Re: [PATCH] 2.4.x write barriers (updated for ext3)

James Bottomley
2002-03-04T15:04:00Z

phillips@bonn-fries.net said:
> But chances are, almost all the IOs ahead of the journal commit belong
> to your same filesystem anyway, so you may be worrying too much about
> possibly waiting for something on another partition.

My impression is that most modern JFS can work on multiple transactions
simultaneously. All you really care about, I believe, is I/O ordering within
the transaction. However, separate transactions have no I/O ordering
requirements with respect to each other (unless they actually overlap). Using
ordered tags imposes a global ordering, not just a local transaction ordering,
so they may not be the most appropriate way to ensure the ordering of writes
within a single transaction.

I'm not really a JFS expert, so perhaps those who actually develop these
filesystems could comment?

James