/*
 *   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"

void
smb2_set_oplock_level(struct cifsInodeInfo *cinode, __u32 oplock)
{
        oplock &= 0xFF;
        if (oplock == SMB2_OPLOCK_LEVEL_NOCHANGE)
                return;
        if (oplock == SMB2_OPLOCK_LEVEL_EXCLUSIVE) {
                cinode->clientCanCacheAll = true;
                cinode->clientCanCacheRead = true;
                cFYI(1, "Exclusive Oplock granted on inode %p",
                     &cinode->vfs_inode);
        } else if (oplock == SMB2_OPLOCK_LEVEL_II) {
                cinode->clientCanCacheAll = false;
                cinode->clientCanCacheRead = true;
                cFYI(1, "Level II Oplock granted on inode %p",
                    &cinode->vfs_inode);
        } else {
                cinode->clientCanCacheAll = false;
                cinode->clientCanCacheRead = false;
        }
}

int
smb2_open_file(const unsigned int xid, struct cifs_tcon *tcon, const char *path,
               int disposition, int desired_access, int create_options,
               struct cifs_fid *fid, __u32 *oplock, FILE_ALL_INFO *buf,
               struct cifs_sb_info *cifs_sb)
{
        int rc;
        __le16 *smb2_path;
        struct smb2_file_all_info *smb2_data = NULL;
        __u8 smb2_oplock[17];

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

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

        desired_access |= FILE_READ_ATTRIBUTES;
        *smb2_oplock = SMB2_OPLOCK_LEVEL_EXCLUSIVE;

        if (tcon->ses->server->capabilities & SMB2_GLOBAL_CAP_LEASING)
                memcpy(smb2_oplock + 1, fid->lease_key, SMB2_LEASE_KEY_SIZE);

        rc = SMB2_open(xid, tcon, smb2_path, &fid->persistent_fid,
                       &fid->volatile_fid, desired_access, disposition,
                       0, 0, smb2_oplock, smb2_data);
        if (rc)
                goto out;

        if (buf) {
                /* open response does not have IndexNumber field - get it */
                rc = SMB2_get_srv_num(xid, 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(cfile->dentry->d_inode);
        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 for zero before using.
         */
        max_buf = tcon->ses->server->maxBuf;
        if (!max_buf)
                return -EINVAL;

        max_num = max_buf / sizeof(struct smb2_lock_element);
        buf = kzalloc(max_num * sizeof(struct smb2_lock_element), GFP_KERNEL);
        if (!buf)
                return -ENOMEM;

        cur = buf;

        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)
                        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(cfile->dentry->d_inode);
        struct cifs_fid_locks *fdlocks;

        xid = get_xid();
        /* we are going to update can_cache_brlcks here - need a write access */
        down_write(&cinode->lock_sem);
        if (!cinode->can_cache_brlcks) {
                up_write(&cinode->lock_sem);
                free_xid(xid);
                return rc;
        }

        /*
         * 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) {
                up_write(&cinode->lock_sem);
                free_xid(xid);
                return -EINVAL;
        }

        max_num = max_buf / sizeof(struct smb2_lock_element);
        buf = kzalloc(max_num * sizeof(struct smb2_lock_element), GFP_KERNEL);
        if (!buf) {
                up_write(&cinode->lock_sem);
                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;
        }

        cinode->can_cache_brlcks = false;
        kfree(buf);

        up_write(&cinode->lock_sem);
        free_xid(xid);
        return rc;
}