lkml.org 
[lkml]   [2016]   [Feb]   [24]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] ext2, ext4: Fix issue with missing journal entry
On Thu, Jan 28, 2016 at 09:32:11AM -0700, Ross Zwisler wrote:
> On Thu, Jan 28, 2016 at 02:16:30PM +0100, Jan Kara wrote:
> > On Wed 27-01-16 12:01:48, Ross Zwisler wrote:
> > > As it is currently written ext4_dax_mkwrite() assumes that the call into
> > > __dax_mkwrite() will not have to do a block allocation so it doesn't create
> > > a journal entry. For a read that creates a zero page to cover a hole
> > > followed by a write that actually allocates storage this is incorrect. The
> > > ext4_dax_mkwrite() -> __dax_mkwrite() -> __dax_fault() path calls
> > > get_blocks() to allocate storage.
> > >
> > > Fix this by having the ->page_mkwrite fault handler call ext4_dax_fault()
> > > as this function already has all the logic needed to allocate a journal
> > > entry and call __dax_fault().
> > >
> > > Also update the ext2 fault handlers in this same way to remove duplicate
> > > code and keep the logic between ext2 and ext4 the same.
> > >
> > > Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
> >
> > Ah, ok, you are right. The patch looks good but Matthew is reworking the
> > area more (so ext4_da_mkwrite() is likely to return) so it this worth it?
> > Or do you expect Matthew's patches to land much later?
>
> Yep, Matthew is in the process of reworking all of the DAX fault handling.
>
> I was thinking that we might want to take this patch for v4.5, since it fixes
> a bug that I'm guessing could lead to some sort of corruption (lack of a
> journal entry entry for an allocating write), and then Matthew's reworks would
> land in v4.6?

Hey Jan,

Looks like this patch didn't ever get merged for v4.5? Is it still queued for
v4.6?

Thanks,
- Ross

\
 
 \ /
  Last update: 2016-02-24 22:21    [W:0.146 / U:0.264 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site