Re: [Ext4 Secure Delete 7/7v4] ext4/jbd2: Secure Delete: Secure delete journal blocks

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Mon, 10 Oct 2011 16:35:24 -0700
Allison Henderson <achender@xxxxxxxxxxxxxxxxxx> wrote:

> On 10/10/2011 12:47 PM, Jonathan Corbet wrote:
> > One quick question:
> >
> > On Fri,  7 Oct 2011 00:11:05 -0700
> > Allison Henderson<achender@xxxxxxxxxxxxxxxxxx>  wrote:
> >
> >> +	/* Secure delete any blocks still in our range */
> >> +	if (jbd2_pblk_count>  0)
> >> +		err = ext4_secure_delete_pblks(journal->j_inode,
> >> +			jbd2_pblk_start, jbd2_pblk_count);
> >> +
> >> +out:
> >> +	spin_unlock(&journal->j_pair_lock);
> >
> > ext4_secure_delete_pblks() appears to do its job synchronously - it has
> > calls to things like sync_dirty_buffer() and such.  How can you do that
> > while holding ->j_pair_lock?
> >
> > Thanks,
> >
> > jon
> >
> 
> Hi Jon,
> 
> Well j_pair_lock is a lock I added to protect the new list of vfs
> -> jbd2 block pairs. It is locked by the journal commit thread to
> update the list when ever a journal block is modified. The above
> code here is called by the same thread that performs a punch hole or
> truncate operation, not the journal commit thread. So I'm not
> immediately seeing why there would be any lock problems. Is there
> another case I'm missing?

The problem is that ext4_secure_delete_pblks() can sleep, unless I've
misunderstood things very badly.  That's not something you want to do
while holding a spinlock...

jon
--
To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html


[Index of Archives]     [Linux Ext4 Filesystem]     [Union Filesystem]     [Filesystem Testing]     [Ceph Users]     [Ecryptfs]     [AutoFS]     [Kernel Newbies]     [Share Photos]     [Security]     [Netfilter]     [Bugtraq]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux Cachefs]     [Reiser Filesystem]     [Linux RAID]     [Samba]     [Device Mapper]     [CEPH Development]
  Powered by Linux