1 /*
2 * fs/cifs/link.c
3 *
4 * Copyright (C) International Business Machines Corp., 2002,2008
5 * Author(s): Steve French (sfrench@us.ibm.com)
6 *
7 * This library is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU Lesser General Public License as published
9 * by the Free Software Foundation; either version 2.1 of the License, or
10 * (at your option) any later version.
11 *
12 * This library is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
15 * the GNU Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public License
18 * along with this library; if not, write to the Free Software
19 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20 */
21 #include <linux/fs.h>
22 #include <linux/stat.h>
23 #include <linux/namei.h>
24 #include "cifsfs.h"
25 #include "cifspdu.h"
26 #include "cifsglob.h"
27 #include "cifsproto.h"
28 #include "cifs_debug.h"
29 #include "cifs_fs_sb.h"
30
31 int
cifs_hardlink(struct dentry * old_file,struct inode * inode,struct dentry * direntry)32 cifs_hardlink(struct dentry *old_file, struct inode *inode,
33 struct dentry *direntry)
34 {
35 int rc = -EACCES;
36 int xid;
37 char *fromName = NULL;
38 char *toName = NULL;
39 struct cifs_sb_info *cifs_sb_target;
40 struct cifsTconInfo *pTcon;
41 struct cifsInodeInfo *cifsInode;
42
43 xid = GetXid();
44
45 cifs_sb_target = CIFS_SB(inode->i_sb);
46 pTcon = cifs_sb_target->tcon;
47
48 /* No need to check for cross device links since server will do that
49 BB note DFS case in future though (when we may have to check) */
50
51 fromName = build_path_from_dentry(old_file);
52 toName = build_path_from_dentry(direntry);
53 if ((fromName == NULL) || (toName == NULL)) {
54 rc = -ENOMEM;
55 goto cifs_hl_exit;
56 }
57
58 /* if (cifs_sb_target->tcon->ses->capabilities & CAP_UNIX)*/
59 if (pTcon->unix_ext)
60 rc = CIFSUnixCreateHardLink(xid, pTcon, fromName, toName,
61 cifs_sb_target->local_nls,
62 cifs_sb_target->mnt_cifs_flags &
63 CIFS_MOUNT_MAP_SPECIAL_CHR);
64 else {
65 rc = CIFSCreateHardLink(xid, pTcon, fromName, toName,
66 cifs_sb_target->local_nls,
67 cifs_sb_target->mnt_cifs_flags &
68 CIFS_MOUNT_MAP_SPECIAL_CHR);
69 if ((rc == -EIO) || (rc == -EINVAL))
70 rc = -EOPNOTSUPP;
71 }
72
73 d_drop(direntry); /* force new lookup from server of target */
74
75 /* if source file is cached (oplocked) revalidate will not go to server
76 until the file is closed or oplock broken so update nlinks locally */
77 if (old_file->d_inode) {
78 cifsInode = CIFS_I(old_file->d_inode);
79 if (rc == 0) {
80 old_file->d_inode->i_nlink++;
81 /* BB should we make this contingent on superblock flag NOATIME? */
82 /* old_file->d_inode->i_ctime = CURRENT_TIME;*/
83 /* parent dir timestamps will update from srv
84 within a second, would it really be worth it
85 to set the parent dir cifs inode time to zero
86 to force revalidate (faster) for it too? */
87 }
88 /* if not oplocked will force revalidate to get info
89 on source file from srv */
90 cifsInode->time = 0;
91
92 /* Will update parent dir timestamps from srv within a second.
93 Would it really be worth it to set the parent dir (cifs
94 inode) time field to zero to force revalidate on parent
95 directory faster ie
96 CIFS_I(inode)->time = 0; */
97 }
98
99 cifs_hl_exit:
100 kfree(fromName);
101 kfree(toName);
102 FreeXid(xid);
103 return rc;
104 }
105
106 void *
cifs_follow_link(struct dentry * direntry,struct nameidata * nd)107 cifs_follow_link(struct dentry *direntry, struct nameidata *nd)
108 {
109 struct inode *inode = direntry->d_inode;
110 int rc = -EACCES;
111 int xid;
112 char *full_path = NULL;
113 char *target_path = ERR_PTR(-ENOMEM);
114 struct cifs_sb_info *cifs_sb;
115 struct cifsTconInfo *pTcon;
116
117 xid = GetXid();
118
119 full_path = build_path_from_dentry(direntry);
120
121 if (!full_path)
122 goto out_no_free;
123
124 cFYI(1, ("Full path: %s inode = 0x%p", full_path, inode));
125 cifs_sb = CIFS_SB(inode->i_sb);
126 pTcon = cifs_sb->tcon;
127 target_path = kmalloc(PATH_MAX, GFP_KERNEL);
128 if (!target_path) {
129 target_path = ERR_PTR(-ENOMEM);
130 goto out;
131 }
132
133 /* We could change this to:
134 if (pTcon->unix_ext)
135 but there does not seem any point in refusing to
136 get symlink info if we can, even if unix extensions
137 turned off for this mount */
138
139 if (pTcon->ses->capabilities & CAP_UNIX)
140 rc = CIFSSMBUnixQuerySymLink(xid, pTcon, full_path,
141 target_path,
142 PATH_MAX-1,
143 cifs_sb->local_nls);
144 else {
145 /* BB add read reparse point symlink code here */
146 /* rc = CIFSSMBQueryReparseLinkInfo */
147 /* BB Add code to Query ReparsePoint info */
148 /* BB Add MAC style xsymlink check here if enabled */
149 }
150
151 if (rc == 0) {
152
153 /* BB Add special case check for Samba DFS symlinks */
154
155 target_path[PATH_MAX-1] = 0;
156 } else {
157 kfree(target_path);
158 target_path = ERR_PTR(rc);
159 }
160
161 out:
162 kfree(full_path);
163 out_no_free:
164 FreeXid(xid);
165 nd_set_link(nd, target_path);
166 return NULL; /* No cookie */
167 }
168
169 int
cifs_symlink(struct inode * inode,struct dentry * direntry,const char * symname)170 cifs_symlink(struct inode *inode, struct dentry *direntry, const char *symname)
171 {
172 int rc = -EOPNOTSUPP;
173 int xid;
174 struct cifs_sb_info *cifs_sb;
175 struct cifsTconInfo *pTcon;
176 char *full_path = NULL;
177 struct inode *newinode = NULL;
178
179 xid = GetXid();
180
181 cifs_sb = CIFS_SB(inode->i_sb);
182 pTcon = cifs_sb->tcon;
183
184 full_path = build_path_from_dentry(direntry);
185
186 if (full_path == NULL) {
187 FreeXid(xid);
188 return -ENOMEM;
189 }
190
191 cFYI(1, ("Full path: %s", full_path));
192 cFYI(1, ("symname is %s", symname));
193
194 /* BB what if DFS and this volume is on different share? BB */
195 if (pTcon->unix_ext)
196 rc = CIFSUnixCreateSymLink(xid, pTcon, full_path, symname,
197 cifs_sb->local_nls);
198 /* else
199 rc = CIFSCreateReparseSymLink(xid, pTcon, fromName, toName,
200 cifs_sb_target->local_nls); */
201
202 if (rc == 0) {
203 if (pTcon->unix_ext)
204 rc = cifs_get_inode_info_unix(&newinode, full_path,
205 inode->i_sb, xid);
206 else
207 rc = cifs_get_inode_info(&newinode, full_path, NULL,
208 inode->i_sb, xid, NULL);
209
210 if (rc != 0) {
211 cFYI(1, ("Create symlink ok, getinodeinfo fail rc = %d",
212 rc));
213 } else {
214 if (pTcon->nocase)
215 direntry->d_op = &cifs_ci_dentry_ops;
216 else
217 direntry->d_op = &cifs_dentry_ops;
218 d_instantiate(direntry, newinode);
219 }
220 }
221
222 kfree(full_path);
223 FreeXid(xid);
224 return rc;
225 }
226
227 int
cifs_readlink(struct dentry * direntry,char __user * pBuffer,int buflen)228 cifs_readlink(struct dentry *direntry, char __user *pBuffer, int buflen)
229 {
230 struct inode *inode = direntry->d_inode;
231 int rc = -EACCES;
232 int xid;
233 int oplock = 0;
234 struct cifs_sb_info *cifs_sb;
235 struct cifsTconInfo *pTcon;
236 char *full_path = NULL;
237 char *tmpbuffer;
238 int len;
239 __u16 fid;
240
241 xid = GetXid();
242 cifs_sb = CIFS_SB(inode->i_sb);
243 pTcon = cifs_sb->tcon;
244
245 /* BB would it be safe against deadlock to grab this sem
246 even though rename itself grabs the sem and calls lookup? */
247 /* mutex_lock(&inode->i_sb->s_vfs_rename_mutex);*/
248 full_path = build_path_from_dentry(direntry);
249 /* mutex_unlock(&inode->i_sb->s_vfs_rename_mutex);*/
250
251 if (full_path == NULL) {
252 FreeXid(xid);
253 return -ENOMEM;
254 }
255
256 cFYI(1,
257 ("Full path: %s inode = 0x%p pBuffer = 0x%p buflen = %d",
258 full_path, inode, pBuffer, buflen));
259 if (buflen > PATH_MAX)
260 len = PATH_MAX;
261 else
262 len = buflen;
263 tmpbuffer = kmalloc(len, GFP_KERNEL);
264 if (tmpbuffer == NULL) {
265 kfree(full_path);
266 FreeXid(xid);
267 return -ENOMEM;
268 }
269
270 /* BB add read reparse point symlink code and
271 Unix extensions symlink code here BB */
272 /* We could disable this based on pTcon->unix_ext flag instead ... but why? */
273 if (cifs_sb->tcon->ses->capabilities & CAP_UNIX)
274 rc = CIFSSMBUnixQuerySymLink(xid, pTcon, full_path,
275 tmpbuffer,
276 len - 1,
277 cifs_sb->local_nls);
278 else if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_UNX_EMUL) {
279 cERROR(1, ("SFU style symlinks not implemented yet"));
280 /* add open and read as in fs/cifs/inode.c */
281 } else {
282 rc = CIFSSMBOpen(xid, pTcon, full_path, FILE_OPEN, GENERIC_READ,
283 OPEN_REPARSE_POINT, &fid, &oplock, NULL,
284 cifs_sb->local_nls,
285 cifs_sb->mnt_cifs_flags &
286 CIFS_MOUNT_MAP_SPECIAL_CHR);
287 if (!rc) {
288 rc = CIFSSMBQueryReparseLinkInfo(xid, pTcon, full_path,
289 tmpbuffer,
290 len - 1,
291 fid,
292 cifs_sb->local_nls);
293 if (CIFSSMBClose(xid, pTcon, fid)) {
294 cFYI(1, ("Error closing junction point "
295 "(open for ioctl)"));
296 }
297 /* If it is a DFS junction earlier we would have gotten
298 PATH_NOT_COVERED returned from server so we do
299 not need to request the DFS info here */
300 }
301 }
302 /* BB Anything else to do to handle recursive links? */
303 /* BB Should we be using page ops here? */
304
305 /* BB null terminate returned string in pBuffer? BB */
306 if (rc == 0) {
307 rc = vfs_readlink(direntry, pBuffer, len, tmpbuffer);
308 cFYI(1,
309 ("vfs_readlink called from cifs_readlink returned %d",
310 rc));
311 }
312
313 kfree(tmpbuffer);
314 kfree(full_path);
315 FreeXid(xid);
316 return rc;
317 }
318
cifs_put_link(struct dentry * direntry,struct nameidata * nd,void * cookie)319 void cifs_put_link(struct dentry *direntry, struct nameidata *nd, void *cookie)
320 {
321 char *p = nd_get_link(nd);
322 if (!IS_ERR(p))
323 kfree(p);
324 }
325