This flag means "wait for all pending requests before returning to userland".
There are pending events for sure, because we just created new provider and
other classes want to taste it, but we cannot answer on I/O requests until
we're here.
4 mutex operations per I/O requests.
- Use only one mutex to protect both (incoming and outgoing) queue.
As MUTEX_PROFILING(9) shows, there is no big contention for this lock.
- Protect sc_queue_count with queue mutex, instead of doing atomic
operations on it.
- Remove DROP_GIANT()/PICKUP_GIANT() - ggate is marked as MPSAFE and no
Giant there.
in BSD class, ie. if provider below us uses the same metadata, don't
create slices based on the metadata.
This allows to create slices on geoms with rank != 1 without hacks.
Discussed with: phk
Approved by: phk
MFC after: 2 weeks
the given providers. Without even one of the configured components there
should be no way to get the secret.
Supported by: WHEEL Sp. z o.o.
http://www.wheel.pl
(we ignore it).
- Remove code used for handling spoil events, as spoiling is not possible
anymore, because we keep consumers open for writing all the time.
MFC after: 4 days
After this change, when component is disconnected because of an I/O error,
it will not be connected and synchronized automatically, it will be logged
as broken and skipped. Autosynchronization can occur, when component is
disconnected (on orphan event) and connected again - there were no I/O
error, so there is no need to not connected the component, but when there were
writes while it wasn't connected, it will be synchronized.
This fix cases, when component is disconnected because of I/O error and can be
connected again and again.
- Bump version number.
- Implement backward compatibility mechanism. After this change when metadata in
old version is detected, it is automatically upgraded to the new (current)
version.
After this change, when component is disconnected because of an I/O error,
it will not be connected and synchronized automatically, it will be logged
as broken and skipped. Autosynchronization can occur, when component is
disconnected (on orphan event) and connected again - there were no I/O
error, so there is no need to not connected the component, but when there were
writes while it wasn't connected, it will be synchronized.
This fix cases, when component is disconnected because of I/O error and can be
connected again and again.
- Bump version number.
- Add version change history.
- Implement backward compatibility mechanism. After this change when metadata in
old version is detected, it is automatically upgraded to the new (current)
version.
while doing g_(read|write)_data() (e.g. BSD). This can cause a deadlock
in MIRROR class. Not sure if this is safe to drop the topology lock in BSD
class, so change the code in MIRROR class to avoid this deadlock.
Keeping consumers open when device is closed is very hard. We need to
open consumers sometimes to update metadata, etc.
Many hacks was introduced in the past to made it possible. You cannot
be sure that you can open consumer for writing always, even if you think
it should be allowed. If one of the mirror components is for example da0
and you try to open it, you can get EPERM when da0s1 is opened for reading
(because BSD class opens consumers (da0) with an extra 'e' bit set).
Waiting for the events queue to be empty may do the trick, but it makes
code much uglier (as you cannot always call g_waitidle()), it doesn't
solve all edge cases and it can introduce deadlocks if there are events
in the queue that wait for gmirror.
I removed those hacks. Now all consumers are open r1w1e1 always, even if
device is closed. Maybe it is less clean from GEOM perspective, but simpify
code a lot and make it much more reliable.
The only issue was retaste event which is sent when we close consumers
opened for writing. I ignore retaste event by not detaching consumer
immediately (so retaste event is not send to my class) and sending event
right after it to detach and destroy consumer.
