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1/* -*- mode: c; c-basic-offset: 8; -*-
2 * vim: noexpandtab sw=8 ts=8 sts=0:
3 *
4 * stackglue.h
5 *
6 * Glue to the underlying cluster stack.
7 *
8 * Copyright (C) 2007 Oracle. All rights reserved.
9 *
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public
12 * License as published by the Free Software Foundation, version 2.
13 *
14 * This program is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17 * General Public License for more details.
18 */
19
20
21#ifndef STACKGLUE_H
22#define STACKGLUE_H
23
24#include <linux/types.h>
25#include <linux/list.h>
26#include <linux/dlmconstants.h>
27
28#include "dlm/dlmapi.h"
29#include <linux/dlm.h>
30
31/*
32 * dlmconstants.h does not have a LOCAL flag. We hope to remove it
33 * some day, but right now we need it. Let's fake it. This value is larger
34 * than any flag in dlmconstants.h.
35 */
36#define DLM_LKF_LOCAL 0x00100000
37
38/*
39 * This shadows DLM_LOCKSPACE_LEN in fs/dlm/dlm_internal.h. That probably
40 * wants to be in a public header.
41 */
42#define GROUP_NAME_MAX 64
43
44
45/*
46 * ocfs2_protocol_version changes when ocfs2 does something different in
47 * its inter-node behavior. See dlmglue.c for more information.
48 */
49struct ocfs2_protocol_version {
50 u8 pv_major;
51 u8 pv_minor;
52};
53
54/*
55 * The ocfs2_locking_protocol defines the handlers called on ocfs2's behalf.
56 */
57struct ocfs2_locking_protocol {
58 struct ocfs2_protocol_version lp_max_version;
59 void (*lp_lock_ast)(void *astarg);
60 void (*lp_blocking_ast)(void *astarg, int level);
61 void (*lp_unlock_ast)(void *astarg, int error);
62};
63
64
65/*
66 * The dlm_lockstatus struct includes lvb space, but the dlm_lksb struct only
67 * has a pointer to separately allocated lvb space. This struct exists only to
68 * include in the lksb union to make space for a combined dlm_lksb and lvb.
69 */
70struct fsdlm_lksb_plus_lvb {
71 struct dlm_lksb lksb;
72 char lvb[DLM_LVB_LEN];
73};
74
75/*
76 * A union of all lock status structures. We define it here so that the
77 * size of the union is known. Lock status structures are embedded in
78 * ocfs2 inodes.
79 */
80union ocfs2_dlm_lksb {
81 struct dlm_lockstatus lksb_o2dlm;
82 struct dlm_lksb lksb_fsdlm;
83 struct fsdlm_lksb_plus_lvb padding;
84};
85
86/*
87 * A cluster connection. Mostly opaque to ocfs2, the connection holds
88 * state for the underlying stack. ocfs2 does use cc_version to determine
89 * locking compatibility.
90 */
91struct ocfs2_cluster_connection {
92 char cc_name[GROUP_NAME_MAX];
93 int cc_namelen;
94 struct ocfs2_protocol_version cc_version;
95 void (*cc_recovery_handler)(int node_num, void *recovery_data);
96 void *cc_recovery_data;
97 void *cc_lockspace;
98 void *cc_private;
99};
100
101/*
102 * Each cluster stack implements the stack operations structure. Not used
103 * in the ocfs2 code, the stackglue code translates generic cluster calls
104 * into stack operations.
105 */
106struct ocfs2_stack_operations {
107 /*
108 * The fs code calls ocfs2_cluster_connect() to attach a new
109 * filesystem to the cluster stack. The ->connect() op is passed
110 * an ocfs2_cluster_connection with the name and recovery field
111 * filled in.
112 *
113 * The stack must set up any notification mechanisms and create
114 * the filesystem lockspace in the DLM. The lockspace should be
115 * stored on cc_lockspace. Any other information can be stored on
116 * cc_private.
117 *
118 * ->connect() must not return until it is guaranteed that
119 *
120 * - Node down notifications for the filesystem will be recieved
121 * and passed to conn->cc_recovery_handler().
122 * - Locking requests for the filesystem will be processed.
123 */
124 int (*connect)(struct ocfs2_cluster_connection *conn);
125
126 /*
127 * The fs code calls ocfs2_cluster_disconnect() when a filesystem
128 * no longer needs cluster services. All DLM locks have been
129 * dropped, and recovery notification is being ignored by the
130 * fs code. The stack must disengage from the DLM and discontinue
131 * recovery notification.
132 *
133 * Once ->disconnect() has returned, the connection structure will
134 * be freed. Thus, a stack must not return from ->disconnect()
135 * until it will no longer reference the conn pointer.
136 *
137 * If hangup_pending is zero, ocfs2_cluster_disconnect() will also
138 * be dropping the reference on the module.
139 */
140 int (*disconnect)(struct ocfs2_cluster_connection *conn,
141 int hangup_pending);
142
143 /*
144 * ocfs2_cluster_hangup() exists for compatibility with older
145 * ocfs2 tools. Only the classic stack really needs it. As such
146 * ->hangup() is not required of all stacks. See the comment by
147 * ocfs2_cluster_hangup() for more details.
148 *
149 * Note that ocfs2_cluster_hangup() can only be called if
150 * hangup_pending was passed to ocfs2_cluster_disconnect().
151 */
152 void (*hangup)(const char *group, int grouplen);
153
154 /*
155 * ->this_node() returns the cluster's unique identifier for the
156 * local node.
157 */
158 int (*this_node)(unsigned int *node);
159
160 /*
161 * Call the underlying dlm lock function. The ->dlm_lock()
162 * callback should convert the flags and mode as appropriate.
163 *
164 * ast and bast functions are not part of the call because the
165 * stack will likely want to wrap ast and bast calls before passing
166 * them to stack->sp_proto.
167 */
168 int (*dlm_lock)(struct ocfs2_cluster_connection *conn,
169 int mode,
170 union ocfs2_dlm_lksb *lksb,
171 u32 flags,
172 void *name,
173 unsigned int namelen,
174 void *astarg);
175
176 /*
177 * Call the underlying dlm unlock function. The ->dlm_unlock()
178 * function should convert the flags as appropriate.
179 *
180 * The unlock ast is not passed, as the stack will want to wrap
181 * it before calling stack->sp_proto->lp_unlock_ast().
182 */
183 int (*dlm_unlock)(struct ocfs2_cluster_connection *conn,
184 union ocfs2_dlm_lksb *lksb,
185 u32 flags,
186 void *astarg);
187
188 /*
189 * Return the status of the current lock status block. The fs
190 * code should never dereference the union. The ->lock_status()
191 * callback pulls out the stack-specific lksb, converts the status
192 * to a proper errno, and returns it.
193 */
194 int (*lock_status)(union ocfs2_dlm_lksb *lksb);
195
196 /*
197 * Pull the lvb pointer off of the stack-specific lksb.
198 */
199 void *(*lock_lvb)(union ocfs2_dlm_lksb *lksb);
200
201 /*
202 * This is an optoinal debugging hook. If provided, the
203 * stack can dump debugging information about this lock.
204 */
205 void (*dump_lksb)(union ocfs2_dlm_lksb *lksb);
206};
207
208/*
209 * Each stack plugin must describe itself by registering a
210 * ocfs2_stack_plugin structure. This is only seen by stackglue and the
211 * stack driver.
212 */
213struct ocfs2_stack_plugin {
214 char *sp_name;
215 struct ocfs2_stack_operations *sp_ops;
216 struct module *sp_owner;
217
218 /* These are managed by the stackglue code. */
219 struct list_head sp_list;
220 unsigned int sp_count;
221 struct ocfs2_locking_protocol *sp_proto;
222};
223
224
225/* Used by the filesystem */
226int ocfs2_cluster_connect(const char *stack_name,
227 const char *group,
228 int grouplen,
229 void (*recovery_handler)(int node_num,
230 void *recovery_data),
231 void *recovery_data,
232 struct ocfs2_cluster_connection **conn);
233int ocfs2_cluster_disconnect(struct ocfs2_cluster_connection *conn,
234 int hangup_pending);
235void ocfs2_cluster_hangup(const char *group, int grouplen);
236int ocfs2_cluster_this_node(unsigned int *node);
237
238struct ocfs2_lock_res;
239int ocfs2_dlm_lock(struct ocfs2_cluster_connection *conn,
240 int mode,
241 union ocfs2_dlm_lksb *lksb,
242 u32 flags,
243 void *name,
244 unsigned int namelen,
245 struct ocfs2_lock_res *astarg);
246int ocfs2_dlm_unlock(struct ocfs2_cluster_connection *conn,
247 union ocfs2_dlm_lksb *lksb,
248 u32 flags,
249 struct ocfs2_lock_res *astarg);
250
251int ocfs2_dlm_lock_status(union ocfs2_dlm_lksb *lksb);
252void *ocfs2_dlm_lvb(union ocfs2_dlm_lksb *lksb);
253void ocfs2_dlm_dump_lksb(union ocfs2_dlm_lksb *lksb);
254
255void ocfs2_stack_glue_set_locking_protocol(struct ocfs2_locking_protocol *proto);
256
257
258/* Used by stack plugins */
259int ocfs2_stack_glue_register(struct ocfs2_stack_plugin *plugin);
260void ocfs2_stack_glue_unregister(struct ocfs2_stack_plugin *plugin);
261#endif /* STACKGLUE_H */