Re: [edk2-devel] [PATCH 2/3] MdeModulePkg/PartitionDxe: Remove the check for special MBR

["Gao, Zhichao" <zhichao.gao@intel.com>]

I also add some variables to calculate StartingLBA and SizeInLBA instead of calculate them when they are needed.
I am fine to revert the whole changes. Just make you aware of this.

Thanks,
Zhichao

> -----Original Message-----
> From: devel@edk2.groups.io <devel@edk2.groups.io> On Behalf Of Ni, Ray
> Sent: Tuesday, August 11, 2020 4:06 PM
> To: Gao, Zhichao <zhichao.gao@intel.com>; devel@edk2.groups.io
> Cc: Wang, Jian J <jian.j.wang@intel.com>; Wu, Hao A <hao.a.wu@intel.com>;
> Gary Lin <glin@suse.com>; Andrew Fish <afish@apple.com>
> Subject: Re: [edk2-devel] [PATCH 2/3] MdeModulePkg/PartitionDxe: Remove
> the check for special MBR
> 
> Zhichao,
> Can you please just revert the fix you recently added?
> 
> > -----Original Message-----
> > From: Gao, Zhichao <zhichao.gao@intel.com>
> > Sent: Tuesday, August 11, 2020 2:43 PM
> > To: devel@edk2.groups.io
> > Cc: Wang, Jian J <jian.j.wang@intel.com>; Wu, Hao A
> > <hao.a.wu@intel.com>; Ni, Ray <ray.ni@intel.com>; Gary Lin
> > <glin@suse.com>; Andrew Fish <afish@apple.com>
> > Subject: [PATCH 2/3] MdeModulePkg/PartitionDxe: Remove the check for
> > special MBR
> >
> > REF: https://bugzilla.tianocore.org/show_bug.cgi?id=2823
> >
> > Follow the spec definition, the ISO 9660 (and UDF) would be checked
> > before the MBR. So it is not required to skip such MBR talbe that
> > contian the entire block device.
> >
> > Cc: Jian J Wang <jian.j.wang@intel.com>
> > Cc: Hao A Wu <hao.a.wu@intel.com>
> > Cc: Ray Ni <ray.ni@intel.com>
> > Cc: Gary Lin <glin@suse.com>
> > Cc: Andrew Fish <afish@apple.com>
> > Signed-off-by: Zhichao Gao <zhichao.gao@intel.com>
> > ---
> >  .../Universal/Disk/PartitionDxe/Mbr.c         | 19 -------------------
> >  1 file changed, 19 deletions(-)
> >
> > diff --git a/MdeModulePkg/Universal/Disk/PartitionDxe/Mbr.c
> > b/MdeModulePkg/Universal/Disk/PartitionDxe/Mbr.c
> > index 3830af1ea7..822bf03e92 100644
> > --- a/MdeModulePkg/Universal/Disk/PartitionDxe/Mbr.c
> > +++ b/MdeModulePkg/Universal/Disk/PartitionDxe/Mbr.c
> > @@ -55,25 +55,6 @@ PartitionValidMbr (
> >      StartingLBA = UNPACK_UINT32 (Mbr->Partition[Index1].StartingLBA);
> >      SizeInLBA   = UNPACK_UINT32 (Mbr->Partition[Index1].SizeInLBA);
> >
> > -    //
> > -    // If the MBR with partition entry covering the ENTIRE disk, i.e. start at
> LBA0
> > -    // with whole disk size, we treat it as an invalid MBR partition.
> > -    //
> > -    if ((StartingLBA == 0) &&
> > -        (SizeInLBA == (LastLba + 1))) {
> > -      //
> > -      // Refer to the
> http://manpages.ubuntu.com/manpages/bionic/man8/mkudffs.8.html
> > -      // "WHOLE DISK VS PARTITION"
> > -      // Some linux ISOs may put the MBR table in the first 512 bytes for
> compatibility reasons with Windows.
> > -      // Linux  kernel  ignores MBR table if contains partition which starts at
> sector 0.
> > -      // Skip it because we don't have the partition check for UDF(El Torito
> compatible).
> > -      // It would continue to do the whole disk check in the UDF routine.
> > -      //
> > -      DEBUG ((DEBUG_INFO, "PartitionValidMbr: MBR table has partition entry
> covering the ENTIRE disk. Don't treat it as a
> > valid MBR.\n"));
> > -
> > -      return FALSE;
> > -    }
> > -
> >      if (Mbr->Partition[Index1].OSIndicator == 0x00 || SizeInLBA == 0) {
> >        continue;
> >      }
> > --
> > 2.21.0.windows.1
> 
> 
>