Re: [PATCHv12 01/12] fs: add write stream information to statx

Christian Brauner
2024-12-09T12:47:12Z

On Fri, Dec 06, 2024 at 02:17:50PM -0800, Keith Busch wrote:
> From: Keith Busch <kbusch@kernel.org>
>
> Add new statx field to report the maximum number of write streams
> supported and the granularity for them.
>
> Signed-off-by: Keith Busch <kbusch@kernel.org>
> [hch: rename hint to stream, add granularity]
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
> fs/stat.c | 2 ++
> include/linux/stat.h | 2 ++
> include/uapi/linux/stat.h | 7 +++++--
> 3 files changed, 9 insertions(+), 2 deletions(-)
>
> diff --git a/fs/stat.c b/fs/stat.c
> index 0870e969a8a0b..00e4598b1ff25 100644
> --- a/fs/stat.c
> +++ b/fs/stat.c
> @@ -729,6 +729,8 @@ cp_statx(const struct kstat *stat, struct statx __user *buffer)
> tmp.stx_atomic_write_unit_min = stat->atomic_write_unit_min;
> tmp.stx_atomic_write_unit_max = stat->atomic_write_unit_max;
> tmp.stx_atomic_write_segments_max = stat->atomic_write_segments_max;
> + tmp.stx_write_stream_granularity = stat->write_stream_granularity;
> + tmp.stx_write_stream_max = stat->write_stream_max;
>
> return copy_to_user(buffer, &tmp, sizeof(tmp)) ? -EFAULT : 0;
> }
> diff --git a/include/linux/stat.h b/include/linux/stat.h
> index 3d900c86981c5..36d4dfb291abd 100644
> --- a/include/linux/stat.h
> +++ b/include/linux/stat.h
> @@ -57,6 +57,8 @@ struct kstat {
> u32 atomic_write_unit_min;
> u32 atomic_write_unit_max;
> u32 atomic_write_segments_max;
> + u32 write_stream_granularity;
> + u16 write_stream_max;
> };
>
> /* These definitions are internal to the kernel for now. Mainly used by nfsd. */
> diff --git a/include/uapi/linux/stat.h b/include/uapi/linux/stat.h
> index 887a252864416..547c62a1a3a7c 100644
> --- a/include/uapi/linux/stat.h
> +++ b/include/uapi/linux/stat.h
> @@ -132,9 +132,11 @@ struct statx {
> __u32 stx_atomic_write_unit_max; /* Max atomic write unit in bytes */
> /* 0xb0 */
> __u32 stx_atomic_write_segments_max; /* Max atomic write segment count */
> - __u32 __spare1[1];
> + __u32 stx_write_stream_granularity;
> /* 0xb8 */
> - __u64 __spare3[9]; /* Spare space for future expansion */
> + __u16 stx_write_stream_max;
> + __u16 __sparse2[3];
> + __u64 __spare3[8]; /* Spare space for future expansion */
> /* 0x100 */
> };

Once you're ready to merge, let me know so I can give you a stable
branch with the fs changes.

>
> @@ -164,6 +166,7 @@ struct statx {
> #define STATX_MNT_ID_UNIQUE 0x00004000U /* Want/got extended stx_mount_id */
> #define STATX_SUBVOL 0x00008000U /* Want/got stx_subvol */
> #define STATX_WRITE_ATOMIC 0x00010000U /* Want/got atomic_write_* fields */
> +#define STATX_WRITE_STREAM 0x00020000U /* Want/got write_stream_* */
>
> #define STATX__RESERVED 0x80000000U /* Reserved for future struct statx expansion */
>
> --
> 2.43.5
>

On Fri, Dec 06, 2024 at 02:17:51PM -0800, Keith Busch wrote:
> From: Christoph Hellwig <hch@lst.de>
>
> Prepare for io_uring passthrough of write streams. The write stream
> field in the kiocb structure fits into an existing 2-byte hole, so its
> size is not changed.
>
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> Signed-off-by: Keith Busch <kbusch@kernel.org>
> ---
> include/linux/fs.h | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/include/linux/fs.h b/include/linux/fs.h
> index 2cc3d45da7b01..26940c451f319 100644
> --- a/include/linux/fs.h
> +++ b/include/linux/fs.h
> @@ -373,6 +373,7 @@ struct kiocb {
> void *private;
> int ki_flags;
> u16 ki_ioprio; /* See linux/ioprio.h */
> + u8 ki_write_stream;
> union {
> /*
> * Only used for async buffered reads, where it denotes the
> --
> 2.43.5
>