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 add it into
58 * sai_interim_entries, later statahead thread will call sa_handle_callback() to
59 * instantiate entry and move it into sai_entries, and then only scanner process
60 * can access and free it.
63 /* link into sai_interim_entries or sai_entries */
64 struct list_head se_list;
65 /* link into sai hash table locally */
66 struct list_head se_hash;
67 /* entry index in the sai */
69 /* low layer ldlm lock handle */
73 /* entry size, contains name */
75 /* pointer to async getattr enqueue info */
76 struct md_enqueue_info *se_minfo;
77 /* pointer to the async getattr request */
78 struct ptlrpc_request *se_req;
79 /* pointer to the target inode */
80 struct inode *se_inode;
87 static unsigned int sai_generation;
88 static DEFINE_SPINLOCK(sai_generation_lock);
90 static inline int sa_unhashed(struct sa_entry *entry)
92 return list_empty(&entry->se_hash);
95 /* sa_entry is ready to use */
96 static inline int sa_ready(struct sa_entry *entry)
98 /* Make sure sa_entry is updated and ready to use */
100 return (entry->se_state != SA_ENTRY_INIT);
103 /* hash value to put in sai_cache */
104 static inline int sa_hash(int val)
106 return val & LL_SA_CACHE_MASK;
109 /* hash entry into sai_cache */
111 sa_rehash(struct ll_statahead_info *sai, struct sa_entry *entry)
113 int i = sa_hash(entry->se_qstr.hash);
115 spin_lock(&sai->sai_cache_lock[i]);
116 list_add_tail(&entry->se_hash, &sai->sai_cache[i]);
117 spin_unlock(&sai->sai_cache_lock[i]);
120 /* unhash entry from sai_cache */
122 sa_unhash(struct ll_statahead_info *sai, struct sa_entry *entry)
124 int i = sa_hash(entry->se_qstr.hash);
126 spin_lock(&sai->sai_cache_lock[i]);
127 list_del_init(&entry->se_hash);
128 spin_unlock(&sai->sai_cache_lock[i]);
131 static inline int agl_should_run(struct ll_statahead_info *sai,
134 return inode && S_ISREG(inode->i_mode) && sai->sai_agl_task;
137 static inline struct ll_inode_info *
138 agl_first_entry(struct ll_statahead_info *sai)
140 return list_first_entry(&sai->sai_agls, struct ll_inode_info,
144 /* statahead window is full */
145 static inline int sa_sent_full(struct ll_statahead_info *sai)
147 return atomic_read(&sai->sai_cache_count) >= sai->sai_max;
150 /* got async stat replies */
151 static inline int sa_has_callback(struct ll_statahead_info *sai)
153 return !list_empty(&sai->sai_interim_entries);
156 static inline int agl_list_empty(struct ll_statahead_info *sai)
158 return list_empty(&sai->sai_agls);
162 * (1) hit ratio less than 80%
164 * (2) consecutive miss more than 8
165 * then means low hit.
167 static inline int sa_low_hit(struct ll_statahead_info *sai)
169 return ((sai->sai_hit > 7 && sai->sai_hit < 4 * sai->sai_miss) ||
170 (sai->sai_consecutive_miss > 8));
174 * if the given index is behind of statahead window more than
175 * SA_OMITTED_ENTRY_MAX, then it is old.
177 static inline int is_omitted_entry(struct ll_statahead_info *sai, __u64 index)
179 return ((__u64)sai->sai_max + index + SA_OMITTED_ENTRY_MAX <
183 /* allocate sa_entry and hash it to allow scanner process to find it */
184 static struct sa_entry *
185 sa_alloc(struct dentry *parent, struct ll_statahead_info *sai, __u64 index,
186 const char *name, int len, const struct lu_fid *fid)
188 struct ll_inode_info *lli;
189 struct sa_entry *entry;
195 entry_size = sizeof(struct sa_entry) + (len & ~3) + 4;
196 OBD_ALLOC(entry, entry_size);
197 if (unlikely(!entry))
198 RETURN(ERR_PTR(-ENOMEM));
200 CDEBUG(D_READA, "alloc sa entry %.*s(%p) index %llu\n",
201 len, name, entry, index);
203 entry->se_index = index;
205 entry->se_state = SA_ENTRY_INIT;
206 entry->se_size = entry_size;
207 dname = (char *)entry + sizeof(struct sa_entry);
208 memcpy(dname, name, len);
210 entry->se_qstr.hash = ll_full_name_hash(parent, name, len);
211 entry->se_qstr.len = len;
212 entry->se_qstr.name = dname;
213 entry->se_fid = *fid;
215 lli = ll_i2info(sai->sai_dentry->d_inode);
217 spin_lock(&lli->lli_sa_lock);
218 INIT_LIST_HEAD(&entry->se_list);
219 sa_rehash(sai, entry);
220 spin_unlock(&lli->lli_sa_lock);
222 atomic_inc(&sai->sai_cache_count);
227 /* free sa_entry, which should have been unhashed and not in any list */
228 static void sa_free(struct ll_statahead_info *sai, struct sa_entry *entry)
230 CDEBUG(D_READA, "free sa entry %.*s(%p) index %llu\n",
231 entry->se_qstr.len, entry->se_qstr.name, entry,
234 LASSERT(list_empty(&entry->se_list));
235 LASSERT(sa_unhashed(entry));
237 OBD_FREE(entry, entry->se_size);
238 atomic_dec(&sai->sai_cache_count);
242 * find sa_entry by name, used by directory scanner, lock is not needed because
243 * only scanner can remove the entry from cache.
245 static struct sa_entry *
246 sa_get(struct ll_statahead_info *sai, const struct qstr *qstr)
248 struct sa_entry *entry;
249 int i = sa_hash(qstr->hash);
251 list_for_each_entry(entry, &sai->sai_cache[i], se_hash) {
252 if (entry->se_qstr.hash == qstr->hash &&
253 entry->se_qstr.len == qstr->len &&
254 memcmp(entry->se_qstr.name, qstr->name, qstr->len) == 0)
260 /* unhash and unlink sa_entry, and then free it */
262 sa_kill(struct ll_statahead_info *sai, struct sa_entry *entry)
264 struct ll_inode_info *lli = ll_i2info(sai->sai_dentry->d_inode);
266 LASSERT(!sa_unhashed(entry));
267 LASSERT(!list_empty(&entry->se_list));
268 LASSERT(sa_ready(entry));
270 sa_unhash(sai, entry);
272 spin_lock(&lli->lli_sa_lock);
273 list_del_init(&entry->se_list);
274 spin_unlock(&lli->lli_sa_lock);
276 iput(entry->se_inode);
281 /* called by scanner after use, sa_entry will be killed */
283 sa_put(struct ll_statahead_info *sai, struct sa_entry *entry)
285 struct sa_entry *tmp, *next;
287 if (entry && entry->se_state == SA_ENTRY_SUCC) {
288 struct ll_sb_info *sbi = ll_i2sbi(sai->sai_dentry->d_inode);
291 sai->sai_consecutive_miss = 0;
292 sai->sai_max = min(2 * sai->sai_max, sbi->ll_sa_max);
295 sai->sai_consecutive_miss++;
302 * kill old completed entries, only scanner process does this, no need
305 list_for_each_entry_safe(tmp, next, &sai->sai_entries, se_list) {
306 if (!is_omitted_entry(sai, tmp->se_index))
313 * update state and sort add entry to sai_entries by index, return true if
314 * scanner is waiting on this entry.
317 __sa_make_ready(struct ll_statahead_info *sai, struct sa_entry *entry, int ret)
320 struct list_head *pos = &sai->sai_entries;
321 __u64 index = entry->se_index;
323 LASSERT(!sa_ready(entry));
324 LASSERT(list_empty(&entry->se_list));
326 list_for_each_entry_reverse(se, &sai->sai_entries, se_list) {
327 if (se->se_index < entry->se_index) {
332 list_add(&entry->se_list, pos);
334 * LU-9210: ll_statahead_interpet must be able to see this before
337 smp_store_release(&entry->se_state,
338 ret < 0 ? SA_ENTRY_INVA : SA_ENTRY_SUCC);
340 return (index == sai->sai_index_wait);
343 /* finish async stat RPC arguments */
344 static void sa_fini_data(struct md_enqueue_info *minfo)
346 struct md_op_data *op_data = &minfo->mi_data;
348 if (op_data->op_flags & MF_OPNAME_KMALLOCED)
349 /* allocated via ll_setup_filename called from sa_prep_data */
350 kfree(op_data->op_name);
351 ll_unlock_md_op_lsm(&minfo->mi_data);
356 static int ll_statahead_interpret(struct ptlrpc_request *req,
357 struct md_enqueue_info *minfo, int rc);
360 * prepare arguments for async stat RPC.
362 static struct md_enqueue_info *
363 sa_prep_data(struct inode *dir, struct inode *child, struct sa_entry *entry)
365 struct md_enqueue_info *minfo;
366 struct ldlm_enqueue_info *einfo;
367 struct md_op_data *op_data;
369 OBD_ALLOC_PTR(minfo);
371 return ERR_PTR(-ENOMEM);
373 op_data = ll_prep_md_op_data(&minfo->mi_data, dir, child,
374 entry->se_qstr.name, entry->se_qstr.len, 0,
375 LUSTRE_OPC_ANY, NULL);
376 if (IS_ERR(op_data)) {
378 return (struct md_enqueue_info *)op_data;
382 op_data->op_fid2 = entry->se_fid;
384 minfo->mi_it.it_op = IT_GETATTR;
385 minfo->mi_dir = igrab(dir);
386 minfo->mi_cb = ll_statahead_interpret;
387 minfo->mi_cbdata = entry;
389 einfo = &minfo->mi_einfo;
390 einfo->ei_type = LDLM_IBITS;
391 einfo->ei_mode = it_to_lock_mode(&minfo->mi_it);
392 einfo->ei_cb_bl = ll_md_blocking_ast;
393 einfo->ei_cb_cp = ldlm_completion_ast;
394 einfo->ei_cb_gl = NULL;
395 einfo->ei_cbdata = NULL;
396 einfo->ei_req_slot = 1;
402 * release resources used in async stat RPC, update entry state and wakeup if
403 * scanner process it waiting on this entry.
406 sa_make_ready(struct ll_statahead_info *sai, struct sa_entry *entry, int ret)
408 struct ll_inode_info *lli = ll_i2info(sai->sai_dentry->d_inode);
409 struct md_enqueue_info *minfo = entry->se_minfo;
410 struct ptlrpc_request *req = entry->se_req;
413 /* release resources used in RPC */
415 entry->se_minfo = NULL;
416 ll_intent_release(&minfo->mi_it);
421 entry->se_req = NULL;
422 ptlrpc_req_finished(req);
425 spin_lock(&lli->lli_sa_lock);
426 wakeup = __sa_make_ready(sai, entry, ret);
427 spin_unlock(&lli->lli_sa_lock);
430 wake_up(&sai->sai_waitq);
433 /* insert inode into the list of sai_agls */
434 static void ll_agl_add(struct ll_statahead_info *sai,
435 struct inode *inode, int index)
437 struct ll_inode_info *child = ll_i2info(inode);
438 struct ll_inode_info *parent = ll_i2info(sai->sai_dentry->d_inode);
440 spin_lock(&child->lli_agl_lock);
441 if (child->lli_agl_index == 0) {
442 child->lli_agl_index = index;
443 spin_unlock(&child->lli_agl_lock);
445 LASSERT(list_empty(&child->lli_agl_list));
447 spin_lock(&parent->lli_agl_lock);
448 /* Re-check under the lock */
449 if (agl_should_run(sai, inode)) {
450 if (agl_list_empty(sai))
451 wake_up_process(sai->sai_agl_task);
453 list_add_tail(&child->lli_agl_list, &sai->sai_agls);
455 child->lli_agl_index = 0;
456 spin_unlock(&parent->lli_agl_lock);
458 spin_unlock(&child->lli_agl_lock);
463 static struct ll_statahead_info *ll_sai_alloc(struct dentry *dentry)
465 struct ll_statahead_info *sai;
466 struct ll_inode_info *lli = ll_i2info(dentry->d_inode);
475 sai->sai_dentry = dget(dentry);
476 atomic_set(&sai->sai_refcount, 1);
477 sai->sai_max = LL_SA_RPC_MIN;
479 init_waitqueue_head(&sai->sai_waitq);
481 INIT_LIST_HEAD(&sai->sai_interim_entries);
482 INIT_LIST_HEAD(&sai->sai_entries);
483 INIT_LIST_HEAD(&sai->sai_agls);
485 for (i = 0; i < LL_SA_CACHE_SIZE; i++) {
486 INIT_LIST_HEAD(&sai->sai_cache[i]);
487 spin_lock_init(&sai->sai_cache_lock[i]);
489 atomic_set(&sai->sai_cache_count, 0);
491 spin_lock(&sai_generation_lock);
492 lli->lli_sa_generation = ++sai_generation;
493 if (unlikely(sai_generation == 0))
494 lli->lli_sa_generation = ++sai_generation;
495 spin_unlock(&sai_generation_lock);
501 static inline void ll_sai_free(struct ll_statahead_info *sai)
503 LASSERT(sai->sai_dentry != NULL);
504 dput(sai->sai_dentry);
509 * take refcount of sai if sai for @dir exists, which means statahead is on for
512 static inline struct ll_statahead_info *ll_sai_get(struct inode *dir)
514 struct ll_inode_info *lli = ll_i2info(dir);
515 struct ll_statahead_info *sai = NULL;
517 spin_lock(&lli->lli_sa_lock);
520 atomic_inc(&sai->sai_refcount);
521 spin_unlock(&lli->lli_sa_lock);
527 * put sai refcount after use, if refcount reaches zero, free sai and sa_entries
530 static void ll_sai_put(struct ll_statahead_info *sai)
532 struct ll_inode_info *lli = ll_i2info(sai->sai_dentry->d_inode);
534 if (atomic_dec_and_lock(&sai->sai_refcount, &lli->lli_sa_lock)) {
535 struct sa_entry *entry, *next;
536 struct ll_sb_info *sbi = ll_i2sbi(sai->sai_dentry->d_inode);
539 spin_unlock(&lli->lli_sa_lock);
541 LASSERT(!sai->sai_task);
542 LASSERT(!sai->sai_agl_task);
543 LASSERT(sai->sai_sent == sai->sai_replied);
544 LASSERT(!sa_has_callback(sai));
546 list_for_each_entry_safe(entry, next, &sai->sai_entries,
550 LASSERT(atomic_read(&sai->sai_cache_count) == 0);
551 LASSERT(agl_list_empty(sai));
554 atomic_dec(&sbi->ll_sa_running);
558 /* Do NOT forget to drop inode refcount when into sai_agls. */
559 static void ll_agl_trigger(struct inode *inode, struct ll_statahead_info *sai)
561 struct ll_inode_info *lli = ll_i2info(inode);
562 u64 index = lli->lli_agl_index;
568 LASSERT(list_empty(&lli->lli_agl_list));
570 /* AGL maybe fall behind statahead with one entry */
571 if (is_omitted_entry(sai, index + 1)) {
572 lli->lli_agl_index = 0;
578 * In case of restore, the MDT has the right size and has already
579 * sent it back without granting the layout lock, inode is up-to-date.
580 * Then AGL (async glimpse lock) is useless.
581 * Also to glimpse we need the layout, in case of a runninh restore
582 * the MDT holds the layout lock so the glimpse will block up to the
583 * end of restore (statahead/agl will block)
585 if (test_bit(LLIF_FILE_RESTORING, &lli->lli_flags)) {
586 lli->lli_agl_index = 0;
591 /* Someone is in glimpse (sync or async), do nothing. */
592 rc = down_write_trylock(&lli->lli_glimpse_sem);
594 lli->lli_agl_index = 0;
600 * Someone triggered glimpse within 1 sec before.
601 * 1) The former glimpse succeeded with glimpse lock granted by OST, and
602 * if the lock is still cached on client, AGL needs to do nothing. If
603 * it is cancelled by other client, AGL maybe cannot obtaion new lock
604 * for no glimpse callback triggered by AGL.
605 * 2) The former glimpse succeeded, but OST did not grant glimpse lock.
606 * Under such case, it is quite possible that the OST will not grant
607 * glimpse lock for AGL also.
608 * 3) The former glimpse failed, compared with other two cases, it is
609 * relative rare. AGL can ignore such case, and it will not muchly
610 * affect the performance.
612 expire = ktime_sub_ns(ktime_get(), NSEC_PER_SEC);
613 if (ktime_to_ns(lli->lli_glimpse_time) &&
614 ktime_before(expire, lli->lli_glimpse_time)) {
615 up_write(&lli->lli_glimpse_sem);
616 lli->lli_agl_index = 0;
622 "Handling (init) async glimpse: inode = " DFID", idx = %llu\n",
623 PFID(&lli->lli_fid), index);
626 lli->lli_agl_index = 0;
627 lli->lli_glimpse_time = ktime_get();
628 up_write(&lli->lli_glimpse_sem);
631 "Handled (init) async glimpse: inode= " DFID", idx = %llu, rc = %d\n",
632 PFID(&lli->lli_fid), index, rc);
640 * prepare inode for sa entry, add it into agl list, now sa_entry is ready
641 * to be used by scanner process.
643 static void sa_instantiate(struct ll_statahead_info *sai,
644 struct sa_entry *entry)
646 struct inode *dir = sai->sai_dentry->d_inode;
648 struct md_enqueue_info *minfo;
649 struct lookup_intent *it;
650 struct ptlrpc_request *req;
651 struct mdt_body *body;
656 LASSERT(entry->se_handle != 0);
658 minfo = entry->se_minfo;
661 body = req_capsule_server_get(&req->rq_pill, &RMF_MDT_BODY);
663 GOTO(out, rc = -EFAULT);
665 child = entry->se_inode;
666 /* revalidate; unlinked and re-created with the same name */
667 if (unlikely(!lu_fid_eq(&minfo->mi_data.op_fid2, &body->mbo_fid1))) {
669 entry->se_inode = NULL;
672 /* The mdt_body is invalid. Skip this entry */
673 GOTO(out, rc = -EAGAIN);
676 it->it_lock_handle = entry->se_handle;
677 rc = md_revalidate_lock(ll_i2mdexp(dir), it, ll_inode2fid(dir), NULL);
679 GOTO(out, rc = -EAGAIN);
681 rc = ll_prep_inode(&child, &req->rq_pill, dir->i_sb, it);
685 /* If encryption context was returned by MDT, put it in
686 * inode now to save an extra getxattr.
688 if (body->mbo_valid & OBD_MD_ENCCTX) {
689 void *encctx = req_capsule_server_get(&req->rq_pill,
691 __u32 encctxlen = req_capsule_get_size(&req->rq_pill,
697 "server returned encryption ctx for "DFID"\n",
698 PFID(ll_inode2fid(child)));
699 rc = ll_xattr_cache_insert(child,
700 LL_XATTR_NAME_ENCRYPTION_CONTEXT,
703 CWARN("%s: cannot set enc ctx for "DFID": rc = %d\n",
704 ll_i2sbi(child)->ll_fsname,
705 PFID(ll_inode2fid(child)), rc);
709 CDEBUG(D_READA, "%s: setting %.*s"DFID" l_data to inode %p\n",
710 ll_i2sbi(dir)->ll_fsname, entry->se_qstr.len,
711 entry->se_qstr.name, PFID(ll_inode2fid(child)), child);
712 ll_set_lock_data(ll_i2sbi(dir)->ll_md_exp, child, it, NULL);
714 entry->se_inode = child;
716 if (agl_should_run(sai, child))
717 ll_agl_add(sai, child, entry->se_index);
723 * sa_make_ready() will drop ldlm ibits lock refcount by calling
724 * ll_intent_drop_lock() in spite of failures. Do not worry about
725 * calling ll_intent_drop_lock() more than once.
727 sa_make_ready(sai, entry, rc);
730 /* once there are async stat replies, instantiate sa_entry from replies */
731 static void sa_handle_callback(struct ll_statahead_info *sai)
733 struct ll_inode_info *lli;
735 lli = ll_i2info(sai->sai_dentry->d_inode);
737 spin_lock(&lli->lli_sa_lock);
738 while (sa_has_callback(sai)) {
739 struct sa_entry *entry;
741 entry = list_entry(sai->sai_interim_entries.next,
742 struct sa_entry, se_list);
743 list_del_init(&entry->se_list);
744 spin_unlock(&lli->lli_sa_lock);
746 sa_instantiate(sai, entry);
747 spin_lock(&lli->lli_sa_lock);
749 spin_unlock(&lli->lli_sa_lock);
753 * callback for async stat RPC, because this is called in ptlrpcd context, we
754 * only put sa_entry in sai_interim_entries, and wake up statahead thread to
755 * really prepare inode and instantiate sa_entry later.
757 static int ll_statahead_interpret(struct ptlrpc_request *req,
758 struct md_enqueue_info *minfo, int rc)
760 struct lookup_intent *it = &minfo->mi_it;
761 struct inode *dir = minfo->mi_dir;
762 struct ll_inode_info *lli = ll_i2info(dir);
763 struct ll_statahead_info *sai = lli->lli_sai;
764 struct sa_entry *entry = (struct sa_entry *)minfo->mi_cbdata;
769 if (it_disposition(it, DISP_LOOKUP_NEG))
773 * because statahead thread will wait for all inflight RPC to finish,
774 * sai should be always valid, no need to refcount
776 LASSERT(sai != NULL);
777 LASSERT(entry != NULL);
779 CDEBUG(D_READA, "sa_entry %.*s rc %d\n",
780 entry->se_qstr.len, entry->se_qstr.name, rc);
783 ll_intent_release(it);
787 * release ibits lock ASAP to avoid deadlock when statahead
788 * thread enqueues lock on parent in readdir and another
789 * process enqueues lock on child with parent lock held, eg.
792 handle = it->it_lock_handle;
793 ll_intent_drop_lock(it);
794 ll_unlock_md_op_lsm(&minfo->mi_data);
797 spin_lock(&lli->lli_sa_lock);
799 if (__sa_make_ready(sai, entry, rc))
800 wake_up(&sai->sai_waitq);
804 entry->se_minfo = minfo;
805 entry->se_req = ptlrpc_request_addref(req);
807 * Release the async ibits lock ASAP to avoid deadlock
808 * when statahead thread tries to enqueue lock on parent
809 * for readpage and other tries to enqueue lock on child
810 * with parent's lock held, for example: unlink.
812 entry->se_handle = handle;
813 if (!sa_has_callback(sai))
816 list_add_tail(&entry->se_list, &sai->sai_interim_entries);
817 if (first && sai->sai_task)
818 wake_up_process(sai->sai_task);
822 spin_unlock(&lli->lli_sa_lock);
827 /* async stat for file not found in dcache */
828 static int sa_lookup(struct inode *dir, struct sa_entry *entry)
830 struct md_enqueue_info *minfo;
835 minfo = sa_prep_data(dir, NULL, entry);
837 RETURN(PTR_ERR(minfo));
839 rc = md_intent_getattr_async(ll_i2mdexp(dir), minfo);
847 * async stat for file found in dcache, similar to .revalidate
849 * \retval 1 dentry valid, no RPC sent
850 * \retval 0 dentry invalid, will send async stat RPC
851 * \retval negative number upon error
853 static int sa_revalidate(struct inode *dir, struct sa_entry *entry,
854 struct dentry *dentry)
856 struct inode *inode = dentry->d_inode;
857 struct lookup_intent it = { .it_op = IT_GETATTR,
858 .it_lock_handle = 0 };
859 struct md_enqueue_info *minfo;
864 if (unlikely(!inode))
867 if (d_mountpoint(dentry))
870 minfo = sa_prep_data(dir, inode, entry);
872 RETURN(PTR_ERR(minfo));
874 entry->se_inode = igrab(inode);
875 rc = md_revalidate_lock(ll_i2mdexp(dir), &it, ll_inode2fid(inode),
878 entry->se_handle = it.it_lock_handle;
879 ll_intent_release(&it);
884 rc = md_intent_getattr_async(ll_i2mdexp(dir), minfo);
886 entry->se_inode = NULL;
894 /* async stat for file with @name */
895 static void sa_statahead(struct dentry *parent, const char *name, int len,
896 const struct lu_fid *fid)
898 struct inode *dir = parent->d_inode;
899 struct ll_inode_info *lli = ll_i2info(dir);
900 struct ll_statahead_info *sai = lli->lli_sai;
901 struct dentry *dentry = NULL;
902 struct sa_entry *entry;
907 entry = sa_alloc(parent, sai, sai->sai_index, name, len, fid);
911 dentry = d_lookup(parent, &entry->se_qstr);
913 rc = sa_lookup(dir, entry);
915 rc = sa_revalidate(dir, entry, dentry);
916 if (rc == 1 && agl_should_run(sai, dentry->d_inode))
917 ll_agl_add(sai, dentry->d_inode, entry->se_index);
924 sa_make_ready(sai, entry, rc);
933 /* async glimpse (agl) thread main function */
934 static int ll_agl_thread(void *arg)
936 struct dentry *parent = (struct dentry *)arg;
937 struct inode *dir = parent->d_inode;
938 struct ll_inode_info *plli = ll_i2info(dir);
939 struct ll_inode_info *clli;
941 * We already own this reference, so it is safe to take it
944 struct ll_statahead_info *sai = plli->lli_sai;
948 CDEBUG(D_READA, "agl thread started: sai %p, parent %pd\n",
951 while (({set_current_state(TASK_IDLE);
952 !kthread_should_stop(); })) {
953 spin_lock(&plli->lli_agl_lock);
954 clli = list_first_entry_or_null(&sai->sai_agls,
955 struct ll_inode_info,
958 __set_current_state(TASK_RUNNING);
959 list_del_init(&clli->lli_agl_list);
960 spin_unlock(&plli->lli_agl_lock);
961 ll_agl_trigger(&clli->lli_vfs_inode, sai);
964 spin_unlock(&plli->lli_agl_lock);
968 __set_current_state(TASK_RUNNING);
972 static void ll_stop_agl(struct ll_statahead_info *sai)
974 struct dentry *parent = sai->sai_dentry;
975 struct ll_inode_info *plli = ll_i2info(parent->d_inode);
976 struct ll_inode_info *clli;
977 struct task_struct *agl_task;
979 spin_lock(&plli->lli_agl_lock);
980 agl_task = sai->sai_agl_task;
981 sai->sai_agl_task = NULL;
982 spin_unlock(&plli->lli_agl_lock);
986 CDEBUG(D_READA, "stop agl thread: sai %p pid %u\n",
987 sai, (unsigned int)agl_task->pid);
988 kthread_stop(agl_task);
990 spin_lock(&plli->lli_agl_lock);
991 while ((clli = list_first_entry_or_null(&sai->sai_agls,
992 struct ll_inode_info,
993 lli_agl_list)) != NULL) {
994 list_del_init(&clli->lli_agl_list);
995 spin_unlock(&plli->lli_agl_lock);
996 clli->lli_agl_index = 0;
997 iput(&clli->lli_vfs_inode);
998 spin_lock(&plli->lli_agl_lock);
1000 spin_unlock(&plli->lli_agl_lock);
1001 CDEBUG(D_READA, "agl thread stopped: sai %p, parent %pd\n",
1006 /* start agl thread */
1007 static void ll_start_agl(struct dentry *parent, struct ll_statahead_info *sai)
1009 int node = cfs_cpt_spread_node(cfs_cpt_tab, CFS_CPT_ANY);
1010 struct ll_inode_info *plli;
1011 struct task_struct *task;
1015 CDEBUG(D_READA, "start agl thread: sai %p, parent %pd\n",
1018 plli = ll_i2info(parent->d_inode);
1019 task = kthread_create_on_node(ll_agl_thread, parent, node, "ll_agl_%d",
1020 plli->lli_opendir_pid);
1022 CERROR("can't start ll_agl thread, rc: %ld\n", PTR_ERR(task));
1025 sai->sai_agl_task = task;
1026 atomic_inc(&ll_i2sbi(d_inode(parent))->ll_agl_total);
1027 /* Get an extra reference that the thread holds */
1028 ll_sai_get(d_inode(parent));
1030 wake_up_process(task);
1035 /* statahead thread main function */
1036 static int ll_statahead_thread(void *arg)
1038 struct dentry *parent = (struct dentry *)arg;
1039 struct inode *dir = parent->d_inode;
1040 struct ll_inode_info *lli = ll_i2info(dir);
1041 struct ll_sb_info *sbi = ll_i2sbi(dir);
1042 struct ll_statahead_info *sai = lli->lli_sai;
1044 struct md_op_data *op_data;
1045 struct page *page = NULL;
1051 CDEBUG(D_READA, "statahead thread starting: sai %p, parent %pd\n",
1054 OBD_ALLOC_PTR(op_data);
1056 GOTO(out, rc = -ENOMEM);
1058 while (pos != MDS_DIR_END_OFF && sai->sai_task) {
1059 struct lu_dirpage *dp;
1060 struct lu_dirent *ent;
1062 op_data = ll_prep_md_op_data(op_data, dir, dir, NULL, 0, 0,
1063 LUSTRE_OPC_ANY, dir);
1064 if (IS_ERR(op_data)) {
1065 rc = PTR_ERR(op_data);
1069 sai->sai_in_readpage = 1;
1070 page = ll_get_dir_page(dir, op_data, pos, NULL);
1071 ll_unlock_md_op_lsm(op_data);
1072 sai->sai_in_readpage = 0;
1076 "error reading dir "DFID" at %llu /%llu opendir_pid = %u: rc = %d\n",
1077 PFID(ll_inode2fid(dir)), pos, sai->sai_index,
1078 lli->lli_opendir_pid, rc);
1082 dp = page_address(page);
1083 for (ent = lu_dirent_start(dp);
1084 ent != NULL && sai->sai_task &&
1086 ent = lu_dirent_next(ent)) {
1091 struct llcrypt_str lltr = LLTR_INIT(NULL, 0);
1093 hash = le64_to_cpu(ent->lde_hash);
1094 if (unlikely(hash < pos))
1096 * Skip until we find target hash value.
1100 namelen = le16_to_cpu(ent->lde_namelen);
1101 if (unlikely(namelen == 0))
1103 * Skip dummy record.
1107 name = ent->lde_name;
1108 if (name[0] == '.') {
1114 } else if (name[1] == '.' && namelen == 2) {
1119 } else if (!sai->sai_ls_all) {
1121 * skip hidden files.
1123 sai->sai_skip_hidden++;
1129 * don't stat-ahead first entry.
1131 if (unlikely(++first == 1))
1134 fid_le_to_cpu(&fid, &ent->lde_fid);
1136 while (({set_current_state(TASK_IDLE);
1137 sai->sai_task; })) {
1138 if (sa_has_callback(sai)) {
1139 __set_current_state(TASK_RUNNING);
1140 sa_handle_callback(sai);
1143 spin_lock(&lli->lli_agl_lock);
1144 while (sa_sent_full(sai) &&
1145 !agl_list_empty(sai)) {
1146 struct ll_inode_info *clli;
1148 __set_current_state(TASK_RUNNING);
1149 clli = agl_first_entry(sai);
1150 list_del_init(&clli->lli_agl_list);
1151 spin_unlock(&lli->lli_agl_lock);
1153 ll_agl_trigger(&clli->lli_vfs_inode,
1156 spin_lock(&lli->lli_agl_lock);
1158 spin_unlock(&lli->lli_agl_lock);
1160 if (!sa_sent_full(sai))
1164 __set_current_state(TASK_RUNNING);
1166 if (IS_ENCRYPTED(dir)) {
1167 struct llcrypt_str de_name =
1168 LLTR_INIT(ent->lde_name, namelen);
1171 rc = llcrypt_fname_alloc_buffer(dir, NAME_MAX,
1176 fid_le_to_cpu(&fid, &ent->lde_fid);
1177 if (ll_fname_disk_to_usr(dir, 0, 0, &de_name,
1179 llcrypt_fname_free_buffer(&lltr);
1187 sa_statahead(parent, name, namelen, &fid);
1188 llcrypt_fname_free_buffer(&lltr);
1191 pos = le64_to_cpu(dp->ldp_hash_end);
1192 ll_release_page(dir, page,
1193 le32_to_cpu(dp->ldp_flags) & LDF_COLLIDE);
1195 if (sa_low_hit(sai)) {
1197 atomic_inc(&sbi->ll_sa_wrong);
1199 "Statahead for dir "DFID" hit ratio too low: hit/miss %llu/%llu, sent/replied %llu/%llu, stoppingstatahead thread: pid %d\n",
1200 PFID(&lli->lli_fid), sai->sai_hit,
1201 sai->sai_miss, sai->sai_sent,
1202 sai->sai_replied, current->pid);
1206 ll_finish_md_op_data(op_data);
1209 spin_lock(&lli->lli_sa_lock);
1210 sai->sai_task = NULL;
1211 lli->lli_sa_enabled = 0;
1212 spin_unlock(&lli->lli_sa_lock);
1216 * statahead is finished, but statahead entries need to be cached, wait
1217 * for file release to stop me.
1219 while (({set_current_state(TASK_IDLE);
1220 sai->sai_task; })) {
1221 if (sa_has_callback(sai)) {
1222 __set_current_state(TASK_RUNNING);
1223 sa_handle_callback(sai);
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 /* release resources held by statahead RPCs */
1243 sa_handle_callback(sai);
1245 CDEBUG(D_READA, "%s: statahead thread stopped: sai %p, parent %pd\n",
1246 sbi->ll_fsname, sai, parent);
1248 spin_lock(&lli->lli_sa_lock);
1249 sai->sai_task = NULL;
1250 spin_unlock(&lli->lli_sa_lock);
1251 wake_up(&sai->sai_waitq);
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 statahead is busy in readdir, help it do post-work */
1528 if (!sa_ready(entry) && sai->sai_in_readpage)
1529 sa_handle_callback(sai);
1531 if (!sa_ready(entry)) {
1532 spin_lock(&lli->lli_sa_lock);
1533 sai->sai_index_wait = entry->se_index;
1534 spin_unlock(&lli->lli_sa_lock);
1535 rc = wait_event_idle_timeout(sai->sai_waitq, sa_ready(entry),
1536 cfs_time_seconds(30));
1539 * entry may not be ready, so it may be used by inflight
1540 * statahead RPC, don't free it.
1543 GOTO(out, rc = -EAGAIN);
1548 * We need to see the value that was set immediately before we
1551 if (smp_load_acquire(&entry->se_state) == SA_ENTRY_SUCC &&
1553 struct inode *inode = entry->se_inode;
1554 struct lookup_intent it = { .it_op = IT_GETATTR,
1559 rc = md_revalidate_lock(ll_i2mdexp(dir), &it,
1560 ll_inode2fid(inode), &bits);
1562 if (!(*dentryp)->d_inode) {
1563 struct dentry *alias;
1565 alias = ll_splice_alias(inode, *dentryp);
1566 if (IS_ERR(alias)) {
1567 ll_intent_release(&it);
1568 GOTO(out, rc = PTR_ERR(alias));
1572 * statahead prepared this inode, transfer inode
1573 * refcount from sa_entry to dentry
1575 entry->se_inode = NULL;
1576 } else if ((*dentryp)->d_inode != inode) {
1577 /* revalidate, but inode is recreated */
1579 "%s: stale dentry %pd inode " DFID", statahead inode "DFID "\n",
1580 ll_i2sbi(inode)->ll_fsname, *dentryp,
1581 PFID(ll_inode2fid((*dentryp)->d_inode)),
1582 PFID(ll_inode2fid(inode)));
1583 ll_intent_release(&it);
1584 GOTO(out, rc = -ESTALE);
1587 if ((bits & MDS_INODELOCK_LOOKUP) &&
1588 d_lustre_invalid(*dentryp)) {
1589 d_lustre_revalidate(*dentryp);
1590 ll_update_dir_depth(dir, (*dentryp)->d_inode);
1593 ll_intent_release(&it);
1598 * statahead cached sa_entry can be used only once, and will be killed
1599 * right after use, so if lookup/revalidate accessed statahead cache,
1600 * set dentry ldd_sa_generation to parent lli_sa_generation, later if we
1601 * stat this file again, we know we've done statahead before, see
1602 * dentry_may_statahead().
1604 if (lld_is_init(*dentryp))
1605 ll_d2d(*dentryp)->lld_sa_generation = lli->lli_sa_generation;
1607 spin_lock(&lli->lli_sa_lock);
1609 wake_up_process(sai->sai_task);
1610 spin_unlock(&lli->lli_sa_lock);
1616 * start statahead thread
1618 * \param[in] dir parent directory
1619 * \param[in] dentry dentry that triggers statahead, normally the first
1621 * \param[in] agl indicate whether AGL is needed
1622 * \retval -EAGAIN on success, because when this function is
1623 * called, it's already in lookup call, so client should
1624 * do it itself instead of waiting for statahead thread
1625 * to do it asynchronously.
1626 * \retval negative number upon error
1628 static int start_statahead_thread(struct inode *dir, struct dentry *dentry,
1631 int node = cfs_cpt_spread_node(cfs_cpt_tab, CFS_CPT_ANY);
1632 struct ll_inode_info *lli = ll_i2info(dir);
1633 struct ll_statahead_info *sai = NULL;
1634 struct dentry *parent = dentry->d_parent;
1635 struct task_struct *task;
1636 struct ll_sb_info *sbi = ll_i2sbi(parent->d_inode);
1637 int first = LS_FIRST_DE;
1642 /* I am the "lli_opendir_pid" owner, only me can set "lli_sai". */
1643 first = is_first_dirent(dir, dentry);
1644 if (first == LS_NOT_FIRST_DE)
1645 /* It is not "ls -{a}l" operation, no need statahead for it. */
1646 GOTO(out, rc = -EFAULT);
1648 if (unlikely(atomic_inc_return(&sbi->ll_sa_running) >
1649 sbi->ll_sa_running_max)) {
1651 "Too many concurrent statahead instances, avoid new statahead instance temporarily.\n");
1652 GOTO(out, rc = -EMFILE);
1655 sai = ll_sai_alloc(parent);
1657 GOTO(out, rc = -ENOMEM);
1659 sai->sai_ls_all = (first == LS_FIRST_DOT_DE);
1662 * if current lli_opendir_key was deauthorized, or dir re-opened by
1663 * another process, don't start statahead, otherwise the newly spawned
1664 * statahead thread won't be notified to quit.
1666 spin_lock(&lli->lli_sa_lock);
1667 if (unlikely(lli->lli_sai || !lli->lli_opendir_key ||
1668 lli->lli_opendir_pid != current->pid)) {
1669 spin_unlock(&lli->lli_sa_lock);
1670 GOTO(out, rc = -EPERM);
1673 spin_unlock(&lli->lli_sa_lock);
1675 CDEBUG(D_READA, "start statahead thread: [pid %d] [parent %pd]\n",
1676 current->pid, parent);
1678 task = kthread_create_on_node(ll_statahead_thread, parent, node,
1679 "ll_sa_%u", lli->lli_opendir_pid);
1681 spin_lock(&lli->lli_sa_lock);
1682 lli->lli_sai = NULL;
1683 spin_unlock(&lli->lli_sa_lock);
1685 CERROR("can't start ll_sa thread, rc: %d\n", rc);
1689 if (test_bit(LL_SBI_AGL_ENABLED, ll_i2sbi(parent->d_inode)->ll_flags) &&
1691 ll_start_agl(parent, sai);
1693 atomic_inc(&ll_i2sbi(parent->d_inode)->ll_sa_total);
1694 sai->sai_task = task;
1696 wake_up_process(task);
1698 * We don't stat-ahead for the first dirent since we are already in
1705 * once we start statahead thread failed, disable statahead so that
1706 * subsequent stat won't waste time to try it.
1708 spin_lock(&lli->lli_sa_lock);
1709 if (lli->lli_opendir_pid == current->pid)
1710 lli->lli_sa_enabled = 0;
1711 spin_unlock(&lli->lli_sa_lock);
1715 if (first != LS_NOT_FIRST_DE)
1716 atomic_dec(&sbi->ll_sa_running);
1722 * Check whether statahead for @dir was started.
1724 static inline bool ll_statahead_started(struct inode *dir, bool agl)
1726 struct ll_inode_info *lli = ll_i2info(dir);
1727 struct ll_statahead_info *sai;
1729 spin_lock(&lli->lli_sa_lock);
1731 if (sai && (sai->sai_agl_task != NULL) != agl)
1733 "%s: Statahead AGL hint changed from %d to %d\n",
1734 ll_i2sbi(dir)->ll_fsname,
1735 sai->sai_agl_task != NULL, agl);
1736 spin_unlock(&lli->lli_sa_lock);
1742 * statahead entry function, this is called when client getattr on a file, it
1743 * will start statahead thread if this is the first dir entry, else revalidate
1744 * dentry from statahead cache.
1746 * \param[in] dir parent directory
1747 * \param[out] dentryp dentry to getattr
1748 * \param[in] agl whether start the agl thread
1750 * \retval 1 on success
1751 * \retval 0 revalidation from statahead cache failed, caller needs
1752 * to getattr from server directly
1753 * \retval negative number on error, caller often ignores this and
1754 * then getattr from server
1756 int ll_start_statahead(struct inode *dir, struct dentry *dentry, bool agl)
1758 if (!ll_statahead_started(dir, agl))
1759 return start_statahead_thread(dir, dentry, agl);
1764 * revalidate dentry from statahead cache.
1766 * \param[in] dir parent directory
1767 * \param[out] dentryp dentry to getattr
1768 * \param[in] unplug unplug statahead window only (normally for negative
1770 * \retval 1 on success
1771 * \retval 0 revalidation from statahead cache failed, caller needs
1772 * to getattr from server directly
1773 * \retval negative number on error, caller often ignores this and
1774 * then getattr from server
1776 int ll_revalidate_statahead(struct inode *dir, struct dentry **dentryp,
1779 struct ll_statahead_info *sai;
1782 sai = ll_sai_get(dir);
1784 rc = revalidate_statahead_dentry(dir, sai, dentryp, unplug);
1785 CDEBUG(D_READA, "revalidate statahead %pd: rc = %d.\n",