Re: [BK][PATCH] Reiser4, will double Linux FS performance, pleaseapply

[Nikita Danilov]

Tomas Szepe writes:
 > > This should help:
 > > 
 > > diff -Nru a/txnmgr.c b/txnmgr.c
 > > --- a/txnmgr.c	Wed Oct 30 18:58:09 2002
 > > +++ b/txnmgr.c	Fri Nov  1 20:13:27 2002
 > > @@ -1917,7 +1917,7 @@
 > >  		return;
 > >  	}
 > >  
 > > -	if (!jnode_is_unformatted) {
 > > +	if (jnode_is_znode(node)) {
 > >  		if ( /**jnode_get_block(node) &&*/
 > >  			   !blocknr_is_fake(jnode_get_block(node))) {
 > >  			/* jnode has assigned real disk block. Put it into
 > 
 > 
 > Jup, this fixes the leak, but free space still isn't reported accurately
 > until after sync gets called, which I believe is a bug too.

In reiser4 allocation of disk space is delayed to transaction commit. It
is not possible to estimate precisely amount of disk space that will be
allocated during commit, and hence statfs(2) results are not updated
until one does sync(2) (forcing commit) or transaction is committed due
to age (10 minutes by default).

 > 
 > Compare:
 > [reiser3]
 > $ pwd
 > /tmp
 > $ dd if=/dev/zero of=testfile bs=16k count=64
 > 64+0 records in
 > 64+0 records out
 > $ df /
 > Filesystem           1k-blocks      Used Available Use% Mounted on
 > /dev/sda1               526296    330696    195600  63% /
 > $ rm testfile
 > $ df /
 > Filesystem           1k-blocks      Used Available Use% Mounted on
 > /dev/sda1               526296    329672    196624  63% /
 > $ sync
 > $ df /

[...]

Nikita.