--- imap-2001a/src/osdep/unix/os_lnx.h.flock	2002-10-17 13:59:58 +0400
+++ imap-2001a/src/osdep/unix/os_lnx.h	2002-10-17 13:59:58 +0400
@@ -47,3 +47,4 @@
 
 #define utime portable_utime
 int portable_utime (char *file,time_t timep[2]);
+#include "flocksim.h"
--- imap-2001a/src/osdep/unix/nfstold.c.flock	2001-04-11 01:20:31 +0400
+++ imap-2001a/src/osdep/unix/nfstold.c	2002-10-17 13:59:58 +0400
@@ -18,6 +18,10 @@
  * CPYRIGHT, included with this Distribution.
  */
 
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <ustat.h>
+
 /* Test for NFS
  * Accepts: file descriptor
  * Returns: T if NFS file, NIL otherwise
--- imap-2001a/src/osdep/unix/os_lnx.c.flock	2002-10-17 13:59:58 +0400
+++ imap-2001a/src/osdep/unix/os_lnx.c	2002-10-17 13:59:58 +0400
@@ -41,5 +41,7 @@
 #define fork vfork
 #include "tcp_unix.c"
 #include "gr_waitp.c"
+#include <string.h>
+#include "flocksim.c"
 #include "tz_sv4.c"
 #include "utime.c"
--- imap-2001a/src/osdep/unix/flocksim.c.flock	2001-11-06 19:49:29 +0300
+++ imap-2001a/src/osdep/unix/flocksim.c	2002-10-17 14:23:23 +0400
@@ -20,7 +20,7 @@
  
 #undef flock			/* name is used as a struct for fcntl */
 #undef fork			/* make damn sure that we don't use vfork!! */
-#include "nfstest.c"		/* get NFS tester */
+/* Do not care about NFS: treat it just as any other FS */
 
 #ifndef NSIG			/* don't know if this can happen */
 #define NSIG 32			/* a common maximum */
@@ -55,36 +55,56 @@
     return -1;
   }
 
-  /*  Make fcntl() locking of NFS files be a no-op the way it is with flock()
-   * on BSD.  This is because the rpc.statd/rpc.lockd daemons don't work very
+  /*  DO NOT make fcntl() locking of NFS files be a no-op the way it is with flock()
+   * on BSD.  We do not care if the rpc.statd/rpc.lockd daemons don't work very
    * well and cause cluster-wide hangs if you exercise them at all.  The
-   * result of this is that you lose the ability to detect shared mail_open()
-   * on NFS-mounted files.  If you are wise, you'll use IMAP instead of NFS
+   * result of this would be that you lose the ability to detect shared mail_open()
+   * on NFS-mounted files and on some other innocent files (e.g on reiserfs).
+   * If you are wise, you'll use IMAP instead of NFS
    * for mail files.
    *
+   * I suggest you to check this yourself if it applies to you:
    *  Sun alleges that it doesn't matter, because they say they have fixed all
    * the rpc.statd/rpc.lockd bugs.  This is absolutely not true; huge amounts
    * of user and support time have been wasted in cluster-wide hangs.
    */
-  if (test_nfs (fd) || mail_parameters (NIL,GET_DISABLEFCNTLLOCK,NIL))
+  if (mail_parameters (NIL,GET_DISABLEFCNTLLOCK,NIL)) {
+    /* give user a warning: it is not good in any case to have no locks */
+    sprintf (tmp,"Mailbox vulnerable - you disabled fcntl(2)-locking");                                                                                                           
+    MM_LOG (tmp,WARN);                                                                                                                                                         
     return 0;			/* fcntl() locking disabled, return success */
+  }
 				/* do the lock */
-  while (fcntl (fd,(op & LOCK_NB) ? F_SETLK : F_SETLKW,&fl))
-    if (errno != EINTR) {
-      /* Can't use switch here because these error codes may resolve to the
-       * same value on some systems.
-       */
-      if ((errno != EWOULDBLOCK) && (errno != EAGAIN) && (errno != EACCES)) {
-	sprintf (tmp,"Unexpected file locking failure: %s",strerror (errno));
-				/* give the user a warning of what happened */
+  while (fcntl (fd,(op & LOCK_NB) ? F_SETLK : F_SETLKW,&fl)) {
+    /* Can't use switch here because some error codes may resolve to the
+     * same value on some systems.
+     */
+    if   (errno == EINTR)        /* interrupt */
+      continue;
+    if ( (errno == ENOLCK)       /* lock table is full */
+	 || (errno == EDEADLK) ) /* system thinks it would cause a deadlock */
+      {
+	sprintf (tmp,"File locking failure: %s",strerror (errno));
+	/* give the user a warning of what happened */
 	MM_NOTIFY (NIL,tmp,WARN);
 	if (!logged++) syslog (LOG_ERR,"%s",tmp);
-	if (op & LOCK_NB) return -1;
-	sleep (5);		/* slow things down for loops */
+	if (op & LOCK_NB) return -1;/* return failure if non-blocking lock */
+	sleep (5);			/* slow down in case it loops */
+	continue;
       }
-				/* return failure for non-blocking lock */
-      else if (op & LOCK_NB) return -1;
-    }
+    if ( (errno == EACCES)		/* lock held by another process? */
+	 || (errno == EWOULDBLOCK)	/* file is locked */
+	  || (errno == EAGAIN) )
+      {
+	if (op & LOCK_NB) return -1;/* return failure if non-blocking lock */
+	continue;
+      }
+    /* case EBADF:			not valid open file descriptor */
+    /* case EINVAL:			invalid operator */
+    /* other error code? */
+    sprintf (tmp,"Unexpected file locking failure: %s",strerror (errno));
+    fatal (tmp);
+  }
   return 0;			/* success */
 }
 
--- imap-2001a/src/osdep/unix/nfstnew.c.flock	2001-04-13 00:37:59 +0400
+++ imap-2001a/src/osdep/unix/nfstnew.c	2002-10-17 13:59:58 +0400
@@ -19,6 +19,8 @@
  */
 
 #include <sys/statvfs.h>
+#include <sys/types.h>
+#include <ustat.h>
 
 /* Test for NFS
  * Accepts: file descriptor