// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2018 HUAWEI, Inc.
* https://www.huawei.com/
* Copyright (C) 2022 Alibaba Cloud
*/
#include "compress.h"
#include <linux/psi.h>
#include <linux/cpuhotplug.h>
#include <trace/events/erofs.h>
#define Z_EROFS_PCLUSTER_MAX_PAGES (Z_EROFS_PCLUSTER_MAX_SIZE / PAGE_SIZE)
#define Z_EROFS_INLINE_BVECS 2
/*
* let's leave a type here in case of introducing
* another tagged pointer later.
*/
typedef void *z_erofs_next_pcluster_t;
struct z_erofs_bvec {
struct page *page;
int offset;
unsigned int end;
};
#define __Z_EROFS_BVSET(name, total) \
struct name { \
/* point to the next page which contains the following bvecs */ \
struct page *nextpage; \
struct z_erofs_bvec bvec[total]; \
}
__Z_EROFS_BVSET(z_erofs_bvset,);
__Z_EROFS_BVSET(z_erofs_bvset_inline, Z_EROFS_INLINE_BVECS);
/*
* Structure fields follow one of the following exclusion rules.
*
* I: Modifiable by initialization/destruction paths and read-only
* for everyone else;
*
* L: Field should be protected by the pcluster lock;
*
* A: Field should be accessed / updated in atomic for parallelized code.
*/
struct z_erofs_pcluster {
struct erofs_workgroup obj;
struct mutex lock;
/* A: point to next chained pcluster or TAILs */
z_erofs_next_pcluster_t next;
/* L: the maximum decompression size of this round */
unsigned int length;
/* L: total number of bvecs */
unsigned int vcnt;
/* I: pcluster size (compressed size) in bytes */
unsigned int pclustersize;
/* I: page offset of start position of decompression */
unsigned short pageofs_out;
/* I: page offset of inline compressed data */
unsigned short pageofs_in;
union {
/* L: inline a certain number of bvec for bootstrap */
struct z_erofs_bvset_inline bvset;
/* I: can be used to free the pcluster by RCU. */
struct rcu_head rcu;
};
/* I: compression algorithm format */
unsigned char algorithmformat;
/* L: whether partial decompression or not */
bool partial;
/* L: indicate several pageofs_outs or not */
bool multibases;
/* L: whether extra buffer allocations are best-effort */
bool besteffort;
/* A: compressed bvecs (can be cached or inplaced pages) */
struct z_erofs_bvec compressed_bvecs[];
};
/* the end of a chain of pclusters */
#define Z_EROFS_PCLUSTER_TAIL ((void *) 0x700 + POISON_POINTER_DELTA)
#define Z_EROFS_PCLUSTER_NIL (NULL)
struct z_erofs_decompressqueue {
struct super_block *sb;
atomic_t pending_bios;
z_erofs_next_pcluster_t head;
union {
struct completion done;
struct work_struct work;
struct kthread_work kthread_work;
} u;
bool eio, sync;
};
static inline bool z_erofs_is_inline_pcluster(struct z_erofs_pcluster *pcl)
{
return !pcl->obj.index;
}
static inline unsigned int z_erofs_pclusterpages(struct z_erofs_pcluster *pcl)
{
return PAGE_ALIGN(pcl->pclustersize) >> PAGE_SHIFT;
}
#define MNGD_MAPPING(sbi) ((sbi)->managed_cache->i_mapping)
static bool erofs_folio_is_managed(struct erofs_sb_info *sbi, struct folio *fo)
{
return fo->mapping == MNGD_MAPPING(sbi);
}
#define Z_EROFS_ONSTACK_PAGES 32
/*
* 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,
struct page **pagepool)
{
if (iter->cur >= iter->nr) {
struct page *nextpage = *candidate_bvpage;
if (!nextpage) {
nextpage = __erofs_allocpage(pagepool, GFP_KERNEL,
true);
if (!nextpage)
return -ENOMEM;
set_page_private(nextpage, Z_EROFS_SHORTLIVED_PAGE);
}
DBG_BUGON(iter->bvset->nextpage);
iter->bvset->nextpage = nextpage;
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 size)
{
unsigned int nrpages = PAGE_ALIGN(size) >> PAGE_SHIFT;
struct z_erofs_pcluster_slab *pcs = pcluster_pool;
for (; pcs < pcluster_pool + ARRAY_SIZE(pcluster_pool); ++pcs) {
struct z_erofs_pcluster *pcl;
if (nrpages > pcs->maxpages)
continue;
pcl = kmem_cache_zalloc(pcs->slab, GFP_KERNEL);
if (!pcl)
return ERR_PTR(-ENOMEM);
pcl->pclustersize = size;
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);
}
static struct workqueue_struct *z_erofs_workqueue __read_mostly;
#ifdef CONFIG_EROFS_FS_PCPU_KTHREAD
static struct kthread_worker __rcu **z_erofs_pcpu_workers;
static void erofs_destroy_percpu_workers(void)
{
struct kthread_worker *worker;
unsigned int cpu;
for_each_possible_cpu(cpu) {
worker = rcu_dereference_protected(
z_erofs_pcpu_workers[cpu], 1);
rcu_assign_pointer(z_erofs_pcpu_workers[cpu], NULL);
if (worker)
kthread_destroy_worker(worker);
}
kfree(z_erofs_pcpu_workers);
}
static struct kthread_worker *erofs_init_percpu_worker(int cpu)
{
struct kthread_worker *worker =
kthread_create_worker_on_cpu(cpu, 0, "erofs_worker/%u", cpu);
if (IS_ERR(worker))
return worker;
if (IS_ENABLED(CONFIG_EROFS_FS_PCPU_KTHREAD_HIPRI))
sched_set_fifo_low(worker->task);
return worker;
}
static int erofs_init_percpu_workers(void)
{
struct kthread_worker *worker;
unsigned int cpu;
z_erofs_pcpu_workers = kcalloc(num_possible_cpus(),
sizeof(struct kthread_worker *), GFP_ATOMIC);
if (!z_erofs_pcpu_workers)
return -ENOMEM;
for_each_online_cpu(cpu) { /* could miss cpu{off,on}line? */
worker = erofs_init_percpu_worker(cpu);
if (!IS_ERR(worker))
rcu_assign_pointer(z_erofs_pcpu_workers[cpu], worker);
}
return 0;
}
#else
static inline void erofs_destroy_percpu_workers(void) {}
static inline int erofs_init_percpu_workers(void) { return 0; }
#endif
#if defined(CONFIG_HOTPLUG_CPU) && defined(CONFIG_EROFS_FS_PCPU_KTHREAD)
static DEFINE_SPINLOCK(z_erofs_pcpu_worker_lock);
static enum cpuhp_state erofs_cpuhp_state;
static int erofs_cpu_online(unsigned int cpu)
{
struct kthread_worker *worker, *old;
worker = erofs_init_percpu_worker(cpu);
if (IS_ERR(worker))
return PTR_ERR(worker);
spin_lock(&z_erofs_pcpu_worker_lock);
old = rcu_dereference_protected(z_erofs_pcpu_workers[cpu],
lockdep_is_held(&z_erofs_pcpu_worker_lock));
if (!old)
rcu_assign_pointer(z_erofs_pcpu_workers[cpu], worker);
spin_unlock(&z_erofs_pcpu_worker_lock);
if (old)
kthread_destroy_worker(worker);
return 0;
}
static int erofs_cpu_offline(unsigned int cpu)
{
struct kthread_worker *worker;
spin_lock(&z_erofs_pcpu_worker_lock);
worker = rcu_dereference_protected(z_erofs_pcpu_workers[cpu],
lockdep_is_held(&z_erofs_pcpu_worker_lock));
rcu_assign_pointer(z_erofs_pcpu_workers[cpu], NULL);
spin_unlock(&z_erofs_pcpu_worker_lock);
synchronize_rcu();
if (worker)
kthread_destroy_worker(worker);
return 0;
}
static int erofs_cpu_hotplug_init(void)
{
int state;
state = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN,
"fs/erofs:online", erofs_cpu_online, erofs_cpu_offline);
if (state < 0)
return state;
erofs_cpuhp_state = state;
return 0;
}
static void erofs_cpu_hotplug_destroy(void)
{
if (erofs_cpuhp_state)
cpuhp_remove_state_nocalls(erofs_cpuhp_state);
}
#else /* !CONFIG_HOTPLUG_CPU || !CONFIG_EROFS_FS_PCPU_KTHREAD */
static inline int erofs_cpu_hotplug_init(void) { return 0; }
static inline void erofs_cpu_hotplug_destroy(void) {}
#endif
void z_erofs_exit_subsystem(void)
{
erofs_cpu_hotplug_destroy();
erofs_destroy_percpu_workers();
destroy_workqueue(z_erofs_workqueue);
z_erofs_destroy_pcluster_pool();
z_erofs_exit_decompressor();
}
int __init z_erofs_init_subsystem(void)
{
int err = z_erofs_init_decompressor();
if (err)
goto err_decompressor;
err = z_erofs_create_pcluster_pool();
if (err)
goto err_pcluster_pool;
z_erofs_workqueue = alloc_workqueue("erofs_worker",
WQ_UNBOUND | WQ_HIGHPRI, num_possible_cpus());
if (!z_erofs_workqueue) {
err = -ENOMEM;
goto err_workqueue_init;
}
err = erofs_init_percpu_workers();
if (err)
goto err_pcpu_worker;
err = erofs_cpu_hotplug_init();
if (err < 0)
goto err_cpuhp_init;
return err;
err_cpuhp_init:
erofs_destroy_percpu_workers();
err_pcpu_worker:
destroy_workqueue(z_erofs_workqueue);
err_workqueue_init:
z_erofs_destroy_pcluster_pool();
err_pcluster_pool:
z_erofs_exit_decompressor();
err_decompressor:
return err;
}
enum z_erofs_pclustermode {
Z_EROFS_PCLUSTER_INFLIGHT,
/*
* 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 pcluster was just linked to a decompression chain by us. It can
* also be linked with the remaining pclusters, which means if the
* processing page is the tail page of a pcluster, this pcluster can
* safely use the whole page (since the previous pcluster is within the
* same chain) for in-place I/O, as illustrated below:
* ___________________________________________________
* | tail (partial) page | head (partial) page |
* | (of the current pcl) | (of the previous pcl) |
* |___PCLUSTER_FOLLOWED___|_____PCLUSTER_FOLLOWED_____|
*
* [ (*) the page above 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 *pagepool;
struct page *candidate_bvpage;
struct z_erofs_pcluster *pcl;
z_erofs_next_pcluster_t owned_head;
enum z_erofs_pclustermode mode;
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 }
static bool z_erofs_should_alloc_cache(struct z_erofs_decompress_frontend *fe)
{
unsigned int cachestrategy = EROFS_I_SB(fe->inode)->opt.cache_strategy;
if (cachestrategy <= EROFS_ZIP_CACHE_DISABLED)
return false;
if (!(fe->map.m_flags & EROFS_MAP_FULL_MAPPED))
return true;
if (cachestrategy >= EROFS_ZIP_CACHE_READAROUND &&
fe->map.m_la < fe->headoffset)
return true;
return false;
}
static void z_erofs_bind_cache(struct z_erofs_decompress_frontend *fe)
{
struct address_space *mc = MNGD_MAPPING(EROFS_I_SB(fe->inode));
struct z_erofs_pcluster *pcl = fe->pcl;
unsigned int pclusterpages = z_erofs_pclusterpages(pcl);
bool shouldalloc = z_erofs_should_alloc_cache(fe);
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 (i_blocksize(fe->inode) != PAGE_SIZE ||
fe->mode < Z_EROFS_PCLUSTER_FOLLOWED)
return;
for (i = 0; i < pclusterpages; ++i) {
struct page *page, *newpage;
/* Inaccurate check w/o locking to avoid unneeded lookups */
if (READ_ONCE(pcl->compressed_bvecs[i].page))
continue;
page = find_get_page(mc, pcl->obj.index + i);
if (!page) {
/* I/O is needed, no possible to decompress directly */
standalone = false;
if (!shouldalloc)
continue;
/*
* Try cached I/O if allocation succeeds or fallback to
* in-place I/O instead to avoid any direct reclaim.
*/
newpage = erofs_allocpage(&fe->pagepool, gfp);
if (!newpage)
continue;
set_page_private(newpage, Z_EROFS_PREALLOCATED_PAGE);
}
spin_lock(&pcl->obj.lockref.lock);
if (!pcl->compressed_bvecs[i].page) {
pcl->compressed_bvecs[i].page = page ? page : newpage;
spin_unlock(&pcl->obj.lockref.lock);
continue;
}
spin_unlock(&pcl->obj.lockref.lock);
if (page)
put_page(page);
else if (newpage)
erofs_pagepool_add(&fe->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;
}
/* (erofs_shrinker) disconnect cached encoded data with pclusters */
int erofs_try_to_free_all_cached_folios(struct erofs_sb_info *sbi,
struct erofs_workgroup *grp)
{
struct z_erofs_pcluster *const pcl =
container_of(grp, struct z_erofs_pcluster, obj);
unsigned int pclusterpages = z_erofs_pclusterpages(pcl);
struct folio *folio;
int i;
DBG_BUGON(z_erofs_is_inline_pcluster(pcl));
/* Each cached folio contains one page unless bs > ps is supported */
for (i = 0; i < pclusterpages; ++i) {
if (pcl->compressed_bvecs[i].page) {
folio = page_folio(pcl->compressed_bvecs[i].page);
/* Avoid reclaiming or migrating this folio */
if (!folio_trylock(folio))
return -EBUSY;
if (!erofs_folio_is_managed(sbi, folio))
continue;
pcl->compressed_bvecs[i].page = NULL;
folio_detach_private(folio);
folio_unlock(folio);
}
}
return 0;
}
static bool z_erofs_cache_release_folio(struct folio *folio, gfp_t gfp)
{
struct z_erofs_pcluster *pcl = folio_get_private(folio);
struct z_erofs_bvec *bvec = pcl->compressed_bvecs;
struct z_erofs_bvec *end = bvec + z_erofs_pclusterpages(pcl);
bool ret;
if (!folio_test_private(folio))
return true;
ret = false;
spin_lock(&pcl->obj.lockref.lock);
if (pcl->obj.lockref.count <= 0) {
DBG_BUGON(z_erofs_is_inline_pcluster(pcl));
for (; bvec < end; ++bvec) {
if (bvec->page && page_folio(bvec->page) == folio) {
bvec->page = NULL;
folio_detach_private(folio);
ret = true;
break;
}
}
}
spin_unlock(&pcl->obj.lockref.lock);
return ret;
}
/*
* It will be called only on inode eviction. In case that there are still some
* decompression requests in progress, wait with rescheduling for a bit here.
* An extra lock could be introduced instead but it seems unnecessary.
*/
static void z_erofs_cache_invalidate_folio(struct folio *folio,
size_t offset, size_t length)
{
const size_t stop = length + offset;
/* Check for potential overflow in debug mode */
DBG_BUGON(stop > folio_size(folio) || stop < length);
if (offset == 0 && stop == folio_size(folio))
while (!z_erofs_cache_release_folio(folio, 0))
cond_resched();
}
static const struct address_space_operations z_erofs_cache_aops = {
.release_folio = z_erofs_cache_release_folio,
.invalidate_folio = z_erofs_cache_invalidate_folio,
};
int erofs_init_managed_cache(struct super_block *sb)
{
struct inode *const inode = new_inode(sb);
if (!inode)
return -ENOMEM;
set_nlink(inode, 1);
inode->i_size = OFFSET_MAX;
inode->i_mapping->a_ops = &z_erofs_cache_aops;
mapping_set_gfp_mask(inode->i_mapping, GFP_KERNEL);
EROFS_SB(sb)->managed_cache = inode;
return 0;
}
/* 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)
{
struct z_erofs_pcluster *pcl = fe->pcl;
int ret;
if (exclusive) {
/* give priority for inplaceio to use file pages first */
spin_lock(&pcl->obj.lockref.lock);
while (fe->icur > 0) {
if (pcl->compressed_bvecs[--fe->icur].page)
continue;
pcl->compressed_bvecs[fe->icur] = *bvec;
spin_unlock(&pcl->obj.lockref.lock);
return 0;
}
spin_unlock(&pcl->obj.lockref.lock);
/* 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->pagepool);
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, it belongs to an ongoing 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;
struct super_block *sb = fe->inode->i_sb;
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) ||
(!ztailpacking && !erofs_blknr(sb, map->m_pa))) {
DBG_BUGON(1);
return -EFSCORRUPTED;
}
/* no available pcluster, let's allocate one */
pcl = z_erofs_alloc_pcluster(map->m_plen);
if (IS_ERR(pcl))
return PTR_ERR(pcl);
spin_lock_init(&pcl->obj.lockref.lock);
pcl->obj.lockref.count = 1; /* one ref for this request */
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 */
} else {
pcl->obj.index = erofs_blknr(sb, map->m_pa);
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;
}
}
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_pcluster_begin(struct z_erofs_decompress_frontend *fe)
{
struct erofs_map_blocks *map = &fe->map;
struct super_block *sb = fe->inode->i_sb;
erofs_blk_t blknr = erofs_blknr(sb, map->m_pa);
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);
if (!(map->m_flags & EROFS_MAP_META)) {
grp = erofs_find_workgroup(sb, blknr);
} 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);
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);
if (!z_erofs_is_inline_pcluster(fe->pcl)) {
/* bind cache first when cached decompression is preferred */
z_erofs_bind_cache(fe);
} else {
void *mptr;
mptr = erofs_read_metabuf(&map->buf, sb, map->m_pa, EROFS_NO_KMAP);
if (IS_ERR(mptr)) {
ret = PTR_ERR(mptr);
erofs_err(sb, "failed to get inline data %d", ret);
return ret;
}
get_page(map->buf.page);
WRITE_ONCE(fe->pcl->compressed_bvecs[0].page, map->buf.page);
fe->pcl->pageofs_in = map->m_pa & ~PAGE_MASK;
fe->mode = Z_EROFS_PCLUSTER_FOLLOWED_NOINPLACE;
}
/* file-backed inplace I/O 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 void z_erofs_pcluster_end(struct z_erofs_decompress_frontend *fe)
{
struct z_erofs_pcluster *pcl = fe->pcl;
if (!pcl)
return;
z_erofs_bvec_iter_end(&fe->biter);
mutex_unlock(&pcl->lock);
if (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;
}
static int z_erofs_read_fragment(struct super_block *sb, struct folio *folio,
unsigned int cur, unsigned int end, erofs_off_t pos)
{
struct inode *packed_inode = EROFS_SB(sb)->packed_inode;
struct erofs_buf buf = __EROFS_BUF_INITIALIZER;
unsigned int cnt;
u8 *src;
if (!packed_inode)
return -EFSCORRUPTED;
buf.mapping = packed_inode->i_mapping;
for (; cur < end; cur += cnt, pos += cnt) {
cnt = min(end - cur, sb->s_blocksize - erofs_blkoff(sb, pos));
src = erofs_bread(&buf, pos, EROFS_KMAP);
if (IS_ERR(src)) {
erofs_put_metabuf(&buf);
return PTR_ERR(src);
}
memcpy_to_folio(folio, cur, src, cnt);
}
erofs_put_metabuf(&buf);
return 0;
}
static int z_erofs_scan_folio(struct z_erofs_decompress_frontend *f,
struct folio *folio, bool ra)
{
struct inode *const inode = f->inode;
struct erofs_map_blocks *const map = &f->map;
const loff_t offset = folio_pos(folio);
const unsigned int bs = i_blocksize(inode);
unsigned int end = folio_size(folio), split = 0, cur, pgs;
bool tight, excl;
int err = 0;
tight = (bs == PAGE_SIZE);
erofs_onlinefolio_init(folio);
do {
if (offset + end - 1 < map->m_la ||
offset + end - 1 >= map->m_la + map->m_llen) {
z_erofs_pcluster_end(f);
map->m_la = offset + end - 1;
map->m_llen = 0;
err = z_erofs_map_blocks_iter(inode, map, 0);
if (err)
break;
}
cur = offset > map->m_la ? 0 : map->m_la - offset;
pgs = round_down(cur, PAGE_SIZE);
/* bump split parts first to avoid several separate cases */
++split;
if (!(map->m_flags & EROFS_MAP_MAPPED)) {
folio_zero_segment(folio, cur, end);
tight = false;
} else if (map->m_flags & EROFS_MAP_FRAGMENT) {
erofs_off_t fpos = offset + cur - map->m_la;
err = z_erofs_read_fragment(inode->i_sb, folio, cur,
cur + min(map->m_llen - fpos, end - cur),
EROFS_I(inode)->z_fragmentoff + fpos);
if (err)
break;
tight = false;
} else {
if (!f->pcl) {
err = z_erofs_pcluster_begin(f);
if (err)
break;
f->pcl->besteffort |= !ra;
}
pgs = round_down(end - 1, PAGE_SIZE);
/*
* Ensure this partial page belongs to this submit chain
* rather than other concurrent submit chains or
* noio(bypass) chains since those chains are handled
* asynchronously thus it cannot be used for inplace I/O
* or bvpage (should be processed in the strict order.)
*/
tight &= (f->mode >= Z_EROFS_PCLUSTER_FOLLOWED);
excl = false;
if (cur <= pgs) {
excl = (split <= 1) || tight;
cur = pgs;
}
err = z_erofs_attach_page(f, &((struct z_erofs_bvec) {
.page = folio_page(folio, pgs >> PAGE_SHIFT),
.offset = offset + pgs - map->m_la,
.end = end - pgs, }), excl);
if (err)
break;
erofs_onlinefolio_split(folio);
if (f->pcl->pageofs_out != (map->m_la & ~PAGE_MASK))
f->pcl->multibases = true;
if (f->pcl->length < offset + end - map->m_la) {
f->pcl->length = offset + end - map->m_la;
f->pcl->pageofs_out = map->m_la & ~PAGE_MASK;
}
if ((map->m_flags & EROFS_MAP_FULL_MAPPED) &&
!(map->m_flags & EROFS_MAP_PARTIAL_REF) &&
f->pcl->length == map->m_llen)
f->pcl->partial = false;
}
/* shorten the remaining extent to update progress */
map->m_llen = offset + cur - map->m_la;
map->m_flags &= ~EROFS_MAP_FULL_MAPPED;
if (cur <= pgs) {
split = cur < pgs;
tight = (bs == PAGE_SIZE);
}
} while ((end = cur) > 0);
erofs_onlinefolio_end(folio, err);
return err;
}
static bool z_erofs_is_sync_decompress(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_folio(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;
unsigned int pgnr;
if (!((bvec->offset + be->pcl->pageofs_out) & ~PAGE_MASK) &&
(bvec->end == PAGE_SIZE ||
bvec->offset + bvec->end == be->pcl->length)) {
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);
erofs_onlinefolio_end(page_folio(bvi->bvec.page), err);
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 data ought to be valid when decompressing */
if (IS_ERR(page) || !page) {
bvec->page = NULL; /* clear the failure reason */
err = page ? PTR_ERR(page) : -EIO;
continue;
}
be->compressed_pages[i] = page;
if (z_erofs_is_inline_pcluster(pcl) ||
erofs_folio_is_managed(EROFS_SB(be->sb), page_folio(page))) {
if (!PageUptodate(page))
err = -EIO;
continue;
}
DBG_BUGON(z_erofs_page_is_invalidated(page));
if (z_erofs_is_shortlived_page(page))
continue;
z_erofs_do_decompressed_bvec(be, bvec);
*overlapped = true;
}
return err;
}
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);
const struct z_erofs_decompressor *decomp =
z_erofs_decomp[pcl->algorithmformat];
int i, j, jtop, 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)
err = decomp->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 = pcl->pclustersize,
.outputsize = pcl->length,
.alg = pcl->algorithmformat,
.inplace_io = overlapped,
.partial_decoding = pcl->partial,
.fillgaps = pcl->multibases,
.gfp = pcl->besteffort ? GFP_KERNEL :
GFP_NOWAIT | __GFP_NORETRY
}, be->pagepool);
/* 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 {
/* managed folios are still left in compressed_bvecs[] */
for (i = 0; i < pclusterpages; ++i) {
page = be->compressed_pages[i];
if (!page ||
erofs_folio_is_managed(sbi, page_folio(page)))
continue;
(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);
jtop = 0;
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));
if (!z_erofs_is_shortlived_page(page)) {
erofs_onlinefolio_end(page_folio(page), err);
continue;
}
if (pcl->algorithmformat != Z_EROFS_COMPRESSION_LZ4) {
erofs_pagepool_add(be->pagepool, page);
continue;
}
for (j = 0; j < jtop && be->decompressed_pages[j] != page; ++j)
;
if (j >= jtop) /* this bounce page is newly detected */
be->decompressed_pages[jtop++] = page;
}
while (jtop)
erofs_pagepool_add(be->pagepool,
be->decompressed_pages[--jtop]);
if (be->decompressed_pages != be->onstack_pages)
kvfree(be->decompressed_pages);
pcl->length = 0;
pcl->partial = true;
pcl->multibases = false;
pcl->besteffort = 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 int 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;
int err = io->eio ? -EIO : 0;
while (owned != Z_EROFS_PCLUSTER_TAIL) {
DBG_BUGON(owned == Z_EROFS_PCLUSTER_NIL);
be.pcl = container_of(owned, struct z_erofs_pcluster, next);
owned = READ_ONCE(be.pcl->next);
err = z_erofs_decompress_pcluster(&be, err) ?: err;
if (z_erofs_is_inline_pcluster(be.pcl))
z_erofs_free_pcluster(be.pcl);
else
erofs_workgroup_put(&be.pcl->obj);
}
return err;
}
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);
z_erofs_decompress_queue(bgq, &pagepool);
erofs_release_pages(&pagepool);
kvfree(bgq);
}
#ifdef CONFIG_EROFS_FS_PCPU_KTHREAD
static void z_erofs_decompressqueue_kthread_work(struct kthread_work *work)
{
z_erofs_decompressqueue_work((struct work_struct *)work);
}
#endif
static void z_erofs_decompress_kickoff(struct z_erofs_decompressqueue *io,
int bios)
{
struct erofs_sb_info *const sbi = EROFS_SB(io->sb);
/* wake up the caller thread for sync decompression */
if (io->sync) {
if (!atomic_add_return(bios, &io->pending_bios))
complete(&io->u.done);
return;
}
if (atomic_add_return(bios, &io->pending_bios))
return;
/* Use (kthread_)work and sync decompression for atomic contexts only */
if (!in_task() || irqs_disabled() || rcu_read_lock_any_held()) {
#ifdef CONFIG_EROFS_FS_PCPU_KTHREAD
struct kthread_worker *worker;
rcu_read_lock();
worker = rcu_dereference(
z_erofs_pcpu_workers[raw_smp_processor_id()]);
if (!worker) {
INIT_WORK(&io->u.work, z_erofs_decompressqueue_work);
queue_work(z_erofs_workqueue, &io->u.work);
} else {
kthread_queue_work(worker, &io->u.kthread_work);
}
rcu_read_unlock();
#else
queue_work(z_erofs_workqueue, &io->u.work);
#endif
/* 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 void z_erofs_fill_bio_vec(struct bio_vec *bvec,
struct z_erofs_decompress_frontend *f,
struct z_erofs_pcluster *pcl,
unsigned int nr,
struct address_space *mc)
{
gfp_t gfp = mapping_gfp_mask(mc);
bool tocache = false;
struct z_erofs_bvec zbv;
struct address_space *mapping;
struct folio *folio;
struct page *page;
int bs = i_blocksize(f->inode);
/* Except for inplace folios, the entire folio can be used for I/Os */
bvec->bv_offset = 0;
bvec->bv_len = PAGE_SIZE;
repeat:
spin_lock(&pcl->obj.lockref.lock);
zbv = pcl->compressed_bvecs[nr];
spin_unlock(&pcl->obj.lockref.lock);
if (!zbv.page)
goto out_allocfolio;
bvec->bv_page = zbv.page;
DBG_BUGON(z_erofs_is_shortlived_page(bvec->bv_page));
folio = page_folio(zbv.page);
/*
* Handle preallocated cached folios. We tried to allocate such folios
* without triggering direct reclaim. If allocation failed, inplace
* file-backed folios will be used instead.
*/
if (folio->private == (void *)Z_EROFS_PREALLOCATED_PAGE) {
tocache = true;
goto out_tocache;
}
mapping = READ_ONCE(folio->mapping);
/*
* File-backed folios for inplace I/Os are all locked steady,
* therefore it is impossible for `mapping` to be NULL.
*/
if (mapping && mapping != mc) {
if (zbv.offset < 0)
bvec->bv_offset = round_up(-zbv.offset, bs);
bvec->bv_len = round_up(zbv.end, bs) - bvec->bv_offset;
return;
}
folio_lock(folio);
if (likely(folio->mapping == mc)) {
/*
* The cached folio is still in managed cache but without
* a valid `->private` pcluster hint. Let's reconnect them.
*/
if (!folio_test_private(folio)) {
folio_attach_private(folio, pcl);
/* compressed_bvecs[] already takes a ref before */
folio_put(folio);
}
if (likely(folio->private == pcl)) {
/* don't submit cache I/Os again if already uptodate */
if (folio_test_uptodate(folio)) {
folio_unlock(folio);
bvec->bv_page = NULL;
}
return;
}
/*
* Already linked with another pcluster, which only appears in
* crafted images by fuzzers for now. But handle this anyway.
*/
tocache = false; /* use temporary short-lived pages */
} else {
DBG_BUGON(1); /* referenced managed folios can't be truncated */
tocache = true;
}
folio_unlock(folio);
folio_put(folio);
out_allocfolio:
page = __erofs_allocpage(&f->pagepool, gfp, true);
spin_lock(&pcl->obj.lockref.lock);
if (unlikely(pcl->compressed_bvecs[nr].page != zbv.page)) {
if (page)
erofs_pagepool_add(&f->pagepool, page);
spin_unlock(&pcl->obj.lockref.lock);
cond_resched();
goto repeat;
}
pcl->compressed_bvecs[nr].page = page ? page : ERR_PTR(-ENOMEM);
spin_unlock(&pcl->obj.lockref.lock);
bvec->bv_page = page;
if (!page)
return;
folio = page_folio(page);
out_tocache:
if (!tocache || bs != PAGE_SIZE ||
filemap_add_folio(mc, folio, pcl->obj.index + nr, gfp)) {
/* turn into a temporary shortlived folio (1 ref) */
folio->private = (void *)Z_EROFS_SHORTLIVED_PAGE;
return;
}
folio_attach_private(folio, pcl);
/* drop a refcount added by allocpage (then 2 refs in total here) */
folio_put(folio);
}
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;
}
#ifdef CONFIG_EROFS_FS_PCPU_KTHREAD
kthread_init_work(&q->u.kthread_work,
z_erofs_decompressqueue_kthread_work);
#else
INIT_WORK(&q->u.work, z_erofs_decompressqueue_work);
#endif
} else {
fg_out:
q = fgq;
init_completion(&fgq->u.done);
atomic_set(&fgq->pending_bios, 0);
q->eio = false;
q->sync = true;
}
q->sb = sb;
q->head = Z_EROFS_PCLUSTER_TAIL;
return q;
}
/* define decompression jobqueue types */
enum {
JQ_BYPASS,
JQ_SUBMIT,
NR_JOBQUEUES,
};
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];
WRITE_ONCE(pcl->next, Z_EROFS_PCLUSTER_TAIL);
WRITE_ONCE(*submit_qtail, owned_head);
WRITE_ONCE(*bypass_qtail, &pcl->next);
qtail[JQ_BYPASS] = &pcl->next;
}
static void z_erofs_endio(struct bio *bio)
{
struct z_erofs_decompressqueue *q = bio->bi_private;
blk_status_t err = bio->bi_status;
struct folio_iter fi;
bio_for_each_folio_all(fi, bio) {
struct folio *folio = fi.folio;
DBG_BUGON(folio_test_uptodate(folio));
DBG_BUGON(z_erofs_page_is_invalidated(&folio->page));
if (!erofs_folio_is_managed(EROFS_SB(q->sb), folio))
continue;
if (!err)
folio_mark_uptodate(folio);
folio_unlock(folio);
}
if (err)
q->eio = true;
z_erofs_decompress_kickoff(q, -1);
if (bio->bi_bdev)
bio_put(bio);
}
static void z_erofs_submit_queue(struct z_erofs_decompress_frontend *f,
struct z_erofs_decompressqueue *fgq,
bool *force_fg, bool readahead)
{
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];
z_erofs_next_pcluster_t owned_head = f->owned_head;
/* bio is NULL initially, so no need to initialize last_{index,bdev} */
erofs_off_t last_pa;
unsigned int nr_bios = 0;
struct bio *bio = NULL;
unsigned long pflags;
int memstall = 0;
/* No need to read from device for pclusters in the bypass queue. */
q[JQ_BYPASS] = jobqueue_init(sb, fgq + JQ_BYPASS, NULL);
q[JQ_SUBMIT] = jobqueue_init(sb, fgq + JQ_SUBMIT, 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;
erofs_off_t cur, end;
struct bio_vec bvec;
unsigned int i = 0;
bool bypass = true;
DBG_BUGON(owned_head == Z_EROFS_PCLUSTER_NIL);
pcl = container_of(owned_head, struct z_erofs_pcluster, next);
owned_head = READ_ONCE(pcl->next);
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 = erofs_pos(sb, pcl->obj.index),
};
(void)erofs_map_dev(sb, &mdev);
cur = mdev.m_pa;
end = cur + pcl->pclustersize;
do {
bvec.bv_page = NULL;
if (bio && (cur != last_pa ||
bio->bi_bdev != mdev.m_bdev)) {
drain_io:
if (erofs_is_fileio_mode(EROFS_SB(sb)))
erofs_fileio_submit_bio(bio);
else if (erofs_is_fscache_mode(sb))
erofs_fscache_submit_bio(bio);
else
submit_bio(bio);
if (memstall) {
psi_memstall_leave(&pflags);
memstall = 0;
}
bio = NULL;
}
if (!bvec.bv_page) {
z_erofs_fill_bio_vec(&bvec, f, pcl, i++, mc);
if (!bvec.bv_page)
continue;
if (cur + bvec.bv_len > end)
bvec.bv_len = end - cur;
DBG_BUGON(bvec.bv_len < sb->s_blocksize);
}
if (unlikely(PageWorkingset(bvec.bv_page)) &&
!memstall) {
psi_memstall_enter(&pflags);
memstall = 1;
}
if (!bio) {
if (erofs_is_fileio_mode(EROFS_SB(sb)))
bio = erofs_fileio_bio_alloc(&mdev);
else if (erofs_is_fscache_mode(sb))
bio = erofs_fscache_bio_alloc(&mdev);
else
bio = bio_alloc(mdev.m_bdev, BIO_MAX_VECS,
REQ_OP_READ, GFP_NOIO);
bio->bi_end_io = z_erofs_endio;
bio->bi_iter.bi_sector = cur >> 9;
bio->bi_private = q[JQ_SUBMIT];
if (readahead)
bio->bi_opf |= REQ_RAHEAD;
++nr_bios;
}
if (!bio_add_page(bio, bvec.bv_page, bvec.bv_len,
bvec.bv_offset))
goto drain_io;
last_pa = cur + bvec.bv_len;
bypass = false;
} while ((cur += bvec.bv_len) < 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) {
if (erofs_is_fileio_mode(EROFS_SB(sb)))
erofs_fileio_submit_bio(bio);
else if (erofs_is_fscache_mode(sb))
erofs_fscache_submit_bio(bio);
else
submit_bio(bio);
if (memstall)
psi_memstall_leave(&pflags);
}
/*
* although background is preferred, no one is pending for submission.
* don't issue decompression but drop it directly instead.
*/
if (!*force_fg && !nr_bios) {
kvfree(q[JQ_SUBMIT]);
return;
}
z_erofs_decompress_kickoff(q[JQ_SUBMIT], nr_bios);
}
static int z_erofs_runqueue(struct z_erofs_decompress_frontend *f,
unsigned int ra_folios)
{
struct z_erofs_decompressqueue io[NR_JOBQUEUES];
struct erofs_sb_info *sbi = EROFS_I_SB(f->inode);
bool force_fg = z_erofs_is_sync_decompress(sbi, ra_folios);
int err;
if (f->owned_head == Z_EROFS_PCLUSTER_TAIL)
return 0;
z_erofs_submit_queue(f, io, &force_fg, !!ra_folios);
/* handle bypass queue (no i/o pclusters) immediately */
err = z_erofs_decompress_queue(&io[JQ_BYPASS], &f->pagepool);
if (!force_fg)
return err;
/* wait until all bios are completed */
wait_for_completion_io(&io[JQ_SUBMIT].u.done);
/* handle synchronous decompress queue in the caller context */
return z_erofs_decompress_queue(&io[JQ_SUBMIT], &f->pagepool) ?: err;
}
/*
* 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, bool backmost)
{
struct inode *inode = f->inode;
struct erofs_map_blocks *map = &f->map;
erofs_off_t cur, end, headoffset = f->headoffset;
int err;
if (backmost) {
if (rac)
end = headoffset + readahead_length(rac) - 1;
else
end = headoffset + PAGE_SIZE - 1;
map->m_la = end;
err = z_erofs_map_blocks_iter(inode, map,
EROFS_GET_BLOCKS_READMORE);
if (err)
return;
/* expand ra for the trailing edge if readahead */
if (rac) {
cur = round_up(map->m_la + map->m_llen, PAGE_SIZE);
readahead_expand(rac, headoffset, cur - headoffset);
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) && (cur < i_size_read(inode))) {
pgoff_t index = cur >> PAGE_SHIFT;
struct folio *folio;
folio = erofs_grab_folio_nowait(inode->i_mapping, index);
if (!IS_ERR_OR_NULL(folio)) {
if (folio_test_uptodate(folio))
folio_unlock(folio);
else
z_erofs_scan_folio(f, folio, !!rac);
folio_put(folio);
}
if (cur < PAGE_SIZE)
break;
cur = (index << PAGE_SHIFT) - 1;
}
}
static int z_erofs_read_folio(struct file *file, struct folio *folio)
{
struct inode *const inode = folio->mapping->host;
struct z_erofs_decompress_frontend f = DECOMPRESS_FRONTEND_INIT(inode);
int err;
trace_erofs_read_folio(folio, false);
f.headoffset = (erofs_off_t)folio->index << PAGE_SHIFT;
z_erofs_pcluster_readmore(&f, NULL, true);
err = z_erofs_scan_folio(&f, folio, false);
z_erofs_pcluster_readmore(&f, NULL, false);
z_erofs_pcluster_end(&f);
/* if some pclusters are ready, need submit them anyway */
err = z_erofs_runqueue(&f, 0) ?: err;
if (err && err != -EINTR)
erofs_err(inode->i_sb, "read error %d @ %lu of nid %llu",
err, folio->index, EROFS_I(inode)->nid);
erofs_put_metabuf(&f.map.buf);
erofs_release_pages(&f.pagepool);
return err;
}
static void z_erofs_readahead(struct readahead_control *rac)
{
struct inode *const inode = rac->mapping->host;
struct z_erofs_decompress_frontend f = DECOMPRESS_FRONTEND_INIT(inode);
struct folio *head = NULL, *folio;
unsigned int nr_folios;
int err;
f.headoffset = readahead_pos(rac);
z_erofs_pcluster_readmore(&f, rac, true);
nr_folios = readahead_count(rac);
trace_erofs_readpages(inode, readahead_index(rac), nr_folios, false);
while ((folio = readahead_folio(rac))) {
folio->private = head;
head = folio;
}
/* traverse in reverse order for best metadata I/O performance */
while (head) {
folio = head;
head = folio_get_private(folio);
err = z_erofs_scan_folio(&f, folio, true);
if (err && err != -EINTR)
erofs_err(inode->i_sb, "readahead error at folio %lu @ nid %llu",
folio->index, EROFS_I(inode)->nid);
}
z_erofs_pcluster_readmore(&f, rac, false);
z_erofs_pcluster_end(&f);
(void)z_erofs_runqueue(&f, nr_folios);
erofs_put_metabuf(&f.map.buf);
erofs_release_pages(&f.pagepool);
}
const struct address_space_operations z_erofs_aops = {
.read_folio = z_erofs_read_folio,
.readahead = z_erofs_readahead,
};
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