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1/******************************************************************************
2*******************************************************************************
3**
4** Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
5** Copyright (C) 2004-2007 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_NODLCKWT
89 *
90 * Do not cancel the lock if it gets into conversion deadlock.
91 * Exclude this lock from being monitored due to DLM_LSFL_TIMEWARN.
92 *
93 * DLM_LKF_NODLCKBLK
94 *
95 * net yet implemented
96 *
97 * DLM_LKF_EXPEDITE
98 *
99 * Used only with new requests for NL mode locks. Tells the lock manager
100 * to grant the lock, ignoring other locks in convert and wait queues.
101 *
102 * DLM_LKF_NOQUEUEBAST
103 *
104 * Send blocking AST's before returning -EAGAIN to the caller. It is only
105 * used along with the NOQUEUE flag. Blocking AST's are not sent for failed
106 * NOQUEUE requests otherwise.
107 *
108 * DLM_LKF_HEADQUE
109 *
110 * Add a lock to the head of the convert or wait queue rather than the tail.
111 *
112 * DLM_LKF_NOORDER
113 *
114 * Disregard the standard grant order rules and grant a lock as soon as it
115 * is compatible with other granted locks.
116 *
117 * DLM_LKF_ORPHAN
118 *
119 * not yet implemented
120 *
121 * DLM_LKF_ALTPR
122 *
123 * If the requested mode cannot be granted immediately, try to grant the lock
124 * in PR mode instead. If this alternate mode is granted instead of the
125 * requested mode, DLM_SBF_ALTMODE is returned in the lksb.
126 *
127 * DLM_LKF_ALTCW
128 *
129 * The same as ALTPR, but the alternate mode is CW.
130 *
131 * DLM_LKF_FORCEUNLOCK
132 *
133 * Unlock the lock even if it is converting or waiting or has sublocks.
134 * Only really for use by the userland device.c code.
135 *
136 */
137
138#define DLM_LKF_NOQUEUE 0x00000001
139#define DLM_LKF_CANCEL 0x00000002
140#define DLM_LKF_CONVERT 0x00000004
141#define DLM_LKF_VALBLK 0x00000008
142#define DLM_LKF_QUECVT 0x00000010
143#define DLM_LKF_IVVALBLK 0x00000020
144#define DLM_LKF_CONVDEADLK 0x00000040
145#define DLM_LKF_PERSISTENT 0x00000080
146#define DLM_LKF_NODLCKWT 0x00000100
147#define DLM_LKF_NODLCKBLK 0x00000200
148#define DLM_LKF_EXPEDITE 0x00000400
149#define DLM_LKF_NOQUEUEBAST 0x00000800
150#define DLM_LKF_HEADQUE 0x00001000
151#define DLM_LKF_NOORDER 0x00002000
152#define DLM_LKF_ORPHAN 0x00004000
153#define DLM_LKF_ALTPR 0x00008000
154#define DLM_LKF_ALTCW 0x00010000
155#define DLM_LKF_FORCEUNLOCK 0x00020000
156#define DLM_LKF_TIMEOUT 0x00040000
157
158/*
159 * Some return codes that are not in errno.h
160 */
161
162#define DLM_ECANCEL 0x10001
163#define DLM_EUNLOCK 0x10002
164
165typedef void dlm_lockspace_t;
166
167/*
168 * Lock status block
169 *
170 * Use this structure to specify the contents of the lock value block. For a
171 * conversion request, this structure is used to specify the lock ID of the
172 * lock. DLM writes the status of the lock request and the lock ID assigned
173 * to the request in the lock status block.
174 *
175 * sb_lkid: the returned lock ID. It is set on new (non-conversion) requests.
176 * It is available when dlm_lock returns.
177 *
178 * sb_lvbptr: saves or returns the contents of the lock's LVB according to rules
179 * shown for the DLM_LKF_VALBLK flag.
180 *
181 * sb_flags: DLM_SBF_DEMOTED is returned if in the process of promoting a lock,
182 * it was first demoted to NL to avoid conversion deadlock.
183 * DLM_SBF_VALNOTVALID is returned if the resource's LVB is marked invalid.
184 *
185 * sb_status: the returned status of the lock request set prior to AST
186 * execution. Possible return values:
187 *
188 * 0 if lock request was successful
189 * -EAGAIN if request would block and is flagged DLM_LKF_NOQUEUE
190 * -ENOMEM if there is no memory to process request
191 * -EINVAL if there are invalid parameters
192 * -DLM_EUNLOCK if unlock request was successful
193 * -DLM_ECANCEL if a cancel completed successfully
194 */
195
196#define DLM_SBF_DEMOTED 0x01
197#define DLM_SBF_VALNOTVALID 0x02
198#define DLM_SBF_ALTMODE 0x04
199
200struct dlm_lksb {
201 int sb_status;
202 uint32_t sb_lkid;
203 char sb_flags;
204 char * sb_lvbptr;
205};
206
207#define DLM_LSFL_NODIR 0x00000001
208#define DLM_LSFL_TIMEWARN 0x00000002
209#define DLM_LSFL_FS 0x00000004
210
211#ifdef __KERNEL__
212
213/*
214 * dlm_new_lockspace
215 *
216 * Starts a lockspace with the given name. If the named lockspace exists in
217 * the cluster, the calling node joins it.
218 */
219
220int dlm_new_lockspace(char *name, int namelen, dlm_lockspace_t **lockspace,
221 uint32_t flags, int lvblen);
222
223/*
224 * dlm_release_lockspace
225 *
226 * Stop a lockspace.
227 */
228
229int dlm_release_lockspace(dlm_lockspace_t *lockspace, int force);
230
231/*
232 * dlm_lock
233 *
234 * Make an asyncronous request to acquire or convert a lock on a named
235 * resource.
236 *
237 * lockspace: context for the request
238 * mode: the requested mode of the lock (DLM_LOCK_)
239 * lksb: lock status block for input and async return values
240 * flags: input flags (DLM_LKF_)
241 * name: name of the resource to lock, can be binary
242 * namelen: the length in bytes of the resource name (MAX_RESNAME_LEN)
243 * parent: the lock ID of a parent lock or 0 if none
244 * lockast: function DLM executes when it completes processing the request
245 * astarg: argument passed to lockast and bast functions
246 * bast: function DLM executes when this lock later blocks another request
247 *
248 * Returns:
249 * 0 if request is successfully queued for processing
250 * -EINVAL if any input parameters are invalid
251 * -EAGAIN if request would block and is flagged DLM_LKF_NOQUEUE
252 * -ENOMEM if there is no memory to process request
253 * -ENOTCONN if there is a communication error
254 *
255 * If the call to dlm_lock returns an error then the operation has failed and
256 * the AST routine will not be called. If dlm_lock returns 0 it is still
257 * possible that the lock operation will fail. The AST routine will be called
258 * when the locking is complete and the status is returned in the lksb.
259 *
260 * If the AST routines or parameter are passed to a conversion operation then
261 * they will overwrite those values that were passed to a previous dlm_lock
262 * call.
263 *
264 * AST routines should not block (at least not for long), but may make
265 * any locking calls they please.
266 */
267
268int dlm_lock(dlm_lockspace_t *lockspace,
269 int mode,
270 struct dlm_lksb *lksb,
271 uint32_t flags,
272 void *name,
273 unsigned int namelen,
274 uint32_t parent_lkid,
275 void (*lockast) (void *astarg),
276 void *astarg,
277 void (*bast) (void *astarg, int mode));
278
279/*
280 * dlm_unlock
281 *
282 * Asynchronously release a lock on a resource. The AST routine is called
283 * when the resource is successfully unlocked.
284 *
285 * lockspace: context for the request
286 * lkid: the lock ID as returned in the lksb
287 * flags: input flags (DLM_LKF_)
288 * lksb: if NULL the lksb parameter passed to last lock request is used
289 * astarg: the arg used with the completion ast for the unlock
290 *
291 * Returns:
292 * 0 if request is successfully queued for processing
293 * -EINVAL if any input parameters are invalid
294 * -ENOTEMPTY if the lock still has sublocks
295 * -EBUSY if the lock is waiting for a remote lock operation
296 * -ENOTCONN if there is a communication error
297 */
298
299int dlm_unlock(dlm_lockspace_t *lockspace,
300 uint32_t lkid,
301 uint32_t flags,
302 struct dlm_lksb *lksb,
303 void *astarg);
304
305#endif /* __KERNEL__ */
306
307#endif /* __DLM_DOT_H__ */
308