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