From a18feb55769b705a44c4107786c4045eae2e87b6 Mon Sep 17 00:00:00 2001
From: David Howells <dhowells@redhat.com>
Date: Wed, 4 Apr 2018 13:41:27 +0100
Subject: fscache: Add tracepoints

Add some tracepoints to fscache:

 (*) fscache_cookie - Tracks a cookie's usage count.

 (*) fscache_netfs - Logs registration of a network filesystem, including
     the pointer to the cookie allocated.

 (*) fscache_acquire - Logs cookie acquisition.

 (*) fscache_relinquish - Logs cookie relinquishment.

 (*) fscache_enable - Logs enablement of a cookie.

 (*) fscache_disable - Logs disablement of a cookie.

 (*) fscache_osm - Tracks execution of states in the object state machine.

and cachefiles:

 (*) cachefiles_ref - Tracks a cachefiles object's usage count.

 (*) cachefiles_lookup - Logs result of lookup_one_len().

 (*) cachefiles_mkdir - Logs result of vfs_mkdir().

 (*) cachefiles_create - Logs result of vfs_create().

 (*) cachefiles_unlink - Logs calls to vfs_unlink().

 (*) cachefiles_rename - Logs calls to vfs_rename().

 (*) cachefiles_mark_active - Logs an object becoming active.

 (*) cachefiles_wait_active - Logs a wait for an old object to be
     destroyed.

 (*) cachefiles_mark_inactive - Logs an object becoming inactive.

 (*) cachefiles_mark_buried - Logs the burial of an object.

Signed-off-by: David Howells <dhowells@redhat.com>
---
 include/trace/events/cachefiles.h | 325 ++++++++++++++++++++++++++++++++++++++
 include/trace/events/fscache.h    | 277 ++++++++++++++++++++++++++++++++
 2 files changed, 602 insertions(+)
 create mode 100644 include/trace/events/cachefiles.h
 create mode 100644 include/trace/events/fscache.h

(limited to 'include/trace')

diff --git a/include/trace/events/cachefiles.h b/include/trace/events/cachefiles.h
new file mode 100644
index 000000000000..aa86e7dba511
--- /dev/null
+++ b/include/trace/events/cachefiles.h
@@ -0,0 +1,325 @@
+/* CacheFiles tracepoints
+ *
+ * Copyright (C) 2016 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 Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM cachefiles
+
+#if !defined(_TRACE_CACHEFILES_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_CACHEFILES_H
+
+#include <linux/tracepoint.h>
+
+/*
+ * Define enums for tracing information.
+ */
+#ifndef __CACHEFILES_DECLARE_TRACE_ENUMS_ONCE_ONLY
+#define __CACHEFILES_DECLARE_TRACE_ENUMS_ONCE_ONLY
+
+enum cachefiles_obj_ref_trace {
+	cachefiles_obj_put_wait_retry = fscache_obj_ref__nr_traces,
+	cachefiles_obj_put_wait_timeo,
+	cachefiles_obj_ref__nr_traces
+};
+
+#endif
+
+/*
+ * Define enum -> string mappings for display.
+ */
+#define cachefiles_obj_kill_traces				\
+	EM(FSCACHE_OBJECT_IS_STALE,	"stale")		\
+	EM(FSCACHE_OBJECT_NO_SPACE,	"no_space")		\
+	EM(FSCACHE_OBJECT_WAS_RETIRED,	"was_retired")		\
+	E_(FSCACHE_OBJECT_WAS_CULLED,	"was_culled")
+
+#define cachefiles_obj_ref_traces					\
+	EM(fscache_obj_get_add_to_deps,		"GET add_to_deps")	\
+	EM(fscache_obj_get_queue,		"GET queue")		\
+	EM(fscache_obj_put_alloc_fail,		"PUT alloc_fail")	\
+	EM(fscache_obj_put_attach_fail,		"PUT attach_fail")	\
+	EM(fscache_obj_put_drop_obj,		"PUT drop_obj")		\
+	EM(fscache_obj_put_enq_dep,		"PUT enq_dep")		\
+	EM(fscache_obj_put_queue,		"PUT queue")		\
+	EM(fscache_obj_put_work,		"PUT work")		\
+	EM(cachefiles_obj_put_wait_retry,	"PUT wait_retry")	\
+	E_(cachefiles_obj_put_wait_timeo,	"PUT wait_timeo")
+
+/*
+ * Export enum symbols via userspace.
+ */
+#undef EM
+#undef E_
+#define EM(a, b) TRACE_DEFINE_ENUM(a);
+#define E_(a, b) TRACE_DEFINE_ENUM(a);
+
+cachefiles_obj_kill_traces;
+cachefiles_obj_ref_traces;
+
+/*
+ * Now redefine the EM() and E_() macros to map the enums to the strings that
+ * will be printed in the output.
+ */
+#undef EM
+#undef E_
+#define EM(a, b)	{ a, b },
+#define E_(a, b)	{ a, b }
+
+
+TRACE_EVENT(cachefiles_ref,
+	    TP_PROTO(struct cachefiles_object *obj,
+		     struct fscache_cookie *cookie,
+		     enum cachefiles_obj_ref_trace why,
+		     int usage),
+
+	    TP_ARGS(obj, cookie, why, usage),
+
+	    /* Note that obj may be NULL */
+	    TP_STRUCT__entry(
+		    __field(struct cachefiles_object *,		obj		)
+		    __field(struct fscache_cookie *,		cookie		)
+		    __field(enum cachefiles_obj_ref_trace,	why		)
+		    __field(int,				usage		)
+			     ),
+
+	    TP_fast_assign(
+		    __entry->obj	= obj;
+		    __entry->cookie	= cookie;
+		    __entry->usage	= usage;
+		    __entry->why	= why;
+			   ),
+
+	    TP_printk("c=%p o=%p u=%d %s",
+		      __entry->cookie, __entry->obj, __entry->usage,
+		      __print_symbolic(__entry->why, cachefiles_obj_ref_traces))
+	    );
+
+TRACE_EVENT(cachefiles_lookup,
+	    TP_PROTO(struct cachefiles_object *obj,
+		     struct dentry *de,
+		     struct inode *inode),
+
+	    TP_ARGS(obj, de, inode),
+
+	    TP_STRUCT__entry(
+		    __field(struct cachefiles_object *,	obj	)
+		    __field(struct dentry *,		de	)
+		    __field(struct inode *,		inode	)
+			     ),
+
+	    TP_fast_assign(
+		    __entry->obj	= obj;
+		    __entry->de		= de;
+		    __entry->inode	= inode;
+			   ),
+
+	    TP_printk("o=%p d=%p i=%p",
+		      __entry->obj, __entry->de, __entry->inode)
+	    );
+
+TRACE_EVENT(cachefiles_mkdir,
+	    TP_PROTO(struct cachefiles_object *obj,
+		     struct dentry *de, int ret),
+
+	    TP_ARGS(obj, de, ret),
+
+	    TP_STRUCT__entry(
+		    __field(struct cachefiles_object *,	obj	)
+		    __field(struct dentry *,		de	)
+		    __field(int,			ret	)
+			     ),
+
+	    TP_fast_assign(
+		    __entry->obj	= obj;
+		    __entry->de		= de;
+		    __entry->ret	= ret;
+			   ),
+
+	    TP_printk("o=%p d=%p r=%u",
+		      __entry->obj, __entry->de, __entry->ret)
+	    );
+
+TRACE_EVENT(cachefiles_create,
+	    TP_PROTO(struct cachefiles_object *obj,
+		     struct dentry *de, int ret),
+
+	    TP_ARGS(obj, de, ret),
+
+	    TP_STRUCT__entry(
+		    __field(struct cachefiles_object *,	obj	)
+		    __field(struct dentry *,		de	)
+		    __field(int,			ret	)
+			     ),
+
+	    TP_fast_assign(
+		    __entry->obj	= obj;
+		    __entry->de		= de;
+		    __entry->ret	= ret;
+			   ),
+
+	    TP_printk("o=%p d=%p r=%u",
+		      __entry->obj, __entry->de, __entry->ret)
+	    );
+
+TRACE_EVENT(cachefiles_unlink,
+	    TP_PROTO(struct cachefiles_object *obj,
+		     struct dentry *de,
+		     enum fscache_why_object_killed why),
+
+	    TP_ARGS(obj, de, why),
+
+	    /* Note that obj may be NULL */
+	    TP_STRUCT__entry(
+		    __field(struct cachefiles_object *,	obj		)
+		    __field(struct dentry *,		de		)
+		    __field(enum fscache_why_object_killed, why		)
+			     ),
+
+	    TP_fast_assign(
+		    __entry->obj	= obj;
+		    __entry->de		= de;
+		    __entry->why	= why;
+			   ),
+
+	    TP_printk("o=%p d=%p w=%s",
+		      __entry->obj, __entry->de,
+		      __print_symbolic(__entry->why, cachefiles_obj_kill_traces))
+	    );
+
+TRACE_EVENT(cachefiles_rename,
+	    TP_PROTO(struct cachefiles_object *obj,
+		     struct dentry *de,
+		     struct dentry *to,
+		     enum fscache_why_object_killed why),
+
+	    TP_ARGS(obj, de, to, why),
+
+	    /* Note that obj may be NULL */
+	    TP_STRUCT__entry(
+		    __field(struct cachefiles_object *,	obj		)
+		    __field(struct dentry *,		de		)
+		    __field(struct dentry *,		to		)
+		    __field(enum fscache_why_object_killed, why		)
+			     ),
+
+	    TP_fast_assign(
+		    __entry->obj	= obj;
+		    __entry->de		= de;
+		    __entry->to		= to;
+		    __entry->why	= why;
+			   ),
+
+	    TP_printk("o=%p d=%p t=%p w=%s",
+		      __entry->obj, __entry->de, __entry->to,
+		      __print_symbolic(__entry->why, cachefiles_obj_kill_traces))
+	    );
+
+TRACE_EVENT(cachefiles_mark_active,
+	    TP_PROTO(struct cachefiles_object *obj,
+		     struct dentry *de),
+
+	    TP_ARGS(obj, de),
+
+	    /* Note that obj may be NULL */
+	    TP_STRUCT__entry(
+		    __field(struct cachefiles_object *,	obj		)
+		    __field(struct dentry *,		de		)
+			     ),
+
+	    TP_fast_assign(
+		    __entry->obj	= obj;
+		    __entry->de		= de;
+			   ),
+
+	    TP_printk("o=%p d=%p",
+		      __entry->obj, __entry->de)
+	    );
+
+TRACE_EVENT(cachefiles_wait_active,
+	    TP_PROTO(struct cachefiles_object *obj,
+		     struct dentry *de,
+		     struct cachefiles_object *xobj),
+
+	    TP_ARGS(obj, de, xobj),
+
+	    /* Note that obj may be NULL */
+	    TP_STRUCT__entry(
+		    __field(struct cachefiles_object *,	obj		)
+		    __field(struct dentry *,		de		)
+		    __field(struct cachefiles_object *,	xobj		)
+		    __field(u16,			flags		)
+		    __field(u16,			fsc_flags	)
+			     ),
+
+	    TP_fast_assign(
+		    __entry->obj	= obj;
+		    __entry->de		= de;
+		    __entry->xobj	= xobj;
+		    __entry->flags	= xobj->flags;
+		    __entry->fsc_flags	= xobj->fscache.flags;
+			   ),
+
+	    TP_printk("o=%p d=%p wo=%p wf=%x wff=%x",
+		      __entry->obj, __entry->de, __entry->xobj,
+		      __entry->flags, __entry->fsc_flags)
+	    );
+
+TRACE_EVENT(cachefiles_mark_inactive,
+	    TP_PROTO(struct cachefiles_object *obj,
+		     struct dentry *de,
+		     struct inode *inode),
+
+	    TP_ARGS(obj, de, inode),
+
+	    /* Note that obj may be NULL */
+	    TP_STRUCT__entry(
+		    __field(struct cachefiles_object *,	obj		)
+		    __field(struct dentry *,		de		)
+		    __field(struct inode *,		inode		)
+			     ),
+
+	    TP_fast_assign(
+		    __entry->obj	= obj;
+		    __entry->de		= de;
+		    __entry->inode	= inode;
+			   ),
+
+	    TP_printk("o=%p d=%p i=%p",
+		      __entry->obj, __entry->de, __entry->inode)
+	    );
+
+TRACE_EVENT(cachefiles_mark_buried,
+	    TP_PROTO(struct cachefiles_object *obj,
+		     struct dentry *de,
+		     enum fscache_why_object_killed why),
+
+	    TP_ARGS(obj, de, why),
+
+	    /* Note that obj may be NULL */
+	    TP_STRUCT__entry(
+		    __field(struct cachefiles_object *,	obj		)
+		    __field(struct dentry *,		de		)
+		    __field(enum fscache_why_object_killed, why		)
+			     ),
+
+	    TP_fast_assign(
+		    __entry->obj	= obj;
+		    __entry->de		= de;
+		    __entry->why	= why;
+			   ),
+
+	    TP_printk("o=%p d=%p w=%s",
+		      __entry->obj, __entry->de,
+		      __print_symbolic(__entry->why, cachefiles_obj_kill_traces))
+	    );
+
+#endif /* _TRACE_CACHEFILES_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>
diff --git a/include/trace/events/fscache.h b/include/trace/events/fscache.h
new file mode 100644
index 000000000000..99f5355d6281
--- /dev/null
+++ b/include/trace/events/fscache.h
@@ -0,0 +1,277 @@
+/* FS-Cache tracepoints
+ *
+ * Copyright (C) 2016 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 Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM fscache
+
+#if !defined(_TRACE_FSCACHE_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_FSCACHE_H
+
+#include <linux/fscache.h>
+#include <linux/tracepoint.h>
+
+/*
+ * Define enums for tracing information.
+ */
+#ifndef __FSCACHE_DECLARE_TRACE_ENUMS_ONCE_ONLY
+#define __FSCACHE_DECLARE_TRACE_ENUMS_ONCE_ONLY
+
+enum fscache_cookie_trace {
+	fscache_cookie_get_acquire_parent,
+	fscache_cookie_get_attach_object,
+	fscache_cookie_get_register_netfs,
+	fscache_cookie_put_acquire_nobufs,
+	fscache_cookie_put_relinquish,
+	fscache_cookie_put_object,
+	fscache_cookie_put_parent,
+};
+
+#endif
+
+/*
+ * Declare tracing information enums and their string mappings for display.
+ */
+#define fscache_cookie_traces						\
+	EM(fscache_cookie_get_acquire_parent,	"GET prn")		\
+	EM(fscache_cookie_get_attach_object,	"GET obj")		\
+	EM(fscache_cookie_get_register_netfs,	"GET net")		\
+	EM(fscache_cookie_put_acquire_nobufs,	"PUT nbf")		\
+	EM(fscache_cookie_put_relinquish,	"PUT rlq")		\
+	EM(fscache_cookie_put_object,		"PUT obj")		\
+	E_(fscache_cookie_put_parent,		"PUT prn")
+
+/*
+ * Export enum symbols via userspace.
+ */
+#undef EM
+#undef E_
+#define EM(a, b) TRACE_DEFINE_ENUM(a);
+#define E_(a, b) TRACE_DEFINE_ENUM(a);
+
+fscache_cookie_traces;
+
+/*
+ * Now redefine the EM() and E_() macros to map the enums to the strings that
+ * will be printed in the output.
+ */
+#undef EM
+#undef E_
+#define EM(a, b)	{ a, b },
+#define E_(a, b)	{ a, b }
+
+
+TRACE_EVENT(fscache_cookie,
+	    TP_PROTO(struct fscache_cookie *cookie,
+		     enum fscache_cookie_trace where,
+		     int usage),
+
+	    TP_ARGS(cookie, where, usage),
+
+	    TP_STRUCT__entry(
+		    __field(struct fscache_cookie *,	cookie		)
+		    __field(struct fscache_cookie *,	parent		)
+		    __field(enum fscache_cookie_trace,	where		)
+		    __field(int,			usage		)
+		    __field(int,			n_children	)
+		    __field(int,			n_active	)
+		    __field(u8,				flags		)
+			     ),
+
+	    TP_fast_assign(
+		    __entry->cookie	= cookie;
+		    __entry->parent	= cookie->parent;
+		    __entry->where	= where;
+		    __entry->usage	= usage;
+		    __entry->n_children	= atomic_read(&cookie->n_children);
+		    __entry->n_active	= atomic_read(&cookie->n_active);
+		    __entry->flags	= cookie->flags;
+			   ),
+
+	    TP_printk("%s c=%p u=%d p=%p Nc=%d Na=%d f=%02x",
+		      __print_symbolic(__entry->where, fscache_cookie_traces),
+		      __entry->cookie, __entry->usage,
+		      __entry->parent, __entry->n_children, __entry->n_active,
+		      __entry->flags)
+	    );
+
+TRACE_EVENT(fscache_netfs,
+	    TP_PROTO(struct fscache_netfs *netfs),
+
+	    TP_ARGS(netfs),
+
+	    TP_STRUCT__entry(
+		    __field(struct fscache_cookie *,	cookie		)
+		    __array(char,			name, 8		)
+			     ),
+
+	    TP_fast_assign(
+		    __entry->cookie		= netfs->primary_index;
+		    strncpy(__entry->name, netfs->name, 8);
+		    __entry->name[7]		= 0;
+			   ),
+
+	    TP_printk("c=%p n=%s",
+		      __entry->cookie, __entry->name)
+	    );
+
+TRACE_EVENT(fscache_acquire,
+	    TP_PROTO(struct fscache_cookie *cookie),
+
+	    TP_ARGS(cookie),
+
+	    TP_STRUCT__entry(
+		    __field(struct fscache_cookie *,	cookie		)
+		    __field(struct fscache_cookie *,	parent		)
+		    __array(char,			name, 8		)
+		    __field(int,			p_usage		)
+		    __field(int,			p_n_children	)
+		    __field(u8,				p_flags		)
+			     ),
+
+	    TP_fast_assign(
+		    __entry->cookie		= cookie;
+		    __entry->parent		= cookie->parent;
+		    __entry->p_usage		= atomic_read(&cookie->parent->usage);
+		    __entry->p_n_children	= atomic_read(&cookie->parent->n_children);
+		    __entry->p_flags		= cookie->parent->flags;
+		    memcpy(__entry->name, cookie->def->name, 8);
+		    __entry->name[7]		= 0;
+			   ),
+
+	    TP_printk("c=%p p=%p pu=%d pc=%d pf=%02x n=%s",
+		      __entry->cookie, __entry->parent, __entry->p_usage,
+		      __entry->p_n_children, __entry->p_flags, __entry->name)
+	    );
+
+TRACE_EVENT(fscache_relinquish,
+	    TP_PROTO(struct fscache_cookie *cookie, bool retire),
+
+	    TP_ARGS(cookie, retire),
+
+	    TP_STRUCT__entry(
+		    __field(struct fscache_cookie *,	cookie		)
+		    __field(struct fscache_cookie *,	parent		)
+		    __field(int,			usage		)
+		    __field(int,			n_children	)
+		    __field(int,			n_active	)
+		    __field(u8,				flags		)
+		    __field(bool,			retire		)
+			     ),
+
+	    TP_fast_assign(
+		    __entry->cookie	= cookie;
+		    __entry->parent	= cookie->parent;
+		    __entry->usage	= atomic_read(&cookie->usage);
+		    __entry->n_children	= atomic_read(&cookie->n_children);
+		    __entry->n_active	= atomic_read(&cookie->n_active);
+		    __entry->flags	= cookie->flags;
+		    __entry->retire	= retire;
+			   ),
+
+	    TP_printk("c=%p u=%d p=%p Nc=%d Na=%d f=%02x r=%u",
+		      __entry->cookie, __entry->usage,
+		      __entry->parent, __entry->n_children, __entry->n_active,
+		      __entry->flags, __entry->retire)
+	    );
+
+TRACE_EVENT(fscache_enable,
+	    TP_PROTO(struct fscache_cookie *cookie),
+
+	    TP_ARGS(cookie),
+
+	    TP_STRUCT__entry(
+		    __field(struct fscache_cookie *,	cookie		)
+		    __field(int,			usage		)
+		    __field(int,			n_children	)
+		    __field(int,			n_active	)
+		    __field(u8,				flags		)
+			     ),
+
+	    TP_fast_assign(
+		    __entry->cookie	= cookie;
+		    __entry->usage	= atomic_read(&cookie->usage);
+		    __entry->n_children	= atomic_read(&cookie->n_children);
+		    __entry->n_active	= atomic_read(&cookie->n_active);
+		    __entry->flags	= cookie->flags;
+			   ),
+
+	    TP_printk("c=%p u=%d Nc=%d Na=%d f=%02x",
+		      __entry->cookie, __entry->usage,
+		      __entry->n_children, __entry->n_active, __entry->flags)
+	    );
+
+TRACE_EVENT(fscache_disable,
+	    TP_PROTO(struct fscache_cookie *cookie),
+
+	    TP_ARGS(cookie),
+
+	    TP_STRUCT__entry(
+		    __field(struct fscache_cookie *,	cookie		)
+		    __field(int,			usage		)
+		    __field(int,			n_children	)
+		    __field(int,			n_active	)
+		    __field(u8,				flags		)
+			     ),
+
+	    TP_fast_assign(
+		    __entry->cookie	= cookie;
+		    __entry->usage	= atomic_read(&cookie->usage);
+		    __entry->n_children	= atomic_read(&cookie->n_children);
+		    __entry->n_active	= atomic_read(&cookie->n_active);
+		    __entry->flags	= cookie->flags;
+			   ),
+
+	    TP_printk("c=%p u=%d Nc=%d Na=%d f=%02x",
+		      __entry->cookie, __entry->usage,
+		      __entry->n_children, __entry->n_active, __entry->flags)
+	    );
+
+TRACE_EVENT(fscache_osm,
+	    TP_PROTO(struct fscache_object *object,
+		     const struct fscache_state *state,
+		     bool wait, bool oob, s8 event_num),
+
+	    TP_ARGS(object, state, wait, oob, event_num),
+
+	    TP_STRUCT__entry(
+		    __field(struct fscache_cookie *,	cookie		)
+		    __field(struct fscache_object *,	object		)
+		    __array(char,			state, 8	)
+		    __field(bool,			wait		)
+		    __field(bool,			oob		)
+		    __field(s8,				event_num	)
+			     ),
+
+	    TP_fast_assign(
+		    __entry->cookie		= object->cookie;
+		    __entry->object		= object;
+		    __entry->wait		= wait;
+		    __entry->oob		= oob;
+		    __entry->event_num		= event_num;
+		    memcpy(__entry->state, state->short_name, 8);
+			   ),
+
+	    TP_printk("c=%p o=%p %s %s%sev=%d",
+		      __entry->cookie,
+		      __entry->object,
+		      __entry->state,
+		      __print_symbolic(__entry->wait,
+				       { true,  "WAIT" },
+				       { false, "WORK" }),
+		      __print_symbolic(__entry->oob,
+				       { true,  " OOB " },
+				       { false, " " }),
+		      __entry->event_num)
+	    );
+
+#endif /* _TRACE_FSCACHE_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>
-- 
cgit v1.2.3


From 08c2e3d087840cd1e7141b62d92f3dc897147984 Mon Sep 17 00:00:00 2001
From: David Howells <dhowells@redhat.com>
Date: Wed, 4 Apr 2018 13:41:27 +0100
Subject: fscache: Add more tracepoints

Add more tracepoints to fscache, including:

 (*) fscache_page - Tracks netfs pages known to fscache.

 (*) fscache_check_page - Tracks the netfs querying whether a page is
     pending storage.

 (*) fscache_wake_cookie - Tracks cookies being woken up after a page
     completes/aborts storage in the cache.

 (*) fscache_op - Tracks operations being initialised.

 (*) fscache_wrote_page - Tracks return of the backend write_page op.

 (*) fscache_gang_lookup - Tracks lookup of pages to be stored in the write
     operation.

Signed-off-by: David Howells <dhowells@redhat.com>
---
 fs/fscache/cookie.c            |   3 +-
 fs/fscache/object.c            |   3 +-
 fs/fscache/operation.c         |  26 ++++-
 fs/fscache/page.c              |  51 ++++++++-
 include/linux/fscache-cache.h  |   3 +-
 include/trace/events/fscache.h | 252 +++++++++++++++++++++++++++++++++++++++++
 6 files changed, 330 insertions(+), 8 deletions(-)

(limited to 'include/trace')

diff --git a/fs/fscache/cookie.c b/fs/fscache/cookie.c
index 20bc3341f113..ea1f80daaff4 100644
--- a/fs/fscache/cookie.c
+++ b/fs/fscache/cookie.c
@@ -691,10 +691,11 @@ int __fscache_check_consistency(struct fscache_cookie *cookie)
 	if (!op)
 		return -ENOMEM;
 
-	fscache_operation_init(op, NULL, NULL, NULL);
+	fscache_operation_init(cookie, op, NULL, NULL, NULL);
 	op->flags = FSCACHE_OP_MYTHREAD |
 		(1 << FSCACHE_OP_WAITING) |
 		(1 << FSCACHE_OP_UNUSE_COOKIE);
+	trace_fscache_page_op(cookie, NULL, op, fscache_page_op_check_consistency);
 
 	spin_lock(&cookie->lock);
 
diff --git a/fs/fscache/object.c b/fs/fscache/object.c
index 99afe64352a5..7c0ddb7ae29a 100644
--- a/fs/fscache/object.c
+++ b/fs/fscache/object.c
@@ -982,11 +982,12 @@ static const struct fscache_state *_fscache_invalidate_object(struct fscache_obj
 	if (!op)
 		goto nomem;
 
-	fscache_operation_init(op, object->cache->ops->invalidate_object,
+	fscache_operation_init(cookie, op, object->cache->ops->invalidate_object,
 			       NULL, NULL);
 	op->flags = FSCACHE_OP_ASYNC |
 		(1 << FSCACHE_OP_EXCLUSIVE) |
 		(1 << FSCACHE_OP_UNUSE_COOKIE);
+	trace_fscache_page_op(cookie, NULL, op, fscache_page_op_invalidate);
 
 	spin_lock(&cookie->lock);
 	if (fscache_submit_exclusive_op(object, op) < 0)
diff --git a/fs/fscache/operation.c b/fs/fscache/operation.c
index de67745e1cd7..7a071e1e952d 100644
--- a/fs/fscache/operation.c
+++ b/fs/fscache/operation.c
@@ -32,7 +32,8 @@ static void fscache_operation_dummy_cancel(struct fscache_operation *op)
  * Do basic initialisation of an operation.  The caller must still set flags,
  * object and processor if needed.
  */
-void fscache_operation_init(struct fscache_operation *op,
+void fscache_operation_init(struct fscache_cookie *cookie,
+			    struct fscache_operation *op,
 			    fscache_operation_processor_t processor,
 			    fscache_operation_cancel_t cancel,
 			    fscache_operation_release_t release)
@@ -46,6 +47,7 @@ void fscache_operation_init(struct fscache_operation *op,
 	op->release = release;
 	INIT_LIST_HEAD(&op->pend_link);
 	fscache_stat(&fscache_n_op_initialised);
+	trace_fscache_op(cookie, op, fscache_op_init);
 }
 EXPORT_SYMBOL(fscache_operation_init);
 
@@ -59,6 +61,8 @@ EXPORT_SYMBOL(fscache_operation_init);
  */
 void fscache_enqueue_operation(struct fscache_operation *op)
 {
+	struct fscache_cookie *cookie = op->object->cookie;
+	
 	_enter("{OBJ%x OP%x,%u}",
 	       op->object->debug_id, op->debug_id, atomic_read(&op->usage));
 
@@ -71,12 +75,14 @@ void fscache_enqueue_operation(struct fscache_operation *op)
 	fscache_stat(&fscache_n_op_enqueue);
 	switch (op->flags & FSCACHE_OP_TYPE) {
 	case FSCACHE_OP_ASYNC:
+		trace_fscache_op(cookie, op, fscache_op_enqueue_async);
 		_debug("queue async");
 		atomic_inc(&op->usage);
 		if (!queue_work(fscache_op_wq, &op->work))
 			fscache_put_operation(op);
 		break;
 	case FSCACHE_OP_MYTHREAD:
+		trace_fscache_op(cookie, op, fscache_op_enqueue_mythread);
 		_debug("queue for caller's attention");
 		break;
 	default:
@@ -101,6 +107,8 @@ static void fscache_run_op(struct fscache_object *object,
 		wake_up_bit(&op->flags, FSCACHE_OP_WAITING);
 	if (op->processor)
 		fscache_enqueue_operation(op);
+	else
+		trace_fscache_op(object->cookie, op, fscache_op_run);
 	fscache_stat(&fscache_n_op_run);
 }
 
@@ -155,6 +163,8 @@ int fscache_submit_exclusive_op(struct fscache_object *object,
 
 	_enter("{OBJ%x OP%x},", object->debug_id, op->debug_id);
 
+	trace_fscache_op(object->cookie, op, fscache_op_submit_ex);
+
 	ASSERTCMP(op->state, ==, FSCACHE_OP_ST_INITIALISED);
 	ASSERTCMP(atomic_read(&op->usage), >, 0);
 
@@ -240,6 +250,8 @@ int fscache_submit_op(struct fscache_object *object,
 	_enter("{OBJ%x OP%x},{%u}",
 	       object->debug_id, op->debug_id, atomic_read(&op->usage));
 
+	trace_fscache_op(object->cookie, op, fscache_op_submit);
+
 	ASSERTCMP(op->state, ==, FSCACHE_OP_ST_INITIALISED);
 	ASSERTCMP(atomic_read(&op->usage), >, 0);
 
@@ -357,6 +369,8 @@ int fscache_cancel_op(struct fscache_operation *op,
 
 	_enter("OBJ%x OP%x}", op->object->debug_id, op->debug_id);
 
+	trace_fscache_op(object->cookie, op, fscache_op_cancel);
+
 	ASSERTCMP(op->state, >=, FSCACHE_OP_ST_PENDING);
 	ASSERTCMP(op->state, !=, FSCACHE_OP_ST_CANCELLED);
 	ASSERTCMP(atomic_read(&op->usage), >, 0);
@@ -419,6 +433,8 @@ void fscache_cancel_all_ops(struct fscache_object *object)
 		fscache_stat(&fscache_n_op_cancelled);
 		list_del_init(&op->pend_link);
 
+		trace_fscache_op(object->cookie, op, fscache_op_cancel_all);
+
 		ASSERTCMP(op->state, ==, FSCACHE_OP_ST_PENDING);
 		op->cancel(op);
 		op->state = FSCACHE_OP_ST_CANCELLED;
@@ -454,9 +470,11 @@ void fscache_op_complete(struct fscache_operation *op, bool cancelled)
 	spin_lock(&object->lock);
 
 	if (!cancelled) {
+		trace_fscache_op(object->cookie, op, fscache_op_completed);
 		op->state = FSCACHE_OP_ST_COMPLETE;
 	} else {
 		op->cancel(op);
+		trace_fscache_op(object->cookie, op, fscache_op_cancelled);
 		op->state = FSCACHE_OP_ST_CANCELLED;
 	}
 
@@ -488,6 +506,8 @@ void fscache_put_operation(struct fscache_operation *op)
 	if (!atomic_dec_and_test(&op->usage))
 		return;
 
+	trace_fscache_op(op->object->cookie, op, fscache_op_put);
+
 	_debug("PUT OP");
 	ASSERTIFCMP(op->state != FSCACHE_OP_ST_INITIALISED &&
 		    op->state != FSCACHE_OP_ST_COMPLETE,
@@ -563,6 +583,8 @@ void fscache_operation_gc(struct work_struct *work)
 		spin_unlock(&cache->op_gc_list_lock);
 
 		object = op->object;
+		trace_fscache_op(object->cookie, op, fscache_op_gc);
+
 		spin_lock(&object->lock);
 
 		_debug("GC DEFERRED REL OBJ%x OP%x",
@@ -601,6 +623,8 @@ void fscache_op_work_func(struct work_struct *work)
 	_enter("{OBJ%x OP%x,%d}",
 	       op->object->debug_id, op->debug_id, atomic_read(&op->usage));
 
+	trace_fscache_op(op->object->cookie, op, fscache_op_work);
+
 	ASSERT(op->processor != NULL);
 	start = jiffies;
 	op->processor(op);
diff --git a/fs/fscache/page.c b/fs/fscache/page.c
index b9f18bf4227d..810b33aced1c 100644
--- a/fs/fscache/page.c
+++ b/fs/fscache/page.c
@@ -27,6 +27,7 @@ bool __fscache_check_page_write(struct fscache_cookie *cookie, struct page *page
 	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;
 }
@@ -39,6 +40,8 @@ void __fscache_wait_on_page_write(struct fscache_cookie *cookie, struct page *pa
 {
 	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);
@@ -69,6 +72,8 @@ bool __fscache_maybe_release_page(struct fscache_cookie *cookie,
 
 	_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);
@@ -101,6 +106,7 @@ try_again:
 	}
 
 	xpage = radix_tree_delete(&cookie->stores, page->index);
+	trace_fscache_page(cookie, page, fscache_page_radix_delete);
 	spin_unlock(&cookie->stores_lock);
 
 	if (xpage) {
@@ -112,6 +118,7 @@ try_again:
 	}
 
 	wake_up_bit(&cookie->flags, 0);
+	trace_fscache_wake_cookie(cookie);
 	if (xpage)
 		put_page(xpage);
 	__fscache_uncache_page(cookie, page);
@@ -144,7 +151,7 @@ static void fscache_end_page_write(struct fscache_object *object,
 				   struct page *page)
 {
 	struct fscache_cookie *cookie;
-	struct page *xpage = NULL;
+	struct page *xpage = NULL, *val;
 
 	spin_lock(&object->lock);
 	cookie = object->cookie;
@@ -154,13 +161,24 @@ static void fscache_end_page_write(struct fscache_object *object,
 		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)
@@ -215,7 +233,8 @@ int __fscache_attr_changed(struct fscache_cookie *cookie)
 		return -ENOMEM;
 	}
 
-	fscache_operation_init(op, fscache_attr_changed_op, NULL, NULL);
+	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);
@@ -299,7 +318,7 @@ static struct fscache_retrieval *fscache_alloc_retrieval(
 		return NULL;
 	}
 
-	fscache_operation_init(&op->op, NULL,
+	fscache_operation_init(cookie, &op->op, NULL,
 			       fscache_do_cancel_retrieval,
 			       fscache_release_retrieval_op);
 	op->op.flags	= FSCACHE_OP_MYTHREAD |
@@ -370,6 +389,7 @@ int fscache_wait_for_operation_activation(struct fscache_object *object,
 		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;
@@ -391,6 +411,7 @@ check_if_dead:
 	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);
@@ -445,6 +466,7 @@ int __fscache_read_or_alloc_page(struct fscache_cookie *cookie,
 		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);
 
@@ -573,6 +595,7 @@ int __fscache_read_or_alloc_pages(struct fscache_cookie *cookie,
 	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);
 
@@ -684,6 +707,7 @@ int __fscache_alloc_page(struct fscache_cookie *cookie,
 	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);
 
@@ -813,9 +837,11 @@ again:
 	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];
@@ -825,6 +851,7 @@ again:
 			   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);
@@ -836,6 +863,7 @@ again:
 	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);
@@ -849,6 +877,7 @@ again:
 
 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;
 
@@ -887,6 +916,8 @@ void fscache_invalidate_writes(struct fscache_cookie *cookie)
 		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);
@@ -896,6 +927,7 @@ void fscache_invalidate_writes(struct fscache_cookie *cookie)
 	}
 
 	wake_up_bit(&cookie->flags, 0);
+	trace_fscache_wake_cookie(cookie);
 
 	_leave("");
 }
@@ -954,7 +986,7 @@ int __fscache_write_page(struct fscache_cookie *cookie,
 	if (!op)
 		goto nomem;
 
-	fscache_operation_init(&op->op, fscache_write_op, NULL,
+	fscache_operation_init(cookie, &op->op, fscache_write_op, NULL,
 			       fscache_release_write_op);
 	op->op.flags = FSCACHE_OP_ASYNC |
 		(1 << FSCACHE_OP_WAITING) |
@@ -964,6 +996,8 @@ int __fscache_write_page(struct fscache_cookie *cookie,
 	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);
 
@@ -975,6 +1009,8 @@ int __fscache_write_page(struct fscache_cookie *cookie,
 	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);
@@ -990,8 +1026,10 @@ int __fscache_write_page(struct fscache_cookie *cookie,
 		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
@@ -1034,6 +1072,7 @@ already_pending:
 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);
@@ -1080,6 +1119,8 @@ void __fscache_uncache_page(struct fscache_cookie *cookie, struct page *page)
 	if (!PageFsCache(page))
 		goto done;
 
+	trace_fscache_page(cookie, page, fscache_page_uncache);
+
 	/* get the object */
 	spin_lock(&cookie->lock);
 
@@ -1128,6 +1169,8 @@ void fscache_mark_page_cached(struct fscache_retrieval *op, struct page *page)
 	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;
diff --git a/include/linux/fscache-cache.h b/include/linux/fscache-cache.h
index fbe102f37074..3e764fd38d9f 100644
--- a/include/linux/fscache-cache.h
+++ b/include/linux/fscache-cache.h
@@ -135,7 +135,8 @@ extern void fscache_op_work_func(struct work_struct *work);
 extern void fscache_enqueue_operation(struct fscache_operation *);
 extern void fscache_op_complete(struct fscache_operation *, bool);
 extern void fscache_put_operation(struct fscache_operation *);
-extern void fscache_operation_init(struct fscache_operation *,
+extern void fscache_operation_init(struct fscache_cookie *,
+				   struct fscache_operation *,
 				   fscache_operation_processor_t,
 				   fscache_operation_cancel_t,
 				   fscache_operation_release_t);
diff --git a/include/trace/events/fscache.h b/include/trace/events/fscache.h
index 99f5355d6281..82c060fe6635 100644
--- a/include/trace/events/fscache.h
+++ b/include/trace/events/fscache.h
@@ -33,6 +33,53 @@ enum fscache_cookie_trace {
 	fscache_cookie_put_parent,
 };
 
+enum fscache_page_trace {
+	fscache_page_cached,
+	fscache_page_inval,
+	fscache_page_maybe_release,
+	fscache_page_radix_clear_store,
+	fscache_page_radix_delete,
+	fscache_page_radix_insert,
+	fscache_page_radix_pend2store,
+	fscache_page_radix_set_pend,
+	fscache_page_uncache,
+	fscache_page_write,
+	fscache_page_write_end,
+	fscache_page_write_end_pend,
+	fscache_page_write_end_noc,
+	fscache_page_write_wait,
+	fscache_page_trace__nr
+};
+
+enum fscache_op_trace {
+	fscache_op_cancel,
+	fscache_op_cancel_all,
+	fscache_op_cancelled,
+	fscache_op_completed,
+	fscache_op_enqueue_async,
+	fscache_op_enqueue_mythread,
+	fscache_op_gc,
+	fscache_op_init,
+	fscache_op_put,
+	fscache_op_run,
+	fscache_op_signal,
+	fscache_op_submit,
+	fscache_op_submit_ex,
+	fscache_op_work,
+	fscache_op_trace__nr
+};
+
+enum fscache_page_op_trace {
+	fscache_page_op_alloc_one,
+	fscache_page_op_attr_changed,
+	fscache_page_op_check_consistency,
+	fscache_page_op_invalidate,
+	fscache_page_op_retr_multi,
+	fscache_page_op_retr_one,
+	fscache_page_op_write_one,
+	fscache_page_op_trace__nr
+};
+
 #endif
 
 /*
@@ -47,6 +94,47 @@ enum fscache_cookie_trace {
 	EM(fscache_cookie_put_object,		"PUT obj")		\
 	E_(fscache_cookie_put_parent,		"PUT prn")
 
+#define fscache_page_traces						\
+	EM(fscache_page_cached,			"Cached ")		\
+	EM(fscache_page_inval,			"InvalPg")		\
+	EM(fscache_page_maybe_release,		"MayRels")		\
+	EM(fscache_page_uncache,		"Uncache")		\
+	EM(fscache_page_radix_clear_store,	"RxCStr ")		\
+	EM(fscache_page_radix_delete,		"RxDel  ")		\
+	EM(fscache_page_radix_insert,		"RxIns  ")		\
+	EM(fscache_page_radix_pend2store,	"RxP2S  ")		\
+	EM(fscache_page_radix_set_pend,		"RxSPend ")		\
+	EM(fscache_page_write,			"WritePg")		\
+	EM(fscache_page_write_end,		"EndPgWr")		\
+	EM(fscache_page_write_end_pend,		"EndPgWP")		\
+	EM(fscache_page_write_end_noc,		"EndPgNC")		\
+	E_(fscache_page_write_wait,		"WtOnWrt")
+
+#define fscache_op_traces						\
+	EM(fscache_op_cancel,			"Cancel1")		\
+	EM(fscache_op_cancel_all,		"CancelA")		\
+	EM(fscache_op_cancelled,		"Canclld")		\
+	EM(fscache_op_completed,		"Complet")		\
+	EM(fscache_op_enqueue_async,		"EnqAsyn")		\
+	EM(fscache_op_enqueue_mythread,		"EnqMyTh")		\
+	EM(fscache_op_gc,			"GC     ")		\
+	EM(fscache_op_init,			"Init   ")		\
+	EM(fscache_op_put,			"Put    ")		\
+	EM(fscache_op_run,			"Run    ")		\
+	EM(fscache_op_signal,			"Signal ")		\
+	EM(fscache_op_submit,			"Submit ")		\
+	EM(fscache_op_submit_ex,		"SubmitX")		\
+	E_(fscache_op_work,			"Work   ")
+
+#define fscache_page_op_traces						\
+	EM(fscache_page_op_alloc_one,		"Alloc1 ")		\
+	EM(fscache_page_op_attr_changed,	"AttrChg")		\
+	EM(fscache_page_op_check_consistency,	"CheckCn")		\
+	EM(fscache_page_op_invalidate,		"Inval  ")		\
+	EM(fscache_page_op_retr_multi,		"RetrMul")		\
+	EM(fscache_page_op_retr_one,		"Retr1  ")		\
+	E_(fscache_page_op_write_one,		"Write1 ")
+
 /*
  * Export enum symbols via userspace.
  */
@@ -271,6 +359,170 @@ TRACE_EVENT(fscache_osm,
 		      __entry->event_num)
 	    );
 
+TRACE_EVENT(fscache_page,
+	    TP_PROTO(struct fscache_cookie *cookie, struct page *page,
+		     enum fscache_page_trace why),
+
+	    TP_ARGS(cookie, page, why),
+
+	    TP_STRUCT__entry(
+		    __field(struct fscache_cookie *,	cookie		)
+		    __field(pgoff_t,			page		)
+		    __field(enum fscache_page_trace,	why		)
+			     ),
+
+	    TP_fast_assign(
+		    __entry->cookie		= cookie;
+		    __entry->page		= page->index;
+		    __entry->why		= why;
+			   ),
+
+	    TP_printk("c=%p %s pg=%lx",
+		      __entry->cookie,
+		      __print_symbolic(__entry->why, fscache_page_traces),
+		      __entry->page)
+	    );
+
+TRACE_EVENT(fscache_check_page,
+	    TP_PROTO(struct fscache_cookie *cookie, struct page *page,
+		     void *val, int n),
+
+	    TP_ARGS(cookie, page, val, n),
+
+	    TP_STRUCT__entry(
+		    __field(struct fscache_cookie *,	cookie		)
+		    __field(void *,			page		)
+		    __field(void *,			val		)
+		    __field(int,			n		)
+			     ),
+
+	    TP_fast_assign(
+		    __entry->cookie		= cookie;
+		    __entry->page		= page;
+		    __entry->val		= val;
+		    __entry->n			= n;
+			   ),
+
+	    TP_printk("c=%p pg=%p val=%p n=%d",
+		      __entry->cookie, __entry->page, __entry->val, __entry->n)
+	    );
+
+TRACE_EVENT(fscache_wake_cookie,
+	    TP_PROTO(struct fscache_cookie *cookie),
+
+	    TP_ARGS(cookie),
+
+	    TP_STRUCT__entry(
+		    __field(struct fscache_cookie *,	cookie		)
+			     ),
+
+	    TP_fast_assign(
+		    __entry->cookie		= cookie;
+			   ),
+
+	    TP_printk("c=%p", __entry->cookie)
+	    );
+
+TRACE_EVENT(fscache_op,
+	    TP_PROTO(struct fscache_cookie *cookie, struct fscache_operation *op,
+		     enum fscache_op_trace why),
+
+	    TP_ARGS(cookie, op, why),
+
+	    TP_STRUCT__entry(
+		    __field(struct fscache_cookie *,	cookie		)
+		    __field(struct fscache_operation *,	op		)
+		    __field(enum fscache_op_trace,	why		)
+			     ),
+
+	    TP_fast_assign(
+		    __entry->cookie		= cookie;
+		    __entry->op			= op;
+		    __entry->why		= why;
+			   ),
+
+	    TP_printk("c=%p op=%p %s",
+		      __entry->cookie, __entry->op,
+		      __print_symbolic(__entry->why, fscache_op_traces))
+	    );
+
+TRACE_EVENT(fscache_page_op,
+	    TP_PROTO(struct fscache_cookie *cookie, struct page *page,
+		     struct fscache_operation *op, enum fscache_page_op_trace what),
+
+	    TP_ARGS(cookie, page, op, what),
+
+	    TP_STRUCT__entry(
+		    __field(struct fscache_cookie *,	cookie		)
+		    __field(pgoff_t,			page		)
+		    __field(struct fscache_operation *,	op		)
+		    __field(enum fscache_page_op_trace,	what		)
+			     ),
+
+	    TP_fast_assign(
+		    __entry->cookie		= cookie;
+		    __entry->page		= page ? page->index : 0;
+		    __entry->op			= op;
+		    __entry->what		= what;
+			   ),
+
+	    TP_printk("c=%p %s pg=%lx op=%p",
+		      __entry->cookie,
+		      __print_symbolic(__entry->what, fscache_page_op_traces),
+		      __entry->page, __entry->op)
+	    );
+
+TRACE_EVENT(fscache_wrote_page,
+	    TP_PROTO(struct fscache_cookie *cookie, struct page *page,
+		     struct fscache_operation *op, int ret),
+
+	    TP_ARGS(cookie, page, op, ret),
+
+	    TP_STRUCT__entry(
+		    __field(struct fscache_cookie *,	cookie		)
+		    __field(pgoff_t,			page		)
+		    __field(struct fscache_operation *,	op		)
+		    __field(int,			ret		)
+			     ),
+
+	    TP_fast_assign(
+		    __entry->cookie		= cookie;
+		    __entry->page		= page->index;
+		    __entry->op			= op;
+		    __entry->ret		= ret;
+			   ),
+
+	    TP_printk("c=%p pg=%lx op=%p ret=%d",
+		      __entry->cookie, __entry->page, __entry->op, __entry->ret)
+	    );
+
+TRACE_EVENT(fscache_gang_lookup,
+	    TP_PROTO(struct fscache_cookie *cookie, struct fscache_operation *op,
+		     void **results, int n, pgoff_t store_limit),
+
+	    TP_ARGS(cookie, op, results, n, store_limit),
+
+	    TP_STRUCT__entry(
+		    __field(struct fscache_cookie *,	cookie		)
+		    __field(struct fscache_operation *,	op		)
+		    __field(pgoff_t,			results0	)
+		    __field(int,			n		)
+		    __field(pgoff_t,			store_limit	)
+			     ),
+
+	    TP_fast_assign(
+		    __entry->cookie		= cookie;
+		    __entry->op			= op;
+		    __entry->results0		= results[0] ? ((struct page *)results[0])->index : (pgoff_t)-1;
+		    __entry->n			= n;
+		    __entry->store_limit	= store_limit;
+			   ),
+
+	    TP_printk("c=%p op=%p r0=%lx n=%d sl=%lx",
+		      __entry->cookie, __entry->op, __entry->results0, __entry->n,
+		      __entry->store_limit)
+	    );
+
 #endif /* _TRACE_FSCACHE_H */
 
 /* This part must be outside protection */
-- 
cgit v1.2.3


From ec0328e46d6e5d0f17372eb90ab8e333c2ac7ca9 Mon Sep 17 00:00:00 2001
From: David Howells <dhowells@redhat.com>
Date: Wed, 4 Apr 2018 13:41:28 +0100
Subject: fscache: Maintain a catalogue of allocated cookies

Maintain a catalogue of allocated cookies so that cookie collisions can be
handled properly.  For the moment, this just involves printing a warning
and returning a NULL cookie to the caller of fscache_acquire_cookie(), but
in future it might make sense to wait for the old cookie to finish being
cleaned up.

This requires the cookie key to be stored attached to the cookie so that we
still have the key available if the netfs relinquishes the cookie.  This is
done by an earlier patch.

The catalogue also renders redundant fscache_netfs_list (used for checking
for duplicates), so that can be removed.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Anna Schumaker <anna.schumaker@netapp.com>
Tested-by: Steve Dickson <steved@redhat.com>
---
 fs/fscache/cookie.c            | 294 +++++++++++++++++++++++++++++++++--------
 fs/fscache/internal.h          |   7 +
 fs/fscache/netfs.c             |  81 +++---------
 include/linux/fscache.h        |   8 +-
 include/trace/events/fscache.h |   8 ++
 5 files changed, 279 insertions(+), 119 deletions(-)

(limited to 'include/trace')

diff --git a/fs/fscache/cookie.c b/fs/fscache/cookie.c
index 8ca9a932d225..7dc55b93a830 100644
--- a/fs/fscache/cookie.c
+++ b/fs/fscache/cookie.c
@@ -21,6 +21,9 @@ struct kmem_cache *fscache_cookie_jar;
 
 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 int fscache_acquire_non_index_cookie(struct fscache_cookie *cookie,
 					    loff_t object_size);
 static int fscache_alloc_object(struct fscache_cache *cache,
@@ -28,6 +31,44 @@ static int fscache_alloc_object(struct fscache_cache *cache,
 static int fscache_attach_object(struct fscache_cookie *cookie,
 				 struct fscache_object *object);
 
+static void fscache_print_cookie(struct fscache_cookie *cookie, char prefix)
+{
+	struct hlist_node *object;
+	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,
+	       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-key=[%u] '", prefix, cookie->key_len);
+	k = (cookie->key_len <= sizeof(cookie->inline_key)) ?
+		cookie->inline_key : cookie->key;
+	for (loop = 0; loop < cookie->key_len; loop++)
+		pr_cont("%02x", k[loop]);
+	pr_cont("'\n");
+}
+
+void fscache_free_cookie(struct fscache_cookie *cookie)
+{
+	if (cookie) {
+		BUG_ON(!hlist_empty(&cookie->backing_objects));
+		if (cookie->aux_len > sizeof(cookie->inline_aux))
+			kfree(cookie->aux);
+		if (cookie->key_len > sizeof(cookie->inline_key))
+			kfree(cookie->key);
+		kmem_cache_free(fscache_cookie_jar, cookie);
+	}
+}
+
 /*
  * initialise an cookie jar slab element prior to any use
  */
@@ -41,6 +82,170 @@ void fscache_cookie_init_once(void *_cookie)
 	INIT_HLIST_HEAD(&cookie->backing_objects);
 }
 
+/*
+ * Set the index key in a cookie.  The cookie struct has space for a 12-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)
+{
+	unsigned long long h;
+	u32 *buf;
+	int i;
+
+	cookie->key_len = index_key_len;
+
+	if (index_key_len > sizeof(cookie->inline_key)) {
+		buf = kzalloc(index_key_len, GFP_KERNEL);
+		if (!buf)
+			return -ENOMEM;
+		cookie->key = buf;
+	} else {
+		buf = (u32 *)cookie->inline_key;
+		buf[0] = 0;
+		buf[1] = 0;
+		buf[2] = 0;
+	}
+
+	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 < (index_key_len + sizeof(u32) - 1) / sizeof(u32); i++)
+		h += buf[i];
+
+	cookie->key_hash = h ^ (h >> 32);
+	return 0;
+}
+
+static long fscache_compare_cookie(const struct fscache_cookie *a,
+				   const struct fscache_cookie *b)
+{
+	const void *ka, *kb;
+
+	if (a->key_hash != b->key_hash)
+		return (long)a->key_hash - (long)b->key_hash;
+	if (a->parent != b->parent)
+		return (long)a->parent - (long)b->parent;
+	if (a->key_len != b->key_len)
+		return (long)a->key_len - (long)b->key_len;
+	if (a->type != b->type)
+		return (long)a->type - (long)b->type;
+
+	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);
+}
+
+/*
+ * Allocate a cookie.
+ */
+struct fscache_cookie *fscache_alloc_cookie(
+	struct fscache_cookie *parent,
+	const struct fscache_cookie_def *def,
+	const void *index_key, size_t index_key_len,
+	const void *aux_data, size_t aux_data_len,
+	void *netfs_data,
+	loff_t object_size)
+{
+	struct fscache_cookie *cookie;
+
+	/* allocate and initialise a cookie */
+	cookie = kmem_cache_alloc(fscache_cookie_jar, GFP_KERNEL);
+	if (!cookie)
+		return NULL;
+
+	cookie->key_len = index_key_len;
+	cookie->aux_len = aux_data_len;
+
+	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;
+	}
+
+	atomic_set(&cookie->usage, 1);
+	atomic_set(&cookie->n_children, 0);
+
+	/* We keep the active count elevated until relinquishment to prevent an
+	 * attempt to wake up every time the object operations queue quiesces.
+	 */
+	atomic_set(&cookie->n_active, 1);
+
+	cookie->def		= def;
+	cookie->parent		= parent;
+	cookie->netfs_data	= netfs_data;
+	cookie->flags		= (1 << FSCACHE_COOKIE_NO_DATA_YET);
+	cookie->type		= def->type;
+
+	/* 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);
+	return cookie;
+
+nomem:
+	fscache_free_cookie(cookie);
+	return NULL;
+}
+
+/*
+ * Attempt to insert the new cookie into the hash.  If there's a collision, we
+ * return the old cookie if it's not in use and an error otherwise.
+ */
+struct fscache_cookie *fscache_hash_cookie(struct fscache_cookie *candidate)
+{
+	struct fscache_cookie *cursor;
+	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_compare_cookie(candidate, cursor) == 0)
+			goto collision;
+	}
+
+	__set_bit(FSCACHE_COOKIE_ACQUIRED, &candidate->flags);
+	fscache_cookie_get(candidate->parent, fscache_cookie_get_acquire_parent);
+	atomic_inc(&candidate->parent->n_children);
+	hlist_bl_add_head(&candidate->hash_link, h);
+	hlist_bl_unlock(h);
+	return candidate;
+
+collision:
+	if (test_and_set_bit(FSCACHE_COOKIE_ACQUIRED, &cursor->flags)) {
+		trace_fscache_cookie(cursor, fscache_cookie_collision,
+				     atomic_read(&cursor->usage));
+		pr_err("Duplicate cookie detected\n");
+		fscache_print_cookie(cursor, 'O');
+		fscache_print_cookie(candidate, 'N');
+		hlist_bl_unlock(h);
+		return NULL;
+	}
+
+	fscache_cookie_get(cursor, fscache_cookie_get_reacquire);
+	hlist_bl_unlock(h);
+	return cursor;
+}
+
 /*
  * request a cookie to represent an object (index, datafile, xattr, etc)
  * - parent specifies the parent object
@@ -65,7 +270,7 @@ struct fscache_cookie *__fscache_acquire_cookie(
 	loff_t object_size,
 	bool enable)
 {
-	struct fscache_cookie *cookie;
+	struct fscache_cookie *candidate, *cookie;
 
 	BUG_ON(!def);
 
@@ -95,53 +300,24 @@ struct fscache_cookie *__fscache_acquire_cookie(
 	BUG_ON(def->type == FSCACHE_COOKIE_TYPE_INDEX &&
 	       parent->type != FSCACHE_COOKIE_TYPE_INDEX);
 
-	/* allocate and initialise a cookie */
-	cookie = kmem_cache_alloc(fscache_cookie_jar, GFP_KERNEL);
-	if (!cookie) {
+	candidate = fscache_alloc_cookie(parent, def,
+					 index_key, index_key_len,
+					 aux_data, aux_data_len,
+					 netfs_data, object_size);
+	if (!candidate) {
 		fscache_stat(&fscache_n_acquires_oom);
 		_leave(" [ENOMEM]");
 		return NULL;
 	}
 
-	cookie->key_len		= index_key_len;
-	cookie->aux_len		= aux_data_len;
-
-	if (cookie->key_len <= sizeof(cookie->inline_key)) {
-		memcpy(cookie->inline_key, index_key, cookie->key_len);
-	} else {
-		cookie->key = kmemdup(index_key, cookie->key_len, GFP_KERNEL);
-		if (!cookie->key)
-			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;
+	cookie = fscache_hash_cookie(candidate);
+	if (!cookie) {
+		trace_fscache_cookie(candidate, fscache_cookie_discard, 1);
+		goto out;
 	}
 
-	atomic_set(&cookie->usage, 1);
-	atomic_set(&cookie->n_children, 0);
-
-	/* We keep the active count elevated until relinquishment to prevent an
-	 * attempt to wake up every time the object operations queue quiesces.
-	 */
-	atomic_set(&cookie->n_active, 1);
-
-	fscache_cookie_get(parent, fscache_cookie_get_acquire_parent);
-	atomic_inc(&parent->n_children);
-
-	cookie->def		= def;
-	cookie->parent		= parent;
-	cookie->netfs_data	= netfs_data;
-	cookie->flags		= (1 << FSCACHE_COOKIE_NO_DATA_YET);
-	cookie->type		= def->type;
-	
-	/* 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);
+	if (cookie == candidate)
+		candidate = NULL;
 
 	switch (cookie->type) {
 	case FSCACHE_COOKIE_TYPE_INDEX:
@@ -178,16 +354,10 @@ struct fscache_cookie *__fscache_acquire_cookie(
 	}
 
 	fscache_stat(&fscache_n_acquires_ok);
-	_leave(" = %p", cookie);
-	return cookie;
 
-nomem:
-	if (cookie->aux_len > sizeof(cookie->inline_aux))
-		kfree(cookie->aux);
-	if (cookie->key_len > sizeof(cookie->inline_key))
-		kfree(cookie->key);
-	kmem_cache_free(fscache_cookie_jar, cookie);
-	return NULL;
+out:
+	fscache_free_cookie(candidate);
+	return cookie;
 }
 EXPORT_SYMBOL(__fscache_acquire_cookie);
 
@@ -678,6 +848,22 @@ void __fscache_relinquish_cookie(struct fscache_cookie *cookie,
 }
 EXPORT_SYMBOL(__fscache_relinquish_cookie);
 
+/*
+ * 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);
+	hlist_bl_unlock(h);
+}
+
 /*
  * Drop a reference to a cookie.
  */
@@ -698,12 +884,8 @@ void fscache_cookie_put(struct fscache_cookie *cookie,
 		BUG_ON(usage < 0);
 
 		parent = cookie->parent;
-		BUG_ON(!hlist_empty(&cookie->backing_objects));
-		if (cookie->aux_len > sizeof(cookie->inline_aux))
-			kfree(cookie->aux);
-		if (cookie->key_len > sizeof(cookie->inline_key))
-			kfree(cookie->key);
-		kmem_cache_free(fscache_cookie_jar, cookie);
+		fscache_unhash_cookie(cookie);
+		fscache_free_cookie(cookie);
 
 		cookie = parent;
 		where = fscache_cookie_put_parent;
diff --git a/fs/fscache/internal.h b/fs/fscache/internal.h
index 5f905a499306..500650f938fe 100644
--- a/fs/fscache/internal.h
+++ b/fs/fscache/internal.h
@@ -49,7 +49,14 @@ extern struct fscache_cache *fscache_select_cache_for_object(
  */
 extern struct kmem_cache *fscache_cookie_jar;
 
+extern void fscache_free_cookie(struct fscache_cookie *);
 extern void fscache_cookie_init_once(void *);
+extern struct fscache_cookie *fscache_alloc_cookie(struct fscache_cookie *,
+						   const struct fscache_cookie_def *,
+						   const void *, size_t,
+						   const void *, size_t,
+						   void *, loff_t);
+extern struct fscache_cookie *fscache_hash_cookie(struct fscache_cookie *);
 extern void fscache_cookie_put(struct fscache_cookie *,
 			       enum fscache_cookie_trace);
 
diff --git a/fs/fscache/netfs.c b/fs/fscache/netfs.c
index a5998dfab7e7..c2f605483cc5 100644
--- a/fs/fscache/netfs.c
+++ b/fs/fscache/netfs.c
@@ -14,85 +14,51 @@
 #include <linux/slab.h>
 #include "internal.h"
 
-static LIST_HEAD(fscache_netfs_list);
-
 /*
  * register a network filesystem for caching
  */
 int __fscache_register_netfs(struct fscache_netfs *netfs)
 {
-	struct fscache_netfs *ptr;
-	struct fscache_cookie *cookie;
-	int ret;
+	struct fscache_cookie *candidate, *cookie;
 
 	_enter("{%s}", netfs->name);
 
-	INIT_LIST_HEAD(&netfs->link);
-
 	/* allocate a cookie for the primary index */
-	cookie = kmem_cache_zalloc(fscache_cookie_jar, GFP_KERNEL);
-
-	if (!cookie) {
+	candidate = fscache_alloc_cookie(&fscache_fsdef_index,
+					 &fscache_fsdef_netfs_def,
+					 netfs->name, strlen(netfs->name),
+					 &netfs->version, sizeof(netfs->version),
+					 netfs, 0);
+	if (!candidate) {
 		_leave(" = -ENOMEM");
 		return -ENOMEM;
 	}
 
-	cookie->key_len = strlen(netfs->name);
-	if (cookie->key_len <= sizeof(cookie->inline_key)) {
-		memcpy(cookie->inline_key, netfs->name, strlen(netfs->name));
-	} else {
-		ret = -ENOMEM;
-		cookie->key = kmemdup(netfs->name, cookie->key_len, GFP_KERNEL);
-		if (!cookie->key)
-			goto nomem;
-	}
-
-	cookie->aux_len = sizeof(netfs->version);
-	memcpy(cookie->inline_aux, &netfs->version, cookie->aux_len);
-
-	/* initialise the primary index cookie */
-	atomic_set(&cookie->usage, 1);
-	atomic_set(&cookie->n_children, 0);
-	atomic_set(&cookie->n_active, 1);
-
-	cookie->def		= &fscache_fsdef_netfs_def;
-	cookie->parent		= &fscache_fsdef_index;
-	cookie->netfs_data	= netfs;
-	cookie->flags		= 1 << FSCACHE_COOKIE_ENABLED;
-	cookie->type		= FSCACHE_COOKIE_TYPE_INDEX;
-
-	spin_lock_init(&cookie->lock);
-	spin_lock_init(&cookie->stores_lock);
-	INIT_HLIST_HEAD(&cookie->backing_objects);
+	candidate->flags = 1 << FSCACHE_COOKIE_ENABLED;
 
 	/* check the netfs type is not already present */
-	down_write(&fscache_addremove_sem);
-
-	ret = -EEXIST;
-	list_for_each_entry(ptr, &fscache_netfs_list, link) {
-		if (strcmp(ptr->name, netfs->name) == 0)
-			goto already_registered;
+	cookie = fscache_hash_cookie(candidate);
+	if (!cookie)
+		goto already_registered;
+	if (cookie != candidate) {
+		trace_fscache_cookie(candidate, fscache_cookie_discard, 1);
+		fscache_free_cookie(candidate);
 	}
 
 	fscache_cookie_get(cookie->parent, fscache_cookie_get_register_netfs);
 	atomic_inc(&cookie->parent->n_children);
 
 	netfs->primary_index = cookie;
-	list_add(&netfs->link, &fscache_netfs_list);
-	ret = 0;
 
 	pr_notice("Netfs '%s' registered for caching\n", netfs->name);
 	trace_fscache_netfs(netfs);
+	_leave(" = 0");
+	return 0;
 
 already_registered:
-	up_write(&fscache_addremove_sem);
-
-nomem:
-	if (ret < 0)
-		kmem_cache_free(fscache_cookie_jar, cookie);
-
-	_leave(" = %d", ret);
-	return ret;
+	fscache_cookie_put(candidate, fscache_cookie_put_dup_netfs);
+	_leave(" = -EEXIST");
+	return -EEXIST;
 }
 EXPORT_SYMBOL(__fscache_register_netfs);
 
@@ -104,15 +70,8 @@ void __fscache_unregister_netfs(struct fscache_netfs *netfs)
 {
 	_enter("{%s.%u}", netfs->name, netfs->version);
 
-	down_write(&fscache_addremove_sem);
-
-	list_del(&netfs->link);
 	fscache_relinquish_cookie(netfs->primary_index, NULL, false);
-
-	up_write(&fscache_addremove_sem);
-
-	pr_notice("Netfs '%s' unregistered from caching\n",
-		  netfs->name);
+	pr_notice("Netfs '%s' unregistered from caching\n", netfs->name);
 
 	_leave("");
 }
diff --git a/include/linux/fscache.h b/include/linux/fscache.h
index eb38f39cf832..84b90a79d75a 100644
--- a/include/linux/fscache.h
+++ b/include/linux/fscache.h
@@ -22,6 +22,7 @@
 #include <linux/list.h>
 #include <linux/pagemap.h>
 #include <linux/pagevec.h>
+#include <linux/list_bl.h>
 
 #if defined(CONFIG_FSCACHE) || defined(CONFIG_FSCACHE_MODULE)
 #define fscache_available() (1)
@@ -124,7 +125,6 @@ struct fscache_netfs {
 	uint32_t			version;	/* indexing version */
 	const char			*name;		/* filesystem name */
 	struct fscache_cookie		*primary_index;
-	struct list_head		link;		/* internal link */
 };
 
 /*
@@ -143,6 +143,7 @@ struct fscache_cookie {
 	struct hlist_head		backing_objects; /* object(s) backing this file/index */
 	const struct fscache_cookie_def	*def;		/* definition */
 	struct fscache_cookie		*parent;	/* parent of this entry */
+	struct hlist_bl_node		hash_link;	/* Link in hash table */
 	void				*netfs_data;	/* back pointer to netfs */
 	struct radix_tree_root		stores;		/* pages to be stored on this cookie */
 #define FSCACHE_COOKIE_PENDING_TAG	0		/* pages tag: pending write to cache */
@@ -156,11 +157,14 @@ struct fscache_cookie {
 #define FSCACHE_COOKIE_RELINQUISHED	4	/* T if cookie has been relinquished */
 #define FSCACHE_COOKIE_ENABLED		5	/* T if cookie is enabled */
 #define FSCACHE_COOKIE_ENABLEMENT_LOCK	6	/* T if cookie is being en/disabled */
-#define FSCACHE_COOKIE_AUX_UPDATED	7	/* T if the auxiliary data was updated */
+#define FSCACHE_COOKIE_AUX_UPDATED	8	/* T if the auxiliary data was updated */
+#define FSCACHE_COOKIE_ACQUIRED		9	/* T if cookie is in use */
+#define FSCACHE_COOKIE_RELINQUISHING	10	/* T if cookie is being relinquished */
 
 	u8				type;		/* Type of object */
 	u8				key_len;	/* Length of index key */
 	u8				aux_len;	/* Length of auxiliary data */
+	u32				key_hash;	/* Hash of parent, type, key, len */
 	union {
 		void			*key;		/* Index key */
 		u8			inline_key[16];	/* - If the key is short enough */
diff --git a/include/trace/events/fscache.h b/include/trace/events/fscache.h
index 82c060fe6635..686cfe997ed2 100644
--- a/include/trace/events/fscache.h
+++ b/include/trace/events/fscache.h
@@ -24,10 +24,14 @@
 #define __FSCACHE_DECLARE_TRACE_ENUMS_ONCE_ONLY
 
 enum fscache_cookie_trace {
+	fscache_cookie_collision,
+	fscache_cookie_discard,
 	fscache_cookie_get_acquire_parent,
 	fscache_cookie_get_attach_object,
+	fscache_cookie_get_reacquire,
 	fscache_cookie_get_register_netfs,
 	fscache_cookie_put_acquire_nobufs,
+	fscache_cookie_put_dup_netfs,
 	fscache_cookie_put_relinquish,
 	fscache_cookie_put_object,
 	fscache_cookie_put_parent,
@@ -86,10 +90,14 @@ enum fscache_page_op_trace {
  * Declare tracing information enums and their string mappings for display.
  */
 #define fscache_cookie_traces						\
+	EM(fscache_cookie_collision,		"*COLLISION*")		\
+	EM(fscache_cookie_discard,		"DISCARD")		\
 	EM(fscache_cookie_get_acquire_parent,	"GET prn")		\
 	EM(fscache_cookie_get_attach_object,	"GET obj")		\
+	EM(fscache_cookie_get_reacquire,	"GET raq")		\
 	EM(fscache_cookie_get_register_netfs,	"GET net")		\
 	EM(fscache_cookie_put_acquire_nobufs,	"PUT nbf")		\
+	EM(fscache_cookie_put_dup_netfs,	"PUT dnt")		\
 	EM(fscache_cookie_put_relinquish,	"PUT rlq")		\
 	EM(fscache_cookie_put_object,		"PUT obj")		\
 	E_(fscache_cookie_put_parent,		"PUT prn")
-- 
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