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 = -ENOMEM;
 111         int xid;
 112         char *full_path = NULL;
 113         char *target_path = NULL;
 114         struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
 115         struct cifsTconInfo *tcon = cifs_sb->tcon;
 116
 117         xid = GetXid();
 118
 119         /*
 120          * For now, we just handle symlinks with unix extensions enabled.
 121          * Eventually we should handle NTFS reparse points, and MacOS
 122          * symlink support. For instance...
 123          *
 124          * rc = CIFSSMBQueryReparseLinkInfo(...)
 125          *
 126          * For now, just return -EACCES when the server doesn't support posix
 127          * extensions. Note that we still allow querying symlinks when posix
 128          * extensions are manually disabled. We could disable these as well
 129          * but there doesn't seem to be any harm in allowing the client to
 130          * read them.
 131          */
 132         if (!(tcon->ses->capabilities & CAP_UNIX)) {
 133                 rc = -EACCES;
 134                 goto out;
 135         }
 136
 137         full_path = build_path_from_dentry(direntry);
 138         if (!full_path)
 139                 goto out;
 140
 141         cFYI(1, ("Full path: %s inode = 0x%p", full_path, inode));
 142
 143         rc = CIFSSMBUnixQuerySymLink(xid, tcon, full_path, &target_path,
 144                                      cifs_sb->local_nls);
 145         kfree(full_path);
 146 out:
 147         if (rc != 0) {
 148                 kfree(target_path);
 149                 target_path = ERR_PTR(rc);
 150         }
 151
 152         FreeXid(xid);
 153         nd_set_link(nd, target_path);
 154         return NULL;
 155 }
 156
 157 int
 158 cifs_symlink(struct inode *inode, struct dentry *direntry, const char *symname)
 159 {
 160         int rc = -EOPNOTSUPP;
 161         int xid;
 162         struct cifs_sb_info *cifs_sb;
 163         struct cifsTconInfo *pTcon;
 164         char *full_path = NULL;
 165         struct inode *newinode = NULL;
 166
 167         xid = GetXid();
 168
 169         cifs_sb = CIFS_SB(inode->i_sb);
 170         pTcon = cifs_sb->tcon;
 171
 172         full_path = build_path_from_dentry(direntry);
 173
 174         if (full_path == NULL) {
 175                 rc = -ENOMEM;
 176                 FreeXid(xid);
 177                 return rc;
 178         }
 179
 180         cFYI(1, ("Full path: %s", full_path));
 181         cFYI(1, ("symname is %s", symname));
 182
 183         /* BB what if DFS and this volume is on different share? BB */
 184         if (pTcon->unix_ext)
 185                 rc = CIFSUnixCreateSymLink(xid, pTcon, full_path, symname,
 186                                            cifs_sb->local_nls);
 187         /* else
 188            rc = CIFSCreateReparseSymLink(xid, pTcon, fromName, toName,
 189                                         cifs_sb_target->local_nls); */
 190
 191         if (rc == 0) {
 192                 if (pTcon->unix_ext)
 193                         rc = cifs_get_inode_info_unix(&newinode, full_path,
 194                                                       inode->i_sb, xid);
 195                 else
 196                         rc = cifs_get_inode_info(&newinode, full_path, NULL,
 197                                                  inode->i_sb, xid, NULL);
 198
 199                 if (rc != 0) {
 200                         cFYI(1, ("Create symlink ok, getinodeinfo fail rc = %d",
 201                               rc));
 202                 } else {
 203                         if (pTcon->nocase)
 204                                 direntry->d_op = &cifs_ci_dentry_ops;
 205                         else
 206                                 direntry->d_op = &cifs_dentry_ops;
 207                         d_instantiate(direntry, newinode);
 208                 }
 209         }
 210
 211         kfree(full_path);
 212         FreeXid(xid);
 213         return rc;
 214 }
 215
 216 void cifs_put_link(struct dentry *direntry, struct nameidata *nd, void *cookie)
 217 {
 218         char *p = nd_get_link(nd);
 219         if (!IS_ERR(p))
 220                 kfree(p);
 221 }