fs/gfs2/locking/nolock/main.c

   1 /*
   2  * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
   3  * Copyright (C) 2004-2005 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 v.2.
   8  */
   9
  10 #include <linux/module.h>
  11 #include <linux/slab.h>
  12 #include <linux/module.h>
  13 #include <linux/init.h>
  14 #include <linux/types.h>
  15 #include <linux/fs.h>
  16 #include <linux/smp_lock.h>
  17
  18 #include "../../lm_interface.h"
  19
  20 struct nolock_lockspace {
  21         unsigned int nl_lvb_size;
  22 };
  23
  24 struct lm_lockops nolock_ops;
  25
  26 static int nolock_mount(char *table_name, char *host_data,
  27                         lm_callback_t cb, lm_fsdata_t *fsdata,
  28                         unsigned int min_lvb_size, int flags,
  29                         struct lm_lockstruct *lockstruct,
  30                         struct kobject *fskobj)
  31 {
  32         char *c;
  33         unsigned int jid;
  34         struct nolock_lockspace *nl;
  35
  36         /* If there is a "jid=" in the hostdata, return that jid.
  37            Otherwise, return zero. */
  38
  39         c = strstr(host_data, "jid=");
  40         if (!c)
  41                 jid = 0;
  42         else {
  43                 c += 4;
  44                 sscanf(c, "%u", &jid);
  45         }
  46
  47         nl = kzalloc(sizeof(struct nolock_lockspace), GFP_KERNEL);
  48         if (!nl)
  49                 return -ENOMEM;
  50
  51         nl->nl_lvb_size = min_lvb_size;
  52
  53         lockstruct->ls_jid = jid;
  54         lockstruct->ls_first = 1;
  55         lockstruct->ls_lvb_size = min_lvb_size;
  56         lockstruct->ls_lockspace = (lm_lockspace_t *)nl;
  57         lockstruct->ls_ops = &nolock_ops;
  58         lockstruct->ls_flags = LM_LSFLAG_LOCAL;
  59
  60         return 0;
  61 }
  62
  63 static void nolock_others_may_mount(lm_lockspace_t *lockspace)
  64 {
  65 }
  66
  67 static void nolock_unmount(lm_lockspace_t *lockspace)
  68 {
  69         struct nolock_lockspace *nl = (struct nolock_lockspace *)lockspace;
  70         kfree(nl);
  71 }
  72
  73 static void nolock_withdraw(lm_lockspace_t *lockspace)
  74 {
  75 }
  76
  77 /**
  78  * nolock_get_lock - get a lm_lock_t given a descripton of the lock
  79  * @lockspace: the lockspace the lock lives in
  80  * @name: the name of the lock
  81  * @lockp: return the lm_lock_t here
  82  *
  83  * Returns: 0 on success, -EXXX on failure
  84  */
  85
  86 static int nolock_get_lock(lm_lockspace_t *lockspace, struct lm_lockname *name,
  87                            lm_lock_t **lockp)
  88 {
  89         *lockp = (lm_lock_t *)lockspace;
  90         return 0;
  91 }
  92
  93 /**
  94  * nolock_put_lock - get rid of a lock structure
  95  * @lock: the lock to throw away
  96  *
  97  */
  98
  99 static void nolock_put_lock(lm_lock_t *lock)
 100 {
 101 }
 102
 103 /**
 104  * nolock_lock - acquire a lock
 105  * @lock: the lock to manipulate
 106  * @cur_state: the current state
 107  * @req_state: the requested state
 108  * @flags: modifier flags
 109  *
 110  * Returns: A bitmap of LM_OUT_*
 111  */
 112
 113 static unsigned int nolock_lock(lm_lock_t *lock, unsigned int cur_state,
 114                                 unsigned int req_state, unsigned int flags)
 115 {
 116         return req_state | LM_OUT_CACHEABLE;
 117 }
 118
 119 /**
 120  * nolock_unlock - unlock a lock
 121  * @lock: the lock to manipulate
 122  * @cur_state: the current state
 123  *
 124  * Returns: 0
 125  */
 126
 127 static unsigned int nolock_unlock(lm_lock_t *lock, unsigned int cur_state)
 128 {
 129         return 0;
 130 }
 131
 132 static void nolock_cancel(lm_lock_t *lock)
 133 {
 134 }
 135
 136 /**
 137  * nolock_hold_lvb - hold on to a lock value block
 138  * @lock: the lock the LVB is associated with
 139  * @lvbp: return the lm_lvb_t here
 140  *
 141  * Returns: 0 on success, -EXXX on failure
 142  */
 143
 144 static int nolock_hold_lvb(lm_lock_t *lock, char **lvbp)
 145 {
 146         struct nolock_lockspace *nl = (struct nolock_lockspace *)lock;
 147         int error = 0;
 148
 149         *lvbp = kzalloc(nl->nl_lvb_size, GFP_KERNEL);
 150         if (!*lvbp)
 151                 error = -ENOMEM;
 152
 153         return error;
 154 }
 155
 156 /**
 157  * nolock_unhold_lvb - release a LVB
 158  * @lock: the lock the LVB is associated with
 159  * @lvb: the lock value block
 160  *
 161  */
 162
 163 static void nolock_unhold_lvb(lm_lock_t *lock, char *lvb)
 164 {
 165         kfree(lvb);
 166 }
 167
 168 /**
 169  * nolock_sync_lvb - sync out the value of a lvb
 170  * @lock: the lock the LVB is associated with
 171  * @lvb: the lock value block
 172  *
 173  */
 174
 175 static void nolock_sync_lvb(lm_lock_t *lock, char *lvb)
 176 {
 177 }
 178
 179 static int nolock_plock_get(lm_lockspace_t *lockspace, struct lm_lockname *name,
 180                             struct file *file, struct file_lock *fl)
 181 {
 182         struct file_lock *tmp;
 183
 184         lock_kernel();
 185         tmp = posix_test_lock(file, fl);
 186         fl->fl_type = F_UNLCK;
 187         if (tmp)
 188                 memcpy(fl, tmp, sizeof(struct file_lock));
 189         unlock_kernel();
 190
 191         return 0;
 192 }
 193
 194 static int nolock_plock(lm_lockspace_t *lockspace, struct lm_lockname *name,
 195                         struct file *file, int cmd, struct file_lock *fl)
 196 {
 197         int error;
 198         lock_kernel();
 199         error = posix_lock_file_wait(file, fl);
 200         unlock_kernel();
 201         return error;
 202 }
 203
 204 static int nolock_punlock(lm_lockspace_t *lockspace, struct lm_lockname *name,
 205                           struct file *file, struct file_lock *fl)
 206 {
 207         int error;
 208         lock_kernel();
 209         error = posix_lock_file_wait(file, fl);
 210         unlock_kernel();
 211         return error;
 212 }
 213
 214 static void nolock_recovery_done(lm_lockspace_t *lockspace, unsigned int jid,
 215                                  unsigned int message)
 216 {
 217 }
 218
 219 struct lm_lockops nolock_ops = {
 220         .lm_proto_name = "lock_nolock",
 221         .lm_mount = nolock_mount,
 222         .lm_others_may_mount = nolock_others_may_mount,
 223         .lm_unmount = nolock_unmount,
 224         .lm_withdraw = nolock_withdraw,
 225         .lm_get_lock = nolock_get_lock,
 226         .lm_put_lock = nolock_put_lock,
 227         .lm_lock = nolock_lock,
 228         .lm_unlock = nolock_unlock,
 229         .lm_cancel = nolock_cancel,
 230         .lm_hold_lvb = nolock_hold_lvb,
 231         .lm_unhold_lvb = nolock_unhold_lvb,
 232         .lm_sync_lvb = nolock_sync_lvb,
 233         .lm_plock_get = nolock_plock_get,
 234         .lm_plock = nolock_plock,
 235         .lm_punlock = nolock_punlock,
 236         .lm_recovery_done = nolock_recovery_done,
 237         .lm_owner = THIS_MODULE,
 238 };
 239
 240 int __init init_nolock(void)
 241 {
 242         int error;
 243
 244         error = gfs_register_lockproto(&nolock_ops);
 245         if (error) {
 246                 printk(KERN_WARNING "lock_nolock: can't register protocol: %d\n", error);
 247                 return error;
 248         }
 249
 250         printk(KERN_INFO "Lock_Nolock (built %s %s) installed\n", __DATE__, __TIME__);
 251         return 0;
 252 }
 253
 254 void __exit exit_nolock(void)
 255 {
 256         gfs_unregister_lockproto(&nolock_ops);
 257 }
 258
 259 module_init(init_nolock);
 260 module_exit(exit_nolock);
 261
 262 MODULE_DESCRIPTION("GFS Nolock Locking Module");
 263 MODULE_AUTHOR("Red Hat, Inc.");
 264 MODULE_LICENSE("GPL");
 265