linux/include/linux/dlm.h
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   1/******************************************************************************
   2*******************************************************************************
   3**
   4**  Copyright (C) Sistina Software, Inc.  1997-2003  All rights reserved.
   5**  Copyright (C) 2004-2011 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#ifndef __DLM_DOT_H__
  14#define __DLM_DOT_H__
  15
  16#include <uapi/linux/dlm.h>
  17
  18
  19struct dlm_slot {
  20        int nodeid; /* 1 to MAX_INT */
  21        int slot;   /* 1 to MAX_INT */
  22};
  23
  24/*
  25 * recover_prep: called before the dlm begins lock recovery.
  26 *   Notfies lockspace user that locks from failed members will be granted.
  27 * recover_slot: called after recover_prep and before recover_done.
  28 *   Identifies a failed lockspace member.
  29 * recover_done: called after the dlm completes lock recovery.
  30 *   Identifies lockspace members and lockspace generation number.
  31 */
  32
  33struct dlm_lockspace_ops {
  34        void (*recover_prep) (void *ops_arg);
  35        void (*recover_slot) (void *ops_arg, struct dlm_slot *slot);
  36        void (*recover_done) (void *ops_arg, struct dlm_slot *slots,
  37                              int num_slots, int our_slot, uint32_t generation);
  38};
  39
  40/*
  41 * dlm_new_lockspace
  42 *
  43 * Create/join a lockspace.
  44 *
  45 * name: lockspace name, null terminated, up to DLM_LOCKSPACE_LEN (not
  46 *   including terminating null).
  47 *
  48 * cluster: cluster name, null terminated, up to DLM_LOCKSPACE_LEN (not
  49 *   including terminating null).  Optional.  When cluster is null, it
  50 *   is not used.  When set, dlm_new_lockspace() returns -EBADR if cluster
  51 *   is not equal to the dlm cluster name.
  52 *
  53 * flags:
  54 * DLM_LSFL_NODIR
  55 *   The dlm should not use a resource directory, but statically assign
  56 *   resource mastery to nodes based on the name hash that is otherwise
  57 *   used to select the directory node.  Must be the same on all nodes.
  58 * DLM_LSFL_TIMEWARN
  59 *   The dlm should emit netlink messages if locks have been waiting
  60 *   for a configurable amount of time.  (Unused.)
  61 * DLM_LSFL_FS
  62 *   The lockspace user is in the kernel (i.e. filesystem).  Enables
  63 *   direct bast/cast callbacks.
  64 * DLM_LSFL_NEWEXCL
  65 *   dlm_new_lockspace() should return -EEXIST if the lockspace exists.
  66 *
  67 * lvblen: length of lvb in bytes.  Must be multiple of 8.
  68 *   dlm_new_lockspace() returns an error if this does not match
  69 *   what other nodes are using.
  70 *
  71 * ops: callbacks that indicate lockspace recovery points so the
  72 *   caller can coordinate its recovery and know lockspace members.
  73 *   This is only used by the initial dlm_new_lockspace() call.
  74 *   Optional.
  75 *
  76 * ops_arg: arg for ops callbacks.
  77 *
  78 * ops_result: tells caller if the ops callbacks (if provided) will
  79 *   be used or not.  0: will be used, -EXXX will not be used.
  80 *   -EOPNOTSUPP: the dlm does not have recovery_callbacks enabled.
  81 *
  82 * lockspace: handle for dlm functions
  83 */
  84
  85int dlm_new_lockspace(const char *name, const char *cluster,
  86                      uint32_t flags, int lvblen,
  87                      const struct dlm_lockspace_ops *ops, void *ops_arg,
  88                      int *ops_result, dlm_lockspace_t **lockspace);
  89
  90/*
  91 * dlm_release_lockspace
  92 *
  93 * Stop a lockspace.
  94 */
  95
  96int dlm_release_lockspace(dlm_lockspace_t *lockspace, int force);
  97
  98/*
  99 * dlm_lock
 100 *
 101 * Make an asynchronous request to acquire or convert a lock on a named
 102 * resource.
 103 *
 104 * lockspace: context for the request
 105 * mode: the requested mode of the lock (DLM_LOCK_)
 106 * lksb: lock status block for input and async return values
 107 * flags: input flags (DLM_LKF_)
 108 * name: name of the resource to lock, can be binary
 109 * namelen: the length in bytes of the resource name (MAX_RESNAME_LEN)
 110 * parent: the lock ID of a parent lock or 0 if none
 111 * lockast: function DLM executes when it completes processing the request
 112 * astarg: argument passed to lockast and bast functions
 113 * bast: function DLM executes when this lock later blocks another request
 114 *
 115 * Returns:
 116 * 0 if request is successfully queued for processing
 117 * -EINVAL if any input parameters are invalid
 118 * -EAGAIN if request would block and is flagged DLM_LKF_NOQUEUE
 119 * -ENOMEM if there is no memory to process request
 120 * -ENOTCONN if there is a communication error
 121 *
 122 * If the call to dlm_lock returns an error then the operation has failed and
 123 * the AST routine will not be called.  If dlm_lock returns 0 it is still
 124 * possible that the lock operation will fail. The AST routine will be called
 125 * when the locking is complete and the status is returned in the lksb.
 126 *
 127 * If the AST routines or parameter are passed to a conversion operation then
 128 * they will overwrite those values that were passed to a previous dlm_lock
 129 * call.
 130 *
 131 * AST routines should not block (at least not for long), but may make
 132 * any locking calls they please.
 133 */
 134
 135int dlm_lock(dlm_lockspace_t *lockspace,
 136             int mode,
 137             struct dlm_lksb *lksb,
 138             uint32_t flags,
 139             void *name,
 140             unsigned int namelen,
 141             uint32_t parent_lkid,
 142             void (*lockast) (void *astarg),
 143             void *astarg,
 144             void (*bast) (void *astarg, int mode));
 145
 146/*
 147 * dlm_unlock
 148 *
 149 * Asynchronously release a lock on a resource.  The AST routine is called
 150 * when the resource is successfully unlocked.
 151 *
 152 * lockspace: context for the request
 153 * lkid: the lock ID as returned in the lksb
 154 * flags: input flags (DLM_LKF_)
 155 * lksb: if NULL the lksb parameter passed to last lock request is used
 156 * astarg: the arg used with the completion ast for the unlock
 157 *
 158 * Returns:
 159 * 0 if request is successfully queued for processing
 160 * -EINVAL if any input parameters are invalid
 161 * -ENOTEMPTY if the lock still has sublocks
 162 * -EBUSY if the lock is waiting for a remote lock operation
 163 * -ENOTCONN if there is a communication error
 164 */
 165
 166int dlm_unlock(dlm_lockspace_t *lockspace,
 167               uint32_t lkid,
 168               uint32_t flags,
 169               struct dlm_lksb *lksb,
 170               void *astarg);
 171
 172#endif                          /* __DLM_DOT_H__ */
 173
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