1 files changed, 156 insertions, 45 deletions

diff --git a/fs/fscache/cookie.c b/fs/fscache/cookie.c
index 751bc5b1cddf..cd42be646ed3 100644
--- a/fs/fscache/cookie.c
+++ b/fs/fscache/cookie.c
@@ -19,6 +19,8 @@ static atomic_t fscache_object_debug_id = ATOMIC_INIT(0);
 
 #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 int fscache_acquire_non_index_cookie(struct fscache_cookie *cookie,
 					    loff_t object_size);
@@ -29,21 +31,29 @@ static int fscache_attach_object(struct fscache_cookie *cookie,
 
 static void fscache_print_cookie(struct fscache_cookie *cookie, char prefix)
 {
-	struct hlist_node *object;
+	struct fscache_object *object;
+	struct hlist_node *o;
 	const u8 *k;
 	unsigned loop;
 
-	pr_err("%c-cookie c=%p [p=%p fl=%lx nc=%u na=%u]\n",
-	       prefix, cookie, cookie->parent, cookie->flags,
+	pr_err("%c-cookie c=%08x [p=%08x fl=%lx nc=%u na=%u]\n",
+	       prefix,
+	       cookie->debug_id,
+	       cookie->parent ? cookie->parent->debug_id : 0,
+	       cookie->flags,
 	       atomic_read(&cookie->n_children),
 	       atomic_read(&cookie->n_active));
-	pr_err("%c-cookie d=%p n=%p\n",
-	       prefix, cookie->def, cookie->netfs_data);
-
-	object = READ_ONCE(cookie->backing_objects.first);
-	if (object)
-		pr_err("%c-cookie o=%p\n",
-		       prefix, hlist_entry(object, struct fscache_object, cookie_link));
+	pr_err("%c-cookie d=%p{%s} n=%p\n",
+	       prefix,
+	       cookie->def,
+	       cookie->def ? cookie->def->name : "?",
+	       cookie->netfs_data);
+
+	o = READ_ONCE(cookie->backing_objects.first);
+	if (o) {
+		object = hlist_entry(o, struct fscache_object, cookie_link);
+		pr_err("%c-cookie o=%u\n", prefix, object->debug_id);
+	}
 
 	pr_err("%c-key=[%u] '", prefix, cookie->key_len);
 	k = (cookie->key_len <= sizeof(cookie->inline_key)) ?
@@ -57,6 +67,9 @@ void fscache_free_cookie(struct fscache_cookie *cookie)
 {
 	if (cookie) {
 		BUG_ON(!hlist_empty(&cookie->backing_objects));
+		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))
@@ -74,10 +87,8 @@ void fscache_free_cookie(struct fscache_cookie *cookie)
 static int fscache_set_key(struct fscache_cookie *cookie,
 			   const void *index_key, size_t index_key_len)
 {
-	unsigned long long h;
 	u32 *buf;
 	int bufs;
-	int i;
 
 	bufs = DIV_ROUND_UP(index_key_len, sizeof(*buf));
 
@@ -91,17 +102,7 @@ static int fscache_set_key(struct fscache_cookie *cookie,
 	}
 
 	memcpy(buf, index_key, index_key_len);
-
-	/* Calculate a hash and combine this with the length in the first word
-	 * or first half word
-	 */
-	h = (unsigned long)cookie->parent;
-	h += index_key_len + cookie->type;
-
-	for (i = 0; i < bufs; i++)
-		h += buf[i];
-
-	cookie->key_hash = h ^ (h >> 32);
+	cookie->key_hash = fscache_hash(0, buf, bufs);
 	return 0;
 }
 
@@ -129,6 +130,8 @@ static long fscache_compare_cookie(const struct fscache_cookie *a,
 	return memcmp(ka, kb, a->key_len);
 }
 
+static atomic_t fscache_cookie_debug_id = ATOMIC_INIT(1);
+
 /*
  * Allocate a cookie.
  */
@@ -161,8 +164,9 @@ struct fscache_cookie *fscache_alloc_cookie(
 			goto nomem;
 	}
 
-	atomic_set(&cookie->usage, 1);
+	refcount_set(&cookie->ref, 1);
 	atomic_set(&cookie->n_children, 0);
+	cookie->debug_id = atomic_inc_return(&fscache_cookie_debug_id);
 
 	/* We keep the active count elevated until relinquishment to prevent an
 	 * attempt to wake up every time the object operations queue quiesces.
@@ -181,6 +185,10 @@ struct fscache_cookie *fscache_alloc_cookie(
 	/* radix tree insertion won't use the preallocation pool unless it's
 	 * told it may not wait */
 	INIT_RADIX_TREE(&cookie->stores, GFP_NOFS & ~__GFP_DIRECT_RECLAIM);
+
+	write_lock(&fscache_cookies_lock);
+	list_add_tail(&cookie->proc_link, &fscache_cookies);
+	write_unlock(&fscache_cookies_lock);
 	return cookie;
 
 nomem:
@@ -217,8 +225,8 @@ struct fscache_cookie *fscache_hash_cookie(struct fscache_cookie *candidate)
 
 collision:
 	if (test_and_set_bit(FSCACHE_COOKIE_ACQUIRED, &cursor->flags)) {
-		trace_fscache_cookie(cursor, fscache_cookie_collision,
-				     atomic_read(&cursor->usage));
+		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');
@@ -297,7 +305,8 @@ struct fscache_cookie *__fscache_acquire_cookie(
 
 	cookie = fscache_hash_cookie(candidate);
 	if (!cookie) {
-		trace_fscache_cookie(candidate, fscache_cookie_discard, 1);
+		trace_fscache_cookie(candidate->debug_id, 1,
+				     fscache_cookie_discard);
 		goto out;
 	}
 
@@ -355,7 +364,7 @@ void __fscache_enable_cookie(struct fscache_cookie *cookie,
 			     bool (*can_enable)(void *data),
 			     void *data)
 {
-	_enter("%p", cookie);
+	_enter("%x", cookie->debug_id);
 
 	trace_fscache_enable(cookie);
 
@@ -452,10 +461,8 @@ static int fscache_acquire_non_index_cookie(struct fscache_cookie *cookie,
 
 	/* we may be required to wait for lookup to complete at this point */
 	if (!fscache_defer_lookup) {
-		_debug("non-deferred lookup %p", &cookie->flags);
 		wait_on_bit(&cookie->flags, FSCACHE_COOKIE_LOOKING_UP,
 			    TASK_UNINTERRUPTIBLE);
-		_debug("complete");
 		if (test_bit(FSCACHE_COOKIE_UNAVAILABLE, &cookie->flags))
 			goto unavailable;
 	}
@@ -480,7 +487,7 @@ static int fscache_alloc_object(struct fscache_cache *cache,
 	struct fscache_object *object;
 	int ret;
 
-	_enter("%p,%p{%s}", cache, cookie, cookie->def->name);
+	_enter("%s,%x{%s}", cache->tag->name, cookie->debug_id, cookie->def->name);
 
 	spin_lock(&cookie->lock);
 	hlist_for_each_entry(object, &cookie->backing_objects,
@@ -600,8 +607,6 @@ static int fscache_attach_object(struct fscache_cookie *cookie,
 
 	/* Attach to the cookie.  The object already has a ref on it. */
 	hlist_add_head(&object->cookie_link, &cookie->backing_objects);
-
-	fscache_objlist_add(object);
 	ret = 0;
 
 cant_attach_object:
@@ -658,7 +663,7 @@ EXPORT_SYMBOL(__fscache_invalidate);
  */
 void __fscache_wait_on_invalidate(struct fscache_cookie *cookie)
 {
-	_enter("%p", cookie);
+	_enter("%x", cookie->debug_id);
 
 	wait_on_bit(&cookie->flags, FSCACHE_COOKIE_INVALIDATING,
 		    TASK_UNINTERRUPTIBLE);
@@ -713,7 +718,7 @@ void __fscache_disable_cookie(struct fscache_cookie *cookie,
 	struct fscache_object *object;
 	bool awaken = false;
 
-	_enter("%p,%u", cookie, invalidate);
+	_enter("%x,%u", cookie->debug_id, invalidate);
 
 	trace_fscache_disable(cookie);
 
@@ -803,8 +808,8 @@ void __fscache_relinquish_cookie(struct fscache_cookie *cookie,
 		return;
 	}
 
-	_enter("%p{%s,%p,%d},%d",
-	       cookie, cookie->def->name, cookie->netfs_data,
+	_enter("%x{%s,%d},%d",
+	       cookie->debug_id, cookie->def->name,
 	       atomic_read(&cookie->n_active), retire);
 
 	trace_fscache_relinquish(cookie, retire);
@@ -821,13 +826,12 @@ void __fscache_relinquish_cookie(struct fscache_cookie *cookie,
 	BUG_ON(!radix_tree_empty(&cookie->stores));
 
 	if (cookie->parent) {
-		ASSERTCMP(atomic_read(&cookie->parent->usage), >, 0);
+		ASSERTCMP(refcount_read(&cookie->parent->ref), >, 0);
 		ASSERTCMP(atomic_read(&cookie->parent->n_children), >, 0);
 		atomic_dec(&cookie->parent->n_children);
 	}
 
 	/* Dispose of the netfs's link to the cookie */
-	ASSERTCMP(atomic_read(&cookie->usage), >, 0);
 	fscache_cookie_put(cookie, fscache_cookie_put_relinquish);
 
 	_leave("");
@@ -857,17 +861,17 @@ void fscache_cookie_put(struct fscache_cookie *cookie,
 			enum fscache_cookie_trace where)
 {
 	struct fscache_cookie *parent;
-	int usage;
+	int ref;
 
-	_enter("%p", cookie);
+	_enter("%x", cookie->debug_id);
 
 	do {
-		usage = atomic_dec_return(&cookie->usage);
-		trace_fscache_cookie(cookie, where, usage);
+		unsigned int cookie_debug_id = cookie->debug_id;
+		bool zero = __refcount_dec_and_test(&cookie->ref, &ref);
 
-		if (usage > 0)
+		trace_fscache_cookie(cookie_debug_id, ref - 1, where);
+		if (!zero)
 			return;
-		BUG_ON(usage < 0);
 
 		parent = cookie->parent;
 		fscache_unhash_cookie(cookie);
@@ -881,6 +885,19 @@ void fscache_cookie_put(struct fscache_cookie *cookie,
 }
 
 /*
+ * Get a reference to a cookie.
+ */
+struct fscache_cookie *fscache_cookie_get(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;
+}
+
+/*
  * check the consistency between the netfs inode and the backing cache
  *
  * NOTE: it only serves no-index type
@@ -958,3 +975,97 @@ inconsistent:
 	return -ESTALE;
 }
 EXPORT_SYMBOL(__fscache_check_consistency);
+
+/*
+ * 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;
+	char _type[3], *type;
+	u8 *p;
+
+	if (v == &fscache_cookies) {
+		seq_puts(m,
+			 "COOKIE   PARENT   USAGE CHILD ACT TY FL  DEF              NETFS_DATA\n"
+			 "======== ======== ===== ===== === == === ================ ==========\n"
+			 );
+		return 0;
+	}
+
+	cookie = list_entry(v, struct fscache_cookie, proc_link);
+
+	switch (cookie->type) {
+	case 0:
+		type = "IX";
+		break;
+	case 1:
+		type = "DT";
+		break;
+	default:
+		snprintf(_type, sizeof(_type), "%02u",
+			 cookie->type);
+		type = _type;
+		break;
+	}
+
+	seq_printf(m,
+		   "%08x %08x %5u %5u %3u %s %03lx %-16s %px",
+		   cookie->debug_id,
+		   cookie->parent ? cookie->parent->debug_id : 0,
+		   refcount_read(&cookie->ref),
+		   atomic_read(&cookie->n_children),
+		   atomic_read(&cookie->n_active),
+		   type,
+		   cookie->flags,
+		   cookie->def->name,
+		   cookie->netfs_data);
+
+	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,
+};