jffs2: too few erase blocks

Duke ezbonites at gmail.com
Fri Oct 26 17:02:04 EDT 2007

On 10/26/07, Duke <ezbonites at gmail.com> wrote:
> On 10/25/07, Jamie Lokier <jamie at shareable.org> wrote:
> > Josh Boyer wrote:
> > > > Hi All,
> > > > What's the deal with "too few erase blocks" message?
> > > > Is one block too few for a jffs2 partition?
> > > > My block size if 256K and I created a small jffs2 256K partition for
> > > > read/writing.
> > > > Is this really too small for jffs2? If so, is there anything I can do for this?
> > >
> > > Yes, it's too small.  JFFS2 requires a certain percentage of blocks in
> > > the partition to be reserved for it's usage.  At one point, it was 5
> > > eraseblocks.
> >
> > Fwiw, 5 blocks worth of free space is no guarantee that it'll be fine.
> > I have a 1MB JFFS2 partition with 64kB eraseblocks.  That's 320kB in 5
> > blocks.  But it can return disk full errors when reporting more than
> > 320kB free with 'df' (somewhere between 5 and 6 blocks worth), and it
> > can also do strange things shortly before it returns disk full errors,
> > like spending lots of CPU on GC.
> Is there another read/write filesystem I can use in this space?
> If I were to create a subdirectory and rw to that dir only? and can I
> do this with mtd_debug tool?

Just to clarity myself a bit here. There is nothing stopping me from
using the cp or mv (or any other file modification command for that
matter) to update one directory but I would like to be able to verify
the data is actually written and I thought perhaps mtd_debug or some
other mtd tool might be able to verify this. Maybe it's not maybe it
is, I would like to find out.

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