Roman, > In the ATA layer there is the sysfs file "discard_zeroes_data", which > tells whether or not to expect zeroes after a discard. That flag does > not appear to be always correct, e.g. I have some SSDs which do > observably read back zeroes after a discard, but the flag still says > "0". It is hardwired to "0" for backwards compatibility. We don't support discards for clearing block ranges anymore. There is an explicit zeroing operation for that use case. -- Martin K. Petersen Oracle Linux Engineering
