Re: squashfs size in statfs

[Phillip Lougher]

On 6/15/06, Jan Engelhardt <jengelh@xxxxxxxxxxxxxxx> wrote:
> >> Hello list,
> >>
> >>
> >> # l /mnt
> >> total 36293
> >> drwxr-xr-x   2 root root       20 Jun  5 11:50 .
> >> drwxr-xr-x  31 root root     4096 Jun  5  2006 ..
> >> -rw-r--r--   1 root root 37158912 Jun  5 11:06 mem
> >> # df
> >> Filesystem           1K-blocks      Used Available Use% Mounted on
> >> /dev/shm/sc.sqfs         26688     26688         0 100% /mnt
> >> # l sc.sqfs
> >> -rwx------  1 jengelh users 27279360 Jun  5 11:50 sc.sqfs
> >>
> >> I think statfs() should show the uncompressed size, no?
> >
> >No.
> >
> Yes, because CRAM does it that way, and maybe zisofs does it too:

Zisofs doesn't (H. Peter Anvin should know as he wrote it :-) ).

root@pierrot:/# ls -la dir.iso
-rw-r--r--  1 root root 366592 2006-06-16 22:41 dir.iso
root@pierrot:/# mount -t iso9660 dir.iso /mnt -o loop
root@pierrot:/# df /mnt
Filesystem           1K-blocks      Used Available Use% Mounted on
/dir.iso                   358       358         0 100% /mnt
root@pierrot:/# ls -la /mnt
total 13
drwxr-xr-x   2 root root     2048 2006-06-16 22:41 .
drwxr-xr-x  32 root root     4096 2006-06-16 22:56 ..
-rw-r--r--   1 root root 51200000 2006-06-16 22:40 zero

Statfs should return the size of the filesystem, not the amount of
data the filesystem  represents.  In this respect the behaviour of
Squashfs and Zisofs is correct.

This is analogous to performing stat on a gzipped file.  The stat
returns the size of the compressed file, not the uncompressed size.

Phillip
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