Zach BrownandZach Brown ff532eba75 scoutfs: recover max lock write_version ...

Write locks are given an increasing version number as they're granted
which makes its way into items in the log btrees and is used to find the
most recent version of an item.

The initialization of the lock server's next write_version for granted
locks dates back to the initial prototype of the forest of log btrees.
It is only initialized to zero as the module is loaded.  This means that
reloading the module, perhaps by rebooting, resets all the item versions
to 0 and can lead to newly written items being ignored in favour of
older existing items with greater versions from a previous mount.

To fix this we initialize the lock server's write_version to the
greatest of all the versions in items in log btrees.  We add a field to
the log_trees struct which records the greatest version which is
maintained as we write out items in transactions.  These are read by the
server as it starts.

Then lock recovery needs to include the write_version so that the
lock_server can be sure to set the next write_version past the greatest
version in the currently granted locks.

Signed-off-by: Zach Brown <zab@versity.com>

2020-10-30 11:14:10 -07:00

kmod

scoutfs: recover max lock write_version

2020-10-30 11:14:10 -07:00

S

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