On Sat, Jun 17, 2017 at 08:39:53AM -0400, Jeff Layton wrote:
> On Fri, 2017-06-16 at 15:34 -0400, Jeff Layton wrote:
> > Jan Kara's description for this patch is much better than mine, so I'm
> > quoting it verbatim here:
> >
> > DAX currently doesn't set errors in the mapping when cache flushing
> > fails in dax_writeback_mapping_range(). Since this function can get
> > called only from fsync(2) or sync(2), this is actually as good as it can
> > currently get since we correctly propagate the error up from
> > dax_writeback_mapping_range() to filemap_fdatawrite()
> >
> > However, in the future better writeback error handling will enable us to
> > properly report these errors on fsync(2) even if there are multiple file
> > descriptors open against the file or if sync(2) gets called before
> > fsync(2). So convert DAX to using standard error reporting through the
> > mapping.
> >
> > Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx>
> > Reviewed-by: Jan Kara <jack@xxxxxxx>
> > Reviewed-by: Christoph Hellwig <hch@xxxxxx>
> > Reviewed-and-Tested-by: Ross Zwisler <ross.zwisler@xxxxxxxxxxxxxxx>
> > ---
> > fs/dax.c | 4 +++-
> > 1 file changed, 3 insertions(+), 1 deletion(-)
> >
> > diff --git a/fs/dax.c b/fs/dax.c
> > index 9899f07acf72..c663e8cc2a76 100644
> > --- a/fs/dax.c
> > +++ b/fs/dax.c
> > @@ -856,8 +856,10 @@ int dax_writeback_mapping_range(struct address_space *mapping,
> >
> > ret = dax_writeback_one(bdev, dax_dev, mapping,
> > indices[i], pvec.pages[i]);
> > - if (ret < 0)
> > + if (ret < 0) {
> > + mapping_set_error(mapping, ret);
> > goto out;
> > + }
> > }
> > }
> > out:
>
> I should point out here that Ross had an issue with this patch in an
> earlier set, that I addressed with a flag in the last set. The flag is
> icky though.
>
> In this set, patch #6 should make it unnecessary:
>
> mm: clear AS_EIO/AS_ENOSPC when writeback initiation fails
>
> Ross, could you test that this set still works ok for you with dax? It
> should apply reasonably cleanly on top of linux-next.
Yep, v7 passes my DAX testing.
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