1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright (C) 2018 HUAWEI, Inc.
4 * https://www.huawei.com/
5 */
6 #include "zdata.h"
7 #include "compress.h"
8 #include <linux/prefetch.h>
9
10 #include <trace/events/erofs.h>
11
12 /*
13 * since pclustersize is variable for big pcluster feature, introduce slab
14 * pools implementation for different pcluster sizes.
15 */
16 struct z_erofs_pcluster_slab {
17 struct kmem_cache *slab;
18 unsigned int maxpages;
19 char name[48];
20 };
21
22 #define _PCLP(n) { .maxpages = n }
23
24 static struct z_erofs_pcluster_slab pcluster_pool[] __read_mostly = {
25 _PCLP(1), _PCLP(4), _PCLP(16), _PCLP(64), _PCLP(128),
26 _PCLP(Z_EROFS_PCLUSTER_MAX_PAGES)
27 };
28
z_erofs_destroy_pcluster_pool(void)29 static void z_erofs_destroy_pcluster_pool(void)
30 {
31 int i;
32
33 for (i = 0; i < ARRAY_SIZE(pcluster_pool); ++i) {
34 if (!pcluster_pool[i].slab)
35 continue;
36 kmem_cache_destroy(pcluster_pool[i].slab);
37 pcluster_pool[i].slab = NULL;
38 }
39 }
40
z_erofs_create_pcluster_pool(void)41 static int z_erofs_create_pcluster_pool(void)
42 {
43 struct z_erofs_pcluster_slab *pcs;
44 struct z_erofs_pcluster *a;
45 unsigned int size;
46
47 for (pcs = pcluster_pool;
48 pcs < pcluster_pool + ARRAY_SIZE(pcluster_pool); ++pcs) {
49 size = struct_size(a, compressed_pages, pcs->maxpages);
50
51 sprintf(pcs->name, "erofs_pcluster-%u", pcs->maxpages);
52 pcs->slab = kmem_cache_create(pcs->name, size, 0,
53 SLAB_RECLAIM_ACCOUNT, NULL);
54 if (pcs->slab)
55 continue;
56
57 z_erofs_destroy_pcluster_pool();
58 return -ENOMEM;
59 }
60 return 0;
61 }
62
z_erofs_alloc_pcluster(unsigned int nrpages)63 static struct z_erofs_pcluster *z_erofs_alloc_pcluster(unsigned int nrpages)
64 {
65 int i;
66
67 for (i = 0; i < ARRAY_SIZE(pcluster_pool); ++i) {
68 struct z_erofs_pcluster_slab *pcs = pcluster_pool + i;
69 struct z_erofs_pcluster *pcl;
70
71 if (nrpages > pcs->maxpages)
72 continue;
73
74 pcl = kmem_cache_zalloc(pcs->slab, GFP_NOFS);
75 if (!pcl)
76 return ERR_PTR(-ENOMEM);
77 pcl->pclusterpages = nrpages;
78 return pcl;
79 }
80 return ERR_PTR(-EINVAL);
81 }
82
z_erofs_free_pcluster(struct z_erofs_pcluster * pcl)83 static void z_erofs_free_pcluster(struct z_erofs_pcluster *pcl)
84 {
85 int i;
86
87 for (i = 0; i < ARRAY_SIZE(pcluster_pool); ++i) {
88 struct z_erofs_pcluster_slab *pcs = pcluster_pool + i;
89
90 if (pcl->pclusterpages > pcs->maxpages)
91 continue;
92
93 kmem_cache_free(pcs->slab, pcl);
94 return;
95 }
96 DBG_BUGON(1);
97 }
98
99 /* how to allocate cached pages for a pcluster */
100 enum z_erofs_cache_alloctype {
101 DONTALLOC, /* don't allocate any cached pages */
102 /*
103 * try to use cached I/O if page allocation succeeds or fallback
104 * to in-place I/O instead to avoid any direct reclaim.
105 */
106 TRYALLOC,
107 };
108
109 /*
110 * tagged pointer with 1-bit tag for all compressed pages
111 * tag 0 - the page is just found with an extra page reference
112 */
113 typedef tagptr1_t compressed_page_t;
114
115 #define tag_compressed_page_justfound(page) \
116 tagptr_fold(compressed_page_t, page, 1)
117
118 static struct workqueue_struct *z_erofs_workqueue __read_mostly;
119
z_erofs_exit_zip_subsystem(void)120 void z_erofs_exit_zip_subsystem(void)
121 {
122 destroy_workqueue(z_erofs_workqueue);
123 z_erofs_destroy_pcluster_pool();
124 }
125
z_erofs_init_workqueue(void)126 static inline int z_erofs_init_workqueue(void)
127 {
128 const unsigned int onlinecpus = num_possible_cpus();
129
130 /*
131 * no need to spawn too many threads, limiting threads could minimum
132 * scheduling overhead, perhaps per-CPU threads should be better?
133 */
134 z_erofs_workqueue = alloc_workqueue("erofs_unzipd",
135 WQ_UNBOUND | WQ_HIGHPRI,
136 onlinecpus + onlinecpus / 4);
137 return z_erofs_workqueue ? 0 : -ENOMEM;
138 }
139
z_erofs_init_zip_subsystem(void)140 int __init z_erofs_init_zip_subsystem(void)
141 {
142 int err = z_erofs_create_pcluster_pool();
143
144 if (err)
145 return err;
146 err = z_erofs_init_workqueue();
147 if (err)
148 z_erofs_destroy_pcluster_pool();
149 return err;
150 }
151
152 enum z_erofs_collectmode {
153 COLLECT_SECONDARY,
154 COLLECT_PRIMARY,
155 /*
156 * The current collection was the tail of an exist chain, in addition
157 * that the previous processed chained collections are all decided to
158 * be hooked up to it.
159 * A new chain will be created for the remaining collections which are
160 * not processed yet, therefore different from COLLECT_PRIMARY_FOLLOWED,
161 * the next collection cannot reuse the whole page safely in
162 * the following scenario:
163 * ________________________________________________________________
164 * | tail (partial) page | head (partial) page |
165 * | (belongs to the next cl) | (belongs to the current cl) |
166 * |_______PRIMARY_FOLLOWED_______|________PRIMARY_HOOKED___________|
167 */
168 COLLECT_PRIMARY_HOOKED,
169 /*
170 * a weak form of COLLECT_PRIMARY_FOLLOWED, the difference is that it
171 * could be dispatched into bypass queue later due to uptodated managed
172 * pages. All related online pages cannot be reused for inplace I/O (or
173 * pagevec) since it can be directly decoded without I/O submission.
174 */
175 COLLECT_PRIMARY_FOLLOWED_NOINPLACE,
176 /*
177 * The current collection has been linked with the owned chain, and
178 * could also be linked with the remaining collections, which means
179 * if the processing page is the tail page of the collection, thus
180 * the current collection can safely use the whole page (since
181 * the previous collection is under control) for in-place I/O, as
182 * illustrated below:
183 * ________________________________________________________________
184 * | tail (partial) page | head (partial) page |
185 * | (of the current cl) | (of the previous collection) |
186 * | PRIMARY_FOLLOWED or | |
187 * |_____PRIMARY_HOOKED___|____________PRIMARY_FOLLOWED____________|
188 *
189 * [ (*) the above page can be used as inplace I/O. ]
190 */
191 COLLECT_PRIMARY_FOLLOWED,
192 };
193
194 struct z_erofs_collector {
195 struct z_erofs_pagevec_ctor vector;
196
197 struct z_erofs_pcluster *pcl, *tailpcl;
198 struct z_erofs_collection *cl;
199 /* a pointer used to pick up inplace I/O pages */
200 struct page **icpage_ptr;
201 z_erofs_next_pcluster_t owned_head;
202
203 enum z_erofs_collectmode mode;
204 };
205
206 struct z_erofs_decompress_frontend {
207 struct inode *const inode;
208
209 struct z_erofs_collector clt;
210 struct erofs_map_blocks map;
211
212 bool readahead;
213 /* used for applying cache strategy on the fly */
214 bool backmost;
215 erofs_off_t headoffset;
216 };
217
218 #define COLLECTOR_INIT() { \
219 .owned_head = Z_EROFS_PCLUSTER_TAIL, \
220 .mode = COLLECT_PRIMARY_FOLLOWED }
221
222 #define DECOMPRESS_FRONTEND_INIT(__i) { \
223 .inode = __i, .clt = COLLECTOR_INIT(), \
224 .backmost = true, }
225
226 static struct page *z_pagemap_global[Z_EROFS_VMAP_GLOBAL_PAGES];
227 static DEFINE_MUTEX(z_pagemap_global_lock);
228
preload_compressed_pages(struct z_erofs_collector * clt,struct address_space * mc,enum z_erofs_cache_alloctype type,struct page ** pagepool)229 static void preload_compressed_pages(struct z_erofs_collector *clt,
230 struct address_space *mc,
231 enum z_erofs_cache_alloctype type,
232 struct page **pagepool)
233 {
234 struct z_erofs_pcluster *pcl = clt->pcl;
235 bool standalone = true;
236 gfp_t gfp = (mapping_gfp_mask(mc) & ~__GFP_DIRECT_RECLAIM) |
237 __GFP_NOMEMALLOC | __GFP_NORETRY | __GFP_NOWARN;
238 struct page **pages;
239 pgoff_t index;
240
241 if (clt->mode < COLLECT_PRIMARY_FOLLOWED)
242 return;
243
244 pages = pcl->compressed_pages;
245 index = pcl->obj.index;
246 for (; index < pcl->obj.index + pcl->pclusterpages; ++index, ++pages) {
247 struct page *page;
248 compressed_page_t t;
249 struct page *newpage = NULL;
250
251 /* the compressed page was loaded before */
252 if (READ_ONCE(*pages))
253 continue;
254
255 page = find_get_page(mc, index);
256
257 if (page) {
258 t = tag_compressed_page_justfound(page);
259 } else {
260 /* I/O is needed, no possible to decompress directly */
261 standalone = false;
262 switch (type) {
263 case TRYALLOC:
264 newpage = erofs_allocpage(pagepool, gfp);
265 if (!newpage)
266 continue;
267 set_page_private(newpage,
268 Z_EROFS_PREALLOCATED_PAGE);
269 t = tag_compressed_page_justfound(newpage);
270 break;
271 default: /* DONTALLOC */
272 continue;
273 }
274 }
275
276 if (!cmpxchg_relaxed(pages, NULL, tagptr_cast_ptr(t)))
277 continue;
278
279 if (page)
280 put_page(page);
281 else if (newpage)
282 erofs_pagepool_add(pagepool, newpage);
283 }
284
285 /*
286 * don't do inplace I/O if all compressed pages are available in
287 * managed cache since it can be moved to the bypass queue instead.
288 */
289 if (standalone)
290 clt->mode = COLLECT_PRIMARY_FOLLOWED_NOINPLACE;
291 }
292
293 /* called by erofs_shrinker to get rid of all compressed_pages */
erofs_try_to_free_all_cached_pages(struct erofs_sb_info * sbi,struct erofs_workgroup * grp)294 int erofs_try_to_free_all_cached_pages(struct erofs_sb_info *sbi,
295 struct erofs_workgroup *grp)
296 {
297 struct z_erofs_pcluster *const pcl =
298 container_of(grp, struct z_erofs_pcluster, obj);
299 int i;
300
301 /*
302 * refcount of workgroup is now freezed as 1,
303 * therefore no need to worry about available decompression users.
304 */
305 for (i = 0; i < pcl->pclusterpages; ++i) {
306 struct page *page = pcl->compressed_pages[i];
307
308 if (!page)
309 continue;
310
311 /* block other users from reclaiming or migrating the page */
312 if (!trylock_page(page))
313 return -EBUSY;
314
315 if (!erofs_page_is_managed(sbi, page))
316 continue;
317
318 /* barrier is implied in the following 'unlock_page' */
319 WRITE_ONCE(pcl->compressed_pages[i], NULL);
320 detach_page_private(page);
321 unlock_page(page);
322 }
323 return 0;
324 }
325
erofs_try_to_free_cached_page(struct page * page)326 int erofs_try_to_free_cached_page(struct page *page)
327 {
328 struct z_erofs_pcluster *const pcl = (void *)page_private(page);
329 int ret = 0; /* 0 - busy */
330
331 if (erofs_workgroup_try_to_freeze(&pcl->obj, 1)) {
332 unsigned int i;
333
334 for (i = 0; i < pcl->pclusterpages; ++i) {
335 if (pcl->compressed_pages[i] == page) {
336 WRITE_ONCE(pcl->compressed_pages[i], NULL);
337 ret = 1;
338 break;
339 }
340 }
341 erofs_workgroup_unfreeze(&pcl->obj, 1);
342
343 if (ret)
344 detach_page_private(page);
345 }
346 return ret;
347 }
348
349 /* page_type must be Z_EROFS_PAGE_TYPE_EXCLUSIVE */
z_erofs_try_inplace_io(struct z_erofs_collector * clt,struct page * page)350 static bool z_erofs_try_inplace_io(struct z_erofs_collector *clt,
351 struct page *page)
352 {
353 struct z_erofs_pcluster *const pcl = clt->pcl;
354
355 while (clt->icpage_ptr > pcl->compressed_pages)
356 if (!cmpxchg(--clt->icpage_ptr, NULL, page))
357 return true;
358 return false;
359 }
360
361 /* callers must be with collection lock held */
z_erofs_attach_page(struct z_erofs_collector * clt,struct page * page,enum z_erofs_page_type type,bool pvec_safereuse)362 static int z_erofs_attach_page(struct z_erofs_collector *clt,
363 struct page *page, enum z_erofs_page_type type,
364 bool pvec_safereuse)
365 {
366 int ret;
367
368 /* give priority for inplaceio */
369 if (clt->mode >= COLLECT_PRIMARY &&
370 type == Z_EROFS_PAGE_TYPE_EXCLUSIVE &&
371 z_erofs_try_inplace_io(clt, page))
372 return 0;
373
374 ret = z_erofs_pagevec_enqueue(&clt->vector, page, type,
375 pvec_safereuse);
376 clt->cl->vcnt += (unsigned int)ret;
377 return ret ? 0 : -EAGAIN;
378 }
379
z_erofs_try_to_claim_pcluster(struct z_erofs_collector * clt)380 static void z_erofs_try_to_claim_pcluster(struct z_erofs_collector *clt)
381 {
382 struct z_erofs_pcluster *pcl = clt->pcl;
383 z_erofs_next_pcluster_t *owned_head = &clt->owned_head;
384
385 /* type 1, nil pcluster (this pcluster doesn't belong to any chain.) */
386 if (cmpxchg(&pcl->next, Z_EROFS_PCLUSTER_NIL,
387 *owned_head) == Z_EROFS_PCLUSTER_NIL) {
388 *owned_head = &pcl->next;
389 /* so we can attach this pcluster to our submission chain. */
390 clt->mode = COLLECT_PRIMARY_FOLLOWED;
391 return;
392 }
393
394 /*
395 * type 2, link to the end of an existing open chain, be careful
396 * that its submission is controlled by the original attached chain.
397 */
398 if (cmpxchg(&pcl->next, Z_EROFS_PCLUSTER_TAIL,
399 *owned_head) == Z_EROFS_PCLUSTER_TAIL) {
400 *owned_head = Z_EROFS_PCLUSTER_TAIL;
401 clt->mode = COLLECT_PRIMARY_HOOKED;
402 clt->tailpcl = NULL;
403 return;
404 }
405 /* type 3, it belongs to a chain, but it isn't the end of the chain */
406 clt->mode = COLLECT_PRIMARY;
407 }
408
z_erofs_lookup_collection(struct z_erofs_collector * clt,struct inode * inode,struct erofs_map_blocks * map)409 static int z_erofs_lookup_collection(struct z_erofs_collector *clt,
410 struct inode *inode,
411 struct erofs_map_blocks *map)
412 {
413 struct z_erofs_pcluster *pcl = clt->pcl;
414 struct z_erofs_collection *cl;
415 unsigned int length;
416
417 /* to avoid unexpected loop formed by corrupted images */
418 if (clt->owned_head == &pcl->next || pcl == clt->tailpcl) {
419 DBG_BUGON(1);
420 return -EFSCORRUPTED;
421 }
422
423 cl = z_erofs_primarycollection(pcl);
424 if (cl->pageofs != (map->m_la & ~PAGE_MASK)) {
425 DBG_BUGON(1);
426 return -EFSCORRUPTED;
427 }
428
429 length = READ_ONCE(pcl->length);
430 if (length & Z_EROFS_PCLUSTER_FULL_LENGTH) {
431 if ((map->m_llen << Z_EROFS_PCLUSTER_LENGTH_BIT) > length) {
432 DBG_BUGON(1);
433 return -EFSCORRUPTED;
434 }
435 } else {
436 unsigned int llen = map->m_llen << Z_EROFS_PCLUSTER_LENGTH_BIT;
437
438 if (map->m_flags & EROFS_MAP_FULL_MAPPED)
439 llen |= Z_EROFS_PCLUSTER_FULL_LENGTH;
440
441 while (llen > length &&
442 length != cmpxchg_relaxed(&pcl->length, length, llen)) {
443 cpu_relax();
444 length = READ_ONCE(pcl->length);
445 }
446 }
447 mutex_lock(&cl->lock);
448 /* used to check tail merging loop due to corrupted images */
449 if (clt->owned_head == Z_EROFS_PCLUSTER_TAIL)
450 clt->tailpcl = pcl;
451
452 z_erofs_try_to_claim_pcluster(clt);
453 clt->cl = cl;
454 return 0;
455 }
456
z_erofs_register_collection(struct z_erofs_collector * clt,struct inode * inode,struct erofs_map_blocks * map)457 static int z_erofs_register_collection(struct z_erofs_collector *clt,
458 struct inode *inode,
459 struct erofs_map_blocks *map)
460 {
461 struct z_erofs_pcluster *pcl;
462 struct z_erofs_collection *cl;
463 struct erofs_workgroup *grp;
464 int err;
465
466 if (!(map->m_flags & EROFS_MAP_ENCODED)) {
467 DBG_BUGON(1);
468 return -EFSCORRUPTED;
469 }
470
471 /* no available pcluster, let's allocate one */
472 pcl = z_erofs_alloc_pcluster(map->m_plen >> PAGE_SHIFT);
473 if (IS_ERR(pcl))
474 return PTR_ERR(pcl);
475
476 atomic_set(&pcl->obj.refcount, 1);
477 pcl->obj.index = map->m_pa >> PAGE_SHIFT;
478 pcl->algorithmformat = map->m_algorithmformat;
479 pcl->length = (map->m_llen << Z_EROFS_PCLUSTER_LENGTH_BIT) |
480 (map->m_flags & EROFS_MAP_FULL_MAPPED ?
481 Z_EROFS_PCLUSTER_FULL_LENGTH : 0);
482
483 /* new pclusters should be claimed as type 1, primary and followed */
484 pcl->next = clt->owned_head;
485 clt->mode = COLLECT_PRIMARY_FOLLOWED;
486
487 cl = z_erofs_primarycollection(pcl);
488 cl->pageofs = map->m_la & ~PAGE_MASK;
489
490 /*
491 * lock all primary followed works before visible to others
492 * and mutex_trylock *never* fails for a new pcluster.
493 */
494 mutex_init(&cl->lock);
495 DBG_BUGON(!mutex_trylock(&cl->lock));
496
497 grp = erofs_insert_workgroup(inode->i_sb, &pcl->obj);
498 if (IS_ERR(grp)) {
499 err = PTR_ERR(grp);
500 goto err_out;
501 }
502
503 if (grp != &pcl->obj) {
504 clt->pcl = container_of(grp, struct z_erofs_pcluster, obj);
505 err = -EEXIST;
506 goto err_out;
507 }
508 /* used to check tail merging loop due to corrupted images */
509 if (clt->owned_head == Z_EROFS_PCLUSTER_TAIL)
510 clt->tailpcl = pcl;
511 clt->owned_head = &pcl->next;
512 clt->pcl = pcl;
513 clt->cl = cl;
514 return 0;
515
516 err_out:
517 mutex_unlock(&cl->lock);
518 z_erofs_free_pcluster(pcl);
519 return err;
520 }
521
z_erofs_collector_begin(struct z_erofs_collector * clt,struct inode * inode,struct erofs_map_blocks * map)522 static int z_erofs_collector_begin(struct z_erofs_collector *clt,
523 struct inode *inode,
524 struct erofs_map_blocks *map)
525 {
526 struct erofs_workgroup *grp;
527 int ret;
528
529 DBG_BUGON(clt->cl);
530
531 /* must be Z_EROFS_PCLUSTER_TAIL or pointed to previous collection */
532 DBG_BUGON(clt->owned_head == Z_EROFS_PCLUSTER_NIL);
533 DBG_BUGON(clt->owned_head == Z_EROFS_PCLUSTER_TAIL_CLOSED);
534
535 if (!PAGE_ALIGNED(map->m_pa)) {
536 DBG_BUGON(1);
537 return -EINVAL;
538 }
539
540 grp = erofs_find_workgroup(inode->i_sb, map->m_pa >> PAGE_SHIFT);
541 if (grp) {
542 clt->pcl = container_of(grp, struct z_erofs_pcluster, obj);
543 } else {
544 ret = z_erofs_register_collection(clt, inode, map);
545
546 if (!ret)
547 goto out;
548 if (ret != -EEXIST)
549 return ret;
550 }
551
552 ret = z_erofs_lookup_collection(clt, inode, map);
553 if (ret) {
554 erofs_workgroup_put(&clt->pcl->obj);
555 return ret;
556 }
557
558 out:
559 z_erofs_pagevec_ctor_init(&clt->vector, Z_EROFS_NR_INLINE_PAGEVECS,
560 clt->cl->pagevec, clt->cl->vcnt);
561
562 /* since file-backed online pages are traversed in reverse order */
563 clt->icpage_ptr = clt->pcl->compressed_pages + clt->pcl->pclusterpages;
564 return 0;
565 }
566
567 /*
568 * keep in mind that no referenced pclusters will be freed
569 * only after a RCU grace period.
570 */
z_erofs_rcu_callback(struct rcu_head * head)571 static void z_erofs_rcu_callback(struct rcu_head *head)
572 {
573 struct z_erofs_collection *const cl =
574 container_of(head, struct z_erofs_collection, rcu);
575
576 z_erofs_free_pcluster(container_of(cl, struct z_erofs_pcluster,
577 primary_collection));
578 }
579
erofs_workgroup_free_rcu(struct erofs_workgroup * grp)580 void erofs_workgroup_free_rcu(struct erofs_workgroup *grp)
581 {
582 struct z_erofs_pcluster *const pcl =
583 container_of(grp, struct z_erofs_pcluster, obj);
584 struct z_erofs_collection *const cl = z_erofs_primarycollection(pcl);
585
586 call_rcu(&cl->rcu, z_erofs_rcu_callback);
587 }
588
z_erofs_collection_put(struct z_erofs_collection * cl)589 static void z_erofs_collection_put(struct z_erofs_collection *cl)
590 {
591 struct z_erofs_pcluster *const pcl =
592 container_of(cl, struct z_erofs_pcluster, primary_collection);
593
594 erofs_workgroup_put(&pcl->obj);
595 }
596
z_erofs_collector_end(struct z_erofs_collector * clt)597 static bool z_erofs_collector_end(struct z_erofs_collector *clt)
598 {
599 struct z_erofs_collection *cl = clt->cl;
600
601 if (!cl)
602 return false;
603
604 z_erofs_pagevec_ctor_exit(&clt->vector, false);
605 mutex_unlock(&cl->lock);
606
607 /*
608 * if all pending pages are added, don't hold its reference
609 * any longer if the pcluster isn't hosted by ourselves.
610 */
611 if (clt->mode < COLLECT_PRIMARY_FOLLOWED_NOINPLACE)
612 z_erofs_collection_put(cl);
613
614 clt->cl = NULL;
615 return true;
616 }
617
should_alloc_managed_pages(struct z_erofs_decompress_frontend * fe,unsigned int cachestrategy,erofs_off_t la)618 static bool should_alloc_managed_pages(struct z_erofs_decompress_frontend *fe,
619 unsigned int cachestrategy,
620 erofs_off_t la)
621 {
622 if (cachestrategy <= EROFS_ZIP_CACHE_DISABLED)
623 return false;
624
625 if (fe->backmost)
626 return true;
627
628 return cachestrategy >= EROFS_ZIP_CACHE_READAROUND &&
629 la < fe->headoffset;
630 }
631
z_erofs_do_read_page(struct z_erofs_decompress_frontend * fe,struct page * page,struct page ** pagepool)632 static int z_erofs_do_read_page(struct z_erofs_decompress_frontend *fe,
633 struct page *page, struct page **pagepool)
634 {
635 struct inode *const inode = fe->inode;
636 struct erofs_sb_info *const sbi = EROFS_I_SB(inode);
637 struct erofs_map_blocks *const map = &fe->map;
638 struct z_erofs_collector *const clt = &fe->clt;
639 const loff_t offset = page_offset(page);
640 bool tight = true;
641
642 enum z_erofs_cache_alloctype cache_strategy;
643 enum z_erofs_page_type page_type;
644 unsigned int cur, end, spiltted, index;
645 int err = 0;
646
647 /* register locked file pages as online pages in pack */
648 z_erofs_onlinepage_init(page);
649
650 spiltted = 0;
651 end = PAGE_SIZE;
652 repeat:
653 cur = end - 1;
654
655 /* lucky, within the range of the current map_blocks */
656 if (offset + cur >= map->m_la &&
657 offset + cur < map->m_la + map->m_llen) {
658 /* didn't get a valid collection previously (very rare) */
659 if (!clt->cl)
660 goto restart_now;
661 goto hitted;
662 }
663
664 /* go ahead the next map_blocks */
665 erofs_dbg("%s: [out-of-range] pos %llu", __func__, offset + cur);
666
667 if (z_erofs_collector_end(clt))
668 fe->backmost = false;
669
670 map->m_la = offset + cur;
671 map->m_llen = 0;
672 err = z_erofs_map_blocks_iter(inode, map, 0);
673 if (err)
674 goto err_out;
675
676 restart_now:
677 if (!(map->m_flags & EROFS_MAP_MAPPED))
678 goto hitted;
679
680 err = z_erofs_collector_begin(clt, inode, map);
681 if (err)
682 goto err_out;
683
684 /* preload all compressed pages (maybe downgrade role if necessary) */
685 if (should_alloc_managed_pages(fe, sbi->opt.cache_strategy, map->m_la))
686 cache_strategy = TRYALLOC;
687 else
688 cache_strategy = DONTALLOC;
689
690 preload_compressed_pages(clt, MNGD_MAPPING(sbi),
691 cache_strategy, pagepool);
692
693 hitted:
694 /*
695 * Ensure the current partial page belongs to this submit chain rather
696 * than other concurrent submit chains or the noio(bypass) chain since
697 * those chains are handled asynchronously thus the page cannot be used
698 * for inplace I/O or pagevec (should be processed in strict order.)
699 */
700 tight &= (clt->mode >= COLLECT_PRIMARY_HOOKED &&
701 clt->mode != COLLECT_PRIMARY_FOLLOWED_NOINPLACE);
702
703 cur = end - min_t(unsigned int, offset + end - map->m_la, end);
704 if (!(map->m_flags & EROFS_MAP_MAPPED)) {
705 zero_user_segment(page, cur, end);
706 goto next_part;
707 }
708
709 /* let's derive page type */
710 page_type = cur ? Z_EROFS_VLE_PAGE_TYPE_HEAD :
711 (!spiltted ? Z_EROFS_PAGE_TYPE_EXCLUSIVE :
712 (tight ? Z_EROFS_PAGE_TYPE_EXCLUSIVE :
713 Z_EROFS_VLE_PAGE_TYPE_TAIL_SHARED));
714
715 if (cur)
716 tight &= (clt->mode >= COLLECT_PRIMARY_FOLLOWED);
717
718 retry:
719 err = z_erofs_attach_page(clt, page, page_type,
720 clt->mode >= COLLECT_PRIMARY_FOLLOWED);
721 /* should allocate an additional short-lived page for pagevec */
722 if (err == -EAGAIN) {
723 struct page *const newpage =
724 alloc_page(GFP_NOFS | __GFP_NOFAIL);
725
726 set_page_private(newpage, Z_EROFS_SHORTLIVED_PAGE);
727 err = z_erofs_attach_page(clt, newpage,
728 Z_EROFS_PAGE_TYPE_EXCLUSIVE, true);
729 if (!err)
730 goto retry;
731 }
732
733 if (err)
734 goto err_out;
735
736 index = page->index - (map->m_la >> PAGE_SHIFT);
737
738 z_erofs_onlinepage_fixup(page, index, true);
739
740 /* bump up the number of spiltted parts of a page */
741 ++spiltted;
742 /* also update nr_pages */
743 clt->cl->nr_pages = max_t(pgoff_t, clt->cl->nr_pages, index + 1);
744 next_part:
745 /* can be used for verification */
746 map->m_llen = offset + cur - map->m_la;
747
748 end = cur;
749 if (end > 0)
750 goto repeat;
751
752 out:
753 z_erofs_onlinepage_endio(page);
754
755 erofs_dbg("%s, finish page: %pK spiltted: %u map->m_llen %llu",
756 __func__, page, spiltted, map->m_llen);
757 return err;
758
759 /* if some error occurred while processing this page */
760 err_out:
761 SetPageError(page);
762 goto out;
763 }
764
765 static void z_erofs_decompressqueue_work(struct work_struct *work);
z_erofs_decompress_kickoff(struct z_erofs_decompressqueue * io,bool sync,int bios)766 static void z_erofs_decompress_kickoff(struct z_erofs_decompressqueue *io,
767 bool sync, int bios)
768 {
769 struct erofs_sb_info *const sbi = EROFS_SB(io->sb);
770
771 /* wake up the caller thread for sync decompression */
772 if (sync) {
773 unsigned long flags;
774
775 spin_lock_irqsave(&io->u.wait.lock, flags);
776 if (!atomic_add_return(bios, &io->pending_bios))
777 wake_up_locked(&io->u.wait);
778 spin_unlock_irqrestore(&io->u.wait.lock, flags);
779 return;
780 }
781
782 if (atomic_add_return(bios, &io->pending_bios))
783 return;
784 /* Use workqueue and sync decompression for atomic contexts only */
785 if (in_atomic() || irqs_disabled()) {
786 queue_work(z_erofs_workqueue, &io->u.work);
787 sbi->opt.readahead_sync_decompress = true;
788 return;
789 }
790 z_erofs_decompressqueue_work(&io->u.work);
791 }
792
z_erofs_page_is_invalidated(struct page * page)793 static bool z_erofs_page_is_invalidated(struct page *page)
794 {
795 return !page->mapping && !z_erofs_is_shortlived_page(page);
796 }
797
z_erofs_decompressqueue_endio(struct bio * bio)798 static void z_erofs_decompressqueue_endio(struct bio *bio)
799 {
800 tagptr1_t t = tagptr_init(tagptr1_t, bio->bi_private);
801 struct z_erofs_decompressqueue *q = tagptr_unfold_ptr(t);
802 blk_status_t err = bio->bi_status;
803 struct bio_vec *bvec;
804 struct bvec_iter_all iter_all;
805
806 bio_for_each_segment_all(bvec, bio, iter_all) {
807 struct page *page = bvec->bv_page;
808
809 DBG_BUGON(PageUptodate(page));
810 DBG_BUGON(z_erofs_page_is_invalidated(page));
811
812 if (err)
813 SetPageError(page);
814
815 if (erofs_page_is_managed(EROFS_SB(q->sb), page)) {
816 if (!err)
817 SetPageUptodate(page);
818 unlock_page(page);
819 }
820 }
821 z_erofs_decompress_kickoff(q, tagptr_unfold_tags(t), -1);
822 bio_put(bio);
823 }
824
z_erofs_decompress_pcluster(struct super_block * sb,struct z_erofs_pcluster * pcl,struct page ** pagepool)825 static int z_erofs_decompress_pcluster(struct super_block *sb,
826 struct z_erofs_pcluster *pcl,
827 struct page **pagepool)
828 {
829 struct erofs_sb_info *const sbi = EROFS_SB(sb);
830 struct z_erofs_pagevec_ctor ctor;
831 unsigned int i, inputsize, outputsize, llen, nr_pages;
832 struct page *pages_onstack[Z_EROFS_VMAP_ONSTACK_PAGES];
833 struct page **pages, **compressed_pages, *page;
834
835 enum z_erofs_page_type page_type;
836 bool overlapped, partial;
837 struct z_erofs_collection *cl;
838 int err;
839
840 might_sleep();
841 cl = z_erofs_primarycollection(pcl);
842 DBG_BUGON(!READ_ONCE(cl->nr_pages));
843
844 mutex_lock(&cl->lock);
845 nr_pages = cl->nr_pages;
846
847 if (nr_pages <= Z_EROFS_VMAP_ONSTACK_PAGES) {
848 pages = pages_onstack;
849 } else if (nr_pages <= Z_EROFS_VMAP_GLOBAL_PAGES &&
850 mutex_trylock(&z_pagemap_global_lock)) {
851 pages = z_pagemap_global;
852 } else {
853 gfp_t gfp_flags = GFP_KERNEL;
854
855 if (nr_pages > Z_EROFS_VMAP_GLOBAL_PAGES)
856 gfp_flags |= __GFP_NOFAIL;
857
858 pages = kvmalloc_array(nr_pages, sizeof(struct page *),
859 gfp_flags);
860
861 /* fallback to global pagemap for the lowmem scenario */
862 if (!pages) {
863 mutex_lock(&z_pagemap_global_lock);
864 pages = z_pagemap_global;
865 }
866 }
867
868 for (i = 0; i < nr_pages; ++i)
869 pages[i] = NULL;
870
871 err = 0;
872 z_erofs_pagevec_ctor_init(&ctor, Z_EROFS_NR_INLINE_PAGEVECS,
873 cl->pagevec, 0);
874
875 for (i = 0; i < cl->vcnt; ++i) {
876 unsigned int pagenr;
877
878 page = z_erofs_pagevec_dequeue(&ctor, &page_type);
879
880 /* all pages in pagevec ought to be valid */
881 DBG_BUGON(!page);
882 DBG_BUGON(z_erofs_page_is_invalidated(page));
883
884 if (z_erofs_put_shortlivedpage(pagepool, page))
885 continue;
886
887 if (page_type == Z_EROFS_VLE_PAGE_TYPE_HEAD)
888 pagenr = 0;
889 else
890 pagenr = z_erofs_onlinepage_index(page);
891
892 DBG_BUGON(pagenr >= nr_pages);
893
894 /*
895 * currently EROFS doesn't support multiref(dedup),
896 * so here erroring out one multiref page.
897 */
898 if (pages[pagenr]) {
899 DBG_BUGON(1);
900 SetPageError(pages[pagenr]);
901 z_erofs_onlinepage_endio(pages[pagenr]);
902 err = -EFSCORRUPTED;
903 }
904 pages[pagenr] = page;
905 }
906 z_erofs_pagevec_ctor_exit(&ctor, true);
907
908 overlapped = false;
909 compressed_pages = pcl->compressed_pages;
910
911 for (i = 0; i < pcl->pclusterpages; ++i) {
912 unsigned int pagenr;
913
914 page = compressed_pages[i];
915
916 /* all compressed pages ought to be valid */
917 DBG_BUGON(!page);
918 DBG_BUGON(z_erofs_page_is_invalidated(page));
919
920 if (!z_erofs_is_shortlived_page(page)) {
921 if (erofs_page_is_managed(sbi, page)) {
922 if (!PageUptodate(page))
923 err = -EIO;
924 continue;
925 }
926
927 /*
928 * only if non-head page can be selected
929 * for inplace decompression
930 */
931 pagenr = z_erofs_onlinepage_index(page);
932
933 DBG_BUGON(pagenr >= nr_pages);
934 if (pages[pagenr]) {
935 DBG_BUGON(1);
936 SetPageError(pages[pagenr]);
937 z_erofs_onlinepage_endio(pages[pagenr]);
938 err = -EFSCORRUPTED;
939 }
940 pages[pagenr] = page;
941
942 overlapped = true;
943 }
944
945 /* PG_error needs checking for all non-managed pages */
946 if (PageError(page)) {
947 DBG_BUGON(PageUptodate(page));
948 err = -EIO;
949 }
950 }
951
952 if (err)
953 goto out;
954
955 llen = pcl->length >> Z_EROFS_PCLUSTER_LENGTH_BIT;
956 if (nr_pages << PAGE_SHIFT >= cl->pageofs + llen) {
957 outputsize = llen;
958 partial = !(pcl->length & Z_EROFS_PCLUSTER_FULL_LENGTH);
959 } else {
960 outputsize = (nr_pages << PAGE_SHIFT) - cl->pageofs;
961 partial = true;
962 }
963
964 inputsize = pcl->pclusterpages * PAGE_SIZE;
965 err = z_erofs_decompress(&(struct z_erofs_decompress_req) {
966 .sb = sb,
967 .in = compressed_pages,
968 .out = pages,
969 .pageofs_out = cl->pageofs,
970 .inputsize = inputsize,
971 .outputsize = outputsize,
972 .alg = pcl->algorithmformat,
973 .inplace_io = overlapped,
974 .partial_decoding = partial
975 }, pagepool);
976
977 out:
978 /* must handle all compressed pages before ending pages */
979 for (i = 0; i < pcl->pclusterpages; ++i) {
980 page = compressed_pages[i];
981
982 if (erofs_page_is_managed(sbi, page))
983 continue;
984
985 /* recycle all individual short-lived pages */
986 (void)z_erofs_put_shortlivedpage(pagepool, page);
987
988 WRITE_ONCE(compressed_pages[i], NULL);
989 }
990
991 for (i = 0; i < nr_pages; ++i) {
992 page = pages[i];
993 if (!page)
994 continue;
995
996 DBG_BUGON(z_erofs_page_is_invalidated(page));
997
998 /* recycle all individual short-lived pages */
999 if (z_erofs_put_shortlivedpage(pagepool, page))
1000 continue;
1001
1002 if (err < 0)
1003 SetPageError(page);
1004
1005 z_erofs_onlinepage_endio(page);
1006 }
1007
1008 if (pages == z_pagemap_global)
1009 mutex_unlock(&z_pagemap_global_lock);
1010 else if (pages != pages_onstack)
1011 kvfree(pages);
1012
1013 cl->nr_pages = 0;
1014 cl->vcnt = 0;
1015
1016 /* all cl locks MUST be taken before the following line */
1017 WRITE_ONCE(pcl->next, Z_EROFS_PCLUSTER_NIL);
1018
1019 /* all cl locks SHOULD be released right now */
1020 mutex_unlock(&cl->lock);
1021
1022 z_erofs_collection_put(cl);
1023 return err;
1024 }
1025
z_erofs_decompress_queue(const struct z_erofs_decompressqueue * io,struct page ** pagepool)1026 static void z_erofs_decompress_queue(const struct z_erofs_decompressqueue *io,
1027 struct page **pagepool)
1028 {
1029 z_erofs_next_pcluster_t owned = io->head;
1030
1031 while (owned != Z_EROFS_PCLUSTER_TAIL_CLOSED) {
1032 struct z_erofs_pcluster *pcl;
1033
1034 /* no possible that 'owned' equals Z_EROFS_WORK_TPTR_TAIL */
1035 DBG_BUGON(owned == Z_EROFS_PCLUSTER_TAIL);
1036
1037 /* no possible that 'owned' equals NULL */
1038 DBG_BUGON(owned == Z_EROFS_PCLUSTER_NIL);
1039
1040 pcl = container_of(owned, struct z_erofs_pcluster, next);
1041 owned = READ_ONCE(pcl->next);
1042
1043 z_erofs_decompress_pcluster(io->sb, pcl, pagepool);
1044 }
1045 }
1046
z_erofs_decompressqueue_work(struct work_struct * work)1047 static void z_erofs_decompressqueue_work(struct work_struct *work)
1048 {
1049 struct z_erofs_decompressqueue *bgq =
1050 container_of(work, struct z_erofs_decompressqueue, u.work);
1051 struct page *pagepool = NULL;
1052
1053 DBG_BUGON(bgq->head == Z_EROFS_PCLUSTER_TAIL_CLOSED);
1054 z_erofs_decompress_queue(bgq, &pagepool);
1055
1056 erofs_release_pages(&pagepool);
1057 kvfree(bgq);
1058 }
1059
pickup_page_for_submission(struct z_erofs_pcluster * pcl,unsigned int nr,struct page ** pagepool,struct address_space * mc,gfp_t gfp)1060 static struct page *pickup_page_for_submission(struct z_erofs_pcluster *pcl,
1061 unsigned int nr,
1062 struct page **pagepool,
1063 struct address_space *mc,
1064 gfp_t gfp)
1065 {
1066 const pgoff_t index = pcl->obj.index;
1067 bool tocache = false;
1068
1069 struct address_space *mapping;
1070 struct page *oldpage, *page;
1071
1072 compressed_page_t t;
1073 int justfound;
1074
1075 repeat:
1076 page = READ_ONCE(pcl->compressed_pages[nr]);
1077 oldpage = page;
1078
1079 if (!page)
1080 goto out_allocpage;
1081
1082 /* process the target tagged pointer */
1083 t = tagptr_init(compressed_page_t, page);
1084 justfound = tagptr_unfold_tags(t);
1085 page = tagptr_unfold_ptr(t);
1086
1087 /*
1088 * preallocated cached pages, which is used to avoid direct reclaim
1089 * otherwise, it will go inplace I/O path instead.
1090 */
1091 if (page->private == Z_EROFS_PREALLOCATED_PAGE) {
1092 WRITE_ONCE(pcl->compressed_pages[nr], page);
1093 set_page_private(page, 0);
1094 tocache = true;
1095 goto out_tocache;
1096 }
1097 mapping = READ_ONCE(page->mapping);
1098
1099 /*
1100 * file-backed online pages in plcuster are all locked steady,
1101 * therefore it is impossible for `mapping' to be NULL.
1102 */
1103 if (mapping && mapping != mc)
1104 /* ought to be unmanaged pages */
1105 goto out;
1106
1107 /* directly return for shortlived page as well */
1108 if (z_erofs_is_shortlived_page(page))
1109 goto out;
1110
1111 lock_page(page);
1112
1113 /* only true if page reclaim goes wrong, should never happen */
1114 DBG_BUGON(justfound && PagePrivate(page));
1115
1116 /* the page is still in manage cache */
1117 if (page->mapping == mc) {
1118 WRITE_ONCE(pcl->compressed_pages[nr], page);
1119
1120 ClearPageError(page);
1121 if (!PagePrivate(page)) {
1122 /*
1123 * impossible to be !PagePrivate(page) for
1124 * the current restriction as well if
1125 * the page is already in compressed_pages[].
1126 */
1127 DBG_BUGON(!justfound);
1128
1129 justfound = 0;
1130 set_page_private(page, (unsigned long)pcl);
1131 SetPagePrivate(page);
1132 }
1133
1134 /* no need to submit io if it is already up-to-date */
1135 if (PageUptodate(page)) {
1136 unlock_page(page);
1137 page = NULL;
1138 }
1139 goto out;
1140 }
1141
1142 /*
1143 * the managed page has been truncated, it's unsafe to
1144 * reuse this one, let's allocate a new cache-managed page.
1145 */
1146 DBG_BUGON(page->mapping);
1147 DBG_BUGON(!justfound);
1148
1149 tocache = true;
1150 unlock_page(page);
1151 put_page(page);
1152 out_allocpage:
1153 page = erofs_allocpage(pagepool, gfp | __GFP_NOFAIL);
1154 if (oldpage != cmpxchg(&pcl->compressed_pages[nr], oldpage, page)) {
1155 erofs_pagepool_add(pagepool, page);
1156 cond_resched();
1157 goto repeat;
1158 }
1159 out_tocache:
1160 if (!tocache || add_to_page_cache_lru(page, mc, index + nr, gfp)) {
1161 /* turn into temporary page if fails (1 ref) */
1162 set_page_private(page, Z_EROFS_SHORTLIVED_PAGE);
1163 goto out;
1164 }
1165 attach_page_private(page, pcl);
1166 /* drop a refcount added by allocpage (then we have 2 refs here) */
1167 put_page(page);
1168
1169 out: /* the only exit (for tracing and debugging) */
1170 return page;
1171 }
1172
1173 static struct z_erofs_decompressqueue *
jobqueue_init(struct super_block * sb,struct z_erofs_decompressqueue * fgq,bool * fg)1174 jobqueue_init(struct super_block *sb,
1175 struct z_erofs_decompressqueue *fgq, bool *fg)
1176 {
1177 struct z_erofs_decompressqueue *q;
1178
1179 if (fg && !*fg) {
1180 q = kvzalloc(sizeof(*q), GFP_KERNEL | __GFP_NOWARN);
1181 if (!q) {
1182 *fg = true;
1183 goto fg_out;
1184 }
1185 INIT_WORK(&q->u.work, z_erofs_decompressqueue_work);
1186 } else {
1187 fg_out:
1188 q = fgq;
1189 init_waitqueue_head(&fgq->u.wait);
1190 atomic_set(&fgq->pending_bios, 0);
1191 }
1192 q->sb = sb;
1193 q->head = Z_EROFS_PCLUSTER_TAIL_CLOSED;
1194 return q;
1195 }
1196
1197 /* define decompression jobqueue types */
1198 enum {
1199 JQ_BYPASS,
1200 JQ_SUBMIT,
1201 NR_JOBQUEUES,
1202 };
1203
jobqueueset_init(struct super_block * sb,struct z_erofs_decompressqueue * q[],struct z_erofs_decompressqueue * fgq,bool * fg)1204 static void *jobqueueset_init(struct super_block *sb,
1205 struct z_erofs_decompressqueue *q[],
1206 struct z_erofs_decompressqueue *fgq, bool *fg)
1207 {
1208 /*
1209 * if managed cache is enabled, bypass jobqueue is needed,
1210 * no need to read from device for all pclusters in this queue.
1211 */
1212 q[JQ_BYPASS] = jobqueue_init(sb, fgq + JQ_BYPASS, NULL);
1213 q[JQ_SUBMIT] = jobqueue_init(sb, fgq + JQ_SUBMIT, fg);
1214
1215 return tagptr_cast_ptr(tagptr_fold(tagptr1_t, q[JQ_SUBMIT], *fg));
1216 }
1217
move_to_bypass_jobqueue(struct z_erofs_pcluster * pcl,z_erofs_next_pcluster_t qtail[],z_erofs_next_pcluster_t owned_head)1218 static void move_to_bypass_jobqueue(struct z_erofs_pcluster *pcl,
1219 z_erofs_next_pcluster_t qtail[],
1220 z_erofs_next_pcluster_t owned_head)
1221 {
1222 z_erofs_next_pcluster_t *const submit_qtail = qtail[JQ_SUBMIT];
1223 z_erofs_next_pcluster_t *const bypass_qtail = qtail[JQ_BYPASS];
1224
1225 DBG_BUGON(owned_head == Z_EROFS_PCLUSTER_TAIL_CLOSED);
1226 if (owned_head == Z_EROFS_PCLUSTER_TAIL)
1227 owned_head = Z_EROFS_PCLUSTER_TAIL_CLOSED;
1228
1229 WRITE_ONCE(pcl->next, Z_EROFS_PCLUSTER_TAIL_CLOSED);
1230
1231 WRITE_ONCE(*submit_qtail, owned_head);
1232 WRITE_ONCE(*bypass_qtail, &pcl->next);
1233
1234 qtail[JQ_BYPASS] = &pcl->next;
1235 }
1236
z_erofs_submit_queue(struct super_block * sb,struct z_erofs_decompress_frontend * f,struct page ** pagepool,struct z_erofs_decompressqueue * fgq,bool * force_fg)1237 static void z_erofs_submit_queue(struct super_block *sb,
1238 struct z_erofs_decompress_frontend *f,
1239 struct page **pagepool,
1240 struct z_erofs_decompressqueue *fgq,
1241 bool *force_fg)
1242 {
1243 struct erofs_sb_info *const sbi = EROFS_SB(sb);
1244 z_erofs_next_pcluster_t qtail[NR_JOBQUEUES];
1245 struct z_erofs_decompressqueue *q[NR_JOBQUEUES];
1246 void *bi_private;
1247 z_erofs_next_pcluster_t owned_head = f->clt.owned_head;
1248 /* bio is NULL initially, so no need to initialize last_{index,bdev} */
1249 pgoff_t last_index;
1250 struct block_device *last_bdev;
1251 unsigned int nr_bios = 0;
1252 struct bio *bio = NULL;
1253
1254 bi_private = jobqueueset_init(sb, q, fgq, force_fg);
1255 qtail[JQ_BYPASS] = &q[JQ_BYPASS]->head;
1256 qtail[JQ_SUBMIT] = &q[JQ_SUBMIT]->head;
1257
1258 /* by default, all need io submission */
1259 q[JQ_SUBMIT]->head = owned_head;
1260
1261 do {
1262 struct erofs_map_dev mdev;
1263 struct z_erofs_pcluster *pcl;
1264 pgoff_t cur, end;
1265 unsigned int i = 0;
1266 bool bypass = true;
1267
1268 /* no possible 'owned_head' equals the following */
1269 DBG_BUGON(owned_head == Z_EROFS_PCLUSTER_TAIL_CLOSED);
1270 DBG_BUGON(owned_head == Z_EROFS_PCLUSTER_NIL);
1271
1272 pcl = container_of(owned_head, struct z_erofs_pcluster, next);
1273
1274 /* no device id here, thus it will always succeed */
1275 mdev = (struct erofs_map_dev) {
1276 .m_pa = blknr_to_addr(pcl->obj.index),
1277 };
1278 (void)erofs_map_dev(sb, &mdev);
1279
1280 cur = erofs_blknr(mdev.m_pa);
1281 end = cur + pcl->pclusterpages;
1282
1283 /* close the main owned chain at first */
1284 owned_head = cmpxchg(&pcl->next, Z_EROFS_PCLUSTER_TAIL,
1285 Z_EROFS_PCLUSTER_TAIL_CLOSED);
1286
1287 do {
1288 struct page *page;
1289
1290 page = pickup_page_for_submission(pcl, i++, pagepool,
1291 MNGD_MAPPING(sbi),
1292 GFP_NOFS);
1293 if (!page)
1294 continue;
1295
1296 if (bio && (cur != last_index + 1 ||
1297 last_bdev != mdev.m_bdev)) {
1298 submit_bio_retry:
1299 submit_bio(bio);
1300 bio = NULL;
1301 }
1302
1303 if (!bio) {
1304 bio = bio_alloc(GFP_NOIO, BIO_MAX_VECS);
1305 bio->bi_end_io = z_erofs_decompressqueue_endio;
1306
1307 bio_set_dev(bio, mdev.m_bdev);
1308 last_bdev = mdev.m_bdev;
1309 bio->bi_iter.bi_sector = (sector_t)cur <<
1310 LOG_SECTORS_PER_BLOCK;
1311 bio->bi_private = bi_private;
1312 bio->bi_opf = REQ_OP_READ;
1313 if (f->readahead)
1314 bio->bi_opf |= REQ_RAHEAD;
1315 ++nr_bios;
1316 }
1317
1318 if (bio_add_page(bio, page, PAGE_SIZE, 0) < PAGE_SIZE)
1319 goto submit_bio_retry;
1320
1321 last_index = cur;
1322 bypass = false;
1323 } while (++cur < end);
1324
1325 if (!bypass)
1326 qtail[JQ_SUBMIT] = &pcl->next;
1327 else
1328 move_to_bypass_jobqueue(pcl, qtail, owned_head);
1329 } while (owned_head != Z_EROFS_PCLUSTER_TAIL);
1330
1331 if (bio)
1332 submit_bio(bio);
1333
1334 /*
1335 * although background is preferred, no one is pending for submission.
1336 * don't issue workqueue for decompression but drop it directly instead.
1337 */
1338 if (!*force_fg && !nr_bios) {
1339 kvfree(q[JQ_SUBMIT]);
1340 return;
1341 }
1342 z_erofs_decompress_kickoff(q[JQ_SUBMIT], *force_fg, nr_bios);
1343 }
1344
z_erofs_runqueue(struct super_block * sb,struct z_erofs_decompress_frontend * f,struct page ** pagepool,bool force_fg)1345 static void z_erofs_runqueue(struct super_block *sb,
1346 struct z_erofs_decompress_frontend *f,
1347 struct page **pagepool, bool force_fg)
1348 {
1349 struct z_erofs_decompressqueue io[NR_JOBQUEUES];
1350
1351 if (f->clt.owned_head == Z_EROFS_PCLUSTER_TAIL)
1352 return;
1353 z_erofs_submit_queue(sb, f, pagepool, io, &force_fg);
1354
1355 /* handle bypass queue (no i/o pclusters) immediately */
1356 z_erofs_decompress_queue(&io[JQ_BYPASS], pagepool);
1357
1358 if (!force_fg)
1359 return;
1360
1361 /* wait until all bios are completed */
1362 io_wait_event(io[JQ_SUBMIT].u.wait,
1363 !atomic_read(&io[JQ_SUBMIT].pending_bios));
1364
1365 /* handle synchronous decompress queue in the caller context */
1366 z_erofs_decompress_queue(&io[JQ_SUBMIT], pagepool);
1367 }
1368
1369 /*
1370 * Since partial uptodate is still unimplemented for now, we have to use
1371 * approximate readmore strategies as a start.
1372 */
z_erofs_pcluster_readmore(struct z_erofs_decompress_frontend * f,struct readahead_control * rac,erofs_off_t end,struct page ** pagepool,bool backmost)1373 static void z_erofs_pcluster_readmore(struct z_erofs_decompress_frontend *f,
1374 struct readahead_control *rac,
1375 erofs_off_t end,
1376 struct page **pagepool,
1377 bool backmost)
1378 {
1379 struct inode *inode = f->inode;
1380 struct erofs_map_blocks *map = &f->map;
1381 erofs_off_t cur;
1382 int err;
1383
1384 if (backmost) {
1385 map->m_la = end;
1386 err = z_erofs_map_blocks_iter(inode, map,
1387 EROFS_GET_BLOCKS_READMORE);
1388 if (err)
1389 return;
1390
1391 /* expend ra for the trailing edge if readahead */
1392 if (rac) {
1393 loff_t newstart = readahead_pos(rac);
1394
1395 cur = round_up(map->m_la + map->m_llen, PAGE_SIZE);
1396 readahead_expand(rac, newstart, cur - newstart);
1397 return;
1398 }
1399 end = round_up(end, PAGE_SIZE);
1400 } else {
1401 end = round_up(map->m_la, PAGE_SIZE);
1402
1403 if (!map->m_llen)
1404 return;
1405 }
1406
1407 cur = map->m_la + map->m_llen - 1;
1408 while (cur >= end) {
1409 pgoff_t index = cur >> PAGE_SHIFT;
1410 struct page *page;
1411
1412 page = erofs_grab_cache_page_nowait(inode->i_mapping, index);
1413 if (!page)
1414 goto skip;
1415
1416 if (PageUptodate(page)) {
1417 unlock_page(page);
1418 put_page(page);
1419 goto skip;
1420 }
1421
1422 err = z_erofs_do_read_page(f, page, pagepool);
1423 if (err)
1424 erofs_err(inode->i_sb,
1425 "readmore error at page %lu @ nid %llu",
1426 index, EROFS_I(inode)->nid);
1427 put_page(page);
1428 skip:
1429 if (cur < PAGE_SIZE)
1430 break;
1431 cur = (index << PAGE_SHIFT) - 1;
1432 }
1433 }
1434
z_erofs_readpage(struct file * file,struct page * page)1435 static int z_erofs_readpage(struct file *file, struct page *page)
1436 {
1437 struct inode *const inode = page->mapping->host;
1438 struct z_erofs_decompress_frontend f = DECOMPRESS_FRONTEND_INIT(inode);
1439 struct page *pagepool = NULL;
1440 int err;
1441
1442 trace_erofs_readpage(page, false);
1443 f.headoffset = (erofs_off_t)page->index << PAGE_SHIFT;
1444
1445 z_erofs_pcluster_readmore(&f, NULL, f.headoffset + PAGE_SIZE - 1,
1446 &pagepool, true);
1447 err = z_erofs_do_read_page(&f, page, &pagepool);
1448 z_erofs_pcluster_readmore(&f, NULL, 0, &pagepool, false);
1449
1450 (void)z_erofs_collector_end(&f.clt);
1451
1452 /* if some compressed cluster ready, need submit them anyway */
1453 z_erofs_runqueue(inode->i_sb, &f, &pagepool, true);
1454
1455 if (err)
1456 erofs_err(inode->i_sb, "failed to read, err [%d]", err);
1457
1458 if (f.map.mpage)
1459 put_page(f.map.mpage);
1460
1461 erofs_release_pages(&pagepool);
1462 return err;
1463 }
1464
z_erofs_readahead(struct readahead_control * rac)1465 static void z_erofs_readahead(struct readahead_control *rac)
1466 {
1467 struct inode *const inode = rac->mapping->host;
1468 struct erofs_sb_info *const sbi = EROFS_I_SB(inode);
1469 struct z_erofs_decompress_frontend f = DECOMPRESS_FRONTEND_INIT(inode);
1470 struct page *pagepool = NULL, *head = NULL, *page;
1471 unsigned int nr_pages;
1472
1473 f.readahead = true;
1474 f.headoffset = readahead_pos(rac);
1475
1476 z_erofs_pcluster_readmore(&f, rac, f.headoffset +
1477 readahead_length(rac) - 1, &pagepool, true);
1478 nr_pages = readahead_count(rac);
1479 trace_erofs_readpages(inode, readahead_index(rac), nr_pages, false);
1480
1481 while ((page = readahead_page(rac))) {
1482 set_page_private(page, (unsigned long)head);
1483 head = page;
1484 }
1485
1486 while (head) {
1487 struct page *page = head;
1488 int err;
1489
1490 /* traversal in reverse order */
1491 head = (void *)page_private(page);
1492
1493 err = z_erofs_do_read_page(&f, page, &pagepool);
1494 if (err)
1495 erofs_err(inode->i_sb,
1496 "readahead error at page %lu @ nid %llu",
1497 page->index, EROFS_I(inode)->nid);
1498 put_page(page);
1499 }
1500 z_erofs_pcluster_readmore(&f, rac, 0, &pagepool, false);
1501 (void)z_erofs_collector_end(&f.clt);
1502
1503 z_erofs_runqueue(inode->i_sb, &f, &pagepool,
1504 sbi->opt.readahead_sync_decompress &&
1505 nr_pages <= sbi->opt.max_sync_decompress_pages);
1506 if (f.map.mpage)
1507 put_page(f.map.mpage);
1508 erofs_release_pages(&pagepool);
1509 }
1510
1511 const struct address_space_operations z_erofs_aops = {
1512 .readpage = z_erofs_readpage,
1513 .readahead = z_erofs_readahead,
1514 };
1515