frostfs-node/pkg/local_object_storage/shard/mode.go

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package shard
import (
"errors"
"github.com/nspcc-dev/neofs-node/pkg/local_object_storage/shard/mode"
)
// ErrReadOnlyMode is returned when it is impossible to apply operation
// that changes shard's memory due to the "read-only" shard's mode.
var ErrReadOnlyMode = errors.New("shard is in read-only mode")
// ErrDegradedMode is returned when operation requiring metabase is executed in degraded mode.
var ErrDegradedMode = errors.New("shard is in degraded mode")
// SetMode sets mode of the shard.
//
// Returns any error encountered that did not allow
// setting shard mode.
func (s *Shard) SetMode(m mode.Mode) error {
s.m.Lock()
defer s.m.Unlock()
return s.setMode(m)
}
func (s *Shard) setMode(m mode.Mode) error {
components := []interface{ SetMode(mode.Mode) error }{
s.metaBase, s.blobStor,
}
if s.hasWriteCache() {
components = append(components, s.writeCache)
}
if s.pilorama != nil {
components = append(components, s.pilorama)
}
// The usual flow of the requests (pilorama is independent):
// writecache -> blobstor -> metabase
// For mode.ReadOnly and mode.Degraded the order is:
// writecache -> blobstor -> metabase
// For mode.ReadWrite it is the opposite:
// metabase -> blobstor -> writecache
if m != mode.ReadWrite {
if s.hasWriteCache() {
components[0], components[2] = components[2], components[0]
} else {
components[0], components[1] = components[1], components[0]
}
}
for i := range components {
if err := components[i].SetMode(m); err != nil {
return err
}
}
s.info.Mode = m
return nil
}
// GetMode returns mode of the shard.
func (s *Shard) GetMode() mode.Mode {
s.m.RLock()
defer s.m.RUnlock()
return s.info.Mode
}