diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index d535ed39c391..03771f09a9a2 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -7578,8 +7578,12 @@ static int btrfs_dio_iomap_begin(struct inode *inode, loff_t start,
 	const u64 data_alloc_len = length;
 	bool unlock_extents = false;
 
+	/*
+	 * Cap the size of reads to that usually seen in buffered I/O as we need
+	 * to allocate a contiguous array for the checksums.
+	 */
 	if (!write)
-		len = min_t(u64, len, fs_info->sectorsize);
+		len = min_t(u64, len, fs_info->sectorsize * BTRFS_MAX_BIO_SECTORS);
 
 	lockstart = start;
 	lockend = start + len - 1;
diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index b61508723d5d..9537d82bb7a2 100644
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -354,6 +354,13 @@ struct btrfs_fs_devices {
 				- 2 * sizeof(struct btrfs_chunk))	\
 				/ sizeof(struct btrfs_stripe) + 1)
 
+/*
+ * Maximum number of sectors for a single bio to limit the size of the
+ * checksum array.  This matches the number of bio_vecs per bio and thus the
+ * I/O size for buffered I/O.
+ */
+#define BTRFS_MAX_BIO_SECTORS				(256)
+
 /*
  * Additional info to pass along bio.
  *