1 // SPDX-License-Identifier: GPL-2.0
2
3 #include <linux/debugfs.h>
4
5 #include "nfsd.h"
6
7 static struct dentry *nfsd_top_dir __read_mostly;
8
9 /*
10 * /sys/kernel/debug/nfsd/disable-splice-read
11 *
12 * Contents:
13 * %0: NFS READ is allowed to use page splicing
14 * %1: NFS READ uses only iov iter read
15 *
16 * The default value of this setting is zero (page splicing is
17 * allowed). This setting takes immediate effect for all NFS
18 * versions, all exports, and in all NFSD net namespaces.
19 */
20
nfsd_dsr_get(void * data,u64 * val)21 static int nfsd_dsr_get(void *data, u64 *val)
22 {
23 *val = nfsd_disable_splice_read ? 1 : 0;
24 return 0;
25 }
26
nfsd_dsr_set(void * data,u64 val)27 static int nfsd_dsr_set(void *data, u64 val)
28 {
29 nfsd_disable_splice_read = (val > 0);
30 if (!nfsd_disable_splice_read) {
31 /*
32 * Must use buffered I/O if splice_read is enabled.
33 */
34 nfsd_io_cache_read = NFSD_IO_BUFFERED;
35 }
36 return 0;
37 }
38
39 DEFINE_DEBUGFS_ATTRIBUTE(nfsd_dsr_fops, nfsd_dsr_get, nfsd_dsr_set, "%llu\n");
40
41 /*
42 * /sys/kernel/debug/nfsd/io_cache_read
43 *
44 * Contents:
45 * %0: NFS READ will use buffered IO
46 * %1: NFS READ will use dontcache (buffered IO w/ dropbehind)
47 * %2: NFS READ will use direct IO
48 *
49 * This setting takes immediate effect for all NFS versions,
50 * all exports, and in all NFSD net namespaces.
51 */
52
nfsd_io_cache_read_get(void * data,u64 * val)53 static int nfsd_io_cache_read_get(void *data, u64 *val)
54 {
55 *val = nfsd_io_cache_read;
56 return 0;
57 }
58
nfsd_io_cache_read_set(void * data,u64 val)59 static int nfsd_io_cache_read_set(void *data, u64 val)
60 {
61 int ret = 0;
62
63 switch (val) {
64 case NFSD_IO_BUFFERED:
65 nfsd_io_cache_read = NFSD_IO_BUFFERED;
66 break;
67 case NFSD_IO_DONTCACHE:
68 case NFSD_IO_DIRECT:
69 /*
70 * Must disable splice_read when enabling
71 * NFSD_IO_DONTCACHE.
72 */
73 nfsd_disable_splice_read = true;
74 nfsd_io_cache_read = val;
75 break;
76 default:
77 ret = -EINVAL;
78 break;
79 }
80
81 return ret;
82 }
83
84 DEFINE_DEBUGFS_ATTRIBUTE(nfsd_io_cache_read_fops, nfsd_io_cache_read_get,
85 nfsd_io_cache_read_set, "%llu\n");
86
87 /*
88 * /sys/kernel/debug/nfsd/io_cache_write
89 *
90 * Contents:
91 * %0: NFS WRITE will use buffered IO
92 * %1: NFS WRITE will use dontcache (buffered IO w/ dropbehind)
93 *
94 * This setting takes immediate effect for all NFS versions,
95 * all exports, and in all NFSD net namespaces.
96 */
97
nfsd_io_cache_write_get(void * data,u64 * val)98 static int nfsd_io_cache_write_get(void *data, u64 *val)
99 {
100 *val = nfsd_io_cache_write;
101 return 0;
102 }
103
nfsd_io_cache_write_set(void * data,u64 val)104 static int nfsd_io_cache_write_set(void *data, u64 val)
105 {
106 int ret = 0;
107
108 switch (val) {
109 case NFSD_IO_BUFFERED:
110 case NFSD_IO_DONTCACHE:
111 case NFSD_IO_DIRECT:
112 nfsd_io_cache_write = val;
113 break;
114 default:
115 ret = -EINVAL;
116 break;
117 }
118
119 return ret;
120 }
121
122 DEFINE_DEBUGFS_ATTRIBUTE(nfsd_io_cache_write_fops, nfsd_io_cache_write_get,
123 nfsd_io_cache_write_set, "%llu\n");
124
nfsd_debugfs_exit(void)125 void nfsd_debugfs_exit(void)
126 {
127 debugfs_remove_recursive(nfsd_top_dir);
128 nfsd_top_dir = NULL;
129 }
130
nfsd_debugfs_init(void)131 void nfsd_debugfs_init(void)
132 {
133 nfsd_top_dir = debugfs_create_dir("nfsd", NULL);
134
135 debugfs_create_file("disable-splice-read", S_IWUSR | S_IRUGO,
136 nfsd_top_dir, NULL, &nfsd_dsr_fops);
137
138 debugfs_create_file("io_cache_read", 0644, nfsd_top_dir, NULL,
139 &nfsd_io_cache_read_fops);
140
141 debugfs_create_file("io_cache_write", 0644, nfsd_top_dir, NULL,
142 &nfsd_io_cache_write_fops);
143 }
144