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Commit | Line | Data |
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1107ba88 AZ |
1 | /* |
2 | * xenfs.c - a filesystem for passing info between the a domain and | |
3 | * the hypervisor. | |
4 | * | |
5 | * 2008-10-07 Alex Zeffertt Replaced /proc/xen/xenbus with xenfs filesystem | |
6 | * and /proc/xen compatibility mount point. | |
7 | * Turned xenfs into a loadable module. | |
8 | */ | |
9 | ||
10 | #include <linux/kernel.h> | |
11 | #include <linux/errno.h> | |
12 | #include <linux/module.h> | |
13 | #include <linux/fs.h> | |
14 | #include <linux/magic.h> | |
24a89b5b JF |
15 | #include <linux/mm.h> |
16 | #include <linux/backing-dev.h> | |
1107ba88 | 17 | |
1ccbf534 JF |
18 | #include <xen/xen.h> |
19 | ||
1107ba88 AZ |
20 | #include "xenfs.h" |
21 | ||
22 | #include <asm/xen/hypervisor.h> | |
23 | ||
24 | MODULE_DESCRIPTION("Xen filesystem"); | |
25 | MODULE_LICENSE("GPL"); | |
26 | ||
24a89b5b JF |
27 | static int xenfs_set_page_dirty(struct page *page) |
28 | { | |
35f8c1c3 | 29 | return !TestSetPageDirty(page); |
24a89b5b JF |
30 | } |
31 | ||
32 | static const struct address_space_operations xenfs_aops = { | |
33 | .set_page_dirty = xenfs_set_page_dirty, | |
34 | }; | |
35 | ||
36 | static struct backing_dev_info xenfs_backing_dev_info = { | |
37 | .ra_pages = 0, /* No readahead */ | |
38 | .capabilities = BDI_CAP_NO_ACCT_AND_WRITEBACK, | |
39 | }; | |
40 | ||
655d406a IC |
41 | static struct inode *xenfs_make_inode(struct super_block *sb, int mode) |
42 | { | |
43 | struct inode *ret = new_inode(sb); | |
44 | ||
45 | if (ret) { | |
46 | ret->i_mode = mode; | |
24a89b5b JF |
47 | ret->i_mapping->a_ops = &xenfs_aops; |
48 | ret->i_mapping->backing_dev_info = &xenfs_backing_dev_info; | |
655d406a IC |
49 | ret->i_uid = ret->i_gid = 0; |
50 | ret->i_blocks = 0; | |
51 | ret->i_atime = ret->i_mtime = ret->i_ctime = CURRENT_TIME; | |
52 | } | |
53 | return ret; | |
54 | } | |
55 | ||
56 | static struct dentry *xenfs_create_file(struct super_block *sb, | |
57 | struct dentry *parent, | |
58 | const char *name, | |
59 | const struct file_operations *fops, | |
60 | void *data, | |
61 | int mode) | |
62 | { | |
63 | struct dentry *dentry; | |
64 | struct inode *inode; | |
65 | ||
66 | dentry = d_alloc_name(parent, name); | |
67 | if (!dentry) | |
68 | return NULL; | |
69 | ||
70 | inode = xenfs_make_inode(sb, S_IFREG | mode); | |
71 | if (!inode) { | |
72 | dput(dentry); | |
73 | return NULL; | |
74 | } | |
75 | ||
76 | inode->i_fop = fops; | |
77 | inode->i_private = data; | |
78 | ||
79 | d_add(dentry, inode); | |
80 | return dentry; | |
81 | } | |
82 | ||
818fd206 JF |
83 | static ssize_t capabilities_read(struct file *file, char __user *buf, |
84 | size_t size, loff_t *off) | |
85 | { | |
86 | char *tmp = ""; | |
87 | ||
88 | if (xen_initial_domain()) | |
89 | tmp = "control_d\n"; | |
90 | ||
91 | return simple_read_from_buffer(buf, size, off, tmp, strlen(tmp)); | |
92 | } | |
93 | ||
94 | static const struct file_operations capabilities_file_ops = { | |
95 | .read = capabilities_read, | |
6038f373 | 96 | .llseek = default_llseek, |
818fd206 JF |
97 | }; |
98 | ||
1107ba88 AZ |
99 | static int xenfs_fill_super(struct super_block *sb, void *data, int silent) |
100 | { | |
101 | static struct tree_descr xenfs_files[] = { | |
818fd206 JF |
102 | [1] = {}, |
103 | { "xenbus", &xenbus_file_ops, S_IRUSR|S_IWUSR }, | |
104 | { "capabilities", &capabilities_file_ops, S_IRUGO }, | |
9387377e | 105 | { "privcmd", &privcmd_file_ops, S_IRUSR|S_IWUSR }, |
1107ba88 AZ |
106 | {""}, |
107 | }; | |
655d406a | 108 | int rc; |
1107ba88 | 109 | |
655d406a IC |
110 | rc = simple_fill_super(sb, XENFS_SUPER_MAGIC, xenfs_files); |
111 | if (rc < 0) | |
112 | return rc; | |
113 | ||
114 | if (xen_initial_domain()) { | |
115 | xenfs_create_file(sb, sb->s_root, "xsd_kva", | |
116 | &xsd_kva_file_ops, NULL, S_IRUSR|S_IWUSR); | |
117 | xenfs_create_file(sb, sb->s_root, "xsd_port", | |
118 | &xsd_port_file_ops, NULL, S_IRUSR|S_IWUSR); | |
119 | } | |
1107ba88 | 120 | |
655d406a | 121 | return rc; |
1107ba88 AZ |
122 | } |
123 | ||
fc14f2fe | 124 | static int xenfs_mount(struct file_system_type *fs_type, |
1107ba88 | 125 | int flags, const char *dev_name, |
fc14f2fe | 126 | void *data) |
1107ba88 | 127 | { |
fc14f2fe | 128 | return mount_single(fs_type, flags, data, xenfs_fill_super); |
1107ba88 AZ |
129 | } |
130 | ||
131 | static struct file_system_type xenfs_type = { | |
132 | .owner = THIS_MODULE, | |
133 | .name = "xenfs", | |
fc14f2fe | 134 | .mount = xenfs_mount, |
1107ba88 AZ |
135 | .kill_sb = kill_litter_super, |
136 | }; | |
137 | ||
138 | static int __init xenfs_init(void) | |
139 | { | |
24a89b5b JF |
140 | int err; |
141 | if (!xen_domain()) { | |
142 | printk(KERN_INFO "xenfs: not registering filesystem on non-xen platform\n"); | |
143 | return 0; | |
144 | } | |
1107ba88 | 145 | |
24a89b5b JF |
146 | err = register_filesystem(&xenfs_type); |
147 | if (err) { | |
148 | printk(KERN_ERR "xenfs: Unable to register filesystem!\n"); | |
149 | goto out; | |
150 | } | |
151 | ||
152 | err = bdi_init(&xenfs_backing_dev_info); | |
153 | if (err) | |
154 | unregister_filesystem(&xenfs_type); | |
155 | ||
156 | out: | |
1107ba88 | 157 | |
24a89b5b | 158 | return err; |
1107ba88 AZ |
159 | } |
160 | ||
161 | static void __exit xenfs_exit(void) | |
162 | { | |
43df95c4 | 163 | if (xen_domain()) |
1107ba88 AZ |
164 | unregister_filesystem(&xenfs_type); |
165 | } | |
166 | ||
167 | module_init(xenfs_init); | |
168 | module_exit(xenfs_exit); | |
169 |