1 files changed, 111 insertions, 0 deletions
diff --git a/libdiskfs/readonly.c b/libdiskfs/readonly.c
new file mode 100644
index 00000000..02f583c8
--- /dev/null
+++ b/libdiskfs/readonly.c
@@ -0,0 +1,111 @@
+/* Change to/from read-only
+
+   Copyright (C) 1995, 1996, 1997, 1999 Free Software Foundation, Inc.
+
+   Written by Miles Bader <miles@gnu.ai.mit.edu>
+
+   This file is part of the GNU Hurd.
+
+   The GNU Hurd is free software; you can redistribute it and/or
+   modify it under the terms of the GNU General Public License as
+   published by the Free Software Foundation; either version 2, or (at
+   your option) any later version.
+
+   The GNU Hurd is distributed in the hope that it will be useful, but
+   WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
+
+#include <fcntl.h>
+#include <error.h>
+
+#include "priv.h"
+
+int _diskfs_diskdirty;
+int diskfs_readonly = 0;
+int diskfs_hard_readonly = 0;
+
+int
+diskfs_check_readonly ()
+{
+  error_t err;
+
+  if (diskfs_readonly)
+    return 1;
+  else
+    {
+      if (!_diskfs_diskdirty)
+	{
+	  err = diskfs_set_hypermetadata (1, 0);
+	  if (err)
+	    {
+	      error (0, 0,
+		     "%s: MEDIA NOT WRITABLE; switching to READ-ONLY",
+		     diskfs_disk_name ?: "-");
+	      diskfs_hard_readonly = diskfs_readonly = 1;
+	      return 1;
+	    }
+	  _diskfs_diskdirty = 1;
+	}
+      return 0;
+    }
+}
+
+/* Change an active filesystem between read-only and writable modes, setting
+   the global variable DISKFS_READONLY to reflect the current mode.  If an
+   error is returned, nothing will have changed.  The user should hold
+   DISKFS_FSYS_LOCK while calling this routine.  */
+error_t
+diskfs_set_readonly (int readonly)
+{
+  error_t err = 0;
+
+  if (diskfs_hard_readonly)
+    return readonly ? 0 : EROFS;
+
+  if (readonly != diskfs_readonly)
+    {
+      err = ports_inhibit_class_rpcs (diskfs_protid_class);
+      if (! err)
+	{
+	  if (readonly)
+	    {
+	      error_t peropen_writable (void *pi)
+		{
+		  struct protid *const cred = pi;
+		  return (cred->po->openstat & O_WRITE) ? EBUSY : 0;
+		}
+
+	      /* Any writable open files?  */
+	      err = ports_class_iterate (diskfs_protid_class,
+					 peropen_writable);
+
+	      /* Any writable pagers?  */
+	      if (!err && (diskfs_max_user_pager_prot () & VM_PROT_WRITE))
+		err = EBUSY;
+
+	      if (!err)
+		/* Sync */
+		{
+		  diskfs_sync_everything (1);
+		  diskfs_set_hypermetadata (1, 1);
+		  _diskfs_diskdirty = 0;
+		}
+	    }
+
+	  if (!err)
+	    {
+	      diskfs_readonly = readonly;
+	      diskfs_readonly_changed (readonly);
+	    }
+
+	  ports_resume_class_rpcs (diskfs_protid_class);
+	}
+    }
+
+  return err;
+}