rebase: update go-ceph to v0.7.0

updating go-ceph to latest 0.7.0
release.

Signed-off-by: Madhu Rajanna <madhupr007@gmail.com>

vendor/github.com/ceph/go-ceph/rbd/metadata.go

@@ -0,0 +1,149 @@
+package rbd
+
+// #cgo LDFLAGS: -lrbd
+// #include <stdlib.h>
+// #include <rbd/librbd.h>
+import "C"
+
+import (
+	"unsafe"
+
+	"github.com/ceph/go-ceph/internal/cutil"
+	"github.com/ceph/go-ceph/internal/retry"
+)
+
+// GetMetadata returns the metadata string associated with the given key.
+//
+// Implements:
+//  int rbd_metadata_get(rbd_image_t image, const char *key, char *value, size_t *vallen)
+func (image *Image) GetMetadata(key string) (string, error) {
+	if err := image.validate(imageIsOpen); err != nil {
+		return "", err
+	}
+
+	c_key := C.CString(key)
+	defer C.free(unsafe.Pointer(c_key))
+
+	var (
+		buf []byte
+		err error
+	)
+	retry.WithSizes(4096, 262144, func(size int) retry.Hint {
+		csize := C.size_t(size)
+		buf = make([]byte, csize)
+		// rbd_metadata_get is a bit quirky and *does not* update the size
+		// value if the size passed in >= the needed size.
+		ret := C.rbd_metadata_get(
+			image.image, c_key, (*C.char)(unsafe.Pointer(&buf[0])), &csize)
+		err = getError(ret)
+		return retry.Size(int(csize)).If(err == errRange)
+	})
+	if err != nil {
+		return "", err
+	}
+	return C.GoString((*C.char)(unsafe.Pointer(&buf[0]))), nil
+}
+
+// SetMetadata updates the metadata string associated with the given key.
+//
+// Implements:
+//  int rbd_metadata_set(rbd_image_t image, const char *key, const char *value)
+func (image *Image) SetMetadata(key string, value string) error {
+	if err := image.validate(imageIsOpen); err != nil {
+		return err
+	}
+
+	c_key := C.CString(key)
+	c_value := C.CString(value)
+	defer C.free(unsafe.Pointer(c_key))
+	defer C.free(unsafe.Pointer(c_value))
+
+	ret := C.rbd_metadata_set(image.image, c_key, c_value)
+	if ret < 0 {
+		return rbdError(ret)
+	}
+
+	return nil
+}
+
+// RemoveMetadata clears the metadata associated with the given key.
+//
+// Implements:
+//  int rbd_metadata_remove(rbd_image_t image, const char *key)
+func (image *Image) RemoveMetadata(key string) error {
+	if err := image.validate(imageIsOpen); err != nil {
+		return err
+	}
+
+	c_key := C.CString(key)
+	defer C.free(unsafe.Pointer(c_key))
+
+	ret := C.rbd_metadata_remove(image.image, c_key)
+	if ret < 0 {
+		return rbdError(ret)
+	}
+
+	return nil
+}
+
+// ListMetadata returns a map containing all metadata assigned to the RBD image.
+//
+// Implements:
+//  int rbd_metadata_list(rbd_image_t image, const char *start, uint64_t max,
+//                        char *keys, size_t *key_len, char *values, size_t *vals_len);
+func (image *Image) ListMetadata() (map[string]string, error) {
+	if err := image.validate(imageIsOpen); err != nil {
+		return nil, err
+	}
+
+	var (
+		err      error
+		keysbuf  []byte
+		keysSize C.size_t
+		valsbuf  []byte
+		valsSize C.size_t
+	)
+	retry.WithSizes(4096, 262144, func(size int) retry.Hint {
+		keysbuf = make([]byte, size)
+		keysSize = C.size_t(size)
+		valsbuf = make([]byte, size)
+		valsSize = C.size_t(size)
+		// the rbd_metadata_list function can use a start point and a limit.
+		// we do not use it and prefer our retry helper and just allocating
+		// buffers large enough to take all the keys and values
+		ret := C.rbd_metadata_list(
+			image.image,
+			(*C.char)(unsafe.Pointer(&empty[0])), // always start at the beginning (no paging)
+			0,                                    // fetch all key-value pairs
+			(*C.char)(unsafe.Pointer(&keysbuf[0])),
+			&keysSize,
+			(*C.char)(unsafe.Pointer(&valsbuf[0])),
+			&valsSize)
+
+		err = getError(ret)
+		nextSize := valsSize
+		if keysSize > nextSize {
+			nextSize = keysSize
+		}
+		return retry.Size(int(nextSize)).If(err == errRange)
+	})
+	if err != nil {
+		return nil, err
+	}
+
+	m := map[string]string{}
+	keys := cutil.SplitBuffer(keysbuf[:keysSize])
+	vals := cutil.SplitBuffer(valsbuf[:valsSize])
+	if len(keys) != len(vals) {
+		// this should not happen (famous last words)
+		return nil, errRange
+	}
+	for i := range keys {
+		m[keys[i]] = vals[i]
+	}
+	return m, nil
+}
+
+// rather than allocate memory every time that ListMetadata is called,
+// define a static byte slice to stand in for the C "empty string"
+var empty = []byte{0}