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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 | /* Needed for plock-related prototypes */ | |
32 | struct file; | |
33 | struct file_lock; | |
34 | ||
35 | /* | |
36 | * dlmconstants.h does not have a LOCAL flag. We hope to remove it | |
37 | * some day, but right now we need it. Let's fake it. This value is larger | |
38 | * than any flag in dlmconstants.h. | |
39 | */ | |
40 | #define DLM_LKF_LOCAL 0x00100000 | |
41 | ||
42 | /* | |
43 | * This shadows DLM_LOCKSPACE_LEN in fs/dlm/dlm_internal.h. That probably | |
44 | * wants to be in a public header. | |
45 | */ | |
46 | #define GROUP_NAME_MAX 64 | |
47 | ||
48 | /* This shadows OCFS2_CLUSTER_NAME_LEN */ | |
49 | #define CLUSTER_NAME_MAX 16 | |
50 | ||
51 | ||
52 | /* | |
53 | * ocfs2_protocol_version changes when ocfs2 does something different in | |
54 | * its inter-node behavior. See dlmglue.c for more information. | |
55 | */ | |
56 | struct ocfs2_protocol_version { | |
57 | u8 pv_major; | |
58 | u8 pv_minor; | |
59 | }; | |
60 | ||
61 | /* | |
62 | * The dlm_lockstatus struct includes lvb space, but the dlm_lksb struct only | |
63 | * has a pointer to separately allocated lvb space. This struct exists only to | |
64 | * include in the lksb union to make space for a combined dlm_lksb and lvb. | |
65 | */ | |
66 | struct fsdlm_lksb_plus_lvb { | |
67 | struct dlm_lksb lksb; | |
68 | char lvb[DLM_LVB_LEN]; | |
69 | }; | |
70 | ||
71 | /* | |
72 | * A union of all lock status structures. We define it here so that the | |
73 | * size of the union is known. Lock status structures are embedded in | |
74 | * ocfs2 inodes. | |
75 | */ | |
76 | struct ocfs2_cluster_connection; | |
77 | struct ocfs2_dlm_lksb { | |
78 | union { | |
79 | struct dlm_lockstatus lksb_o2dlm; | |
80 | struct dlm_lksb lksb_fsdlm; | |
81 | struct fsdlm_lksb_plus_lvb padding; | |
82 | }; | |
83 | struct ocfs2_cluster_connection *lksb_conn; | |
84 | }; | |
85 | ||
86 | /* | |
87 | * The ocfs2_locking_protocol defines the handlers called on ocfs2's behalf. | |
88 | */ | |
89 | struct ocfs2_locking_protocol { | |
90 | struct ocfs2_protocol_version lp_max_version; | |
91 | void (*lp_lock_ast)(struct ocfs2_dlm_lksb *lksb); | |
92 | void (*lp_blocking_ast)(struct ocfs2_dlm_lksb *lksb, int level); | |
93 | void (*lp_unlock_ast)(struct ocfs2_dlm_lksb *lksb, int error); | |
94 | }; | |
95 | ||
96 | ||
97 | /* | |
98 | * A cluster connection. Mostly opaque to ocfs2, the connection holds | |
99 | * state for the underlying stack. ocfs2 does use cc_version to determine | |
100 | * locking compatibility. | |
101 | */ | |
102 | struct ocfs2_cluster_connection { | |
103 | char cc_name[GROUP_NAME_MAX + 1]; | |
104 | int cc_namelen; | |
105 | char cc_cluster_name[CLUSTER_NAME_MAX + 1]; | |
106 | int cc_cluster_name_len; | |
107 | struct ocfs2_protocol_version cc_version; | |
108 | struct ocfs2_locking_protocol *cc_proto; | |
109 | void (*cc_recovery_handler)(int node_num, void *recovery_data); | |
110 | void *cc_recovery_data; | |
111 | void *cc_lockspace; | |
112 | void *cc_private; | |
113 | }; | |
114 | ||
115 | /* | |
116 | * Each cluster stack implements the stack operations structure. Not used | |
117 | * in the ocfs2 code, the stackglue code translates generic cluster calls | |
118 | * into stack operations. | |
119 | */ | |
120 | struct ocfs2_stack_operations { | |
121 | /* | |
122 | * The fs code calls ocfs2_cluster_connect() to attach a new | |
123 | * filesystem to the cluster stack. The ->connect() op is passed | |
124 | * an ocfs2_cluster_connection with the name and recovery field | |
125 | * filled in. | |
126 | * | |
127 | * The stack must set up any notification mechanisms and create | |
128 | * the filesystem lockspace in the DLM. The lockspace should be | |
129 | * stored on cc_lockspace. Any other information can be stored on | |
130 | * cc_private. | |
131 | * | |
132 | * ->connect() must not return until it is guaranteed that | |
133 | * | |
134 | * - Node down notifications for the filesystem will be received | |
135 | * and passed to conn->cc_recovery_handler(). | |
136 | * - Locking requests for the filesystem will be processed. | |
137 | */ | |
138 | int (*connect)(struct ocfs2_cluster_connection *conn); | |
139 | ||
140 | /* | |
141 | * The fs code calls ocfs2_cluster_disconnect() when a filesystem | |
142 | * no longer needs cluster services. All DLM locks have been | |
143 | * dropped, and recovery notification is being ignored by the | |
144 | * fs code. The stack must disengage from the DLM and discontinue | |
145 | * recovery notification. | |
146 | * | |
147 | * Once ->disconnect() has returned, the connection structure will | |
148 | * be freed. Thus, a stack must not return from ->disconnect() | |
149 | * until it will no longer reference the conn pointer. | |
150 | * | |
151 | * Once this call returns, the stack glue will be dropping this | |
152 | * connection's reference on the module. | |
153 | */ | |
154 | int (*disconnect)(struct ocfs2_cluster_connection *conn); | |
155 | ||
156 | /* | |
157 | * ->this_node() returns the cluster's unique identifier for the | |
158 | * local node. | |
159 | */ | |
160 | int (*this_node)(struct ocfs2_cluster_connection *conn, | |
161 | unsigned int *node); | |
162 | ||
163 | /* | |
164 | * Call the underlying dlm lock function. The ->dlm_lock() | |
165 | * callback should convert the flags and mode as appropriate. | |
166 | * | |
167 | * ast and bast functions are not part of the call because the | |
168 | * stack will likely want to wrap ast and bast calls before passing | |
169 | * them to stack->sp_proto. There is no astarg. The lksb will | |
170 | * be passed back to the ast and bast functions. The caller can | |
171 | * use this to find their object. | |
172 | */ | |
173 | int (*dlm_lock)(struct ocfs2_cluster_connection *conn, | |
174 | int mode, | |
175 | struct ocfs2_dlm_lksb *lksb, | |
176 | u32 flags, | |
177 | void *name, | |
178 | unsigned int namelen); | |
179 | ||
180 | /* | |
181 | * Call the underlying dlm unlock function. The ->dlm_unlock() | |
182 | * function should convert the flags as appropriate. | |
183 | * | |
184 | * The unlock ast is not passed, as the stack will want to wrap | |
185 | * it before calling stack->sp_proto->lp_unlock_ast(). There is | |
186 | * no astarg. The lksb will be passed back to the unlock ast | |
187 | * function. The caller can use this to find their object. | |
188 | */ | |
189 | int (*dlm_unlock)(struct ocfs2_cluster_connection *conn, | |
190 | struct ocfs2_dlm_lksb *lksb, | |
191 | u32 flags); | |
192 | ||
193 | /* | |
194 | * Return the status of the current lock status block. The fs | |
195 | * code should never dereference the union. The ->lock_status() | |
196 | * callback pulls out the stack-specific lksb, converts the status | |
197 | * to a proper errno, and returns it. | |
198 | */ | |
199 | int (*lock_status)(struct ocfs2_dlm_lksb *lksb); | |
200 | ||
201 | /* | |
202 | * Return non-zero if the LVB is valid. | |
203 | */ | |
204 | int (*lvb_valid)(struct ocfs2_dlm_lksb *lksb); | |
205 | ||
206 | /* | |
207 | * Pull the lvb pointer off of the stack-specific lksb. | |
208 | */ | |
209 | void *(*lock_lvb)(struct ocfs2_dlm_lksb *lksb); | |
210 | ||
211 | /* | |
212 | * Cluster-aware posix locks | |
213 | * | |
214 | * This is NULL for stacks which do not support posix locks. | |
215 | */ | |
216 | int (*plock)(struct ocfs2_cluster_connection *conn, | |
217 | u64 ino, | |
218 | struct file *file, | |
219 | int cmd, | |
220 | struct file_lock *fl); | |
221 | ||
222 | /* | |
223 | * This is an optoinal debugging hook. If provided, the | |
224 | * stack can dump debugging information about this lock. | |
225 | */ | |
226 | void (*dump_lksb)(struct ocfs2_dlm_lksb *lksb); | |
227 | }; | |
228 | ||
229 | /* | |
230 | * Each stack plugin must describe itself by registering a | |
231 | * ocfs2_stack_plugin structure. This is only seen by stackglue and the | |
232 | * stack driver. | |
233 | */ | |
234 | struct ocfs2_stack_plugin { | |
235 | char *sp_name; | |
236 | struct ocfs2_stack_operations *sp_ops; | |
237 | struct module *sp_owner; | |
238 | ||
239 | /* These are managed by the stackglue code. */ | |
240 | struct list_head sp_list; | |
241 | unsigned int sp_count; | |
242 | struct ocfs2_protocol_version sp_max_proto; | |
243 | }; | |
244 | ||
245 | ||
246 | /* Used by the filesystem */ | |
247 | int ocfs2_cluster_connect(const char *stack_name, | |
248 | const char *cluster_name, | |
249 | int cluster_name_len, | |
250 | const char *group, | |
251 | int grouplen, | |
252 | struct ocfs2_locking_protocol *lproto, | |
253 | void (*recovery_handler)(int node_num, | |
254 | void *recovery_data), | |
255 | void *recovery_data, | |
256 | struct ocfs2_cluster_connection **conn); | |
257 | /* | |
258 | * Used by callers that don't store their stack name. They must ensure | |
259 | * all nodes have the same stack. | |
260 | */ | |
261 | int ocfs2_cluster_connect_agnostic(const char *group, | |
262 | int grouplen, | |
263 | struct ocfs2_locking_protocol *lproto, | |
264 | void (*recovery_handler)(int node_num, | |
265 | void *recovery_data), | |
266 | void *recovery_data, | |
267 | struct ocfs2_cluster_connection **conn); | |
268 | int ocfs2_cluster_disconnect(struct ocfs2_cluster_connection *conn, | |
269 | int hangup_pending); | |
270 | void ocfs2_cluster_hangup(const char *group, int grouplen); | |
271 | int ocfs2_cluster_this_node(struct ocfs2_cluster_connection *conn, | |
272 | unsigned int *node); | |
273 | ||
274 | struct ocfs2_lock_res; | |
275 | int ocfs2_dlm_lock(struct ocfs2_cluster_connection *conn, | |
276 | int mode, | |
277 | struct ocfs2_dlm_lksb *lksb, | |
278 | u32 flags, | |
279 | void *name, | |
280 | unsigned int namelen); | |
281 | int ocfs2_dlm_unlock(struct ocfs2_cluster_connection *conn, | |
282 | struct ocfs2_dlm_lksb *lksb, | |
283 | u32 flags); | |
284 | ||
285 | int ocfs2_dlm_lock_status(struct ocfs2_dlm_lksb *lksb); | |
286 | int ocfs2_dlm_lvb_valid(struct ocfs2_dlm_lksb *lksb); | |
287 | void *ocfs2_dlm_lvb(struct ocfs2_dlm_lksb *lksb); | |
288 | void ocfs2_dlm_dump_lksb(struct ocfs2_dlm_lksb *lksb); | |
289 | ||
290 | int ocfs2_stack_supports_plocks(void); | |
291 | int ocfs2_plock(struct ocfs2_cluster_connection *conn, u64 ino, | |
292 | struct file *file, int cmd, struct file_lock *fl); | |
293 | ||
294 | void ocfs2_stack_glue_set_max_proto_version(struct ocfs2_protocol_version *max_proto); | |
295 | ||
296 | ||
297 | /* Used by stack plugins */ | |
298 | int ocfs2_stack_glue_register(struct ocfs2_stack_plugin *plugin); | |
299 | void ocfs2_stack_glue_unregister(struct ocfs2_stack_plugin *plugin); | |
300 | ||
301 | extern struct kset *ocfs2_kset; | |
302 | ||
303 | #endif /* STACKGLUE_H */ |