On 6/11/20 11:26 AM, Vladimir Sementsov-Ogievskiy wrote:
The NBD spec was recently updated to clarify that max_block doesn't
relate to NBD_CMD_WRITE_ZEROES with NBD_CMD_FLAG_FAST_ZERO (which
mirrors Qemu flag BDRV_REQ_NO_FALLBACK). To drop the restriction we
need new max_pwrite_zeroes_fast.
The NBD spec was recently updated to clarify that max_block doesn't
relate to NBD_CMD_WRITE_ZEROES with NBD_CMD_FLAG_FAST_ZERO (which
mirrors Qemu flag BDRV_REQ_NO_FALLBACK). To drop the restriction we
need new max_pwrite_zeroes_fast.
Default value of new max_pwrite_zeroes_fast is zero and it