1 /* -*- mode: c; c-basic-offset: 8; indent-tabs-mode: nil; -*-
2 * vim:expandtab:shiftwidth=8:tabstop=8:
6 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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.
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).
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
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
29 * Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
30 * Use is subject to license terms.
33 * This file is part of Lustre, http://www.lustre.org/
34 * Lustre is a trademark of Sun Microsystems, Inc.
38 #include <linux/sched.h>
40 #include <linux/smp_lock.h>
41 #include <linux/highmem.h>
42 #include <linux/pagemap.h>
44 #define DEBUG_SUBSYSTEM S_LLITE
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"
54 unsigned int se_index;
56 struct ptlrpc_request *se_req;
57 struct md_enqueue_info *se_minfo;
61 SA_ENTRY_UNSTATED = 0,
65 static unsigned int sai_generation = 0;
66 static cfs_spinlock_t sai_generation_lock = CFS_SPIN_LOCK_UNLOCKED;
69 * Check whether first entry was stated already or not.
70 * No need to hold lli_sa_lock, for:
71 * (1) it is me that remove entry from the list
72 * (2) the statahead thread only add new entry to the list
74 static int ll_sai_entry_stated(struct ll_statahead_info *sai)
76 struct ll_sai_entry *entry;
79 if (!cfs_list_empty(&sai->sai_entries_stated)) {
80 entry = cfs_list_entry(sai->sai_entries_stated.next,
81 struct ll_sai_entry, se_list);
82 if (entry->se_index == sai->sai_index_next)
88 static inline int sa_received_empty(struct ll_statahead_info *sai)
90 return cfs_list_empty(&sai->sai_entries_received);
93 static inline int sa_not_full(struct ll_statahead_info *sai)
95 return !!(sai->sai_index < sai->sai_index_next + sai->sai_max);
98 static inline int sa_is_running(struct ll_statahead_info *sai)
100 return !!(sai->sai_thread.t_flags & SVC_RUNNING);
103 static inline int sa_is_stopping(struct ll_statahead_info *sai)
105 return !!(sai->sai_thread.t_flags & SVC_STOPPING);
108 static inline int sa_is_stopped(struct ll_statahead_info *sai)
110 return !!(sai->sai_thread.t_flags & SVC_STOPPED);
114 * (1) hit ratio less than 80%
116 * (2) consecutive miss more than 8
118 static inline int sa_low_hit(struct ll_statahead_info *sai)
120 return ((sai->sai_hit > 7 && sai->sai_hit < 4 * sai->sai_miss) ||
121 (sai->sai_consecutive_miss > 8));
125 * process the deleted entry's member and free the entry.
127 * (2) free md_enqueue_info
128 * (3) drop dentry's ref count
129 * (4) release request's ref count
131 static void ll_sai_entry_cleanup(struct ll_sai_entry *entry, int free)
133 struct md_enqueue_info *minfo = entry->se_minfo;
134 struct ptlrpc_request *req = entry->se_req;
138 entry->se_minfo = NULL;
139 ll_intent_release(&minfo->mi_it);
140 dput(minfo->mi_dentry);
145 entry->se_req = NULL;
146 ptlrpc_req_finished(req);
149 LASSERT(cfs_list_empty(&entry->se_list));
156 static struct ll_statahead_info *ll_sai_alloc(void)
158 struct ll_statahead_info *sai;
164 cfs_spin_lock(&sai_generation_lock);
165 sai->sai_generation = ++sai_generation;
166 if (unlikely(sai_generation == 0))
167 sai->sai_generation = ++sai_generation;
168 cfs_spin_unlock(&sai_generation_lock);
169 cfs_atomic_set(&sai->sai_refcount, 1);
170 sai->sai_max = LL_SA_RPC_MIN;
171 cfs_waitq_init(&sai->sai_waitq);
172 cfs_waitq_init(&sai->sai_thread.t_ctl_waitq);
173 CFS_INIT_LIST_HEAD(&sai->sai_entries_sent);
174 CFS_INIT_LIST_HEAD(&sai->sai_entries_received);
175 CFS_INIT_LIST_HEAD(&sai->sai_entries_stated);
180 struct ll_statahead_info *ll_sai_get(struct ll_statahead_info *sai)
183 cfs_atomic_inc(&sai->sai_refcount);
187 static void ll_sai_put(struct ll_statahead_info *sai)
189 struct inode *inode = sai->sai_inode;
190 struct ll_inode_info *lli;
193 LASSERT(inode != NULL);
194 lli = ll_i2info(inode);
195 LASSERT(lli->lli_sai == sai);
197 if (cfs_atomic_dec_and_lock(&sai->sai_refcount, &lli->lli_sa_lock)) {
198 struct ll_sai_entry *entry, *next;
200 if (unlikely(cfs_atomic_read(&sai->sai_refcount) > 0)) {
201 /* It is race case, the interpret callback just hold
202 * a reference count */
203 cfs_spin_unlock(&lli->lli_sa_lock);
207 LASSERT(lli->lli_opendir_key == NULL);
209 lli->lli_opendir_pid = 0;
210 cfs_spin_unlock(&lli->lli_sa_lock);
212 LASSERT(sa_is_stopped(sai));
214 if (sai->sai_sent > sai->sai_replied)
215 CDEBUG(D_READA,"statahead for dir "DFID" does not "
216 "finish: [sent:%u] [replied:%u]\n",
218 sai->sai_sent, sai->sai_replied);
220 cfs_list_for_each_entry_safe(entry, next,
221 &sai->sai_entries_sent, se_list) {
222 cfs_list_del_init(&entry->se_list);
223 ll_sai_entry_cleanup(entry, 1);
225 cfs_list_for_each_entry_safe(entry, next,
226 &sai->sai_entries_received,
228 cfs_list_del_init(&entry->se_list);
229 ll_sai_entry_cleanup(entry, 1);
231 cfs_list_for_each_entry_safe(entry, next,
232 &sai->sai_entries_stated,
234 cfs_list_del_init(&entry->se_list);
235 ll_sai_entry_cleanup(entry, 1);
244 * insert it into sai_entries_sent tail when init.
246 static struct ll_sai_entry *
247 ll_sai_entry_init(struct ll_statahead_info *sai, unsigned int index)
249 struct ll_inode_info *lli = ll_i2info(sai->sai_inode);
250 struct ll_sai_entry *entry;
253 OBD_ALLOC_PTR(entry);
255 RETURN(ERR_PTR(-ENOMEM));
257 CDEBUG(D_READA, "alloc sai entry %p index %u\n",
259 entry->se_index = index;
260 entry->se_stat = SA_ENTRY_UNSTATED;
262 cfs_spin_lock(&lli->lli_sa_lock);
263 cfs_list_add_tail(&entry->se_list, &sai->sai_entries_sent);
264 cfs_spin_unlock(&lli->lli_sa_lock);
270 * delete it from sai_entries_stated head when fini, it need not
271 * to process entry's member.
273 static int ll_sai_entry_fini(struct ll_statahead_info *sai)
275 struct ll_inode_info *lli = ll_i2info(sai->sai_inode);
276 struct ll_sai_entry *entry;
280 cfs_spin_lock(&lli->lli_sa_lock);
281 sai->sai_index_next++;
282 if (likely(!cfs_list_empty(&sai->sai_entries_stated))) {
283 entry = cfs_list_entry(sai->sai_entries_stated.next,
284 struct ll_sai_entry, se_list);
285 if (entry->se_index < sai->sai_index_next) {
286 cfs_list_del_init(&entry->se_list);
291 LASSERT(sa_is_stopped(sai));
293 cfs_spin_unlock(&lli->lli_sa_lock);
299 * inside lli_sa_lock.
300 * \retval NULL : can not find the entry in sai_entries_sent with the index
301 * \retval entry: find the entry in sai_entries_sent with the index
303 static struct ll_sai_entry *
304 ll_sai_entry_set(struct ll_statahead_info *sai, unsigned int index, int stat,
305 struct ptlrpc_request *req, struct md_enqueue_info *minfo)
307 struct ll_sai_entry *entry;
310 if (!cfs_list_empty(&sai->sai_entries_sent)) {
311 cfs_list_for_each_entry(entry, &sai->sai_entries_sent,
313 if (entry->se_index == index) {
314 entry->se_stat = stat;
315 entry->se_req = ptlrpc_request_addref(req);
316 entry->se_minfo = minfo;
318 } else if (entry->se_index > index) {
327 * inside lli_sa_lock.
328 * Move entry to sai_entries_received and
329 * insert it into sai_entries_received tail.
332 ll_sai_entry_to_received(struct ll_statahead_info *sai, struct ll_sai_entry *entry)
334 if (!cfs_list_empty(&entry->se_list))
335 cfs_list_del_init(&entry->se_list);
336 cfs_list_add_tail(&entry->se_list, &sai->sai_entries_received);
340 * Move entry to sai_entries_stated and
341 * sort with the index.
344 ll_sai_entry_to_stated(struct ll_statahead_info *sai, struct ll_sai_entry *entry)
346 struct ll_inode_info *lli = ll_i2info(sai->sai_inode);
347 struct ll_sai_entry *se;
350 ll_sai_entry_cleanup(entry, 0);
352 cfs_spin_lock(&lli->lli_sa_lock);
353 if (!cfs_list_empty(&entry->se_list))
354 cfs_list_del_init(&entry->se_list);
357 if (unlikely(entry->se_index < sai->sai_index_next)) {
358 cfs_spin_unlock(&lli->lli_sa_lock);
363 cfs_list_for_each_entry_reverse(se, &sai->sai_entries_stated, se_list) {
364 if (se->se_index < entry->se_index) {
365 cfs_list_add(&entry->se_list, &se->se_list);
366 cfs_spin_unlock(&lli->lli_sa_lock);
372 * I am the first entry.
374 cfs_list_add(&entry->se_list, &sai->sai_entries_stated);
375 cfs_spin_unlock(&lli->lli_sa_lock);
380 * finish lookup/revalidate.
382 static int do_statahead_interpret(struct ll_statahead_info *sai)
384 struct ll_inode_info *lli = ll_i2info(sai->sai_inode);
385 struct ll_sai_entry *entry;
386 struct ptlrpc_request *req;
387 struct md_enqueue_info *minfo;
388 struct lookup_intent *it;
389 struct dentry *dentry;
391 struct mdt_body *body;
394 cfs_spin_lock(&lli->lli_sa_lock);
395 LASSERT(!sa_received_empty(sai));
396 entry = cfs_list_entry(sai->sai_entries_received.next,
397 struct ll_sai_entry, se_list);
398 cfs_list_del_init(&entry->se_list);
399 cfs_spin_unlock(&lli->lli_sa_lock);
401 if (unlikely(entry->se_index < sai->sai_index_next)) {
402 CWARN("Found stale entry: [index %u] [next %u]\n",
403 entry->se_index, sai->sai_index_next);
404 ll_sai_entry_cleanup(entry, 1);
408 if (entry->se_stat != SA_ENTRY_STATED)
409 GOTO(out, rc = entry->se_stat);
412 minfo = entry->se_minfo;
414 dentry = minfo->mi_dentry;
416 body = req_capsule_server_get(&req->rq_pill, &RMF_MDT_BODY);
418 GOTO(out, rc = -EFAULT);
420 if (dentry->d_inode == NULL) {
424 struct dentry *save = dentry;
425 struct it_cb_data icbd = {
426 .icbd_parent = minfo->mi_dir,
427 .icbd_childp = &dentry
430 LASSERT(fid_is_zero(&minfo->mi_data.op_fid2));
432 /* XXX: No fid in reply, this is probaly cross-ref case.
433 * SA can't handle it yet. */
434 if (body->valid & OBD_MD_MDS)
435 GOTO(out, rc = -EAGAIN);
437 /* Here dentry->d_inode might be NULL, because the entry may
438 * have been removed before we start doing stat ahead. */
439 rc = ll_lookup_it_finish(req, it, &icbd);
441 ll_lookup_finish_locks(it, dentry);
443 if (dentry != save) {
444 minfo->mi_dentry = dentry;
451 if (!lu_fid_eq(&minfo->mi_data.op_fid2, &body->fid1)) {
452 ll_unhash_aliases(dentry->d_inode);
453 GOTO(out, rc = -EAGAIN);
456 rc = ll_revalidate_it_finish(req, it, dentry);
458 ll_unhash_aliases(dentry->d_inode);
462 cfs_spin_lock(&ll_lookup_lock);
463 spin_lock(&dcache_lock);
466 dentry->d_flags &= ~DCACHE_LUSTRE_INVALID;
467 unlock_dentry(dentry);
468 d_rehash_cond(dentry, 0);
469 spin_unlock(&dcache_lock);
470 cfs_spin_unlock(&ll_lookup_lock);
472 ll_lookup_finish_locks(it, dentry);
477 /* The "ll_sai_entry_to_stated()" will drop related ldlm ibits lock
478 * reference count with ll_intent_drop_lock() called in spite of the
479 * above operations failed or not. Do not worry about calling
480 * "ll_intent_drop_lock()" more than once. */
481 if (likely(ll_sai_entry_to_stated(sai, entry)))
482 cfs_waitq_signal(&sai->sai_waitq);
486 static int ll_statahead_interpret(struct ptlrpc_request *req,
487 struct md_enqueue_info *minfo,
490 struct lookup_intent *it = &minfo->mi_it;
491 struct dentry *dentry = minfo->mi_dentry;
492 struct inode *dir = minfo->mi_dir;
493 struct ll_inode_info *lli = ll_i2info(dir);
494 struct ll_statahead_info *sai;
495 struct ll_sai_entry *entry;
498 CDEBUG(D_READA, "interpret statahead %.*s rc %d\n",
499 dentry->d_name.len, dentry->d_name.name, rc);
501 cfs_spin_lock(&lli->lli_sa_lock);
503 if (unlikely(lli->lli_sai == NULL ||
504 lli->lli_sai->sai_generation != minfo->mi_generation)) {
505 cfs_spin_unlock(&lli->lli_sa_lock);
506 ll_intent_release(it);
512 sai = ll_sai_get(lli->lli_sai);
513 entry = ll_sai_entry_set(sai,
514 (unsigned int)(long)minfo->mi_cbdata,
515 rc < 0 ? rc : SA_ENTRY_STATED, req,
517 LASSERT(entry != NULL);
518 if (likely(sa_is_running(sai))) {
519 ll_sai_entry_to_received(sai, entry);
521 cfs_spin_unlock(&lli->lli_sa_lock);
522 cfs_waitq_signal(&sai->sai_thread.t_ctl_waitq);
524 if (!cfs_list_empty(&entry->se_list))
525 cfs_list_del_init(&entry->se_list);
527 cfs_spin_unlock(&lli->lli_sa_lock);
528 ll_sai_entry_cleanup(entry, 1);
535 static void sa_args_fini(struct md_enqueue_info *minfo,
536 struct ldlm_enqueue_info *einfo)
538 LASSERT(minfo && einfo);
540 capa_put(minfo->mi_data.op_capa1);
541 capa_put(minfo->mi_data.op_capa2);
547 * There is race condition between "capa_put" and "ll_statahead_interpret" for
548 * accessing "op_data.op_capa[1,2]" as following:
549 * "capa_put" releases "op_data.op_capa[1,2]"'s reference count after calling
550 * "md_intent_getattr_async". But "ll_statahead_interpret" maybe run first, and
551 * fill "op_data.op_capa[1,2]" as POISON, then cause "capa_put" access invalid
552 * "ocapa". So here reserve "op_data.op_capa[1,2]" in "pcapa" before calling
553 * "md_intent_getattr_async".
555 static int sa_args_init(struct inode *dir, struct dentry *dentry,
556 struct md_enqueue_info **pmi,
557 struct ldlm_enqueue_info **pei,
558 struct obd_capa **pcapa)
560 struct ll_inode_info *lli = ll_i2info(dir);
561 struct md_enqueue_info *minfo;
562 struct ldlm_enqueue_info *einfo;
563 struct md_op_data *op_data;
565 OBD_ALLOC_PTR(einfo);
569 OBD_ALLOC_PTR(minfo);
575 op_data = ll_prep_md_op_data(&minfo->mi_data, dir, dentry->d_inode,
576 dentry->d_name.name, dentry->d_name.len,
577 0, LUSTRE_OPC_ANY, NULL);
578 if (IS_ERR(op_data)) {
581 return PTR_ERR(op_data);
584 minfo->mi_it.it_op = IT_GETATTR;
585 minfo->mi_dentry = dentry;
586 minfo->mi_dir = igrab(dir);
587 minfo->mi_cb = ll_statahead_interpret;
588 minfo->mi_generation = lli->lli_sai->sai_generation;
589 minfo->mi_cbdata = (void *)(long)lli->lli_sai->sai_index;
591 einfo->ei_type = LDLM_IBITS;
592 einfo->ei_mode = it_to_lock_mode(&minfo->mi_it);
593 einfo->ei_cb_bl = ll_md_blocking_ast;
594 einfo->ei_cb_cp = ldlm_completion_ast;
595 einfo->ei_cb_gl = NULL;
596 einfo->ei_cbdata = NULL;
600 pcapa[0] = op_data->op_capa1;
601 pcapa[1] = op_data->op_capa2;
607 * similar to ll_lookup_it().
609 static int do_sa_lookup(struct inode *dir, struct dentry *dentry)
611 struct md_enqueue_info *minfo;
612 struct ldlm_enqueue_info *einfo;
613 struct obd_capa *capas[2];
617 rc = sa_args_init(dir, dentry, &minfo, &einfo, capas);
621 rc = md_intent_getattr_async(ll_i2mdexp(dir), minfo, einfo);
626 sa_args_fini(minfo, einfo);
633 * similar to ll_revalidate_it().
634 * \retval 1 -- dentry valid
635 * \retval 0 -- will send stat-ahead request
636 * \retval others -- prepare stat-ahead request failed
638 static int do_sa_revalidate(struct inode *dir, struct dentry *dentry)
640 struct inode *inode = dentry->d_inode;
641 struct lookup_intent it = { .it_op = IT_GETATTR };
642 struct md_enqueue_info *minfo;
643 struct ldlm_enqueue_info *einfo;
644 struct obd_capa *capas[2];
648 if (unlikely(inode == NULL))
651 if (d_mountpoint(dentry))
654 if (unlikely(dentry == dentry->d_sb->s_root))
657 rc = md_revalidate_lock(ll_i2mdexp(dir), &it, ll_inode2fid(inode));
659 ll_intent_release(&it);
663 rc = sa_args_init(dir, dentry, &minfo, &einfo, capas);
667 rc = md_intent_getattr_async(ll_i2mdexp(dir), minfo, einfo);
672 sa_args_fini(minfo, einfo);
678 static inline void ll_name2qstr(struct qstr *q, const char *name, int namelen)
682 q->hash = full_name_hash(name, namelen);
685 static int ll_statahead_one(struct dentry *parent, const char* entry_name,
688 struct inode *dir = parent->d_inode;
689 struct ll_inode_info *lli = ll_i2info(dir);
690 struct ll_statahead_info *sai = lli->lli_sai;
692 struct dentry *dentry = NULL;
693 struct ll_sai_entry *se;
697 if (parent->d_flags & DCACHE_LUSTRE_INVALID) {
698 CDEBUG(D_READA, "parent dentry@%p %.*s is "
699 "invalid, skip statahead\n",
700 parent, parent->d_name.len, parent->d_name.name);
704 se = ll_sai_entry_init(sai, sai->sai_index);
708 ll_name2qstr(&name, entry_name, entry_name_len);
709 dentry = d_lookup(parent, &name);
711 dentry = d_alloc(parent, &name);
713 rc = do_sa_lookup(dir, dentry);
715 GOTO(out, rc = -ENOMEM);
717 rc = do_sa_revalidate(dir, dentry);
726 se->se_stat = rc < 0 ? rc : SA_ENTRY_STATED;
727 CDEBUG(D_READA, "set sai entry %p index %u stat %d rc %d\n",
728 se, se->se_index, se->se_stat, rc);
729 if (ll_sai_entry_to_stated(sai, se))
730 cfs_waitq_signal(&sai->sai_waitq);
739 static int ll_statahead_thread(void *arg)
741 struct dentry *parent = (struct dentry *)arg;
742 struct inode *dir = parent->d_inode;
743 struct ll_inode_info *lli = ll_i2info(dir);
744 struct ll_sb_info *sbi = ll_i2sbi(dir);
745 struct ll_statahead_info *sai = ll_sai_get(lli->lli_sai);
746 struct ptlrpc_thread *thread = &sai->sai_thread;
751 struct ll_dir_chain chain;
756 snprintf(pname, 15, "ll_sa_%u", lli->lli_opendir_pid);
757 cfs_daemonize(pname);
760 atomic_inc(&sbi->ll_sa_total);
761 cfs_spin_lock(&lli->lli_sa_lock);
762 thread->t_flags = SVC_RUNNING;
763 cfs_spin_unlock(&lli->lli_sa_lock);
764 cfs_waitq_signal(&thread->t_ctl_waitq);
765 CDEBUG(D_READA, "start doing statahead for %s\n", parent->d_name.name);
767 sai->sai_pid = cfs_curproc_pid();
769 ll_dir_chain_init(&chain);
770 page = ll_get_dir_page(NULL, dir, pos, 0, &chain);
773 struct l_wait_info lwi = { 0 };
774 struct lu_dirpage *dp;
775 struct lu_dirent *ent;
779 CDEBUG(D_READA, "error reading dir "DFID" at "LPU64
780 "/%u: [rc %d] [parent %u]\n",
781 PFID(ll_inode2fid(dir)), pos, sai->sai_index,
782 rc, lli->lli_opendir_pid);
786 dp = page_address(page);
787 for (ent = lu_dirent_start(dp); ent != NULL;
788 ent = lu_dirent_next(ent)) {
793 hash = le64_to_cpu(ent->lde_hash);
794 if (unlikely(hash < pos))
796 * Skip until we find target hash value.
800 namelen = le16_to_cpu(ent->lde_namelen);
801 if (unlikely(namelen == 0))
807 name = ent->lde_name;
808 if (name[0] == '.') {
814 } else if (name[1] == '.' && namelen == 2) {
819 } else if (!sai->sai_ls_all) {
823 sai->sai_skip_hidden++;
829 * don't stat-ahead first entry.
831 if (unlikely(!first)) {
837 l_wait_event(thread->t_ctl_waitq,
838 !sa_is_running(sai) || sa_not_full(sai) ||
839 !sa_received_empty(sai),
842 while (!sa_received_empty(sai) && sa_is_running(sai))
843 do_statahead_interpret(sai);
845 if (unlikely(!sa_is_running(sai))) {
850 if (!sa_not_full(sai))
852 * do not skip the current de.
856 rc = ll_statahead_one(parent, name, namelen);
862 pos = le64_to_cpu(dp->ldp_hash_end);
864 if (pos == DIR_END_OFF) {
866 * End of directory reached.
869 l_wait_event(thread->t_ctl_waitq,
870 !sa_is_running(sai) ||
871 !sa_received_empty(sai) ||
872 sai->sai_sent == sai->sai_replied,
874 if (!sa_received_empty(sai) &&
876 do_statahead_interpret(sai);
882 * chain is exhausted.
883 * Normal case: continue to the next page.
885 lli->lli_sa_pos = pos;
886 page = ll_get_dir_page(NULL, dir, pos, 1, &chain);
889 * go into overflow page.
896 ll_dir_chain_fini(&chain);
897 cfs_spin_lock(&lli->lli_sa_lock);
898 thread->t_flags = SVC_STOPPED;
899 cfs_spin_unlock(&lli->lli_sa_lock);
900 cfs_waitq_signal(&sai->sai_waitq);
901 cfs_waitq_signal(&thread->t_ctl_waitq);
904 CDEBUG(D_READA, "statahead thread stopped, pid %d\n",
910 * called in ll_file_release().
912 void ll_stop_statahead(struct inode *dir, void *key)
914 struct ll_inode_info *lli = ll_i2info(dir);
916 if (unlikely(key == NULL))
919 cfs_spin_lock(&lli->lli_sa_lock);
920 if (lli->lli_opendir_key != key || lli->lli_opendir_pid == 0) {
921 cfs_spin_unlock(&lli->lli_sa_lock);
925 lli->lli_opendir_key = NULL;
928 struct l_wait_info lwi = { 0 };
929 struct ptlrpc_thread *thread = &lli->lli_sai->sai_thread;
931 if (!sa_is_stopped(lli->lli_sai)) {
932 thread->t_flags = SVC_STOPPING;
933 cfs_spin_unlock(&lli->lli_sa_lock);
934 cfs_waitq_signal(&thread->t_ctl_waitq);
936 CDEBUG(D_READA, "stopping statahead thread, pid %d\n",
938 l_wait_event(thread->t_ctl_waitq,
939 sa_is_stopped(lli->lli_sai),
942 cfs_spin_unlock(&lli->lli_sa_lock);
946 * Put the ref which was held when first statahead_enter.
947 * It maybe not the last ref for some statahead requests
950 ll_sai_put(lli->lli_sai);
952 lli->lli_opendir_pid = 0;
953 cfs_spin_unlock(&lli->lli_sa_lock);
959 * not first dirent, or is "."
961 LS_NONE_FIRST_DE = 0,
963 * the first non-hidden dirent
967 * the first hidden dirent, that is "."
972 static int is_first_dirent(struct inode *dir, struct dentry *dentry)
974 struct ll_inode_info *lli = ll_i2info(dir);
975 struct ll_dir_chain chain;
976 struct qstr *target = &dentry->d_name;
980 int rc = LS_NONE_FIRST_DE;
984 ll_dir_chain_init(&chain);
985 page = ll_get_dir_page(NULL, dir, pos, 0, &chain);
988 struct lu_dirpage *dp;
989 struct lu_dirent *ent;
992 struct ll_inode_info *lli = ll_i2info(dir);
995 CERROR("error reading dir "DFID" at "LPU64": "
996 "[rc %d] [parent %u]\n",
997 PFID(ll_inode2fid(dir)), pos,
998 rc, lli->lli_opendir_pid);
1002 dp = page_address(page);
1003 for (ent = lu_dirent_start(dp); ent != NULL;
1004 ent = lu_dirent_next(ent)) {
1008 namelen = le16_to_cpu(ent->lde_namelen);
1009 if (unlikely(namelen == 0))
1011 * skip dummy record.
1015 name = ent->lde_name;
1016 if (name[0] == '.') {
1022 else if (name[1] == '.' && namelen == 2)
1033 if (dot_de && target->name[0] != '.') {
1034 CDEBUG(D_READA, "%.*s skip hidden file %.*s\n",
1035 target->len, target->name,
1040 if (target->len != namelen ||
1041 memcmp(target->name, name, namelen) != 0)
1042 rc = LS_NONE_FIRST_DE;
1046 rc = LS_FIRST_DOT_DE;
1051 pos = le64_to_cpu(dp->ldp_hash_end);
1053 if (pos == DIR_END_OFF) {
1055 * End of directory reached.
1060 * chain is exhausted
1061 * Normal case: continue to the next page.
1063 lli->lli_sa_pos = pos;
1064 page = ll_get_dir_page(NULL, dir, pos, 1, &chain);
1067 * go into overflow page.
1074 ll_dir_chain_fini(&chain);
1079 * Start statahead thread if this is the first dir entry.
1080 * Otherwise if a thread is started already, wait it until it is ahead of me.
1081 * \retval 0 -- stat ahead thread process such dentry, for lookup, it miss
1082 * \retval 1 -- stat ahead thread process such dentry, for lookup, it hit
1083 * \retval -EEXIST -- stat ahead thread started, and this is the first dentry
1084 * \retval -EBADFD -- statahead thread exit and not dentry available
1085 * \retval -EAGAIN -- try to stat by caller
1086 * \retval others -- error
1088 int do_statahead_enter(struct inode *dir, struct dentry **dentryp, int lookup)
1090 struct ll_inode_info *lli;
1091 struct ll_statahead_info *sai;
1092 struct dentry *parent;
1093 struct l_wait_info lwi = { 0 };
1097 LASSERT(dir != NULL);
1098 lli = ll_i2info(dir);
1099 LASSERT(lli->lli_opendir_pid == cfs_curproc_pid());
1103 if (unlikely(sa_is_stopped(sai) &&
1104 cfs_list_empty(&sai->sai_entries_stated)))
1107 if ((*dentryp)->d_name.name[0] == '.') {
1108 if (likely(sai->sai_ls_all ||
1109 sai->sai_miss_hidden >= sai->sai_skip_hidden)) {
1111 * Hidden dentry is the first one, or statahead
1112 * thread does not skip so many hidden dentries
1113 * before "sai_ls_all" enabled as below.
1116 if (!sai->sai_ls_all)
1118 * It maybe because hidden dentry is not
1119 * the first one, "sai_ls_all" was not
1120 * set, then "ls -al" missed. Enable
1121 * "sai_ls_all" for such case.
1123 sai->sai_ls_all = 1;
1126 * Such "getattr" has been skipped before
1127 * "sai_ls_all" enabled as above.
1129 sai->sai_miss_hidden++;
1134 if (!ll_sai_entry_stated(sai)) {
1136 * thread started already, avoid double-stat.
1138 lwi = LWI_INTR(LWI_ON_SIGNAL_NOOP, NULL);
1139 rc = l_wait_event(sai->sai_waitq,
1140 ll_sai_entry_stated(sai) ||
1143 if (unlikely(rc == -EINTR))
1148 struct dentry *result;
1150 result = d_lookup((*dentryp)->d_parent,
1151 &(*dentryp)->d_name);
1153 LASSERT(result != *dentryp);
1154 /* BUG 16303: do not drop reference count for
1155 * "*dentryp", VFS will do that by itself. */
1161 * do nothing for revalidate.
1166 /* I am the "lli_opendir_pid" owner, only me can set "lli_sai". */
1167 rc = is_first_dirent(dir, *dentryp);
1168 if (rc == LS_NONE_FIRST_DE)
1169 /* It is not "ls -{a}l" operation, no need statahead for it. */
1170 GOTO(out, rc = -EAGAIN);
1172 sai = ll_sai_alloc();
1174 GOTO(out, rc = -ENOMEM);
1176 sai->sai_ls_all = (rc == LS_FIRST_DOT_DE);
1177 sai->sai_inode = igrab(dir);
1178 if (unlikely(sai->sai_inode == NULL)) {
1179 CWARN("Do not start stat ahead on dying inode "DFID"\n",
1180 PFID(&lli->lli_fid));
1182 GOTO(out, rc = -ESTALE);
1185 /* get parent reference count here, and put it in ll_statahead_thread */
1186 parent = dget((*dentryp)->d_parent);
1187 if (unlikely(sai->sai_inode != parent->d_inode)) {
1188 struct ll_inode_info *nlli = ll_i2info(parent->d_inode);
1190 CWARN("Race condition, someone changed %.*s just now: "
1191 "old parent "DFID", new parent "DFID"\n",
1192 (*dentryp)->d_name.len, (*dentryp)->d_name.name,
1193 PFID(&lli->lli_fid), PFID(&nlli->lli_fid));
1195 iput(sai->sai_inode);
1201 rc = cfs_kernel_thread(ll_statahead_thread, parent, 0);
1203 CERROR("can't start ll_sa thread, rc: %d\n", rc);
1205 lli->lli_opendir_key = NULL;
1206 sai->sai_thread.t_flags = SVC_STOPPED;
1208 LASSERT(lli->lli_sai == NULL);
1212 l_wait_event(sai->sai_thread.t_ctl_waitq,
1213 sa_is_running(sai) || sa_is_stopped(sai),
1217 * We don't stat-ahead for the first dirent since we are already in
1218 * lookup, and -EEXIST also indicates that this is the first dirent.
1223 cfs_spin_lock(&lli->lli_sa_lock);
1224 lli->lli_opendir_key = NULL;
1225 lli->lli_opendir_pid = 0;
1226 cfs_spin_unlock(&lli->lli_sa_lock);
1231 * update hit/miss count.
1233 void ll_statahead_exit(struct inode *dir, struct dentry *dentry, int result)
1235 struct ll_inode_info *lli;
1236 struct ll_statahead_info *sai;
1237 struct ll_sb_info *sbi;
1238 struct ll_dentry_data *ldd = ll_d2d(dentry);
1242 LASSERT(dir != NULL);
1243 lli = ll_i2info(dir);
1244 LASSERT(lli->lli_opendir_pid == cfs_curproc_pid());
1246 LASSERT(sai != NULL);
1247 sbi = ll_i2sbi(dir);
1249 rc = ll_sai_entry_fini(sai);
1250 /* rc == -ENOENT means such dentry was removed just between statahead
1251 * readdir and pre-fetched, count it as hit.
1253 * result == -ENOENT has two meanings:
1254 * 1. such dentry was removed just between statahead pre-fetched and
1255 * main process stat such dentry.
1256 * 2. main process stat non-exist dentry.
1257 * We can not distinguish such two cases, just count them as miss. */
1258 if (result >= 1 || unlikely(rc == -ENOENT)) {
1260 sai->sai_consecutive_miss = 0;
1261 sai->sai_max = min(2 * sai->sai_max, sbi->ll_sa_max);
1264 sai->sai_consecutive_miss++;
1265 if (sa_low_hit(sai) && sa_is_running(sai)) {
1266 atomic_inc(&sbi->ll_sa_wrong);
1267 CDEBUG(D_READA, "Statahead for dir "DFID" hit ratio "
1268 "too low: hit/miss %u/%u, sent/replied %u/%u, "
1269 "stopping statahead thread: pid %d\n",
1270 PFID(&lli->lli_fid), sai->sai_hit,
1271 sai->sai_miss, sai->sai_sent,
1272 sai->sai_replied, cfs_curproc_pid());
1273 cfs_spin_lock(&lli->lli_sa_lock);
1274 if (!sa_is_stopped(sai))
1275 sai->sai_thread.t_flags = SVC_STOPPING;
1276 cfs_spin_unlock(&lli->lli_sa_lock);
1280 if (!sa_is_stopped(sai))
1281 cfs_waitq_signal(&sai->sai_thread.t_ctl_waitq);
1282 if (likely(ldd != NULL))
1283 ldd->lld_sa_generation = sai->sai_generation;