Linux kernel mirror (for testing)
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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
160typedef void dlm_lockspace_t;
161
162/*
163 * Lock status block
164 *
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.
169 *
170 * sb_lkid: the returned lock ID. It is set on new (non-conversion) requests.
171 * It is available when dlm_lock returns.
172 *
173 * sb_lvbptr: saves or returns the contents of the lock's LVB according to rules
174 * shown for the DLM_LKF_VALBLK flag.
175 *
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.
179 *
180 * sb_status: the returned status of the lock request set prior to AST
181 * execution. Possible return values:
182 *
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
189 */
190
191#define DLM_SBF_DEMOTED 0x01
192#define DLM_SBF_VALNOTVALID 0x02
193#define DLM_SBF_ALTMODE 0x04
194
195struct dlm_lksb {
196 int sb_status;
197 uint32_t sb_lkid;
198 char sb_flags;
199 char * sb_lvbptr;
200};
201
202
203#ifdef __KERNEL__
204
205#define DLM_LSFL_NODIR 0x00000001
206
207/*
208 * dlm_new_lockspace
209 *
210 * Starts a lockspace with the given name. If the named lockspace exists in
211 * the cluster, the calling node joins it.
212 */
213
214int dlm_new_lockspace(char *name, int namelen, dlm_lockspace_t **lockspace,
215 uint32_t flags, int lvblen);
216
217/*
218 * dlm_release_lockspace
219 *
220 * Stop a lockspace.
221 */
222
223int dlm_release_lockspace(dlm_lockspace_t *lockspace, int force);
224
225/*
226 * dlm_lock
227 *
228 * Make an asyncronous request to acquire or convert a lock on a named
229 * resource.
230 *
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
241 *
242 * Returns:
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
248 *
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.
253 *
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
256 * call.
257 *
258 * AST routines should not block (at least not for long), but may make
259 * any locking calls they please.
260 */
261
262int dlm_lock(dlm_lockspace_t *lockspace,
263 int mode,
264 struct dlm_lksb *lksb,
265 uint32_t flags,
266 void *name,
267 unsigned int namelen,
268 uint32_t parent_lkid,
269 void (*lockast) (void *astarg),
270 void *astarg,
271 void (*bast) (void *astarg, int mode));
272
273/*
274 * dlm_unlock
275 *
276 * Asynchronously release a lock on a resource. The AST routine is called
277 * when the resource is successfully unlocked.
278 *
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
284 *
285 * Returns:
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
291 */
292
293int dlm_unlock(dlm_lockspace_t *lockspace,
294 uint32_t lkid,
295 uint32_t flags,
296 struct dlm_lksb *lksb,
297 void *astarg);
298
299#endif /* __KERNEL__ */
300
301#endif /* __DLM_DOT_H__ */
302