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
  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  * -DLM_EUNLOCK if unlock request was successful
  52  * -DLM_ECANCEL if a cancel completed successfully
  53  * -EDEADLK if a deadlock was detected
  54  * -ETIMEDOUT if the lock request was canceled due to a timeout
  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 /* dlm_new_lockspace() flags */
  69
  70 #define DLM_LSFL_TIMEWARN       0x00000002
  71 #define DLM_LSFL_FS             0x00000004
  72 #define DLM_LSFL_NEWEXCL        0x00000008
  73
  74 #ifdef __KERNEL__
  75
  76 struct dlm_slot {
  77         int nodeid; /* 1 to MAX_INT */
  78         int slot;   /* 1 to MAX_INT */
  79 };
  80
  81 /*
  82  * recover_prep: called before the dlm begins lock recovery.
  83  *   Notfies lockspace user that locks from failed members will be granted.
  84  * recover_slot: called after recover_prep and before recover_done.
  85  *   Identifies a failed lockspace member.
  86  * recover_done: called after the dlm completes lock recovery.
  87  *   Identifies lockspace members and lockspace generation number.
  88  */
  89
  90 struct dlm_lockspace_ops {
  91         void (*recover_prep) (void *ops_arg);
  92         void (*recover_slot) (void *ops_arg, struct dlm_slot *slot);
  93         void (*recover_done) (void *ops_arg, struct dlm_slot *slots,
  94                               int num_slots, int our_slot, uint32_t generation);
  95 };
  96
  97 /*
  98  * dlm_new_lockspace
  99  *
 100  * Create/join a lockspace.
 101  *
 102  * name: lockspace name, null terminated, up to DLM_LOCKSPACE_LEN (not
 103  *   including terminating null).
 104  *
 105  * cluster: cluster name, null terminated, up to DLM_LOCKSPACE_LEN (not
 106  *   including terminating null).  Optional.  When cluster is null, it
 107  *   is not used.  When set, dlm_new_lockspace() returns -EBADR if cluster
 108  *   is not equal to the dlm cluster name.
 109  *
 110  * flags:
 111  * DLM_LSFL_NODIR
 112  *   The dlm should not use a resource directory, but statically assign
 113  *   resource mastery to nodes based on the name hash that is otherwise
 114  *   used to select the directory node.  Must be the same on all nodes.
 115  * DLM_LSFL_TIMEWARN
 116  *   The dlm should emit netlink messages if locks have been waiting
 117  *   for a configurable amount of time.  (Unused.)
 118  * DLM_LSFL_FS
 119  *   The lockspace user is in the kernel (i.e. filesystem).  Enables
 120  *   direct bast/cast callbacks.
 121  * DLM_LSFL_NEWEXCL
 122  *   dlm_new_lockspace() should return -EEXIST if the lockspace exists.
 123  *
 124  * lvblen: length of lvb in bytes.  Must be multiple of 8.
 125  *   dlm_new_lockspace() returns an error if this does not match
 126  *   what other nodes are using.
 127  *
 128  * ops: callbacks that indicate lockspace recovery points so the
 129  *   caller can coordinate its recovery and know lockspace members.
 130  *   This is only used by the initial dlm_new_lockspace() call.
 131  *   Optional.
 132  *
 133  * ops_arg: arg for ops callbacks.
 134  *
 135  * ops_result: tells caller if the ops callbacks (if provided) will
 136  *   be used or not.  0: will be used, -EXXX will not be used.
 137  *   -EOPNOTSUPP: the dlm does not have recovery_callbacks enabled.
 138  *
 139  * lockspace: handle for dlm functions
 140  */
 141
 142 int dlm_new_lockspace(const char *name, const char *cluster,
 143                       uint32_t flags, int lvblen,
 144                       const struct dlm_lockspace_ops *ops, void *ops_arg,
 145                       int *ops_result, dlm_lockspace_t **lockspace);
 146
 147 /*
 148  * dlm_release_lockspace
 149  *
 150  * Stop a lockspace.
 151  */
 152
 153 int dlm_release_lockspace(dlm_lockspace_t *lockspace, int force);
 154
 155 /*
 156  * dlm_lock
 157  *
 158  * Make an asyncronous request to acquire or convert a lock on a named
 159  * resource.
 160  *
 161  * lockspace: context for the request
 162  * mode: the requested mode of the lock (DLM_LOCK_)
 163  * lksb: lock status block for input and async return values
 164  * flags: input flags (DLM_LKF_)
 165  * name: name of the resource to lock, can be binary
 166  * namelen: the length in bytes of the resource name (MAX_RESNAME_LEN)
 167  * parent: the lock ID of a parent lock or 0 if none
 168  * lockast: function DLM executes when it completes processing the request
 169  * astarg: argument passed to lockast and bast functions
 170  * bast: function DLM executes when this lock later blocks another request
 171  *
 172  * Returns:
 173  * 0 if request is successfully queued for processing
 174  * -EINVAL if any input parameters are invalid
 175  * -EAGAIN if request would block and is flagged DLM_LKF_NOQUEUE
 176  * -ENOMEM if there is no memory to process request
 177  * -ENOTCONN if there is a communication error
 178  *
 179  * If the call to dlm_lock returns an error then the operation has failed and
 180  * the AST routine will not be called.  If dlm_lock returns 0 it is still
 181  * possible that the lock operation will fail. The AST routine will be called
 182  * when the locking is complete and the status is returned in the lksb.
 183  *
 184  * If the AST routines or parameter are passed to a conversion operation then
 185  * they will overwrite those values that were passed to a previous dlm_lock
 186  * call.
 187  *
 188  * AST routines should not block (at least not for long), but may make
 189  * any locking calls they please.
 190  */
 191
 192 int dlm_lock(dlm_lockspace_t *lockspace,
 193              int mode,
 194              struct dlm_lksb *lksb,
 195              uint32_t flags,
 196              void *name,
 197              unsigned int namelen,
 198              uint32_t parent_lkid,
 199              void (*lockast) (void *astarg),
 200              void *astarg,
 201              void (*bast) (void *astarg, int mode));
 202
 203 /*
 204  * dlm_unlock
 205  *
 206  * Asynchronously release a lock on a resource.  The AST routine is called
 207  * when the resource is successfully unlocked.
 208  *
 209  * lockspace: context for the request
 210  * lkid: the lock ID as returned in the lksb
 211  * flags: input flags (DLM_LKF_)
 212  * lksb: if NULL the lksb parameter passed to last lock request is used
 213  * astarg: the arg used with the completion ast for the unlock
 214  *
 215  * Returns:
 216  * 0 if request is successfully queued for processing
 217  * -EINVAL if any input parameters are invalid
 218  * -ENOTEMPTY if the lock still has sublocks
 219  * -EBUSY if the lock is waiting for a remote lock operation
 220  * -ENOTCONN if there is a communication error
 221  */
 222
 223 int dlm_unlock(dlm_lockspace_t *lockspace,
 224                uint32_t lkid,
 225                uint32_t flags,
 226                struct dlm_lksb *lksb,
 227                void *astarg);
 228
 229 #endif                          /* __KERNEL__ */
 230
 231 #endif                          /* __DLM_DOT_H__ */
 232