Re: [PATCH 23/25] xfs: connect up write verifiers to new buffers

Dave Chinner
2012-10-30T22:32:50Z

On Tue, Oct 30, 2012 at 06:39:38AM -0700, Phil White wrote:
> On Thu, Oct 25, 2012 at 05:34:12PM +1100, Dave Chinner wrote:
> > From: Dave Chinner <dchinner@redhat.com>
> >
> > Metadata buffers that are read from disk have write verifiers
> > already attached to them, but newly allocated buffers do not. Add
> > appropriate write verifiers to all new metadata buffers.
> >
> > Signed-off-by: Dave Chinner <dchinner@redhat.com>
> > ---
> > fs/xfs/xfs_alloc.c | 6 +--
> > fs/xfs/xfs_alloc.h | 2 +
> > fs/xfs/xfs_alloc_btree.c | 1 +
> > fs/xfs/xfs_attr_leaf.c | 4 +-
> > fs/xfs/xfs_bmap.c | 2 +
> > fs/xfs/xfs_bmap_btree.c | 3 +-
> > fs/xfs/xfs_bmap_btree.h | 1 +
> > fs/xfs/xfs_btree.c | 1 +
> > fs/xfs/xfs_btree.h | 2 +
> > fs/xfs/xfs_da_btree.c | 3 ++
> > fs/xfs/xfs_dir2_block.c | 2 +
> > fs/xfs/xfs_dir2_data.c | 11 +++--
> > fs/xfs/xfs_dir2_leaf.c | 19 ++++++---
> > fs/xfs/xfs_dir2_node.c | 24 +++++++----
> > fs/xfs/xfs_dir2_priv.h | 2 +
> > fs/xfs/xfs_dquot.c | 104 ++++++++++++++++++++++-----------------------
> > fs/xfs/xfs_fsops.c | 7 ++-
> > fs/xfs/xfs_ialloc.c | 5 ++-
> > fs/xfs/xfs_ialloc.h | 4 +-
> > fs/xfs/xfs_ialloc_btree.c | 1 +
> > fs/xfs/xfs_inode.c | 14 +++++-
> > fs/xfs/xfs_inode.h | 1 +
> > fs/xfs/xfs_mount.c | 2 +-
> > fs/xfs/xfs_mount.h | 1 +
> > 24 files changed, 135 insertions(+), 87 deletions(-)
> >
>
> A few comments:
>
> > diff --git a/fs/xfs/xfs_attr_leaf.c b/fs/xfs/xfs_attr_leaf.c
> > index bb96c55..5d56886 100644
> > --- a/fs/xfs/xfs_attr_leaf.c
> > +++ b/fs/xfs/xfs_attr_leaf.c
> > @@ -923,7 +923,7 @@ xfs_attr_leaf_to_node(xfs_da_args_t *args)
> > XFS_ATTR_FORK);
> > if (error)
> > goto out;
> > - ASSERT(bp2 != NULL);
> > + bp2->b_pre_io = bp1->b_pre_io;
> > memcpy(bp2->b_addr, bp1->b_addr, XFS_LBSIZE(dp->i_mount));
> > bp1 = NULL;
> > xfs_trans_log_buf(args->trans, bp2, 0, XFS_LBSIZE(dp->i_mount) - 1);
> > @@ -977,7 +977,7 @@ xfs_attr_leaf_create(
> > XFS_ATTR_FORK);
> > if (error)
> > return(error);
> > - ASSERT(bp != NULL);
> > + bp->b_pre_io = xfs_attr_leaf_write_verify;
> > leaf = bp->b_addr;
> > memset((char *)leaf, 0, XFS_LBSIZE(dp->i_mount));
> > hdr = &leaf->hdr;
>
> I'm unclear as to why you're removing the asserts here. There must be
> a reason that you think bp is guaranteed to be safe, but I haven't
> grasped it here.

If bp is NULL then the code is going to oops immediately, anyway.
Hence the assert is redundant. Further, the function that returns
bp either gives us a valid buffer or returns an error, so logically
the assert is also redundant from that perspective.

Hence I killed them to clean up the code a little.

Cheers,

Dave.
--
Dave Chinner
david@fromorbit.com