1// SPDX-License-Identifier: GPL-2.0-or-later
2/* Global fscache object list maintainer and viewer
3 *
4 * Copyright (C) 2009 Red Hat, Inc. All Rights Reserved.
5 * Written by David Howells (dhowells@redhat.com)
6 */
7
8#define FSCACHE_DEBUG_LEVEL COOKIE
9#include <linux/module.h>
10#include <linux/proc_fs.h>
11#include <linux/seq_file.h>
12#include <linux/slab.h>
13#include <linux/key.h>
14#include <keys/user-type.h>
15#include "internal.h"
16
17static struct rb_root fscache_object_list;
18static DEFINE_RWLOCK(fscache_object_list_lock);
19
20struct fscache_objlist_data {
21	unsigned long	config;		/* display configuration */
22#define FSCACHE_OBJLIST_CONFIG_KEY	0x00000001	/* show object keys */
23#define FSCACHE_OBJLIST_CONFIG_AUX	0x00000002	/* show object auxdata */
24#define FSCACHE_OBJLIST_CONFIG_COOKIE	0x00000004	/* show objects with cookies */
25#define FSCACHE_OBJLIST_CONFIG_NOCOOKIE	0x00000008	/* show objects without cookies */
26#define FSCACHE_OBJLIST_CONFIG_BUSY	0x00000010	/* show busy objects */
27#define FSCACHE_OBJLIST_CONFIG_IDLE	0x00000020	/* show idle objects */
28#define FSCACHE_OBJLIST_CONFIG_PENDWR	0x00000040	/* show objects with pending writes */
29#define FSCACHE_OBJLIST_CONFIG_NOPENDWR	0x00000080	/* show objects without pending writes */
30#define FSCACHE_OBJLIST_CONFIG_READS	0x00000100	/* show objects with active reads */
31#define FSCACHE_OBJLIST_CONFIG_NOREADS	0x00000200	/* show objects without active reads */
32#define FSCACHE_OBJLIST_CONFIG_EVENTS	0x00000400	/* show objects with events */
33#define FSCACHE_OBJLIST_CONFIG_NOEVENTS	0x00000800	/* show objects without no events */
34#define FSCACHE_OBJLIST_CONFIG_WORK	0x00001000	/* show objects with work */
35#define FSCACHE_OBJLIST_CONFIG_NOWORK	0x00002000	/* show objects without work */
36};
37
38/*
39 * Add an object to the object list
40 * - we use the address of the fscache_object structure as the key into the
41 *   tree
42 */
43void fscache_objlist_add(struct fscache_object *obj)
44{
45	struct fscache_object *xobj;
46	struct rb_node **p = &fscache_object_list.rb_node, *parent = NULL;
47
48	ASSERT(RB_EMPTY_NODE(&obj->objlist_link));
49
50	write_lock(&fscache_object_list_lock);
51
52	while (*p) {
53		parent = *p;
54		xobj = rb_entry(parent, struct fscache_object, objlist_link);
55
56		if (obj < xobj)
57			p = &(*p)->rb_left;
58		else if (obj > xobj)
59			p = &(*p)->rb_right;
60		else
61			BUG();
62	}
63
64	rb_link_node(&obj->objlist_link, parent, p);
65	rb_insert_color(&obj->objlist_link, &fscache_object_list);
66
67	write_unlock(&fscache_object_list_lock);
68}
69
70/*
71 * Remove an object from the object list.
72 */
73void fscache_objlist_remove(struct fscache_object *obj)
74{
75	if (RB_EMPTY_NODE(&obj->objlist_link))
76		return;
77
78	write_lock(&fscache_object_list_lock);
79
80	BUG_ON(RB_EMPTY_ROOT(&fscache_object_list));
81	rb_erase(&obj->objlist_link, &fscache_object_list);
82
83	write_unlock(&fscache_object_list_lock);
84}
85
86/*
87 * find the object in the tree on or after the specified index
88 */
89static struct fscache_object *fscache_objlist_lookup(loff_t *_pos)
90{
91	struct fscache_object *pobj, *obj = NULL, *minobj = NULL;
92	struct rb_node *p;
93	unsigned long pos;
94
95	if (*_pos >= (unsigned long) ERR_PTR(-ENOENT))
96		return NULL;
97	pos = *_pos;
98
99	/* banners (can't represent line 0 by pos 0 as that would involve
100	 * returning a NULL pointer) */
101	if (pos == 0)
102		return (struct fscache_object *)(long)++(*_pos);
103	if (pos < 3)
104		return (struct fscache_object *)pos;
105
106	pobj = (struct fscache_object *)pos;
107	p = fscache_object_list.rb_node;
108	while (p) {
109		obj = rb_entry(p, struct fscache_object, objlist_link);
110		if (pobj < obj) {
111			if (!minobj || minobj > obj)
112				minobj = obj;
113			p = p->rb_left;
114		} else if (pobj > obj) {
115			p = p->rb_right;
116		} else {
117			minobj = obj;
118			break;
119		}
120		obj = NULL;
121	}
122
123	if (!minobj)
124		*_pos = (unsigned long) ERR_PTR(-ENOENT);
125	else if (minobj != obj)
126		*_pos = (unsigned long) minobj;
127	return minobj;
128}
129
130/*
131 * set up the iterator to start reading from the first line
132 */
133static void *fscache_objlist_start(struct seq_file *m, loff_t *_pos)
134	__acquires(&fscache_object_list_lock)
135{
136	read_lock(&fscache_object_list_lock);
137	return fscache_objlist_lookup(_pos);
138}
139
140/*
141 * move to the next line
142 */
143static void *fscache_objlist_next(struct seq_file *m, void *v, loff_t *_pos)
144{
145	(*_pos)++;
146	return fscache_objlist_lookup(_pos);
147}
148
149/*
150 * clean up after reading
151 */
152static void fscache_objlist_stop(struct seq_file *m, void *v)
153	__releases(&fscache_object_list_lock)
154{
155	read_unlock(&fscache_object_list_lock);
156}
157
158/*
159 * display an object
160 */
161static int fscache_objlist_show(struct seq_file *m, void *v)
162{
163	struct fscache_objlist_data *data = m->private;
164	struct fscache_object *obj = v;
165	struct fscache_cookie *cookie;
166	unsigned long config = data->config;
167	char _type[3], *type;
168	u8 *p;
169
170	if ((unsigned long) v == 1) {
171		seq_puts(m, "OBJECT   PARENT   STAT CHLDN OPS OOP IPR EX READS"
172			 " EM EV FL S"
173			 " | NETFS_COOKIE_DEF TY FL NETFS_DATA");
174		if (config & (FSCACHE_OBJLIST_CONFIG_KEY |
175			      FSCACHE_OBJLIST_CONFIG_AUX))
176			seq_puts(m, "       ");
177		if (config & FSCACHE_OBJLIST_CONFIG_KEY)
178			seq_puts(m, "OBJECT_KEY");
179		if ((config & (FSCACHE_OBJLIST_CONFIG_KEY |
180			       FSCACHE_OBJLIST_CONFIG_AUX)) ==
181		    (FSCACHE_OBJLIST_CONFIG_KEY | FSCACHE_OBJLIST_CONFIG_AUX))
182			seq_puts(m, ", ");
183		if (config & FSCACHE_OBJLIST_CONFIG_AUX)
184			seq_puts(m, "AUX_DATA");
185		seq_puts(m, "\n");
186		return 0;
187	}
188
189	if ((unsigned long) v == 2) {
190		seq_puts(m, "======== ======== ==== ===== === === === == ====="
191			 " == == == ="
192			 " | ================ == == ================");
193		if (config & (FSCACHE_OBJLIST_CONFIG_KEY |
194			      FSCACHE_OBJLIST_CONFIG_AUX))
195			seq_puts(m, " ================");
196		seq_puts(m, "\n");
197		return 0;
198	}
199
200	/* filter out any unwanted objects */
201#define FILTER(criterion, _yes, _no)					\
202	do {								\
203		unsigned long yes = FSCACHE_OBJLIST_CONFIG_##_yes;	\
204		unsigned long no = FSCACHE_OBJLIST_CONFIG_##_no;	\
205		if (criterion) {					\
206			if (!(config & yes))				\
207				return 0;				\
208		} else {						\
209			if (!(config & no))				\
210				return 0;				\
211		}							\
212	} while(0)
213
214	cookie = obj->cookie;
215	if (~config) {
216		FILTER(cookie->def,
217		       COOKIE, NOCOOKIE);
218		FILTER(fscache_object_is_active(obj) ||
219		       obj->n_ops != 0 ||
220		       obj->n_obj_ops != 0 ||
221		       obj->flags ||
222		       !list_empty(&obj->dependents),
223		       BUSY, IDLE);
224		FILTER(test_bit(FSCACHE_OBJECT_PENDING_WRITE, &obj->flags),
225		       PENDWR, NOPENDWR);
226		FILTER(atomic_read(&obj->n_reads),
227		       READS, NOREADS);
228		FILTER(obj->events & obj->event_mask,
229		       EVENTS, NOEVENTS);
230		FILTER(work_busy(&obj->work), WORK, NOWORK);
231	}
232
233	seq_printf(m,
234		   "%8x %8x %s %5u %3u %3u %3u %2u %5u %2lx %2lx %2lx %1x | ",
235		   obj->debug_id,
236		   obj->parent ? obj->parent->debug_id : -1,
237		   obj->state->short_name,
238		   obj->n_children,
239		   obj->n_ops,
240		   obj->n_obj_ops,
241		   obj->n_in_progress,
242		   obj->n_exclusive,
243		   atomic_read(&obj->n_reads),
244		   obj->event_mask,
245		   obj->events,
246		   obj->flags,
247		   work_busy(&obj->work));
248
249	if (fscache_use_cookie(obj)) {
250		uint16_t keylen = 0, auxlen = 0;
251
252		switch (cookie->type) {
253		case 0:
254			type = "IX";
255			break;
256		case 1:
257			type = "DT";
258			break;
259		default:
260			snprintf(_type, sizeof(_type), "%02u",
261				 cookie->type);
262			type = _type;
263			break;
264		}
265
266		seq_printf(m, "%-16s %s %2lx %16p",
267			   cookie->def->name,
268			   type,
269			   cookie->flags,
270			   cookie->netfs_data);
271
272		if (config & FSCACHE_OBJLIST_CONFIG_KEY)
273			keylen = cookie->key_len;
274
275		if (config & FSCACHE_OBJLIST_CONFIG_AUX)
276			auxlen = cookie->aux_len;
277
278		if (keylen > 0 || auxlen > 0) {
279			seq_puts(m, " ");
280			p = keylen <= sizeof(cookie->inline_key) ?
281				cookie->inline_key : cookie->key;
282			for (; keylen > 0; keylen--)
283				seq_printf(m, "%02x", *p++);
284			if (auxlen > 0) {
285				if (config & FSCACHE_OBJLIST_CONFIG_KEY)
286					seq_puts(m, ", ");
287				p = auxlen <= sizeof(cookie->inline_aux) ?
288					cookie->inline_aux : cookie->aux;
289				for (; auxlen > 0; auxlen--)
290					seq_printf(m, "%02x", *p++);
291			}
292		}
293
294		seq_puts(m, "\n");
295		fscache_unuse_cookie(obj);
296	} else {
297		seq_puts(m, "<no_netfs>\n");
298	}
299	return 0;
300}
301
302static const struct seq_operations fscache_objlist_ops = {
303	.start		= fscache_objlist_start,
304	.stop		= fscache_objlist_stop,
305	.next		= fscache_objlist_next,
306	.show		= fscache_objlist_show,
307};
308
309/*
310 * get the configuration for filtering the list
311 */
312static void fscache_objlist_config(struct fscache_objlist_data *data)
313{
314#ifdef CONFIG_KEYS
315	const struct user_key_payload *confkey;
316	unsigned long config;
317	struct key *key;
318	const char *buf;
319	int len;
320
321	key = request_key(&key_type_user, "fscache:objlist", NULL);
322	if (IS_ERR(key))
323		goto no_config;
324
325	config = 0;
326	rcu_read_lock();
327
328	confkey = user_key_payload_rcu(key);
329	if (!confkey) {
330		/* key was revoked */
331		rcu_read_unlock();
332		key_put(key);
333		goto no_config;
334	}
335
336	buf = confkey->data;
337
338	for (len = confkey->datalen - 1; len >= 0; len--) {
339		switch (buf[len]) {
340		case 'K': config |= FSCACHE_OBJLIST_CONFIG_KEY;		break;
341		case 'A': config |= FSCACHE_OBJLIST_CONFIG_AUX;		break;
342		case 'C': config |= FSCACHE_OBJLIST_CONFIG_COOKIE;	break;
343		case 'c': config |= FSCACHE_OBJLIST_CONFIG_NOCOOKIE;	break;
344		case 'B': config |= FSCACHE_OBJLIST_CONFIG_BUSY;	break;
345		case 'b': config |= FSCACHE_OBJLIST_CONFIG_IDLE;	break;
346		case 'W': config |= FSCACHE_OBJLIST_CONFIG_PENDWR;	break;
347		case 'w': config |= FSCACHE_OBJLIST_CONFIG_NOPENDWR;	break;
348		case 'R': config |= FSCACHE_OBJLIST_CONFIG_READS;	break;
349		case 'r': config |= FSCACHE_OBJLIST_CONFIG_NOREADS;	break;
350		case 'S': config |= FSCACHE_OBJLIST_CONFIG_WORK;	break;
351		case 's': config |= FSCACHE_OBJLIST_CONFIG_NOWORK;	break;
352		}
353	}
354
355	rcu_read_unlock();
356	key_put(key);
357
358	if (!(config & (FSCACHE_OBJLIST_CONFIG_COOKIE | FSCACHE_OBJLIST_CONFIG_NOCOOKIE)))
359	    config   |= FSCACHE_OBJLIST_CONFIG_COOKIE | FSCACHE_OBJLIST_CONFIG_NOCOOKIE;
360	if (!(config & (FSCACHE_OBJLIST_CONFIG_BUSY | FSCACHE_OBJLIST_CONFIG_IDLE)))
361	    config   |= FSCACHE_OBJLIST_CONFIG_BUSY | FSCACHE_OBJLIST_CONFIG_IDLE;
362	if (!(config & (FSCACHE_OBJLIST_CONFIG_PENDWR | FSCACHE_OBJLIST_CONFIG_NOPENDWR)))
363	    config   |= FSCACHE_OBJLIST_CONFIG_PENDWR | FSCACHE_OBJLIST_CONFIG_NOPENDWR;
364	if (!(config & (FSCACHE_OBJLIST_CONFIG_READS | FSCACHE_OBJLIST_CONFIG_NOREADS)))
365	    config   |= FSCACHE_OBJLIST_CONFIG_READS | FSCACHE_OBJLIST_CONFIG_NOREADS;
366	if (!(config & (FSCACHE_OBJLIST_CONFIG_EVENTS | FSCACHE_OBJLIST_CONFIG_NOEVENTS)))
367	    config   |= FSCACHE_OBJLIST_CONFIG_EVENTS | FSCACHE_OBJLIST_CONFIG_NOEVENTS;
368	if (!(config & (FSCACHE_OBJLIST_CONFIG_WORK | FSCACHE_OBJLIST_CONFIG_NOWORK)))
369	    config   |= FSCACHE_OBJLIST_CONFIG_WORK | FSCACHE_OBJLIST_CONFIG_NOWORK;
370
371	data->config = config;
372	return;
373
374no_config:
375#endif
376	data->config = ULONG_MAX;
377}
378
379/*
380 * open "/proc/fs/fscache/objects" to provide a list of active objects
381 * - can be configured by a user-defined key added to the caller's keyrings
382 */
383static int fscache_objlist_open(struct inode *inode, struct file *file)
384{
385	struct fscache_objlist_data *data;
386
387	data = __seq_open_private(file, &fscache_objlist_ops, sizeof(*data));
388	if (!data)
389		return -ENOMEM;
390
391	/* get the configuration key */
392	fscache_objlist_config(data);
393
394	return 0;
395}
396
397/*
398 * clean up on close
399 */
400static int fscache_objlist_release(struct inode *inode, struct file *file)
401{
402	struct seq_file *m = file->private_data;
403
404	kfree(m->private);
405	m->private = NULL;
406	return seq_release(inode, file);
407}
408
409const struct proc_ops fscache_objlist_proc_ops = {
410	.proc_open	= fscache_objlist_open,
411	.proc_read	= seq_read,
412	.proc_lseek	= seq_lseek,
413	.proc_release	= fscache_objlist_release,
414};
415