Re: [PATCHv11 00/10] block write streams with nvme fdp

[Keith Busch <kbusch@kernel.org>]

On Thu, Dec 05, 2024 at 05:52:58PM -0800, Keith Busch wrote:
> Changes from v10:
> 
>  Merged up to block for-6.14/io_uring, which required some
>  new attribute handling.
> 
>  Not mixing write hints usage with write streams. This effectively
>  abandons any attempts to use the existing fcntl API for use with
>  filesystems in this series.
> 
>  Exporting the stream's reclaim unit nominal size.
> 
> Christoph Hellwig (5):
>   fs: add a write stream field to the kiocb
>   block: add a bi_write_stream field
>   block: introduce a write_stream_granularity queue limit
>   block: expose write streams for block device nodes
>   nvme: add a nvme_get_log_lsi helper
> 
> Keith Busch (5):
>   io_uring: protection information enhancements
>   io_uring: add write stream attribute
>   block: introduce max_write_streams queue limit
>   nvme: register fdp queue limits
>   nvme: use fdp streams if write stream is provided

I fucked up the format-patch command by ommitting a single patch. The
following should have been "PATCH 1/11", but I don't want to resend for
just this:

commit 9e40f4a4da6d0cef871d1c5daf55cc0497fd9c39
Author: Keith Busch <kbusch@kernel.org>
Date:   Tue Nov 19 13:16:15 2024 +0100

    fs: add write stream information to statx
    
    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: renamed hints to streams, add granularity]
    Signed-off-by: Christoph Hellwig <hch@lst.de>

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 */
 };
 
@@ -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 */