Re: reiserfs+acl makes processes hang?

[Jeff Mahoney <jeffm@suse.com>]

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Tarmo Tänav wrote:
> 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.
> 
> 

Ok, this is due to the iput in the reiserfs_new_inode failure path
calling reiserfs_delete_xattrs with the lock already held.

I'll post a patch soon.

- -Jeff

- --
Jeff Mahoney
SuSE Labs
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