Re: [PATCH/RFC 00/18] VFS/nfsd: replace dentry_create()

On 2026-06-01 16:37 +1000, NeilBrown wrote:
> My recent proposal for inverting the order between inode_lock() on a
> parent dir and d_alloc_parallel()[1] missed that fact that atomic_open()
> has two callers, and would have resulted in easy deadlocks from nfsd
> when re-exporting and NFS filesystem.
> 
> I think the best way to fix this is to provide a richer interface for
> nfsd to use, which includes all the locking as well as inode_operations
> calls.  This allows the nfsd behaviour to share more code with the
> system-call behaviour.
> 
> This series refactors code between lookup_open() and
> open_last_lookups(), and uses the new lookup_open() to provide
> vfs_lookup_open().  It then rearranges the code in nfsd so that it can
> easily use vfs_lookup_open() instead of dentry_create().  Finally
> dentry_create() is removed.
> 
> This series is based on a merge of nfsd-testing, vfs-next/work.dcache,
> and vfs/vfs.fixes (though I can't see my "Fix possible failure to
> unlock.."[2] patch in there yet).  So I probably will need to resubmit
> after a bunch of that has hit mainline - though a few of the patches

Yes, please resubmit. 

> This will conflict with the O_CREAT|O_DIRECTORY work so obviously we'll need to
> work out how to order them once we both have enough positive review.

I have that on my todo but somehow said todo keeps growing...