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Commit 76dcc26f authored by Jeff Layton's avatar Jeff Layton Committed by Steve French
Browse files

cifs: mangle existing header for SMB_COM_NT_CANCEL 



The NT_CANCEL command looks just like the original command, except for a
few small differences. The send_nt_cancel function however currently takes
a tcon, which we don't have in SendReceive and SendReceive2.

Instead of "respinning" the entire header for an NT_CANCEL, just mangle
the existing header by replacing just the fields we need. This means we
don't need a tcon and allows us to call it from other places.

Reviewed-by: default avatarPavel Shilovsky <piastryyy@gmail.com>
Reviewed-by: default avatarSuresh Jayaraman <sjayaraman@suse.de>
Signed-off-by: default avatarJeff Layton <jlayton@redhat.com>
Signed-off-by: default avatarSteve French <sfrench@us.ibm.com>
parent 7749981e

fs/cifs/transport.c

+38 −25
Original line number Diff line number Diff line
@@ -464,6 +464,43 @@ sync_mid_result(struct mid_q_entry *mid, struct TCP_Server_Info *server) 
	return rc;

}



/*

 * 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, struct smb_hdr *in_buf,

		struct mid_q_entry *mid)

{

	int rc = 0;



	/* -4 for RFC1001 length and +2 for BCC field */

	in_buf->smb_buf_length = sizeof(struct smb_hdr) - 4  + 2;

	in_buf->Command = SMB_COM_NT_CANCEL;

	in_buf->WordCount = 0;

	BCC_LE(in_buf) = 0;



	mutex_lock(&server->srv_mutex);

	rc = cifs_sign_smb(in_buf, server, &mid->sequence_number);

	if (rc) {

		mutex_unlock(&server->srv_mutex);

		return rc;

	}

	rc = smb_send(server, in_buf, in_buf->smb_buf_length);

	mutex_unlock(&server->srv_mutex);



	cFYI(1, "issued NT_CANCEL for mid %u, rc = %d",

		in_buf->Mid, rc);



	return rc;

}



int

SendReceive2(const unsigned int xid, struct cifsSesInfo *ses,

	     struct kvec *iov, int n_vec, int *pRespBufType /* ret */,
@@ -753,29 +790,6 @@ SendReceive(const unsigned int xid, struct cifsSesInfo *ses, 
	return rc;

}



/* Send an NT_CANCEL SMB to cause the POSIX blocking lock to return. */



static int

send_nt_cancel(struct cifsTconInfo *tcon, struct smb_hdr *in_buf,

		struct mid_q_entry *midQ)

{

	int rc = 0;

	struct cifsSesInfo *ses = tcon->ses;

	__u16 mid = in_buf->Mid;



	header_assemble(in_buf, SMB_COM_NT_CANCEL, tcon, 0);

	in_buf->Mid = mid;

	mutex_lock(&ses->server->srv_mutex);

	rc = cifs_sign_smb(in_buf, ses->server, &midQ->sequence_number);

	if (rc) {

		mutex_unlock(&ses->server->srv_mutex);

		return rc;

	}

	rc = smb_send(ses->server, in_buf, in_buf->smb_buf_length);

	mutex_unlock(&ses->server->srv_mutex);

	return rc;

}



/* We send a LOCKINGX_CANCEL_LOCK to cause the Windows

   blocking lock to return. */
@@ -890,8 +904,7 @@ SendReceiveBlockingLock(const unsigned int xid, struct cifsTconInfo *tcon, 
		if (in_buf->Command == SMB_COM_TRANSACTION2) {

			/* POSIX lock. We send a NT_CANCEL SMB to cause the

			   blocking lock to return. */



			rc = send_nt_cancel(tcon, in_buf, midQ);

			rc = send_nt_cancel(ses->server, in_buf, midQ);

			if (rc) {

				delete_mid(midQ);

				return rc;