internal static bool IsStorageSupportingO_Direct(Logger log, string path)
{
var filename = Path.Combine(path, "test-" + Guid.NewGuid() + ".tmp");
var fd = Syscall.open(filename,
OpenFlags.O_WRONLY | PerPlatformValues.OpenFlags.O_DSYNC | PerPlatformValues.OpenFlags.O_DIRECT |
PerPlatformValues.OpenFlags.O_CREAT, FilePermissions.S_IWUSR | FilePermissions.S_IRUSR);
int result;
try
{
if (fd == -1)
{
if (log.IsInfoEnabled)
{
log.Info(
$"Failed to create test file at \'{filename}\'. Cannot determine if O_DIRECT supported by the file system. Assuming it is");
}
return(true);
}
bool usingWrite;
result = Syscall.AllocateFileSpace(fd, 64L * 1024, filename, out usingWrite);
if (usingWrite)
{
if (log.IsInfoEnabled)
{
log.Info(
$"Failed to allocate test file at \'{filename}\'. (rc = {result}) but had success with pwrite. New file allocations will take longer time with pwrite");
}
}
if (result == (int)Errno.EINVAL)
{
if (log.IsInfoEnabled)
{
log.Info(
$"Cannot allocate (rc = EINVAL) to a file \'{filename}\' opened using O_DIRECT. Assuming O_DIRECT is not supported by this file system");
}
return(false);
}
if (result != 0)
{
if (log.IsInfoEnabled)
{
log.Info(
$"Failed to allocate test file at \'{filename}\'. (rc = {result}). Cannot determine if O_DIRECT supported by the file system. Assuming it is");
}
}
}
finally
{
result = Syscall.close(fd);
if (result != 0)
{
if (log.IsInfoEnabled)
{
log.Info($"Failed to close test file at \'{filename}\'. (rc = {result}).");
}
}
result = Syscall.unlink(filename);
if (result != 0)
{
if (log.IsInfoEnabled)
{
log.Info($"Failed to delete test file at \'{filename}\'. (rc = {result}).");
}
}
}
return(true);
}