2 * Contains the CIFS DFS referral mounting routines used for handling
3 * traversal via DFS junction point
5 * Copyright (c) 2007 Igor Mammedov
6 * Author(s): Igor Mammedov (niallain@gmail.com)
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License
10 * as published by the Free Software Foundation; either version
11 * 2 of the License, or (at your option) any later version.
14 #include <linux/dcache.h>
15 #include <linux/mount.h>
16 #include <linux/namei.h>
17 #include <linux/vfs.h>
20 #include "cifsproto.h"
22 #include "dns_resolve.h"
23 #include "cifs_debug.h"
25 LIST_HEAD(cifs_dfs_automount_list);
31 void dfs_shrink_umount_helper(struct vfsmount *vfsmnt)
33 mark_mounts_for_expiry(&cifs_dfs_automount_list);
34 mark_mounts_for_expiry(&cifs_dfs_automount_list);
35 shrink_submounts(vfsmnt, &cifs_dfs_automount_list);
39 * cifs_get_share_name - extracts share name from UNC
40 * @node_name: pointer to UNC string
42 * Extracts sharename form full UNC.
43 * i.e. strips from UNC trailing path that is not part of share
44 * name and fixup missing '\' in the begining of DFS node refferal
46 * Returns pointer to share name on success or NULL on error.
47 * Caller is responsible for freeing returned string.
49 static char *cifs_get_share_name(const char *node_name)
55 len = strlen(node_name);
56 UNC = kmalloc(len+2 /*for term null and additional \ if it's missed */,
61 /* get share name and server name */
62 if (node_name[1] != '\\') {
64 strncpy(UNC+1, node_name, len);
68 strncpy(UNC, node_name, len);
72 /* find server name end */
73 pSep = memchr(UNC+2, '\\', len-2);
75 cERROR(1, ("%s: no server name end in node name: %s",
76 __FUNCTION__, node_name));
81 /* find sharename end */
83 pSep = memchr(UNC+(pSep-UNC), '\\', len-(pSep-UNC));
85 cERROR(1, ("%s:2 cant find share name in node name: %s",
86 __FUNCTION__, node_name));
90 /* trim path up to sharename end
91 * * now we have share name in UNC */
99 * compose_mount_options - creates mount options for refferral
100 * @sb_mountdata: parent/root DFS mount options (template)
101 * @ref_unc: refferral server UNC
102 * @devname: pointer for saving device name
104 * creates mount options for submount based on template options sb_mountdata
105 * and replacing unc,ip,prefixpath options with ones we've got form ref_unc.
107 * Returns: pointer to new mount options or ERR_PTR.
108 * Caller is responcible for freeing retunrned value if it is not error.
110 char *compose_mount_options(const char *sb_mountdata, const char *ref_unc,
121 if (sb_mountdata == NULL)
122 return ERR_PTR(-EINVAL);
124 *devname = cifs_get_share_name(ref_unc);
125 rc = dns_resolve_server_name_to_ip(*devname, &srvIP);
127 cERROR(1, ("%s: Failed to resolve server part of %s to IP",
128 __FUNCTION__, *devname));
129 mountdata = ERR_PTR(rc);
130 goto compose_mount_options_out;
132 md_len = strlen(sb_mountdata) + strlen(srvIP) + strlen(ref_unc) + 3;
133 mountdata = kzalloc(md_len+1, GFP_KERNEL);
134 if (mountdata == NULL) {
135 mountdata = ERR_PTR(-ENOMEM);
136 goto compose_mount_options_out;
139 /* copy all options except of unc,ip,prefixpath */
141 if (strncmp(sb_mountdata, "sep=", 4) == 0) {
142 sep = sb_mountdata[4];
143 strncpy(mountdata, sb_mountdata, 5);
146 while ((tkn_e = strchr(sb_mountdata+off, sep))) {
147 noff = (tkn_e - (sb_mountdata+off)) + 1;
148 if (strnicmp(sb_mountdata+off, "unc=", 4) == 0) {
152 if (strnicmp(sb_mountdata+off, "ip=", 3) == 0) {
156 if (strnicmp(sb_mountdata+off, "prefixpath=", 3) == 0) {
160 strncat(mountdata, sb_mountdata+off, noff);
163 strcat(mountdata, sb_mountdata+off);
164 mountdata[md_len] = '\0';
166 /* copy new IP and ref share name */
167 strcat(mountdata, ",ip=");
168 strcat(mountdata, srvIP);
169 strcat(mountdata, ",unc=");
170 strcat(mountdata, *devname);
172 /* find & copy prefixpath */
173 tkn_e = strchr(ref_unc+2, '\\');
175 tkn_e = strchr(tkn_e+1, '\\');
177 strcat(mountdata, ",prefixpath=");
178 strcat(mountdata, tkn_e);
182 /*cFYI(1,("%s: parent mountdata: %s", __FUNCTION__,sb_mountdata));*/
183 /*cFYI(1, ("%s: submount mountdata: %s", __FUNCTION__, mountdata ));*/
185 compose_mount_options_out:
191 struct vfsmount *cifs_dfs_do_refmount(const struct vfsmount *mnt_parent,
192 struct dentry *dentry, char *ref_unc)
194 struct cifs_sb_info *cifs_sb;
195 struct vfsmount *mnt;
199 cifs_sb = CIFS_SB(dentry->d_inode->i_sb);
200 mountdata = compose_mount_options(cifs_sb->mountdata,
203 if (IS_ERR(mountdata))
204 return (struct vfsmount *)mountdata;
206 mnt = vfs_kern_mount(&cifs_fs_type, 0, devname, mountdata);
213 static char *build_full_dfs_path_from_dentry(struct dentry *dentry)
215 char *full_path = NULL;
219 struct cifs_sb_info *cifs_sb;
221 if (dentry->d_inode == NULL)
224 cifs_sb = CIFS_SB(dentry->d_inode->i_sb);
226 if (cifs_sb->tcon == NULL)
229 search_path = build_path_from_dentry(dentry);
230 if (search_path == NULL)
233 if (cifs_sb->tcon->Flags & SMB_SHARE_IS_IN_DFS) {
234 /* we should use full path name to correct working with DFS */
235 l_max_len = strnlen(cifs_sb->tcon->treeName, MAX_TREE_SIZE+1) +
236 strnlen(search_path, MAX_PATHCONF) + 1;
237 tmp_path = kmalloc(l_max_len, GFP_KERNEL);
238 if (tmp_path == NULL) {
242 strncpy(tmp_path, cifs_sb->tcon->treeName, l_max_len);
243 strcat(tmp_path, search_path);
244 tmp_path[l_max_len-1] = 0;
245 full_path = tmp_path;
248 full_path = search_path;
253 static int add_mount_helper(struct vfsmount *newmnt, struct nameidata *nd,
254 struct list_head *mntlist)
256 /* stolen from afs code */
260 err = do_add_mount(newmnt, nd, nd->mnt->mnt_flags, mntlist);
266 nd->dentry = dget(newmnt->mnt_root);
269 /* someone else made a mount here whilst we were busy */
270 while (d_mountpoint(nd->dentry) &&
271 follow_down(&nd->mnt, &nd->dentry))
281 void dump_referral(const struct dfs_info3_param *ref)
283 cFYI(1, ("DFS: ref path: %s", ref->path_name));
284 cFYI(1, ("DFS: node path: %s", ref->node_name));
285 cFYI(1, ("DFS: fl: %hd, srv_type: %hd", ref->flags, ref->server_type));
286 cFYI(1, ("DFS: ref_flags: %hd, path_consumed: %hd", ref->ref_flag,
292 cifs_dfs_follow_mountpoint(struct dentry *dentry, struct nameidata *nd)
294 struct dfs_info3_param *referrals = NULL;
295 unsigned int num_referrals = 0;
296 struct cifs_sb_info *cifs_sb;
297 struct cifsSesInfo *ses;
298 char *full_path = NULL;
301 struct vfsmount *mnt = ERR_PTR(-ENOENT);
303 cFYI(1, ("in %s", __FUNCTION__));
304 BUG_ON(IS_ROOT(dentry));
309 nd->dentry = dget(dentry);
311 cifs_sb = CIFS_SB(dentry->d_inode->i_sb);
312 ses = cifs_sb->tcon->ses;
319 full_path = build_full_dfs_path_from_dentry(dentry);
320 if (full_path == NULL) {
325 rc = get_dfs_path(xid, ses , full_path, cifs_sb->local_nls,
326 &num_referrals, &referrals,
327 cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR);
329 for (i = 0; i < num_referrals; i++) {
330 dump_referral(referrals+i);
331 /* connect to a storage node */
332 if (referrals[i].flags & DFSREF_STORAGE_SERVER) {
334 len = strlen(referrals[i].node_name);
336 cERROR(1, ("%s: Net Address path too short: %s",
337 __FUNCTION__, referrals[i].node_name));
341 mnt = cifs_dfs_do_refmount(nd->mnt, nd->dentry,
342 referrals[i].node_name);
343 cFYI(1, ("%s: cifs_dfs_do_refmount:%s , mnt:%p",
345 referrals[i].node_name, mnt));
347 /* complete mount procedure if we accured submount */
353 /* we need it cause for() above could exit without valid submount */
358 nd->mnt->mnt_flags |= MNT_SHRINKABLE;
359 rc = add_mount_helper(mnt, nd, &cifs_dfs_automount_list);
363 free_dfs_info_array(referrals, num_referrals);
365 cFYI(1, ("leaving %s" , __FUNCTION__));
372 struct inode_operations cifs_dfs_referral_inode_operations = {
373 .follow_link = cifs_dfs_follow_mountpoint,