1// SPDX-License-Identifier: GPL-2.0-or-later
  2/* Miscellaneous bits for the netfs support library.
  3 *
  4 * Copyright (C) 2022 Red Hat, Inc. All Rights Reserved.
  5 * Written by David Howells (dhowells@redhat.com)
  6 */
  7
  8#include <linux/module.h>
  9#include <linux/export.h>
 10#include <linux/proc_fs.h>
 11#include <linux/seq_file.h>
 12#include "internal.h"
 13#define CREATE_TRACE_POINTS
 14#include <trace/events/netfs.h>
 15
 16MODULE_DESCRIPTION("Network fs support");
 17MODULE_AUTHOR("Red Hat, Inc.");
 18MODULE_LICENSE("GPL");
 19
 20EXPORT_TRACEPOINT_SYMBOL(netfs_sreq);
 21
 22unsigned netfs_debug;
 23module_param_named(debug, netfs_debug, uint, S_IWUSR | S_IRUGO);
 24MODULE_PARM_DESC(netfs_debug, "Netfs support debugging mask");
 25
 26#ifdef CONFIG_PROC_FS
 27LIST_HEAD(netfs_io_requests);
 28DEFINE_SPINLOCK(netfs_proc_lock);
 29
 30static const char *netfs_origins[nr__netfs_io_origin] = {
 31	[NETFS_READAHEAD]		= "RA",
 32	[NETFS_READPAGE]		= "RP",
 33	[NETFS_READ_FOR_WRITE]		= "RW",
 34	[NETFS_WRITEBACK]		= "WB",
 35	[NETFS_WRITETHROUGH]		= "WT",
 36	[NETFS_LAUNDER_WRITE]		= "LW",
 37	[NETFS_UNBUFFERED_WRITE]	= "UW",
 38	[NETFS_DIO_READ]		= "DR",
 39	[NETFS_DIO_WRITE]		= "DW",
 40};
 41
 42/*
 43 * Generate a list of I/O requests in /proc/fs/netfs/requests
 44 */
 45static int netfs_requests_seq_show(struct seq_file *m, void *v)
 46{
 47	struct netfs_io_request *rreq;
 48
 49	if (v == &netfs_io_requests) {
 50		seq_puts(m,
 51			 "REQUEST  OR REF FL ERR  OPS COVERAGE\n"
 52			 "======== == === == ==== === =========\n"
 53			 );
 54		return 0;
 55	}
 56
 57	rreq = list_entry(v, struct netfs_io_request, proc_link);
 58	seq_printf(m,
 59		   "%08x %s %3d %2lx %4d %3d @%04llx %zx/%zx",
 60		   rreq->debug_id,
 61		   netfs_origins[rreq->origin],
 62		   refcount_read(&rreq->ref),
 63		   rreq->flags,
 64		   rreq->error,
 65		   atomic_read(&rreq->nr_outstanding),
 66		   rreq->start, rreq->submitted, rreq->len);
 67	seq_putc(m, '\n');
 68	return 0;
 69}
 70
 71static void *netfs_requests_seq_start(struct seq_file *m, loff_t *_pos)
 72	__acquires(rcu)
 73{
 74	rcu_read_lock();
 75	return seq_list_start_head(&netfs_io_requests, *_pos);
 76}
 77
 78static void *netfs_requests_seq_next(struct seq_file *m, void *v, loff_t *_pos)
 79{
 80	return seq_list_next(v, &netfs_io_requests, _pos);
 81}
 82
 83static void netfs_requests_seq_stop(struct seq_file *m, void *v)
 84	__releases(rcu)
 85{
 86	rcu_read_unlock();
 87}
 88
 89static const struct seq_operations netfs_requests_seq_ops = {
 90	.start  = netfs_requests_seq_start,
 91	.next   = netfs_requests_seq_next,
 92	.stop   = netfs_requests_seq_stop,
 93	.show   = netfs_requests_seq_show,
 94};
 95#endif /* CONFIG_PROC_FS */
 96
 97static int __init netfs_init(void)
 98{
 99	int ret = -ENOMEM;
100
101	if (!proc_mkdir("fs/netfs", NULL))
102		goto error;
103	if (!proc_create_seq("fs/netfs/requests", S_IFREG | 0444, NULL,
104			     &netfs_requests_seq_ops))
105		goto error_proc;
106#ifdef CONFIG_FSCACHE_STATS
107	if (!proc_create_single("fs/netfs/stats", S_IFREG | 0444, NULL,
108				netfs_stats_show))
109		goto error_proc;
110#endif
111
112	ret = fscache_init();
113	if (ret < 0)
114		goto error_proc;
115	return 0;
116
117error_proc:
118	remove_proc_entry("fs/netfs", NULL);
119error:
120	return ret;
121}
122fs_initcall(netfs_init);
123
124static void __exit netfs_exit(void)
125{
126	fscache_exit();
127	remove_proc_entry("fs/netfs", NULL);
128}
129module_exit(netfs_exit);