SAFE public projects git trees. - safe/jmp/linux-2.6/blob - 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/types.h>
  13 #include <linux/gfs2_ondisk.h>
  14
  15 #include "incore.h"
  16 #include "glock.h"
  17 #include "util.h"
  18
  19
  20 static void gdlm_ast(void *arg)
  21 {
  22         struct gfs2_glock *gl = arg;
  23         unsigned ret = gl->gl_state;
  24         struct gfs2_sbd *sdp = gl->gl_sbd;
  25
  26         BUG_ON(gl->gl_lksb.sb_flags & DLM_SBF_DEMOTED);
  27
  28         if (gl->gl_lksb.sb_flags & DLM_SBF_VALNOTVALID)
  29                 memset(gl->gl_lvb, 0, GDLM_LVB_SIZE);
  30
  31         switch (gl->gl_lksb.sb_status) {
  32         case -DLM_EUNLOCK: /* Unlocked, so glock can be freed */
  33                 kmem_cache_free(gfs2_glock_cachep, gl);
  34                 if (atomic_dec_and_test(&sdp->sd_glock_disposal))
  35                         wake_up(&sdp->sd_glock_wait);
  36                 return;
  37         case -DLM_ECANCEL: /* Cancel while getting lock */
  38                 ret |= LM_OUT_CANCELED;
  39                 goto out;
  40         case -EAGAIN: /* Try lock fails */
  41                 goto out;
  42         case -EINVAL: /* Invalid */
  43         case -ENOMEM: /* Out of memory */
  44                 ret |= LM_OUT_ERROR;
  45                 goto out;
  46         case 0: /* Success */
  47                 break;
  48         default: /* Something unexpected */
  49                 BUG();
  50         }
  51
  52         ret = gl->gl_req;
  53         if (gl->gl_lksb.sb_flags & DLM_SBF_ALTMODE) {
  54                 if (gl->gl_req == LM_ST_SHARED)
  55                         ret = LM_ST_DEFERRED;
  56                 else if (gl->gl_req == LM_ST_DEFERRED)
  57                         ret = LM_ST_SHARED;
  58                 else
  59                         BUG();
  60         }
  61
  62         set_bit(GLF_INITIAL, &gl->gl_flags);
  63         gfs2_glock_complete(gl, ret);
  64         return;
  65 out:
  66         if (!test_bit(GLF_INITIAL, &gl->gl_flags))
  67                 gl->gl_lksb.sb_lkid = 0;
  68         gfs2_glock_complete(gl, ret);
  69 }
  70
  71 static void gdlm_bast(void *arg, int mode)
  72 {
  73         struct gfs2_glock *gl = arg;
  74
  75         switch (mode) {
  76         case DLM_LOCK_EX:
  77                 gfs2_glock_cb(gl, LM_ST_UNLOCKED);
  78                 break;
  79         case DLM_LOCK_CW:
  80                 gfs2_glock_cb(gl, LM_ST_DEFERRED);
  81                 break;
  82         case DLM_LOCK_PR:
  83                 gfs2_glock_cb(gl, LM_ST_SHARED);
  84                 break;
  85         default:
  86                 printk(KERN_ERR "unknown bast mode %d", mode);
  87                 BUG();
  88         }
  89 }
  90
  91 /* convert gfs lock-state to dlm lock-mode */
  92
  93 static int make_mode(const unsigned int lmstate)
  94 {
  95         switch (lmstate) {
  96         case LM_ST_UNLOCKED:
  97                 return DLM_LOCK_NL;
  98         case LM_ST_EXCLUSIVE:
  99                 return DLM_LOCK_EX;
 100         case LM_ST_DEFERRED:
 101                 return DLM_LOCK_CW;
 102         case LM_ST_SHARED:
 103                 return DLM_LOCK_PR;
 104         }
 105         printk(KERN_ERR "unknown LM state %d", lmstate);
 106         BUG();
 107         return -1;
 108 }
 109
 110 static u32 make_flags(const u32 lkid, const unsigned int gfs_flags,
 111                       const int req)
 112 {
 113         u32 lkf = 0;
 114
 115         if (gfs_flags & LM_FLAG_TRY)
 116                 lkf |= DLM_LKF_NOQUEUE;
 117
 118         if (gfs_flags & LM_FLAG_TRY_1CB) {
 119                 lkf |= DLM_LKF_NOQUEUE;
 120                 lkf |= DLM_LKF_NOQUEUEBAST;
 121         }
 122
 123         if (gfs_flags & LM_FLAG_PRIORITY) {
 124                 lkf |= DLM_LKF_NOORDER;
 125                 lkf |= DLM_LKF_HEADQUE;
 126         }
 127
 128         if (gfs_flags & LM_FLAG_ANY) {
 129                 if (req == DLM_LOCK_PR)
 130                         lkf |= DLM_LKF_ALTCW;
 131                 else if (req == DLM_LOCK_CW)
 132                         lkf |= DLM_LKF_ALTPR;
 133                 else
 134                         BUG();
 135         }
 136
 137         if (lkid != 0)
 138                 lkf |= DLM_LKF_CONVERT;
 139
 140         lkf |= DLM_LKF_VALBLK;
 141
 142         return lkf;
 143 }
 144
 145 static unsigned int gdlm_lock(struct gfs2_glock *gl,
 146                               unsigned int req_state, unsigned int flags)
 147 {
 148         struct lm_lockstruct *ls = &gl->gl_sbd->sd_lockstruct;
 149         int error;
 150         int req;
 151         u32 lkf;
 152
 153         gl->gl_req = req_state;
 154         req = make_mode(req_state);
 155         lkf = make_flags(gl->gl_lksb.sb_lkid, flags, req);
 156
 157         /*
 158          * Submit the actual lock request.
 159          */
 160
 161         error = dlm_lock(ls->ls_dlm, req, &gl->gl_lksb, lkf, gl->gl_strname,
 162                          GDLM_STRNAME_BYTES - 1, 0, gdlm_ast, gl, gdlm_bast);
 163         if (error == -EAGAIN)
 164                 return 0;
 165         if (error)
 166                 return LM_OUT_ERROR;
 167         return LM_OUT_ASYNC;
 168 }
 169
 170 static void gdlm_put_lock(struct kmem_cache *cachep, struct gfs2_glock *gl)
 171 {
 172         struct gfs2_sbd *sdp = gl->gl_sbd;
 173         struct lm_lockstruct *ls = &sdp->sd_lockstruct;
 174         int error;
 175
 176         if (gl->gl_lksb.sb_lkid == 0) {
 177                 kmem_cache_free(cachep, gl);
 178                 if (atomic_dec_and_test(&sdp->sd_glock_disposal))
 179                         wake_up(&sdp->sd_glock_wait);
 180                 return;
 181         }
 182
 183         error = dlm_unlock(ls->ls_dlm, gl->gl_lksb.sb_lkid, DLM_LKF_VALBLK,
 184                            NULL, gl);
 185         if (error) {
 186                 printk(KERN_ERR "gdlm_unlock %x,%llx err=%d\n",
 187                        gl->gl_name.ln_type,
 188                        (unsigned long long)gl->gl_name.ln_number, error);
 189                 return;
 190         }
 191 }
 192
 193 static void gdlm_cancel(struct gfs2_glock *gl)
 194 {
 195         struct lm_lockstruct *ls = &gl->gl_sbd->sd_lockstruct;
 196         dlm_unlock(ls->ls_dlm, gl->gl_lksb.sb_lkid, DLM_LKF_CANCEL, NULL, gl);
 197 }
 198
 199 static int gdlm_mount(struct gfs2_sbd *sdp, const char *fsname)
 200 {
 201         struct lm_lockstruct *ls = &sdp->sd_lockstruct;
 202         int error;
 203
 204         if (fsname == NULL) {
 205                 fs_info(sdp, "no fsname found\n");
 206                 return -EINVAL;
 207         }
 208
 209         error = dlm_new_lockspace(fsname, strlen(fsname), &ls->ls_dlm,
 210                                   DLM_LSFL_FS | DLM_LSFL_NEWEXCL |
 211                                   (ls->ls_nodir ? DLM_LSFL_NODIR : 0),
 212                                   GDLM_LVB_SIZE);
 213         if (error)
 214                 printk(KERN_ERR "dlm_new_lockspace error %d", error);
 215
 216         return error;
 217 }
 218
 219 static void gdlm_unmount(struct gfs2_sbd *sdp)
 220 {
 221         struct lm_lockstruct *ls = &sdp->sd_lockstruct;
 222
 223         if (ls->ls_dlm) {
 224                 dlm_release_lockspace(ls->ls_dlm, 2);
 225                 ls->ls_dlm = NULL;
 226         }
 227 }
 228
 229 static const match_table_t dlm_tokens = {
 230         { Opt_jid, "jid=%d"},
 231         { Opt_id, "id=%d"},
 232         { Opt_first, "first=%d"},
 233         { Opt_nodir, "nodir=%d"},
 234         { Opt_err, NULL },
 235 };
 236
 237 const struct lm_lockops gfs2_dlm_ops = {
 238         .lm_proto_name = "lock_dlm",
 239         .lm_mount = gdlm_mount,
 240         .lm_unmount = gdlm_unmount,
 241         .lm_put_lock = gdlm_put_lock,
 242         .lm_lock = gdlm_lock,
 243         .lm_cancel = gdlm_cancel,
 244         .lm_tokens = &dlm_tokens,
 245 };
 246