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

Keith Busch
2024-12-06T22:24:17Z

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 */
};

@@ -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