From: Brian Foster <bfoster@redhat.com>
To: Allison Collins <allison.henderson@oracle.com>
Cc: linux-xfs@vger.kernel.org
Subject: Re: [PATCH v7 12/19] xfs: Add helper function xfs_attr_rmtval_unmap
Date: Wed, 26 Feb 2020 08:47:58 -0500 [thread overview]
Message-ID: <20200226134758.GA19695@bfoster> (raw)
In-Reply-To: <bcb14769-5f5e-4983-9413-f4fa03e921dc@oracle.com>
On Tue, Feb 25, 2020 at 08:29:06PM -0700, Allison Collins wrote:
>
>
> On 2/25/20 6:27 AM, Brian Foster wrote:
> > On Mon, Feb 24, 2020 at 02:44:14PM -0700, Allison Collins wrote:
> > >
> > >
> > > On 2/24/20 6:40 AM, Brian Foster wrote:
> > > > On Sat, Feb 22, 2020 at 07:06:04PM -0700, Allison Collins wrote:
> > > > > This function is similar to xfs_attr_rmtval_remove, but adapted to return EAGAIN for
> > > > > new transactions. We will use this later when we introduce delayed attributes
> > > > >
> > > > > Signed-off-by: Allison Collins <allison.henderson@oracle.com>
> > > > > ---
> > > > > fs/xfs/libxfs/xfs_attr_remote.c | 28 ++++++++++++++++++++++++++++
> > > > > fs/xfs/libxfs/xfs_attr_remote.h | 1 +
> > > > > 2 files changed, 29 insertions(+)
> > > > >
> > > > > diff --git a/fs/xfs/libxfs/xfs_attr_remote.c b/fs/xfs/libxfs/xfs_attr_remote.c
> > > > > index 3de2eec..da40f85 100644
> > > > > --- a/fs/xfs/libxfs/xfs_attr_remote.c
> > > > > +++ b/fs/xfs/libxfs/xfs_attr_remote.c
> > > > > @@ -711,3 +711,31 @@ xfs_attr_rmtval_remove(
> > > > > }
> > > > > return 0;
> > > > > }
> > > > > +
> > > > > +/*
> > > > > + * Remove the value associated with an attribute by deleting the out-of-line
> > > > > + * buffer that it is stored on. Returns EAGAIN for the caller to refresh the
> > > > > + * transaction and recall the function
> > > > > + */
> > > > > +int
> > > > > +xfs_attr_rmtval_unmap(
> > > > > + struct xfs_da_args *args)
> > > > > +{
> > > > > + int error, done;
> > > > > +
> > > > > + /*
> > > > > + * Unmap value blocks for this attr. This is similar to
> > > > > + * xfs_attr_rmtval_remove, but open coded here to return EAGAIN
> > > > > + * for new transactions
> > > > > + */
> > > > > + error = xfs_bunmapi(args->trans, args->dp,
> > > > > + args->rmtblkno, args->rmtblkcnt,
> > > > > + XFS_BMAPI_ATTRFORK, 1, &done);
> > > > > + if (error)
> > > > > + return error;
> > > > > +
> > > > > + if (!done)
> > > > > + return -EAGAIN;
> > > > > +
> > > > > + return 0;
> > > > > +}
> > > >
> > > > Hmm.. any reason this isn't a refactor of the existing remove function?
> > > > Just skipping to the end of the series, I see we leave the reference to
> > > > xfs_attr_rmtval_remove() (which no longer exists and so is not very
> > > > useful) in this comment as well as a stale function declaration in
> > > > xfs_attr_remote.h.
> > > >
> > > > I haven't grokked how this is used yet, but it seems like it would be
> > > > more appropriate to lift out the transaction handling from the original
> > > > function as we have throughout the rest of the code. That could also
> > > > mean creating a temporary wrapper (i.e., rmtval_remove() calls
> > > > rmtval_unmap()) for the loop/transaction code that could be removed
> > > > later if it ends up unused. Either way is much easier to follow than
> > > > creating a (currently unused) replacement..
> > > Yes, this came up in one of the other reviews. I thought about it, but then
> > > decided against it. xfs_attr_rmtval_remove disappears across patches 13 and
> > > 14. The use of xfs_attr_rmtval_remove is replaced with
> > > xfs_attr_rmtval_unmap when we finally yank out all the transaction code.
> > > The reason I dont want to do it all at once is because that would mean
> > > patches 12, 13, 14 and 19 would lump together to make the swap instantaneous
> > > in once patch.
> > >
> >
> > Hmm.. I don't think we're talking about the same thing. If
> > xfs_attr_rmtval_remove() was broken down into two functions such that
> > one of the two looks exactly like the _unmap() variant, can't we just
> > remove the other half when it becomes unused and allow the _remove()
> > variant to exist with the implementation of _unmap() proposed here? This
> > seems fairly mechanical to me..
> Oh, I see what you mean. No, I had done a review of the uses of
> xfs_attr_rmtval_remove and realized that it appears in both the set and
> remove paths. We use it in the set path when we're doing a rename, and need
> to remove the old attr.
>
> So in patch 13, we replace xfs_attr_rmtval_remove with xfs_attr_rmtval_unmap
> for the remove routines. But it's still in the set routines. So we cant
> take it away yet. Once we get through patch 14, it is no longer used and we
> can remove it. Did that make sense?
>
I don't think you need to take it away in this patch. What I'm
suggesting is breaking existing code into something like this:
int
__xfs_attr_rmtval_remove()
{
...
error = xfs_bunmapi(...);
...
if (!done)
return -EAGAIN;
...
}
int
xfs_attr_rmtval_remove()
{
error = xfs_attr_rmtval_invalidate();
do {
error = __xfs_attr_rmtval_remove();
...
xfs_defer_finish();
...
xfs_trans_roll_inode(...);
} while (-EAGAIN);
...
}
So we can continue to use both as needed without duplication and remove
the bits that become unused as the series progresses. Eventually we
could rename __xfs_attr_rmtval_remove() back to xfs_attr_rmtval_remove()
to maintain that it's essentially the same function and only the
transaction rolling bits are being factored out and eventually removed.
Brian
> >
> > > I've been getting feedback that the set is really complicated, so I've been
> > > trying to find a way to organize it to help make it easier to review. So I
> > > thought isolating 13 and 14 to just the state machine would help. Thus I
> > > decided to keep patch 12 separate to take as much craziness out of 13 and 14
> > > as possible. Patches 12 and 19 seem like otherwise easy things for people
> > > to look at. Let me know your thoughts on this. :-)
> > >
> >
> > I think doing as much refactoring of existing code as early as possible
> > will go a long way towards simplifying the complexity around the
> > introduction of the state bits.
>
> Alrighty, I was thinking that if I reordered things such that modularizing
> appeared at the end of the set, that it would help people to see it in
> context with the states. But it sounds like people like it the other way
> around, it's easy enough to put back. Though I think we may still be stuck
> with 12 and 19 being apart unless 13 and 14 come together. :-(
>
> Allison
>
> >
> > Brian
> >
> > > You are right about the stale comment though, I missed it while going back
> > > over the commentary at the top. Will fix.
> > >
> > > Allison
> > >
> > > >
> > > > Brian
> > > >
> > > > > diff --git a/fs/xfs/libxfs/xfs_attr_remote.h b/fs/xfs/libxfs/xfs_attr_remote.h
> > > > > index eff5f95..e06299a 100644
> > > > > --- a/fs/xfs/libxfs/xfs_attr_remote.h
> > > > > +++ b/fs/xfs/libxfs/xfs_attr_remote.h
> > > > > @@ -14,4 +14,5 @@ int xfs_attr_rmtval_remove(struct xfs_da_args *args);
> > > > > int xfs_attr_rmtval_stale(struct xfs_inode *ip, struct xfs_bmbt_irec *map,
> > > > > xfs_buf_flags_t incore_flags);
> > > > > int xfs_attr_rmtval_invalidate(struct xfs_da_args *args);
> > > > > +int xfs_attr_rmtval_unmap(struct xfs_da_args *args);
> > > > > #endif /* __XFS_ATTR_REMOTE_H__ */
> > > > > --
> > > > > 2.7.4
> > > > >
> > > >
> > >
> >
>
next prev parent reply other threads:[~2020-02-26 13:48 UTC|newest]
Thread overview: 135+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-23 2:05 [PATCH v7 00/19] xfs: Delayed Ready Attrs Allison Collins
2020-02-23 2:05 ` [PATCH v7 01/19] xfs: Replace attribute parameters with struct xfs_name Allison Collins
2020-02-23 9:34 ` Amir Goldstein
2020-02-23 16:03 ` Allison Collins
2020-02-25 0:49 ` Dave Chinner
2020-02-24 12:08 ` Chandan Rajendra
2020-02-24 16:25 ` Allison Collins
2020-02-24 13:06 ` Brian Foster
2020-02-24 16:25 ` Allison Collins
2020-02-23 2:05 ` [PATCH v7 02/19] xfs: Embed struct xfs_name in xfs_da_args Allison Collins
2020-02-23 11:54 ` Amir Goldstein
2020-02-23 16:51 ` Allison Collins
2020-02-24 6:50 ` Amir Goldstein
2020-02-24 7:36 ` Allison Collins
2020-02-24 7:43 ` Amir Goldstein
2020-02-25 0:57 ` Dave Chinner
2020-02-25 2:00 ` Allison Collins
2020-02-25 4:06 ` Dave Chinner
2020-02-25 4:19 ` Allison Collins
2020-02-25 4:27 ` Darrick J. Wong
2020-02-25 6:07 ` Allison Collins
2020-02-25 6:30 ` Dave Chinner
2020-02-25 17:21 ` Christoph Hellwig
2020-02-25 6:56 ` Chandan Rajendra
2020-02-25 23:26 ` Allison Collins
2020-02-23 2:05 ` [PATCH v7 03/19] xfs: Add xfs_has_attr and subroutines Allison Collins
2020-02-23 12:20 ` Amir Goldstein
2020-02-23 17:28 ` Allison Collins
2020-02-24 6:58 ` Amir Goldstein
2020-02-25 6:26 ` Dave Chinner
2020-02-25 6:43 ` Amir Goldstein
2020-02-25 22:27 ` Dave Chinner
2020-02-24 13:08 ` Brian Foster
2020-02-24 21:18 ` Allison Collins
2020-02-25 13:25 ` Brian Foster
2020-02-26 2:31 ` Allison Collins
2020-02-25 9:49 ` Chandan Rajendra
2020-02-25 10:15 ` Chandan Rajendra
2020-02-26 2:19 ` Allison Collins
2020-02-26 2:18 ` Allison Collins
2020-02-23 2:05 ` [PATCH v7 04/19] xfs: Check for -ENOATTR or -EEXIST Allison Collins
2020-02-23 12:25 ` Amir Goldstein
2020-02-23 17:33 ` Allison Collins
2020-02-24 13:08 ` Brian Foster
2020-02-24 21:18 ` Allison Collins
2020-02-23 2:05 ` [PATCH v7 05/19] xfs: Factor out new helper functions xfs_attr_rmtval_set Allison Collins
2020-02-25 12:53 ` Chandan Rajendra
2020-02-26 2:20 ` Allison Collins
2020-02-23 2:05 ` [PATCH v7 06/19] xfs: Factor out trans handling in xfs_attr3_leaf_flipflags Allison Collins
2020-02-23 12:30 ` Amir Goldstein
2020-02-23 17:36 ` Allison Collins
2020-02-28 4:56 ` Chandan Rajendra
2020-02-23 2:05 ` [PATCH v7 07/19] xfs: Factor out xfs_attr_leaf_addname helper Allison Collins
2020-02-23 12:42 ` Amir Goldstein
2020-02-23 18:38 ` Allison Collins
2020-02-24 6:38 ` Amir Goldstein
2020-02-24 7:09 ` Allison Collins
2020-02-24 7:27 ` Amir Goldstein
2020-02-25 6:42 ` Dave Chinner
2020-02-25 13:26 ` Brian Foster
2020-02-25 23:26 ` Allison Collins
2020-02-28 6:51 ` Chandan Rajendra
2020-02-23 2:06 ` [PATCH v7 08/19] xfs: Refactor xfs_attr_try_sf_addname Allison Collins
2020-02-23 13:04 ` Amir Goldstein
2020-02-23 17:51 ` Allison Collins
2020-02-24 13:08 ` Brian Foster
2020-02-24 21:19 ` Allison Collins
2020-02-28 7:42 ` Chandan Rajendra
2020-02-28 18:14 ` Allison Collins
2020-02-23 2:06 ` [PATCH v7 09/19] xfs: Factor out trans roll from xfs_attr3_leaf_setflag Allison Collins
2020-02-28 7:59 ` Chandan Rajendra
2020-02-23 2:06 ` [PATCH v7 10/19] xfs: Factor out xfs_attr_rmtval_invalidate Allison Collins
2020-02-28 10:42 ` Chandan Rajendra
2020-02-23 2:06 ` [PATCH v7 11/19] xfs: Factor out trans roll in xfs_attr3_leaf_clearflag Allison Collins
2020-02-28 10:56 ` Chandan Rajendra
2020-02-23 2:06 ` [PATCH v7 12/19] xfs: Add helper function xfs_attr_rmtval_unmap Allison Collins
2020-02-24 13:40 ` Brian Foster
2020-02-24 21:44 ` Allison Collins
2020-02-25 13:27 ` Brian Foster
2020-02-26 3:29 ` Allison Collins
2020-02-26 13:47 ` Brian Foster [this message]
2020-02-25 7:21 ` Dave Chinner
2020-02-25 23:27 ` Allison Collins
2020-02-28 14:22 ` Chandan Rajendra
2020-02-23 2:06 ` [PATCH v7 13/19] xfs: Add delay ready attr remove routines Allison Collins
2020-02-24 15:25 ` Brian Foster
2020-02-24 17:03 ` Brian Foster
2020-02-24 23:14 ` Allison Collins
2020-02-24 23:56 ` Darrick J. Wong
2020-02-25 13:34 ` Brian Foster
2020-02-26 5:36 ` Allison Collins
2020-02-26 13:48 ` Brian Foster
2020-02-26 19:23 ` Allison Collins
2020-02-25 8:57 ` Dave Chinner
2020-02-26 0:57 ` Allison Collins
2020-02-26 22:34 ` Dave Chinner
2020-02-27 4:18 ` Allison Collins
2020-03-03 5:03 ` Chandan Rajendra
2020-03-03 5:40 ` Allison Collins
2020-02-23 2:06 ` [PATCH v7 14/19] xfs: Add delay ready attr set routines Allison Collins
2020-03-03 13:41 ` Chandan Rajendra
2020-03-03 17:07 ` Allison Collins
2020-02-23 2:06 ` [PATCH v7 15/19] xfs: Add helper function xfs_attr_node_shrink Allison Collins
2020-02-23 13:22 ` Amir Goldstein
2020-02-23 18:41 ` Allison Collins
2020-02-25 9:05 ` Dave Chinner
2020-02-26 1:48 ` Allison Collins
2020-02-23 2:06 ` [PATCH v7 16/19] xfs: Simplify xfs_attr_set_iter Allison Collins
2020-02-23 13:26 ` Amir Goldstein
2020-02-23 18:42 ` Allison Collins
2020-02-25 9:21 ` Dave Chinner
2020-02-26 2:13 ` Allison Collins
2020-02-26 22:39 ` Dave Chinner
2020-03-04 4:30 ` Chandan Rajendra
2020-03-04 17:04 ` Allison Collins
2020-03-05 3:39 ` Chandan Rajendra
2020-02-23 2:06 ` [PATCH v7 17/19] xfs: Add helper function xfs_attr_leaf_mark_incomplete Allison Collins
2020-02-23 13:47 ` Amir Goldstein
2020-02-23 18:43 ` Allison Collins
2020-02-25 9:31 ` Dave Chinner
2020-02-26 2:17 ` Allison Collins
2020-03-04 4:37 ` Chandan Rajendra
2020-02-23 2:06 ` [PATCH v7 18/19] xfs: Add remote block helper functions Allison Collins
2020-02-23 13:45 ` Amir Goldstein
2020-03-04 4:59 ` Chandan Rajendra
2020-02-23 2:06 ` [PATCH v7 19/19] xfs: Remove xfs_attr_rmtval_remove Allison Collins
2020-02-23 13:54 ` Amir Goldstein
2020-02-23 18:50 ` Allison Collins
2020-02-23 7:55 ` [PATCH v7 00/19] xfs: Delayed Ready Attrs Amir Goldstein
2020-02-23 16:02 ` Allison Collins
2020-02-24 6:30 ` Amir Goldstein
2020-02-24 16:23 ` Allison Collins
2020-02-25 5:53 ` Amir Goldstein
2020-02-24 8:31 ` Chandan Rajendra
2020-02-25 9:52 ` Dave Chinner
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