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