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 | 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 | |