2 * Contains the CIFS DFS referral mounting routines used for handling
3 * traversal via DFS junction point
5 * Copyright (c) 2007 Igor Mammedov
6 * Copyright (C) International Business Machines Corp., 2008
7 * Author(s): Igor Mammedov (niallain@gmail.com)
8 * Steve French (sfrench@us.ibm.com)
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.
15 #include <linux/dcache.h>
16 #include <linux/mount.h>
17 #include <linux/namei.h>
18 #include <linux/vfs.h>
21 #include "cifsproto.h"
23 #include "dns_resolve.h"
24 #include "cifs_debug.h"
26 static LIST_HEAD(cifs_dfs_automount_list
);
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
;
33 static void cifs_dfs_expire_automounts(struct work_struct
*work
)
35 struct list_head
*list
= &cifs_dfs_automount_list
;
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
);
43 void cifs_dfs_release_automount_timer(void)
45 BUG_ON(!list_empty(&cifs_dfs_automount_list
));
46 cancel_delayed_work(&cifs_dfs_automount_task
);
47 flush_scheduled_work();
51 * cifs_get_share_name - extracts share name from UNC
52 * @node_name: pointer to UNC string
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
58 * Returns pointer to share name on success or NULL on error.
59 * Caller is responsible for freeing returned string.
61 static char *cifs_get_share_name(const char *node_name
)
67 len
= strlen(node_name
);
68 UNC
= kmalloc(len
+2 /*for term null and additional \ if it's missed */,
73 /* get share name and server name */
74 if (node_name
[1] != '\\') {
76 strncpy(UNC
+1, node_name
, len
);
80 strncpy(UNC
, node_name
, len
);
84 /* find server name end */
85 pSep
= memchr(UNC
+2, '\\', len
-2);
87 cERROR(1, ("%s: no server name end in node name: %s",
88 __func__
, node_name
));
93 /* find sharename end */
95 pSep
= memchr(UNC
+(pSep
-UNC
), '\\', len
-(pSep
-UNC
));
97 /* trim path up to sharename end
98 * now we have share name in UNC */
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
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.
115 * Returns: pointer to new mount options or ERR_PTR.
116 * Caller is responcible for freeing retunrned value if it is not error.
118 static char *compose_mount_options(const char *sb_mountdata
,
130 if (sb_mountdata
== NULL
)
131 return ERR_PTR(-EINVAL
);
133 *devname
= cifs_get_share_name(ref_unc
);
134 rc
= dns_resolve_server_name_to_ip(*devname
, &srvIP
);
136 cERROR(1, ("%s: Failed to resolve server part of %s to IP",
137 __func__
, *devname
));
138 mountdata
= ERR_PTR(rc
);
139 goto compose_mount_options_out
;
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
;
148 /* copy all options except of unc,ip,prefixpath */
150 if (strncmp(sb_mountdata
, "sep=", 4) == 0) {
151 sep
= sb_mountdata
[4];
152 strncpy(mountdata
, sb_mountdata
, 5);
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) {
161 if (strnicmp(sb_mountdata
+off
, "ip=", 3) == 0) {
165 if (strnicmp(sb_mountdata
+off
, "prefixpath=", 3) == 0) {
169 strncat(mountdata
, sb_mountdata
+off
, noff
);
172 strcat(mountdata
, sb_mountdata
+off
);
173 mountdata
[md_len
] = '\0';
175 /* copy new IP and ref share name */
176 strcat(mountdata
, ",ip=");
177 strcat(mountdata
, srvIP
);
178 strcat(mountdata
, ",unc=");
179 strcat(mountdata
, *devname
);
181 /* find & copy prefixpath */
182 tkn_e
= strchr(ref_unc
+2, '\\');
184 tkn_e
= strchr(tkn_e
+1, '\\');
186 strcat(mountdata
, ",prefixpath=");
187 strcat(mountdata
, tkn_e
+1);
191 /*cFYI(1,("%s: parent mountdata: %s", __func__,sb_mountdata));*/
192 /*cFYI(1, ("%s: submount mountdata: %s", __func__, mountdata ));*/
194 compose_mount_options_out
:
200 static struct vfsmount
*cifs_dfs_do_refmount(const struct vfsmount
*mnt_parent
,
201 struct dentry
*dentry
, char *ref_unc
)
203 struct cifs_sb_info
*cifs_sb
;
204 struct vfsmount
*mnt
;
206 char *devname
= NULL
;
208 cifs_sb
= CIFS_SB(dentry
->d_inode
->i_sb
);
209 mountdata
= compose_mount_options(cifs_sb
->mountdata
,
212 if (IS_ERR(mountdata
))
213 return (struct vfsmount
*)mountdata
;
215 mnt
= vfs_kern_mount(&cifs_fs_type
, 0, devname
, mountdata
);
222 static char *build_full_dfs_path_from_dentry(struct dentry
*dentry
)
224 char *full_path
= NULL
;
228 struct cifs_sb_info
*cifs_sb
;
230 if (dentry
->d_inode
== NULL
)
233 cifs_sb
= CIFS_SB(dentry
->d_inode
->i_sb
);
235 if (cifs_sb
->tcon
== NULL
)
238 search_path
= build_path_from_dentry(dentry
);
239 if (search_path
== NULL
)
242 if (cifs_sb
->tcon
->Flags
& SMB_SHARE_IS_IN_DFS
) {
244 /* we should use full path name for correct working with DFS */
245 l_max_len
= strnlen(cifs_sb
->tcon
->treeName
, MAX_TREE_SIZE
+1) +
246 strnlen(search_path
, MAX_PATHCONF
) + 1;
247 tmp_path
= kmalloc(l_max_len
, GFP_KERNEL
);
248 if (tmp_path
== NULL
) {
252 strncpy(tmp_path
, cifs_sb
->tcon
->treeName
, l_max_len
);
253 tmp_path
[l_max_len
-1] = 0;
254 if (cifs_sb
->mnt_cifs_flags
& CIFS_MOUNT_POSIX_PATHS
)
255 for (i
= 0; i
< l_max_len
; i
++) {
256 if (tmp_path
[i
] == '\\')
259 strncat(tmp_path
, search_path
, l_max_len
- strlen(tmp_path
));
261 full_path
= tmp_path
;
264 full_path
= search_path
;
269 static int add_mount_helper(struct vfsmount
*newmnt
, struct nameidata
*nd
,
270 struct list_head
*mntlist
)
272 /* stolen from afs code */
276 err
= do_add_mount(newmnt
, nd
, nd
->path
.mnt
->mnt_flags
, mntlist
);
280 nd
->path
.mnt
= newmnt
;
281 nd
->path
.dentry
= dget(newmnt
->mnt_root
);
282 schedule_delayed_work(&cifs_dfs_automount_task
,
283 cifs_dfs_mountpoint_expiry_timeout
);
286 /* someone else made a mount here whilst we were busy */
287 while (d_mountpoint(nd
->path
.dentry
) &&
288 follow_down(&nd
->path
.mnt
, &nd
->path
.dentry
))
298 static void dump_referral(const struct dfs_info3_param
*ref
)
300 cFYI(1, ("DFS: ref path: %s", ref
->path_name
));
301 cFYI(1, ("DFS: node path: %s", ref
->node_name
));
302 cFYI(1, ("DFS: fl: %hd, srv_type: %hd", ref
->flags
, ref
->server_type
));
303 cFYI(1, ("DFS: ref_flags: %hd, path_consumed: %hd", ref
->ref_flag
,
304 ref
->path_consumed
));
309 cifs_dfs_follow_mountpoint(struct dentry
*dentry
, struct nameidata
*nd
)
311 struct dfs_info3_param
*referrals
= NULL
;
312 unsigned int num_referrals
= 0;
313 struct cifs_sb_info
*cifs_sb
;
314 struct cifsSesInfo
*ses
;
315 char *full_path
= NULL
;
318 struct vfsmount
*mnt
= ERR_PTR(-ENOENT
);
320 cFYI(1, ("in %s", __func__
));
321 BUG_ON(IS_ROOT(dentry
));
325 dput(nd
->path
.dentry
);
326 nd
->path
.dentry
= dget(dentry
);
328 cifs_sb
= CIFS_SB(dentry
->d_inode
->i_sb
);
329 ses
= cifs_sb
->tcon
->ses
;
336 full_path
= build_full_dfs_path_from_dentry(dentry
);
337 if (full_path
== NULL
) {
342 rc
= get_dfs_path(xid
, ses
, full_path
, cifs_sb
->local_nls
,
343 &num_referrals
, &referrals
,
344 cifs_sb
->mnt_cifs_flags
& CIFS_MOUNT_MAP_SPECIAL_CHR
);
346 for (i
= 0; i
< num_referrals
; i
++) {
347 dump_referral(referrals
+i
);
348 /* connect to a storage node */
349 if (referrals
[i
].flags
& DFSREF_STORAGE_SERVER
) {
351 len
= strlen(referrals
[i
].node_name
);
353 cERROR(1, ("%s: Net Address path too short: %s",
354 __func__
, referrals
[i
].node_name
));
358 mnt
= cifs_dfs_do_refmount(nd
->path
.mnt
,
360 referrals
[i
].node_name
);
361 cFYI(1, ("%s: cifs_dfs_do_refmount:%s , mnt:%p",
363 referrals
[i
].node_name
, mnt
));
365 /* complete mount procedure if we accured submount */
371 /* we need it cause for() above could exit without valid submount */
376 nd
->path
.mnt
->mnt_flags
|= MNT_SHRINKABLE
;
377 rc
= add_mount_helper(mnt
, nd
, &cifs_dfs_automount_list
);
381 free_dfs_info_array(referrals
, num_referrals
);
383 cFYI(1, ("leaving %s" , __func__
));
390 struct inode_operations cifs_dfs_referral_inode_operations
= {
391 .follow_link
= cifs_dfs_follow_mountpoint
,