// SPDX-License-Identifier: GPL-2.0-only /* * Copyright (C) 2018 HUAWEI, Inc. * http://www.huawei.com/ * Created by Gao Xiang */ #include "zdata.h" #include "compress.h" #include #include /* * a compressed_pages[] placeholder in order to avoid * being filled with file pages for in-place decompression. */ #define PAGE_UNALLOCATED ((void *)0x5F0E4B1D) /* how to allocate cached pages for a pcluster */ enum z_erofs_cache_alloctype { DONTALLOC, /* don't allocate any cached pages */ DELAYEDALLOC, /* delayed allocation (at the time of submitting io) */ }; /* * tagged pointer with 1-bit tag for all compressed pages * tag 0 - the page is just found with an extra page reference */ typedef tagptr1_t compressed_page_t; #define tag_compressed_page_justfound(page) \ tagptr_fold(compressed_page_t, page, 1) static struct workqueue_struct *z_erofs_workqueue __read_mostly; static struct kmem_cache *pcluster_cachep __read_mostly; void z_erofs_exit_zip_subsystem(void) { destroy_workqueue(z_erofs_workqueue); kmem_cache_destroy(pcluster_cachep); } static inline int z_erofs_init_workqueue(void) { const unsigned int onlinecpus = num_possible_cpus(); const unsigned int flags = WQ_UNBOUND | WQ_HIGHPRI | WQ_CPU_INTENSIVE; /* * no need to spawn too many threads, limiting threads could minimum * scheduling overhead, perhaps per-CPU threads should be better? */ z_erofs_workqueue = alloc_workqueue("erofs_unzipd", flags, onlinecpus + onlinecpus / 4); return z_erofs_workqueue ? 0 : -ENOMEM; } static void z_erofs_pcluster_init_once(void *ptr) { struct z_erofs_pcluster *pcl = ptr; struct z_erofs_collection *cl = z_erofs_primarycollection(pcl); unsigned int i; mutex_init(&cl->lock); cl->nr_pages = 0; cl->vcnt = 0; for (i = 0; i < Z_EROFS_CLUSTER_MAX_PAGES; ++i) pcl->compressed_pages[i] = NULL; } static void z_erofs_pcluster_init_always(struct z_erofs_pcluster *pcl) { struct z_erofs_collection *cl = z_erofs_primarycollection(pcl); atomic_set(&pcl->obj.refcount, 1); DBG_BUGON(cl->nr_pages); DBG_BUGON(cl->vcnt); } int __init z_erofs_init_zip_subsystem(void) { pcluster_cachep = kmem_cache_create("erofs_compress", Z_EROFS_WORKGROUP_SIZE, 0, SLAB_RECLAIM_ACCOUNT, z_erofs_pcluster_init_once); if (pcluster_cachep) { if (!z_erofs_init_workqueue()) return 0; kmem_cache_destroy(pcluster_cachep); } return -ENOMEM; } enum z_erofs_collectmode { COLLECT_SECONDARY, COLLECT_PRIMARY, /* * The current collection was the tail of an exist chain, in addition * that the previous processed chained collections are all decided to * be hooked up to it. * A new chain will be created for the remaining collections which are * not processed yet, therefore different from COLLECT_PRIMARY_FOLLOWED, * the next collection cannot reuse the whole page safely in * the following scenario: * ________________________________________________________________ * | tail (partial) page | head (partial) page | * | (belongs to the next cl) | (belongs to the current cl) | * |_______PRIMARY_FOLLOWED_______|________PRIMARY_HOOKED___________| */ COLLECT_PRIMARY_HOOKED, COLLECT_PRIMARY_FOLLOWED_NOINPLACE, /* * The current collection has been linked with the owned chain, and * could also be linked with the remaining collections, which means * if the processing page is the tail page of the collection, thus * the current collection can safely use the whole page (since * the previous collection is under control) for in-place I/O, as * illustrated below: * ________________________________________________________________ * | tail (partial) page | head (partial) page | * | (of the current cl) | (of the previous collection) | * | PRIMARY_FOLLOWED or | | * |_____PRIMARY_HOOKED___|____________PRIMARY_FOLLOWED____________| * * [ (*) the above page can be used as inplace I/O. ] */ COLLECT_PRIMARY_FOLLOWED, }; struct z_erofs_collector { struct z_erofs_pagevec_ctor vector; struct z_erofs_pcluster *pcl, *tailpcl; struct z_erofs_collection *cl; struct page **compressedpages; z_erofs_next_pcluster_t owned_head; enum z_erofs_collectmode mode; }; struct z_erofs_decompress_frontend { struct inode *const inode; struct z_erofs_collector clt; struct erofs_map_blocks map; /* used for applying cache strategy on the fly */ bool backmost; erofs_off_t headoffset; }; #define COLLECTOR_INIT() { \ .owned_head = Z_EROFS_PCLUSTER_TAIL, \ .mode = COLLECT_PRIMARY_FOLLOWED } #define DECOMPRESS_FRONTEND_INIT(__i) { \ .inode = __i, .clt = COLLECTOR_INIT(), \ .backmost = true, } static struct page *z_pagemap_global[Z_EROFS_VMAP_GLOBAL_PAGES]; static DEFINE_MUTEX(z_pagemap_global_lock); static void preload_compressed_pages(struct z_erofs_collector *clt, struct address_space *mc, enum z_erofs_cache_alloctype type, struct list_head *pagepool) { const struct z_erofs_pcluster *pcl = clt->pcl; const unsigned int clusterpages = BIT(pcl->clusterbits); struct page **pages = clt->compressedpages; pgoff_t index = pcl->obj.index + (pages - pcl->compressed_pages); bool standalone = true; if (clt->mode < COLLECT_PRIMARY_FOLLOWED) return; for (; pages < pcl->compressed_pages + clusterpages; ++pages) { struct page *page; compressed_page_t t; /* the compressed page was loaded before */ if (READ_ONCE(*pages)) continue; page = find_get_page(mc, index); if (page) { t = tag_compressed_page_justfound(page); } else if (type == DELAYEDALLOC) { t = tagptr_init(compressed_page_t, PAGE_UNALLOCATED); } else { /* DONTALLOC */ if (standalone) clt->compressedpages = pages; standalone = false; continue; } if (!cmpxchg_relaxed(pages, NULL, tagptr_cast_ptr(t))) continue; if (page) put_page(page); } if (standalone) /* downgrade to PRIMARY_FOLLOWED_NOINPLACE */ clt->mode = COLLECT_PRIMARY_FOLLOWED_NOINPLACE; } /* called by erofs_shrinker to get rid of all compressed_pages */ int erofs_try_to_free_all_cached_pages(struct erofs_sb_info *sbi, struct erofs_workgroup *grp) { struct z_erofs_pcluster *const pcl = container_of(grp, struct z_erofs_pcluster, obj); struct address_space *const mapping = MNGD_MAPPING(sbi); const unsigned int clusterpages = BIT(pcl->clusterbits); int i; /* * refcount of workgroup is now freezed as 1, * therefore no need to worry about available decompression users. */ for (i = 0; i < clusterpages; ++i) { struct page *page = pcl->compressed_pages[i]; if (!page) continue; /* block other users from reclaiming or migrating the page */ if (!trylock_page(page)) return -EBUSY; if (page->mapping != mapping) continue; /* barrier is implied in the following 'unlock_page' */ WRITE_ONCE(pcl->compressed_pages[i], NULL); set_page_private(page, 0); ClearPagePrivate(page); unlock_page(page); put_page(page); } return 0; } int erofs_try_to_free_cached_page(struct address_space *mapping, struct page *page) { struct z_erofs_pcluster *const pcl = (void *)page_private(page); const unsigned int clusterpages = BIT(pcl->clusterbits); int ret = 0; /* 0 - busy */ if (erofs_workgroup_try_to_freeze(&pcl->obj, 1)) { unsigned int i; for (i = 0; i < clusterpages; ++i) { if (pcl->compressed_pages[i] == page) { WRITE_ONCE(pcl->compressed_pages[i], NULL); ret = 1; break; } } erofs_workgroup_unfreeze(&pcl->obj, 1); if (ret) { ClearPagePrivate(page); put_page(page); } } return ret; } /* page_type must be Z_EROFS_PAGE_TYPE_EXCLUSIVE */ static inline bool z_erofs_try_inplace_io(struct z_erofs_collector *clt, struct page *page) { struct z_erofs_pcluster *const pcl = clt->pcl; const unsigned int clusterpages = BIT(pcl->clusterbits); while (clt->compressedpages < pcl->compressed_pages + clusterpages) { if (!cmpxchg(clt->compressedpages++, NULL, page)) return true; } return false; } /* callers must be with collection lock held */ static int z_erofs_attach_page(struct z_erofs_collector *clt, struct page *page, enum z_erofs_page_type type) { int ret; bool occupied; /* give priority for inplaceio */ if (clt->mode >= COLLECT_PRIMARY && type == Z_EROFS_PAGE_TYPE_EXCLUSIVE && z_erofs_try_inplace_io(clt, page)) return 0; ret = z_erofs_pagevec_enqueue(&clt->vector, page, type, &occupied); clt->cl->vcnt += (unsigned int)ret; return ret ? 0 : -EAGAIN; } static enum z_erofs_collectmode try_to_claim_pcluster(struct z_erofs_pcluster *pcl, z_erofs_next_pcluster_t *owned_head) { /* let's claim these following types of pclusters */ retry: if (pcl->next == Z_EROFS_PCLUSTER_NIL) { /* type 1, nil pcluster */ if (cmpxchg(&pcl->next, Z_EROFS_PCLUSTER_NIL, *owned_head) != Z_EROFS_PCLUSTER_NIL) goto retry; *owned_head = &pcl->next; /* lucky, I am the followee :) */ return COLLECT_PRIMARY_FOLLOWED; } else if (pcl->next == Z_EROFS_PCLUSTER_TAIL) { /* * type 2, link to the end of a existing open chain, * be careful that its submission itself is governed * by the original owned chain. */ if (cmpxchg(&pcl->next, Z_EROFS_PCLUSTER_TAIL, *owned_head) != Z_EROFS_PCLUSTER_TAIL) goto retry; *owned_head = Z_EROFS_PCLUSTER_TAIL; return COLLECT_PRIMARY_HOOKED; } return COLLECT_PRIMARY; /* :( better luck next time */ } static int z_erofs_lookup_collection(struct z_erofs_collector *clt, struct inode *inode, struct erofs_map_blocks *map) { struct erofs_workgroup *grp; struct z_erofs_pcluster *pcl; struct z_erofs_collection *cl; unsigned int length; grp = erofs_find_workgroup(inode->i_sb, map->m_pa >> PAGE_SHIFT); if (!grp) return -ENOENT; pcl = container_of(grp, struct z_erofs_pcluster, obj); if (clt->owned_head == &pcl->next || pcl == clt->tailpcl) { DBG_BUGON(1); erofs_workgroup_put(grp); return -EFSCORRUPTED; } cl = z_erofs_primarycollection(pcl); if (cl->pageofs != (map->m_la & ~PAGE_MASK)) { DBG_BUGON(1); erofs_workgroup_put(grp); return -EFSCORRUPTED; } length = READ_ONCE(pcl->length); if (length & Z_EROFS_PCLUSTER_FULL_LENGTH) { if ((map->m_llen << Z_EROFS_PCLUSTER_LENGTH_BIT) > length) { DBG_BUGON(1); erofs_workgroup_put(grp); return -EFSCORRUPTED; } } else { unsigned int llen = map->m_llen << Z_EROFS_PCLUSTER_LENGTH_BIT; if (map->m_flags & EROFS_MAP_FULL_MAPPED) llen |= Z_EROFS_PCLUSTER_FULL_LENGTH; while (llen > length && length != cmpxchg_relaxed(&pcl->length, length, llen)) { cpu_relax(); length = READ_ONCE(pcl->length); } } mutex_lock(&cl->lock); /* used to check tail merging loop due to corrupted images */ if (clt->owned_head == Z_EROFS_PCLUSTER_TAIL) clt->tailpcl = pcl; clt->mode = try_to_claim_pcluster(pcl, &clt->owned_head); /* clean tailpcl if the current owned_head is Z_EROFS_PCLUSTER_TAIL */ if (clt->owned_head == Z_EROFS_PCLUSTER_TAIL) clt->tailpcl = NULL; clt->pcl = pcl; clt->cl = cl; return 0; } static int z_erofs_register_collection(struct z_erofs_collector *clt, struct inode *inode, struct erofs_map_blocks *map) { struct z_erofs_pcluster *pcl; struct z_erofs_collection *cl; int err; /* no available workgroup, let's allocate one */ pcl = kmem_cache_alloc(pcluster_cachep, GFP_NOFS); if (!pcl) return -ENOMEM; z_erofs_pcluster_init_always(pcl); pcl->obj.index = map->m_pa >> PAGE_SHIFT; pcl->length = (map->m_llen << Z_EROFS_PCLUSTER_LENGTH_BIT) | (map->m_flags & EROFS_MAP_FULL_MAPPED ? Z_EROFS_PCLUSTER_FULL_LENGTH : 0); if (map->m_flags & EROFS_MAP_ZIPPED) pcl->algorithmformat = Z_EROFS_COMPRESSION_LZ4; else pcl->algorithmformat = Z_EROFS_COMPRESSION_SHIFTED; pcl->clusterbits = EROFS_I(inode)->z_physical_clusterbits[0]; pcl->clusterbits -= PAGE_SHIFT; /* new pclusters should be claimed as type 1, primary and followed */ pcl->next = clt->owned_head; clt->mode = COLLECT_PRIMARY_FOLLOWED; cl = z_erofs_primarycollection(pcl); cl->pageofs = map->m_la & ~PAGE_MASK; /* * lock all primary followed works before visible to others * and mutex_trylock *never* fails for a new pcluster. */ mutex_trylock(&cl->lock); err = erofs_register_workgroup(inode->i_sb, &pcl->obj); if (err) { mutex_unlock(&cl->lock); kmem_cache_free(pcluster_cachep, pcl); return -EAGAIN; } /* used to check tail merging loop due to corrupted images */ if (clt->owned_head == Z_EROFS_PCLUSTER_TAIL) clt->tailpcl = pcl; clt->owned_head = &pcl->next; clt->pcl = pcl; clt->cl = cl; return 0; } static int z_erofs_collector_begin(struct z_erofs_collector *clt, struct inode *inode, struct erofs_map_blocks *map) { int ret; DBG_BUGON(clt->cl); /* must be Z_EROFS_PCLUSTER_TAIL or pointed to previous collection */ DBG_BUGON(clt->owned_head == Z_EROFS_PCLUSTER_NIL); DBG_BUGON(clt->owned_head == Z_EROFS_PCLUSTER_TAIL_CLOSED); if (!PAGE_ALIGNED(map->m_pa)) { DBG_BUGON(1); return -EINVAL; } repeat: ret = z_erofs_lookup_collection(clt, inode, map); if (ret == -ENOENT) { ret = z_erofs_register_collection(clt, inode, map); /* someone registered at the same time, give another try */ if (ret == -EAGAIN) { cond_resched(); goto repeat; } } if (ret) return ret; z_erofs_pagevec_ctor_init(&clt->vector, Z_EROFS_NR_INLINE_PAGEVECS, clt->cl->pagevec, clt->cl->vcnt); clt->compressedpages = clt->pcl->compressed_pages; if (clt->mode <= COLLECT_PRIMARY) /* cannot do in-place I/O */ clt->compressedpages += Z_EROFS_CLUSTER_MAX_PAGES; return 0; } /* * keep in mind that no referenced pclusters will be freed * only after a RCU grace period. */ static void z_erofs_rcu_callback(struct rcu_head *head) { struct z_erofs_collection *const cl = container_of(head, struct z_erofs_collection, rcu); kmem_cache_free(pcluster_cachep, container_of(cl, struct z_erofs_pcluster, primary_collection)); } void erofs_workgroup_free_rcu(struct erofs_workgroup *grp) { struct z_erofs_pcluster *const pcl = container_of(grp, struct z_erofs_pcluster, obj); struct z_erofs_collection *const cl = z_erofs_primarycollection(pcl); call_rcu(&cl->rcu, z_erofs_rcu_callback); } static void z_erofs_collection_put(struct z_erofs_collection *cl) { struct z_erofs_pcluster *const pcl = container_of(cl, struct z_erofs_pcluster, primary_collection); erofs_workgroup_put(&pcl->obj); } static bool z_erofs_collector_end(struct z_erofs_collector *clt) { struct z_erofs_collection *cl = clt->cl; if (!cl) return false; z_erofs_pagevec_ctor_exit(&clt->vector, false); mutex_unlock(&cl->lock); /* * if all pending pages are added, don't hold its reference * any longer if the pcluster isn't hosted by ourselves. */ if (clt->mode < COLLECT_PRIMARY_FOLLOWED_NOINPLACE) z_erofs_collection_put(cl); clt->cl = NULL; return true; } static bool should_alloc_managed_pages(struct z_erofs_decompress_frontend *fe, unsigned int cachestrategy, erofs_off_t la) { if (cachestrategy <= EROFS_ZIP_CACHE_DISABLED) return false; if (fe->backmost) return true; return cachestrategy >= EROFS_ZIP_CACHE_READAROUND && la < fe->headoffset; } static int z_erofs_do_read_page(struct z_erofs_decompress_frontend *fe, struct page *page, struct list_head *pagepool) { struct inode *const inode = fe->inode; struct erofs_sb_info *const sbi = EROFS_I_SB(inode); struct erofs_map_blocks *const map = &fe->map; struct z_erofs_collector *const clt = &fe->clt; const loff_t offset = page_offset(page); bool tight = true; enum z_erofs_cache_alloctype cache_strategy; enum z_erofs_page_type page_type; unsigned int cur, end, spiltted, index; int err = 0; /* register locked file pages as online pages in pack */ z_erofs_onlinepage_init(page); spiltted = 0; end = PAGE_SIZE; repeat: cur = end - 1; /* lucky, within the range of the current map_blocks */ if (offset + cur >= map->m_la && offset + cur < map->m_la + map->m_llen) { /* didn't get a valid collection previously (very rare) */ if (!clt->cl) goto restart_now; goto hitted; } /* go ahead the next map_blocks */ erofs_dbg("%s: [out-of-range] pos %llu", __func__, offset + cur); if (z_erofs_collector_end(clt)) fe->backmost = false; map->m_la = offset + cur; map->m_llen = 0; err = z_erofs_map_blocks_iter(inode, map, 0); if (err) goto err_out; restart_now: if (!(map->m_flags & EROFS_MAP_MAPPED)) goto hitted; err = z_erofs_collector_begin(clt, inode, map); if (err) goto err_out; /* preload all compressed pages (maybe downgrade role if necessary) */ if (should_alloc_managed_pages(fe, sbi->cache_strategy, map->m_la)) cache_strategy = DELAYEDALLOC; else cache_strategy = DONTALLOC; preload_compressed_pages(clt, MNGD_MAPPING(sbi), cache_strategy, pagepool); hitted: /* * Ensure the current partial page belongs to this submit chain rather * than other concurrent submit chains or the noio(bypass) chain since * those chains are handled asynchronously thus the page cannot be used * for inplace I/O or pagevec (should be processed in strict order.) */ tight &= (clt->mode >= COLLECT_PRIMARY_HOOKED && clt->mode != COLLECT_PRIMARY_FOLLOWED_NOINPLACE); cur = end - min_t(unsigned int, offset + end - map->m_la, end); if (!(map->m_flags & EROFS_MAP_MAPPED)) { zero_user_segment(page, cur, end); goto next_part; } /* let's derive page type */ page_type = cur ? Z_EROFS_VLE_PAGE_TYPE_HEAD : (!spiltted ? Z_EROFS_PAGE_TYPE_EXCLUSIVE : (tight ? Z_EROFS_PAGE_TYPE_EXCLUSIVE : Z_EROFS_VLE_PAGE_TYPE_TAIL_SHARED)); if (cur) tight &= (clt->mode >= COLLECT_PRIMARY_FOLLOWED); retry: err = z_erofs_attach_page(clt, page, page_type); /* should allocate an additional staging page for pagevec */ if (err == -EAGAIN) { struct page *const newpage = erofs_allocpage(pagepool, GFP_NOFS | __GFP_NOFAIL); newpage->mapping = Z_EROFS_MAPPING_STAGING; err = z_erofs_attach_page(clt, newpage, Z_EROFS_PAGE_TYPE_EXCLUSIVE); if (!err) goto retry; } if (err) goto err_out; index = page->index - (map->m_la >> PAGE_SHIFT); z_erofs_onlinepage_fixup(page, index, true); /* bump up the number of spiltted parts of a page */ ++spiltted; /* also update nr_pages */ clt->cl->nr_pages = max_t(pgoff_t, clt->cl->nr_pages, index + 1); next_part: /* can be used for verification */ map->m_llen = offset + cur - map->m_la; end = cur; if (end > 0) goto repeat; out: z_erofs_onlinepage_endio(page); erofs_dbg("%s, finish page: %pK spiltted: %u map->m_llen %llu", __func__, page, spiltted, map->m_llen); return err; /* if some error occurred while processing this page */ err_out: SetPageError(page); goto out; } static void z_erofs_decompress_kickoff(struct z_erofs_decompressqueue *io, bool sync, int bios) { /* wake up the caller thread for sync decompression */ if (sync) { unsigned long flags; spin_lock_irqsave(&io->u.wait.lock, flags); if (!atomic_add_return(bios, &io->pending_bios)) wake_up_locked(&io->u.wait); spin_unlock_irqrestore(&io->u.wait.lock, flags); return; } if (!atomic_add_return(bios, &io->pending_bios)) queue_work(z_erofs_workqueue, &io->u.work); } static void z_erofs_decompressqueue_endio(struct bio *bio) { tagptr1_t t = tagptr_init(tagptr1_t, bio->bi_private); struct z_erofs_decompressqueue *q = tagptr_unfold_ptr(t); blk_status_t err = bio->bi_status; struct bio_vec *bvec; struct bvec_iter_all iter_all; bio_for_each_segment_all(bvec, bio, iter_all) { struct page *page = bvec->bv_page; DBG_BUGON(PageUptodate(page)); DBG_BUGON(!page->mapping); if (err) SetPageError(page); if (erofs_page_is_managed(EROFS_SB(q->sb), page)) { if (!err) SetPageUptodate(page); unlock_page(page); } } z_erofs_decompress_kickoff(q, tagptr_unfold_tags(t), -1); bio_put(bio); } static int z_erofs_decompress_pcluster(struct super_block *sb, struct z_erofs_pcluster *pcl, struct list_head *pagepool) { struct erofs_sb_info *const sbi = EROFS_SB(sb); const unsigned int clusterpages = BIT(pcl->clusterbits); struct z_erofs_pagevec_ctor ctor; unsigned int i, outputsize, llen, nr_pages; struct page *pages_onstack[Z_EROFS_VMAP_ONSTACK_PAGES]; struct page **pages, **compressed_pages, *page; enum z_erofs_page_type page_type; bool overlapped, partial; struct z_erofs_collection *cl; int err; might_sleep(); cl = z_erofs_primarycollection(pcl); DBG_BUGON(!READ_ONCE(cl->nr_pages)); mutex_lock(&cl->lock); nr_pages = cl->nr_pages; if (nr_pages <= Z_EROFS_VMAP_ONSTACK_PAGES) { pages = pages_onstack; } else if (nr_pages <= Z_EROFS_VMAP_GLOBAL_PAGES && mutex_trylock(&z_pagemap_global_lock)) { pages = z_pagemap_global; } else { gfp_t gfp_flags = GFP_KERNEL; if (nr_pages > Z_EROFS_VMAP_GLOBAL_PAGES) gfp_flags |= __GFP_NOFAIL; pages = kvmalloc_array(nr_pages, sizeof(struct page *), gfp_flags); /* fallback to global pagemap for the lowmem scenario */ if (!pages) { mutex_lock(&z_pagemap_global_lock); pages = z_pagemap_global; } } for (i = 0; i < nr_pages; ++i) pages[i] = NULL; err = 0; z_erofs_pagevec_ctor_init(&ctor, Z_EROFS_NR_INLINE_PAGEVECS, cl->pagevec, 0); for (i = 0; i < cl->vcnt; ++i) { unsigned int pagenr; page = z_erofs_pagevec_dequeue(&ctor, &page_type); /* all pages in pagevec ought to be valid */ DBG_BUGON(!page); DBG_BUGON(!page->mapping); if (z_erofs_put_stagingpage(pagepool, page)) continue; if (page_type == Z_EROFS_VLE_PAGE_TYPE_HEAD) pagenr = 0; else pagenr = z_erofs_onlinepage_index(page); DBG_BUGON(pagenr >= nr_pages); /* * currently EROFS doesn't support multiref(dedup), * so here erroring out one multiref page. */ if (pages[pagenr]) { DBG_BUGON(1); SetPageError(pages[pagenr]); z_erofs_onlinepage_endio(pages[pagenr]); err = -EFSCORRUPTED; } pages[pagenr] = page; } z_erofs_pagevec_ctor_exit(&ctor, true); overlapped = false; compressed_pages = pcl->compressed_pages; for (i = 0; i < clusterpages; ++i) { unsigned int pagenr; page = compressed_pages[i]; /* all compressed pages ought to be valid */ DBG_BUGON(!page); DBG_BUGON(!page->mapping); if (!z_erofs_page_is_staging(page)) { if (erofs_page_is_managed(sbi, page)) { if (!PageUptodate(page)) err = -EIO; continue; } /* * only if non-head page can be selected * for inplace decompression */ pagenr = z_erofs_onlinepage_index(page); DBG_BUGON(pagenr >= nr_pages); if (pages[pagenr]) { DBG_BUGON(1); SetPageError(pages[pagenr]); z_erofs_onlinepage_endio(pages[pagenr]); err = -EFSCORRUPTED; } pages[pagenr] = page; overlapped = true; } /* PG_error needs checking for inplaced and staging pages */ if (PageError(page)) { DBG_BUGON(PageUptodate(page)); err = -EIO; } } if (err) goto out; llen = pcl->length >> Z_EROFS_PCLUSTER_LENGTH_BIT; if (nr_pages << PAGE_SHIFT >= cl->pageofs + llen) { outputsize = llen; partial = !(pcl->length & Z_EROFS_PCLUSTER_FULL_LENGTH); } else { outputsize = (nr_pages << PAGE_SHIFT) - cl->pageofs; partial = true; } err = z_erofs_decompress(&(struct z_erofs_decompress_req) { .sb = sb, .in = compressed_pages, .out = pages, .pageofs_out = cl->pageofs, .inputsize = PAGE_SIZE, .outputsize = outputsize, .alg = pcl->algorithmformat, .inplace_io = overlapped, .partial_decoding = partial }, pagepool); out: /* must handle all compressed pages before endding pages */ for (i = 0; i < clusterpages; ++i) { page = compressed_pages[i]; if (erofs_page_is_managed(sbi, page)) continue; /* recycle all individual staging pages */ (void)z_erofs_put_stagingpage(pagepool, page); WRITE_ONCE(compressed_pages[i], NULL); } for (i = 0; i < nr_pages; ++i) { page = pages[i]; if (!page) continue; DBG_BUGON(!page->mapping); /* recycle all individual staging pages */ if (z_erofs_put_stagingpage(pagepool, page)) continue; if (err < 0) SetPageError(page); z_erofs_onlinepage_endio(page); } if (pages == z_pagemap_global) mutex_unlock(&z_pagemap_global_lock); else if (pages != pages_onstack) kvfree(pages); cl->nr_pages = 0; cl->vcnt = 0; /* all cl locks MUST be taken before the following line */ WRITE_ONCE(pcl->next, Z_EROFS_PCLUSTER_NIL); /* all cl locks SHOULD be released right now */ mutex_unlock(&cl->lock); z_erofs_collection_put(cl); return err; } static void z_erofs_decompress_queue(const struct z_erofs_decompressqueue *io, struct list_head *pagepool) { z_erofs_next_pcluster_t owned = io->head; while (owned != Z_EROFS_PCLUSTER_TAIL_CLOSED) { struct z_erofs_pcluster *pcl; /* no possible that 'owned' equals Z_EROFS_WORK_TPTR_TAIL */ DBG_BUGON(owned == Z_EROFS_PCLUSTER_TAIL); /* no possible that 'owned' equals NULL */ DBG_BUGON(owned == Z_EROFS_PCLUSTER_NIL); pcl = container_of(owned, struct z_erofs_pcluster, next); owned = READ_ONCE(pcl->next); z_erofs_decompress_pcluster(io->sb, pcl, pagepool); } } static void z_erofs_decompressqueue_work(struct work_struct *work) { struct z_erofs_decompressqueue *bgq = container_of(work, struct z_erofs_decompressqueue, u.work); LIST_HEAD(pagepool); DBG_BUGON(bgq->head == Z_EROFS_PCLUSTER_TAIL_CLOSED); z_erofs_decompress_queue(bgq, &pagepool); put_pages_list(&pagepool); kvfree(bgq); } static struct page *pickup_page_for_submission(struct z_erofs_pcluster *pcl, unsigned int nr, struct list_head *pagepool, struct address_space *mc, gfp_t gfp) { const pgoff_t index = pcl->obj.index; bool tocache = false; struct address_space *mapping; struct page *oldpage, *page; compressed_page_t t; int justfound; repeat: page = READ_ONCE(pcl->compressed_pages[nr]); oldpage = page; if (!page) goto out_allocpage; /* * the cached page has not been allocated and * an placeholder is out there, prepare it now. */ if (page == PAGE_UNALLOCATED) { tocache = true; goto out_allocpage; } /* process the target tagged pointer */ t = tagptr_init(compressed_page_t, page); justfound = tagptr_unfold_tags(t); page = tagptr_unfold_ptr(t); mapping = READ_ONCE(page->mapping); /* * unmanaged (file) pages are all locked solidly, * therefore it is impossible for `mapping' to be NULL. */ if (mapping && mapping != mc) /* ought to be unmanaged pages */ goto out; lock_page(page); /* only true if page reclaim goes wrong, should never happen */ DBG_BUGON(justfound && PagePrivate(page)); /* the page is still in manage cache */ if (page->mapping == mc) { WRITE_ONCE(pcl->compressed_pages[nr], page); ClearPageError(page); if (!PagePrivate(page)) { /* * impossible to be !PagePrivate(page) for * the current restriction as well if * the page is already in compressed_pages[]. */ DBG_BUGON(!justfound); justfound = 0; set_page_private(page, (unsigned long)pcl); SetPagePrivate(page); } /* no need to submit io if it is already up-to-date */ if (PageUptodate(page)) { unlock_page(page); page = NULL; } goto out; } /* * the managed page has been truncated, it's unsafe to * reuse this one, let's allocate a new cache-managed page. */ DBG_BUGON(page->mapping); DBG_BUGON(!justfound); tocache = true; unlock_page(page); put_page(page); out_allocpage: page = erofs_allocpage(pagepool, gfp | __GFP_NOFAIL); if (!tocache || add_to_page_cache_lru(page, mc, index + nr, gfp)) { /* non-LRU / non-movable temporary page is needed */ page->mapping = Z_EROFS_MAPPING_STAGING; tocache = false; } if (oldpage != cmpxchg(&pcl->compressed_pages[nr], oldpage, page)) { if (tocache) { /* since it added to managed cache successfully */ unlock_page(page); put_page(page); } else { list_add(&page->lru, pagepool); } cond_resched(); goto repeat; } set_page_private(page, (unsigned long)pcl); SetPagePrivate(page); out: /* the only exit (for tracing and debugging) */ return page; } static struct z_erofs_decompressqueue * jobqueue_init(struct super_block *sb, struct z_erofs_decompressqueue *fgq, bool *fg) { struct z_erofs_decompressqueue *q; if (fg && !*fg) { q = kvzalloc(sizeof(*q), GFP_KERNEL | __GFP_NOWARN); if (!q) { *fg = true; goto fg_out; } INIT_WORK(&q->u.work, z_erofs_decompressqueue_work); } else { fg_out: q = fgq; init_waitqueue_head(&fgq->u.wait); atomic_set(&fgq->pending_bios, 0); } q->sb = sb; q->head = Z_EROFS_PCLUSTER_TAIL_CLOSED; return q; } /* define decompression jobqueue types */ enum { JQ_BYPASS, JQ_SUBMIT, NR_JOBQUEUES, }; static void *jobqueueset_init(struct super_block *sb, struct z_erofs_decompressqueue *q[], struct z_erofs_decompressqueue *fgq, bool *fg) { /* * if managed cache is enabled, bypass jobqueue is needed, * no need to read from device for all pclusters in this queue. */ q[JQ_BYPASS] = jobqueue_init(sb, fgq + JQ_BYPASS, NULL); q[JQ_SUBMIT] = jobqueue_init(sb, fgq + JQ_SUBMIT, fg); return tagptr_cast_ptr(tagptr_fold(tagptr1_t, q[JQ_SUBMIT], *fg)); } static void move_to_bypass_jobqueue(struct z_erofs_pcluster *pcl, z_erofs_next_pcluster_t qtail[], z_erofs_next_pcluster_t owned_head) { z_erofs_next_pcluster_t *const submit_qtail = qtail[JQ_SUBMIT]; z_erofs_next_pcluster_t *const bypass_qtail = qtail[JQ_BYPASS]; DBG_BUGON(owned_head == Z_EROFS_PCLUSTER_TAIL_CLOSED); if (owned_head == Z_EROFS_PCLUSTER_TAIL) owned_head = Z_EROFS_PCLUSTER_TAIL_CLOSED; WRITE_ONCE(pcl->next, Z_EROFS_PCLUSTER_TAIL_CLOSED); WRITE_ONCE(*submit_qtail, owned_head); WRITE_ONCE(*bypass_qtail, &pcl->next); qtail[JQ_BYPASS] = &pcl->next; } static void z_erofs_submit_queue(struct super_block *sb, z_erofs_next_pcluster_t owned_head, struct list_head *pagepool, struct z_erofs_decompressqueue *fgq, bool *force_fg) { struct erofs_sb_info *const sbi = EROFS_SB(sb); z_erofs_next_pcluster_t qtail[NR_JOBQUEUES]; struct z_erofs_decompressqueue *q[NR_JOBQUEUES]; void *bi_private; /* since bio will be NULL, no need to initialize last_index */ pgoff_t uninitialized_var(last_index); unsigned int nr_bios = 0; struct bio *bio = NULL; bi_private = jobqueueset_init(sb, q, fgq, force_fg); qtail[JQ_BYPASS] = &q[JQ_BYPASS]->head; qtail[JQ_SUBMIT] = &q[JQ_SUBMIT]->head; /* by default, all need io submission */ q[JQ_SUBMIT]->head = owned_head; do { struct z_erofs_pcluster *pcl; pgoff_t cur, end; unsigned int i = 0; bool bypass = true; /* no possible 'owned_head' equals the following */ DBG_BUGON(owned_head == Z_EROFS_PCLUSTER_TAIL_CLOSED); DBG_BUGON(owned_head == Z_EROFS_PCLUSTER_NIL); pcl = container_of(owned_head, struct z_erofs_pcluster, next); cur = pcl->obj.index; end = cur + BIT(pcl->clusterbits); /* close the main owned chain at first */ owned_head = cmpxchg(&pcl->next, Z_EROFS_PCLUSTER_TAIL, Z_EROFS_PCLUSTER_TAIL_CLOSED); do { struct page *page; int err; page = pickup_page_for_submission(pcl, i++, pagepool, MNGD_MAPPING(sbi), GFP_NOFS); if (!page) continue; if (bio && cur != last_index + 1) { submit_bio_retry: submit_bio(bio); bio = NULL; } if (!bio) { bio = bio_alloc(GFP_NOIO, BIO_MAX_PAGES); bio->bi_end_io = z_erofs_decompressqueue_endio; bio_set_dev(bio, sb->s_bdev); bio->bi_iter.bi_sector = (sector_t)cur << LOG_SECTORS_PER_BLOCK; bio->bi_private = bi_private; bio->bi_opf = REQ_OP_READ; ++nr_bios; } err = bio_add_page(bio, page, PAGE_SIZE, 0); if (err < PAGE_SIZE) goto submit_bio_retry; last_index = cur; bypass = false; } while (++cur < end); if (!bypass) qtail[JQ_SUBMIT] = &pcl->next; else move_to_bypass_jobqueue(pcl, qtail, owned_head); } while (owned_head != Z_EROFS_PCLUSTER_TAIL); if (bio) submit_bio(bio); /* * although background is preferred, no one is pending for submission. * don't issue workqueue for decompression but drop it directly instead. */ if (!*force_fg && !nr_bios) { kvfree(q[JQ_SUBMIT]); return; } z_erofs_decompress_kickoff(q[JQ_SUBMIT], *force_fg, nr_bios); } static void z_erofs_runqueue(struct super_block *sb, struct z_erofs_collector *clt, struct list_head *pagepool, bool force_fg) { struct z_erofs_decompressqueue io[NR_JOBQUEUES]; if (clt->owned_head == Z_EROFS_PCLUSTER_TAIL) return; z_erofs_submit_queue(sb, clt->owned_head, pagepool, io, &force_fg); /* handle bypass queue (no i/o pclusters) immediately */ z_erofs_decompress_queue(&io[JQ_BYPASS], pagepool); if (!force_fg) return; /* wait until all bios are completed */ io_wait_event(io[JQ_SUBMIT].u.wait, !atomic_read(&io[JQ_SUBMIT].pending_bios)); /* handle synchronous decompress queue in the caller context */ z_erofs_decompress_queue(&io[JQ_SUBMIT], pagepool); } static int z_erofs_readpage(struct file *file, struct page *page) { struct inode *const inode = page->mapping->host; struct z_erofs_decompress_frontend f = DECOMPRESS_FRONTEND_INIT(inode); int err; LIST_HEAD(pagepool); trace_erofs_readpage(page, false); f.headoffset = (erofs_off_t)page->index << PAGE_SHIFT; err = z_erofs_do_read_page(&f, page, &pagepool); (void)z_erofs_collector_end(&f.clt); /* if some compressed cluster ready, need submit them anyway */ z_erofs_runqueue(inode->i_sb, &f.clt, &pagepool, true); if (err) erofs_err(inode->i_sb, "failed to read, err [%d]", err); if (f.map.mpage) put_page(f.map.mpage); /* clean up the remaining free pages */ put_pages_list(&pagepool); return err; } static bool should_decompress_synchronously(struct erofs_sb_info *sbi, unsigned int nr) { return nr <= sbi->max_sync_decompress_pages; } static int z_erofs_readpages(struct file *filp, struct address_space *mapping, struct list_head *pages, unsigned int nr_pages) { struct inode *const inode = mapping->host; struct erofs_sb_info *const sbi = EROFS_I_SB(inode); bool sync = should_decompress_synchronously(sbi, nr_pages); struct z_erofs_decompress_frontend f = DECOMPRESS_FRONTEND_INIT(inode); gfp_t gfp = mapping_gfp_constraint(mapping, GFP_KERNEL); struct page *head = NULL; LIST_HEAD(pagepool); trace_erofs_readpages(mapping->host, lru_to_page(pages), nr_pages, false); f.headoffset = (erofs_off_t)lru_to_page(pages)->index << PAGE_SHIFT; for (; nr_pages; --nr_pages) { struct page *page = lru_to_page(pages); prefetchw(&page->flags); list_del(&page->lru); /* * A pure asynchronous readahead is indicated if * a PG_readahead marked page is hitted at first. * Let's also do asynchronous decompression for this case. */ sync &= !(PageReadahead(page) && !head); if (add_to_page_cache_lru(page, mapping, page->index, gfp)) { list_add(&page->lru, &pagepool); continue; } set_page_private(page, (unsigned long)head); head = page; } while (head) { struct page *page = head; int err; /* traversal in reverse order */ head = (void *)page_private(page); err = z_erofs_do_read_page(&f, page, &pagepool); if (err) erofs_err(inode->i_sb, "readahead error at page %lu @ nid %llu", page->index, EROFS_I(inode)->nid); put_page(page); } (void)z_erofs_collector_end(&f.clt); z_erofs_runqueue(inode->i_sb, &f.clt, &pagepool, sync); if (f.map.mpage) put_page(f.map.mpage); /* clean up the remaining free pages */ put_pages_list(&pagepool); return 0; } const struct address_space_operations z_erofs_aops = { .readpage = z_erofs_readpage, .readpages = z_erofs_readpages, };