I suddenly lost control over a partition. I was using it to download some data from internet. I manually aborted the download and when I tried to continue it the error message I got informed me I had no rights to write to the destination partition.

I checked fstab.
looks fine + has worked ok so far.

just in case I tried to umount and remount, but:
so I tried to kill anything that might be accessing the drive:

still nothing. Umounting as root gives the same error message.
I could of course reboot, but that's the cheap way out. How do I regain control over my partition?

you have done very well so far.....a tip in case its simply this...
close down all file managers and consoles or shells that may inadvertely been browsing your target partition then re-run your beautiful commands and see it that makes a diff.

You are correct to assume something is still using it so umount fails.

This is getting weirder and weirder: after a new clean boot I get the same error message for both hda6 and hda7.

They are both fat partitions which are symlinked into my /home partition (there's one more, but it has no symlinks and is unaffected).

The reason why I tried to umount in the first place was a write problem informed by HTTrack (web copy tool) so I tried to alter fstab to coincide with hda7, which was different due to rw problems with amule (uid=501,gid=501,umask=000,utf8,exec,dev,suid,rw). Since I couldn't umount I had to reboot, but I can now write to hda6 again.

Still, I see no reason why I shouldn't be able to umount a volume with symlinks if those links are not being used - there is only data on those partitions (one for mirrored websites and one for media) and no config files.

picture this and change the guilty if you agree...

/home/myname/folder link to hda6
/home/myetc/link to hda7

now redo the umount using the true path
umount /home/myname/link to hda6 etc and see if you have better luck?

and for extra luck close down all files that are writing to it and cd out of it so if
pwd......../home/myname/link to hda6 then
cd /
should help

WIth only a terminal open after a clean boot:

[root@linmix linmix]# umount /home/linmix/websites/
umount: /mnt/windows/e: device is busy
umount: /mnt/windows/e: device is busy

??? (thanks for thinking of something anyway)

ok if you are still interested.....using root powers edit your /etc/fstab file and delete those windows entries then reboot and now mount them manually.

then redo umount to see if that works.....if it does maybe there is something in your mtab or another program grabbing it like some audio group etc?

I'll comment them out (just in case) and see what happens - I sure would like to learn what's going on. I'll post the resoults as soon as I get a chance.

tried your suggestion , but haven't ben able to detect any anomlies. Everthing works as expected after reboot. No more trouble, but also no explanation/answer to my questions. pity I couldn't find out. ANyway, as long as everything works again and the problem doesn't come back I suppose I shouldn't complain.