blkdiscardzeroes

return true if discarded blocks are read as zeroes

This call returns true if blocks on device that have been discarded by a call to blkdiscard are returned as blocks of zero bytes when read the next time.

If it returns false, then it may be that discarded blocks are read as stale or random data.

This function depends on the feature "blkdiscardzeroes". See also feature_available.

Parameters:

this	A GuestfsSession object

Returns:

the returned value, or -1 on error