Files
scoutfs/kmod
Zach Brown 888b1394a6 Retry client commit and get log trees separately
The client transaction commit worker has a series of functions that it
calls to commit the current transaction and open the next one.  If any
of them fail, it retries all of them from the beginning each time until
they all succeed.

This pattern behaves badly since we added the strict get_trans_seq and
commit_trans_seq latching in the log_trees.  The server will only commit
the items for a get or commit request once, and will fail a commit
request if it isn't given the seq that matches the current item.

If the server gets an error it can have persisted items while sending an
error to the client.  If this error was for a get request, then the
client will retry all of its transaction write functions.  This includes
the commit request which is now using a stale seq and will fail
indefinitely.  This is visible in the server log as:

  error -5 committing client logs for rid e57e37132c919c4f: invalid log trees item get_trans_seq

The solution is to retry the commit and get phases independently.  This
way a failed get will be retried on its own without running through the
commit phase that had succeeded.  The client will eventually get the
next seq that it can then safely commit.

Signed-off-by: Zach Brown <zab@versity.com>
2025-04-29 11:46:38 -07:00
..