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08a66859e6
fscache_write_op() makes unnecessary checks of the page variable to see if it is NULL. It can't be NULL at those points as the kernel would already have crashed a little higher up where we examined page->index. Furthermore, unless radix_tree_gang_lookup_tag() can return 1 but no page, a NULL pointer crash should not be encountered there as we can only get there if r_t_g_l_t() returned 1. Signed-off-by: Dan Carpenter <error27@gmail.com> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
990 lines
26 KiB
C
990 lines
26 KiB
C
/* Cache page management and data I/O routines
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*
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* Copyright (C) 2004-2008 Red Hat, Inc. All Rights Reserved.
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* Written by David Howells (dhowells@redhat.com)
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#define FSCACHE_DEBUG_LEVEL PAGE
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#include <linux/module.h>
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#include <linux/fscache-cache.h>
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#include <linux/buffer_head.h>
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#include <linux/pagevec.h>
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#include <linux/slab.h>
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#include "internal.h"
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/*
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* check to see if a page is being written to the cache
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*/
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bool __fscache_check_page_write(struct fscache_cookie *cookie, struct page *page)
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{
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void *val;
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rcu_read_lock();
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val = radix_tree_lookup(&cookie->stores, page->index);
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rcu_read_unlock();
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return val != NULL;
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}
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EXPORT_SYMBOL(__fscache_check_page_write);
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/*
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* wait for a page to finish being written to the cache
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*/
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void __fscache_wait_on_page_write(struct fscache_cookie *cookie, struct page *page)
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{
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wait_queue_head_t *wq = bit_waitqueue(&cookie->flags, 0);
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wait_event(*wq, !__fscache_check_page_write(cookie, page));
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}
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EXPORT_SYMBOL(__fscache_wait_on_page_write);
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/*
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* decide whether a page can be released, possibly by cancelling a store to it
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* - we're allowed to sleep if __GFP_WAIT is flagged
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*/
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bool __fscache_maybe_release_page(struct fscache_cookie *cookie,
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struct page *page,
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gfp_t gfp)
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{
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struct page *xpage;
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void *val;
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_enter("%p,%p,%x", cookie, page, gfp);
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rcu_read_lock();
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val = radix_tree_lookup(&cookie->stores, page->index);
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if (!val) {
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rcu_read_unlock();
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fscache_stat(&fscache_n_store_vmscan_not_storing);
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__fscache_uncache_page(cookie, page);
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return true;
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}
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/* see if the page is actually undergoing storage - if so we can't get
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* rid of it till the cache has finished with it */
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if (radix_tree_tag_get(&cookie->stores, page->index,
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FSCACHE_COOKIE_STORING_TAG)) {
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rcu_read_unlock();
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goto page_busy;
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}
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/* the page is pending storage, so we attempt to cancel the store and
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* discard the store request so that the page can be reclaimed */
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spin_lock(&cookie->stores_lock);
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rcu_read_unlock();
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if (radix_tree_tag_get(&cookie->stores, page->index,
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FSCACHE_COOKIE_STORING_TAG)) {
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/* the page started to undergo storage whilst we were looking,
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* so now we can only wait or return */
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spin_unlock(&cookie->stores_lock);
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goto page_busy;
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}
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xpage = radix_tree_delete(&cookie->stores, page->index);
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spin_unlock(&cookie->stores_lock);
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if (xpage) {
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fscache_stat(&fscache_n_store_vmscan_cancelled);
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fscache_stat(&fscache_n_store_radix_deletes);
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ASSERTCMP(xpage, ==, page);
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} else {
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fscache_stat(&fscache_n_store_vmscan_gone);
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}
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wake_up_bit(&cookie->flags, 0);
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if (xpage)
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page_cache_release(xpage);
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__fscache_uncache_page(cookie, page);
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return true;
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page_busy:
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/* we might want to wait here, but that could deadlock the allocator as
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* the slow-work threads writing to the cache may all end up sleeping
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* on memory allocation */
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fscache_stat(&fscache_n_store_vmscan_busy);
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return false;
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}
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EXPORT_SYMBOL(__fscache_maybe_release_page);
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/*
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* note that a page has finished being written to the cache
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*/
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static void fscache_end_page_write(struct fscache_object *object,
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struct page *page)
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{
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struct fscache_cookie *cookie;
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struct page *xpage = NULL;
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spin_lock(&object->lock);
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cookie = object->cookie;
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if (cookie) {
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/* delete the page from the tree if it is now no longer
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* pending */
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spin_lock(&cookie->stores_lock);
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radix_tree_tag_clear(&cookie->stores, page->index,
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FSCACHE_COOKIE_STORING_TAG);
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if (!radix_tree_tag_get(&cookie->stores, page->index,
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FSCACHE_COOKIE_PENDING_TAG)) {
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fscache_stat(&fscache_n_store_radix_deletes);
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xpage = radix_tree_delete(&cookie->stores, page->index);
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}
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spin_unlock(&cookie->stores_lock);
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wake_up_bit(&cookie->flags, 0);
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}
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spin_unlock(&object->lock);
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if (xpage)
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page_cache_release(xpage);
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}
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/*
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* actually apply the changed attributes to a cache object
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*/
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static void fscache_attr_changed_op(struct fscache_operation *op)
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{
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struct fscache_object *object = op->object;
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int ret;
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_enter("{OBJ%x OP%x}", object->debug_id, op->debug_id);
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fscache_stat(&fscache_n_attr_changed_calls);
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if (fscache_object_is_active(object)) {
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fscache_set_op_state(op, "CallFS");
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fscache_stat(&fscache_n_cop_attr_changed);
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ret = object->cache->ops->attr_changed(object);
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fscache_stat_d(&fscache_n_cop_attr_changed);
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fscache_set_op_state(op, "Done");
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if (ret < 0)
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fscache_abort_object(object);
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}
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_leave("");
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}
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/*
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* notification that the attributes on an object have changed
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*/
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int __fscache_attr_changed(struct fscache_cookie *cookie)
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{
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struct fscache_operation *op;
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struct fscache_object *object;
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_enter("%p", cookie);
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ASSERTCMP(cookie->def->type, !=, FSCACHE_COOKIE_TYPE_INDEX);
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fscache_stat(&fscache_n_attr_changed);
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op = kzalloc(sizeof(*op), GFP_KERNEL);
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if (!op) {
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fscache_stat(&fscache_n_attr_changed_nomem);
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_leave(" = -ENOMEM");
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return -ENOMEM;
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}
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fscache_operation_init(op, NULL);
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fscache_operation_init_slow(op, fscache_attr_changed_op);
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op->flags = FSCACHE_OP_SLOW | (1 << FSCACHE_OP_EXCLUSIVE);
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fscache_set_op_name(op, "Attr");
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spin_lock(&cookie->lock);
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if (hlist_empty(&cookie->backing_objects))
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goto nobufs;
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object = hlist_entry(cookie->backing_objects.first,
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struct fscache_object, cookie_link);
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if (fscache_submit_exclusive_op(object, op) < 0)
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goto nobufs;
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spin_unlock(&cookie->lock);
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fscache_stat(&fscache_n_attr_changed_ok);
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fscache_put_operation(op);
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_leave(" = 0");
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return 0;
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nobufs:
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spin_unlock(&cookie->lock);
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kfree(op);
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fscache_stat(&fscache_n_attr_changed_nobufs);
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_leave(" = %d", -ENOBUFS);
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return -ENOBUFS;
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}
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EXPORT_SYMBOL(__fscache_attr_changed);
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/*
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* handle secondary execution given to a retrieval op on behalf of the
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* cache
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*/
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static void fscache_retrieval_work(struct work_struct *work)
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{
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struct fscache_retrieval *op =
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container_of(work, struct fscache_retrieval, op.fast_work);
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unsigned long start;
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_enter("{OP%x}", op->op.debug_id);
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start = jiffies;
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op->op.processor(&op->op);
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fscache_hist(fscache_ops_histogram, start);
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fscache_put_operation(&op->op);
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}
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/*
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* release a retrieval op reference
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*/
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static void fscache_release_retrieval_op(struct fscache_operation *_op)
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{
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struct fscache_retrieval *op =
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container_of(_op, struct fscache_retrieval, op);
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_enter("{OP%x}", op->op.debug_id);
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fscache_hist(fscache_retrieval_histogram, op->start_time);
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if (op->context)
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fscache_put_context(op->op.object->cookie, op->context);
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_leave("");
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}
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/*
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* allocate a retrieval op
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*/
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static struct fscache_retrieval *fscache_alloc_retrieval(
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struct address_space *mapping,
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fscache_rw_complete_t end_io_func,
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void *context)
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{
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struct fscache_retrieval *op;
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/* allocate a retrieval operation and attempt to submit it */
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op = kzalloc(sizeof(*op), GFP_NOIO);
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if (!op) {
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fscache_stat(&fscache_n_retrievals_nomem);
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return NULL;
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}
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fscache_operation_init(&op->op, fscache_release_retrieval_op);
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op->op.flags = FSCACHE_OP_MYTHREAD | (1 << FSCACHE_OP_WAITING);
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op->mapping = mapping;
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op->end_io_func = end_io_func;
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op->context = context;
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op->start_time = jiffies;
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INIT_WORK(&op->op.fast_work, fscache_retrieval_work);
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INIT_LIST_HEAD(&op->to_do);
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fscache_set_op_name(&op->op, "Retr");
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return op;
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}
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/*
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* wait for a deferred lookup to complete
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*/
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static int fscache_wait_for_deferred_lookup(struct fscache_cookie *cookie)
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{
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unsigned long jif;
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_enter("");
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if (!test_bit(FSCACHE_COOKIE_LOOKING_UP, &cookie->flags)) {
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_leave(" = 0 [imm]");
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return 0;
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}
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fscache_stat(&fscache_n_retrievals_wait);
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jif = jiffies;
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if (wait_on_bit(&cookie->flags, FSCACHE_COOKIE_LOOKING_UP,
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fscache_wait_bit_interruptible,
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TASK_INTERRUPTIBLE) != 0) {
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fscache_stat(&fscache_n_retrievals_intr);
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_leave(" = -ERESTARTSYS");
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return -ERESTARTSYS;
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}
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ASSERT(!test_bit(FSCACHE_COOKIE_LOOKING_UP, &cookie->flags));
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smp_rmb();
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fscache_hist(fscache_retrieval_delay_histogram, jif);
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_leave(" = 0 [dly]");
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return 0;
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}
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/*
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* wait for an object to become active (or dead)
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*/
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static int fscache_wait_for_retrieval_activation(struct fscache_object *object,
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struct fscache_retrieval *op,
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atomic_t *stat_op_waits,
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atomic_t *stat_object_dead)
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{
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int ret;
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if (!test_bit(FSCACHE_OP_WAITING, &op->op.flags))
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goto check_if_dead;
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_debug(">>> WT");
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fscache_stat(stat_op_waits);
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if (wait_on_bit(&op->op.flags, FSCACHE_OP_WAITING,
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fscache_wait_bit_interruptible,
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TASK_INTERRUPTIBLE) < 0) {
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ret = fscache_cancel_op(&op->op);
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if (ret == 0)
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return -ERESTARTSYS;
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/* it's been removed from the pending queue by another party,
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* so we should get to run shortly */
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wait_on_bit(&op->op.flags, FSCACHE_OP_WAITING,
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fscache_wait_bit, TASK_UNINTERRUPTIBLE);
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}
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_debug("<<< GO");
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check_if_dead:
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if (unlikely(fscache_object_is_dead(object))) {
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fscache_stat(stat_object_dead);
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return -ENOBUFS;
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}
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return 0;
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}
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/*
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* read a page from the cache or allocate a block in which to store it
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* - we return:
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* -ENOMEM - out of memory, nothing done
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* -ERESTARTSYS - interrupted
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* -ENOBUFS - no backing object available in which to cache the block
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* -ENODATA - no data available in the backing object for this block
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* 0 - dispatched a read - it'll call end_io_func() when finished
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*/
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int __fscache_read_or_alloc_page(struct fscache_cookie *cookie,
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struct page *page,
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fscache_rw_complete_t end_io_func,
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void *context,
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gfp_t gfp)
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{
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struct fscache_retrieval *op;
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struct fscache_object *object;
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int ret;
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_enter("%p,%p,,,", cookie, page);
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fscache_stat(&fscache_n_retrievals);
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if (hlist_empty(&cookie->backing_objects))
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goto nobufs;
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ASSERTCMP(cookie->def->type, !=, FSCACHE_COOKIE_TYPE_INDEX);
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ASSERTCMP(page, !=, NULL);
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if (fscache_wait_for_deferred_lookup(cookie) < 0)
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return -ERESTARTSYS;
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op = fscache_alloc_retrieval(page->mapping, end_io_func, context);
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if (!op) {
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_leave(" = -ENOMEM");
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return -ENOMEM;
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}
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fscache_set_op_name(&op->op, "RetrRA1");
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spin_lock(&cookie->lock);
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if (hlist_empty(&cookie->backing_objects))
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goto nobufs_unlock;
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object = hlist_entry(cookie->backing_objects.first,
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struct fscache_object, cookie_link);
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ASSERTCMP(object->state, >, FSCACHE_OBJECT_LOOKING_UP);
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atomic_inc(&object->n_reads);
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set_bit(FSCACHE_OP_DEC_READ_CNT, &op->op.flags);
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if (fscache_submit_op(object, &op->op) < 0)
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goto nobufs_unlock;
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spin_unlock(&cookie->lock);
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fscache_stat(&fscache_n_retrieval_ops);
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/* pin the netfs read context in case we need to do the actual netfs
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* read because we've encountered a cache read failure */
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fscache_get_context(object->cookie, op->context);
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/* we wait for the operation to become active, and then process it
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* *here*, in this thread, and not in the thread pool */
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ret = fscache_wait_for_retrieval_activation(
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object, op,
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__fscache_stat(&fscache_n_retrieval_op_waits),
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__fscache_stat(&fscache_n_retrievals_object_dead));
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if (ret < 0)
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goto error;
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/* ask the cache to honour the operation */
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if (test_bit(FSCACHE_COOKIE_NO_DATA_YET, &object->cookie->flags)) {
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fscache_stat(&fscache_n_cop_allocate_page);
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ret = object->cache->ops->allocate_page(op, page, gfp);
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fscache_stat_d(&fscache_n_cop_allocate_page);
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if (ret == 0)
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ret = -ENODATA;
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} else {
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fscache_stat(&fscache_n_cop_read_or_alloc_page);
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ret = object->cache->ops->read_or_alloc_page(op, page, gfp);
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fscache_stat_d(&fscache_n_cop_read_or_alloc_page);
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}
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error:
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if (ret == -ENOMEM)
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fscache_stat(&fscache_n_retrievals_nomem);
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else if (ret == -ERESTARTSYS)
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fscache_stat(&fscache_n_retrievals_intr);
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else if (ret == -ENODATA)
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fscache_stat(&fscache_n_retrievals_nodata);
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else if (ret < 0)
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fscache_stat(&fscache_n_retrievals_nobufs);
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else
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fscache_stat(&fscache_n_retrievals_ok);
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fscache_put_retrieval(op);
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_leave(" = %d", ret);
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return ret;
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nobufs_unlock:
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spin_unlock(&cookie->lock);
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kfree(op);
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nobufs:
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fscache_stat(&fscache_n_retrievals_nobufs);
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_leave(" = -ENOBUFS");
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return -ENOBUFS;
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}
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EXPORT_SYMBOL(__fscache_read_or_alloc_page);
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/*
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* read a list of page from the cache or allocate a block in which to store
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* them
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* - we return:
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* -ENOMEM - out of memory, some pages may be being read
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* -ERESTARTSYS - interrupted, some pages may be being read
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* -ENOBUFS - no backing object or space available in which to cache any
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* pages not being read
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* -ENODATA - no data available in the backing object for some or all of
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* the pages
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* 0 - dispatched a read on all pages
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*
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* end_io_func() will be called for each page read from the cache as it is
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* finishes being read
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*
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* any pages for which a read is dispatched will be removed from pages and
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* nr_pages
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*/
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int __fscache_read_or_alloc_pages(struct fscache_cookie *cookie,
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struct address_space *mapping,
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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;
|
|
int ret;
|
|
|
|
_enter("%p,,%d,,,", cookie, *nr_pages);
|
|
|
|
fscache_stat(&fscache_n_retrievals);
|
|
|
|
if (hlist_empty(&cookie->backing_objects))
|
|
goto nobufs;
|
|
|
|
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(mapping, end_io_func, context);
|
|
if (!op)
|
|
return -ENOMEM;
|
|
fscache_set_op_name(&op->op, "RetrRAN");
|
|
|
|
spin_lock(&cookie->lock);
|
|
|
|
if (hlist_empty(&cookie->backing_objects))
|
|
goto nobufs_unlock;
|
|
object = hlist_entry(cookie->backing_objects.first,
|
|
struct fscache_object, cookie_link);
|
|
|
|
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;
|
|
spin_unlock(&cookie->lock);
|
|
|
|
fscache_stat(&fscache_n_retrieval_ops);
|
|
|
|
/* pin the netfs read context in case we need to do the actual netfs
|
|
* read because we've encountered a cache read failure */
|
|
fscache_get_context(object->cookie, op->context);
|
|
|
|
/* 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_retrieval_activation(
|
|
object, 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:
|
|
spin_unlock(&cookie->lock);
|
|
kfree(op);
|
|
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;
|
|
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 (fscache_wait_for_deferred_lookup(cookie) < 0)
|
|
return -ERESTARTSYS;
|
|
|
|
op = fscache_alloc_retrieval(page->mapping, NULL, NULL);
|
|
if (!op)
|
|
return -ENOMEM;
|
|
fscache_set_op_name(&op->op, "RetrAL1");
|
|
|
|
spin_lock(&cookie->lock);
|
|
|
|
if (hlist_empty(&cookie->backing_objects))
|
|
goto nobufs_unlock;
|
|
object = hlist_entry(cookie->backing_objects.first,
|
|
struct fscache_object, cookie_link);
|
|
|
|
if (fscache_submit_op(object, &op->op) < 0)
|
|
goto nobufs_unlock;
|
|
spin_unlock(&cookie->lock);
|
|
|
|
fscache_stat(&fscache_n_alloc_ops);
|
|
|
|
ret = fscache_wait_for_retrieval_activation(
|
|
object, 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:
|
|
spin_unlock(&cookie->lock);
|
|
kfree(op);
|
|
nobufs:
|
|
fscache_stat(&fscache_n_allocs_nobufs);
|
|
_leave(" = -ENOBUFS");
|
|
return -ENOBUFS;
|
|
}
|
|
EXPORT_SYMBOL(__fscache_alloc_page);
|
|
|
|
/*
|
|
* 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));
|
|
|
|
fscache_set_op_state(&op->op, "GetPage");
|
|
|
|
spin_lock(&object->lock);
|
|
cookie = object->cookie;
|
|
|
|
if (!fscache_object_is_active(object) || !cookie) {
|
|
spin_unlock(&object->lock);
|
|
_leave("");
|
|
return;
|
|
}
|
|
|
|
spin_lock(&cookie->stores_lock);
|
|
|
|
fscache_stat(&fscache_n_store_calls);
|
|
|
|
/* find a page to store */
|
|
page = NULL;
|
|
n = radix_tree_gang_lookup_tag(&cookie->stores, results, 0, 1,
|
|
FSCACHE_COOKIE_PENDING_TAG);
|
|
if (n != 1)
|
|
goto superseded;
|
|
page = results[0];
|
|
_debug("gang %d [%lx]", n, page->index);
|
|
if (page->index > op->store_limit) {
|
|
fscache_stat(&fscache_n_store_pages_over_limit);
|
|
goto superseded;
|
|
}
|
|
|
|
radix_tree_tag_set(&cookie->stores, page->index,
|
|
FSCACHE_COOKIE_STORING_TAG);
|
|
radix_tree_tag_clear(&cookie->stores, page->index,
|
|
FSCACHE_COOKIE_PENDING_TAG);
|
|
|
|
spin_unlock(&cookie->stores_lock);
|
|
spin_unlock(&object->lock);
|
|
|
|
fscache_set_op_state(&op->op, "Store");
|
|
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);
|
|
fscache_set_op_state(&op->op, "EndWrite");
|
|
fscache_end_page_write(object, page);
|
|
if (ret < 0) {
|
|
fscache_set_op_state(&op->op, "Abort");
|
|
fscache_abort_object(object);
|
|
} else {
|
|
fscache_enqueue_operation(&op->op);
|
|
}
|
|
|
|
_leave("");
|
|
return;
|
|
|
|
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);
|
|
_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 (set FSCACHE_COOKIE_PENDING_FILL and queue deferred
|
|
* fill op)
|
|
*
|
|
* (b) writes deferred till post-creation (mark page for writing and
|
|
* return immediately)
|
|
*
|
|
* (2) negative lookup, object created, initial fill being made from netfs
|
|
* (FSCACHE_COOKIE_INITIAL_FILL is set)
|
|
*
|
|
* (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,
|
|
gfp_t gfp)
|
|
{
|
|
struct fscache_storage *op;
|
|
struct fscache_object *object;
|
|
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);
|
|
|
|
op = kzalloc(sizeof(*op), GFP_NOIO);
|
|
if (!op)
|
|
goto nomem;
|
|
|
|
fscache_operation_init(&op->op, fscache_release_write_op);
|
|
fscache_operation_init_slow(&op->op, fscache_write_op);
|
|
op->op.flags = FSCACHE_OP_SLOW | (1 << FSCACHE_OP_WAITING);
|
|
fscache_set_op_name(&op->op, "Write1");
|
|
|
|
ret = radix_tree_preload(gfp & ~__GFP_HIGHMEM);
|
|
if (ret < 0)
|
|
goto nomem_free;
|
|
|
|
ret = -ENOBUFS;
|
|
spin_lock(&cookie->lock);
|
|
|
|
if (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;
|
|
|
|
/* add the page to the pending-storage radix tree on the backing
|
|
* object */
|
|
spin_lock(&object->lock);
|
|
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;
|
|
}
|
|
|
|
radix_tree_tag_set(&cookie->stores, page->index,
|
|
FSCACHE_COOKIE_PENDING_TAG);
|
|
page_cache_get(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;
|
|
|
|
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 slow 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();
|
|
kfree(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);
|
|
spin_unlock(&cookie->stores_lock);
|
|
page_cache_release(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();
|
|
kfree(op);
|
|
fscache_stat(&fscache_n_stores_nobufs);
|
|
_leave(" = -ENOBUFS");
|
|
return -ENOBUFS;
|
|
|
|
nomem_free:
|
|
kfree(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;
|
|
|
|
/* 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_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)
|
|
{
|
|
struct fscache_cookie *cookie = op->op.object->cookie;
|
|
unsigned long loop;
|
|
|
|
#ifdef CONFIG_FSCACHE_STATS
|
|
atomic_add(pagevec->nr, &fscache_n_marks);
|
|
#endif
|
|
|
|
for (loop = 0; loop < pagevec->nr; loop++) {
|
|
struct page *page = pagevec->pages[loop];
|
|
|
|
_debug("- mark %p{%lx}", page, page->index);
|
|
if (TestSetPageFsCache(page)) {
|
|
static bool once_only;
|
|
if (!once_only) {
|
|
once_only = true;
|
|
printk(KERN_WARNING "FS-Cache:"
|
|
" Cookie type %s marked page %lx"
|
|
" multiple times\n",
|
|
cookie->def->name, page->index);
|
|
}
|
|
}
|
|
}
|
|
|
|
if (cookie->def->mark_pages_cached)
|
|
cookie->def->mark_pages_cached(cookie->netfs_data,
|
|
op->mapping, pagevec);
|
|
pagevec_reinit(pagevec);
|
|
}
|
|
EXPORT_SYMBOL(fscache_mark_pages_cached);
|