update more code to use the retry lib.

Signed-off-by: John Mulligan <jmulligan@redhat.com>
Signed-off-by: Sven Anderson <sven@redhat.com>

rbd/rbd_mimic.go

@@ -15,29 +15,34 @@ import (
 	"bytes"
 	"unsafe"
 
+	"github.com/ceph/go-ceph/internal/retry"
 	"github.com/ceph/go-ceph/rados"
 )
 
 // GetImageNames returns the list of current RBD images.
 func GetImageNames(ioctx *rados.IOContext) (names []string, err error) {
-	buf := make([]byte, 4096)
-	for {
-		size := C.size_t(len(buf))
+	var (
+		buf   []byte
+		csize C.size_t
+	)
+	// from 4KiB to 32KiB
+	retry.WithSizes(4096, 1<<15, func(size int) retry.Hint {
+		csize = C.size_t(size)
+		buf = make([]byte, csize)
 		ret := C.rbd_list(cephIoctx(ioctx),
-			(*C.char)(unsafe.Pointer(&buf[0])), &size)
-		if ret == -C.ERANGE {
-			buf = make([]byte, size)
-			continue
-		} else if ret < 0 {
-			return nil, RBDError(ret)
-		}
-		tmp := bytes.Split(buf[:size-1], []byte{0})
-		for _, s := range tmp {
-			if len(s) > 0 {
-				name := C.GoString((*C.char)(unsafe.Pointer(&s[0])))
-				names = append(names, name)
-			}
-		}
-		return names, nil
+			(*C.char)(unsafe.Pointer(&buf[0])), &csize)
+		err = getErrorIfNegative(ret)
+		return retry.Size(int(csize)).If(err == errRange)
+	})
+	if err != nil {
+		return nil, err
 	}
+	tmp := bytes.Split(buf[:csize-1], []byte{0})
+	for _, s := range tmp {
+		if len(s) > 0 {
+			name := C.GoString((*C.char)(unsafe.Pointer(&s[0])))
+			names = append(names, name)
+		}
+	}
+	return names, nil
 }

rbd/snapshot_nautilus.go

@@ -11,8 +11,9 @@ package rbd
 import "C"
 
 import (
-	"fmt"
 	"unsafe"
+
+	"github.com/ceph/go-ceph/internal/retry"
 )
 
 // GetParentInfo looks for the parent of the image and stores the pool, name
@@ -76,27 +77,28 @@ func (image *Image) ListChildren() (pools []string, images []string, err error)
 		return nil, nil, err
 	}
 
-	size := C.size_t(0)
-	ret := C.rbd_list_children3(image.image, nil, &size)
-	if ret < 0 && ret != -C.ERANGE {
-		return nil, nil, RBDError(ret)
-	} else if ret > 0 {
-		return nil, nil, fmt.Errorf("rbd_list_children3() returned %d, expected 0", ret)
-	} else if ret == 0 && size == 0 {
-		return nil, nil, nil
+	var (
+		csize    C.size_t
+		children []C.rbd_linked_image_spec_t
+	)
+	retry.WithSizes(16, 4096, func(size int) retry.Hint {
+		csize = C.size_t(size)
+		children = make([]C.rbd_linked_image_spec_t, csize)
+		ret := C.rbd_list_children3(
+			image.image,
+			(*C.rbd_linked_image_spec_t)(unsafe.Pointer(&children[0])),
+			&csize)
+		err = getErrorIfNegative(ret)
+		return retry.Size(int(csize)).If(err == errRange)
+	})
+	if err != nil {
+		return nil, nil, err
 	}
+	defer C.rbd_linked_image_spec_list_cleanup((*C.rbd_linked_image_spec_t)(unsafe.Pointer(&children[0])), csize)
 
-	// expected: ret == -ERANGE, size contains number of image names
-	children := make([]C.rbd_linked_image_spec_t, size)
-	ret = C.rbd_list_children3(image.image, (*C.rbd_linked_image_spec_t)(unsafe.Pointer(&children[0])), &size)
-	if ret < 0 {
-		return nil, nil, RBDError(ret)
-	}
-	defer C.rbd_linked_image_spec_list_cleanup((*C.rbd_linked_image_spec_t)(unsafe.Pointer(&children[0])), size)
-
-	pools = make([]string, size)
-	images = make([]string, size)
-	for i, child := range children {
+	pools = make([]string, csize)
+	images = make([]string, csize)
+	for i, child := range children[:csize] {
 		pools[i] = C.GoString(child.pool_name)
 		images[i] = C.GoString(child.image_name)
 	}

rbd/watchers_mimic.go

@@ -9,6 +9,10 @@ package rbd
 // #include <rbd/librbd.h>
 import "C"
 
+import (
+	"github.com/ceph/go-ceph/internal/retry"
+)
+
 // ImageWatcher is a representation of the rbd_image_watcher_t from librbd.h
 type ImageWatcher struct {
 	Addr   string
@@ -30,28 +34,28 @@ func (image *Image) ListWatchers() ([]ImageWatcher, error) {
 		return nil, err
 	}
 
-	count := C.ulong(0)
-	ret := C.rbd_watchers_list(image.image, nil, &count)
-	if ret != 0 && ret != -C.ERANGE {
-		return nil, getError(ret)
-	}
-	if ret == 0 && count == 0 {
-		return nil, nil
-	}
-
-	watchers := make([]C.rbd_image_watcher_t, count)
-	ret = C.rbd_watchers_list(image.image, &watchers[0], &count)
-	if ret != 0 && ret != -C.ERANGE {
-		return nil, getError(ret)
+	var (
+		err      error
+		count    C.size_t
+		watchers []C.rbd_image_watcher_t
+	)
+	retry.WithSizes(16, 4096, func(size int) retry.Hint {
+		count = C.size_t(size)
+		watchers = make([]C.rbd_image_watcher_t, count)
+		ret := C.rbd_watchers_list(image.image, &watchers[0], &count)
+		err = getErrorIfNegative(ret)
+		return retry.Size(int(count)).If(err == errRange)
+	})
+	if err != nil {
+		return nil, err
 	}
 	defer C.rbd_watchers_list_cleanup(&watchers[0], count)
 
-	imageWatchers := make([]ImageWatcher, len(watchers))
-	for i, watcher := range watchers {
+	imageWatchers := make([]ImageWatcher, count)
+	for i, watcher := range watchers[:count] {
 		imageWatchers[i].Addr = C.GoString(watcher.addr)
 		imageWatchers[i].Id = int64(watcher.id)
 		imageWatchers[i].Cookie = uint64(watcher.cookie)
 	}
-
 	return imageWatchers, nil
 }