// 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)
{
int ret;
bool occupied;
/* give priority for inplaceio */
if (clt->mode >= COLLECT_PRIMARY &&
type == Z_EROFS_PAGE_TYPE_EXCLUSIVE &&
z_erofs_try_inplace_io(clt, page))
return 0;
ret = z_erofs_pagevec_enqueue(&clt->vector,
page, type, &occupied);
clt->cl->vcnt += (unsigned int)ret;
return ret ? 0 : -EAGAIN;
}
static void z_erofs_try_to_claim_pcluster(struct z_erofs_collector *clt)
{
struct z_erofs_pcluster *pcl = clt->pcl;
z_erofs_next_pcluster_t *owned_head = &clt->owned_head;
/* type 1, nil pcluster (this pcluster doesn't belong to any chain.) */
if (cmpxchg(&pcl->next, Z_EROFS_PCLUSTER_NIL,
*owned_head) == Z_EROFS_PCLUSTER_NIL) {
*owned_head = &pcl->next;
/* so we can attach this pcluster to our submission chain. */
clt->mode = COLLECT_PRIMARY_FOLLOWED;
return;
}
/*
* type 2, link to the end of an existing open chain, be careful
* that its submission is controlled by the original attached chain.
*/
if (cmpxchg(&pcl->next, Z_EROFS_PCLUSTER_TAIL,
*owned_head) == Z_EROFS_PCLUSTER_TAIL) {
*owned_head = Z_EROFS_PCLUSTER_TAIL;
clt->mode = COLLECT_PRIMARY_HOOKED;
clt->tailpcl = NULL;
return;
}
/* type 3, it belongs to a chain, but it isn't the end of the chain */
clt->mode = COLLECT_PRIMARY;
}
static int z_erofs_lookup_collection(struct z_erofs_collector *clt,
struct inode *inode,
struct erofs_map_blocks *map)
{
struct z_erofs_pcluster *pcl = clt->pcl;
struct z_erofs_collection *cl;
unsigned int length;
/* to avoid unexpected loop formed by corrupted images */
if (clt->owned_head == &pcl->next || pcl == clt->tailpcl) {
DBG_BUGON(1);
return -EFSCORRUPTED;
}
cl = z_erofs_primarycollection(pcl);
if (cl->pageofs != (map->m_la & ~PAGE_MASK)) {
DBG_BUGON(1);
return -EFSCORRUPTED;
}
length = READ_ONCE(pcl->length);
if (length & Z_EROFS_PCLUSTER_FULL_LENGTH) {
if ((map->m_llen << Z_EROFS_PCLUSTER_LENGTH_BIT) > length) {
DBG_BUGON(1);
return -EFSCORRUPTED;
}
} else {
unsigned int llen = map->m_llen << Z_EROFS_PCLUSTER_LENGTH_BIT;
if (map->m_flags & EROFS_MAP_FULL_MAPPED)
llen |= Z_EROFS_PCLUSTER_FULL_LENGTH;
while (llen > length &&
length != cmpxchg_relaxed(&pcl->length, length, llen)) {
cpu_relax();
length = READ_ONCE(pcl->length);
}
}
mutex_lock(&cl->lock);
/* used to check tail merging loop due to corrupted images */
if (clt->owned_head == Z_EROFS_PCLUSTER_TAIL)
clt->tailpcl = pcl;
z_erofs_try_to_claim_pcluster(clt);
clt->cl = cl;
return 0;
}
static int z_erofs_register_collection(struct z_erofs_collector *clt,
struct inode *inode,
struct erofs_map_blocks *map)
{
struct z_erofs_pcluster *pcl;
struct z_erofs_collection *cl;
struct erofs_workgroup *grp;
int err;
/* 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);
/* should allocate an additional short-lived page for pagevec */
if (err == -EAGAIN) {
struct page *const newpage =
alloc_page(GFP_NOFS | __GFP_NOFAIL);
set_page_private(newpage, Z_EROFS_SHORTLIVED_PAGE);
err = z_erofs_attach_page(clt, newpage,
Z_EROFS_PAGE_TYPE_EXCLUSIVE);
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_VECS);
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,
};
VisionFive2 Linux kernel
StarFive Tech Linux Kernel for VisionFive (JH7110) boards (mirror)
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