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projectquota: protect concurrent map access

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Protect access to q.quotas map, and lock around changing nextProjectID.

Techinically, the lock in findNextProjectID() is not needed as it is
only called during initialization, but one can never be too careful.

Fixes: 52897d1c09 ("projectquota: utility class for project quota controls")
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
This commit is contained in:
Kir Kolyshkin 2019-07-31 11:02:42 -07:00
parent 589f1dad8d
commit 1ac0a66a64
2 changed files with 12 additions and 3 deletions
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12
daemon/graphdriver/quota/projectquota.go
View file

@ -153,9 +153,11 @@ func NewControl(basePath string) (*Control, error) {
// SetQuota - assign a unique project id to directory and set the quota limits
// for that project id
func (q *Control) SetQuota(targetPath string, quota Quota) error {
q.RLock()
projectID, ok := q.quotas[targetPath]
q.RUnlock()
if !ok {
q.Lock()
projectID = q.nextProjectID
//
@ -163,11 +165,12 @@ func (q *Control) SetQuota(targetPath string, quota Quota) error {
//
err := setProjectID(targetPath, projectID)
if err != nil {
q.Unlock()
return err
}
q.quotas[targetPath] = projectID
q.nextProjectID++
q.Unlock()
}
//
@ -204,8 +207,9 @@ func setProjectQuota(backingFsBlockDev string, projectID uint32, quota Quota) er
// GetQuota - get the quota limits of a directory that was configured with SetQuota
func (q *Control) GetQuota(targetPath string, quota *Quota) error {
q.RLock()
projectID, ok := q.quotas[targetPath]
q.RUnlock()
if !ok {
return errors.Errorf("quota not found for path: %s", targetPath)
}
@ -276,6 +280,8 @@ func setProjectID(targetPath string, projectID uint32) error {
// findNextProjectID - find the next project id to be used for containers
// by scanning driver home directory to find used project ids
func (q *Control) findNextProjectID(home string) error {
q.Lock()
defer q.Unlock()
files, err := ioutil.ReadDir(home)
if err != nil {
return errors.Errorf("read directory failed: %s", home)

3
daemon/graphdriver/quota/types.go
View file

@ -2,6 +2,8 @@
package quota // import "github.com/docker/docker/daemon/graphdriver/quota"
import "sync"
// Quota limit params - currently we only control blocks hard limit
type Quota struct {
Size uint64
@ -11,6 +13,7 @@ type Quota struct {
// who wants to apply project quotas to container dirs
type Control struct {
backingFsBlockDev string
sync.RWMutex // protect nextProjectID and quotas map
nextProjectID uint32
quotas map[string]uint32
}