Messages in this thread | | | From | Daniel Phillips <> | Subject | Re: [patch] sys_sync livelock fix | Date | Thu, 14 Feb 2002 01:49:03 +0100 |
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On February 14, 2002 01:37 am, Andrew Morton wrote: > Daniel Phillips wrote: > > > > On February 13, 2002 11:24 pm, Bill Davidsen wrote: > > > ... > > > It doesn't matter, if you write the existing dirty buffers the filesystem > > > type is irrelevant. > > > > Incorrect. The modern crop of filesystems has the concept of consistency > > points, and data written after a consistency point is irrelevant except to the > > next consistency point. IOW, it's often ok to leave some buffers dirty on a > > sync. But for a dumb filesystem you just have to guess at what's needed for > > a consistency point, and the best guess is 'whatever's dirty at the time of > > sync'. > > > > For metadata-only journalling the issues get more subtle and we need a ruling > > from the ext3 guys. > > The current implementation of fsync_dev is about as good as > it'll get for journal=writeback mode - write the data, > run a commit, write the data again then wait on it all.
What's the theory behind writing the data both before and after the commit?
> > > > Sorry, I don't see the connection to sync. > > I don't understand the whole thread :)
Dangerous advocacy of the broken SuS semantics for sync, has to be stamped out before it spreads ;-)
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