Re: [PATCH 3/5] xfs: separate the dqrele_all inode grab logic from xfs_inode_walk_ag_grab

["Darrick J. Wong" <djwong@kernel.org>]

On Wed, Jun 02, 2021 at 07:40:27AM +1000, Dave Chinner wrote:
> On Tue, Jun 01, 2021 at 12:50:51PM -0700, Darrick J. Wong wrote:
> > On Tue, Jun 01, 2021 at 10:20:23AM +1000, Dave Chinner wrote:
> > > On Mon, May 31, 2021 at 03:41:07PM -0700, Darrick J. Wong wrote:
> > > > From: Darrick J. Wong <djwong@kernel.org>
> > > > 
> > > > Disentangle the dqrele_all inode grab code from the "generic" inode walk
> > > > grabbing code, and and use the opportunity to document why the dqrele
> > > > grab function does what it does.
> > > > 
> > > > Since dqrele_all is the only user of XFS_ICI_NO_TAG, rename it to
> > > > something more specific for what we're doing.
> > > > 
> > > > Signed-off-by: Darrick J. Wong <djwong@kernel.org>
> > > > ---
> > > >  fs/xfs/xfs_icache.c |   64 ++++++++++++++++++++++++++++++++++++++++++++++++---
> > > >  fs/xfs/xfs_icache.h |    4 ++-
> > > >  2 files changed, 62 insertions(+), 6 deletions(-)
> > > > 
> > > > 
> > > > diff --git a/fs/xfs/xfs_icache.c b/fs/xfs/xfs_icache.c
> > > > index 34b8b5fbd60d..5501318b5db0 100644
> > > > --- a/fs/xfs/xfs_icache.c
> > > > +++ b/fs/xfs/xfs_icache.c
> > > > @@ -26,6 +26,8 @@
> > > >  
> > > >  #include <linux/iversion.h>
> > > >  
> > > > +static bool xfs_dqrele_inode_grab(struct xfs_inode *ip);
> > > > +
> > > 
> > > Just mov the function higher up in the file rather than add forward
> > > declarations....
> > 
> > Ugh, this will cause churn that will ripple through this and the next
> > iwalk refactoring patchsets and deferred inactivation.  Can I please
> > please please defer the churn cleanup until the end of all that?
> 
> Yes, by all means. I don't want to make it harder to get stuff done,
> so moving stuff around at the end of the series is fine...
> 
> ....

In the end it was easy enough to do it (as a separate prep patch) once I
concluded that separate the goal of the inode_walk from the radix tree
tags to eliminate the confusing XFS_ICI_NONTAG cases (i.e. quotaoff).

> > > This is basically just duplication of xfs_inode_walk_ag_grab()
> > > without the XFS_INODE_WALK_INEW_WAIT check in it. At this point I
> > > just don't see a reason for this function or the
> > > XFS_ICI_DQRELE_NONTAG rename just to use this grab function...
> > 
> > Ugh.  I should have sent the /next/ iwalk refactoring series along with
> > this one so that it would become more obvious that the end goal is to
> > seal all the incore inode walk code in xfs_icache.c, since there are
> > only four of them (reclaim, inodegc, blockgc, quotaoff) and the grab
> > functions for all four are just different enough that it's not really
> > worth it to keep them combined in one function full of conditionals.
> > 
> > Once that's done, the only user of xfs_inode_walk_ag_grab is the blockgc
> > code and I can rename it.
> 
> Ok, that context is missing from the patch series. :/

Sorry.

> > Ofc the reason I held back is that the next series adds 8 more iwalk
> > cleanup patches, and the more patches I send all at once the longer it
> > takes for anyone to start looking at it.  I /still/ can't figure out the
> > balance between risking overwhelming everyone with too many patches vs.
> > sending insufficient patches to convey where I'm really going with
> > something.
> 
> Yeah, can be difficult. I prefer to err on the side of "complete
> change" rather than splitting two parts of a larger work
> arbitrarily...

<nod> I'll combine this set and the next one when I resend this patch
pile.

> > <shrug> I might just ping you on irc so that we can have a conversation
> > about this and summarize whatever we come up with for the list.
> 
> You've got a branch with the full series in it somewhere, I'm
> guessing? point me at it so I can see where this ends up....

Yup.

https://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfs-linux.git/log/?h=inode-walk-cleanups-5.14

--D

> 
> Cheers,
> 
> Dave.
> -- 
> Dave Chinner
> david@fromorbit.com