linux-kernel - Re: [PATCH 3/6] ceph: return the correct dentry on mkdir

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Message-ID: <64248546def6697c52169b5255da5745753eeab0.camel@kernel.org>
Date: Fri, 21 Feb 2025 08:31:14 -0500
From: Jeff Layton <jlayton@...nel.org>
To: NeilBrown <neilb@...e.de>, Alexander Viro <viro@...iv.linux.org.uk>, 
 Christian Brauner	 <brauner@...nel.org>, Jan Kara <jack@...e.cz>, Miklos
 Szeredi <miklos@...redi.hu>,  Xiubo Li <xiubli@...hat.com>, Ilya Dryomov
 <idryomov@...il.com>, Richard Weinberger <richard@....at>,  Anton Ivanov
 <anton.ivanov@...bridgegreys.com>, Johannes Berg
 <johannes@...solutions.net>, Trond Myklebust	 <trondmy@...nel.org>, Anna
 Schumaker <anna@...nel.org>, Chuck Lever	 <chuck.lever@...cle.com>, Olga
 Kornievskaia <okorniev@...hat.com>, Dai Ngo	 <Dai.Ngo@...cle.com>, Tom
 Talpey <tom@...pey.com>, Sergey Senozhatsky	 <senozhatsky@...omium.org>
Cc: linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org, 
	linux-cifs@...r.kernel.org, linux-nfs@...r.kernel.org, 
	linux-um@...ts.infradead.org, ceph-devel@...r.kernel.org,
 netfs@...ts.linux.dev
Subject: Re: [PATCH 3/6] ceph: return the correct dentry on mkdir

On Fri, 2025-02-21 at 10:36 +1100, NeilBrown wrote:
> ceph already splices the correct dentry (in splice_dentry()) from the
> result of mkdir but does nothing more with it.
> 
> Now that ->mkdir can return a dentry, return the correct dentry.
> 
> Signed-off-by: NeilBrown <neilb@...e.de>
> ---
>  fs/ceph/dir.c | 9 ++++++++-
>  1 file changed, 8 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/ceph/dir.c b/fs/ceph/dir.c
> index 39e0f240de06..c1a1c168bb27 100644
> --- a/fs/ceph/dir.c
> +++ b/fs/ceph/dir.c
> @@ -1099,6 +1099,7 @@ static struct dentry *ceph_mkdir(struct mnt_idmap *idmap, struct inode *dir,
>  	struct ceph_client *cl = mdsc->fsc->client;
>  	struct ceph_mds_request *req;
>  	struct ceph_acl_sec_ctx as_ctx = {};
> +	struct dentry *ret = NULL;
>  	int err;
>  	int op;
>  
> @@ -1166,14 +1167,20 @@ static struct dentry *ceph_mkdir(struct mnt_idmap *idmap, struct inode *dir,
>  	    !req->r_reply_info.head->is_dentry)
>  		err = ceph_handle_notrace_create(dir, dentry);
>  out_req:
> +	if (!err && req->r_dentry != dentry)
> +		/* Some other dentry was spliced in */
> +		ret = dget(req->r_dentry);
>  	ceph_mdsc_put_request(req);
>  out:
>  	if (!err)
> +		/* Should this use 'ret' ?? */

Probably? Is there a guarantee that "dentry" will even have an inode
attached if it got replaced by an disconnected one in the dcache?

>  		ceph_init_inode_acls(d_inode(dentry), &as_ctx);
>  	else
>  		d_drop(dentry);
>  	ceph_release_acl_sec_ctx(&as_ctx);
> -	return ERR_PTR(err);
> +	if (err)
> +		return ERR_PTR(err);
> +	return ret;
>  }
>  
>  static int ceph_link(struct dentry *old_dentry, struct inode *dir,

-- 
Jeff Layton <jlayton@...nel.org>