blob: d2c8eef84f3c7c805d8a484115ae090bc56e8920 [file] [log] [blame]
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +00001/*
2 * Contains the CIFS DFS referral mounting routines used for handling
3 * traversal via DFS junction point
4 *
5 * Copyright (c) 2007 Igor Mammedov
Steve French366781c2008-01-25 10:12:41 +00006 * Copyright (C) International Business Machines Corp., 2008
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +00007 * Author(s): Igor Mammedov (niallain@gmail.com)
Steve French366781c2008-01-25 10:12:41 +00008 * Steve French (sfrench@us.ibm.com)
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +00009 * 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
Steve French8d142132008-04-16 03:56:51 +000026static LIST_HEAD(cifs_dfs_automount_list);
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +000027
Igor Mammedov78d31a32008-04-24 12:56:07 +040028static void cifs_dfs_expire_automounts(struct work_struct *work);
29static DECLARE_DELAYED_WORK(cifs_dfs_automount_task,
30 cifs_dfs_expire_automounts);
31static int cifs_dfs_mountpoint_expiry_timeout = 500 * HZ;
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +000032
Igor Mammedov78d31a32008-04-24 12:56:07 +040033static void cifs_dfs_expire_automounts(struct work_struct *work)
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +000034{
Igor Mammedov78d31a32008-04-24 12:56:07 +040035 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}
42
43void cifs_dfs_release_automount_timer(void)
44{
45 BUG_ON(!list_empty(&cifs_dfs_automount_list));
46 cancel_delayed_work(&cifs_dfs_automount_task);
47 flush_scheduled_work();
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +000048}
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 */
61static 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",
Harvey Harrison55f78e12008-03-10 17:14:34 +000088 __func__, node_name));
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +000089 kfree(UNC);
90 return NULL;
91 }
92
93 /* find sharename end */
94 pSep++;
95 pSep = memchr(UNC+(pSep-UNC), '\\', len-(pSep-UNC));
Igor Mammedovbf62fd82008-04-28 23:05:58 +000096 if (pSep) {
97 /* trim path up to sharename end
98 * now we have share name in UNC */
99 *pSep = 0;
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000100 }
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000101
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 */
Steve French366781c2008-01-25 10:12:41 +0000118static char *compose_mount_options(const char *sb_mountdata,
119 const char *ref_unc,
120 char **devname)
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000121{
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",
Harvey Harrison55f78e12008-03-10 17:14:34 +0000137 __func__, *devname));
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000138 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=");
Igor Mammedovbf62fd82008-04-28 23:05:58 +0000187 strcat(mountdata, tkn_e+1);
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000188 }
189 }
190
Harvey Harrison55f78e12008-03-10 17:14:34 +0000191 /*cFYI(1,("%s: parent mountdata: %s", __func__,sb_mountdata));*/
192 /*cFYI(1, ("%s: submount mountdata: %s", __func__, mountdata ));*/
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000193
194compose_mount_options_out:
195 kfree(srvIP);
196 return mountdata;
197}
198
199
Steve French366781c2008-01-25 10:12:41 +0000200static struct vfsmount *cifs_dfs_do_refmount(const struct vfsmount *mnt_parent,
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000201 struct dentry *dentry, char *ref_unc)
202{
203 struct cifs_sb_info *cifs_sb;
204 struct vfsmount *mnt;
205 char *mountdata;
Steve French366781c2008-01-25 10:12:41 +0000206 char *devname = NULL;
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000207
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
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000222static 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);
Al Viro8d66bf52008-08-01 09:05:54 -0400229 err = do_add_mount(newmnt, &nd->path, nd->path.mnt->mnt_flags, mntlist);
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000230 switch (err) {
231 case 0:
Igor Mammedov78d31a32008-04-24 12:56:07 +0400232 path_put(&nd->path);
Jan Blunck4ac91372008-02-14 19:34:32 -0800233 nd->path.mnt = newmnt;
234 nd->path.dentry = dget(newmnt->mnt_root);
Igor Mammedov78d31a32008-04-24 12:56:07 +0400235 schedule_delayed_work(&cifs_dfs_automount_task,
236 cifs_dfs_mountpoint_expiry_timeout);
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000237 break;
238 case -EBUSY:
239 /* someone else made a mount here whilst we were busy */
Jan Blunck4ac91372008-02-14 19:34:32 -0800240 while (d_mountpoint(nd->path.dentry) &&
241 follow_down(&nd->path.mnt, &nd->path.dentry))
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000242 ;
243 err = 0;
244 default:
245 mntput(newmnt);
246 break;
247 }
248 return err;
249}
250
Steve French366781c2008-01-25 10:12:41 +0000251static void dump_referral(const struct dfs_info3_param *ref)
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000252{
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,
Igor Mammedov8aad0182008-02-15 18:21:49 +0000257 ref->path_consumed));
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000258}
259
260
261static void*
262cifs_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
Harvey Harrison55f78e12008-03-10 17:14:34 +0000273 cFYI(1, ("in %s", __func__));
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000274 BUG_ON(IS_ROOT(dentry));
275
276 xid = GetXid();
277
Jan Blunck4ac91372008-02-14 19:34:32 -0800278 dput(nd->path.dentry);
279 nd->path.dentry = dget(dentry);
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000280
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
Igor Mammedovde2db8d2008-05-16 13:10:32 +0400289 full_path = build_path_from_dentry(dentry);
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000290 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",
Harvey Harrison55f78e12008-03-10 17:14:34 +0000307 __func__, referrals[i].node_name));
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000308 rc = -EINVAL;
309 goto out_err;
310 }
Jan Blunck4ac91372008-02-14 19:34:32 -0800311 mnt = cifs_dfs_do_refmount(nd->path.mnt,
312 nd->path.dentry,
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000313 referrals[i].node_name);
314 cFYI(1, ("%s: cifs_dfs_do_refmount:%s , mnt:%p",
Harvey Harrison55f78e12008-03-10 17:14:34 +0000315 __func__,
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000316 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
Jan Blunck4ac91372008-02-14 19:34:32 -0800329 nd->path.mnt->mnt_flags |= MNT_SHRINKABLE;
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000330 rc = add_mount_helper(mnt, nd, &cifs_dfs_automount_list);
331
332out:
333 FreeXid(xid);
334 free_dfs_info_array(referrals, num_referrals);
335 kfree(full_path);
Harvey Harrison55f78e12008-03-10 17:14:34 +0000336 cFYI(1, ("leaving %s" , __func__));
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000337 return ERR_PTR(rc);
338out_err:
Jan Blunck1d957f92008-02-14 19:34:35 -0800339 path_put(&nd->path);
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000340 goto out;
341}
342
343struct inode_operations cifs_dfs_referral_inode_operations = {
344 .follow_link = cifs_dfs_follow_mountpoint,
345};
346