include/linux/dlm.h

   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 /* Lock levels and flags are here */
  23 #include <linux/dlmconstants.h>
  24 #include <linux/types.h>
  25
  26 typedef void dlm_lockspace_t;
  27
  28 /*
  29  * Lock status block
  30  *
  31  * Use this structure to specify the contents of the lock value block.  For a
  32  * conversion request, this structure is used to specify the lock ID of the
  33  * lock.  DLM writes the status of the lock request and the lock ID assigned
  34  * to the request in the lock status block.
  35  *
  36  * sb_lkid: the returned lock ID.  It is set on new (non-conversion) requests.
  37  * It is available when dlm_lock returns.
  38  *
  39  * sb_lvbptr: saves or returns the contents of the lock's LVB according to rules
  40  * shown for the DLM_LKF_VALBLK flag.
  41  *
  42  * sb_flags: DLM_SBF_DEMOTED is returned if in the process of promoting a lock,
  43  * it was first demoted to NL to avoid conversion deadlock.
  44  * DLM_SBF_VALNOTVALID is returned if the resource's LVB is marked invalid.
  45  *
  46  * sb_status: the returned status of the lock request set prior to AST
  47  * execution.  Possible return values:
  48  *
  49  * 0 if lock request was successful
  50  * -EAGAIN if request would block and is flagged DLM_LKF_NOQUEUE
  51  * -ENOMEM if there is no memory to process request
  52  * -EINVAL if there are invalid parameters
  53  * -DLM_EUNLOCK if unlock request was successful
  54  * -DLM_ECANCEL if a cancel completed successfully
  55  */
  56
  57 #define DLM_SBF_DEMOTED         0x01
  58 #define DLM_SBF_VALNOTVALID     0x02
  59 #define DLM_SBF_ALTMODE         0x04
  60
  61 struct dlm_lksb {
  62         int      sb_status;
  63         __u32    sb_lkid;
  64         char     sb_flags;
  65         char *   sb_lvbptr;
  66 };
  67
  68 #define DLM_LSFL_NODIR          0x00000001
  69 #define DLM_LSFL_TIMEWARN       0x00000002
  70 #define DLM_LSFL_FS             0x00000004
  71
  72 #ifdef __KERNEL__
  73
  74 /*
  75  * dlm_new_lockspace
  76  *
  77  * Starts a lockspace with the given name.  If the named lockspace exists in
  78  * the cluster, the calling node joins it.
  79  */
  80
  81 int dlm_new_lockspace(char *name, int namelen, dlm_lockspace_t **lockspace,
  82                       uint32_t flags, int lvblen);
  83
  84 /*
  85  * dlm_release_lockspace
  86  *
  87  * Stop a lockspace.
  88  */
  89
  90 int dlm_release_lockspace(dlm_lockspace_t *lockspace, int force);
  91
  92 /*
  93  * dlm_lock
  94  *
  95  * Make an asyncronous request to acquire or convert a lock on a named
  96  * resource.
  97  *
  98  * lockspace: context for the request
  99  * mode: the requested mode of the lock (DLM_LOCK_)
 100  * lksb: lock status block for input and async return values
 101  * flags: input flags (DLM_LKF_)
 102  * name: name of the resource to lock, can be binary
 103  * namelen: the length in bytes of the resource name (MAX_RESNAME_LEN)
 104  * parent: the lock ID of a parent lock or 0 if none
 105  * lockast: function DLM executes when it completes processing the request
 106  * astarg: argument passed to lockast and bast functions
 107  * bast: function DLM executes when this lock later blocks another request
 108  *
 109  * Returns:
 110  * 0 if request is successfully queued for processing
 111  * -EINVAL if any input parameters are invalid
 112  * -EAGAIN if request would block and is flagged DLM_LKF_NOQUEUE
 113  * -ENOMEM if there is no memory to process request
 114  * -ENOTCONN if there is a communication error
 115  *
 116  * If the call to dlm_lock returns an error then the operation has failed and
 117  * the AST routine will not be called.  If dlm_lock returns 0 it is still
 118  * possible that the lock operation will fail. The AST routine will be called
 119  * when the locking is complete and the status is returned in the lksb.
 120  *
 121  * If the AST routines or parameter are passed to a conversion operation then
 122  * they will overwrite those values that were passed to a previous dlm_lock
 123  * call.
 124  *
 125  * AST routines should not block (at least not for long), but may make
 126  * any locking calls they please.
 127  */
 128
 129 int dlm_lock(dlm_lockspace_t *lockspace,
 130              int mode,
 131              struct dlm_lksb *lksb,
 132              uint32_t flags,
 133              void *name,
 134              unsigned int namelen,
 135              uint32_t parent_lkid,
 136              void (*lockast) (void *astarg),
 137              void *astarg,
 138              void (*bast) (void *astarg, int mode));
 139
 140 /*
 141  * dlm_unlock
 142  *
 143  * Asynchronously release a lock on a resource.  The AST routine is called
 144  * when the resource is successfully unlocked.
 145  *
 146  * lockspace: context for the request
 147  * lkid: the lock ID as returned in the lksb
 148  * flags: input flags (DLM_LKF_)
 149  * lksb: if NULL the lksb parameter passed to last lock request is used
 150  * astarg: the arg used with the completion ast for the unlock
 151  *
 152  * Returns:
 153  * 0 if request is successfully queued for processing
 154  * -EINVAL if any input parameters are invalid
 155  * -ENOTEMPTY if the lock still has sublocks
 156  * -EBUSY if the lock is waiting for a remote lock operation
 157  * -ENOTCONN if there is a communication error
 158  */
 159
 160 int dlm_unlock(dlm_lockspace_t *lockspace,
 161                uint32_t lkid,
 162                uint32_t flags,
 163                struct dlm_lksb *lksb,
 164                void *astarg);
 165
 166 #endif                          /* __KERNEL__ */
 167
 168 #endif                          /* __DLM_DOT_H__ */
 169