Allow setting per-file compression via CIFS protocol

An earlier patch allowed setting the per-file compression flag

"chattr +c filename"

on an smb2 or smb3 mount, and also allowed lsattr to return
whether a file on a cifs, or smb2/smb3 mount was compressed.

This patch extends the ability to set the per-file
compression flag to the cifs protocol, which uses a somewhat
different IOCTL mechanism than SMB2, although the payload
(the flags stored in the compression_state) are the same.

Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <smfrench@gmail.com>
diff --git a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h
index b5ec2a2..aa33976 100644
--- a/fs/cifs/cifsproto.h
+++ b/fs/cifs/cifsproto.h
@@ -360,6 +360,8 @@
 extern int CIFSSMBQuerySymLink(const unsigned int xid, struct cifs_tcon *tcon,
 			       __u16 fid, char **symlinkinfo,
 			       const struct nls_table *nls_codepage);
+extern int CIFSSMB_set_compression(const unsigned int xid,
+				   struct cifs_tcon *tcon, __u16 fid);
 extern int CIFSSMBOpen(const unsigned int xid, struct cifs_tcon *tcon,
 			const char *fileName, const int disposition,
 			const int access_flags, const int omode,