--- libeio/eio.c	2008/09/30 13:17:32	1.24
+++ libeio/eio.c	2009/06/03 12:24:49	1.30
@@ -38,6 +38,10 @@
  */
 
 #include "eio.h"
+
+#ifdef EIO_STACKSIZE
+# define XTHREAD_STACKSIZE EIO_STACKSIZE
+#endif
 #include "xthread.h"
 
 #include <errno.h>
@@ -606,12 +610,12 @@
 {
   while (grp->size < grp->int2 && !EIO_CANCELLED (grp))
     {
-      int old_len = grp->size;
+      grp->flags &= ~EIO_FLAG_GROUPADD;
 
       EIO_FEED (grp);
 
       /* stop if no progress has been made */
-      if (old_len == grp->size)
+      if (!(grp->flags & EIO_FLAG_GROUPADD))
         {
           grp->feed = 0;
           break;
@@ -738,6 +742,8 @@
 /* work around various missing functions */
 
 #if !HAVE_PREADWRITE
+# undef pread
+# undef pwrite
 # define pread  eio__pread
 # define pwrite eio__pwrite
 
@@ -767,7 +773,7 @@
   ooffset = lseek (fd, 0, SEEK_CUR);
   lseek (fd, offset, SEEK_SET);
   res = write (fd, buf, count);
-  lseek (fd, offset, SEEK_SET);
+  lseek (fd, ooffset, SEEK_SET);
   X_UNLOCK (preadwritelock);
 
   return res;
@@ -776,6 +782,8 @@
 
 #ifndef HAVE_FUTIMES
 
+# undef utimes
+# undef futimes
 # define utimes(path,times)  eio__utimes  (path, times)
 # define futimes(fd,times)   eio__futimes (fd, times)
 
@@ -804,10 +812,40 @@
 #endif
 
 #if !HAVE_FDATASYNC
-# define fdatasync fsync
+# undef fdatasync
+# define fdatasync(fd) fsync (fd)
+#endif
+
+/* sync_file_range always needs emulation */
+int
+eio__sync_file_range (int fd, off_t offset, size_t nbytes, unsigned int flags)
+{
+#if HAVE_SYNC_FILE_RANGE
+  int res;
+
+  if (EIO_SYNC_FILE_RANGE_WAIT_BEFORE   != SYNC_FILE_RANGE_WAIT_BEFORE
+      || EIO_SYNC_FILE_RANGE_WRITE      != SYNC_FILE_RANGE_WRITE
+      || EIO_SYNC_FILE_RANGE_WAIT_AFTER != SYNC_FILE_RANGE_WAIT_AFTER)
+    {
+      flags = 0
+         | (flags & EIO_SYNC_FILE_RANGE_WAIT_BEFORE ? SYNC_FILE_RANGE_WAIT_BEFORE : 0)
+         | (flags & EIO_SYNC_FILE_RANGE_WRITE       ? SYNC_FILE_RANGE_WRITE       : 0)
+         | (flags & EIO_SYNC_FILE_RANGE_WAIT_AFTER  ? SYNC_FILE_RANGE_WAIT_AFTER  : 0);
+    }
+
+  res = sync_file_range (fd, offset, nbytes, flags);
+
+  if (!res || errno != ENOSYS)
+    return res;
 #endif
 
+  /* even though we could play tricks with the flags, it's better to always
+   * call fdatasync, as thta matches the expectation of it's users best */
+  return fdatasync (fd);
+}
+
 #if !HAVE_READAHEAD
+# undef readahead
 # define readahead(fd,offset,count) eio__readahead (fd, offset, count, self)
 
 static ssize_t
@@ -983,7 +1021,8 @@
 }
 
 #if !(_POSIX_MAPPED_FILES && _POSIX_SYNCHRONIZED_IO)
-# define msync(a,b,c) ENOSYS
+# undef msync
+# define msync(a,b,c) ((errno = ENOSYS), -1)
 #endif
 
 int
@@ -1187,6 +1226,7 @@
       case EIO_FDATASYNC: req->result = fdatasync (req->int1); break;
       case EIO_MSYNC:     req->result = msync (req->ptr2, req->size, req->int1); break;
       case EIO_MTOUCH:    req->result = eio__mtouch (req->ptr2, req->size, req->int1); break;
+      case EIO_SYNC_FILE_RANGE: req->result = eio__sync_file_range (req->int1, req->offs, req->size, req->int2); break;
 
       case EIO_READDIR:   eio__scandir (req, self); break;
 
@@ -1228,6 +1268,7 @@
                         ? futimes (req->int1, times)
                         : utimes  (req->ptr1, times);
         }
+        break;
 
       case EIO_GROUP:
         abort (); /* handled in eio_request */
@@ -1280,6 +1321,11 @@
   REQ (EIO_MTOUCH); req->ptr2 = addr; req->size = length; req->int1 = flags; SEND;
 }
 
+eio_req *eio_sync_file_range (int fd, off_t offset, size_t nbytes, unsigned int flags, int pri, eio_cb cb, void *data)
+{
+  REQ (EIO_SYNC_FILE_RANGE); req->int1 = fd; req->offs = offset; req->size = nbytes; req->int2 = flags; SEND;
+}
+
 eio_req *eio_fdatasync (int fd, int pri, eio_cb cb, void *data)
 {
   REQ (EIO_FDATASYNC); req->int1 = fd; SEND;
@@ -1482,6 +1528,8 @@
 {
   assert (("cannot add requests to IO::AIO::GRP after the group finished", grp->int1 != 2));
 
+  grp->flags |= EIO_FLAG_GROUPADD;
+
   ++grp->size;
   req->grp = grp;