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loopback: always return error if no loopback device 

simplify the error handling for openNextAvailableLoopback and avoid
named return values

Signed-off-by: Giuseppe Scrivano <gscrivan@redhat.com>
This commit is contained in:
Giuseppe Scrivano 2024-08-06 12:12:31 +02:00
parent b8f828d4a2
commit d31e825e20
No known key found for this signature in database
GPG Key ID: 67E38F7A8BA21772
1 changed files with 8 additions and 20 deletions
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28
pkg/loopback/attach_loopback.go
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@ -41,11 +41,10 @@ func getNextFreeLoopbackIndex() (int, error) {
return index, err
}
func openNextAvailableLoopback(sparseName string, sparseFile *os.File) (loopFile *os.File, err error) {
func openNextAvailableLoopback(sparseName string, sparseFile *os.File) (*os.File, error) {
// Read information about the loopback file.
var st syscall.Stat_t
err = syscall.Fstat(int(sparseFile.Fd()), &st)
if err != nil {
if err := syscall.Fstat(int(sparseFile.Fd()), &st); err != nil {
logrus.Errorf("Reading information about loopback file %s: %v", sparseName, err)
return nil, ErrAttachLoopbackDevice
}
@ -70,7 +69,7 @@ func openNextAvailableLoopback(sparseName string, sparseFile *os.File) (loopFile
target := fmt.Sprintf("/dev/loop%d", index)
// OpenFile adds O_CLOEXEC
loopFile, err = os.OpenFile(target, os.O_RDWR, 0o644)
loopFile, err := os.OpenFile(target, os.O_RDWR, 0o644)
if err != nil {
// The kernel returns ENXIO when opening a device that is in the "deleting" or "rundown" state, so
// just treat ENXIO as if the device does not exist.
@ -100,13 +99,12 @@ func openNextAvailableLoopback(sparseName string, sparseFile *os.File) (loopFile
loopFile.Close()
// If the error is EBUSY, then try the next loopback
if err != syscall.EBUSY {
logrus.Errorf("Cannot set up loopback device %s: %s", target, err)
return nil, ErrAttachLoopbackDevice
if err == syscall.EBUSY {
continue
}
// Otherwise, we keep going with the loop
continue
logrus.Errorf("Cannot set up loopback device %s: %s", target, err)
return nil, ErrAttachLoopbackDevice
}
// Check if the loopback driver and underlying filesystem agree on the loopback file's
@ -119,18 +117,8 @@ func openNextAvailableLoopback(sparseName string, sparseFile *os.File) (loopFile
if dev != uint64(st.Dev) || ino != st.Ino {
logrus.Errorf("Loopback device and filesystem disagree on device/inode for %q: %#x(%d):%#x(%d) vs %#x(%d):%#x(%d)", sparseName, dev, dev, ino, ino, st.Dev, st.Dev, st.Ino, st.Ino)
}
// In case of success, we finished. Break the loop.
break
return loopFile, nil
}
// This can't happen, but let's be sure
if loopFile == nil {
logrus.Errorf("Unreachable code reached! Error attaching %s to a loopback device.", sparseFile.Name())
return nil, ErrAttachLoopbackDevice
}
return loopFile, nil
}
// AttachLoopDevice attaches the given sparse file to the next