Steve I use _IOWR() for this IOCTL since we both write the buffer from userspace to kernel when we invoke the query and then write the buffer back to userspace when the query has finished. Additionally, for query-quota, we pass data buffers both from client to server and also from server back to client as part of the processing. Based on this kernel comment that defined the _IO macros I think _IOWR is the right one to use. /* * Used to create numbers. * * NOTE: _IOW means userland is writing and kernel is reading. _IOR * means userland is reading and kernel is writing. */ ----- Original Message ----- From: "Ronnie Sahlberg" <lsahlber@xxxxxxxxxx> To: "linux-cifs" <linux-cifs@xxxxxxxxxxxxxxx> Cc: "Steve French" <smfrench@xxxxxxxxx> Sent: Wednesday, 3 October, 2018 10:42:01 AM Subject: [PATCH 0/2] cifs: Add IOCTL passthrough for QUERY-INFO Steve, All Please find two patches. The first patch is for the kernel and adds an IOCTL to allow passthrough to the SMB server for QUERY-INFO commands. The Second is a patch to cifs-utils that adds a new command smbinfo that can be used to display the securityDescriptor of a file or to show the Quotas for a volume. The second is just a start and it would be nice to extend this to query all types of information that can be retreived by Query-Info
