On Mon, 2016-05-16 at 17:22 +0200, Jan Kara wrote:
> On Thu 12-05-16 12:45:22, Ross Zwisler wrote:
> >
> > On Wed, May 11, 2016 at 11:58:49AM +0200, Jan Kara wrote:
> > >
> > > Currently ext2 zeroes any data blocks allocated for DAX inode
> > > however it
> > > still returns them as BH_New. Thus DAX code zeroes them again in
> > > dax_insert_mapping() which can possibly overwrite the data that
> > > has been
> > > already stored to those blocks by a racing dax_io(). Avoid
> > > marking
> > > pre-zeroed buffers as new.
> > >
> > > Reviewed-by: Ross Zwisler <ross.zwisler@xxxxxxxxxxxxxxx>
> > > Signed-off-by: Jan Kara <jack@xxxxxxx>
> > > ---
> > > fs/ext2/inode.c | 4 ++--
> > > 1 file changed, 2 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/fs/ext2/inode.c b/fs/ext2/inode.c
> > > index 6bd58e6ff038..1f07b758b968 100644
> > > --- a/fs/ext2/inode.c
> > > +++ b/fs/ext2/inode.c
> > > @@ -745,11 +745,11 @@ static int ext2_get_blocks(struct inode
> > > *inode,
> > > mutex_unlock(&ei->truncate_mutex);
> > > goto cleanup;
> > > }
> > > - }
> > > + } else
> > > + set_buffer_new(bh_result);
> > >
> > > ext2_splice_branch(inode, iblock, partial,
> > > indirect_blks, count);
> > > mutex_unlock(&ei->truncate_mutex);
> > > - set_buffer_new(bh_result);
> > > got_it:
> > > map_bh(bh_result, inode->i_sb, le32_to_cpu(chain[depth-
> > > 1].key));
> > > if (count > blocks_to_boundary)
> > > --
> > > 2.6.6
> > Interestingly this change is causing a bunch of xfstests
> > regressions for me
> > with ext2 + DAX. All of these tests pass without this one change.
> Good catch. Attached patch fixes this issue for me. Preferably it
> should be
> merged before the above ext2 change.
>
> Honza
Hey Jan,
In my patch 3 of the error handling series, I have:
- err = dax_clear_sectors(inode->i_sb->s_bdev,
- le32_to_cpu(chain[depth-1].key) <<
- (inode->i_blkbits - 9),
- 1 << inode->i_blkbits);
+ err = sb_issue_zeroout(inode->i_sb,
+ le32_to_cpu(chain[depth-1].key), 1, GFP_NOFS);
Does this mean I have to change to send the sb_issue_zeroout for
'count' blocks.. i.e.
- err = dax_clear_sectors(inode->i_sb->s_bdev,
- le32_to_cpu(chain[depth-1].key) <<
- (inode->i_blkbits - 9),
- 1 << inode->i_blkbits);
+ err = sb_issue_zeroout(inode->i_sb,
+ le32_to_cpu(chain[depth-1].key), count, GFP_NOFS);
If so, I'll update my series tomorrow to include in both of these changes.
Thanks,
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