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zdata.c
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// 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)
{
unsigned int pclusterpages = z_erofs_pclusterpages(pcl);
int i;
for (i = 0; i < ARRAY_SIZE(pcluster_pool); ++i) {
struct z_erofs_pcluster_slab *pcs = pcluster_pool + i;
if (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_decompress_frontend {
struct inode *const inode;
struct erofs_map_blocks map;
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;
bool readahead;
/* used for applying cache strategy on the fly */
bool backmost;
erofs_off_t headoffset;
};
#define DECOMPRESS_FRONTEND_INIT(__i) { \
.inode = __i, .owned_head = Z_EROFS_PCLUSTER_TAIL, \
.mode = COLLECT_PRIMARY_FOLLOWED }
static struct page *z_pagemap_global[Z_EROFS_VMAP_GLOBAL_PAGES];
static DEFINE_MUTEX(z_pagemap_global_lock);
static void z_erofs_bind_cache(struct z_erofs_decompress_frontend *fe,
enum z_erofs_cache_alloctype type,
struct page **pagepool)
{
struct address_space *mc = MNGD_MAPPING(EROFS_I_SB(fe->inode));
struct z_erofs_pcluster *pcl = fe->pcl;
bool standalone = true;
/*
* optimistic allocation without direct reclaim since inplace I/O
* can be used if low memory otherwise.
*/
gfp_t gfp = (mapping_gfp_mask(mc) & ~__GFP_DIRECT_RECLAIM) |
__GFP_NOMEMALLOC | __GFP_NORETRY | __GFP_NOWARN;
struct page **pages;
pgoff_t index;
if (fe->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)
fe->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;
DBG_BUGON(z_erofs_is_inline_pcluster(pcl));
/*
* 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;
DBG_BUGON(z_erofs_is_inline_pcluster(pcl));
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_decompress_frontend *fe,
struct page *page)
{
struct z_erofs_pcluster *const pcl = fe->pcl;
while (fe->icpage_ptr > pcl->compressed_pages)
if (!cmpxchg(--fe->icpage_ptr, NULL, page))
return true;
return false;
}
/* callers must be with collection lock held */
static int z_erofs_attach_page(struct z_erofs_decompress_frontend *fe,
struct page *page, enum z_erofs_page_type type,
bool pvec_safereuse)
{
int ret;
/* give priority for inplaceio */
if (fe->mode >= COLLECT_PRIMARY &&
type == Z_EROFS_PAGE_TYPE_EXCLUSIVE &&
z_erofs_try_inplace_io(fe, page))
return 0;
ret = z_erofs_pagevec_enqueue(&fe->vector, page, type,
pvec_safereuse);
fe->cl->vcnt += (unsigned int)ret;
return ret ? 0 : -EAGAIN;
}
static void z_erofs_try_to_claim_pcluster(struct z_erofs_decompress_frontend *f)
{
struct z_erofs_pcluster *pcl = f->pcl;
z_erofs_next_pcluster_t *owned_head = &f->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. */
f->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;
f->mode = COLLECT_PRIMARY_HOOKED;
f->tailpcl = NULL;
return;
}
/* type 3, it belongs to a chain, but it isn't the end of the chain */
f->mode = COLLECT_PRIMARY;
}
static int z_erofs_lookup_collection(struct z_erofs_decompress_frontend *fe,
struct inode *inode,
struct erofs_map_blocks *map)
{
struct z_erofs_pcluster *pcl = fe->pcl;
struct z_erofs_collection *cl;
unsigned int length;
/* to avoid unexpected loop formed by corrupted images */
if (fe->owned_head == &pcl->next || pcl == fe->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 (fe->owned_head == Z_EROFS_PCLUSTER_TAIL)
fe->tailpcl = pcl;
z_erofs_try_to_claim_pcluster(fe);
fe->cl = cl;
return 0;
}
static int z_erofs_register_collection(struct z_erofs_decompress_frontend *fe,
struct inode *inode,
struct erofs_map_blocks *map)
{
bool ztailpacking = map->m_flags & EROFS_MAP_META;
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(ztailpacking ? 1 :
map->m_plen >> PAGE_SHIFT);
if (IS_ERR(pcl))
return PTR_ERR(pcl);
atomic_set(&pcl->obj.refcount, 1);
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 = fe->owned_head;
fe->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));
if (ztailpacking) {
pcl->obj.index = 0; /* which indicates ztailpacking */
pcl->pageofs_in = erofs_blkoff(map->m_pa);
pcl->tailpacking_size = map->m_plen;
} else {
pcl->obj.index = map->m_pa >> PAGE_SHIFT;
grp = erofs_insert_workgroup(inode->i_sb, &pcl->obj);
if (IS_ERR(grp)) {
err = PTR_ERR(grp);
goto err_out;
}
if (grp != &pcl->obj) {
fe->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 (fe->owned_head == Z_EROFS_PCLUSTER_TAIL)
fe->tailpcl = pcl;
fe->owned_head = &pcl->next;
fe->pcl = pcl;
fe->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_decompress_frontend *fe,
struct inode *inode,
struct erofs_map_blocks *map)
{
struct erofs_workgroup *grp;
int ret;
DBG_BUGON(fe->cl);
/* must be Z_EROFS_PCLUSTER_TAIL or pointed to previous collection */
DBG_BUGON(fe->owned_head == Z_EROFS_PCLUSTER_NIL);
DBG_BUGON(fe->owned_head == Z_EROFS_PCLUSTER_TAIL_CLOSED);
if (map->m_flags & EROFS_MAP_META) {
if ((map->m_pa & ~PAGE_MASK) + map->m_plen > PAGE_SIZE) {
DBG_BUGON(1);
return -EFSCORRUPTED;
}
goto tailpacking;
}
grp = erofs_find_workgroup(inode->i_sb, map->m_pa >> PAGE_SHIFT);
if (grp) {
fe->pcl = container_of(grp, struct z_erofs_pcluster, obj);
} else {
tailpacking:
ret = z_erofs_register_collection(fe, inode, map);
if (!ret)
goto out;
if (ret != -EEXIST)
return ret;
}
ret = z_erofs_lookup_collection(fe, inode, map);
if (ret) {
erofs_workgroup_put(&fe->pcl->obj);
return ret;
}
out:
z_erofs_pagevec_ctor_init(&fe->vector, Z_EROFS_NR_INLINE_PAGEVECS,
fe->cl->pagevec, fe->cl->vcnt);
/* since file-backed online pages are traversed in reverse order */
fe->icpage_ptr = fe->pcl->compressed_pages +
z_erofs_pclusterpages(fe->pcl);
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_decompress_frontend *fe)
{
struct z_erofs_collection *cl = fe->cl;
if (!cl)
return false;
z_erofs_pagevec_ctor_exit(&fe->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 (fe->mode < COLLECT_PRIMARY_FOLLOWED_NOINPLACE)
z_erofs_collection_put(cl);
fe->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;
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 (!fe->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(fe))
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(fe, inode, map);
if (err)
goto err_out;
if (z_erofs_is_inline_pcluster(fe->pcl)) {
void *mp;
mp = erofs_read_metabuf(&fe->map.buf, inode->i_sb,
erofs_blknr(map->m_pa), EROFS_NO_KMAP);
if (IS_ERR(mp)) {
err = PTR_ERR(mp);
erofs_err(inode->i_sb,
"failed to get inline page, err %d", err);
goto err_out;
}
get_page(fe->map.buf.page);
WRITE_ONCE(fe->pcl->compressed_pages[0], fe->map.buf.page);
fe->mode = COLLECT_PRIMARY_FOLLOWED_NOINPLACE;
} else {
/* bind cache first when cached decompression is preferred */
if (should_alloc_managed_pages(fe, sbi->opt.cache_strategy,
map->m_la))
cache_strategy = TRYALLOC;
else
cache_strategy = DONTALLOC;
z_erofs_bind_cache(fe, 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 &= (fe->mode >= COLLECT_PRIMARY_HOOKED &&
fe->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 &= (fe->mode >= COLLECT_PRIMARY_FOLLOWED);
retry:
err = z_erofs_attach_page(fe, page, page_type,
fe->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(fe, 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 */
fe->cl->nr_pages = max_t(pgoff_t, fe->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 bool z_erofs_get_sync_decompress_policy(struct erofs_sb_info *sbi,
unsigned int readahead_pages)
{
/* auto: enable for readpage, disable for readahead */
if ((sbi->opt.sync_decompress == EROFS_SYNC_DECOMPRESS_AUTO) &&
!readahead_pages)
return true;
if ((sbi->opt.sync_decompress == EROFS_SYNC_DECOMPRESS_FORCE_ON) &&
(readahead_pages <= sbi->opt.max_sync_decompress_pages))
return true;
return false;
}
static bool z_erofs_page_is_invalidated(struct page *page)
{
return !page->mapping && !z_erofs_is_shortlived_page(page);
}
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);
unsigned int pclusterpages = z_erofs_pclusterpages(pcl);
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 < pclusterpages; ++i) {
unsigned int pagenr;
page = compressed_pages[i];
/* all compressed pages ought to be valid */
DBG_BUGON(!page);
if (z_erofs_is_inline_pcluster(pcl)) {
if (!PageUptodate(page))
err = -EIO;
continue;
}
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;
}
if (z_erofs_is_inline_pcluster(pcl))
inputsize = pcl->tailpacking_size;
else
inputsize = pclusterpages * PAGE_SIZE;
err = z_erofs_decompress(&(struct z_erofs_decompress_req) {
.sb = sb,
.in = compressed_pages,
.out = pages,
.pageofs_in = pcl->pageofs_in,
.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 actual file pages */
if (z_erofs_is_inline_pcluster(pcl)) {
page = compressed_pages[0];
WRITE_ONCE(compressed_pages[0], NULL);
put_page(page);
} else {
for (i = 0; i < 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 */