CIFS: Add readpage support for SMB2

Signed-off-by: Pavel Shilovsky <pshilovsky@samba.org>
Signed-off-by: Steve French <smfrench@gmail.com>

1 files changed, 51 insertions, 0 deletions

diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
index cb6acc7b1ca8..23c569386f32 100644
--- a/fs/cifs/smb2pdu.c
+++ b/fs/cifs/smb2pdu.c
@@ -1329,6 +1329,57 @@ smb2_async_readv(struct cifs_readdata *rdata)
 	return rc;
 }
 
+int
+SMB2_read(const unsigned int xid, struct cifs_io_parms *io_parms,
+	  unsigned int *nbytes, char **buf, int *buf_type)
+{
+	int resp_buftype, rc = -EACCES;
+	struct smb2_read_rsp *rsp = NULL;
+	struct kvec iov[1];
+
+	*nbytes = 0;
+	rc = smb2_new_read_req(iov, io_parms, 0, 0);
+	if (rc)
+		return rc;
+
+	rc = SendReceive2(xid, io_parms->tcon->ses, iov, 1,
+			  &resp_buftype, CIFS_LOG_ERROR);
+
+	rsp = (struct smb2_read_rsp *)iov[0].iov_base;
+
+	if (rsp->hdr.Status == STATUS_END_OF_FILE) {
+		free_rsp_buf(resp_buftype, iov[0].iov_base);
+		return 0;
+	}
+
+	if (rc) {
+		cifs_stats_fail_inc(io_parms->tcon, SMB2_READ_HE);
+		cERROR(1, "Send error in read = %d", rc);
+	} else {
+		*nbytes = le32_to_cpu(rsp->DataLength);
+		if ((*nbytes > CIFS_MAX_MSGSIZE) ||
+		    (*nbytes > io_parms->length)) {
+			cFYI(1, "bad length %d for count %d", *nbytes,
+				io_parms->length);
+			rc = -EIO;
+			*nbytes = 0;
+		}
+	}
+
+	if (*buf) {
+		memcpy(*buf, (char *)rsp->hdr.ProtocolId + rsp->DataOffset,
+		       *nbytes);
+		free_rsp_buf(resp_buftype, iov[0].iov_base);
+	} else if (resp_buftype != CIFS_NO_BUFFER) {
+		*buf = iov[0].iov_base;
+		if (resp_buftype == CIFS_SMALL_BUFFER)
+			*buf_type = CIFS_SMALL_BUFFER;
+		else if (resp_buftype == CIFS_LARGE_BUFFER)
+			*buf_type = CIFS_LARGE_BUFFER;
+	}
+	return rc;
+}
+
 /*
  * Check the mid_state and signature on received buffer (if any), and queue the
  * workqueue completion task.