[PATCH 13/21] xfs: require file system block size alignment when using data checksums

[Christoph Hellwig <hch@lst.de>]

The checksums cover a whole block, so we can't read or update parts of a
block.  Report the requirement and enforce it for direct I/O reads.
Direct I/O writes already require file system block size alignment when
using the zoned allocator, and buffered I/O never does sub-block I/O.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 fs/xfs/xfs_file.c  | 14 +++++++++++++-
 fs/xfs/xfs_ioend.c | 13 +++++++++++--
 fs/xfs/xfs_iops.c  | 10 +++++++++-
 3 files changed, 33 insertions(+), 4 deletions(-)

diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index 6f25879b6510..5b25f33527c0 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -29,6 +29,7 @@
 #include "xfs_zone_alloc.h"
 #include "xfs_error.h"
 #include "xfs_errortag.h"
+#include "xfs_rtcsum.h"
 
 #include <linux/dax.h>
 #include <linux/falloc.h>
@@ -270,9 +271,20 @@ xfs_file_dio_read(
 	if (ret)
 		return ret;
 	if (mapping_stable_writes(iocb->ki_filp->f_mapping)) {
+		unsigned int		dio_flags = 0;
+
+		/*
+		 * Each checksums covers a whole file system block, and thus
+		 * sub-fsblock reads are not supported for file systems using
+		 * data checksums.
+		 */
+		if (xfs_is_rtcsum_inode(ip))
+			dio_flags |= IOMAP_DIO_FSBLOCK_ALIGNED;
 		ret = iomap_dio_rw(iocb, to, &xfs_read_iomap_ops,
-				&xfs_dio_read_bounce_ops, 0, NULL, 0);
+				&xfs_dio_read_bounce_ops, dio_flags, NULL, 0);
 	} else {
+		ASSERT(!xfs_is_rtcsum_inode(ip));
+
 		ret = iomap_dio_read_simple(iocb, to, xfs_read_iomap_begin);
 		if (ret == -ENOTBLK)
 			ret = iomap_dio_rw(iocb, to, &xfs_read_iomap_ops, NULL,
diff --git a/fs/xfs/xfs_ioend.c b/fs/xfs/xfs_ioend.c
index f0e01ac34de8..54bd0995ac29 100644
--- a/fs/xfs/xfs_ioend.c
+++ b/fs/xfs/xfs_ioend.c
@@ -44,6 +44,15 @@ xfs_bounce_submit_ioend(
 	submit_bio(&ioend->io_bio);
 }
 
+static unsigned int
+xfs_read_bounce_minsize(
+	struct iomap_ioend	*ioend)
+{
+	if (xfs_is_rtcsum_inode(XFS_I(ioend->io_inode)))
+		return i_blocksize(ioend->io_inode);
+	return bdev_logical_block_size(ioend->io_bio.bi_bdev);
+}
+
 static void
 xfs_end_bio_bounced(
 	struct bio		*bio)
@@ -86,7 +95,7 @@ xfs_read_bounce_and_resubmit(
 		.bi_offset	= ioend->io_bvec_offset,
 	};
 	bio->bi_end_io = xfs_end_bio_bounced;
-	iomap_bounce_read(ioend, bdev_logical_block_size(bio->bi_bdev),
+	iomap_bounce_read(ioend, xfs_read_bounce_minsize(ioend),
 			xfs_bounce_submit_ioend);
 	memalloc_nofs_restore(nofs_flag);
 }
@@ -134,7 +143,7 @@ xfs_ioend_submit_read(
 	ioend = iomap_init_ioend(inode, bio, file_offset, ioend_flags);
 	if ((ioend_flags & IOMAP_IOEND_DIRECT) &&
 	    READ_ONCE(mp->m_read_bounce) == XFS_READ_BOUNCE_ALWAYS) {
-		iomap_bounce_read(ioend, bdev_logical_block_size(bio->bi_bdev),
+		iomap_bounce_read(ioend, xfs_read_bounce_minsize(ioend),
 				xfs_bounce_submit_ioend);
 		return;
 	}
diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c
index d1306e723899..a5f01e2e3a67 100644
--- a/fs/xfs/xfs_iops.c
+++ b/fs/xfs/xfs_iops.c
@@ -581,6 +581,15 @@ xfs_report_dioalign(
 	stat->result_mask |= STATX_DIOALIGN | STATX_DIO_READ_ALIGN;
 	stat->dio_mem_align = bdev_dma_alignment(bdev) + 1;
 
+	/*
+	 * Each checksums covers a whole file system block, and thus sub-fsblock
+	 * reads are not supported for file systems using data checksums.
+	 */
+	if (xfs_is_rtcsum_inode(ip))
+		stat->dio_read_offset_align = xfs_inode_alloc_unitsize(ip);
+	else
+		stat->dio_read_offset_align = bdev_logical_block_size(bdev);
+
 	/*
 	 * For COW inodes, we can only perform out of place writes of entire
 	 * allocation units (blocks or RT extents).
@@ -591,7 +600,6 @@ xfs_report_dioalign(
 	 * 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
-- 
2.53.0