Re: BUG: reiserfs+acl+quota deadlock

[Jeff Mahoney <jeffm@suse.com>]

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Vladimir V. Saveliev wrote:
> Hello
> 
> Jan Kara wrote:
>>> Tried the attached patch but it changed nothing, I trying to create
>>> a new file as a user whose quota grace time has ran out will still
>>> cause everything accessing the users homedir (the one with the quota)
>>> to hang in D state.
>>>
>>> Also note that the bug I reported only exists when acl is also
>>> enabled (does not have to be used). And although my kernel is not
>>> built with debug (or reiserfs debug) support, I don't get any
>>> oopses or reiserfs errors.. it just hangs.
>>
> 
> It looks like the problem is that reiserfs_new_inode can be called
> either having xattrs locked or not.
> It does unlocking/locking xattrs on error handling path, but has no idea
> about whether
> xattrs are locked of not.
> The attached patch seems to fix the problem.
> I am not sure whether it is correct way to fix this problem, though.

Does this patch actually fix it? It shouldn't.

The logic is like this: If a default ACL is associated with the parent
when the inode is created, xattrs will be locked so that the ACL can be
inherited. Since reiserfs_new_inode is called from the VFS layer with
inode->i_sem downed, {set,remove}xattr is locked out. The default ACL
can't be removed/added/changed while reiserfs_new_inode is running.
Therefore, if there is a default ACL, xattrs must be locked.

- -Jeff

- --
Jeff Mahoney
SuSE Labs
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