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/** @file
FUSE_INIT wrapper for the Virtio Filesystem device.
Copyright (C) 2020, Red Hat, Inc.
SPDX-License-Identifier: BSD-2-Clause-Patent
**/
#include "VirtioFsDxe.h"
/**
Send a FUSE_INIT request to the Virtio Filesystem device, for starting the
FUSE session.
From virtio-v1.1-cs01-87fa6b5d8155, 5.11.5 Device Initialization: "On
initialization the driver first discovers the device's virtqueues. The FUSE
session is started by sending a FUSE_INIT request as defined by the FUSE
protocol on one request virtqueue."
The function may only be called after VirtioFsInit() returns successfully and
before VirtioFsUninit() is called.
@param[in,out] VirtioFs The Virtio Filesystem device to send the FUSE_INIT
request to. The FUSE request counter
"VirtioFs->RequestId" is set to 1 on output. The
maximum write buffer size exposed in the FUSE_INIT
response is saved in "VirtioFs->MaxWrite", on
output.
@retval EFI_SUCCESS The FUSE session has been started.
@retval EFI_UNSUPPORTED FUSE interface version or feature negotiation
failed.
@return The "errno" value mapped to an EFI_STATUS code, if
the Virtio Filesystem device explicitly reported an
error.
@return Error codes propagated from
VirtioFsSgListsValidate(), VirtioFsFuseNewRequest(),
VirtioFsSgListsSubmit(),
VirtioFsFuseCheckResponse().
**/
EFI_STATUS
VirtioFsFuseInitSession (
IN OUT VIRTIO_FS *VirtioFs
)
{
VIRTIO_FS_FUSE_REQUEST CommonReq;
VIRTIO_FS_FUSE_INIT_REQUEST InitReq;
VIRTIO_FS_IO_VECTOR ReqIoVec[2];
VIRTIO_FS_SCATTER_GATHER_LIST ReqSgList;
VIRTIO_FS_FUSE_RESPONSE CommonResp;
VIRTIO_FS_FUSE_INIT_RESPONSE InitResp;
VIRTIO_FS_IO_VECTOR RespIoVec[2];
VIRTIO_FS_SCATTER_GATHER_LIST RespSgList;
EFI_STATUS Status;
//
// Initialize the FUSE request counter.
//
VirtioFs->RequestId = 1;
//
// Set up the scatter-gather lists.
//
ReqIoVec[0].Buffer = &CommonReq;
ReqIoVec[0].Size = sizeof CommonReq;
ReqIoVec[1].Buffer = &InitReq;
ReqIoVec[1].Size = sizeof InitReq;
ReqSgList.IoVec = ReqIoVec;
ReqSgList.NumVec = ARRAY_SIZE (ReqIoVec);
RespIoVec[0].Buffer = &CommonResp;
RespIoVec[0].Size = sizeof CommonResp;
RespIoVec[1].Buffer = &InitResp;
RespIoVec[1].Size = sizeof InitResp;
RespSgList.IoVec = RespIoVec;
RespSgList.NumVec = ARRAY_SIZE (RespIoVec);
//
// Validate the scatter-gather lists; calculate the total transfer sizes.
//
Status = VirtioFsSgListsValidate (VirtioFs, &ReqSgList, &RespSgList);
if (EFI_ERROR (Status)) {
return Status;
}
//
// Populate the common request header.
//
Status = VirtioFsFuseNewRequest (
VirtioFs,
&CommonReq,
ReqSgList.TotalSize,
VirtioFsFuseOpInit,
0
);
if (EFI_ERROR (Status)) {
return Status;
}
//
// Populate the FUSE_INIT-specific fields.
//
InitReq.Major = VIRTIO_FS_FUSE_MAJOR;
InitReq.Minor = VIRTIO_FS_FUSE_MINOR;
InitReq.MaxReadahead = 0;
InitReq.Flags = VIRTIO_FS_FUSE_INIT_REQ_F_DO_READDIRPLUS;
//
// Submit the request.
//
Status = VirtioFsSgListsSubmit (VirtioFs, &ReqSgList, &RespSgList);
if (EFI_ERROR (Status)) {
return Status;
}
//
// Verify the response (all response buffers are fixed size).
//
Status = VirtioFsFuseCheckResponse (&RespSgList, CommonReq.Unique, NULL);
if (EFI_ERROR (Status)) {
if (Status == EFI_DEVICE_ERROR) {
DEBUG ((
DEBUG_ERROR,
"%a: Label=\"%s\" Errno=%d\n",
__func__,
VirtioFs->Label,
CommonResp.Error
));
Status = VirtioFsErrnoToEfiStatus (CommonResp.Error);
}
return Status;
}
//
// Check FUSE interface version / feature compatibility.
//
if ((InitResp.Major < InitReq.Major) ||
((InitResp.Major == InitReq.Major) && (InitResp.Minor < InitReq.Minor)) ||
((InitResp.Flags & VIRTIO_FS_FUSE_INIT_REQ_F_DO_READDIRPLUS) == 0) ||
(InitResp.MaxWrite < SIZE_4KB))
{
return EFI_UNSUPPORTED;
}
//
// Save the maximum write buffer size for FUSE_WRITE requests.
//
VirtioFs->MaxWrite = InitResp.MaxWrite;
return EFI_SUCCESS;
}
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