> -----Original Message-----
> From: Li Tian <[email protected]>
> Sent: Sunday, April 5, 2026 6:54 PM
> To: [email protected]
> Cc: Li Tian <[email protected]>; KY Srinivasan <[email protected]>; Haiyang
> Zhang <[email protected]>; Wei Liu <[email protected]>; Dexuan Cui
> <[email protected]>; Long Li <[email protected]>; James E.J. Bottomley
> <[email protected]>; Martin K. Petersen
> <[email protected]>; [email protected]; linux-
> [email protected]
> Subject: [EXTERNAL] [PATCH] scsi: storvsc: Handle PERSISTENT_RESERVE_IN
> truncation for Hyper-V vFC
>
> The storvsc driver has become stricter in handling SRB status codes returned
> by
> the Hyper-V host. When using Virtual Fibre Channel (vFC) passthrough, the host
> may return SRB_STATUS_DATA_OVERRUN for PERSISTENT_RESERVE_IN
> commands if the allocation length in the CDB does not match the host's
> expected
> response size.
>
> Currently, this status is treated as a fatal error, propagating
> Host_status=0x07 [DID_ERROR] to the SCSI mid-layer. This causes userspace
> storage utilities (such as sg_persist) to fail with transport errors, even
> when the
> host has actually returned the requested reservation data in the buffer.
>
> Refactor the existing command-specific workarounds into a new helper function,
> storvsc_host_mishandles_cmd(), and add PERSISTENT_RESERVE_IN to the list of
> commands where SRB status errors should be suppressed for vFC devices. This
> ensures that the SCSI mid-layer processes the returned data buffer instead of
> terminating the command.
>
> Signed-off-by: Li Tian <[email protected]>
Reviewed-by: Long Li <[email protected]>
> ---
> drivers/scsi/storvsc_drv.c | 32 +++++++++++++++++++++-----------
> 1 file changed, 21 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/scsi/storvsc_drv.c b/drivers/scsi/storvsc_drv.c index
> ae1abab97835..6977ca8a0658 100644
> --- a/drivers/scsi/storvsc_drv.c
> +++ b/drivers/scsi/storvsc_drv.c
> @@ -1131,6 +1131,26 @@ static void storvsc_command_completion(struct
> storvsc_cmd_request *cmd_request,
> kfree(payload);
> }
>
> +/*
> + * The current SCSI handling on the host side does not correctly handle:
> + * INQUIRY with page code 0x80, MODE_SENSE / MODE_SENSE_10 with
> cmd[2]
> +== 0x1c,
> + * and (for FC) MAINTENANCE_IN / PERSISTENT_RESERVE_IN passthrough.
> + */
> +static bool storvsc_host_mishandles_cmd(u8 opcode, struct hv_device
> +*device) {
> + switch (opcode) {
> + case INQUIRY:
> + case MODE_SENSE:
> + case MODE_SENSE_10:
> + return true;
> + case MAINTENANCE_IN:
> + case PERSISTENT_RESERVE_IN:
> + return hv_dev_is_fc(device);
> + default:
> + return false;
> + }
> +}
> +
> static void storvsc_on_io_completion(struct storvsc_device *stor_device,
> struct vstor_packet *vstor_packet,
> struct storvsc_cmd_request *request) @@ -
> 1141,22 +1161,12 @@ static void storvsc_on_io_completion(struct
> storvsc_device *stor_device,
> stor_pkt = &request->vstor_packet;
>
> /*
> - * The current SCSI handling on the host side does
> - * not correctly handle:
> - * INQUIRY command with page code parameter set to 0x80
> - * MODE_SENSE and MODE_SENSE_10 command with cmd[2] == 0x1c
> - * MAINTENANCE_IN is not supported by HyperV FC passthrough
> - *
> * Setup srb and scsi status so this won't be fatal.
> * We do this so we can distinguish truly fatal failues
> * (srb status == 0x4) and off-line the device in that case.
> */
>
> - if ((stor_pkt->vm_srb.cdb[0] == INQUIRY) ||
> - (stor_pkt->vm_srb.cdb[0] == MODE_SENSE) ||
> - (stor_pkt->vm_srb.cdb[0] == MODE_SENSE_10) ||
> - (stor_pkt->vm_srb.cdb[0] == MAINTENANCE_IN &&
> - hv_dev_is_fc(device))) {
> + if (storvsc_host_mishandles_cmd(stor_pkt->vm_srb.cdb[0], device)) {
> vstor_packet->vm_srb.scsi_status = 0;
> vstor_packet->vm_srb.srb_status = SRB_STATUS_SUCCESS;
> }
> --
> 2.53.0
