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 * Pull the lvb pointer off of the stack-specific lksb. 190 */ 191 void *(*lock_lvb)(union ocfs2_dlm_lksb *lksb); 192 193 /* 194 * Cluster-aware posix locks 195 * 196 * This is NULL for stacks which do not support posix locks. 197 */ 198 int (*plock)(struct ocfs2_cluster_connection *conn, 199 u64 ino, 200 struct file *file, 201 int cmd, 202 struct file_lock *fl); 203 204 /* 205 * This is an optoinal debugging hook. If provided, the 206 * stack can dump debugging information about this lock. 207 */ 208 void (*dump_lksb)(union ocfs2_dlm_lksb *lksb); 209 }; 210 211 /* 212 * Each stack plugin must describe itself by registering a 213 * ocfs2_stack_plugin structure. This is only seen by stackglue and the 214 * stack driver. 215 */ 216 struct ocfs2_stack_plugin { 217 char *sp_name; 218 struct ocfs2_stack_operations *sp_ops; 219 struct module *sp_owner; 220 221 /* These are managed by the stackglue code. */ 222 struct list_head sp_list; 223 unsigned int sp_count; 224 struct ocfs2_locking_protocol *sp_proto; 225 }; 226 227 228 /* Used by the filesystem */ 229 int ocfs2_cluster_connect(const char *stack_name, 230 const char *group, 231 int grouplen, 232 void (*recovery_handler)(int node_num, 233 void *recovery_data), 234 void *recovery_data, 235 struct ocfs2_cluster_connection **conn); 236 int ocfs2_cluster_disconnect(struct ocfs2_cluster_connection *conn, 237 int hangup_pending); 238 void ocfs2_cluster_hangup(const char *group, int grouplen); 239 int ocfs2_cluster_this_node(unsigned int *node); 240 241 struct ocfs2_lock_res; 242 int ocfs2_dlm_lock(struct ocfs2_cluster_connection *conn, 243 int mode, 244 union ocfs2_dlm_lksb *lksb, 245 u32 flags, 246 void *name, 247 unsigned int namelen, 248 struct ocfs2_lock_res *astarg); 249 int ocfs2_dlm_unlock(struct ocfs2_cluster_connection *conn, 250 union ocfs2_dlm_lksb *lksb, 251 u32 flags, 252 struct ocfs2_lock_res *astarg); 253 254 int ocfs2_dlm_lock_status(union ocfs2_dlm_lksb *lksb); 255 void *ocfs2_dlm_lvb(union ocfs2_dlm_lksb *lksb); 256 void ocfs2_dlm_dump_lksb(union ocfs2_dlm_lksb *lksb); 257 258 int ocfs2_stack_supports_plocks(void); 259 int ocfs2_plock(struct ocfs2_cluster_connection *conn, u64 ino, 260 struct file *file, int cmd, struct file_lock *fl); 261 262 void ocfs2_stack_glue_set_locking_protocol(struct ocfs2_locking_protocol *proto); 263 264 265 /* Used by stack plugins */ 266 int ocfs2_stack_glue_register(struct ocfs2_stack_plugin *plugin); 267 void ocfs2_stack_glue_unregister(struct ocfs2_stack_plugin *plugin); 268 269 #endif /* STACKGLUE_H */ 270