[PATCHv2 7/9] UBIFS: do not write rubbish into truncation scanning node

[Adrian Hunter]

Adrian Hunter wrote:
> Artem Bityutskiy wrote:
>> From: Artem Bityutskiy <Artem.Bityutskiy at nokia.com>
>>
>> In the scanning code, in 'ubifs_add_snod()', we write rubbish into
>> 'snod->key', because we assume that on-flash truncation nodes have a key, but
>> they do not. If the other parts of UBIFS then mistakenly try to look-up
>> the truncation node key (they should not do this, but may do because of a bug),
>> we can succeed and corrupt TNC. It looks like we did have such a situation in
>> 'sort_nodes()' in gc.c.
>>
>> Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy at nokia.com>
>> ---
>>  fs/ubifs/scan.c |    1 -
>>  1 files changed, 0 insertions(+), 1 deletions(-)
>>
>> diff --git a/fs/ubifs/scan.c b/fs/ubifs/scan.c
>> index 96c5253..a0a305c 100644
>> --- a/fs/ubifs/scan.c
>> +++ b/fs/ubifs/scan.c
>> @@ -212,7 +212,6 @@ int ubifs_add_snod(const struct ubifs_info *c, struct ubifs_scan_leb *sleb,
>>  	case UBIFS_DENT_NODE:
>>  	case UBIFS_XENT_NODE:
>>  	case UBIFS_DATA_NODE:
>> -	case UBIFS_TRUN_NODE:
> 
> There is another bug in ubifs_recover_size_accum() that expects a truncate node
> to have a key.  That would be fixed by using trun_key_init() here.

No I was wrong, the key in ubifs_recover_size_accum() is already created using
trun_key_init()

Still, trun_key_init might be better here because the all-zeroes key has a key-type
of UBIFS_INO_KEY.  What do you think?

> 
>>  		/*
>>  		 * The key is in the same place in all keyed
>>  		 * nodes.
> 
>