USB: EHCI: carry out port handover during each root-hub resume
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / fs / cifs / cifs_dfs_ref.c
blobf53f41ff16653622755973ebf1b7880bf8a0ca09
1 /*
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>
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"
26 static LIST_HEAD(cifs_dfs_automount_list);
29 * DFS functions
32 void dfs_shrink_umount_helper(struct vfsmount *vfsmnt)
34 mark_mounts_for_expiry(&cifs_dfs_automount_list);
35 mark_mounts_for_expiry(&cifs_dfs_automount_list);
38 /**
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
45 * if neccessary.
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)
51 int len;
52 char *UNC;
53 char *pSep;
55 len = strlen(node_name);
56 UNC = kmalloc(len+2 /*for term null and additional \ if it's missed */,
57 GFP_KERNEL);
58 if (!UNC)
59 return NULL;
61 /* get share name and server name */
62 if (node_name[1] != '\\') {
63 UNC[0] = '\\';
64 strncpy(UNC+1, node_name, len);
65 len++;
66 UNC[len] = 0;
67 } else {
68 strncpy(UNC, node_name, len);
69 UNC[len] = 0;
72 /* find server name end */
73 pSep = memchr(UNC+2, '\\', len-2);
74 if (!pSep) {
75 cERROR(1, ("%s: no server name end in node name: %s",
76 __func__, node_name));
77 kfree(UNC);
78 return NULL;
81 /* find sharename end */
82 pSep++;
83 pSep = memchr(UNC+(pSep-UNC), '\\', len-(pSep-UNC));
84 if (!pSep) {
85 cERROR(1, ("%s:2 cant find share name in node name: %s",
86 __func__, node_name));
87 kfree(UNC);
88 return NULL;
90 /* trim path up to sharename end
91 * * now we have share name in UNC */
92 *pSep = 0;
94 return UNC;
98 /**
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 static char *compose_mount_options(const char *sb_mountdata,
111 const char *ref_unc,
112 char **devname)
114 int rc;
115 char *mountdata;
116 int md_len;
117 char *tkn_e;
118 char *srvIP = NULL;
119 char sep = ',';
120 int off, noff;
122 if (sb_mountdata == NULL)
123 return ERR_PTR(-EINVAL);
125 *devname = cifs_get_share_name(ref_unc);
126 rc = dns_resolve_server_name_to_ip(*devname, &srvIP);
127 if (rc != 0) {
128 cERROR(1, ("%s: Failed to resolve server part of %s to IP",
129 __func__, *devname));
130 mountdata = ERR_PTR(rc);
131 goto compose_mount_options_out;
133 md_len = strlen(sb_mountdata) + strlen(srvIP) + strlen(ref_unc) + 3;
134 mountdata = kzalloc(md_len+1, GFP_KERNEL);
135 if (mountdata == NULL) {
136 mountdata = ERR_PTR(-ENOMEM);
137 goto compose_mount_options_out;
140 /* copy all options except of unc,ip,prefixpath */
141 off = 0;
142 if (strncmp(sb_mountdata, "sep=", 4) == 0) {
143 sep = sb_mountdata[4];
144 strncpy(mountdata, sb_mountdata, 5);
145 off += 5;
147 while ((tkn_e = strchr(sb_mountdata+off, sep))) {
148 noff = (tkn_e - (sb_mountdata+off)) + 1;
149 if (strnicmp(sb_mountdata+off, "unc=", 4) == 0) {
150 off += noff;
151 continue;
153 if (strnicmp(sb_mountdata+off, "ip=", 3) == 0) {
154 off += noff;
155 continue;
157 if (strnicmp(sb_mountdata+off, "prefixpath=", 3) == 0) {
158 off += noff;
159 continue;
161 strncat(mountdata, sb_mountdata+off, noff);
162 off += noff;
164 strcat(mountdata, sb_mountdata+off);
165 mountdata[md_len] = '\0';
167 /* copy new IP and ref share name */
168 strcat(mountdata, ",ip=");
169 strcat(mountdata, srvIP);
170 strcat(mountdata, ",unc=");
171 strcat(mountdata, *devname);
173 /* find & copy prefixpath */
174 tkn_e = strchr(ref_unc+2, '\\');
175 if (tkn_e) {
176 tkn_e = strchr(tkn_e+1, '\\');
177 if (tkn_e) {
178 strcat(mountdata, ",prefixpath=");
179 strcat(mountdata, tkn_e);
183 /*cFYI(1,("%s: parent mountdata: %s", __func__,sb_mountdata));*/
184 /*cFYI(1, ("%s: submount mountdata: %s", __func__, mountdata ));*/
186 compose_mount_options_out:
187 kfree(srvIP);
188 return mountdata;
192 static struct vfsmount *cifs_dfs_do_refmount(const struct vfsmount *mnt_parent,
193 struct dentry *dentry, char *ref_unc)
195 struct cifs_sb_info *cifs_sb;
196 struct vfsmount *mnt;
197 char *mountdata;
198 char *devname = NULL;
200 cifs_sb = CIFS_SB(dentry->d_inode->i_sb);
201 mountdata = compose_mount_options(cifs_sb->mountdata,
202 ref_unc, &devname);
204 if (IS_ERR(mountdata))
205 return (struct vfsmount *)mountdata;
207 mnt = vfs_kern_mount(&cifs_fs_type, 0, devname, mountdata);
208 kfree(mountdata);
209 kfree(devname);
210 return mnt;
214 static char *build_full_dfs_path_from_dentry(struct dentry *dentry)
216 char *full_path = NULL;
217 char *search_path;
218 char *tmp_path;
219 size_t l_max_len;
220 struct cifs_sb_info *cifs_sb;
222 if (dentry->d_inode == NULL)
223 return NULL;
225 cifs_sb = CIFS_SB(dentry->d_inode->i_sb);
227 if (cifs_sb->tcon == NULL)
228 return NULL;
230 search_path = build_path_from_dentry(dentry);
231 if (search_path == NULL)
232 return NULL;
234 if (cifs_sb->tcon->Flags & SMB_SHARE_IS_IN_DFS) {
235 /* we should use full path name to correct working with DFS */
236 l_max_len = strnlen(cifs_sb->tcon->treeName, MAX_TREE_SIZE+1) +
237 strnlen(search_path, MAX_PATHCONF) + 1;
238 tmp_path = kmalloc(l_max_len, GFP_KERNEL);
239 if (tmp_path == NULL) {
240 kfree(search_path);
241 return NULL;
243 strncpy(tmp_path, cifs_sb->tcon->treeName, l_max_len);
244 strcat(tmp_path, search_path);
245 tmp_path[l_max_len-1] = 0;
246 full_path = tmp_path;
247 kfree(search_path);
248 } else {
249 full_path = search_path;
251 return full_path;
254 static int add_mount_helper(struct vfsmount *newmnt, struct nameidata *nd,
255 struct list_head *mntlist)
257 /* stolen from afs code */
258 int err;
260 mntget(newmnt);
261 err = do_add_mount(newmnt, nd, nd->path.mnt->mnt_flags, mntlist);
262 switch (err) {
263 case 0:
264 dput(nd->path.dentry);
265 mntput(nd->path.mnt);
266 nd->path.mnt = newmnt;
267 nd->path.dentry = dget(newmnt->mnt_root);
268 break;
269 case -EBUSY:
270 /* someone else made a mount here whilst we were busy */
271 while (d_mountpoint(nd->path.dentry) &&
272 follow_down(&nd->path.mnt, &nd->path.dentry))
274 err = 0;
275 default:
276 mntput(newmnt);
277 break;
279 return err;
282 static void dump_referral(const struct dfs_info3_param *ref)
284 cFYI(1, ("DFS: ref path: %s", ref->path_name));
285 cFYI(1, ("DFS: node path: %s", ref->node_name));
286 cFYI(1, ("DFS: fl: %hd, srv_type: %hd", ref->flags, ref->server_type));
287 cFYI(1, ("DFS: ref_flags: %hd, path_consumed: %hd", ref->ref_flag,
288 ref->path_consumed));
292 static void*
293 cifs_dfs_follow_mountpoint(struct dentry *dentry, struct nameidata *nd)
295 struct dfs_info3_param *referrals = NULL;
296 unsigned int num_referrals = 0;
297 struct cifs_sb_info *cifs_sb;
298 struct cifsSesInfo *ses;
299 char *full_path = NULL;
300 int xid, i;
301 int rc = 0;
302 struct vfsmount *mnt = ERR_PTR(-ENOENT);
304 cFYI(1, ("in %s", __func__));
305 BUG_ON(IS_ROOT(dentry));
307 xid = GetXid();
309 dput(nd->path.dentry);
310 nd->path.dentry = dget(dentry);
312 cifs_sb = CIFS_SB(dentry->d_inode->i_sb);
313 ses = cifs_sb->tcon->ses;
315 if (!ses) {
316 rc = -EINVAL;
317 goto out_err;
320 full_path = build_full_dfs_path_from_dentry(dentry);
321 if (full_path == NULL) {
322 rc = -ENOMEM;
323 goto out_err;
326 rc = get_dfs_path(xid, ses , full_path, cifs_sb->local_nls,
327 &num_referrals, &referrals,
328 cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR);
330 for (i = 0; i < num_referrals; i++) {
331 dump_referral(referrals+i);
332 /* connect to a storage node */
333 if (referrals[i].flags & DFSREF_STORAGE_SERVER) {
334 int len;
335 len = strlen(referrals[i].node_name);
336 if (len < 2) {
337 cERROR(1, ("%s: Net Address path too short: %s",
338 __func__, referrals[i].node_name));
339 rc = -EINVAL;
340 goto out_err;
342 mnt = cifs_dfs_do_refmount(nd->path.mnt,
343 nd->path.dentry,
344 referrals[i].node_name);
345 cFYI(1, ("%s: cifs_dfs_do_refmount:%s , mnt:%p",
346 __func__,
347 referrals[i].node_name, mnt));
349 /* complete mount procedure if we accured submount */
350 if (!IS_ERR(mnt))
351 break;
355 /* we need it cause for() above could exit without valid submount */
356 rc = PTR_ERR(mnt);
357 if (IS_ERR(mnt))
358 goto out_err;
360 nd->path.mnt->mnt_flags |= MNT_SHRINKABLE;
361 rc = add_mount_helper(mnt, nd, &cifs_dfs_automount_list);
363 out:
364 FreeXid(xid);
365 free_dfs_info_array(referrals, num_referrals);
366 kfree(full_path);
367 cFYI(1, ("leaving %s" , __func__));
368 return ERR_PTR(rc);
369 out_err:
370 path_put(&nd->path);
371 goto out;
374 struct inode_operations cifs_dfs_referral_inode_operations = {
375 .follow_link = cifs_dfs_follow_mountpoint,