drivers/staging/lustre/lustre/include/lustre_mdc.h

   1 /*
   2  * GPL HEADER START
   3  *
   4  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 only,
   8  * as published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful, but
  11  * WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * General Public License version 2 for more details (a copy is included
  14  * in the LICENSE file that accompanied this code).
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * version 2 along with this program; If not, see
  18  * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf
  19  *
  20  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
  21  * CA 95054 USA or visit www.sun.com if you need additional information or
  22  * have any questions.
  23  *
  24  * GPL HEADER END
  25  */
  26 /*
  27  * Copyright (c) 2007, 2010, Oracle and/or its affiliates. All rights reserved.
  28  * Use is subject to license terms.
  29  */
  30 /*
  31  * Copyright (c) 2011, 2012, Intel Corporation.
  32  */
  33 /*
  34  * This file is part of Lustre, http://www.lustre.org/
  35  * Lustre is a trademark of Sun Microsystems, Inc.
  36  *
  37  * lustre/include/lustre_mdc.h
  38  *
  39  * MDS data structures.
  40  * See also lustre_idl.h for wire formats of requests.
  41  */
  42
  43 #ifndef _LUSTRE_MDC_H
  44 #define _LUSTRE_MDC_H
  45
  46 /** \defgroup mdc mdc
  47  *
  48  * @{
  49  */
  50
  51 #include <linux/fs.h>
  52 #include <linux/dcache.h>
  53 #include "lustre_intent.h"
  54 #include "lustre_handles.h"
  55 #include "../../include/linux/libcfs/libcfs.h"
  56 #include "obd_class.h"
  57 #include "lustre/lustre_idl.h"
  58 #include "lustre_lib.h"
  59 #include "lustre_dlm.h"
  60 #include "lustre_export.h"
  61
  62 struct ptlrpc_client;
  63 struct obd_export;
  64 struct ptlrpc_request;
  65 struct obd_device;
  66
  67 struct mdc_rpc_lock {
  68         struct mutex            rpcl_mutex;
  69         struct lookup_intent    *rpcl_it;
  70         int                     rpcl_fakes;
  71 };
  72
  73 #define MDC_FAKE_RPCL_IT ((void *)0x2c0012bfUL)
  74
  75 static inline void mdc_init_rpc_lock(struct mdc_rpc_lock *lck)
  76 {
  77         mutex_init(&lck->rpcl_mutex);
  78         lck->rpcl_it = NULL;
  79 }
  80
  81 static inline void mdc_get_rpc_lock(struct mdc_rpc_lock *lck,
  82                                     struct lookup_intent *it)
  83 {
  84         if (it && (it->it_op == IT_GETATTR || it->it_op == IT_LOOKUP ||
  85                    it->it_op == IT_LAYOUT))
  86                 return;
  87
  88         /* This would normally block until the existing request finishes.
  89          * If fail_loc is set it will block until the regular request is
  90          * done, then set rpcl_it to MDC_FAKE_RPCL_IT.  Once that is set
  91          * it will only be cleared when all fake requests are finished.
  92          * Only when all fake requests are finished can normal requests
  93          * be sent, to ensure they are recoverable again.
  94          */
  95  again:
  96         mutex_lock(&lck->rpcl_mutex);
  97
  98         if (CFS_FAIL_CHECK_QUIET(OBD_FAIL_MDC_RPCS_SEM)) {
  99                 lck->rpcl_it = MDC_FAKE_RPCL_IT;
 100                 lck->rpcl_fakes++;
 101                 mutex_unlock(&lck->rpcl_mutex);
 102                 return;
 103         }
 104
 105         /* This will only happen when the CFS_FAIL_CHECK() was
 106          * just turned off but there are still requests in progress.
 107          * Wait until they finish.  It doesn't need to be efficient
 108          * in this extremely rare case, just have low overhead in
 109          * the common case when it isn't true.
 110          */
 111         while (unlikely(lck->rpcl_it == MDC_FAKE_RPCL_IT)) {
 112                 mutex_unlock(&lck->rpcl_mutex);
 113                 schedule_timeout(cfs_time_seconds(1) / 4);
 114                 goto again;
 115         }
 116
 117         LASSERT(!lck->rpcl_it);
 118         lck->rpcl_it = it;
 119 }
 120
 121 static inline void mdc_put_rpc_lock(struct mdc_rpc_lock *lck,
 122                                     struct lookup_intent *it)
 123 {
 124         if (it && (it->it_op == IT_GETATTR || it->it_op == IT_LOOKUP ||
 125                    it->it_op == IT_LAYOUT))
 126                 return;
 127
 128         if (lck->rpcl_it == MDC_FAKE_RPCL_IT) { /* OBD_FAIL_MDC_RPCS_SEM */
 129                 mutex_lock(&lck->rpcl_mutex);
 130
 131                 LASSERTF(lck->rpcl_fakes > 0, "%d\n", lck->rpcl_fakes);
 132                 lck->rpcl_fakes--;
 133
 134                 if (lck->rpcl_fakes == 0)
 135                         lck->rpcl_it = NULL;
 136
 137         } else {
 138                 LASSERTF(it == lck->rpcl_it, "%p != %p\n", it, lck->rpcl_it);
 139                 lck->rpcl_it = NULL;
 140         }
 141
 142         mutex_unlock(&lck->rpcl_mutex);
 143 }
 144
 145 /* Update the maximum observed easize and cookiesize.  The default easize
 146  * and cookiesize is initialized to the minimum value but allowed to grow
 147  * up to a single page in size if required to handle the common case.
 148  */
 149 static inline void mdc_update_max_ea_from_body(struct obd_export *exp,
 150                                                struct mdt_body *body)
 151 {
 152         if (body->valid & OBD_MD_FLMODEASIZE) {
 153                 struct client_obd *cli = &exp->exp_obd->u.cli;
 154
 155                 if (cli->cl_max_mds_easize < body->max_mdsize) {
 156                         cli->cl_max_mds_easize = body->max_mdsize;
 157                         cli->cl_default_mds_easize =
 158                             min_t(__u32, body->max_mdsize, PAGE_CACHE_SIZE);
 159                 }
 160                 if (cli->cl_max_mds_cookiesize < body->max_cookiesize) {
 161                         cli->cl_max_mds_cookiesize = body->max_cookiesize;
 162                         cli->cl_default_mds_cookiesize =
 163                             min_t(__u32, body->max_cookiesize, PAGE_CACHE_SIZE);
 164                 }
 165         }
 166 }
 167
 168 struct mdc_cache_waiter {
 169         struct list_head              mcw_entry;
 170         wait_queue_head_t            mcw_waitq;
 171 };
 172
 173 /* mdc/mdc_locks.c */
 174 int it_disposition(struct lookup_intent *it, int flag);
 175 void it_clear_disposition(struct lookup_intent *it, int flag);
 176 void it_set_disposition(struct lookup_intent *it, int flag);
 177 int it_open_error(int phase, struct lookup_intent *it);
 178
 179 static inline bool cl_is_lov_delay_create(unsigned int flags)
 180 {
 181         return (flags & O_LOV_DELAY_CREATE) == O_LOV_DELAY_CREATE;
 182 }
 183
 184 static inline void cl_lov_delay_create_clear(unsigned int *flags)
 185 {
 186         if ((*flags & O_LOV_DELAY_CREATE) == O_LOV_DELAY_CREATE)
 187                 *flags &= ~O_LOV_DELAY_CREATE;
 188 }
 189
 190 /** @} mdc */
 191
 192 #endif