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OvmfPkg/VirtioFsDxe: add a shared wrapper for FUSE_READ / FUSE_READDIRPLUS

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Add the VirtioFsFuseReadFileOrDir() function, for sending the FUSE_READ or
FUSE_READDIRPLUS command to the Virtio Filesystem device.

Parsing the structured FUSE_READDIRPLUS output is complex, and cannot be
integrated into the wrapper function. Given that fact, FUSE_READ and
FUSE_READDIRPLUS turn out to need identical low-level handling, except for
the opcode. Hence the shared wrapper function.

(It's prudent to verify whether the FUSE server supports FUSE_READDIRPLUS,
so update the session init code accordingly.)

This is the first FUSE request wrapper function that deals with a variable
size tail buffer.

Cc: Ard Biesheuvel <ard.biesheuvel@arm.com>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Philippe Mathieu-Daudé <philmd@redhat.com>
Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=3097
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Message-Id: <20201216211125.19496-33-lersek@redhat.com>
Acked-by: Ard Biesheuvel <ard.biesheuvel@arm.com>
This commit is contained in:
Laszlo Ersek
2020-12-16 22:11:09 +01:00
committed by mergify[bot]
parent c4edb49b4f
commit d98d7e3005
5 changed files with 276 additions and 4 deletions
Download Patch File Download Diff File Expand all files Collapse all files

10
OvmfPkg/VirtioFsDxe/FuseInit.c
View File

@@ -26,7 +26,8 @@
@retval EFI_SUCCESS The FUSE session has been started.
@retval EFI_UNSUPPORTED FUSE interface version negotiation failed.
@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
@@ -97,7 +98,7 @@ VirtioFsFuseInitSession (
InitReq.Major = VIRTIO_FS_FUSE_MAJOR;
InitReq.Minor = VIRTIO_FS_FUSE_MINOR;
InitReq.MaxReadahead = 0;
InitReq.Flags = 0;
InitReq.Flags = VIRTIO_FS_FUSE_INIT_REQ_F_DO_READDIRPLUS;
//
// Submit the request.
@@ -121,10 +122,11 @@ VirtioFsFuseInitSession (
}
//
// Check FUSE interface version compatibility.
// Check FUSE interface version / feature compatibility.
//
if (InitResp.Major < InitReq.Major ||
(InitResp.Major == InitReq.Major && InitResp.Minor < InitReq.Minor)) {
(InitResp.Major == InitReq.Major && InitResp.Minor < InitReq.Minor) ||
(InitResp.Flags & VIRTIO_FS_FUSE_INIT_REQ_F_DO_READDIRPLUS) == 0) {
return EFI_UNSUPPORTED;
}