4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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.
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).
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
23 * Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
24 * Use is subject to license terms.
26 * Copyright (c) 2011, 2017, Intel Corporation.
29 * This file is part of Lustre, http://www.lustre.org/
33 #include <linux/sched.h>
34 #include <linux/kthread.h>
36 #include <linux/highmem.h>
37 #include <linux/pagemap.h>
38 #include <linux/delay.h>
40 #define DEBUG_SUBSYSTEM S_LLITE
42 #include <obd_support.h>
43 #include <lustre_dlm.h>
44 #include "llite_internal.h"
46 #define SA_OMITTED_ENTRY_MAX 8ULL
49 /** negative values are for error cases */
50 SA_ENTRY_INIT = 0, /** init entry */
51 SA_ENTRY_SUCC = 1, /** stat succeed */
52 SA_ENTRY_INVA = 2, /** invalid entry */
56 * sa_entry is not refcounted: statahead thread allocates it and do async stat,
57 * and in async stat callback ll_statahead_interpret() will prepare the inode
58 * and set lock data in the ptlrpcd context. Then the scanner process will be
59 * woken up if this entry is the waiting one, can access and free it.
62 /* link into sai_entries */
63 struct list_head se_list;
64 /* link into sai hash table locally */
65 struct list_head se_hash;
66 /* entry index in the sai */
68 /* low layer ldlm lock handle */
72 /* entry size, contains name */
74 /* pointer to the target inode */
75 struct inode *se_inode;
82 static unsigned int sai_generation;
83 static DEFINE_SPINLOCK(sai_generation_lock);
85 static inline int sa_unhashed(struct sa_entry *entry)
87 return list_empty(&entry->se_hash);
90 /* sa_entry is ready to use */
91 static inline int sa_ready(struct sa_entry *entry)
93 /* Make sure sa_entry is updated and ready to use */
95 return (entry->se_state != SA_ENTRY_INIT);
98 /* hash value to put in sai_cache */
99 static inline int sa_hash(int val)
101 return val & LL_SA_CACHE_MASK;
104 /* hash entry into sai_cache */
106 sa_rehash(struct ll_statahead_info *sai, struct sa_entry *entry)
108 int i = sa_hash(entry->se_qstr.hash);
110 spin_lock(&sai->sai_cache_lock[i]);
111 list_add_tail(&entry->se_hash, &sai->sai_cache[i]);
112 spin_unlock(&sai->sai_cache_lock[i]);
115 /* unhash entry from sai_cache */
117 sa_unhash(struct ll_statahead_info *sai, struct sa_entry *entry)
119 int i = sa_hash(entry->se_qstr.hash);
121 spin_lock(&sai->sai_cache_lock[i]);
122 list_del_init(&entry->se_hash);
123 spin_unlock(&sai->sai_cache_lock[i]);
126 static inline int agl_should_run(struct ll_statahead_info *sai,
129 return inode && S_ISREG(inode->i_mode) && sai->sai_agl_task;
132 static inline struct ll_inode_info *
133 agl_first_entry(struct ll_statahead_info *sai)
135 return list_first_entry(&sai->sai_agls, struct ll_inode_info,
139 /* statahead window is full */
140 static inline int sa_sent_full(struct ll_statahead_info *sai)
142 return atomic_read(&sai->sai_cache_count) >= sai->sai_max;
145 static inline int agl_list_empty(struct ll_statahead_info *sai)
147 return list_empty(&sai->sai_agls);
151 * (1) hit ratio less than 80%
153 * (2) consecutive miss more than 8
154 * then means low hit.
156 static inline int sa_low_hit(struct ll_statahead_info *sai)
158 return ((sai->sai_hit > 7 && sai->sai_hit < 4 * sai->sai_miss) ||
159 (sai->sai_consecutive_miss > 8));
163 * if the given index is behind of statahead window more than
164 * SA_OMITTED_ENTRY_MAX, then it is old.
166 static inline int is_omitted_entry(struct ll_statahead_info *sai, __u64 index)
168 return ((__u64)sai->sai_max + index + SA_OMITTED_ENTRY_MAX <
172 /* allocate sa_entry and hash it to allow scanner process to find it */
173 static struct sa_entry *
174 sa_alloc(struct dentry *parent, struct ll_statahead_info *sai, __u64 index,
175 const char *name, int len, const struct lu_fid *fid)
177 struct ll_inode_info *lli;
178 struct sa_entry *entry;
184 entry_size = sizeof(struct sa_entry) + (len & ~3) + 4;
185 OBD_ALLOC(entry, entry_size);
186 if (unlikely(!entry))
187 RETURN(ERR_PTR(-ENOMEM));
189 CDEBUG(D_READA, "alloc sa entry %.*s(%p) index %llu\n",
190 len, name, entry, index);
192 entry->se_index = index;
194 entry->se_state = SA_ENTRY_INIT;
195 entry->se_size = entry_size;
196 dname = (char *)entry + sizeof(struct sa_entry);
197 memcpy(dname, name, len);
199 entry->se_qstr.hash = ll_full_name_hash(parent, name, len);
200 entry->se_qstr.len = len;
201 entry->se_qstr.name = dname;
202 entry->se_fid = *fid;
204 lli = ll_i2info(sai->sai_dentry->d_inode);
206 spin_lock(&lli->lli_sa_lock);
207 INIT_LIST_HEAD(&entry->se_list);
208 sa_rehash(sai, entry);
209 spin_unlock(&lli->lli_sa_lock);
211 atomic_inc(&sai->sai_cache_count);
216 /* free sa_entry, which should have been unhashed and not in any list */
217 static void sa_free(struct ll_statahead_info *sai, struct sa_entry *entry)
219 CDEBUG(D_READA, "free sa entry %.*s(%p) index %llu\n",
220 entry->se_qstr.len, entry->se_qstr.name, entry,
223 LASSERT(list_empty(&entry->se_list));
224 LASSERT(sa_unhashed(entry));
226 OBD_FREE(entry, entry->se_size);
227 atomic_dec(&sai->sai_cache_count);
231 * find sa_entry by name, used by directory scanner, lock is not needed because
232 * only scanner can remove the entry from cache.
234 static struct sa_entry *
235 sa_get(struct ll_statahead_info *sai, const struct qstr *qstr)
237 struct sa_entry *entry;
238 int i = sa_hash(qstr->hash);
240 list_for_each_entry(entry, &sai->sai_cache[i], se_hash) {
241 if (entry->se_qstr.hash == qstr->hash &&
242 entry->se_qstr.len == qstr->len &&
243 memcmp(entry->se_qstr.name, qstr->name, qstr->len) == 0)
249 /* unhash and unlink sa_entry, and then free it */
251 sa_kill(struct ll_statahead_info *sai, struct sa_entry *entry)
253 struct ll_inode_info *lli = ll_i2info(sai->sai_dentry->d_inode);
255 LASSERT(!sa_unhashed(entry));
256 LASSERT(!list_empty(&entry->se_list));
257 LASSERT(sa_ready(entry));
259 sa_unhash(sai, entry);
261 spin_lock(&lli->lli_sa_lock);
262 list_del_init(&entry->se_list);
263 spin_unlock(&lli->lli_sa_lock);
265 iput(entry->se_inode);
270 /* called by scanner after use, sa_entry will be killed */
272 sa_put(struct ll_statahead_info *sai, struct sa_entry *entry)
274 struct sa_entry *tmp, *next;
276 if (entry && entry->se_state == SA_ENTRY_SUCC) {
277 struct ll_sb_info *sbi = ll_i2sbi(sai->sai_dentry->d_inode);
280 sai->sai_consecutive_miss = 0;
281 sai->sai_max = min(2 * sai->sai_max, sbi->ll_sa_max);
284 sai->sai_consecutive_miss++;
291 * kill old completed entries, only scanner process does this, no need
294 list_for_each_entry_safe(tmp, next, &sai->sai_entries, se_list) {
295 if (!is_omitted_entry(sai, tmp->se_index))
302 * update state and sort add entry to sai_entries by index, return true if
303 * scanner is waiting on this entry.
306 __sa_make_ready(struct ll_statahead_info *sai, struct sa_entry *entry, int ret)
309 struct list_head *pos = &sai->sai_entries;
310 __u64 index = entry->se_index;
312 LASSERT(!sa_ready(entry));
313 LASSERT(list_empty(&entry->se_list));
315 list_for_each_entry_reverse(se, &sai->sai_entries, se_list) {
316 if (se->se_index < entry->se_index) {
321 list_add(&entry->se_list, pos);
323 * LU-9210: ll_statahead_interpet must be able to see this before
326 smp_store_release(&entry->se_state,
327 ret < 0 ? SA_ENTRY_INVA : SA_ENTRY_SUCC);
329 return (index == sai->sai_index_wait);
332 /* finish async stat RPC arguments */
333 static void sa_fini_data(struct md_op_item *item)
335 struct md_op_data *op_data = &item->mop_data;
337 if (op_data->op_flags & MF_OPNAME_KMALLOCED)
338 /* allocated via ll_setup_filename called from sa_prep_data */
339 kfree(op_data->op_name);
340 ll_unlock_md_op_lsm(&item->mop_data);
345 static int ll_statahead_interpret(struct req_capsule *pill,
346 struct md_op_item *item, int rc);
349 * prepare arguments for async stat RPC.
351 static struct md_op_item *
352 sa_prep_data(struct inode *dir, struct inode *child, struct sa_entry *entry)
354 struct md_op_item *item;
355 struct ldlm_enqueue_info *einfo;
356 struct md_op_data *op_data;
360 return ERR_PTR(-ENOMEM);
362 op_data = ll_prep_md_op_data(&item->mop_data, dir, child,
363 entry->se_qstr.name, entry->se_qstr.len, 0,
364 LUSTRE_OPC_ANY, NULL);
365 if (IS_ERR(op_data)) {
367 return (struct md_op_item *)op_data;
371 op_data->op_fid2 = entry->se_fid;
373 item->mop_it.it_op = IT_GETATTR;
374 item->mop_dir = igrab(dir);
375 item->mop_cb = ll_statahead_interpret;
376 item->mop_cbdata = entry;
378 einfo = &item->mop_einfo;
379 einfo->ei_type = LDLM_IBITS;
380 einfo->ei_mode = it_to_lock_mode(&item->mop_it);
381 einfo->ei_cb_bl = ll_md_blocking_ast;
382 einfo->ei_cb_cp = ldlm_completion_ast;
383 einfo->ei_cb_gl = NULL;
384 einfo->ei_cbdata = NULL;
385 einfo->ei_req_slot = 1;
391 * release resources used in async stat RPC, update entry state and wakeup if
392 * scanner process it waiting on this entry.
395 sa_make_ready(struct ll_statahead_info *sai, struct sa_entry *entry, int ret)
397 struct ll_inode_info *lli = ll_i2info(sai->sai_dentry->d_inode);
400 spin_lock(&lli->lli_sa_lock);
401 wakeup = __sa_make_ready(sai, entry, ret);
402 spin_unlock(&lli->lli_sa_lock);
405 wake_up(&sai->sai_waitq);
408 /* insert inode into the list of sai_agls */
409 static void ll_agl_add(struct ll_statahead_info *sai,
410 struct inode *inode, int index)
412 struct ll_inode_info *child = ll_i2info(inode);
413 struct ll_inode_info *parent = ll_i2info(sai->sai_dentry->d_inode);
415 spin_lock(&child->lli_agl_lock);
416 if (child->lli_agl_index == 0) {
417 child->lli_agl_index = index;
418 spin_unlock(&child->lli_agl_lock);
420 LASSERT(list_empty(&child->lli_agl_list));
422 spin_lock(&parent->lli_agl_lock);
423 /* Re-check under the lock */
424 if (agl_should_run(sai, inode)) {
425 if (agl_list_empty(sai))
426 wake_up_process(sai->sai_agl_task);
428 list_add_tail(&child->lli_agl_list, &sai->sai_agls);
430 child->lli_agl_index = 0;
431 spin_unlock(&parent->lli_agl_lock);
433 spin_unlock(&child->lli_agl_lock);
438 static struct ll_statahead_info *ll_sai_alloc(struct dentry *dentry)
440 struct ll_statahead_info *sai;
441 struct ll_inode_info *lli = ll_i2info(dentry->d_inode);
450 sai->sai_dentry = dget(dentry);
451 atomic_set(&sai->sai_refcount, 1);
452 sai->sai_max = LL_SA_RPC_MIN;
454 init_waitqueue_head(&sai->sai_waitq);
456 INIT_LIST_HEAD(&sai->sai_entries);
457 INIT_LIST_HEAD(&sai->sai_agls);
459 for (i = 0; i < LL_SA_CACHE_SIZE; i++) {
460 INIT_LIST_HEAD(&sai->sai_cache[i]);
461 spin_lock_init(&sai->sai_cache_lock[i]);
463 atomic_set(&sai->sai_cache_count, 0);
465 spin_lock(&sai_generation_lock);
466 lli->lli_sa_generation = ++sai_generation;
467 if (unlikely(sai_generation == 0))
468 lli->lli_sa_generation = ++sai_generation;
469 spin_unlock(&sai_generation_lock);
475 static inline void ll_sai_free(struct ll_statahead_info *sai)
477 LASSERT(sai->sai_dentry != NULL);
478 dput(sai->sai_dentry);
483 * take refcount of sai if sai for @dir exists, which means statahead is on for
486 static inline struct ll_statahead_info *ll_sai_get(struct inode *dir)
488 struct ll_inode_info *lli = ll_i2info(dir);
489 struct ll_statahead_info *sai = NULL;
491 spin_lock(&lli->lli_sa_lock);
494 atomic_inc(&sai->sai_refcount);
495 spin_unlock(&lli->lli_sa_lock);
501 * put sai refcount after use, if refcount reaches zero, free sai and sa_entries
504 static void ll_sai_put(struct ll_statahead_info *sai)
506 struct ll_inode_info *lli = ll_i2info(sai->sai_dentry->d_inode);
508 if (atomic_dec_and_lock(&sai->sai_refcount, &lli->lli_sa_lock)) {
509 struct sa_entry *entry, *next;
510 struct ll_sb_info *sbi = ll_i2sbi(sai->sai_dentry->d_inode);
513 spin_unlock(&lli->lli_sa_lock);
515 LASSERT(!sai->sai_task);
516 LASSERT(!sai->sai_agl_task);
517 LASSERT(sai->sai_sent == sai->sai_replied);
519 list_for_each_entry_safe(entry, next, &sai->sai_entries,
523 LASSERT(atomic_read(&sai->sai_cache_count) == 0);
524 LASSERT(agl_list_empty(sai));
527 atomic_dec(&sbi->ll_sa_running);
531 /* Do NOT forget to drop inode refcount when into sai_agls. */
532 static void ll_agl_trigger(struct inode *inode, struct ll_statahead_info *sai)
534 struct ll_inode_info *lli = ll_i2info(inode);
535 u64 index = lli->lli_agl_index;
541 LASSERT(list_empty(&lli->lli_agl_list));
543 /* AGL maybe fall behind statahead with one entry */
544 if (is_omitted_entry(sai, index + 1)) {
545 lli->lli_agl_index = 0;
551 * In case of restore, the MDT has the right size and has already
552 * sent it back without granting the layout lock, inode is up-to-date.
553 * Then AGL (async glimpse lock) is useless.
554 * Also to glimpse we need the layout, in case of a runninh restore
555 * the MDT holds the layout lock so the glimpse will block up to the
556 * end of restore (statahead/agl will block)
558 if (test_bit(LLIF_FILE_RESTORING, &lli->lli_flags)) {
559 lli->lli_agl_index = 0;
564 /* Someone is in glimpse (sync or async), do nothing. */
565 rc = down_write_trylock(&lli->lli_glimpse_sem);
567 lli->lli_agl_index = 0;
573 * Someone triggered glimpse within 1 sec before.
574 * 1) The former glimpse succeeded with glimpse lock granted by OST, and
575 * if the lock is still cached on client, AGL needs to do nothing. If
576 * it is cancelled by other client, AGL maybe cannot obtaion new lock
577 * for no glimpse callback triggered by AGL.
578 * 2) The former glimpse succeeded, but OST did not grant glimpse lock.
579 * Under such case, it is quite possible that the OST will not grant
580 * glimpse lock for AGL also.
581 * 3) The former glimpse failed, compared with other two cases, it is
582 * relative rare. AGL can ignore such case, and it will not muchly
583 * affect the performance.
585 expire = ktime_sub_ns(ktime_get(), NSEC_PER_SEC);
586 if (ktime_to_ns(lli->lli_glimpse_time) &&
587 ktime_before(expire, lli->lli_glimpse_time)) {
588 up_write(&lli->lli_glimpse_sem);
589 lli->lli_agl_index = 0;
595 "Handling (init) async glimpse: inode = " DFID", idx = %llu\n",
596 PFID(&lli->lli_fid), index);
599 lli->lli_agl_index = 0;
600 lli->lli_glimpse_time = ktime_get();
601 up_write(&lli->lli_glimpse_sem);
604 "Handled (init) async glimpse: inode= " DFID", idx = %llu, rc = %d\n",
605 PFID(&lli->lli_fid), index, rc);
612 static int ll_statahead_interpret_common(struct inode *dir,
613 struct ll_statahead_info *sai,
614 struct req_capsule *pill,
615 struct lookup_intent *it,
616 struct sa_entry *entry,
617 struct mdt_body *body)
624 child = entry->se_inode;
625 rc = ll_prep_inode(&child, pill, dir->i_sb, it);
629 /* If encryption context was returned by MDT, put it in
630 * inode now to save an extra getxattr.
632 if (body->mbo_valid & OBD_MD_ENCCTX) {
633 void *encctx = req_capsule_server_get(pill, &RMF_FILE_ENCCTX);
634 __u32 encctxlen = req_capsule_get_size(pill, &RMF_FILE_ENCCTX,
639 "server returned encryption ctx for "DFID"\n",
640 PFID(ll_inode2fid(child)));
641 rc = ll_xattr_cache_insert(child,
642 xattr_for_enc(child),
645 CWARN("%s: cannot set enc ctx for "DFID": rc = %d\n",
646 ll_i2sbi(child)->ll_fsname,
647 PFID(ll_inode2fid(child)), rc);
651 CDEBUG(D_READA, "%s: setting %.*s"DFID" l_data to inode %p\n",
652 ll_i2sbi(dir)->ll_fsname, entry->se_qstr.len,
653 entry->se_qstr.name, PFID(ll_inode2fid(child)), child);
654 ll_set_lock_data(ll_i2sbi(dir)->ll_md_exp, child, it, NULL);
656 entry->se_inode = child;
658 if (agl_should_run(sai, child))
659 ll_agl_add(sai, child, entry->se_index);
665 static void ll_statahead_interpret_fini(struct ll_inode_info *lli,
666 struct ll_statahead_info *sai,
667 struct md_op_item *item,
668 struct sa_entry *entry,
669 struct ptlrpc_request *req,
673 * First it will drop ldlm ibits lock refcount by calling
674 * ll_intent_drop_lock() in spite of failures. Do not worry about
675 * calling ll_intent_drop_lock() more than once.
677 ll_intent_release(&item->mop_it);
680 ptlrpc_req_finished(req);
681 sa_make_ready(sai, entry, rc);
683 spin_lock(&lli->lli_sa_lock);
685 spin_unlock(&lli->lli_sa_lock);
688 static void ll_statahead_interpret_work(struct work_struct *data)
690 struct ll_interpret_work *work = container_of(data,
691 struct ll_interpret_work, lpw_work);
692 struct md_op_item *item = work->lpw_item;
693 struct req_capsule *pill = work->lpw_pill;
694 struct inode *dir = item->mop_dir;
695 struct ll_inode_info *lli = ll_i2info(dir);
696 struct ll_statahead_info *sai = lli->lli_sai;
697 struct lookup_intent *it;
698 struct sa_entry *entry;
699 struct mdt_body *body;
705 entry = (struct sa_entry *)item->mop_cbdata;
706 LASSERT(entry->se_handle != 0);
709 body = req_capsule_server_get(pill, &RMF_MDT_BODY);
711 GOTO(out, rc = -EFAULT);
713 child = entry->se_inode;
714 /* revalidate; unlinked and re-created with the same name */
715 if (unlikely(!lu_fid_eq(&item->mop_data.op_fid2, &body->mbo_fid1))) {
717 entry->se_inode = NULL;
720 /* The mdt_body is invalid. Skip this entry */
721 GOTO(out, rc = -EAGAIN);
724 it->it_lock_handle = entry->se_handle;
725 rc = md_revalidate_lock(ll_i2mdexp(dir), it, ll_inode2fid(dir), NULL);
727 GOTO(out, rc = -EAGAIN);
729 LASSERT(it->it_extra_rpc_check == 0);
730 rc = ll_statahead_interpret_common(dir, sai, pill, it, entry, body);
732 ll_statahead_interpret_fini(lli, sai, item, entry, pill->rc_req, rc);
737 * Callback for async stat RPC, this is called in ptlrpcd context. It prepares
738 * the inode and set lock data directly in the ptlrpcd context. It will wake up
739 * the directory listing process if the dentry is the waiting one.
741 static int ll_statahead_interpret(struct req_capsule *pill,
742 struct md_op_item *item, int rc)
744 struct lookup_intent *it = &item->mop_it;
745 struct inode *dir = item->mop_dir;
746 struct ll_inode_info *lli = ll_i2info(dir);
747 struct ll_statahead_info *sai = lli->lli_sai;
748 struct sa_entry *entry = (struct sa_entry *)item->mop_cbdata;
749 struct mdt_body *body;
755 if (it_disposition(it, DISP_LOOKUP_NEG))
759 * because statahead thread will wait for all inflight RPC to finish,
760 * sai should be always valid, no need to refcount
762 LASSERT(sai != NULL);
763 LASSERT(entry != NULL);
765 CDEBUG(D_READA, "sa_entry %.*s rc %d\n",
766 entry->se_qstr.len, entry->se_qstr.name, rc);
771 body = req_capsule_server_get(pill, &RMF_MDT_BODY);
773 GOTO(out, rc = -EFAULT);
775 child = entry->se_inode;
776 /* revalidate; unlinked and re-created with the same name */
777 if (unlikely(!lu_fid_eq(&item->mop_data.op_fid2, &body->mbo_fid1))) {
779 entry->se_inode = NULL;
782 /* The mdt_body is invalid. Skip this entry */
783 GOTO(out, rc = -EAGAIN);
786 entry->se_handle = it->it_lock_handle;
788 * In ptlrpcd context, it is not allowed to generate new RPCs
789 * especially for striped directories.
791 it->it_extra_rpc_check = 1;
792 rc = ll_statahead_interpret_common(dir, sai, pill, it, entry, body);
793 if (rc == -EAGAIN && it->it_extra_rpc_need) {
794 struct ll_interpret_work *work;
797 * release ibits lock ASAP to avoid deadlock when statahead
798 * thread enqueues lock on parent in readdir and another
799 * process enqueues lock on child with parent lock held, eg.
802 handle = it->it_lock_handle;
803 ll_intent_drop_lock(it);
804 ll_unlock_md_op_lsm(&item->mop_data);
805 it->it_extra_rpc_check = 0;
806 it->it_extra_rpc_need = 0;
809 * If the stat-ahead entry is a striped directory, there are two
811 * 1. It can drop the result, let the scanning process do stat()
812 * on the striped directory in synchronous way. By this way, it
813 * can avoid to generate new RPCs to obtain the attributes for
814 * slaves of the striped directory in the ptlrpcd context as it
815 * is dangerous of blocking in ptlrpcd thread.
816 * 2. Use work queue or the separate statahead thread to handle
817 * the extra RPCs (@ll_prep_inode->@lmv_revalidate_slaves).
818 * Here we adopt the second solution.
820 OBD_ALLOC_GFP(work, sizeof(*work), GFP_ATOMIC);
822 GOTO(out, rc = -ENOMEM);
824 INIT_WORK(&work->lpw_work, ll_statahead_interpret_work);
825 work->lpw_item = item;
826 work->lpw_pill = pill;
827 ptlrpc_request_addref(pill->rc_req);
828 schedule_work(&work->lpw_work);
833 ll_statahead_interpret_fini(lli, sai, item, entry, NULL, rc);
837 /* async stat for file not found in dcache */
838 static int sa_lookup(struct inode *dir, struct sa_entry *entry)
840 struct md_op_item *item;
845 item = sa_prep_data(dir, NULL, entry);
847 RETURN(PTR_ERR(item));
849 rc = md_intent_getattr_async(ll_i2mdexp(dir), item);
857 * async stat for file found in dcache, similar to .revalidate
859 * \retval 1 dentry valid, no RPC sent
860 * \retval 0 dentry invalid, will send async stat RPC
861 * \retval negative number upon error
863 static int sa_revalidate(struct inode *dir, struct sa_entry *entry,
864 struct dentry *dentry)
866 struct inode *inode = dentry->d_inode;
867 struct lookup_intent it = { .it_op = IT_GETATTR,
868 .it_lock_handle = 0 };
869 struct md_op_item *item;
874 if (unlikely(!inode))
877 if (d_mountpoint(dentry))
880 item = sa_prep_data(dir, inode, entry);
882 RETURN(PTR_ERR(item));
884 entry->se_inode = igrab(inode);
885 rc = md_revalidate_lock(ll_i2mdexp(dir), &it, ll_inode2fid(inode),
888 entry->se_handle = it.it_lock_handle;
889 ll_intent_release(&it);
894 rc = md_intent_getattr_async(ll_i2mdexp(dir), item);
896 entry->se_inode = NULL;
904 /* async stat for file with @name */
905 static void sa_statahead(struct dentry *parent, const char *name, int len,
906 const struct lu_fid *fid)
908 struct inode *dir = parent->d_inode;
909 struct ll_inode_info *lli = ll_i2info(dir);
910 struct ll_statahead_info *sai = lli->lli_sai;
911 struct dentry *dentry = NULL;
912 struct sa_entry *entry;
917 entry = sa_alloc(parent, sai, sai->sai_index, name, len, fid);
921 dentry = d_lookup(parent, &entry->se_qstr);
923 rc = sa_lookup(dir, entry);
925 rc = sa_revalidate(dir, entry, dentry);
926 if (rc == 1 && agl_should_run(sai, dentry->d_inode))
927 ll_agl_add(sai, dentry->d_inode, entry->se_index);
934 sa_make_ready(sai, entry, rc);
943 /* async glimpse (agl) thread main function */
944 static int ll_agl_thread(void *arg)
946 struct dentry *parent = (struct dentry *)arg;
947 struct inode *dir = parent->d_inode;
948 struct ll_inode_info *plli = ll_i2info(dir);
949 struct ll_inode_info *clli;
951 * We already own this reference, so it is safe to take it
954 struct ll_statahead_info *sai = plli->lli_sai;
958 CDEBUG(D_READA, "agl thread started: sai %p, parent %pd\n",
961 while (({set_current_state(TASK_IDLE);
962 !kthread_should_stop(); })) {
963 spin_lock(&plli->lli_agl_lock);
964 clli = list_first_entry_or_null(&sai->sai_agls,
965 struct ll_inode_info,
968 __set_current_state(TASK_RUNNING);
969 list_del_init(&clli->lli_agl_list);
970 spin_unlock(&plli->lli_agl_lock);
971 ll_agl_trigger(&clli->lli_vfs_inode, sai);
974 spin_unlock(&plli->lli_agl_lock);
978 __set_current_state(TASK_RUNNING);
982 static void ll_stop_agl(struct ll_statahead_info *sai)
984 struct dentry *parent = sai->sai_dentry;
985 struct ll_inode_info *plli = ll_i2info(parent->d_inode);
986 struct ll_inode_info *clli;
987 struct task_struct *agl_task;
989 spin_lock(&plli->lli_agl_lock);
990 agl_task = sai->sai_agl_task;
991 sai->sai_agl_task = NULL;
992 spin_unlock(&plli->lli_agl_lock);
996 CDEBUG(D_READA, "stop agl thread: sai %p pid %u\n",
997 sai, (unsigned int)agl_task->pid);
998 kthread_stop(agl_task);
1000 spin_lock(&plli->lli_agl_lock);
1001 while ((clli = list_first_entry_or_null(&sai->sai_agls,
1002 struct ll_inode_info,
1003 lli_agl_list)) != NULL) {
1004 list_del_init(&clli->lli_agl_list);
1005 spin_unlock(&plli->lli_agl_lock);
1006 clli->lli_agl_index = 0;
1007 iput(&clli->lli_vfs_inode);
1008 spin_lock(&plli->lli_agl_lock);
1010 spin_unlock(&plli->lli_agl_lock);
1011 CDEBUG(D_READA, "agl thread stopped: sai %p, parent %pd\n",
1016 /* start agl thread */
1017 static void ll_start_agl(struct dentry *parent, struct ll_statahead_info *sai)
1019 int node = cfs_cpt_spread_node(cfs_cpt_tab, CFS_CPT_ANY);
1020 struct ll_inode_info *plli;
1021 struct task_struct *task;
1025 CDEBUG(D_READA, "start agl thread: sai %p, parent %pd\n",
1028 plli = ll_i2info(parent->d_inode);
1029 task = kthread_create_on_node(ll_agl_thread, parent, node, "ll_agl_%d",
1030 plli->lli_opendir_pid);
1032 CERROR("can't start ll_agl thread, rc: %ld\n", PTR_ERR(task));
1035 sai->sai_agl_task = task;
1036 atomic_inc(&ll_i2sbi(d_inode(parent))->ll_agl_total);
1037 /* Get an extra reference that the thread holds */
1038 ll_sai_get(d_inode(parent));
1040 wake_up_process(task);
1045 /* statahead thread main function */
1046 static int ll_statahead_thread(void *arg)
1048 struct dentry *parent = (struct dentry *)arg;
1049 struct inode *dir = parent->d_inode;
1050 struct ll_inode_info *lli = ll_i2info(dir);
1051 struct ll_sb_info *sbi = ll_i2sbi(dir);
1052 struct ll_statahead_info *sai = lli->lli_sai;
1054 struct md_op_data *op_data;
1055 struct page *page = NULL;
1061 CDEBUG(D_READA, "statahead thread starting: sai %p, parent %pd\n",
1064 OBD_ALLOC_PTR(op_data);
1066 GOTO(out, rc = -ENOMEM);
1068 while (pos != MDS_DIR_END_OFF && sai->sai_task) {
1069 struct lu_dirpage *dp;
1070 struct lu_dirent *ent;
1072 op_data = ll_prep_md_op_data(op_data, dir, dir, NULL, 0, 0,
1073 LUSTRE_OPC_ANY, dir);
1074 if (IS_ERR(op_data)) {
1075 rc = PTR_ERR(op_data);
1079 page = ll_get_dir_page(dir, op_data, pos, NULL);
1080 ll_unlock_md_op_lsm(op_data);
1084 "error reading dir "DFID" at %llu /%llu opendir_pid = %u: rc = %d\n",
1085 PFID(ll_inode2fid(dir)), pos, sai->sai_index,
1086 lli->lli_opendir_pid, rc);
1090 dp = page_address(page);
1091 for (ent = lu_dirent_start(dp);
1092 ent != NULL && sai->sai_task &&
1094 ent = lu_dirent_next(ent)) {
1099 struct llcrypt_str lltr = LLTR_INIT(NULL, 0);
1101 hash = le64_to_cpu(ent->lde_hash);
1102 if (unlikely(hash < pos))
1104 * Skip until we find target hash value.
1108 namelen = le16_to_cpu(ent->lde_namelen);
1109 if (unlikely(namelen == 0))
1111 * Skip dummy record.
1115 name = ent->lde_name;
1116 if (name[0] == '.') {
1122 } else if (name[1] == '.' && namelen == 2) {
1127 } else if (!sai->sai_ls_all) {
1129 * skip hidden files.
1131 sai->sai_skip_hidden++;
1137 * don't stat-ahead first entry.
1139 if (unlikely(++first == 1))
1142 fid_le_to_cpu(&fid, &ent->lde_fid);
1144 while (({set_current_state(TASK_IDLE);
1145 sai->sai_task; })) {
1146 spin_lock(&lli->lli_agl_lock);
1147 while (sa_sent_full(sai) &&
1148 !agl_list_empty(sai)) {
1149 struct ll_inode_info *clli;
1151 __set_current_state(TASK_RUNNING);
1152 clli = agl_first_entry(sai);
1153 list_del_init(&clli->lli_agl_list);
1154 spin_unlock(&lli->lli_agl_lock);
1156 ll_agl_trigger(&clli->lli_vfs_inode,
1159 spin_lock(&lli->lli_agl_lock);
1161 spin_unlock(&lli->lli_agl_lock);
1163 if (!sa_sent_full(sai))
1167 __set_current_state(TASK_RUNNING);
1169 if (IS_ENCRYPTED(dir)) {
1170 struct llcrypt_str de_name =
1171 LLTR_INIT(ent->lde_name, namelen);
1174 rc = llcrypt_fname_alloc_buffer(dir, NAME_MAX,
1179 fid_le_to_cpu(&fid, &ent->lde_fid);
1180 if (ll_fname_disk_to_usr(dir, 0, 0, &de_name,
1182 llcrypt_fname_free_buffer(&lltr);
1190 sa_statahead(parent, name, namelen, &fid);
1191 llcrypt_fname_free_buffer(&lltr);
1194 pos = le64_to_cpu(dp->ldp_hash_end);
1195 down_read(&lli->lli_lsm_sem);
1196 ll_release_page(dir, page,
1197 le32_to_cpu(dp->ldp_flags) & LDF_COLLIDE);
1198 up_read(&lli->lli_lsm_sem);
1200 if (sa_low_hit(sai)) {
1202 atomic_inc(&sbi->ll_sa_wrong);
1204 "Statahead for dir "DFID" hit ratio too low: hit/miss %llu/%llu, sent/replied %llu/%llu, stoppingstatahead thread: pid %d\n",
1205 PFID(&lli->lli_fid), sai->sai_hit,
1206 sai->sai_miss, sai->sai_sent,
1207 sai->sai_replied, current->pid);
1211 ll_finish_md_op_data(op_data);
1214 spin_lock(&lli->lli_sa_lock);
1215 sai->sai_task = NULL;
1216 lli->lli_sa_enabled = 0;
1217 spin_unlock(&lli->lli_sa_lock);
1221 * statahead is finished, but statahead entries need to be cached, wait
1222 * for file release closedir() call to stop me.
1224 while (({set_current_state(TASK_IDLE);
1225 sai->sai_task; })) {
1228 __set_current_state(TASK_RUNNING);
1235 * wait for inflight statahead RPCs to finish, and then we can free sai
1236 * safely because statahead RPC will access sai data
1238 while (sai->sai_sent != sai->sai_replied)
1239 /* in case we're not woken up, timeout wait */
1242 CDEBUG(D_READA, "%s: statahead thread stopped: sai %p, parent %pd\n",
1243 sbi->ll_fsname, sai, parent);
1245 spin_lock(&lli->lli_sa_lock);
1246 sai->sai_task = NULL;
1247 spin_unlock(&lli->lli_sa_lock);
1248 wake_up(&sai->sai_waitq);
1250 atomic_add(sai->sai_hit, &sbi->ll_sa_hit_total);
1251 atomic_add(sai->sai_miss, &sbi->ll_sa_miss_total);
1258 /* authorize opened dir handle @key to statahead */
1259 void ll_authorize_statahead(struct inode *dir, void *key)
1261 struct ll_inode_info *lli = ll_i2info(dir);
1263 spin_lock(&lli->lli_sa_lock);
1264 if (!lli->lli_opendir_key && !lli->lli_sai) {
1266 * if lli_sai is not NULL, it means previous statahead is not
1267 * finished yet, we'd better not start a new statahead for now.
1269 LASSERT(lli->lli_opendir_pid == 0);
1270 lli->lli_opendir_key = key;
1271 lli->lli_opendir_pid = current->pid;
1272 lli->lli_sa_enabled = 1;
1274 spin_unlock(&lli->lli_sa_lock);
1278 * deauthorize opened dir handle @key to statahead, and notify statahead thread
1279 * to quit if it's running.
1281 void ll_deauthorize_statahead(struct inode *dir, void *key)
1283 struct ll_inode_info *lli = ll_i2info(dir);
1284 struct ll_statahead_info *sai;
1286 LASSERT(lli->lli_opendir_key == key);
1287 LASSERT(lli->lli_opendir_pid != 0);
1289 CDEBUG(D_READA, "deauthorize statahead for "DFID"\n",
1290 PFID(&lli->lli_fid));
1292 spin_lock(&lli->lli_sa_lock);
1293 lli->lli_opendir_key = NULL;
1294 lli->lli_opendir_pid = 0;
1295 lli->lli_sa_enabled = 0;
1297 if (sai && sai->sai_task) {
1299 * statahead thread may not have quit yet because it needs to
1300 * cache entries, now it's time to tell it to quit.
1302 * wake_up_process() provides the necessary barriers
1303 * to pair with set_current_state().
1305 struct task_struct *task = sai->sai_task;
1307 sai->sai_task = NULL;
1308 wake_up_process(task);
1310 spin_unlock(&lli->lli_sa_lock);
1315 * not first dirent, or is "."
1317 LS_NOT_FIRST_DE = 0,
1319 * the first non-hidden dirent
1323 * the first hidden dirent, that is "."
1328 /* file is first dirent under @dir */
1329 static int is_first_dirent(struct inode *dir, struct dentry *dentry)
1331 struct qstr *target = &dentry->d_name;
1332 struct md_op_data *op_data;
1334 struct page *page = NULL;
1335 int rc = LS_NOT_FIRST_DE;
1337 struct llcrypt_str lltr = LLTR_INIT(NULL, 0);
1341 op_data = ll_prep_md_op_data(NULL, dir, dir, NULL, 0, 0,
1342 LUSTRE_OPC_ANY, dir);
1343 if (IS_ERR(op_data))
1344 RETURN(PTR_ERR(op_data));
1346 if (IS_ENCRYPTED(dir)) {
1347 int rc2 = llcrypt_fname_alloc_buffer(dir, NAME_MAX, &lltr);
1354 *FIXME choose the start offset of the readdir
1357 page = ll_get_dir_page(dir, op_data, 0, NULL);
1360 struct lu_dirpage *dp;
1361 struct lu_dirent *ent;
1364 struct ll_inode_info *lli = ll_i2info(dir);
1367 CERROR("%s: reading dir "DFID" at %llu opendir_pid = %u : rc = %d\n",
1368 ll_i2sbi(dir)->ll_fsname,
1369 PFID(ll_inode2fid(dir)), pos,
1370 lli->lli_opendir_pid, rc);
1374 dp = page_address(page);
1375 for (ent = lu_dirent_start(dp); ent != NULL;
1376 ent = lu_dirent_next(ent)) {
1381 hash = le64_to_cpu(ent->lde_hash);
1383 * The ll_get_dir_page() can return any page containing
1384 * the given hash which may be not the start hash.
1386 if (unlikely(hash < pos))
1389 namelen = le16_to_cpu(ent->lde_namelen);
1390 if (unlikely(namelen == 0))
1392 * skip dummy record.
1396 name = ent->lde_name;
1397 if (name[0] == '.') {
1403 else if (name[1] == '.' && namelen == 2)
1414 if (dot_de && target->name[0] != '.') {
1415 CDEBUG(D_READA, "%.*s skip hidden file %.*s\n",
1416 target->len, target->name,
1421 if (IS_ENCRYPTED(dir)) {
1422 struct llcrypt_str de_name =
1423 LLTR_INIT(ent->lde_name, namelen);
1426 fid_le_to_cpu(&fid, &ent->lde_fid);
1427 if (ll_fname_disk_to_usr(dir, 0, 0, &de_name,
1434 if (target->len != namelen ||
1435 memcmp(target->name, name, namelen) != 0)
1436 rc = LS_NOT_FIRST_DE;
1440 rc = LS_FIRST_DOT_DE;
1442 ll_release_page(dir, page, false);
1445 pos = le64_to_cpu(dp->ldp_hash_end);
1446 if (pos == MDS_DIR_END_OFF) {
1448 * End of directory reached.
1450 ll_release_page(dir, page, false);
1454 * chain is exhausted
1455 * Normal case: continue to the next page.
1457 ll_release_page(dir, page, le32_to_cpu(dp->ldp_flags) &
1459 page = ll_get_dir_page(dir, op_data, pos, NULL);
1464 llcrypt_fname_free_buffer(&lltr);
1465 ll_finish_md_op_data(op_data);
1471 * revalidate @dentryp from statahead cache
1473 * \param[in] dir parent directory
1474 * \param[in] sai sai structure
1475 * \param[out] dentryp pointer to dentry which will be revalidated
1476 * \param[in] unplug unplug statahead window only (normally for negative
1478 * \retval 1 on success, dentry is saved in @dentryp
1479 * \retval 0 if revalidation failed (no proper lock on client)
1480 * \retval negative number upon error
1482 static int revalidate_statahead_dentry(struct inode *dir,
1483 struct ll_statahead_info *sai,
1484 struct dentry **dentryp,
1487 struct sa_entry *entry = NULL;
1488 struct ll_inode_info *lli = ll_i2info(dir);
1493 if ((*dentryp)->d_name.name[0] == '.') {
1494 if (sai->sai_ls_all ||
1495 sai->sai_miss_hidden >= sai->sai_skip_hidden) {
1497 * Hidden dentry is the first one, or statahead
1498 * thread does not skip so many hidden dentries
1499 * before "sai_ls_all" enabled as below.
1502 if (!sai->sai_ls_all)
1504 * It maybe because hidden dentry is not
1505 * the first one, "sai_ls_all" was not
1506 * set, then "ls -al" missed. Enable
1507 * "sai_ls_all" for such case.
1509 sai->sai_ls_all = 1;
1512 * Such "getattr" has been skipped before
1513 * "sai_ls_all" enabled as above.
1515 sai->sai_miss_hidden++;
1523 entry = sa_get(sai, &(*dentryp)->d_name);
1525 GOTO(out, rc = -EAGAIN);
1527 if (!sa_ready(entry)) {
1528 spin_lock(&lli->lli_sa_lock);
1529 sai->sai_index_wait = entry->se_index;
1530 spin_unlock(&lli->lli_sa_lock);
1531 rc = wait_event_idle_timeout(sai->sai_waitq, sa_ready(entry),
1532 cfs_time_seconds(30));
1535 * entry may not be ready, so it may be used by inflight
1536 * statahead RPC, don't free it.
1539 GOTO(out, rc = -EAGAIN);
1544 * We need to see the value that was set immediately before we
1547 if (smp_load_acquire(&entry->se_state) == SA_ENTRY_SUCC &&
1549 struct inode *inode = entry->se_inode;
1550 struct lookup_intent it = { .it_op = IT_GETATTR,
1555 rc = md_revalidate_lock(ll_i2mdexp(dir), &it,
1556 ll_inode2fid(inode), &bits);
1558 if (!(*dentryp)->d_inode) {
1559 struct dentry *alias;
1561 alias = ll_splice_alias(inode, *dentryp);
1562 if (IS_ERR(alias)) {
1563 ll_intent_release(&it);
1564 GOTO(out, rc = PTR_ERR(alias));
1568 * statahead prepared this inode, transfer inode
1569 * refcount from sa_entry to dentry
1571 entry->se_inode = NULL;
1572 } else if ((*dentryp)->d_inode != inode) {
1573 /* revalidate, but inode is recreated */
1575 "%s: stale dentry %pd inode " DFID", statahead inode "DFID "\n",
1576 ll_i2sbi(inode)->ll_fsname, *dentryp,
1577 PFID(ll_inode2fid((*dentryp)->d_inode)),
1578 PFID(ll_inode2fid(inode)));
1579 ll_intent_release(&it);
1580 GOTO(out, rc = -ESTALE);
1583 if ((bits & MDS_INODELOCK_LOOKUP) &&
1584 d_lustre_invalid(*dentryp)) {
1585 d_lustre_revalidate(*dentryp);
1586 ll_update_dir_depth(dir, (*dentryp)->d_inode);
1589 ll_intent_release(&it);
1594 * statahead cached sa_entry can be used only once, and will be killed
1595 * right after use, so if lookup/revalidate accessed statahead cache,
1596 * set dentry ldd_sa_generation to parent lli_sa_generation, later if we
1597 * stat this file again, we know we've done statahead before, see
1598 * dentry_may_statahead().
1600 if (lld_is_init(*dentryp))
1601 ll_d2d(*dentryp)->lld_sa_generation = lli->lli_sa_generation;
1603 spin_lock(&lli->lli_sa_lock);
1605 wake_up_process(sai->sai_task);
1606 spin_unlock(&lli->lli_sa_lock);
1612 * start statahead thread
1614 * \param[in] dir parent directory
1615 * \param[in] dentry dentry that triggers statahead, normally the first
1617 * \param[in] agl indicate whether AGL is needed
1618 * \retval -EAGAIN on success, because when this function is
1619 * called, it's already in lookup call, so client should
1620 * do it itself instead of waiting for statahead thread
1621 * to do it asynchronously.
1622 * \retval negative number upon error
1624 static int start_statahead_thread(struct inode *dir, struct dentry *dentry,
1627 int node = cfs_cpt_spread_node(cfs_cpt_tab, CFS_CPT_ANY);
1628 struct ll_inode_info *lli = ll_i2info(dir);
1629 struct ll_statahead_info *sai = NULL;
1630 struct dentry *parent = dentry->d_parent;
1631 struct task_struct *task;
1632 struct ll_sb_info *sbi = ll_i2sbi(parent->d_inode);
1633 int first = LS_FIRST_DE;
1638 /* I am the "lli_opendir_pid" owner, only me can set "lli_sai". */
1639 first = is_first_dirent(dir, dentry);
1640 if (first == LS_NOT_FIRST_DE)
1641 /* It is not "ls -{a}l" operation, no need statahead for it. */
1642 GOTO(out, rc = -EFAULT);
1644 if (unlikely(atomic_inc_return(&sbi->ll_sa_running) >
1645 sbi->ll_sa_running_max)) {
1647 "Too many concurrent statahead instances, avoid new statahead instance temporarily.\n");
1648 GOTO(out, rc = -EMFILE);
1651 sai = ll_sai_alloc(parent);
1653 GOTO(out, rc = -ENOMEM);
1655 sai->sai_ls_all = (first == LS_FIRST_DOT_DE);
1658 * if current lli_opendir_key was deauthorized, or dir re-opened by
1659 * another process, don't start statahead, otherwise the newly spawned
1660 * statahead thread won't be notified to quit.
1662 spin_lock(&lli->lli_sa_lock);
1663 if (unlikely(lli->lli_sai || !lli->lli_opendir_key ||
1664 lli->lli_opendir_pid != current->pid)) {
1665 spin_unlock(&lli->lli_sa_lock);
1666 GOTO(out, rc = -EPERM);
1669 spin_unlock(&lli->lli_sa_lock);
1671 CDEBUG(D_READA, "start statahead thread: [pid %d] [parent %pd]\n",
1672 current->pid, parent);
1674 task = kthread_create_on_node(ll_statahead_thread, parent, node,
1675 "ll_sa_%u", lli->lli_opendir_pid);
1677 spin_lock(&lli->lli_sa_lock);
1678 lli->lli_sai = NULL;
1679 spin_unlock(&lli->lli_sa_lock);
1681 CERROR("can't start ll_sa thread, rc: %d\n", rc);
1685 if (test_bit(LL_SBI_AGL_ENABLED, ll_i2sbi(parent->d_inode)->ll_flags) &&
1687 ll_start_agl(parent, sai);
1689 atomic_inc(&ll_i2sbi(parent->d_inode)->ll_sa_total);
1690 sai->sai_task = task;
1692 wake_up_process(task);
1694 * We don't stat-ahead for the first dirent since we are already in
1701 * once we start statahead thread failed, disable statahead so that
1702 * subsequent stat won't waste time to try it.
1704 spin_lock(&lli->lli_sa_lock);
1705 if (lli->lli_opendir_pid == current->pid)
1706 lli->lli_sa_enabled = 0;
1707 spin_unlock(&lli->lli_sa_lock);
1711 if (first != LS_NOT_FIRST_DE)
1712 atomic_dec(&sbi->ll_sa_running);
1718 * Check whether statahead for @dir was started.
1720 static inline bool ll_statahead_started(struct inode *dir, bool agl)
1722 struct ll_inode_info *lli = ll_i2info(dir);
1723 struct ll_statahead_info *sai;
1725 spin_lock(&lli->lli_sa_lock);
1727 if (sai && (sai->sai_agl_task != NULL) != agl)
1729 "%s: Statahead AGL hint changed from %d to %d\n",
1730 ll_i2sbi(dir)->ll_fsname,
1731 sai->sai_agl_task != NULL, agl);
1732 spin_unlock(&lli->lli_sa_lock);
1738 * statahead entry function, this is called when client getattr on a file, it
1739 * will start statahead thread if this is the first dir entry, else revalidate
1740 * dentry from statahead cache.
1742 * \param[in] dir parent directory
1743 * \param[out] dentryp dentry to getattr
1744 * \param[in] agl whether start the agl thread
1746 * \retval 1 on success
1747 * \retval 0 revalidation from statahead cache failed, caller needs
1748 * to getattr from server directly
1749 * \retval negative number on error, caller often ignores this and
1750 * then getattr from server
1752 int ll_start_statahead(struct inode *dir, struct dentry *dentry, bool agl)
1754 if (!ll_statahead_started(dir, agl))
1755 return start_statahead_thread(dir, dentry, agl);
1760 * revalidate dentry from statahead cache.
1762 * \param[in] dir parent directory
1763 * \param[out] dentryp dentry to getattr
1764 * \param[in] unplug unplug statahead window only (normally for negative
1766 * \retval 1 on success
1767 * \retval 0 revalidation from statahead cache failed, caller needs
1768 * to getattr from server directly
1769 * \retval negative number on error, caller often ignores this and
1770 * then getattr from server
1772 int ll_revalidate_statahead(struct inode *dir, struct dentry **dentryp,
1775 struct ll_statahead_info *sai;
1778 sai = ll_sai_get(dir);
1780 rc = revalidate_statahead_dentry(dir, sai, dentryp, unplug);
1781 CDEBUG(D_READA, "revalidate statahead %pd: rc = %d.\n",