lustre/lov/lov_lock.c

   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) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
  28  * Use is subject to license terms.
  29  *
  30  * Copyright (c) 2011, 2014, Intel Corporation.
  31  */
  32 /*
  33  * This file is part of Lustre, http://www.lustre.org/
  34  * Lustre is a trademark of Sun Microsystems, Inc.
  35  *
  36  * Implementation of cl_lock for LOV layer.
  37  *
  38  *   Author: Nikita Danilov <nikita.danilov@sun.com>
  39  */
  40
  41 #define DEBUG_SUBSYSTEM S_LOV
  42
  43 #include "lov_cl_internal.h"
  44
  45 /** \addtogroup lov
  46  *  @{
  47  */
  48
  49 /*****************************************************************************
  50  *
  51  * Lov lock operations.
  52  *
  53  */
  54
  55 static struct lov_sublock_env *lov_sublock_env_get(const struct lu_env *env,
  56                                                    const struct cl_lock *parent,
  57                                                    struct lov_lock_sub *lls)
  58 {
  59         struct lov_sublock_env *subenv;
  60         struct lov_io          *lio    = lov_env_io(env);
  61         struct cl_io           *io     = lio->lis_cl.cis_io;
  62         struct lov_io_sub      *sub;
  63
  64         subenv = &lov_env_session(env)->ls_subenv;
  65
  66         /*
  67          * FIXME: We tend to use the subio's env & io to call the sublock
  68          * lock operations because osc lock sometimes stores some control
  69          * variables in thread's IO infomation(Now only lockless information).
  70          * However, if the lock's host(object) is different from the object
  71          * for current IO, we have no way to get the subenv and subio because
  72          * they are not initialized at all. As a temp fix, in this case,
  73          * we still borrow the parent's env to call sublock operations.
  74          */
  75         if (!io || !cl_object_same(io->ci_obj, parent->cll_descr.cld_obj)) {
  76                 subenv->lse_env = env;
  77                 subenv->lse_io = io;
  78         } else {
  79                 sub = lov_sub_get(env, lio, lls->sub_stripe);
  80                 if (!IS_ERR(sub)) {
  81                         subenv->lse_env = sub->sub_env;
  82                         subenv->lse_io  = sub->sub_io;
  83                 } else {
  84                         subenv = (void*)sub;
  85                 }
  86         }
  87         return subenv;
  88 }
  89
  90 static int lov_sublock_init(const struct lu_env *env,
  91                             const struct cl_lock *parent,
  92                             struct lov_lock_sub *lls)
  93 {
  94         struct lov_sublock_env *subenv;
  95         int result;
  96         ENTRY;
  97
  98         subenv = lov_sublock_env_get(env, parent, lls);
  99         if (!IS_ERR(subenv)) {
 100                 result = cl_lock_init(subenv->lse_env, &lls->sub_lock,
 101                                       subenv->lse_io);
 102         } else {
 103                 /* error occurs. */
 104                 result = PTR_ERR(subenv);
 105         }
 106         RETURN(result);
 107 }
 108
 109 /**
 110  * Creates sub-locks for a given lov_lock for the first time.
 111  *
 112  * Goes through all sub-objects of top-object, and creates sub-locks on every
 113  * sub-object intersecting with top-lock extent. This is complicated by the
 114  * fact that top-lock (that is being created) can be accessed concurrently
 115  * through already created sub-locks (possibly shared with other top-locks).
 116  */
 117 static struct lov_lock *lov_lock_sub_init(const struct lu_env *env,
 118                                           const struct cl_object *obj,
 119                                           struct cl_lock *lock)
 120 {
 121         int result = 0;
 122         int i;
 123         int nr;
 124         loff_t start;
 125         loff_t end;
 126         loff_t file_start;
 127         loff_t file_end;
 128
 129         struct lov_object       *loo    = cl2lov(obj);
 130         struct lov_layout_raid0 *r0     = lov_r0(loo);
 131         struct lov_lock         *lovlck;
 132
 133         ENTRY;
 134
 135         CDEBUG(D_INODE, "%p: lock/io FID "DFID"/"DFID", lock/io clobj %p/%p\n",
 136                loo, PFID(lu_object_fid(lov2lu(loo))),
 137                PFID(lu_object_fid(&obj->co_lu)),
 138                lov2cl(loo), obj);
 139
 140         file_start = cl_offset(lov2cl(loo), lock->cll_descr.cld_start);
 141         file_end   = cl_offset(lov2cl(loo), lock->cll_descr.cld_end + 1) - 1;
 142
 143         for (i = 0, nr = 0; i < r0->lo_nr; i++) {
 144                 /*
 145                  * XXX for wide striping smarter algorithm is desirable,
 146                  * breaking out of the loop, early.
 147                  */
 148                 if (likely(r0->lo_sub[i] != NULL) && /* spare layout */
 149                     lov_stripe_intersects(loo->lo_lsm, i,
 150                                           file_start, file_end, &start, &end))
 151                         nr++;
 152         }
 153         LASSERT(nr > 0);
 154
 155         OBD_ALLOC_LARGE(lovlck, offsetof(struct lov_lock, lls_sub[nr]));
 156         if (lovlck == NULL)
 157                 RETURN(ERR_PTR(-ENOMEM));
 158
 159         lovlck->lls_nr = nr;
 160         for (i = 0, nr = 0; i < r0->lo_nr; ++i) {
 161                 if (likely(r0->lo_sub[i] != NULL) &&
 162                     lov_stripe_intersects(loo->lo_lsm, i,
 163                                           file_start, file_end, &start, &end)) {
 164                         struct lov_lock_sub *lls = &lovlck->lls_sub[nr];
 165                         struct cl_lock_descr *descr;
 166
 167                         descr = &lls->sub_lock.cll_descr;
 168
 169                         LASSERT(descr->cld_obj == NULL);
 170                         descr->cld_obj   = lovsub2cl(r0->lo_sub[i]);
 171                         descr->cld_start = cl_index(descr->cld_obj, start);
 172                         descr->cld_end   = cl_index(descr->cld_obj, end);
 173                         descr->cld_mode  = lock->cll_descr.cld_mode;
 174                         descr->cld_gid   = lock->cll_descr.cld_gid;
 175                         descr->cld_enq_flags = lock->cll_descr.cld_enq_flags;
 176
 177                         lls->sub_stripe = i;
 178
 179                         /* initialize sub lock */
 180                         result = lov_sublock_init(env, lock, lls);
 181                         if (result < 0)
 182                                 break;
 183
 184                         lls->sub_initialized = 1;
 185                         nr++;
 186                 }
 187         }
 188         LASSERT(ergo(result == 0, nr == lovlck->lls_nr));
 189
 190         if (result != 0) {
 191                 for (i = 0; i < nr; ++i) {
 192                         if (!lovlck->lls_sub[i].sub_initialized)
 193                                 break;
 194
 195                         cl_lock_fini(env, &lovlck->lls_sub[i].sub_lock);
 196                 }
 197
 198                 OBD_FREE_LARGE(lovlck,
 199                                 offsetof(struct lov_lock, lls_sub[nr]));
 200                 lovlck = ERR_PTR(result);
 201         }
 202
 203         RETURN(lovlck);
 204 }
 205
 206 static void lov_lock_fini(const struct lu_env *env,
 207                           struct cl_lock_slice *slice)
 208 {
 209         struct lov_lock *lovlck;
 210         int i;
 211
 212         ENTRY;
 213         lovlck = cl2lov_lock(slice);
 214         for (i = 0; i < lovlck->lls_nr; ++i) {
 215                 LASSERT(!lovlck->lls_sub[i].sub_is_enqueued);
 216                 if (lovlck->lls_sub[i].sub_initialized)
 217                         cl_lock_fini(env, &lovlck->lls_sub[i].sub_lock);
 218         }
 219         OBD_FREE_LARGE(lovlck,
 220                        offsetof(struct lov_lock, lls_sub[lovlck->lls_nr]));
 221         EXIT;
 222 }
 223
 224 /**
 225  * Implementation of cl_lock_operations::clo_enqueue() for lov layer. This
 226  * function is rather subtle, as it enqueues top-lock (i.e., advances top-lock
 227  * state machine from CLS_QUEUING to CLS_ENQUEUED states) by juggling sub-lock
 228  * state machines in the face of sub-locks sharing (by multiple top-locks),
 229  * and concurrent sub-lock cancellations.
 230  */
 231 static int lov_lock_enqueue(const struct lu_env *env,
 232                             const struct cl_lock_slice *slice,
 233                             struct cl_io *io, struct cl_sync_io *anchor)
 234 {
 235         struct cl_lock          *lock   = slice->cls_lock;
 236         struct lov_lock         *lovlck = cl2lov_lock(slice);
 237         int                     i;
 238         int                     rc      = 0;
 239
 240         ENTRY;
 241
 242         for (i = 0; i < lovlck->lls_nr; ++i) {
 243                 struct lov_lock_sub     *lls = &lovlck->lls_sub[i];
 244                 struct lov_sublock_env  *subenv;
 245
 246                 subenv = lov_sublock_env_get(env, lock, lls);
 247                 if (IS_ERR(subenv)) {
 248                         rc = PTR_ERR(subenv);
 249                         break;
 250                 }
 251
 252                 rc = cl_lock_enqueue(subenv->lse_env, subenv->lse_io,
 253                                      &lls->sub_lock, anchor);
 254                 if (rc != 0)
 255                         break;
 256
 257                 lls->sub_is_enqueued = 1;
 258         }
 259         RETURN(rc);
 260 }
 261
 262 static void lov_lock_cancel(const struct lu_env *env,
 263                             const struct cl_lock_slice *slice)
 264 {
 265         struct cl_lock  *lock   = slice->cls_lock;
 266         struct lov_lock *lovlck = cl2lov_lock(slice);
 267         int i;
 268
 269         ENTRY;
 270
 271         for (i = 0; i < lovlck->lls_nr; ++i) {
 272                 struct lov_lock_sub     *lls = &lovlck->lls_sub[i];
 273                 struct cl_lock          *sublock = &lls->sub_lock;
 274                 struct lov_sublock_env  *subenv;
 275
 276                 if (!lls->sub_is_enqueued)
 277                         continue;
 278
 279                 lls->sub_is_enqueued = 0;
 280                 subenv = lov_sublock_env_get(env, lock, lls);
 281                 if (!IS_ERR(subenv)) {
 282                         cl_lock_cancel(subenv->lse_env, sublock);
 283                 } else {
 284                         CL_LOCK_DEBUG(D_ERROR, env, slice->cls_lock,
 285                                       "lov_lock_cancel fails with %ld.\n",
 286                                       PTR_ERR(subenv));
 287                 }
 288         }
 289 }
 290
 291 static int lov_lock_print(const struct lu_env *env, void *cookie,
 292                           lu_printer_t p, const struct cl_lock_slice *slice)
 293 {
 294         struct lov_lock *lck = cl2lov_lock(slice);
 295         int              i;
 296
 297         (*p)(env, cookie, "%d\n", lck->lls_nr);
 298         for (i = 0; i < lck->lls_nr; ++i) {
 299                 struct lov_lock_sub *sub;
 300
 301                 sub = &lck->lls_sub[i];
 302                 (*p)(env, cookie, "    %d %x: ", i, sub->sub_is_enqueued);
 303                 cl_lock_print(env, cookie, p, &sub->sub_lock);
 304         }
 305         return 0;
 306 }
 307
 308 static const struct cl_lock_operations lov_lock_ops = {
 309         .clo_fini      = lov_lock_fini,
 310         .clo_enqueue   = lov_lock_enqueue,
 311         .clo_cancel    = lov_lock_cancel,
 312         .clo_print     = lov_lock_print
 313 };
 314
 315 int lov_lock_init_raid0(const struct lu_env *env, struct cl_object *obj,
 316                         struct cl_lock *lock, const struct cl_io *io)
 317 {
 318         struct lov_lock *lck;
 319         int result = 0;
 320
 321         ENTRY;
 322         lck = lov_lock_sub_init(env, obj, lock);
 323         if (!IS_ERR(lck))
 324                 cl_lock_slice_add(lock, &lck->lls_cl, obj, &lov_lock_ops);
 325         else
 326                 result = PTR_ERR(lck);
 327         RETURN(result);
 328 }
 329
 330 static void lov_empty_lock_fini(const struct lu_env *env,
 331                                 struct cl_lock_slice *slice)
 332 {
 333         struct lov_lock *lck = cl2lov_lock(slice);
 334         OBD_SLAB_FREE_PTR(lck, lov_lock_kmem);
 335 }
 336
 337 static int lov_empty_lock_print(const struct lu_env *env, void *cookie,
 338                         lu_printer_t p, const struct cl_lock_slice *slice)
 339 {
 340         (*p)(env, cookie, "empty\n");
 341         return 0;
 342 }
 343
 344 /* XXX: more methods will be added later. */
 345 static const struct cl_lock_operations lov_empty_lock_ops = {
 346         .clo_fini  = lov_empty_lock_fini,
 347         .clo_print = lov_empty_lock_print
 348 };
 349
 350 int lov_lock_init_empty(const struct lu_env *env, struct cl_object *obj,
 351                         struct cl_lock *lock, const struct cl_io *io)
 352 {
 353         struct lov_lock *lck;
 354         int result = -ENOMEM;
 355
 356         ENTRY;
 357         OBD_SLAB_ALLOC_PTR_GFP(lck, lov_lock_kmem, GFP_NOFS);
 358         if (lck != NULL) {
 359                 cl_lock_slice_add(lock, &lck->lls_cl, obj, &lov_empty_lock_ops);
 360                 result = 0;
 361         }
 362         RETURN(result);
 363 }
 364
 365 /** @} lov */