/*
 *   fs/cifs/link.c
 *
 *   Copyright (C) International Business Machines  Corp., 2002,2008
 *   Author(s): Steve French (sfrench@us.ibm.com)
 *
 *   This library is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU Lesser General Public License as published
 *   by the Free Software Foundation; either version 2.1 of the License, or
 *   (at your option) any later version.
 *
 *   This library is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
 *   the GNU Lesser General Public License for more details.
 *
 *   You should have received a copy of the GNU Lesser General Public License
 *   along with this library; if not, write to the Free Software
 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */
#include <linux/fs.h>
#include <linux/stat.h>
#include <linux/namei.h>
#include "cifsfs.h"
#include "cifspdu.h"
#include "cifsglob.h"
#include "cifsproto.h"
#include "cifs_debug.h"
#include "cifs_fs_sb.h"

int
cifs_hardlink(struct dentry *old_file, struct inode *inode,
              struct dentry *direntry)
{
        int rc = -EACCES;
        int xid;
        char *fromName = NULL;
        char *toName = NULL;
        struct cifs_sb_info *cifs_sb_target;
        struct cifsTconInfo *pTcon;
        struct cifsInodeInfo *cifsInode;

        xid = GetXid();

        cifs_sb_target = CIFS_SB(inode->i_sb);
        pTcon = cifs_sb_target->tcon;

/* No need to check for cross device links since server will do that
   BB note DFS case in future though (when we may have to check) */

        fromName = build_path_from_dentry(old_file);
        toName = build_path_from_dentry(direntry);
        if ((fromName == NULL) || (toName == NULL)) {
                rc = -ENOMEM;
                goto cifs_hl_exit;
        }

/*      if (cifs_sb_target->tcon->ses->capabilities & CAP_UNIX)*/
        if (pTcon->unix_ext)
                rc = CIFSUnixCreateHardLink(xid, pTcon, fromName, toName,
                                            cifs_sb_target->local_nls,
                                            cifs_sb_target->mnt_cifs_flags &
                                                CIFS_MOUNT_MAP_SPECIAL_CHR);
        else {
                rc = CIFSCreateHardLink(xid, pTcon, fromName, toName,
                                        cifs_sb_target->local_nls,
                                        cifs_sb_target->mnt_cifs_flags &
                                                CIFS_MOUNT_MAP_SPECIAL_CHR);
                if ((rc == -EIO) || (rc == -EINVAL))
                        rc = -EOPNOTSUPP;
        }

        d_drop(direntry);       /* force new lookup from server of target */

        /* if source file is cached (oplocked) revalidate will not go to server
           until the file is closed or oplock broken so update nlinks locally */
        if (old_file->d_inode) {
                cifsInode = CIFS_I(old_file->d_inode);
                if (rc == 0) {
                        old_file->d_inode->i_nlink++;
/* BB should we make this contingent on superblock flag NOATIME? */
/*                      old_file->d_inode->i_ctime = CURRENT_TIME;*/
                        /* parent dir timestamps will update from srv
                        within a second, would it really be worth it
                        to set the parent dir cifs inode time to zero
                        to force revalidate (faster) for it too? */
                }
                /* if not oplocked will force revalidate to get info
                   on source file from srv */
                cifsInode->time = 0;

                /* Will update parent dir timestamps from srv within a second.
                   Would it really be worth it to set the parent dir (cifs
                   inode) time field to zero to force revalidate on parent
                   directory faster ie
                        CIFS_I(inode)->time = 0;  */
        }

cifs_hl_exit:
        kfree(fromName);
        kfree(toName);
        FreeXid(xid);
        return rc;
}

void *
cifs_follow_link(struct dentry *direntry, struct nameidata *nd)
{
        struct inode *inode = direntry->d_inode;
        int rc = -ENOMEM;
        int xid;
        char *full_path = NULL;
        char *target_path = NULL;
        struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
        struct cifsTconInfo *tcon = cifs_sb->tcon;

        xid = GetXid();

        /*
         * For now, we just handle symlinks with unix extensions enabled.
         * Eventually we should handle NTFS reparse points, and MacOS
         * symlink support. For instance...
         *
         * rc = CIFSSMBQueryReparseLinkInfo(...)
         *
         * For now, just return -EACCES when the server doesn't support posix
         * extensions. Note that we still allow querying symlinks when posix
         * extensions are manually disabled. We could disable these as well
         * but there doesn't seem to be any harm in allowing the client to
         * read them.
         */
        if (!(tcon->ses->capabilities & CAP_UNIX)) {
                rc = -EACCES;
                goto out;
        }

        full_path = build_path_from_dentry(direntry);
        if (!full_path)
                goto out;

        cFYI(1, ("Full path: %s inode = 0x%p", full_path, inode));

        rc = CIFSSMBUnixQuerySymLink(xid, tcon, full_path, &target_path,
                                     cifs_sb->local_nls);
        kfree(full_path);
out:
        if (rc != 0) {
                kfree(target_path);
                target_path = ERR_PTR(rc);
        }

        FreeXid(xid);
        nd_set_link(nd, target_path);
        return NULL;
}

int
cifs_symlink(struct inode *inode, struct dentry *direntry, const char *symname)
{
        int rc = -EOPNOTSUPP;
        int xid;
        struct cifs_sb_info *cifs_sb;
        struct cifsTconInfo *pTcon;
        char *full_path = NULL;
        struct inode *newinode = NULL;

        xid = GetXid();

        cifs_sb = CIFS_SB(inode->i_sb);
        pTcon = cifs_sb->tcon;

        full_path = build_path_from_dentry(direntry);

        if (full_path == NULL) {
                rc = -ENOMEM;
                FreeXid(xid);
                return rc;
        }

        cFYI(1, ("Full path: %s", full_path));
        cFYI(1, ("symname is %s", symname));

        /* BB what if DFS and this volume is on different share? BB */
        if (pTcon->unix_ext)
                rc = CIFSUnixCreateSymLink(xid, pTcon, full_path, symname,
                                           cifs_sb->local_nls);
        /* else
           rc = CIFSCreateReparseSymLink(xid, pTcon, fromName, toName,
                                        cifs_sb_target->local_nls); */

        if (rc == 0) {
                if (pTcon->unix_ext)
                        rc = cifs_get_inode_info_unix(&newinode, full_path,
                                                      inode->i_sb, xid);
                else
                        rc = cifs_get_inode_info(&newinode, full_path, NULL,
                                                 inode->i_sb, xid, NULL);

                if (rc != 0) {
                        cFYI(1, ("Create symlink ok, getinodeinfo fail rc = %d",
                              rc));
                } else {
                        if (pTcon->nocase)
                                direntry->d_op = &cifs_ci_dentry_ops;
                        else
                                direntry->d_op = &cifs_dentry_ops;
                        d_instantiate(direntry, newinode);
                }
        }

        kfree(full_path);
        FreeXid(xid);
        return rc;
}

void cifs_put_link(struct dentry *direntry, struct nameidata *nd, void *cookie)
{
        char *p = nd_get_link(nd);
        if (!IS_ERR(p))
                kfree(p);
}