[illumos-Developer] Replay problems with new zvol_replay_truncate (was iSCSI UNMAP...)

[Dan McDonald]

On Fri, Feb 25, 2011 at 08:57:51AM -0800, George Wilson wrote:

<SNIP!>

>We also need to test the log/replay logic. So I would recommend
>setting a breakpoint after zvol_log_truncate() and forcing a panic.

I did just this, and forced a panic.  (Sidenote:  once the dump finishes, the
machine locks after printing "100%" and I get no actual dump...).

After the panic, I booted in with kmdb -d, and set this breakpoint
immediately:

	::bp zfs`zvol_replay_truncate

figuring the system would break there, since I wrote my unmap to the log with
zvol_log_truncate().

No luck --> machine boots all the way to multiuser and login.  And the blocks
are not reclaimed.  Only a low-level format from the iSCSI initiator does
anything.  :-/

I tried one change prior to sending this note, and that was to assign
itx_private to the zvol state in zvol_log_truncate() like the
zvol_log_write() call does.  Also no luck.

I've updated the webrev:

	http://www.kebe.com/~danmcd/webrevs/unmap/

but I'm sure I'm missing something in zvol_log_truncate().  I just don't know
what precisely.

I'm unavailable the rest of the day today, but I will be at least reading
mail v. late this evening, and maybe even getting some more work done if I
have a flash of insight during my unavailable time, or someone else does.

Thanks again for your time & patience,
Dan