1 /* SPDX-License-Identifier: GPL-2.0-only */ 2 /* -*- mode: c; c-basic-offset: 8; -*- 3 * vim: noexpandtab sw=8 ts=8 sts=0: 4 * 5 * stackglue.h 6 * 7 * Glue to the underlying cluster stack. 8 * 9 * Copyright (C) 2007 Oracle. All rights reserved. 10 */ 11 12 13 #ifndef STACKGLUE_H 14 #define STACKGLUE_H 15 16 #include <linux/types.h> 17 #include <linux/list.h> 18 #include <linux/dlmconstants.h> 19 20 #include "dlm/dlmapi.h" 21 #include <linux/dlm.h> 22 23 /* Needed for plock-related prototypes */ 24 struct file; 25 struct file_lock; 26 27 /* 28 * dlmconstants.h does not have a LOCAL flag. We hope to remove it 29 * some day, but right now we need it. Let's fake it. This value is larger 30 * than any flag in dlmconstants.h. 31 */ 32 #define DLM_LKF_LOCAL 0x00100000 33 34 /* 35 * This shadows DLM_LOCKSPACE_LEN in fs/dlm/dlm_internal.h. That probably 36 * wants to be in a public header. 37 */ 38 #define GROUP_NAME_MAX 64 39 40 /* This shadows OCFS2_CLUSTER_NAME_LEN */ 41 #define CLUSTER_NAME_MAX 16 42 43 44 /* 45 * ocfs2_protocol_version changes when ocfs2 does something different in 46 * its inter-node behavior. See dlmglue.c for more information. 47 */ 48 struct ocfs2_protocol_version { 49 u8 pv_major; 50 u8 pv_minor; 51 }; 52 53 /* 54 * The dlm_lockstatus struct includes lvb space, but the dlm_lksb struct only 55 * has a pointer to separately allocated lvb space. This struct exists only to 56 * include in the lksb union to make space for a combined dlm_lksb and lvb. 57 */ 58 struct fsdlm_lksb_plus_lvb { 59 struct dlm_lksb lksb; 60 char lvb[DLM_LVB_LEN]; 61 }; 62 63 /* 64 * A union of all lock status structures. We define it here so that the 65 * size of the union is known. Lock status structures are embedded in 66 * ocfs2 inodes. 67 */ 68 struct ocfs2_cluster_connection; 69 struct ocfs2_dlm_lksb { 70 union { 71 struct dlm_lockstatus lksb_o2dlm; 72 struct dlm_lksb lksb_fsdlm; 73 struct fsdlm_lksb_plus_lvb padding; 74 }; 75 struct ocfs2_cluster_connection *lksb_conn; 76 }; 77 78 /* 79 * The ocfs2_locking_protocol defines the handlers called on ocfs2's behalf. 80 */ 81 struct ocfs2_locking_protocol { 82 struct ocfs2_protocol_version lp_max_version; 83 void (*lp_lock_ast)(struct ocfs2_dlm_lksb *lksb); 84 void (*lp_blocking_ast)(struct ocfs2_dlm_lksb *lksb, int level); 85 void (*lp_unlock_ast)(struct ocfs2_dlm_lksb *lksb, int error); 86 }; 87 88 89 /* 90 * A cluster connection. Mostly opaque to ocfs2, the connection holds 91 * state for the underlying stack. ocfs2 does use cc_version to determine 92 * locking compatibility. 93 */ 94 struct ocfs2_cluster_connection { 95 char cc_name[GROUP_NAME_MAX + 1]; 96 int cc_namelen; 97 char cc_cluster_name[CLUSTER_NAME_MAX + 1]; 98 int cc_cluster_name_len; 99 struct ocfs2_protocol_version cc_version; 100 struct ocfs2_locking_protocol *cc_proto; 101 void (*cc_recovery_handler)(int node_num, void *recovery_data); 102 void *cc_recovery_data; 103 void *cc_lockspace; 104 void *cc_private; 105 }; 106 107 /* 108 * Each cluster stack implements the stack operations structure. Not used 109 * in the ocfs2 code, the stackglue code translates generic cluster calls 110 * into stack operations. 111 */ 112 struct ocfs2_stack_operations { 113 /* 114 * The fs code calls ocfs2_cluster_connect() to attach a new 115 * filesystem to the cluster stack. The ->connect() op is passed 116 * an ocfs2_cluster_connection with the name and recovery field 117 * filled in. 118 * 119 * The stack must set up any notification mechanisms and create 120 * the filesystem lockspace in the DLM. The lockspace should be 121 * stored on cc_lockspace. Any other information can be stored on 122 * cc_private. 123 * 124 * ->connect() must not return until it is guaranteed that 125 * 126 * - Node down notifications for the filesystem will be received 127 * and passed to conn->cc_recovery_handler(). 128 * - Locking requests for the filesystem will be processed. 129 */ 130 int (*connect)(struct ocfs2_cluster_connection *conn); 131 132 /* 133 * The fs code calls ocfs2_cluster_disconnect() when a filesystem 134 * no longer needs cluster services. All DLM locks have been 135 * dropped, and recovery notification is being ignored by the 136 * fs code. The stack must disengage from the DLM and discontinue 137 * recovery notification. 138 * 139 * Once ->disconnect() has returned, the connection structure will 140 * be freed. Thus, a stack must not return from ->disconnect() 141 * until it will no longer reference the conn pointer. 142 * 143 * Once this call returns, the stack glue will be dropping this 144 * connection's reference on the module. 145 */ 146 int (*disconnect)(struct ocfs2_cluster_connection *conn); 147 148 /* 149 * ->this_node() returns the cluster's unique identifier for the 150 * local node. 151 */ 152 int (*this_node)(struct ocfs2_cluster_connection *conn, 153 unsigned int *node); 154 155 /* 156 * Call the underlying dlm lock function. The ->dlm_lock() 157 * callback should convert the flags and mode as appropriate. 158 * 159 * ast and bast functions are not part of the call because the 160 * stack will likely want to wrap ast and bast calls before passing 161 * them to stack->sp_proto. There is no astarg. The lksb will 162 * be passed back to the ast and bast functions. The caller can 163 * use this to find their object. 164 */ 165 int (*dlm_lock)(struct ocfs2_cluster_connection *conn, 166 int mode, 167 struct ocfs2_dlm_lksb *lksb, 168 u32 flags, 169 void *name, 170 unsigned int namelen); 171 172 /* 173 * Call the underlying dlm unlock function. The ->dlm_unlock() 174 * function should convert the flags as appropriate. 175 * 176 * The unlock ast is not passed, as the stack will want to wrap 177 * it before calling stack->sp_proto->lp_unlock_ast(). There is 178 * no astarg. The lksb will be passed back to the unlock ast 179 * function. The caller can use this to find their object. 180 */ 181 int (*dlm_unlock)(struct ocfs2_cluster_connection *conn, 182 struct ocfs2_dlm_lksb *lksb, 183 u32 flags); 184 185 /* 186 * Return the status of the current lock status block. The fs 187 * code should never dereference the union. The ->lock_status() 188 * callback pulls out the stack-specific lksb, converts the status 189 * to a proper errno, and returns it. 190 */ 191 int (*lock_status)(struct ocfs2_dlm_lksb *lksb); 192 193 /* 194 * Return non-zero if the LVB is valid. 195 */ 196 int (*lvb_valid)(struct ocfs2_dlm_lksb *lksb); 197 198 /* 199 * Pull the lvb pointer off of the stack-specific lksb. 200 */ 201 void *(*lock_lvb)(struct ocfs2_dlm_lksb *lksb); 202 203 /* 204 * Cluster-aware posix locks 205 * 206 * This is NULL for stacks which do not support posix locks. 207 */ 208 int (*plock)(struct ocfs2_cluster_connection *conn, 209 u64 ino, 210 struct file *file, 211 int cmd, 212 struct file_lock *fl); 213 214 /* 215 * This is an optoinal debugging hook. If provided, the 216 * stack can dump debugging information about this lock. 217 */ 218 void (*dump_lksb)(struct ocfs2_dlm_lksb *lksb); 219 }; 220 221 /* 222 * Each stack plugin must describe itself by registering a 223 * ocfs2_stack_plugin structure. This is only seen by stackglue and the 224 * stack driver. 225 */ 226 struct ocfs2_stack_plugin { 227 char *sp_name; 228 struct ocfs2_stack_operations *sp_ops; 229 struct module *sp_owner; 230 231 /* These are managed by the stackglue code. */ 232 struct list_head sp_list; 233 unsigned int sp_count; 234 struct ocfs2_protocol_version sp_max_proto; 235 }; 236 237 238 /* Used by the filesystem */ 239 int ocfs2_cluster_connect(const char *stack_name, 240 const char *cluster_name, 241 int cluster_name_len, 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(struct ocfs2_cluster_connection *conn, 264 unsigned int *node); 265 266 struct ocfs2_lock_res; 267 int ocfs2_dlm_lock(struct ocfs2_cluster_connection *conn, 268 int mode, 269 struct ocfs2_dlm_lksb *lksb, 270 u32 flags, 271 void *name, 272 unsigned int namelen); 273 int ocfs2_dlm_unlock(struct ocfs2_cluster_connection *conn, 274 struct ocfs2_dlm_lksb *lksb, 275 u32 flags); 276 277 int ocfs2_dlm_lock_status(struct ocfs2_dlm_lksb *lksb); 278 int ocfs2_dlm_lvb_valid(struct ocfs2_dlm_lksb *lksb); 279 void *ocfs2_dlm_lvb(struct ocfs2_dlm_lksb *lksb); 280 void ocfs2_dlm_dump_lksb(struct ocfs2_dlm_lksb *lksb); 281 282 int ocfs2_stack_supports_plocks(void); 283 int ocfs2_plock(struct ocfs2_cluster_connection *conn, u64 ino, 284 struct file *file, int cmd, struct file_lock *fl); 285 286 void ocfs2_stack_glue_set_max_proto_version(struct ocfs2_protocol_version *max_proto); 287 288 289 /* Used by stack plugins */ 290 int ocfs2_stack_glue_register(struct ocfs2_stack_plugin *plugin); 291 void ocfs2_stack_glue_unregister(struct ocfs2_stack_plugin *plugin); 292 293 extern struct kset *ocfs2_kset; 294 295 #endif /* STACKGLUE_H */ 296