lustre/llite/statahead.c

   1 /* -*- mode: c; c-basic-offset: 8; indent-tabs-mode: nil; -*-
   2  * vim:expandtab:shiftwidth=8:tabstop=8:
   3  *
   4  * GPL HEADER START
   5  *
   6  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 only,
  10  * as published by the Free Software Foundation.
  11  *
  12  * This program is distributed in the hope that it will be useful, but
  13  * WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * General Public License version 2 for more details (a copy is included
  16  * in the LICENSE file that accompanied this code).
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * version 2 along with this program; If not, see
  20  * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf
  21  *
  22  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
  23  * CA 95054 USA or visit www.sun.com if you need additional information or
  24  * have any questions.
  25  *
  26  * GPL HEADER END
  27  */
  28 /*
  29  * Copyright  2008 Sun Microsystems, Inc. All rights reserved
  30  * Use is subject to license terms.
  31  */
  32 /*
  33  * This file is part of Lustre, http://www.lustre.org/
  34  * Lustre is a trademark of Sun Microsystems, Inc.
  35  */
  36
  37 #include <linux/fs.h>
  38 #include <linux/sched.h>
  39 #include <linux/mm.h>
  40 #include <linux/smp_lock.h>
  41 #include <linux/highmem.h>
  42 #include <linux/pagemap.h>
  43
  44 #define DEBUG_SUBSYSTEM S_LLITE
  45
  46 #include <obd_support.h>
  47 #include <lustre_lite.h>
  48 #include <lustre_dlm.h>
  49 #include <linux/lustre_version.h>
  50 #include "llite_internal.h"
  51
  52 struct ll_sai_entry {
  53         struct list_head        se_list;
  54         unsigned int            se_index;
  55         int                     se_stat;
  56         struct ptlrpc_request  *se_req;
  57         struct md_enqueue_info *se_minfo;
  58 };
  59
  60 enum {
  61         SA_ENTRY_UNSTATED = 0,
  62         SA_ENTRY_STATED
  63 };
  64
  65 struct dentry_operations ll_sai_d_ops = {
  66         .d_release = ll_release,
  67 };
  68
  69 static unsigned int sai_generation = 0;
  70 static spinlock_t sai_generation_lock = SPIN_LOCK_UNLOCKED;
  71
  72 /**
  73  * Check whether first entry was stated already or not.
  74  * No need to hold lli_lock, for:
  75  * (1) it is me that remove entry from the list
  76  * (2) the statahead thread only add new entry to the list
  77  */
  78 static int ll_sai_entry_stated(struct ll_statahead_info *sai)
  79 {
  80         struct ll_sai_entry  *entry;
  81         int                   rc = 0;
  82
  83         if (!list_empty(&sai->sai_entries_stated)) {
  84                 entry = list_entry(sai->sai_entries_stated.next,
  85                                    struct ll_sai_entry, se_list);
  86                 if (entry->se_index == sai->sai_index_next)
  87                         rc = 1;
  88         }
  89         return rc;
  90 }
  91
  92 static inline int sa_received_empty(struct ll_statahead_info *sai)
  93 {
  94         return list_empty(&sai->sai_entries_received);
  95 }
  96
  97 static inline int sa_not_full(struct ll_statahead_info *sai)
  98 {
  99         return sai->sai_index < sai->sai_hit + sai->sai_miss + sai->sai_max;
 100 }
 101
 102 static inline int sa_is_running(struct ll_statahead_info *sai)
 103 {
 104         return !!(sai->sai_thread.t_flags & SVC_RUNNING);
 105 }
 106
 107 static inline int sa_is_stopping(struct ll_statahead_info *sai)
 108 {
 109         return !!(sai->sai_thread.t_flags & SVC_STOPPING);
 110 }
 111
 112 static inline int sa_is_stopped(struct ll_statahead_info *sai)
 113 {
 114         return !!(sai->sai_thread.t_flags & SVC_STOPPED);
 115 }
 116
 117 /**
 118  * (1) hit ratio less than 80%
 119  * or
 120  * (2) consecutive miss more than 8
 121  */
 122 static inline int sa_low_hit(struct ll_statahead_info *sai)
 123 {
 124         return ((sai->sai_hit < 4 * sai->sai_miss && sai->sai_hit > 7) ||
 125                 (sai->sai_consecutive_miss > 8));
 126 }
 127
 128 /**
 129  * process the deleted entry's member and free the entry.
 130  * (1) release intent
 131  * (2) free md_enqueue_info
 132  * (3) drop dentry's ref count
 133  * (4) release request's ref count
 134  */
 135 static void ll_sai_entry_cleanup(struct ll_sai_entry *entry)
 136 {
 137         struct ptlrpc_request  *req = entry->se_req;
 138         struct md_enqueue_info *minfo = entry->se_minfo;
 139         ENTRY;
 140
 141         if (minfo) {
 142                 struct dentry        *dentry = minfo->mi_dentry;
 143                 struct lookup_intent *it = &minfo->mi_it;
 144
 145                 entry->se_minfo = NULL;
 146                 ll_intent_release(it);
 147                 OBD_FREE_PTR(minfo);
 148                 dput(dentry);
 149         }
 150         if (req) {
 151                 entry->se_req = NULL;
 152                 ptlrpc_req_finished(req);
 153         }
 154         OBD_FREE_PTR(entry);
 155
 156         EXIT;
 157 }
 158
 159 static struct ll_statahead_info *ll_sai_alloc(void)
 160 {
 161         struct ll_statahead_info *sai;
 162
 163         OBD_ALLOC_PTR(sai);
 164         if (!sai)
 165                 return NULL;
 166
 167         spin_lock(&sai_generation_lock);
 168         sai->sai_generation = ++sai_generation;
 169         if (unlikely(sai_generation == 0))
 170                 sai->sai_generation = ++sai_generation;
 171         spin_unlock(&sai_generation_lock);
 172         atomic_set(&sai->sai_refcount, 1);
 173         sai->sai_max = LL_SA_RPC_MIN;
 174         cfs_waitq_init(&sai->sai_waitq);
 175         cfs_waitq_init(&sai->sai_thread.t_ctl_waitq);
 176         CFS_INIT_LIST_HEAD(&sai->sai_entries_sent);
 177         CFS_INIT_LIST_HEAD(&sai->sai_entries_received);
 178         CFS_INIT_LIST_HEAD(&sai->sai_entries_stated);
 179         return sai;
 180 }
 181
 182 static inline
 183 struct ll_statahead_info *ll_sai_get(struct ll_statahead_info *sai)
 184 {
 185         LASSERT(sai);
 186         atomic_inc(&sai->sai_refcount);
 187         return sai;
 188 }
 189
 190 static void ll_sai_put(struct ll_statahead_info *sai)
 191 {
 192         struct inode         *inode = sai->sai_inode;
 193         struct ll_inode_info *lli = ll_i2info(inode);
 194         ENTRY;
 195
 196         if (atomic_dec_and_lock(&sai->sai_refcount, &lli->lli_lock)) {
 197                 struct ll_sai_entry *entry, *next;
 198
 199                 lli->lli_sai = NULL;
 200                 spin_unlock(&lli->lli_lock);
 201
 202                 LASSERT(sa_is_stopped(sai));
 203
 204                 if (sai->sai_sent > sai->sai_replied)
 205                         CDEBUG(D_READA,"statahead for dir "DFID" does not "
 206                               "finish: [sent:%u] [replied:%u]\n",
 207                               PFID(&lli->lli_fid),
 208                               sai->sai_sent, sai->sai_replied);
 209
 210                 list_for_each_entry_safe(entry, next, &sai->sai_entries_sent,
 211                                          se_list) {
 212                         list_del(&entry->se_list);
 213                         ll_sai_entry_cleanup(entry);
 214                 }
 215                 list_for_each_entry_safe(entry, next, &sai->sai_entries_received,
 216                                          se_list) {
 217                         list_del(&entry->se_list);
 218                         ll_sai_entry_cleanup(entry);
 219                 }
 220                 list_for_each_entry_safe(entry, next, &sai->sai_entries_stated,
 221                                          se_list) {
 222                         list_del(&entry->se_list);
 223                         ll_sai_entry_cleanup(entry);
 224                 }
 225                 dput(sai->sai_first);
 226                 OBD_FREE_PTR(sai);
 227                 iput(inode);
 228         }
 229         EXIT;
 230 }
 231
 232 /**
 233  * insert it into sai_entries_sent tail when init.
 234  */
 235 static struct ll_sai_entry *
 236 ll_sai_entry_init(struct ll_statahead_info *sai, unsigned int index)
 237 {
 238         struct ll_inode_info *lli = ll_i2info(sai->sai_inode);
 239         struct ll_sai_entry  *entry;
 240         ENTRY;
 241
 242         OBD_ALLOC_PTR(entry);
 243         if (entry == NULL)
 244                 RETURN(ERR_PTR(-ENOMEM));
 245
 246         CDEBUG(D_READA, "alloc sai entry %p index %u\n",
 247                entry, index);
 248         entry->se_index = index;
 249         entry->se_stat  = SA_ENTRY_UNSTATED;
 250
 251         spin_lock(&lli->lli_lock);
 252         list_add_tail(&entry->se_list, &sai->sai_entries_sent);
 253         spin_unlock(&lli->lli_lock);
 254
 255         RETURN(entry);
 256 }
 257
 258 /**
 259  * delete it from sai_entries_stated head when fini, it need not
 260  * to process entry's member.
 261  */
 262 static void ll_sai_entry_fini(struct ll_statahead_info *sai)
 263 {
 264         struct ll_inode_info *lli = ll_i2info(sai->sai_inode);
 265         struct ll_sai_entry  *entry;
 266         ENTRY;
 267
 268         spin_lock(&lli->lli_lock);
 269         sai->sai_index_next++;
 270         if (likely(!list_empty(&sai->sai_entries_stated))) {
 271                 entry = list_entry(sai->sai_entries_stated.next,
 272                                    struct ll_sai_entry, se_list);
 273                 if (entry->se_index < sai->sai_index_next) {
 274                         list_del(&entry->se_list);
 275                         OBD_FREE_PTR(entry);
 276                 }
 277         } else
 278                 LASSERT(sa_is_stopped(sai));
 279         spin_unlock(&lli->lli_lock);
 280
 281         EXIT;
 282 }
 283
 284 /**
 285  * inside lli_lock.
 286  * \retval NULL : can not find the entry in sai_entries_sent with the index
 287  * \retval entry: find the entry in sai_entries_sent with the index
 288  */
 289 static struct ll_sai_entry *
 290 ll_sai_entry_set(struct ll_statahead_info *sai, unsigned int index, int stat,
 291                  struct ptlrpc_request *req, struct md_enqueue_info *minfo)
 292 {
 293         struct ll_sai_entry *entry;
 294         ENTRY;
 295
 296         if (!list_empty(&sai->sai_entries_sent)) {
 297                 list_for_each_entry(entry, &sai->sai_entries_sent,
 298                                     se_list) {
 299                         if (entry->se_index == index) {
 300                                 entry->se_stat = stat;
 301                                 entry->se_req = ptlrpc_request_addref(req);
 302                                 entry->se_minfo = minfo;
 303                                 RETURN(entry);
 304                         } else if (entry->se_index > index)
 305                                 RETURN(NULL);
 306                 }
 307         }
 308         RETURN(NULL);
 309 }
 310
 311 /**
 312  * inside lli_lock.
 313  * Move entry to sai_entries_received and
 314  * insert it into sai_entries_received tail.
 315  */
 316 static inline void
 317 ll_sai_entry_to_received(struct ll_statahead_info *sai, struct ll_sai_entry *entry)
 318 {
 319         if (!list_empty(&entry->se_list))
 320                 list_del_init(&entry->se_list);
 321         list_add_tail(&entry->se_list, &sai->sai_entries_received);
 322 }
 323
 324 /**
 325  * Move entry to sai_entries_stated and
 326  * sort with the index.
 327  */
 328 static int
 329 ll_sai_entry_to_stated(struct ll_statahead_info *sai, struct ll_sai_entry *entry)
 330 {
 331         struct ll_inode_info *lli = ll_i2info(sai->sai_inode);
 332         struct ll_sai_entry  *se;
 333         ENTRY;
 334
 335         spin_lock(&lli->lli_lock);
 336         if (!list_empty(&entry->se_list))
 337                 list_del_init(&entry->se_list);
 338
 339         if (unlikely(entry->se_index < sai->sai_index_next)) {
 340                 spin_unlock(&lli->lli_lock);
 341                 ll_sai_entry_cleanup(entry);
 342                 RETURN(0);
 343         }
 344
 345         list_for_each_entry_reverse(se, &sai->sai_entries_stated, se_list) {
 346                 if (se->se_index < entry->se_index) {
 347                         list_add(&entry->se_list, &se->se_list);
 348                         spin_unlock(&lli->lli_lock);
 349                         RETURN(1);
 350                 }
 351         }
 352
 353         /*
 354          * I am the first entry.
 355          */
 356         list_add(&entry->se_list, &sai->sai_entries_stated);
 357         spin_unlock(&lli->lli_lock);
 358         RETURN(1);
 359 }
 360
 361 /**
 362  * finish lookup/revalidate.
 363  */
 364 static int do_statahead_interpret(struct ll_statahead_info *sai)
 365 {
 366         struct ll_inode_info   *lli = ll_i2info(sai->sai_inode);
 367         struct ll_sai_entry    *entry;
 368         struct ptlrpc_request  *req;
 369         struct md_enqueue_info *minfo;
 370         struct dentry          *dentry;
 371         struct lookup_intent   *it;
 372         int                     rc = 0;
 373         ENTRY;
 374
 375         spin_lock(&lli->lli_lock);
 376         LASSERT(!sa_received_empty(sai));
 377         entry = list_entry(sai->sai_entries_received.next, struct ll_sai_entry,
 378                            se_list);
 379         list_del_init(&entry->se_list);
 380         spin_unlock(&lli->lli_lock);
 381
 382         if (unlikely(entry->se_index < sai->sai_index_next)) {
 383                 ll_sai_entry_cleanup(entry);
 384                 RETURN(0);
 385         }
 386
 387         req = entry->se_req;
 388         minfo = entry->se_minfo;
 389         dentry = minfo->mi_dentry;
 390         it = &minfo->mi_it;
 391
 392         if (entry->se_stat != SA_ENTRY_STATED)
 393                 GOTO(out, rc = entry->se_stat);
 394
 395         if (dentry->d_inode == NULL) {
 396                 /*
 397                  * lookup.
 398                  */
 399                 struct dentry    *save = dentry;
 400                 struct it_cb_data icbd = {
 401                         .icbd_parent   = dentry->d_parent->d_inode,
 402                         .icbd_childp   = &dentry
 403                 };
 404
 405                 LASSERT(fid_is_zero(&minfo->mi_data.op_fid2));
 406
 407                 rc = ll_lookup_it_finish(req, it, &icbd);
 408                 if (!rc)
 409                         /*
 410                          * Here dentry->d_inode might be NULL,
 411                          * because the entry may have been removed before
 412                          * we start doing stat ahead.
 413                          */
 414                         ll_lookup_finish_locks(it, dentry);
 415
 416                 if (dentry != save) {
 417                         minfo->mi_dentry = dentry;
 418                         dput(save);
 419                 }
 420         } else {
 421                 /*
 422                  * revalidate.
 423                  */
 424                 struct mdt_body *body;
 425
 426                 body = lustre_msg_buf(req->rq_repmsg, DLM_REPLY_REC_OFF,
 427                                       sizeof(*body));
 428                 if (!lu_fid_eq(&minfo->mi_data.op_fid2, &body->fid1)) {
 429                         ll_unhash_aliases(dentry->d_inode);
 430                         GOTO(out, rc = -EAGAIN);
 431                 }
 432
 433                 rc = ll_revalidate_it_finish(req, it, dentry);
 434                 if (rc) {
 435                         ll_unhash_aliases(dentry->d_inode);
 436                         GOTO(out, rc);
 437                 }
 438
 439                 spin_lock(&dcache_lock);
 440                 lock_dentry(dentry);
 441                 __d_drop(dentry);
 442 #ifdef DCACHE_LUSTRE_INVALID
 443                 dentry->d_flags &= ~DCACHE_LUSTRE_INVALID;
 444 #endif
 445                 unlock_dentry(dentry);
 446                 d_rehash_cond(dentry, 0);
 447                 spin_unlock(&dcache_lock);
 448
 449                 ll_lookup_finish_locks(it, dentry);
 450         }
 451         EXIT;
 452
 453 out:
 454         if (likely(ll_sai_entry_to_stated(sai, entry))) {
 455                 entry->se_minfo = NULL;
 456                 entry->se_req = NULL;
 457                 cfs_waitq_signal(&sai->sai_waitq);
 458                 ll_intent_release(it);
 459                 OBD_FREE_PTR(minfo);
 460                 dput(dentry);
 461                 ptlrpc_req_finished(req);
 462         }
 463         return rc;
 464 }
 465
 466 static int ll_statahead_interpret(struct ptlrpc_request *req,
 467                                   struct md_enqueue_info *minfo,
 468                                   int rc)
 469 {
 470         struct dentry            *dentry = minfo->mi_dentry;
 471         struct lookup_intent     *it = &minfo->mi_it;
 472         struct inode             *dir = dentry->d_parent->d_inode;
 473         struct ll_inode_info     *lli = ll_i2info(dir);
 474         struct ll_statahead_info *sai;
 475         struct ll_sai_entry      *entry;
 476         ENTRY;
 477
 478         CDEBUG(D_READA, "interpret statahead %.*s rc %d\n",
 479                dentry->d_name.len, dentry->d_name.name, rc);
 480
 481         spin_lock(&lli->lli_lock);
 482         if (unlikely(lli->lli_sai == NULL ||
 483             lli->lli_sai->sai_generation != minfo->mi_generation)) {
 484                 spin_unlock(&lli->lli_lock);
 485                 ll_intent_release(it);
 486                 dput(dentry);
 487                 OBD_FREE_PTR(minfo);
 488                 RETURN(-ESTALE);
 489         } else {
 490                 sai = lli->lli_sai;
 491                 if (rc || dir == NULL)
 492                         rc = -ESTALE;
 493
 494                 entry = ll_sai_entry_set(sai,
 495                                          (unsigned int)(long)minfo->mi_cbdata,
 496                                          rc ? SA_ENTRY_UNSTATED :
 497                                          SA_ENTRY_STATED, req, minfo);
 498                 LASSERT(entry != NULL);
 499                 if (likely(sa_is_running(sai))) {
 500                         ll_sai_entry_to_received(sai, entry);
 501                         sai->sai_replied++;
 502                         spin_unlock(&lli->lli_lock);
 503                         cfs_waitq_signal(&sai->sai_thread.t_ctl_waitq);
 504                 } else {
 505                         if (!list_empty(&entry->se_list))
 506                                 list_del_init(&entry->se_list);
 507                         sai->sai_replied++;
 508                         spin_unlock(&lli->lli_lock);
 509                         ll_sai_entry_cleanup(entry);
 510                 }
 511                 RETURN(rc);
 512         }
 513 }
 514
 515 static void sa_args_fini(struct md_enqueue_info *minfo,
 516                          struct ldlm_enqueue_info *einfo)
 517 {
 518         LASSERT(minfo && einfo);
 519         capa_put(minfo->mi_data.op_capa1);
 520         capa_put(minfo->mi_data.op_capa2);
 521         OBD_FREE_PTR(minfo);
 522         OBD_FREE_PTR(einfo);
 523 }
 524
 525 /**
 526  * There is race condition between "capa_put" and "ll_statahead_interpret" for
 527  * accessing "op_data.op_capa[1,2]" as following:
 528  * "capa_put" releases "op_data.op_capa[1,2]"'s reference count after calling
 529  * "md_intent_getattr_async". But "ll_statahead_interpret" maybe run first, and
 530  * fill "op_data.op_capa[1,2]" as POISON, then cause "capa_put" access invalid
 531  * "ocapa". So here reserve "op_data.op_capa[1,2]" in "pcapa" before calling
 532  * "md_intent_getattr_async".
 533  */
 534 static int sa_args_init(struct inode *dir, struct dentry *dentry,
 535                         struct md_enqueue_info **pmi,
 536                         struct ldlm_enqueue_info **pei,
 537                         struct obd_capa **pcapa)
 538 {
 539         struct ll_inode_info     *lli = ll_i2info(dir);
 540         struct md_enqueue_info   *minfo;
 541         struct ldlm_enqueue_info *einfo;
 542         struct md_op_data        *op_data;
 543
 544         OBD_ALLOC_PTR(einfo);
 545         if (einfo == NULL)
 546                 return -ENOMEM;
 547
 548         OBD_ALLOC_PTR(minfo);
 549         if (minfo == NULL) {
 550                 OBD_FREE_PTR(einfo);
 551                 return -ENOMEM;
 552         }
 553
 554         op_data = ll_prep_md_op_data(&minfo->mi_data, dir, dentry->d_inode,
 555                                      dentry->d_name.name, dentry->d_name.len,
 556                                      0, LUSTRE_OPC_ANY, NULL);
 557         if (IS_ERR(op_data)) {
 558                 OBD_FREE_PTR(einfo);
 559                 OBD_FREE_PTR(minfo);
 560                 return PTR_ERR(op_data);
 561         }
 562
 563         minfo->mi_it.it_op = IT_GETATTR;
 564         minfo->mi_dentry = dentry;
 565         minfo->mi_cb = ll_statahead_interpret;
 566         minfo->mi_generation = lli->lli_sai->sai_generation;
 567         minfo->mi_cbdata = (void *)(long)lli->lli_sai->sai_index;
 568
 569         einfo->ei_type   = LDLM_IBITS;
 570         einfo->ei_mode   = it_to_lock_mode(&minfo->mi_it);
 571         einfo->ei_cb_bl  = ll_md_blocking_ast;
 572         einfo->ei_cb_cp  = ldlm_completion_ast;
 573         einfo->ei_cb_gl  = NULL;
 574         einfo->ei_cbdata = NULL;
 575
 576         *pmi = minfo;
 577         *pei = einfo;
 578         pcapa[0] = op_data->op_capa1;
 579         pcapa[1] = op_data->op_capa2;
 580
 581         return 0;
 582 }
 583
 584 /**
 585  * similar to ll_lookup_it().
 586  */
 587 static int do_sa_lookup(struct inode *dir, struct dentry *dentry)
 588 {
 589         struct md_enqueue_info   *minfo;
 590         struct ldlm_enqueue_info *einfo;
 591         struct obd_capa          *capas[2];
 592         int                       rc;
 593         ENTRY;
 594
 595         rc = sa_args_init(dir, dentry, &minfo, &einfo, capas);
 596         if (rc)
 597                 RETURN(rc);
 598
 599         rc = md_intent_getattr_async(ll_i2mdexp(dir), minfo, einfo);
 600         if (!rc) {
 601                 capa_put(capas[0]);
 602                 capa_put(capas[1]);
 603         } else {
 604                 sa_args_fini(minfo, einfo);
 605         }
 606
 607         RETURN(rc);
 608 }
 609
 610 /**
 611  * similar to ll_revalidate_it().
 612  * \retval      1 -- dentry valid
 613  * \retval      0 -- will send stat-ahead request
 614  * \retval others -- prepare stat-ahead request failed
 615  */
 616 static int do_sa_revalidate(struct dentry *dentry)
 617 {
 618         struct inode             *inode = dentry->d_inode;
 619         struct inode             *dir = dentry->d_parent->d_inode;
 620         struct lookup_intent      it = { .it_op = IT_GETATTR };
 621         struct md_enqueue_info   *minfo;
 622         struct ldlm_enqueue_info *einfo;
 623         struct obd_capa          *capas[2];
 624         int rc;
 625         ENTRY;
 626
 627         if (inode == NULL)
 628                 RETURN(1);
 629
 630         if (d_mountpoint(dentry))
 631                 RETURN(1);
 632
 633         if (dentry == dentry->d_sb->s_root)
 634                 RETURN(1);
 635
 636         rc = md_revalidate_lock(ll_i2mdexp(dir), &it, ll_inode2fid(inode));
 637         if (rc == 1) {
 638                 ll_intent_release(&it);
 639                 RETURN(1);
 640         }
 641
 642         rc = sa_args_init(dir, dentry, &minfo, &einfo, capas);
 643         if (rc)
 644                 RETURN(rc);
 645
 646         rc = md_intent_getattr_async(ll_i2mdexp(dir), minfo, einfo);
 647         if (!rc) {
 648                 capa_put(capas[0]);
 649                 capa_put(capas[1]);
 650         } else {
 651                 sa_args_fini(minfo, einfo);
 652         }
 653
 654         RETURN(rc);
 655 }
 656
 657 static inline void ll_name2qstr(struct qstr *this, const char *name, int namelen)
 658 {
 659         unsigned long hash = init_name_hash();
 660         unsigned int  c;
 661
 662         this->name = name;
 663         this->len  = namelen;
 664         for (; namelen > 0; namelen--, name++) {
 665                 c = *(const unsigned char *)name;
 666                 hash = partial_name_hash(c, hash);
 667         }
 668         this->hash = end_name_hash(hash);
 669 }
 670
 671 static int ll_statahead_one(struct dentry *parent, const char* entry_name,
 672                             int entry_name_len)
 673 {
 674         struct inode             *dir = parent->d_inode;
 675         struct ll_inode_info     *lli = ll_i2info(dir);
 676         struct ll_statahead_info *sai = lli->lli_sai;
 677         struct qstr               name;
 678         struct dentry            *dentry;
 679         struct ll_sai_entry      *se;
 680         int                       rc;
 681         ENTRY;
 682
 683 #ifdef DCACHE_LUSTRE_INVALID
 684         if (parent->d_flags & DCACHE_LUSTRE_INVALID) {
 685 #else
 686         if (d_unhashed(parent)) {
 687 #endif
 688                 CDEBUG(D_READA, "parent dentry@%p %.*s is "
 689                        "invalid, skip statahead\n",
 690                        parent, parent->d_name.len, parent->d_name.name);
 691                 RETURN(-EINVAL);
 692         }
 693
 694         se = ll_sai_entry_init(sai, sai->sai_index);
 695         if (IS_ERR(se))
 696                 RETURN(PTR_ERR(se));
 697
 698         ll_name2qstr(&name, entry_name, entry_name_len);
 699         dentry = d_lookup(parent, &name);
 700         if (!dentry) {
 701                 dentry = d_alloc(parent, &name);
 702                 if (dentry) {
 703                         rc = do_sa_lookup(dir, dentry);
 704                         if (rc)
 705                                 dput(dentry);
 706                 } else {
 707                         GOTO(out, rc = -ENOMEM);
 708                 }
 709         } else {
 710                 rc = do_sa_revalidate(dentry);
 711                 if (rc)
 712                         dput(dentry);
 713         }
 714
 715         EXIT;
 716
 717 out:
 718         if (rc) {
 719                 CDEBUG(D_READA, "set sai entry %p index %u stat %d rc %d\n",
 720                        se, se->se_index, se->se_stat, rc);
 721                 se->se_stat = rc;
 722                 if (ll_sai_entry_to_stated(sai, se))
 723                         cfs_waitq_signal(&sai->sai_waitq);
 724         } else {
 725                 sai->sai_sent++;
 726         }
 727
 728         sai->sai_index++;
 729         return rc;
 730 }
 731
 732 struct ll_sa_thread_args {
 733         struct dentry   *sta_parent;
 734         pid_t            sta_pid;
 735 };
 736
 737 static int ll_statahead_thread(void *arg)
 738 {
 739         struct ll_sa_thread_args *sta = arg;
 740         struct dentry            *parent = dget(sta->sta_parent);
 741         struct inode             *dir = parent->d_inode;
 742         struct ll_inode_info     *lli = ll_i2info(dir);
 743         struct ll_sb_info        *sbi = ll_i2sbi(dir);
 744         struct ll_statahead_info *sai = ll_sai_get(lli->lli_sai);
 745         struct ptlrpc_thread     *thread = &sai->sai_thread;
 746         struct page              *page;
 747         __u64                     pos = 0;
 748         int                       first = 0;
 749         int                       rc = 0;
 750         struct ll_dir_chain       chain;
 751         ENTRY;
 752
 753         {
 754                 char pname[16];
 755                 snprintf(pname, 15, "ll_sa_%u", sta->sta_pid);
 756                 cfs_daemonize(pname);
 757         }
 758
 759         sbi->ll_sa_total++;
 760         spin_lock(&lli->lli_lock);
 761         thread->t_flags = SVC_RUNNING;
 762         spin_unlock(&lli->lli_lock);
 763         cfs_waitq_signal(&thread->t_ctl_waitq);
 764         CDEBUG(D_READA, "start doing statahead for %s\n", parent->d_name.name);
 765
 766         ll_dir_chain_init(&chain);
 767         page = ll_get_dir_page(dir, pos, 0, &chain);
 768
 769         while (1) {
 770                 struct l_wait_info lwi = { 0 };
 771                 struct lu_dirpage *dp;
 772                 struct lu_dirent  *ent;
 773
 774                 if (IS_ERR(page)) {
 775                         rc = PTR_ERR(page);
 776                         CERROR("error reading dir "DFID" at "LPU64"/%u: rc %d\n",
 777                                PFID(ll_inode2fid(dir)), pos,
 778                                sai->sai_index, rc);
 779                         break;
 780                 }
 781
 782                 dp = page_address(page);
 783                 for (ent = lu_dirent_start(dp); ent != NULL;
 784                      ent = lu_dirent_next(ent)) {
 785                         char *name = ent->lde_name;
 786                         int namelen = le16_to_cpu(ent->lde_namelen);
 787
 788                         if (namelen == 0)
 789                                 /*
 790                                  * Skip dummy record.
 791                                  */
 792                                 continue;
 793
 794                         if (name[0] == '.') {
 795                                 if (namelen == 1) {
 796                                         /*
 797                                          * skip "."
 798                                          */
 799                                         continue;
 800                                 } else if (name[1] == '.' && namelen == 2) {
 801                                         /*
 802                                          * skip ".."
 803                                          */
 804                                         continue;
 805                                 } else if (!sai->sai_ls_all) {
 806                                         /*
 807                                          * skip hidden files.
 808                                          */
 809                                         sai->sai_skip_hidden++;
 810                                         continue;
 811                                 }
 812                         }
 813
 814                         /*
 815                          * don't stat-ahead first entry.
 816                          */
 817                         if (unlikely(!first)) {
 818                                 first++;
 819                                 continue;
 820                         }
 821
 822 keep_de:
 823                         l_wait_event(thread->t_ctl_waitq,
 824                                      !sa_is_running(sai) || sa_not_full(sai) ||
 825                                      !sa_received_empty(sai),
 826                                      &lwi);
 827
 828                         while (!sa_received_empty(sai) && sa_is_running(sai))
 829                                 do_statahead_interpret(sai);
 830
 831                         if (unlikely(!sa_is_running(sai))) {
 832                                 ll_put_page(page);
 833                                 GOTO(out, rc);
 834                         }
 835
 836                         if (!sa_not_full(sai))
 837                                 /*
 838                                  * do not skip the current de.
 839                                  */
 840                                 goto keep_de;
 841
 842                         rc = ll_statahead_one(parent, name, namelen);
 843                         if (rc < 0) {
 844                                 ll_put_page(page);
 845                                 GOTO(out, rc);
 846                         }
 847                 }
 848                 pos = le64_to_cpu(dp->ldp_hash_end);
 849                 ll_put_page(page);
 850                 if (pos == DIR_END_OFF) {
 851                         /*
 852                          * End of directory reached.
 853                          */
 854                         while (1) {
 855                                 l_wait_event(thread->t_ctl_waitq,
 856                                              !sa_is_running(sai) ||
 857                                              !sa_received_empty(sai) ||
 858                                              sai->sai_sent == sai->sai_replied,
 859                                              &lwi);
 860                                 if (!sa_received_empty(sai) &&
 861                                     sa_is_running(sai))
 862                                         do_statahead_interpret(sai);
 863                                 else
 864                                         GOTO(out, rc);
 865                         }
 866                 } else if (1) {
 867                         /*
 868                          * chain is exhausted.
 869                          * Normal case: continue to the next page.
 870                          */
 871                         page = ll_get_dir_page(dir, pos, 1, &chain);
 872                 } else {
 873                         /*
 874                          * go into overflow page.
 875                          */
 876                 }
 877         }
 878         EXIT;
 879
 880 out:
 881         ll_dir_chain_fini(&chain);
 882         spin_lock(&lli->lli_lock);
 883         thread->t_flags = SVC_STOPPED;
 884         spin_unlock(&lli->lli_lock);
 885         cfs_waitq_signal(&sai->sai_waitq);
 886         cfs_waitq_signal(&thread->t_ctl_waitq);
 887         ll_sai_put(sai);
 888         dput(parent);
 889         CDEBUG(D_READA, "statahead thread stopped, pid %d\n",
 890                cfs_curproc_pid());
 891         return rc;
 892 }
 893
 894 /**
 895  * called in ll_file_release().
 896  */
 897 void ll_stop_statahead(struct inode *inode, void *key)
 898 {
 899         struct ll_inode_info *lli = ll_i2info(inode);
 900         struct ptlrpc_thread *thread;
 901
 902         spin_lock(&lli->lli_lock);
 903         if (lli->lli_opendir_pid == 0 ||
 904             unlikely(lli->lli_opendir_key != key)) {
 905                 spin_unlock(&lli->lli_lock);
 906                 return;
 907         }
 908
 909         lli->lli_opendir_key = NULL;
 910         lli->lli_opendir_pid = 0;
 911
 912         if (lli->lli_sai) {
 913                 struct l_wait_info lwi = { 0 };
 914
 915                 thread = &lli->lli_sai->sai_thread;
 916                 if (!sa_is_stopped(lli->lli_sai)) {
 917                         thread->t_flags = SVC_STOPPING;
 918                         spin_unlock(&lli->lli_lock);
 919                         cfs_waitq_signal(&thread->t_ctl_waitq);
 920
 921                         CDEBUG(D_READA, "stopping statahead thread, pid %d\n",
 922                                cfs_curproc_pid());
 923                         l_wait_event(thread->t_ctl_waitq,
 924                                      sa_is_stopped(lli->lli_sai),
 925                                      &lwi);
 926                 } else {
 927                         spin_unlock(&lli->lli_lock);
 928                 }
 929
 930                 /*
 931                  * Put the ref which was held when first statahead_enter.
 932                  * It maybe not the last ref for some statahead requests
 933                  * maybe inflight.
 934                  */
 935                 ll_sai_put(lli->lli_sai);
 936                 return;
 937         }
 938         spin_unlock(&lli->lli_lock);
 939 }
 940
 941 enum {
 942         /**
 943          * not first dirent, or is "."
 944          */
 945         LS_NONE_FIRST_DE = 0,
 946         /**
 947          * the first non-hidden dirent
 948          */
 949         LS_FIRST_DE,
 950         /**
 951          * the first hidden dirent, that is ".xxx
 952          */
 953         LS_FIRST_DOT_DE
 954 };
 955
 956 static int is_first_dirent(struct inode *dir, struct dentry *dentry)
 957 {
 958         struct ll_dir_chain chain;
 959         struct qstr        *target = &dentry->d_name;
 960         struct page        *page;
 961         __u64               pos = 0;
 962         int                 dot_de;
 963         int                 rc = LS_NONE_FIRST_DE;
 964         ENTRY;
 965
 966         ll_dir_chain_init(&chain);
 967         page = ll_get_dir_page(dir, pos, 0, &chain);
 968
 969         while (1) {
 970                 struct lu_dirpage *dp;
 971                 struct lu_dirent  *ent;
 972
 973                 if (IS_ERR(page)) {
 974                         rc = PTR_ERR(page);
 975                         CERROR("error reading dir "DFID" at "LPU64": rc %d\n",
 976                                PFID(ll_inode2fid(dir)), pos, rc);
 977                         break;
 978                 }
 979
 980                 dp = page_address(page);
 981                 for (ent = lu_dirent_start(dp); ent != NULL;
 982                      ent = lu_dirent_next(ent)) {
 983                         char *name = ent->lde_name;
 984                         int namelen = le16_to_cpu(ent->lde_namelen);
 985
 986                         if (namelen == 0)
 987                                 /*
 988                                  * skip dummy record.
 989                                  */
 990                                 continue;
 991
 992                         if (name[0] == '.') {
 993                                 if (namelen == 1)
 994                                         /*
 995                                          * skip "."
 996                                          */
 997                                         continue;
 998                                 else if (name[1] == '.' && namelen == 2)
 999                                         /*
1000                                          * skip ".."
1001                                          */
1002                                         continue;
1003                                 else
1004                                         dot_de = 1;
1005                         } else {
1006                                 dot_de = 0;
1007                         }
1008
1009                         if (dot_de && target->name[0] != '.') {
1010                                 CDEBUG(D_READA, "%.*s skip hidden file %.*s\n",
1011                                        target->len, target->name,
1012                                        namelen, name);
1013                                 continue;
1014                         }
1015
1016                         if (target->len == namelen &&
1017                             !strncmp(target->name, name, target->len))
1018                                 rc = LS_FIRST_DE + dot_de;
1019                         else
1020                                 rc = LS_NONE_FIRST_DE;
1021                         ll_put_page(page);
1022                         GOTO(out, rc);
1023                 }
1024                 pos = le64_to_cpu(dp->ldp_hash_end);
1025                 ll_put_page(page);
1026                 if (pos == DIR_END_OFF) {
1027                         /*
1028                          * End of directory reached.
1029                          */
1030                         break;
1031                 } else if (1) {
1032                         /*
1033                          * chain is exhausted
1034                          * Normal case: continue to the next page.
1035                          */
1036                         page = ll_get_dir_page(dir, pos, 1, &chain);
1037                 } else {
1038                         /*
1039                          * go into overflow page.
1040                          */
1041                 }
1042         }
1043         EXIT;
1044
1045 out:
1046         ll_dir_chain_fini(&chain);
1047         return rc;
1048 }
1049
1050 /**
1051  * Start statahead thread if this is the first dir entry.
1052  * Otherwise if a thread is started already, wait it until it is ahead of me.
1053  * \retval 0       -- stat ahead thread process such dentry, for lookup, it miss
1054  * \retval 1       -- stat ahead thread process such dentry, for lookup, it hit
1055  * \retval -EEXIST -- stat ahead thread started, and this is the first dentry
1056  * \retval -EBADFD -- statahead thread exit and not dentry available
1057  * \retval others  -- error
1058  */
1059 int do_statahead_enter(struct inode *dir, struct dentry **dentryp, int lookup)
1060 {
1061         struct ll_sb_info        *sbi = ll_i2sbi(dir);
1062         struct ll_inode_info     *lli = ll_i2info(dir);
1063         struct ll_statahead_info *sai = lli->lli_sai;
1064         struct ll_sa_thread_args  sta;
1065         struct l_wait_info        lwi = { 0 };
1066         int                       rc;
1067         ENTRY;
1068
1069         LASSERT(lli->lli_opendir_pid == cfs_curproc_pid());
1070
1071         if (sai) {
1072                 if (unlikely(sa_is_stopped(sai) &&
1073                              list_empty(&sai->sai_entries_stated)))
1074                         RETURN(-EBADFD);
1075
1076                 /*
1077                  * skip the first dentry.
1078                  */
1079                 if (unlikely((*dentryp)->d_name.len ==
1080                              sai->sai_first->d_name.len &&
1081                              !strncmp((*dentryp)->d_name.name,
1082                                       sai->sai_first->d_name.name,
1083                                       sai->sai_first->d_name.len)))
1084                         RETURN(-EEXIST);
1085
1086                 if ((*dentryp)->d_name.name[0] == '.') {
1087                         if (likely(sai->sai_ls_all ||
1088                             sai->sai_miss_hidden >= sai->sai_skip_hidden)) {
1089                                 /*
1090                                  * Hidden dentry is the first one, or statahead
1091                                  * thread does not skip so many hidden dentries
1092                                  * before "sai_ls_all" enabled as below.
1093                                  */
1094                         } else {
1095                                 if (!sai->sai_ls_all)
1096                                         /*
1097                                          * It maybe because hidden dentry is not
1098                                          * the first one, "sai_ls_all" was not
1099                                          * set, then "ls -al" missed. Enable
1100                                          * "sai_ls_all" for such case.
1101                                          */
1102                                         sai->sai_ls_all = 1;
1103
1104                                 /*
1105                                  * Such "getattr" has been skipped before
1106                                  * "sai_ls_all" enabled as above.
1107                                  */
1108                                 sai->sai_miss_hidden++;
1109                                 RETURN(-ENOENT);
1110                         }
1111                 }
1112
1113                 if (ll_sai_entry_stated(sai)) {
1114                         sbi->ll_sa_cached++;
1115                 } else {
1116                         sbi->ll_sa_blocked++;
1117                         /*
1118                          * thread started already, avoid double-stat.
1119                          */
1120                         l_wait_event(sai->sai_waitq,
1121                                      ll_sai_entry_stated(sai) || sa_is_stopped(sai),
1122                                      &lwi);
1123                 }
1124
1125                 if (lookup) {
1126                         struct dentry *result;
1127
1128                         result = d_lookup((*dentryp)->d_parent,
1129                                           &(*dentryp)->d_name);
1130                         if (result) {
1131                                 LASSERT(result != *dentryp);
1132                                 /* BUG 16303: do not drop reference count for
1133                                  * "*dentryp", VFS will do that by itself. */
1134                                 *dentryp = result;
1135                                 RETURN(1);
1136                         }
1137                 }
1138                 /*
1139                  * do nothing for revalidate.
1140                  */
1141                 RETURN(0);
1142         }
1143
1144          /*
1145           * I am the "lli_opendir_pid" owner, only me can set "lli_sai".
1146           */
1147         LASSERT(lli->lli_sai == NULL);
1148
1149         rc = is_first_dirent(dir, *dentryp);
1150         if (rc == LS_NONE_FIRST_DE) {
1151                 /*
1152                  * It is not "ls -{a}l" operation, no need statahead for it.
1153                  */
1154                 spin_lock(&lli->lli_lock);
1155                 lli->lli_opendir_key = NULL;
1156                 lli->lli_opendir_pid = 0;
1157                 spin_unlock(&lli->lli_lock);
1158                 RETURN(-EBADF);
1159         }
1160
1161         sai = ll_sai_alloc();
1162         if (sai == NULL)
1163                 RETURN(-ENOMEM);
1164
1165         sai->sai_inode  = igrab(dir);
1166         sai->sai_first = dget(*dentryp);
1167         sai->sai_ls_all = (rc == LS_FIRST_DOT_DE);
1168
1169         sta.sta_parent = (*dentryp)->d_parent;
1170         sta.sta_pid    = cfs_curproc_pid();
1171
1172         lli->lli_sai = sai;
1173         rc = cfs_kernel_thread(ll_statahead_thread, &sta, 0);
1174         if (rc < 0) {
1175                 CERROR("can't start ll_sa thread, rc: %d\n", rc);
1176                 sai->sai_thread.t_flags = SVC_STOPPED;
1177                 ll_sai_put(sai);
1178                 LASSERT(lli->lli_sai == NULL);
1179                 RETURN(rc);
1180         }
1181
1182         l_wait_event(sai->sai_thread.t_ctl_waitq,
1183                      sa_is_running(sai) || sa_is_stopped(sai),
1184                      &lwi);
1185
1186         /*
1187          * We don't stat-ahead for the first dirent since we are already in
1188          * lookup, and -EEXIST also indicates that this is the first dirent.
1189          */
1190         RETURN(-EEXIST);
1191 }
1192
1193 /**
1194  * update hit/miss count.
1195  */
1196 int ll_statahead_exit(struct dentry *dentry, int result)
1197 {
1198         struct dentry         *parent = dentry->d_parent;
1199         struct ll_inode_info  *lli = ll_i2info(parent->d_inode);
1200         struct ll_sb_info     *sbi = ll_i2sbi(parent->d_inode);
1201         struct ll_dentry_data *ldd = ll_d2d(dentry);
1202         ENTRY;
1203
1204         if (lli->lli_opendir_pid != cfs_curproc_pid())
1205                 RETURN(-EBADFD);
1206
1207         if (lli->lli_sai) {
1208                 struct ll_statahead_info *sai = lli->lli_sai;
1209
1210                 if (result >= 1) {
1211                         sbi->ll_sa_hit++;
1212                         sai->sai_hit++;
1213                         sai->sai_consecutive_miss = 0;
1214                         sai->sai_max = min(2 * sai->sai_max, sbi->ll_sa_max);
1215                 } else {
1216                         sbi->ll_sa_miss++;
1217                         sai->sai_miss++;
1218                         sai->sai_consecutive_miss++;
1219                         if (sa_low_hit(sai) && sa_is_running(sai)) {
1220                                 sbi->ll_sa_wrong++;
1221                                 CDEBUG(D_READA, "statahead for dir %.*s hit "
1222                                        "ratio too low: hit/miss %u/%u, "
1223                                        "sent/replied %u/%u. stopping statahead "
1224                                        "thread: pid %d\n",
1225                                        parent->d_name.len, parent->d_name.name,
1226                                        sai->sai_hit, sai->sai_miss,
1227                                        sai->sai_sent, sai->sai_replied,
1228                                        cfs_curproc_pid());
1229                                 spin_lock(&lli->lli_lock);
1230                                 if (!sa_is_stopped(sai))
1231                                         sai->sai_thread.t_flags = SVC_STOPPING;
1232                                 spin_unlock(&lli->lli_lock);
1233                         }
1234                 }
1235
1236                 if (!sa_is_stopped(sai))
1237                         cfs_waitq_signal(&sai->sai_thread.t_ctl_waitq);
1238                 ll_sai_entry_fini(sai);
1239
1240                 if (unlikely(ldd == NULL)) {
1241                         ll_set_dd(dentry);
1242                         ldd = ll_d2d(dentry);
1243                         if (ldd != NULL && dentry->d_op == NULL) {
1244                                 lock_dentry(dentry);
1245                                 dentry->d_op = dentry->d_op ? : &ll_sai_d_ops;
1246                                 unlock_dentry(dentry);
1247                         }
1248                 }
1249
1250                 if (likely(ldd != NULL))
1251                         ldd->lld_sa_generation = sai->sai_generation;
1252                 else
1253                         RETURN(-ENOMEM);
1254         }
1255         RETURN(0);
1256 }