smb: client: insert compression check/call on write requests

On smb2_async_writev(), set CIFS_COMPRESS_REQ on request flags if
should_compress() returns true.

On smb_send_rqst() check the flags, and compress and send the request to
the server.

(*) If the compression fails with -EMSGSIZE (i.e. compressed size is >=
uncompressed size), the original uncompressed request is sent instead.

Signed-off-by: Enzo Matsumiya <ematsumiya@suse.de>
Signed-off-by: Steve French <stfrench@microsoft.com>

Author: ematsumiya

fs/smb/client/smb2pdu.c

@@ -42,6 +42,7 @@
 #include "dfs_cache.h"
 #endif
 #include "cached_dir.h"
+#include "compress.h"
 
 /*
  *  The following table defines the expected "StructureSize" of SMB2 requests
@@ -5020,6 +5021,10 @@ smb2_async_writev(struct cifs_io_subrequest *wdata)
 		flags |= CIFS_HAS_CREDITS;
 	}
 
+	/* XXX: compression + encryption is unsupported for now */
+	if (((flags & CIFS_TRANSFORM_REQ) != CIFS_TRANSFORM_REQ) && should_compress(tcon, &rqst))
+		flags |= CIFS_COMPRESS_REQ;
+
 	rc = cifs_call_async(server, &rqst, NULL, smb2_writev_callback, NULL,
 			     wdata, flags, &wdata->credits);
 	/* Can't touch wdata if rc == 0 */

fs/smb/client/transport.c

@@ -28,6 +28,7 @@
 #include "cifs_debug.h"
 #include "smb2proto.h"
 #include "smbdirect.h"
+#include "compress.h"
 
 /* Max number of iovectors we can use off the stack when sending requests. */
 #define CIFS_MAX_IOV_SIZE 8
@@ -432,6 +433,9 @@ smb_send_rqst(struct TCP_Server_Info *server, int num_rqst,
 	struct kvec *iov;
 	int rc;
 
+	if (flags & CIFS_COMPRESS_REQ)
+		return smb_compress(server, &rqst[0], __smb_send_rqst);
+
 	if (!(flags & CIFS_TRANSFORM_REQ))
 		return __smb_send_rqst(server, num_rqst, rqst);