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- // SPDX-License-Identifier: GPL-2.0-only
- /*
- * Copyright (C) 2018 HUAWEI, Inc.
- * https://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>
- /*
- * 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);
- }
- /*
- * 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) */
- /*
- * 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 list_head *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 DELAYEDALLOC:
- t = tagptr_init(compressed_page_t,
- PAGE_UNALLOCATED);
- break;
- 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) {
- set_page_private(newpage, 0);
- list_add(&newpage->lru, pagepool);
- }
- }
- /*
- * 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);
- struct address_space *const mapping = MNGD_MAPPING(sbi);
- 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 (page->mapping != mapping)
- 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 address_space *mapping,
- 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 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 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;
- 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->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;
- /* 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->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;
- /* 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 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->ctx.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 staging 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->ctx.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 list_head *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 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);
- /*
- * 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)) {
- list_add(&page->lru, pagepool);
- 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 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;
- z_erofs_next_pcluster_t owned_head = f->clt.owned_head;
- /* since bio will be NULL, no need to initialize last_index */
- pgoff_t 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 + 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) {
- 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;
- 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 list_head *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);
- }
- 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, &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 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);
- unsigned int nr_pages = readahead_count(rac);
- bool sync = (sbi->ctx.readahead_sync_decompress &&
- nr_pages <= sbi->ctx.max_sync_decompress_pages);
- struct z_erofs_decompress_frontend f = DECOMPRESS_FRONTEND_INIT(inode);
- struct page *page, *head = NULL;
- LIST_HEAD(pagepool);
- trace_erofs_readpages(inode, readahead_index(rac), nr_pages, false);
- f.readahead = true;
- f.headoffset = readahead_pos(rac);
- while ((page = readahead_page(rac))) {
- prefetchw(&page->flags);
- /*
- * 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);
- 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, &pagepool, sync);
- if (f.map.mpage)
- put_page(f.map.mpage);
- /* clean up the remaining free pages */
- put_pages_list(&pagepool);
- }
- const struct address_space_operations z_erofs_aops = {
- .readpage = z_erofs_readpage,
- .readahead = z_erofs_readahead,
- };
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