1 /******************************************************************************
2 *******************************************************************************
4 ** Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
5 ** Copyright (C) 2004-2005 Red Hat, Inc. All rights reserved.
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.
11 *******************************************************************************
12 ******************************************************************************/
18 * Interface to Distributed Lock Manager (DLM)
19 * routines and structures to use DLM lockspaces
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 */
35 * Maximum size in bytes of a dlm_lock name
38 #define DLM_RESNAME_MAXLEN 64
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.
52 * Used to cancel a pending lock request or conversion. A converting lock is
53 * returned to its previously granted mode.
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.
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.
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.
75 * Invalidate the lock value block.
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.
85 * Only relevant to locks originating in userspace. A persistent lock will not
86 * be removed if the process holding the lock exits.
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.
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.
106 * Add a lock to the head of the convert or wait queue rather than the tail.
110 * Disregard the standard grant order rules and grant a lock as soon as it
111 * is compatible with other granted locks.
115 * not yet implemented
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.
125 * The same as ALTPR, but the alternate mode is CW.
127 * DLM_LKF_FORCEUNLOCK
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.
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
154 * Some return codes that are not in errno.h
157 #define DLM_ECANCEL 0x10001
158 #define DLM_EUNLOCK 0x10002
160 typedef void dlm_lockspace_t
;
165 * Use this structure to specify the contents of the lock value block. For a
166 * conversion request, this structure is used to specify the lock ID of the
167 * lock. DLM writes the status of the lock request and the lock ID assigned
168 * to the request in the lock status block.
170 * sb_lkid: the returned lock ID. It is set on new (non-conversion) requests.
171 * It is available when dlm_lock returns.
173 * sb_lvbptr: saves or returns the contents of the lock's LVB according to rules
174 * shown for the DLM_LKF_VALBLK flag.
176 * sb_flags: DLM_SBF_DEMOTED is returned if in the process of promoting a lock,
177 * it was first demoted to NL to avoid conversion deadlock.
178 * DLM_SBF_VALNOTVALID is returned if the resource's LVB is marked invalid.
180 * sb_status: the returned status of the lock request set prior to AST
181 * execution. Possible return values:
183 * 0 if lock request was successful
184 * -EAGAIN if request would block and is flagged DLM_LKF_NOQUEUE
185 * -ENOMEM if there is no memory to process request
186 * -EINVAL if there are invalid parameters
187 * -DLM_EUNLOCK if unlock request was successful
188 * -DLM_ECANCEL if a cancel completed successfully
191 #define DLM_SBF_DEMOTED 0x01
192 #define DLM_SBF_VALNOTVALID 0x02
193 #define DLM_SBF_ALTMODE 0x04
205 #define DLM_LSFL_NODIR 0x00000001
210 * Starts a lockspace with the given name. If the named lockspace exists in
211 * the cluster, the calling node joins it.
214 int dlm_new_lockspace(char *name
, int namelen
, dlm_lockspace_t
**lockspace
,
215 uint32_t flags
, int lvblen
);
218 * dlm_release_lockspace
223 int dlm_release_lockspace(dlm_lockspace_t
*lockspace
, int force
);
228 * Make an asyncronous request to acquire or convert a lock on a named
231 * lockspace: context for the request
232 * mode: the requested mode of the lock (DLM_LOCK_)
233 * lksb: lock status block for input and async return values
234 * flags: input flags (DLM_LKF_)
235 * name: name of the resource to lock, can be binary
236 * namelen: the length in bytes of the resource name (MAX_RESNAME_LEN)
237 * parent: the lock ID of a parent lock or 0 if none
238 * lockast: function DLM executes when it completes processing the request
239 * astarg: argument passed to lockast and bast functions
240 * bast: function DLM executes when this lock later blocks another request
243 * 0 if request is successfully queued for processing
244 * -EINVAL if any input parameters are invalid
245 * -EAGAIN if request would block and is flagged DLM_LKF_NOQUEUE
246 * -ENOMEM if there is no memory to process request
247 * -ENOTCONN if there is a communication error
249 * If the call to dlm_lock returns an error then the operation has failed and
250 * the AST routine will not be called. If dlm_lock returns 0 it is still
251 * possible that the lock operation will fail. The AST routine will be called
252 * when the locking is complete and the status is returned in the lksb.
254 * If the AST routines or parameter are passed to a conversion operation then
255 * they will overwrite those values that were passed to a previous dlm_lock
258 * AST routines should not block (at least not for long), but may make
259 * any locking calls they please.
262 int dlm_lock(dlm_lockspace_t
*lockspace
,
264 struct dlm_lksb
*lksb
,
267 unsigned int namelen
,
268 uint32_t parent_lkid
,
269 void (*lockast
) (void *astarg
),
271 void (*bast
) (void *astarg
, int mode
));
276 * Asynchronously release a lock on a resource. The AST routine is called
277 * when the resource is successfully unlocked.
279 * lockspace: context for the request
280 * lkid: the lock ID as returned in the lksb
281 * flags: input flags (DLM_LKF_)
282 * lksb: if NULL the lksb parameter passed to last lock request is used
283 * astarg: the arg used with the completion ast for the unlock
286 * 0 if request is successfully queued for processing
287 * -EINVAL if any input parameters are invalid
288 * -ENOTEMPTY if the lock still has sublocks
289 * -EBUSY if the lock is waiting for a remote lock operation
290 * -ENOTCONN if there is a communication error
293 int dlm_unlock(dlm_lockspace_t
*lockspace
,
296 struct dlm_lksb
*lksb
,
299 #endif /* __KERNEL__ */
301 #endif /* __DLM_DOT_H__ */
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