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.gnu.org/licenses/gpl-2.0.html
  19  *
  20  * GPL HEADER END
  21  */
  22 /*
  23  * Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
  24  * Use is subject to license terms.
  25  *
  26  * Copyright (c) 2011, 2016, Intel Corporation.
  27  */
  28 /*
  29  * This file is part of Lustre, http://www.lustre.org/
  30  * Lustre is a trademark of Sun Microsystems, Inc.
  31  *
  32  * Implementation of cl_lock for LOV layer.
  33  *
  34  *   Author: Nikita Danilov <nikita.danilov@sun.com>
  35  */
  36
  37 #define DEBUG_SUBSYSTEM S_LOV
  38
  39 #include "lov_cl_internal.h"
  40
  41 /** \addtogroup lov
  42  *  @{
  43  */
  44
  45 /*****************************************************************************
  46  *
  47  * Lov lock operations.
  48  *
  49  */
  50
  51 static struct lov_sublock_env *lov_sublock_env_get(const struct lu_env *env,
  52                                                    const struct cl_lock *parent,
  53                                                    struct lov_lock_sub *lls)
  54 {
  55         struct lov_sublock_env *subenv;
  56         struct lov_io          *lio    = lov_env_io(env);
  57         struct cl_io           *io     = lio->lis_cl.cis_io;
  58         struct lov_io_sub      *sub;
  59
  60         subenv = &lov_env_session(env)->ls_subenv;
  61
  62         /*
  63          * FIXME: We tend to use the subio's env & io to call the sublock
  64          * lock operations because osc lock sometimes stores some control
  65          * variables in thread's IO infomation(Now only lockless information).
  66          * However, if the lock's host(object) is different from the object
  67          * for current IO, we have no way to get the subenv and subio because
  68          * they are not initialized at all. As a temp fix, in this case,
  69          * we still borrow the parent's env to call sublock operations.
  70          */
  71         if (!io || !cl_object_same(io->ci_obj, parent->cll_descr.cld_obj)) {
  72                 subenv->lse_env = env;
  73                 subenv->lse_io = io;
  74         } else {
  75                 sub = lov_sub_get(env, lio, lls->sub_index);
  76                 if (!IS_ERR(sub)) {
  77                         subenv->lse_env = sub->sub_env;
  78                         subenv->lse_io  = &sub->sub_io;
  79                 } else {
  80                         subenv = (void *)sub;
  81                 }
  82         }
  83         return subenv;
  84 }
  85
  86 static int lov_sublock_init(const struct lu_env *env,
  87                             const struct cl_lock *parent,
  88                             struct lov_lock_sub *lls)
  89 {
  90         struct lov_sublock_env *subenv;
  91         int result;
  92         ENTRY;
  93
  94         subenv = lov_sublock_env_get(env, parent, lls);
  95         if (!IS_ERR(subenv)) {
  96                 result = cl_lock_init(subenv->lse_env, &lls->sub_lock,
  97                                       subenv->lse_io);
  98         } else {
  99                 /* error occurs. */
 100                 result = PTR_ERR(subenv);
 101         }
 102         RETURN(result);
 103 }
 104
 105 /**
 106  * Creates sub-locks for a given lov_lock for the first time.
 107  *
 108  * Goes through all sub-objects of top-object, and creates sub-locks on every
 109  * sub-object intersecting with top-lock extent. This is complicated by the
 110  * fact that top-lock (that is being created) can be accessed concurrently
 111  * through already created sub-locks (possibly shared with other top-locks).
 112  */
 113 static struct lov_lock *lov_lock_sub_init(const struct lu_env *env,
 114                                           const struct cl_object *obj,
 115                                           struct cl_lock *lock)
 116 {
 117         struct lov_object *lov = cl2lov(obj);
 118         struct lov_lock *lovlck;
 119         struct lu_extent ext;
 120         loff_t start;
 121         loff_t end;
 122         int result = 0;
 123         int i;
 124         int index;
 125         int nr;
 126
 127         ENTRY;
 128
 129         ext.e_start = cl_offset(obj, lock->cll_descr.cld_start);
 130         if (lock->cll_descr.cld_end == CL_PAGE_EOF)
 131                 ext.e_end = OBD_OBJECT_EOF;
 132         else
 133                 ext.e_end  = cl_offset(obj, lock->cll_descr.cld_end + 1);
 134
 135         nr = 0;
 136         for (index = lov_lsm_entry(lov->lo_lsm, ext.e_start);
 137              index != -1 && index < lov->lo_lsm->lsm_entry_count; index++) {
 138                 struct lov_layout_raid0 *r0 = lov_r0(lov, index);
 139
 140                 /* assume lsm entries are sorted. */
 141                 if (!lu_extent_is_overlapped(&ext,
 142                                              &lov_lse(lov, index)->lsme_extent))
 143                         break;
 144
 145                 for (i = 0; i < r0->lo_nr; i++) {
 146                         if (likely(r0->lo_sub[i] != NULL) && /* spare layout */
 147                             lov_stripe_intersects(lov->lo_lsm, index, i,
 148                                                   &ext, &start, &end))
 149                                 nr++;
 150                 }
 151         }
 152         if (nr == 0)
 153                 RETURN(ERR_PTR(-EINVAL));
 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         nr = 0;
 161         for (index = lov_lsm_entry(lov->lo_lsm, ext.e_start);
 162              index < lov->lo_lsm->lsm_entry_count; index++) {
 163                 struct lov_layout_raid0 *r0 = lov_r0(lov, index);
 164
 165                 /* assume lsm entries are sorted. */
 166                 if (!lu_extent_is_overlapped(&ext,
 167                                              &lov_lse(lov, index)->lsme_extent))
 168                         break;
 169                 for (i = 0; i < r0->lo_nr; ++i) {
 170                         struct lov_lock_sub *lls = &lovlck->lls_sub[nr];
 171                         struct cl_lock_descr *descr = &lls->sub_lock.cll_descr;
 172
 173                         if (unlikely(r0->lo_sub[i] == NULL) ||
 174                             !lov_stripe_intersects(lov->lo_lsm, index, i,
 175                                                    &ext, &start, &end))
 176                                 continue;
 177
 178                         LASSERT(descr->cld_obj == NULL);
 179                         descr->cld_obj   = lovsub2cl(r0->lo_sub[i]);
 180                         descr->cld_start = cl_index(descr->cld_obj, start);
 181                         descr->cld_end   = cl_index(descr->cld_obj, end);
 182                         descr->cld_mode  = lock->cll_descr.cld_mode;
 183                         descr->cld_gid   = lock->cll_descr.cld_gid;
 184                         descr->cld_enq_flags = lock->cll_descr.cld_enq_flags;
 185
 186                         lls->sub_index = lov_comp_index(index, i);
 187
 188                         /* initialize sub lock */
 189                         result = lov_sublock_init(env, lock, lls);
 190                         if (result < 0)
 191                                 break;
 192
 193                         lls->sub_initialized = 1;
 194                         nr++;
 195                 }
 196         }
 197         LASSERT(ergo(result == 0, nr == lovlck->lls_nr));
 198
 199         if (result != 0) {
 200                 for (i = 0; i < nr; ++i) {
 201                         if (!lovlck->lls_sub[i].sub_initialized)
 202                                 break;
 203
 204                         cl_lock_fini(env, &lovlck->lls_sub[i].sub_lock);
 205                 }
 206
 207                 OBD_FREE_LARGE(lovlck,
 208                                 offsetof(struct lov_lock, lls_sub[nr]));
 209                 lovlck = ERR_PTR(result);
 210         }
 211
 212         RETURN(lovlck);
 213 }
 214
 215 static void lov_lock_fini(const struct lu_env *env,
 216                           struct cl_lock_slice *slice)
 217 {
 218         struct lov_lock *lovlck;
 219         int i;
 220
 221         ENTRY;
 222         lovlck = cl2lov_lock(slice);
 223         for (i = 0; i < lovlck->lls_nr; ++i) {
 224                 LASSERT(!lovlck->lls_sub[i].sub_is_enqueued);
 225                 if (lovlck->lls_sub[i].sub_initialized)
 226                         cl_lock_fini(env, &lovlck->lls_sub[i].sub_lock);
 227         }
 228         OBD_FREE_LARGE(lovlck,
 229                        offsetof(struct lov_lock, lls_sub[lovlck->lls_nr]));
 230         EXIT;
 231 }
 232
 233 /**
 234  * Implementation of cl_lock_operations::clo_enqueue() for lov layer. This
 235  * function is rather subtle, as it enqueues top-lock (i.e., advances top-lock
 236  * state machine from CLS_QUEUING to CLS_ENQUEUED states) by juggling sub-lock
 237  * state machines in the face of sub-locks sharing (by multiple top-locks),
 238  * and concurrent sub-lock cancellations.
 239  */
 240 static int lov_lock_enqueue(const struct lu_env *env,
 241                             const struct cl_lock_slice *slice,
 242                             struct cl_io *io, struct cl_sync_io *anchor)
 243 {
 244         struct cl_lock          *lock   = slice->cls_lock;
 245         struct lov_lock         *lovlck = cl2lov_lock(slice);
 246         int                     i;
 247         int                     rc      = 0;
 248
 249         ENTRY;
 250
 251         for (i = 0; i < lovlck->lls_nr; ++i) {
 252                 struct lov_lock_sub     *lls = &lovlck->lls_sub[i];
 253                 struct lov_sublock_env  *subenv;
 254
 255                 subenv = lov_sublock_env_get(env, lock, lls);
 256                 if (IS_ERR(subenv)) {
 257                         rc = PTR_ERR(subenv);
 258                         break;
 259                 }
 260
 261                 rc = cl_lock_enqueue(subenv->lse_env, subenv->lse_io,
 262                                      &lls->sub_lock, anchor);
 263                 if (rc != 0)
 264                         break;
 265
 266                 lls->sub_is_enqueued = 1;
 267         }
 268         RETURN(rc);
 269 }
 270
 271 static void lov_lock_cancel(const struct lu_env *env,
 272                             const struct cl_lock_slice *slice)
 273 {
 274         struct cl_lock  *lock   = slice->cls_lock;
 275         struct lov_lock *lovlck = cl2lov_lock(slice);
 276         int i;
 277
 278         ENTRY;
 279
 280         for (i = 0; i < lovlck->lls_nr; ++i) {
 281                 struct lov_lock_sub     *lls = &lovlck->lls_sub[i];
 282                 struct cl_lock          *sublock = &lls->sub_lock;
 283                 struct lov_sublock_env  *subenv;
 284
 285                 if (!lls->sub_is_enqueued)
 286                         continue;
 287
 288                 lls->sub_is_enqueued = 0;
 289                 subenv = lov_sublock_env_get(env, lock, lls);
 290                 if (!IS_ERR(subenv)) {
 291                         cl_lock_cancel(subenv->lse_env, sublock);
 292                 } else {
 293                         CL_LOCK_DEBUG(D_ERROR, env, slice->cls_lock,
 294                                       "lov_lock_cancel fails with %ld.\n",
 295                                       PTR_ERR(subenv));
 296                 }
 297         }
 298 }
 299
 300 static int lov_lock_print(const struct lu_env *env, void *cookie,
 301                           lu_printer_t p, const struct cl_lock_slice *slice)
 302 {
 303         struct lov_lock *lck = cl2lov_lock(slice);
 304         int              i;
 305
 306         (*p)(env, cookie, "%d\n", lck->lls_nr);
 307         for (i = 0; i < lck->lls_nr; ++i) {
 308                 struct lov_lock_sub *sub;
 309
 310                 sub = &lck->lls_sub[i];
 311                 (*p)(env, cookie, "    %d %x: ", i, sub->sub_is_enqueued);
 312                 cl_lock_print(env, cookie, p, &sub->sub_lock);
 313         }
 314         return 0;
 315 }
 316
 317 static const struct cl_lock_operations lov_lock_ops = {
 318         .clo_fini      = lov_lock_fini,
 319         .clo_enqueue   = lov_lock_enqueue,
 320         .clo_cancel    = lov_lock_cancel,
 321         .clo_print     = lov_lock_print
 322 };
 323
 324 int lov_lock_init_composite(const struct lu_env *env, struct cl_object *obj,
 325                             struct cl_lock *lock, const struct cl_io *io)
 326 {
 327         struct lov_lock *lck;
 328         int result = 0;
 329
 330         ENTRY;
 331         lck = lov_lock_sub_init(env, obj, lock);
 332         if (!IS_ERR(lck))
 333                 cl_lock_slice_add(lock, &lck->lls_cl, obj, &lov_lock_ops);
 334         else
 335                 result = PTR_ERR(lck);
 336         RETURN(result);
 337 }
 338
 339 static void lov_empty_lock_fini(const struct lu_env *env,
 340                                 struct cl_lock_slice *slice)
 341 {
 342         struct lov_lock *lck = cl2lov_lock(slice);
 343         OBD_SLAB_FREE_PTR(lck, lov_lock_kmem);
 344 }
 345
 346 static int lov_empty_lock_print(const struct lu_env *env, void *cookie,
 347                         lu_printer_t p, const struct cl_lock_slice *slice)
 348 {
 349         (*p)(env, cookie, "empty\n");
 350         return 0;
 351 }
 352
 353 /* XXX: more methods will be added later. */
 354 static const struct cl_lock_operations lov_empty_lock_ops = {
 355         .clo_fini  = lov_empty_lock_fini,
 356         .clo_print = lov_empty_lock_print
 357 };
 358
 359 int lov_lock_init_empty(const struct lu_env *env, struct cl_object *obj,
 360                         struct cl_lock *lock, const struct cl_io *io)
 361 {
 362         struct lov_lock *lck;
 363         int result = -ENOMEM;
 364
 365         ENTRY;
 366         OBD_SLAB_ALLOC_PTR_GFP(lck, lov_lock_kmem, GFP_NOFS);
 367         if (lck != NULL) {
 368                 cl_lock_slice_add(lock, &lck->lls_cl, obj, &lov_empty_lock_ops);
 369                 result = 0;
 370         }
 371         RETURN(result);
 372 }
 373
 374 /** @} lov */