Re: JFFS2 mount time

David Woodhouse
2004-01-13T13:39:00Z

On Tue, 2004-01-13 at 14:50 +0200, Jarkko Lavinen (NMP/Helsinki) wrote:
> Is there anything that could be done to reduce the mount time of large
> JFFS2 partitions? Lazy mounting with prioritized scanning?

We improved it a lot by not checking CRC32 on all nodes until later --
but we still need to read the whole medium at mount time.

We _can_ fix that. There's a limited amount of knowledge we're gaining
from our scan at mount time. For each inode on the medium, we need:
Its nlink
A list of the physical addresses of all its nodes

We currently read the whole of every eraseblock to work this out.
However, we could write a block 'tailer' at the _end_ of each eraseblock
as we fill it, containing enough information in compressed form about
the contents of the eraseblock.

That would mean that we only have to read a small proportion of each
properly-finished eraseblock, and should speed up the mount
significantly.

--
dwmw2