ext3 reservation strangeness?!

[Karl Vogel]

When copying a file on 2.6.9-mm1 with the ext3 reservation code,
I noticed that there were a lot of fragments. Doing the same when
the filesystem is mounted with 'noreservation' seems to produce
better results?! Or am I interpreting this incorrectly?

Example:

[root@kvo kvo]# ls -l t
-rw-r--r--  1 root root 8228490 Oct 23 14:45 t

Copying this file with reservation code active:

[root@kvo kvo]# mount -t ext3 -o commit=60,reservation /dev/sda1 /mnt
[root@kvo kvo]# cp t /mnt
[root@kvo kvo]# filefrag /mnt/t
/mnt/t: 129 extents found, perfection would be 1 extent
[root@kvo kvo]# rm -f /mnt/t
[root@kvo kvo]# umount /mnt

While doing the same with 'noreservation' produces only 2 extents:

[root@kvo kvo]# mount -t ext3 -o commit=60,noreservation /dev/sda1 /mnt
[root@kvo kvo]# cp t /mnt
[root@kvo kvo]# filefrag /mnt/t
/mnt/t: 2 extents found, perfection would be 1 extent
[root@kvo kvo]# rm -f /mnt/t


There was enough free diskspace available:

[root@kvo kvo]# df /mnt
Filesystem           1K-blocks      Used Available Use% Mounted on
/dev/sda1             76904352  25383252  47614496  35% /mnt

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