// SPDX-License-Identifier: GPL-2.0-only /* * Copyright (C) 2018 HUAWEI, Inc. * https://www.huawei.com/ */ #include "zdata.h" #include "compress.h" #include <linux/prefetch.h> #include <trace/events/erofs.h> /* * since pclustersize is variable for big pcluster feature, introduce slab * pools implementation for different pcluster sizes. */ struct z_erofs_pcluster_slab { struct kmem_cache *slab; unsigned int maxpages; char name[48]; }; #define _PCLP(n) { .maxpages = n } static struct z_erofs_pcluster_slab pcluster_pool[] __read_mostly = { _PCLP(1), _PCLP(4), _PCLP(16), _PCLP(64), _PCLP(128), _PCLP(Z_EROFS_PCLUSTER_MAX_PAGES) }; static void z_erofs_destroy_pcluster_pool(void) { int i; for (i = 0; i < ARRAY_SIZE(pcluster_pool); ++i) { if (!pcluster_pool[i].slab) continue; kmem_cache_destroy(pcluster_pool[i].slab); pcluster_pool[i].slab = NULL; } } static int z_erofs_create_pcluster_pool(void) { struct z_erofs_pcluster_slab *pcs; struct z_erofs_pcluster *a; unsigned int size; for (pcs = pcluster_pool; pcs < pcluster_pool + ARRAY_SIZE(pcluster_pool); ++pcs) { size = struct_size(a, compressed_pages, pcs->maxpages); sprintf(pcs->name, "erofs_pcluster-%u", pcs->maxpages); pcs->slab = kmem_cache_create(pcs->name, size, 0, SLAB_RECLAIM_ACCOUNT, NULL); if (pcs->slab) continue; z_erofs_destroy_pcluster_pool(); return -ENOMEM; } return 0; } static struct z_erofs_pcluster *z_erofs_alloc_pcluster(unsigned int nrpages) { int i; for (i = 0; i < ARRAY_SIZE(pcluster_pool); ++i) { struct z_erofs_pcluster_slab *pcs = pcluster_pool + i; struct z_erofs_pcluster *pcl; if (nrpages > pcs->maxpages) continue; pcl = kmem_cache_zalloc(pcs->slab, GFP_NOFS); if (!pcl) return ERR_PTR(-ENOMEM); pcl->pclusterpages = nrpages; return pcl; } return ERR_PTR(-EINVAL); } static void z_erofs_free_pcluster(struct z_erofs_pcluster *pcl) { int i; for (i = 0; i < ARRAY_SIZE(pcluster_pool); ++i) { struct z_erofs_pcluster_slab *pcs = pcluster_pool + i; if (pcl->pclusterpages > pcs->maxpages) continue; kmem_cache_free(pcs->slab, pcl); return; } DBG_BUGON(1); } /* how to allocate cached pages for a pcluster */ enum z_erofs_cache_alloctype { DONTALLOC, /* don't allocate any cached pages */ /* * try to use cached I/O if page allocation succeeds or fallback * to in-place I/O instead to avoid any direct reclaim. */ TRYALLOC, }; /* * 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; void z_erofs_exit_zip_subsystem(void) { destroy_workqueue(z_erofs_workqueue); z_erofs_destroy_pcluster_pool(); } static inline int z_erofs_init_workqueue(void) { const unsigned int onlinecpus = num_possible_cpus(); /* * 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", WQ_UNBOUND | WQ_HIGHPRI, onlinecpus + onlinecpus / 4); return z_erofs_workqueue ? 0 : -ENOMEM; } int __init z_erofs_init_zip_subsystem(void) { int err = z_erofs_create_pcluster_pool(); if (err) return err; err = z_erofs_init_workqueue(); if (err) z_erofs_destroy_pcluster_pool(); return err; } 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, /* * a weak form of COLLECT_PRIMARY_FOLLOWED, the difference is that it * could be dispatched into bypass queue later due to uptodated managed * pages. All related online pages cannot be reused for inplace I/O (or * pagevec) since it can be directly decoded without I/O submission. */ 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; /* a pointer used to pick up inplace I/O pages */ struct page **icpage_ptr; 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; bool readahead; /* 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 page **pagepool) { struct z_erofs_pcluster *pcl = clt->pcl; bool standalone = true; gfp_t gfp = (mapping_gfp_mask(mc) & ~__GFP_DIRECT_RECLAIM) | __GFP_NOMEMALLOC | __GFP_NORETRY | __GFP_NOWARN; struct page **pages; pgoff_t index; if (clt->mode < COLLECT_PRIMARY_FOLLOWED) return; pages = pcl->compressed_pages; index = pcl->obj.index; for (; index < pcl->obj.index + pcl->pclusterpages; ++index, ++pages) { struct page *page; compressed_page_t t; struct page *newpage = NULL; /* 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 { /* I/O is needed, no possible to decompress directly */ standalone = false; switch (type) { case TRYALLOC: newpage = erofs_allocpage(pagepool, gfp); if (!newpage) continue; set_page_private(newpage, Z_EROFS_PREALLOCATED_PAGE); t = tag_compressed_page_justfound(newpage); break; default: /* DONTALLOC */ continue; } } if (!cmpxchg_relaxed(pages, NULL, tagptr_cast_ptr(t))) continue; if (page) put_page(page); else if (newpage) erofs_pagepool_add(pagepool, newpage); } /* * don't do inplace I/O if all compressed pages are available in * managed cache since it can be moved to the bypass queue instead. */ if (standalone) 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); int i; /* * refcount of workgroup is now freezed as 1, * therefore no need to worry about available decompression users. */ for (i = 0; i < pcl->pclusterpages; ++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 (!erofs_page_is_managed(sbi, page)) continue; /* barrier is implied in the following 'unlock_page' */ WRITE_ONCE(pcl->compressed_pages[i], NULL); detach_page_private(page); unlock_page(page); } return 0; } int erofs_try_to_free_cached_page(struct page *page) { struct z_erofs_pcluster *const pcl = (void *)page_private(page); int ret = 0; /* 0 - busy */ if (erofs_workgroup_try_to_freeze(&pcl->obj, 1)) { unsigned int i; for (i = 0; i < pcl->pclusterpages; ++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) detach_page_private(page); } return ret; } /* page_type must be Z_EROFS_PAGE_TYPE_EXCLUSIVE */ static bool z_erofs_try_inplace_io(struct z_erofs_collector *clt, struct page *page) { struct z_erofs_pcluster *const pcl = clt->pcl; while (clt->icpage_ptr > pcl->compressed_pages) if (!cmpxchg(--clt->icpage_ptr, 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, bool pvec_safereuse) { int ret; /* 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, pvec_safereuse); clt->cl->vcnt += (unsigned int)ret; return ret ? 0 : -EAGAIN; } static void z_erofs_try_to_claim_pcluster(struct z_erofs_collector *clt) { struct z_erofs_pcluster *pcl = clt->pcl; z_erofs_next_pcluster_t *owned_head = &clt->owned_head; /* type 1, nil pcluster (this pcluster doesn't belong to any chain.) */ if (cmpxchg(&pcl->next, Z_EROFS_PCLUSTER_NIL, *owned_head) == Z_EROFS_PCLUSTER_NIL) { *owned_head = &pcl->next; /* so we can attach this pcluster to our submission chain. */ clt->mode = COLLECT_PRIMARY_FOLLOWED; return; } /* * type 2, link to the end of an existing open chain, be careful * that its submission is controlled by the original attached chain. */ if (cmpxchg(&pcl->next, Z_EROFS_PCLUSTER_TAIL, *owned_head) == Z_EROFS_PCLUSTER_TAIL) { *owned_head = Z_EROFS_PCLUSTER_TAIL; clt->mode = COLLECT_PRIMARY_HOOKED; clt->tailpcl = NULL; return; } /* type 3, it belongs to a chain, but it isn't the end of the chain */ clt->mode = COLLECT_PRIMARY; } static int z_erofs_lookup_collection(struct z_erofs_collector *clt, struct inode *inode, struct erofs_map_blocks *map) { struct z_erofs_pcluster *pcl = clt->pcl; struct z_erofs_collection *cl; unsigned int length; /* to avoid unexpected loop formed by corrupted images */ if (clt->owned_head == &pcl->next || pcl == clt->tailpcl) { DBG_BUGON(1); return -EFSCORRUPTED; } cl = z_erofs_primarycollection(pcl); if (cl->pageofs != (map->m_la & ~PAGE_MASK)) { DBG_BUGON(1); 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); 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; z_erofs_try_to_claim_pcluster(clt); 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; struct erofs_workgroup *grp; int err; if (!(map->m_flags & EROFS_MAP_ENCODED)) { DBG_BUGON(1); return -EFSCORRUPTED; } /* no available pcluster, let's allocate one */ pcl = z_erofs_alloc_pcluster(map->m_plen >> PAGE_SHIFT); if (IS_ERR(pcl)) return PTR_ERR(pcl); atomic_set(&pcl->obj.refcount, 1); pcl->obj.index = map->m_pa >> PAGE_SHIFT; pcl->algorithmformat = map->m_algorithmformat; pcl->length = (map->m_llen << Z_EROFS_PCLUSTER_LENGTH_BIT) | (map->m_flags & EROFS_MAP_FULL_MAPPED ? Z_EROFS_PCLUSTER_FULL_LENGTH : 0); /* 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_init(&cl->lock); DBG_BUGON(!mutex_trylock(&cl->lock)); grp = erofs_insert_workgroup(inode->i_sb, &pcl->obj); if (IS_ERR(grp)) { err = PTR_ERR(grp); goto err_out; } if (grp != &pcl->obj) { clt->pcl = container_of(grp, struct z_erofs_pcluster, obj); err = -EEXIST; goto err_out; } /* 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; err_out: mutex_unlock(&cl->lock); z_erofs_free_pcluster(pcl); return err; } static int z_erofs_collector_begin(struct z_erofs_collector *clt, struct inode *inode, struct erofs_map_blocks *map) { struct erofs_workgroup *grp; 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; } grp = erofs_find_workgroup(inode->i_sb, map->m_pa >> PAGE_SHIFT); if (grp) { clt->pcl = container_of(grp, struct z_erofs_pcluster, obj); } else { ret = z_erofs_register_collection(clt, inode, map); if (!ret) goto out; if (ret != -EEXIST) return ret; } ret = z_erofs_lookup_collection(clt, inode, map); if (ret) { erofs_workgroup_put(&clt->pcl->obj); return ret; } out: z_erofs_pagevec_ctor_init(&clt->vector, Z_EROFS_NR_INLINE_PAGEVECS, clt->cl->pagevec, clt->cl->vcnt); /* since file-backed online pages are traversed in reverse order */ clt->icpage_ptr = clt->pcl->compressed_pages + clt->pcl->pclusterpages; 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); z_erofs_free_pcluster(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 page **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->opt.cache_strategy, map->m_la)) cache_strategy = TRYALLOC; 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, clt->mode >= COLLECT_PRIMARY_FOLLOWED); /* should allocate an additional short-lived page for pagevec */ if (err == -EAGAIN) { struct page *const newpage = alloc_page(GFP_NOFS | __GFP_NOFAIL); set_page_private(newpage, Z_EROFS_SHORTLIVED_PAGE); err = z_erofs_attach_page(clt, newpage, Z_EROFS_PAGE_TYPE_EXCLUSIVE, true); 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_decompressqueue_work(struct work_struct *work); static void z_erofs_decompress_kickoff(struct z_erofs_decompressqueue *io, bool sync, int bios) { struct erofs_sb_info *const sbi = EROFS_SB(io->sb); /* 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)) return; /* Use workqueue and sync decompression for atomic contexts only */ if (in_atomic() || irqs_disabled()) { queue_work(z_erofs_workqueue, &io->u.work); sbi->opt.readahead_sync_decompress = true; return; } z_erofs_decompressqueue_work(&io->u.work); } static bool z_erofs_page_is_invalidated(struct page *page) { return !page->mapping && !z_erofs_is_shortlived_page(page); } 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(z_erofs_page_is_invalidated(page)); 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 page **pagepool) { struct erofs_sb_info *const sbi = EROFS_SB(sb); struct z_erofs_pagevec_ctor ctor; unsigned int i, inputsize, 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(z_erofs_page_is_invalidated(page)); if (z_erofs_put_shortlivedpage(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 < pcl->pclusterpages; ++i) { unsigned int pagenr; page = compressed_pages[i]; /* all compressed pages ought to be valid */ DBG_BUGON(!page); DBG_BUGON(z_erofs_page_is_invalidated(page)); if (!z_erofs_is_shortlived_page(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 all non-managed 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; } inputsize = pcl->pclusterpages * PAGE_SIZE; err = z_erofs_decompress(&(struct z_erofs_decompress_req) { .sb = sb, .in = compressed_pages, .out = pages, .pageofs_out = cl->pageofs, .inputsize = inputsize, .outputsize = outputsize, .alg = pcl->algorithmformat, .inplace_io = overlapped, .partial_decoding = partial }, pagepool); out: /* must handle all compressed pages before ending pages */ for (i = 0; i < pcl->pclusterpages; ++i) { page = compressed_pages[i]; if (erofs_page_is_managed(sbi, page)) continue; /* recycle all individual short-lived pages */ (void)z_erofs_put_shortlivedpage(pagepool, page); WRITE_ONCE(compressed_pages[i], NULL); } for (i = 0; i < nr_pages; ++i) { page = pages[i]; if (!page) continue; DBG_BUGON(z_erofs_page_is_invalidated(page)); /* recycle all individual short-lived pages */ if (z_erofs_put_shortlivedpage(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 page **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); struct page *pagepool = NULL; DBG_BUGON(bgq->head == Z_EROFS_PCLUSTER_TAIL_CLOSED); z_erofs_decompress_queue(bgq, &pagepool); erofs_release_pages(&pagepool); kvfree(bgq); } static struct page *pickup_page_for_submission(struct z_erofs_pcluster *pcl, unsigned int nr, struct page **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; /* process the target tagged pointer */ t = tagptr_init(compressed_page_t, page); justfound = tagptr_unfold_tags(t); page = tagptr_unfold_ptr(t); /* * preallocated cached pages, which is used to avoid direct reclaim * otherwise, it will go inplace I/O path instead. */ if (page->private == Z_EROFS_PREALLOCATED_PAGE) { WRITE_ONCE(pcl->compressed_pages[nr], page); set_page_private(page, 0); tocache = true; goto out_tocache; } mapping = READ_ONCE(page->mapping); /* * file-backed online pages in plcuster are all locked steady, * therefore it is impossible for `mapping' to be NULL. */ if (mapping && mapping != mc) /* ought to be unmanaged pages */ goto out; /* directly return for shortlived page as well */ if (z_erofs_is_shortlived_page(page)) 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 (oldpage != cmpxchg(&pcl->compressed_pages[nr], oldpage, page)) { erofs_pagepool_add(pagepool, page); cond_resched(); goto repeat; } out_tocache: if (!tocache || add_to_page_cache_lru(page, mc, index + nr, gfp)) { /* turn into temporary page if fails (1 ref) */ set_page_private(page, Z_EROFS_SHORTLIVED_PAGE); goto out; } attach_page_private(page, pcl); /* drop a refcount added by allocpage (then we have 2 refs here) */ put_page(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, struct z_erofs_decompress_frontend *f, struct page **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; z_erofs_next_pcluster_t owned_head = f->clt.owned_head; /* bio is NULL initially, so no need to initialize last_{index,bdev} */ pgoff_t last_index; struct block_device *last_bdev; 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 erofs_map_dev mdev; 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); /* no device id here, thus it will always succeed */ mdev = (struct erofs_map_dev) { .m_pa = blknr_to_addr(pcl->obj.index), }; (void)erofs_map_dev(sb, &mdev); cur = erofs_blknr(mdev.m_pa); end = cur + pcl->pclusterpages; /* 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; page = pickup_page_for_submission(pcl, i++, pagepool, MNGD_MAPPING(sbi), GFP_NOFS); if (!page) continue; if (bio && (cur != last_index + 1 || last_bdev != mdev.m_bdev)) { submit_bio_retry: submit_bio(bio); bio = NULL; } if (!bio) { bio = bio_alloc(GFP_NOIO, BIO_MAX_VECS); bio->bi_end_io = z_erofs_decompressqueue_endio; bio_set_dev(bio, mdev.m_bdev); last_bdev = mdev.m_bdev; bio->bi_iter.bi_sector = (sector_t)cur << LOG_SECTORS_PER_BLOCK; bio->bi_private = bi_private; bio->bi_opf = REQ_OP_READ; if (f->readahead) bio->bi_opf |= REQ_RAHEAD; ++nr_bios; } if (bio_add_page(bio, page, PAGE_SIZE, 0) < 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_decompress_frontend *f, struct page **pagepool, bool force_fg) { struct z_erofs_decompressqueue io[NR_JOBQUEUES]; if (f->clt.owned_head == Z_EROFS_PCLUSTER_TAIL) return; z_erofs_submit_queue(sb, f, 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); } /* * Since partial uptodate is still unimplemented for now, we have to use * approximate readmore strategies as a start. */ static void z_erofs_pcluster_readmore(struct z_erofs_decompress_frontend *f, struct readahead_control *rac, erofs_off_t end, struct page **pagepool, bool backmost) { struct inode *inode = f->inode; struct erofs_map_blocks *map = &f->map; erofs_off_t cur; int err; if (backmost) { map->m_la = end; err = z_erofs_map_blocks_iter(inode, map, EROFS_GET_BLOCKS_READMORE); if (err) return; /* expend ra for the trailing edge if readahead */ if (rac) { loff_t newstart = readahead_pos(rac); cur = round_up(map->m_la + map->m_llen, PAGE_SIZE); readahead_expand(rac, newstart, cur - newstart); return; } end = round_up(end, PAGE_SIZE); } else { end = round_up(map->m_la, PAGE_SIZE); if (!map->m_llen) return; } cur = map->m_la + map->m_llen - 1; while (cur >= end) { pgoff_t index = cur >> PAGE_SHIFT; struct page *page; page = erofs_grab_cache_page_nowait(inode->i_mapping, index); if (!page) goto skip; if (PageUptodate(page)) { unlock_page(page); put_page(page); goto skip; } err = z_erofs_do_read_page(f, page, pagepool); if (err) erofs_err(inode->i_sb, "readmore error at page %lu @ nid %llu", index, EROFS_I(inode)->nid); put_page(page); skip: if (cur < PAGE_SIZE) break; cur = (index << PAGE_SHIFT) - 1; } } 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); struct page *pagepool = NULL; int err; trace_erofs_readpage(page, false); f.headoffset = (erofs_off_t)page->index << PAGE_SHIFT; z_erofs_pcluster_readmore(&f, NULL, f.headoffset + PAGE_SIZE - 1, &pagepool, true); err = z_erofs_do_read_page(&f, page, &pagepool); z_erofs_pcluster_readmore(&f, NULL, 0, &pagepool, false); (void)z_erofs_collector_end(&f.clt); /* if some compressed cluster ready, need submit them anyway */ z_erofs_runqueue(inode->i_sb, &f, &pagepool, true); if (err) erofs_err(inode->i_sb, "failed to read, err [%d]", err); if (f.map.mpage) put_page(f.map.mpage); erofs_release_pages(&pagepool); return err; } static void z_erofs_readahead(struct readahead_control *rac) { struct inode *const inode = rac->mapping->host; struct erofs_sb_info *const sbi = EROFS_I_SB(inode); struct z_erofs_decompress_frontend f = DECOMPRESS_FRONTEND_INIT(inode); struct page *pagepool = NULL, *head = NULL, *page; unsigned int nr_pages; f.readahead = true; f.headoffset = readahead_pos(rac); z_erofs_pcluster_readmore(&f, rac, f.headoffset + readahead_length(rac) - 1, &pagepool, true); nr_pages = readahead_count(rac); trace_erofs_readpages(inode, readahead_index(rac), nr_pages, false); while ((page = readahead_page(rac))) { 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); } z_erofs_pcluster_readmore(&f, rac, 0, &pagepool, false); (void)z_erofs_collector_end(&f.clt); z_erofs_runqueue(inode->i_sb, &f, &pagepool, sbi->opt.readahead_sync_decompress && nr_pages <= sbi->opt.max_sync_decompress_pages); if (f.map.mpage) put_page(f.map.mpage); erofs_release_pages(&pagepool); } const struct address_space_operations z_erofs_aops = { .readpage = z_erofs_readpage, .readahead = z_erofs_readahead, };