1 /****************************************************************************** 2 ******************************************************************************* 3 ** 4 ** Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved. 5 ** Copyright (C) 2004-2005 Red Hat, Inc. All rights reserved. 6 ** 7 ** This copyrighted material is made available to anyone wishing to use, 8 ** modify, copy, or redistribute it subject to the terms and conditions 9 ** of the GNU General Public License v.2. 10 ** 11 ******************************************************************************* 12 ******************************************************************************/ 13 14 #ifndef __DLM_DOT_H__ 15 #define __DLM_DOT_H__ 16 17 /* 18 * Interface to Distributed Lock Manager (DLM) 19 * routines and structures to use DLM lockspaces 20 */ 21 22 /* 23 * Lock Modes 24 */ 25 26 #define DLM_LOCK_IV -1 /* invalid */ 27 #define DLM_LOCK_NL 0 /* null */ 28 #define DLM_LOCK_CR 1 /* concurrent read */ 29 #define DLM_LOCK_CW 2 /* concurrent write */ 30 #define DLM_LOCK_PR 3 /* protected read */ 31 #define DLM_LOCK_PW 4 /* protected write */ 32 #define DLM_LOCK_EX 5 /* exclusive */ 33 34 /* 35 * Maximum size in bytes of a dlm_lock name 36 */ 37 38 #define DLM_RESNAME_MAXLEN 64 39 40 /* 41 * Flags to dlm_lock 42 * 43 * DLM_LKF_NOQUEUE 44 * 45 * Do not queue the lock request on the wait queue if it cannot be granted 46 * immediately. If the lock cannot be granted because of this flag, DLM will 47 * either return -EAGAIN from the dlm_lock call or will return 0 from 48 * dlm_lock and -EAGAIN in the lock status block when the AST is executed. 49 * 50 * DLM_LKF_CANCEL 51 * 52 * Used to cancel a pending lock request or conversion. A converting lock is 53 * returned to its previously granted mode. 54 * 55 * DLM_LKF_CONVERT 56 * 57 * Indicates a lock conversion request. For conversions the name and namelen 58 * are ignored and the lock ID in the LKSB is used to identify the lock. 59 * 60 * DLM_LKF_VALBLK 61 * 62 * Requests DLM to return the current contents of the lock value block in the 63 * lock status block. When this flag is set in a lock conversion from PW or EX 64 * modes, DLM assigns the value specified in the lock status block to the lock 65 * value block of the lock resource. The LVB is a DLM_LVB_LEN size array 66 * containing application-specific information. 67 * 68 * DLM_LKF_QUECVT 69 * 70 * Force a conversion request to be queued, even if it is compatible with 71 * the granted modes of other locks on the same resource. 72 * 73 * DLM_LKF_IVVALBLK 74 * 75 * Invalidate the lock value block. 76 * 77 * DLM_LKF_CONVDEADLK 78 * 79 * Allows the dlm to resolve conversion deadlocks internally by demoting the 80 * granted mode of a converting lock to NL. The DLM_SBF_DEMOTED flag is 81 * returned for a conversion that's been effected by this. 82 * 83 * DLM_LKF_PERSISTENT 84 * 85 * Only relevant to locks originating in userspace. A persistent lock will not 86 * be removed if the process holding the lock exits. 87 * 88 * DLM_LKF_NODLKWT 89 * DLM_LKF_NODLCKBLK 90 * 91 * net yet implemented 92 * 93 * DLM_LKF_EXPEDITE 94 * 95 * Used only with new requests for NL mode locks. Tells the lock manager 96 * to grant the lock, ignoring other locks in convert and wait queues. 97 * 98 * DLM_LKF_NOQUEUEBAST 99 * 100 * Send blocking AST's before returning -EAGAIN to the caller. It is only 101 * used along with the NOQUEUE flag. Blocking AST's are not sent for failed 102 * NOQUEUE requests otherwise. 103 * 104 * DLM_LKF_HEADQUE 105 * 106 * Add a lock to the head of the convert or wait queue rather than the tail. 107 * 108 * DLM_LKF_NOORDER 109 * 110 * Disregard the standard grant order rules and grant a lock as soon as it 111 * is compatible with other granted locks. 112 * 113 * DLM_LKF_ORPHAN 114 * 115 * not yet implemented 116 * 117 * DLM_LKF_ALTPR 118 * 119 * If the requested mode cannot be granted immediately, try to grant the lock 120 * in PR mode instead. If this alternate mode is granted instead of the 121 * requested mode, DLM_SBF_ALTMODE is returned in the lksb. 122 * 123 * DLM_LKF_ALTCW 124 * 125 * The same as ALTPR, but the alternate mode is CW. 126 * 127 * DLM_LKF_FORCEUNLOCK 128 * 129 * Unlock the lock even if it is converting or waiting or has sublocks. 130 * Only really for use by the userland device.c code. 131 * 132 */ 133 134 #define DLM_LKF_NOQUEUE 0x00000001 135 #define DLM_LKF_CANCEL 0x00000002 136 #define DLM_LKF_CONVERT 0x00000004 137 #define DLM_LKF_VALBLK 0x00000008 138 #define DLM_LKF_QUECVT 0x00000010 139 #define DLM_LKF_IVVALBLK 0x00000020 140 #define DLM_LKF_CONVDEADLK 0x00000040 141 #define DLM_LKF_PERSISTENT 0x00000080 142 #define DLM_LKF_NODLCKWT 0x00000100 143 #define DLM_LKF_NODLCKBLK 0x00000200 144 #define DLM_LKF_EXPEDITE 0x00000400 145 #define DLM_LKF_NOQUEUEBAST 0x00000800 146 #define DLM_LKF_HEADQUE 0x00001000 147 #define DLM_LKF_NOORDER 0x00002000 148 #define DLM_LKF_ORPHAN 0x00004000 149 #define DLM_LKF_ALTPR 0x00008000 150 #define DLM_LKF_ALTCW 0x00010000 151 #define DLM_LKF_FORCEUNLOCK 0x00020000 152 153 /* 154 * Some return codes that are not in errno.h 155 */ 156 157 #define DLM_ECANCEL 0x10001 158 #define DLM_EUNLOCK 0x10002 159 160 typedef void dlm_lockspace_t; 161 162 /* 163 * Lock range structure 164 */ 165 166 struct dlm_range { 167 uint64_t ra_start; 168 uint64_t ra_end; 169 }; 170 171 /* 172 * Lock status block 173 * 174 * Use this structure to specify the contents of the lock value block. For a 175 * conversion request, this structure is used to specify the lock ID of the 176 * lock. DLM writes the status of the lock request and the lock ID assigned 177 * to the request in the lock status block. 178 * 179 * sb_lkid: the returned lock ID. It is set on new (non-conversion) requests. 180 * It is available when dlm_lock returns. 181 * 182 * sb_lvbptr: saves or returns the contents of the lock's LVB according to rules 183 * shown for the DLM_LKF_VALBLK flag. 184 * 185 * sb_flags: DLM_SBF_DEMOTED is returned if in the process of promoting a lock, 186 * it was first demoted to NL to avoid conversion deadlock. 187 * DLM_SBF_VALNOTVALID is returned if the resource's LVB is marked invalid. 188 * 189 * sb_status: the returned status of the lock request set prior to AST 190 * execution. Possible return values: 191 * 192 * 0 if lock request was successful 193 * -EAGAIN if request would block and is flagged DLM_LKF_NOQUEUE 194 * -ENOMEM if there is no memory to process request 195 * -EINVAL if there are invalid parameters 196 * -DLM_EUNLOCK if unlock request was successful 197 * -DLM_ECANCEL if a cancel completed successfully 198 */ 199 200 #define DLM_SBF_DEMOTED 0x01 201 #define DLM_SBF_VALNOTVALID 0x02 202 #define DLM_SBF_ALTMODE 0x04 203 204 struct dlm_lksb { 205 int sb_status; 206 uint32_t sb_lkid; 207 char sb_flags; 208 char * sb_lvbptr; 209 }; 210 211 212 #ifdef __KERNEL__ 213 214 #define DLM_LSFL_NODIR 0x00000001 215 216 /* 217 * dlm_new_lockspace 218 * 219 * Starts a lockspace with the given name. If the named lockspace exists in 220 * the cluster, the calling node joins it. 221 */ 222 223 int dlm_new_lockspace(char *name, int namelen, dlm_lockspace_t **lockspace, 224 uint32_t flags, int lvblen); 225 226 /* 227 * dlm_release_lockspace 228 * 229 * Stop a lockspace. 230 */ 231 232 int dlm_release_lockspace(dlm_lockspace_t *lockspace, int force); 233 234 /* 235 * dlm_lock 236 * 237 * Make an asyncronous request to acquire or convert a lock on a named 238 * resource. 239 * 240 * lockspace: context for the request 241 * mode: the requested mode of the lock (DLM_LOCK_) 242 * lksb: lock status block for input and async return values 243 * flags: input flags (DLM_LKF_) 244 * name: name of the resource to lock, can be binary 245 * namelen: the length in bytes of the resource name (MAX_RESNAME_LEN) 246 * parent: the lock ID of a parent lock or 0 if none 247 * lockast: function DLM executes when it completes processing the request 248 * astarg: argument passed to lockast and bast functions 249 * bast: function DLM executes when this lock later blocks another request 250 * 251 * Returns: 252 * 0 if request is successfully queued for processing 253 * -EINVAL if any input parameters are invalid 254 * -EAGAIN if request would block and is flagged DLM_LKF_NOQUEUE 255 * -ENOMEM if there is no memory to process request 256 * -ENOTCONN if there is a communication error 257 * 258 * If the call to dlm_lock returns an error then the operation has failed and 259 * the AST routine will not be called. If dlm_lock returns 0 it is still 260 * possible that the lock operation will fail. The AST routine will be called 261 * when the locking is complete and the status is returned in the lksb. 262 * 263 * If the AST routines or parameter are passed to a conversion operation then 264 * they will overwrite those values that were passed to a previous dlm_lock 265 * call. 266 * 267 * AST routines should not block (at least not for long), but may make 268 * any locking calls they please. 269 */ 270 271 int dlm_lock(dlm_lockspace_t *lockspace, 272 int mode, 273 struct dlm_lksb *lksb, 274 uint32_t flags, 275 void *name, 276 unsigned int namelen, 277 uint32_t parent_lkid, 278 void (*lockast) (void *astarg), 279 void *astarg, 280 void (*bast) (void *astarg, int mode), 281 struct dlm_range *range); 282 283 /* 284 * dlm_unlock 285 * 286 * Asynchronously release a lock on a resource. The AST routine is called 287 * when the resource is successfully unlocked. 288 * 289 * lockspace: context for the request 290 * lkid: the lock ID as returned in the lksb 291 * flags: input flags (DLM_LKF_) 292 * lksb: if NULL the lksb parameter passed to last lock request is used 293 * astarg: the arg used with the completion ast for the unlock 294 * 295 * Returns: 296 * 0 if request is successfully queued for processing 297 * -EINVAL if any input parameters are invalid 298 * -ENOTEMPTY if the lock still has sublocks 299 * -EBUSY if the lock is waiting for a remote lock operation 300 * -ENOTCONN if there is a communication error 301 */ 302 303 int dlm_unlock(dlm_lockspace_t *lockspace, 304 uint32_t lkid, 305 uint32_t flags, 306 struct dlm_lksb *lksb, 307 void *astarg); 308 309 #endif /* __KERNEL__ */ 310 311 #endif /* __DLM_DOT_H__ */ 312 313