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 dlm_lockstatus struct includes lvb space, but the dlm_lksb struct only 60 * has a pointer to separately allocated lvb space. This struct exists only to 61 * include in the lksb union to make space for a combined dlm_lksb and lvb. 62 */ 63 struct fsdlm_lksb_plus_lvb { 64 struct dlm_lksb lksb; 65 char lvb[DLM_LVB_LEN]; 66 }; 67 68 /* 69 * A union of all lock status structures. We define it here so that the 70 * size of the union is known. Lock status structures are embedded in 71 * ocfs2 inodes. 72 */ 73 struct ocfs2_cluster_connection; 74 struct ocfs2_dlm_lksb { 75 union { 76 struct dlm_lockstatus lksb_o2dlm; 77 struct dlm_lksb lksb_fsdlm; 78 struct fsdlm_lksb_plus_lvb padding; 79 }; 80 struct ocfs2_cluster_connection *lksb_conn; 81 }; 82 83 /* 84 * The ocfs2_locking_protocol defines the handlers called on ocfs2's behalf. 85 */ 86 struct ocfs2_locking_protocol { 87 struct ocfs2_protocol_version lp_max_version; 88 void (*lp_lock_ast)(struct ocfs2_dlm_lksb *lksb); 89 void (*lp_blocking_ast)(struct ocfs2_dlm_lksb *lksb, int level); 90 void (*lp_unlock_ast)(struct ocfs2_dlm_lksb *lksb, int error); 91 }; 92 93 94 /* 95 * A cluster connection. Mostly opaque to ocfs2, the connection holds 96 * state for the underlying stack. ocfs2 does use cc_version to determine 97 * locking compatibility. 98 */ 99 struct ocfs2_cluster_connection { 100 char cc_name[GROUP_NAME_MAX]; 101 int cc_namelen; 102 struct ocfs2_protocol_version cc_version; 103 struct ocfs2_locking_protocol *cc_proto; 104 void (*cc_recovery_handler)(int node_num, void *recovery_data); 105 void *cc_recovery_data; 106 void *cc_lockspace; 107 void *cc_private; 108 }; 109 110 /* 111 * Each cluster stack implements the stack operations structure. Not used 112 * in the ocfs2 code, the stackglue code translates generic cluster calls 113 * into stack operations. 114 */ 115 struct ocfs2_stack_operations { 116 /* 117 * The fs code calls ocfs2_cluster_connect() to attach a new 118 * filesystem to the cluster stack. The ->connect() op is passed 119 * an ocfs2_cluster_connection with the name and recovery field 120 * filled in. 121 * 122 * The stack must set up any notification mechanisms and create 123 * the filesystem lockspace in the DLM. The lockspace should be 124 * stored on cc_lockspace. Any other information can be stored on 125 * cc_private. 126 * 127 * ->connect() must not return until it is guaranteed that 128 * 129 * - Node down notifications for the filesystem will be received 130 * and passed to conn->cc_recovery_handler(). 131 * - Locking requests for the filesystem will be processed. 132 */ 133 int (*connect)(struct ocfs2_cluster_connection *conn); 134 135 /* 136 * The fs code calls ocfs2_cluster_disconnect() when a filesystem 137 * no longer needs cluster services. All DLM locks have been 138 * dropped, and recovery notification is being ignored by the 139 * fs code. The stack must disengage from the DLM and discontinue 140 * recovery notification. 141 * 142 * Once ->disconnect() has returned, the connection structure will 143 * be freed. Thus, a stack must not return from ->disconnect() 144 * until it will no longer reference the conn pointer. 145 * 146 * Once this call returns, the stack glue will be dropping this 147 * connection's reference on the module. 148 */ 149 int (*disconnect)(struct ocfs2_cluster_connection *conn); 150 151 /* 152 * ->this_node() returns the cluster's unique identifier for the 153 * local node. 154 */ 155 int (*this_node)(unsigned int *node); 156 157 /* 158 * Call the underlying dlm lock function. The ->dlm_lock() 159 * callback should convert the flags and mode as appropriate. 160 * 161 * ast and bast functions are not part of the call because the 162 * stack will likely want to wrap ast and bast calls before passing 163 * them to stack->sp_proto. There is no astarg. The lksb will 164 * be passed back to the ast and bast functions. The caller can 165 * use this to find their object. 166 */ 167 int (*dlm_lock)(struct ocfs2_cluster_connection *conn, 168 int mode, 169 struct ocfs2_dlm_lksb *lksb, 170 u32 flags, 171 void *name, 172 unsigned int namelen); 173 174 /* 175 * Call the underlying dlm unlock function. The ->dlm_unlock() 176 * function should convert the flags as appropriate. 177 * 178 * The unlock ast is not passed, as the stack will want to wrap 179 * it before calling stack->sp_proto->lp_unlock_ast(). There is 180 * no astarg. The lksb will be passed back to the unlock ast 181 * function. The caller can use this to find their object. 182 */ 183 int (*dlm_unlock)(struct ocfs2_cluster_connection *conn, 184 struct ocfs2_dlm_lksb *lksb, 185 u32 flags); 186 187 /* 188 * Return the status of the current lock status block. The fs 189 * code should never dereference the union. The ->lock_status() 190 * callback pulls out the stack-specific lksb, converts the status 191 * to a proper errno, and returns it. 192 */ 193 int (*lock_status)(struct ocfs2_dlm_lksb *lksb); 194 195 /* 196 * Return non-zero if the LVB is valid. 197 */ 198 int (*lvb_valid)(struct ocfs2_dlm_lksb *lksb); 199 200 /* 201 * Pull the lvb pointer off of the stack-specific lksb. 202 */ 203 void *(*lock_lvb)(struct ocfs2_dlm_lksb *lksb); 204 205 /* 206 * Cluster-aware posix locks 207 * 208 * This is NULL for stacks which do not support posix locks. 209 */ 210 int (*plock)(struct ocfs2_cluster_connection *conn, 211 u64 ino, 212 struct file *file, 213 int cmd, 214 struct file_lock *fl); 215 216 /* 217 * This is an optoinal debugging hook. If provided, the 218 * stack can dump debugging information about this lock. 219 */ 220 void (*dump_lksb)(struct ocfs2_dlm_lksb *lksb); 221 }; 222 223 /* 224 * Each stack plugin must describe itself by registering a 225 * ocfs2_stack_plugin structure. This is only seen by stackglue and the 226 * stack driver. 227 */ 228 struct ocfs2_stack_plugin { 229 char *sp_name; 230 struct ocfs2_stack_operations *sp_ops; 231 struct module *sp_owner; 232 233 /* These are managed by the stackglue code. */ 234 struct list_head sp_list; 235 unsigned int sp_count; 236 struct ocfs2_protocol_version sp_max_proto; 237 }; 238 239 240 /* Used by the filesystem */ 241 int ocfs2_cluster_connect(const char *stack_name, 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(unsigned int *node); 264 265 struct ocfs2_lock_res; 266 int ocfs2_dlm_lock(struct ocfs2_cluster_connection *conn, 267 int mode, 268 struct ocfs2_dlm_lksb *lksb, 269 u32 flags, 270 void *name, 271 unsigned int namelen); 272 int ocfs2_dlm_unlock(struct ocfs2_cluster_connection *conn, 273 struct ocfs2_dlm_lksb *lksb, 274 u32 flags); 275 276 int ocfs2_dlm_lock_status(struct ocfs2_dlm_lksb *lksb); 277 int ocfs2_dlm_lvb_valid(struct ocfs2_dlm_lksb *lksb); 278 void *ocfs2_dlm_lvb(struct ocfs2_dlm_lksb *lksb); 279 void ocfs2_dlm_dump_lksb(struct ocfs2_dlm_lksb *lksb); 280 281 int ocfs2_stack_supports_plocks(void); 282 int ocfs2_plock(struct ocfs2_cluster_connection *conn, u64 ino, 283 struct file *file, int cmd, struct file_lock *fl); 284 285 void ocfs2_stack_glue_set_max_proto_version(struct ocfs2_protocol_version *max_proto); 286 287 288 /* Used by stack plugins */ 289 int ocfs2_stack_glue_register(struct ocfs2_stack_plugin *plugin); 290 void ocfs2_stack_glue_unregister(struct ocfs2_stack_plugin *plugin); 291 292 #endif /* STACKGLUE_H */ 293