blob: c7511b4317763b6d6a2152d48f5827eec16439db [file] [log] [blame]
// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2018 HUAWEI, Inc.
* https://www.huawei.com/
* Copyright (C) 2022 Alibaba Cloud
*/
#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)
};
struct z_erofs_bvec_iter {
struct page *bvpage;
struct z_erofs_bvset *bvset;
unsigned int nr, cur;
};
static struct page *z_erofs_bvec_iter_end(struct z_erofs_bvec_iter *iter)
{
if (iter->bvpage)
kunmap_local(iter->bvset);
return iter->bvpage;
}
static struct page *z_erofs_bvset_flip(struct z_erofs_bvec_iter *iter)
{
unsigned long base = (unsigned long)((struct z_erofs_bvset *)0)->bvec;
/* have to access nextpage in advance, otherwise it will be unmapped */
struct page *nextpage = iter->bvset->nextpage;
struct page *oldpage;
DBG_BUGON(!nextpage);
oldpage = z_erofs_bvec_iter_end(iter);
iter->bvpage = nextpage;
iter->bvset = kmap_local_page(nextpage);
iter->nr = (PAGE_SIZE - base) / sizeof(struct z_erofs_bvec);
iter->cur = 0;
return oldpage;
}
static void z_erofs_bvec_iter_begin(struct z_erofs_bvec_iter *iter,
struct z_erofs_bvset_inline *bvset,
unsigned int bootstrap_nr,
unsigned int cur)
{
*iter = (struct z_erofs_bvec_iter) {
.nr = bootstrap_nr,
.bvset = (struct z_erofs_bvset *)bvset,
};
while (cur > iter->nr) {
cur -= iter->nr;
z_erofs_bvset_flip(iter);
}
iter->cur = cur;
}
static int z_erofs_bvec_enqueue(struct z_erofs_bvec_iter *iter,
struct z_erofs_bvec *bvec,
struct page **candidate_bvpage)
{
if (iter->cur == iter->nr) {
if (!*candidate_bvpage)
return -EAGAIN;
DBG_BUGON(iter->bvset->nextpage);
iter->bvset->nextpage = *candidate_bvpage;
z_erofs_bvset_flip(iter);
iter->bvset->nextpage = NULL;
*candidate_bvpage = NULL;
}
iter->bvset->bvec[iter->cur++] = *bvec;
return 0;
}
static void z_erofs_bvec_dequeue(struct z_erofs_bvec_iter *iter,
struct z_erofs_bvec *bvec,
struct page **old_bvpage)
{
if (iter->cur == iter->nr)
*old_bvpage = z_erofs_bvset_flip(iter);
else
*old_bvpage = NULL;
*bvec = iter->bvset->bvec[iter->cur++];
}
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_bvecs, 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_pclustermode {
Z_EROFS_PCLUSTER_INFLIGHT,
/*
* The current pclusters was the tail of an exist chain, in addition
* that the previous processed chained pclusters are all decided to
* be hooked up to it.
* A new chain will be created for the remaining pclusters which are
* not processed yet, so different from Z_EROFS_PCLUSTER_FOLLOWED,
* the next pcluster cannot reuse the whole page safely for inplace I/O
* in the following scenario:
* ________________________________________________________________
* | tail (partial) page | head (partial) page |
* | (belongs to the next pcl) | (belongs to the current pcl) |
* |_______PCLUSTER_FOLLOWED______|________PCLUSTER_HOOKED__________|
*/
Z_EROFS_PCLUSTER_HOOKED,
/*
* a weak form of Z_EROFS_PCLUSTER_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
* bvpage) since it can be directly decoded without I/O submission.
*/
Z_EROFS_PCLUSTER_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) |
* | PCLUSTER_FOLLOWED or | |
* |_____PCLUSTER_HOOKED__|___________PCLUSTER_FOLLOWED____________|
*
* [ (*) the above page can be used as inplace I/O. ]
*/
Z_EROFS_PCLUSTER_FOLLOWED,
};
struct z_erofs_decompress_frontend {
struct inode *const inode;
struct erofs_map_blocks map;
struct z_erofs_bvec_iter biter;
struct page *candidate_bvpage;
struct z_erofs_pcluster *pcl, *tailpcl;
z_erofs_next_pcluster_t owned_head;
enum z_erofs_pclustermode mode;
bool readahead;
/* used for applying cache strategy on the fly */
bool backmost;
erofs_off_t headoffset;
/* a pointer used to pick up inplace I/O pages */
unsigned int icur;
};
#define DECOMPRESS_FRONTEND_INIT(__i) { \
.inode = __i, .owned_head = Z_EROFS_PCLUSTER_TAIL, \
.mode = Z_EROFS_PCLUSTER_FOLLOWED, .backmost = true }
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;
unsigned int i;
if (fe->mode < Z_EROFS_PCLUSTER_FOLLOWED)
return;
for (i = 0; i < pcl->pclusterpages; ++i) {
struct page *page;
compressed_page_t t;
struct page *newpage = NULL;
/* the compressed page was loaded before */
if (READ_ONCE(pcl->compressed_bvecs[i].page))
continue;
page = find_get_page(mc, pcl->obj.index + i);
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(&pcl->compressed_bvecs[i].page, 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 = Z_EROFS_PCLUSTER_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_bvecs[i].page;
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_bvecs[i].page, 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, i;
if (!erofs_workgroup_try_to_freeze(&pcl->obj, 1))
return 0;
ret = 0;
DBG_BUGON(z_erofs_is_inline_pcluster(pcl));
for (i = 0; i < pcl->pclusterpages; ++i) {
if (pcl->compressed_bvecs[i].page == page) {
WRITE_ONCE(pcl->compressed_bvecs[i].page, NULL);
ret = 1;
break;
}
}
erofs_workgroup_unfreeze(&pcl->obj, 1);
if (ret)
detach_page_private(page);
return ret;
}
static bool z_erofs_try_inplace_io(struct z_erofs_decompress_frontend *fe,
struct z_erofs_bvec *bvec)
{
struct z_erofs_pcluster *const pcl = fe->pcl;
while (fe->icur > 0) {
if (!cmpxchg(&pcl->compressed_bvecs[--fe->icur].page,
NULL, bvec->page)) {
pcl->compressed_bvecs[fe->icur] = *bvec;
return true;
}
}
return false;
}
/* callers must be with pcluster lock held */
static int z_erofs_attach_page(struct z_erofs_decompress_frontend *fe,
struct z_erofs_bvec *bvec, bool exclusive)
{
int ret;
if (exclusive) {
/* give priority for inplaceio to use file pages first */
if (z_erofs_try_inplace_io(fe, bvec))
return 0;
/* otherwise, check if it can be used as a bvpage */
if (fe->mode >= Z_EROFS_PCLUSTER_FOLLOWED &&
!fe->candidate_bvpage)
fe->candidate_bvpage = bvec->page;
}
ret = z_erofs_bvec_enqueue(&fe->biter, bvec, &fe->candidate_bvpage);
fe->pcl->vcnt += (ret >= 0);
return ret;
}
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 = Z_EROFS_PCLUSTER_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 (*owned_head != &pcl->next && pcl != f->tailpcl &&
cmpxchg(&pcl->next, Z_EROFS_PCLUSTER_TAIL,
*owned_head) == Z_EROFS_PCLUSTER_TAIL) {
*owned_head = Z_EROFS_PCLUSTER_TAIL;
f->mode = Z_EROFS_PCLUSTER_HOOKED;
f->tailpcl = NULL;
return;
}
/* type 3, it belongs to a chain, but it isn't the end of the chain */
f->mode = Z_EROFS_PCLUSTER_INFLIGHT;
}
static int z_erofs_register_pcluster(struct z_erofs_decompress_frontend *fe)
{
struct erofs_map_blocks *map = &fe->map;
bool ztailpacking = map->m_flags & EROFS_MAP_META;
struct z_erofs_pcluster *pcl;
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 = 0;
pcl->partial = true;
/* new pclusters should be claimed as type 1, primary and followed */
pcl->next = fe->owned_head;
pcl->pageofs_out = map->m_la & ~PAGE_MASK;
fe->mode = Z_EROFS_PCLUSTER_FOLLOWED;
/*
* lock all primary followed works before visible to others
* and mutex_trylock *never* fails for a new pcluster.
*/
mutex_init(&pcl->lock);
DBG_BUGON(!mutex_trylock(&pcl->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(fe->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;
return 0;
err_out:
mutex_unlock(&pcl->lock);
z_erofs_free_pcluster(pcl);
return err;
}
static int z_erofs_collector_begin(struct z_erofs_decompress_frontend *fe)
{
struct erofs_map_blocks *map = &fe->map;
struct erofs_workgroup *grp = NULL;
int ret;
DBG_BUGON(fe->pcl);
/* must be Z_EROFS_PCLUSTER_TAIL or pointed to previous pcluster */
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)) {
grp = erofs_find_workgroup(fe->inode->i_sb,
map->m_pa >> PAGE_SHIFT);
} else if ((map->m_pa & ~PAGE_MASK) + map->m_plen > PAGE_SIZE) {
DBG_BUGON(1);
return -EFSCORRUPTED;
}
if (grp) {
fe->pcl = container_of(grp, struct z_erofs_pcluster, obj);
ret = -EEXIST;
} else {
ret = z_erofs_register_pcluster(fe);
}
if (ret == -EEXIST) {
mutex_lock(&fe->pcl->lock);
/* used to check tail merging loop due to corrupted images */
if (fe->owned_head == Z_EROFS_PCLUSTER_TAIL)
fe->tailpcl = fe->pcl;
z_erofs_try_to_claim_pcluster(fe);
} else if (ret) {
return ret;
}
z_erofs_bvec_iter_begin(&fe->biter, &fe->pcl->bvset,
Z_EROFS_INLINE_BVECS, fe->pcl->vcnt);
/* since file-backed online pages are traversed in reverse order */
fe->icur = 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)
{
z_erofs_free_pcluster(container_of(head,
struct z_erofs_pcluster, rcu));
}
void erofs_workgroup_free_rcu(struct erofs_workgroup *grp)
{
struct z_erofs_pcluster *const pcl =
container_of(grp, struct z_erofs_pcluster, obj);
call_rcu(&pcl->rcu, z_erofs_rcu_callback);
}
static bool z_erofs_collector_end(struct z_erofs_decompress_frontend *fe)
{
struct z_erofs_pcluster *pcl = fe->pcl;
if (!pcl)
return false;
z_erofs_bvec_iter_end(&fe->biter);
mutex_unlock(&pcl->lock);
if (fe->candidate_bvpage) {
DBG_BUGON(z_erofs_is_shortlived_page(fe->candidate_bvpage));
fe->candidate_bvpage = NULL;
}
/*
* if all pending pages are added, don't hold its reference
* any longer if the pcluster isn't hosted by ourselves.
*/
if (fe->mode < Z_EROFS_PCLUSTER_FOLLOWED_NOINPLACE)
erofs_workgroup_put(&pcl->obj);
fe->pcl = 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, exclusive;
enum z_erofs_cache_alloctype cache_strategy;
unsigned int cur, end, spiltted;
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;
if (offset + cur < map->m_la ||
offset + cur >= map->m_la + map->m_llen) {
erofs_dbg("out-of-range map @ pos %llu", 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 out;
} else {
if (fe->pcl)
goto hitted;
/* didn't get a valid pcluster previously (very rare) */
}
if (!(map->m_flags & EROFS_MAP_MAPPED))
goto hitted;
err = z_erofs_collector_begin(fe);
if (err)
goto 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 out;
}
get_page(fe->map.buf.page);
WRITE_ONCE(fe->pcl->compressed_bvecs[0].page,
fe->map.buf.page);
fe->mode = Z_EROFS_PCLUSTER_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 bvpage (should be processed in a strict order.)
*/
tight &= (fe->mode >= Z_EROFS_PCLUSTER_HOOKED &&
fe->mode != Z_EROFS_PCLUSTER_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;
}
exclusive = (!cur && (!spiltted || tight));
if (cur)
tight &= (fe->mode >= Z_EROFS_PCLUSTER_FOLLOWED);
retry:
err = z_erofs_attach_page(fe, &((struct z_erofs_bvec) {
.page = page,
.offset = offset - map->m_la,
.end = end,
}), exclusive);
/* should allocate an additional short-lived page for bvset */
if (err == -EAGAIN && !fe->candidate_bvpage) {
fe->candidate_bvpage = alloc_page(GFP_NOFS | __GFP_NOFAIL);
set_page_private(fe->candidate_bvpage,
Z_EROFS_SHORTLIVED_PAGE);
goto retry;
}
if (err) {
DBG_BUGON(err == -EAGAIN && fe->candidate_bvpage);
goto out;
}
z_erofs_onlinepage_split(page);
/* bump up the number of spiltted parts of a page */
++spiltted;
if (fe->pcl->pageofs_out != (map->m_la & ~PAGE_MASK))
fe->pcl->multibases = true;
if (fe->pcl->length < offset + end - map->m_la) {
fe->pcl->length = offset + end - map->m_la;
fe->pcl->pageofs_out = map->m_la & ~PAGE_MASK;
}
if ((map->m_flags & EROFS_MAP_FULL_MAPPED) &&
fe->pcl->length == map->m_llen)
fe->pcl->partial = false;
next_part:
/* shorten the remaining extent to update progress */
map->m_llen = offset + cur - map->m_la;
map->m_flags &= ~EROFS_MAP_FULL_MAPPED;
end = cur;
if (end > 0)
goto repeat;
out:
if (err)
z_erofs_page_mark_eio(page);
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;
}
static bool z_erofs_get_sync_decompress_policy(struct erofs_sb_info *sbi,
unsigned int readahead_pages)
{
/* auto: enable for read_folio, 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);
}
struct z_erofs_decompress_backend {
struct page *onstack_pages[Z_EROFS_ONSTACK_PAGES];
struct super_block *sb;
struct z_erofs_pcluster *pcl;
/* pages with the longest decompressed length for deduplication */
struct page **decompressed_pages;
/* pages to keep the compressed data */
struct page **compressed_pages;
struct list_head decompressed_secondary_bvecs;
struct page **pagepool;
unsigned int onstack_used, nr_pages;
};
struct z_erofs_bvec_item {
struct z_erofs_bvec bvec;
struct list_head list;
};
static void z_erofs_do_decompressed_bvec(struct z_erofs_decompress_backend *be,
struct z_erofs_bvec *bvec)
{
struct z_erofs_bvec_item *item;
if (!((bvec->offset + be->pcl->pageofs_out) & ~PAGE_MASK)) {
unsigned int pgnr;
pgnr = (bvec->offset + be->pcl->pageofs_out) >> PAGE_SHIFT;
DBG_BUGON(pgnr >= be->nr_pages);
if (!be->decompressed_pages[pgnr]) {
be->decompressed_pages[pgnr] = bvec->page;
return;
}
}
/* (cold path) one pcluster is requested multiple times */
item = kmalloc(sizeof(*item), GFP_KERNEL | __GFP_NOFAIL);
item->bvec = *bvec;
list_add(&item->list, &be->decompressed_secondary_bvecs);
}
static void z_erofs_fill_other_copies(struct z_erofs_decompress_backend *be,
int err)
{
unsigned int off0 = be->pcl->pageofs_out;
struct list_head *p, *n;
list_for_each_safe(p, n, &be->decompressed_secondary_bvecs) {
struct z_erofs_bvec_item *bvi;
unsigned int end, cur;
void *dst, *src;
bvi = container_of(p, struct z_erofs_bvec_item, list);
cur = bvi->bvec.offset < 0 ? -bvi->bvec.offset : 0;
end = min_t(unsigned int, be->pcl->length - bvi->bvec.offset,
bvi->bvec.end);
dst = kmap_local_page(bvi->bvec.page);
while (cur < end) {
unsigned int pgnr, scur, len;
pgnr = (bvi->bvec.offset + cur + off0) >> PAGE_SHIFT;
DBG_BUGON(pgnr >= be->nr_pages);
scur = bvi->bvec.offset + cur -
((pgnr << PAGE_SHIFT) - off0);
len = min_t(unsigned int, end - cur, PAGE_SIZE - scur);
if (!be->decompressed_pages[pgnr]) {
err = -EFSCORRUPTED;
cur += len;
continue;
}
src = kmap_local_page(be->decompressed_pages[pgnr]);
memcpy(dst + cur, src + scur, len);
kunmap_local(src);
cur += len;
}
kunmap_local(dst);
if (err)
z_erofs_page_mark_eio(bvi->bvec.page);
z_erofs_onlinepage_endio(bvi->bvec.page);
list_del(p);
kfree(bvi);
}
}
static void z_erofs_parse_out_bvecs(struct z_erofs_decompress_backend *be)
{
struct z_erofs_pcluster *pcl = be->pcl;
struct z_erofs_bvec_iter biter;
struct page *old_bvpage;
int i;
z_erofs_bvec_iter_begin(&biter, &pcl->bvset, Z_EROFS_INLINE_BVECS, 0);
for (i = 0; i < pcl->vcnt; ++i) {
struct z_erofs_bvec bvec;
z_erofs_bvec_dequeue(&biter, &bvec, &old_bvpage);
if (old_bvpage)
z_erofs_put_shortlivedpage(be->pagepool, old_bvpage);
DBG_BUGON(z_erofs_page_is_invalidated(bvec.page));
z_erofs_do_decompressed_bvec(be, &bvec);
}
old_bvpage = z_erofs_bvec_iter_end(&biter);
if (old_bvpage)
z_erofs_put_shortlivedpage(be->pagepool, old_bvpage);
}
static int z_erofs_parse_in_bvecs(struct z_erofs_decompress_backend *be,
bool *overlapped)
{
struct z_erofs_pcluster *pcl = be->pcl;
unsigned int pclusterpages = z_erofs_pclusterpages(pcl);
int i, err = 0;
*overlapped = false;
for (i = 0; i < pclusterpages; ++i) {
struct z_erofs_bvec *bvec = &pcl->compressed_bvecs[i];
struct page *page = bvec->page;
/* compressed pages ought to be present before decompressing */
if (!page) {
DBG_BUGON(1);
continue;
}
be->compressed_pages[i] = 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(EROFS_SB(be->sb), page)) {
if (!PageUptodate(page))
err = -EIO;
continue;
}
z_erofs_do_decompressed_bvec(be, bvec);
*overlapped = true;
}
}
if (err)
return err;
return 0;
}
static int z_erofs_decompress_pcluster(struct z_erofs_decompress_backend *be,
int err)
{
struct erofs_sb_info *const sbi = EROFS_SB(be->sb);
struct z_erofs_pcluster *pcl = be->pcl;
unsigned int pclusterpages = z_erofs_pclusterpages(pcl);
unsigned int i, inputsize;
int err2;
struct page *page;
bool overlapped;
mutex_lock(&pcl->lock);
be->nr_pages = PAGE_ALIGN(pcl->length + pcl->pageofs_out) >> PAGE_SHIFT;
/* allocate (de)compressed page arrays if cannot be kept on stack */
be->decompressed_pages = NULL;
be->compressed_pages = NULL;
be->onstack_used = 0;
if (be->nr_pages <= Z_EROFS_ONSTACK_PAGES) {
be->decompressed_pages = be->onstack_pages;
be->onstack_used = be->nr_pages;
memset(be->decompressed_pages, 0,
sizeof(struct page *) * be->nr_pages);
}
if (pclusterpages + be->onstack_used <= Z_EROFS_ONSTACK_PAGES)
be->compressed_pages = be->onstack_pages + be->onstack_used;
if (!be->decompressed_pages)
be->decompressed_pages =
kvcalloc(be->nr_pages, sizeof(struct page *),
GFP_KERNEL | __GFP_NOFAIL);
if (!be->compressed_pages)
be->compressed_pages =
kvcalloc(pclusterpages, sizeof(struct page *),
GFP_KERNEL | __GFP_NOFAIL);
z_erofs_parse_out_bvecs(be);
err2 = z_erofs_parse_in_bvecs(be, &overlapped);
if (err2)
err = err2;
if (err)
goto out;
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 = be->sb,
.in = be->compressed_pages,
.out = be->decompressed_pages,
.pageofs_in = pcl->pageofs_in,
.pageofs_out = pcl->pageofs_out,
.inputsize = inputsize,
.outputsize = pcl->length,
.alg = pcl->algorithmformat,
.inplace_io = overlapped,
.partial_decoding = pcl->partial,
.fillgaps = pcl->multibases,
}, be->pagepool);
out:
/* must handle all compressed pages before actual file pages */
if (z_erofs_is_inline_pcluster(pcl)) {
page = pcl->compressed_bvecs[0].page;
WRITE_ONCE(pcl->compressed_bvecs[0].page, NULL);
put_page(page);
} else {
for (i = 0; i < pclusterpages; ++i) {
page = pcl->compressed_bvecs[i].page;
if (erofs_page_is_managed(sbi, page))
continue;
/* recycle all individual short-lived pages */
(void)z_erofs_put_shortlivedpage(be->pagepool, page);
WRITE_ONCE(pcl->compressed_bvecs[i].page, NULL);
}
}
if (be->compressed_pages < be->onstack_pages ||
be->compressed_pages >= be->onstack_pages + Z_EROFS_ONSTACK_PAGES)
kvfree(be->compressed_pages);
z_erofs_fill_other_copies(be, err);
for (i = 0; i < be->nr_pages; ++i) {
page = be->decompressed_pages[i];
if (!page)
continue;
DBG_BUGON(z_erofs_page_is_invalidated(page));
/* recycle all individual short-lived pages */
if (z_erofs_put_shortlivedpage(be->pagepool, page))
continue;
if (err)
z_erofs_page_mark_eio(page);
z_erofs_onlinepage_endio(page);
}
if (be->decompressed_pages != be->onstack_pages)
kvfree(be->decompressed_pages);
pcl->length = 0;
pcl->partial = true;
pcl->multibases = false;
pcl->bvset.nextpage = NULL;
pcl->vcnt = 0;
/* pcluster lock MUST be taken before the following line */
WRITE_ONCE(pcl->next, Z_EROFS_PCLUSTER_NIL);
mutex_unlock(&pcl->lock);
return err;
}
static void z_erofs_decompress_queue(const struct z_erofs_decompressqueue *io,
struct page **pagepool)
{
struct z_erofs_decompress_backend be = {
.sb = io->sb,
.pagepool = pagepool,
.decompressed_secondary_bvecs =
LIST_HEAD_INIT(be.decompressed_secondary_bvecs),
};
z_erofs_next_pcluster_t owned = io->head;
while (owned != Z_EROFS_PCLUSTER_TAIL_CLOSED) {
/* impossible that 'owned' equals Z_EROFS_WORK_TPTR_TAIL */
DBG_BUGON(owned == Z_EROFS_PCLUSTER_TAIL);
/* impossible that 'owned' equals Z_EROFS_PCLUSTER_NIL */
DBG_BUGON(owned == Z_EROFS_PCLUSTER_NIL);
be.pcl = container_of(owned, struct z_erofs_pcluster, next);
owned = READ_ONCE(be.pcl->next);
z_erofs_decompress_pcluster(&be, io->eio ? -EIO : 0);
erofs_workgroup_put(&be.pcl->obj);
}
}
static void z_erofs_decompressqueue_work(struct work_struct *work)
{
struct z_erofs_decompressqueue *bgq =
container_of(work, struct z_erofs_decompressqueue, u.work);
struct page *pagepool = NULL;
DBG_BUGON(bgq->head == Z_EROFS_PCLUSTER_TAIL_CLOSED);
z_erofs_decompress_queue(bgq, &pagepool);
erofs_release_pages(&pagepool);
kvfree(bgq);
}
static 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) {
if (!atomic_add_return(bios, &io->pending_bios))
complete(&io->u.done);
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);
/* enable sync decompression for readahead */
if (sbi->opt.sync_decompress == EROFS_SYNC_DECOMPRESS_AUTO)
sbi->opt.sync_decompress = EROFS_SYNC_DECOMPRESS_FORCE_ON;
return;
}
z_erofs_decompressqueue_work(&io->u.work);
}
static struct page *pickup_page_for_submission(struct z_erofs_pcluster *pcl,
unsigned int nr,
struct page **pagepool,
struct address_space *mc)
{
const pgoff_t index = pcl->obj.index;
gfp_t gfp = mapping_gfp_mask(mc);
bool tocache = false;
struct address_space *mapping;
struct page *oldpage, *page;
compressed_page_t t;
int justfound;
repeat:
page = READ_ONCE(pcl->compressed_bvecs[nr].page);
oldpage = page;
if (!page)
goto out_allocpage;
/* process the target tagged pointer */
t = tagptr_init(compressed_page_t, page);
justfound = tagptr_unfold_tags(t);
page = tagptr_unfold_ptr(t);
/*
* preallocated cached pages, which is used to avoid direct reclaim
* otherwise, it will go inplace I/O path instead.
*/
if (page->private == Z_EROFS_PREALLOCATED_PAGE) {
WRITE_ONCE(pcl->compressed_bvecs[nr].page, 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_bvecs[nr].page, page);
if (!PagePrivate(page)) {
/*
* impossible to be !PagePrivate(page) for
* the current restriction as well if
* the page is already in compressed_bvecs[].
*/
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_bvecs[nr].page,
oldpage, page)) {
erofs_pagepool_add(pagepool, page);
cond_resched();
goto repeat;
}
out_tocache:
if (!tocache || add_to_page_cache_lru(page, mc, index + nr, gfp)) {
/* turn into temporary page if fails (1 ref) */
set_page_private(page, Z_EROFS_SHORTLIVED_PAGE);
goto out;
}
attach_page_private(page, pcl);
/* drop a refcount added by allocpage (then we have 2 refs here) */
put_page(page);
out: /* the only exit (for tracing and debugging) */
return page;
}
static struct z_erofs_decompressqueue *
jobqueue_init(struct super_block *sb,
struct z_erofs_decompressqueue *fgq, bool *fg)
{
struct z_erofs_decompressqueue *q;
if (fg && !*fg) {
q = kvzalloc(sizeof(*q), GFP_KERNEL | __GFP_NOWARN);
if (!q) {
*fg = true;
goto fg_out;
}
INIT_WORK(&q->u.work, z_erofs_decompressqueue_work);
} else {
fg_out:
q = fgq;
init_completion(&fgq->u.done);
atomic_set(&fgq->pending_bios, 0);
q->eio = false;
}
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_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 (erofs_page_is_managed(EROFS_SB(q->sb), page)) {
if (!err)
SetPageUptodate(page);
unlock_page(page);
}
}
if (err)
q->eio = true;
z_erofs_decompress_kickoff(q, tagptr_unfold_tags(t), -1);
bio_put(bio);
}
static void z_erofs_submit_queue(struct z_erofs_decompress_frontend *f,
struct page **pagepool,
struct z_erofs_decompressqueue *fgq,
bool *force_fg)
{
struct super_block *sb = f->inode->i_sb;
struct address_space *mc = MNGD_MAPPING(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->owned_head;
/* bio is NULL initially, so no need to initialize last_{index,bdev} */
pgoff_t last_index;
struct block_device *last_bdev;
unsigned int nr_bios = 0;
struct bio *bio = NULL;
bi_private = jobqueueset_init(sb, q, fgq, force_fg);
qtail[JQ_BYPASS] = &q[JQ_BYPASS]->head;
qtail[JQ_SUBMIT] = &q[JQ_SUBMIT]->head;
/* by default, all need io submission */
q[JQ_SUBMIT]->head = owned_head;
do {
struct erofs_map_dev mdev;
struct z_erofs_pcluster *pcl;
pgoff_t cur, end;
unsigned int i = 0;
bool bypass = true;
/* no possible 'owned_head' equals the following */
DBG_BUGON(owned_head == Z_EROFS_PCLUSTER_TAIL_CLOSED);
DBG_BUGON(owned_head == Z_EROFS_PCLUSTER_NIL);
pcl = container_of(owned_head, struct z_erofs_pcluster, next);
/* close the main owned chain at first */
owned_head = cmpxchg(&pcl->next, Z_EROFS_PCLUSTER_TAIL,
Z_EROFS_PCLUSTER_TAIL_CLOSED);
if (z_erofs_is_inline_pcluster(pcl)) {
move_to_bypass_jobqueue(pcl, qtail, owned_head);
continue;
}
/* no device id here, thus it will always succeed */
mdev = (struct erofs_map_dev) {
.m_pa = blknr_to_addr(pcl->obj.index),
};
(void)erofs_map_dev(sb, &mdev);
cur = erofs_blknr(mdev.m_pa);
end = cur + pcl->pclusterpages;
do {
struct page *page;
page = pickup_page_for_submission(pcl, i++, pagepool,
mc);
if (!page)
continue;
if (bio && (cur != last_index + 1 ||
last_bdev != mdev.m_bdev)) {
submit_bio_retry:
submit_bio(bio);
bio = NULL;
}
if (!bio) {
bio = bio_alloc(mdev.m_bdev, BIO_MAX_VECS,
REQ_OP_READ, GFP_NOIO);
bio->bi_end_io = z_erofs_decompressqueue_endio;
last_bdev = mdev.m_bdev;
bio->bi_iter.bi_sector = (sector_t)cur <<
LOG_SECTORS_PER_BLOCK;
bio->bi_private = bi_private;
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 z_erofs_decompress_frontend *f,
struct page **pagepool, bool force_fg)
{
struct z_erofs_decompressqueue io[NR_JOBQUEUES];
if (f->owned_head == Z_EROFS_PCLUSTER_TAIL)
return;
z_erofs_submit_queue(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 */
wait_for_completion_io(&io[JQ_SUBMIT].u.done);
/* handle synchronous decompress queue in the caller context */
z_erofs_decompress_queue(&io[JQ_SUBMIT], pagepool);
}
/*
* Since partial uptodate is still unimplemented for now, we have to use
* approximate readmore strategies as a start.
*/
static void z_erofs_pcluster_readmore(struct z_erofs_decompress_frontend *f,
struct readahead_control *rac,
erofs_off_t end,
struct page **pagepool,
bool backmost)
{
struct inode *inode = f->inode;
struct erofs_map_blocks *map = &f->map;
erofs_off_t cur;
int err;
if (backmost) {
map->m_la = end;
err = z_erofs_map_blocks_iter(inode, map,
EROFS_GET_BLOCKS_READMORE);
if (err)
return;
/* expend ra for the trailing edge if readahead */
if (rac) {
loff_t newstart = readahead_pos(rac);
cur = round_up(map->m_la + map->m_llen, PAGE_SIZE);
readahead_expand(rac, newstart, cur - newstart);
return;
}
end = round_up(end, PAGE_SIZE);
} else {
end = round_up(map->m_la, PAGE_SIZE);
if (!map->m_llen)
return;
}
cur = map->m_la + map->m_llen - 1;
while (cur >= end) {
pgoff_t index = cur >> PAGE_SHIFT;
struct page *page;
page = erofs_grab_cache_page_nowait(inode->i_mapping, index);
if (page) {
if (PageUptodate(page)) {
unlock_page(page);
} else {
err = z_erofs_do_read_page(f, page, pagepool);
if (err)
erofs_err(inode->i_sb,
"readmore error at page %lu @ nid %llu",
index, EROFS_I(inode)->nid);
}
put_page(page);
}
if (cur < PAGE_SIZE)
break;
cur = (index << PAGE_SHIFT) - 1;
}
}
static int z_erofs_read_folio(struct file *file, struct folio *folio)
{
struct page *page = &folio->page;
struct inode *const inode = page->mapping->host;
struct erofs_sb_info *const sbi = EROFS_I_SB(inode);
struct z_erofs_decompress_frontend f = DECOMPRESS_FRONTEND_INIT(inode);
struct page *pagepool = NULL;
int err;
trace_erofs_readpage(page, false);
f.headoffset = (erofs_off_t)page->index << PAGE_SHIFT;
z_erofs_pcluster_readmore(&f, NULL, f.headoffset + PAGE_SIZE - 1,
&pagepool, true);
err = z_erofs_do_read_page(&f, page, &pagepool);
z_erofs_pcluster_readmore(&f, NULL, 0, &pagepool, false);
(void)z_erofs_collector_end(&f);
/* if some compressed cluster ready, need submit them anyway */
z_erofs_runqueue(&f, &pagepool,
z_erofs_get_sync_decompress_policy(sbi, 0));
if (err)
erofs_err(inode->i_sb, "failed to read, err [%d]", err);
erofs_put_metabuf(&f.map.buf);
erofs_release_pages(&pagepool);
return err;
}
static void z_erofs_readahead(struct readahead_control *rac)
{
struct inode *const inode = rac->mapping->host;
struct erofs_sb_info *const sbi = EROFS_I_SB(inode);
struct z_erofs_decompress_frontend f = DECOMPRESS_FRONTEND_INIT(inode);
struct page *pagepool = NULL, *head = NULL, *page;
unsigned int nr_pages;
f.readahead = true;
f.headoffset = readahead_pos(rac);
z_erofs_pcluster_readmore(&f, rac, f.headoffset +
readahead_length(rac) - 1, &pagepool, true);
nr_pages = readahead_count(rac);
trace_erofs_readpages(inode, readahead_index(rac), nr_pages, false);
while ((page = readahead_page(rac))) {
set_page_private(page, (unsigned long)head);
head = page;
}
while (head) {
struct page *page = head;
int err;
/* traversal in reverse order */
head = (void *)page_private(page);
err = z_erofs_do_read_page(&f, page, &pagepool);
if (err)
erofs_err(inode->i_sb,
"readahead error at page %lu @ nid %llu",
page->index, EROFS_I(inode)->nid);
put_page(page);
}
z_erofs_pcluster_readmore(&f, rac, 0, &pagepool, false);
(void)z_erofs_collector_end(&f);
z_erofs_runqueue(&f, &pagepool,
z_erofs_get_sync_decompress_policy(sbi, nr_pages));
erofs_put_metabuf(&f.map.buf);
erofs_release_pages(&pagepool);
}
const struct address_space_operations z_erofs_aops = {
.read_folio = z_erofs_read_folio,
.readahead = z_erofs_readahead,
};