Re: [PATCH 2/2] ovl: implement async IO routines

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> >>
> >> Refer to function generic_file_read_iter(), in direct IO path,
> >> file_accessed() is done before IO submission, so I think ovl_file_accessed()
> >> should be done here no matter completion/error or IO is queued.
> >
> > Mmm, it doesn't matter much if atime is updated before or after,
> > but ovl_file_accessed() does not only update atime, it also copies
> > ctime which could have been modified as a result of the io, so
> > I think it is safer to put it in the cleanup hook.
> >
>
> Can you give a more detailed description that a read op will modify
> ctime as a result of the io?
>
> I found that it will trigger BUG_ON(irqs_disabled()) while
> calling ovl_file_accessed() on async IO return path. The calltrace
> is pasted below:
>
> ovl_file_accessed
>   -> touch_atime
>     -> ovl_update_time
>       -> generic_update_time
>         -> __mark_inode_dirty
>           -> ext4_dirty_inode
>             -> __ext4_get_inode_loc
>               -> __find_get_block
>                 -> lookup_bh_lru
>                    -> check_irqs_on
>
> So I need more detail to find how to fix this issue.
>

It's not important. Please ignore. I din't know there was an issue
with placing touch_atime() in completion context.

Thanks,
Amir.



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