release/src-rt-6.x.4708/linux/linux-2.6.36/fs/gfs2/lock_dlm.c

   1 /*
   2  * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
   3  * Copyright (C) 2004-2009 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 #include <linux/fs.h>
  11 #include <linux/dlm.h>
  12 #include <linux/slab.h>
  13 #include <linux/types.h>
  14 #include <linux/gfs2_ondisk.h>
  15
  16 #include "incore.h"
  17 #include "glock.h"
  18 #include "util.h"
  19
  20
  21 static void gdlm_ast(void *arg)
  22 {
  23         struct gfs2_glock *gl = arg;
  24         unsigned ret = gl->gl_state;
  25         struct gfs2_sbd *sdp = gl->gl_sbd;
  26
  27         BUG_ON(gl->gl_lksb.sb_flags & DLM_SBF_DEMOTED);
  28
  29         if (gl->gl_lksb.sb_flags & DLM_SBF_VALNOTVALID)
  30                 memset(gl->gl_lvb, 0, GDLM_LVB_SIZE);
  31
  32         switch (gl->gl_lksb.sb_status) {
  33         case -DLM_EUNLOCK: /* Unlocked, so glock can be freed */
  34                 if (gl->gl_ops->go_flags & GLOF_ASPACE)
  35                         kmem_cache_free(gfs2_glock_aspace_cachep, gl);
  36                 else
  37                         kmem_cache_free(gfs2_glock_cachep, gl);
  38                 if (atomic_dec_and_test(&sdp->sd_glock_disposal))
  39                         wake_up(&sdp->sd_glock_wait);
  40                 return;
  41         case -DLM_ECANCEL: /* Cancel while getting lock */
  42                 ret |= LM_OUT_CANCELED;
  43                 goto out;
  44         case -EAGAIN: /* Try lock fails */
  45                 goto out;
  46         case -EINVAL: /* Invalid */
  47         case -ENOMEM: /* Out of memory */
  48                 ret |= LM_OUT_ERROR;
  49                 goto out;
  50         case 0: /* Success */
  51                 break;
  52         default: /* Something unexpected */
  53                 BUG();
  54         }
  55
  56         ret = gl->gl_req;
  57         if (gl->gl_lksb.sb_flags & DLM_SBF_ALTMODE) {
  58                 if (gl->gl_req == LM_ST_SHARED)
  59                         ret = LM_ST_DEFERRED;
  60                 else if (gl->gl_req == LM_ST_DEFERRED)
  61                         ret = LM_ST_SHARED;
  62                 else
  63                         BUG();
  64         }
  65
  66         set_bit(GLF_INITIAL, &gl->gl_flags);
  67         gfs2_glock_complete(gl, ret);
  68         return;
  69 out:
  70         if (!test_bit(GLF_INITIAL, &gl->gl_flags))
  71                 gl->gl_lksb.sb_lkid = 0;
  72         gfs2_glock_complete(gl, ret);
  73 }
  74
  75 static void gdlm_bast(void *arg, int mode)
  76 {
  77         struct gfs2_glock *gl = arg;
  78
  79         switch (mode) {
  80         case DLM_LOCK_EX:
  81                 gfs2_glock_cb(gl, LM_ST_UNLOCKED);
  82                 break;
  83         case DLM_LOCK_CW:
  84                 gfs2_glock_cb(gl, LM_ST_DEFERRED);
  85                 break;
  86         case DLM_LOCK_PR:
  87                 gfs2_glock_cb(gl, LM_ST_SHARED);
  88                 break;
  89         default:
  90                 printk(KERN_ERR "unknown bast mode %d", mode);
  91                 BUG();
  92         }
  93 }
  94
  95 /* convert gfs lock-state to dlm lock-mode */
  96
  97 static int make_mode(const unsigned int lmstate)
  98 {
  99         switch (lmstate) {
 100         case LM_ST_UNLOCKED:
 101                 return DLM_LOCK_NL;
 102         case LM_ST_EXCLUSIVE:
 103                 return DLM_LOCK_EX;
 104         case LM_ST_DEFERRED:
 105                 return DLM_LOCK_CW;
 106         case LM_ST_SHARED:
 107                 return DLM_LOCK_PR;
 108         }
 109         printk(KERN_ERR "unknown LM state %d", lmstate);
 110         BUG();
 111         return -1;
 112 }
 113
 114 static u32 make_flags(const u32 lkid, const unsigned int gfs_flags,
 115                       const int req)
 116 {
 117         u32 lkf = 0;
 118
 119         if (gfs_flags & LM_FLAG_TRY)
 120                 lkf |= DLM_LKF_NOQUEUE;
 121
 122         if (gfs_flags & LM_FLAG_TRY_1CB) {
 123                 lkf |= DLM_LKF_NOQUEUE;
 124                 lkf |= DLM_LKF_NOQUEUEBAST;
 125         }
 126
 127         if (gfs_flags & LM_FLAG_PRIORITY) {
 128                 lkf |= DLM_LKF_NOORDER;
 129                 lkf |= DLM_LKF_HEADQUE;
 130         }
 131
 132         if (gfs_flags & LM_FLAG_ANY) {
 133                 if (req == DLM_LOCK_PR)
 134                         lkf |= DLM_LKF_ALTCW;
 135                 else if (req == DLM_LOCK_CW)
 136                         lkf |= DLM_LKF_ALTPR;
 137                 else
 138                         BUG();
 139         }
 140
 141         if (lkid != 0)
 142                 lkf |= DLM_LKF_CONVERT;
 143
 144         lkf |= DLM_LKF_VALBLK;
 145
 146         return lkf;
 147 }
 148
 149 static unsigned int gdlm_lock(struct gfs2_glock *gl,
 150                               unsigned int req_state, unsigned int flags)
 151 {
 152         struct lm_lockstruct *ls = &gl->gl_sbd->sd_lockstruct;
 153         int error;
 154         int req;
 155         u32 lkf;
 156
 157         gl->gl_req = req_state;
 158         req = make_mode(req_state);
 159         lkf = make_flags(gl->gl_lksb.sb_lkid, flags, req);
 160
 161         /*
 162          * Submit the actual lock request.
 163          */
 164
 165         error = dlm_lock(ls->ls_dlm, req, &gl->gl_lksb, lkf, gl->gl_strname,
 166                          GDLM_STRNAME_BYTES - 1, 0, gdlm_ast, gl, gdlm_bast);
 167         if (error == -EAGAIN)
 168                 return 0;
 169         if (error)
 170                 return LM_OUT_ERROR;
 171         return LM_OUT_ASYNC;
 172 }
 173
 174 static void gdlm_put_lock(struct kmem_cache *cachep, struct gfs2_glock *gl)
 175 {
 176         struct gfs2_sbd *sdp = gl->gl_sbd;
 177         struct lm_lockstruct *ls = &sdp->sd_lockstruct;
 178         int error;
 179
 180         if (gl->gl_lksb.sb_lkid == 0) {
 181                 kmem_cache_free(cachep, gl);
 182                 if (atomic_dec_and_test(&sdp->sd_glock_disposal))
 183                         wake_up(&sdp->sd_glock_wait);
 184                 return;
 185         }
 186
 187         error = dlm_unlock(ls->ls_dlm, gl->gl_lksb.sb_lkid, DLM_LKF_VALBLK,
 188                            NULL, gl);
 189         if (error) {
 190                 printk(KERN_ERR "gdlm_unlock %x,%llx err=%d\n",
 191                        gl->gl_name.ln_type,
 192                        (unsigned long long)gl->gl_name.ln_number, error);
 193                 return;
 194         }
 195 }
 196
 197 static void gdlm_cancel(struct gfs2_glock *gl)
 198 {
 199         struct lm_lockstruct *ls = &gl->gl_sbd->sd_lockstruct;
 200         dlm_unlock(ls->ls_dlm, gl->gl_lksb.sb_lkid, DLM_LKF_CANCEL, NULL, gl);
 201 }
 202
 203 static int gdlm_mount(struct gfs2_sbd *sdp, const char *fsname)
 204 {
 205         struct lm_lockstruct *ls = &sdp->sd_lockstruct;
 206         int error;
 207
 208         if (fsname == NULL) {
 209                 fs_info(sdp, "no fsname found\n");
 210                 return -EINVAL;
 211         }
 212
 213         error = dlm_new_lockspace(fsname, strlen(fsname), &ls->ls_dlm,
 214                                   DLM_LSFL_FS | DLM_LSFL_NEWEXCL |
 215                                   (ls->ls_nodir ? DLM_LSFL_NODIR : 0),
 216                                   GDLM_LVB_SIZE);
 217         if (error)
 218                 printk(KERN_ERR "dlm_new_lockspace error %d", error);
 219
 220         return error;
 221 }
 222
 223 static void gdlm_unmount(struct gfs2_sbd *sdp)
 224 {
 225         struct lm_lockstruct *ls = &sdp->sd_lockstruct;
 226
 227         if (ls->ls_dlm) {
 228                 dlm_release_lockspace(ls->ls_dlm, 2);
 229                 ls->ls_dlm = NULL;
 230         }
 231 }
 232
 233 static const match_table_t dlm_tokens = {
 234         { Opt_jid, "jid=%d"},
 235         { Opt_id, "id=%d"},
 236         { Opt_first, "first=%d"},
 237         { Opt_nodir, "nodir=%d"},
 238         { Opt_err, NULL },
 239 };
 240
 241 const struct lm_lockops gfs2_dlm_ops = {
 242         .lm_proto_name = "lock_dlm",
 243         .lm_mount = gdlm_mount,
 244         .lm_unmount = gdlm_unmount,
 245         .lm_put_lock = gdlm_put_lock,
 246         .lm_lock = gdlm_lock,
 247         .lm_cancel = gdlm_cancel,
 248         .lm_tokens = &dlm_tokens,
 249 };