include/linux/lm_interface.h

   1 /*
   2  * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
   3  * Copyright (C) 2004-2006 Red Hat, Inc.  All rights reserved.
   4  *
   5  * This copyrighted material is made available to anyone wishing to use,
   6  * modify, copy, or redistribute it subject to the terms and conditions
   7  * of the GNU General Public License version 2.
   8  */
   9
  10 #ifndef __LM_INTERFACE_DOT_H__
  11 #define __LM_INTERFACE_DOT_H__
  12
  13
  14 typedef void (*lm_callback_t) (void *ptr, unsigned int type, void *data);
  15
  16 /*
  17  * lm_mount() flags
  18  *
  19  * LM_MFLAG_SPECTATOR
  20  * GFS is asking to join the filesystem's lockspace, but it doesn't want to
  21  * modify the filesystem.  The lock module shouldn't assign a journal to the FS
  22  * mount.  It shouldn't send recovery callbacks to the FS mount.  If the node
  23  * dies or withdraws, all locks can be wiped immediately.
  24  *
  25  * LM_MFLAG_CONV_NODROP
  26  * Do not allow the dlm to internally resolve conversion deadlocks by demoting
  27  * the lock to unlocked and then reacquiring it in the requested mode. Instead,
  28  * it should cancel the request and return LM_OUT_CONV_DEADLK.
  29  */
  30
  31 #define LM_MFLAG_SPECTATOR      0x00000001
  32 #define LM_MFLAG_CONV_NODROP    0x00000002
  33
  34 /*
  35  * lm_lockstruct flags
  36  *
  37  * LM_LSFLAG_LOCAL
  38  * The lock_nolock module returns LM_LSFLAG_LOCAL to GFS, indicating that GFS
  39  * can make single-node optimizations.
  40  */
  41
  42 #define LM_LSFLAG_LOCAL         0x00000001
  43
  44 /*
  45  * lm_lockname types
  46  */
  47
  48 #define LM_TYPE_RESERVED        0x00
  49 #define LM_TYPE_NONDISK         0x01
  50 #define LM_TYPE_INODE           0x02
  51 #define LM_TYPE_RGRP            0x03
  52 #define LM_TYPE_META            0x04
  53 #define LM_TYPE_IOPEN           0x05
  54 #define LM_TYPE_FLOCK           0x06
  55 #define LM_TYPE_PLOCK           0x07
  56 #define LM_TYPE_QUOTA           0x08
  57 #define LM_TYPE_JOURNAL         0x09
  58
  59 /*
  60  * lm_lock() states
  61  *
  62  * SHARED is compatible with SHARED, not with DEFERRED or EX.
  63  * DEFERRED is compatible with DEFERRED, not with SHARED or EX.
  64  */
  65
  66 #define LM_ST_UNLOCKED          0
  67 #define LM_ST_EXCLUSIVE         1
  68 #define LM_ST_DEFERRED          2
  69 #define LM_ST_SHARED            3
  70
  71 /*
  72  * lm_lock() flags
  73  *
  74  * LM_FLAG_TRY
  75  * Don't wait to acquire the lock if it can't be granted immediately.
  76  *
  77  * LM_FLAG_TRY_1CB
  78  * Send one blocking callback if TRY is set and the lock is not granted.
  79  *
  80  * LM_FLAG_NOEXP
  81  * GFS sets this flag on lock requests it makes while doing journal recovery.
  82  * These special requests should not be blocked due to the recovery like
  83  * ordinary locks would be.
  84  *
  85  * LM_FLAG_ANY
  86  * A SHARED request may also be granted in DEFERRED, or a DEFERRED request may
  87  * also be granted in SHARED.  The preferred state is whichever is compatible
  88  * with other granted locks, or the specified state if no other locks exist.
  89  *
  90  * LM_FLAG_PRIORITY
  91  * Override fairness considerations.  Suppose a lock is held in a shared state
  92  * and there is a pending request for the deferred state.  A shared lock
  93  * request with the priority flag would be allowed to bypass the deferred
  94  * request and directly join the other shared lock.  A shared lock request
  95  * without the priority flag might be forced to wait until the deferred
  96  * requested had acquired and released the lock.
  97  */
  98
  99 #define LM_FLAG_TRY             0x00000001
 100 #define LM_FLAG_TRY_1CB         0x00000002
 101 #define LM_FLAG_NOEXP           0x00000004
 102 #define LM_FLAG_ANY             0x00000008
 103 #define LM_FLAG_PRIORITY        0x00000010
 104
 105 /*
 106  * lm_lock() and lm_async_cb return flags
 107  *
 108  * LM_OUT_ST_MASK
 109  * Masks the lower two bits of lock state in the returned value.
 110  *
 111  * LM_OUT_CACHEABLE
 112  * The lock hasn't been released so GFS can continue to cache data for it.
 113  *
 114  * LM_OUT_CANCELED
 115  * The lock request was canceled.
 116  *
 117  * LM_OUT_ASYNC
 118  * The result of the request will be returned in an LM_CB_ASYNC callback.
 119  *
 120  * LM_OUT_CONV_DEADLK
 121  * The lock request was canceled do to a conversion deadlock.
 122  */
 123
 124 #define LM_OUT_ST_MASK          0x00000003
 125 #define LM_OUT_CANCELED         0x00000008
 126 #define LM_OUT_ASYNC            0x00000080
 127 #define LM_OUT_ERROR            0x00000100
 128
 129 /*
 130  * lm_callback_t types
 131  *
 132  * LM_CB_NEED_E LM_CB_NEED_D LM_CB_NEED_S
 133  * Blocking callback, a remote node is requesting the given lock in
 134  * EXCLUSIVE, DEFERRED, or SHARED.
 135  *
 136  * LM_CB_NEED_RECOVERY
 137  * The given journal needs to be recovered.
 138  *
 139  * LM_CB_ASYNC
 140  * The given lock has been granted.
 141  */
 142
 143 #define LM_CB_NEED_E            257
 144 #define LM_CB_NEED_D            258
 145 #define LM_CB_NEED_S            259
 146 #define LM_CB_NEED_RECOVERY     260
 147 #define LM_CB_ASYNC             262
 148
 149 /*
 150  * lm_recovery_done() messages
 151  */
 152
 153 #define LM_RD_GAVEUP            308
 154 #define LM_RD_SUCCESS           309
 155
 156
 157 struct lm_lockname {
 158         u64 ln_number;
 159         unsigned int ln_type;
 160 };
 161
 162 #define lm_name_equal(name1, name2) \
 163         (((name1)->ln_number == (name2)->ln_number) && \
 164          ((name1)->ln_type == (name2)->ln_type)) \
 165
 166 struct lm_async_cb {
 167         struct lm_lockname lc_name;
 168         int lc_ret;
 169 };
 170
 171 struct lm_lockstruct;
 172
 173 struct lm_lockops {
 174         const char *lm_proto_name;
 175
 176         /*
 177          * Mount/Unmount
 178          */
 179
 180         int (*lm_mount) (char *table_name, char *host_data,
 181                          lm_callback_t cb, void *cb_data,
 182                          unsigned int min_lvb_size, int flags,
 183                          struct lm_lockstruct *lockstruct,
 184                          struct kobject *fskobj);
 185
 186         void (*lm_others_may_mount) (void *lockspace);
 187
 188         void (*lm_unmount) (void *lockspace);
 189
 190         void (*lm_withdraw) (void *lockspace);
 191
 192         /*
 193          * Lock oriented operations
 194          */
 195
 196         int (*lm_get_lock) (void *lockspace, struct lm_lockname *name, void **lockp);
 197
 198         void (*lm_put_lock) (void *lock);
 199
 200         unsigned int (*lm_lock) (void *lock, unsigned int cur_state,
 201                                  unsigned int req_state, unsigned int flags);
 202
 203         unsigned int (*lm_unlock) (void *lock, unsigned int cur_state);
 204
 205         void (*lm_cancel) (void *lock);
 206
 207         int (*lm_hold_lvb) (void *lock, char **lvbp);
 208         void (*lm_unhold_lvb) (void *lock, char *lvb);
 209
 210         /*
 211          * Posix Lock oriented operations
 212          */
 213
 214         int (*lm_plock_get) (void *lockspace, struct lm_lockname *name,
 215                              struct file *file, struct file_lock *fl);
 216
 217         int (*lm_plock) (void *lockspace, struct lm_lockname *name,
 218                          struct file *file, int cmd, struct file_lock *fl);
 219
 220         int (*lm_punlock) (void *lockspace, struct lm_lockname *name,
 221                            struct file *file, struct file_lock *fl);
 222
 223         /*
 224          * Client oriented operations
 225          */
 226
 227         void (*lm_recovery_done) (void *lockspace, unsigned int jid,
 228                                   unsigned int message);
 229
 230         struct module *lm_owner;
 231 };
 232
 233 /*
 234  * lm_mount() return values
 235  *
 236  * ls_jid - the journal ID this node should use
 237  * ls_first - this node is the first to mount the file system
 238  * ls_lvb_size - size in bytes of lock value blocks
 239  * ls_lockspace - lock module's context for this file system
 240  * ls_ops - lock module's functions
 241  * ls_flags - lock module features
 242  */
 243
 244 struct lm_lockstruct {
 245         unsigned int ls_jid;
 246         unsigned int ls_first;
 247         unsigned int ls_lvb_size;
 248         void *ls_lockspace;
 249         const struct lm_lockops *ls_ops;
 250         int ls_flags;
 251 };
 252
 253 /*
 254  * Lock module bottom interface.  A lock module makes itself available to GFS
 255  * with these functions.
 256  */
 257
 258 int gfs2_register_lockproto(const struct lm_lockops *proto);
 259 void gfs2_unregister_lockproto(const struct lm_lockops *proto);
 260
 261 /*
 262  * Lock module top interface.  GFS calls these functions when mounting or
 263  * unmounting a file system.
 264  */
 265
 266 int gfs2_mount_lockproto(char *proto_name, char *table_name, char *host_data,
 267                          lm_callback_t cb, void *cb_data,
 268                          unsigned int min_lvb_size, int flags,
 269                          struct lm_lockstruct *lockstruct,
 270                          struct kobject *fskobj);
 271
 272 void gfs2_unmount_lockproto(struct lm_lockstruct *lockstruct);
 273
 274 void gfs2_withdraw_lockproto(struct lm_lockstruct *lockstruct);
 275
 276 #endif /* __LM_INTERFACE_DOT_H__ */
 277