Re: rgw: leak with incomplete multiparts (was: Request for review)

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Hi Penglaiyxy,

I was able to reproduce the scenario described by you in current
master branch. It turns out that, in case of re-uploading a part, rgw
assigns a different prefix to it. This was introduced by the commit
[1] as a fix for racy part uploads [2]. This leads to orphaned parts
being uploaded, which have an entry in bucket index, but are not
really part of any uploaded object. Such orphaned parts should have
ideally been cleaned-up on multipart complete or abort operation. This
looks like a slightly different issue, as the clean-up of such parts
should not wait for a bucket deletion operation to happen.

Can you open a separate tracker issue for this, if one not present already.

[1] https://github.com/ceph/ceph/pull/1781/commits/bd8e026f88b812cc70caf6232c247844df5d99bf
[2] http://tracker.ceph.com/issues/8269

Thanks
Abhishek

On Tue, Jun 13, 2017 at 12:28 PM, 于相洋 <penglaiyxy@xxxxxxxxx> wrote:
> Hi Abhishek,
>
> Your PR is practical  for anyone who can not delete an non-empty bucket.
>
> But I think in one scenario that you still can not delete bucket
> because of the orphan object leaked by multipart upload.
>
> Upload a multipart object:
>
> 1. Upload part 1 with prefix   2~-DUZmxVbiv9dBycBdci2iMhiKEEUv-5
>
> 2. The connection between rgw client and server is cutoff,  I don't
> know if  I have upload part one completely ,so I re-upload part 1 then
> the part 1 is attached with a new prefix like
> eOntuNHW8UdvnpbLl9UAdYGuWrL9HPH(which is tackled by rgw server )
>
> 3. The connection between rgw client and server is cutoff again, then
> I re-upload part 1 with new  prefix d9H1FWnoOwmr3IAejtYQJ2hyIjsUA7U
>
> 4. Upload part 2 and left parts
>
> 5. At the end, complete the upload.
>
> The object with names below is leaked and I can not see them through
> s3 client.  (My upload size is 15MB and stripe size is 4M)
>
> center-master.4439.1__multipart_bigfile.2~-DUZmxVbiv9dBycBdci2iMhiKEEUv-5.1
> center-master.4439.1__shadow_bigfile.2~-DUZmxVbiv9dBycBdci2iMhiKEEUv-5.1_1
> center-master.4439.1__shadow_bigfile.2~-DUZmxVbiv9dBycBdci2iMhiKEEUv-5.1_2
> center-master.4439.1__shadow_bigfile.2~-DUZmxVbiv9dBycBdci2iMhiKEEUv-5.1_3
>
> center-master.4439.1__multipart_bigfile.eOntuNHW8UdvnpbLl9UAdYGuWrL9HPH.1
> center-master.4439.1__shadow_bigfile.eOntuNHW8UdvnpbLl9UAdYGuWrL9HPH.1_1
> center-master.4439.1__shadow_bigfile.eOntuNHW8UdvnpbLl9UAdYGuWrL9HPH.1_2
> center-master.4439.1__shadow_bigfile.eOntuNHW8UdvnpbLl9UAdYGuWrL9HPH.1_3
>
> The above upload process is really occurring in our production
> application and we find a lot space leaked.
>
> How can I reclaim the space leaked?
>
> Any Idea is appreciated.
>
>
> ________________________________
> penglaiyxy
>
> From: Abhishek Varshney
> Date: 2017-06-13 00:17
> To: Ceph Development
> Subject: rgw: leak with incomplete multiparts (was: Request for review)
> Reviving an old thread by a colleague on rgw leaking rados objects,
> the PR submitted earlier [1] had failed teuthology rgw run, due to
> radosgw-admin failing to remove a user with --purge-data flag. I tried
> to root cause the issue, and it turned out that incomplete multiparts
> need to be aborted when doing bucket rm with --purge-data. Here is the
> new PR (https://github.com/ceph/ceph/pull/15630) which handles
> incomplete multiparts with behaviour as given below:
>
> * radosgw-admin user/bucket rm with incomplete multiparts would return
> bucket not empty error.
> * radosgw-admin user/bucket rm --purge-data with incomplete multiparts
> would abort the pending multiparts and then delete the bucket.
> * S3 delete bucket API with incomplete multiparts would return bucket
> not empty error. The expectation here is on the user to either
> complete or cancel all pending multipart uploads before deleting the
> bucket.
>
> Requesting review on this PR.
>
> PS : The check for an empty bucket index here [2] in the previous PR
> [1] has been removed, as we found instances of inconsistent bucket
> index with stale entries, without corresponding objects present in
> data pool. This would have prevented the deletion of an empty bucket
> with such inconsistent indexes. I am not sure on how to reproduce such
> a scenario though.
>
> [1] https://github.com/ceph/ceph/pull/10920
> [2] https://github.com/ceph/ceph/pull/10920/files#diff-c30965955342b98393b73be699f4e355R7349
>
> Thanks
> Abhishek
>
> On Mon, Sep 12, 2016 at 4:23 AM, Praveen Kumar G T (Cloud Platform)
> <praveen.gt@xxxxxxxxxxxx> wrote:
>> Definitions
>>
>> Orphaned Objects: Orphaned objects are created when a Multipart upload has uploaded some or all of the parts but without executing multipart cancel or multipart complete. An incomplete Multipart upload is neither created nor destroyed, it is in orphan state
>> Leaked Objects : Objects that are not deleted on the ceph cluster but assumed to be deleted by s3 client. These objects cannot be accessed by s3 clients but still occupy space in the ceph cluster
>>
>> Problem
>>
>> A s3 bucket cannot be deleted when there are objects in it. The bucket deletion command will fail with error BucketNotEmpty. The objects in the buckets can be listed using any of the s3 clients. In case if we have orphaned objects present in the bucket, they will not be listed via the normal listing operations of the s3 clients. If the bucket is deleted when there are orphaned objects in the bucket, they will end up being leaked. This ends of using space in the ceph cluster even though the objects are not accessed by any of the s3 clients. This space is not accounted under the radosgw user account as well
>>
>> Tracker link
>>
>> http://tracker.ceph.com/issues/17164
>>
>> Fix
>>
>> The fix will avoid deletion of buckets even if there are Orphaned objects in the bucket. So now bucket deletion command will return BucketNotEmpty  when there are orphaned objects as well.
>>
>> Pull request
>>
>> https://github.com/ceph/ceph/pull/10920
>>
>> Can somebody Please review the fix. We have already verified the fix locally.
>>
>> Regards,
>> Praveen.
>>
>>
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