jffs2_scan_make_ino_cache() in scan.c very slow, new improvment

[Joakim Tjernlund]

Hi again

I done some more digging and as far as I can tell it's not possible to omit the
CRC check. Questions:
Is it possible to change the writeout of inode's in such away that the
CRC check can be omitted?
Idea: write the whole node, but replace the data_crc with 0xffffffff, then
write the real data_crc. At scan time you only need to check if the data_crc is 0xfffffff
or not. This wont work if 0xffffffff is a legal CRC value, does someone know?
One could also use the flags field in same way?

Comments? 

Adler32:
I ran a quick test where I swapped crc32 to adler32 in jffs2_scan_inode_node () and
that lowered my mount time with 21 % (from 848 jiffies to 666 jiffies). How 
about swapping crc32 to adler32? This could be a compile time option or stored somewhere
in the FS.

Comments?

 Jocke

> -----Original Message-----
> From: linux-mtd-admin at lists.infradead.org
> [mailto:linux-mtd-admin at lists.infradead.org]On Behalf Of Joakim
> Tjernlund
> Sent: Thursday, February 21, 2002 23:44
> To: David Woodhouse
> Cc: linux-mtd at lists.infradead.org
> Subject: Re: jffs2_scan_make_ino_cache() in scan.c very slow, new
> improvment
> 
> 
> Is the CRC check needed for the data part(if (ri.csize ....) in
> jffs2_scan_inode_node ()
> in ? Removing this check halves my already improved mount time :-)