include/linux/dlm.h

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2 /******************************************************************************
   3 *******************************************************************************
   4 **
   5 **  Copyright (C) Sistina Software, Inc.  1997-2003  All rights reserved.
   6 **  Copyright (C) 2004-2011 Red Hat, Inc.  All rights reserved.
   7 **
   8 **
   9 *******************************************************************************
  10 ******************************************************************************/
  11 #ifndef __DLM_DOT_H__
  12 #define __DLM_DOT_H__
  13
  14 #include <uapi/linux/dlm.h>
  15
  16
  17 struct dlm_slot {
  18         int nodeid; /* 1 to MAX_INT */
  19         int slot;   /* 1 to MAX_INT */
  20 };
  21
  22 /*
  23  * recover_prep: called before the dlm begins lock recovery.
  24  *   Notfies lockspace user that locks from failed members will be granted.
  25  * recover_slot: called after recover_prep and before recover_done.
  26  *   Identifies a failed lockspace member.
  27  * recover_done: called after the dlm completes lock recovery.
  28  *   Identifies lockspace members and lockspace generation number.
  29  */
  30
  31 struct dlm_lockspace_ops {
  32         void (*recover_prep) (void *ops_arg);
  33         void (*recover_slot) (void *ops_arg, struct dlm_slot *slot);
  34         void (*recover_done) (void *ops_arg, struct dlm_slot *slots,
  35                               int num_slots, int our_slot, uint32_t generation);
  36 };
  37
  38 /* only relevant for kernel lockspaces, will be removed in future */
  39 #define DLM_LSFL_SOFTIRQ __DLM_LSFL_RESERVED0
  40
  41 /*
  42  * dlm_new_lockspace
  43  *
  44  * Create/join a lockspace.
  45  *
  46  * name: lockspace name, null terminated, up to DLM_LOCKSPACE_LEN (not
  47  *   including terminating null).
  48  *
  49  * cluster: cluster name, null terminated, up to DLM_LOCKSPACE_LEN (not
  50  *   including terminating null).  Optional.  When cluster is null, it
  51  *   is not used.  When set, dlm_new_lockspace() returns -EBADR if cluster
  52  *   is not equal to the dlm cluster name.
  53  *
  54  * flags:
  55  * DLM_LSFL_NODIR
  56  *   The dlm should not use a resource directory, but statically assign
  57  *   resource mastery to nodes based on the name hash that is otherwise
  58  *   used to select the directory node.  Must be the same on all nodes.
  59  * DLM_LSFL_NEWEXCL
  60  *   dlm_new_lockspace() should return -EEXIST if the lockspace exists.
  61  * DLM_LSFL_SOFTIRQ
  62  *   dlm request callbacks (ast, bast) are softirq safe. Flag should be
  63  *   preferred by users. Will be default in some future. If set the
  64  *   strongest context for ast, bast callback is softirq as it avoids
  65  *   an additional context switch.
  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. If DLM_LSFL_SOFTIRQ for kernel
 133  * users of dlm_new_lockspace() is passed the ast and bast callbacks
 134  * can be processed in softirq context. Also some of the callback
 135  * contexts are in the same context as the DLM lock request API, users
 136  * must not hold locks while calling dlm lock request API and trying
 137  * to acquire this lock in the callback again, this will end in a
 138  * lock recursion. For newer implementation the DLM_LSFL_SOFTIRQ
 139  * should be used.
 140  */
 141
 142 int dlm_lock(dlm_lockspace_t *lockspace,
 143              int mode,
 144              struct dlm_lksb *lksb,
 145              uint32_t flags,
 146              const void *name,
 147              unsigned int namelen,
 148              uint32_t parent_lkid,
 149              void (*lockast) (void *astarg),
 150              void *astarg,
 151              void (*bast) (void *astarg, int mode));
 152
 153 /*
 154  * dlm_unlock
 155  *
 156  * Asynchronously release a lock on a resource.  The AST routine is called
 157  * when the resource is successfully unlocked.
 158  *
 159  * lockspace: context for the request
 160  * lkid: the lock ID as returned in the lksb
 161  * flags: input flags (DLM_LKF_)
 162  * lksb: if NULL the lksb parameter passed to last lock request is used
 163  * astarg: the arg used with the completion ast for the unlock
 164  *
 165  * Returns:
 166  * 0 if request is successfully queued for processing
 167  * -EINVAL if any input parameters are invalid
 168  * -ENOTEMPTY if the lock still has sublocks
 169  * -EBUSY if the lock is waiting for a remote lock operation
 170  * -ENOTCONN if there is a communication error
 171  */
 172
 173 int dlm_unlock(dlm_lockspace_t *lockspace,
 174                uint32_t lkid,
 175                uint32_t flags,
 176                struct dlm_lksb *lksb,
 177                void *astarg);
 178
 179 #endif                          /* __DLM_DOT_H__ */