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_no_free;
 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         target_path = kmalloc(PATH_MAX, GFP_KERNEL);
 128         if (!target_path) {
 129                 target_path = ERR_PTR(-ENOMEM);
 130                 goto out;
 131         }
 132
 133         /* We could change this to:
 134                 if (pTcon->unix_ext)
 135            but there does not seem any point in refusing to
 136            get symlink info if we can, even if unix extensions
 137            turned off for this mount */
 138
 139         if (pTcon->ses->capabilities & CAP_UNIX)
 140                 rc = CIFSSMBUnixQuerySymLink(xid, pTcon, full_path,
 141                                              target_path,
 142                                              PATH_MAX-1,
 143                                              cifs_sb->local_nls);
 144         else {
 145                 /* BB add read reparse point symlink code here */
 146                 /* rc = CIFSSMBQueryReparseLinkInfo */
 147                 /* BB Add code to Query ReparsePoint info */
 148                 /* BB Add MAC style xsymlink check here if enabled */
 149         }
 150
 151         if (rc == 0) {
 152
 153 /* BB Add special case check for Samba DFS symlinks */
 154
 155                 target_path[PATH_MAX-1] = 0;
 156         } else {
 157                 kfree(target_path);
 158                 target_path = ERR_PTR(rc);
 159         }
 160
 161 out:
 162         kfree(full_path);
 163 out_no_free:
 164         FreeXid(xid);
 165         nd_set_link(nd, target_path);
 166         return NULL;    /* No cookie */
 167 }
 168
 169 int
 170 cifs_symlink(struct inode *inode, struct dentry *direntry, const char *symname)
 171 {
 172         int rc = -EOPNOTSUPP;
 173         int xid;
 174         struct cifs_sb_info *cifs_sb;
 175         struct cifsTconInfo *pTcon;
 176         char *full_path = NULL;
 177         struct inode *newinode = NULL;
 178
 179         xid = GetXid();
 180
 181         cifs_sb = CIFS_SB(inode->i_sb);
 182         pTcon = cifs_sb->tcon;
 183
 184         full_path = build_path_from_dentry(direntry);
 185
 186         if (full_path == NULL) {
 187                 FreeXid(xid);
 188                 return -ENOMEM;
 189         }
 190
 191         cFYI(1, ("Full path: %s", full_path));
 192         cFYI(1, ("symname is %s", symname));
 193
 194         /* BB what if DFS and this volume is on different share? BB */
 195         if (pTcon->unix_ext)
 196                 rc = CIFSUnixCreateSymLink(xid, pTcon, full_path, symname,
 197                                            cifs_sb->local_nls);
 198         /* else
 199            rc = CIFSCreateReparseSymLink(xid, pTcon, fromName, toName,
 200                                         cifs_sb_target->local_nls); */
 201
 202         if (rc == 0) {
 203                 if (pTcon->unix_ext)
 204                         rc = cifs_get_inode_info_unix(&newinode, full_path,
 205                                                       inode->i_sb, xid);
 206                 else
 207                         rc = cifs_get_inode_info(&newinode, full_path, NULL,
 208                                                  inode->i_sb, xid, NULL);
 209
 210                 if (rc != 0) {
 211                         cFYI(1, ("Create symlink ok, getinodeinfo fail rc = %d",
 212                               rc));
 213                 } else {
 214                         if (pTcon->nocase)
 215                                 direntry->d_op = &cifs_ci_dentry_ops;
 216                         else
 217                                 direntry->d_op = &cifs_dentry_ops;
 218                         d_instantiate(direntry, newinode);
 219                 }
 220         }
 221
 222         kfree(full_path);
 223         FreeXid(xid);
 224         return rc;
 225 }
 226
 227 int
 228 cifs_readlink(struct dentry *direntry, char __user *pBuffer, int buflen)
 229 {
 230         struct inode *inode = direntry->d_inode;
 231         int rc = -EACCES;
 232         int xid;
 233         int oplock = FALSE;
 234         struct cifs_sb_info *cifs_sb;
 235         struct cifsTconInfo *pTcon;
 236         char *full_path = NULL;
 237         char *tmp_path = NULL;
 238         char *tmpbuffer;
 239         int len;
 240         __u16 fid;
 241
 242         xid = GetXid();
 243         cifs_sb = CIFS_SB(inode->i_sb);
 244         pTcon = cifs_sb->tcon;
 245
 246 /* BB would it be safe against deadlock to grab this sem
 247       even though rename itself grabs the sem and calls lookup? */
 248 /*       mutex_lock(&inode->i_sb->s_vfs_rename_mutex);*/
 249         full_path = build_path_from_dentry(direntry);
 250 /*       mutex_unlock(&inode->i_sb->s_vfs_rename_mutex);*/
 251
 252         if (full_path == NULL) {
 253                 FreeXid(xid);
 254                 return -ENOMEM;
 255         }
 256
 257         cFYI(1,
 258              ("Full path: %s inode = 0x%p pBuffer = 0x%p buflen = %d",
 259               full_path, inode, pBuffer, buflen));
 260         if (buflen > PATH_MAX)
 261                 len = PATH_MAX;
 262         else
 263                 len = buflen;
 264         tmpbuffer = kmalloc(len, GFP_KERNEL);
 265         if (tmpbuffer == NULL) {
 266                 kfree(full_path);
 267                 FreeXid(xid);
 268                 return -ENOMEM;
 269         }
 270
 271 /* BB add read reparse point symlink code and
 272         Unix extensions symlink code here BB */
 273 /* We could disable this based on pTcon->unix_ext flag instead ... but why? */
 274         if (cifs_sb->tcon->ses->capabilities & CAP_UNIX)
 275                 rc = CIFSSMBUnixQuerySymLink(xid, pTcon, full_path,
 276                                 tmpbuffer,
 277                                 len - 1,
 278                                 cifs_sb->local_nls);
 279         else if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_UNX_EMUL) {
 280                 cERROR(1, ("SFU style symlinks not implemented yet"));
 281                 /* add open and read as in fs/cifs/inode.c */
 282         } else {
 283                 rc = CIFSSMBOpen(xid, pTcon, full_path, FILE_OPEN, GENERIC_READ,
 284                                 OPEN_REPARSE_POINT, &fid, &oplock, NULL,
 285                                 cifs_sb->local_nls,
 286                                 cifs_sb->mnt_cifs_flags &
 287                                         CIFS_MOUNT_MAP_SPECIAL_CHR);
 288                 if (!rc) {
 289                         rc = CIFSSMBQueryReparseLinkInfo(xid, pTcon, full_path,
 290                                 tmpbuffer,
 291                                 len - 1,
 292                                 fid,
 293                                 cifs_sb->local_nls);
 294                         if (CIFSSMBClose(xid, pTcon, fid)) {
 295                                 cFYI(1, ("Error closing junction point "
 296                                          "(open for ioctl)"));
 297                         }
 298                         /* BB unwind this long, nested function, or remove BB */
 299                         if (rc == -EIO) {
 300                                 /* Query if DFS Junction */
 301                                 unsigned int num_referrals = 0;
 302                                 struct dfs_info3_param *refs = NULL;
 303                                 tmp_path =
 304                                         kmalloc(MAX_TREE_SIZE + MAX_PATHCONF + 1,
 305                                                 GFP_KERNEL);
 306                                 if (tmp_path) {
 307                                         strncpy(tmp_path, pTcon->treeName,
 308                                                 MAX_TREE_SIZE);
 309                                         strncat(tmp_path, full_path,
 310                                                 MAX_PATHCONF);
 311                                         rc = get_dfs_path(xid, pTcon->ses,
 312                                                 tmp_path,
 313                                                 cifs_sb->local_nls,
 314                                                 &num_referrals, &refs,
 315                                                 cifs_sb->mnt_cifs_flags &
 316                                                     CIFS_MOUNT_MAP_SPECIAL_CHR);
 317                                         cFYI(1, ("Get DFS for %s rc = %d ",
 318                                                 tmp_path, rc));
 319                                         if ((num_referrals == 0) && (rc == 0))
 320                                                 rc = -EACCES;
 321                                         else {
 322                                                 cFYI(1, ("num referral: %d",
 323                                                         num_referrals));
 324                                                 if (refs && refs->path_name) {
 325                                                         strncpy(tmpbuffer,
 326                                                                 refs->path_name,
 327                                                                 len-1);
 328                                                 }
 329                                         }
 330                                         kfree(refs);
 331                                         kfree(tmp_path);
 332 }
 333                                 /* BB add code like else decode referrals
 334                                 then memcpy to tmpbuffer and free referrals
 335                                 string array BB */
 336                         }
 337                 }
 338         }
 339         /* BB Anything else to do to handle recursive links? */
 340         /* BB Should we be using page ops here? */
 341
 342         /* BB null terminate returned string in pBuffer? BB */
 343         if (rc == 0) {
 344                 rc = vfs_readlink(direntry, pBuffer, len, tmpbuffer);
 345                 cFYI(1,
 346                      ("vfs_readlink called from cifs_readlink returned %d",
 347                       rc));
 348         }
 349
 350         kfree(tmpbuffer);
 351         kfree(full_path);
 352         FreeXid(xid);
 353         return rc;
 354 }
 355
 356 void cifs_put_link(struct dentry *direntry, struct nameidata *nd, void *cookie)
 357 {
 358         char *p = nd_get_link(nd);
 359         if (!IS_ERR(p))
 360                 kfree(p);
 361 }