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zdata.c
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// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2018 HUAWEI, Inc.
* https://www.huawei.com/
* 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: 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;
};
union {
/* I: physical cluster size in pages */
unsigned short pclusterpages;
/* I: tailpacking inline compressed size */
unsigned short tailpacking_size;
};
/* I: compression algorithm format */
unsigned char algorithmformat;
/* L: whether partial decompression or not */
bool partial;
/* L: indicate several pageofs_outs or not */
bool multibases;
/* 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)
{
if (z_erofs_is_inline_pcluster(pcl))
return 1;
return pcl->pclusterpages;
}
/*
* bit 30: I/O error occurred on this page
* bit 0 - 29: remaining parts to complete this page
*/
#define Z_EROFS_PAGE_EIO (1 << 30)
static inline void z_erofs_onlinepage_init(struct page *page)
{
union {
atomic_t o;
unsigned long v;
} u = { .o = ATOMIC_INIT(1) };
set_page_private(page, u.v);
smp_wmb();
SetPagePrivate(page);
}
static inline void z_erofs_onlinepage_split(struct page *page)
{
atomic_inc((atomic_t *)&page->private);
}
static void z_erofs_onlinepage_endio(struct page *page, int err)
{
int orig, v;
DBG_BUGON(!PagePrivate(page));
do {
orig = atomic_read((atomic_t *)&page->private);
v = (orig - 1) | (err ? Z_EROFS_PAGE_EIO : 0);
} while (atomic_cmpxchg((atomic_t *)&page->private, orig, v) != orig);
if (!(v & ~Z_EROFS_PAGE_EIO)) {
set_page_private(page, 0);
ClearPagePrivate(page);
if (!(v & Z_EROFS_PAGE_EIO))
SetPageUptodate(page);
unlock_page(page);
}
}
#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_NOFS);
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 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);
}
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_zip_subsystem(void)
{
erofs_cpu_hotplug_destroy();
erofs_destroy_percpu_workers();
destroy_workqueue(z_erofs_workqueue);
z_erofs_destroy_pcluster_pool();
}
int __init z_erofs_init_zip_subsystem(void)
{
int err = z_erofs_create_pcluster_pool();
if (err)
goto out_error_pcluster_pool;
z_erofs_workqueue = alloc_workqueue("erofs_worker",
WQ_UNBOUND | WQ_HIGHPRI, num_possible_cpus());
if (!z_erofs_workqueue) {
err = -ENOMEM;
goto out_error_workqueue_init;
}
err = erofs_init_percpu_workers();
if (err)
goto out_error_pcpu_worker;
err = erofs_cpu_hotplug_init();
if (err < 0)
goto out_error_cpuhp_init;
return err;
out_error_cpuhp_init:
erofs_destroy_percpu_workers();
out_error_pcpu_worker:
destroy_workqueue(z_erofs_workqueue);
out_error_workqueue_init:
z_erofs_destroy_pcluster_pool();
out_error_pcluster_pool:
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;
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 (fe->mode < Z_EROFS_PCLUSTER_FOLLOWED)
return;
for (i = 0; i < pcl->pclusterpages; ++i) {
struct page *page;
void *t; /* mark pages just found for debugging */
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 = (void *)((unsigned long)page | 1);
} else {
/* I/O is needed, no possible to decompress directly */
standalone = false;
if (!shouldalloc)
continue;
/*
* try to use cached I/O if page 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);
t = (void *)((unsigned long)newpage | 1);
}
if (!cmpxchg_relaxed(&pcl->compressed_bvecs[i].page, NULL, t))
continue;
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;
}
/* 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 0,
* 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;
}
static bool z_erofs_cache_release_folio(struct folio *folio, gfp_t gfp)
{
struct z_erofs_pcluster *pcl = folio_get_private(folio);
bool ret;
int i;
if (!folio_test_private(folio))
return true;
ret = false;
spin_lock(&pcl->obj.lockref.lock);
if (pcl->obj.lockref.count > 0)
goto out;
DBG_BUGON(z_erofs_is_inline_pcluster(pcl));
for (i = 0; i < pcl->pclusterpages; ++i) {
if (pcl->compressed_bvecs[i].page == &folio->page) {
WRITE_ONCE(pcl->compressed_bvecs[i].page, NULL);
ret = true;
break;
}
}
if (ret)
folio_detach_private(folio);
out:
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, GFP_NOFS))
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_NOFS);
EROFS_SB(sb)->managed_cache = inode;
return 0;
}
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->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;
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 && !(map->m_pa >> PAGE_SHIFT))) {
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);
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 */
pcl->pageofs_in = erofs_blkoff(fe->inode->i_sb, 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;
}
}
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, blknr, 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->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 page *page,
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.inode = packed_inode;
for (; cur < end; cur += cnt, pos += cnt) {
cnt = min_t(unsigned int, end - cur,
sb->s_blocksize - erofs_blkoff(sb, pos));
src = erofs_bread(&buf, erofs_blknr(sb, pos), EROFS_KMAP);
if (IS_ERR(src)) {
erofs_put_metabuf(&buf);
return PTR_ERR(src);
}
memcpy_to_page(page, cur, src + erofs_blkoff(sb, pos), cnt);
}
erofs_put_metabuf(&buf);
return 0;
}
static int z_erofs_do_read_page(struct z_erofs_decompress_frontend *fe,
struct page *page)
{
struct inode *const inode = fe->inode;
struct erofs_map_blocks *const map = &fe->map;
const loff_t offset = page_offset(page);
bool tight = true, exclusive;
unsigned int cur, end, len, split;
int err = 0;
z_erofs_onlinepage_init(page);
split = 0;
end = PAGE_SIZE;
repeat:
if (offset + end - 1 < map->m_la ||
offset + end - 1 >= map->m_la + map->m_llen) {
z_erofs_pcluster_end(fe);
map->m_la = offset + end - 1;
map->m_llen = 0;
err = z_erofs_map_blocks_iter(inode, map, 0);
if (err)
goto out;
}
cur = offset > map->m_la ? 0 : map->m_la - offset;
/* bump split parts first to avoid several separate cases */
++split;
if (!(map->m_flags & EROFS_MAP_MAPPED)) {
zero_user_segment(page, cur, end);