Re: [PATCH] 2.5.x write_super is not for syncing

[Chris Mason <mason@suse.com>]

On Mon, 2002-12-02 at 17:07, Andrew Morton wrote:

> Except for the s_dirt test in here.  If s_dirt is zero and we
> have dirty inodes, the filesystem _still_ is not told what to
> do.

Perhaps dirty inodes imply s_dirt should be true?

> 
> I don't think we'll ever get this right until we start telling the
> filesystem what's happening.  So instead of all these little
> presumptuous micro-syncs which we're doing in there, we need to turn
> this inside out and just call sb->s_op->sync_everything_for_umount()
> and let the fs decide how to get everything tight on disk.
> 
> That's a bit drastic.  At a minimum we need to remove that s_dirt
> test and make the commit_super() call unconditional.
> 
> What would that break?

Not much, since foofs_commit_super could always check for s_dirt if the
local FS really cared.

The downside is that since we don't check for s_dirt in commit_supers(),
the FS might get sunk twice if the we need to restart at the head of the
supers list due to unmount.  But, a double sync is possible anyway under
FS load in the same situation.

-chris