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.