On Thu, Nov 08, 2018 at 01:29:38PM +0100, Jan Kara wrote: > We can hold j_state_lock for writing at the beginning of > jbd2_journal_commit_transaction() for a rather long time (reportedly for > 30 ms) due cleaning revoke bits of all revoked buffers under it. The > handling of revoke tables as well as cleaning of t_reserved_list, and > checkpoint lists does not need j_state_lock for anything. It is only > needed to prevent new handles from joining the transaction. Generally > T_LOCKED transaction state prevents new handles from joining the > transaction - except for reserved handles which have to allowed to join > while we wait for other handles to complete. > > To prevent reserved handles from joining the transaction while cleaning > up lists, add new transaction state T_SWITCH and watch for it when > starting reserved handles. With this we can just drop the lock for > operations that don't need it. > > Reported-and-tested-by: Adrian Hunter <adrian.hunter@xxxxxxxxx> > Suggested-by: "Theodore Y. Ts'o" <tytso@xxxxxxx> > Signed-off-by: Jan Kara <jack@xxxxxxx> Applied, thanks. - Ted
