[PATCH v4 0/7]] VFS: Prepare to lift lookup out of exclusive lock for directory ops

[NeilBrown]

Following are 7 VFS patches which modify or introduce APIs that will
allow modifying filesystems so that they will work with a proposed
change to move d_alloc_paralle() out from the parent i_rw_sem lock.

If these can land in a non-rebasing tree, I can work with individual
filesystem maintainers to start using these APIs.

I haven't included d_alloc_noblock_return() as it is only needed for one
fs (ovl) and it is not yet clear that it is the best approach.

I also haven't included the change to d_alloc_name() as that is only
needed so that I can deprecate d_alloc() and there is no rush for that.

Patch 2/7 is exactly the patch Al proposed in the conversation for v3.
I have taken the libery of adding a Signed-off-by from Al to match the
Co-developed-by.  I hope that was not inappropriate.

I have been testing this series over NFS mounts from XFS so patches 2
and 3 don't seem to be causing any problems.  The changes in 4/5/6/7
won't be tested by this, and some cannot be tested until filesystems
start using new interfaces.

Thanks,
NeilBrown


 [PATCH v4 1/7] VFS: fix various typos in documentation for
 [PATCH v4 2/7] VFS: use wait_var_event for waiting in
 [PATCH v4 3/7] VFS: enhance d_splice_alias() to handle in-lookup
 [PATCH v4 4/7] VFS: introduce d_alloc_noblock()
 [PATCH v4 5/7] VFS: add d_duplicate()
 [PATCH v4 6/7] VFS: Add LOOKUP_SHARED flag.
 [PATCH v4 7/7] VFS/xfs/ntfs: drop parent lock across