From 6bf8d16009cff0a5e945bb9055f1297ebfff7e85 Mon Sep 17 00:00:00 2001
From: Allan Jude <allanjude@FreeBSD.org>
Date: Sat, 30 Jul 2016 17:45:56 +0000
Subject: [PATCH] bcache should support reads shorter than sector size

dosfs (fat file systems) can perform reads of partial sectors
bcache should support such reads.

Submitted by:	Toomas Soome <tsoome@me.com>
Reviewed by:	cem
Differential Revision:	https://reviews.freebsd.org/D6475
---
 sys/boot/common/bcache.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/sys/boot/common/bcache.c b/sys/boot/common/bcache.c
index 4bb9082bea2..c935c90f938 100644
--- a/sys/boot/common/bcache.c
+++ b/sys/boot/common/bcache.c
@@ -303,7 +303,9 @@ read_strategy(void *devdata, int rw, daddr_t blk, size_t offset,
 	    break;
     }
 
-    size = i * bcache_blksize;
+    if (size > i * bcache_blksize)
+	size = i * bcache_blksize;
+
     if (size != 0) {
 	bcopy(bc->bcache_data + (bcache_blksize * BHASH(bc, blk)) + offset,
 	    buf, size);