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, 2017, Intel Corporation.
  27  */
  28 /*
  29  * This file is part of Lustre, http://www.lustre.org/
  30  *
  31  * Implementation of cl_lock for LOV layer.
  32  *
  33  *   Author: Nikita Danilov <nikita.danilov@sun.com>
  34  */
  35
  36 #define DEBUG_SUBSYSTEM S_LOV
  37
  38 #include "lov_cl_internal.h"
  39
  40 /** \addtogroup lov
  41  *  @{
  42  */
  43
  44 /*****************************************************************************
  45  *
  46  * Lov lock operations.
  47  *
  48  */
  49
  50 static struct lov_sublock_env *lov_sublock_env_get(const struct lu_env *env,
  51                                                    const struct cl_lock *parent,
  52                                                    struct lov_lock_sub *lls)
  53 {
  54         struct lov_sublock_env *subenv;
  55         struct lov_io          *lio    = lov_env_io(env);
  56         struct cl_io           *io     = lio->lis_cl.cis_io;
  57         struct lov_io_sub      *sub;
  58
  59         subenv = &lov_env_session(env)->ls_subenv;
  60
  61         /*
  62          * FIXME: We tend to use the subio's env & io to call the sublock
  63          * lock operations because osc lock sometimes stores some control
  64          * variables in thread's IO infomation(Now only lockless information).
  65          * However, if the lock's host(object) is different from the object
  66          * for current IO, we have no way to get the subenv and subio because
  67          * they are not initialized at all. As a temp fix, in this case,
  68          * we still borrow the parent's env to call sublock operations.
  69          */
  70         if (!io || !cl_object_same(io->ci_obj, parent->cll_descr.cld_obj)) {
  71                 subenv->lse_env = env;
  72                 subenv->lse_io = io;
  73         } else {
  74                 sub = lov_sub_get(env, lio, lls->sub_index);
  75                 if (!IS_ERR(sub)) {
  76                         subenv->lse_env = sub->sub_env;
  77                         subenv->lse_io  = &sub->sub_io;
  78                 } else {
  79                         subenv = (void *)sub;
  80                 }
  81         }
  82         return subenv;
  83 }
  84
  85 static int lov_sublock_init(const struct lu_env *env,
  86                             const struct cl_lock *parent,
  87                             struct lov_lock_sub *lls)
  88 {
  89         struct lov_sublock_env *subenv;
  90         int result;
  91
  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_io *io,
 115                                           const struct cl_object *obj,
 116                                           struct cl_lock *lock)
 117 {
 118         struct lov_object *lov = cl2lov(obj);
 119         struct lov_lock *lovlck;
 120         struct lu_extent ext;
 121         loff_t start;
 122         loff_t end;
 123         int result = 0;
 124         int i;
 125         int index;
 126         int nr;
 127
 128         ENTRY;
 129
 130         ext.e_start = cl_offset(obj, lock->cll_descr.cld_start);
 131         if (lock->cll_descr.cld_end == CL_PAGE_EOF)
 132                 ext.e_end = OBD_OBJECT_EOF;
 133         else
 134                 ext.e_end  = cl_offset(obj, lock->cll_descr.cld_end + 1);
 135
 136         nr = 0;
 137         lov_foreach_io_layout(index, lov_env_io(env), &ext) {
 138                 struct lov_layout_raid0 *r0 = lov_r0(lov, index);
 139
 140                 for (i = 0; i < r0->lo_nr; i++) {
 141                         if (likely(r0->lo_sub[i])) {/* spare layout */
 142                                 if (lov_stripe_intersects(lov->lo_lsm, index, i,
 143                                                           &ext, &start, &end))
 144                                         nr++;
 145                                 else if (cl_io_is_trunc(io) &&
 146                                          r0->lo_trunc_stripeno == i)
 147                                         nr++;
 148                         }
 149                 }
 150         }
 151         /**
 152          * Aggressive lock request (from cl_setattr_ost) which asks for
 153          * [eof, -1) lock, could come across uninstantiated layout extent,
 154          * hence a 0 nr is possible.
 155          */
 156
 157         OBD_ALLOC_LARGE(lovlck, offsetof(struct lov_lock, lls_sub[nr]));
 158         if (!lovlck)
 159                 RETURN(ERR_PTR(-ENOMEM));
 160
 161         lovlck->lls_nr = nr;
 162         nr = 0;
 163         lov_foreach_io_layout(index, lov_env_io(env), &ext) {
 164                 struct lov_layout_raid0 *r0 = lov_r0(lov, index);
 165
 166                 for (i = 0; i < r0->lo_nr; ++i) {
 167                         struct lov_lock_sub *lls = &lovlck->lls_sub[nr];
 168                         struct cl_lock_descr *descr = &lls->sub_lock.cll_descr;
 169                         bool intersect = false;
 170
 171                         if (unlikely(!r0->lo_sub[i]))
 172                                 continue;
 173
 174                         intersect = lov_stripe_intersects(lov->lo_lsm, index, i,
 175                                                           &ext, &start, &end);
 176                         if (intersect)
 177                                 goto init_sublock;
 178
 179                         if (cl_io_is_trunc(io) && i == r0->lo_trunc_stripeno)
 180                                 goto init_sublock;
 181
 182                         continue;
 183
 184 init_sublock:
 185                         LASSERT(descr->cld_obj == NULL);
 186                         descr->cld_obj   = lovsub2cl(r0->lo_sub[i]);
 187                         descr->cld_start = cl_index(descr->cld_obj, start);
 188                         descr->cld_end   = cl_index(descr->cld_obj, end);
 189                         descr->cld_mode  = lock->cll_descr.cld_mode;
 190                         descr->cld_gid   = lock->cll_descr.cld_gid;
 191                         descr->cld_enq_flags = lock->cll_descr.cld_enq_flags;
 192
 193                         lls->sub_index = lov_comp_index(index, i);
 194
 195                         /* initialize sub lock */
 196                         result = lov_sublock_init(env, lock, lls);
 197                         if (result < 0)
 198                                 break;
 199
 200                         lls->sub_initialized = 1;
 201                         nr++;
 202                 }
 203                 if (result < 0)
 204                         break;
 205         }
 206         LASSERT(ergo(result == 0, nr == lovlck->lls_nr));
 207
 208         if (result != 0) {
 209                 for (i = 0; i < nr; ++i) {
 210                         if (!lovlck->lls_sub[i].sub_initialized)
 211                                 break;
 212
 213                         cl_lock_fini(env, &lovlck->lls_sub[i].sub_lock);
 214                 }
 215
 216                 OBD_FREE_LARGE(lovlck,
 217                                 offsetof(struct lov_lock, lls_sub[nr]));
 218                 lovlck = ERR_PTR(result);
 219         }
 220
 221         RETURN(lovlck);
 222 }
 223
 224 static void lov_lock_fini(const struct lu_env *env,
 225                           struct cl_lock_slice *slice)
 226 {
 227         struct lov_lock *lovlck;
 228         int i;
 229
 230         ENTRY;
 231         lovlck = cl2lov_lock(slice);
 232         for (i = 0; i < lovlck->lls_nr; ++i) {
 233                 LASSERT(!lovlck->lls_sub[i].sub_is_enqueued);
 234                 if (lovlck->lls_sub[i].sub_initialized)
 235                         cl_lock_fini(env, &lovlck->lls_sub[i].sub_lock);
 236         }
 237         OBD_FREE_LARGE(lovlck,
 238                        offsetof(struct lov_lock, lls_sub[lovlck->lls_nr]));
 239         EXIT;
 240 }
 241
 242 /**
 243  * Implementation of cl_lock_operations::clo_enqueue() for lov layer. This
 244  * function is rather subtle, as it enqueues top-lock (i.e., advances top-lock
 245  * state machine from CLS_QUEUING to CLS_ENQUEUED states) by juggling sub-lock
 246  * state machines in the face of sub-locks sharing (by multiple top-locks),
 247  * and concurrent sub-lock cancellations.
 248  */
 249 static int lov_lock_enqueue(const struct lu_env *env,
 250                             const struct cl_lock_slice *slice,
 251                             struct cl_io *io, struct cl_sync_io *anchor)
 252 {
 253         struct cl_lock *lock = slice->cls_lock;
 254         struct lov_lock *lovlck = cl2lov_lock(slice);
 255         int i;
 256         int rc = 0;
 257
 258         ENTRY;
 259
 260         for (i = 0; i < lovlck->lls_nr; ++i) {
 261                 struct lov_lock_sub     *lls = &lovlck->lls_sub[i];
 262                 struct lov_sublock_env  *subenv;
 263
 264                 subenv = lov_sublock_env_get(env, lock, lls);
 265                 if (IS_ERR(subenv)) {
 266                         rc = PTR_ERR(subenv);
 267                         break;
 268                 }
 269
 270                 rc = cl_lock_enqueue(subenv->lse_env, subenv->lse_io,
 271                                      &lls->sub_lock, anchor);
 272                 if (rc != 0)
 273                         break;
 274
 275                 lls->sub_is_enqueued = 1;
 276         }
 277         RETURN(rc);
 278 }
 279
 280 static void lov_lock_cancel(const struct lu_env *env,
 281                             const struct cl_lock_slice *slice)
 282 {
 283         struct cl_lock *lock = slice->cls_lock;
 284         struct lov_lock *lovlck = cl2lov_lock(slice);
 285         int i;
 286
 287         ENTRY;
 288
 289         for (i = 0; i < lovlck->lls_nr; ++i) {
 290                 struct lov_lock_sub *lls = &lovlck->lls_sub[i];
 291                 struct cl_lock *sublock = &lls->sub_lock;
 292                 struct lov_sublock_env *subenv;
 293
 294                 if (!lls->sub_is_enqueued)
 295                         continue;
 296
 297                 lls->sub_is_enqueued = 0;
 298                 subenv = lov_sublock_env_get(env, lock, lls);
 299                 if (!IS_ERR(subenv)) {
 300                         cl_lock_cancel(subenv->lse_env, sublock);
 301                 } else {
 302                         CL_LOCK_DEBUG(D_ERROR, env, slice->cls_lock,
 303                                       "lov_lock_cancel fails with %ld.\n",
 304                                       PTR_ERR(subenv));
 305                 }
 306         }
 307 }
 308
 309 static int lov_lock_print(const struct lu_env *env, void *cookie,
 310                           lu_printer_t p, const struct cl_lock_slice *slice)
 311 {
 312         struct lov_lock *lck = cl2lov_lock(slice);
 313         int i;
 314
 315         (*p)(env, cookie, "%d\n", lck->lls_nr);
 316         for (i = 0; i < lck->lls_nr; ++i) {
 317                 struct lov_lock_sub *sub;
 318
 319                 sub = &lck->lls_sub[i];
 320                 (*p)(env, cookie, "    %d %x: ", i, sub->sub_is_enqueued);
 321                 cl_lock_print(env, cookie, p, &sub->sub_lock);
 322         }
 323         return 0;
 324 }
 325
 326 static const struct cl_lock_operations lov_lock_ops = {
 327         .clo_fini      = lov_lock_fini,
 328         .clo_enqueue   = lov_lock_enqueue,
 329         .clo_cancel    = lov_lock_cancel,
 330         .clo_print     = lov_lock_print
 331 };
 332
 333 int lov_lock_init_composite(const struct lu_env *env, struct cl_object *obj,
 334                             struct cl_lock *lock, const struct cl_io *io)
 335 {
 336         struct lov_lock *lck;
 337         int result = 0;
 338
 339         ENTRY;
 340         lck = lov_lock_sub_init(env, io, obj, lock);
 341         if (!IS_ERR(lck))
 342                 cl_lock_slice_add(lock, &lck->lls_cl, obj, &lov_lock_ops);
 343         else
 344                 result = PTR_ERR(lck);
 345         RETURN(result);
 346 }
 347
 348 static void lov_empty_lock_fini(const struct lu_env *env,
 349                                 struct cl_lock_slice *slice)
 350 {
 351         struct lov_lock *lck = cl2lov_lock(slice);
 352
 353         OBD_SLAB_FREE_PTR(lck, lov_lock_kmem);
 354 }
 355
 356 static int lov_empty_lock_print(const struct lu_env *env, void *cookie,
 357                         lu_printer_t p, const struct cl_lock_slice *slice)
 358 {
 359         (*p)(env, cookie, "empty\n");
 360         return 0;
 361 }
 362
 363 /* XXX: more methods will be added later. */
 364 static const struct cl_lock_operations lov_empty_lock_ops = {
 365         .clo_fini  = lov_empty_lock_fini,
 366         .clo_print = lov_empty_lock_print
 367 };
 368
 369 int lov_lock_init_empty(const struct lu_env *env, struct cl_object *obj,
 370                         struct cl_lock *lock, const struct cl_io *io)
 371 {
 372         struct lov_lock *lck;
 373         int result = -ENOMEM;
 374
 375         ENTRY;
 376         OBD_SLAB_ALLOC_PTR_GFP(lck, lov_lock_kmem, GFP_NOFS);
 377         if (lck) {
 378                 cl_lock_slice_add(lock, &lck->lls_cl, obj, &lov_empty_lock_ops);
 379                 result = 0;
 380         }
 381         RETURN(result);
 382 }
 383
 384 /** @} lov */