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 s: "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 fmt: "%08x %s %3d %2lx %4d %3d @%04llx %zx/%zx",
60 rreq->debug_id,
61 netfs_origins[rreq->origin],
62 refcount_read(r: &rreq->ref),
63 rreq->flags,
64 rreq->error,
65 atomic_read(v: &rreq->nr_outstanding),
66 rreq->start, rreq->submitted, rreq->len);
67 seq_putc(m, c: '\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(head: &netfs_io_requests, pos: *_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, head: &netfs_io_requests, ppos: _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);
130

source code of linux/fs/netfs/main.c