aboutsummaryrefslogtreecommitdiffstats
path: root/fs
diff options
context:
space:
mode:
authorIgor Mammedov <niallain@gmail.com>2008-01-24 22:28:31 -0500
committerSteve French <sfrench@us.ibm.com>2008-01-24 22:28:31 -0500
commit6d5ae0deb1641bf615eafd8fef64218e10cb2fd0 (patch)
tree5b0d74ad31ce50534563bb1b7e6e06c4d3fdb4f9 /fs
parented2b91701d97047fa9970645e43d5e551e261adb (diff)
[CIFS] DFS support: provide shrinkable mounts
Signed-off-by: Igor Mammedov <niallain@gmail.com> Signed-off-by: Steve French <sfrench@us.ibm.com>
Diffstat (limited to 'fs')
-rw-r--r--fs/cifs/Makefile2
-rw-r--r--fs/cifs/cifs_dfs_ref.c375
-rw-r--r--fs/cifs/cifsfs.c4
-rw-r--r--fs/cifs/cifsfs.h4
-rw-r--r--fs/cifs/cifsproto.h3
5 files changed, 387 insertions, 1 deletions
diff --git a/fs/cifs/Makefile b/fs/cifs/Makefile
index 09898b8dc69b..6ba43fb346fb 100644
--- a/fs/cifs/Makefile
+++ b/fs/cifs/Makefile
@@ -10,4 +10,4 @@ cifs-y := cifsfs.o cifssmb.o cifs_debug.o connect.o dir.o file.o inode.o \
10 10
11cifs-$(CONFIG_CIFS_UPCALL) += cifs_spnego.o 11cifs-$(CONFIG_CIFS_UPCALL) += cifs_spnego.o
12 12
13cifs-$(CONFIG_CIFS_DFS_UPCALL) += dns_resolve.o 13cifs-$(CONFIG_CIFS_DFS_UPCALL) += dns_resolve.o cifs_dfs_ref.o
diff --git a/fs/cifs/cifs_dfs_ref.c b/fs/cifs/cifs_dfs_ref.c
new file mode 100644
index 000000000000..15e31f8435ba
--- /dev/null
+++ b/fs/cifs/cifs_dfs_ref.c
@@ -0,0 +1,375 @@
1/*
2 * Contains the CIFS DFS referral mounting routines used for handling
3 * traversal via DFS junction point
4 *
5 * Copyright (c) 2007 Igor Mammedov
6 * Author(s): Igor Mammedov (niallain@gmail.com)
7 *
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.
12 */
13
14#include <linux/dcache.h>
15#include <linux/mount.h>
16#include <linux/namei.h>
17#include <linux/vfs.h>
18#include <linux/fs.h>
19#include "cifsglob.h"
20#include "cifsproto.h"
21#include "cifsfs.h"
22#include "dns_resolve.h"
23#include "cifs_debug.h"
24
25LIST_HEAD(cifs_dfs_automount_list);
26
27/*
28 * DFS functions
29*/
30
31void dfs_shrink_umount_helper(struct vfsmount *vfsmnt)
32{
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);
36}
37
38/**
39 * cifs_get_share_name - extracts share name from UNC
40 * @node_name: pointer to UNC string
41 *
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.
48 */
49static char *cifs_get_share_name(const char *node_name)
50{
51 int len;
52 char *UNC;
53 char *pSep;
54
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;
60
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;
70 }
71
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 __FUNCTION__, node_name));
77 kfree(UNC);
78 return NULL;
79 }
80
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 __FUNCTION__, node_name));
87 kfree(UNC);
88 return NULL;
89 }
90 /* trim path up to sharename end
91 * * now we have share name in UNC */
92 *pSep = 0;
93
94 return UNC;
95}
96
97
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
103 *
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.
106 *
107 * Returns: pointer to new mount options or ERR_PTR.
108 * Caller is responcible for freeing retunrned value if it is not error.
109 */
110char *compose_mount_options(const char *sb_mountdata, const char *ref_unc,
111 char **devname)
112{
113 int rc;
114 char *mountdata;
115 int md_len;
116 char *tkn_e;
117 char *srvIP = NULL;
118 char sep = ',';
119 int off, noff;
120
121 if (sb_mountdata == NULL)
122 return ERR_PTR(-EINVAL);
123
124 *devname = cifs_get_share_name(ref_unc);
125 rc = dns_resolve_server_name_to_ip(*devname, &srvIP);
126 if (rc != 0) {
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;
131 }
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;
137 }
138
139 /* copy all options except of unc,ip,prefixpath */
140 off = 0;
141 if (strncmp(sb_mountdata, "sep=", 4) == 0) {
142 sep = sb_mountdata[4];
143 strncpy(mountdata, sb_mountdata, 5);
144 off += 5;
145 }
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) {
149 off += noff;
150 continue;
151 }
152 if (strnicmp(sb_mountdata+off, "ip=", 3) == 0) {
153 off += noff;
154 continue;
155 }
156 if (strnicmp(sb_mountdata+off, "prefixpath=", 3) == 0) {
157 off += noff;
158 continue;
159 }
160 strncat(mountdata, sb_mountdata+off, noff);
161 off += noff;
162 }
163 strcat(mountdata, sb_mountdata+off);
164 mountdata[md_len] = '\0';
165
166 /* copy new IP and ref share name */
167 strcat(mountdata, ",ip=");
168 strcat(mountdata, srvIP);
169 strcat(mountdata, ",unc=");
170 strcat(mountdata, *devname);
171
172 /* find & copy prefixpath */
173 tkn_e = strchr(ref_unc+2, '\\');
174 if (tkn_e) {
175 tkn_e = strchr(tkn_e+1, '\\');
176 if (tkn_e) {
177 strcat(mountdata, ",prefixpath=");
178 strcat(mountdata, tkn_e);
179 }
180 }
181
182 /*cFYI(1,("%s: parent mountdata: %s", __FUNCTION__,sb_mountdata));*/
183 /*cFYI(1, ("%s: submount mountdata: %s", __FUNCTION__, mountdata ));*/
184
185compose_mount_options_out:
186 kfree(srvIP);
187 return mountdata;
188}
189
190
191struct vfsmount *cifs_dfs_do_refmount(const struct vfsmount *mnt_parent,
192 struct dentry *dentry, char *ref_unc)
193{
194 struct cifs_sb_info *cifs_sb;
195 struct vfsmount *mnt;
196 char *mountdata;
197 char *devname;
198
199 cifs_sb = CIFS_SB(dentry->d_inode->i_sb);
200 mountdata = compose_mount_options(cifs_sb->mountdata,
201 ref_unc, &devname);
202
203 if (IS_ERR(mountdata))
204 return (struct vfsmount *)mountdata;
205
206 mnt = vfs_kern_mount(&cifs_fs_type, 0, devname, mountdata);
207 kfree(mountdata);
208 kfree(devname);
209 return mnt;
210
211}
212
213static char *build_full_dfs_path_from_dentry(struct dentry *dentry)
214{
215 char *full_path = NULL;
216 char *search_path;
217 char *tmp_path;
218 size_t l_max_len;
219 struct cifs_sb_info *cifs_sb;
220
221 if (dentry->d_inode == NULL)
222 return NULL;
223
224 cifs_sb = CIFS_SB(dentry->d_inode->i_sb);
225
226 if (cifs_sb->tcon == NULL)
227 return NULL;
228
229 search_path = build_path_from_dentry(dentry);
230 if (search_path == NULL)
231 return NULL;
232
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) {
239 kfree(search_path);
240 return NULL;
241 }
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;
246 kfree(search_path);
247 } else {
248 full_path = search_path;
249 }
250 return full_path;
251}
252
253static int add_mount_helper(struct vfsmount *newmnt, struct nameidata *nd,
254 struct list_head *mntlist)
255{
256 /* stolen from afs code */
257 int err;
258
259 mntget(newmnt);
260 err = do_add_mount(newmnt, nd, nd->mnt->mnt_flags, mntlist);
261 switch (err) {
262 case 0:
263 dput(nd->dentry);
264 mntput(nd->mnt);
265 nd->mnt = newmnt;
266 nd->dentry = dget(newmnt->mnt_root);
267 break;
268 case -EBUSY:
269 /* someone else made a mount here whilst we were busy */
270 while (d_mountpoint(nd->dentry) &&
271 follow_down(&nd->mnt, &nd->dentry))
272 ;
273 err = 0;
274 default:
275 mntput(newmnt);
276 break;
277 }
278 return err;
279}
280
281void dump_referral(const struct dfs_info3_param *ref)
282{
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,
287 ref->PathConsumed));
288}
289
290
291static void*
292cifs_dfs_follow_mountpoint(struct dentry *dentry, struct nameidata *nd)
293{
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;
299 int xid, i;
300 int rc = 0;
301 struct vfsmount *mnt = ERR_PTR(-ENOENT);
302
303 cFYI(1, ("in %s", __FUNCTION__));
304 BUG_ON(IS_ROOT(dentry));
305
306 xid = GetXid();
307
308 dput(nd->dentry);
309 nd->dentry = dget(dentry);
310
311 cifs_sb = CIFS_SB(dentry->d_inode->i_sb);
312 ses = cifs_sb->tcon->ses;
313
314 if (!ses) {
315 rc = -EINVAL;
316 goto out_err;
317 }
318
319 full_path = build_full_dfs_path_from_dentry(dentry);
320 if (full_path == NULL) {
321 rc = -ENOMEM;
322 goto out_err;
323 }
324
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);
328
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) {
333 int len;
334 len = strlen(referrals[i].node_name);
335 if (len < 2) {
336 cERROR(1, ("%s: Net Address path too short: %s",
337 __FUNCTION__, referrals[i].node_name));
338 rc = -EINVAL;
339 goto out_err;
340 }
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",
344 __FUNCTION__,
345 referrals[i].node_name, mnt));
346
347 /* complete mount procedure if we accured submount */
348 if (!IS_ERR(mnt))
349 break;
350 }
351 }
352
353 /* we need it cause for() above could exit without valid submount */
354 rc = PTR_ERR(mnt);
355 if (IS_ERR(mnt))
356 goto out_err;
357
358 nd->mnt->mnt_flags |= MNT_SHRINKABLE;
359 rc = add_mount_helper(mnt, nd, &cifs_dfs_automount_list);
360
361out:
362 FreeXid(xid);
363 free_dfs_info_array(referrals, num_referrals);
364 kfree(full_path);
365 cFYI(1, ("leaving %s" , __FUNCTION__));
366 return ERR_PTR(rc);
367out_err:
368 path_release(nd);
369 goto out;
370}
371
372struct inode_operations cifs_dfs_referral_inode_operations = {
373 .follow_link = cifs_dfs_follow_mountpoint,
374};
375
diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
index 93e107883a61..e9f4ec701092 100644
--- a/fs/cifs/cifsfs.c
+++ b/fs/cifs/cifsfs.c
@@ -471,6 +471,10 @@ static void cifs_umount_begin(struct vfsmount *vfsmnt, int flags)
471 struct cifs_sb_info *cifs_sb; 471 struct cifs_sb_info *cifs_sb;
472 struct cifsTconInfo *tcon; 472 struct cifsTconInfo *tcon;
473 473
474#ifdef CONFIG_CIFS_DFS_UPCALL
475 dfs_shrink_umount_helper(vfsmnt);
476#endif /* CONFIG CIFS_DFS_UPCALL */
477
474 if (!(flags & MNT_FORCE)) 478 if (!(flags & MNT_FORCE))
475 return; 479 return;
476 cifs_sb = CIFS_SB(vfsmnt->mnt_sb); 480 cifs_sb = CIFS_SB(vfsmnt->mnt_sb);
diff --git a/fs/cifs/cifsfs.h b/fs/cifs/cifsfs.h
index 2e68126d07eb..195b14de5567 100644
--- a/fs/cifs/cifsfs.h
+++ b/fs/cifs/cifsfs.h
@@ -61,6 +61,10 @@ extern int cifs_setattr(struct dentry *, struct iattr *);
61 61
62extern const struct inode_operations cifs_file_inode_ops; 62extern const struct inode_operations cifs_file_inode_ops;
63extern const struct inode_operations cifs_symlink_inode_ops; 63extern const struct inode_operations cifs_symlink_inode_ops;
64extern struct list_head cifs_dfs_automount_list;
65extern struct inode_operations cifs_dfs_referral_inode_operations;
66
67
64 68
65/* Functions related to files and directories */ 69/* Functions related to files and directories */
66extern const struct file_operations cifs_file_ops; 70extern const struct file_operations cifs_file_ops;
diff --git a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h
index 7093cb4b0212..aaaf748f6a26 100644
--- a/fs/cifs/cifsproto.h
+++ b/fs/cifs/cifsproto.h
@@ -102,6 +102,9 @@ extern int mode_to_acl(struct inode *inode, const char *path, __u64);
102extern int cifs_mount(struct super_block *, struct cifs_sb_info *, char *, 102extern int cifs_mount(struct super_block *, struct cifs_sb_info *, char *,
103 const char *); 103 const char *);
104extern int cifs_umount(struct super_block *, struct cifs_sb_info *); 104extern int cifs_umount(struct super_block *, struct cifs_sb_info *);
105#ifdef CONFIG_CIFS_DFS_UPCALL
106extern void dfs_shrink_umount_helper(struct vfsmount *vfsmnt);
107#endif
105void cifs_proc_init(void); 108void cifs_proc_init(void);
106void cifs_proc_clean(void); 109void cifs_proc_clean(void);
107 110