fs/cifs/link.c

   1 /*
   2  *   fs/cifs/link.c
   3  *
   4  *   Copyright (C) International Business Machines  Corp., 2002,2003
   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                 rc = CIFSUnixCreateHardLink(xid, pTcon, fromName, toName,
  60                                             cifs_sb_target->local_nls,
  61                                             cifs_sb_target->mnt_cifs_flags &
  62                                                 CIFS_MOUNT_MAP_SPECIAL_CHR);
  63         else {
  64                 rc = CIFSCreateHardLink(xid, pTcon, fromName, toName,
  65                                         cifs_sb_target->local_nls,
  66                                         cifs_sb_target->mnt_cifs_flags &
  67                                                 CIFS_MOUNT_MAP_SPECIAL_CHR);
  68                 if((rc == -EIO) || (rc == -EINVAL))
  69                         rc = -EOPNOTSUPP;
  70         }
  71
  72         d_drop(direntry);       /* force new lookup from server of target */
  73
  74         /* if source file is cached (oplocked) revalidate will not go to server
  75            until the file is closed or oplock broken so update nlinks locally */
  76         if(old_file->d_inode) {
  77                 cifsInode = CIFS_I(old_file->d_inode);
  78                 if(rc == 0) {
  79                         old_file->d_inode->i_nlink++;
  80                         old_file->d_inode->i_ctime = CURRENT_TIME;
  81                         /* parent dir timestamps will update from srv
  82                         within a second, would it really be worth it
  83                         to set the parent dir cifs inode time to zero
  84                         to force revalidate (faster) for it too? */
  85                 }
  86                 /* if not oplocked will force revalidate to get info
  87                    on source file from srv */
  88                 cifsInode->time = 0;
  89
  90                 /* Will update parent dir timestamps from srv within a second.
  91                    Would it really be worth it to set the parent dir (cifs
  92                    inode) time field to zero to force revalidate on parent
  93                    directory faster ie
  94                         CIFS_I(inode)->time = 0;  */
  95         }
  96
  97 cifs_hl_exit:
  98         kfree(fromName);
  99         kfree(toName);
 100         FreeXid(xid);
 101         return rc;
 102 }
 103
 104 void *
 105 cifs_follow_link(struct dentry *direntry, struct nameidata *nd)
 106 {
 107         struct inode *inode = direntry->d_inode;
 108         int rc = -EACCES;
 109         int xid;
 110         char *full_path = NULL;
 111         char * target_path = ERR_PTR(-ENOMEM);
 112         struct cifs_sb_info *cifs_sb;
 113         struct cifsTconInfo *pTcon;
 114
 115         xid = GetXid();
 116
 117         full_path = build_path_from_dentry(direntry);
 118
 119         if (!full_path)
 120                 goto out_no_free;
 121
 122         cFYI(1, ("Full path: %s inode = 0x%p", full_path, inode));
 123         cifs_sb = CIFS_SB(inode->i_sb);
 124         pTcon = cifs_sb->tcon;
 125         target_path = kmalloc(PATH_MAX, GFP_KERNEL);
 126         if (!target_path) {
 127                 target_path = ERR_PTR(-ENOMEM);
 128                 goto out;
 129         }
 130
 131 /* BB add read reparse point symlink code and Unix extensions symlink code here BB */
 132         if (pTcon->ses->capabilities & CAP_UNIX)
 133                 rc = CIFSSMBUnixQuerySymLink(xid, pTcon, full_path,
 134                                              target_path,
 135                                              PATH_MAX-1,
 136                                              cifs_sb->local_nls);
 137         else {
 138                 /* rc = CIFSSMBQueryReparseLinkInfo */
 139                 /* BB Add code to Query ReparsePoint info */
 140                 /* BB Add MAC style xsymlink check here if enabled */
 141         }
 142
 143         if (rc == 0) {
 144
 145 /* BB Add special case check for Samba DFS symlinks */
 146
 147                 target_path[PATH_MAX-1] = 0;
 148         } else {
 149                 kfree(target_path);
 150                 target_path = ERR_PTR(rc);
 151         }
 152
 153 out:
 154         kfree(full_path);
 155 out_no_free:
 156         FreeXid(xid);
 157         nd_set_link(nd, target_path);
 158         return NULL;    /* No cookie */
 159 }
 160
 161 int
 162 cifs_symlink(struct inode *inode, struct dentry *direntry, const char *symname)
 163 {
 164         int rc = -EOPNOTSUPP;
 165         int xid;
 166         struct cifs_sb_info *cifs_sb;
 167         struct cifsTconInfo *pTcon;
 168         char *full_path = NULL;
 169         struct inode *newinode = NULL;
 170
 171         xid = GetXid();
 172
 173         cifs_sb = CIFS_SB(inode->i_sb);
 174         pTcon = cifs_sb->tcon;
 175
 176         full_path = build_path_from_dentry(direntry);
 177
 178         if(full_path == NULL) {
 179                 FreeXid(xid);
 180                 return -ENOMEM;
 181         }
 182
 183         cFYI(1, ("Full path: %s", full_path));
 184         cFYI(1, ("symname is %s", symname));
 185
 186         /* BB what if DFS and this volume is on different share? BB */
 187         if (cifs_sb->tcon->ses->capabilities & CAP_UNIX)
 188                 rc = CIFSUnixCreateSymLink(xid, pTcon, full_path, symname,
 189                                            cifs_sb->local_nls);
 190         /* else
 191            rc = CIFSCreateReparseSymLink(xid, pTcon, fromName, toName,cifs_sb_target->local_nls); */
 192
 193         if (rc == 0) {
 194                 if (pTcon->ses->capabilities & CAP_UNIX)
 195                         rc = cifs_get_inode_info_unix(&newinode, full_path,
 196                                                       inode->i_sb,xid);
 197                 else
 198                         rc = cifs_get_inode_info(&newinode, full_path, NULL,
 199                                                  inode->i_sb,xid);
 200
 201                 if (rc != 0) {
 202                         cFYI(1, ("Create symlink ok, getinodeinfo fail rc = %d",
 203                               rc));
 204                 } else {
 205                         if (pTcon->nocase)
 206                                 direntry->d_op = &cifs_ci_dentry_ops;
 207                         else
 208                                 direntry->d_op = &cifs_dentry_ops;
 209                         d_instantiate(direntry, newinode);
 210                 }
 211         }
 212
 213         kfree(full_path);
 214         FreeXid(xid);
 215         return rc;
 216 }
 217
 218 int
 219 cifs_readlink(struct dentry *direntry, char __user *pBuffer, int buflen)
 220 {
 221         struct inode *inode = direntry->d_inode;
 222         int rc = -EACCES;
 223         int xid;
 224         int oplock = FALSE;
 225         struct cifs_sb_info *cifs_sb;
 226         struct cifsTconInfo *pTcon;
 227         char *full_path = NULL;
 228         char *tmp_path =  NULL;
 229         char * tmpbuffer;
 230         unsigned char * referrals = NULL;
 231         int num_referrals = 0;
 232         int len;
 233         __u16 fid;
 234
 235         xid = GetXid();
 236         cifs_sb = CIFS_SB(inode->i_sb);
 237         pTcon = cifs_sb->tcon;
 238
 239 /* BB would it be safe against deadlock to grab this sem
 240       even though rename itself grabs the sem and calls lookup? */
 241 /*       mutex_lock(&inode->i_sb->s_vfs_rename_mutex);*/
 242         full_path = build_path_from_dentry(direntry);
 243 /*       mutex_unlock(&inode->i_sb->s_vfs_rename_mutex);*/
 244
 245         if(full_path == NULL) {
 246                 FreeXid(xid);
 247                 return -ENOMEM;
 248         }
 249
 250         cFYI(1,
 251              ("Full path: %s inode = 0x%p pBuffer = 0x%p buflen = %d",
 252               full_path, inode, pBuffer, buflen));
 253         if(buflen > PATH_MAX)
 254                 len = PATH_MAX;
 255         else
 256                 len = buflen;
 257         tmpbuffer = kmalloc(len,GFP_KERNEL);
 258         if(tmpbuffer == NULL) {
 259                 kfree(full_path);
 260                 FreeXid(xid);
 261                 return -ENOMEM;
 262         }
 263
 264 /* BB add read reparse point symlink code and Unix extensions symlink code here BB */
 265         if (cifs_sb->tcon->ses->capabilities & CAP_UNIX)
 266                 rc = CIFSSMBUnixQuerySymLink(xid, pTcon, full_path,
 267                                 tmpbuffer,
 268                                 len - 1,
 269                                 cifs_sb->local_nls);
 270         else if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_UNX_EMUL) {
 271                 cERROR(1,("SFU style symlinks not implemented yet"));
 272                 /* add open and read as in fs/cifs/inode.c */
 273
 274         } else {
 275                 rc = CIFSSMBOpen(xid, pTcon, full_path, FILE_OPEN, GENERIC_READ,
 276                                 OPEN_REPARSE_POINT,&fid, &oplock, NULL,
 277                                 cifs_sb->local_nls,
 278                                 cifs_sb->mnt_cifs_flags &
 279                                         CIFS_MOUNT_MAP_SPECIAL_CHR);
 280                 if(!rc) {
 281                         rc = CIFSSMBQueryReparseLinkInfo(xid, pTcon, full_path,
 282                                 tmpbuffer,
 283                                 len - 1,
 284                                 fid,
 285                                 cifs_sb->local_nls);
 286                         if(CIFSSMBClose(xid, pTcon, fid)) {
 287                                 cFYI(1,("Error closing junction point (open for ioctl)"));
 288                         }
 289                         if(rc == -EIO) {
 290                                 /* Query if DFS Junction */
 291                                 tmp_path =
 292                                         kmalloc(MAX_TREE_SIZE + MAX_PATHCONF + 1,
 293                                                 GFP_KERNEL);
 294                                 if (tmp_path) {
 295                                         strncpy(tmp_path, pTcon->treeName, MAX_TREE_SIZE);
 296                                         strncat(tmp_path, full_path, MAX_PATHCONF);
 297                                         rc = get_dfs_path(xid, pTcon->ses, tmp_path,
 298                                                 cifs_sb->local_nls,
 299                                                 &num_referrals, &referrals,
 300                                                 cifs_sb->mnt_cifs_flags &
 301                                                     CIFS_MOUNT_MAP_SPECIAL_CHR);
 302                                         cFYI(1,("Get DFS for %s rc = %d ",tmp_path, rc));
 303                                         if((num_referrals == 0) && (rc == 0))
 304                                                 rc = -EACCES;
 305                                         else {
 306                                                 cFYI(1,("num referral: %d",num_referrals));
 307                                                 if(referrals) {
 308                                                         cFYI(1,("referral string: %s",referrals));
 309                                                         strncpy(tmpbuffer, referrals, len-1);
 310                                                 }
 311                                         }
 312                                         kfree(referrals);
 313                                         kfree(tmp_path);
 314 }
 315                                 /* BB add code like else decode referrals then memcpy to
 316                                   tmpbuffer and free referrals string array BB */
 317                         }
 318                 }
 319         }
 320         /* BB Anything else to do to handle recursive links? */
 321         /* BB Should we be using page ops here? */
 322
 323         /* BB null terminate returned string in pBuffer? BB */
 324         if (rc == 0) {
 325                 rc = vfs_readlink(direntry, pBuffer, len, tmpbuffer);
 326                 cFYI(1,
 327                      ("vfs_readlink called from cifs_readlink returned %d",
 328                       rc));
 329         }
 330
 331         kfree(tmpbuffer);
 332         kfree(full_path);
 333         FreeXid(xid);
 334         return rc;
 335 }
 336
 337 void cifs_put_link(struct dentry *direntry, struct nameidata *nd, void *cookie)
 338 {
 339         char *p = nd_get_link(nd);
 340         if (!IS_ERR(p))
 341                 kfree(p);
 342 }