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[v5,8/8] xfs: support STATX_DIOALIGN

Message ID 20220827065851.135710-9-ebiggers@kernel.org
State Not Applicable
Headers show
Series make statx() return DIO alignment information | expand

Commit Message

Eric Biggers Aug. 27, 2022, 6:58 a.m. UTC 
From: Eric Biggers <ebiggers@google.com>

Add support for STATX_DIOALIGN to xfs, so that direct I/O alignment
restrictions are exposed to userspace in a generic way.

Signed-off-by: Eric Biggers <ebiggers@google.com>
---
 fs/xfs/xfs_iops.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

Comments

Darrick J. Wong Aug. 27, 2022, 3:34 p.m. UTC | #1 
On Fri, Aug 26, 2022 at 11:58:51PM -0700, Eric Biggers wrote:
> From: Eric Biggers <ebiggers@google.com>
> 
> Add support for STATX_DIOALIGN to xfs, so that direct I/O alignment
> restrictions are exposed to userspace in a generic way.
> 
> Signed-off-by: Eric Biggers <ebiggers@google.com>

Looks good to me; I particularly like the adjustment to report the
device's DMA alignment.  Someone should probably fix DIONINFO, or
perhaps turn it into a getattr wrapper and hoist it?  IMHO none of those
suggestions are necessary to land this patch, though.

Reviewed-by: Darrick J. Wong <djwong@kernel.org>

--D

> ---
>  fs/xfs/xfs_iops.c | 10 ++++++++++
>  1 file changed, 10 insertions(+)
> 
> diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c
> index 45518b8c613c9a..f51c60d7e2054a 100644
> --- a/fs/xfs/xfs_iops.c
> +++ b/fs/xfs/xfs_iops.c
> @@ -604,6 +604,16 @@ xfs_vn_getattr(
>  		stat->blksize = BLKDEV_IOSIZE;
>  		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);
> +		}
> +		fallthrough;
>  	default:
>  		stat->blksize = xfs_stat_blksize(ip);
>  		stat->rdev = 0;
> -- 
> 2.37.2
>
Christoph Hellwig Sept. 6, 2022, 8:11 a.m. UTC | #2 
Looks good:

Reviewed-by: Christoph Hellwig <hch@lst.de>
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Patch

diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c
index 45518b8c613c9a..f51c60d7e2054a 100644
--- a/fs/xfs/xfs_iops.c
+++ b/fs/xfs/xfs_iops.c
@@ -604,6 +604,16 @@  xfs_vn_getattr(
 		stat->blksize = BLKDEV_IOSIZE;
 		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);
+		}
+		fallthrough;
 	default:
 		stat->blksize = xfs_stat_blksize(ip);
 		stat->rdev = 0;