/// <summary>
/// Creates a volume root handle or retrieves an existing one.
/// </summary>
/// <remarks>
/// This is the un-synchronized get-or-add operation resulting in <see cref="VolumeAccessor"/>
/// not being thread-safe.
/// The returned handle should not be disposed.
/// </remarks>
private SafeFileHandle TryGetVolumeHandle(ulong volumeSerial)
{
SafeFileHandle volumeHandle;
if (!m_volumeHandles.TryGetValue(volumeSerial, out volumeHandle))
{
VolumeGuidPath volumeRootPath = m_map.TryGetVolumePathBySerial(volumeSerial);
if (!volumeRootPath.IsValid)
{
return(null);
}
OpenFileResult openResult = FileUtilities.TryCreateOrOpenFile(
volumeRootPath.GetDevicePath(),
FileDesiredAccess.GenericRead,
FileShare.ReadWrite | FileShare.Delete,
FileMode.Open,
FileFlagsAndAttributes.None,
out volumeHandle);
if (!openResult.Succeeded)
{
Contract.Assert(volumeHandle == null);
return(null);
}
m_volumeHandles.Add(volumeSerial, volumeHandle);
}
return(volumeHandle);
}
/// <summary>
/// Creates a volume root handle or retrieves an existing one.
/// </summary>
/// <remarks>
/// This is the un-synchronized get-or-add operation resulting in <see cref="FileAccessor"/>
/// not being thread-safe.
/// </remarks>
private SafeFileHandle TryGetVolumeRoot(ulong volumeSerial)
{
SafeFileHandle volumeRootHandle;
if (!m_volumeRootHandles.TryGetValue(volumeSerial, out volumeRootHandle))
{
VolumeGuidPath volumeRootPath = m_map.TryGetVolumePathBySerial(volumeSerial);
if (!volumeRootPath.IsValid)
{
return(null);
}
if (
!FileUtilities.TryOpenDirectory(
volumeRootPath.Path,
FileShare.ReadWrite | FileShare.Delete,
out volumeRootHandle).Succeeded)
{
Contract.Assert(volumeRootHandle == null);
return(null);
}
m_volumeRootHandles.Add(volumeSerial, volumeRootHandle);
}
return(volumeRootHandle);
}