fix buf where concurrent fs syscalls race on log entries

3d2dedd4 · Cody Cutler · 41f16c21 · 3d2dedd4
--- 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);
 }