sync() takes minutes while erasing

[Jörn Engel]

On Wed, 20 June 2007 18:26:36 +0200, Joakim Tjernlund wrote:
> On Wed, 2007-06-20 at 11:09 -0500, Josh Boyer wrote:
> > 
> > jffs2_write_super is called during unmount.  If there are blocks pending
> > on the erase list, it's better to erase those now before the unmount is
> > completed.  Saves some time on the next mount.
> 
> No, not if the reboot/unmont is suspended for minutes just because jffs2
> wants to finish erasing. It doesn't save you much, if anything, at
> remount either.
> 
> The erasing in context is just something that needs to be done at some
> point but it don't have to happen now.

In case you need an example:

$ flash_eraseall /dev/mtd0
$ time mount mtd0 /mnt -t jffs2
$ time umount /mnt

Depending on device size, this will take some seconds for mount and some
minutes for umount.  Spending minutes to save some seconds on next mount
hardly sounds sensible.

Jörn

-- 
"Security vulnerabilities are here to stay."
-- Scott Culp, Manager of the Microsoft Security Response Center, 2001