Re: [PATCH v11 00/25] xfs: Delay Ready Attributes

[Dave Chinner <david@fromorbit.com>]

On Fri, Jul 24, 2020 at 01:41:00PM +1000, Dave Chinner wrote:
> On Mon, Jul 20, 2020 at 05:15:41PM -0700, Allison Collins wrote:
> > Hi all,
> > 
> > This set is a subset of a larger series for delayed attributes. Which is a
> > subset of an even larger series, parent pointers. Delayed attributes allow
> > attribute operations (set and remove) to be logged and committed in the same
> > way that other delayed operations do. This allows more complex operations (like
> > parent pointers) to be broken up into multiple smaller transactions. To do
> > this, the existing attr operations must be modified to operate as either a
> > delayed operation or a inline operation since older filesystems will not be
> > able to use the new log entries.  This means that they cannot roll, commit, or
> > finish transactions.  Instead, they return -EAGAIN to allow the calling
> > function to handle the transaction. In this series, we focus on only the clean
> > up and refactoring needed to accomplish this. We will introduce delayed attrs
> > and parent pointers in a later set.
> > 
> > At the moment, I would like people to focus their review efforts on just this
> > "delay ready" subseries, as I think that is a more conservative use of peoples
> > review time.  I also think the set is a bit much to manage all at once, and we
> > need to get the infrastructure ironed out before we focus too much anything
> > that depends on it. But I do have the extended series for folks that want to
> > see the bigger picture of where this is going.
> > 
> > To help organize the set, I've arranged the patches to make sort of mini sets.
> > I thought it would help reviewers break down the reviewing some. For reviewing
> > purposes, the set could be broken up into 4 different phases:
> > 
> > Error code filtering (patches 1-2):
> > These two patches are all about finding and catching error codes that need to
> > be sent back up to user space before starting delayed operations.  Errors that
> > happen during a delayed operation are treated like internal errors that cause a
> > shutdown.  But we wouldnt want that for example: when the user tries to rename
> > a non existent attr.  So the idea is that we need to find all such conditions,
> > and take care of them before starting a delayed operation.
> >    xfs: Add xfs_has_attr and subroutines
> >    xfs: Check for -ENOATTR or -EEXIST
> > 
> > Move transactions upwards (patches 3-12): 
> > The goal of this subset is to try and move all the transaction specific code up
> > the call stack much as possible.  The idea being that once we get them to the
> > top, we can introduce the statemachine to handle the -EAGAIN logic where ever
> > the transactions used to be.
> >   xfs: Factor out new helper functions xfs_attr_rmtval_set
> >   xfs: Pull up trans handling in xfs_attr3_leaf_flipflags
> >   xfs: Split apart xfs_attr_leaf_addname
> >   xfs: Refactor xfs_attr_try_sf_addname
> >   xfs: Pull up trans roll from xfs_attr3_leaf_setflag
> >   xfs: Factor out xfs_attr_rmtval_invalidate
> >   xfs: Pull up trans roll in xfs_attr3_leaf_clearflag
> >   xfs: Refactor xfs_attr_rmtval_remove
> >   xfs: Pull up xfs_attr_rmtval_invalidate
> >   xfs: Add helper function xfs_attr_node_shrink
> > 
> > Modularizing and cleanups (patches 13-22):
> > Now that we have pulled the transactions up to where we need them, it's time to
> > start breaking down the top level functions into new subfunctions. The goal
> > being to work towards a top level function that deals mostly with the
> > statemachine, and helpers for those states
> >   xfs: Remove unneeded xfs_trans_roll_inode calls
> >   xfs: Remove xfs_trans_roll in xfs_attr_node_removename
> >   xfs: Add helpers xfs_attr_is_shortform and xfs_attr_set_shortform
> >   xfs: Add helper function xfs_attr_leaf_mark_incomplete
> >   xfs: Add remote block helper functions
> >   xfs: Add helper function xfs_attr_node_removename_setup
> >   xfs: Add helper function xfs_attr_node_removename_rmt
> >   xfs: Simplify xfs_attr_leaf_addname
> >   xfs: Simplify xfs_attr_node_addname
> >   xfs: Lift -ENOSPC handler from xfs_attr_leaf_addname
> 
> I'm happy to see everything up to here merged.

BTW, that translates as:

Acked-by: Dave Chinner <dchinner@redhat.com>

For the first 22 patches.

-Dave.
-- 
Dave Chinner
david@fromorbit.com