v4.19.13 snapshot.
diff --git a/fs/fscache/page.c b/fs/fscache/page.c
new file mode 100644
index 0000000..111349f
--- /dev/null
+++ b/fs/fscache/page.c
@@ -0,0 +1,1252 @@
+/* Cache page management and data I/O routines
+ *
+ * Copyright (C) 2004-2008 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#define FSCACHE_DEBUG_LEVEL PAGE
+#include <linux/module.h>
+#include <linux/fscache-cache.h>
+#include <linux/buffer_head.h>
+#include <linux/pagevec.h>
+#include <linux/slab.h>
+#include "internal.h"
+
+/*
+ * check to see if a page is being written to the cache
+ */
+bool __fscache_check_page_write(struct fscache_cookie *cookie, struct page *page)
+{
+ void *val;
+
+ rcu_read_lock();
+ val = radix_tree_lookup(&cookie->stores, page->index);
+ rcu_read_unlock();
+ trace_fscache_check_page(cookie, page, val, 0);
+
+ return val != NULL;
+}
+EXPORT_SYMBOL(__fscache_check_page_write);
+
+/*
+ * wait for a page to finish being written to the cache
+ */
+void __fscache_wait_on_page_write(struct fscache_cookie *cookie, struct page *page)
+{
+ wait_queue_head_t *wq = bit_waitqueue(&cookie->flags, 0);
+
+ trace_fscache_page(cookie, page, fscache_page_write_wait);
+
+ wait_event(*wq, !__fscache_check_page_write(cookie, page));
+}
+EXPORT_SYMBOL(__fscache_wait_on_page_write);
+
+/*
+ * wait for a page to finish being written to the cache. Put a timeout here
+ * since we might be called recursively via parent fs.
+ */
+static
+bool release_page_wait_timeout(struct fscache_cookie *cookie, struct page *page)
+{
+ wait_queue_head_t *wq = bit_waitqueue(&cookie->flags, 0);
+
+ return wait_event_timeout(*wq, !__fscache_check_page_write(cookie, page),
+ HZ);
+}
+
+/*
+ * decide whether a page can be released, possibly by cancelling a store to it
+ * - we're allowed to sleep if __GFP_DIRECT_RECLAIM is flagged
+ */
+bool __fscache_maybe_release_page(struct fscache_cookie *cookie,
+ struct page *page,
+ gfp_t gfp)
+{
+ struct page *xpage;
+ void *val;
+
+ _enter("%p,%p,%x", cookie, page, gfp);
+
+ trace_fscache_page(cookie, page, fscache_page_maybe_release);
+
+try_again:
+ rcu_read_lock();
+ val = radix_tree_lookup(&cookie->stores, page->index);
+ if (!val) {
+ rcu_read_unlock();
+ fscache_stat(&fscache_n_store_vmscan_not_storing);
+ __fscache_uncache_page(cookie, page);
+ return true;
+ }
+
+ /* see if the page is actually undergoing storage - if so we can't get
+ * rid of it till the cache has finished with it */
+ if (radix_tree_tag_get(&cookie->stores, page->index,
+ FSCACHE_COOKIE_STORING_TAG)) {
+ rcu_read_unlock();
+ goto page_busy;
+ }
+
+ /* the page is pending storage, so we attempt to cancel the store and
+ * discard the store request so that the page can be reclaimed */
+ spin_lock(&cookie->stores_lock);
+ rcu_read_unlock();
+
+ if (radix_tree_tag_get(&cookie->stores, page->index,
+ FSCACHE_COOKIE_STORING_TAG)) {
+ /* the page started to undergo storage whilst we were looking,
+ * so now we can only wait or return */
+ spin_unlock(&cookie->stores_lock);
+ goto page_busy;
+ }
+
+ xpage = radix_tree_delete(&cookie->stores, page->index);
+ trace_fscache_page(cookie, page, fscache_page_radix_delete);
+ spin_unlock(&cookie->stores_lock);
+
+ if (xpage) {
+ fscache_stat(&fscache_n_store_vmscan_cancelled);
+ fscache_stat(&fscache_n_store_radix_deletes);
+ ASSERTCMP(xpage, ==, page);
+ } else {
+ fscache_stat(&fscache_n_store_vmscan_gone);
+ }
+
+ wake_up_bit(&cookie->flags, 0);
+ trace_fscache_wake_cookie(cookie);
+ if (xpage)
+ put_page(xpage);
+ __fscache_uncache_page(cookie, page);
+ return true;
+
+page_busy:
+ /* We will wait here if we're allowed to, but that could deadlock the
+ * allocator as the work threads writing to the cache may all end up
+ * sleeping on memory allocation, so we may need to impose a timeout
+ * too. */
+ if (!(gfp & __GFP_DIRECT_RECLAIM) || !(gfp & __GFP_FS)) {
+ fscache_stat(&fscache_n_store_vmscan_busy);
+ return false;
+ }
+
+ fscache_stat(&fscache_n_store_vmscan_wait);
+ if (!release_page_wait_timeout(cookie, page))
+ _debug("fscache writeout timeout page: %p{%lx}",
+ page, page->index);
+
+ gfp &= ~__GFP_DIRECT_RECLAIM;
+ goto try_again;
+}
+EXPORT_SYMBOL(__fscache_maybe_release_page);
+
+/*
+ * note that a page has finished being written to the cache
+ */
+static void fscache_end_page_write(struct fscache_object *object,
+ struct page *page)
+{
+ struct fscache_cookie *cookie;
+ struct page *xpage = NULL, *val;
+
+ spin_lock(&object->lock);
+ cookie = object->cookie;
+ if (cookie) {
+ /* delete the page from the tree if it is now no longer
+ * pending */
+ spin_lock(&cookie->stores_lock);
+ radix_tree_tag_clear(&cookie->stores, page->index,
+ FSCACHE_COOKIE_STORING_TAG);
+ trace_fscache_page(cookie, page, fscache_page_radix_clear_store);
+ if (!radix_tree_tag_get(&cookie->stores, page->index,
+ FSCACHE_COOKIE_PENDING_TAG)) {
+ fscache_stat(&fscache_n_store_radix_deletes);
+ xpage = radix_tree_delete(&cookie->stores, page->index);
+ trace_fscache_page(cookie, page, fscache_page_radix_delete);
+ trace_fscache_page(cookie, page, fscache_page_write_end);
+
+ val = radix_tree_lookup(&cookie->stores, page->index);
+ trace_fscache_check_page(cookie, page, val, 1);
+ } else {
+ trace_fscache_page(cookie, page, fscache_page_write_end_pend);
+ }
+ spin_unlock(&cookie->stores_lock);
+ wake_up_bit(&cookie->flags, 0);
+ trace_fscache_wake_cookie(cookie);
+ } else {
+ trace_fscache_page(cookie, page, fscache_page_write_end_noc);
+ }
+ spin_unlock(&object->lock);
+ if (xpage)
+ put_page(xpage);
+}
+
+/*
+ * actually apply the changed attributes to a cache object
+ */
+static void fscache_attr_changed_op(struct fscache_operation *op)
+{
+ struct fscache_object *object = op->object;
+ int ret;
+
+ _enter("{OBJ%x OP%x}", object->debug_id, op->debug_id);
+
+ fscache_stat(&fscache_n_attr_changed_calls);
+
+ if (fscache_object_is_active(object)) {
+ fscache_stat(&fscache_n_cop_attr_changed);
+ ret = object->cache->ops->attr_changed(object);
+ fscache_stat_d(&fscache_n_cop_attr_changed);
+ if (ret < 0)
+ fscache_abort_object(object);
+ fscache_op_complete(op, ret < 0);
+ } else {
+ fscache_op_complete(op, true);
+ }
+
+ _leave("");
+}
+
+/*
+ * notification that the attributes on an object have changed
+ */
+int __fscache_attr_changed(struct fscache_cookie *cookie)
+{
+ struct fscache_operation *op;
+ struct fscache_object *object;
+ bool wake_cookie = false;
+
+ _enter("%p", cookie);
+
+ ASSERTCMP(cookie->def->type, !=, FSCACHE_COOKIE_TYPE_INDEX);
+
+ fscache_stat(&fscache_n_attr_changed);
+
+ op = kzalloc(sizeof(*op), GFP_KERNEL);
+ if (!op) {
+ fscache_stat(&fscache_n_attr_changed_nomem);
+ _leave(" = -ENOMEM");
+ return -ENOMEM;
+ }
+
+ fscache_operation_init(cookie, op, fscache_attr_changed_op, NULL, NULL);
+ trace_fscache_page_op(cookie, NULL, op, fscache_page_op_attr_changed);
+ op->flags = FSCACHE_OP_ASYNC |
+ (1 << FSCACHE_OP_EXCLUSIVE) |
+ (1 << FSCACHE_OP_UNUSE_COOKIE);
+
+ spin_lock(&cookie->lock);
+
+ if (!fscache_cookie_enabled(cookie) ||
+ hlist_empty(&cookie->backing_objects))
+ goto nobufs;
+ object = hlist_entry(cookie->backing_objects.first,
+ struct fscache_object, cookie_link);
+
+ __fscache_use_cookie(cookie);
+ if (fscache_submit_exclusive_op(object, op) < 0)
+ goto nobufs_dec;
+ spin_unlock(&cookie->lock);
+ fscache_stat(&fscache_n_attr_changed_ok);
+ fscache_put_operation(op);
+ _leave(" = 0");
+ return 0;
+
+nobufs_dec:
+ wake_cookie = __fscache_unuse_cookie(cookie);
+nobufs:
+ spin_unlock(&cookie->lock);
+ fscache_put_operation(op);
+ if (wake_cookie)
+ __fscache_wake_unused_cookie(cookie);
+ fscache_stat(&fscache_n_attr_changed_nobufs);
+ _leave(" = %d", -ENOBUFS);
+ return -ENOBUFS;
+}
+EXPORT_SYMBOL(__fscache_attr_changed);
+
+/*
+ * Handle cancellation of a pending retrieval op
+ */
+static void fscache_do_cancel_retrieval(struct fscache_operation *_op)
+{
+ struct fscache_retrieval *op =
+ container_of(_op, struct fscache_retrieval, op);
+
+ atomic_set(&op->n_pages, 0);
+}
+
+/*
+ * release a retrieval op reference
+ */
+static void fscache_release_retrieval_op(struct fscache_operation *_op)
+{
+ struct fscache_retrieval *op =
+ container_of(_op, struct fscache_retrieval, op);
+
+ _enter("{OP%x}", op->op.debug_id);
+
+ ASSERTIFCMP(op->op.state != FSCACHE_OP_ST_INITIALISED,
+ atomic_read(&op->n_pages), ==, 0);
+
+ fscache_hist(fscache_retrieval_histogram, op->start_time);
+ if (op->context)
+ fscache_put_context(op->cookie, op->context);
+
+ _leave("");
+}
+
+/*
+ * allocate a retrieval op
+ */
+static struct fscache_retrieval *fscache_alloc_retrieval(
+ struct fscache_cookie *cookie,
+ struct address_space *mapping,
+ fscache_rw_complete_t end_io_func,
+ void *context)
+{
+ struct fscache_retrieval *op;
+
+ /* allocate a retrieval operation and attempt to submit it */
+ op = kzalloc(sizeof(*op), GFP_NOIO);
+ if (!op) {
+ fscache_stat(&fscache_n_retrievals_nomem);
+ return NULL;
+ }
+
+ fscache_operation_init(cookie, &op->op, NULL,
+ fscache_do_cancel_retrieval,
+ fscache_release_retrieval_op);
+ op->op.flags = FSCACHE_OP_MYTHREAD |
+ (1UL << FSCACHE_OP_WAITING) |
+ (1UL << FSCACHE_OP_UNUSE_COOKIE);
+ op->cookie = cookie;
+ op->mapping = mapping;
+ op->end_io_func = end_io_func;
+ op->context = context;
+ op->start_time = jiffies;
+ INIT_LIST_HEAD(&op->to_do);
+
+ /* Pin the netfs read context in case we need to do the actual netfs
+ * read because we've encountered a cache read failure.
+ */
+ if (context)
+ fscache_get_context(op->cookie, context);
+ return op;
+}
+
+/*
+ * wait for a deferred lookup to complete
+ */
+int fscache_wait_for_deferred_lookup(struct fscache_cookie *cookie)
+{
+ unsigned long jif;
+
+ _enter("");
+
+ if (!test_bit(FSCACHE_COOKIE_LOOKING_UP, &cookie->flags)) {
+ _leave(" = 0 [imm]");
+ return 0;
+ }
+
+ fscache_stat(&fscache_n_retrievals_wait);
+
+ jif = jiffies;
+ if (wait_on_bit(&cookie->flags, FSCACHE_COOKIE_LOOKING_UP,
+ TASK_INTERRUPTIBLE) != 0) {
+ fscache_stat(&fscache_n_retrievals_intr);
+ _leave(" = -ERESTARTSYS");
+ return -ERESTARTSYS;
+ }
+
+ ASSERT(!test_bit(FSCACHE_COOKIE_LOOKING_UP, &cookie->flags));
+
+ smp_rmb();
+ fscache_hist(fscache_retrieval_delay_histogram, jif);
+ _leave(" = 0 [dly]");
+ return 0;
+}
+
+/*
+ * wait for an object to become active (or dead)
+ */
+int fscache_wait_for_operation_activation(struct fscache_object *object,
+ struct fscache_operation *op,
+ atomic_t *stat_op_waits,
+ atomic_t *stat_object_dead)
+{
+ int ret;
+
+ if (!test_bit(FSCACHE_OP_WAITING, &op->flags))
+ goto check_if_dead;
+
+ _debug(">>> WT");
+ if (stat_op_waits)
+ fscache_stat(stat_op_waits);
+ if (wait_on_bit(&op->flags, FSCACHE_OP_WAITING,
+ TASK_INTERRUPTIBLE) != 0) {
+ trace_fscache_op(object->cookie, op, fscache_op_signal);
+ ret = fscache_cancel_op(op, false);
+ if (ret == 0)
+ return -ERESTARTSYS;
+
+ /* it's been removed from the pending queue by another party,
+ * so we should get to run shortly */
+ wait_on_bit(&op->flags, FSCACHE_OP_WAITING,
+ TASK_UNINTERRUPTIBLE);
+ }
+ _debug("<<< GO");
+
+check_if_dead:
+ if (op->state == FSCACHE_OP_ST_CANCELLED) {
+ if (stat_object_dead)
+ fscache_stat(stat_object_dead);
+ _leave(" = -ENOBUFS [cancelled]");
+ return -ENOBUFS;
+ }
+ if (unlikely(fscache_object_is_dying(object) ||
+ fscache_cache_is_broken(object))) {
+ enum fscache_operation_state state = op->state;
+ trace_fscache_op(object->cookie, op, fscache_op_signal);
+ fscache_cancel_op(op, true);
+ if (stat_object_dead)
+ fscache_stat(stat_object_dead);
+ _leave(" = -ENOBUFS [obj dead %d]", state);
+ return -ENOBUFS;
+ }
+ return 0;
+}
+
+/*
+ * read a page from the cache or allocate a block in which to store it
+ * - we return:
+ * -ENOMEM - out of memory, nothing done
+ * -ERESTARTSYS - interrupted
+ * -ENOBUFS - no backing object available in which to cache the block
+ * -ENODATA - no data available in the backing object for this block
+ * 0 - dispatched a read - it'll call end_io_func() when finished
+ */
+int __fscache_read_or_alloc_page(struct fscache_cookie *cookie,
+ struct page *page,
+ fscache_rw_complete_t end_io_func,
+ void *context,
+ gfp_t gfp)
+{
+ struct fscache_retrieval *op;
+ struct fscache_object *object;
+ bool wake_cookie = false;
+ int ret;
+
+ _enter("%p,%p,,,", cookie, page);
+
+ fscache_stat(&fscache_n_retrievals);
+
+ if (hlist_empty(&cookie->backing_objects))
+ goto nobufs;
+
+ if (test_bit(FSCACHE_COOKIE_INVALIDATING, &cookie->flags)) {
+ _leave(" = -ENOBUFS [invalidating]");
+ return -ENOBUFS;
+ }
+
+ ASSERTCMP(cookie->def->type, !=, FSCACHE_COOKIE_TYPE_INDEX);
+ ASSERTCMP(page, !=, NULL);
+
+ if (fscache_wait_for_deferred_lookup(cookie) < 0)
+ return -ERESTARTSYS;
+
+ op = fscache_alloc_retrieval(cookie, page->mapping,
+ end_io_func, context);
+ if (!op) {
+ _leave(" = -ENOMEM");
+ return -ENOMEM;
+ }
+ atomic_set(&op->n_pages, 1);
+ trace_fscache_page_op(cookie, page, &op->op, fscache_page_op_retr_one);
+
+ spin_lock(&cookie->lock);
+
+ if (!fscache_cookie_enabled(cookie) ||
+ hlist_empty(&cookie->backing_objects))
+ goto nobufs_unlock;
+ object = hlist_entry(cookie->backing_objects.first,
+ struct fscache_object, cookie_link);
+
+ ASSERT(test_bit(FSCACHE_OBJECT_IS_LOOKED_UP, &object->flags));
+
+ __fscache_use_cookie(cookie);
+ atomic_inc(&object->n_reads);
+ __set_bit(FSCACHE_OP_DEC_READ_CNT, &op->op.flags);
+
+ if (fscache_submit_op(object, &op->op) < 0)
+ goto nobufs_unlock_dec;
+ spin_unlock(&cookie->lock);
+
+ fscache_stat(&fscache_n_retrieval_ops);
+
+ /* we wait for the operation to become active, and then process it
+ * *here*, in this thread, and not in the thread pool */
+ ret = fscache_wait_for_operation_activation(
+ object, &op->op,
+ __fscache_stat(&fscache_n_retrieval_op_waits),
+ __fscache_stat(&fscache_n_retrievals_object_dead));
+ if (ret < 0)
+ goto error;
+
+ /* ask the cache to honour the operation */
+ if (test_bit(FSCACHE_COOKIE_NO_DATA_YET, &object->cookie->flags)) {
+ fscache_stat(&fscache_n_cop_allocate_page);
+ ret = object->cache->ops->allocate_page(op, page, gfp);
+ fscache_stat_d(&fscache_n_cop_allocate_page);
+ if (ret == 0)
+ ret = -ENODATA;
+ } else {
+ fscache_stat(&fscache_n_cop_read_or_alloc_page);
+ ret = object->cache->ops->read_or_alloc_page(op, page, gfp);
+ fscache_stat_d(&fscache_n_cop_read_or_alloc_page);
+ }
+
+error:
+ if (ret == -ENOMEM)
+ fscache_stat(&fscache_n_retrievals_nomem);
+ else if (ret == -ERESTARTSYS)
+ fscache_stat(&fscache_n_retrievals_intr);
+ else if (ret == -ENODATA)
+ fscache_stat(&fscache_n_retrievals_nodata);
+ else if (ret < 0)
+ fscache_stat(&fscache_n_retrievals_nobufs);
+ else
+ fscache_stat(&fscache_n_retrievals_ok);
+
+ fscache_put_retrieval(op);
+ _leave(" = %d", ret);
+ return ret;
+
+nobufs_unlock_dec:
+ atomic_dec(&object->n_reads);
+ wake_cookie = __fscache_unuse_cookie(cookie);
+nobufs_unlock:
+ spin_unlock(&cookie->lock);
+ if (wake_cookie)
+ __fscache_wake_unused_cookie(cookie);
+ fscache_put_retrieval(op);
+nobufs:
+ fscache_stat(&fscache_n_retrievals_nobufs);
+ _leave(" = -ENOBUFS");
+ return -ENOBUFS;
+}
+EXPORT_SYMBOL(__fscache_read_or_alloc_page);
+
+/*
+ * read a list of page from the cache or allocate a block in which to store
+ * them
+ * - we return:
+ * -ENOMEM - out of memory, some pages may be being read
+ * -ERESTARTSYS - interrupted, some pages may be being read
+ * -ENOBUFS - no backing object or space available in which to cache any
+ * pages not being read
+ * -ENODATA - no data available in the backing object for some or all of
+ * the pages
+ * 0 - dispatched a read on all pages
+ *
+ * end_io_func() will be called for each page read from the cache as it is
+ * finishes being read
+ *
+ * any pages for which a read is dispatched will be removed from pages and
+ * nr_pages
+ */
+int __fscache_read_or_alloc_pages(struct fscache_cookie *cookie,
+ struct address_space *mapping,
+ struct list_head *pages,
+ unsigned *nr_pages,
+ fscache_rw_complete_t end_io_func,
+ void *context,
+ gfp_t gfp)
+{
+ struct fscache_retrieval *op;
+ struct fscache_object *object;
+ bool wake_cookie = false;
+ int ret;
+
+ _enter("%p,,%d,,,", cookie, *nr_pages);
+
+ fscache_stat(&fscache_n_retrievals);
+
+ if (hlist_empty(&cookie->backing_objects))
+ goto nobufs;
+
+ if (test_bit(FSCACHE_COOKIE_INVALIDATING, &cookie->flags)) {
+ _leave(" = -ENOBUFS [invalidating]");
+ return -ENOBUFS;
+ }
+
+ ASSERTCMP(cookie->def->type, !=, FSCACHE_COOKIE_TYPE_INDEX);
+ ASSERTCMP(*nr_pages, >, 0);
+ ASSERT(!list_empty(pages));
+
+ if (fscache_wait_for_deferred_lookup(cookie) < 0)
+ return -ERESTARTSYS;
+
+ op = fscache_alloc_retrieval(cookie, mapping, end_io_func, context);
+ if (!op)
+ return -ENOMEM;
+ atomic_set(&op->n_pages, *nr_pages);
+ trace_fscache_page_op(cookie, NULL, &op->op, fscache_page_op_retr_multi);
+
+ spin_lock(&cookie->lock);
+
+ if (!fscache_cookie_enabled(cookie) ||
+ hlist_empty(&cookie->backing_objects))
+ goto nobufs_unlock;
+ object = hlist_entry(cookie->backing_objects.first,
+ struct fscache_object, cookie_link);
+
+ __fscache_use_cookie(cookie);
+ atomic_inc(&object->n_reads);
+ __set_bit(FSCACHE_OP_DEC_READ_CNT, &op->op.flags);
+
+ if (fscache_submit_op(object, &op->op) < 0)
+ goto nobufs_unlock_dec;
+ spin_unlock(&cookie->lock);
+
+ fscache_stat(&fscache_n_retrieval_ops);
+
+ /* we wait for the operation to become active, and then process it
+ * *here*, in this thread, and not in the thread pool */
+ ret = fscache_wait_for_operation_activation(
+ object, &op->op,
+ __fscache_stat(&fscache_n_retrieval_op_waits),
+ __fscache_stat(&fscache_n_retrievals_object_dead));
+ if (ret < 0)
+ goto error;
+
+ /* ask the cache to honour the operation */
+ if (test_bit(FSCACHE_COOKIE_NO_DATA_YET, &object->cookie->flags)) {
+ fscache_stat(&fscache_n_cop_allocate_pages);
+ ret = object->cache->ops->allocate_pages(
+ op, pages, nr_pages, gfp);
+ fscache_stat_d(&fscache_n_cop_allocate_pages);
+ } else {
+ fscache_stat(&fscache_n_cop_read_or_alloc_pages);
+ ret = object->cache->ops->read_or_alloc_pages(
+ op, pages, nr_pages, gfp);
+ fscache_stat_d(&fscache_n_cop_read_or_alloc_pages);
+ }
+
+error:
+ if (ret == -ENOMEM)
+ fscache_stat(&fscache_n_retrievals_nomem);
+ else if (ret == -ERESTARTSYS)
+ fscache_stat(&fscache_n_retrievals_intr);
+ else if (ret == -ENODATA)
+ fscache_stat(&fscache_n_retrievals_nodata);
+ else if (ret < 0)
+ fscache_stat(&fscache_n_retrievals_nobufs);
+ else
+ fscache_stat(&fscache_n_retrievals_ok);
+
+ fscache_put_retrieval(op);
+ _leave(" = %d", ret);
+ return ret;
+
+nobufs_unlock_dec:
+ atomic_dec(&object->n_reads);
+ wake_cookie = __fscache_unuse_cookie(cookie);
+nobufs_unlock:
+ spin_unlock(&cookie->lock);
+ fscache_put_retrieval(op);
+ if (wake_cookie)
+ __fscache_wake_unused_cookie(cookie);
+nobufs:
+ fscache_stat(&fscache_n_retrievals_nobufs);
+ _leave(" = -ENOBUFS");
+ return -ENOBUFS;
+}
+EXPORT_SYMBOL(__fscache_read_or_alloc_pages);
+
+/*
+ * allocate a block in the cache on which to store a page
+ * - we return:
+ * -ENOMEM - out of memory, nothing done
+ * -ERESTARTSYS - interrupted
+ * -ENOBUFS - no backing object available in which to cache the block
+ * 0 - block allocated
+ */
+int __fscache_alloc_page(struct fscache_cookie *cookie,
+ struct page *page,
+ gfp_t gfp)
+{
+ struct fscache_retrieval *op;
+ struct fscache_object *object;
+ bool wake_cookie = false;
+ int ret;
+
+ _enter("%p,%p,,,", cookie, page);
+
+ fscache_stat(&fscache_n_allocs);
+
+ if (hlist_empty(&cookie->backing_objects))
+ goto nobufs;
+
+ ASSERTCMP(cookie->def->type, !=, FSCACHE_COOKIE_TYPE_INDEX);
+ ASSERTCMP(page, !=, NULL);
+
+ if (test_bit(FSCACHE_COOKIE_INVALIDATING, &cookie->flags)) {
+ _leave(" = -ENOBUFS [invalidating]");
+ return -ENOBUFS;
+ }
+
+ if (fscache_wait_for_deferred_lookup(cookie) < 0)
+ return -ERESTARTSYS;
+
+ op = fscache_alloc_retrieval(cookie, page->mapping, NULL, NULL);
+ if (!op)
+ return -ENOMEM;
+ atomic_set(&op->n_pages, 1);
+ trace_fscache_page_op(cookie, page, &op->op, fscache_page_op_alloc_one);
+
+ spin_lock(&cookie->lock);
+
+ if (!fscache_cookie_enabled(cookie) ||
+ hlist_empty(&cookie->backing_objects))
+ goto nobufs_unlock;
+ object = hlist_entry(cookie->backing_objects.first,
+ struct fscache_object, cookie_link);
+
+ __fscache_use_cookie(cookie);
+ if (fscache_submit_op(object, &op->op) < 0)
+ goto nobufs_unlock_dec;
+ spin_unlock(&cookie->lock);
+
+ fscache_stat(&fscache_n_alloc_ops);
+
+ ret = fscache_wait_for_operation_activation(
+ object, &op->op,
+ __fscache_stat(&fscache_n_alloc_op_waits),
+ __fscache_stat(&fscache_n_allocs_object_dead));
+ if (ret < 0)
+ goto error;
+
+ /* ask the cache to honour the operation */
+ fscache_stat(&fscache_n_cop_allocate_page);
+ ret = object->cache->ops->allocate_page(op, page, gfp);
+ fscache_stat_d(&fscache_n_cop_allocate_page);
+
+error:
+ if (ret == -ERESTARTSYS)
+ fscache_stat(&fscache_n_allocs_intr);
+ else if (ret < 0)
+ fscache_stat(&fscache_n_allocs_nobufs);
+ else
+ fscache_stat(&fscache_n_allocs_ok);
+
+ fscache_put_retrieval(op);
+ _leave(" = %d", ret);
+ return ret;
+
+nobufs_unlock_dec:
+ wake_cookie = __fscache_unuse_cookie(cookie);
+nobufs_unlock:
+ spin_unlock(&cookie->lock);
+ fscache_put_retrieval(op);
+ if (wake_cookie)
+ __fscache_wake_unused_cookie(cookie);
+nobufs:
+ fscache_stat(&fscache_n_allocs_nobufs);
+ _leave(" = -ENOBUFS");
+ return -ENOBUFS;
+}
+EXPORT_SYMBOL(__fscache_alloc_page);
+
+/*
+ * Unmark pages allocate in the readahead code path (via:
+ * fscache_readpages_or_alloc) after delegating to the base filesystem
+ */
+void __fscache_readpages_cancel(struct fscache_cookie *cookie,
+ struct list_head *pages)
+{
+ struct page *page;
+
+ list_for_each_entry(page, pages, lru) {
+ if (PageFsCache(page))
+ __fscache_uncache_page(cookie, page);
+ }
+}
+EXPORT_SYMBOL(__fscache_readpages_cancel);
+
+/*
+ * release a write op reference
+ */
+static void fscache_release_write_op(struct fscache_operation *_op)
+{
+ _enter("{OP%x}", _op->debug_id);
+}
+
+/*
+ * perform the background storage of a page into the cache
+ */
+static void fscache_write_op(struct fscache_operation *_op)
+{
+ struct fscache_storage *op =
+ container_of(_op, struct fscache_storage, op);
+ struct fscache_object *object = op->op.object;
+ struct fscache_cookie *cookie;
+ struct page *page;
+ unsigned n;
+ void *results[1];
+ int ret;
+
+ _enter("{OP%x,%d}", op->op.debug_id, atomic_read(&op->op.usage));
+
+again:
+ spin_lock(&object->lock);
+ cookie = object->cookie;
+
+ if (!fscache_object_is_active(object)) {
+ /* If we get here, then the on-disk cache object likely no
+ * longer exists, so we should just cancel this write
+ * operation.
+ */
+ spin_unlock(&object->lock);
+ fscache_op_complete(&op->op, true);
+ _leave(" [inactive]");
+ return;
+ }
+
+ if (!cookie) {
+ /* If we get here, then the cookie belonging to the object was
+ * detached, probably by the cookie being withdrawn due to
+ * memory pressure, which means that the pages we might write
+ * to the cache from no longer exist - therefore, we can just
+ * cancel this write operation.
+ */
+ spin_unlock(&object->lock);
+ fscache_op_complete(&op->op, true);
+ _leave(" [cancel] op{f=%lx s=%u} obj{s=%s f=%lx}",
+ _op->flags, _op->state, object->state->short_name,
+ object->flags);
+ return;
+ }
+
+ spin_lock(&cookie->stores_lock);
+
+ fscache_stat(&fscache_n_store_calls);
+
+ /* find a page to store */
+ results[0] = NULL;
+ page = NULL;
+ n = radix_tree_gang_lookup_tag(&cookie->stores, results, 0, 1,
+ FSCACHE_COOKIE_PENDING_TAG);
+ trace_fscache_gang_lookup(cookie, &op->op, results, n, op->store_limit);
+ if (n != 1)
+ goto superseded;
+ page = results[0];
+ _debug("gang %d [%lx]", n, page->index);
+
+ radix_tree_tag_set(&cookie->stores, page->index,
+ FSCACHE_COOKIE_STORING_TAG);
+ radix_tree_tag_clear(&cookie->stores, page->index,
+ FSCACHE_COOKIE_PENDING_TAG);
+ trace_fscache_page(cookie, page, fscache_page_radix_pend2store);
+
+ spin_unlock(&cookie->stores_lock);
+ spin_unlock(&object->lock);
+
+ if (page->index >= op->store_limit)
+ goto discard_page;
+
+ fscache_stat(&fscache_n_store_pages);
+ fscache_stat(&fscache_n_cop_write_page);
+ ret = object->cache->ops->write_page(op, page);
+ fscache_stat_d(&fscache_n_cop_write_page);
+ trace_fscache_wrote_page(cookie, page, &op->op, ret);
+ fscache_end_page_write(object, page);
+ if (ret < 0) {
+ fscache_abort_object(object);
+ fscache_op_complete(&op->op, true);
+ } else {
+ fscache_enqueue_operation(&op->op);
+ }
+
+ _leave("");
+ return;
+
+discard_page:
+ fscache_stat(&fscache_n_store_pages_over_limit);
+ trace_fscache_wrote_page(cookie, page, &op->op, -ENOBUFS);
+ fscache_end_page_write(object, page);
+ goto again;
+
+superseded:
+ /* this writer is going away and there aren't any more things to
+ * write */
+ _debug("cease");
+ spin_unlock(&cookie->stores_lock);
+ clear_bit(FSCACHE_OBJECT_PENDING_WRITE, &object->flags);
+ spin_unlock(&object->lock);
+ fscache_op_complete(&op->op, false);
+ _leave("");
+}
+
+/*
+ * Clear the pages pending writing for invalidation
+ */
+void fscache_invalidate_writes(struct fscache_cookie *cookie)
+{
+ struct page *page;
+ void *results[16];
+ int n, i;
+
+ _enter("");
+
+ for (;;) {
+ spin_lock(&cookie->stores_lock);
+ n = radix_tree_gang_lookup_tag(&cookie->stores, results, 0,
+ ARRAY_SIZE(results),
+ FSCACHE_COOKIE_PENDING_TAG);
+ if (n == 0) {
+ spin_unlock(&cookie->stores_lock);
+ break;
+ }
+
+ for (i = n - 1; i >= 0; i--) {
+ page = results[i];
+ radix_tree_delete(&cookie->stores, page->index);
+ trace_fscache_page(cookie, page, fscache_page_radix_delete);
+ trace_fscache_page(cookie, page, fscache_page_inval);
+ }
+
+ spin_unlock(&cookie->stores_lock);
+
+ for (i = n - 1; i >= 0; i--)
+ put_page(results[i]);
+ }
+
+ wake_up_bit(&cookie->flags, 0);
+ trace_fscache_wake_cookie(cookie);
+
+ _leave("");
+}
+
+/*
+ * request a page be stored in the cache
+ * - returns:
+ * -ENOMEM - out of memory, nothing done
+ * -ENOBUFS - no backing object available in which to cache the page
+ * 0 - dispatched a write - it'll call end_io_func() when finished
+ *
+ * if the cookie still has a backing object at this point, that object can be
+ * in one of a few states with respect to storage processing:
+ *
+ * (1) negative lookup, object not yet created (FSCACHE_COOKIE_CREATING is
+ * set)
+ *
+ * (a) no writes yet
+ *
+ * (b) writes deferred till post-creation (mark page for writing and
+ * return immediately)
+ *
+ * (2) negative lookup, object created, initial fill being made from netfs
+ *
+ * (a) fill point not yet reached this page (mark page for writing and
+ * return)
+ *
+ * (b) fill point passed this page (queue op to store this page)
+ *
+ * (3) object extant (queue op to store this page)
+ *
+ * any other state is invalid
+ */
+int __fscache_write_page(struct fscache_cookie *cookie,
+ struct page *page,
+ loff_t object_size,
+ gfp_t gfp)
+{
+ struct fscache_storage *op;
+ struct fscache_object *object;
+ bool wake_cookie = false;
+ int ret;
+
+ _enter("%p,%x,", cookie, (u32) page->flags);
+
+ ASSERTCMP(cookie->def->type, !=, FSCACHE_COOKIE_TYPE_INDEX);
+ ASSERT(PageFsCache(page));
+
+ fscache_stat(&fscache_n_stores);
+
+ if (test_bit(FSCACHE_COOKIE_INVALIDATING, &cookie->flags)) {
+ _leave(" = -ENOBUFS [invalidating]");
+ return -ENOBUFS;
+ }
+
+ op = kzalloc(sizeof(*op), GFP_NOIO | __GFP_NOMEMALLOC | __GFP_NORETRY);
+ if (!op)
+ goto nomem;
+
+ fscache_operation_init(cookie, &op->op, fscache_write_op, NULL,
+ fscache_release_write_op);
+ op->op.flags = FSCACHE_OP_ASYNC |
+ (1 << FSCACHE_OP_WAITING) |
+ (1 << FSCACHE_OP_UNUSE_COOKIE);
+
+ ret = radix_tree_maybe_preload(gfp & ~__GFP_HIGHMEM);
+ if (ret < 0)
+ goto nomem_free;
+
+ trace_fscache_page_op(cookie, page, &op->op, fscache_page_op_write_one);
+
+ ret = -ENOBUFS;
+ spin_lock(&cookie->lock);
+
+ if (!fscache_cookie_enabled(cookie) ||
+ hlist_empty(&cookie->backing_objects))
+ goto nobufs;
+ object = hlist_entry(cookie->backing_objects.first,
+ struct fscache_object, cookie_link);
+ if (test_bit(FSCACHE_IOERROR, &object->cache->flags))
+ goto nobufs;
+
+ trace_fscache_page(cookie, page, fscache_page_write);
+
+ /* add the page to the pending-storage radix tree on the backing
+ * object */
+ spin_lock(&object->lock);
+
+ if (object->store_limit_l != object_size)
+ fscache_set_store_limit(object, object_size);
+
+ spin_lock(&cookie->stores_lock);
+
+ _debug("store limit %llx", (unsigned long long) object->store_limit);
+
+ ret = radix_tree_insert(&cookie->stores, page->index, page);
+ if (ret < 0) {
+ if (ret == -EEXIST)
+ goto already_queued;
+ _debug("insert failed %d", ret);
+ goto nobufs_unlock_obj;
+ }
+
+ trace_fscache_page(cookie, page, fscache_page_radix_insert);
+ radix_tree_tag_set(&cookie->stores, page->index,
+ FSCACHE_COOKIE_PENDING_TAG);
+ trace_fscache_page(cookie, page, fscache_page_radix_set_pend);
+ get_page(page);
+
+ /* we only want one writer at a time, but we do need to queue new
+ * writers after exclusive ops */
+ if (test_and_set_bit(FSCACHE_OBJECT_PENDING_WRITE, &object->flags))
+ goto already_pending;
+
+ spin_unlock(&cookie->stores_lock);
+ spin_unlock(&object->lock);
+
+ op->op.debug_id = atomic_inc_return(&fscache_op_debug_id);
+ op->store_limit = object->store_limit;
+
+ __fscache_use_cookie(cookie);
+ if (fscache_submit_op(object, &op->op) < 0)
+ goto submit_failed;
+
+ spin_unlock(&cookie->lock);
+ radix_tree_preload_end();
+ fscache_stat(&fscache_n_store_ops);
+ fscache_stat(&fscache_n_stores_ok);
+
+ /* the work queue now carries its own ref on the object */
+ fscache_put_operation(&op->op);
+ _leave(" = 0");
+ return 0;
+
+already_queued:
+ fscache_stat(&fscache_n_stores_again);
+already_pending:
+ spin_unlock(&cookie->stores_lock);
+ spin_unlock(&object->lock);
+ spin_unlock(&cookie->lock);
+ radix_tree_preload_end();
+ fscache_put_operation(&op->op);
+ fscache_stat(&fscache_n_stores_ok);
+ _leave(" = 0");
+ return 0;
+
+submit_failed:
+ spin_lock(&cookie->stores_lock);
+ radix_tree_delete(&cookie->stores, page->index);
+ trace_fscache_page(cookie, page, fscache_page_radix_delete);
+ spin_unlock(&cookie->stores_lock);
+ wake_cookie = __fscache_unuse_cookie(cookie);
+ put_page(page);
+ ret = -ENOBUFS;
+ goto nobufs;
+
+nobufs_unlock_obj:
+ spin_unlock(&cookie->stores_lock);
+ spin_unlock(&object->lock);
+nobufs:
+ spin_unlock(&cookie->lock);
+ radix_tree_preload_end();
+ fscache_put_operation(&op->op);
+ if (wake_cookie)
+ __fscache_wake_unused_cookie(cookie);
+ fscache_stat(&fscache_n_stores_nobufs);
+ _leave(" = -ENOBUFS");
+ return -ENOBUFS;
+
+nomem_free:
+ fscache_put_operation(&op->op);
+nomem:
+ fscache_stat(&fscache_n_stores_oom);
+ _leave(" = -ENOMEM");
+ return -ENOMEM;
+}
+EXPORT_SYMBOL(__fscache_write_page);
+
+/*
+ * remove a page from the cache
+ */
+void __fscache_uncache_page(struct fscache_cookie *cookie, struct page *page)
+{
+ struct fscache_object *object;
+
+ _enter(",%p", page);
+
+ ASSERTCMP(cookie->def->type, !=, FSCACHE_COOKIE_TYPE_INDEX);
+ ASSERTCMP(page, !=, NULL);
+
+ fscache_stat(&fscache_n_uncaches);
+
+ /* cache withdrawal may beat us to it */
+ if (!PageFsCache(page))
+ goto done;
+
+ trace_fscache_page(cookie, page, fscache_page_uncache);
+
+ /* get the object */
+ spin_lock(&cookie->lock);
+
+ if (hlist_empty(&cookie->backing_objects)) {
+ ClearPageFsCache(page);
+ goto done_unlock;
+ }
+
+ object = hlist_entry(cookie->backing_objects.first,
+ struct fscache_object, cookie_link);
+
+ /* there might now be stuff on disk we could read */
+ clear_bit(FSCACHE_COOKIE_NO_DATA_YET, &cookie->flags);
+
+ /* only invoke the cache backend if we managed to mark the page
+ * uncached here; this deals with synchronisation vs withdrawal */
+ if (TestClearPageFsCache(page) &&
+ object->cache->ops->uncache_page) {
+ /* the cache backend releases the cookie lock */
+ fscache_stat(&fscache_n_cop_uncache_page);
+ object->cache->ops->uncache_page(object, page);
+ fscache_stat_d(&fscache_n_cop_uncache_page);
+ goto done;
+ }
+
+done_unlock:
+ spin_unlock(&cookie->lock);
+done:
+ _leave("");
+}
+EXPORT_SYMBOL(__fscache_uncache_page);
+
+/**
+ * fscache_mark_page_cached - Mark a page as being cached
+ * @op: The retrieval op pages are being marked for
+ * @page: The page to be marked
+ *
+ * Mark a netfs page as being cached. After this is called, the netfs
+ * must call fscache_uncache_page() to remove the mark.
+ */
+void fscache_mark_page_cached(struct fscache_retrieval *op, struct page *page)
+{
+ struct fscache_cookie *cookie = op->op.object->cookie;
+
+#ifdef CONFIG_FSCACHE_STATS
+ atomic_inc(&fscache_n_marks);
+#endif
+
+ trace_fscache_page(cookie, page, fscache_page_cached);
+
+ _debug("- mark %p{%lx}", page, page->index);
+ if (TestSetPageFsCache(page)) {
+ static bool once_only;
+ if (!once_only) {
+ once_only = true;
+ pr_warn("Cookie type %s marked page %lx multiple times\n",
+ cookie->def->name, page->index);
+ }
+ }
+
+ if (cookie->def->mark_page_cached)
+ cookie->def->mark_page_cached(cookie->netfs_data,
+ op->mapping, page);
+}
+EXPORT_SYMBOL(fscache_mark_page_cached);
+
+/**
+ * fscache_mark_pages_cached - Mark pages as being cached
+ * @op: The retrieval op pages are being marked for
+ * @pagevec: The pages to be marked
+ *
+ * Mark a bunch of netfs pages as being cached. After this is called,
+ * the netfs must call fscache_uncache_page() to remove the mark.
+ */
+void fscache_mark_pages_cached(struct fscache_retrieval *op,
+ struct pagevec *pagevec)
+{
+ unsigned long loop;
+
+ for (loop = 0; loop < pagevec->nr; loop++)
+ fscache_mark_page_cached(op, pagevec->pages[loop]);
+
+ pagevec_reinit(pagevec);
+}
+EXPORT_SYMBOL(fscache_mark_pages_cached);
+
+/*
+ * Uncache all the pages in an inode that are marked PG_fscache, assuming them
+ * to be associated with the given cookie.
+ */
+void __fscache_uncache_all_inode_pages(struct fscache_cookie *cookie,
+ struct inode *inode)
+{
+ struct address_space *mapping = inode->i_mapping;
+ struct pagevec pvec;
+ pgoff_t next;
+ int i;
+
+ _enter("%p,%p", cookie, inode);
+
+ if (!mapping || mapping->nrpages == 0) {
+ _leave(" [no pages]");
+ return;
+ }
+
+ pagevec_init(&pvec);
+ next = 0;
+ do {
+ if (!pagevec_lookup(&pvec, mapping, &next))
+ break;
+ for (i = 0; i < pagevec_count(&pvec); i++) {
+ struct page *page = pvec.pages[i];
+ if (PageFsCache(page)) {
+ __fscache_wait_on_page_write(cookie, page);
+ __fscache_uncache_page(cookie, page);
+ }
+ }
+ pagevec_release(&pvec);
+ cond_resched();
+ } while (next);
+
+ _leave("");
+}
+EXPORT_SYMBOL(__fscache_uncache_all_inode_pages);