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 cERROR(1, ("%s:2 cant find share name in node name: %s",
98 __func__, node_name));
102 /* trim path up to sharename end
103 * * now we have share name in UNC */
111 * compose_mount_options - creates mount options for refferral
112 * @sb_mountdata: parent/root DFS mount options (template)
113 * @ref_unc: refferral server UNC
114 * @devname: pointer for saving device name
116 * creates mount options for submount based on template options sb_mountdata
117 * and replacing unc,ip,prefixpath options with ones we've got form ref_unc.
119 * Returns: pointer to new mount options or ERR_PTR.
120 * Caller is responcible for freeing retunrned value if it is not error.
122 static char *compose_mount_options(const char *sb_mountdata,
134 if (sb_mountdata == NULL)
135 return ERR_PTR(-EINVAL);
137 *devname = cifs_get_share_name(ref_unc);
138 rc = dns_resolve_server_name_to_ip(*devname, &srvIP);
140 cERROR(1, ("%s: Failed to resolve server part of %s to IP",
141 __func__, *devname));
142 mountdata = ERR_PTR(rc);
143 goto compose_mount_options_out;
145 md_len = strlen(sb_mountdata) + strlen(srvIP) + strlen(ref_unc) + 3;
146 mountdata = kzalloc(md_len+1, GFP_KERNEL);
147 if (mountdata == NULL) {
148 mountdata = ERR_PTR(-ENOMEM);
149 goto compose_mount_options_out;
152 /* copy all options except of unc,ip,prefixpath */
154 if (strncmp(sb_mountdata, "sep=", 4) == 0) {
155 sep = sb_mountdata[4];
156 strncpy(mountdata, sb_mountdata, 5);
159 while ((tkn_e = strchr(sb_mountdata+off, sep))) {
160 noff = (tkn_e - (sb_mountdata+off)) + 1;
161 if (strnicmp(sb_mountdata+off, "unc=", 4) == 0) {
165 if (strnicmp(sb_mountdata+off, "ip=", 3) == 0) {
169 if (strnicmp(sb_mountdata+off, "prefixpath=", 3) == 0) {
173 strncat(mountdata, sb_mountdata+off, noff);
176 strcat(mountdata, sb_mountdata+off);
177 mountdata[md_len] = '\0';
179 /* copy new IP and ref share name */
180 strcat(mountdata, ",ip=");
181 strcat(mountdata, srvIP);
182 strcat(mountdata, ",unc=");
183 strcat(mountdata, *devname);
185 /* find & copy prefixpath */
186 tkn_e = strchr(ref_unc+2, '\\');
188 tkn_e = strchr(tkn_e+1, '\\');
190 strcat(mountdata, ",prefixpath=");
191 strcat(mountdata, tkn_e);
195 /*cFYI(1,("%s: parent mountdata: %s", __func__,sb_mountdata));*/
196 /*cFYI(1, ("%s: submount mountdata: %s", __func__, mountdata ));*/
198 compose_mount_options_out:
204 static struct vfsmount *cifs_dfs_do_refmount(const struct vfsmount *mnt_parent,
205 struct dentry *dentry, char *ref_unc)
207 struct cifs_sb_info *cifs_sb;
208 struct vfsmount *mnt;
210 char *devname = NULL;
212 cifs_sb = CIFS_SB(dentry->d_inode->i_sb);
213 mountdata = compose_mount_options(cifs_sb->mountdata,
216 if (IS_ERR(mountdata))
217 return (struct vfsmount *)mountdata;
219 mnt = vfs_kern_mount(&cifs_fs_type, 0, devname, mountdata);
226 static char *build_full_dfs_path_from_dentry(struct dentry *dentry)
228 char *full_path = NULL;
232 struct cifs_sb_info *cifs_sb;
234 if (dentry->d_inode == NULL)
237 cifs_sb = CIFS_SB(dentry->d_inode->i_sb);
239 if (cifs_sb->tcon == NULL)
242 search_path = build_path_from_dentry(dentry);
243 if (search_path == NULL)
246 if (cifs_sb->tcon->Flags & SMB_SHARE_IS_IN_DFS) {
247 /* we should use full path name to correct working with DFS */
248 l_max_len = strnlen(cifs_sb->tcon->treeName, MAX_TREE_SIZE+1) +
249 strnlen(search_path, MAX_PATHCONF) + 1;
250 tmp_path = kmalloc(l_max_len, GFP_KERNEL);
251 if (tmp_path == NULL) {
255 strncpy(tmp_path, cifs_sb->tcon->treeName, l_max_len);
256 strcat(tmp_path, search_path);
257 tmp_path[l_max_len-1] = 0;
258 full_path = tmp_path;
261 full_path = search_path;
266 static int add_mount_helper(struct vfsmount *newmnt, struct nameidata *nd,
267 struct list_head *mntlist)
269 /* stolen from afs code */
273 err = do_add_mount(newmnt, nd, nd->path.mnt->mnt_flags, mntlist);
277 nd->path.mnt = newmnt;
278 nd->path.dentry = dget(newmnt->mnt_root);
279 schedule_delayed_work(&cifs_dfs_automount_task,
280 cifs_dfs_mountpoint_expiry_timeout);
283 /* someone else made a mount here whilst we were busy */
284 while (d_mountpoint(nd->path.dentry) &&
285 follow_down(&nd->path.mnt, &nd->path.dentry))
295 static void dump_referral(const struct dfs_info3_param *ref)
297 cFYI(1, ("DFS: ref path: %s", ref->path_name));
298 cFYI(1, ("DFS: node path: %s", ref->node_name));
299 cFYI(1, ("DFS: fl: %hd, srv_type: %hd", ref->flags, ref->server_type));
300 cFYI(1, ("DFS: ref_flags: %hd, path_consumed: %hd", ref->ref_flag,
301 ref->path_consumed));
306 cifs_dfs_follow_mountpoint(struct dentry *dentry, struct nameidata *nd)
308 struct dfs_info3_param *referrals = NULL;
309 unsigned int num_referrals = 0;
310 struct cifs_sb_info *cifs_sb;
311 struct cifsSesInfo *ses;
312 char *full_path = NULL;
315 struct vfsmount *mnt = ERR_PTR(-ENOENT);
317 cFYI(1, ("in %s", __func__));
318 BUG_ON(IS_ROOT(dentry));
322 dput(nd->path.dentry);
323 nd->path.dentry = dget(dentry);
325 cifs_sb = CIFS_SB(dentry->d_inode->i_sb);
326 ses = cifs_sb->tcon->ses;
333 full_path = build_full_dfs_path_from_dentry(dentry);
334 if (full_path == NULL) {
339 rc = get_dfs_path(xid, ses , full_path, cifs_sb->local_nls,
340 &num_referrals, &referrals,
341 cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR);
343 for (i = 0; i < num_referrals; i++) {
344 dump_referral(referrals+i);
345 /* connect to a storage node */
346 if (referrals[i].flags & DFSREF_STORAGE_SERVER) {
348 len = strlen(referrals[i].node_name);
350 cERROR(1, ("%s: Net Address path too short: %s",
351 __func__, referrals[i].node_name));
355 mnt = cifs_dfs_do_refmount(nd->path.mnt,
357 referrals[i].node_name);
358 cFYI(1, ("%s: cifs_dfs_do_refmount:%s , mnt:%p",
360 referrals[i].node_name, mnt));
362 /* complete mount procedure if we accured submount */
368 /* we need it cause for() above could exit without valid submount */
373 nd->path.mnt->mnt_flags |= MNT_SHRINKABLE;
374 rc = add_mount_helper(mnt, nd, &cifs_dfs_automount_list);
378 free_dfs_info_array(referrals, num_referrals);
380 cFYI(1, ("leaving %s" , __func__));
387 struct inode_operations cifs_dfs_referral_inode_operations = {
388 .follow_link = cifs_dfs_follow_mountpoint,