// SPDX-License-Identifier: GPL-2.0-or-later
|
/* Cache page management and data I/O routines
|
*
|
* Copyright (C) 2004-2008 Red Hat, Inc. All Rights Reserved.
|
* Written by David Howells (dhowells@redhat.com)
|
*/
|
|
#define FSCACHE_DEBUG_LEVEL PAGE
|
#include <linux/module.h>
|
#include <linux/fscache-cache.h>
|
#include <linux/buffer_head.h>
|
#include <linux/pagevec.h>
|
#include <linux/slab.h>
|
#include "internal.h"
|
|
/*
|
* check to see if a page is being written to the cache
|
*/
|
bool __fscache_check_page_write(struct fscache_cookie *cookie, struct page *page)
|
{
|
void *val;
|
|
rcu_read_lock();
|
val = radix_tree_lookup(&cookie->stores, page->index);
|
rcu_read_unlock();
|
trace_fscache_check_page(cookie, page, val, 0);
|
|
return val != NULL;
|
}
|
EXPORT_SYMBOL(__fscache_check_page_write);
|
|
/*
|
* wait for a page to finish being written to the cache
|
*/
|
void __fscache_wait_on_page_write(struct fscache_cookie *cookie, struct page *page)
|
{
|
wait_queue_head_t *wq = bit_waitqueue(&cookie->flags, 0);
|
|
trace_fscache_page(cookie, page, fscache_page_write_wait);
|
|
wait_event(*wq, !__fscache_check_page_write(cookie, page));
|
}
|
EXPORT_SYMBOL(__fscache_wait_on_page_write);
|
|
/*
|
* wait for a page to finish being written to the cache. Put a timeout here
|
* since we might be called recursively via parent fs.
|
*/
|
static
|
bool release_page_wait_timeout(struct fscache_cookie *cookie, struct page *page)
|
{
|
wait_queue_head_t *wq = bit_waitqueue(&cookie->flags, 0);
|
|
return wait_event_timeout(*wq, !__fscache_check_page_write(cookie, page),
|
HZ);
|
}
|
|
/*
|
* decide whether a page can be released, possibly by cancelling a store to it
|
* - we're allowed to sleep if __GFP_DIRECT_RECLAIM is flagged
|
*/
|
bool __fscache_maybe_release_page(struct fscache_cookie *cookie,
|
struct page *page,
|
gfp_t gfp)
|
{
|
struct page *xpage;
|
void *val;
|
|
_enter("%p,%p,%x", cookie, page, gfp);
|
|
trace_fscache_page(cookie, page, fscache_page_maybe_release);
|
|
try_again:
|
rcu_read_lock();
|
val = radix_tree_lookup(&cookie->stores, page->index);
|
if (!val) {
|
rcu_read_unlock();
|
fscache_stat(&fscache_n_store_vmscan_not_storing);
|
__fscache_uncache_page(cookie, page);
|
return true;
|
}
|
|
/* see if the page is actually undergoing storage - if so we can't get
|
* rid of it till the cache has finished with it */
|
if (radix_tree_tag_get(&cookie->stores, page->index,
|
FSCACHE_COOKIE_STORING_TAG)) {
|
rcu_read_unlock();
|
goto page_busy;
|
}
|
|
/* the page is pending storage, so we attempt to cancel the store and
|
* discard the store request so that the page can be reclaimed */
|
spin_lock(&cookie->stores_lock);
|
rcu_read_unlock();
|
|
if (radix_tree_tag_get(&cookie->stores, page->index,
|
FSCACHE_COOKIE_STORING_TAG)) {
|
/* the page started to undergo storage whilst we were looking,
|
* so now we can only wait or return */
|
spin_unlock(&cookie->stores_lock);
|
goto page_busy;
|
}
|
|
xpage = radix_tree_delete(&cookie->stores, page->index);
|
trace_fscache_page(cookie, page, fscache_page_radix_delete);
|
spin_unlock(&cookie->stores_lock);
|
|
if (xpage) {
|
fscache_stat(&fscache_n_store_vmscan_cancelled);
|
fscache_stat(&fscache_n_store_radix_deletes);
|
ASSERTCMP(xpage, ==, page);
|
} else {
|
fscache_stat(&fscache_n_store_vmscan_gone);
|
}
|
|
wake_up_bit(&cookie->flags, 0);
|
trace_fscache_wake_cookie(cookie);
|
if (xpage)
|
put_page(xpage);
|
__fscache_uncache_page(cookie, page);
|
return true;
|
|
page_busy:
|
/* We will wait here if we're allowed to, but that could deadlock the
|
* allocator as the work threads writing to the cache may all end up
|
* sleeping on memory allocation, so we may need to impose a timeout
|
* too. */
|
if (!(gfp & __GFP_DIRECT_RECLAIM) || !(gfp & __GFP_FS)) {
|
fscache_stat(&fscache_n_store_vmscan_busy);
|
return false;
|
}
|
|
fscache_stat(&fscache_n_store_vmscan_wait);
|
if (!release_page_wait_timeout(cookie, page))
|
_debug("fscache writeout timeout page: %p{%lx}",
|
page, page->index);
|
|
gfp &= ~__GFP_DIRECT_RECLAIM;
|
goto try_again;
|
}
|
EXPORT_SYMBOL(__fscache_maybe_release_page);
|
|
/*
|
* note that a page has finished being written to the cache
|
*/
|
static void fscache_end_page_write(struct fscache_object *object,
|
struct page *page)
|
{
|
struct fscache_cookie *cookie;
|
struct page *xpage = NULL, *val;
|
|
spin_lock(&object->lock);
|
cookie = object->cookie;
|
if (cookie) {
|
/* delete the page from the tree if it is now no longer
|
* pending */
|
spin_lock(&cookie->stores_lock);
|
radix_tree_tag_clear(&cookie->stores, page->index,
|
FSCACHE_COOKIE_STORING_TAG);
|
trace_fscache_page(cookie, page, fscache_page_radix_clear_store);
|
if (!radix_tree_tag_get(&cookie->stores, page->index,
|
FSCACHE_COOKIE_PENDING_TAG)) {
|
fscache_stat(&fscache_n_store_radix_deletes);
|
xpage = radix_tree_delete(&cookie->stores, page->index);
|
trace_fscache_page(cookie, page, fscache_page_radix_delete);
|
trace_fscache_page(cookie, page, fscache_page_write_end);
|
|
val = radix_tree_lookup(&cookie->stores, page->index);
|
trace_fscache_check_page(cookie, page, val, 1);
|
} else {
|
trace_fscache_page(cookie, page, fscache_page_write_end_pend);
|
}
|
spin_unlock(&cookie->stores_lock);
|
wake_up_bit(&cookie->flags, 0);
|
trace_fscache_wake_cookie(cookie);
|
} else {
|
trace_fscache_page(cookie, page, fscache_page_write_end_noc);
|
}
|
spin_unlock(&object->lock);
|
if (xpage)
|
put_page(xpage);
|
}
|
|
/*
|
* actually apply the changed attributes to a cache object
|
*/
|
static void fscache_attr_changed_op(struct fscache_operation *op)
|
{
|
struct fscache_object *object = op->object;
|
int ret;
|
|
_enter("{OBJ%x OP%x}", object->debug_id, op->debug_id);
|
|
fscache_stat(&fscache_n_attr_changed_calls);
|
|
if (fscache_object_is_active(object)) {
|
fscache_stat(&fscache_n_cop_attr_changed);
|
ret = object->cache->ops->attr_changed(object);
|
fscache_stat_d(&fscache_n_cop_attr_changed);
|
if (ret < 0)
|
fscache_abort_object(object);
|
fscache_op_complete(op, ret < 0);
|
} else {
|
fscache_op_complete(op, true);
|
}
|
|
_leave("");
|
}
|
|
/*
|
* notification that the attributes on an object have changed
|
*/
|
int __fscache_attr_changed(struct fscache_cookie *cookie)
|
{
|
struct fscache_operation *op;
|
struct fscache_object *object;
|
bool wake_cookie = false;
|
|
_enter("%p", cookie);
|
|
ASSERTCMP(cookie->def->type, !=, FSCACHE_COOKIE_TYPE_INDEX);
|
|
fscache_stat(&fscache_n_attr_changed);
|
|
op = kzalloc(sizeof(*op), GFP_KERNEL);
|
if (!op) {
|
fscache_stat(&fscache_n_attr_changed_nomem);
|
_leave(" = -ENOMEM");
|
return -ENOMEM;
|
}
|
|
fscache_operation_init(cookie, op, fscache_attr_changed_op, NULL, NULL);
|
trace_fscache_page_op(cookie, NULL, op, fscache_page_op_attr_changed);
|
op->flags = FSCACHE_OP_ASYNC |
|
(1 << FSCACHE_OP_EXCLUSIVE) |
|
(1 << FSCACHE_OP_UNUSE_COOKIE);
|
|
spin_lock(&cookie->lock);
|
|
if (!fscache_cookie_enabled(cookie) ||
|
hlist_empty(&cookie->backing_objects))
|
goto nobufs;
|
object = hlist_entry(cookie->backing_objects.first,
|
struct fscache_object, cookie_link);
|
|
__fscache_use_cookie(cookie);
|
if (fscache_submit_exclusive_op(object, op) < 0)
|
goto nobufs_dec;
|
spin_unlock(&cookie->lock);
|
fscache_stat(&fscache_n_attr_changed_ok);
|
fscache_put_operation(op);
|
_leave(" = 0");
|
return 0;
|
|
nobufs_dec:
|
wake_cookie = __fscache_unuse_cookie(cookie);
|
nobufs:
|
spin_unlock(&cookie->lock);
|
fscache_put_operation(op);
|
if (wake_cookie)
|
__fscache_wake_unused_cookie(cookie);
|
fscache_stat(&fscache_n_attr_changed_nobufs);
|
_leave(" = %d", -ENOBUFS);
|
return -ENOBUFS;
|
}
|
EXPORT_SYMBOL(__fscache_attr_changed);
|
|
/*
|
* Handle cancellation of a pending retrieval op
|
*/
|
static void fscache_do_cancel_retrieval(struct fscache_operation *_op)
|
{
|
struct fscache_retrieval *op =
|
container_of(_op, struct fscache_retrieval, op);
|
|
atomic_set(&op->n_pages, 0);
|
}
|
|
/*
|
* release a retrieval op reference
|
*/
|
static void fscache_release_retrieval_op(struct fscache_operation *_op)
|
{
|
struct fscache_retrieval *op =
|
container_of(_op, struct fscache_retrieval, op);
|
|
_enter("{OP%x}", op->op.debug_id);
|
|
ASSERTIFCMP(op->op.state != FSCACHE_OP_ST_INITIALISED,
|
atomic_read(&op->n_pages), ==, 0);
|
|
fscache_hist(fscache_retrieval_histogram, op->start_time);
|
if (op->context)
|
fscache_put_context(op->cookie, op->context);
|
|
_leave("");
|
}
|
|
/*
|
* allocate a retrieval op
|
*/
|
static struct fscache_retrieval *fscache_alloc_retrieval(
|
struct fscache_cookie *cookie,
|
struct address_space *mapping,
|
fscache_rw_complete_t end_io_func,
|
void *context)
|
{
|
struct fscache_retrieval *op;
|
|
/* allocate a retrieval operation and attempt to submit it */
|
op = kzalloc(sizeof(*op), GFP_NOIO);
|
if (!op) {
|
fscache_stat(&fscache_n_retrievals_nomem);
|
return NULL;
|
}
|
|
fscache_operation_init(cookie, &op->op, NULL,
|
fscache_do_cancel_retrieval,
|
fscache_release_retrieval_op);
|
op->op.flags = FSCACHE_OP_MYTHREAD |
|
(1UL << FSCACHE_OP_WAITING) |
|
(1UL << FSCACHE_OP_UNUSE_COOKIE);
|
op->cookie = cookie;
|
op->mapping = mapping;
|
op->end_io_func = end_io_func;
|
op->context = context;
|
op->start_time = jiffies;
|
INIT_LIST_HEAD(&op->to_do);
|
|
/* Pin the netfs read context in case we need to do the actual netfs
|
* read because we've encountered a cache read failure.
|
*/
|
if (context)
|
fscache_get_context(op->cookie, context);
|
return op;
|
}
|
|
/*
|
* wait for a deferred lookup to complete
|
*/
|
int fscache_wait_for_deferred_lookup(struct fscache_cookie *cookie)
|
{
|
unsigned long jif;
|
|
_enter("");
|
|
if (!test_bit(FSCACHE_COOKIE_LOOKING_UP, &cookie->flags)) {
|
_leave(" = 0 [imm]");
|
return 0;
|
}
|
|
fscache_stat(&fscache_n_retrievals_wait);
|
|
jif = jiffies;
|
if (wait_on_bit(&cookie->flags, FSCACHE_COOKIE_LOOKING_UP,
|
TASK_INTERRUPTIBLE) != 0) {
|
fscache_stat(&fscache_n_retrievals_intr);
|
_leave(" = -ERESTARTSYS");
|
return -ERESTARTSYS;
|
}
|
|
ASSERT(!test_bit(FSCACHE_COOKIE_LOOKING_UP, &cookie->flags));
|
|
smp_rmb();
|
fscache_hist(fscache_retrieval_delay_histogram, jif);
|
_leave(" = 0 [dly]");
|
return 0;
|
}
|
|
/*
|
* wait for an object to become active (or dead)
|
*/
|
int fscache_wait_for_operation_activation(struct fscache_object *object,
|
struct fscache_operation *op,
|
atomic_t *stat_op_waits,
|
atomic_t *stat_object_dead)
|
{
|
int ret;
|
|
if (!test_bit(FSCACHE_OP_WAITING, &op->flags))
|
goto check_if_dead;
|
|
_debug(">>> WT");
|
if (stat_op_waits)
|
fscache_stat(stat_op_waits);
|
if (wait_on_bit(&op->flags, FSCACHE_OP_WAITING,
|
TASK_INTERRUPTIBLE) != 0) {
|
trace_fscache_op(object->cookie, op, fscache_op_signal);
|
ret = fscache_cancel_op(op, false);
|
if (ret == 0)
|
return -ERESTARTSYS;
|
|
/* it's been removed from the pending queue by another party,
|
* so we should get to run shortly */
|
wait_on_bit(&op->flags, FSCACHE_OP_WAITING,
|
TASK_UNINTERRUPTIBLE);
|
}
|
_debug("<<< GO");
|
|
check_if_dead:
|
if (op->state == FSCACHE_OP_ST_CANCELLED) {
|
if (stat_object_dead)
|
fscache_stat(stat_object_dead);
|
_leave(" = -ENOBUFS [cancelled]");
|
return -ENOBUFS;
|
}
|
if (unlikely(fscache_object_is_dying(object) ||
|
fscache_cache_is_broken(object))) {
|
enum fscache_operation_state state = op->state;
|
trace_fscache_op(object->cookie, op, fscache_op_signal);
|
fscache_cancel_op(op, true);
|
if (stat_object_dead)
|
fscache_stat(stat_object_dead);
|
_leave(" = -ENOBUFS [obj dead %d]", state);
|
return -ENOBUFS;
|
}
|
return 0;
|
}
|
|
/*
|
* read a page from the cache or allocate a block in which to store it
|
* - we return:
|
* -ENOMEM - out of memory, nothing done
|
* -ERESTARTSYS - interrupted
|
* -ENOBUFS - no backing object available in which to cache the block
|
* -ENODATA - no data available in the backing object for this block
|
* 0 - dispatched a read - it'll call end_io_func() when finished
|
*/
|
int __fscache_read_or_alloc_page(struct fscache_cookie *cookie,
|
struct page *page,
|
fscache_rw_complete_t end_io_func,
|
void *context,
|
gfp_t gfp)
|
{
|
struct fscache_retrieval *op;
|
struct fscache_object *object;
|
bool wake_cookie = false;
|
int ret;
|
|
_enter("%p,%p,,,", cookie, page);
|
|
fscache_stat(&fscache_n_retrievals);
|
|
if (hlist_empty(&cookie->backing_objects))
|
goto nobufs;
|
|
if (test_bit(FSCACHE_COOKIE_INVALIDATING, &cookie->flags)) {
|
_leave(" = -ENOBUFS [invalidating]");
|
return -ENOBUFS;
|
}
|
|
ASSERTCMP(cookie->def->type, !=, FSCACHE_COOKIE_TYPE_INDEX);
|
ASSERTCMP(page, !=, NULL);
|
|
if (fscache_wait_for_deferred_lookup(cookie) < 0)
|
return -ERESTARTSYS;
|
|
op = fscache_alloc_retrieval(cookie, page->mapping,
|
end_io_func, context);
|
if (!op) {
|
_leave(" = -ENOMEM");
|
return -ENOMEM;
|
}
|
atomic_set(&op->n_pages, 1);
|
trace_fscache_page_op(cookie, page, &op->op, fscache_page_op_retr_one);
|
|
spin_lock(&cookie->lock);
|
|
if (!fscache_cookie_enabled(cookie) ||
|
hlist_empty(&cookie->backing_objects))
|
goto nobufs_unlock;
|
object = hlist_entry(cookie->backing_objects.first,
|
struct fscache_object, cookie_link);
|
|
ASSERT(test_bit(FSCACHE_OBJECT_IS_LOOKED_UP, &object->flags));
|
|
__fscache_use_cookie(cookie);
|
atomic_inc(&object->n_reads);
|
__set_bit(FSCACHE_OP_DEC_READ_CNT, &op->op.flags);
|
|
if (fscache_submit_op(object, &op->op) < 0)
|
goto nobufs_unlock_dec;
|
spin_unlock(&cookie->lock);
|
|
fscache_stat(&fscache_n_retrieval_ops);
|
|
/* we wait for the operation to become active, and then process it
|
* *here*, in this thread, and not in the thread pool */
|
ret = fscache_wait_for_operation_activation(
|
object, &op->op,
|
__fscache_stat(&fscache_n_retrieval_op_waits),
|
__fscache_stat(&fscache_n_retrievals_object_dead));
|
if (ret < 0)
|
goto error;
|
|
/* ask the cache to honour the operation */
|
if (test_bit(FSCACHE_COOKIE_NO_DATA_YET, &object->cookie->flags)) {
|
fscache_stat(&fscache_n_cop_allocate_page);
|
ret = object->cache->ops->allocate_page(op, page, gfp);
|
fscache_stat_d(&fscache_n_cop_allocate_page);
|
if (ret == 0)
|
ret = -ENODATA;
|
} else {
|
fscache_stat(&fscache_n_cop_read_or_alloc_page);
|
ret = object->cache->ops->read_or_alloc_page(op, page, gfp);
|
fscache_stat_d(&fscache_n_cop_read_or_alloc_page);
|
}
|
|
error:
|
if (ret == -ENOMEM)
|
fscache_stat(&fscache_n_retrievals_nomem);
|
else if (ret == -ERESTARTSYS)
|
fscache_stat(&fscache_n_retrievals_intr);
|
else if (ret == -ENODATA)
|
fscache_stat(&fscache_n_retrievals_nodata);
|
else if (ret < 0)
|
fscache_stat(&fscache_n_retrievals_nobufs);
|
else
|
fscache_stat(&fscache_n_retrievals_ok);
|
|
fscache_put_retrieval(op);
|
_leave(" = %d", ret);
|
return ret;
|
|
nobufs_unlock_dec:
|
atomic_dec(&object->n_reads);
|
wake_cookie = __fscache_unuse_cookie(cookie);
|
nobufs_unlock:
|
spin_unlock(&cookie->lock);
|
if (wake_cookie)
|
__fscache_wake_unused_cookie(cookie);
|
fscache_put_retrieval(op);
|
nobufs:
|
fscache_stat(&fscache_n_retrievals_nobufs);
|
_leave(" = -ENOBUFS");
|
return -ENOBUFS;
|
}
|
EXPORT_SYMBOL(__fscache_read_or_alloc_page);
|
|
/*
|
* read a list of page from the cache or allocate a block in which to store
|
* them
|
* - we return:
|
* -ENOMEM - out of memory, some pages may be being read
|
* -ERESTARTSYS - interrupted, some pages may be being read
|
* -ENOBUFS - no backing object or space available in which to cache any
|
* pages not being read
|
* -ENODATA - no data available in the backing object for some or all of
|
* the pages
|
* 0 - dispatched a read on all pages
|
*
|
* end_io_func() will be called for each page read from the cache as it is
|
* finishes being read
|
*
|
* any pages for which a read is dispatched will be removed from pages and
|
* nr_pages
|
*/
|
int __fscache_read_or_alloc_pages(struct fscache_cookie *cookie,
|
struct address_space *mapping,
|
struct list_head *pages,
|
unsigned *nr_pages,
|
fscache_rw_complete_t end_io_func,
|
void *context,
|
gfp_t gfp)
|
{
|
struct fscache_retrieval *op;
|
struct fscache_object *object;
|
bool wake_cookie = false;
|
int ret;
|
|
_enter("%p,,%d,,,", cookie, *nr_pages);
|
|
fscache_stat(&fscache_n_retrievals);
|
|
if (hlist_empty(&cookie->backing_objects))
|
goto nobufs;
|
|
if (test_bit(FSCACHE_COOKIE_INVALIDATING, &cookie->flags)) {
|
_leave(" = -ENOBUFS [invalidating]");
|
return -ENOBUFS;
|
}
|
|
ASSERTCMP(cookie->def->type, !=, FSCACHE_COOKIE_TYPE_INDEX);
|
ASSERTCMP(*nr_pages, >, 0);
|
ASSERT(!list_empty(pages));
|
|
if (fscache_wait_for_deferred_lookup(cookie) < 0)
|
return -ERESTARTSYS;
|
|
op = fscache_alloc_retrieval(cookie, mapping, end_io_func, context);
|
if (!op)
|
return -ENOMEM;
|
atomic_set(&op->n_pages, *nr_pages);
|
trace_fscache_page_op(cookie, NULL, &op->op, fscache_page_op_retr_multi);
|
|
spin_lock(&cookie->lock);
|
|
if (!fscache_cookie_enabled(cookie) ||
|
hlist_empty(&cookie->backing_objects))
|
goto nobufs_unlock;
|
object = hlist_entry(cookie->backing_objects.first,
|
struct fscache_object, cookie_link);
|
|
__fscache_use_cookie(cookie);
|
atomic_inc(&object->n_reads);
|
__set_bit(FSCACHE_OP_DEC_READ_CNT, &op->op.flags);
|
|
if (fscache_submit_op(object, &op->op) < 0)
|
goto nobufs_unlock_dec;
|
spin_unlock(&cookie->lock);
|
|
fscache_stat(&fscache_n_retrieval_ops);
|
|
/* we wait for the operation to become active, and then process it
|
* *here*, in this thread, and not in the thread pool */
|
ret = fscache_wait_for_operation_activation(
|
object, &op->op,
|
__fscache_stat(&fscache_n_retrieval_op_waits),
|
__fscache_stat(&fscache_n_retrievals_object_dead));
|
if (ret < 0)
|
goto error;
|
|
/* ask the cache to honour the operation */
|
if (test_bit(FSCACHE_COOKIE_NO_DATA_YET, &object->cookie->flags)) {
|
fscache_stat(&fscache_n_cop_allocate_pages);
|
ret = object->cache->ops->allocate_pages(
|
op, pages, nr_pages, gfp);
|
fscache_stat_d(&fscache_n_cop_allocate_pages);
|
} else {
|
fscache_stat(&fscache_n_cop_read_or_alloc_pages);
|
ret = object->cache->ops->read_or_alloc_pages(
|
op, pages, nr_pages, gfp);
|
fscache_stat_d(&fscache_n_cop_read_or_alloc_pages);
|
}
|
|
error:
|
if (ret == -ENOMEM)
|
fscache_stat(&fscache_n_retrievals_nomem);
|
else if (ret == -ERESTARTSYS)
|
fscache_stat(&fscache_n_retrievals_intr);
|
else if (ret == -ENODATA)
|
fscache_stat(&fscache_n_retrievals_nodata);
|
else if (ret < 0)
|
fscache_stat(&fscache_n_retrievals_nobufs);
|
else
|
fscache_stat(&fscache_n_retrievals_ok);
|
|
fscache_put_retrieval(op);
|
_leave(" = %d", ret);
|
return ret;
|
|
nobufs_unlock_dec:
|
atomic_dec(&object->n_reads);
|
wake_cookie = __fscache_unuse_cookie(cookie);
|
nobufs_unlock:
|
spin_unlock(&cookie->lock);
|
fscache_put_retrieval(op);
|
if (wake_cookie)
|
__fscache_wake_unused_cookie(cookie);
|
nobufs:
|
fscache_stat(&fscache_n_retrievals_nobufs);
|
_leave(" = -ENOBUFS");
|
return -ENOBUFS;
|
}
|
EXPORT_SYMBOL(__fscache_read_or_alloc_pages);
|
|
/*
|
* allocate a block in the cache on which to store a page
|
* - we return:
|
* -ENOMEM - out of memory, nothing done
|
* -ERESTARTSYS - interrupted
|
* -ENOBUFS - no backing object available in which to cache the block
|
* 0 - block allocated
|
*/
|
int __fscache_alloc_page(struct fscache_cookie *cookie,
|
struct page *page,
|
gfp_t gfp)
|
{
|
struct fscache_retrieval *op;
|
struct fscache_object *object;
|
bool wake_cookie = false;
|
int ret;
|
|
_enter("%p,%p,,,", cookie, page);
|
|
fscache_stat(&fscache_n_allocs);
|
|
if (hlist_empty(&cookie->backing_objects))
|
goto nobufs;
|
|
ASSERTCMP(cookie->def->type, !=, FSCACHE_COOKIE_TYPE_INDEX);
|
ASSERTCMP(page, !=, NULL);
|
|
if (test_bit(FSCACHE_COOKIE_INVALIDATING, &cookie->flags)) {
|
_leave(" = -ENOBUFS [invalidating]");
|
return -ENOBUFS;
|
}
|
|
if (fscache_wait_for_deferred_lookup(cookie) < 0)
|
return -ERESTARTSYS;
|
|
op = fscache_alloc_retrieval(cookie, page->mapping, NULL, NULL);
|
if (!op)
|
return -ENOMEM;
|
atomic_set(&op->n_pages, 1);
|
trace_fscache_page_op(cookie, page, &op->op, fscache_page_op_alloc_one);
|
|
spin_lock(&cookie->lock);
|
|
if (!fscache_cookie_enabled(cookie) ||
|
hlist_empty(&cookie->backing_objects))
|
goto nobufs_unlock;
|
object = hlist_entry(cookie->backing_objects.first,
|
struct fscache_object, cookie_link);
|
|
__fscache_use_cookie(cookie);
|
if (fscache_submit_op(object, &op->op) < 0)
|
goto nobufs_unlock_dec;
|
spin_unlock(&cookie->lock);
|
|
fscache_stat(&fscache_n_alloc_ops);
|
|
ret = fscache_wait_for_operation_activation(
|
object, &op->op,
|
__fscache_stat(&fscache_n_alloc_op_waits),
|
__fscache_stat(&fscache_n_allocs_object_dead));
|
if (ret < 0)
|
goto error;
|
|
/* ask the cache to honour the operation */
|
fscache_stat(&fscache_n_cop_allocate_page);
|
ret = object->cache->ops->allocate_page(op, page, gfp);
|
fscache_stat_d(&fscache_n_cop_allocate_page);
|
|
error:
|
if (ret == -ERESTARTSYS)
|
fscache_stat(&fscache_n_allocs_intr);
|
else if (ret < 0)
|
fscache_stat(&fscache_n_allocs_nobufs);
|
else
|
fscache_stat(&fscache_n_allocs_ok);
|
|
fscache_put_retrieval(op);
|
_leave(" = %d", ret);
|
return ret;
|
|
nobufs_unlock_dec:
|
wake_cookie = __fscache_unuse_cookie(cookie);
|
nobufs_unlock:
|
spin_unlock(&cookie->lock);
|
fscache_put_retrieval(op);
|
if (wake_cookie)
|
__fscache_wake_unused_cookie(cookie);
|
nobufs:
|
fscache_stat(&fscache_n_allocs_nobufs);
|
_leave(" = -ENOBUFS");
|
return -ENOBUFS;
|
}
|
EXPORT_SYMBOL(__fscache_alloc_page);
|
|
/*
|
* Unmark pages allocate in the readahead code path (via:
|
* fscache_readpages_or_alloc) after delegating to the base filesystem
|
*/
|
void __fscache_readpages_cancel(struct fscache_cookie *cookie,
|
struct list_head *pages)
|
{
|
struct page *page;
|
|
list_for_each_entry(page, pages, lru) {
|
if (PageFsCache(page))
|
__fscache_uncache_page(cookie, page);
|
}
|
}
|
EXPORT_SYMBOL(__fscache_readpages_cancel);
|
|
/*
|
* release a write op reference
|
*/
|
static void fscache_release_write_op(struct fscache_operation *_op)
|
{
|
_enter("{OP%x}", _op->debug_id);
|
}
|
|
/*
|
* perform the background storage of a page into the cache
|
*/
|
static void fscache_write_op(struct fscache_operation *_op)
|
{
|
struct fscache_storage *op =
|
container_of(_op, struct fscache_storage, op);
|
struct fscache_object *object = op->op.object;
|
struct fscache_cookie *cookie;
|
struct page *page;
|
unsigned n;
|
void *results[1];
|
int ret;
|
|
_enter("{OP%x,%d}", op->op.debug_id, atomic_read(&op->op.usage));
|
|
again:
|
spin_lock(&object->lock);
|
cookie = object->cookie;
|
|
if (!fscache_object_is_active(object)) {
|
/* If we get here, then the on-disk cache object likely no
|
* longer exists, so we should just cancel this write
|
* operation.
|
*/
|
spin_unlock(&object->lock);
|
fscache_op_complete(&op->op, true);
|
_leave(" [inactive]");
|
return;
|
}
|
|
if (!cookie) {
|
/* If we get here, then the cookie belonging to the object was
|
* detached, probably by the cookie being withdrawn due to
|
* memory pressure, which means that the pages we might write
|
* to the cache from no longer exist - therefore, we can just
|
* cancel this write operation.
|
*/
|
spin_unlock(&object->lock);
|
fscache_op_complete(&op->op, true);
|
_leave(" [cancel] op{f=%lx s=%u} obj{s=%s f=%lx}",
|
_op->flags, _op->state, object->state->short_name,
|
object->flags);
|
return;
|
}
|
|
spin_lock(&cookie->stores_lock);
|
|
fscache_stat(&fscache_n_store_calls);
|
|
/* find a page to store */
|
results[0] = NULL;
|
page = NULL;
|
n = radix_tree_gang_lookup_tag(&cookie->stores, results, 0, 1,
|
FSCACHE_COOKIE_PENDING_TAG);
|
trace_fscache_gang_lookup(cookie, &op->op, results, n, op->store_limit);
|
if (n != 1)
|
goto superseded;
|
page = results[0];
|
_debug("gang %d [%lx]", n, page->index);
|
|
radix_tree_tag_set(&cookie->stores, page->index,
|
FSCACHE_COOKIE_STORING_TAG);
|
radix_tree_tag_clear(&cookie->stores, page->index,
|
FSCACHE_COOKIE_PENDING_TAG);
|
trace_fscache_page(cookie, page, fscache_page_radix_pend2store);
|
|
spin_unlock(&cookie->stores_lock);
|
spin_unlock(&object->lock);
|
|
if (page->index >= op->store_limit)
|
goto discard_page;
|
|
fscache_stat(&fscache_n_store_pages);
|
fscache_stat(&fscache_n_cop_write_page);
|
ret = object->cache->ops->write_page(op, page);
|
fscache_stat_d(&fscache_n_cop_write_page);
|
trace_fscache_wrote_page(cookie, page, &op->op, ret);
|
fscache_end_page_write(object, page);
|
if (ret < 0) {
|
fscache_abort_object(object);
|
fscache_op_complete(&op->op, true);
|
} else {
|
fscache_enqueue_operation(&op->op);
|
}
|
|
_leave("");
|
return;
|
|
discard_page:
|
fscache_stat(&fscache_n_store_pages_over_limit);
|
trace_fscache_wrote_page(cookie, page, &op->op, -ENOBUFS);
|
fscache_end_page_write(object, page);
|
goto again;
|
|
superseded:
|
/* this writer is going away and there aren't any more things to
|
* write */
|
_debug("cease");
|
spin_unlock(&cookie->stores_lock);
|
clear_bit(FSCACHE_OBJECT_PENDING_WRITE, &object->flags);
|
spin_unlock(&object->lock);
|
fscache_op_complete(&op->op, false);
|
_leave("");
|
}
|
|
/*
|
* Clear the pages pending writing for invalidation
|
*/
|
void fscache_invalidate_writes(struct fscache_cookie *cookie)
|
{
|
struct page *page;
|
void *results[16];
|
int n, i;
|
|
_enter("");
|
|
for (;;) {
|
spin_lock(&cookie->stores_lock);
|
n = radix_tree_gang_lookup_tag(&cookie->stores, results, 0,
|
ARRAY_SIZE(results),
|
FSCACHE_COOKIE_PENDING_TAG);
|
if (n == 0) {
|
spin_unlock(&cookie->stores_lock);
|
break;
|
}
|
|
for (i = n - 1; i >= 0; i--) {
|
page = results[i];
|
radix_tree_delete(&cookie->stores, page->index);
|
trace_fscache_page(cookie, page, fscache_page_radix_delete);
|
trace_fscache_page(cookie, page, fscache_page_inval);
|
}
|
|
spin_unlock(&cookie->stores_lock);
|
|
for (i = n - 1; i >= 0; i--)
|
put_page(results[i]);
|
}
|
|
wake_up_bit(&cookie->flags, 0);
|
trace_fscache_wake_cookie(cookie);
|
|
_leave("");
|
}
|
|
/*
|
* request a page be stored in the cache
|
* - returns:
|
* -ENOMEM - out of memory, nothing done
|
* -ENOBUFS - no backing object available in which to cache the page
|
* 0 - dispatched a write - it'll call end_io_func() when finished
|
*
|
* if the cookie still has a backing object at this point, that object can be
|
* in one of a few states with respect to storage processing:
|
*
|
* (1) negative lookup, object not yet created (FSCACHE_COOKIE_CREATING is
|
* set)
|
*
|
* (a) no writes yet
|
*
|
* (b) writes deferred till post-creation (mark page for writing and
|
* return immediately)
|
*
|
* (2) negative lookup, object created, initial fill being made from netfs
|
*
|
* (a) fill point not yet reached this page (mark page for writing and
|
* return)
|
*
|
* (b) fill point passed this page (queue op to store this page)
|
*
|
* (3) object extant (queue op to store this page)
|
*
|
* any other state is invalid
|
*/
|
int __fscache_write_page(struct fscache_cookie *cookie,
|
struct page *page,
|
loff_t object_size,
|
gfp_t gfp)
|
{
|
struct fscache_storage *op;
|
struct fscache_object *object;
|
bool wake_cookie = false;
|
int ret;
|
|
_enter("%p,%x,", cookie, (u32) page->flags);
|
|
ASSERTCMP(cookie->def->type, !=, FSCACHE_COOKIE_TYPE_INDEX);
|
ASSERT(PageFsCache(page));
|
|
fscache_stat(&fscache_n_stores);
|
|
if (test_bit(FSCACHE_COOKIE_INVALIDATING, &cookie->flags)) {
|
_leave(" = -ENOBUFS [invalidating]");
|
return -ENOBUFS;
|
}
|
|
op = kzalloc(sizeof(*op), GFP_NOIO | __GFP_NOMEMALLOC | __GFP_NORETRY);
|
if (!op)
|
goto nomem;
|
|
fscache_operation_init(cookie, &op->op, fscache_write_op, NULL,
|
fscache_release_write_op);
|
op->op.flags = FSCACHE_OP_ASYNC |
|
(1 << FSCACHE_OP_WAITING) |
|
(1 << FSCACHE_OP_UNUSE_COOKIE);
|
|
ret = radix_tree_maybe_preload(gfp & ~__GFP_HIGHMEM);
|
if (ret < 0)
|
goto nomem_free;
|
|
trace_fscache_page_op(cookie, page, &op->op, fscache_page_op_write_one);
|
|
ret = -ENOBUFS;
|
spin_lock(&cookie->lock);
|
|
if (!fscache_cookie_enabled(cookie) ||
|
hlist_empty(&cookie->backing_objects))
|
goto nobufs;
|
object = hlist_entry(cookie->backing_objects.first,
|
struct fscache_object, cookie_link);
|
if (test_bit(FSCACHE_IOERROR, &object->cache->flags))
|
goto nobufs;
|
|
trace_fscache_page(cookie, page, fscache_page_write);
|
|
/* add the page to the pending-storage radix tree on the backing
|
* object */
|
spin_lock(&object->lock);
|
|
if (object->store_limit_l != object_size)
|
fscache_set_store_limit(object, object_size);
|
|
spin_lock(&cookie->stores_lock);
|
|
_debug("store limit %llx", (unsigned long long) object->store_limit);
|
|
ret = radix_tree_insert(&cookie->stores, page->index, page);
|
if (ret < 0) {
|
if (ret == -EEXIST)
|
goto already_queued;
|
_debug("insert failed %d", ret);
|
goto nobufs_unlock_obj;
|
}
|
|
trace_fscache_page(cookie, page, fscache_page_radix_insert);
|
radix_tree_tag_set(&cookie->stores, page->index,
|
FSCACHE_COOKIE_PENDING_TAG);
|
trace_fscache_page(cookie, page, fscache_page_radix_set_pend);
|
get_page(page);
|
|
/* we only want one writer at a time, but we do need to queue new
|
* writers after exclusive ops */
|
if (test_and_set_bit(FSCACHE_OBJECT_PENDING_WRITE, &object->flags))
|
goto already_pending;
|
|
spin_unlock(&cookie->stores_lock);
|
spin_unlock(&object->lock);
|
|
op->op.debug_id = atomic_inc_return(&fscache_op_debug_id);
|
op->store_limit = object->store_limit;
|
|
__fscache_use_cookie(cookie);
|
if (fscache_submit_op(object, &op->op) < 0)
|
goto submit_failed;
|
|
spin_unlock(&cookie->lock);
|
radix_tree_preload_end();
|
fscache_stat(&fscache_n_store_ops);
|
fscache_stat(&fscache_n_stores_ok);
|
|
/* the work queue now carries its own ref on the object */
|
fscache_put_operation(&op->op);
|
_leave(" = 0");
|
return 0;
|
|
already_queued:
|
fscache_stat(&fscache_n_stores_again);
|
already_pending:
|
spin_unlock(&cookie->stores_lock);
|
spin_unlock(&object->lock);
|
spin_unlock(&cookie->lock);
|
radix_tree_preload_end();
|
fscache_put_operation(&op->op);
|
fscache_stat(&fscache_n_stores_ok);
|
_leave(" = 0");
|
return 0;
|
|
submit_failed:
|
spin_lock(&cookie->stores_lock);
|
radix_tree_delete(&cookie->stores, page->index);
|
trace_fscache_page(cookie, page, fscache_page_radix_delete);
|
spin_unlock(&cookie->stores_lock);
|
wake_cookie = __fscache_unuse_cookie(cookie);
|
put_page(page);
|
ret = -ENOBUFS;
|
goto nobufs;
|
|
nobufs_unlock_obj:
|
spin_unlock(&cookie->stores_lock);
|
spin_unlock(&object->lock);
|
nobufs:
|
spin_unlock(&cookie->lock);
|
radix_tree_preload_end();
|
fscache_put_operation(&op->op);
|
if (wake_cookie)
|
__fscache_wake_unused_cookie(cookie);
|
fscache_stat(&fscache_n_stores_nobufs);
|
_leave(" = -ENOBUFS");
|
return -ENOBUFS;
|
|
nomem_free:
|
fscache_put_operation(&op->op);
|
nomem:
|
fscache_stat(&fscache_n_stores_oom);
|
_leave(" = -ENOMEM");
|
return -ENOMEM;
|
}
|
EXPORT_SYMBOL(__fscache_write_page);
|
|
/*
|
* remove a page from the cache
|
*/
|
void __fscache_uncache_page(struct fscache_cookie *cookie, struct page *page)
|
{
|
struct fscache_object *object;
|
|
_enter(",%p", page);
|
|
ASSERTCMP(cookie->def->type, !=, FSCACHE_COOKIE_TYPE_INDEX);
|
ASSERTCMP(page, !=, NULL);
|
|
fscache_stat(&fscache_n_uncaches);
|
|
/* cache withdrawal may beat us to it */
|
if (!PageFsCache(page))
|
goto done;
|
|
trace_fscache_page(cookie, page, fscache_page_uncache);
|
|
/* get the object */
|
spin_lock(&cookie->lock);
|
|
if (hlist_empty(&cookie->backing_objects)) {
|
ClearPageFsCache(page);
|
goto done_unlock;
|
}
|
|
object = hlist_entry(cookie->backing_objects.first,
|
struct fscache_object, cookie_link);
|
|
/* there might now be stuff on disk we could read */
|
clear_bit(FSCACHE_COOKIE_NO_DATA_YET, &cookie->flags);
|
|
/* only invoke the cache backend if we managed to mark the page
|
* uncached here; this deals with synchronisation vs withdrawal */
|
if (TestClearPageFsCache(page) &&
|
object->cache->ops->uncache_page) {
|
/* the cache backend releases the cookie lock */
|
fscache_stat(&fscache_n_cop_uncache_page);
|
object->cache->ops->uncache_page(object, page);
|
fscache_stat_d(&fscache_n_cop_uncache_page);
|
goto done;
|
}
|
|
done_unlock:
|
spin_unlock(&cookie->lock);
|
done:
|
_leave("");
|
}
|
EXPORT_SYMBOL(__fscache_uncache_page);
|
|
/**
|
* fscache_mark_page_cached - Mark a page as being cached
|
* @op: The retrieval op pages are being marked for
|
* @page: The page to be marked
|
*
|
* Mark a netfs page as being cached. After this is called, the netfs
|
* must call fscache_uncache_page() to remove the mark.
|
*/
|
void fscache_mark_page_cached(struct fscache_retrieval *op, struct page *page)
|
{
|
struct fscache_cookie *cookie = op->op.object->cookie;
|
|
#ifdef CONFIG_FSCACHE_STATS
|
atomic_inc(&fscache_n_marks);
|
#endif
|
|
trace_fscache_page(cookie, page, fscache_page_cached);
|
|
_debug("- mark %p{%lx}", page, page->index);
|
if (TestSetPageFsCache(page)) {
|
static bool once_only;
|
if (!once_only) {
|
once_only = true;
|
pr_warn("Cookie type %s marked page %lx multiple times\n",
|
cookie->def->name, page->index);
|
}
|
}
|
|
if (cookie->def->mark_page_cached)
|
cookie->def->mark_page_cached(cookie->netfs_data,
|
op->mapping, page);
|
}
|
EXPORT_SYMBOL(fscache_mark_page_cached);
|
|
/**
|
* fscache_mark_pages_cached - Mark pages as being cached
|
* @op: The retrieval op pages are being marked for
|
* @pagevec: The pages to be marked
|
*
|
* Mark a bunch of netfs pages as being cached. After this is called,
|
* the netfs must call fscache_uncache_page() to remove the mark.
|
*/
|
void fscache_mark_pages_cached(struct fscache_retrieval *op,
|
struct pagevec *pagevec)
|
{
|
unsigned long loop;
|
|
for (loop = 0; loop < pagevec->nr; loop++)
|
fscache_mark_page_cached(op, pagevec->pages[loop]);
|
|
pagevec_reinit(pagevec);
|
}
|
EXPORT_SYMBOL(fscache_mark_pages_cached);
|
|
/*
|
* Uncache all the pages in an inode that are marked PG_fscache, assuming them
|
* to be associated with the given cookie.
|
*/
|
void __fscache_uncache_all_inode_pages(struct fscache_cookie *cookie,
|
struct inode *inode)
|
{
|
struct address_space *mapping = inode->i_mapping;
|
struct pagevec pvec;
|
pgoff_t next;
|
int i;
|
|
_enter("%p,%p", cookie, inode);
|
|
if (!mapping || mapping->nrpages == 0) {
|
_leave(" [no pages]");
|
return;
|
}
|
|
pagevec_init(&pvec);
|
next = 0;
|
do {
|
if (!pagevec_lookup(&pvec, mapping, &next))
|
break;
|
for (i = 0; i < pagevec_count(&pvec); i++) {
|
struct page *page = pvec.pages[i];
|
if (PageFsCache(page)) {
|
__fscache_wait_on_page_write(cookie, page);
|
__fscache_uncache_page(cookie, page);
|
}
|
}
|
pagevec_release(&pvec);
|
cond_resched();
|
} while (next);
|
|
_leave("");
|
}
|
EXPORT_SYMBOL(__fscache_uncache_all_inode_pages);
|
