[#1450] engine: Group object by shard before Inhume

```
goos: linux
goarch: amd64
pkg: git.frostfs.info/TrueCloudLab/frostfs-node/pkg/local_object_storage/engine
cpu: 12th Gen Intel(R) Core(TM) i5-1235U
                                 │   old.txt    │              new.txt                │
                                 │    sec/op    │   sec/op     vs base                │
InhumeMultipart/objects=1-12        11.42m ± 1%   10.71m ± 0%   -6.27% (p=0.000 n=10)
InhumeMultipart/objects=10-12       113.5m ± 0%   100.9m ± 3%  -11.08% (p=0.000 n=10)
InhumeMultipart/objects=100-12     1135.4m ± 1%   681.3m ± 2%  -40.00% (p=0.000 n=10)
InhumeMultipart/objects=1000-12     11.358 ± 0%    1.089 ± 1%  -90.41% (p=0.000 n=10)
InhumeMultipart/objects=10000-12   113.251 ± 0%    1.645 ± 1%  -98.55% (p=0.000 n=10)
geomean                              1.136        265.5m       -76.63%
```

Signed-off-by: Aleksey Savchuk <a.savchuk@yadro.com>

pkg/local_object_storage/engine/inhume.go

@@ -81,110 +81,146 @@ func (e *StorageEngine) Inhume(ctx context.Context, prm InhumePrm) (res InhumeRe
 }
 
 func (e *StorageEngine) inhume(ctx context.Context, prm InhumePrm) (InhumeRes, error) {
+	addrsPerShard, err := e.groupObjectsByShard(ctx, prm.addrs, !prm.forceRemoval)
+	if err != nil {
+		return InhumeRes{}, err
+	}
+
 	var shPrm shard.InhumePrm
 	if prm.forceRemoval {
 		shPrm.ForceRemoval()
 	}
 
-	for i := range prm.addrs {
-		if !prm.forceRemoval {
-			locked, err := e.IsLocked(ctx, prm.addrs[i])
-			if err != nil {
-				e.log.Warn(ctx, logs.EngineRemovingAnObjectWithoutFullLockingCheck,
-					zap.Error(err),
-					zap.Stringer("addr", prm.addrs[i]),
-					zap.String("trace_id", tracingPkg.GetTraceID(ctx)))
-			} else if locked {
-				return InhumeRes{}, new(apistatus.ObjectLocked)
-			}
-		}
+	var errLocked *apistatus.ObjectLocked
 
+	for shardID, addrs := range addrsPerShard {
 		if prm.tombstone != nil {
-			shPrm.SetTarget(*prm.tombstone, prm.addrs[i])
+			shPrm.SetTarget(*prm.tombstone, addrs...)
 		} else {
-			shPrm.MarkAsGarbage(prm.addrs[i])
+			shPrm.MarkAsGarbage(addrs...)
 		}
 
-		ok, err := e.inhumeAddr(ctx, prm.addrs[i], shPrm, true)
-		if err != nil {
-			return InhumeRes{}, err
+		sh, exists := e.shards[shardID]
+		if !exists {
+			e.log.Warn(ctx, logs.EngineCouldNotInhumeObjectInShard,
+				zap.Error(errors.New("this shard was expected to exist")),
+				zap.String("shard_id", shardID),
+				zap.String("trace_id", tracingPkg.GetTraceID(ctx)),
+			)
+			return InhumeRes{}, errInhumeFailure
 		}
-		if !ok {
-			ok, err := e.inhumeAddr(ctx, prm.addrs[i], shPrm, false)
-			if err != nil {
-				return InhumeRes{}, err
-			} else if !ok {
-				return InhumeRes{}, errInhumeFailure
+
+		if _, err := sh.Inhume(ctx, shPrm); err != nil {
+			switch {
+			case errors.As(err, &errLocked):
+			case errors.Is(err, shard.ErrLockObjectRemoval):
+			case errors.Is(err, shard.ErrReadOnlyMode):
+			case errors.Is(err, shard.ErrDegradedMode):
+			default:
+				e.reportShardError(ctx, sh, "couldn't inhume object in shard", err)
 			}
+			return InhumeRes{}, err
 		}
 	}
 
 	return InhumeRes{}, nil
 }
 
-// Returns ok if object was inhumed during this invocation or before.
-func (e *StorageEngine) inhumeAddr(ctx context.Context, addr oid.Address, prm shard.InhumePrm, checkExists bool) (bool, error) {
-	root := false
-	var existPrm shard.ExistsPrm
-	var retErr error
-	var ok bool
+// groupObjectsByShard groups objects based on the shard(s) they are stored on.
+//
+// If checkLocked is set, [apistatus.ObjectLocked] will be returned if any of
+// the objects are locked.
+func (e *StorageEngine) groupObjectsByShard(ctx context.Context, addrs []oid.Address, checkLocked bool) (map[string][]oid.Address, error) {
+	groups := make(map[string][]oid.Address)
+
+	for _, addr := range addrs {
+		ids, err := e.findShards(ctx, addr, checkLocked)
+		if err != nil {
+			return nil, err
+		}
+		for _, id := range ids {
+			groups[id] = append(groups[id], addr)
+		}
+	}
+
+	return groups, nil
+}
+
+// findShards determines the shard(s) where the object is stored.
+//
+// If the object is a root object, multiple shards will be returned.
+//
+// If checkLocked is set, [apistatus.ObjectLocked] will be returned if any of
+// the objects are locked.
+func (e *StorageEngine) findShards(ctx context.Context, addr oid.Address, checkLocked bool) ([]string, error) {
+	var (
+		ids    []string
+		retErr error
+
+		prm shard.ExistsPrm
+
+		siErr *objectSDK.SplitInfoError
+		ecErr *objectSDK.ECInfoError
+
+		isRootObject bool
+		objectExists bool
+	)
 
 	e.iterateOverSortedShards(addr, func(_ int, sh hashedShard) (stop bool) {
-		defer func() {
-			// if object is root we continue since information about it
-			// can be presented in other shards
-			if checkExists && root {
-				stop = false
-			}
-		}()
+		objectExists = false
 
-		if checkExists {
-			existPrm.Address = addr
-			exRes, err := sh.Exists(ctx, existPrm)
-			if err != nil {
-				if client.IsErrObjectAlreadyRemoved(err) || shard.IsErrObjectExpired(err) {
-					// inhumed once - no need to be inhumed again
-					ok = true
-					return true
-				}
-
-				var siErr *objectSDK.SplitInfoError
-				var ecErr *objectSDK.ECInfoError
-				if !(errors.As(err, &siErr) || errors.As(err, &ecErr)) {
-					e.reportShardError(ctx, sh, "could not check for presents in shard", err, zap.Stringer("address", addr))
-					return
-				}
-
-				root = true
-			} else if !exRes.Exists() {
-				return
-			}
+		prm.Address = addr
+		switch res, err := sh.Exists(ctx, prm); {
+		case client.IsErrObjectAlreadyRemoved(err) || shard.IsErrObjectExpired(err):
+			// NOTE(@a-savchuk): there were some considerations that we can stop
+			// immediately if the object is already removed or expired. However,
+			// the previous method behavior was:
+			// - keep iterating if it's a root object and already removed,
+			// - stop iterating if it's not a root object and removed.
+			//
+			// Since my task was only improving method speed, let's keep the
+			// previous method behavior. Continue if it's a root object.
+			return !isRootObject
+		case errors.As(err, &siErr) || errors.As(err, &ecErr):
+			isRootObject = true
+			objectExists = true
+		case err != nil:
+			e.reportShardError(
+				ctx, sh, "couldn't check for presence in shard",
+				err, zap.Stringer("address", addr),
+			)
+		case res.Exists():
+			objectExists = true
+		default:
 		}
 
-		_, err := sh.Inhume(ctx, prm)
-		if err != nil {
-			var errLocked *apistatus.ObjectLocked
-			switch {
-			case errors.As(err, &errLocked):
+		if !objectExists {
+			return
+		}
+
+		if checkLocked {
+			if isLocked, err := sh.IsLocked(ctx, addr); err != nil {
+				e.log.Warn(ctx, logs.EngineRemovingAnObjectWithoutFullLockingCheck,
+					zap.Error(err),
+					zap.Stringer("address", addr),
+					zap.String("trace_id", tracingPkg.GetTraceID(ctx)),
+				)
+			} else if isLocked {
 				retErr = new(apistatus.ObjectLocked)
 				return true
-			case errors.Is(err, shard.ErrLockObjectRemoval):
-				retErr = shard.ErrLockObjectRemoval
-				return true
-			case errors.Is(err, shard.ErrReadOnlyMode) || errors.Is(err, shard.ErrDegradedMode):
-				retErr = err
-				return true
 			}
-
-			e.reportShardError(ctx, sh, "could not inhume object in shard", err, zap.Stringer("address", addr))
-			return false
 		}
 
-		ok = true
-		return true
+		ids = append(ids, sh.ID().String())
+
+		// Continue if it's a root object.
+		return !isRootObject
 	})
 
-	return ok, retErr
+	if retErr != nil {
+		return nil, retErr
+	}
+	return ids, nil
 }
 
 // IsLocked checks whether an object is locked according to StorageEngine's state.