1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /* -*- mode: c; c-basic-offset: 8; -*-
3 * vim: noexpandtab sw=8 ts=8 sts=0:
4 *
5 * stackglue.h
6 *
7 * Glue to the underlying cluster stack.
8 *
9 * Copyright (C) 2007 Oracle. All rights reserved.
10 */
11
12
13 #ifndef STACKGLUE_H
14 #define STACKGLUE_H
15
16 #include <linux/types.h>
17 #include <linux/list.h>
18 #include <linux/dlmconstants.h>
19
20 #include "dlm/dlmapi.h"
21 #include <linux/dlm.h>
22
23 /* Needed for plock-related prototypes */
24 struct file;
25 struct file_lock;
26
27 /*
28 * dlmconstants.h does not have a LOCAL flag. We hope to remove it
29 * some day, but right now we need it. Let's fake it. This value is larger
30 * than any flag in dlmconstants.h.
31 */
32 #define DLM_LKF_LOCAL 0x00100000
33
34 /*
35 * This shadows DLM_LOCKSPACE_LEN in fs/dlm/dlm_internal.h. That probably
36 * wants to be in a public header.
37 */
38 #define GROUP_NAME_MAX 64
39
40 /* This shadows OCFS2_CLUSTER_NAME_LEN */
41 #define CLUSTER_NAME_MAX 16
42
43
44 /*
45 * ocfs2_protocol_version changes when ocfs2 does something different in
46 * its inter-node behavior. See dlmglue.c for more information.
47 */
48 struct ocfs2_protocol_version {
49 u8 pv_major;
50 u8 pv_minor;
51 };
52
53 /*
54 * The dlm_lockstatus struct includes lvb space, but the dlm_lksb struct only
55 * has a pointer to separately allocated lvb space. This struct exists only to
56 * include in the lksb union to make space for a combined dlm_lksb and lvb.
57 */
58 struct fsdlm_lksb_plus_lvb {
59 struct dlm_lksb lksb;
60 char lvb[DLM_LVB_LEN];
61 };
62
63 /*
64 * A union of all lock status structures. We define it here so that the
65 * size of the union is known. Lock status structures are embedded in
66 * ocfs2 inodes.
67 */
68 struct ocfs2_cluster_connection;
69 struct ocfs2_dlm_lksb {
70 union {
71 struct dlm_lockstatus lksb_o2dlm;
72 struct dlm_lksb lksb_fsdlm;
73 struct fsdlm_lksb_plus_lvb padding;
74 };
75 struct ocfs2_cluster_connection *lksb_conn;
76 };
77
78 /*
79 * The ocfs2_locking_protocol defines the handlers called on ocfs2's behalf.
80 */
81 struct ocfs2_locking_protocol {
82 struct ocfs2_protocol_version lp_max_version;
83 void (*lp_lock_ast)(struct ocfs2_dlm_lksb *lksb);
84 void (*lp_blocking_ast)(struct ocfs2_dlm_lksb *lksb, int level);
85 void (*lp_unlock_ast)(struct ocfs2_dlm_lksb *lksb, int error);
86 };
87
88
89 /*
90 * A cluster connection. Mostly opaque to ocfs2, the connection holds
91 * state for the underlying stack. ocfs2 does use cc_version to determine
92 * locking compatibility.
93 */
94 struct ocfs2_cluster_connection {
95 char cc_name[GROUP_NAME_MAX + 1];
96 int cc_namelen;
97 char cc_cluster_name[CLUSTER_NAME_MAX + 1];
98 int cc_cluster_name_len;
99 struct ocfs2_protocol_version cc_version;
100 struct ocfs2_locking_protocol *cc_proto;
101 void (*cc_recovery_handler)(int node_num, void *recovery_data);
102 void *cc_recovery_data;
103 void *cc_lockspace;
104 void *cc_private;
105 };
106
107 /*
108 * Each cluster stack implements the stack operations structure. Not used
109 * in the ocfs2 code, the stackglue code translates generic cluster calls
110 * into stack operations.
111 */
112 struct ocfs2_stack_operations {
113 /*
114 * The fs code calls ocfs2_cluster_connect() to attach a new
115 * filesystem to the cluster stack. The ->connect() op is passed
116 * an ocfs2_cluster_connection with the name and recovery field
117 * filled in.
118 *
119 * The stack must set up any notification mechanisms and create
120 * the filesystem lockspace in the DLM. The lockspace should be
121 * stored on cc_lockspace. Any other information can be stored on
122 * cc_private.
123 *
124 * ->connect() must not return until it is guaranteed that
125 *
126 * - Node down notifications for the filesystem will be received
127 * and passed to conn->cc_recovery_handler().
128 * - Locking requests for the filesystem will be processed.
129 */
130 int (*connect)(struct ocfs2_cluster_connection *conn);
131
132 /*
133 * The fs code calls ocfs2_cluster_disconnect() when a filesystem
134 * no longer needs cluster services. All DLM locks have been
135 * dropped, and recovery notification is being ignored by the
136 * fs code. The stack must disengage from the DLM and discontinue
137 * recovery notification.
138 *
139 * Once ->disconnect() has returned, the connection structure will
140 * be freed. Thus, a stack must not return from ->disconnect()
141 * until it will no longer reference the conn pointer.
142 *
143 * Once this call returns, the stack glue will be dropping this
144 * connection's reference on the module.
145 */
146 int (*disconnect)(struct ocfs2_cluster_connection *conn);
147
148 /*
149 * ->this_node() returns the cluster's unique identifier for the
150 * local node.
151 */
152 int (*this_node)(struct ocfs2_cluster_connection *conn,
153 unsigned int *node);
154
155 /*
156 * Call the underlying dlm lock function. The ->dlm_lock()
157 * callback should convert the flags and mode as appropriate.
158 *
159 * ast and bast functions are not part of the call because the
160 * stack will likely want to wrap ast and bast calls before passing
161 * them to stack->sp_proto. There is no astarg. The lksb will
162 * be passed back to the ast and bast functions. The caller can
163 * use this to find their object.
164 */
165 int (*dlm_lock)(struct ocfs2_cluster_connection *conn,
166 int mode,
167 struct ocfs2_dlm_lksb *lksb,
168 u32 flags,
169 void *name,
170 unsigned int namelen);
171
172 /*
173 * Call the underlying dlm unlock function. The ->dlm_unlock()
174 * function should convert the flags as appropriate.
175 *
176 * The unlock ast is not passed, as the stack will want to wrap
177 * it before calling stack->sp_proto->lp_unlock_ast(). There is
178 * no astarg. The lksb will be passed back to the unlock ast
179 * function. The caller can use this to find their object.
180 */
181 int (*dlm_unlock)(struct ocfs2_cluster_connection *conn,
182 struct ocfs2_dlm_lksb *lksb,
183 u32 flags);
184
185 /*
186 * Return the status of the current lock status block. The fs
187 * code should never dereference the union. The ->lock_status()
188 * callback pulls out the stack-specific lksb, converts the status
189 * to a proper errno, and returns it.
190 */
191 int (*lock_status)(struct ocfs2_dlm_lksb *lksb);
192
193 /*
194 * Return non-zero if the LVB is valid.
195 */
196 int (*lvb_valid)(struct ocfs2_dlm_lksb *lksb);
197
198 /*
199 * Pull the lvb pointer off of the stack-specific lksb.
200 */
201 void *(*lock_lvb)(struct ocfs2_dlm_lksb *lksb);
202
203 /*
204 * Cluster-aware posix locks
205 *
206 * This is NULL for stacks which do not support posix locks.
207 */
208 int (*plock)(struct ocfs2_cluster_connection *conn,
209 u64 ino,
210 struct file *file,
211 int cmd,
212 struct file_lock *fl);
213
214 /*
215 * This is an optoinal debugging hook. If provided, the
216 * stack can dump debugging information about this lock.
217 */
218 void (*dump_lksb)(struct ocfs2_dlm_lksb *lksb);
219 };
220
221 /*
222 * Each stack plugin must describe itself by registering a
223 * ocfs2_stack_plugin structure. This is only seen by stackglue and the
224 * stack driver.
225 */
226 struct ocfs2_stack_plugin {
227 char *sp_name;
228 struct ocfs2_stack_operations *sp_ops;
229 struct module *sp_owner;
230
231 /* These are managed by the stackglue code. */
232 struct list_head sp_list;
233 unsigned int sp_count;
234 struct ocfs2_protocol_version sp_max_proto;
235 };
236
237
238 /* Used by the filesystem */
239 int ocfs2_cluster_connect(const char *stack_name,
240 const char *cluster_name,
241 int cluster_name_len,
242 const char *group,
243 int grouplen,
244 struct ocfs2_locking_protocol *lproto,
245 void (*recovery_handler)(int node_num,
246 void *recovery_data),
247 void *recovery_data,
248 struct ocfs2_cluster_connection **conn);
249 /*
250 * Used by callers that don't store their stack name. They must ensure
251 * all nodes have the same stack.
252 */
253 int ocfs2_cluster_connect_agnostic(const char *group,
254 int grouplen,
255 struct ocfs2_locking_protocol *lproto,
256 void (*recovery_handler)(int node_num,
257 void *recovery_data),
258 void *recovery_data,
259 struct ocfs2_cluster_connection **conn);
260 int ocfs2_cluster_disconnect(struct ocfs2_cluster_connection *conn,
261 int hangup_pending);
262 void ocfs2_cluster_hangup(const char *group, int grouplen);
263 int ocfs2_cluster_this_node(struct ocfs2_cluster_connection *conn,
264 unsigned int *node);
265
266 struct ocfs2_lock_res;
267 int ocfs2_dlm_lock(struct ocfs2_cluster_connection *conn,
268 int mode,
269 struct ocfs2_dlm_lksb *lksb,
270 u32 flags,
271 void *name,
272 unsigned int namelen);
273 int ocfs2_dlm_unlock(struct ocfs2_cluster_connection *conn,
274 struct ocfs2_dlm_lksb *lksb,
275 u32 flags);
276
277 int ocfs2_dlm_lock_status(struct ocfs2_dlm_lksb *lksb);
278 int ocfs2_dlm_lvb_valid(struct ocfs2_dlm_lksb *lksb);
279 void *ocfs2_dlm_lvb(struct ocfs2_dlm_lksb *lksb);
280 void ocfs2_dlm_dump_lksb(struct ocfs2_dlm_lksb *lksb);
281
282 int ocfs2_stack_supports_plocks(void);
283 int ocfs2_plock(struct ocfs2_cluster_connection *conn, u64 ino,
284 struct file *file, int cmd, struct file_lock *fl);
285
286 void ocfs2_stack_glue_set_max_proto_version(struct ocfs2_protocol_version *max_proto);
287
288
289 /* Used by stack plugins */
290 int ocfs2_stack_glue_register(struct ocfs2_stack_plugin *plugin);
291 void ocfs2_stack_glue_unregister(struct ocfs2_stack_plugin *plugin);
292
293 extern struct kset *ocfs2_kset;
294
295 #endif /* STACKGLUE_H */