Re: [PATCH 0/4] Prepare for fsnotify pre-content permission events

From: Josef Bacik <josef@toxicpanda.com>
To: Amir Goldstein <amir73il@gmail.com>
Cc: Christian Brauner <brauner@kernel.org>, Jan Kara <jack@suse.cz>,
	Jeff Layton <jlayton@kernel.org>, Christoph Hellwig <hch@lst.de>,
	David Howells <dhowells@redhat.com>, Jens Axboe <axboe@kernel.dk>,
	Miklos Szeredi <miklos@szeredi.hu>,
	Al Viro <viro@zeniv.linux.org.uk>,
	linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH 0/4] Prepare for fsnotify pre-content permission events
Date: Thu, 7 Dec 2023 13:51:05 -0800	[thread overview]
Message-ID: <20231207215105.GA94859@localhost.localdomain> (raw)
In-Reply-To: <20231207123825.4011620-1-amir73il@gmail.com>

On Thu, Dec 07, 2023 at 02:38:21PM +0200, Amir Goldstein wrote:
> Hi Jan & Christian,
> 
> I am not planning to post the fanotify pre-content event patches [1]
> for 6.8.  Not because they are not ready, but because the usersapce
> example is not ready.
> 
> Also, I think it is a good idea to let the large permission hooks
> cleanup work to mature over the 6.8 cycle, before we introduce the
> pre-content events.
> 
> However, I would like to include the following vfs prep patches along
> with the vfs.rw PR for 6.8, which could be titled as the subject of
> this cover letter.
> 
> Patch 1 is a variant of a cleanup suggested by Christoph to get rid
> of the generic_copy_file_range() exported symbol.
> 
> Patches 2,3 add the file_write_not_started() assertion to fsnotify
> file permission hooks.  IMO, it is important to merge it along with
> vfs.rw because:
> 
> 1. This assert is how I tested vfs.rw does what it aimed to achieve
> 2. This will protect us from new callers that break the new order
> 3. The commit message of patch 3 provides the context for the entire
>    series and can be included in the PR message
> 
> Patch 4 is the final change of fsnotify permission hook locations/args
> and is the last of the vfs prerequsites for pre-content events.
> 
> If we merge patch 4 for 6.8, it will be much easier for the development
> of fanotify pre-content events in 6.9 dev cycle, which be contained
> within the fsnotify subsystem.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>

Can you get an fstest added that exercises the freeze deadlock?  I feel like
we're going to break that at some point and I'd rather find out in testing than
in production.  Thanks,

Josef