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
 133            symlink code here BB */
 134         if (pTcon->ses->capabilities & CAP_UNIX)
 135                 rc = CIFSSMBUnixQuerySymLink(xid, pTcon, full_path,
 136                                              target_path,
 137                                              PATH_MAX-1,
 138                                              cifs_sb->local_nls);
 139         else {
 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
 147 /* BB Add special case check for Samba DFS symlinks */
 148
 149                 target_path[PATH_MAX-1] = 0;
 150         } else {
 151                 kfree(target_path);
 152                 target_path = ERR_PTR(rc);
 153         }
 154
 155 out:
 156         kfree(full_path);
 157 out_no_free:
 158         FreeXid(xid);
 159         nd_set_link(nd, target_path);
 160         return NULL;    /* No cookie */
 161 }
 162
 163 int
 164 cifs_symlink(struct inode *inode, struct dentry *direntry, const char *symname)
 165 {
 166         int rc = -EOPNOTSUPP;
 167         int xid;
 168         struct cifs_sb_info *cifs_sb;
 169         struct cifsTconInfo *pTcon;
 170         char *full_path = NULL;
 171         struct inode *newinode = NULL;
 172
 173         xid = GetXid();
 174
 175         cifs_sb = CIFS_SB(inode->i_sb);
 176         pTcon = cifs_sb->tcon;
 177
 178         full_path = build_path_from_dentry(direntry);
 179
 180         if (full_path == NULL) {
 181                 FreeXid(xid);
 182                 return -ENOMEM;
 183         }
 184
 185         cFYI(1, ("Full path: %s", full_path));
 186         cFYI(1, ("symname is %s", symname));
 187
 188         /* BB what if DFS and this volume is on different share? BB */
 189         if (cifs_sb->tcon->ses->capabilities & CAP_UNIX)
 190                 rc = CIFSUnixCreateSymLink(xid, pTcon, full_path, symname,
 191                                            cifs_sb->local_nls);
 192         /* else
 193            rc = CIFSCreateReparseSymLink(xid, pTcon, fromName, toName,
 194                                         cifs_sb_target->local_nls); */
 195
 196         if (rc == 0) {
 197                 if (pTcon->ses->capabilities & CAP_UNIX)
 198                         rc = cifs_get_inode_info_unix(&newinode, full_path,
 199                                                       inode->i_sb, xid);
 200                 else
 201                         rc = cifs_get_inode_info(&newinode, full_path, NULL,
 202                                                  inode->i_sb, xid);
 203
 204                 if (rc != 0) {
 205                         cFYI(1, ("Create symlink ok, getinodeinfo fail rc = %d",
 206                               rc));
 207                 } else {
 208                         if (pTcon->nocase)
 209                                 direntry->d_op = &cifs_ci_dentry_ops;
 210                         else
 211                                 direntry->d_op = &cifs_dentry_ops;
 212                         d_instantiate(direntry, newinode);
 213                 }
 214         }
 215
 216         kfree(full_path);
 217         FreeXid(xid);
 218         return rc;
 219 }
 220
 221 int
 222 cifs_readlink(struct dentry *direntry, char __user *pBuffer, int buflen)
 223 {
 224         struct inode *inode = direntry->d_inode;
 225         int rc = -EACCES;
 226         int xid;
 227         int oplock = FALSE;
 228         struct cifs_sb_info *cifs_sb;
 229         struct cifsTconInfo *pTcon;
 230         char *full_path = NULL;
 231         char *tmp_path = NULL;
 232         char *tmpbuffer;
 233         unsigned char *referrals = NULL;
 234         int num_referrals = 0;
 235         int len;
 236         __u16 fid;
 237
 238         xid = GetXid();
 239         cifs_sb = CIFS_SB(inode->i_sb);
 240         pTcon = cifs_sb->tcon;
 241
 242 /* BB would it be safe against deadlock to grab this sem
 243       even though rename itself grabs the sem and calls lookup? */
 244 /*       mutex_lock(&inode->i_sb->s_vfs_rename_mutex);*/
 245         full_path = build_path_from_dentry(direntry);
 246 /*       mutex_unlock(&inode->i_sb->s_vfs_rename_mutex);*/
 247
 248         if (full_path == NULL) {
 249                 FreeXid(xid);
 250                 return -ENOMEM;
 251         }
 252
 253         cFYI(1,
 254              ("Full path: %s inode = 0x%p pBuffer = 0x%p buflen = %d",
 255               full_path, inode, pBuffer, buflen));
 256         if (buflen > PATH_MAX)
 257                 len = PATH_MAX;
 258         else
 259                 len = buflen;
 260         tmpbuffer = kmalloc(len, GFP_KERNEL);
 261         if (tmpbuffer == NULL) {
 262                 kfree(full_path);
 263                 FreeXid(xid);
 264                 return -ENOMEM;
 265         }
 266
 267 /* BB add read reparse point symlink code and
 268         Unix extensions symlink code here BB */
 269         if (cifs_sb->tcon->ses->capabilities & CAP_UNIX)
 270                 rc = CIFSSMBUnixQuerySymLink(xid, pTcon, full_path,
 271                                 tmpbuffer,
 272                                 len - 1,
 273                                 cifs_sb->local_nls);
 274         else if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_UNX_EMUL) {
 275                 cERROR(1, ("SFU style symlinks not implemented yet"));
 276                 /* add open and read as in fs/cifs/inode.c */
 277         } else {
 278                 rc = CIFSSMBOpen(xid, pTcon, full_path, FILE_OPEN, GENERIC_READ,
 279                                 OPEN_REPARSE_POINT, &fid, &oplock, NULL,
 280                                 cifs_sb->local_nls,
 281                                 cifs_sb->mnt_cifs_flags &
 282                                         CIFS_MOUNT_MAP_SPECIAL_CHR);
 283                 if (!rc) {
 284                         rc = CIFSSMBQueryReparseLinkInfo(xid, pTcon, full_path,
 285                                 tmpbuffer,
 286                                 len - 1,
 287                                 fid,
 288                                 cifs_sb->local_nls);
 289                         if (CIFSSMBClose(xid, pTcon, fid)) {
 290                                 cFYI(1,("Error closing junction point (open for ioctl)"));
 291                         }
 292                         if (rc == -EIO) {
 293                                 /* Query if DFS Junction */
 294                                 tmp_path =
 295                                         kmalloc(MAX_TREE_SIZE + MAX_PATHCONF + 1,
 296                                                 GFP_KERNEL);
 297                                 if (tmp_path) {
 298                                         strncpy(tmp_path, pTcon->treeName,
 299                                                 MAX_TREE_SIZE);
 300                                         strncat(tmp_path, full_path,
 301                                                 MAX_PATHCONF);
 302                                         rc = get_dfs_path(xid, pTcon->ses,
 303                                                 tmp_path,
 304                                                 cifs_sb->local_nls,
 305                                                 &num_referrals, &referrals,
 306                                                 cifs_sb->mnt_cifs_flags &
 307                                                     CIFS_MOUNT_MAP_SPECIAL_CHR);
 308                                         cFYI(1, ("Get DFS for %s rc = %d ",
 309                                                 tmp_path, rc));
 310                                         if ((num_referrals == 0) && (rc == 0))
 311                                                 rc = -EACCES;
 312                                         else {
 313                                                 cFYI(1, ("num referral: %d",
 314                                                         num_referrals));
 315                                                 if (referrals) {
 316                                                         cFYI(1,("referral string: %s", referrals));
 317                                                         strncpy(tmpbuffer,
 318                                                                 referrals,
 319                                                                 len-1);
 320                                                 }
 321                                         }
 322                                         kfree(referrals);
 323                                         kfree(tmp_path);
 324 }
 325                                 /* BB add code like else decode referrals
 326                                 then memcpy to tmpbuffer and free referrals
 327                                 string array BB */
 328                         }
 329                 }
 330         }
 331         /* BB Anything else to do to handle recursive links? */
 332         /* BB Should we be using page ops here? */
 333
 334         /* BB null terminate returned string in pBuffer? BB */
 335         if (rc == 0) {
 336                 rc = vfs_readlink(direntry, pBuffer, len, tmpbuffer);
 337                 cFYI(1,
 338                      ("vfs_readlink called from cifs_readlink returned %d",
 339                       rc));
 340         }
 341
 342         kfree(tmpbuffer);
 343         kfree(full_path);
 344         FreeXid(xid);
 345         return rc;
 346 }
 347
 348 void cifs_put_link(struct dentry *direntry, struct nameidata *nd, void *cookie)
 349 {
 350         char *p = nd_get_link(nd);
 351         if (!IS_ERR(p))
 352                 kfree(p);
 353 }