From 833216fef8b946895956737d205bcad7031bf06f Mon Sep 17 00:00:00 2001
From: Russ Cox <rsc@swtch.com>
Date: Sat, 19 Apr 2014 13:44:06 -0400
Subject: acme: add comment for aligned writes

TBR=r
https://codereview.appspot.com/89510044
---
 src/cmd/acme/exec.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/src/cmd/acme/exec.c b/src/cmd/acme/exec.c
index 0ef66847..6f8bf3f6 100644
--- a/src/cmd/acme/exec.c
+++ b/src/cmd/acme/exec.c
@@ -662,6 +662,11 @@ putfile(File *f, int q0, int q1, Rune *namer, int nname)
 		warning(nil, "can't create file %s: %r\n", name);
 		goto Rescue1;
 	}
+	// Use bio in order to force the writes to be large and
+	// block-aligned (bio's default is 8K). This is not strictly
+	// necessary; it works around some buggy underlying
+	// file systems that mishandle unaligned writes.
+	// https://codereview.appspot.com/89550043/
 	b = emalloc(sizeof *b);
 	Binit(b, fd, OWRITE);
 	r = fbufalloc();
-- 
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