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1248 lines
33 KiB
1248 lines
33 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
|
/* 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 ([email protected]) |
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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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trace_fscache_check_page(cookie, page, val, 0); |
|
|
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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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wait_queue_head_t *wq = bit_waitqueue(&cookie->flags, 0); |
|
|
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trace_fscache_page(cookie, page, fscache_page_write_wait); |
|
|
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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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* wait for a page to finish being written to the cache. Put a timeout here |
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* since we might be called recursively via parent fs. |
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*/ |
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static |
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bool release_page_wait_timeout(struct fscache_cookie *cookie, struct page *page) |
|
{ |
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wait_queue_head_t *wq = bit_waitqueue(&cookie->flags, 0); |
|
|
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return wait_event_timeout(*wq, !__fscache_check_page_write(cookie, page), |
|
HZ); |
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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_DIRECT_RECLAIM is flagged |
|
*/ |
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bool __fscache_maybe_release_page(struct fscache_cookie *cookie, |
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struct page *page, |
|
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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trace_fscache_page(cookie, page, fscache_page_maybe_release); |
|
|
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try_again: |
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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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/* 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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|
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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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trace_fscache_page(cookie, page, fscache_page_radix_delete); |
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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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trace_fscache_wake_cookie(cookie); |
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if (xpage) |
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put_page(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 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 |
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* too. */ |
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if (!(gfp & __GFP_DIRECT_RECLAIM) || !(gfp & __GFP_FS)) { |
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fscache_stat(&fscache_n_store_vmscan_busy); |
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return false; |
|
} |
|
|
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fscache_stat(&fscache_n_store_vmscan_wait); |
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if (!release_page_wait_timeout(cookie, page)) |
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_debug("fscache writeout timeout page: %p{%lx}", |
|
page, page->index); |
|
|
|
gfp &= ~__GFP_DIRECT_RECLAIM; |
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goto try_again; |
|
} |
|
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, *val; |
|
|
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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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trace_fscache_page(cookie, page, fscache_page_radix_clear_store); |
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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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trace_fscache_page(cookie, page, fscache_page_radix_delete); |
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trace_fscache_page(cookie, page, fscache_page_write_end); |
|
|
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val = radix_tree_lookup(&cookie->stores, page->index); |
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trace_fscache_check_page(cookie, page, val, 1); |
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} else { |
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trace_fscache_page(cookie, page, fscache_page_write_end_pend); |
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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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trace_fscache_wake_cookie(cookie); |
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} else { |
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trace_fscache_page(cookie, page, fscache_page_write_end_noc); |
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} |
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spin_unlock(&object->lock); |
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if (xpage) |
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put_page(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_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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if (ret < 0) |
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fscache_abort_object(object); |
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fscache_op_complete(op, ret < 0); |
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} else { |
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fscache_op_complete(op, true); |
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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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bool wake_cookie = false; |
|
|
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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(cookie, op, fscache_attr_changed_op, NULL, NULL); |
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trace_fscache_page_op(cookie, NULL, op, fscache_page_op_attr_changed); |
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op->flags = FSCACHE_OP_ASYNC | |
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(1 << FSCACHE_OP_EXCLUSIVE) | |
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(1 << FSCACHE_OP_UNUSE_COOKIE); |
|
|
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spin_lock(&cookie->lock); |
|
|
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if (!fscache_cookie_enabled(cookie) || |
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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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__fscache_use_cookie(cookie); |
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if (fscache_submit_exclusive_op(object, op) < 0) |
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goto nobufs_dec; |
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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_dec: |
|
wake_cookie = __fscache_unuse_cookie(cookie); |
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nobufs: |
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spin_unlock(&cookie->lock); |
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fscache_put_operation(op); |
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if (wake_cookie) |
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__fscache_wake_unused_cookie(cookie); |
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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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EXPORT_SYMBOL(__fscache_attr_changed); |
|
|
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/* |
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* Handle cancellation of a pending retrieval op |
|
*/ |
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static void fscache_do_cancel_retrieval(struct fscache_operation *_op) |
|
{ |
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struct fscache_retrieval *op = |
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container_of(_op, struct fscache_retrieval, op); |
|
|
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atomic_set(&op->n_pages, 0); |
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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 = |
|
container_of(_op, struct fscache_retrieval, op); |
|
|
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_enter("{OP%x}", op->op.debug_id); |
|
|
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ASSERTIFCMP(op->op.state != FSCACHE_OP_ST_INITIALISED, |
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atomic_read(&op->n_pages), ==, 0); |
|
|
|
fscache_hist(fscache_retrieval_histogram, op->start_time); |
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if (op->context) |
|
fscache_put_context(op->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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static struct fscache_retrieval *fscache_alloc_retrieval( |
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struct fscache_cookie *cookie, |
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struct address_space *mapping, |
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fscache_rw_complete_t end_io_func, |
|
void *context) |
|
{ |
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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; |
|
} |
|
|
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fscache_operation_init(cookie, &op->op, NULL, |
|
fscache_do_cancel_retrieval, |
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fscache_release_retrieval_op); |
|
op->op.flags = FSCACHE_OP_MYTHREAD | |
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(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);
|
|
|