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Merge branch 'x86-microcode-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...
[deliverable/linux.git] / drivers / staging / lustre / lustre / llite / statahead.c
1 /*
2 * GPL HEADER START
3 *
4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 only,
8 * as published by the Free Software Foundation.
9 *
10 * This program is distributed in the hope that it will be useful, but
11 * WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * General Public License version 2 for more details (a copy is included
14 * in the LICENSE file that accompanied this code).
15 *
16 * You should have received a copy of the GNU General Public License
17 * version 2 along with this program; If not, see
18 * http://www.gnu.org/licenses/gpl-2.0.html
19 *
20 * GPL HEADER END
21 */
22 /*
23 * Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
24 * Use is subject to license terms.
25 *
26 * Copyright (c) 2011, 2015, Intel Corporation.
27 */
28 /*
29 * This file is part of Lustre, http://www.lustre.org/
30 * Lustre is a trademark of Sun Microsystems, Inc.
31 */
32
33 #include <linux/fs.h>
34 #include <linux/sched.h>
35 #include <linux/mm.h>
36 #include <linux/highmem.h>
37 #include <linux/pagemap.h>
38
39 #define DEBUG_SUBSYSTEM S_LLITE
40
41 #include "../include/obd_support.h"
42 #include "../include/lustre_lite.h"
43 #include "../include/lustre_dlm.h"
44 #include "llite_internal.h"
45
46 #define SA_OMITTED_ENTRY_MAX 8ULL
47
48 enum se_stat {
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 */
53 SA_ENTRY_DEST = 3, /** entry to be destroyed */
54 };
55
56 struct ll_sa_entry {
57 /* link into sai->sai_entries */
58 struct list_head se_link;
59 /* link into sai->sai_entries_{received,stated} */
60 struct list_head se_list;
61 /* link into sai hash table locally */
62 struct list_head se_hash;
63 /* entry reference count */
64 atomic_t se_refcount;
65 /* entry index in the sai */
66 __u64 se_index;
67 /* low layer ldlm lock handle */
68 __u64 se_handle;
69 /* entry status */
70 enum se_stat se_stat;
71 /* entry size, contains name */
72 int se_size;
73 /* pointer to async getattr enqueue info */
74 struct md_enqueue_info *se_minfo;
75 /* pointer to the async getattr request */
76 struct ptlrpc_request *se_req;
77 /* pointer to the target inode */
78 struct inode *se_inode;
79 /* entry name */
80 struct qstr se_qstr;
81 };
82
83 static unsigned int sai_generation;
84 static DEFINE_SPINLOCK(sai_generation_lock);
85
86 /*
87 * The entry only can be released by the caller, it is necessary to hold lock.
88 */
89 static inline int ll_sa_entry_stated(struct ll_sa_entry *entry)
90 {
91 smp_rmb();
92 return (entry->se_stat != SA_ENTRY_INIT);
93 }
94
95 static inline int ll_sa_entry_hash(int val)
96 {
97 return val & LL_SA_CACHE_MASK;
98 }
99
100 /*
101 * Insert entry to hash SA table.
102 */
103 static inline void
104 ll_sa_entry_enhash(struct ll_statahead_info *sai, struct ll_sa_entry *entry)
105 {
106 int i = ll_sa_entry_hash(entry->se_qstr.hash);
107
108 spin_lock(&sai->sai_cache_lock[i]);
109 list_add_tail(&entry->se_hash, &sai->sai_cache[i]);
110 spin_unlock(&sai->sai_cache_lock[i]);
111 }
112
113 /*
114 * Remove entry from SA table.
115 */
116 static inline void
117 ll_sa_entry_unhash(struct ll_statahead_info *sai, struct ll_sa_entry *entry)
118 {
119 int i = ll_sa_entry_hash(entry->se_qstr.hash);
120
121 spin_lock(&sai->sai_cache_lock[i]);
122 list_del_init(&entry->se_hash);
123 spin_unlock(&sai->sai_cache_lock[i]);
124 }
125
126 static inline int agl_should_run(struct ll_statahead_info *sai,
127 struct inode *inode)
128 {
129 return (inode && S_ISREG(inode->i_mode) && sai->sai_agl_valid);
130 }
131
132 static inline int sa_sent_full(struct ll_statahead_info *sai)
133 {
134 return atomic_read(&sai->sai_cache_count) >= sai->sai_max;
135 }
136
137 static inline int sa_received_empty(struct ll_statahead_info *sai)
138 {
139 return list_empty(&sai->sai_entries_received);
140 }
141
142 static inline int agl_list_empty(struct ll_statahead_info *sai)
143 {
144 return list_empty(&sai->sai_entries_agl);
145 }
146
147 /**
148 * (1) hit ratio less than 80%
149 * or
150 * (2) consecutive miss more than 8
151 * then means low hit.
152 */
153 static inline int sa_low_hit(struct ll_statahead_info *sai)
154 {
155 return ((sai->sai_hit > 7 && sai->sai_hit < 4 * sai->sai_miss) ||
156 (sai->sai_consecutive_miss > 8));
157 }
158
159 /*
160 * If the given index is behind of statahead window more than
161 * SA_OMITTED_ENTRY_MAX, then it is old.
162 */
163 static inline int is_omitted_entry(struct ll_statahead_info *sai, __u64 index)
164 {
165 return ((__u64)sai->sai_max + index + SA_OMITTED_ENTRY_MAX <
166 sai->sai_index);
167 }
168
169 /*
170 * Insert it into sai_entries tail when init.
171 */
172 static struct ll_sa_entry *
173 ll_sa_entry_alloc(struct dentry *parent,
174 struct ll_statahead_info *sai, __u64 index,
175 const char *name, int len)
176 {
177 struct ll_inode_info *lli;
178 struct ll_sa_entry *entry;
179 int entry_size;
180 char *dname;
181
182 entry_size = sizeof(struct ll_sa_entry) + (len & ~3) + 4;
183 entry = kzalloc(entry_size, GFP_NOFS);
184 if (unlikely(!entry))
185 return ERR_PTR(-ENOMEM);
186
187 CDEBUG(D_READA, "alloc sa entry %.*s(%p) index %llu\n",
188 len, name, entry, index);
189
190 entry->se_index = index;
191
192 /*
193 * Statahead entry reference rules:
194 *
195 * 1) When statahead entry is initialized, its reference is set as 2.
196 * One reference is used by the directory scanner. When the scanner
197 * searches the statahead cache for the given name, it can perform
198 * lockless hash lookup (only the scanner can remove entry from hash
199 * list), and once found, it needn't to call "atomic_inc()" for the
200 * entry reference. So the performance is improved. After using the
201 * statahead entry, the scanner will call "atomic_dec()" to drop the
202 * reference held when initialization. If it is the last reference,
203 * the statahead entry will be freed.
204 *
205 * 2) All other threads, including statahead thread and ptlrpcd thread,
206 * when they process the statahead entry, the reference for target
207 * should be held to guarantee the entry will not be released by the
208 * directory scanner. After processing the entry, these threads will
209 * drop the entry reference. If it is the last reference, the entry
210 * will be freed.
211 *
212 * The second reference when initializes the statahead entry is used
213 * by the statahead thread, following the rule 2).
214 */
215 atomic_set(&entry->se_refcount, 2);
216 entry->se_stat = SA_ENTRY_INIT;
217 entry->se_size = entry_size;
218 dname = (char *)entry + sizeof(struct ll_sa_entry);
219 memcpy(dname, name, len);
220 dname[len] = 0;
221
222 entry->se_qstr.hash = full_name_hash(parent, name, len);
223 entry->se_qstr.len = len;
224 entry->se_qstr.name = dname;
225
226 lli = ll_i2info(sai->sai_inode);
227 spin_lock(&lli->lli_sa_lock);
228 list_add_tail(&entry->se_link, &sai->sai_entries);
229 INIT_LIST_HEAD(&entry->se_list);
230 ll_sa_entry_enhash(sai, entry);
231 spin_unlock(&lli->lli_sa_lock);
232
233 atomic_inc(&sai->sai_cache_count);
234
235 return entry;
236 }
237
238 /*
239 * Used by the directory scanner to search entry with name.
240 *
241 * Only the caller can remove the entry from hash, so it is unnecessary to hold
242 * hash lock. It is caller's duty to release the init refcount on the entry, so
243 * it is also unnecessary to increase refcount on the entry.
244 */
245 static struct ll_sa_entry *
246 ll_sa_entry_get_byname(struct ll_statahead_info *sai, const struct qstr *qstr)
247 {
248 struct ll_sa_entry *entry;
249 int i = ll_sa_entry_hash(qstr->hash);
250
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)
255 return entry;
256 }
257 return NULL;
258 }
259
260 /*
261 * Used by the async getattr request callback to find entry with index.
262 *
263 * Inside lli_sa_lock to prevent others to change the list during the search.
264 * It needs to increase entry refcount before returning to guarantee that the
265 * entry cannot be freed by others.
266 */
267 static struct ll_sa_entry *
268 ll_sa_entry_get_byindex(struct ll_statahead_info *sai, __u64 index)
269 {
270 struct ll_sa_entry *entry;
271
272 list_for_each_entry(entry, &sai->sai_entries, se_link) {
273 if (entry->se_index == index) {
274 LASSERT(atomic_read(&entry->se_refcount) > 0);
275 atomic_inc(&entry->se_refcount);
276 return entry;
277 }
278 if (entry->se_index > index)
279 break;
280 }
281 return NULL;
282 }
283
284 static void ll_sa_entry_cleanup(struct ll_statahead_info *sai,
285 struct ll_sa_entry *entry)
286 {
287 struct md_enqueue_info *minfo = entry->se_minfo;
288 struct ptlrpc_request *req = entry->se_req;
289
290 if (minfo) {
291 entry->se_minfo = NULL;
292 ll_intent_release(&minfo->mi_it);
293 iput(minfo->mi_dir);
294 kfree(minfo);
295 }
296
297 if (req) {
298 entry->se_req = NULL;
299 ptlrpc_req_finished(req);
300 }
301 }
302
303 static void ll_sa_entry_put(struct ll_statahead_info *sai,
304 struct ll_sa_entry *entry)
305 {
306 if (atomic_dec_and_test(&entry->se_refcount)) {
307 CDEBUG(D_READA, "free sa entry %.*s(%p) index %llu\n",
308 entry->se_qstr.len, entry->se_qstr.name, entry,
309 entry->se_index);
310
311 LASSERT(list_empty(&entry->se_link));
312 LASSERT(list_empty(&entry->se_list));
313 LASSERT(list_empty(&entry->se_hash));
314
315 ll_sa_entry_cleanup(sai, entry);
316 iput(entry->se_inode);
317
318 kfree(entry);
319 atomic_dec(&sai->sai_cache_count);
320 }
321 }
322
323 static inline void
324 do_sa_entry_fini(struct ll_statahead_info *sai, struct ll_sa_entry *entry)
325 {
326 struct ll_inode_info *lli = ll_i2info(sai->sai_inode);
327
328 LASSERT(!list_empty(&entry->se_hash));
329 LASSERT(!list_empty(&entry->se_link));
330
331 ll_sa_entry_unhash(sai, entry);
332
333 spin_lock(&lli->lli_sa_lock);
334 entry->se_stat = SA_ENTRY_DEST;
335 list_del_init(&entry->se_link);
336 if (likely(!list_empty(&entry->se_list)))
337 list_del_init(&entry->se_list);
338 spin_unlock(&lli->lli_sa_lock);
339
340 ll_sa_entry_put(sai, entry);
341 }
342
343 /*
344 * Delete it from sai_entries_stated list when fini.
345 */
346 static void
347 ll_sa_entry_fini(struct ll_statahead_info *sai, struct ll_sa_entry *entry)
348 {
349 struct ll_sa_entry *pos, *next;
350
351 if (entry)
352 do_sa_entry_fini(sai, entry);
353
354 /* drop old entry, only 'scanner' process does this, no need to lock */
355 list_for_each_entry_safe(pos, next, &sai->sai_entries, se_link) {
356 if (!is_omitted_entry(sai, pos->se_index))
357 break;
358 do_sa_entry_fini(sai, pos);
359 }
360 }
361
362 /*
363 * Inside lli_sa_lock.
364 */
365 static void
366 do_sa_entry_to_stated(struct ll_statahead_info *sai,
367 struct ll_sa_entry *entry, enum se_stat stat)
368 {
369 struct ll_sa_entry *se;
370 struct list_head *pos = &sai->sai_entries_stated;
371
372 if (!list_empty(&entry->se_list))
373 list_del_init(&entry->se_list);
374
375 list_for_each_entry_reverse(se, &sai->sai_entries_stated, se_list) {
376 if (se->se_index < entry->se_index) {
377 pos = &se->se_list;
378 break;
379 }
380 }
381
382 list_add(&entry->se_list, pos);
383 entry->se_stat = stat;
384 }
385
386 /*
387 * Move entry to sai_entries_stated and sort with the index.
388 * \retval 1 -- entry to be destroyed.
389 * \retval 0 -- entry is inserted into stated list.
390 */
391 static int
392 ll_sa_entry_to_stated(struct ll_statahead_info *sai,
393 struct ll_sa_entry *entry, enum se_stat stat)
394 {
395 struct ll_inode_info *lli = ll_i2info(sai->sai_inode);
396 int ret = 1;
397
398 ll_sa_entry_cleanup(sai, entry);
399
400 spin_lock(&lli->lli_sa_lock);
401 if (likely(entry->se_stat != SA_ENTRY_DEST)) {
402 do_sa_entry_to_stated(sai, entry, stat);
403 ret = 0;
404 }
405 spin_unlock(&lli->lli_sa_lock);
406
407 return ret;
408 }
409
410 /*
411 * Insert inode into the list of sai_entries_agl.
412 */
413 static void ll_agl_add(struct ll_statahead_info *sai,
414 struct inode *inode, int index)
415 {
416 struct ll_inode_info *child = ll_i2info(inode);
417 struct ll_inode_info *parent = ll_i2info(sai->sai_inode);
418 int added = 0;
419
420 spin_lock(&child->lli_agl_lock);
421 if (child->lli_agl_index == 0) {
422 child->lli_agl_index = index;
423 spin_unlock(&child->lli_agl_lock);
424
425 LASSERT(list_empty(&child->lli_agl_list));
426
427 igrab(inode);
428 spin_lock(&parent->lli_agl_lock);
429 if (list_empty(&sai->sai_entries_agl))
430 added = 1;
431 list_add_tail(&child->lli_agl_list, &sai->sai_entries_agl);
432 spin_unlock(&parent->lli_agl_lock);
433 } else {
434 spin_unlock(&child->lli_agl_lock);
435 }
436
437 if (added > 0)
438 wake_up(&sai->sai_agl_thread.t_ctl_waitq);
439 }
440
441 static struct ll_statahead_info *ll_sai_alloc(void)
442 {
443 struct ll_statahead_info *sai;
444 int i;
445
446 sai = kzalloc(sizeof(*sai), GFP_NOFS);
447 if (!sai)
448 return NULL;
449
450 atomic_set(&sai->sai_refcount, 1);
451
452 spin_lock(&sai_generation_lock);
453 sai->sai_generation = ++sai_generation;
454 if (unlikely(sai_generation == 0))
455 sai->sai_generation = ++sai_generation;
456 spin_unlock(&sai_generation_lock);
457
458 sai->sai_max = LL_SA_RPC_MIN;
459 sai->sai_index = 1;
460 init_waitqueue_head(&sai->sai_waitq);
461 init_waitqueue_head(&sai->sai_thread.t_ctl_waitq);
462 init_waitqueue_head(&sai->sai_agl_thread.t_ctl_waitq);
463
464 INIT_LIST_HEAD(&sai->sai_entries);
465 INIT_LIST_HEAD(&sai->sai_entries_received);
466 INIT_LIST_HEAD(&sai->sai_entries_stated);
467 INIT_LIST_HEAD(&sai->sai_entries_agl);
468
469 for (i = 0; i < LL_SA_CACHE_SIZE; i++) {
470 INIT_LIST_HEAD(&sai->sai_cache[i]);
471 spin_lock_init(&sai->sai_cache_lock[i]);
472 }
473 atomic_set(&sai->sai_cache_count, 0);
474
475 return sai;
476 }
477
478 static inline struct ll_statahead_info *
479 ll_sai_get(struct ll_statahead_info *sai)
480 {
481 atomic_inc(&sai->sai_refcount);
482 return sai;
483 }
484
485 static void ll_sai_put(struct ll_statahead_info *sai)
486 {
487 struct inode *inode = sai->sai_inode;
488 struct ll_inode_info *lli = ll_i2info(inode);
489
490 if (atomic_dec_and_lock(&sai->sai_refcount, &lli->lli_sa_lock)) {
491 struct ll_sa_entry *entry, *next;
492
493 if (unlikely(atomic_read(&sai->sai_refcount) > 0)) {
494 /* It is race case, the interpret callback just hold
495 * a reference count
496 */
497 spin_unlock(&lli->lli_sa_lock);
498 return;
499 }
500
501 LASSERT(!lli->lli_opendir_key);
502 LASSERT(thread_is_stopped(&sai->sai_thread));
503 LASSERT(thread_is_stopped(&sai->sai_agl_thread));
504
505 lli->lli_sai = NULL;
506 lli->lli_opendir_pid = 0;
507 spin_unlock(&lli->lli_sa_lock);
508
509 if (sai->sai_sent > sai->sai_replied)
510 CDEBUG(D_READA, "statahead for dir "DFID
511 " does not finish: [sent:%llu] [replied:%llu]\n",
512 PFID(&lli->lli_fid),
513 sai->sai_sent, sai->sai_replied);
514
515 list_for_each_entry_safe(entry, next, &sai->sai_entries,
516 se_link)
517 do_sa_entry_fini(sai, entry);
518
519 LASSERT(list_empty(&sai->sai_entries));
520 LASSERT(list_empty(&sai->sai_entries_received));
521 LASSERT(list_empty(&sai->sai_entries_stated));
522
523 LASSERT(atomic_read(&sai->sai_cache_count) == 0);
524 LASSERT(list_empty(&sai->sai_entries_agl));
525
526 iput(inode);
527 kfree(sai);
528 }
529 }
530
531 /* Do NOT forget to drop inode refcount when into sai_entries_agl. */
532 static void ll_agl_trigger(struct inode *inode, struct ll_statahead_info *sai)
533 {
534 struct ll_inode_info *lli = ll_i2info(inode);
535 __u64 index = lli->lli_agl_index;
536 int rc;
537
538 LASSERT(list_empty(&lli->lli_agl_list));
539
540 /* AGL maybe fall behind statahead with one entry */
541 if (is_omitted_entry(sai, index + 1)) {
542 lli->lli_agl_index = 0;
543 iput(inode);
544 return;
545 }
546
547 /* Someone is in glimpse (sync or async), do nothing. */
548 rc = down_write_trylock(&lli->lli_glimpse_sem);
549 if (rc == 0) {
550 lli->lli_agl_index = 0;
551 iput(inode);
552 return;
553 }
554
555 /*
556 * Someone triggered glimpse within 1 sec before.
557 * 1) The former glimpse succeeded with glimpse lock granted by OST, and
558 * if the lock is still cached on client, AGL needs to do nothing. If
559 * it is cancelled by other client, AGL maybe cannot obtain new lock
560 * for no glimpse callback triggered by AGL.
561 * 2) The former glimpse succeeded, but OST did not grant glimpse lock.
562 * Under such case, it is quite possible that the OST will not grant
563 * glimpse lock for AGL also.
564 * 3) The former glimpse failed, compared with other two cases, it is
565 * relative rare. AGL can ignore such case, and it will not muchly
566 * affect the performance.
567 */
568 if (lli->lli_glimpse_time != 0 &&
569 time_before(cfs_time_shift(-1), lli->lli_glimpse_time)) {
570 up_write(&lli->lli_glimpse_sem);
571 lli->lli_agl_index = 0;
572 iput(inode);
573 return;
574 }
575
576 CDEBUG(D_READA, "Handling (init) async glimpse: inode = "
577 DFID", idx = %llu\n", PFID(&lli->lli_fid), index);
578
579 cl_agl(inode);
580 lli->lli_agl_index = 0;
581 lli->lli_glimpse_time = cfs_time_current();
582 up_write(&lli->lli_glimpse_sem);
583
584 CDEBUG(D_READA, "Handled (init) async glimpse: inode= "
585 DFID", idx = %llu, rc = %d\n",
586 PFID(&lli->lli_fid), index, rc);
587
588 iput(inode);
589 }
590
591 static void ll_post_statahead(struct ll_statahead_info *sai)
592 {
593 struct inode *dir = sai->sai_inode;
594 struct inode *child;
595 struct ll_inode_info *lli = ll_i2info(dir);
596 struct ll_sa_entry *entry;
597 struct md_enqueue_info *minfo;
598 struct lookup_intent *it;
599 struct ptlrpc_request *req;
600 struct mdt_body *body;
601 int rc = 0;
602
603 spin_lock(&lli->lli_sa_lock);
604 if (unlikely(list_empty(&sai->sai_entries_received))) {
605 spin_unlock(&lli->lli_sa_lock);
606 return;
607 }
608 entry = list_entry(sai->sai_entries_received.next,
609 struct ll_sa_entry, se_list);
610 atomic_inc(&entry->se_refcount);
611 list_del_init(&entry->se_list);
612 spin_unlock(&lli->lli_sa_lock);
613
614 LASSERT(entry->se_handle != 0);
615
616 minfo = entry->se_minfo;
617 it = &minfo->mi_it;
618 req = entry->se_req;
619 body = req_capsule_server_get(&req->rq_pill, &RMF_MDT_BODY);
620 if (!body) {
621 rc = -EFAULT;
622 goto out;
623 }
624
625 child = entry->se_inode;
626 if (!child) {
627 /*
628 * lookup.
629 */
630 LASSERT(fid_is_zero(&minfo->mi_data.op_fid2));
631
632 /* XXX: No fid in reply, this is probably cross-ref case.
633 * SA can't handle it yet.
634 */
635 if (body->valid & OBD_MD_MDS) {
636 rc = -EAGAIN;
637 goto out;
638 }
639 } else {
640 /*
641 * revalidate.
642 */
643 /* unlinked and re-created with the same name */
644 if (unlikely(!lu_fid_eq(&minfo->mi_data.op_fid2, &body->fid1))) {
645 entry->se_inode = NULL;
646 iput(child);
647 child = NULL;
648 }
649 }
650
651 it->it_lock_handle = entry->se_handle;
652 rc = md_revalidate_lock(ll_i2mdexp(dir), it, ll_inode2fid(dir), NULL);
653 if (rc != 1) {
654 rc = -EAGAIN;
655 goto out;
656 }
657
658 rc = ll_prep_inode(&child, req, dir->i_sb, it);
659 if (rc)
660 goto out;
661
662 CDEBUG(D_DLMTRACE, "%s: setting l_data to inode "DFID"%p\n",
663 ll_get_fsname(child->i_sb, NULL, 0),
664 PFID(ll_inode2fid(child)), child);
665 ll_set_lock_data(ll_i2sbi(dir)->ll_md_exp, child, it, NULL);
666
667 entry->se_inode = child;
668
669 if (agl_should_run(sai, child))
670 ll_agl_add(sai, child, entry->se_index);
671
672 out:
673 /* The "ll_sa_entry_to_stated()" will drop related ldlm ibits lock
674 * reference count by calling "ll_intent_drop_lock()" in spite of the
675 * above operations failed or not. Do not worry about calling
676 * "ll_intent_drop_lock()" more than once.
677 */
678 rc = ll_sa_entry_to_stated(sai, entry,
679 rc < 0 ? SA_ENTRY_INVA : SA_ENTRY_SUCC);
680 if (rc == 0 && entry->se_index == sai->sai_index_wait)
681 wake_up(&sai->sai_waitq);
682 ll_sa_entry_put(sai, entry);
683 }
684
685 static int ll_statahead_interpret(struct ptlrpc_request *req,
686 struct md_enqueue_info *minfo, int rc)
687 {
688 struct lookup_intent *it = &minfo->mi_it;
689 struct inode *dir = minfo->mi_dir;
690 struct ll_inode_info *lli = ll_i2info(dir);
691 struct ll_statahead_info *sai = NULL;
692 struct ll_sa_entry *entry;
693 __u64 handle = 0;
694 int wakeup;
695
696 if (it_disposition(it, DISP_LOOKUP_NEG))
697 rc = -ENOENT;
698
699 if (rc == 0) {
700 /* release ibits lock ASAP to avoid deadlock when statahead
701 * thread enqueues lock on parent in readdir and another
702 * process enqueues lock on child with parent lock held, eg.
703 * unlink.
704 */
705 handle = it->it_lock_handle;
706 ll_intent_drop_lock(it);
707 }
708
709 spin_lock(&lli->lli_sa_lock);
710 /* stale entry */
711 if (unlikely(!lli->lli_sai ||
712 lli->lli_sai->sai_generation != minfo->mi_generation)) {
713 spin_unlock(&lli->lli_sa_lock);
714 rc = -ESTALE;
715 goto out;
716 } else {
717 sai = ll_sai_get(lli->lli_sai);
718 if (unlikely(!thread_is_running(&sai->sai_thread))) {
719 sai->sai_replied++;
720 spin_unlock(&lli->lli_sa_lock);
721 rc = -EBADFD;
722 goto out;
723 }
724
725 entry = ll_sa_entry_get_byindex(sai, minfo->mi_cbdata);
726 if (!entry) {
727 sai->sai_replied++;
728 spin_unlock(&lli->lli_sa_lock);
729 rc = -EIDRM;
730 goto out;
731 }
732
733 if (rc != 0) {
734 do_sa_entry_to_stated(sai, entry, SA_ENTRY_INVA);
735 wakeup = (entry->se_index == sai->sai_index_wait);
736 } else {
737 entry->se_minfo = minfo;
738 entry->se_req = ptlrpc_request_addref(req);
739 /* Release the async ibits lock ASAP to avoid deadlock
740 * when statahead thread tries to enqueue lock on parent
741 * for readpage and other tries to enqueue lock on child
742 * with parent's lock held, for example: unlink.
743 */
744 entry->se_handle = handle;
745 wakeup = list_empty(&sai->sai_entries_received);
746 list_add_tail(&entry->se_list,
747 &sai->sai_entries_received);
748 }
749 sai->sai_replied++;
750 spin_unlock(&lli->lli_sa_lock);
751
752 ll_sa_entry_put(sai, entry);
753 if (wakeup)
754 wake_up(&sai->sai_thread.t_ctl_waitq);
755 }
756
757 out:
758 if (rc != 0) {
759 ll_intent_release(it);
760 iput(dir);
761 kfree(minfo);
762 }
763 if (sai)
764 ll_sai_put(sai);
765 return rc;
766 }
767
768 static void sa_args_fini(struct md_enqueue_info *minfo,
769 struct ldlm_enqueue_info *einfo)
770 {
771 LASSERT(minfo && einfo);
772 iput(minfo->mi_dir);
773 kfree(minfo);
774 kfree(einfo);
775 }
776
777 /**
778 * prepare arguments for async stat RPC.
779 */
780 static int sa_args_init(struct inode *dir, struct inode *child,
781 struct ll_sa_entry *entry, struct md_enqueue_info **pmi,
782 struct ldlm_enqueue_info **pei)
783 {
784 struct qstr *qstr = &entry->se_qstr;
785 struct ll_inode_info *lli = ll_i2info(dir);
786 struct md_enqueue_info *minfo;
787 struct ldlm_enqueue_info *einfo;
788 struct md_op_data *op_data;
789
790 einfo = kzalloc(sizeof(*einfo), GFP_NOFS);
791 if (!einfo)
792 return -ENOMEM;
793
794 minfo = kzalloc(sizeof(*minfo), GFP_NOFS);
795 if (!minfo) {
796 kfree(einfo);
797 return -ENOMEM;
798 }
799
800 op_data = ll_prep_md_op_data(&minfo->mi_data, dir, child, qstr->name,
801 qstr->len, 0, LUSTRE_OPC_ANY, NULL);
802 if (IS_ERR(op_data)) {
803 kfree(einfo);
804 kfree(minfo);
805 return PTR_ERR(op_data);
806 }
807
808 minfo->mi_it.it_op = IT_GETATTR;
809 minfo->mi_dir = igrab(dir);
810 minfo->mi_cb = ll_statahead_interpret;
811 minfo->mi_generation = lli->lli_sai->sai_generation;
812 minfo->mi_cbdata = entry->se_index;
813
814 einfo->ei_type = LDLM_IBITS;
815 einfo->ei_mode = it_to_lock_mode(&minfo->mi_it);
816 einfo->ei_cb_bl = ll_md_blocking_ast;
817 einfo->ei_cb_cp = ldlm_completion_ast;
818 einfo->ei_cb_gl = NULL;
819 einfo->ei_cbdata = NULL;
820
821 *pmi = minfo;
822 *pei = einfo;
823
824 return 0;
825 }
826
827 static int do_sa_lookup(struct inode *dir, struct ll_sa_entry *entry)
828 {
829 struct md_enqueue_info *minfo;
830 struct ldlm_enqueue_info *einfo;
831 int rc;
832
833 rc = sa_args_init(dir, NULL, entry, &minfo, &einfo);
834 if (rc)
835 return rc;
836
837 rc = md_intent_getattr_async(ll_i2mdexp(dir), minfo, einfo);
838 if (rc < 0)
839 sa_args_fini(minfo, einfo);
840
841 return rc;
842 }
843
844 /**
845 * similar to ll_revalidate_it().
846 * \retval 1 -- dentry valid
847 * \retval 0 -- will send stat-ahead request
848 * \retval others -- prepare stat-ahead request failed
849 */
850 static int do_sa_revalidate(struct inode *dir, struct ll_sa_entry *entry,
851 struct dentry *dentry)
852 {
853 struct inode *inode = d_inode(dentry);
854 struct lookup_intent it = { .it_op = IT_GETATTR,
855 .it_lock_handle = 0 };
856 struct md_enqueue_info *minfo;
857 struct ldlm_enqueue_info *einfo;
858 int rc;
859
860 if (unlikely(!inode))
861 return 1;
862
863 if (d_mountpoint(dentry))
864 return 1;
865
866 entry->se_inode = igrab(inode);
867 rc = md_revalidate_lock(ll_i2mdexp(dir), &it, ll_inode2fid(inode),
868 NULL);
869 if (rc == 1) {
870 entry->se_handle = it.it_lock_handle;
871 ll_intent_release(&it);
872 return 1;
873 }
874
875 rc = sa_args_init(dir, inode, entry, &minfo, &einfo);
876 if (rc) {
877 entry->se_inode = NULL;
878 iput(inode);
879 return rc;
880 }
881
882 rc = md_intent_getattr_async(ll_i2mdexp(dir), minfo, einfo);
883 if (rc < 0) {
884 entry->se_inode = NULL;
885 iput(inode);
886 sa_args_fini(minfo, einfo);
887 }
888
889 return rc;
890 }
891
892 static void ll_statahead_one(struct dentry *parent, const char *entry_name,
893 int entry_name_len)
894 {
895 struct inode *dir = d_inode(parent);
896 struct ll_inode_info *lli = ll_i2info(dir);
897 struct ll_statahead_info *sai = lli->lli_sai;
898 struct dentry *dentry = NULL;
899 struct ll_sa_entry *entry;
900 int rc;
901 int rc1;
902
903 entry = ll_sa_entry_alloc(parent, sai, sai->sai_index, entry_name,
904 entry_name_len);
905 if (IS_ERR(entry))
906 return;
907
908 dentry = d_lookup(parent, &entry->se_qstr);
909 if (!dentry) {
910 rc = do_sa_lookup(dir, entry);
911 } else {
912 rc = do_sa_revalidate(dir, entry, dentry);
913 if (rc == 1 && agl_should_run(sai, d_inode(dentry)))
914 ll_agl_add(sai, d_inode(dentry), entry->se_index);
915
916 dput(dentry);
917 }
918
919 if (rc) {
920 rc1 = ll_sa_entry_to_stated(sai, entry,
921 rc < 0 ? SA_ENTRY_INVA : SA_ENTRY_SUCC);
922 if (rc1 == 0 && entry->se_index == sai->sai_index_wait)
923 wake_up(&sai->sai_waitq);
924 } else {
925 sai->sai_sent++;
926 }
927
928 sai->sai_index++;
929 /* drop one refcount on entry by ll_sa_entry_alloc */
930 ll_sa_entry_put(sai, entry);
931 }
932
933 static int ll_agl_thread(void *arg)
934 {
935 struct dentry *parent = arg;
936 struct inode *dir = d_inode(parent);
937 struct ll_inode_info *plli = ll_i2info(dir);
938 struct ll_inode_info *clli;
939 struct ll_sb_info *sbi = ll_i2sbi(dir);
940 struct ll_statahead_info *sai = ll_sai_get(plli->lli_sai);
941 struct ptlrpc_thread *thread = &sai->sai_agl_thread;
942 struct l_wait_info lwi = { 0 };
943
944 thread->t_pid = current_pid();
945 CDEBUG(D_READA, "agl thread started: sai %p, parent %pd\n",
946 sai, parent);
947
948 atomic_inc(&sbi->ll_agl_total);
949 spin_lock(&plli->lli_agl_lock);
950 sai->sai_agl_valid = 1;
951 if (thread_is_init(thread))
952 /* If someone else has changed the thread state
953 * (e.g. already changed to SVC_STOPPING), we can't just
954 * blindly overwrite that setting.
955 */
956 thread_set_flags(thread, SVC_RUNNING);
957 spin_unlock(&plli->lli_agl_lock);
958 wake_up(&thread->t_ctl_waitq);
959
960 while (1) {
961 l_wait_event(thread->t_ctl_waitq,
962 !list_empty(&sai->sai_entries_agl) ||
963 !thread_is_running(thread),
964 &lwi);
965
966 if (!thread_is_running(thread))
967 break;
968
969 spin_lock(&plli->lli_agl_lock);
970 /* The statahead thread maybe help to process AGL entries,
971 * so check whether list empty again.
972 */
973 if (!list_empty(&sai->sai_entries_agl)) {
974 clli = list_entry(sai->sai_entries_agl.next,
975 struct ll_inode_info, lli_agl_list);
976 list_del_init(&clli->lli_agl_list);
977 spin_unlock(&plli->lli_agl_lock);
978 ll_agl_trigger(&clli->lli_vfs_inode, sai);
979 } else {
980 spin_unlock(&plli->lli_agl_lock);
981 }
982 }
983
984 spin_lock(&plli->lli_agl_lock);
985 sai->sai_agl_valid = 0;
986 while (!list_empty(&sai->sai_entries_agl)) {
987 clli = list_entry(sai->sai_entries_agl.next,
988 struct ll_inode_info, lli_agl_list);
989 list_del_init(&clli->lli_agl_list);
990 spin_unlock(&plli->lli_agl_lock);
991 clli->lli_agl_index = 0;
992 iput(&clli->lli_vfs_inode);
993 spin_lock(&plli->lli_agl_lock);
994 }
995 thread_set_flags(thread, SVC_STOPPED);
996 spin_unlock(&plli->lli_agl_lock);
997 wake_up(&thread->t_ctl_waitq);
998 ll_sai_put(sai);
999 CDEBUG(D_READA, "agl thread stopped: sai %p, parent %pd\n",
1000 sai, parent);
1001 return 0;
1002 }
1003
1004 static void ll_start_agl(struct dentry *parent, struct ll_statahead_info *sai)
1005 {
1006 struct ptlrpc_thread *thread = &sai->sai_agl_thread;
1007 struct l_wait_info lwi = { 0 };
1008 struct ll_inode_info *plli;
1009 struct task_struct *task;
1010
1011 CDEBUG(D_READA, "start agl thread: sai %p, parent %pd\n",
1012 sai, parent);
1013
1014 plli = ll_i2info(d_inode(parent));
1015 task = kthread_run(ll_agl_thread, parent, "ll_agl_%u",
1016 plli->lli_opendir_pid);
1017 if (IS_ERR(task)) {
1018 CERROR("can't start ll_agl thread, rc: %ld\n", PTR_ERR(task));
1019 thread_set_flags(thread, SVC_STOPPED);
1020 return;
1021 }
1022
1023 l_wait_event(thread->t_ctl_waitq,
1024 thread_is_running(thread) || thread_is_stopped(thread),
1025 &lwi);
1026 }
1027
1028 static int ll_statahead_thread(void *arg)
1029 {
1030 struct dentry *parent = arg;
1031 struct inode *dir = d_inode(parent);
1032 struct ll_inode_info *plli = ll_i2info(dir);
1033 struct ll_inode_info *clli;
1034 struct ll_sb_info *sbi = ll_i2sbi(dir);
1035 struct ll_statahead_info *sai = ll_sai_get(plli->lli_sai);
1036 struct ptlrpc_thread *thread = &sai->sai_thread;
1037 struct ptlrpc_thread *agl_thread = &sai->sai_agl_thread;
1038 struct page *page;
1039 __u64 pos = 0;
1040 int first = 0;
1041 int rc = 0;
1042 struct ll_dir_chain chain;
1043 struct l_wait_info lwi = { 0 };
1044
1045 thread->t_pid = current_pid();
1046 CDEBUG(D_READA, "statahead thread starting: sai %p, parent %pd\n",
1047 sai, parent);
1048
1049 if (sbi->ll_flags & LL_SBI_AGL_ENABLED)
1050 ll_start_agl(parent, sai);
1051
1052 atomic_inc(&sbi->ll_sa_total);
1053 spin_lock(&plli->lli_sa_lock);
1054 if (thread_is_init(thread))
1055 /* If someone else has changed the thread state
1056 * (e.g. already changed to SVC_STOPPING), we can't just
1057 * blindly overwrite that setting.
1058 */
1059 thread_set_flags(thread, SVC_RUNNING);
1060 spin_unlock(&plli->lli_sa_lock);
1061 wake_up(&thread->t_ctl_waitq);
1062
1063 ll_dir_chain_init(&chain);
1064 page = ll_get_dir_page(dir, pos, &chain);
1065
1066 while (1) {
1067 struct lu_dirpage *dp;
1068 struct lu_dirent *ent;
1069
1070 if (IS_ERR(page)) {
1071 rc = PTR_ERR(page);
1072 CDEBUG(D_READA, "error reading dir "DFID" at %llu/%llu: [rc %d] [parent %u]\n",
1073 PFID(ll_inode2fid(dir)), pos, sai->sai_index,
1074 rc, plli->lli_opendir_pid);
1075 goto out;
1076 }
1077
1078 dp = page_address(page);
1079 for (ent = lu_dirent_start(dp); ent;
1080 ent = lu_dirent_next(ent)) {
1081 __u64 hash;
1082 int namelen;
1083 char *name;
1084
1085 hash = le64_to_cpu(ent->lde_hash);
1086 if (unlikely(hash < pos))
1087 /*
1088 * Skip until we find target hash value.
1089 */
1090 continue;
1091
1092 namelen = le16_to_cpu(ent->lde_namelen);
1093 if (unlikely(namelen == 0))
1094 /*
1095 * Skip dummy record.
1096 */
1097 continue;
1098
1099 name = ent->lde_name;
1100 if (name[0] == '.') {
1101 if (namelen == 1) {
1102 /*
1103 * skip "."
1104 */
1105 continue;
1106 } else if (name[1] == '.' && namelen == 2) {
1107 /*
1108 * skip ".."
1109 */
1110 continue;
1111 } else if (!sai->sai_ls_all) {
1112 /*
1113 * skip hidden files.
1114 */
1115 sai->sai_skip_hidden++;
1116 continue;
1117 }
1118 }
1119
1120 /*
1121 * don't stat-ahead first entry.
1122 */
1123 if (unlikely(++first == 1))
1124 continue;
1125
1126 keep_it:
1127 l_wait_event(thread->t_ctl_waitq,
1128 !sa_sent_full(sai) ||
1129 !list_empty(&sai->sai_entries_received) ||
1130 !list_empty(&sai->sai_entries_agl) ||
1131 !thread_is_running(thread),
1132 &lwi);
1133
1134 interpret_it:
1135 while (!list_empty(&sai->sai_entries_received))
1136 ll_post_statahead(sai);
1137
1138 if (unlikely(!thread_is_running(thread))) {
1139 ll_release_page(page, 0);
1140 rc = 0;
1141 goto out;
1142 }
1143
1144 /* If no window for metadata statahead, but there are
1145 * some AGL entries to be triggered, then try to help
1146 * to process the AGL entries.
1147 */
1148 if (sa_sent_full(sai)) {
1149 spin_lock(&plli->lli_agl_lock);
1150 while (!list_empty(&sai->sai_entries_agl)) {
1151 clli = list_entry(sai->sai_entries_agl.next,
1152 struct ll_inode_info, lli_agl_list);
1153 list_del_init(&clli->lli_agl_list);
1154 spin_unlock(&plli->lli_agl_lock);
1155 ll_agl_trigger(&clli->lli_vfs_inode,
1156 sai);
1157
1158 if (!list_empty(&sai->sai_entries_received))
1159 goto interpret_it;
1160
1161 if (unlikely(
1162 !thread_is_running(thread))) {
1163 ll_release_page(page, 0);
1164 rc = 0;
1165 goto out;
1166 }
1167
1168 if (!sa_sent_full(sai))
1169 goto do_it;
1170
1171 spin_lock(&plli->lli_agl_lock);
1172 }
1173 spin_unlock(&plli->lli_agl_lock);
1174
1175 goto keep_it;
1176 }
1177
1178 do_it:
1179 ll_statahead_one(parent, name, namelen);
1180 }
1181 pos = le64_to_cpu(dp->ldp_hash_end);
1182 if (pos == MDS_DIR_END_OFF) {
1183 /*
1184 * End of directory reached.
1185 */
1186 ll_release_page(page, 0);
1187 while (1) {
1188 l_wait_event(thread->t_ctl_waitq,
1189 !list_empty(&sai->sai_entries_received) ||
1190 sai->sai_sent == sai->sai_replied ||
1191 !thread_is_running(thread),
1192 &lwi);
1193
1194 while (!list_empty(&sai->sai_entries_received))
1195 ll_post_statahead(sai);
1196
1197 if (unlikely(!thread_is_running(thread))) {
1198 rc = 0;
1199 goto out;
1200 }
1201
1202 if (sai->sai_sent == sai->sai_replied &&
1203 list_empty(&sai->sai_entries_received))
1204 break;
1205 }
1206
1207 spin_lock(&plli->lli_agl_lock);
1208 while (!list_empty(&sai->sai_entries_agl) &&
1209 thread_is_running(thread)) {
1210 clli = list_entry(sai->sai_entries_agl.next,
1211 struct ll_inode_info, lli_agl_list);
1212 list_del_init(&clli->lli_agl_list);
1213 spin_unlock(&plli->lli_agl_lock);
1214 ll_agl_trigger(&clli->lli_vfs_inode, sai);
1215 spin_lock(&plli->lli_agl_lock);
1216 }
1217 spin_unlock(&plli->lli_agl_lock);
1218
1219 rc = 0;
1220 goto out;
1221 } else if (1) {
1222 /*
1223 * chain is exhausted.
1224 * Normal case: continue to the next page.
1225 */
1226 ll_release_page(page, le32_to_cpu(dp->ldp_flags) &
1227 LDF_COLLIDE);
1228 page = ll_get_dir_page(dir, pos, &chain);
1229 } else {
1230 LASSERT(le32_to_cpu(dp->ldp_flags) & LDF_COLLIDE);
1231 ll_release_page(page, 1);
1232 /*
1233 * go into overflow page.
1234 */
1235 }
1236 }
1237
1238 out:
1239 if (sai->sai_agl_valid) {
1240 spin_lock(&plli->lli_agl_lock);
1241 thread_set_flags(agl_thread, SVC_STOPPING);
1242 spin_unlock(&plli->lli_agl_lock);
1243 wake_up(&agl_thread->t_ctl_waitq);
1244
1245 CDEBUG(D_READA, "stop agl thread: sai %p pid %u\n",
1246 sai, (unsigned int)agl_thread->t_pid);
1247 l_wait_event(agl_thread->t_ctl_waitq,
1248 thread_is_stopped(agl_thread),
1249 &lwi);
1250 } else {
1251 /* Set agl_thread flags anyway. */
1252 thread_set_flags(&sai->sai_agl_thread, SVC_STOPPED);
1253 }
1254 ll_dir_chain_fini(&chain);
1255 spin_lock(&plli->lli_sa_lock);
1256 if (!list_empty(&sai->sai_entries_received)) {
1257 thread_set_flags(thread, SVC_STOPPING);
1258 spin_unlock(&plli->lli_sa_lock);
1259
1260 /* To release the resources held by received entries. */
1261 while (!list_empty(&sai->sai_entries_received))
1262 ll_post_statahead(sai);
1263
1264 spin_lock(&plli->lli_sa_lock);
1265 }
1266 thread_set_flags(thread, SVC_STOPPED);
1267 spin_unlock(&plli->lli_sa_lock);
1268 wake_up(&sai->sai_waitq);
1269 wake_up(&thread->t_ctl_waitq);
1270 ll_sai_put(sai);
1271 dput(parent);
1272 CDEBUG(D_READA, "statahead thread stopped: sai %p, parent %pd\n",
1273 sai, parent);
1274 return rc;
1275 }
1276
1277 /**
1278 * called in ll_file_release().
1279 */
1280 void ll_stop_statahead(struct inode *dir, void *key)
1281 {
1282 struct ll_inode_info *lli = ll_i2info(dir);
1283
1284 if (unlikely(!key))
1285 return;
1286
1287 spin_lock(&lli->lli_sa_lock);
1288 if (lli->lli_opendir_key != key || lli->lli_opendir_pid == 0) {
1289 spin_unlock(&lli->lli_sa_lock);
1290 return;
1291 }
1292
1293 lli->lli_opendir_key = NULL;
1294
1295 if (lli->lli_sai) {
1296 struct l_wait_info lwi = { 0 };
1297 struct ptlrpc_thread *thread = &lli->lli_sai->sai_thread;
1298
1299 if (!thread_is_stopped(thread)) {
1300 thread_set_flags(thread, SVC_STOPPING);
1301 spin_unlock(&lli->lli_sa_lock);
1302 wake_up(&thread->t_ctl_waitq);
1303
1304 CDEBUG(D_READA, "stop statahead thread: sai %p pid %u\n",
1305 lli->lli_sai, (unsigned int)thread->t_pid);
1306 l_wait_event(thread->t_ctl_waitq,
1307 thread_is_stopped(thread),
1308 &lwi);
1309 } else {
1310 spin_unlock(&lli->lli_sa_lock);
1311 }
1312
1313 /*
1314 * Put the ref which was held when first statahead_enter.
1315 * It maybe not the last ref for some statahead requests
1316 * maybe inflight.
1317 */
1318 ll_sai_put(lli->lli_sai);
1319 } else {
1320 lli->lli_opendir_pid = 0;
1321 spin_unlock(&lli->lli_sa_lock);
1322 }
1323 }
1324
1325 enum {
1326 /**
1327 * not first dirent, or is "."
1328 */
1329 LS_NONE_FIRST_DE = 0,
1330 /**
1331 * the first non-hidden dirent
1332 */
1333 LS_FIRST_DE,
1334 /**
1335 * the first hidden dirent, that is "."
1336 */
1337 LS_FIRST_DOT_DE
1338 };
1339
1340 static int is_first_dirent(struct inode *dir, struct dentry *dentry)
1341 {
1342 struct ll_dir_chain chain;
1343 struct qstr *target = &dentry->d_name;
1344 struct page *page;
1345 __u64 pos = 0;
1346 int dot_de;
1347 int rc = LS_NONE_FIRST_DE;
1348
1349 ll_dir_chain_init(&chain);
1350 page = ll_get_dir_page(dir, pos, &chain);
1351
1352 while (1) {
1353 struct lu_dirpage *dp;
1354 struct lu_dirent *ent;
1355
1356 if (IS_ERR(page)) {
1357 struct ll_inode_info *lli = ll_i2info(dir);
1358
1359 rc = PTR_ERR(page);
1360 CERROR("error reading dir "DFID" at %llu: [rc %d] [parent %u]\n",
1361 PFID(ll_inode2fid(dir)), pos,
1362 rc, lli->lli_opendir_pid);
1363 break;
1364 }
1365
1366 dp = page_address(page);
1367 for (ent = lu_dirent_start(dp); ent;
1368 ent = lu_dirent_next(ent)) {
1369 __u64 hash;
1370 int namelen;
1371 char *name;
1372
1373 hash = le64_to_cpu(ent->lde_hash);
1374 /* The ll_get_dir_page() can return any page containing
1375 * the given hash which may be not the start hash.
1376 */
1377 if (unlikely(hash < pos))
1378 continue;
1379
1380 namelen = le16_to_cpu(ent->lde_namelen);
1381 if (unlikely(namelen == 0))
1382 /*
1383 * skip dummy record.
1384 */
1385 continue;
1386
1387 name = ent->lde_name;
1388 if (name[0] == '.') {
1389 if (namelen == 1)
1390 /*
1391 * skip "."
1392 */
1393 continue;
1394 else if (name[1] == '.' && namelen == 2)
1395 /*
1396 * skip ".."
1397 */
1398 continue;
1399 else
1400 dot_de = 1;
1401 } else {
1402 dot_de = 0;
1403 }
1404
1405 if (dot_de && target->name[0] != '.') {
1406 CDEBUG(D_READA, "%.*s skip hidden file %.*s\n",
1407 target->len, target->name,
1408 namelen, name);
1409 continue;
1410 }
1411
1412 if (target->len != namelen ||
1413 memcmp(target->name, name, namelen) != 0)
1414 rc = LS_NONE_FIRST_DE;
1415 else if (!dot_de)
1416 rc = LS_FIRST_DE;
1417 else
1418 rc = LS_FIRST_DOT_DE;
1419
1420 ll_release_page(page, 0);
1421 goto out;
1422 }
1423 pos = le64_to_cpu(dp->ldp_hash_end);
1424 if (pos == MDS_DIR_END_OFF) {
1425 /*
1426 * End of directory reached.
1427 */
1428 ll_release_page(page, 0);
1429 break;
1430 } else if (1) {
1431 /*
1432 * chain is exhausted
1433 * Normal case: continue to the next page.
1434 */
1435 ll_release_page(page, le32_to_cpu(dp->ldp_flags) &
1436 LDF_COLLIDE);
1437 page = ll_get_dir_page(dir, pos, &chain);
1438 } else {
1439 /*
1440 * go into overflow page.
1441 */
1442 LASSERT(le32_to_cpu(dp->ldp_flags) & LDF_COLLIDE);
1443 ll_release_page(page, 1);
1444 }
1445 }
1446
1447 out:
1448 ll_dir_chain_fini(&chain);
1449 return rc;
1450 }
1451
1452 static void
1453 ll_sai_unplug(struct ll_statahead_info *sai, struct ll_sa_entry *entry)
1454 {
1455 struct ptlrpc_thread *thread = &sai->sai_thread;
1456 struct ll_sb_info *sbi = ll_i2sbi(sai->sai_inode);
1457 int hit;
1458
1459 if (entry && entry->se_stat == SA_ENTRY_SUCC)
1460 hit = 1;
1461 else
1462 hit = 0;
1463
1464 ll_sa_entry_fini(sai, entry);
1465 if (hit) {
1466 sai->sai_hit++;
1467 sai->sai_consecutive_miss = 0;
1468 sai->sai_max = min(2 * sai->sai_max, sbi->ll_sa_max);
1469 } else {
1470 struct ll_inode_info *lli = ll_i2info(sai->sai_inode);
1471
1472 sai->sai_miss++;
1473 sai->sai_consecutive_miss++;
1474 if (sa_low_hit(sai) && thread_is_running(thread)) {
1475 atomic_inc(&sbi->ll_sa_wrong);
1476 CDEBUG(D_READA, "Statahead for dir " DFID " hit ratio too low: hit/miss %llu/%llu, sent/replied %llu/%llu, stopping statahead thread\n",
1477 PFID(&lli->lli_fid), sai->sai_hit,
1478 sai->sai_miss, sai->sai_sent,
1479 sai->sai_replied);
1480 spin_lock(&lli->lli_sa_lock);
1481 if (!thread_is_stopped(thread))
1482 thread_set_flags(thread, SVC_STOPPING);
1483 spin_unlock(&lli->lli_sa_lock);
1484 }
1485 }
1486
1487 if (!thread_is_stopped(thread))
1488 wake_up(&thread->t_ctl_waitq);
1489 }
1490
1491 /**
1492 * Start statahead thread if this is the first dir entry.
1493 * Otherwise if a thread is started already, wait it until it is ahead of me.
1494 * \retval 1 -- find entry with lock in cache, the caller needs to do
1495 * nothing.
1496 * \retval 0 -- find entry in cache, but without lock, the caller needs
1497 * refresh from MDS.
1498 * \retval others -- the caller need to process as non-statahead.
1499 */
1500 int do_statahead_enter(struct inode *dir, struct dentry **dentryp,
1501 int only_unplug)
1502 {
1503 struct ll_inode_info *lli = ll_i2info(dir);
1504 struct ll_statahead_info *sai = lli->lli_sai;
1505 struct dentry *parent;
1506 struct ll_sa_entry *entry;
1507 struct ptlrpc_thread *thread;
1508 struct l_wait_info lwi = { 0 };
1509 struct task_struct *task;
1510 int rc = 0;
1511 struct ll_inode_info *plli;
1512
1513 LASSERT(lli->lli_opendir_pid == current_pid());
1514
1515 if (sai) {
1516 thread = &sai->sai_thread;
1517 if (unlikely(thread_is_stopped(thread) &&
1518 list_empty(&sai->sai_entries_stated))) {
1519 /* to release resource */
1520 ll_stop_statahead(dir, lli->lli_opendir_key);
1521 return -EAGAIN;
1522 }
1523
1524 if ((*dentryp)->d_name.name[0] == '.') {
1525 if (sai->sai_ls_all ||
1526 sai->sai_miss_hidden >= sai->sai_skip_hidden) {
1527 /*
1528 * Hidden dentry is the first one, or statahead
1529 * thread does not skip so many hidden dentries
1530 * before "sai_ls_all" enabled as below.
1531 */
1532 } else {
1533 if (!sai->sai_ls_all)
1534 /*
1535 * It maybe because hidden dentry is not
1536 * the first one, "sai_ls_all" was not
1537 * set, then "ls -al" missed. Enable
1538 * "sai_ls_all" for such case.
1539 */
1540 sai->sai_ls_all = 1;
1541
1542 /*
1543 * Such "getattr" has been skipped before
1544 * "sai_ls_all" enabled as above.
1545 */
1546 sai->sai_miss_hidden++;
1547 return -EAGAIN;
1548 }
1549 }
1550
1551 entry = ll_sa_entry_get_byname(sai, &(*dentryp)->d_name);
1552 if (!entry || only_unplug) {
1553 ll_sai_unplug(sai, entry);
1554 return entry ? 1 : -EAGAIN;
1555 }
1556
1557 if (!ll_sa_entry_stated(entry)) {
1558 sai->sai_index_wait = entry->se_index;
1559 lwi = LWI_TIMEOUT_INTR(cfs_time_seconds(30), NULL,
1560 LWI_ON_SIGNAL_NOOP, NULL);
1561 rc = l_wait_event(sai->sai_waitq,
1562 ll_sa_entry_stated(entry) ||
1563 thread_is_stopped(thread),
1564 &lwi);
1565 if (rc < 0) {
1566 ll_sai_unplug(sai, entry);
1567 return -EAGAIN;
1568 }
1569 }
1570
1571 if (entry->se_stat == SA_ENTRY_SUCC && entry->se_inode) {
1572 struct inode *inode = entry->se_inode;
1573 struct lookup_intent it = { .it_op = IT_GETATTR,
1574 .it_lock_handle =
1575 entry->se_handle };
1576 __u64 bits;
1577
1578 rc = md_revalidate_lock(ll_i2mdexp(dir), &it,
1579 ll_inode2fid(inode), &bits);
1580 if (rc == 1) {
1581 if (!d_inode(*dentryp)) {
1582 struct dentry *alias;
1583
1584 alias = ll_splice_alias(inode,
1585 *dentryp);
1586 if (IS_ERR(alias)) {
1587 ll_sai_unplug(sai, entry);
1588 return PTR_ERR(alias);
1589 }
1590 *dentryp = alias;
1591 } else if (d_inode(*dentryp) != inode) {
1592 /* revalidate, but inode is recreated */
1593 CDEBUG(D_READA, "%s: stale dentry %pd inode "DFID", statahead inode "DFID"\n",
1594 ll_get_fsname(d_inode(*dentryp)->i_sb, NULL, 0),
1595 *dentryp,
1596 PFID(ll_inode2fid(d_inode(*dentryp))),
1597 PFID(ll_inode2fid(inode)));
1598 ll_sai_unplug(sai, entry);
1599 return -ESTALE;
1600 } else {
1601 iput(inode);
1602 }
1603 entry->se_inode = NULL;
1604
1605 if ((bits & MDS_INODELOCK_LOOKUP) &&
1606 d_lustre_invalid(*dentryp))
1607 d_lustre_revalidate(*dentryp);
1608 ll_intent_release(&it);
1609 }
1610 }
1611
1612 ll_sai_unplug(sai, entry);
1613 return rc;
1614 }
1615
1616 /* I am the "lli_opendir_pid" owner, only me can set "lli_sai". */
1617 rc = is_first_dirent(dir, *dentryp);
1618 if (rc == LS_NONE_FIRST_DE) {
1619 /* It is not "ls -{a}l" operation, no need statahead for it. */
1620 rc = -EAGAIN;
1621 goto out;
1622 }
1623
1624 sai = ll_sai_alloc();
1625 if (!sai) {
1626 rc = -ENOMEM;
1627 goto out;
1628 }
1629
1630 sai->sai_ls_all = (rc == LS_FIRST_DOT_DE);
1631 sai->sai_inode = igrab(dir);
1632 if (unlikely(!sai->sai_inode)) {
1633 CWARN("Do not start stat ahead on dying inode "DFID"\n",
1634 PFID(&lli->lli_fid));
1635 rc = -ESTALE;
1636 goto out;
1637 }
1638
1639 /* get parent reference count here, and put it in ll_statahead_thread */
1640 parent = dget((*dentryp)->d_parent);
1641 if (unlikely(sai->sai_inode != d_inode(parent))) {
1642 struct ll_inode_info *nlli = ll_i2info(d_inode(parent));
1643
1644 CWARN("Race condition, someone changed %pd just now: old parent "DFID", new parent "DFID"\n",
1645 *dentryp,
1646 PFID(&lli->lli_fid), PFID(&nlli->lli_fid));
1647 dput(parent);
1648 iput(sai->sai_inode);
1649 rc = -EAGAIN;
1650 goto out;
1651 }
1652
1653 CDEBUG(D_READA, "start statahead thread: sai %p, parent %pd\n",
1654 sai, parent);
1655
1656 /* The sai buffer already has one reference taken at allocation time,
1657 * but as soon as we expose the sai by attaching it to the lli that
1658 * default reference can be dropped by another thread calling
1659 * ll_stop_statahead. We need to take a local reference to protect
1660 * the sai buffer while we intend to access it.
1661 */
1662 ll_sai_get(sai);
1663 lli->lli_sai = sai;
1664
1665 plli = ll_i2info(d_inode(parent));
1666 task = kthread_run(ll_statahead_thread, parent, "ll_sa_%u",
1667 plli->lli_opendir_pid);
1668 thread = &sai->sai_thread;
1669 if (IS_ERR(task)) {
1670 rc = PTR_ERR(task);
1671 CERROR("can't start ll_sa thread, rc: %d\n", rc);
1672 dput(parent);
1673 lli->lli_opendir_key = NULL;
1674 thread_set_flags(thread, SVC_STOPPED);
1675 thread_set_flags(&sai->sai_agl_thread, SVC_STOPPED);
1676 /* Drop both our own local reference and the default
1677 * reference from allocation time.
1678 */
1679 ll_sai_put(sai);
1680 ll_sai_put(sai);
1681 LASSERT(!lli->lli_sai);
1682 return -EAGAIN;
1683 }
1684
1685 l_wait_event(thread->t_ctl_waitq,
1686 thread_is_running(thread) || thread_is_stopped(thread),
1687 &lwi);
1688 ll_sai_put(sai);
1689
1690 /*
1691 * We don't stat-ahead for the first dirent since we are already in
1692 * lookup.
1693 */
1694 return -EAGAIN;
1695
1696 out:
1697 kfree(sai);
1698 spin_lock(&lli->lli_sa_lock);
1699 lli->lli_opendir_key = NULL;
1700 lli->lli_opendir_pid = 0;
1701 spin_unlock(&lli->lli_sa_lock);
1702 return rc;
1703 }
Linux kernel - Deliverables
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