Commit 622695a4 authored by Ronnie Sahlberg's avatar Ronnie Sahlberg Committed by Paolo Bonzini
Browse files

ISCSI: force use of sg for SMC and SSC devices 



If the device we open is a SMC or SSC device, then force the use of sg. We
dont have any medium changer or tape emulation so only passthrough via
real sg or scsi-generic via iscsi would work anyway.

Forcing sg also makes qemu skip trying to read from the device to guess
the image format by reading from the device (find_image_format()).
SMC devices do not implement READ6/10/12/16 so it is not possible to
read from them (SSC have different CDBs).

With this patch I can successfully manage a SMC device wiht iscsi in
passthrough mode.

Signed-off-by: default avatarRonnie Sahlberg <ronniesahlberg@gmail.com>
[Added TYPE_TAPE handling - Paolo]
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 98392453

block/iscsi.c

+10 −0
Original line number Diff line number Diff line
@@ -1022,6 +1022,16 @@ static int iscsi_open(BlockDriverState *bs, const char *filename, int flags) 
    if (iscsi_url != NULL) {

        iscsi_destroy_url(iscsi_url);

    }



    /* Medium changer or tape. We dont have any emulation for this so this must

     * be sg ioctl compatible. We force it to be sg, otherwise qemu will try

     * to read from the device to guess the image format.

     */

    if (iscsilun->type == TYPE_MEDIUM_CHANGER ||

        iscsilun->type == TYPE_TAPE) {

        bs->sg = 1;

    }



    return 0;



failed: