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From: John Garry <[email protected]>
To: [email protected], [email protected], [email protected], [email protected],
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Cc: [email protected], [email protected],
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	[email protected], [email protected],
	[email protected], [email protected],
	Prasad Singamsetty <[email protected]>,
	John Garry <[email protected]>
Subject: [Patch v9 04/10] fs: Add initial atomic write support info to statx
Date: Thu, 20 Jun 2024 12:53:53 +0000	[thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>

From: Prasad Singamsetty <[email protected]>

Extend statx system call to return additional info for atomic write support
support for a file.

Helper function generic_fill_statx_atomic_writes() can be used by FSes to
fill in the relevant statx fields. For now atomic_write_segments_max will
always be 1, otherwise some rules would need to be imposed on iovec length
and alignment, which we don't want now.

Signed-off-by: Prasad Singamsetty <[email protected]>
jpg: relocate bdev support to another patch
Reviewed-by: "Darrick J. Wong" <[email protected]>
Reviewed-by: Martin K. Petersen <[email protected]>
Signed-off-by: John Garry <[email protected]>
---
 fs/stat.c                 | 34 ++++++++++++++++++++++++++++++++++
 include/linux/fs.h        |  3 +++
 include/linux/stat.h      |  3 +++
 include/uapi/linux/stat.h | 12 ++++++++++--
 4 files changed, 50 insertions(+), 2 deletions(-)

diff --git a/fs/stat.c b/fs/stat.c
index 70bd3e888cfa..72d0e6357b91 100644
--- a/fs/stat.c
+++ b/fs/stat.c
@@ -89,6 +89,37 @@ void generic_fill_statx_attr(struct inode *inode, struct kstat *stat)
 }
 EXPORT_SYMBOL(generic_fill_statx_attr);
 
+/**
+ * generic_fill_statx_atomic_writes - Fill in atomic writes statx attributes
+ * @stat:	Where to fill in the attribute flags
+ * @unit_min:	Minimum supported atomic write length in bytes
+ * @unit_max:	Maximum supported atomic write length in bytes
+ *
+ * Fill in the STATX{_ATTR}_WRITE_ATOMIC flags in the kstat structure from
+ * atomic write unit_min and unit_max values.
+ */
+void generic_fill_statx_atomic_writes(struct kstat *stat,
+				      unsigned int unit_min,
+				      unsigned int unit_max)
+{
+	/* Confirm that the request type is known */
+	stat->result_mask |= STATX_WRITE_ATOMIC;
+
+	/* Confirm that the file attribute type is known */
+	stat->attributes_mask |= STATX_ATTR_WRITE_ATOMIC;
+
+	if (unit_min) {
+		stat->atomic_write_unit_min = unit_min;
+		stat->atomic_write_unit_max = unit_max;
+		/* Initially only allow 1x segment */
+		stat->atomic_write_segments_max = 1;
+
+		/* Confirm atomic writes are actually supported */
+		stat->attributes |= STATX_ATTR_WRITE_ATOMIC;
+	}
+}
+EXPORT_SYMBOL_GPL(generic_fill_statx_atomic_writes);
+
 /**
  * vfs_getattr_nosec - getattr without security checks
  * @path: file to get attributes from
@@ -659,6 +690,9 @@ cp_statx(const struct kstat *stat, struct statx __user *buffer)
 	tmp.stx_dio_mem_align = stat->dio_mem_align;
 	tmp.stx_dio_offset_align = stat->dio_offset_align;
 	tmp.stx_subvol = stat->subvol;
+	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;
 
 	return copy_to_user(buffer, &tmp, sizeof(tmp)) ? -EFAULT : 0;
 }
diff --git a/include/linux/fs.h b/include/linux/fs.h
index e049414bef7d..db26b4a70c62 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -3235,6 +3235,9 @@ extern const struct inode_operations page_symlink_inode_operations;
 extern void kfree_link(void *);
 void generic_fillattr(struct mnt_idmap *, u32, struct inode *, struct kstat *);
 void generic_fill_statx_attr(struct inode *inode, struct kstat *stat);
+void generic_fill_statx_atomic_writes(struct kstat *stat,
+				      unsigned int unit_min,
+				      unsigned int unit_max);
 extern int vfs_getattr_nosec(const struct path *, struct kstat *, u32, unsigned int);
 extern int vfs_getattr(const struct path *, struct kstat *, u32, unsigned int);
 void __inode_add_bytes(struct inode *inode, loff_t bytes);
diff --git a/include/linux/stat.h b/include/linux/stat.h
index bf92441dbad2..3d900c86981c 100644
--- a/include/linux/stat.h
+++ b/include/linux/stat.h
@@ -54,6 +54,9 @@ struct kstat {
 	u32		dio_offset_align;
 	u64		change_cookie;
 	u64		subvol;
+	u32		atomic_write_unit_min;
+	u32		atomic_write_unit_max;
+	u32		atomic_write_segments_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 67626d535316..887a25286441 100644
--- a/include/uapi/linux/stat.h
+++ b/include/uapi/linux/stat.h
@@ -126,9 +126,15 @@ struct statx {
 	__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 */
-	__u64	stx_subvol;	/* Subvolume identifier */
 	/* 0xa0 */
-	__u64	__spare3[11];	/* Spare space for future expansion */
+	__u64	stx_subvol;	/* Subvolume identifier */
+	__u32	stx_atomic_write_unit_min;	/* Min atomic write unit in bytes */
+	__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];
+	/* 0xb8 */
+	__u64	__spare3[9];	/* Spare space for future expansion */
 	/* 0x100 */
 };
 
@@ -157,6 +163,7 @@ struct statx {
 #define STATX_DIOALIGN		0x00002000U	/* Want/got direct I/O alignment info */
 #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__RESERVED		0x80000000U	/* Reserved for future struct statx expansion */
 
@@ -192,6 +199,7 @@ struct statx {
 #define STATX_ATTR_MOUNT_ROOT		0x00002000 /* Root of a mount */
 #define STATX_ATTR_VERITY		0x00100000 /* [I] Verity protected file */
 #define STATX_ATTR_DAX			0x00200000 /* File is currently in DAX state */
+#define STATX_ATTR_WRITE_ATOMIC		0x00400000 /* File supports atomic write operations */
 
 
 #endif /* _UAPI_LINUX_STAT_H */
-- 
2.31.1


  parent reply	other threads:[~2024-06-20 12:55 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-06-20 12:53 [Patch v9 00/10] block atomic writes John Garry
2024-06-20 12:53 ` [Patch v9 01/10] block: Pass blk_queue_get_max_sectors() a request pointer John Garry
2024-06-20 14:12   ` Hannes Reinecke
2024-06-20 12:53 ` [Patch v9 02/10] block: Generalize chunk_sectors support as boundary support John Garry
2024-06-20 14:14   ` Hannes Reinecke
2024-06-20 12:53 ` [Patch v9 03/10] fs: Initial atomic write support John Garry
2024-06-21  5:56   ` Hannes Reinecke
2024-06-20 12:53 ` John Garry [this message]
2024-06-21  5:57   ` [Patch v9 04/10] fs: Add initial atomic write support info to statx Hannes Reinecke
2024-06-20 12:53 ` [Patch v9 05/10] block: Add core atomic write support John Garry
2024-06-20 19:34   ` Keith Busch
2024-06-21  6:09   ` Hannes Reinecke
2024-06-21  7:41     ` John Garry
2024-06-20 12:53 ` [Patch v9 06/10] block: Add atomic write support for statx John Garry
2024-06-20 19:46   ` Keith Busch
2024-06-21  6:10   ` Hannes Reinecke
2024-06-20 12:53 ` [Patch v9 07/10] block: Add fops atomic write support John Garry
2024-06-20 19:46   ` Keith Busch
2024-06-21  6:13   ` Hannes Reinecke
2024-06-21 12:02     ` John Garry
2024-06-21 21:23       ` Darrick J. Wong
2024-06-21  9:41   ` Kanchan Joshi
2024-06-20 12:53 ` [Patch v9 08/10] scsi: sd: Atomic " John Garry
2024-06-21  6:15   ` Hannes Reinecke
2024-06-20 12:53 ` [Patch v9 09/10] scsi: scsi_debug: " John Garry
2024-06-21  6:15   ` Hannes Reinecke
2024-06-20 12:53 ` [Patch v9 10/10] nvme: " John Garry
2024-06-20 20:36   ` Keith Busch
2024-06-21  6:17   ` Hannes Reinecke
2024-06-21  9:40   ` Kanchan Joshi
2024-06-20 21:23 ` [Patch v9 00/10] block atomic writes Jens Axboe
2024-06-21  7:59   ` John Garry
2024-06-21 14:28     ` Jens Axboe
2024-06-21 14:41       ` John Garry

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