Re: 2.0.31-pre9: "noise after df"

Pavel Machek (pavel@Elf.mj.gts.cz)
Mon, 15 Sep 1997 13:38:57 +0200

> (If I'm the only one to debug with ears, please excuse)
> I think that "df" makes more noise on my harddisk than previous (i.e.
> 2.0.30) kernels.
>
> Can it be that some metadata is never written back to disk unless a
> "df" (or manual sync()) is done? My ears suggest that more data is
> written back now...
>
> Maybe someone can check it. And you can send me the CD "The sounds of
> the most popular harddisks"... ;-)

Hmm. Recreated in 2.1.55, df sounds like sync... And looks like sync,
too (on blinkenlights)... And guess what:

And it is because df _calls_ sync!

write(1, "Filesystem 1024-blocks "..., 67Filesystem
1024-blocks Used Available Capacity Mounted on
) = 67
sync() = 0
statfs("/", {f_type=EXT2_SUPER_MAGIC, f_bsize=1024, f_blocks=491660,
f_bfree=21860, f_files=127472, f_ffree=89438, f_namelen=255}}) = 0
write(1, "/dev/hda4 491660 46"..., 58/dev/hda4
491660 469800 16780 97%

So "bug" is in df (or is sync required before df-ing?).
Pavel

-- 
I'm really pavel@atrey.karlin.mff.cuni.cz. 	   Pavel
Look at http://atrey.karlin.mff.cuni.cz/~pavel/ ;-).