JFFS2 mount time

Gareth Bult (Encryptec) Gareth at Encryptec.net
Wed Dec 15 20:02:54 EST 2004


Sure, the file I've been changing is blkmtd.c.

The device I'm aiming for and testing on is 256Mb with a 128k erase

Currently I'm using the code included in the 2.6.9 kernel source tree
with tools from cvs as of about a week ago.

Is this likely to contain the latest speedups or should I be looking


On Wed, 2004-12-15 at 18:15 -0600, Josh Boyer wrote:
> Gareth Bult (Encryptec) wrote:
> > Hi,
> > 
> > I've been working on the MTD block driver for JFFS2 and now seem to have
> > a relatively stable environment with a JFFS2 root filesystem on a USB
> > flash key device. 
> > (mtd block device speed now approximates actual device speed on both
> > read and write)
> I assume you mean blkmtd here.  The mtdblock driver is used to present 
> an IDE type interface to flash, whereas blkmtd is used to present a 
> flash interface to an IDE type device.
> > 
> > It seems to be much quicker (generally) than the previous ext2
> > incarnation.
> > 
> > However, I'm looking at 30secs to mount the root filesystem.
> How big of a device?
> > a. Is it possible (conceptually) to background the mount scan so the
> > system can boot while the scan happens ?
> Which version of the code are you using?  Mount time has been 
> significantly improved in newer versions of the code.
> > b. Is there an easy way to bypass the scan and does JFFS3 do this ? 
> Not that I know of, because the code needs to read the node information 
> in order to get the versioning of inodes, etc. correct.
> JFFS3 is essentially the exact same code base as JFFS2 right now.  It 
> was just forked about a week ago.
> josh

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