21.08.2021 01:45, Michał Mirosław пишет:
> On Thu, Aug 19, 2021 at 01:19:17AM +0300, Dmitry Osipenko wrote:
>> Support looking up GPT at a non-standard location specified by a block
>> device driver.
>>
>> Signed-off-by: Dmitry Osipenko <digetx@xxxxxxxxx>
>> ---
>> block/partitions/efi.c | 12 ++++++++++++
>> 1 file changed, 12 insertions(+)
>>
>> diff --git a/block/partitions/efi.c b/block/partitions/efi.c
>> index aaa3dc487cb5..7ca5c4c374d4 100644
>> --- a/block/partitions/efi.c
>> +++ b/block/partitions/efi.c
>> @@ -585,6 +585,8 @@ static int find_valid_gpt(struct parsed_partitions *state, gpt_header **gpt,
>> gpt_header *pgpt = NULL, *agpt = NULL;
>> gpt_entry *pptes = NULL, *aptes = NULL;
>> legacy_mbr *legacymbr;
>> + struct gendisk *disk = state->disk;
>> + const struct block_device_operations *fops = disk->fops;
>> sector_t total_sectors = get_capacity(state->disk);
>> u64 lastlba;
>>
>> @@ -619,6 +621,16 @@ static int find_valid_gpt(struct parsed_partitions *state, gpt_header **gpt,
>> if (!good_agpt && force_gpt)
>> good_agpt = is_gpt_valid(state, lastlba, &agpt, &aptes);
>>
>> + if (!good_agpt && force_gpt && fops->alternative_gpt_sector) {
>> + sector_t agpt_sector;
>> + int err;
>> +
>> + err = fops->alternative_gpt_sector(disk, &agpt_sector);
>> + if (!err)
>> + good_agpt = is_gpt_valid(state, agpt_sector,
>> + &agpt, &aptes);
>> + }
>> +
>
> When alternative_gpt_sector is provided I would expect it to override
> the default, not be a fallback for it. But if someone tries to put
> a broken (decoy, garbage) GPT at a standard place, current ordering
> will prevent overriding it.
This will break devices that have GPT at standard location. If someone
tries to manipulate with GPT entries, then it's a problem of that someone.
