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Date: Mon, 5 May 2025 10:15:48 -0400
From: Steven Rostedt <rostedt@goodmis.org>
To: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org, linux-trace-kernel@vger.kernel.org,
 Christian Brauner <brauner@kernel.org>, Jan Kara <jack@suse.cz>
Subject: Re: [PATCH][RFC][CFT] kill vfs_submount(), already
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On Sat, 3 May 2025 22:29:25 +0100
Al Viro <viro@zeniv.linux.org.uk> wrote:

> @@ -10081,10 +10084,20 @@ static struct vfsmount *trace_automount(struct dentry *mntpt, void *ingore)
>  	type = get_fs_type("tracefs");
>  	if (!type)
>  		return NULL;
> -	mnt = vfs_submount(mntpt, type, "tracefs", NULL);
> +
> +	fc = fs_context_for_submount(type, mntpt);
> +	if (IS_ERR(fc))
> +		return ERR_CAST(fc);

As Jan mentioned, the put_filesystem(type) is need in the error path.

> +
> +	ret = vfs_parse_fs_string(fc, "source",
> +				  "tracefs", strlen("tracefs"));
> +	if (!ret)
> +		mnt = fc_mount(fc);
> +	else
> +		mnt = ERR_PTR(ret);
> +
> +	put_fs_context(fc);
>  	put_filesystem(type);
> -	if (IS_ERR(mnt))
> -		return NULL;

This didn't apply cleanly to Linus's tree, nor linux-next, due to missing:

	mntget(mnt);

Was that supposed to be deleted too?

Anyway, I applied this (still keeping the mntget()) and it appears to work.

-- Steve


>  	return mnt;
>  }