[MiNT] ext2 reserved block bug

[Martin-Éric Racine <q-funk@pp.fishpool.fi>]

On 2000-4-10, Frank Naumann <fnaumann@freemint.de> wrote:

> > [ Error writing to /home/q-funk/#pico00120#: no space on device ]
> > 
> > There is currently 23 MB free on this partition, so...
>  
> You know that ext2 have super user reserved number of blocks?
> With tune2fs you can manipulate these value. Default is 5%
> from the total number of blocks of the filesystem.

Right and dump2fs says:

Inode count:              128016
Block count:              511754
Reserved block count:     25587
Free blocks:              24711
Free inodes:              119001
First block:              1
Reserved blocks uid:      0 (user root)
Reserved blocks gid:      0 (group root)

...the number of free blocks is just below the number of reserved
blocks.  Thing evaluates the partition is filled at 95% also,
which confirms the 5% default is in place.

However, it seems this is ignored by older binaries, probably
because older libraries allowed ignoring filesystem warnings.

What purpose do these reserved blocks serve?  Are they used to
store the bitmap information or anything else vital to the
filesystem maintenance?

-- 
Martin-Éric Racine  http://funkyware.atari.org/  Atari TT030 FAQ
Lappeenranta, Finland.  Surfing on a Intel/Microsoft-free GEM OS