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 /* BB should we make this contingent on superblock flag NOATIME? */
  81 /*                      old_file->d_inode->i_ctime = CURRENT_TIME;*/
  82                         /* parent dir timestamps will update from srv
  83                         within a second, would it really be worth it
  84                         to set the parent dir cifs inode time to zero
  85                         to force revalidate (faster) for it too? */
  86                 }
  87                 /* if not oplocked will force revalidate to get info
  88                    on source file from srv */
  89                 cifsInode->time = 0;
  90
  91                 /* Will update parent dir timestamps from srv within a second.
  92                    Would it really be worth it to set the parent dir (cifs
  93                    inode) time field to zero to force revalidate on parent
  94                    directory faster ie
  95                         CIFS_I(inode)->time = 0;  */
  96         }
  97
  98 cifs_hl_exit:
  99         kfree(fromName);
 100         kfree(toName);
 101         FreeXid(xid);
 102         return rc;
 103 }
 104
 105 void *
 106 cifs_follow_link(struct dentry *direntry, struct nameidata *nd)
 107 {
 108         struct inode *inode = direntry->d_inode;
 109         int rc = -EACCES;
 110         int xid;
 111         char *full_path = NULL;
 112         char * target_path = ERR_PTR(-ENOMEM);
 113         struct cifs_sb_info *cifs_sb;
 114         struct cifsTconInfo *pTcon;
 115
 116         xid = GetXid();
 117
 118         full_path = build_path_from_dentry(direntry);
 119
 120         if (!full_path)
 121                 goto out_no_free;
 122
 123         cFYI(1, ("Full path: %s inode = 0x%p", full_path, inode));
 124         cifs_sb = CIFS_SB(inode->i_sb);
 125         pTcon = cifs_sb->tcon;
 126         target_path = kmalloc(PATH_MAX, GFP_KERNEL);
 127         if (!target_path) {
 128                 target_path = ERR_PTR(-ENOMEM);
 129                 goto out;
 130         }
 131
 132 /* BB add read reparse point symlink code and Unix extensions symlink code here BB */
 133         if (pTcon->ses->capabilities & CAP_UNIX)
 134                 rc = CIFSSMBUnixQuerySymLink(xid, pTcon, full_path,
 135                                              target_path,
 136                                              PATH_MAX-1,
 137                                              cifs_sb->local_nls);
 138         else {
 139                 /* rc = CIFSSMBQueryReparseLinkInfo */
 140                 /* BB Add code to Query ReparsePoint info */
 141                 /* BB Add MAC style xsymlink check here if enabled */
 142         }
 143
 144         if (rc == 0) {
 145
 146 /* BB Add special case check for Samba DFS symlinks */
 147
 148                 target_path[PATH_MAX-1] = 0;
 149         } else {
 150                 kfree(target_path);
 151                 target_path = ERR_PTR(rc);
 152         }
 153
 154 out:
 155         kfree(full_path);
 156 out_no_free:
 157         FreeXid(xid);
 158         nd_set_link(nd, target_path);
 159         return NULL;    /* No cookie */
 160 }
 161
 162 int
 163 cifs_symlink(struct inode *inode, struct dentry *direntry, const char *symname)
 164 {
 165         int rc = -EOPNOTSUPP;
 166         int xid;
 167         struct cifs_sb_info *cifs_sb;
 168         struct cifsTconInfo *pTcon;
 169         char *full_path = NULL;
 170         struct inode *newinode = NULL;
 171
 172         xid = GetXid();
 173
 174         cifs_sb = CIFS_SB(inode->i_sb);
 175         pTcon = cifs_sb->tcon;
 176
 177         full_path = build_path_from_dentry(direntry);
 178
 179         if(full_path == NULL) {
 180                 FreeXid(xid);
 181                 return -ENOMEM;
 182         }
 183
 184         cFYI(1, ("Full path: %s", full_path));
 185         cFYI(1, ("symname is %s", symname));
 186
 187         /* BB what if DFS and this volume is on different share? BB */
 188         if (cifs_sb->tcon->ses->capabilities & CAP_UNIX)
 189                 rc = CIFSUnixCreateSymLink(xid, pTcon, full_path, symname,
 190                                            cifs_sb->local_nls);
 191         /* else
 192            rc = CIFSCreateReparseSymLink(xid, pTcon, fromName, toName,cifs_sb_target->local_nls); */
 193
 194         if (rc == 0) {
 195                 if (pTcon->ses->capabilities & CAP_UNIX)
 196                         rc = cifs_get_inode_info_unix(&newinode, full_path,
 197                                                       inode->i_sb,xid);
 198                 else
 199                         rc = cifs_get_inode_info(&newinode, full_path, NULL,
 200                                                  inode->i_sb,xid);
 201
 202                 if (rc != 0) {
 203                         cFYI(1, ("Create symlink ok, getinodeinfo fail rc = %d",
 204                               rc));
 205                 } else {
 206                         if (pTcon->nocase)
 207                                 direntry->d_op = &cifs_ci_dentry_ops;
 208                         else
 209                                 direntry->d_op = &cifs_dentry_ops;
 210                         d_instantiate(direntry, newinode);
 211                 }
 212         }
 213
 214         kfree(full_path);
 215         FreeXid(xid);
 216         return rc;
 217 }
 218
 219 int
 220 cifs_readlink(struct dentry *direntry, char __user *pBuffer, int buflen)
 221 {
 222         struct inode *inode = direntry->d_inode;
 223         int rc = -EACCES;
 224         int xid;
 225         int oplock = FALSE;
 226         struct cifs_sb_info *cifs_sb;
 227         struct cifsTconInfo *pTcon;
 228         char *full_path = NULL;
 229         char *tmp_path =  NULL;
 230         char * tmpbuffer;
 231         unsigned char * referrals = NULL;
 232         int num_referrals = 0;
 233         int len;
 234         __u16 fid;
 235
 236         xid = GetXid();
 237         cifs_sb = CIFS_SB(inode->i_sb);
 238         pTcon = cifs_sb->tcon;
 239
 240 /* BB would it be safe against deadlock to grab this sem
 241       even though rename itself grabs the sem and calls lookup? */
 242 /*       mutex_lock(&inode->i_sb->s_vfs_rename_mutex);*/
 243         full_path = build_path_from_dentry(direntry);
 244 /*       mutex_unlock(&inode->i_sb->s_vfs_rename_mutex);*/
 245
 246         if(full_path == NULL) {
 247                 FreeXid(xid);
 248                 return -ENOMEM;
 249         }
 250
 251         cFYI(1,
 252              ("Full path: %s inode = 0x%p pBuffer = 0x%p buflen = %d",
 253               full_path, inode, pBuffer, buflen));
 254         if(buflen > PATH_MAX)
 255                 len = PATH_MAX;
 256         else
 257                 len = buflen;
 258         tmpbuffer = kmalloc(len,GFP_KERNEL);
 259         if(tmpbuffer == NULL) {
 260                 kfree(full_path);
 261                 FreeXid(xid);
 262                 return -ENOMEM;
 263         }
 264
 265 /* BB add read reparse point symlink code and Unix extensions symlink code here BB */
 266         if (cifs_sb->tcon->ses->capabilities & CAP_UNIX)
 267                 rc = CIFSSMBUnixQuerySymLink(xid, pTcon, full_path,
 268                                 tmpbuffer,
 269                                 len - 1,
 270                                 cifs_sb->local_nls);
 271         else if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_UNX_EMUL) {
 272                 cERROR(1,("SFU style symlinks not implemented yet"));
 273                 /* add open and read as in fs/cifs/inode.c */
 274
 275         } else {
 276                 rc = CIFSSMBOpen(xid, pTcon, full_path, FILE_OPEN, GENERIC_READ,
 277                                 OPEN_REPARSE_POINT,&fid, &oplock, NULL,
 278                                 cifs_sb->local_nls,
 279                                 cifs_sb->mnt_cifs_flags &
 280                                         CIFS_MOUNT_MAP_SPECIAL_CHR);
 281                 if(!rc) {
 282                         rc = CIFSSMBQueryReparseLinkInfo(xid, pTcon, full_path,
 283                                 tmpbuffer,
 284                                 len - 1,
 285                                 fid,
 286                                 cifs_sb->local_nls);
 287                         if(CIFSSMBClose(xid, pTcon, fid)) {
 288                                 cFYI(1,("Error closing junction point (open for ioctl)"));
 289                         }
 290                         if(rc == -EIO) {
 291                                 /* Query if DFS Junction */
 292                                 tmp_path =
 293                                         kmalloc(MAX_TREE_SIZE + MAX_PATHCONF + 1,
 294                                                 GFP_KERNEL);
 295                                 if (tmp_path) {
 296                                         strncpy(tmp_path, pTcon->treeName, MAX_TREE_SIZE);
 297                                         strncat(tmp_path, full_path, MAX_PATHCONF);
 298                                         rc = get_dfs_path(xid, pTcon->ses, tmp_path,
 299                                                 cifs_sb->local_nls,
 300                                                 &num_referrals, &referrals,
 301                                                 cifs_sb->mnt_cifs_flags &
 302                                                     CIFS_MOUNT_MAP_SPECIAL_CHR);
 303                                         cFYI(1,("Get DFS for %s rc = %d ",tmp_path, rc));
 304                                         if((num_referrals == 0) && (rc == 0))
 305                                                 rc = -EACCES;
 306                                         else {
 307                                                 cFYI(1,("num referral: %d",num_referrals));
 308                                                 if(referrals) {
 309                                                         cFYI(1,("referral string: %s",referrals));
 310                                                         strncpy(tmpbuffer, referrals, len-1);
 311                                                 }
 312                                         }
 313                                         kfree(referrals);
 314                                         kfree(tmp_path);
 315 }
 316                                 /* BB add code like else decode referrals then memcpy to
 317                                   tmpbuffer and free referrals string array BB */
 318                         }
 319                 }
 320         }
 321         /* BB Anything else to do to handle recursive links? */
 322         /* BB Should we be using page ops here? */
 323
 324         /* BB null terminate returned string in pBuffer? BB */
 325         if (rc == 0) {
 326                 rc = vfs_readlink(direntry, pBuffer, len, tmpbuffer);
 327                 cFYI(1,
 328                      ("vfs_readlink called from cifs_readlink returned %d",
 329                       rc));
 330         }
 331
 332         kfree(tmpbuffer);
 333         kfree(full_path);
 334         FreeXid(xid);
 335         return rc;
 336 }
 337
 338 void cifs_put_link(struct dentry *direntry, struct nameidata *nd, void *cookie)
 339 {
 340         char *p = nd_get_link(nd);
 341         if (!IS_ERR(p))
 342                 kfree(p);
 343 }