frostfs-node/pkg/local_object_storage/engine/get.go
Evgenii Stratonikov c6af4a3ec8 [#679] engine: Do not increase error counter on meta mismatch
It was introduced in 69e1e6ca to help node determine faulty shards.
However, the situation is possible in a real-life scenario:
1. Object O is evacuated from shard A to B.
2. Shard A is unmounted because of lower-level errors.
3. We now have object in meta on A and in blobstor on B. Technically we
   have it in meta on shard B too, but we still got the error if B goes
   to a degraded mode.

Signed-off-by: Evgenii Stratonikov <e.stratonikov@yadro.com>
2023-09-14 10:39:18 +03:00

208 lines
5.4 KiB
Go

package engine
import (
"context"
"errors"
"git.frostfs.info/TrueCloudLab/frostfs-node/internal/logs"
"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/local_object_storage/shard"
"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/local_object_storage/util"
"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/local_object_storage/util/logicerr"
"git.frostfs.info/TrueCloudLab/frostfs-observability/tracing"
"git.frostfs.info/TrueCloudLab/frostfs-sdk-go/client"
apistatus "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/client/status"
objectSDK "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/object"
oid "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/object/id"
"go.opentelemetry.io/otel/attribute"
"go.opentelemetry.io/otel/trace"
"go.uber.org/zap"
)
// GetPrm groups the parameters of Get operation.
type GetPrm struct {
addr oid.Address
}
// GetRes groups the resulting values of Get operation.
type GetRes struct {
obj *objectSDK.Object
}
// WithAddress is a Get option to set the address of the requested object.
//
// Option is required.
func (p *GetPrm) WithAddress(addr oid.Address) {
p.addr = addr
}
// Object returns the requested object.
func (r GetRes) Object() *objectSDK.Object {
return r.obj
}
// Get reads an object from local storage.
//
// Returns any error encountered that
// did not allow to completely read the object part.
//
// Returns an error of type apistatus.ObjectNotFound if the requested object is missing in local storage.
// Returns an error of type apistatus.ObjectAlreadyRemoved if the object has been marked as removed.
//
// Returns an error if executions are blocked (see BlockExecution).
func (e *StorageEngine) Get(ctx context.Context, prm GetPrm) (res GetRes, err error) {
ctx, span := tracing.StartSpanFromContext(ctx, "StorageEngine.Get",
trace.WithAttributes(
attribute.String("address", prm.addr.EncodeToString()),
))
defer span.End()
err = e.execIfNotBlocked(func() error {
res, err = e.get(ctx, prm)
return err
})
return
}
func (e *StorageEngine) get(ctx context.Context, prm GetPrm) (GetRes, error) {
if e.metrics != nil {
defer elapsed("Get", e.metrics.AddMethodDuration)()
}
errNotFound := new(apistatus.ObjectNotFound)
var shPrm shard.GetPrm
shPrm.SetAddress(prm.addr)
it := &getShardIterator{
OutError: errNotFound,
ShardPrm: shPrm,
Address: prm.addr,
Engine: e,
}
it.tryGetWithMeta(ctx)
if it.SplitInfo != nil {
return GetRes{}, logicerr.Wrap(objectSDK.NewSplitInfoError(it.SplitInfo))
}
if it.ObjectExpired {
return GetRes{}, errNotFound
}
if it.Object == nil {
if !it.HasDegraded && it.ShardWithMeta.Shard == nil || !client.IsErrObjectNotFound(it.OutError) {
return GetRes{}, it.OutError
}
it.tryGetFromBlobstore(ctx)
if it.Object == nil {
return GetRes{}, it.OutError
}
if it.ShardWithMeta.Shard != nil && it.MetaError != nil {
e.log.Warn(logs.ShardMetaInfoPresentButObjectNotFound,
zap.Stringer("shard_id", it.ShardWithMeta.ID()),
zap.String("error", it.MetaError.Error()),
zap.Stringer("address", prm.addr))
}
}
return GetRes{
obj: it.Object,
}, nil
}
type getShardIterator struct {
Object *objectSDK.Object
SplitInfo *objectSDK.SplitInfo
OutError error
ShardWithMeta hashedShard
MetaError error
HasDegraded bool
ObjectExpired bool
ShardPrm shard.GetPrm
Address oid.Address
Engine *StorageEngine
splitInfoErr *objectSDK.SplitInfoError
}
func (i *getShardIterator) tryGetWithMeta(ctx context.Context) {
i.Engine.iterateOverSortedShards(i.Address, func(_ int, sh hashedShard) (stop bool) {
noMeta := sh.GetMode().NoMetabase()
i.ShardPrm.SetIgnoreMeta(noMeta)
i.HasDegraded = i.HasDegraded || noMeta
res, err := sh.Get(ctx, i.ShardPrm)
if err == nil {
i.Object = res.Object()
return true
}
if res.HasMeta() {
i.ShardWithMeta = sh
i.MetaError = err
}
switch {
case client.IsErrObjectNotFound(err):
return false // ignore, go to next shard
case errors.As(err, &i.splitInfoErr):
if i.SplitInfo == nil {
i.SplitInfo = objectSDK.NewSplitInfo()
}
util.MergeSplitInfo(i.splitInfoErr.SplitInfo(), i.SplitInfo)
_, withLink := i.SplitInfo.Link()
_, withLast := i.SplitInfo.LastPart()
// stop iterating over shards if SplitInfo structure is complete
return withLink && withLast
case client.IsErrObjectAlreadyRemoved(err):
i.OutError = err
return true // stop, return it back
case shard.IsErrObjectExpired(err):
// object is found but should not be returned
i.ObjectExpired = true
return true
default:
i.Engine.reportShardError(sh, "could not get object from shard", err)
return false
}
})
}
func (i *getShardIterator) tryGetFromBlobstore(ctx context.Context) {
// If the object is not found but is present in metabase,
// try to fetch it from blobstor directly. If it is found in any
// blobstor, increase the error counter for the shard which contains the meta.
i.ShardPrm.SetIgnoreMeta(true)
i.Engine.iterateOverSortedShards(i.Address, func(_ int, sh hashedShard) (stop bool) {
if sh.GetMode().NoMetabase() {
// Already visited.
return false
}
res, err := sh.Get(ctx, i.ShardPrm)
i.Object = res.Object()
return err == nil
})
}
// Get reads object from local storage by provided address.
func Get(ctx context.Context, storage *StorageEngine, addr oid.Address) (*objectSDK.Object, error) {
var getPrm GetPrm
getPrm.WithAddress(addr)
res, err := storage.Get(ctx, getPrm)
if err != nil {
return nil, err
}
return res.Object(), nil
}