Btrfs: do not mount when we have a sectorsize unequal to PAGE_SIZE

Our code is not ready to cope with a sectorsize that's not equal to PAGE_SIZE.
It will lead to hanging-on while writing something.

Signed-off-by: Liu Bo <liubo2009@cn.fujitsu.com>
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 20196f4..b9866f2 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -2254,9 +2254,9 @@
 		goto fail_sb_buffer;
 	}
 
-	if (sectorsize < PAGE_SIZE) {
-		printk(KERN_WARNING "btrfs: Incompatible sector size "
-		       "found on %s\n", sb->s_id);
+	if (sectorsize != PAGE_SIZE) {
+		printk(KERN_WARNING "btrfs: Incompatible sector size(%lu) "
+		       "found on %s\n", (unsigned long)sectorsize, sb->s_id);
 		goto fail_sb_buffer;
 	}