On Jan 06, 2025 / 14:47, Damien Le Moal wrote: > On 12/25/24 7:09 PM, Shin'ichiro Kawasaki wrote: > > The current null_blk implementation checks if any bad blocks exist in > > the target blocks of each IO. If so, the IO fails and data is not > > transferred for all of the IO target blocks. However, when real storage > > devices have bad blocks, the devices may transfer data partially up to > > the first bad blocks. Especially, when the IO is a write operation, such > > partial IO leaves partially written data on the device. > > > > To simulate such partial IO using null_blk, perform the data transfer > > from the IO start block to the block just before the first bad block. > > Introduce __null_handle_rq() to support partial data transfer. Modify > > null_handle_badblocks() to calculate the size of the partial data > > transfer and call __null_handle_rq(). > > We should have an option to control this behavior to be able to mimic actual > devices. E.g. SAS devices may do partial data transfers before hitting a bad > block, but ATA devices will not (it is always all or nothing with ATA). The > current default corresponds to an ATA drive behavior and this change allows > emulating a SAS drive behavior. So let's control this with an option. Thanks. Will do so in v3.
