Commit | Line | Data |
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6d5ae0de IM |
1 | /* |
2 | * Contains the CIFS DFS referral mounting routines used for handling | |
3 | * traversal via DFS junction point | |
4 | * | |
5 | * Copyright (c) 2007 Igor Mammedov | |
366781c1 | 6 | * Copyright (C) International Business Machines Corp., 2008 |
6d5ae0de | 7 | * Author(s): Igor Mammedov (niallain@gmail.com) |
366781c1 | 8 | * Steve French (sfrench@us.ibm.com) |
6d5ae0de IM |
9 | * This program is free software; you can redistribute it and/or |
10 | * modify it under the terms of the GNU General Public License | |
11 | * as published by the Free Software Foundation; either version | |
12 | * 2 of the License, or (at your option) any later version. | |
13 | */ | |
14 | ||
15 | #include <linux/dcache.h> | |
16 | #include <linux/mount.h> | |
17 | #include <linux/namei.h> | |
18 | #include <linux/vfs.h> | |
19 | #include <linux/fs.h> | |
20 | #include "cifsglob.h" | |
21 | #include "cifsproto.h" | |
22 | #include "cifsfs.h" | |
23 | #include "dns_resolve.h" | |
24 | #include "cifs_debug.h" | |
25 | ||
8d142137 | 26 | static LIST_HEAD(cifs_dfs_automount_list); |
6d5ae0de | 27 | |
78d31a3a IM |
28 | static void cifs_dfs_expire_automounts(struct work_struct *work); |
29 | static DECLARE_DELAYED_WORK(cifs_dfs_automount_task, | |
30 | cifs_dfs_expire_automounts); | |
31 | static int cifs_dfs_mountpoint_expiry_timeout = 500 * HZ; | |
32 | ||
33 | static void cifs_dfs_expire_automounts(struct work_struct *work) | |
34 | { | |
35 | struct list_head *list = &cifs_dfs_automount_list; | |
36 | ||
37 | mark_mounts_for_expiry(list); | |
38 | if (!list_empty(list)) | |
39 | schedule_delayed_work(&cifs_dfs_automount_task, | |
40 | cifs_dfs_mountpoint_expiry_timeout); | |
41 | } | |
6d5ae0de | 42 | |
78d31a3a | 43 | void cifs_dfs_release_automount_timer(void) |
6d5ae0de | 44 | { |
78d31a3a IM |
45 | BUG_ON(!list_empty(&cifs_dfs_automount_list)); |
46 | cancel_delayed_work(&cifs_dfs_automount_task); | |
47 | flush_scheduled_work(); | |
6d5ae0de IM |
48 | } |
49 | ||
50 | /** | |
51 | * cifs_get_share_name - extracts share name from UNC | |
52 | * @node_name: pointer to UNC string | |
53 | * | |
54 | * Extracts sharename form full UNC. | |
55 | * i.e. strips from UNC trailing path that is not part of share | |
56 | * name and fixup missing '\' in the begining of DFS node refferal | |
57 | * if neccessary. | |
58 | * Returns pointer to share name on success or NULL on error. | |
59 | * Caller is responsible for freeing returned string. | |
60 | */ | |
61 | static char *cifs_get_share_name(const char *node_name) | |
62 | { | |
63 | int len; | |
64 | char *UNC; | |
65 | char *pSep; | |
66 | ||
67 | len = strlen(node_name); | |
68 | UNC = kmalloc(len+2 /*for term null and additional \ if it's missed */, | |
69 | GFP_KERNEL); | |
70 | if (!UNC) | |
71 | return NULL; | |
72 | ||
73 | /* get share name and server name */ | |
74 | if (node_name[1] != '\\') { | |
75 | UNC[0] = '\\'; | |
76 | strncpy(UNC+1, node_name, len); | |
77 | len++; | |
78 | UNC[len] = 0; | |
79 | } else { | |
80 | strncpy(UNC, node_name, len); | |
81 | UNC[len] = 0; | |
82 | } | |
83 | ||
84 | /* find server name end */ | |
85 | pSep = memchr(UNC+2, '\\', len-2); | |
86 | if (!pSep) { | |
87 | cERROR(1, ("%s: no server name end in node name: %s", | |
55f78e17 | 88 | __func__, node_name)); |
6d5ae0de IM |
89 | kfree(UNC); |
90 | return NULL; | |
91 | } | |
92 | ||
93 | /* find sharename end */ | |
94 | pSep++; | |
95 | pSep = memchr(UNC+(pSep-UNC), '\\', len-(pSep-UNC)); | |
bf62fd88 IM |
96 | if (pSep) { |
97 | /* trim path up to sharename end | |
98 | * now we have share name in UNC */ | |
99 | *pSep = 0; | |
6d5ae0de | 100 | } |
6d5ae0de IM |
101 | |
102 | return UNC; | |
103 | } | |
104 | ||
105 | ||
106 | /** | |
107 | * compose_mount_options - creates mount options for refferral | |
108 | * @sb_mountdata: parent/root DFS mount options (template) | |
109 | * @ref_unc: refferral server UNC | |
110 | * @devname: pointer for saving device name | |
111 | * | |
112 | * creates mount options for submount based on template options sb_mountdata | |
113 | * and replacing unc,ip,prefixpath options with ones we've got form ref_unc. | |
114 | * | |
115 | * Returns: pointer to new mount options or ERR_PTR. | |
116 | * Caller is responcible for freeing retunrned value if it is not error. | |
117 | */ | |
366781c1 SF |
118 | static char *compose_mount_options(const char *sb_mountdata, |
119 | const char *ref_unc, | |
120 | char **devname) | |
6d5ae0de IM |
121 | { |
122 | int rc; | |
123 | char *mountdata; | |
124 | int md_len; | |
125 | char *tkn_e; | |
126 | char *srvIP = NULL; | |
127 | char sep = ','; | |
128 | int off, noff; | |
129 | ||
130 | if (sb_mountdata == NULL) | |
131 | return ERR_PTR(-EINVAL); | |
132 | ||
133 | *devname = cifs_get_share_name(ref_unc); | |
134 | rc = dns_resolve_server_name_to_ip(*devname, &srvIP); | |
135 | if (rc != 0) { | |
136 | cERROR(1, ("%s: Failed to resolve server part of %s to IP", | |
55f78e17 | 137 | __func__, *devname)); |
6d5ae0de IM |
138 | mountdata = ERR_PTR(rc); |
139 | goto compose_mount_options_out; | |
140 | } | |
141 | md_len = strlen(sb_mountdata) + strlen(srvIP) + strlen(ref_unc) + 3; | |
142 | mountdata = kzalloc(md_len+1, GFP_KERNEL); | |
143 | if (mountdata == NULL) { | |
144 | mountdata = ERR_PTR(-ENOMEM); | |
145 | goto compose_mount_options_out; | |
146 | } | |
147 | ||
148 | /* copy all options except of unc,ip,prefixpath */ | |
149 | off = 0; | |
150 | if (strncmp(sb_mountdata, "sep=", 4) == 0) { | |
151 | sep = sb_mountdata[4]; | |
152 | strncpy(mountdata, sb_mountdata, 5); | |
153 | off += 5; | |
154 | } | |
155 | while ((tkn_e = strchr(sb_mountdata+off, sep))) { | |
156 | noff = (tkn_e - (sb_mountdata+off)) + 1; | |
157 | if (strnicmp(sb_mountdata+off, "unc=", 4) == 0) { | |
158 | off += noff; | |
159 | continue; | |
160 | } | |
161 | if (strnicmp(sb_mountdata+off, "ip=", 3) == 0) { | |
162 | off += noff; | |
163 | continue; | |
164 | } | |
165 | if (strnicmp(sb_mountdata+off, "prefixpath=", 3) == 0) { | |
166 | off += noff; | |
167 | continue; | |
168 | } | |
169 | strncat(mountdata, sb_mountdata+off, noff); | |
170 | off += noff; | |
171 | } | |
172 | strcat(mountdata, sb_mountdata+off); | |
173 | mountdata[md_len] = '\0'; | |
174 | ||
175 | /* copy new IP and ref share name */ | |
176 | strcat(mountdata, ",ip="); | |
177 | strcat(mountdata, srvIP); | |
178 | strcat(mountdata, ",unc="); | |
179 | strcat(mountdata, *devname); | |
180 | ||
181 | /* find & copy prefixpath */ | |
182 | tkn_e = strchr(ref_unc+2, '\\'); | |
183 | if (tkn_e) { | |
184 | tkn_e = strchr(tkn_e+1, '\\'); | |
185 | if (tkn_e) { | |
186 | strcat(mountdata, ",prefixpath="); | |
bf62fd88 | 187 | strcat(mountdata, tkn_e+1); |
6d5ae0de IM |
188 | } |
189 | } | |
190 | ||
55f78e17 HH |
191 | /*cFYI(1,("%s: parent mountdata: %s", __func__,sb_mountdata));*/ |
192 | /*cFYI(1, ("%s: submount mountdata: %s", __func__, mountdata ));*/ | |
6d5ae0de IM |
193 | |
194 | compose_mount_options_out: | |
195 | kfree(srvIP); | |
196 | return mountdata; | |
197 | } | |
198 | ||
199 | ||
366781c1 | 200 | static struct vfsmount *cifs_dfs_do_refmount(const struct vfsmount *mnt_parent, |
6d5ae0de IM |
201 | struct dentry *dentry, char *ref_unc) |
202 | { | |
203 | struct cifs_sb_info *cifs_sb; | |
204 | struct vfsmount *mnt; | |
205 | char *mountdata; | |
366781c1 | 206 | char *devname = NULL; |
6d5ae0de IM |
207 | |
208 | cifs_sb = CIFS_SB(dentry->d_inode->i_sb); | |
209 | mountdata = compose_mount_options(cifs_sb->mountdata, | |
210 | ref_unc, &devname); | |
211 | ||
212 | if (IS_ERR(mountdata)) | |
213 | return (struct vfsmount *)mountdata; | |
214 | ||
215 | mnt = vfs_kern_mount(&cifs_fs_type, 0, devname, mountdata); | |
216 | kfree(mountdata); | |
217 | kfree(devname); | |
218 | return mnt; | |
219 | ||
220 | } | |
221 | ||
6d5ae0de IM |
222 | static int add_mount_helper(struct vfsmount *newmnt, struct nameidata *nd, |
223 | struct list_head *mntlist) | |
224 | { | |
225 | /* stolen from afs code */ | |
226 | int err; | |
227 | ||
228 | mntget(newmnt); | |
4ac91378 | 229 | err = do_add_mount(newmnt, nd, nd->path.mnt->mnt_flags, mntlist); |
6d5ae0de IM |
230 | switch (err) { |
231 | case 0: | |
78d31a3a | 232 | path_put(&nd->path); |
4ac91378 JB |
233 | nd->path.mnt = newmnt; |
234 | nd->path.dentry = dget(newmnt->mnt_root); | |
78d31a3a IM |
235 | schedule_delayed_work(&cifs_dfs_automount_task, |
236 | cifs_dfs_mountpoint_expiry_timeout); | |
6d5ae0de IM |
237 | break; |
238 | case -EBUSY: | |
239 | /* someone else made a mount here whilst we were busy */ | |
4ac91378 JB |
240 | while (d_mountpoint(nd->path.dentry) && |
241 | follow_down(&nd->path.mnt, &nd->path.dentry)) | |
6d5ae0de IM |
242 | ; |
243 | err = 0; | |
244 | default: | |
245 | mntput(newmnt); | |
246 | break; | |
247 | } | |
248 | return err; | |
249 | } | |
250 | ||
366781c1 | 251 | static void dump_referral(const struct dfs_info3_param *ref) |
6d5ae0de IM |
252 | { |
253 | cFYI(1, ("DFS: ref path: %s", ref->path_name)); | |
254 | cFYI(1, ("DFS: node path: %s", ref->node_name)); | |
255 | cFYI(1, ("DFS: fl: %hd, srv_type: %hd", ref->flags, ref->server_type)); | |
256 | cFYI(1, ("DFS: ref_flags: %hd, path_consumed: %hd", ref->ref_flag, | |
8aad018b | 257 | ref->path_consumed)); |
6d5ae0de IM |
258 | } |
259 | ||
260 | ||
261 | static void* | |
262 | cifs_dfs_follow_mountpoint(struct dentry *dentry, struct nameidata *nd) | |
263 | { | |
264 | struct dfs_info3_param *referrals = NULL; | |
265 | unsigned int num_referrals = 0; | |
266 | struct cifs_sb_info *cifs_sb; | |
267 | struct cifsSesInfo *ses; | |
268 | char *full_path = NULL; | |
269 | int xid, i; | |
270 | int rc = 0; | |
271 | struct vfsmount *mnt = ERR_PTR(-ENOENT); | |
272 | ||
55f78e17 | 273 | cFYI(1, ("in %s", __func__)); |
6d5ae0de IM |
274 | BUG_ON(IS_ROOT(dentry)); |
275 | ||
276 | xid = GetXid(); | |
277 | ||
4ac91378 JB |
278 | dput(nd->path.dentry); |
279 | nd->path.dentry = dget(dentry); | |
6d5ae0de IM |
280 | |
281 | cifs_sb = CIFS_SB(dentry->d_inode->i_sb); | |
282 | ses = cifs_sb->tcon->ses; | |
283 | ||
284 | if (!ses) { | |
285 | rc = -EINVAL; | |
286 | goto out_err; | |
287 | } | |
288 | ||
de2db8d7 | 289 | full_path = build_path_from_dentry(dentry); |
6d5ae0de IM |
290 | if (full_path == NULL) { |
291 | rc = -ENOMEM; | |
292 | goto out_err; | |
293 | } | |
294 | ||
295 | rc = get_dfs_path(xid, ses , full_path, cifs_sb->local_nls, | |
296 | &num_referrals, &referrals, | |
297 | cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR); | |
298 | ||
299 | for (i = 0; i < num_referrals; i++) { | |
300 | dump_referral(referrals+i); | |
301 | /* connect to a storage node */ | |
302 | if (referrals[i].flags & DFSREF_STORAGE_SERVER) { | |
303 | int len; | |
304 | len = strlen(referrals[i].node_name); | |
305 | if (len < 2) { | |
306 | cERROR(1, ("%s: Net Address path too short: %s", | |
55f78e17 | 307 | __func__, referrals[i].node_name)); |
6d5ae0de IM |
308 | rc = -EINVAL; |
309 | goto out_err; | |
310 | } | |
4ac91378 JB |
311 | mnt = cifs_dfs_do_refmount(nd->path.mnt, |
312 | nd->path.dentry, | |
6d5ae0de IM |
313 | referrals[i].node_name); |
314 | cFYI(1, ("%s: cifs_dfs_do_refmount:%s , mnt:%p", | |
55f78e17 | 315 | __func__, |
6d5ae0de IM |
316 | referrals[i].node_name, mnt)); |
317 | ||
318 | /* complete mount procedure if we accured submount */ | |
319 | if (!IS_ERR(mnt)) | |
320 | break; | |
321 | } | |
322 | } | |
323 | ||
324 | /* we need it cause for() above could exit without valid submount */ | |
325 | rc = PTR_ERR(mnt); | |
326 | if (IS_ERR(mnt)) | |
327 | goto out_err; | |
328 | ||
4ac91378 | 329 | nd->path.mnt->mnt_flags |= MNT_SHRINKABLE; |
6d5ae0de IM |
330 | rc = add_mount_helper(mnt, nd, &cifs_dfs_automount_list); |
331 | ||
332 | out: | |
333 | FreeXid(xid); | |
334 | free_dfs_info_array(referrals, num_referrals); | |
335 | kfree(full_path); | |
55f78e17 | 336 | cFYI(1, ("leaving %s" , __func__)); |
6d5ae0de IM |
337 | return ERR_PTR(rc); |
338 | out_err: | |
1d957f9b | 339 | path_put(&nd->path); |
6d5ae0de IM |
340 | goto out; |
341 | } | |
342 | ||
343 | struct inode_operations cifs_dfs_referral_inode_operations = { | |
344 | .follow_link = cifs_dfs_follow_mountpoint, | |
345 | }; | |
346 |