smb2file.c

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/*
 *   fs/cifs/smb2file.c
 *
 *   Copyright (C) International Business Machines  Corp., 2002, 2011
 *   Author(s): Steve French ([email protected]),
 *              Pavel Shilovsky (([email protected]) 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;
}