On 11/30/2011 09:33 PM, Chris Dunlop wrote:
> On Wed, Nov 30, 2011 at 08:22:39PM -0600, Dave Kleikamp wrote:
>> On 11/30/2011 06:47 PM, Chris Dunlop wrote:
>>>> It's also worth printing a message - this *is* a kernel bug of some description
>>>> if it happens.
>>> Like the below? This covers the d_revalidate for 9p, afs, coda,
>>> hfs, ncpfs, proc, sysfs.
>>> Note: jfs isn't susceptible to this problem, but the resolution
>>> doesn't look like the other file systems, and from the comment
>>> I'm not sure if the problem was really understood and if it's
>>> doing the right thing:
>> This code, as well as the comments, were copied from vfat. It seems
>> reasonable for case-insensitive but case-preserving behavior (not jfs's
>> default). The safe thing is to drop the negative dentry if we don't know
>> the operation.
> In that case, it looks like the thing to do might be to add the
> "protection" to the start of jfs_ci_revaliate(), per how the
> original has been changed in vfat:
The LOOKUP_RCU check had previously been there, but Al Viro removed it:
Author: Al Viro <viro@zeni...>
Date: Sat Jun 25 21:41:09 2011 -0400
jfs_ci_revalidate() is safe from RCU mode
I'm not sure what it takes to be "safe", but this is a simple function
that doesn't block, take locks, or do much of anything. You shouldn't
need to do anything with jfs.