint64_t	__spare2[14];
> +};

Looks like some recent values are missing?

	/* 0x90 */
	__u64	stx_mnt_id;
	__u32	stx_dio_mem_align;	/* Memory buffer alignment for direct I/O */
	__u32	stx_dio_offset_align;	/* File offset alignment for direct I/O */
	/* 0xa0 */
	__u64	__spare3[12];	/* Spare space for future expansion */
	/* 0x100 */

Which is basically why my personal preference would be not to do have a 
copy of the struct - there is maintenance overhead.


> +
>   struct fuse_kstatfs {
>   	uint64_t	blocks;
>   	uint64_t	bfree;
> @@ -575,6 +612,7 @@ enum fuse_opcode {
>   	FUSE_REMOVEMAPPING	= 49,
>   	FUSE_SYNCFS		= 50,
>   	FUSE_TMPFILE		= 51,
> +	FUSE_STATX		= 52,
>   
>   	/* CUSE specific operations */
>   	CUSE_INIT		= 4096,
> @@ -639,6 +677,22 @@ struct fuse_attr_out {
>   	struct fuse_attr attr;
>   };
>   
> +struct fuse_statx_in {
> +	uint32_t	getattr_flags;
> +	uint32_t	reserved;
> +	uint64_t	fh;
> +	uint32_t	sx_flags;
> +	uint32_t	sx_mask;
> +};
> +
> +struct fuse_statx_out {
> +	uint64_t	attr_valid;	/* Cache timeout for the attributes */
> +	uint32_t	attr_valid_nsec;
> +	uint32_t	flags;
> +	uint64_t	spare[2];
> +	struct fuse_statx stat;
> +};
> +
>   #define FUSE_COMPAT_MKNOD_IN_SIZE 8
>   
>   struct fuse_mknod_in {


Thanks,
Bernd