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* GPL HEADER START
*
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 only,
* as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License version 2 for more details (a copy is included
* in the LICENSE file that accompanied this code).
*
* You should have received a copy of the GNU General Public License
* version 2 along with this program; If not, see
* http://www.sun.com/software/products/lustre/docs/GPLv2.pdf
*
* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
* CA 95054 USA or visit www.sun.com if you need additional information or
* have any questions.
*
* GPL HEADER END
*/
/*
* Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
* Use is subject to license terms.
*
* Copyright (c) 2011, 2012, Intel Corporation.
*/
/*
* This file is part of Lustre, http://www.lustre.org/
* Lustre is a trademark of Sun Microsystems, Inc.
*
* Client Lustre Page.
*
* Author: Nikita Danilov <nikita.danilov@sun.com>
*/
#define DEBUG_SUBSYSTEM S_CLASS
#include <linux/libcfs/libcfs.h>
#include <obd_class.h>
#include <obd_support.h>
#include <linux/list.h>
#include <cl_object.h>
#include "cl_internal.h"
static void cl_page_delete0(const struct lu_env *env, struct cl_page *pg,
int radix);
# define PASSERT(env, page, expr) \
do { \
if (unlikely(!(expr))) { \
CL_PAGE_DEBUG(D_ERROR, (env), (page), #expr "\n"); \
LASSERT(0); \
} \
} while (0)
# define PINVRNT(env, page, exp) \
((void)sizeof(env), (void)sizeof(page), (void)sizeof !!(exp))
/* Disable page statistic by default due to huge performance penalty. */
#define CS_PAGE_INC(o, item)
#define CS_PAGE_DEC(o, item)
#define CS_PAGESTATE_INC(o, state)
#define CS_PAGESTATE_DEC(o, state)
/**
* Internal version of cl_page_top, it should be called if the page is
* known to be not freed, says with page referenced, or radix tree lock held,
* or page owned.
*/
static struct cl_page *cl_page_top_trusted(struct cl_page *page)
{
while (page->cp_parent != NULL)
page = page->cp_parent;
return page;
}
/**
* Internal version of cl_page_get().
*
* This function can be used to obtain initial reference to previously
* unreferenced cached object. It can be called only if concurrent page
* reclamation is somehow prevented, e.g., by locking page radix-tree
* (cl_object_header::hdr->coh_page_guard), or by keeping a lock on a VM page,
* associated with \a page.
*
* Use with care! Not exported.
*/
static void cl_page_get_trust(struct cl_page *page)
{
LASSERT(atomic_read(&page->cp_ref) > 0);
atomic_inc(&page->cp_ref);
}
/**
* Returns a slice within a page, corresponding to the given layer in the
* device stack.
*
* \see cl_lock_at()
*/
static const struct cl_page_slice *
cl_page_at_trusted(const struct cl_page *page,
const struct lu_device_type *dtype)
{
const struct cl_page_slice *slice;
page = cl_page_top_trusted((struct cl_page *)page);
do {
list_for_each_entry(slice, &page->cp_layers, cpl_linkage) {
if (slice->cpl_obj->co_lu.lo_dev->ld_type == dtype)
return slice;
}
page = page->cp_child;
} while (page != NULL);
return NULL;
}
/**
* Returns a page with given index in the given object, or NULL if no page is
* found. Acquires a reference on \a page.
*
* Locking: called under cl_object_header::coh_page_guard spin-lock.
*/
struct cl_page *cl_page_lookup(struct cl_object_header *hdr, pgoff_t index)
{
struct cl_page *page;
LASSERT(spin_is_locked(&hdr->coh_page_guard));
page = radix_tree_lookup(&hdr->coh_tree, index);
if (page != NULL)
cl_page_get_trust(page);
return page;
}
EXPORT_SYMBOL(cl_page_lookup);
/**
* Returns a list of pages by a given [start, end] of \a obj.
*
* \param resched If not NULL, then we give up before hogging CPU for too
* long and set *resched = 1, in that case caller should implement a retry
* logic.
*
* Gang tree lookup (radix_tree_gang_lookup()) optimization is absolutely
* crucial in the face of [offset, EOF] locks.
*
* Return at least one page in @queue unless there is no covered page.
*/
int cl_page_gang_lookup(const struct lu_env *env, struct cl_object *obj,
struct cl_io *io, pgoff_t start, pgoff_t end,
cl_page_gang_cb_t cb, void *cbdata)
{
struct cl_object_header *hdr;
struct cl_page *page;
struct cl_page **pvec;
const struct cl_page_slice *slice;
const struct lu_device_type *dtype;
pgoff_t idx;
unsigned int nr;
unsigned int i;
unsigned int j;
int res = CLP_GANG_OKAY;
int tree_lock = 1;
idx = start;
hdr = cl_object_header(obj);
pvec = cl_env_info(env)->clt_pvec;
dtype = cl_object_top(obj)->co_lu.lo_dev->ld_type;
spin_lock(&hdr->coh_page_guard);
while ((nr = radix_tree_gang_lookup(&hdr->coh_tree, (void **)pvec,
idx, CLT_PVEC_SIZE)) > 0) {
int end_of_region = 0;
idx = pvec[nr - 1]->cp_index + 1;
for (i = 0, j = 0; i < nr; ++i) {
page = pvec[i];
pvec[i] = NULL;
LASSERT(page->cp_type == CPT_CACHEABLE);
if (page->cp_index > end) {
end_of_region = 1;
break;
}
if (page->cp_state == CPS_FREEING)
continue;
slice = cl_page_at_trusted(page, dtype);
/*
* Pages for lsm-less file has no underneath sub-page
* for osc, in case of ...
*/
PASSERT(env, page, slice != NULL);
page = slice->cpl_page;
/*
* Can safely call cl_page_get_trust() under
* radix-tree spin-lock.
*
* XXX not true, because @page is from object another
* than @hdr and protected by different tree lock.
*/
cl_page_get_trust(page);
lu_ref_add_atomic(&page->cp_reference,
"gang_lookup", current);
pvec[j++] = page;
}
/*
* Here a delicate locking dance is performed. Current thread
* holds a reference to a page, but has to own it before it
* can be placed into queue. Owning implies waiting, so
* radix-tree lock is to be released. After a wait one has to
* check that pages weren't truncated (cl_page_own() returns
* error in the latter case).
*/
spin_unlock(&hdr->coh_page_guard);
tree_lock = 0;
for (i = 0; i < j; ++i) {
page = pvec[i];
if (res == CLP_GANG_OKAY)
res = (*cb)(env, io, page, cbdata);
lu_ref_del(&page->cp_reference,
"gang_lookup", current);
cl_page_put(env, page);
}
if (nr < CLT_PVEC_SIZE || end_of_region)
break;
if (res == CLP_GANG_OKAY && need_resched())
res = CLP_GANG_RESCHED;
if (res != CLP_GANG_OKAY)
break;
spin_lock(&hdr->coh_page_guard);
tree_lock = 1;
}
if (tree_lock)
spin_unlock(&hdr->coh_page_guard);
return res;
}
EXPORT_SYMBOL(cl_page_gang_lookup);
static void cl_page_free(const struct lu_env *env, struct cl_page *page)
{
struct cl_object *obj = page->cp_obj;
int pagesize = cl_object_header(obj)->coh_page_bufsize;
PASSERT(env, page, list_empty(&page->cp_batch));
PASSERT(env, page, page->cp_owner == NULL);
PASSERT(env, page, page->cp_req == NULL);
PASSERT(env, page, page->cp_parent == NULL);
PASSERT(env, page, page->cp_state == CPS_FREEING);
might_sleep();
while (!list_empty(&page->cp_layers)) {
struct cl_page_slice *slice;
slice = list_entry(page->cp_layers.next,
struct cl_page_slice, cpl_linkage);
list_del_init(page->cp_layers.next);
slice->cpl_ops->cpo_fini(env, slice);
}
CS_PAGE_DEC(obj, total);
CS_PAGESTATE_DEC(obj, page->cp_state);
lu_object_ref_del_at(&obj->co_lu, &page->cp_obj_ref, "cl_page", page);
cl_object_put(env, obj);
lu_ref_fini(&page->cp_reference);
OBD_FREE(page, pagesize);
}
/**
* Helper function updating page state. This is the only place in the code
* where cl_page::cp_state field is mutated.
*/
static inline void cl_page_state_set_trust(struct cl_page *page,
enum cl_page_state state)
{
/* bypass const. */
*(enum cl_page_state *)&page->cp_state = state;
}
static struct cl_page *cl_page_alloc(const struct lu_env *env,
struct cl_object *o, pgoff_t ind, struct page *vmpage,
enum cl_page_type type)
{
struct cl_page *page;
struct lu_object_header *head;
OBD_ALLOC_GFP(page, cl_object_header(o)->coh_page_bufsize,
__GFP_IO);
if (page != NULL) {
int result = 0;
atomic_set(&page->cp_ref, 1);
if (type == CPT_CACHEABLE) /* for radix tree */
atomic_inc(&page->cp_ref);
page->cp_obj = o;
cl_object_get(o);
lu_object_ref_add_at(&o->co_lu, &page->cp_obj_ref, "cl_page",
page);
page->cp_index = ind;
cl_page_state_set_trust(page, CPS_CACHED);
page->cp_type = type;
INIT_LIST_HEAD(&page->cp_layers);
INIT_LIST_HEAD(&page->cp_batch);
INIT_LIST_HEAD(&page->cp_flight);
mutex_init(&page->cp_mutex);
lu_ref_init(&page->cp_reference);
head = o->co_lu.lo_header;
list_for_each_entry(o, &head->loh_layers,
co_lu.lo_linkage) {
if (o->co_ops->coo_page_init != NULL) {
result = o->co_ops->coo_page_init(env, o,
page, vmpage);
if (result != 0) {
cl_page_delete0(env, page, 0);
cl_page_free(env, page);
page = ERR_PTR(result);
break;
}
}
}
if (result == 0) {
CS_PAGE_INC(o, total);
CS_PAGE_INC(o, create);
CS_PAGESTATE_DEC(o, CPS_CACHED);
}
} else {
page = ERR_PTR(-ENOMEM);
}
return page;
}
/**
* Returns a cl_page with index \a idx at the object \a o, and associated with
* the VM page \a vmpage.
*
* This is the main entry point into the cl_page caching interface. First, a
* cache (implemented as a per-object radix tree) is consulted. If page is
* found there, it is returned immediately. Otherwise new page is allocated
* and returned. In any case, additional reference to page is acquired.
*
* \see cl_object_find(), cl_lock_find()
*/
static struct cl_page *cl_page_find0(const struct lu_env *env,
struct cl_object *o,
pgoff_t idx, struct page *vmpage,
enum cl_page_type type,
struct cl_page *parent)
{
struct cl_page *page = NULL;
struct cl_page *ghost = NULL;
struct cl_object_header *hdr;
int err;
LASSERT(type == CPT_CACHEABLE || type == CPT_TRANSIENT);
might_sleep();
hdr = cl_object_header(o);
CS_PAGE_INC(o, lookup);
CDEBUG(D_PAGE, "%lu@"DFID" %p %lx %d\n",
idx, PFID(&hdr->coh_lu.loh_fid), vmpage, vmpage->private, type);
/* fast path. */
if (type == CPT_CACHEABLE) {
/* vmpage lock is used to protect the child/parent
* relationship */
KLASSERT(PageLocked(vmpage));
/*
* cl_vmpage_page() can be called here without any locks as
*
* - "vmpage" is locked (which prevents ->private from
* concurrent updates), and
*
* - "o" cannot be destroyed while current thread holds a
* reference on it.
*/
page = cl_vmpage_page(vmpage, o);
PINVRNT(env, page,
ergo(page != NULL,
cl_page_vmpage(env, page) == vmpage &&
(void *)radix_tree_lookup(&hdr->coh_tree,
idx) == page));
}
if (page != NULL) {
CS_PAGE_INC(o, hit);
return page;
}
/* allocate and initialize cl_page */
page = cl_page_alloc(env, o, idx, vmpage, type);
if (IS_ERR(page))
return page;
if (type == CPT_TRANSIENT) {
if (parent) {
LASSERT(page->cp_parent == NULL);
page->cp_parent = parent;
parent->cp_child = page;
}
return page;
}
/*
* XXX optimization: use radix_tree_preload() here, and change tree
* gfp mask to GFP_KERNEL in cl_object_header_init().
*/
spin_lock(&hdr->coh_page_guard);
err = radix_tree_insert(&hdr->coh_tree, idx, page);
if (err != 0) {
ghost = page;
/*
* Noted by Jay: a lock on \a vmpage protects cl_page_find()
* from this race, but
*
* 0. it's better to have cl_page interface "locally
* consistent" so that its correctness can be reasoned
* about without appealing to the (obscure world of) VM
* locking.
*
* 1. handling this race allows ->coh_tree to remain
* consistent even when VM locking is somehow busted,
* which is very useful during diagnosing and debugging.
*/
page = ERR_PTR(err);
CL_PAGE_DEBUG(D_ERROR, env, ghost,
"fail to insert into radix tree: %d\n", err);
} else {
if (parent) {
LASSERT(page->cp_parent == NULL);
page->cp_parent = parent;
parent->cp_child = page;
}
hdr->coh_pages++;
}
spin_unlock(&hdr->coh_page_guard);
if (unlikely(ghost != NULL)) {
cl_page_delete0(env, ghost, 0);
cl_page_free(env, ghost);
}
return page;
}
struct cl_page *cl_page_find(const struct lu_env *env, struct cl_object *o,
pgoff_t idx, struct page *vmpage,
enum cl_page_type type)
{
return cl_page_find0(env, o, idx, vmpage, type, NULL);
}
EXPORT_SYMBOL(cl_page_find);
struct cl_page *cl_page_find_sub(const struct lu_env *env, struct cl_object *o,
pgoff_t idx, struct page *vmpage,
struct cl_page *parent)
{
return cl_page_find0(env, o, idx, vmpage, parent->cp_type, parent);
}
EXPORT_SYMBOL(cl_page_find_sub);
static inline int cl_page_invariant(const struct cl_page *pg)
{
struct cl_object_header *header;
struct cl_page *parent;
struct cl_page *child;
struct cl_io *owner;
/*
* Page invariant is protected by a VM lock.
*/
LINVRNT(cl_page_is_vmlocked(NULL, pg));
header = cl_object_header(pg->cp_obj);
parent = pg->cp_parent;
child = pg->cp_child;
owner = pg->cp_owner;
return cl_page_in_use(pg) &&
ergo(parent != NULL, parent->cp_child == pg) &&
ergo(child != NULL, child->cp_parent == pg) &&
ergo(child != NULL, pg->cp_obj != child->cp_obj) &&
ergo(parent != NULL, pg->cp_obj != parent->cp_obj) &&
ergo(owner != NULL && parent != NULL,
parent->cp_owner == pg->cp_owner->ci_parent) &&
ergo(owner != NULL && child != NULL,
child->cp_owner->ci_parent == owner) &&
/*
* Either page is early in initialization (has neither child
* nor parent yet), or it is in the object radix tree.
*/
ergo(pg->cp_state < CPS_FREEING && pg->cp_type == CPT_CACHEABLE,
(void *)radix_tree_lookup(&header->coh_tree,
pg->cp_index) == pg ||
(child == NULL && parent == NULL));
}
static void cl_page_state_set0(const struct lu_env *env,
struct cl_page *page, enum cl_page_state state)
{
enum cl_page_state old;
/*
* Matrix of allowed state transitions [old][new], for sanity
* checking.
*/
static const int allowed_transitions[CPS_NR][CPS_NR] = {
[CPS_CACHED] = {
[CPS_CACHED] = 0,
[CPS_OWNED] = 1, /* io finds existing cached page */
[CPS_PAGEIN] = 0,
[CPS_PAGEOUT] = 1, /* write-out from the cache */
[CPS_FREEING] = 1, /* eviction on the memory pressure */
},
[CPS_OWNED] = {
[CPS_CACHED] = 1, /* release to the cache */
[CPS_OWNED] = 0,
[CPS_PAGEIN] = 1, /* start read immediately */
[CPS_PAGEOUT] = 1, /* start write immediately */
[CPS_FREEING] = 1, /* lock invalidation or truncate */
},
[CPS_PAGEIN] = {
[CPS_CACHED] = 1, /* io completion */
[CPS_OWNED] = 0,
[CPS_PAGEIN] = 0,
[CPS_PAGEOUT] = 0,
[CPS_FREEING] = 0,
},
[CPS_PAGEOUT] = {
[CPS_CACHED] = 1, /* io completion */
[CPS_OWNED] = 0,
[CPS_PAGEIN] = 0,
[CPS_PAGEOUT] = 0,
[CPS_FREEING] = 0,
},
[CPS_FREEING] = {
[CPS_CACHED] = 0,
[CPS_OWNED] = 0,
[CPS_PAGEIN] = 0,
[CPS_PAGEOUT] = 0,
[CPS_FREEING] = 0,
}
};
old = page->cp_state;
PASSERT(env, page, allowed_transitions[old][state]);
CL_PAGE_HEADER(D_TRACE, env, page, "%d -> %d\n", old, state);
for (; page != NULL; page = page->cp_child) {
PASSERT(env, page, page->cp_state == old);
PASSERT(env, page,
equi(state == CPS_OWNED, page->cp_owner != NULL));
CS_PAGESTATE_DEC(page->cp_obj, page->cp_state);
CS_PAGESTATE_INC(page->cp_obj, state);
cl_page_state_set_trust(page, state);
}
}
static void cl_page_state_set(const struct lu_env *env,
struct cl_page *page, enum cl_page_state state)
{
cl_page_state_set0(env, page, state);
}
/**
* Acquires an additional reference to a page.
*
* This can be called only by caller already possessing a reference to \a
* page.
*
* \see cl_object_get(), cl_lock_get().
*/
void cl_page_get(struct cl_page *page)
{
cl_page_get_trust(page);
}
EXPORT_SYMBOL(cl_page_get);
/**
* Releases a reference to a page.
*
* When last reference is released, page is returned to the cache, unless it
* is in cl_page_state::CPS_FREEING state, in which case it is immediately
* destroyed.
*
* \see cl_object_put(), cl_lock_put().
*/
void cl_page_put(const struct lu_env *env, struct cl_page *page)
{
PASSERT(env, page, atomic_read(&page->cp_ref) > !!page->cp_parent);
CL_PAGE_HEADER(D_TRACE, env, page, "%d\n",
atomic_read(&page->cp_ref));
if (atomic_dec_and_test(&page->cp_ref)) {
LASSERT(page->cp_state == CPS_FREEING);
LASSERT(atomic_read(&page->cp_ref) == 0);
PASSERT(env, page, page->cp_owner == NULL);
PASSERT(env, page, list_empty(&page->cp_batch));
/*
* Page is no longer reachable by other threads. Tear
* it down.
*/
cl_page_free(env, page);
}
}
EXPORT_SYMBOL(cl_page_put);
/**
* Returns a VM page associated with a given cl_page.
*/
struct page *cl_page_vmpage(const struct lu_env *env, struct cl_page *page)
{
const struct cl_page_slice *slice;
/*
* Find uppermost layer with ->cpo_vmpage() method, and return its
* result.
*/
page = cl_page_top(page);
do {
list_for_each_entry(slice, &page->cp_layers, cpl_linkage) {
if (slice->cpl_ops->cpo_vmpage != NULL)
return slice->cpl_ops->cpo_vmpage(env, slice);
}
page = page->cp_child;
} while (page != NULL);
LBUG(); /* ->cpo_vmpage() has to be defined somewhere in the stack */
}
EXPORT_SYMBOL(cl_page_vmpage);
/**
* Returns a cl_page associated with a VM page, and given cl_object.
*/
struct cl_page *cl_vmpage_page(struct page *vmpage, struct cl_object *obj)
{
struct cl_page *top;
struct cl_page *page;
KLASSERT(PageLocked(vmpage));
/*
* NOTE: absence of races and liveness of data are guaranteed by page
* lock on a "vmpage". That works because object destruction has
* bottom-to-top pass.
*/
/*
* This loop assumes that ->private points to the top-most page. This
* can be rectified easily.
*/
top = (struct cl_page *)vmpage->private;
if (top == NULL)
return NULL;
for (page = top; page != NULL; page = page->cp_child) {
if (cl_object_same(page->cp_obj, obj)) {
cl_page_get_trust(page);
break;
}
}
LASSERT(ergo(page, page->cp_type == CPT_CACHEABLE));
return page;
}
EXPORT_SYMBOL(cl_vmpage_page);
/**
* Returns the top-page for a given page.
*
* \see cl_object_top(), cl_io_top()
*/
struct cl_page *cl_page_top(struct cl_page *page)
{
return cl_page_top_trusted(page);
}
EXPORT_SYMBOL(cl_page_top);
const struct cl_page_slice *cl_page_at(const struct cl_page *page,
const struct lu_device_type *dtype)
{
return cl_page_at_trusted(page, dtype);
}
EXPORT_SYMBOL(cl_page_at);
#define CL_PAGE_OP(opname) offsetof(struct cl_page_operations, opname)
#define CL_PAGE_INVOKE(_env, _page, _op, _proto, ...) \
({ \
const struct lu_env *__env = (_env); \
struct cl_page *__page = (_page); \
const struct cl_page_slice *__scan; \
int __result; \
ptrdiff_t __op = (_op); \
int (*__method)_proto; \
\
__result = 0; \
__page = cl_page_top(__page); \
do { \
list_for_each_entry(__scan, &__page->cp_layers, \
cpl_linkage) { \
__method = *(void **)((char *)__scan->cpl_ops + \
__op); \
if (__method != NULL) { \
__result = (*__method)(__env, __scan, \
## __VA_ARGS__); \
if (__result != 0) \
break; \
} \
} \
__page = __page->cp_child; \
} while (__page != NULL && __result == 0); \
if (__result > 0) \
__result = 0; \
__result; \
})
#define CL_PAGE_INVOID(_env, _page, _op, _proto, ...) \
do { \
const struct lu_env *__env = (_env); \
struct cl_page *__page = (_page); \
const struct cl_page_slice *__scan; \
ptrdiff_t __op = (_op); \
void (*__method)_proto; \
\
__page = cl_page_top(__page); \
do { \
list_for_each_entry(__scan, &__page->cp_layers, \
cpl_linkage) { \
__method = *(void **)((char *)__scan->cpl_ops + \
__op); \
if (__method != NULL) \
(*__method)(__env, __scan, \
## __VA_ARGS__); \
} \
__page = __page->cp_child; \
} while (__page != NULL); \
} while (0)
#define CL_PAGE_INVOID_REVERSE(_env, _page, _op, _proto, ...) \
do { \
const struct lu_env *__env = (_env); \
struct cl_page *__page = (_page); \
const struct cl_page_slice *__scan; \
ptrdiff_t __op = (_op); \
void (*__method)_proto; \
\
/* get to the bottom page. */ \
while (__page->cp_child != NULL) \
__page = __page->cp_child; \
do { \
list_for_each_entry_reverse(__scan, &__page->cp_layers, \
cpl_linkage) { \
__method = *(void **)((char *)__scan->cpl_ops + \
__op); \
if (__method != NULL) \
(*__method)(__env, __scan, \
## __VA_ARGS__); \
} \
__page = __page->cp_parent; \
} while (__page != NULL); \
} while (0)
static int cl_page_invoke(const struct lu_env *env,
struct cl_io *io, struct cl_page *page, ptrdiff_t op)
{
PINVRNT(env, page, cl_object_same(page->cp_obj, io->ci_obj));
return CL_PAGE_INVOKE(env, page, op,
(const struct lu_env *,
const struct cl_page_slice *, struct cl_io *),
io);
}
static void cl_page_invoid(const struct lu_env *env,
struct cl_io *io, struct cl_page *page, ptrdiff_t op)
{
PINVRNT(env, page, cl_object_same(page->cp_obj, io->ci_obj));
CL_PAGE_INVOID(env, page, op,
(const struct lu_env *,
const struct cl_page_slice *, struct cl_io *), io);
}
static void cl_page_owner_clear(struct cl_page *page)
{
for (page = cl_page_top(page); page != NULL; page = page->cp_child) {
if (page->cp_owner != NULL) {
LASSERT(page->cp_owner->ci_owned_nr > 0);
page->cp_owner->ci_owned_nr--;
page->cp_owner = NULL;
page->cp_task = NULL;
}
}
}
static void cl_page_owner_set(struct cl_page *page)
{
for (page = cl_page_top(page); page != NULL; page = page->cp_child) {
LASSERT(page->cp_owner != NULL);
page->cp_owner->ci_owned_nr++;
}
}
void cl_page_disown0(const struct lu_env *env,
struct cl_io *io, struct cl_page *pg)
{
enum cl_page_state state;
state = pg->cp_state;
PINVRNT(env, pg, state == CPS_OWNED || state == CPS_FREEING);
PINVRNT(env, pg, cl_page_invariant(pg));
cl_page_owner_clear(pg);
if (state == CPS_OWNED)
cl_page_state_set(env, pg, CPS_CACHED);
/*
* Completion call-backs are executed in the bottom-up order, so that
* uppermost layer (llite), responsible for VFS/VM interaction runs
* last and can release locks safely.
*/
CL_PAGE_INVOID_REVERSE(env, pg, CL_PAGE_OP(cpo_disown),
(const struct lu_env *,
const struct cl_page_slice *, struct cl_io *),
io);
}
/**
* returns true, iff page is owned by the given io.
*/
int cl_page_is_owned(const struct cl_page *pg, const struct cl_io *io)
{
LINVRNT(cl_object_same(pg->cp_obj, io->ci_obj));
return pg->cp_state == CPS_OWNED && pg->cp_owner == io;
}
EXPORT_SYMBOL(cl_page_is_owned);
/**
* Try to own a page by IO.
*
* Waits until page is in cl_page_state::CPS_CACHED state, and then switch it
* into cl_page_state::CPS_OWNED state.
*
* \pre !cl_page_is_owned(pg, io)
* \post result == 0 iff cl_page_is_owned(pg, io)
*
* \retval 0 success
*
* \retval -ve failure, e.g., page was destroyed (and landed in
* cl_page_state::CPS_FREEING instead of cl_page_state::CPS_CACHED).
* or, page was owned by another thread, or in IO.
*
* \see cl_page_disown()
* \see cl_page_operations::cpo_own()
* \see cl_page_own_try()
* \see cl_page_own
*/
static int cl_page_own0(const struct lu_env *env, struct cl_io *io,
struct cl_page *pg, int nonblock)
{
int result;
PINVRNT(env, pg, !cl_page_is_owned(pg, io));
pg = cl_page_top(pg);
io = cl_io_top(io);
if (pg->cp_state == CPS_FREEING) {
result = -ENOENT;
} else {
result = CL_PAGE_INVOKE(env, pg, CL_PAGE_OP(cpo_own),
(const struct lu_env *,
const struct cl_page_slice *,
struct cl_io *, int),
io, nonblock);
if (result == 0) {
PASSERT(env, pg, pg->cp_owner == NULL);
PASSERT(env, pg, pg->cp_req == NULL);
pg->cp_owner = io;
pg->cp_task = current;
cl_page_owner_set(pg);
if (pg->cp_state != CPS_FREEING) {
cl_page_state_set(env, pg, CPS_OWNED);
} else {
cl_page_disown0(env, io, pg);
result = -ENOENT;
}
}
}
PINVRNT(env, pg, ergo(result == 0, cl_page_invariant(pg)));
return result;
}
/**
* Own a page, might be blocked.
*
* \see cl_page_own0()
*/
int cl_page_own(const struct lu_env *env, struct cl_io *io, struct cl_page *pg)
{
return cl_page_own0(env, io, pg, 0);
}
EXPORT_SYMBOL(cl_page_own);
/**
* Nonblock version of cl_page_own().
*
* \see cl_page_own0()
*/
int cl_page_own_try(const struct lu_env *env, struct cl_io *io,
struct cl_page *pg)
{
return cl_page_own0(env, io, pg, 1);
}
EXPORT_SYMBOL(cl_page_own_try);
/**
* Assume page ownership.
*
* Called when page is already locked by the hosting VM.
*
* \pre !cl_page_is_owned(pg, io)
* \post cl_page_is_owned(pg, io)
*
* \see cl_page_operations::cpo_assume()
*/
void cl_page_assume(const struct lu_env *env,
struct cl_io *io, struct cl_page *pg)
{
PINVRNT(env, pg, cl_object_same(pg->cp_obj, io->ci_obj));
pg = cl_page_top(pg);
io = cl_io_top(io);
cl_page_invoid(env, io, pg, CL_PAGE_OP(cpo_assume));
PASSERT(env, pg, pg->cp_owner == NULL);
pg->cp_owner = io;
pg->cp_task = current;
cl_page_owner_set(pg);
cl_page_state_set(env, pg, CPS_OWNED);
}
EXPORT_SYMBOL(cl_page_assume);
/**
* Releases page ownership without unlocking the page.
*
* Moves page into cl_page_state::CPS_CACHED without releasing a lock on the
* underlying VM page (as VM is supposed to do this itself).
*
* \pre cl_page_is_owned(pg, io)
* \post !cl_page_is_owned(pg, io)
*
* \see cl_page_assume()
*/
void cl_page_unassume(const struct lu_env *env,
struct cl_io *io, struct cl_page *pg)
{
PINVRNT(env, pg, cl_page_is_owned(pg, io));
PINVRNT(env, pg, cl_page_invariant(pg));
pg = cl_page_top(pg);
io = cl_io_top(io);
cl_page_owner_clear(pg);
cl_page_state_set(env, pg, CPS_CACHED);
CL_PAGE_INVOID_REVERSE(env, pg, CL_PAGE_OP(cpo_unassume),
(const struct lu_env *,
const struct cl_page_slice *, struct cl_io *),
io);
}
EXPORT_SYMBOL(cl_page_unassume);
/**
* Releases page ownership.
*
* Moves page into cl_page_state::CPS_CACHED.
*
* \pre cl_page_is_owned(pg, io)
* \post !cl_page_is_owned(pg, io)
*
* \see cl_page_own()
* \see cl_page_operations::cpo_disown()
*/
void cl_page_disown(const struct lu_env *env,
struct cl_io *io, struct cl_page *pg)
{
PINVRNT(env, pg, cl_page_is_owned(pg, io));
pg = cl_page_top(pg);
io = cl_io_top(io);
cl_page_disown0(env, io, pg);
}
EXPORT_SYMBOL(cl_page_disown);
/**
* Called when page is to be removed from the object, e.g., as a result of
* truncate.
*
* Calls cl_page_operations::cpo_discard() top-to-bottom.
*
* \pre cl_page_is_owned(pg, io)
*
* \see cl_page_operations::cpo_discard()
*/
void cl_page_discard(const struct lu_env *env,
struct cl_io *io, struct cl_page *pg)
{
PINVRNT(env, pg, cl_page_is_owned(pg, io));
PINVRNT(env, pg, cl_page_invariant(pg));
cl_page_invoid(env, io, pg, CL_PAGE_OP(cpo_discard));
}
EXPORT_SYMBOL(cl_page_discard);
/**
* Version of cl_page_delete() that can be called for not fully constructed
* pages, e.g,. in a error handling cl_page_find()->cl_page_delete0()
* path. Doesn't check page invariant.
*/
static void cl_page_delete0(const struct lu_env *env, struct cl_page *pg,
int radix)
{
struct cl_page *tmp = pg;
PASSERT(env, pg, pg == cl_page_top(pg));
PASSERT(env, pg, pg->cp_state != CPS_FREEING);
/*
* Severe all ways to obtain new pointers to @pg.
*/
cl_page_owner_clear(pg);
/*
* unexport the page firstly before freeing it so that
* the page content is considered to be invalid.
* We have to do this because a CPS_FREEING cl_page may
* be NOT under the protection of a cl_lock.
* Afterwards, if this page is found by other threads, then this
* page will be forced to reread.
*/
cl_page_export(env, pg, 0);
cl_page_state_set0(env, pg, CPS_FREEING);
CL_PAGE_INVOID(env, pg, CL_PAGE_OP(cpo_delete),
(const struct lu_env *, const struct cl_page_slice *));
if (tmp->cp_type == CPT_CACHEABLE) {
if (!radix)
/* !radix means that @pg is not yet in the radix tree,
* skip removing it.
*/
tmp = pg->cp_child;
for (; tmp != NULL; tmp = tmp->cp_child) {
void *value;
struct cl_object_header *hdr;
hdr = cl_object_header(tmp->cp_obj);
spin_lock(&hdr->coh_page_guard);
value = radix_tree_delete(&hdr->coh_tree,
tmp->cp_index);
PASSERT(env, tmp, value == tmp);
PASSERT(env, tmp, hdr->coh_pages > 0);
hdr->coh_pages--;
spin_unlock(&hdr->coh_page_guard);
cl_page_put(env, tmp);
}
}
}
/**
* Called when a decision is made to throw page out of memory.
*
* Notifies all layers about page destruction by calling
* cl_page_operations::cpo_delete() method top-to-bottom.
*
* Moves page into cl_page_state::CPS_FREEING state (this is the only place
* where transition to this state happens).
*
* Eliminates all venues through which new references to the page can be
* obtained:
*
* - removes page from the radix trees,
*
* - breaks linkage from VM page to cl_page.
*
* Once page reaches cl_page_state::CPS_FREEING, all remaining references will
* drain after some time, at which point page will be recycled.
*
* \pre pg == cl_page_top(pg)
* \pre VM page is locked
* \post pg->cp_state == CPS_FREEING
*
* \see cl_page_operations::cpo_delete()
*/
void cl_page_delete(const struct lu_env *env, struct cl_page *pg)
{
PINVRNT(env, pg, cl_page_invariant(pg));
cl_page_delete0(env, pg, 1);
}
EXPORT_SYMBOL(cl_page_delete);
/**
* Unmaps page from user virtual memory.
*
* Calls cl_page_operations::cpo_unmap() through all layers top-to-bottom. The
* layer responsible for VM interaction has to unmap page from user space
* virtual memory.
*
* \see cl_page_operations::cpo_unmap()
*/
int cl_page_unmap(const struct lu_env *env,
struct cl_io *io, struct cl_page *pg)
{
PINVRNT(env, pg, cl_page_is_owned(pg, io));
PINVRNT(env, pg, cl_page_invariant(pg));
return cl_page_invoke(env, io, pg, CL_PAGE_OP(cpo_unmap));
}
EXPORT_SYMBOL(cl_page_unmap);
/**
* Marks page up-to-date.
*
* Call cl_page_operations::cpo_export() through all layers top-to-bottom. The
* layer responsible for VM interaction has to mark/clear page as up-to-date
* by the \a uptodate argument.
*
* \see cl_page_operations::cpo_export()
*/
void cl_page_export(const struct lu_env *env, struct cl_page *pg, int uptodate)
{
PINVRNT(env, pg, cl_page_invariant(pg));
CL_PAGE_INVOID(env, pg, CL_PAGE_OP(cpo_export),
(const struct lu_env *,
const struct cl_page_slice *, int), uptodate);
}
EXPORT_SYMBOL(cl_page_export);
/**
* Returns true, iff \a pg is VM locked in a suitable sense by the calling
* thread.
*/
int cl_page_is_vmlocked(const struct lu_env *env, const struct cl_page *pg)
{
int result;
const struct cl_page_slice *slice;
pg = cl_page_top_trusted((struct cl_page *)pg);
slice = container_of(pg->cp_layers.next,
const struct cl_page_slice, cpl_linkage);
PASSERT(env, pg, slice->cpl_ops->cpo_is_vmlocked != NULL);
/*
* Call ->cpo_is_vmlocked() directly instead of going through
* CL_PAGE_INVOKE(), because cl_page_is_vmlocked() is used by
* cl_page_invariant().
*/
result = slice->cpl_ops->cpo_is_vmlocked(env, slice);
PASSERT(env, pg, result == -EBUSY || result == -ENODATA);
return result == -EBUSY;
}
EXPORT_SYMBOL(cl_page_is_vmlocked);
static enum cl_page_state cl_req_type_state(enum cl_req_type crt)
{
return crt == CRT_WRITE ? CPS_PAGEOUT : CPS_PAGEIN;
}
static void cl_page_io_start(const struct lu_env *env,
struct cl_page *pg, enum cl_req_type crt)
{
/*
* Page is queued for IO, change its state.
*/
cl_page_owner_clear(pg);
cl_page_state_set(env, pg, cl_req_type_state(crt));
}
/**
* Prepares page for immediate transfer. cl_page_operations::cpo_prep() is
* called top-to-bottom. Every layer either agrees to submit this page (by
* returning 0), or requests to omit this page (by returning -EALREADY). Layer
* handling interactions with the VM also has to inform VM that page is under
* transfer now.
*/
int cl_page_prep(const struct lu_env *env, struct cl_io *io,
struct cl_page *pg, enum cl_req_type crt)
{
int result;
PINVRNT(env, pg, cl_page_is_owned(pg, io));
PINVRNT(env, pg, cl_page_invariant(pg));
PINVRNT(env, pg, crt < CRT_NR);
/*
* XXX this has to be called bottom-to-top, so that llite can set up
* PG_writeback without risking other layers deciding to skip this
* page.
*/
if (crt >= CRT_NR)
return -EINVAL;
result = cl_page_invoke(env, io, pg, CL_PAGE_OP(io[crt].cpo_prep));
if (result == 0)
cl_page_io_start(env, pg, crt);
KLASSERT(ergo(crt == CRT_WRITE && pg->cp_type == CPT_CACHEABLE,
equi(result == 0,
PageWriteback(cl_page_vmpage(env, pg)))));
CL_PAGE_HEADER(D_TRACE, env, pg, "%d %d\n", crt, result);
return result;
}
EXPORT_SYMBOL(cl_page_prep);
/**
* Notify layers about transfer completion.
*
* Invoked by transfer sub-system (which is a part of osc) to notify layers
* that a transfer, of which this page is a part of has completed.
*
* Completion call-backs are executed in the bottom-up order, so that
* uppermost layer (llite), responsible for the VFS/VM interaction runs last
* and can release locks safely.
*
* \pre pg->cp_state == CPS_PAGEIN || pg->cp_state == CPS_PAGEOUT
* \post pg->cp_state == CPS_CACHED
*
* \see cl_page_operations::cpo_completion()
*/
void cl_page_completion(const struct lu_env *env,
struct cl_page *pg, enum cl_req_type crt, int ioret)
{
struct cl_sync_io *anchor = pg->cp_sync_io;
PASSERT(env, pg, crt < CRT_NR);
/* cl_page::cp_req already cleared by the caller (osc_completion()) */
PASSERT(env, pg, pg->cp_req == NULL);
PASSERT(env, pg, pg->cp_state == cl_req_type_state(crt));
CL_PAGE_HEADER(D_TRACE, env, pg, "%d %d\n", crt, ioret);
if (crt == CRT_READ && ioret == 0) {
PASSERT(env, pg, !(pg->cp_flags & CPF_READ_COMPLETED));
pg->cp_flags |= CPF_READ_COMPLETED;
}
cl_page_state_set(env, pg, CPS_CACHED);
if (crt >= CRT_NR)
return;
CL_PAGE_INVOID_REVERSE(env, pg, CL_PAGE_OP(io[crt].cpo_completion),
(const struct lu_env *,
const struct cl_page_slice *, int), ioret);
if (anchor) {
LASSERT(cl_page_is_vmlocked(env, pg));
LASSERT(pg->cp_sync_io == anchor);
pg->cp_sync_io = NULL;
}
/*
* As page->cp_obj is pinned by a reference from page->cp_req, it is
* safe to call cl_page_put() without risking object destruction in a
* non-blocking context.
*/
cl_page_put(env, pg);
if (anchor)
cl_sync_io_note(anchor, ioret);
}
EXPORT_SYMBOL(cl_page_completion);
/**
* Notify layers that transfer formation engine decided to yank this page from
* the cache and to make it a part of a transfer.
*
* \pre pg->cp_state == CPS_CACHED
* \post pg->cp_state == CPS_PAGEIN || pg->cp_state == CPS_PAGEOUT
*
* \see cl_page_operations::cpo_make_ready()
*/
int cl_page_make_ready(const struct lu_env *env, struct cl_page *pg,
enum cl_req_type crt)
{
int result;
PINVRNT(env, pg, crt < CRT_NR);
if (crt >= CRT_NR)
return -EINVAL;
result = CL_PAGE_INVOKE(env, pg, CL_PAGE_OP(io[crt].cpo_make_ready),
(const struct lu_env *,
const struct cl_page_slice *));
if (result == 0) {
PASSERT(env, pg, pg->cp_state == CPS_CACHED);
cl_page_io_start(env, pg, crt);
}
CL_PAGE_HEADER(D_TRACE, env, pg, "%d %d\n", crt, result);
return result;
}
EXPORT_SYMBOL(cl_page_make_ready);
/**
* Notify layers that high level io decided to place this page into a cache
* for future transfer.
*
* The layer implementing transfer engine (osc) has to register this page in
* its queues.
*
* \pre cl_page_is_owned(pg, io)
* \post cl_page_is_owned(pg, io)
*
* \see cl_page_operations::cpo_cache_add()
*/
int cl_page_cache_add(const struct lu_env *env, struct cl_io *io,
struct cl_page *pg, enum cl_req_type crt)
{
const struct cl_page_slice *scan;
int result = 0;
PINVRNT(env, pg, crt < CRT_NR);
PINVRNT(env, pg, cl_page_is_owned(pg, io));
PINVRNT(env, pg, cl_page_invariant(pg));
if (crt >= CRT_NR)
return -EINVAL;
list_for_each_entry(scan, &pg->cp_layers, cpl_linkage) {
if (scan->cpl_ops->io[crt].cpo_cache_add == NULL)
continue;
result = scan->cpl_ops->io[crt].cpo_cache_add(env, scan, io);
if (result != 0)
break;
}
CL_PAGE_HEADER(D_TRACE, env, pg, "%d %d\n", crt, result);
return result;
}
EXPORT_SYMBOL(cl_page_cache_add);
/**
* Called if a pge is being written back by kernel's intention.
*
* \pre cl_page_is_owned(pg, io)
* \post ergo(result == 0, pg->cp_state == CPS_PAGEOUT)
*
* \see cl_page_operations::cpo_flush()
*/
int cl_page_flush(const struct lu_env *env, struct cl_io *io,
struct cl_page *pg)
{
int result;
PINVRNT(env, pg, cl_page_is_owned(pg, io));
PINVRNT(env, pg, cl_page_invariant(pg));
result = cl_page_invoke(env, io, pg, CL_PAGE_OP(cpo_flush));
CL_PAGE_HEADER(D_TRACE, env, pg, "%d\n", result);
return result;
}
EXPORT_SYMBOL(cl_page_flush);
/**
* Checks whether page is protected by any extent lock is at least required
* mode.
*
* \return the same as in cl_page_operations::cpo_is_under_lock() method.
* \see cl_page_operations::cpo_is_under_lock()
*/
int cl_page_is_under_lock(const struct lu_env *env, struct cl_io *io,
struct cl_page *page)
{
int rc;
PINVRNT(env, page, cl_page_invariant(page));
rc = CL_PAGE_INVOKE(env, page, CL_PAGE_OP(cpo_is_under_lock),
(const struct lu_env *,
const struct cl_page_slice *, struct cl_io *),
io);
PASSERT(env, page, rc != 0);
return rc;
}
EXPORT_SYMBOL(cl_page_is_under_lock);
static int page_prune_cb(const struct lu_env *env, struct cl_io *io,
struct cl_page *page, void *cbdata)
{
cl_page_own(env, io, page);
cl_page_unmap(env, io, page);
cl_page_discard(env, io, page);
cl_page_disown(env, io, page);
return CLP_GANG_OKAY;
}
/**
* Purges all cached pages belonging to the object \a obj.
*/
int cl_pages_prune(const struct lu_env *env, struct cl_object *clobj)
{
struct cl_thread_info *info;
struct cl_object *obj = cl_object_top(clobj);
struct cl_io *io;
int result;
info = cl_env_info(env);
io = &info->clt_io;
/*
* initialize the io. This is ugly since we never do IO in this
* function, we just make cl_page_list functions happy. -jay
*/
io->ci_obj = obj;
io->ci_ignore_layout = 1;
result = cl_io_init(env, io, CIT_MISC, obj);
if (result != 0) {
cl_io_fini(env, io);
return io->ci_result;
}
do {
result = cl_page_gang_lookup(env, obj, io, 0, CL_PAGE_EOF,
page_prune_cb, NULL);
if (result == CLP_GANG_RESCHED)
cond_resched();
} while (result != CLP_GANG_OKAY);
cl_io_fini(env, io);
return result;
}
EXPORT_SYMBOL(cl_pages_prune);
/**
* Tells transfer engine that only part of a page is to be transmitted.
*
* \see cl_page_operations::cpo_clip()
*/
void cl_page_clip(const struct lu_env *env, struct cl_page *pg,
int from, int to)
{
PINVRNT(env, pg, cl_page_invariant(pg));
CL_PAGE_HEADER(D_TRACE, env, pg, "%d %d\n", from, to);
CL_PAGE_INVOID(env, pg, CL_PAGE_OP(cpo_clip),
(const struct lu_env *,
const struct cl_page_slice *,int, int),
from, to);
}
EXPORT_SYMBOL(cl_page_clip);
/**
* Prints human readable representation of \a pg to the \a f.
*/
void cl_page_header_print(const struct lu_env *env, void *cookie,
lu_printer_t printer, const struct cl_page *pg)
{
(*printer)(env, cookie,
"page@%p[%d %p:%lu ^%p_%p %d %d %d %p %p %#x]\n",
pg, atomic_read(&pg->cp_ref), pg->cp_obj,
pg->cp_index, pg->cp_parent, pg->cp_child,
pg->cp_state, pg->cp_error, pg->cp_type,
pg->cp_owner, pg->cp_req, pg->cp_flags);
}
EXPORT_SYMBOL(cl_page_header_print);
/**
* Prints human readable representation of \a pg to the \a f.
*/
void cl_page_print(const struct lu_env *env, void *cookie,
lu_printer_t printer, const struct cl_page *pg)
{
struct cl_page *scan;
for (scan = cl_page_top((struct cl_page *)pg);
scan != NULL; scan = scan->cp_child)
cl_page_header_print(env, cookie, printer, scan);
CL_PAGE_INVOKE(env, (struct cl_page *)pg, CL_PAGE_OP(cpo_print),
(const struct lu_env *env,
const struct cl_page_slice *slice,
void *cookie, lu_printer_t p), cookie, printer);
(*printer)(env, cookie, "end page@%p\n", pg);
}
EXPORT_SYMBOL(cl_page_print);
/**
* Cancel a page which is still in a transfer.
*/
int cl_page_cancel(const struct lu_env *env, struct cl_page *page)
{
return CL_PAGE_INVOKE(env, page, CL_PAGE_OP(cpo_cancel),
(const struct lu_env *,
const struct cl_page_slice *));
}
EXPORT_SYMBOL(cl_page_cancel);
/**
* Converts a byte offset within object \a obj into a page index.
*/
loff_t cl_offset(const struct cl_object *obj, pgoff_t idx)
{
/*
* XXX for now.
*/
return (loff_t)idx << PAGE_CACHE_SHIFT;
}
EXPORT_SYMBOL(cl_offset);
/**
* Converts a page index into a byte offset within object \a obj.
*/
pgoff_t cl_index(const struct cl_object *obj, loff_t offset)
{
/*
* XXX for now.
*/
return offset >> PAGE_CACHE_SHIFT;
}
EXPORT_SYMBOL(cl_index);
int cl_page_size(const struct cl_object *obj)
{
return 1 << PAGE_CACHE_SHIFT;
}
EXPORT_SYMBOL(cl_page_size);
/**
* Adds page slice to the compound page.
*
* This is called by cl_object_operations::coo_page_init() methods to add a
* per-layer state to the page. New state is added at the end of
* cl_page::cp_layers list, that is, it is at the bottom of the stack.
*
* \see cl_lock_slice_add(), cl_req_slice_add(), cl_io_slice_add()
*/
void cl_page_slice_add(struct cl_page *page, struct cl_page_slice *slice,
struct cl_object *obj,
const struct cl_page_operations *ops)
{
list_add_tail(&slice->cpl_linkage, &page->cp_layers);
slice->cpl_obj = obj;
slice->cpl_ops = ops;
slice->cpl_page = page;
}
EXPORT_SYMBOL(cl_page_slice_add);
int cl_page_init(void)
{
return 0;
}
void cl_page_fini(void)
{
}
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