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Date: Fri, 14 Feb 2025 06:13:55 +0000
From: Al Viro <viro@zeniv.linux.org.uk>
To: NeilBrown <neilb@suse.de>
Cc: Christian Brauner <brauner@kernel.org>,
	Trond Myklebust <trondmy@kernel.org>,
	Anna Schumaker <anna@kernel.org>, linux-nfs@vger.kernel.org,
	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 0/3} Change ->mkdir() and vfs_mkdir() to return a dentry
Message-ID: <20250214061355.GC1977892@ZenIV>
References: <20250214052204.3105610-1-neilb@suse.de>
 <20250214060039.GB1977892@ZenIV>
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Sender: Al Viro <viro@ftp.linux.org.uk>

On Fri, Feb 14, 2025 at 06:00:39AM +0000, Al Viro wrote:

> 3) I'm pretty sure that NFS is *not* the only filesystem that returns
> unhashed negative in some success cases; will need to go over the instances
> to verify that, though.

Definitely so: in cifs_mkdir() we have
        if ((server->ops->posix_mkdir) && (tcon->posix_extensions)) {
                rc = server->ops->posix_mkdir(xid, inode, mode, tcon, full_path,
                                              cifs_sb);
                d_drop(direntry); /* for time being always refresh inode info */
                goto mkdir_out;
        }
There might be other cases.  hostfs is definitely like that, I'm pretty
sure that kernfs is as well...