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endpoint: serialize dataset hierarchy modification within a receiver job

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refs #136
refs #140
This commit is contained in:
Christian Schwarz 2019-03-20 18:52:40 +01:00
parent 2f2e6e6a00
commit 3e71542c78
1 changed files with 48 additions and 28 deletions
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76
endpoint/endpoint.go
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@ -8,6 +8,7 @@ import (
"github.com/pkg/errors"
"github.com/zrepl/zrepl/replication/logic/pdu"
"github.com/zrepl/zrepl/util/chainlock"
"github.com/zrepl/zrepl/zfs"
)
@ -170,13 +171,19 @@ type FSMap interface { // FIXME unused
type Receiver struct {
rootWithoutClientComponent *zfs.DatasetPath
appendClientIdentity bool
recvParentCreationMtx *chainlock.L
}
func NewReceiver(rootDataset *zfs.DatasetPath, appendClientIdentity bool) *Receiver {
if rootDataset.Length() <= 0 {
panic(fmt.Sprintf("root dataset must not be an empty path: %v", rootDataset))
}
return &Receiver{rootWithoutClientComponent: rootDataset.Copy(), appendClientIdentity: appendClientIdentity}
return &Receiver{
rootWithoutClientComponent: rootDataset.Copy(),
appendClientIdentity: appendClientIdentity,
recvParentCreationMtx: chainlock.New(),
}
}
func TestClientIdentity(rootFS *zfs.DatasetPath, clientIdentity string) error {
@ -323,40 +330,53 @@ func (s *Receiver) Receive(ctx context.Context, req *pdu.ReceiveReq, receive zfs
}
// create placeholder parent filesystems as appropriate
//
// Manipulating the ZFS dataset hierarchy must happen exclusively.
// TODO: Use fine-grained locking to allow separate clients / requests to pass
// through the following section concurrently when operating on disjoint
// ZFS dataset hierarchy subtrees.
var visitErr error
f := zfs.NewDatasetPathForest()
f.Add(lp)
getLogger(ctx).Debug("begin tree-walk")
f.WalkTopDown(func(v zfs.DatasetPathVisit) (visitChildTree bool) {
if v.Path.Equal(lp) {
return false
}
ph, err := zfs.ZFSGetFilesystemPlaceholderState(v.Path)
if err != nil {
visitErr = err
return false
}
getLogger(ctx).
WithField("fs", v.Path.ToString()).
WithField("placeholder_state", fmt.Sprintf("%#v", ph)).
Debug("placeholder state for filesystem")
func() {
getLogger(ctx).Debug("begin aquire recvParentCreationMtx")
defer s.recvParentCreationMtx.Lock().Unlock()
getLogger(ctx).Debug("end aquire recvParentCreationMtx")
defer getLogger(ctx).Debug("release recvParentCreationMtx")
if !ph.FSExists {
l := getLogger(ctx).WithField("placeholder_fs", v.Path)
l.Debug("create placeholder filesystem")
err := zfs.ZFSCreatePlaceholderFilesystem(v.Path)
f := zfs.NewDatasetPathForest()
f.Add(lp)
getLogger(ctx).Debug("begin tree-walk")
f.WalkTopDown(func(v zfs.DatasetPathVisit) (visitChildTree bool) {
if v.Path.Equal(lp) {
return false
}
ph, err := zfs.ZFSGetFilesystemPlaceholderState(v.Path)
getLogger(ctx).
WithField("fs", v.Path.ToString()).
WithField("placeholder_state", fmt.Sprintf("%#v", ph)).
WithField("err", fmt.Sprintf("%s", err)).
WithField("errType", fmt.Sprintf("%T", err)).
Debug("placeholder state for filesystem")
if err != nil {
l.WithError(err).Error("cannot create placeholder filesystem")
visitErr = err
return false
}
return true
}
getLogger(ctx).WithField("filesystem", v.Path.ToString()).Debug("exists")
return true // leave this fs as is
})
getLogger(ctx).WithField("visitErr", visitErr).Debug("complete tree-walk")
if !ph.FSExists {
l := getLogger(ctx).WithField("placeholder_fs", v.Path)
l.Debug("create placeholder filesystem")
err := zfs.ZFSCreatePlaceholderFilesystem(v.Path)
if err != nil {
l.WithError(err).Error("cannot create placeholder filesystem")
visitErr = err
return false
}
return true
}
getLogger(ctx).WithField("filesystem", v.Path.ToString()).Debug("exists")
return true // leave this fs as is
})
}()
getLogger(ctx).WithField("visitErr", visitErr).Debug("complete tree-walk")
if visitErr != nil {
return nil, visitErr
}