Handling notification in a synchronous manner may lead to a blocking state
if a handler uses neo-go client.
Signed-off-by: Pavel Karpy <carpawell@nspcc.ru>
Return listen errors in a synchronous fashion.
Another solution would be to use buffered channel, but this is not
scalable: for each new similar runner we would need to extend the
buffer.
Signed-off-by: Evgenii Stratonikov <evgeniy@morphbits.ru>
After a4adb79db new logical error could be returned. Do not increase
error counter in this case.
Signed-off-by: Evgenii Stratonikov <evgeniy@morphbits.ru>
Also, try to fetch object header info from the local storage to find as much
object info as possible for the requests which do not assume returning
object header as a response.
Signed-off-by: Pavel Karpy <carpawell@nspcc.ru>
If metabase can't be opened in the default mode, try opening shard
first in `ReadOnly` mode and then in `DegradedReadOnly`.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
Signed-off-by: Evgenii Stratonikov <evgeniy@nspcc.ru>
`Degraded` mode can be set by the administrator if needed.
Modifying operations in this mode can lead node into an inconsistent state
because metabase checks such as lock checking are not performed.
Signed-off-by: Evgenii Stratonikov <evgeniy@nspcc.ru>
There is a need to support working w/o shard if it has problems with
blobovnicza tree.
Make `BlobStor.Init` to return new `ErrInitBlobovniczas` error. Remove
shard from storage engine's shard set if it returned this error from
`Init` call. So if some of the shards (but not all) return this error,
the node will be able to continue working without them.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
Signed-off-by: Evgenii Stratonikov <evgeniy@nspcc.ru>
Reduce public interface of this package. Later each result will contain
an additional status, so it makes more sense to use the same functions
and result processing everywhere.
Signed-off-by: Evgenii Stratonikov <evgeniy@nspcc.ru>
Do not check that a node indeed belongs to the container, because the
synchronization will fail in this case anyway.
Signed-off-by: Evgenii Stratonikov <evgeniy@nspcc.ru>
1. Modifying operations are not expected to fail, unless the shard is
read-only.
2. `Get*` operations should increase error counter too, unless the
error is `ErrTreeNotFound`.
Signed-off-by: Evgenii Stratonikov <evgeniy@nspcc.ru>
Do not return backend type from the service for now, because memory
backend is expected to vanish.
Signed-off-by: Evgenii Stratonikov <evgeniy@nspcc.ru>
The tricky part here is the engine itself: we stop iteration on
`ErrReadOnly` because it is better to synchronize the shard later than
to have partial trees stored in 2 shards.
Signed-off-by: Evgenii Stratonikov <evgeniy@nspcc.ru>
Current implementation prevents invalid operations to become valid at
some later point (consider adding a child to the non-existent parent and
then adding the parent). This seems to diverge from the paper algorithm
and complicates implementation. Make it simpler.
Signed-off-by: Evgenii Stratonikov <evgeniy@nspcc.ru>
In case node is down or failing for some reason, we can expect `Dial` to
fail. In case we actively try to replicate and `Dial` always takes 2
seconds, replication-related channels quickly become full. That affects
latency of all other write operations.
Signed-off-by: Evgenii Stratonikov <evgeniy@nspcc.ru>
Before this commit the replication channel was quickly filled under
heavy load. This lead to the continuously increasing latency for all
write operations. Now it looks better.
Signed-off-by: Evgenii Stratonikov <evgeniy@nspcc.ru>
Also fix a bug with replicator using the multiaddress instead of
<host>:<port> format expected by gRPC library.
Signed-off-by: Evgenii Stratonikov <evgeniy@nspcc.ru>
Currently to find a node by path we iterate over all the children on
each level. This is far from optimal and scales badly with the number of
nodes on a single level. Thus we introduce "indexed attributes" for
which an additional information is stored and which can be use in
`*ByPath` operations. Currently this set only includes `FileName`
attribute but this may change in future.
Signed-off-by: Evgenii Stratonikov <evgeniy@nspcc.ru>
Consider a node `{FileName: "dir", Attribute: "xxx"}`. In case we add
a new node by path `["dir", "file.txt"]`, create a new intermediate node
with a single attribute.
`GetByPath` now also considers only nodes with a single attribute while building a path.
Signed-off-by: Evgenii Stratonikov <evgeniy@nspcc.ru>
In this commit we implement algorithm for CRDT trees from
https://martin.klepmann.com/papers/move-op.pdf
Each tree is identified by the ID of a container it belongs to
and the tree name itself. Essentially, it is a sequence of operations
which should be applied in chronological order to get a usual tree
representation.
There are 2 backends for now: bbolt database and in-memory.
In-memory backend is here for debugging and will eventually act
as a memory-cache for the on-disk database.
Signed-off-by: Evgenii Stratonikov <evgeniy@nspcc.ru>
Replace `ErrRangeOutOfBounds` error from `pkg/core/object` package with
`ObjectOutOfRange` from `apistatus` package. That error is returned by
storage node's server as NeoFS API statuses.
Signed-off-by: Pavel Karpy <carpawell@nspcc.ru>
Shard is intended to be used as a separate failure domain,
which usually resides on a separate disk. Thus, sequential
initialization is bound by IO and this change speeds up thing a bit.
Signed-off-by: Evgenii Stratonikov <evgeniy@nspcc.ru>
Do not calculate and do not write homomorphic hash for containers that were
configured to store objects without hash.
Signed-off-by: Pavel Karpy <carpawell@nspcc.ru>
Do not use homomorphic hash in storage group for containers that have
`homomorphic_hashing_disabled` set to `true`.
Signed-off-by: Pavel Karpy <carpawell@nspcc.ru>
If the container ID is not nil and not equal to the container ID in the
request, consider bearer token invalid.
See also nspcc-dev/neofs-api#207.
Signed-off-by: Evgenii Stratonikov <evgeniy@nspcc.ru>
Allocate memory only if a node chosen as the forwarded request receiver
has responded with a successful status.
Signed-off-by: Pavel Karpy <carpawell@nspcc.ru>
After fixing version fields in forwarded requests, a node does not check
statuses since errors are not covered by direct call error checks.
Signed-off-by: Pavel Karpy <carpawell@nspcc.ru>
Error checkers now support wrapped errors so there is no need to
explicitly unwrap errors in `Policer`.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
Forwarded requests contained zero version in their meta header. It did not
allow responding with API statuses (`v0.0` version considered to be older
than `v2.11`) to the forwarding node and, therefore, did not allow analyzing
responses.
Signed-off-by: Pavel Karpy <carpawell@nspcc.ru>
`auditor` does not need to request SG: processor will fetch that info before
audit context initialization.
Signed-off-by: Pavel Karpy <carpawell@nspcc.ru>
That allows using `ClientCache` for storage group searching before task
context is initialized. Also, that makes it more general purpose.
Signed-off-by: Pavel Karpy <carpawell@nspcc.ru>
Do not use `Marshal()` with object's payload. Use `ReadFromObject` func from
SDK instead. That allows checking both attributes and SG body's expiration
epoch.
Signed-off-by: Pavel Karpy <carpawell@nspcc.ru>
After recent changes in NeoFS SDK Go library session tokens aren't
embedded into `container.Container` and `eacl.Table` structures.
Group value, session token and signature in a structure for container
and eACL.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
The main problem is to distinguish the case of initial initialization
and update from version 0. We can't do this at `Open`, because of
`resync_metabase` flag. Thus, the following approach was taken:
1. During `Open` check whether the metabase was initialized.
2. Check for the version in `Init` or write the new one if the metabase
is new.
3. Update version in `Reset`.
Signed-off-by: Evgenii Stratonikov <evgeniy@nspcc.ru>
After recent changes `buildContainer` method returns two-dimensional
slice of `NodeInfo` so there is no need to flatten it to build slice of
`common.NodeInfo`.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
Make `ReadNetworkConfiguration` method to return `NetworkConfiguration`
by value in order to follow storage engine improvements and prevent heap
escaping.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
`Netmap` contract exports enumeration of the node states.
Replace using literals and constants from NeoFS API Go V2 with the
values provided by contract.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
Cache object that are being processed. That prevents concurrent
object handling when there is a few number of objects and object handling
takes more time that the policer needs for starting that object handling one
more time.
Signed-off-by: Pavel Karpy <carpawell@nspcc.ru>
If placement contains two vectors with intersecting nodes it was possible to
send the object to the nodes twice.
Also optimizes requests: do not ask about storing the object twice from the
same node.
Signed-off-by: Pavel Karpy <carpawell@nspcc.ru>
The node does not support asynchronous object replication anymore, so it
does not need to have replicator worker, channel and `AddTask` function.
Signed-off-by: Pavel Karpy <carpawell@nspcc.ru>
In case we have lots of objects in a single container,
`GetContainerNodes` invoked indirectly by a policer can be seen in
pprof.
Signed-off-by: Evgenii Stratonikov <evgeniy@nspcc.ru>
In previous implementation `verifySignature` method of container
processor worked incorrectly for operations without a key and with
session: processor tried to verify signature with one of the bound owner
keys instead of session one.
Use `VerifySessionDataSignature` method to check the signature if
session is used. Refactor `verifySignature` a bit with session check
highlighting for readability.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
In order to extend container ACL `F` bit must be set in basic ACL.
Make `Container` contract processor to deny eACL tables bound to
non-extendable containers.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
Log errors for network operations. The only places where we are not
interested in errors are `Submit` in pool and unmarshaling.
Signed-off-by: Evgenii Stratonikov <evgeniy@nspcc.ru>
Node shouldn't perform eACL verification during GET/HEAD request
processing until full object header is received. Otherwise, for some
eACL tables request may be falsely rejected.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
Scenario:
* HEAD request of some object
* 1st eACL record allows op for objects with specific user attribute
* 2nd eACL record forbids op by object ID
* node doesn't store the requested object locally
With this scenario node shouldn't deny request.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
It is redundant to process object headers in responses w/o object field
since result will be the same.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
Request processing should not be interrupted in case of local storage
failure since error case in normal for relay nodes.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
ACL service should not deny request on local storage failure since in
this case relay nodes won't be able to continue the operation.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
It is useless process since subnet owner is able to delete subnet without an
Alphabet approval. The Alphabet should only validate netmap state after
removal:
1. Update nodes' attributes if they were included in the deleted subnet;
2. Remove nodes without any subnet entrance.
Signed-off-by: Pavel Karpy <carpawell@nspcc.ru>
`log.With` is suitable during initialization, but in other places it induces
some overhead, even when branches with logging are not taken.
Signed-off-by: Evgenii Stratonikov <evgeniy@nspcc.ru>
If we should process address based on some condition, there is no need
to read file content in memory.
Signed-off-by: Evgenii Stratonikov <evgeniy@nspcc.ru>
Currently we use `(*bbolt.Bucket).Stats().KeyN` for estimating database
size. However, it iterates over all pages in bucket and thus heavily
depends on the bucket size. This commit replaces initial size estimation
with a single `os.Stat` call.
Signed-off-by: Evgenii Stratonikov <evgeniy@nspcc.ru>
Core changes:
* avoid package-colliding variable naming
* avoid using pointers to IDs where unnecessary
* avoid using `idSDK` import alias pattern
* use `EncodeToString` for protocol string calculation and `String` for
printing
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
Helper function `client.IsErrObjectNotFound` doesn't support error
unwrapping, so we need to do it on caller side.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
`Policer` should pass list of selected candidates into `WithNodes`
method of `replicator.Task`. In previous implementation `processNodes`
method passed an opposite list: failed nodes and/or the local one.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
Not all the NeoFS requests must contain OID in their bodies (or must NOT
contain them at all). Do not pass object address in helper functions, pass
CID and OID separately instead.
Also, fixed NPE in the ACL service: updated SDK library brought errors
when working with `Put` and `Search` requests without OID fields.
Signed-off-by: Pavel Karpy <carpawell@nspcc.ru>
In previous implementation `Policer` considered local object copy as
redundant on processing single placement vector.
Make `Policer` to call redundant copy callback after full placement
processing. Also fix 404 error parsing.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
Call `UpdateStateIR` and `AddPeerIR` method instead of `UpdateState` and
`AddPeer` if calling client is configured as Alphabet in notary enabled
environment.
Signed-off-by: Pavel Karpy <carpawell@nspcc.ru>
Parse all headers beforehand and reject invalid requests.
Another approach would be to remember the error and check
it after `CalculateAction`, which is a bit faster.
The rule of thumb here is "first validate, then use".
Signed-off-by: Evgenii Stratonikov <evgeniy@nspcc.ru>
It is nice to have different paths for different components and also
check that the information returned is different for different shards.
Signed-off-by: Evgenii Stratonikov <evgeniy@nspcc.ru>
In previous implementation NeoFS CLI app used `network.Address.HostAddr`
as a server URI, which caused scheme loss since host address doesn't
contain it.
Rename `HostAddr` to `URIAddr` and make it to return URI address with
`grpcs` scheme if TLS is enabled. Make `TLSEnabled` unexported since it
was used to provide default `tls.Config` only (it is used by default in
SDK).
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
- Delete objects physically on tombstone's arrival;
- Store information about tombstones in the Graveyard;
- Clear Graveyard every epoch based on the information about TS in the
network.
Signed-off-by: Pavel Karpy <carpawell@nspcc.ru>
The service fetches tombstones from the network via object service, every
request is handled in the following order:
1. checks local LRU cache;
2. checks local storage engine;
3. tries to find object in the placement nodes.
Signed-off-by: Pavel Karpy <carpawell@nspcc.ru>
Add offset element to the iterations over deleted objects (both the
Graveyard and the Garbage buckets).
Signed-off-by: Pavel Karpy <carpawell@nspcc.ru>
It allows storing information about object in both ways at the same time:
1. Metabase should know if an object is covered by a tombstone (that is
not expired yet);
2. It should be possible to physically delete objects covered by a
tombstone immediately (mark with GC) but keep tombstone knowledge.
Signed-off-by: Pavel Karpy <carpawell@nspcc.ru>
Morph "NewEpoch" event handling was registered in a closure over
`addNewEpochNotificationHandler` func. That may lead to the data race:
if a shard was initialized before the event registration, everything works
as planned, but if registration was made earlier, it was not able to
include GC handlers since a shard has not called `eventChanInit` yet and,
therefore, it has not registered handler yet.
Signed-off-by: Pavel Karpy <carpawell@nspcc.ru>
Add worker pool to the listener to prevent blocking. It is used only for
notary notifications and new block events handling since it uses RPC
calls. That may lead to the deadlock state: neo-go cannot send RPC until
notification channel is read but notification channel cannot be read since
neo-go client cannot send RPC.
Signed-off-by: Pavel Karpy <carpawell@nspcc.ru>
Updated client now supports subscription to chain notifications and RPC
switch between provided RPC endpoints.
Signed-off-by: Pavel Karpy <carpawell@nspcc.ru>
Provide current heights as an argument to ticker.
Zero height disables any checks, thus corresponding to the old
behaviour. If non-zero height is used, ignore the tick if the height
is less than the timer tick state.
Signed-off-by: Evgenii Stratonikov <evgeniy@nspcc.ru>
After `Listen` has raw receiver and calls `listen` which has pointer
receiver, leading to ineffectual assign to `started` field.
Always use `listener` by pointer, to avoid similar bugs.
Signed-off-by: Evgenii Stratonikov <evgeniy@nspcc.ru>
When IR node configured without main chain, both
`morphListener` and `mainnetListener` are pointing
into single listener component. We should not call
`Stop()` twice, because it may trigger channel
closing in neo-go or other components and it
can throw panic.
Signed-off-by: Alex Vanin <alexey@nspcc.ru>
Prevent attemts to connect to the failing endpoint multiple times.
This speeds up all invocations a bit and removes excessive error logs.
Signed-off-by: Evgenii Stratonikov <evgeniy@nspcc.ru>
Also, remove optimization comments:
1. Having to maintain an execute the same logic for headers as for
objects is quite inefficient, as it increases memory footprint.
2. Unmarshaling object is a cheap operation if data slice is in memory.
3. For unmarshaling header-only, I think we need SDK support.
Signed-off-by: Evgenii Stratonikov <evgeniy@nspcc.ru>
`Degraded` mode is set automatically after error counter is over the
threshold. `ReadOnly` mode can still be set by an administrator.
Signed-off-by: Evgenii Stratonikov <evgeniy@nspcc.ru>
Add `WithEncryption` option that passes ECDSA key to the persistent session
storage. It uses 32 bytes from marshalled ECDSA key in ASN.1 DER from in
AES-256 algorithm encryption in Galois/Counter Mode.
Signed-off-by: Pavel Karpy <carpawell@nspcc.ru>
Move in-memory session storage to the separate directory of `storage`. It is
done for future support of different kind of session storages.
Signed-off-by: Pavel Karpy <carpawell@nspcc.ru>
`Batch` can execute the function multiple times leading to multiple
increases of a size approximation.
Signed-off-by: Evgenii Stratonikov <evgeniy@nspcc.ru>
Alphabet nodes in notary enabled environment cannot call `UpdateState`
method to remove unwanted storage nodes from the network map,
because this method checks witness of the storage node.
To force storage node state update, alphabet nodes should invoke
new method `UpdateStateIR` which is similar to `AddPeerIR`.
State update initiated by the storage node itself is processed
the same way as before -- alphabet nods resign such transaction.
Signed-off-by: Alex Vanin <alexey@nspcc.ru>
`Register` was renamed to `AddPeerIR` for consistency with
`UpdateState` changes in
https://github.com/nspcc-dev/neofs-contract/pull/227
This is protocol breaking change for notary enabled environment.
Luckily, there is no notary enabled environments anywhere except
of neofs-dev-env, so we can do such thing. We should avoid such
changes in the future, though.
Signed-off-by: Alex Vanin <alexey@nspcc.ru>
`apistatus` package provides types which implement build-in `error`
interface. Add `error of type` pattern when documenting these errors in
order to clarify how these errors should be handled (e.g. `errors.Is` is
not good).
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
Return `apistatus.ObjectAccessDenied` error on access violation from ACL
service. Write reason in format of the errors from the previous
implementation. These errors are returned by storage node's server as
NeoFS API statuses.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
Replace `core/container.ErrNotFound` error returned by `Source.Get`
interface method with `apistatus.ContainerNotFound` status error. This
error is returned by storage node's server as NeoFS API statuses.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
Replace `ErrNotFound`/`ErrAlreadyRemoved` error from
`pkg/core/object` package with `ObjectNotFound`/`ObjectAlreadyRemoved`
one from `apistatus` package. These errors are returned by storage
node's server as NeoFS API statuses.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
Return `SessionTokenExpired`/`SessionTokenNotFound` error from
`apistatus` package if private session token is expired/missing. These
errors are returned by storage node's server as NeoFS API statuses.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
Make all epoch independent in reputation process. Do not reset any timers
related to reputation. Make it possible to finish iteration after the
unexpected `NewEpoch` event.
Signed-off-by: Pavel Karpy <carpawell@nspcc.ru>
There is a need to process expired `LOCK` objects similar to `TOMBSTONE`
ones: we collect them on `Shard`, notify all other shards about
expiration so they could unlock the objects, and only after that mark
lockers as garbage.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
In previous implementation `SignService` converted all `error` values to
`INTERNAL` server failure status. That was done for simplification only.
There is a need to transmit status errors as corresponding status
messages.
Make `SignService` to unwrap errors and convert them to status message
during writing to the response. Non-status errors are converted to
`INTERNAL` server failures. Status errors can also be wrapped in the
depths of the executable code, so `SignService` tries to unwrap them.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
Make `FormatValidator.ValidateContent` to verify payload of `LOCK`
objects. Pass locked objects to `Locker` interface. Require from
`Locker.Lock` to return `apistatus.IrregularObjectLock` error on a
corresponding condition.
Also add error return to `DeleteHandler.DeleteObjects` method. Require
from method to return `apistatus.ObjectLocked` error on a corresponding
condition. Adopt implementations.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
`Inhume` operation can potentially mark lockers as garbage. There is a
need to update locker list in locked bucket.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
Make `StorageEngine.Delete` to forward first encountered
`apistatus.ObjectLocked` error during shard processing.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
Make `StorageEngine.Inhume` to forward first encountered
`apistatus.ObjectLocked` error during shard processing.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
Implement `StorageEngine.Lock` method which works similar to `Inhume`
but calls `Lock` on the processing shards.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
Make `DB.Lock` to return `apistatus.IrregularObjectLock` if at least one
of the locked objects is irregular (not of type REGULAR).
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
Make `DB.Inhume` to return `apistatus.ObjectLocked` if at least one of
the inhumed objects is locked.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
Make `DB.IterateCoveredByTombstones` to not pass locked objects to the
handler. The method is used by GC, therefore it will not consider locked
objects as candidates for deletion even if their tombstone is expired.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
Make `DB.IterateExpired` to not pass locked objects to the handler. The
method is used by GC, therefore it will not consider them as candidates
for deletion.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
After introduction of LOCK objects (of type `TypeLock`) complicated
extended its behavior:
* create `lockers` container bucket (LCB) during PUT;
* remove object from LCB during DELETE;
* look up object in LCB during EXISTS;
* get object from LCB during GET;
* list objects from LCB during LIST with cursor;
* select objects from LCB during SELECT with '*'.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
Implement `DB.Lock` method which marks list of the objects as locked by
another object. Only regular objects can be locked.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
Create class of container buckets with `LOCKED` suffix. Put identifiers
of the objects of type `LOCK` to these buckets during `DB.Put`.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
After `putsvc.Service` started to support additional container broadcast
of the saved objects there is no more need to perform broadcast of
tombstone object in `deletesvc.Service`.
Make `putsvc.Service` to perform additional broadcast of `TOMBSTONE`
objects. Remove `broadcastTombstone` stage from `deletesvc.execCtx`,
from now it is encapsulated in `saveTombstone` stage. Remove no longer
needed `putsvc.PutInitPrm.WithTraverseOption` method.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
There are several cases when we need to spread the object around the
container after its primary placement (e.g. objects of type TOMBSTONE).
It'd be convenient to support this feature in `putsvc.Service`.
Add additional stage of container broadcast after the object is stored.
This stage is carried out no more than once and does not affect the
outcome of the main PUT operation.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
