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;
 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
 128         /* We could change this to:
 129                 if (pTcon->unix_ext)
 130            but there does not seem any point in refusing to
 131            get symlink info if we can, even if unix extensions
 132            turned off for this mount */
 133
 134         if (pTcon->ses->capabilities & CAP_UNIX)
 135                 rc = CIFSSMBUnixQuerySymLink(xid, pTcon, full_path,
 136                                              &target_path,
 137                                              cifs_sb->local_nls);
 138         else {
 139                 /* BB add read reparse point symlink code here */
 140                 /* rc = CIFSSMBQueryReparseLinkInfo */
 141                 /* BB Add code to Query ReparsePoint info */
 142                 /* BB Add MAC style xsymlink check here if enabled */
 143         }
 144
 145         if (rc != 0) {
 146                 kfree(target_path);
 147                 target_path = ERR_PTR(rc);
 148         }
 149
 150         kfree(full_path);
 151 out:
 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                 FreeXid(xid);
 176                 return -ENOMEM;
 177         }
 178
 179         cFYI(1, ("Full path: %s", full_path));
 180         cFYI(1, ("symname is %s", symname));
 181
 182         /* BB what if DFS and this volume is on different share? BB */
 183         if (pTcon->unix_ext)
 184                 rc = CIFSUnixCreateSymLink(xid, pTcon, full_path, symname,
 185                                            cifs_sb->local_nls);
 186         /* else
 187            rc = CIFSCreateReparseSymLink(xid, pTcon, fromName, toName,
 188                                         cifs_sb_target->local_nls); */
 189
 190         if (rc == 0) {
 191                 if (pTcon->unix_ext)
 192                         rc = cifs_get_inode_info_unix(&newinode, full_path,
 193                                                       inode->i_sb, xid);
 194                 else
 195                         rc = cifs_get_inode_info(&newinode, full_path, NULL,
 196                                                  inode->i_sb, xid, NULL);
 197
 198                 if (rc != 0) {
 199                         cFYI(1, ("Create symlink ok, getinodeinfo fail rc = %d",
 200                               rc));
 201                 } else {
 202                         if (pTcon->nocase)
 203                                 direntry->d_op = &cifs_ci_dentry_ops;
 204                         else
 205                                 direntry->d_op = &cifs_dentry_ops;
 206                         d_instantiate(direntry, newinode);
 207                 }
 208         }
 209
 210         kfree(full_path);
 211         FreeXid(xid);
 212         return rc;
 213 }
 214
 215 int
 216 cifs_readlink(struct dentry *direntry, char __user *pBuffer, int buflen)
 217 {
 218         struct inode *inode = direntry->d_inode;
 219         int rc = -EACCES;
 220         int xid;
 221         int oplock = 0;
 222         struct cifs_sb_info *cifs_sb;
 223         struct cifsTconInfo *pTcon;
 224         char *full_path = NULL;
 225         char *tmpbuffer;
 226         int len;
 227         __u16 fid;
 228
 229         xid = GetXid();
 230         cifs_sb = CIFS_SB(inode->i_sb);
 231         pTcon = cifs_sb->tcon;
 232
 233 /* BB would it be safe against deadlock to grab this sem
 234       even though rename itself grabs the sem and calls lookup? */
 235 /*       mutex_lock(&inode->i_sb->s_vfs_rename_mutex);*/
 236         full_path = build_path_from_dentry(direntry);
 237 /*       mutex_unlock(&inode->i_sb->s_vfs_rename_mutex);*/
 238
 239         if (full_path == NULL) {
 240                 FreeXid(xid);
 241                 return -ENOMEM;
 242         }
 243
 244         cFYI(1,
 245              ("Full path: %s inode = 0x%p pBuffer = 0x%p buflen = %d",
 246               full_path, inode, pBuffer, buflen));
 247         if (buflen > PATH_MAX)
 248                 len = PATH_MAX;
 249         else
 250                 len = buflen;
 251         tmpbuffer = kmalloc(len, GFP_KERNEL);
 252         if (tmpbuffer == NULL) {
 253                 kfree(full_path);
 254                 FreeXid(xid);
 255                 return -ENOMEM;
 256         }
 257
 258 /* BB add read reparse point symlink code and
 259         Unix extensions symlink code here BB */
 260
 261         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_UNX_EMUL) {
 262                 cERROR(1, ("SFU style symlinks not implemented yet"));
 263                 /* add open and read as in fs/cifs/inode.c */
 264         } else {
 265                 rc = CIFSSMBOpen(xid, pTcon, full_path, FILE_OPEN, GENERIC_READ,
 266                                 OPEN_REPARSE_POINT, &fid, &oplock, NULL,
 267                                 cifs_sb->local_nls,
 268                                 cifs_sb->mnt_cifs_flags &
 269                                         CIFS_MOUNT_MAP_SPECIAL_CHR);
 270                 if (!rc) {
 271                         rc = CIFSSMBQueryReparseLinkInfo(xid, pTcon, full_path,
 272                                 tmpbuffer,
 273                                 len - 1,
 274                                 fid,
 275                                 cifs_sb->local_nls);
 276                         if (CIFSSMBClose(xid, pTcon, fid)) {
 277                                 cFYI(1, ("Error closing junction point "
 278                                          "(open for ioctl)"));
 279                         }
 280                         /* If it is a DFS junction earlier we would have gotten
 281                            PATH_NOT_COVERED returned from server so we do
 282                            not need to request the DFS info here */
 283                 }
 284         }
 285         /* BB Anything else to do to handle recursive links? */
 286         /* BB Should we be using page ops here? */
 287
 288         /* BB null terminate returned string in pBuffer? BB */
 289         if (rc == 0) {
 290                 rc = vfs_readlink(direntry, pBuffer, len, tmpbuffer);
 291                 cFYI(1,
 292                      ("vfs_readlink called from cifs_readlink returned %d",
 293                       rc));
 294         }
 295
 296         kfree(tmpbuffer);
 297         kfree(full_path);
 298         FreeXid(xid);
 299         return rc;
 300 }
 301
 302 void cifs_put_link(struct dentry *direntry, struct nameidata *nd, void *cookie)
 303 {
 304         char *p = nd_get_link(nd);
 305         if (!IS_ERR(p))
 306                 kfree(p);
 307 }