fs/ocfs2/stackglue.c

   1 /* -*- mode: c; c-basic-offset: 8; -*-
   2  * vim: noexpandtab sw=8 ts=8 sts=0:
   3  *
   4  * stackglue.c
   5  *
   6  * Code which implements an OCFS2 specific interface to underlying
   7  * cluster stacks.
   8  *
   9  * Copyright (C) 2007 Oracle.  All rights reserved.
  10  *
  11  * This program is free software; you can redistribute it and/or
  12  * modify it under the terms of the GNU General Public
  13  * License as published by the Free Software Foundation, version 2.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  18  * General Public License for more details.
  19  */
  20
  21 #include "cluster/masklog.h"
  22 #include "stackglue.h"
  23
  24 static struct ocfs2_locking_protocol *lproto;
  25
  26 /* These should be identical */
  27 #if (DLM_LOCK_IV != LKM_IVMODE)
  28 # error Lock modes do not match
  29 #endif
  30 #if (DLM_LOCK_NL != LKM_NLMODE)
  31 # error Lock modes do not match
  32 #endif
  33 #if (DLM_LOCK_CR != LKM_CRMODE)
  34 # error Lock modes do not match
  35 #endif
  36 #if (DLM_LOCK_CW != LKM_CWMODE)
  37 # error Lock modes do not match
  38 #endif
  39 #if (DLM_LOCK_PR != LKM_PRMODE)
  40 # error Lock modes do not match
  41 #endif
  42 #if (DLM_LOCK_PW != LKM_PWMODE)
  43 # error Lock modes do not match
  44 #endif
  45 #if (DLM_LOCK_EX != LKM_EXMODE)
  46 # error Lock modes do not match
  47 #endif
  48 static inline int mode_to_o2dlm(int mode)
  49 {
  50         BUG_ON(mode > LKM_MAXMODE);
  51
  52         return mode;
  53 }
  54
  55 #define map_flag(_generic, _o2dlm)              \
  56         if (flags & (_generic)) {               \
  57                 flags &= ~(_generic);           \
  58                 o2dlm_flags |= (_o2dlm);        \
  59         }
  60 static int flags_to_o2dlm(u32 flags)
  61 {
  62         int o2dlm_flags = 0;
  63
  64         map_flag(DLM_LKF_NOQUEUE, LKM_NOQUEUE);
  65         map_flag(DLM_LKF_CANCEL, LKM_CANCEL);
  66         map_flag(DLM_LKF_CONVERT, LKM_CONVERT);
  67         map_flag(DLM_LKF_VALBLK, LKM_VALBLK);
  68         map_flag(DLM_LKF_IVVALBLK, LKM_INVVALBLK);
  69         map_flag(DLM_LKF_ORPHAN, LKM_ORPHAN);
  70         map_flag(DLM_LKF_FORCEUNLOCK, LKM_FORCE);
  71         map_flag(DLM_LKF_TIMEOUT, LKM_TIMEOUT);
  72         map_flag(DLM_LKF_LOCAL, LKM_LOCAL);
  73
  74         /* map_flag() should have cleared every flag passed in */
  75         BUG_ON(flags != 0);
  76
  77         return o2dlm_flags;
  78 }
  79 #undef map_flag
  80
  81 /*
  82  * Map an o2dlm status to standard errno values.
  83  *
  84  * o2dlm only uses a handful of these, and returns even fewer to the
  85  * caller. Still, we try to assign sane values to each error.
  86  *
  87  * The following value pairs have special meanings to dlmglue, thus
  88  * the right hand side needs to stay unique - never duplicate the
  89  * mapping elsewhere in the table!
  90  *
  91  * DLM_NORMAL:          0
  92  * DLM_NOTQUEUED:       -EAGAIN
  93  * DLM_CANCELGRANT:     -DLM_ECANCEL
  94  * DLM_CANCEL:          -DLM_EUNLOCK
  95  */
  96 /* Keep in sync with dlmapi.h */
  97 static int status_map[] = {
  98         [DLM_NORMAL]                    = 0,            /* Success */
  99         [DLM_GRANTED]                   = -EINVAL,
 100         [DLM_DENIED]                    = -EACCES,
 101         [DLM_DENIED_NOLOCKS]            = -EACCES,
 102         [DLM_WORKING]                   = -EBUSY,
 103         [DLM_BLOCKED]                   = -EINVAL,
 104         [DLM_BLOCKED_ORPHAN]            = -EINVAL,
 105         [DLM_DENIED_GRACE_PERIOD]       = -EACCES,
 106         [DLM_SYSERR]                    = -ENOMEM,      /* It is what it is */
 107         [DLM_NOSUPPORT]                 = -EPROTO,
 108         [DLM_CANCELGRANT]               = -DLM_ECANCEL, /* Cancel after grant */
 109         [DLM_IVLOCKID]                  = -EINVAL,
 110         [DLM_SYNC]                      = -EINVAL,
 111         [DLM_BADTYPE]                   = -EINVAL,
 112         [DLM_BADRESOURCE]               = -EINVAL,
 113         [DLM_MAXHANDLES]                = -ENOMEM,
 114         [DLM_NOCLINFO]                  = -EINVAL,
 115         [DLM_NOLOCKMGR]                 = -EINVAL,
 116         [DLM_NOPURGED]                  = -EINVAL,
 117         [DLM_BADARGS]                   = -EINVAL,
 118         [DLM_VOID]                      = -EINVAL,
 119         [DLM_NOTQUEUED]                 = -EAGAIN,      /* Trylock failed */
 120         [DLM_IVBUFLEN]                  = -EINVAL,
 121         [DLM_CVTUNGRANT]                = -EPERM,
 122         [DLM_BADPARAM]                  = -EINVAL,
 123         [DLM_VALNOTVALID]               = -EINVAL,
 124         [DLM_REJECTED]                  = -EPERM,
 125         [DLM_ABORT]                     = -EINVAL,
 126         [DLM_CANCEL]                    = -DLM_EUNLOCK, /* Successful cancel */
 127         [DLM_IVRESHANDLE]               = -EINVAL,
 128         [DLM_DEADLOCK]                  = -EDEADLK,
 129         [DLM_DENIED_NOASTS]             = -EINVAL,
 130         [DLM_FORWARD]                   = -EINVAL,
 131         [DLM_TIMEOUT]                   = -ETIMEDOUT,
 132         [DLM_IVGROUPID]                 = -EINVAL,
 133         [DLM_VERS_CONFLICT]             = -EOPNOTSUPP,
 134         [DLM_BAD_DEVICE_PATH]           = -ENOENT,
 135         [DLM_NO_DEVICE_PERMISSION]      = -EPERM,
 136         [DLM_NO_CONTROL_DEVICE]         = -ENOENT,
 137         [DLM_RECOVERING]                = -ENOTCONN,
 138         [DLM_MIGRATING]                 = -ERESTART,
 139         [DLM_MAXSTATS]                  = -EINVAL,
 140 };
 141 static int dlm_status_to_errno(enum dlm_status status)
 142 {
 143         BUG_ON(status > (sizeof(status_map) / sizeof(status_map[0])));
 144
 145         return status_map[status];
 146 }
 147
 148 static void o2dlm_lock_ast_wrapper(void *astarg)
 149 {
 150         BUG_ON(lproto == NULL);
 151
 152         lproto->lp_lock_ast(astarg);
 153 }
 154
 155 static void o2dlm_blocking_ast_wrapper(void *astarg, int level)
 156 {
 157         BUG_ON(lproto == NULL);
 158
 159         lproto->lp_blocking_ast(astarg, level);
 160 }
 161
 162 static void o2dlm_unlock_ast_wrapper(void *astarg, enum dlm_status status)
 163 {
 164         int error;
 165
 166         BUG_ON(lproto == NULL);
 167
 168         /*
 169          * XXX: CANCEL values are sketchy.
 170          *
 171          * Currently we have preserved the o2dlm paradigm.  You can get
 172          * unlock_ast() whether the cancel succeded or not.
 173          *
 174          * First, we're going to pass DLM_EUNLOCK just like fs/dlm does for
 175          * successful unlocks.  That is a clean behavior.
 176          *
 177          * In o2dlm, you can get both the lock_ast() for the lock being
 178          * granted and the unlock_ast() for the CANCEL failing.  A
 179          * successful cancel sends DLM_NORMAL here.  If the
 180          * lock grant happened before the cancel arrived, you get
 181          * DLM_CANCELGRANT.  For now, we'll use DLM_ECANCEL to signify
 182          * CANCELGRANT - the CANCEL was supposed to happen but didn't.  We
 183          * can then use DLM_EUNLOCK to signify a successful CANCEL -
 184          * effectively, the CANCEL caused the lock to roll back.
 185          *
 186          * In the future, we will likely move the o2dlm to send only one
 187          * ast - either unlock_ast() for a successful CANCEL or lock_ast()
 188          * when the grant succeeds.  At that point, we'll send DLM_ECANCEL
 189          * for all cancel results (CANCELGRANT will no longer exist).
 190          */
 191         error = dlm_status_to_errno(status);
 192
 193         /* Successful unlock is DLM_EUNLOCK */
 194         if (!error)
 195                 error = -DLM_EUNLOCK;
 196
 197         lproto->lp_unlock_ast(astarg, error);
 198 }
 199
 200 int ocfs2_dlm_lock(struct dlm_ctxt *dlm,
 201                    int mode,
 202                    union ocfs2_dlm_lksb *lksb,
 203                    u32 flags,
 204                    void *name,
 205                    unsigned int namelen,
 206                    void *astarg)
 207 {
 208         enum dlm_status status;
 209         int o2dlm_mode = mode_to_o2dlm(mode);
 210         int o2dlm_flags = flags_to_o2dlm(flags);
 211         int ret;
 212
 213         BUG_ON(lproto == NULL);
 214
 215         status = dlmlock(dlm, o2dlm_mode, &lksb->lksb_o2dlm, o2dlm_flags,
 216                          name, namelen,
 217                          o2dlm_lock_ast_wrapper, astarg,
 218                          o2dlm_blocking_ast_wrapper);
 219         ret = dlm_status_to_errno(status);
 220         return ret;
 221 }
 222
 223 int ocfs2_dlm_unlock(struct dlm_ctxt *dlm,
 224                      union ocfs2_dlm_lksb *lksb,
 225                      u32 flags,
 226                      void *astarg)
 227 {
 228         enum dlm_status status;
 229         int o2dlm_flags = flags_to_o2dlm(flags);
 230         int ret;
 231
 232         BUG_ON(lproto == NULL);
 233
 234         status = dlmunlock(dlm, &lksb->lksb_o2dlm, o2dlm_flags,
 235                            o2dlm_unlock_ast_wrapper, astarg);
 236         ret = dlm_status_to_errno(status);
 237         return ret;
 238 }
 239
 240 int ocfs2_dlm_lock_status(union ocfs2_dlm_lksb *lksb)
 241 {
 242         return dlm_status_to_errno(lksb->lksb_o2dlm.status);
 243 }
 244
 245 /*
 246  * Why don't we cast to ocfs2_meta_lvb?  The "clean" answer is that we
 247  * don't cast at the glue level.  The real answer is that the header
 248  * ordering is nigh impossible.
 249  */
 250 void *ocfs2_dlm_lvb(union ocfs2_dlm_lksb *lksb)
 251 {
 252         return (void *)(lksb->lksb_o2dlm.lvb);
 253 }
 254
 255 void o2cb_get_stack(struct ocfs2_locking_protocol *proto)
 256 {
 257         BUG_ON(proto == NULL);
 258
 259         lproto = proto;
 260 }
 261
 262 void o2cb_put_stack(void)
 263 {
 264         lproto = NULL;
 265 }