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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 | |
49 | /* |
50 | * ocfs2_protocol_version changes when ocfs2 does something different in |
51 | * its inter-node behavior. See dlmglue.c for more information. |
52 | */ |
53 | struct ocfs2_protocol_version { |
54 | u8 pv_major; |
55 | u8 pv_minor; |
56 | }; |
57 | |
58 | /* |
59 | * The ocfs2_locking_protocol defines the handlers called on ocfs2's behalf. |
60 | */ |
61 | struct ocfs2_locking_protocol { |
62 | struct ocfs2_protocol_version lp_max_version; |
63 | void (*lp_lock_ast)(void *astarg); |
64 | void (*lp_blocking_ast)(void *astarg, int level); |
65 | void (*lp_unlock_ast)(void *astarg, int error); |
66 | }; |
67 | |
68 | |
69 | /* |
70 | * The dlm_lockstatus struct includes lvb space, but the dlm_lksb struct only |
71 | * has a pointer to separately allocated lvb space. This struct exists only to |
72 | * include in the lksb union to make space for a combined dlm_lksb and lvb. |
73 | */ |
74 | struct fsdlm_lksb_plus_lvb { |
75 | struct dlm_lksb lksb; |
76 | char lvb[DLM_LVB_LEN]; |
77 | }; |
78 | |
79 | /* |
80 | * A union of all lock status structures. We define it here so that the |
81 | * size of the union is known. Lock status structures are embedded in |
82 | * ocfs2 inodes. |
83 | */ |
84 | union ocfs2_dlm_lksb { |
85 | struct dlm_lockstatus lksb_o2dlm; |
86 | struct dlm_lksb lksb_fsdlm; |
87 | struct fsdlm_lksb_plus_lvb padding; |
88 | }; |
89 | |
90 | /* |
91 | * A cluster connection. Mostly opaque to ocfs2, the connection holds |
92 | * state for the underlying stack. ocfs2 does use cc_version to determine |
93 | * locking compatibility. |
94 | */ |
95 | struct ocfs2_cluster_connection { |
96 | char cc_name[GROUP_NAME_MAX]; |
97 | int cc_namelen; |
98 | struct ocfs2_protocol_version cc_version; |
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 recieved |
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)(unsigned int *node); |
151 | |
152 | /* |
153 | * Call the underlying dlm lock function. The ->dlm_lock() |
154 | * callback should convert the flags and mode as appropriate. |
155 | * |
156 | * ast and bast functions are not part of the call because the |
157 | * stack will likely want to wrap ast and bast calls before passing |
158 | * them to stack->sp_proto. |
159 | */ |
160 | int (*dlm_lock)(struct ocfs2_cluster_connection *conn, |
161 | int mode, |
162 | union ocfs2_dlm_lksb *lksb, |
163 | u32 flags, |
164 | void *name, |
165 | unsigned int namelen, |
166 | void *astarg); |
167 | |
168 | /* |
169 | * Call the underlying dlm unlock function. The ->dlm_unlock() |
170 | * function should convert the flags as appropriate. |
171 | * |
172 | * The unlock ast is not passed, as the stack will want to wrap |
173 | * it before calling stack->sp_proto->lp_unlock_ast(). |
174 | */ |
175 | int (*dlm_unlock)(struct ocfs2_cluster_connection *conn, |
176 | union ocfs2_dlm_lksb *lksb, |
177 | u32 flags, |
178 | void *astarg); |
179 | |
180 | /* |
181 | * Return the status of the current lock status block. The fs |
182 | * code should never dereference the union. The ->lock_status() |
183 | * callback pulls out the stack-specific lksb, converts the status |
184 | * to a proper errno, and returns it. |
185 | */ |
186 | int (*lock_status)(union ocfs2_dlm_lksb *lksb); |
187 | |
188 | /* |
189 | * Return non-zero if the LVB is valid. |
190 | */ |
191 | int (*lvb_valid)(union ocfs2_dlm_lksb *lksb); |
192 | |
193 | /* |
194 | * Pull the lvb pointer off of the stack-specific lksb. |
195 | */ |
196 | void *(*lock_lvb)(union ocfs2_dlm_lksb *lksb); |
197 | |
198 | /* |
199 | * Cluster-aware posix locks |
200 | * |
201 | * This is NULL for stacks which do not support posix locks. |
202 | */ |
203 | int (*plock)(struct ocfs2_cluster_connection *conn, |
204 | u64 ino, |
205 | struct file *file, |
206 | int cmd, |
207 | struct file_lock *fl); |
208 | |
209 | /* |
210 | * This is an optoinal debugging hook. If provided, the |
211 | * stack can dump debugging information about this lock. |
212 | */ |
213 | void (*dump_lksb)(union ocfs2_dlm_lksb *lksb); |
214 | }; |
215 | |
216 | /* |
217 | * Each stack plugin must describe itself by registering a |
218 | * ocfs2_stack_plugin structure. This is only seen by stackglue and the |
219 | * stack driver. |
220 | */ |
221 | struct ocfs2_stack_plugin { |
222 | char *sp_name; |
223 | struct ocfs2_stack_operations *sp_ops; |
224 | struct module *sp_owner; |
225 | |
226 | /* These are managed by the stackglue code. */ |
227 | struct list_head sp_list; |
228 | unsigned int sp_count; |
229 | struct ocfs2_locking_protocol *sp_proto; |
230 | }; |
231 | |
232 | |
233 | /* Used by the filesystem */ |
234 | int ocfs2_cluster_connect(const char *stack_name, |
235 | const char *group, |
236 | int grouplen, |
237 | void (*recovery_handler)(int node_num, |
238 | void *recovery_data), |
239 | void *recovery_data, |
240 | struct ocfs2_cluster_connection **conn); |
241 | int ocfs2_cluster_disconnect(struct ocfs2_cluster_connection *conn, |
242 | int hangup_pending); |
243 | void ocfs2_cluster_hangup(const char *group, int grouplen); |
244 | int ocfs2_cluster_this_node(unsigned int *node); |
245 | |
246 | struct ocfs2_lock_res; |
247 | int ocfs2_dlm_lock(struct ocfs2_cluster_connection *conn, |
248 | int mode, |
249 | union ocfs2_dlm_lksb *lksb, |
250 | u32 flags, |
251 | void *name, |
252 | unsigned int namelen, |
253 | struct ocfs2_lock_res *astarg); |
254 | int ocfs2_dlm_unlock(struct ocfs2_cluster_connection *conn, |
255 | union ocfs2_dlm_lksb *lksb, |
256 | u32 flags, |
257 | struct ocfs2_lock_res *astarg); |
258 | |
259 | int ocfs2_dlm_lock_status(union ocfs2_dlm_lksb *lksb); |
260 | int ocfs2_dlm_lvb_valid(union ocfs2_dlm_lksb *lksb); |
261 | void *ocfs2_dlm_lvb(union ocfs2_dlm_lksb *lksb); |
262 | void ocfs2_dlm_dump_lksb(union ocfs2_dlm_lksb *lksb); |
263 | |
264 | int ocfs2_stack_supports_plocks(void); |
265 | int ocfs2_plock(struct ocfs2_cluster_connection *conn, u64 ino, |
266 | struct file *file, int cmd, struct file_lock *fl); |
267 | |
268 | void ocfs2_stack_glue_set_locking_protocol(struct ocfs2_locking_protocol *proto); |
269 | |
270 | |
271 | /* Used by stack plugins */ |
272 | int ocfs2_stack_glue_register(struct ocfs2_stack_plugin *plugin); |
273 | void ocfs2_stack_glue_unregister(struct ocfs2_stack_plugin *plugin); |
274 | |
275 | #endif /* STACKGLUE_H */ |
276 |
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