Re: [RFC] Draft Linux kernel interfaces for ZBC drives

[Jeff Moyer <jmoyer@redhat.com>]

"Theodore Ts'o" <tytso@mit.edu> writes:

>  * We can also further shrink the structure by removing the
>  * z_checkpoint_offset element, since most of the time
>  * z_write_ptr_offset and z_checkpoint_offset will be the same.  The
>  * only time they will be different is after a write is interrupted
>  * via an unexpected power removal

This may fall into the nit-picking category, but at runtime I'd expect
the write pointer and the checkpoint lba to be different more often than
not, unless you're doing all FUA writes, or are issuing flushes after
every write.

After a power loss event, do we know what READ will return when you try
to read between the checkpoint lba and the write pointer?  I didn't see
that in the linked specification, and I think it's important to know.

Cheers,
Jeff