1/* Global fscache object list maintainer and viewer
2 *
3 * Copyright (C) 2009 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public Licence
8 * as published by the Free Software Foundation; either version
9 * 2 of the Licence, or (at your option) any later version.
10 */
11
12#define FSCACHE_DEBUG_LEVEL COOKIE
13#include <linux/module.h>
14#include <linux/seq_file.h>
15#include <linux/slab.h>
16#include <linux/key.h>
17#include <keys/user-type.h>
18#include "internal.h"
19
20static struct rb_root fscache_object_list;
21static DEFINE_RWLOCK(fscache_object_list_lock);
22
23struct fscache_objlist_data {
24	unsigned long	config;		/* display configuration */
25#define FSCACHE_OBJLIST_CONFIG_KEY	0x00000001	/* show object keys */
26#define FSCACHE_OBJLIST_CONFIG_AUX	0x00000002	/* show object auxdata */
27#define FSCACHE_OBJLIST_CONFIG_COOKIE	0x00000004	/* show objects with cookies */
28#define FSCACHE_OBJLIST_CONFIG_NOCOOKIE	0x00000008	/* show objects without cookies */
29#define FSCACHE_OBJLIST_CONFIG_BUSY	0x00000010	/* show busy objects */
30#define FSCACHE_OBJLIST_CONFIG_IDLE	0x00000020	/* show idle objects */
31#define FSCACHE_OBJLIST_CONFIG_PENDWR	0x00000040	/* show objects with pending writes */
32#define FSCACHE_OBJLIST_CONFIG_NOPENDWR	0x00000080	/* show objects without pending writes */
33#define FSCACHE_OBJLIST_CONFIG_READS	0x00000100	/* show objects with active reads */
34#define FSCACHE_OBJLIST_CONFIG_NOREADS	0x00000200	/* show objects without active reads */
35#define FSCACHE_OBJLIST_CONFIG_EVENTS	0x00000400	/* show objects with events */
36#define FSCACHE_OBJLIST_CONFIG_NOEVENTS	0x00000800	/* show objects without no events */
37#define FSCACHE_OBJLIST_CONFIG_WORK	0x00001000	/* show objects with work */
38#define FSCACHE_OBJLIST_CONFIG_NOWORK	0x00002000	/* show objects without work */
39
40	u8		buf[512];	/* key and aux data buffer */
41};
42
43/*
44 * Add an object to the object list
45 * - we use the address of the fscache_object structure as the key into the
46 *   tree
47 */
48void fscache_objlist_add(struct fscache_object *obj)
49{
50	struct fscache_object *xobj;
51	struct rb_node **p = &fscache_object_list.rb_node, *parent = NULL;
52
53	ASSERT(RB_EMPTY_NODE(&obj->objlist_link));
54
55	write_lock(&fscache_object_list_lock);
56
57	while (*p) {
58		parent = *p;
59		xobj = rb_entry(parent, struct fscache_object, objlist_link);
60
61		if (obj < xobj)
62			p = &(*p)->rb_left;
63		else if (obj > xobj)
64			p = &(*p)->rb_right;
65		else
66			BUG();
67	}
68
69	rb_link_node(&obj->objlist_link, parent, p);
70	rb_insert_color(&obj->objlist_link, &fscache_object_list);
71
72	write_unlock(&fscache_object_list_lock);
73}
74
75/*
76 * Remove an object from the object list.
77 */
78void fscache_objlist_remove(struct fscache_object *obj)
79{
80	if (RB_EMPTY_NODE(&obj->objlist_link))
81		return;
82
83	write_lock(&fscache_object_list_lock);
84
85	BUG_ON(RB_EMPTY_ROOT(&fscache_object_list));
86	rb_erase(&obj->objlist_link, &fscache_object_list);
87
88	write_unlock(&fscache_object_list_lock);
89}
90
91/*
92 * find the object in the tree on or after the specified index
93 */
94static struct fscache_object *fscache_objlist_lookup(loff_t *_pos)
95{
96	struct fscache_object *pobj, *obj = NULL, *minobj = NULL;
97	struct rb_node *p;
98	unsigned long pos;
99
100	if (*_pos >= (unsigned long) ERR_PTR(-ENOENT))
101		return NULL;
102	pos = *_pos;
103
104	/* banners (can't represent line 0 by pos 0 as that would involve
105	 * returning a NULL pointer) */
106	if (pos == 0)
107		return (struct fscache_object *)(long)++(*_pos);
108	if (pos < 3)
109		return (struct fscache_object *)pos;
110
111	pobj = (struct fscache_object *)pos;
112	p = fscache_object_list.rb_node;
113	while (p) {
114		obj = rb_entry(p, struct fscache_object, objlist_link);
115		if (pobj < obj) {
116			if (!minobj || minobj > obj)
117				minobj = obj;
118			p = p->rb_left;
119		} else if (pobj > obj) {
120			p = p->rb_right;
121		} else {
122			minobj = obj;
123			break;
124		}
125		obj = NULL;
126	}
127
128	if (!minobj)
129		*_pos = (unsigned long) ERR_PTR(-ENOENT);
130	else if (minobj != obj)
131		*_pos = (unsigned long) minobj;
132	return minobj;
133}
134
135/*
136 * set up the iterator to start reading from the first line
137 */
138static void *fscache_objlist_start(struct seq_file *m, loff_t *_pos)
139	__acquires(&fscache_object_list_lock)
140{
141	read_lock(&fscache_object_list_lock);
142	return fscache_objlist_lookup(_pos);
143}
144
145/*
146 * move to the next line
147 */
148static void *fscache_objlist_next(struct seq_file *m, void *v, loff_t *_pos)
149{
150	(*_pos)++;
151	return fscache_objlist_lookup(_pos);
152}
153
154/*
155 * clean up after reading
156 */
157static void fscache_objlist_stop(struct seq_file *m, void *v)
158	__releases(&fscache_object_list_lock)
159{
160	read_unlock(&fscache_object_list_lock);
161}
162
163/*
164 * display an object
165 */
166static int fscache_objlist_show(struct seq_file *m, void *v)
167{
168	struct fscache_objlist_data *data = m->private;
169	struct fscache_object *obj = v;
170	struct fscache_cookie *cookie;
171	unsigned long config = data->config;
172	char _type[3], *type;
173	u8 *buf = data->buf, *p;
174
175	if ((unsigned long) v == 1) {
176		seq_puts(m, "OBJECT   PARENT   STAT CHLDN OPS OOP IPR EX READS"
177			 " EM EV FL S"
178			 " | NETFS_COOKIE_DEF TY FL NETFS_DATA");
179		if (config & (FSCACHE_OBJLIST_CONFIG_KEY |
180			      FSCACHE_OBJLIST_CONFIG_AUX))
181			seq_puts(m, "       ");
182		if (config & FSCACHE_OBJLIST_CONFIG_KEY)
183			seq_puts(m, "OBJECT_KEY");
184		if ((config & (FSCACHE_OBJLIST_CONFIG_KEY |
185			       FSCACHE_OBJLIST_CONFIG_AUX)) ==
186		    (FSCACHE_OBJLIST_CONFIG_KEY | FSCACHE_OBJLIST_CONFIG_AUX))
187			seq_puts(m, ", ");
188		if (config & FSCACHE_OBJLIST_CONFIG_AUX)
189			seq_puts(m, "AUX_DATA");
190		seq_puts(m, "\n");
191		return 0;
192	}
193
194	if ((unsigned long) v == 2) {
195		seq_puts(m, "======== ======== ==== ===== === === === == ====="
196			 " == == == ="
197			 " | ================ == == ================");
198		if (config & (FSCACHE_OBJLIST_CONFIG_KEY |
199			      FSCACHE_OBJLIST_CONFIG_AUX))
200			seq_puts(m, " ================");
201		seq_puts(m, "\n");
202		return 0;
203	}
204
205	/* filter out any unwanted objects */
206#define FILTER(criterion, _yes, _no)					\
207	do {								\
208		unsigned long yes = FSCACHE_OBJLIST_CONFIG_##_yes;	\
209		unsigned long no = FSCACHE_OBJLIST_CONFIG_##_no;	\
210		if (criterion) {					\
211			if (!(config & yes))				\
212				return 0;				\
213		} else {						\
214			if (!(config & no))				\
215				return 0;				\
216		}							\
217	} while(0)
218
219	cookie = obj->cookie;
220	if (~config) {
221		FILTER(cookie->def,
222		       COOKIE, NOCOOKIE);
223		FILTER(fscache_object_is_active(obj) ||
224		       obj->n_ops != 0 ||
225		       obj->n_obj_ops != 0 ||
226		       obj->flags ||
227		       !list_empty(&obj->dependents),
228		       BUSY, IDLE);
229		FILTER(test_bit(FSCACHE_OBJECT_PENDING_WRITE, &obj->flags),
230		       PENDWR, NOPENDWR);
231		FILTER(atomic_read(&obj->n_reads),
232		       READS, NOREADS);
233		FILTER(obj->events & obj->event_mask,
234		       EVENTS, NOEVENTS);
235		FILTER(work_busy(&obj->work), WORK, NOWORK);
236	}
237
238	seq_printf(m,
239		   "%8x %8x %s %5u %3u %3u %3u %2u %5u %2lx %2lx %2lx %1x | ",
240		   obj->debug_id,
241		   obj->parent ? obj->parent->debug_id : -1,
242		   obj->state->short_name,
243		   obj->n_children,
244		   obj->n_ops,
245		   obj->n_obj_ops,
246		   obj->n_in_progress,
247		   obj->n_exclusive,
248		   atomic_read(&obj->n_reads),
249		   obj->event_mask,
250		   obj->events,
251		   obj->flags,
252		   work_busy(&obj->work));
253
254	if (fscache_use_cookie(obj)) {
255		uint16_t keylen = 0, auxlen = 0;
256
257		switch (cookie->def->type) {
258		case 0:
259			type = "IX";
260			break;
261		case 1:
262			type = "DT";
263			break;
264		default:
265			sprintf(_type, "%02u", cookie->def->type);
266			type = _type;
267			break;
268		}
269
270		seq_printf(m, "%-16s %s %2lx %16p",
271			   cookie->def->name,
272			   type,
273			   cookie->flags,
274			   cookie->netfs_data);
275
276		if (cookie->def->get_key &&
277		    config & FSCACHE_OBJLIST_CONFIG_KEY)
278			keylen = cookie->def->get_key(cookie->netfs_data,
279						      buf, 400);
280
281		if (cookie->def->get_aux &&
282		    config & FSCACHE_OBJLIST_CONFIG_AUX)
283			auxlen = cookie->def->get_aux(cookie->netfs_data,
284						      buf + keylen, 512 - keylen);
285		fscache_unuse_cookie(obj);
286
287		if (keylen > 0 || auxlen > 0) {
288			seq_puts(m, " ");
289			for (p = buf; keylen > 0; keylen--)
290				seq_printf(m, "%02x", *p++);
291			if (auxlen > 0) {
292				if (config & FSCACHE_OBJLIST_CONFIG_KEY)
293					seq_puts(m, ", ");
294				for (; auxlen > 0; auxlen--)
295					seq_printf(m, "%02x", *p++);
296			}
297		}
298
299		seq_puts(m, "\n");
300	} else {
301		seq_puts(m, "<no_netfs>\n");
302	}
303	return 0;
304}
305
306static const struct seq_operations fscache_objlist_ops = {
307	.start		= fscache_objlist_start,
308	.stop		= fscache_objlist_stop,
309	.next		= fscache_objlist_next,
310	.show		= fscache_objlist_show,
311};
312
313/*
314 * get the configuration for filtering the list
315 */
316static void fscache_objlist_config(struct fscache_objlist_data *data)
317{
318#ifdef CONFIG_KEYS
319	struct user_key_payload *confkey;
320	unsigned long config;
321	struct key *key;
322	const char *buf;
323	int len;
324
325	key = request_key(&key_type_user, "fscache:objlist", NULL);
326	if (IS_ERR(key))
327		goto no_config;
328
329	config = 0;
330	rcu_read_lock();
331
332	confkey = key->payload.data;
333	buf = confkey->data;
334
335	for (len = confkey->datalen - 1; len >= 0; len--) {
336		switch (buf[len]) {
337		case 'K': config |= FSCACHE_OBJLIST_CONFIG_KEY;		break;
338		case 'A': config |= FSCACHE_OBJLIST_CONFIG_AUX;		break;
339		case 'C': config |= FSCACHE_OBJLIST_CONFIG_COOKIE;	break;
340		case 'c': config |= FSCACHE_OBJLIST_CONFIG_NOCOOKIE;	break;
341		case 'B': config |= FSCACHE_OBJLIST_CONFIG_BUSY;	break;
342		case 'b': config |= FSCACHE_OBJLIST_CONFIG_IDLE;	break;
343		case 'W': config |= FSCACHE_OBJLIST_CONFIG_PENDWR;	break;
344		case 'w': config |= FSCACHE_OBJLIST_CONFIG_NOPENDWR;	break;
345		case 'R': config |= FSCACHE_OBJLIST_CONFIG_READS;	break;
346		case 'r': config |= FSCACHE_OBJLIST_CONFIG_NOREADS;	break;
347		case 'S': config |= FSCACHE_OBJLIST_CONFIG_WORK;	break;
348		case 's': config |= FSCACHE_OBJLIST_CONFIG_NOWORK;	break;
349		}
350	}
351
352	rcu_read_unlock();
353	key_put(key);
354
355	if (!(config & (FSCACHE_OBJLIST_CONFIG_COOKIE | FSCACHE_OBJLIST_CONFIG_NOCOOKIE)))
356	    config   |= FSCACHE_OBJLIST_CONFIG_COOKIE | FSCACHE_OBJLIST_CONFIG_NOCOOKIE;
357	if (!(config & (FSCACHE_OBJLIST_CONFIG_BUSY | FSCACHE_OBJLIST_CONFIG_IDLE)))
358	    config   |= FSCACHE_OBJLIST_CONFIG_BUSY | FSCACHE_OBJLIST_CONFIG_IDLE;
359	if (!(config & (FSCACHE_OBJLIST_CONFIG_PENDWR | FSCACHE_OBJLIST_CONFIG_NOPENDWR)))
360	    config   |= FSCACHE_OBJLIST_CONFIG_PENDWR | FSCACHE_OBJLIST_CONFIG_NOPENDWR;
361	if (!(config & (FSCACHE_OBJLIST_CONFIG_READS | FSCACHE_OBJLIST_CONFIG_NOREADS)))
362	    config   |= FSCACHE_OBJLIST_CONFIG_READS | FSCACHE_OBJLIST_CONFIG_NOREADS;
363	if (!(config & (FSCACHE_OBJLIST_CONFIG_EVENTS | FSCACHE_OBJLIST_CONFIG_NOEVENTS)))
364	    config   |= FSCACHE_OBJLIST_CONFIG_EVENTS | FSCACHE_OBJLIST_CONFIG_NOEVENTS;
365	if (!(config & (FSCACHE_OBJLIST_CONFIG_WORK | FSCACHE_OBJLIST_CONFIG_NOWORK)))
366	    config   |= FSCACHE_OBJLIST_CONFIG_WORK | FSCACHE_OBJLIST_CONFIG_NOWORK;
367
368	data->config = config;
369	return;
370
371no_config:
372#endif
373	data->config = ULONG_MAX;
374}
375
376/*
377 * open "/proc/fs/fscache/objects" to provide a list of active objects
378 * - can be configured by a user-defined key added to the caller's keyrings
379 */
380static int fscache_objlist_open(struct inode *inode, struct file *file)
381{
382	struct fscache_objlist_data *data;
383
384	data = __seq_open_private(file, &fscache_objlist_ops, sizeof(*data));
385	if (!data)
386		return -ENOMEM;
387
388	/* get the configuration key */
389	fscache_objlist_config(data);
390
391	return 0;
392}
393
394/*
395 * clean up on close
396 */
397static int fscache_objlist_release(struct inode *inode, struct file *file)
398{
399	struct seq_file *m = file->private_data;
400
401	kfree(m->private);
402	m->private = NULL;
403	return seq_release(inode, file);
404}
405
406const struct file_operations fscache_objlist_fops = {
407	.owner		= THIS_MODULE,
408	.open		= fscache_objlist_open,
409	.read		= seq_read,
410	.llseek		= seq_lseek,
411	.release	= fscache_objlist_release,
412};
413