Unverified Commit cf40ebb2 authored by Christian Brauner's avatar Christian Brauner
Browse files

Merge patch series "add STATX_DIO_READ_ALIGN v3" 

Christoph Hellwig <hch@lst.de> says:

File systems that write out of place usually require different alignment
for direct I/O writes than what they can do for reads.  This series tries
to address this by adding yet another statx field.

* patches from https://lore.kernel.org/r/20250109083109.1441561-1-hch@lst.de:
  xfs: report larger dio alignment for COW inodes
  xfs: report the correct read/write dio alignment for reflinked inodes
  xfs: cleanup xfs_vn_getattr
  fs: add STATX_DIO_READ_ALIGN
  fs: reformat the statx definition

Link: https://lore.kernel.org/r/20250109083109.1441561-1-hch@lst.de


Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
parents 40384c84 468210ec

fs/stat.c

+1 −0
Original line number Diff line number Diff line
@@ -725,6 +725,7 @@ cp_statx(const struct kstat *stat, struct statx __user *buffer) 
	tmp.stx_mnt_id = stat->mnt_id;

	tmp.stx_dio_mem_align = stat->dio_mem_align;

	tmp.stx_dio_offset_align = stat->dio_offset_align;

	tmp.stx_dio_read_offset_align = stat->dio_read_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;

fs/xfs/xfs_ioctl.c

+10 −1
Original line number Diff line number Diff line
@@ -1204,7 +1204,16 @@ xfs_file_ioctl( 
		struct xfs_buftarg	*target = xfs_inode_buftarg(ip);

		struct dioattr		da;



		da.d_mem =  da.d_miniosz = target->bt_logical_sectorsize;

		da.d_mem = target->bt_logical_sectorsize;



		/*

		 * See xfs_report_dioalign() for an explanation about why this

		 * reports a value larger than the sector size for COW inodes.

		 */

		if (xfs_is_cow_inode(ip))

			da.d_miniosz = xfs_inode_alloc_unitsize(ip);

		else

			da.d_miniosz = target->bt_logical_sectorsize;

		da.d_maxiosz = INT_MAX & ~(da.d_miniosz - 1);



		if (copy_to_user(arg, &da, sizeof(da)))

fs/xfs/xfs_iops.c

+38 −24
Original line number Diff line number Diff line
@@ -573,17 +573,43 @@ xfs_stat_blksize( 
}



static void

xfs_get_atomic_write_attr(

xfs_report_dioalign(

	struct xfs_inode	*ip,

	unsigned int		*unit_min,

	unsigned int		*unit_max)

	struct kstat		*stat)

{

	if (!xfs_inode_can_atomicwrite(ip)) {

		*unit_min = *unit_max = 0;

		return;

	struct xfs_buftarg	*target = xfs_inode_buftarg(ip);

	struct block_device	*bdev = target->bt_bdev;



	stat->result_mask |= STATX_DIOALIGN | STATX_DIO_READ_ALIGN;

	stat->dio_mem_align = bdev_dma_alignment(bdev) + 1;



	/*

	 * For COW inodes, we can only perform out of place writes of entire

	 * allocation units (blocks or RT extents).

	 * For writes smaller than the allocation unit, we must fall back to

	 * buffered I/O to perform read-modify-write cycles.  At best this is

	 * highly inefficient; at worst it leads to page cache invalidation

	 * races.  Tell applications to avoid this by reporting the larger write

	 * alignment in dio_offset_align, and the smaller read alignment in

	 * dio_read_offset_align.

	 */

	stat->dio_read_offset_align = bdev_logical_block_size(bdev);

	if (xfs_is_cow_inode(ip))

		stat->dio_offset_align = xfs_inode_alloc_unitsize(ip);

	else

		stat->dio_offset_align = stat->dio_read_offset_align;

}



	*unit_min = *unit_max = ip->i_mount->m_sb.sb_blocksize;

static void

xfs_report_atomic_write(

	struct xfs_inode	*ip,

	struct kstat		*stat)

{

	unsigned int		unit_min = 0, unit_max = 0;



	if (xfs_inode_can_atomicwrite(ip))

		unit_min = unit_max = ip->i_mount->m_sb.sb_blocksize;

	generic_fill_statx_atomic_writes(stat, unit_min, unit_max);

}



STATIC int
@@ -647,22 +673,10 @@ xfs_vn_getattr( 
		stat->rdev = inode->i_rdev;

		break;

	case S_IFREG:

		if (request_mask & STATX_DIOALIGN) {

			struct xfs_buftarg	*target = xfs_inode_buftarg(ip);

			struct block_device	*bdev = target->bt_bdev;



			stat->result_mask |= STATX_DIOALIGN;

			stat->dio_mem_align = bdev_dma_alignment(bdev) + 1;

			stat->dio_offset_align = bdev_logical_block_size(bdev);

		}

		if (request_mask & STATX_WRITE_ATOMIC) {

			unsigned int	unit_min, unit_max;



			xfs_get_atomic_write_attr(ip, &unit_min,

					&unit_max);

			generic_fill_statx_atomic_writes(stat,

					unit_min, unit_max);

		}

		if (request_mask & (STATX_DIOALIGN | STATX_DIO_READ_ALIGN))

			xfs_report_dioalign(ip, stat);

		if (request_mask & STATX_WRITE_ATOMIC)

			xfs_report_atomic_write(ip, stat);

		fallthrough;

	default:

		stat->blksize = xfs_stat_blksize(ip);

include/linux/stat.h

+1 −0
Original line number Diff line number Diff line
@@ -52,6 +52,7 @@ struct kstat { 
	u64		mnt_id;

	u32		dio_mem_align;

	u32		dio_offset_align;

	u32		dio_read_offset_align;

	u64		change_cookie;

	u64		subvol;

	u32		atomic_write_unit_min;

include/uapi/linux/stat.h

+75 −24
Original line number Diff line number Diff line
@@ -98,43 +98,93 @@ struct statx_timestamp { 
 */

struct statx {

	/* 0x00 */

	__u32	stx_mask;	/* What results were written [uncond] */

	__u32	stx_blksize;	/* Preferred general I/O size [uncond] */

	__u64	stx_attributes;	/* Flags conveying information about the file [uncond] */

	/* What results were written [uncond] */

	__u32	stx_mask;



	/* Preferred general I/O size [uncond] */

	__u32	stx_blksize;



	/* Flags conveying information about the file [uncond] */

	__u64	stx_attributes;



	/* 0x10 */

	__u32	stx_nlink;	/* Number of hard links */

	__u32	stx_uid;	/* User ID of owner */

	__u32	stx_gid;	/* Group ID of owner */

	__u16	stx_mode;	/* File mode */

	/* Number of hard links */

	__u32	stx_nlink;



	/* User ID of owner */

	__u32	stx_uid;



	/* Group ID of owner */

	__u32	stx_gid;



	/* File mode */

	__u16	stx_mode;

	__u16	__spare0[1];



	/* 0x20 */

	__u64	stx_ino;	/* Inode number */

	__u64	stx_size;	/* File size */

	__u64	stx_blocks;	/* Number of 512-byte blocks allocated */

	__u64	stx_attributes_mask; /* Mask to show what's supported in stx_attributes */

	/* Inode number */

	__u64	stx_ino;



	/* File size */

	__u64	stx_size;



	/* Number of 512-byte blocks allocated */

	__u64	stx_blocks;



	/* Mask to show what's supported in stx_attributes */

	__u64	stx_attributes_mask;



	/* 0x40 */

	struct statx_timestamp	stx_atime;	/* Last access time */

	struct statx_timestamp	stx_btime;	/* File creation time */

	struct statx_timestamp	stx_ctime;	/* Last attribute change time */

	struct statx_timestamp	stx_mtime;	/* Last data modification time */

	/* Last access time */

	struct statx_timestamp	stx_atime;



	/* File creation time */

	struct statx_timestamp	stx_btime;



	/* Last attribute change time */

	struct statx_timestamp	stx_ctime;



	/* Last data modification time */

	struct statx_timestamp	stx_mtime;



	/* 0x80 */

	__u32	stx_rdev_major;	/* Device ID of special file [if bdev/cdev] */

	/* Device ID of special file [if bdev/cdev] */

	__u32	stx_rdev_major;

	__u32	stx_rdev_minor;

	__u32	stx_dev_major;	/* ID of device containing file [uncond] */



	/* ID of device containing file [uncond] */

	__u32	stx_dev_major;

	__u32	stx_dev_minor;



	/* 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 */



	/* Memory buffer alignment for direct I/O */

	__u32	stx_dio_mem_align;



	/* File offset alignment for direct I/O */

	__u32	stx_dio_offset_align;



	/* 0xa0 */

	__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 */

	/* Subvolume identifier */

	__u64	stx_subvol;



	/* Min atomic write unit in bytes */

	__u32	stx_atomic_write_unit_min;



	/* Max atomic write unit in bytes */

	__u32	stx_atomic_write_unit_max;



	/* 0xb0 */

	__u32   stx_atomic_write_segments_max;	/* Max atomic write segment count */

	__u32   __spare1[1];

	/* Max atomic write segment count */

	__u32   stx_atomic_write_segments_max;



	/* File offset alignment for direct I/O reads */

	__u32	stx_dio_read_offset_align;



	/* 0xb8 */

	__u64	__spare3[9];	/* Spare space for future expansion */



	/* 0x100 */

};
@@ -164,6 +214,7 @@ 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_DIO_READ_ALIGN	0x00020000U	/* Want/got dio read alignment info */



#define STATX__RESERVED		0x80000000U	/* Reserved for future struct statx expansion */