[Ocfs2-tools-commits] mfasheh commits r538 - trunk/libo2cb/include

[svn-commits at oss.oracle.com]

Author: mfasheh
Date: 2005-01-05 16:12:17 -0600 (Wed, 05 Jan 2005)
New Revision: 538

Added:
   trunk/libo2cb/include/o2cb_dlm.h
Log:
* basic stubs for what will becomes our userspace->kernel dlm api.



Added: trunk/libo2cb/include/o2cb_dlm.h
===================================================================
--- trunk/libo2cb/include/o2cb_dlm.h	2005-01-05 20:58:31 UTC (rev 537)
+++ trunk/libo2cb/include/o2cb_dlm.h	2005-01-05 22:12:17 UTC (rev 538)
@@ -0,0 +1,127 @@
+/* -*- mode: c; c-basic-offset: 8; -*-
+ * vim: noexpandtab sw=8 ts=8 sts=0:
+ *
+ * o2cb_dlm.h
+ *
+ * Defines the userspace locking api
+ *
+ * Copyright (C) 2004 Oracle.  All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License, version 2,  as published by the Free Software Foundation.
+ * 
+ * This program 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., 59 Temple Place - Suite 330,
+ * Boston, MA 021110-1307, USA.
+ */
+
+#ifndef _O2CB_DLM_H_
+#define _O2CB_DLM_H_
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+
+/* this is the top-level dir containing all the lock "files" I don't
+   really expect it will end up being in this exact place */
+#define O2CB_USER_DLM_LOCK_PATH    "/dev/ocfs2/dlm/"
+#define O2CB_LOCK_ID_MAX_LEN       32
+#define O2CB_DLM_OPEN_MODE         0664
+
+/* need to pull in the userland list.h header for this */
+struct o2cb_dlm_lock_ctxt
+{
+	struct list_head ct_locks;  /* the ordered list of locks */
+};
+
+/* valid lock flags */
+#define O2CB_DLM_TRYLOCK      O_NONBLOCK
+
+/* valid lock levels */
+enum o2cb_lock_level
+{
+	O2CB_DLM_LEVEL_PRMODE,
+	O2CB_DLM_LEVEL_EXMODE
+};
+
+struct o2cb_lock
+{
+	struct list_head     l_list;  /* to hang us off the locks list */
+	char                 *l_id;   /* 32 byte, null terminated string */
+	int                  l_flags; /* limited set of flags */
+	enum o2cb_lock_level l_level; /* either PR or EX */
+	int                  l_fd;    /* the fd returned by the open call */
+};
+
+
+/*
+ *  Should this be called by the lib on the first init call
+ *  or should it be called directly by the program (fsck, etc)
+ *  when it tries to start up?  Or should this whole task be 
+ *  done in an init script?  
+ *  
+ *  This function needs to load the userdlm.o module
+ *  and mount its pseudo-fs in some location.  Anything else???
+ *
+ *  Returns:  0 on success
+ *            -EIO if the fs isn't ready
+ */     
+int o2cb_dlm_mount(void);
+
+/*
+ * This should malloc a o2cb_dlm_lock_ctxt and init the locks
+ * list_head
+ *
+ * Returns: 0 on success
+ *          -ENOMEM if we couldn't malloc
+ */
+o2cb_dlm_lock_ctxt * o2cb_dlm_initialize(void);
+
+/*
+ * Takes a valid o2cb_dlm_lock_ctxt and lockid and attempts to
+ * open("O2CB_DLM_LOCK_PATH/lockid", flags|level|O_CREAT, mode).
+ * Validates the id, flags, and level as best it can.
+ * Mallocs one new o2cb_lock and stuffs the id, flags, level,
+ * and new lock_fd into it, then list_add_tail's it to the end
+ * of the supplied ctxt.
+ *
+ * lock_name, is a valid ocfs2 lock name -- 32 bytes long, null terminated.
+ *
+ * Returns: 0 if we got the lock we wanted
+ *          -ENOMEM if we couldn't malloc
+ *          -EIO if you never did a prepare()
+ *          -EBUSY if flags==O2CB_DLM_TRYLOCK and we didn't get the lock
+ *          -EINVAL if any of the 3 params was bad
+ */
+int o2cb_dlm_lock(o2cb_dlm_lock_ctxt *ctxt,
+		  char *lockid,
+		  int flags,
+		  enum o2cb_lock_level level);
+
+/* 
+ * Looks up the lock id in your ctxt->locks list.
+ * If found, calls close(lock_fd) and frees the o2cb_lock
+ *
+ * Returns: 0 on success 
+ *          -EINVAL if the ctxt or ino is bad
+ */
+int o2cb_dlm_unlock(o2cb_dlm_lock_ctxt *ctxt,
+		    char *lockid);
+
+/*
+ * Frees the lock context
+ * 
+ * Returns: 0 on success
+ *          -EBUSY if there are still locks remaining on the list
+ *          -EINVAL if ctxt is bad
+ */
+int o2cb_dlm_destroy(o2cb_dlm_lock_ctxt *ctxt);
+
+#endif /* _O2CB_DLM_H_ */