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_stripe);
  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         int result = 0;
 118         int i;
 119         int nr;
 120         loff_t start;
 121         loff_t end;
 122         loff_t file_start;
 123         loff_t file_end;
 124
 125         struct lov_object       *loo    = cl2lov(obj);
 126         struct lov_layout_raid0 *r0     = lov_r0(loo);
 127         struct lov_lock         *lovlck;
 128
 129         ENTRY;
 130
 131         CDEBUG(D_INODE, "%p: lock/io FID "DFID"/"DFID", lock/io clobj %p/%p\n",
 132                loo, PFID(lu_object_fid(lov2lu(loo))),
 133                PFID(lu_object_fid(&obj->co_lu)),
 134                lov2cl(loo), obj);
 135
 136         file_start = cl_offset(lov2cl(loo), lock->cll_descr.cld_start);
 137         file_end   = cl_offset(lov2cl(loo), lock->cll_descr.cld_end + 1) - 1;
 138
 139         for (i = 0, nr = 0; i < r0->lo_nr; i++) {
 140                 /*
 141                  * XXX for wide striping smarter algorithm is desirable,
 142                  * breaking out of the loop, early.
 143                  */
 144                 if (likely(r0->lo_sub[i] != NULL) && /* spare layout */
 145                     lov_stripe_intersects(loo->lo_lsm, i,
 146                                           file_start, file_end, &start, &end))
 147                         nr++;
 148         }
 149         LASSERT(nr > 0);
 150
 151         OBD_ALLOC_LARGE(lovlck, offsetof(struct lov_lock, lls_sub[nr]));
 152         if (lovlck == NULL)
 153                 RETURN(ERR_PTR(-ENOMEM));
 154
 155         lovlck->lls_nr = nr;
 156         for (i = 0, nr = 0; i < r0->lo_nr; ++i) {
 157                 if (likely(r0->lo_sub[i] != NULL) &&
 158                     lov_stripe_intersects(loo->lo_lsm, i,
 159                                           file_start, file_end, &start, &end)) {
 160                         struct lov_lock_sub *lls = &lovlck->lls_sub[nr];
 161                         struct cl_lock_descr *descr;
 162
 163                         descr = &lls->sub_lock.cll_descr;
 164
 165                         LASSERT(descr->cld_obj == NULL);
 166                         descr->cld_obj   = lovsub2cl(r0->lo_sub[i]);
 167                         descr->cld_start = cl_index(descr->cld_obj, start);
 168                         descr->cld_end   = cl_index(descr->cld_obj, end);
 169                         descr->cld_mode  = lock->cll_descr.cld_mode;
 170                         descr->cld_gid   = lock->cll_descr.cld_gid;
 171                         descr->cld_enq_flags = lock->cll_descr.cld_enq_flags;
 172
 173                         lls->sub_stripe = i;
 174
 175                         /* initialize sub lock */
 176                         result = lov_sublock_init(env, lock, lls);
 177                         if (result < 0)
 178                                 break;
 179
 180                         lls->sub_initialized = 1;
 181                         nr++;
 182                 }
 183         }
 184         LASSERT(ergo(result == 0, nr == lovlck->lls_nr));
 185
 186         if (result != 0) {
 187                 for (i = 0; i < nr; ++i) {
 188                         if (!lovlck->lls_sub[i].sub_initialized)
 189                                 break;
 190
 191                         cl_lock_fini(env, &lovlck->lls_sub[i].sub_lock);
 192                 }
 193
 194                 OBD_FREE_LARGE(lovlck,
 195                                 offsetof(struct lov_lock, lls_sub[nr]));
 196                 lovlck = ERR_PTR(result);
 197         }
 198
 199         RETURN(lovlck);
 200 }
 201
 202 static void lov_lock_fini(const struct lu_env *env,
 203                           struct cl_lock_slice *slice)
 204 {
 205         struct lov_lock *lovlck;
 206         int i;
 207
 208         ENTRY;
 209         lovlck = cl2lov_lock(slice);
 210         for (i = 0; i < lovlck->lls_nr; ++i) {
 211                 LASSERT(!lovlck->lls_sub[i].sub_is_enqueued);
 212                 if (lovlck->lls_sub[i].sub_initialized)
 213                         cl_lock_fini(env, &lovlck->lls_sub[i].sub_lock);
 214         }
 215         OBD_FREE_LARGE(lovlck,
 216                        offsetof(struct lov_lock, lls_sub[lovlck->lls_nr]));
 217         EXIT;
 218 }
 219
 220 /**
 221  * Implementation of cl_lock_operations::clo_enqueue() for lov layer. This
 222  * function is rather subtle, as it enqueues top-lock (i.e., advances top-lock
 223  * state machine from CLS_QUEUING to CLS_ENQUEUED states) by juggling sub-lock
 224  * state machines in the face of sub-locks sharing (by multiple top-locks),
 225  * and concurrent sub-lock cancellations.
 226  */
 227 static int lov_lock_enqueue(const struct lu_env *env,
 228                             const struct cl_lock_slice *slice,
 229                             struct cl_io *io, struct cl_sync_io *anchor)
 230 {
 231         struct cl_lock          *lock   = slice->cls_lock;
 232         struct lov_lock         *lovlck = cl2lov_lock(slice);
 233         int                     i;
 234         int                     rc      = 0;
 235
 236         ENTRY;
 237
 238         for (i = 0; i < lovlck->lls_nr; ++i) {
 239                 struct lov_lock_sub     *lls = &lovlck->lls_sub[i];
 240                 struct lov_sublock_env  *subenv;
 241
 242                 subenv = lov_sublock_env_get(env, lock, lls);
 243                 if (IS_ERR(subenv)) {
 244                         rc = PTR_ERR(subenv);
 245                         break;
 246                 }
 247
 248                 rc = cl_lock_enqueue(subenv->lse_env, subenv->lse_io,
 249                                      &lls->sub_lock, anchor);
 250                 if (rc != 0)
 251                         break;
 252
 253                 lls->sub_is_enqueued = 1;
 254         }
 255         RETURN(rc);
 256 }
 257
 258 static void lov_lock_cancel(const struct lu_env *env,
 259                             const struct cl_lock_slice *slice)
 260 {
 261         struct cl_lock  *lock   = slice->cls_lock;
 262         struct lov_lock *lovlck = cl2lov_lock(slice);
 263         int i;
 264
 265         ENTRY;
 266
 267         for (i = 0; i < lovlck->lls_nr; ++i) {
 268                 struct lov_lock_sub     *lls = &lovlck->lls_sub[i];
 269                 struct cl_lock          *sublock = &lls->sub_lock;
 270                 struct lov_sublock_env  *subenv;
 271
 272                 if (!lls->sub_is_enqueued)
 273                         continue;
 274
 275                 lls->sub_is_enqueued = 0;
 276                 subenv = lov_sublock_env_get(env, lock, lls);
 277                 if (!IS_ERR(subenv)) {
 278                         cl_lock_cancel(subenv->lse_env, sublock);
 279                 } else {
 280                         CL_LOCK_DEBUG(D_ERROR, env, slice->cls_lock,
 281                                       "lov_lock_cancel fails with %ld.\n",
 282                                       PTR_ERR(subenv));
 283                 }
 284         }
 285 }
 286
 287 static int lov_lock_print(const struct lu_env *env, void *cookie,
 288                           lu_printer_t p, const struct cl_lock_slice *slice)
 289 {
 290         struct lov_lock *lck = cl2lov_lock(slice);
 291         int              i;
 292
 293         (*p)(env, cookie, "%d\n", lck->lls_nr);
 294         for (i = 0; i < lck->lls_nr; ++i) {
 295                 struct lov_lock_sub *sub;
 296
 297                 sub = &lck->lls_sub[i];
 298                 (*p)(env, cookie, "    %d %x: ", i, sub->sub_is_enqueued);
 299                 cl_lock_print(env, cookie, p, &sub->sub_lock);
 300         }
 301         return 0;
 302 }
 303
 304 static const struct cl_lock_operations lov_lock_ops = {
 305         .clo_fini      = lov_lock_fini,
 306         .clo_enqueue   = lov_lock_enqueue,
 307         .clo_cancel    = lov_lock_cancel,
 308         .clo_print     = lov_lock_print
 309 };
 310
 311 int lov_lock_init_raid0(const struct lu_env *env, struct cl_object *obj,
 312                         struct cl_lock *lock, const struct cl_io *io)
 313 {
 314         struct lov_lock *lck;
 315         int result = 0;
 316
 317         ENTRY;
 318         lck = lov_lock_sub_init(env, obj, lock);
 319         if (!IS_ERR(lck))
 320                 cl_lock_slice_add(lock, &lck->lls_cl, obj, &lov_lock_ops);
 321         else
 322                 result = PTR_ERR(lck);
 323         RETURN(result);
 324 }
 325
 326 static void lov_empty_lock_fini(const struct lu_env *env,
 327                                 struct cl_lock_slice *slice)
 328 {
 329         struct lov_lock *lck = cl2lov_lock(slice);
 330         OBD_SLAB_FREE_PTR(lck, lov_lock_kmem);
 331 }
 332
 333 static int lov_empty_lock_print(const struct lu_env *env, void *cookie,
 334                         lu_printer_t p, const struct cl_lock_slice *slice)
 335 {
 336         (*p)(env, cookie, "empty\n");
 337         return 0;
 338 }
 339
 340 /* XXX: more methods will be added later. */
 341 static const struct cl_lock_operations lov_empty_lock_ops = {
 342         .clo_fini  = lov_empty_lock_fini,
 343         .clo_print = lov_empty_lock_print
 344 };
 345
 346 int lov_lock_init_empty(const struct lu_env *env, struct cl_object *obj,
 347                         struct cl_lock *lock, const struct cl_io *io)
 348 {
 349         struct lov_lock *lck;
 350         int result = -ENOMEM;
 351
 352         ENTRY;
 353         OBD_SLAB_ALLOC_PTR_GFP(lck, lov_lock_kmem, GFP_NOFS);
 354         if (lck != NULL) {
 355                 cl_lock_slice_add(lock, &lck->lls_cl, obj, &lov_empty_lock_ops);
 356                 result = 0;
 357         }
 358         RETURN(result);
 359 }
 360
 361 /** @} lov */