[PATCH] disk: part_efi: update partition table entries after write

[PATCH] disk: part_efi: update partition table entries after write

[Gary Bisson]

Fixes fastboot issues when switching from mbr to gpt partition tables.

Signed-off-by: Gary Bisson <gary.bisson@boundarydevices.com>
---
Hi,

I hesitated calling this a RFC as I'm not sure everyone will like the
idea.

Basically the issue encountered was the following:
- Device with its storage flashed with a MBR partition table
- Run fastboot to flash a new OS (and new partition table)
- After flashing a GPT partition table, U-Boot couldn't find any of the
  partition names from the GPT
  -> reason is that the partition table entries aren't updated
  -> so U-Boot still believes it's a MBR table inside and so its parsing
  fails

This commit adds an update of the table entries inside the
write_mbr_and_gpt_partitions() function. At first I thought maybe this
should be added in fastboot file (fb_mmc.c) but couldn't think of a good
reason why this shouldn't happened in part_efi directly.

Let me know if you have any questions.

Regards,
Gary
---
 disk/part_efi.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/disk/part_efi.c b/disk/part_efi.c
index 2f922662e6e..7a24e33d189 100644
--- a/disk/part_efi.c
+++ b/disk/part_efi.c
@@ -867,6 +867,9 @@ int write_mbr_and_gpt_partitions(struct blk_desc *dev_desc, void *buf)
 		return 1;
 	}
 
+	/* Update the partition table entries*/
+	part_init(dev_desc);
+
 	return 0;
 }
 #endif
-- 
2.29.2

[PATCH] disk: part_efi: update partition table entries after write

[Heinrich Schuchardt]

On 26.01.21 14:56, Gary Bisson wrote:
> Fixes fastboot issues when switching from mbr to gpt partition tables.
>
> Signed-off-by: Gary Bisson <gary.bisson@boundarydevices.com>
> ---
> Hi,
>
> I hesitated calling this a RFC as I'm not sure everyone will like the
> idea.
>
> Basically the issue encountered was the following:
> - Device with its storage flashed with a MBR partition table
> - Run fastboot to flash a new OS (and new partition table)
> - After flashing a GPT partition table, U-Boot couldn't find any of the
>   partition names from the GPT
>   -> reason is that the partition table entries aren't updated
>   -> so U-Boot still believes it's a MBR table inside and so its parsing
>   fails
>
> This commit adds an update of the table entries inside the
> write_mbr_and_gpt_partitions() function. At first I thought maybe this
> should be added in fastboot file (fb_mmc.c) but couldn't think of a good
> reason why this shouldn't happened in part_efi directly.
>
> Let me know if you have any questions.
>
> Regards,
> Gary
> ---
>  disk/part_efi.c | 3 +++
>  1 file changed, 3 insertions(+)
>
> diff --git a/disk/part_efi.c b/disk/part_efi.c
> index 2f922662e6e..7a24e33d189 100644
> --- a/disk/part_efi.c
> +++ b/disk/part_efi.c
> @@ -867,6 +867,9 @@ int write_mbr_and_gpt_partitions(struct blk_desc *dev_desc, void *buf)
>  		return 1;
>  	}
>
> +	/* Update the partition table entries*/
> +	part_init(dev_desc);
> +
>  	return 0;
>  }
>  #endif
>

This change is for GPT only. Don't we need the same for MBR partition
tables (write_mbr_partitions())?

@Simon:

Essentially this reflashing is similar to changing media. What I am
missing in part_init() is setting a field with a counter to indicate the
media change. The EFI_BLOCK_IO_PROTOCOL has a u32 field media_id. Would
struct blk_desc be the right place to add such a field.

Best regards

Heinrich

[PATCH] disk: part_efi: update partition table entries after write

[Gary Bisson]

Hi Heinrich,

On Tue, Jan 26, 2021 at 04:08:13PM +0100, Heinrich Schuchardt wrote:
> On 26.01.21 14:56, Gary Bisson wrote:
> > Fixes fastboot issues when switching from mbr to gpt partition tables.
> >
> > Signed-off-by: Gary Bisson <gary.bisson@boundarydevices.com>
> > ---
> > Hi,
> >
> > I hesitated calling this a RFC as I'm not sure everyone will like the
> > idea.
> >
> > Basically the issue encountered was the following:
> > - Device with its storage flashed with a MBR partition table
> > - Run fastboot to flash a new OS (and new partition table)
> > - After flashing a GPT partition table, U-Boot couldn't find any of the
> >   partition names from the GPT
> >   -> reason is that the partition table entries aren't updated
> >   -> so U-Boot still believes it's a MBR table inside and so its parsing
> >   fails
> >
> > This commit adds an update of the table entries inside the
> > write_mbr_and_gpt_partitions() function. At first I thought maybe this
> > should be added in fastboot file (fb_mmc.c) but couldn't think of a good
> > reason why this shouldn't happened in part_efi directly.
> >
> > Let me know if you have any questions.
> >
> > Regards,
> > Gary
> > ---
> >  disk/part_efi.c | 3 +++
> >  1 file changed, 3 insertions(+)
> >
> > diff --git a/disk/part_efi.c b/disk/part_efi.c
> > index 2f922662e6e..7a24e33d189 100644
> > --- a/disk/part_efi.c
> > +++ b/disk/part_efi.c
> > @@ -867,6 +867,9 @@ int write_mbr_and_gpt_partitions(struct blk_desc *dev_desc, void *buf)
> >  		return 1;
> >  	}
> >
> > +	/* Update the partition table entries*/
> > +	part_init(dev_desc);
> > +
> >  	return 0;
> >  }
> >  #endif
> >
> 
> This change is for GPT only. Don't we need the same for MBR partition
> tables (write_mbr_partitions())?

I actually have another commit for the MBR partition[1], I just wanted
to send the GPT one first to see if it was an acceptable approach.

Regards,
Gary

[1] https://github.com/boundarydevices/u-boot-imx6/commit/5fc23bce

[PATCH] disk: part_efi: update partition table entries after write

[AKASHI Takahiro]

On Tue, Jan 26, 2021 at 04:08:13PM +0100, Heinrich Schuchardt wrote:
> On 26.01.21 14:56, Gary Bisson wrote:
> > Fixes fastboot issues when switching from mbr to gpt partition tables.
> >
> > Signed-off-by: Gary Bisson <gary.bisson@boundarydevices.com>
> > ---
> > Hi,
> >
> > I hesitated calling this a RFC as I'm not sure everyone will like the
> > idea.
> >
> > Basically the issue encountered was the following:
> > - Device with its storage flashed with a MBR partition table
> > - Run fastboot to flash a new OS (and new partition table)
> > - After flashing a GPT partition table, U-Boot couldn't find any of the
> >   partition names from the GPT
> >   -> reason is that the partition table entries aren't updated
> >   -> so U-Boot still believes it's a MBR table inside and so its parsing
> >   fails
> >
> > This commit adds an update of the table entries inside the
> > write_mbr_and_gpt_partitions() function. At first I thought maybe this
> > should be added in fastboot file (fb_mmc.c) but couldn't think of a good
> > reason why this shouldn't happened in part_efi directly.
> >
> > Let me know if you have any questions.
> >
> > Regards,
> > Gary
> > ---
> >  disk/part_efi.c | 3 +++
> >  1 file changed, 3 insertions(+)
> >
> > diff --git a/disk/part_efi.c b/disk/part_efi.c
> > index 2f922662e6e..7a24e33d189 100644
> > --- a/disk/part_efi.c
> > +++ b/disk/part_efi.c
> > @@ -867,6 +867,9 @@ int write_mbr_and_gpt_partitions(struct blk_desc *dev_desc, void *buf)
> >  		return 1;
> >  	}
> >
> > +	/* Update the partition table entries*/
> > +	part_init(dev_desc);
> > +
> >  	return 0;
> >  }
> >  #endif
> >
> 
> This change is for GPT only. Don't we need the same for MBR partition
> tables (write_mbr_partitions())?
> 
> @Simon:
> 
> Essentially this reflashing is similar to changing media. What I am
> missing in part_init() is setting a field with a counter to indicate the
> media change. The EFI_BLOCK_IO_PROTOCOL has a u32 field media_id. Would
> struct blk_desc be the right place to add such a field.

As far as "efi_loader" is concerned, none of partitions on the media,
either in case of repartitioning or changing media, will no longer be
recognized as a "efi disk" after efi subsystem is initialized.
All we can and have to do is to just reboot the system.

I think we should take one step further to fixing the issue along with
this patch. I have posted a couple of proposals in the past, for example,
see [1].

[1] https://lists.denx.de/pipermail/u-boot/2019-January/356499.html

-Takahiro Akashi

> Best regards
> 
> Heinrich
> 

[PATCH] disk: part_efi: update partition table entries after write

[Heinrich Schuchardt]

On 1/27/21 7:33 AM, AKASHI Takahiro wrote:
> On Tue, Jan 26, 2021 at 04:08:13PM +0100, Heinrich Schuchardt wrote:
>> On 26.01.21 14:56, Gary Bisson wrote:
>>> Fixes fastboot issues when switching from mbr to gpt partition tables.
>>>
>>> Signed-off-by: Gary Bisson <gary.bisson@boundarydevices.com>
>>> ---
>>> Hi,
>>>
>>> I hesitated calling this a RFC as I'm not sure everyone will like the
>>> idea.
>>>
>>> Basically the issue encountered was the following:
>>> - Device with its storage flashed with a MBR partition table
>>> - Run fastboot to flash a new OS (and new partition table)
>>> - After flashing a GPT partition table, U-Boot couldn't find any of the
>>>    partition names from the GPT
>>>    -> reason is that the partition table entries aren't updated
>>>    -> so U-Boot still believes it's a MBR table inside and so its parsing
>>>    fails
>>>
>>> This commit adds an update of the table entries inside the
>>> write_mbr_and_gpt_partitions() function. At first I thought maybe this
>>> should be added in fastboot file (fb_mmc.c) but couldn't think of a good
>>> reason why this shouldn't happened in part_efi directly.
>>>
>>> Let me know if you have any questions.
>>>
>>> Regards,
>>> Gary
>>> ---
>>>   disk/part_efi.c | 3 +++
>>>   1 file changed, 3 insertions(+)
>>>
>>> diff --git a/disk/part_efi.c b/disk/part_efi.c
>>> index 2f922662e6e..7a24e33d189 100644
>>> --- a/disk/part_efi.c
>>> +++ b/disk/part_efi.c
>>> @@ -867,6 +867,9 @@ int write_mbr_and_gpt_partitions(struct blk_desc *dev_desc, void *buf)
>>>   		return 1;
>>>   	}
>>>
>>> +	/* Update the partition table entries*/
>>> +	part_init(dev_desc);
>>> +
>>>   	return 0;
>>>   }
>>>   #endif
>>>
>>
>> This change is for GPT only. Don't we need the same for MBR partition
>> tables (write_mbr_partitions())?
>>
>> @Simon:
>>
>> Essentially this reflashing is similar to changing media. What I am
>> missing in part_init() is setting a field with a counter to indicate the
>> media change. The EFI_BLOCK_IO_PROTOCOL has a u32 field media_id. Would
>> struct blk_desc be the right place to add such a field.
>
> As far as "efi_loader" is concerned, none of partitions on the media,
> either in case of repartitioning or changing media, will no longer be
> recognized as a "efi disk" after efi subsystem is initialized.
> All we can and have to do is to just reboot the system.
>
> I think we should take one step further to fixing the issue along with
> this patch. I have posted a couple of proposals in the past, for example,
> see [1].
>
> [1] https://lists.denx.de/pipermail/u-boot/2019-January/356499.html

We have a deficiency in the UEFI sub-system with adding and removing
block devices. But this is not a problem of Gary's patch.

So from my side:

Reviewed-by: Heinrich Schuchardt <xypron.glpk@gmx.de>