Adding upstream version 6.8.9.upstream/6.8.9

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 0 insertions, 1180 deletions

diff --git a/fs/fscache/cookie.c b/fs/fscache/cookie.c
deleted file mode 100644
index bce2492186..0000000000
--- a/fs/fscache/cookie.c
+++ /dev/null
@@ -1,1180 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0-or-later
-/* netfs cookie management
- *
- * Copyright (C) 2021 Red Hat, Inc. All Rights Reserved.
- * Written by David Howells (dhowells@redhat.com)
- *
- * See Documentation/filesystems/caching/netfs-api.rst for more information on
- * the netfs API.
- */
-
-#define FSCACHE_DEBUG_LEVEL COOKIE
-#include <linux/module.h>
-#include <linux/slab.h>
-#include "internal.h"
-
-struct kmem_cache *fscache_cookie_jar;
-
-static void fscache_cookie_lru_timed_out(struct timer_list *timer);
-static void fscache_cookie_lru_worker(struct work_struct *work);
-static void fscache_cookie_worker(struct work_struct *work);
-static void fscache_unhash_cookie(struct fscache_cookie *cookie);
-static void fscache_perform_invalidation(struct fscache_cookie *cookie);
-
-#define fscache_cookie_hash_shift 15
-static struct hlist_bl_head fscache_cookie_hash[1 << fscache_cookie_hash_shift];
-static LIST_HEAD(fscache_cookies);
-static DEFINE_RWLOCK(fscache_cookies_lock);
-static LIST_HEAD(fscache_cookie_lru);
-static DEFINE_SPINLOCK(fscache_cookie_lru_lock);
-DEFINE_TIMER(fscache_cookie_lru_timer, fscache_cookie_lru_timed_out);
-static DECLARE_WORK(fscache_cookie_lru_work, fscache_cookie_lru_worker);
-static const char fscache_cookie_states[FSCACHE_COOKIE_STATE__NR] = "-LCAIFUWRD";
-static unsigned int fscache_lru_cookie_timeout = 10 * HZ;
-
-void fscache_print_cookie(struct fscache_cookie *cookie, char prefix)
-{
-	const u8 *k;
-
-	pr_err("%c-cookie c=%08x [fl=%lx na=%u nA=%u s=%c]\n",
-	       prefix,
-	       cookie->debug_id,
-	       cookie->flags,
-	       atomic_read(&cookie->n_active),
-	       atomic_read(&cookie->n_accesses),
-	       fscache_cookie_states[cookie->state]);
-	pr_err("%c-cookie V=%08x [%s]\n",
-	       prefix,
-	       cookie->volume->debug_id,
-	       cookie->volume->key);
-
-	k = (cookie->key_len <= sizeof(cookie->inline_key)) ?
-		cookie->inline_key : cookie->key;
-	pr_err("%c-key=[%u] '%*phN'\n", prefix, cookie->key_len, cookie->key_len, k);
-}
-
-static void fscache_free_cookie(struct fscache_cookie *cookie)
-{
-	if (WARN_ON_ONCE(!list_empty(&cookie->commit_link))) {
-		spin_lock(&fscache_cookie_lru_lock);
-		list_del_init(&cookie->commit_link);
-		spin_unlock(&fscache_cookie_lru_lock);
-		fscache_stat_d(&fscache_n_cookies_lru);
-		fscache_stat(&fscache_n_cookies_lru_removed);
-	}
-
-	if (WARN_ON_ONCE(test_bit(FSCACHE_COOKIE_IS_HASHED, &cookie->flags))) {
-		fscache_print_cookie(cookie, 'F');
-		return;
-	}
-
-	write_lock(&fscache_cookies_lock);
-	list_del(&cookie->proc_link);
-	write_unlock(&fscache_cookies_lock);
-	if (cookie->aux_len > sizeof(cookie->inline_aux))
-		kfree(cookie->aux);
-	if (cookie->key_len > sizeof(cookie->inline_key))
-		kfree(cookie->key);
-	fscache_stat_d(&fscache_n_cookies);
-	kmem_cache_free(fscache_cookie_jar, cookie);
-}
-
-static void __fscache_queue_cookie(struct fscache_cookie *cookie)
-{
-	if (!queue_work(fscache_wq, &cookie->work))
-		fscache_put_cookie(cookie, fscache_cookie_put_over_queued);
-}
-
-static void fscache_queue_cookie(struct fscache_cookie *cookie,
-				 enum fscache_cookie_trace where)
-{
-	fscache_get_cookie(cookie, where);
-	__fscache_queue_cookie(cookie);
-}
-
-/*
- * Initialise the access gate on a cookie by setting a flag to prevent the
- * state machine from being queued when the access counter transitions to 0.
- * We're only interested in this when we withdraw caching services from the
- * cookie.
- */
-static void fscache_init_access_gate(struct fscache_cookie *cookie)
-{
-	int n_accesses;
-
-	n_accesses = atomic_read(&cookie->n_accesses);
-	trace_fscache_access(cookie->debug_id, refcount_read(&cookie->ref),
-			     n_accesses, fscache_access_cache_pin);
-	set_bit(FSCACHE_COOKIE_NO_ACCESS_WAKE, &cookie->flags);
-}
-
-/**
- * fscache_end_cookie_access - Unpin a cache at the end of an access.
- * @cookie: A data file cookie
- * @why: An indication of the circumstances of the access for tracing
- *
- * Unpin a cache cookie after we've accessed it and bring a deferred
- * relinquishment or withdrawal state into effect.
- *
- * The @why indicator is provided for tracing purposes.
- */
-void fscache_end_cookie_access(struct fscache_cookie *cookie,
-			       enum fscache_access_trace why)
-{
-	int n_accesses;
-
-	smp_mb__before_atomic();
-	n_accesses = atomic_dec_return(&cookie->n_accesses);
-	trace_fscache_access(cookie->debug_id, refcount_read(&cookie->ref),
-			     n_accesses, why);
-	if (n_accesses == 0 &&
-	    !test_bit(FSCACHE_COOKIE_NO_ACCESS_WAKE, &cookie->flags))
-		fscache_queue_cookie(cookie, fscache_cookie_get_end_access);
-}
-EXPORT_SYMBOL(fscache_end_cookie_access);
-
-/*
- * Pin the cache behind a cookie so that we can access it.
- */
-static void __fscache_begin_cookie_access(struct fscache_cookie *cookie,
-					  enum fscache_access_trace why)
-{
-	int n_accesses;
-
-	n_accesses = atomic_inc_return(&cookie->n_accesses);
-	smp_mb__after_atomic(); /* (Future) read state after is-caching.
-				 * Reread n_accesses after is-caching
-				 */
-	trace_fscache_access(cookie->debug_id, refcount_read(&cookie->ref),
-			     n_accesses, why);
-}
-
-/**
- * fscache_begin_cookie_access - Pin a cache so data can be accessed
- * @cookie: A data file cookie
- * @why: An indication of the circumstances of the access for tracing
- *
- * Attempt to pin the cache to prevent it from going away whilst we're
- * accessing data and returns true if successful.  This works as follows:
- *
- *  (1) If the cookie is not being cached (ie. FSCACHE_COOKIE_IS_CACHING is not
- *      set), we return false to indicate access was not permitted.
- *
- *  (2) If the cookie is being cached, we increment its n_accesses count and
- *      then recheck the IS_CACHING flag, ending the access if it got cleared.
- *
- *  (3) When we end the access, we decrement the cookie's n_accesses and wake
- *      up the any waiters if it reaches 0.
- *
- *  (4) Whilst the cookie is actively being cached, its n_accesses is kept
- *      artificially incremented to prevent wakeups from happening.
- *
- *  (5) When the cache is taken offline or if the cookie is culled, the flag is
- *      cleared to prevent new accesses, the cookie's n_accesses is decremented
- *      and we wait for it to become 0.
- *
- * The @why indicator are merely provided for tracing purposes.
- */
-bool fscache_begin_cookie_access(struct fscache_cookie *cookie,
-				 enum fscache_access_trace why)
-{
-	if (!test_bit(FSCACHE_COOKIE_IS_CACHING, &cookie->flags))
-		return false;
-	__fscache_begin_cookie_access(cookie, why);
-	if (!test_bit(FSCACHE_COOKIE_IS_CACHING, &cookie->flags) ||
-	    !fscache_cache_is_live(cookie->volume->cache)) {
-		fscache_end_cookie_access(cookie, fscache_access_unlive);
-		return false;
-	}
-	return true;
-}
-
-static inline void wake_up_cookie_state(struct fscache_cookie *cookie)
-{
-	/* Use a barrier to ensure that waiters see the state variable
-	 * change, as spin_unlock doesn't guarantee a barrier.
-	 *
-	 * See comments over wake_up_bit() and waitqueue_active().
-	 */
-	smp_mb();
-	wake_up_var(&cookie->state);
-}
-
-/*
- * Change the state a cookie is at and wake up anyone waiting for that.  Impose
- * an ordering between the stuff stored in the cookie and the state member.
- * Paired with fscache_cookie_state().
- */
-static void __fscache_set_cookie_state(struct fscache_cookie *cookie,
-				       enum fscache_cookie_state state)
-{
-	smp_store_release(&cookie->state, state);
-}
-
-static void fscache_set_cookie_state(struct fscache_cookie *cookie,
-				     enum fscache_cookie_state state)
-{
-	spin_lock(&cookie->lock);
-	__fscache_set_cookie_state(cookie, state);
-	spin_unlock(&cookie->lock);
-	wake_up_cookie_state(cookie);
-}
-
-/**
- * fscache_cookie_lookup_negative - Note negative lookup
- * @cookie: The cookie that was being looked up
- *
- * Note that some part of the metadata path in the cache doesn't exist and so
- * we can release any waiting readers in the certain knowledge that there's
- * nothing for them to actually read.
- *
- * This function uses no locking and must only be called from the state machine.
- */
-void fscache_cookie_lookup_negative(struct fscache_cookie *cookie)
-{
-	set_bit(FSCACHE_COOKIE_NO_DATA_TO_READ, &cookie->flags);
-	fscache_set_cookie_state(cookie, FSCACHE_COOKIE_STATE_CREATING);
-}
-EXPORT_SYMBOL(fscache_cookie_lookup_negative);
-
-/**
- * fscache_resume_after_invalidation - Allow I/O to resume after invalidation
- * @cookie: The cookie that was invalidated
- *
- * Tell fscache that invalidation is sufficiently complete that I/O can be
- * allowed again.
- */
-void fscache_resume_after_invalidation(struct fscache_cookie *cookie)
-{
-	fscache_set_cookie_state(cookie, FSCACHE_COOKIE_STATE_ACTIVE);
-}
-EXPORT_SYMBOL(fscache_resume_after_invalidation);
-
-/**
- * fscache_caching_failed - Report that a failure stopped caching on a cookie
- * @cookie: The cookie that was affected
- *
- * Tell fscache that caching on a cookie needs to be stopped due to some sort
- * of failure.
- *
- * This function uses no locking and must only be called from the state machine.
- */
-void fscache_caching_failed(struct fscache_cookie *cookie)
-{
-	clear_bit(FSCACHE_COOKIE_IS_CACHING, &cookie->flags);
-	fscache_set_cookie_state(cookie, FSCACHE_COOKIE_STATE_FAILED);
-	trace_fscache_cookie(cookie->debug_id, refcount_read(&cookie->ref),
-				fscache_cookie_failed);
-}
-EXPORT_SYMBOL(fscache_caching_failed);
-
-/*
- * Set the index key in a cookie.  The cookie struct has space for a 16-byte
- * key plus length and hash, but if that's not big enough, it's instead a
- * pointer to a buffer containing 3 bytes of hash, 1 byte of length and then
- * the key data.
- */
-static int fscache_set_key(struct fscache_cookie *cookie,
-			   const void *index_key, size_t index_key_len)
-{
-	void *buf;
-	size_t buf_size;
-
-	buf_size = round_up(index_key_len, sizeof(__le32));
-
-	if (index_key_len > sizeof(cookie->inline_key)) {
-		buf = kzalloc(buf_size, GFP_KERNEL);
-		if (!buf)
-			return -ENOMEM;
-		cookie->key = buf;
-	} else {
-		buf = cookie->inline_key;
-	}
-
-	memcpy(buf, index_key, index_key_len);
-	cookie->key_hash = fscache_hash(cookie->volume->key_hash,
-					buf, buf_size);
-	return 0;
-}
-
-static bool fscache_cookie_same(const struct fscache_cookie *a,
-				const struct fscache_cookie *b)
-{
-	const void *ka, *kb;
-
-	if (a->key_hash	!= b->key_hash ||
-	    a->volume	!= b->volume ||
-	    a->key_len	!= b->key_len)
-		return false;
-
-	if (a->key_len <= sizeof(a->inline_key)) {
-		ka = &a->inline_key;
-		kb = &b->inline_key;
-	} else {
-		ka = a->key;
-		kb = b->key;
-	}
-	return memcmp(ka, kb, a->key_len) == 0;
-}
-
-static atomic_t fscache_cookie_debug_id = ATOMIC_INIT(1);
-
-/*
- * Allocate a cookie.
- */
-static struct fscache_cookie *fscache_alloc_cookie(
-	struct fscache_volume *volume,
-	u8 advice,
-	const void *index_key, size_t index_key_len,
-	const void *aux_data, size_t aux_data_len,
-	loff_t object_size)
-{
-	struct fscache_cookie *cookie;
-
-	/* allocate and initialise a cookie */
-	cookie = kmem_cache_zalloc(fscache_cookie_jar, GFP_KERNEL);
-	if (!cookie)
-		return NULL;
-	fscache_stat(&fscache_n_cookies);
-
-	cookie->volume		= volume;
-	cookie->advice		= advice;
-	cookie->key_len		= index_key_len;
-	cookie->aux_len		= aux_data_len;
-	cookie->object_size	= object_size;
-	if (object_size == 0)
-		__set_bit(FSCACHE_COOKIE_NO_DATA_TO_READ, &cookie->flags);
-
-	if (fscache_set_key(cookie, index_key, index_key_len) < 0)
-		goto nomem;
-
-	if (cookie->aux_len <= sizeof(cookie->inline_aux)) {
-		memcpy(cookie->inline_aux, aux_data, cookie->aux_len);
-	} else {
-		cookie->aux = kmemdup(aux_data, cookie->aux_len, GFP_KERNEL);
-		if (!cookie->aux)
-			goto nomem;
-	}
-
-	refcount_set(&cookie->ref, 1);
-	cookie->debug_id = atomic_inc_return(&fscache_cookie_debug_id);
-	spin_lock_init(&cookie->lock);
-	INIT_LIST_HEAD(&cookie->commit_link);
-	INIT_WORK(&cookie->work, fscache_cookie_worker);
-	__fscache_set_cookie_state(cookie, FSCACHE_COOKIE_STATE_QUIESCENT);
-
-	write_lock(&fscache_cookies_lock);
-	list_add_tail(&cookie->proc_link, &fscache_cookies);
-	write_unlock(&fscache_cookies_lock);
-	fscache_see_cookie(cookie, fscache_cookie_new_acquire);
-	return cookie;
-
-nomem:
-	fscache_free_cookie(cookie);
-	return NULL;
-}
-
-static inline bool fscache_cookie_is_dropped(struct fscache_cookie *cookie)
-{
-	return READ_ONCE(cookie->state) == FSCACHE_COOKIE_STATE_DROPPED;
-}
-
-static void fscache_wait_on_collision(struct fscache_cookie *candidate,
-				      struct fscache_cookie *wait_for)
-{
-	enum fscache_cookie_state *statep = &wait_for->state;
-
-	wait_var_event_timeout(statep, fscache_cookie_is_dropped(wait_for),
-			       20 * HZ);
-	if (!fscache_cookie_is_dropped(wait_for)) {
-		pr_notice("Potential collision c=%08x old: c=%08x",
-			  candidate->debug_id, wait_for->debug_id);
-		wait_var_event(statep, fscache_cookie_is_dropped(wait_for));
-	}
-}
-
-/*
- * Attempt to insert the new cookie into the hash.  If there's a collision, we
- * wait for the old cookie to complete if it's being relinquished and an error
- * otherwise.
- */
-static bool fscache_hash_cookie(struct fscache_cookie *candidate)
-{
-	struct fscache_cookie *cursor, *wait_for = NULL;
-	struct hlist_bl_head *h;
-	struct hlist_bl_node *p;
-	unsigned int bucket;
-
-	bucket = candidate->key_hash & (ARRAY_SIZE(fscache_cookie_hash) - 1);
-	h = &fscache_cookie_hash[bucket];
-
-	hlist_bl_lock(h);
-	hlist_bl_for_each_entry(cursor, p, h, hash_link) {
-		if (fscache_cookie_same(candidate, cursor)) {
-			if (!test_bit(FSCACHE_COOKIE_RELINQUISHED, &cursor->flags))
-				goto collision;
-			wait_for = fscache_get_cookie(cursor,
-						      fscache_cookie_get_hash_collision);
-			break;
-		}
-	}
-
-	fscache_get_volume(candidate->volume, fscache_volume_get_cookie);
-	atomic_inc(&candidate->volume->n_cookies);
-	hlist_bl_add_head(&candidate->hash_link, h);
-	set_bit(FSCACHE_COOKIE_IS_HASHED, &candidate->flags);
-	hlist_bl_unlock(h);
-
-	if (wait_for) {
-		fscache_wait_on_collision(candidate, wait_for);
-		fscache_put_cookie(wait_for, fscache_cookie_put_hash_collision);
-	}
-	return true;
-
-collision:
-	trace_fscache_cookie(cursor->debug_id, refcount_read(&cursor->ref),
-			     fscache_cookie_collision);
-	pr_err("Duplicate cookie detected\n");
-	fscache_print_cookie(cursor, 'O');
-	fscache_print_cookie(candidate, 'N');
-	hlist_bl_unlock(h);
-	return false;
-}
-
-/*
- * Request a cookie to represent a data storage object within a volume.
- *
- * We never let on to the netfs about errors.  We may set a negative cookie
- * pointer, but that's okay
- */
-struct fscache_cookie *__fscache_acquire_cookie(
-	struct fscache_volume *volume,
-	u8 advice,
-	const void *index_key, size_t index_key_len,
-	const void *aux_data, size_t aux_data_len,
-	loff_t object_size)
-{
-	struct fscache_cookie *cookie;
-
-	_enter("V=%x", volume->debug_id);
-
-	if (!index_key || !index_key_len || index_key_len > 255 || aux_data_len > 255)
-		return NULL;
-	if (!aux_data || !aux_data_len) {
-		aux_data = NULL;
-		aux_data_len = 0;
-	}
-
-	fscache_stat(&fscache_n_acquires);
-
-	cookie = fscache_alloc_cookie(volume, advice,
-				      index_key, index_key_len,
-				      aux_data, aux_data_len,
-				      object_size);
-	if (!cookie) {
-		fscache_stat(&fscache_n_acquires_oom);
-		return NULL;
-	}
-
-	if (!fscache_hash_cookie(cookie)) {
-		fscache_see_cookie(cookie, fscache_cookie_discard);
-		fscache_free_cookie(cookie);
-		return NULL;
-	}
-
-	trace_fscache_acquire(cookie);
-	fscache_stat(&fscache_n_acquires_ok);
-	_leave(" = c=%08x", cookie->debug_id);
-	return cookie;
-}
-EXPORT_SYMBOL(__fscache_acquire_cookie);
-
-/*
- * Prepare a cache object to be written to.
- */
-static void fscache_prepare_to_write(struct fscache_cookie *cookie)
-{
-	cookie->volume->cache->ops->prepare_to_write(cookie);
-}
-
-/*
- * Look up a cookie in the cache.
- */
-static void fscache_perform_lookup(struct fscache_cookie *cookie)
-{
-	enum fscache_access_trace trace = fscache_access_lookup_cookie_end_failed;
-	bool need_withdraw = false;
-
-	_enter("");
-
-	if (!cookie->volume->cache_priv) {
-		fscache_create_volume(cookie->volume, true);
-		if (!cookie->volume->cache_priv) {
-			fscache_set_cookie_state(cookie, FSCACHE_COOKIE_STATE_QUIESCENT);
-			goto out;
-		}
-	}
-
-	if (!cookie->volume->cache->ops->lookup_cookie(cookie)) {
-		if (cookie->state != FSCACHE_COOKIE_STATE_FAILED)
-			fscache_set_cookie_state(cookie, FSCACHE_COOKIE_STATE_QUIESCENT);
-		need_withdraw = true;
-		_leave(" [fail]");
-		goto out;
-	}
-
-	fscache_see_cookie(cookie, fscache_cookie_see_active);
-	spin_lock(&cookie->lock);
-	if (test_and_clear_bit(FSCACHE_COOKIE_DO_INVALIDATE, &cookie->flags))
-		__fscache_set_cookie_state(cookie,
-					   FSCACHE_COOKIE_STATE_INVALIDATING);
-	else
-		__fscache_set_cookie_state(cookie, FSCACHE_COOKIE_STATE_ACTIVE);
-	spin_unlock(&cookie->lock);
-	wake_up_cookie_state(cookie);
-	trace = fscache_access_lookup_cookie_end;
-
-out:
-	fscache_end_cookie_access(cookie, trace);
-	if (need_withdraw)
-		fscache_withdraw_cookie(cookie);
-	fscache_end_volume_access(cookie->volume, cookie, trace);
-}
-
-/*
- * Begin the process of looking up a cookie.  We offload the actual process to
- * a worker thread.
- */
-static bool fscache_begin_lookup(struct fscache_cookie *cookie, bool will_modify)
-{
-	if (will_modify) {
-		set_bit(FSCACHE_COOKIE_LOCAL_WRITE, &cookie->flags);
-		set_bit(FSCACHE_COOKIE_DO_PREP_TO_WRITE, &cookie->flags);
-	}
-	if (!fscache_begin_volume_access(cookie->volume, cookie,
-					 fscache_access_lookup_cookie))
-		return false;
-
-	__fscache_begin_cookie_access(cookie, fscache_access_lookup_cookie);
-	__fscache_set_cookie_state(cookie, FSCACHE_COOKIE_STATE_LOOKING_UP);
-	set_bit(FSCACHE_COOKIE_IS_CACHING, &cookie->flags);
-	set_bit(FSCACHE_COOKIE_HAS_BEEN_CACHED, &cookie->flags);
-	return true;
-}
-
-/*
- * Start using the cookie for I/O.  This prevents the backing object from being
- * reaped by VM pressure.
- */
-void __fscache_use_cookie(struct fscache_cookie *cookie, bool will_modify)
-{
-	enum fscache_cookie_state state;
-	bool queue = false;
-	int n_active;
-
-	_enter("c=%08x", cookie->debug_id);
-
-	if (WARN(test_bit(FSCACHE_COOKIE_RELINQUISHED, &cookie->flags),
-		 "Trying to use relinquished cookie\n"))
-		return;
-
-	spin_lock(&cookie->lock);
-
-	n_active = atomic_inc_return(&cookie->n_active);
-	trace_fscache_active(cookie->debug_id, refcount_read(&cookie->ref),
-			     n_active, atomic_read(&cookie->n_accesses),
-			     will_modify ?
-			     fscache_active_use_modify : fscache_active_use);
-
-again:
-	state = fscache_cookie_state(cookie);
-	switch (state) {
-	case FSCACHE_COOKIE_STATE_QUIESCENT:
-		queue = fscache_begin_lookup(cookie, will_modify);
-		break;
-
-	case FSCACHE_COOKIE_STATE_LOOKING_UP:
-	case FSCACHE_COOKIE_STATE_CREATING:
-		if (will_modify)
-			set_bit(FSCACHE_COOKIE_LOCAL_WRITE, &cookie->flags);
-		break;
-	case FSCACHE_COOKIE_STATE_ACTIVE:
-	case FSCACHE_COOKIE_STATE_INVALIDATING:
-		if (will_modify &&
-		    !test_and_set_bit(FSCACHE_COOKIE_LOCAL_WRITE, &cookie->flags)) {
-			set_bit(FSCACHE_COOKIE_DO_PREP_TO_WRITE, &cookie->flags);
-			queue = true;
-		}
-		/*
-		 * We could race with cookie_lru which may set LRU_DISCARD bit
-		 * but has yet to run the cookie state machine.  If this happens
-		 * and another thread tries to use the cookie, clear LRU_DISCARD
-		 * so we don't end up withdrawing the cookie while in use.
-		 */
-		if (test_and_clear_bit(FSCACHE_COOKIE_DO_LRU_DISCARD, &cookie->flags))
-			fscache_see_cookie(cookie, fscache_cookie_see_lru_discard_clear);
-		break;
-
-	case FSCACHE_COOKIE_STATE_FAILED:
-	case FSCACHE_COOKIE_STATE_WITHDRAWING:
-		break;
-
-	case FSCACHE_COOKIE_STATE_LRU_DISCARDING:
-		spin_unlock(&cookie->lock);
-		wait_var_event(&cookie->state,
-			       fscache_cookie_state(cookie) !=
-			       FSCACHE_COOKIE_STATE_LRU_DISCARDING);
-		spin_lock(&cookie->lock);
-		goto again;
-
-	case FSCACHE_COOKIE_STATE_DROPPED:
-	case FSCACHE_COOKIE_STATE_RELINQUISHING:
-		WARN(1, "Can't use cookie in state %u\n", state);
-		break;
-	}
-
-	spin_unlock(&cookie->lock);
-	if (queue)
-		fscache_queue_cookie(cookie, fscache_cookie_get_use_work);
-	_leave("");
-}
-EXPORT_SYMBOL(__fscache_use_cookie);
-
-static void fscache_unuse_cookie_locked(struct fscache_cookie *cookie)
-{
-	clear_bit(FSCACHE_COOKIE_DISABLED, &cookie->flags);
-	if (!test_bit(FSCACHE_COOKIE_IS_CACHING, &cookie->flags))
-		return;
-
-	cookie->unused_at = jiffies;
-	spin_lock(&fscache_cookie_lru_lock);
-	if (list_empty(&cookie->commit_link)) {
-		fscache_get_cookie(cookie, fscache_cookie_get_lru);
-		fscache_stat(&fscache_n_cookies_lru);
-	}
-	list_move_tail(&cookie->commit_link, &fscache_cookie_lru);
-
-	spin_unlock(&fscache_cookie_lru_lock);
-	timer_reduce(&fscache_cookie_lru_timer,
-		     jiffies + fscache_lru_cookie_timeout);
-}
-
-/*
- * Stop using the cookie for I/O.
- */
-void __fscache_unuse_cookie(struct fscache_cookie *cookie,
-			    const void *aux_data, const loff_t *object_size)
-{
-	unsigned int debug_id = cookie->debug_id;
-	unsigned int r = refcount_read(&cookie->ref);
-	unsigned int a = atomic_read(&cookie->n_accesses);
-	unsigned int c;
-
-	if (aux_data || object_size)
-		__fscache_update_cookie(cookie, aux_data, object_size);
-
-	/* Subtract 1 from counter unless that drops it to 0 (ie. it was 1) */
-	c = atomic_fetch_add_unless(&cookie->n_active, -1, 1);
-	if (c != 1) {
-		trace_fscache_active(debug_id, r, c - 1, a, fscache_active_unuse);
-		return;
-	}
-
-	spin_lock(&cookie->lock);
-	r = refcount_read(&cookie->ref);
-	a = atomic_read(&cookie->n_accesses);
-	c = atomic_dec_return(&cookie->n_active);
-	trace_fscache_active(debug_id, r, c, a, fscache_active_unuse);
-	if (c == 0)
-		fscache_unuse_cookie_locked(cookie);
-	spin_unlock(&cookie->lock);
-}
-EXPORT_SYMBOL(__fscache_unuse_cookie);
-
-/*
- * Perform work upon the cookie, such as committing its cache state,
- * relinquishing it or withdrawing the backing cache.  We're protected from the
- * cache going away under us as object withdrawal must come through this
- * non-reentrant work item.
- */
-static void fscache_cookie_state_machine(struct fscache_cookie *cookie)
-{
-	enum fscache_cookie_state state;
-	bool wake = false;
-
-	_enter("c=%x", cookie->debug_id);
-
-again:
-	spin_lock(&cookie->lock);
-again_locked:
-	state = cookie->state;
-	switch (state) {
-	case FSCACHE_COOKIE_STATE_QUIESCENT:
-		/* The QUIESCENT state is jumped to the LOOKING_UP state by
-		 * fscache_use_cookie().
-		 */
-
-		if (atomic_read(&cookie->n_accesses) == 0 &&
-		    test_bit(FSCACHE_COOKIE_DO_RELINQUISH, &cookie->flags)) {
-			__fscache_set_cookie_state(cookie,
-						   FSCACHE_COOKIE_STATE_RELINQUISHING);
-			wake = true;
-			goto again_locked;
-		}
-		break;
-
-	case FSCACHE_COOKIE_STATE_LOOKING_UP:
-		spin_unlock(&cookie->lock);
-		fscache_init_access_gate(cookie);
-		fscache_perform_lookup(cookie);
-		goto again;
-
-	case FSCACHE_COOKIE_STATE_INVALIDATING:
-		spin_unlock(&cookie->lock);
-		fscache_perform_invalidation(cookie);
-		goto again;
-
-	case FSCACHE_COOKIE_STATE_ACTIVE:
-		if (test_and_clear_bit(FSCACHE_COOKIE_DO_PREP_TO_WRITE, &cookie->flags)) {
-			spin_unlock(&cookie->lock);
-			fscache_prepare_to_write(cookie);
-			spin_lock(&cookie->lock);
-		}
-		if (test_bit(FSCACHE_COOKIE_DO_LRU_DISCARD, &cookie->flags)) {
-			__fscache_set_cookie_state(cookie,
-						   FSCACHE_COOKIE_STATE_LRU_DISCARDING);
-			wake = true;
-			goto again_locked;
-		}
-		fallthrough;
-
-	case FSCACHE_COOKIE_STATE_FAILED:
-		if (test_and_clear_bit(FSCACHE_COOKIE_DO_INVALIDATE, &cookie->flags))
-			fscache_end_cookie_access(cookie, fscache_access_invalidate_cookie_end);
-
-		if (atomic_read(&cookie->n_accesses) != 0)
-			break;
-		if (test_bit(FSCACHE_COOKIE_DO_RELINQUISH, &cookie->flags)) {
-			__fscache_set_cookie_state(cookie,
-						   FSCACHE_COOKIE_STATE_RELINQUISHING);
-			wake = true;
-			goto again_locked;
-		}
-		if (test_bit(FSCACHE_COOKIE_DO_WITHDRAW, &cookie->flags)) {
-			__fscache_set_cookie_state(cookie,
-						   FSCACHE_COOKIE_STATE_WITHDRAWING);
-			wake = true;
-			goto again_locked;
-		}
-		break;
-
-	case FSCACHE_COOKIE_STATE_LRU_DISCARDING:
-	case FSCACHE_COOKIE_STATE_RELINQUISHING:
-	case FSCACHE_COOKIE_STATE_WITHDRAWING:
-		if (cookie->cache_priv) {
-			spin_unlock(&cookie->lock);
-			cookie->volume->cache->ops->withdraw_cookie(cookie);
-			spin_lock(&cookie->lock);
-		}
-
-		if (test_and_clear_bit(FSCACHE_COOKIE_DO_INVALIDATE, &cookie->flags))
-			fscache_end_cookie_access(cookie, fscache_access_invalidate_cookie_end);
-
-		switch (state) {
-		case FSCACHE_COOKIE_STATE_RELINQUISHING:
-			fscache_see_cookie(cookie, fscache_cookie_see_relinquish);
-			fscache_unhash_cookie(cookie);
-			__fscache_set_cookie_state(cookie,
-						   FSCACHE_COOKIE_STATE_DROPPED);
-			wake = true;
-			goto out;
-		case FSCACHE_COOKIE_STATE_LRU_DISCARDING:
-			fscache_see_cookie(cookie, fscache_cookie_see_lru_discard);
-			break;
-		case FSCACHE_COOKIE_STATE_WITHDRAWING:
-			fscache_see_cookie(cookie, fscache_cookie_see_withdraw);
-			break;
-		default:
-			BUG();
-		}
-
-		clear_bit(FSCACHE_COOKIE_NEEDS_UPDATE, &cookie->flags);
-		clear_bit(FSCACHE_COOKIE_DO_WITHDRAW, &cookie->flags);
-		clear_bit(FSCACHE_COOKIE_DO_LRU_DISCARD, &cookie->flags);
-		clear_bit(FSCACHE_COOKIE_DO_PREP_TO_WRITE, &cookie->flags);
-		set_bit(FSCACHE_COOKIE_NO_DATA_TO_READ, &cookie->flags);
-		__fscache_set_cookie_state(cookie, FSCACHE_COOKIE_STATE_QUIESCENT);
-		wake = true;
-		goto again_locked;
-
-	case FSCACHE_COOKIE_STATE_DROPPED:
-		break;
-
-	default:
-		WARN_ONCE(1, "Cookie %x in unexpected state %u\n",
-			  cookie->debug_id, state);
-		break;
-	}
-
-out:
-	spin_unlock(&cookie->lock);
-	if (wake)
-		wake_up_cookie_state(cookie);
-	_leave("");
-}
-
-static void fscache_cookie_worker(struct work_struct *work)
-{
-	struct fscache_cookie *cookie = container_of(work, struct fscache_cookie, work);
-
-	fscache_see_cookie(cookie, fscache_cookie_see_work);
-	fscache_cookie_state_machine(cookie);
-	fscache_put_cookie(cookie, fscache_cookie_put_work);
-}
-
-/*
- * Wait for the object to become inactive.  The cookie's work item will be
- * scheduled when someone transitions n_accesses to 0 - but if someone's
- * already done that, schedule it anyway.
- */
-static void __fscache_withdraw_cookie(struct fscache_cookie *cookie)
-{
-	int n_accesses;
-	bool unpinned;
-
-	unpinned = test_and_clear_bit(FSCACHE_COOKIE_NO_ACCESS_WAKE, &cookie->flags);
-
-	/* Need to read the access count after unpinning */
-	n_accesses = atomic_read(&cookie->n_accesses);
-	if (unpinned)
-		trace_fscache_access(cookie->debug_id, refcount_read(&cookie->ref),
-				     n_accesses, fscache_access_cache_unpin);
-	if (n_accesses == 0)
-		fscache_queue_cookie(cookie, fscache_cookie_get_end_access);
-}
-
-static void fscache_cookie_lru_do_one(struct fscache_cookie *cookie)
-{
-	fscache_see_cookie(cookie, fscache_cookie_see_lru_do_one);
-
-	spin_lock(&cookie->lock);
-	if (cookie->state != FSCACHE_COOKIE_STATE_ACTIVE ||
-	    time_before(jiffies, cookie->unused_at + fscache_lru_cookie_timeout) ||
-	    atomic_read(&cookie->n_active) > 0) {
-		spin_unlock(&cookie->lock);
-		fscache_stat(&fscache_n_cookies_lru_removed);
-	} else {
-		set_bit(FSCACHE_COOKIE_DO_LRU_DISCARD, &cookie->flags);
-		spin_unlock(&cookie->lock);
-		fscache_stat(&fscache_n_cookies_lru_expired);
-		_debug("lru c=%x", cookie->debug_id);
-		__fscache_withdraw_cookie(cookie);
-	}
-
-	fscache_put_cookie(cookie, fscache_cookie_put_lru);
-}
-
-static void fscache_cookie_lru_worker(struct work_struct *work)
-{
-	struct fscache_cookie *cookie;
-	unsigned long unused_at;
-
-	spin_lock(&fscache_cookie_lru_lock);
-
-	while (!list_empty(&fscache_cookie_lru)) {
-		cookie = list_first_entry(&fscache_cookie_lru,
-					  struct fscache_cookie, commit_link);
-		unused_at = cookie->unused_at + fscache_lru_cookie_timeout;
-		if (time_before(jiffies, unused_at)) {
-			timer_reduce(&fscache_cookie_lru_timer, unused_at);
-			break;
-		}
-
-		list_del_init(&cookie->commit_link);
-		fscache_stat_d(&fscache_n_cookies_lru);
-		spin_unlock(&fscache_cookie_lru_lock);
-		fscache_cookie_lru_do_one(cookie);
-		spin_lock(&fscache_cookie_lru_lock);
-	}
-
-	spin_unlock(&fscache_cookie_lru_lock);
-}
-
-static void fscache_cookie_lru_timed_out(struct timer_list *timer)
-{
-	queue_work(fscache_wq, &fscache_cookie_lru_work);
-}
-
-static void fscache_cookie_drop_from_lru(struct fscache_cookie *cookie)
-{
-	bool need_put = false;
-
-	if (!list_empty(&cookie->commit_link)) {
-		spin_lock(&fscache_cookie_lru_lock);
-		if (!list_empty(&cookie->commit_link)) {
-			list_del_init(&cookie->commit_link);
-			fscache_stat_d(&fscache_n_cookies_lru);
-			fscache_stat(&fscache_n_cookies_lru_dropped);
-			need_put = true;
-		}
-		spin_unlock(&fscache_cookie_lru_lock);
-		if (need_put)
-			fscache_put_cookie(cookie, fscache_cookie_put_lru);
-	}
-}
-
-/*
- * Remove a cookie from the hash table.
- */
-static void fscache_unhash_cookie(struct fscache_cookie *cookie)
-{
-	struct hlist_bl_head *h;
-	unsigned int bucket;
-
-	bucket = cookie->key_hash & (ARRAY_SIZE(fscache_cookie_hash) - 1);
-	h = &fscache_cookie_hash[bucket];
-
-	hlist_bl_lock(h);
-	hlist_bl_del(&cookie->hash_link);
-	clear_bit(FSCACHE_COOKIE_IS_HASHED, &cookie->flags);
-	hlist_bl_unlock(h);
-	fscache_stat(&fscache_n_relinquishes_dropped);
-}
-
-static void fscache_drop_withdraw_cookie(struct fscache_cookie *cookie)
-{
-	fscache_cookie_drop_from_lru(cookie);
-	__fscache_withdraw_cookie(cookie);
-}
-
-/**
- * fscache_withdraw_cookie - Mark a cookie for withdrawal
- * @cookie: The cookie to be withdrawn.
- *
- * Allow the cache backend to withdraw the backing for a cookie for its own
- * reasons, even if that cookie is in active use.
- */
-void fscache_withdraw_cookie(struct fscache_cookie *cookie)
-{
-	set_bit(FSCACHE_COOKIE_DO_WITHDRAW, &cookie->flags);
-	fscache_drop_withdraw_cookie(cookie);
-}
-EXPORT_SYMBOL(fscache_withdraw_cookie);
-
-/*
- * Allow the netfs to release a cookie back to the cache.
- * - the object will be marked as recyclable on disk if retire is true
- */
-void __fscache_relinquish_cookie(struct fscache_cookie *cookie, bool retire)
-{
-	fscache_stat(&fscache_n_relinquishes);
-	if (retire)
-		fscache_stat(&fscache_n_relinquishes_retire);
-
-	_enter("c=%08x{%d},%d",
-	       cookie->debug_id, atomic_read(&cookie->n_active), retire);
-
-	if (WARN(test_and_set_bit(FSCACHE_COOKIE_RELINQUISHED, &cookie->flags),
-		 "Cookie c=%x already relinquished\n", cookie->debug_id))
-		return;
-
-	if (retire)
-		set_bit(FSCACHE_COOKIE_RETIRED, &cookie->flags);
-	trace_fscache_relinquish(cookie, retire);
-
-	ASSERTCMP(atomic_read(&cookie->n_active), ==, 0);
-	ASSERTCMP(atomic_read(&cookie->volume->n_cookies), >, 0);
-	atomic_dec(&cookie->volume->n_cookies);
-
-	if (test_bit(FSCACHE_COOKIE_HAS_BEEN_CACHED, &cookie->flags)) {
-		set_bit(FSCACHE_COOKIE_DO_RELINQUISH, &cookie->flags);
-		fscache_drop_withdraw_cookie(cookie);
-	} else {
-		fscache_set_cookie_state(cookie, FSCACHE_COOKIE_STATE_DROPPED);
-		fscache_unhash_cookie(cookie);
-	}
-	fscache_put_cookie(cookie, fscache_cookie_put_relinquish);
-}
-EXPORT_SYMBOL(__fscache_relinquish_cookie);
-
-/*
- * Drop a reference to a cookie.
- */
-void fscache_put_cookie(struct fscache_cookie *cookie,
-			enum fscache_cookie_trace where)
-{
-	struct fscache_volume *volume = cookie->volume;
-	unsigned int cookie_debug_id = cookie->debug_id;
-	bool zero;
-	int ref;
-
-	zero = __refcount_dec_and_test(&cookie->ref, &ref);
-	trace_fscache_cookie(cookie_debug_id, ref - 1, where);
-	if (zero) {
-		fscache_free_cookie(cookie);
-		fscache_put_volume(volume, fscache_volume_put_cookie);
-	}
-}
-EXPORT_SYMBOL(fscache_put_cookie);
-
-/*
- * Get a reference to a cookie.
- */
-struct fscache_cookie *fscache_get_cookie(struct fscache_cookie *cookie,
-					  enum fscache_cookie_trace where)
-{
-	int ref;
-
-	__refcount_inc(&cookie->ref, &ref);
-	trace_fscache_cookie(cookie->debug_id, ref + 1, where);
-	return cookie;
-}
-EXPORT_SYMBOL(fscache_get_cookie);
-
-/*
- * Ask the cache to effect invalidation of a cookie.
- */
-static void fscache_perform_invalidation(struct fscache_cookie *cookie)
-{
-	if (!cookie->volume->cache->ops->invalidate_cookie(cookie))
-		fscache_caching_failed(cookie);
-	fscache_end_cookie_access(cookie, fscache_access_invalidate_cookie_end);
-}
-
-/*
- * Invalidate an object.
- */
-void __fscache_invalidate(struct fscache_cookie *cookie,
-			  const void *aux_data, loff_t new_size,
-			  unsigned int flags)
-{
-	bool is_caching;
-
-	_enter("c=%x", cookie->debug_id);
-
-	fscache_stat(&fscache_n_invalidates);
-
-	if (WARN(test_bit(FSCACHE_COOKIE_RELINQUISHED, &cookie->flags),
-		 "Trying to invalidate relinquished cookie\n"))
-		return;
-
-	if ((flags & FSCACHE_INVAL_DIO_WRITE) &&
-	    test_and_set_bit(FSCACHE_COOKIE_DISABLED, &cookie->flags))
-		return;
-
-	spin_lock(&cookie->lock);
-	set_bit(FSCACHE_COOKIE_NO_DATA_TO_READ, &cookie->flags);
-	fscache_update_aux(cookie, aux_data, &new_size);
-	cookie->inval_counter++;
-	trace_fscache_invalidate(cookie, new_size);
-
-	switch (cookie->state) {
-	case FSCACHE_COOKIE_STATE_INVALIDATING: /* is_still_valid will catch it */
-	default:
-		spin_unlock(&cookie->lock);
-		_leave(" [no %u]", cookie->state);
-		return;
-
-	case FSCACHE_COOKIE_STATE_LOOKING_UP:
-		if (!test_and_set_bit(FSCACHE_COOKIE_DO_INVALIDATE, &cookie->flags))
-			__fscache_begin_cookie_access(cookie, fscache_access_invalidate_cookie);
-		fallthrough;
-	case FSCACHE_COOKIE_STATE_CREATING:
-		spin_unlock(&cookie->lock);
-		_leave(" [look %x]", cookie->inval_counter);
-		return;
-
-	case FSCACHE_COOKIE_STATE_ACTIVE:
-		is_caching = fscache_begin_cookie_access(
-			cookie, fscache_access_invalidate_cookie);
-		if (is_caching)
-			__fscache_set_cookie_state(cookie, FSCACHE_COOKIE_STATE_INVALIDATING);
-		spin_unlock(&cookie->lock);
-		wake_up_cookie_state(cookie);
-
-		if (is_caching)
-			fscache_queue_cookie(cookie, fscache_cookie_get_inval_work);
-		_leave(" [inv]");
-		return;
-	}
-}
-EXPORT_SYMBOL(__fscache_invalidate);
-
-#ifdef CONFIG_PROC_FS
-/*
- * Generate a list of extant cookies in /proc/fs/fscache/cookies
- */
-static int fscache_cookies_seq_show(struct seq_file *m, void *v)
-{
-	struct fscache_cookie *cookie;
-	unsigned int keylen = 0, auxlen = 0;
-	u8 *p;
-
-	if (v == &fscache_cookies) {
-		seq_puts(m,
-			 "COOKIE   VOLUME   REF ACT ACC S FL DEF             \n"
-			 "======== ======== === === === = == ================\n"
-			 );
-		return 0;
-	}
-
-	cookie = list_entry(v, struct fscache_cookie, proc_link);
-
-	seq_printf(m,
-		   "%08x %08x %3d %3d %3d %c %02lx",
-		   cookie->debug_id,
-		   cookie->volume->debug_id,
-		   refcount_read(&cookie->ref),
-		   atomic_read(&cookie->n_active),
-		   atomic_read(&cookie->n_accesses),
-		   fscache_cookie_states[cookie->state],
-		   cookie->flags);
-
-	keylen = cookie->key_len;
-	auxlen = cookie->aux_len;
-
-	if (keylen > 0 || auxlen > 0) {
-		seq_puts(m, " ");
-		p = keylen <= sizeof(cookie->inline_key) ?
-			cookie->inline_key : cookie->key;
-		for (; keylen > 0; keylen--)
-			seq_printf(m, "%02x", *p++);
-		if (auxlen > 0) {
-			seq_puts(m, ", ");
-			p = auxlen <= sizeof(cookie->inline_aux) ?
-				cookie->inline_aux : cookie->aux;
-			for (; auxlen > 0; auxlen--)
-				seq_printf(m, "%02x", *p++);
-		}
-	}
-
-	seq_puts(m, "\n");
-	return 0;
-}
-
-static void *fscache_cookies_seq_start(struct seq_file *m, loff_t *_pos)
-	__acquires(fscache_cookies_lock)
-{
-	read_lock(&fscache_cookies_lock);
-	return seq_list_start_head(&fscache_cookies, *_pos);
-}
-
-static void *fscache_cookies_seq_next(struct seq_file *m, void *v, loff_t *_pos)
-{
-	return seq_list_next(v, &fscache_cookies, _pos);
-}
-
-static void fscache_cookies_seq_stop(struct seq_file *m, void *v)
-	__releases(rcu)
-{
-	read_unlock(&fscache_cookies_lock);
-}
-
-
-const struct seq_operations fscache_cookies_seq_ops = {
-	.start  = fscache_cookies_seq_start,
-	.next   = fscache_cookies_seq_next,
-	.stop   = fscache_cookies_seq_stop,
-	.show   = fscache_cookies_seq_show,
-};
-#endif