diff options
Diffstat (limited to 'fs/erofs/zdata.c')
| -rw-r--r-- | fs/erofs/zdata.c | 1431 |
1 files changed, 1431 insertions, 0 deletions
diff --git a/fs/erofs/zdata.c b/fs/erofs/zdata.c new file mode 100644 index 000000000000..96e34c90f814 --- /dev/null +++ b/fs/erofs/zdata.c @@ -0,0 +1,1431 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2018 HUAWEI, Inc. + * http://www.huawei.com/ + * Created by Gao Xiang <gaoxiang25@huawei.com> + */ +#include "zdata.h" +#include "compress.h" +#include <linux/prefetch.h> + +#include <trace/events/erofs.h> + +/* + * 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 struct z_erofs_collection *cllookup(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; + bool tag; + + grp = erofs_find_workgroup(inode->i_sb, map->m_pa >> PAGE_SHIFT, &tag); + if (!grp) + return NULL; + + 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 ERR_PTR(-EFSCORRUPTED); + } + + cl = z_erofs_primarycollection(pcl); + if (cl->pageofs != (map->m_la & ~PAGE_MASK)) { + DBG_BUGON(1); + erofs_workgroup_put(grp); + return ERR_PTR(-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 ERR_PTR(-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 cl; +} + +static struct z_erofs_collection *clregister(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 ERR_PTR(-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, 0); + if (err) { + mutex_unlock(&cl->lock); + kmem_cache_free(pcluster_cachep, pcl); + return ERR_PTR(-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 cl; +} + +static int z_erofs_collector_begin(struct z_erofs_collector *clt, + struct inode *inode, + struct erofs_map_blocks *map) +{ + struct z_erofs_collection *cl; + + 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: + cl = cllookup(clt, inode, map); + if (!cl) { + cl = clregister(clt, inode, map); + + if (cl == ERR_PTR(-EAGAIN)) + goto repeat; + } + + if (IS_ERR(cl)) + return PTR_ERR(cl); + + z_erofs_pagevec_ctor_init(&clt->vector, Z_EROFS_NR_INLINE_PAGEVECS, + cl->pagevec, 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 inline struct page *__stagingpage_alloc(struct list_head *pagepool, + gfp_t gfp) +{ + struct page *page = erofs_allocpage(pagepool, gfp, true); + + page->mapping = Z_EROFS_MAPPING_STAGING; + return page; +} + +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 __maybe_unused = 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 = (clt->mode >= COLLECT_PRIMARY_HOOKED); + + 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); + + tight &= (clt->mode >= COLLECT_PRIMARY_HOOKED); +hitted: + 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 = + __stagingpage_alloc(pagepool, GFP_NOFS); + + 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_vle_unzip_kickoff(void *ptr, int bios) +{ + tagptr1_t t = tagptr_init(tagptr1_t, ptr); + struct z_erofs_unzip_io *io = tagptr_unfold_ptr(t); + bool background = tagptr_unfold_tags(t); + + if (!background) { + 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 inline void z_erofs_vle_read_endio(struct bio *bio) +{ + struct erofs_sb_info *sbi = NULL; + 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; + bool cachemngd = false; + + DBG_BUGON(PageUptodate(page)); + DBG_BUGON(!page->mapping); + + if (!sbi && !z_erofs_page_is_staging(page)) + sbi = EROFS_SB(page->mapping->host->i_sb); + + /* sbi should already be gotten if the page is managed */ + if (sbi) + cachemngd = erofs_page_is_managed(sbi, page); + + if (err) + SetPageError(page); + else if (cachemngd) + SetPageUptodate(page); + + if (cachemngd) + unlock_page(page); + } + + z_erofs_vle_unzip_kickoff(bio->bi_private, -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_vle_unzip_all(struct super_block *sb, + struct z_erofs_unzip_io *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(sb, pcl, pagepool); + } +} + +static void z_erofs_vle_unzip_wq(struct work_struct *work) +{ + struct z_erofs_unzip_io_sb *iosb = + container_of(work, struct z_erofs_unzip_io_sb, io.u.work); + LIST_HEAD(pagepool); + + DBG_BUGON(iosb->io.head == Z_EROFS_PCLUSTER_TAIL_CLOSED); + z_erofs_vle_unzip_all(iosb->sb, &iosb->io, &pagepool); + + put_pages_list(&pagepool); + kvfree(iosb); +} + +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) +{ + /* determined at compile time to avoid too many #ifdefs */ + const bool nocache = __builtin_constant_p(mc) ? !mc : false; + 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 (!nocache && 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); + + /* + * if managed cache is disabled, it's no way to + * get such a cached-like page. + */ + if (nocache) { + /* if managed cache is disabled, it is impossible `justfound' */ + DBG_BUGON(justfound); + + /* and it should be locked, not uptodate, and not truncated */ + DBG_BUGON(!PageLocked(page)); + DBG_BUGON(PageUptodate(page)); + DBG_BUGON(!mapping); + goto out; + } + + /* + * 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 = __stagingpage_alloc(pagepool, gfp); + if (oldpage != cmpxchg(&pcl->compressed_pages[nr], oldpage, page)) { + list_add(&page->lru, pagepool); + cpu_relax(); + goto repeat; + } + if (nocache || !tocache) + goto out; + if (add_to_page_cache_lru(page, mc, index + nr, gfp)) { + page->mapping = Z_EROFS_MAPPING_STAGING; + goto out; + } + + set_page_private(page, (unsigned long)pcl); + SetPagePrivate(page); +out: /* the only exit (for tracing and debugging) */ + return page; +} + +static struct z_erofs_unzip_io *jobqueue_init(struct super_block *sb, + struct z_erofs_unzip_io *io, + bool foreground) +{ + struct z_erofs_unzip_io_sb *iosb; + + if (foreground) { + /* waitqueue available for foreground io */ + DBG_BUGON(!io); + + init_waitqueue_head(&io->u.wait); + atomic_set(&io->pending_bios, 0); + goto out; + } + + iosb = kvzalloc(sizeof(*iosb), GFP_KERNEL | __GFP_NOFAIL); + DBG_BUGON(!iosb); + + /* initialize fields in the allocated descriptor */ + io = &iosb->io; + iosb->sb = sb; + INIT_WORK(&io->u.work, z_erofs_vle_unzip_wq); +out: + io->head = Z_EROFS_PCLUSTER_TAIL_CLOSED; + return io; +} + +/* define decompression jobqueue types */ +enum { + JQ_BYPASS, + JQ_SUBMIT, + NR_JOBQUEUES, +}; + +static void *jobqueueset_init(struct super_block *sb, + z_erofs_next_pcluster_t qtail[], + struct z_erofs_unzip_io *q[], + struct z_erofs_unzip_io *fgq, + bool forcefg) +{ + /* + * 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, true); + qtail[JQ_BYPASS] = &q[JQ_BYPASS]->head; + + q[JQ_SUBMIT] = jobqueue_init(sb, fgq + JQ_SUBMIT, forcefg); + qtail[JQ_SUBMIT] = &q[JQ_SUBMIT]->head; + + return tagptr_cast_ptr(tagptr_fold(tagptr1_t, q[JQ_SUBMIT], !forcefg)); +} + +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 bool postsubmit_is_all_bypassed(struct z_erofs_unzip_io *q[], + unsigned int nr_bios, + bool force_fg) +{ + /* + * 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) + return false; + + kvfree(container_of(q[JQ_SUBMIT], struct z_erofs_unzip_io_sb, io)); + return true; +} + +static bool z_erofs_vle_submit_all(struct super_block *sb, + z_erofs_next_pcluster_t owned_head, + struct list_head *pagepool, + struct z_erofs_unzip_io *fgq, + bool force_fg) +{ + struct erofs_sb_info *const sbi __maybe_unused = EROFS_SB(sb); + z_erofs_next_pcluster_t qtail[NR_JOBQUEUES]; + struct z_erofs_unzip_io *q[NR_JOBQUEUES]; + struct bio *bio; + void *bi_private; + /* since bio will be NULL, no need to initialize last_index */ + pgoff_t uninitialized_var(last_index); + bool force_submit = false; + unsigned int nr_bios; + + if (owned_head == Z_EROFS_PCLUSTER_TAIL) + return false; + + force_submit = false; + bio = NULL; + nr_bios = 0; + bi_private = jobqueueset_init(sb, qtail, q, fgq, force_fg); + + /* by default, all need io submission */ + q[JQ_SUBMIT]->head = owned_head; + + do { + struct z_erofs_pcluster *pcl; + unsigned int clusterpages; + pgoff_t first_index; + struct page *page; + unsigned int i = 0, bypass = 0; + int err; + + /* 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); + + clusterpages = BIT(pcl->clusterbits); + + /* close the main owned chain at first */ + owned_head = cmpxchg(&pcl->next, Z_EROFS_PCLUSTER_TAIL, + Z_EROFS_PCLUSTER_TAIL_CLOSED); + + first_index = pcl->obj.index; + force_submit |= (first_index != last_index + 1); + +repeat: + page = pickup_page_for_submission(pcl, i, pagepool, + MNGD_MAPPING(sbi), + GFP_NOFS); + if (!page) { + force_submit = true; + ++bypass; + goto skippage; + } + + if (bio && force_submit) { +submit_bio_retry: + submit_bio(bio); + bio = NULL; + } + + if (!bio) { + bio = bio_alloc(GFP_NOIO, BIO_MAX_PAGES); + + bio->bi_end_io = z_erofs_vle_read_endio; + bio_set_dev(bio, sb->s_bdev); + bio->bi_iter.bi_sector = (sector_t)(first_index + i) << + 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; + + force_submit = false; + last_index = first_index + i; +skippage: + if (++i < clusterpages) + goto repeat; + + if (bypass < clusterpages) + 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); + + if (postsubmit_is_all_bypassed(q, nr_bios, force_fg)) + return true; + + z_erofs_vle_unzip_kickoff(bi_private, nr_bios); + return true; +} + +static void z_erofs_submit_and_unzip(struct super_block *sb, + struct z_erofs_collector *clt, + struct list_head *pagepool, + bool force_fg) +{ + struct z_erofs_unzip_io io[NR_JOBQUEUES]; + + if (!z_erofs_vle_submit_all(sb, clt->owned_head, + pagepool, io, force_fg)) + return; + + /* decompress no I/O pclusters immediately */ + z_erofs_vle_unzip_all(sb, &io[JQ_BYPASS], pagepool); + + if (!force_fg) + return; + + /* wait until all bios are completed */ + wait_event(io[JQ_SUBMIT].u.wait, + !atomic_read(&io[JQ_SUBMIT].pending_bios)); + + /* let's synchronous decompression */ + z_erofs_vle_unzip_all(sb, &io[JQ_SUBMIT], pagepool); +} + +static int z_erofs_vle_normalaccess_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_submit_and_unzip(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_vle_normalaccess_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_submit_and_unzip(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_vle_normalaccess_aops = { + .readpage = z_erofs_vle_normalaccess_readpage, + .readpages = z_erofs_vle_normalaccess_readpages, +}; + |