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Merge pull request #1410 from armhold/deadlock2

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unify behavior for max http connections across backends
This commit is contained in:
Alexander Neumann 2017-11-24 21:32:56 +01:00
commit f79698dcdd
6 changed files with 113 additions and 59 deletions
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19
internal/backend/azure/azure.go
View file

@ -227,13 +227,17 @@ func (be *Backend) Load(ctx context.Context, h restic.Handle, length int, offset
}
// Stat returns information about a blob.
func (be *Backend) Stat(ctx context.Context, h restic.Handle) (bi restic.FileInfo, err error) {
func (be *Backend) Stat(ctx context.Context, h restic.Handle) (restic.FileInfo, error) {
debug.Log("%v", h)
objName := be.Filename(h)
blob := be.container.GetBlobReference(objName)
if err := blob.GetProperties(nil); err != nil {
be.sem.GetToken()
err := blob.GetProperties(nil)
be.sem.ReleaseToken()
if err != nil {
debug.Log("blob.GetProperties err %v", err)
return restic.FileInfo{}, errors.Wrap(err, "blob.GetProperties")
}
@ -244,7 +248,11 @@ func (be *Backend) Stat(ctx context.Context, h restic.Handle) (bi restic.FileInf
// Test returns true if a blob of the given type and name exists in the backend.
func (be *Backend) Test(ctx context.Context, h restic.Handle) (bool, error) {
objName := be.Filename(h)
be.sem.GetToken()
found, err := be.container.GetBlobReference(objName).Exists()
be.sem.ReleaseToken()
if err != nil {
return false, err
}
@ -254,7 +262,11 @@ func (be *Backend) Test(ctx context.Context, h restic.Handle) (bool, error) {
// Remove removes the blob with the given name and type.
func (be *Backend) Remove(ctx context.Context, h restic.Handle) error {
objName := be.Filename(h)
be.sem.GetToken()
_, err := be.container.GetBlobReference(objName).DeleteIfExists(nil)
be.sem.ReleaseToken()
debug.Log("Remove(%v) at %v -> err %v", h, objName, err)
return errors.Wrap(err, "client.RemoveObject")
}
@ -282,7 +294,10 @@ func (be *Backend) List(ctx context.Context, t restic.FileType) <-chan string {
defer close(ch)
for {
be.sem.GetToken()
obj, err := be.container.ListBlobs(params)
be.sem.ReleaseToken()
if err != nil {
return
}

43
internal/backend/b2/b2.go
View file

@ -137,31 +137,6 @@ func (be *b2Backend) Location() string {
return be.cfg.Bucket
}
// wrapReader wraps an io.ReadCloser to run an additional function on Close.
type wrapReader struct {
io.ReadCloser
eofSeen bool
f func()
}
func (wr *wrapReader) Read(p []byte) (int, error) {
if wr.eofSeen {
return 0, io.EOF
}
n, err := wr.ReadCloser.Read(p)
if err == io.EOF {
wr.eofSeen = true
}
return n, err
}
func (wr *wrapReader) Close() error {
err := wr.ReadCloser.Close()
wr.f()
return err
}
// IsNotExist returns true if the error is caused by a non-existing file.
func (be *b2Backend) IsNotExist(err error) bool {
return b2.IsNotExist(errors.Cause(err))
@ -192,14 +167,7 @@ func (be *b2Backend) Load(ctx context.Context, h restic.Handle, length int, offs
if offset == 0 && length == 0 {
rd := obj.NewReader(ctx)
wrapper := &wrapReader{
ReadCloser: rd,
f: func() {
cancel()
be.sem.ReleaseToken()
},
}
return wrapper, nil
return be.sem.ReleaseTokenOnClose(rd, cancel), nil
}
// pass a negative length to NewRangeReader so that the remainder of the
@ -209,14 +177,7 @@ func (be *b2Backend) Load(ctx context.Context, h restic.Handle, length int, offs
}
rd := obj.NewRangeReader(ctx, offset, int64(length))
wrapper := &wrapReader{
ReadCloser: rd,
f: func() {
cancel()
be.sem.ReleaseToken()
},
}
return wrapper, nil
return be.sem.ReleaseTokenOnClose(rd, cancel), nil
}
// Save stores data in the backend at the handle.

18
internal/backend/gs/gs.go
View file

@ -204,14 +204,15 @@ func (be *Backend) Save(ctx context.Context, h restic.Handle, rd io.Reader) (err
debug.Log("Save %v at %v", h, objName)
be.sem.GetToken()
// Check key does not already exist
if _, err := be.service.Objects.Get(be.bucketName, objName).Do(); err == nil {
debug.Log("%v already exists", h)
be.sem.ReleaseToken()
return errors.New("key already exists")
}
be.sem.GetToken()
debug.Log("InsertObject(%v, %v)", be.bucketName, objName)
// Set chunk size to zero to disable resumable uploads.
@ -323,7 +324,10 @@ func (be *Backend) Stat(ctx context.Context, h restic.Handle) (bi restic.FileInf
objName := be.Filename(h)
be.sem.GetToken()
obj, err := be.service.Objects.Get(be.bucketName, objName).Do()
be.sem.ReleaseToken()
if err != nil {
debug.Log("GetObject() err %v", err)
return restic.FileInfo{}, errors.Wrap(err, "service.Objects.Get")
@ -336,7 +340,11 @@ func (be *Backend) Stat(ctx context.Context, h restic.Handle) (bi restic.FileInf
func (be *Backend) Test(ctx context.Context, h restic.Handle) (bool, error) {
found := false
objName := be.Filename(h)
be.sem.GetToken()
_, err := be.service.Objects.Get(be.bucketName, objName).Do()
be.sem.ReleaseToken()
if err == nil {
found = true
}
@ -348,7 +356,10 @@ func (be *Backend) Test(ctx context.Context, h restic.Handle) (bool, error) {
func (be *Backend) Remove(ctx context.Context, h restic.Handle) error {
objName := be.Filename(h)
be.sem.GetToken()
err := be.service.Objects.Delete(be.bucketName, objName).Do()
be.sem.ReleaseToken()
if er, ok := err.(*googleapi.Error); ok {
if er.Code == 404 {
err = nil
@ -378,7 +389,10 @@ func (be *Backend) List(ctx context.Context, t restic.FileType) <-chan string {
listReq := be.service.Objects.List(be.bucketName).Prefix(prefix).MaxResults(int64(be.listMaxItems))
for {
be.sem.GetToken()
obj, err := listReq.Do()
be.sem.ReleaseToken()
if err != nil {
fmt.Fprintf(os.Stderr, "error listing %v: %v\n", prefix, err)
return

19
internal/backend/s3/s3.go
View file

@ -263,6 +263,9 @@ func (be *Backend) Save(ctx context.Context, h restic.Handle, rd io.Reader) (err
objName := be.Filename(h)
be.sem.GetToken()
defer be.sem.ReleaseToken()
// Check key does not already exist
_, err = be.client.StatObject(be.cfg.Bucket, objName)
if err == nil {
@ -282,10 +285,8 @@ func (be *Backend) Save(ctx context.Context, h restic.Handle, rd io.Reader) (err
debug.Log("reader is %#T, no specific workaround enabled", rd)
}
be.sem.GetToken()
debug.Log("PutObject(%v, %v)", be.cfg.Bucket, objName)
n, err := be.client.PutObject(be.cfg.Bucket, objName, rd, "application/octet-stream")
be.sem.ReleaseToken()
debug.Log("%v -> %v bytes, err %#v: %v", objName, n, err, err)
@ -358,15 +359,18 @@ func (be *Backend) Stat(ctx context.Context, h restic.Handle) (bi restic.FileInf
objName := be.Filename(h)
var obj *minio.Object
be.sem.GetToken()
obj, err = be.client.GetObject(be.cfg.Bucket, objName)
if err != nil {
debug.Log("GetObject() err %v", err)
be.sem.ReleaseToken()
return restic.FileInfo{}, errors.Wrap(err, "client.GetObject")
}
// make sure that the object is closed properly.
defer func() {
e := obj.Close()
be.sem.ReleaseToken()
if err == nil {
err = errors.Wrap(e, "Close")
}
@ -385,7 +389,11 @@ func (be *Backend) Stat(ctx context.Context, h restic.Handle) (bi restic.FileInf
func (be *Backend) Test(ctx context.Context, h restic.Handle) (bool, error) {
found := false
objName := be.Filename(h)
be.sem.GetToken()
_, err := be.client.StatObject(be.cfg.Bucket, objName)
be.sem.ReleaseToken()
if err == nil {
found = true
}
@ -397,7 +405,11 @@ func (be *Backend) Test(ctx context.Context, h restic.Handle) (bool, error) {
// Remove removes the blob with the given name and type.
func (be *Backend) Remove(ctx context.Context, h restic.Handle) error {
objName := be.Filename(h)
be.sem.GetToken()
err := be.client.RemoveObject(be.cfg.Bucket, objName)
be.sem.ReleaseToken()
debug.Log("Remove(%v) at %v -> err %v", h, objName, err)
if be.IsNotExist(err) {
@ -421,6 +433,9 @@ func (be *Backend) List(ctx context.Context, t restic.FileType) <-chan string {
prefix += "/"
}
// NB: unfortunately we can't protect this with be.sem.GetToken() here.
// Doing so would enable a deadlock situation (gh-1399), as ListObjects()
// starts its own goroutine and returns results via a channel.
listresp := be.client.ListObjects(be.cfg.Bucket, prefix, true, ctx.Done())
go func() {

42
internal/backend/semaphore.go
View file

@ -1,6 +1,10 @@
package backend
import "github.com/restic/restic/internal/errors"
import (
"context"
"github.com/restic/restic/internal/errors"
"io"
)
// Semaphore limits access to a restricted resource.
type Semaphore struct {
@ -26,3 +30,39 @@ func (s *Semaphore) GetToken() {
func (s *Semaphore) ReleaseToken() {
<-s.ch
}
// ReleaseTokenOnClose wraps an io.ReadCloser to return a token on Close. Before returning the token,
// cancel, if provided, will be run to free up context resources.
func (s *Semaphore) ReleaseTokenOnClose(rc io.ReadCloser, cancel context.CancelFunc) io.ReadCloser {
return &wrapReader{rc, false, func() {
if cancel != nil {
cancel()
}
s.ReleaseToken()
}}
}
// wrapReader wraps an io.ReadCloser to run an additional function on Close.
type wrapReader struct {
io.ReadCloser
eofSeen bool
f func()
}
func (wr *wrapReader) Read(p []byte) (int, error) {
if wr.eofSeen {
return 0, io.EOF
}
n, err := wr.ReadCloser.Read(p)
if err == io.EOF {
wr.eofSeen = true
}
return n, err
}
func (wr *wrapReader) Close() error {
err := wr.ReadCloser.Close()
wr.f()
return err
}

31
internal/backend/swift/swift.go
View file

@ -129,11 +129,6 @@ func (be *beSwift) Load(ctx context.Context, h restic.Handle, length int, offset
objName := be.Filename(h)
be.sem.GetToken()
defer func() {
be.sem.ReleaseToken()
}()
headers := swift.Headers{}
if offset > 0 {
headers["Range"] = fmt.Sprintf("bytes=%d-", offset)
@ -147,13 +142,15 @@ func (be *beSwift) Load(ctx context.Context, h restic.Handle, length int, offset
debug.Log("Load(%v) send range %v", h, headers["Range"])
}
be.sem.GetToken()
obj, _, err := be.conn.ObjectOpen(be.container, objName, false, headers)
if err != nil {
debug.Log(" err %v", err)
be.sem.ReleaseToken()
return nil, errors.Wrap(err, "conn.ObjectOpen")
}
return obj, nil
return be.sem.ReleaseTokenOnClose(obj, nil), nil
}
// Save stores data in the backend at the handle.
@ -166,6 +163,9 @@ func (be *beSwift) Save(ctx context.Context, h restic.Handle, rd io.Reader) (err
debug.Log("Save %v at %v", h, objName)
be.sem.GetToken()
defer be.sem.ReleaseToken()
// Check key does not already exist
switch _, _, err = be.conn.Object(be.container, objName); err {
case nil:
@ -179,11 +179,6 @@ func (be *beSwift) Save(ctx context.Context, h restic.Handle, rd io.Reader) (err
return errors.Wrap(err, "conn.Object")
}
be.sem.GetToken()
defer func() {
be.sem.ReleaseToken()
}()
encoding := "binary/octet-stream"
debug.Log("PutObject(%v, %v, %v)", be.container, objName, encoding)
@ -199,6 +194,9 @@ func (be *beSwift) Stat(ctx context.Context, h restic.Handle) (bi restic.FileInf
objName := be.Filename(h)
be.sem.GetToken()
defer be.sem.ReleaseToken()
obj, _, err := be.conn.Object(be.container, objName)
if err != nil {
debug.Log("Object() err %v", err)
@ -211,6 +209,10 @@ func (be *beSwift) Stat(ctx context.Context, h restic.Handle) (bi restic.FileInf
// Test returns true if a blob of the given type and name exists in the backend.
func (be *beSwift) Test(ctx context.Context, h restic.Handle) (bool, error) {
objName := be.Filename(h)
be.sem.GetToken()
defer be.sem.ReleaseToken()
switch _, _, err := be.conn.Object(be.container, objName); err {
case nil:
return true, nil
@ -226,6 +228,10 @@ func (be *beSwift) Test(ctx context.Context, h restic.Handle) (bool, error) {
// Remove removes the blob with the given name and type.
func (be *beSwift) Remove(ctx context.Context, h restic.Handle) error {
objName := be.Filename(h)
be.sem.GetToken()
defer be.sem.ReleaseToken()
err := be.conn.ObjectDelete(be.container, objName)
debug.Log("Remove(%v) -> err %v", h, err)
return errors.Wrap(err, "conn.ObjectDelete")
@ -245,7 +251,10 @@ func (be *beSwift) List(ctx context.Context, t restic.FileType) <-chan string {
err := be.conn.ObjectsWalk(be.container, &swift.ObjectsOpts{Prefix: prefix},
func(opts *swift.ObjectsOpts) (interface{}, error) {
be.sem.GetToken()
newObjects, err := be.conn.ObjectNames(be.container, opts)
be.sem.ReleaseToken()
if err != nil {
return nil, errors.Wrap(err, "conn.ObjectNames")
}