moby/volume/store/restore.go
Brian Goff 4876a9047e Fix usage of boltdb in volume restore
bolt k/v pairs are only valid for the life of a transaction.
This means the memory that the k/v pair is referencing may be invalid if
it is accessed outside of the transaction.
This can potentially cause a panic.

For reference: https://godoc.org/github.com/boltdb/bolt#hdr-Caveats

To fix this issue, unmarshal the stored data into volume meta before
closing the transaction.

Signed-off-by: Brian Goff <cpuguy83@gmail.com>
2016-12-22 11:56:02 -05:00

83 lines
2.2 KiB
Go

package store
import (
"sync"
"github.com/Sirupsen/logrus"
"github.com/boltdb/bolt"
"github.com/docker/docker/volume"
"github.com/docker/docker/volume/drivers"
)
// restore is called when a new volume store is created.
// It's primary purpose is to ensure that all drivers' refcounts are set based
// on known volumes after a restart.
// This only attempts to track volumes that are actually stored in the on-disk db.
// It does not probe the available drivers to find anything that may have been added
// out of band.
func (s *VolumeStore) restore() {
var ls []volumeMetadata
s.db.View(func(tx *bolt.Tx) error {
ls = listMeta(tx)
return nil
})
chRemove := make(chan *volumeMetadata, len(ls))
var wg sync.WaitGroup
for _, meta := range ls {
wg.Add(1)
// this is potentially a very slow operation, so do it in a goroutine
go func(meta volumeMetadata) {
defer wg.Done()
var v volume.Volume
var err error
if meta.Driver != "" {
v, err = lookupVolume(meta.Driver, meta.Name)
if err != nil && err != errNoSuchVolume {
logrus.WithError(err).WithField("driver", meta.Driver).WithField("volume", meta.Name).Warn("Error restoring volume")
return
}
if v == nil {
// doesn't exist in the driver, remove it from the db
chRemove <- &meta
return
}
} else {
v, err = s.getVolume(meta.Name)
if err != nil {
if err == errNoSuchVolume {
chRemove <- &meta
}
return
}
meta.Driver = v.DriverName()
if err := s.setMeta(v.Name(), meta); err != nil {
logrus.WithError(err).WithField("driver", meta.Driver).WithField("volume", v.Name()).Warn("Error updating volume metadata on restore")
}
}
// increment driver refcount
volumedrivers.CreateDriver(meta.Driver)
// cache the volume
s.globalLock.Lock()
s.options[v.Name()] = meta.Options
s.labels[v.Name()] = meta.Labels
s.names[v.Name()] = v
s.globalLock.Unlock()
}(meta)
}
wg.Wait()
close(chRemove)
s.db.Update(func(tx *bolt.Tx) error {
for meta := range chRemove {
if err := removeMeta(tx, meta.Name); err != nil {
logrus.WithField("volume", meta.Name).Warnf("Error removing stale entry from volume db: %v", err)
}
}
return nil
})
}