[CIFS] Fix hang in mount when negprot causes server to kill tcp session
[linux-2.6.git] / fs / cifs / link.c
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
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 *
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
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
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
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 }