Re: [PATCH 3/9] midx: mark bad packed objects
- From
Derrick Stolee <stolee@gmail.com>
- Date
- Aug 21, 2018, 13:53 UTC
- Message-ID
- <da0185cf-7d48-862b-eb25-5d5bd8f4e833@gmail.com>
- In-Reply-To
- <CAGZ79kY8i3y6_r=bQAx7V5=ckSmb_RgyByjJwtS+7Qr2y8x8LQ@mail.gmail.com>
On 8/20/2018 5:23 PM, Stefan Beller wrote:
Show 12 quoted lines
> On Mon, Aug 20, 2018 at 9:52 AM Derrick Stolee <dstolee@microsoft.com> wrote: >> When an object fails to decompress from a pack-file, we mark the object >> as 'bad' so we can retry with a different copy of the object (if such a >> copy exists). >> >> Before now, the multi-pack-index did not update the bad objects list for >> the pack-files it contains, and we did not check the bad objects list >> when reading an object. Now, do both. > This sounds like a bug fix unlike patches 1 & 2 that sound like > feature work(2) or making code more readable(1). > (After studying the code, this doesn't sound like a bug fix any more, > but a safety thing)
It is a safety thing. One codepath that needs this includes this comment:
/* * We're probably in deep shit, but let's try to fetch * the required base anyway from another pack or loose. * This is costly but should happen only in the presence * of a corrupted pack, and is better than failing outright. */
This goes back to 8eca0b47: implement some resilience against pack corruptions. The logic is tested in t5303-pack-corruption-resilience.sh, with the test title '... and a redundant pack allows for full recovery too'.
> Is it worth having this on a separate track coming in > faster than the rest of this series?
ds/multi-pack-index is cooking in 'next' until after 2.19.0, so I'm not sure it's worth splitting things up at this point.
Show 18 quoted lines
>> Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
>> ---
>> midx.c | 10 ++++++++++
>> 1 file changed, 10 insertions(+)
>>
>> diff --git a/midx.c b/midx.c
>> index 6824acf5f8..7fa75a37a3 100644
>> --- a/midx.c
>> +++ b/midx.c
>> @@ -280,6 +280,16 @@ static int nth_midxed_pack_entry(struct multi_pack_index *m, struct pack_entry *
>> if (!is_pack_valid(p))
>> return 0;
>>
>> + if (p->num_bad_objects) {
>> + uint32_t i;
> Is there a reason that i needs to be if 32 bits?
> Would size_t (for iterating) or 'int' (as a default
> like in many for loops) be ok, too?i is bounded by p->num_bad_objects, which is also uint32_t.
Thanks,
-Stolee