From 3d2dedd42714fc4eb7844b17b62669e287f27583 Mon Sep 17 00:00:00 2001
From: Cody Cutler <ccutler@csail.mit.edu>
Date: Thu, 19 Feb 2015 11:51:47 -0500
Subject: [PATCH] fix buf where concurrent fs syscalls race on log entries

---
 log.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/log.c b/log.c
index b66074c..f519a8c 100644
--- a/log.c
+++ b/log.c
@@ -217,6 +217,7 @@ log_write(struct buf *b)
   if (log.outstanding < 1)
     panic("log_write outside of trans");
 
+  acquire(&log.lock);
   for (i = 0; i < log.lh.n; i++) {
     if (log.lh.sector[i] == b->sector)   // log absorbtion
       break;
@@ -225,5 +226,6 @@ log_write(struct buf *b)
   if (i == log.lh.n)
     log.lh.n++;
   b->flags |= B_DIRTY; // prevent eviction
+  release(&log.lock);
 }