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
  25
  26 #define DLM_RESNAME_MAXLEN      64
  27
  28
  29 typedef void dlm_lockspace_t;
  30
  31 /*
  32  * Lock status block
  33  *
  34  * Use this structure to specify the contents of the lock value block.  For a
  35  * conversion request, this structure is used to specify the lock ID of the
  36  * lock.  DLM writes the status of the lock request and the lock ID assigned
  37  * to the request in the lock status block.
  38  *
  39  * sb_lkid: the returned lock ID.  It is set on new (non-conversion) requests.
  40  * It is available when dlm_lock returns.
  41  *
  42  * sb_lvbptr: saves or returns the contents of the lock's LVB according to rules
  43  * shown for the DLM_LKF_VALBLK flag.
  44  *
  45  * sb_flags: DLM_SBF_DEMOTED is returned if in the process of promoting a lock,
  46  * it was first demoted to NL to avoid conversion deadlock.
  47  * DLM_SBF_VALNOTVALID is returned if the resource's LVB is marked invalid.
  48  *
  49  * sb_status: the returned status of the lock request set prior to AST
  50  * execution.  Possible return values:
  51  *
  52  * 0 if lock request was successful
  53  * -EAGAIN if request would block and is flagged DLM_LKF_NOQUEUE
  54  * -ENOMEM if there is no memory to process request
  55  * -EINVAL if there are invalid parameters
  56  * -DLM_EUNLOCK if unlock request was successful
  57  * -DLM_ECANCEL if a cancel completed successfully
  58  */
  59
  60 #define DLM_SBF_DEMOTED         0x01
  61 #define DLM_SBF_VALNOTVALID     0x02
  62 #define DLM_SBF_ALTMODE         0x04
  63
  64 struct dlm_lksb {
  65         int      sb_status;
  66         uint32_t sb_lkid;
  67         char     sb_flags;
  68         char *   sb_lvbptr;
  69 };
  70
  71 #define DLM_LSFL_NODIR          0x00000001
  72 #define DLM_LSFL_TIMEWARN       0x00000002
  73 #define DLM_LSFL_FS             0x00000004
  74
  75 #ifdef __KERNEL__
  76
  77 /*
  78  * dlm_new_lockspace
  79  *
  80  * Starts a lockspace with the given name.  If the named lockspace exists in
  81  * the cluster, the calling node joins it.
  82  */
  83
  84 int dlm_new_lockspace(char *name, int namelen, dlm_lockspace_t **lockspace,
  85                       uint32_t flags, int lvblen);
  86
  87 /*
  88  * dlm_release_lockspace
  89  *
  90  * Stop a lockspace.
  91  */
  92
  93 int dlm_release_lockspace(dlm_lockspace_t *lockspace, int force);
  94
  95 /*
  96  * dlm_lock
  97  *
  98  * Make an asyncronous request to acquire or convert a lock on a named
  99  * resource.
 100  *
 101  * lockspace: context for the request
 102  * mode: the requested mode of the lock (DLM_LOCK_)
 103  * lksb: lock status block for input and async return values
 104  * flags: input flags (DLM_LKF_)
 105  * name: name of the resource to lock, can be binary
 106  * namelen: the length in bytes of the resource name (MAX_RESNAME_LEN)
 107  * parent: the lock ID of a parent lock or 0 if none
 108  * lockast: function DLM executes when it completes processing the request
 109  * astarg: argument passed to lockast and bast functions
 110  * bast: function DLM executes when this lock later blocks another request
 111  *
 112  * Returns:
 113  * 0 if request is successfully queued for processing
 114  * -EINVAL if any input parameters are invalid
 115  * -EAGAIN if request would block and is flagged DLM_LKF_NOQUEUE
 116  * -ENOMEM if there is no memory to process request
 117  * -ENOTCONN if there is a communication error
 118  *
 119  * If the call to dlm_lock returns an error then the operation has failed and
 120  * the AST routine will not be called.  If dlm_lock returns 0 it is still
 121  * possible that the lock operation will fail. The AST routine will be called
 122  * when the locking is complete and the status is returned in the lksb.
 123  *
 124  * If the AST routines or parameter are passed to a conversion operation then
 125  * they will overwrite those values that were passed to a previous dlm_lock
 126  * call.
 127  *
 128  * AST routines should not block (at least not for long), but may make
 129  * any locking calls they please.
 130  */
 131
 132 int dlm_lock(dlm_lockspace_t *lockspace,
 133              int mode,
 134              struct dlm_lksb *lksb,
 135              uint32_t flags,
 136              void *name,
 137              unsigned int namelen,
 138              uint32_t parent_lkid,
 139              void (*lockast) (void *astarg),
 140              void *astarg,
 141              void (*bast) (void *astarg, int mode));
 142
 143 /*
 144  * dlm_unlock
 145  *
 146  * Asynchronously release a lock on a resource.  The AST routine is called
 147  * when the resource is successfully unlocked.
 148  *
 149  * lockspace: context for the request
 150  * lkid: the lock ID as returned in the lksb
 151  * flags: input flags (DLM_LKF_)
 152  * lksb: if NULL the lksb parameter passed to last lock request is used
 153  * astarg: the arg used with the completion ast for the unlock
 154  *
 155  * Returns:
 156  * 0 if request is successfully queued for processing
 157  * -EINVAL if any input parameters are invalid
 158  * -ENOTEMPTY if the lock still has sublocks
 159  * -EBUSY if the lock is waiting for a remote lock operation
 160  * -ENOTCONN if there is a communication error
 161  */
 162
 163 int dlm_unlock(dlm_lockspace_t *lockspace,
 164                uint32_t lkid,
 165                uint32_t flags,
 166                struct dlm_lksb *lksb,
 167                void *astarg);
 168
 169 #endif                          /* __KERNEL__ */
 170
 171 #endif                          /* __DLM_DOT_H__ */
 172