reiserfs+acl makes processes hang?

["Tarmo Tänav" <tarmo@itech.ee>]

Hi,

(I've already sent this to lkml and the bug has been confirmed
a couple of times, but I though I should also send it to
reiserfs-list so here goes:)


I think I've found a bug in reiserfs acls. If triggered
it means that any program trying to access the partition,
where the bug occured, will just hang in D state, with
no way to kill the program.

Here's how to reproduce:
1. mount a reiserfs volume (loopmount will do) with "-o acl".
2. create a directory "dir"
3. set some default acl: setfacl -d -m u:username:rwX dir
4. cd dir
5. dd if=/dev/zero of=somefile1 bs=4k count=100000
(the idea is to run out of space)
6. now df should show 0 free space, if not then repeat 5.
7. echo "1" > somefile2 # this should hang infinitely

Now no program will be able to access the partition.

I haven't tried to reproduce it, but the same problem also happened
when a user hit his hard quota limit on my server. Then no program
could access his homedir.