cifs: Fix FALLOC_FL_ZERO_RANGE by setting i_size if EOF moved

Fix the cifs filesystem implementations of FALLOC_FL_ZERO_RANGE, in
smb3_zero_range(), to set i_size after extending the file on the server.

Fixes: 72c419d9b073 ("cifs: fix smb3_zero_range so it can expand the file-size when required")
Cc: [e-mail]
Signed-off-by: David Howells <[e-mail]>
Acked-by: Paulo Alcantara <[e-mail]>
cc: Shyam Prasad N <[e-mail]>
cc: Rohith Surabattula <[e-mail]>
cc: Jeff Layton <[e-mail]>
cc: [e-mail]
cc: [e-mail]
Signed-off-by: Steve French <[e-mail]>

fs/smb/client/smb2ops.c

···
 	struct inode *inode = file_inode(file);
 	struct cifsInodeInfo *cifsi = CIFS_I(inode);
 	struct cifsFileInfo *cfile = file->private_data;
+	unsigned long long new_size;
 	long rc;
 	unsigned int xid;
 	__le64 eof;
···
 	/*
 	 * do we also need to change the size of the file?
 	 */
-	if (keep_size == false && i_size_read(inode) < offset + len) {
-		eof = cpu_to_le64(offset + len);
+	new_size = offset + len;
+	if (keep_size == false && (unsigned long long)i_size_read(inode) < new_size) {
+		eof = cpu_to_le64(new_size);
 		rc = SMB2_set_eof(xid, tcon, cfile->fid.persistent_fid,
 				  cfile->fid.volatile_fid, cfile->pid, &eof);
+		if (rc >= 0) {
+			truncate_setsize(inode, new_size);
+			fscache_resize_cookie(cifs_inode_cookie(inode), new_size);
+		}
 	}
 
  zero_range_exit: