/*
 *   fs/cifs/smb2file.c
 *
 *   Copyright (C) International Business Machines  Corp., 2002, 2011
 *   Author(s): Steve French (sfrench@us.ibm.com),
 *              Pavel Shilovsky ((pshilovsky@samba.org) 2012
 *
 *   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/slab.h>
#include <linux/pagemap.h>
#include <asm/div64.h>
#include "cifsfs.h"
#include "cifspdu.h"
#include "cifsglob.h"
#include "cifsproto.h"
#include "cifs_debug.h"
#include "cifs_fs_sb.h"
#include "cifs_unicode.h"
#include "fscache.h"
#include "smb2proto.h"

int
smb2_open_file(const unsigned int xid, struct cifs_open_parms *oparms,
               __u32 *oplock, FILE_ALL_INFO *buf)
{
        int rc;
        __le16 *smb2_path;
        struct smb2_file_all_info *smb2_data = NULL;
        __u8 smb2_oplock;
        struct cifs_fid *fid = oparms->fid;
        struct network_resiliency_req nr_ioctl_req;

        smb2_path = cifs_convert_path_to_utf16(oparms->path, oparms->cifs_sb);
        if (smb2_path == NULL) {
                rc = -ENOMEM;
                goto out;
        }

        smb2_data = kzalloc(sizeof(struct smb2_file_all_info) + PATH_MAX * 2,
                            GFP_KERNEL);
        if (smb2_data == NULL) {
                rc = -ENOMEM;
                goto out;
        }

        oparms->desired_access |= FILE_READ_ATTRIBUTES;
        smb2_oplock = SMB2_OPLOCK_LEVEL_BATCH;

        rc = SMB2_open(xid, oparms, smb2_path, &smb2_oplock, smb2_data, NULL,
                       NULL, NULL);
        if (rc)
                goto out;


        if (oparms->tcon->use_resilient) {
                /* default timeout is 0, servers pick default (120 seconds) */
                nr_ioctl_req.Timeout =
                        cpu_to_le32(oparms->tcon->handle_timeout);
                nr_ioctl_req.Reserved = 0;
                rc = SMB2_ioctl(xid, oparms->tcon, fid->persistent_fid,
                        fid->volatile_fid, FSCTL_LMR_REQUEST_RESILIENCY,
                        true /* is_fsctl */,
                        (char *)&nr_ioctl_req, sizeof(nr_ioctl_req),
                        CIFSMaxBufSize, NULL, NULL /* no return info */);
                if (rc == -EOPNOTSUPP) {
                        cifs_dbg(VFS,
                             "resiliency not supported by server, disabling\n");
                        oparms->tcon->use_resilient = false;
                } else if (rc)
                        cifs_dbg(FYI, "error %d setting resiliency\n", rc);

                rc = 0;
        }

        if (buf) {
                /* if open response does not have IndexNumber field - get it */
                if (smb2_data->IndexNumber == 0) {
                        rc = SMB2_get_srv_num(xid, oparms->tcon,
                                      fid->persistent_fid,
                                      fid->volatile_fid,
                                      &smb2_data->IndexNumber);
                        if (rc) {
                                /*
                                 * let get_inode_info disable server inode
                                 * numbers
                                 */
                                smb2_data->IndexNumber = 0;
                                rc = 0;
                        }
                }
                move_smb2_info_to_cifs(buf, smb2_data);
        }

        *oplock = smb2_oplock;
out:
        kfree(smb2_data);
        kfree(smb2_path);
        return rc;
}

int
smb2_unlock_range(struct cifsFileInfo *cfile, struct file_lock *flock,
                  const unsigned int xid)
{
        int rc = 0, stored_rc;
        unsigned int max_num, num = 0, max_buf;
        struct smb2_lock_element *buf, *cur;
        struct cifs_tcon *tcon = tlink_tcon(cfile->tlink);
        struct cifsInodeInfo *cinode = CIFS_I(d_inode(cfile->dentry));
        struct cifsLockInfo *li, *tmp;
        __u64 length = 1 + flock->fl_end - flock->fl_start;
        struct list_head tmp_llist;

        INIT_LIST_HEAD(&tmp_llist);

        /*
         * Accessing maxBuf is racy with cifs_reconnect - need to store value
         * and check it before using.
         */
        max_buf = tcon->ses->server->maxBuf;
        if (max_buf < sizeof(struct smb2_lock_element))
                return -EINVAL;

        BUILD_BUG_ON(sizeof(struct smb2_lock_element) > PAGE_SIZE);
        max_buf = min_t(unsigned int, max_buf, PAGE_SIZE);
        max_num = max_buf / sizeof(struct smb2_lock_element);
        buf = kcalloc(max_num, sizeof(struct smb2_lock_element), GFP_KERNEL);
        if (!buf)
                return -ENOMEM;

        cur = buf;

        cifs_down_write(&cinode->lock_sem);
        list_for_each_entry_safe(li, tmp, &cfile->llist->locks, llist) {
                if (flock->fl_start > li->offset ||
                    (flock->fl_start + length) <
                    (li->offset + li->length))
                        continue;
                if (current->tgid != li->pid)
                        /*
                         * flock and OFD lock are associated with an open
                         * file description, not the process.
                         */
                        if (!(flock->fl_flags & (FL_FLOCK | FL_OFDLCK)))
                                continue;
                if (cinode->can_cache_brlcks) {
                        /*
                         * We can cache brlock requests - simply remove a lock
                         * from the file's list.
                         */
                        list_del(&li->llist);
                        cifs_del_lock_waiters(li);
                        kfree(li);
                        continue;
                }
                cur->Length = cpu_to_le64(li->length);
                cur->Offset = cpu_to_le64(li->offset);
                cur->Flags = cpu_to_le32(SMB2_LOCKFLAG_UNLOCK);
                /*
                 * We need to save a lock here to let us add it again to the
                 * file's list if the unlock range request fails on the server.
                 */
                list_move(&li->llist, &tmp_llist);
                if (++num == max_num) {
                        stored_rc = smb2_lockv(xid, tcon,
                                               cfile->fid.persistent_fid,
                                               cfile->fid.volatile_fid,
                                               current->tgid, num, buf);
                        if (stored_rc) {
                                /*
                                 * We failed on the unlock range request - add
                                 * all locks from the tmp list to the head of
                                 * the file's list.
                                 */
                                cifs_move_llist(&tmp_llist,
                                                &cfile->llist->locks);
                                rc = stored_rc;
                        } else
                                /*
                                 * The unlock range request succeed - free the
                                 * tmp list.
                                 */
                                cifs_free_llist(&tmp_llist);
                        cur = buf;
                        num = 0;
                } else
                        cur++;
        }
        if (num) {
                stored_rc = smb2_lockv(xid, tcon, cfile->fid.persistent_fid,
                                       cfile->fid.volatile_fid, current->tgid,
                                       num, buf);
                if (stored_rc) {
                        cifs_move_llist(&tmp_llist, &cfile->llist->locks);
                        rc = stored_rc;
                } else
                        cifs_free_llist(&tmp_llist);
        }
        up_write(&cinode->lock_sem);

        kfree(buf);
        return rc;
}

static int
smb2_push_mand_fdlocks(struct cifs_fid_locks *fdlocks, const unsigned int xid,
                       struct smb2_lock_element *buf, unsigned int max_num)
{
        int rc = 0, stored_rc;
        struct cifsFileInfo *cfile = fdlocks->cfile;
        struct cifsLockInfo *li;
        unsigned int num = 0;
        struct smb2_lock_element *cur = buf;
        struct cifs_tcon *tcon = tlink_tcon(cfile->tlink);

        list_for_each_entry(li, &fdlocks->locks, llist) {
                cur->Length = cpu_to_le64(li->length);
                cur->Offset = cpu_to_le64(li->offset);
                cur->Flags = cpu_to_le32(li->type |
                                                SMB2_LOCKFLAG_FAIL_IMMEDIATELY);
                if (++num == max_num) {
                        stored_rc = smb2_lockv(xid, tcon,
                                               cfile->fid.persistent_fid,
                                               cfile->fid.volatile_fid,
                                               current->tgid, num, buf);
                        if (stored_rc)
                                rc = stored_rc;
                        cur = buf;
                        num = 0;
                } else
                        cur++;
        }
        if (num) {
                stored_rc = smb2_lockv(xid, tcon,
                                       cfile->fid.persistent_fid,
                                       cfile->fid.volatile_fid,
                                       current->tgid, num, buf);
                if (stored_rc)
                        rc = stored_rc;
        }

        return rc;
}

int
smb2_push_mandatory_locks(struct cifsFileInfo *cfile)
{
        int rc = 0, stored_rc;
        unsigned int xid;
        unsigned int max_num, max_buf;
        struct smb2_lock_element *buf;
        struct cifsInodeInfo *cinode = CIFS_I(d_inode(cfile->dentry));
        struct cifs_fid_locks *fdlocks;

        xid = get_xid();

        /*
         * Accessing maxBuf is racy with cifs_reconnect - need to store value
         * and check it for zero before using.
         */
        max_buf = tlink_tcon(cfile->tlink)->ses->server->maxBuf;
        if (max_buf < sizeof(struct smb2_lock_element)) {
                free_xid(xid);
                return -EINVAL;
        }

        BUILD_BUG_ON(sizeof(struct smb2_lock_element) > PAGE_SIZE);
        max_buf = min_t(unsigned int, max_buf, PAGE_SIZE);
        max_num = max_buf / sizeof(struct smb2_lock_element);
        buf = kcalloc(max_num, sizeof(struct smb2_lock_element), GFP_KERNEL);
        if (!buf) {
                free_xid(xid);
                return -ENOMEM;
        }

        list_for_each_entry(fdlocks, &cinode->llist, llist) {
                stored_rc = smb2_push_mand_fdlocks(fdlocks, xid, buf, max_num);
                if (stored_rc)
                        rc = stored_rc;
        }

        kfree(buf);
        free_xid(xid);
        return rc;
}