include/linux/dlm.h

   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
  19 struct 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
  33 struct 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
  85 int 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
  96 int 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
 135 int 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
 166 int 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__ */