This PR fixes possible leaks that may emanate from not
listening on context cancelation or timeouts.
```
goroutine 60957610 [chan send, 16 minutes]:
github.com/minio/minio/cmd.(*erasureServerPools).Walk.func1.1.1(...)
github.com/minio/minio/cmd/erasure-server-pool.go:1724 +0x368
github.com/minio/minio/cmd.listPathRaw({0x4a9a740, 0xc0666dffc0},...
github.com/minio/minio/cmd/metacache-set.go:1022 +0xfc4
github.com/minio/minio/cmd.(*erasureServerPools).Walk.func1.1()
github.com/minio/minio/cmd/erasure-server-pool.go:1764 +0x528
created by github.com/minio/minio/cmd.(*erasureServerPools).Walk.func1
github.com/minio/minio/cmd/erasure-server-pool.go:1697 +0x1b7
```
The bottom line is delete markers are a nuisance,
most applications are not version aware and this
has simply complicated the version management.
AWS S3 gave an unnecessary complication overhead
for customers, they need to now manage these
markers by applying ILM settings and clean
them up on a regular basis.
To make matters worse all these delete markers
get replicated as well in a replicated setup,
requiring two ILM settings on each site.
This PR is an attempt to address this inferior
implementation by deviating MinIO towards an
idempotent delete marker implementation i.e
MinIO will never create any more than single
consecutive delete markers.
This significantly reduces operational overhead
by making versioning more useful for real data.
This is an S3 spec deviation for pragmatic reasons.
Queue failed/pending replication for healing during listing and GET/HEAD
API calls. This includes healing of existing objects that were never
replicated or those in the middle of a resync operation.
This PR also fixes a bug in ListObjectVersions where lifecycle filtering
should be done.
The path is marked dirty automatically when healObject() is called, which is
wrong. HealObject() is called during self-healing and this will lead to
an increase in the false positive result of the bloom filter.
Also move NSUpdated() from renameData() and call it directly in
CompleteMultipart and PutObject, this is not a functional change but
it will make it less prone to errors in the future.
This PR changes the handling of bucket deletes for site
replicated setups to hold on to deleted bucket state until
it syncs to all the clusters participating in site replication.
The current code uses approximation using a ratio. The approximation
can skew if we have multiple pools with different disk capacities.
Replace the algorithm with a simpler one which counts data
disks and ignore parity disks.
Erasure SD DeleteObjects() is only inheriting bucket versioning status
from the handler layer.
Add the missing versioning prefix evaluation for each object that will
deleted.
We need to make sure if we cannot read bucket metadata
for some reason, and bucket metadata is not missing and
returning corrupted information we should panic such
handlers to disallow I/O to protect the overall state
on the system.
In-case of such corruption we have a mechanism now
to force recreate the metadata on the bucket, using
`x-minio-force-create` header with `PUT /bucket` API
call.
Additionally fix the versioning config updated state
to be set properly for the site replication healing
to trigger correctly.
Main motivation is move towards a common backend format
for all different types of modes in MinIO, allowing for
a simpler code and predictable behavior across all features.
This PR also brings features such as versioning, replication,
transitioning to single drive setups.
