path: root/fs/cifs/smb1ops.c

/*
 *  SMB1 (CIFS) version specific operations
 *
 *  Copyright (c) 2012, Jeff Layton <jlayton@redhat.com>
 *
 *  This library is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License v2 as published
 *  by the Free Software Foundation.
 *
 *  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/pagemap.h>
#include <linux/vfs.h>
#include "cifsglob.h"
#include "cifsproto.h"
#include "cifs_debug.h"
#include "cifspdu.h"

/*
 * An NT cancel request header looks just like the original request except:
 *
 * The Command is SMB_COM_NT_CANCEL
 * The WordCount is zeroed out
 * The ByteCount is zeroed out
 *
 * This function mangles an existing request buffer into a
 * SMB_COM_NT_CANCEL request and then sends it.
 */
static int
send_nt_cancel(struct TCP_Server_Info *server, void *buf,
	       struct mid_q_entry *mid)
{
	int rc = 0;
	struct smb_hdr *in_buf = (struct smb_hdr *)buf;

	/* -4 for RFC1001 length and +2 for BCC field */
	in_buf->smb_buf_length = cpu_to_be32(sizeof(struct smb_hdr) - 4  + 2);
	in_buf->Command = SMB_COM_NT_CANCEL;
	in_buf->WordCount = 0;
	put_bcc(0, in_buf);

	mutex_lock(&server->srv_mutex);
	rc = cifs_sign_smb(in_buf, server, &mid->sequence_number);
	if (rc) {
		mutex_unlock(&server->srv_mutex);
		return rc;
	}

	/*
	 * The response to this call was already factored into the sequence
	 * number when the call went out, so we must adjust it back downward
	 * after signing here.
	 */
	--server->sequence_number;
	rc = smb_send(server, in_buf, be32_to_cpu(in_buf->smb_buf_length));
	if (rc < 0)
		server->sequence_number--;

	mutex_unlock(&server->srv_mutex);

	cifs_dbg(FYI, "issued NT_CANCEL for mid %u, rc = %d\n",
		 get_mid(in_buf), rc);

	return rc;
}

static bool
cifs_compare_fids(struct cifsFileInfo *ob1, struct cifsFileInfo *ob2)
{
	return ob1->fid.netfid == ob2->fid.netfid;
}

static unsigned int
cifs_read_data_offset(char *buf)
{
	READ_RSP *rsp = (READ_RSP *)buf;
	return le16_to_cpu(rsp->DataOffset);
}

static unsigned int
cifs_read_data_length(char *buf)
{
	READ_RSP *rsp = (READ_RSP *)buf;
	return (le16_to_cpu(rsp->DataLengthHigh) << 16) +
	       le16_to_cpu(rsp->DataLength);
}

static struct mid_q_entry *
cifs_find_mid(struct TCP_Server_Info *server, char *buffer)
{
	struct smb_hdr *buf = (struct smb_hdr *)buffer;
	struct mid_q_entry *mid;

	spin_lock(&GlobalMid_Lock);
	list_for_each_entry(mid, &server->pending_mid_q, qhead) {
		if (compare_mid(mid->mid, buf) &&
		    mid->mid_state == MID_REQUEST_SUBMITTED &&
		    le16_to_cpu(mid->command) == buf->Command) {
			spin_unlock(&GlobalMid_Lock);
			return mid;
		}
	}
	spin_unlock(&GlobalMid_Lock);
	return NULL;
}

static void
cifs_add_credits(struct TCP_Server_Info *server, const unsigned int add,
		 const int optype)
{
	spin_lock(&server->req_lock);
	server->credits += add;
	server->in_flight--;
	spin_unlock(&server->req_lock);
	wake_up(&server->request_q);
}

static void
cifs_set_credits(struct TCP_Server_Info *server, const int val)
{
	spin_lock(&server->req_lock);
	server->credits = val;
	server->oplocks = val > 1 ? enable_oplocks : false;
	spin_unlock(&server->req_lock);
}

static