upas/fs: remove imap lastread debounding

[plan9front.git] / sys / src / cmd / lock.c

diff --git a/sys/src/cmd/lock.c b/sys/src/cmd/lock.c
index 1b2197f0d336fe3824780ee6f1a8225555ee9325..27210259aa94ed1d2577a9a96a14b9fe00cc6ae6 100644 (file)
--- a/sys/src/cmd/lock.c
+++ b/sys/src/cmd/lock.c
@@ -41,24 +41,28 @@ waitfor(int pid)
 static int
 openlock(char *lock)
 {
-       int lckfd;
+       int lckfd, didwstat = 0;
        Dir *dir;
 
-       if (lockwait)
-               while ((lckfd = open(lock, ORDWR)) < 0)
-                       sleep(1000);
-       else
-               lckfd = open(lock, ORDWR);
+Reopen:
+       while ((lckfd = open(lock, ORDWR)) < 0 && lockwait)
+               sleep(1000);
        if (lckfd < 0)
                sysfatal("can't open %s read/write: %r", lock);
        dir = dirfstat(lckfd);
        if (dir == nil)
                sysfatal("can't fstat %s: %r", lock);
        if (!(dir->mode & DMEXCL)) {
+               if(didwstat++)
+                       sysfatal("exclusive bit does not stick for %s", lock);
                dir->mode |= DMEXCL;
                dir->qid.type |= QTEXCL;
                if (dirfwstat(lckfd, dir) < 0)
                        sysfatal("can't make %s exclusive access: %r", lock);
+               /* reopen for lock to be effective */
+               free(dir);
+               close(lckfd);
+               goto Reopen;
        }
        free(dir);
        return lckfd;