Re: [PATCH 2/3] btrfs: Add csum type check for btrfs_check_super_valid()

[Qu Wenruo <quwenruo.btrfs@gmx.com>]

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On 2018年04月19日 18:09, David Sterba wrote:
> On Thu, Apr 19, 2018 at 05:38:15PM +0800, Qu Wenruo wrote:
>> Just like incompat flags check, although we have already done super csum
>> type check before calling btrfs_check_super_valid(), we can still add
>> such check for later write time check.
>>
>> Signed-off-by: Qu Wenruo <wqu@suse.com>
>> ---
>>  fs/btrfs/disk-io.c | 9 +++++++++
>>  1 file changed, 9 insertions(+)
>>
>> diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
>> index ec123158f051..b189ec086bc2 100644
>> --- a/fs/btrfs/disk-io.c
>> +++ b/fs/btrfs/disk-io.c
>> @@ -3981,6 +3981,15 @@ static int btrfs_check_super_valid(struct btrfs_fs_info *fs_info)
>>  	u64 sectorsize = btrfs_super_sectorsize(sb);
>>  	int ret = 0;
>>  
>> +	/*
>> +	 * For write time check, as for mount time we have checked csum before
>> +	 * calling btrfs_check_super_valid(), so it must be a corruption
>> +	 */
>> +	if (btrfs_super_csum_type(sb) >= ARRAY_SIZE(btrfs_csum_sizes)) {
>> +		btrfs_err(fs_info, "corrupted csum type %u",
>> +			  btrfs_super_csum_type(sb));
>> +		ret = -EINVAL;
>> +	}
>>  	if (btrfs_super_magic(sb) != BTRFS_MAGIC) {
> 
> The test for magic should be IMO the first one, that's how the
> filesystem type is identified before anything else. Granted that the
> magic must be correct before it can be even mounted, but the code should
> follow that logic too. Otherwise ok.

Makes sense, will update the patchset.

Thanks,
Qu

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