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f7b422b1 DH |
1 | /* |
2 | * linux/fs/nfs/nfs4namespace.c | |
3 | * | |
4 | * Copyright (C) 2005 Trond Myklebust <Trond.Myklebust@netapp.com> | |
5 | * | |
6 | * NFSv4 namespace | |
7 | */ | |
8 | ||
9 | #include <linux/config.h> | |
10 | ||
11 | #include <linux/dcache.h> | |
12 | #include <linux/mount.h> | |
13 | #include <linux/namei.h> | |
14 | #include <linux/nfs_fs.h> | |
15 | #include <linux/string.h> | |
16 | #include <linux/sunrpc/clnt.h> | |
17 | #include <linux/vfs.h> | |
18 | #include <linux/inet.h> | |
19 | #include "internal.h" | |
20 | ||
21 | #define NFSDBG_FACILITY NFSDBG_VFS | |
22 | ||
23 | /* | |
24 | * Check if fs_root is valid | |
25 | */ | |
26 | static inline char *nfs4_pathname_string(struct nfs4_pathname *pathname, | |
27 | char *buffer, ssize_t buflen) | |
28 | { | |
29 | char *end = buffer + buflen; | |
30 | int n; | |
31 | ||
32 | *--end = '\0'; | |
33 | buflen--; | |
34 | ||
35 | n = pathname->ncomponents; | |
36 | while (--n >= 0) { | |
37 | struct nfs4_string *component = &pathname->components[n]; | |
38 | buflen -= component->len + 1; | |
39 | if (buflen < 0) | |
40 | goto Elong; | |
41 | end -= component->len; | |
42 | memcpy(end, component->data, component->len); | |
43 | *--end = '/'; | |
44 | } | |
45 | return end; | |
46 | Elong: | |
47 | return ERR_PTR(-ENAMETOOLONG); | |
48 | } | |
49 | ||
50 | ||
51 | /** | |
52 | * nfs_follow_referral - set up mountpoint when hitting a referral on moved error | |
53 | * @mnt_parent - mountpoint of parent directory | |
54 | * @dentry - parent directory | |
55 | * @fspath - fs path returned in fs_locations | |
56 | * @mntpath - mount path to new server | |
57 | * @hostname - hostname of new server | |
58 | * @addr - host addr of new server | |
59 | * | |
60 | */ | |
61 | static struct vfsmount *nfs_follow_referral(const struct vfsmount *mnt_parent, | |
62 | const struct dentry *dentry, | |
63 | struct nfs4_fs_locations *locations) | |
64 | { | |
65 | struct vfsmount *mnt = ERR_PTR(-ENOENT); | |
66 | struct nfs_clone_mount mountdata = { | |
67 | .sb = mnt_parent->mnt_sb, | |
68 | .dentry = dentry, | |
69 | .authflavor = NFS_SB(mnt_parent->mnt_sb)->client->cl_auth->au_flavor, | |
70 | }; | |
71 | char *page, *page2; | |
72 | char *path, *fs_path; | |
73 | char *devname; | |
74 | int loc, s; | |
75 | ||
76 | if (locations == NULL || locations->nlocations <= 0) | |
77 | goto out; | |
78 | ||
79 | dprintk("%s: referral at %s/%s\n", __FUNCTION__, | |
80 | dentry->d_parent->d_name.name, dentry->d_name.name); | |
81 | ||
82 | /* Ensure fs path is a prefix of current dentry path */ | |
83 | page = (char *) __get_free_page(GFP_USER); | |
84 | if (page == NULL) | |
85 | goto out; | |
86 | page2 = (char *) __get_free_page(GFP_USER); | |
87 | if (page2 == NULL) | |
88 | goto out; | |
89 | ||
90 | path = nfs4_path(dentry, page, PAGE_SIZE); | |
91 | if (IS_ERR(path)) | |
92 | goto out_free; | |
93 | ||
94 | fs_path = nfs4_pathname_string(&locations->fs_path, page2, PAGE_SIZE); | |
95 | if (IS_ERR(fs_path)) | |
96 | goto out_free; | |
97 | ||
98 | if (strncmp(path, fs_path, strlen(fs_path)) != 0) { | |
99 | dprintk("%s: path %s does not begin with fsroot %s\n", __FUNCTION__, path, fs_path); | |
100 | goto out_free; | |
101 | } | |
102 | ||
103 | devname = nfs_devname(mnt_parent, dentry, page, PAGE_SIZE); | |
104 | if (IS_ERR(devname)) { | |
105 | mnt = (struct vfsmount *)devname; | |
106 | goto out_free; | |
107 | } | |
108 | ||
109 | loc = 0; | |
110 | while (loc < locations->nlocations && IS_ERR(mnt)) { | |
111 | struct nfs4_fs_location *location = &locations->locations[loc]; | |
112 | char *mnt_path; | |
113 | ||
114 | if (location == NULL || location->nservers <= 0 || | |
115 | location->rootpath.ncomponents == 0) { | |
116 | loc++; | |
117 | continue; | |
118 | } | |
119 | ||
120 | mnt_path = nfs4_pathname_string(&location->rootpath, page2, PAGE_SIZE); | |
121 | if (IS_ERR(mnt_path)) { | |
122 | loc++; | |
123 | continue; | |
124 | } | |
125 | mountdata.mnt_path = mnt_path; | |
126 | ||
127 | s = 0; | |
128 | while (s < location->nservers) { | |
129 | struct sockaddr_in addr = {}; | |
130 | ||
131 | if (location->servers[s].len <= 0 || | |
132 | valid_ipaddr4(location->servers[s].data) < 0) { | |
133 | s++; | |
134 | continue; | |
135 | } | |
136 | ||
137 | mountdata.hostname = location->servers[s].data; | |
138 | addr.sin_addr.s_addr = in_aton(mountdata.hostname); | |
139 | addr.sin_family = AF_INET; | |
140 | addr.sin_port = htons(NFS_PORT); | |
141 | mountdata.addr = &addr; | |
142 | ||
143 | mnt = vfs_kern_mount(&nfs_referral_nfs4_fs_type, 0, devname, &mountdata); | |
144 | if (!IS_ERR(mnt)) { | |
145 | break; | |
146 | } | |
147 | s++; | |
148 | } | |
149 | loc++; | |
150 | } | |
151 | ||
152 | out_free: | |
153 | free_page((unsigned long)page); | |
154 | free_page((unsigned long)page2); | |
155 | out: | |
156 | dprintk("%s: done\n", __FUNCTION__); | |
157 | return mnt; | |
158 | } | |
159 | ||
160 | /* | |
161 | * nfs_do_refmount - handle crossing a referral on server | |
162 | * @dentry - dentry of referral | |
163 | * @nd - nameidata info | |
164 | * | |
165 | */ | |
166 | struct vfsmount *nfs_do_refmount(const struct vfsmount *mnt_parent, struct dentry *dentry) | |
167 | { | |
168 | struct vfsmount *mnt = ERR_PTR(-ENOENT); | |
169 | struct dentry *parent; | |
170 | struct nfs4_fs_locations *fs_locations = NULL; | |
171 | struct page *page; | |
172 | int err; | |
173 | ||
174 | /* BUG_ON(IS_ROOT(dentry)); */ | |
175 | dprintk("%s: enter\n", __FUNCTION__); | |
176 | ||
177 | page = alloc_page(GFP_KERNEL); | |
178 | if (page == NULL) | |
179 | goto out; | |
180 | ||
181 | fs_locations = kmalloc(sizeof(struct nfs4_fs_locations), GFP_KERNEL); | |
182 | if (fs_locations == NULL) | |
183 | goto out_free; | |
184 | ||
185 | /* Get locations */ | |
186 | parent = dget_parent(dentry); | |
187 | dprintk("%s: getting locations for %s/%s\n", __FUNCTION__, parent->d_name.name, dentry->d_name.name); | |
188 | err = nfs4_proc_fs_locations(parent->d_inode, dentry, fs_locations, page); | |
189 | dput(parent); | |
190 | if (err != 0 || fs_locations->nlocations <= 0 || | |
191 | fs_locations->fs_path.ncomponents <= 0) | |
192 | goto out_free; | |
193 | ||
194 | mnt = nfs_follow_referral(mnt_parent, dentry, fs_locations); | |
195 | out_free: | |
196 | __free_page(page); | |
197 | kfree(fs_locations); | |
198 | out: | |
199 | dprintk("%s: done\n", __FUNCTION__); | |
200 | return mnt; | |
201 | } |