Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Date:   Tue, 27 Jun 2023 01:09:00 +0200
From:   Ahelenia =?utf-8?Q?Ziemia=C5=84ska?= 
        <nabijaczleweli@nabijaczleweli.xyz>
To:     Amir Goldstein <amir73il@gmail.com>
Cc:     Alexander Viro <viro@zeniv.linux.org.uk>,
        Christian Brauner <brauner@kernel.org>,
        linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
        Jan Kara <jack@suse.cz>,
        Chung-Chiang Cheng <cccheng@synology.com>
Subject: [PATCH v2 1/3] splice: always fsnotify_access(in),
 fsnotify_modify(out) on success
Message-ID: <al4pxc2uftonry5vyunx5qblllbaakjsehrc74fbbk7pxddyv7@gn3k55eldmmp>
References: <CAOQ4uxj_DLm8_stRJPR7i8bp9aJ5VtjzWqHL2egCTKe3M-6KSw@mail.gmail.com>
MIME-Version: 1.0
Content-Type: multipart/signed; micalg=pgp-sha512;
        protocol="application/pgp-signature"; boundary="gryd5vox5utp35lw"
Content-Disposition: inline
In-Reply-To: <CAOQ4uxj_DLm8_stRJPR7i8bp9aJ5VtjzWqHL2egCTKe3M-6KSw@mail.gmail.com>
User-Agent: NeoMutt/20230517
Precedence: bulk


--gryd5vox5utp35lw
Content-Type: text/plain; charset=utf-8
Content-Disposition: inline
Content-Transfer-Encoding: quoted-printable

The current behaviour caused an asymmetry where some write APIs
(write, sendfile) would notify the written-to/read-from objects,
but splice wouldn't.

This affected userspace which used inotify, like coreutils tail -f.

Fixes: 983652c69199 ("splice: report related fsnotify events")
Link: https://lore.kernel.org/linux-fsdevel/jbyihkyk5dtaohdwjyivambb2gffyjs=
3dodpofafnkkunxq7bu@jngkdxx65pux/t/#u
Signed-off-by: Ahelenia Ziemia=C5=84ska <nabijaczleweli@nabijaczleweli.xyz>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
---
No changes since v1 (except in the message).

 fs/splice.c | 21 ++++++++++++---------
 1 file changed, 12 insertions(+), 9 deletions(-)

diff --git a/fs/splice.c b/fs/splice.c
index 3e06611d19ae..94fae24f9d54 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -1154,7 +1154,8 @@ long do_splice(struct file *in, loff_t *off_in, struc=
t file *out,
 		if ((in->f_flags | out->f_flags) & O_NONBLOCK)
 			flags |=3D SPLICE_F_NONBLOCK;
=20
-		return splice_pipe_to_pipe(ipipe, opipe, len, flags);
+		ret =3D splice_pipe_to_pipe(ipipe, opipe, len, flags);
+		goto notify;
 	}
=20
 	if (ipipe) {
@@ -1182,15 +1183,12 @@ long do_splice(struct file *in, loff_t *off_in, str=
uct file *out,
 		ret =3D do_splice_from(ipipe, out, &offset, len, flags);
 		file_end_write(out);
=20
-		if (ret > 0)
-			fsnotify_modify(out);
-
 		if (!off_out)
 			out->f_pos =3D offset;
 		else
 			*off_out =3D offset;
=20
-		return ret;
+		goto notify;
 	}
=20
 	if (opipe) {
@@ -1209,18 +1207,23 @@ long do_splice(struct file *in, loff_t *off_in, str=
uct file *out,
=20
 		ret =3D splice_file_to_pipe(in, opipe, &offset, len, flags);
=20
-		if (ret > 0)
-			fsnotify_access(in);
-
 		if (!off_in)
 			in->f_pos =3D offset;
 		else
 			*off_in =3D offset;
=20
-		return ret;
+		goto notify;
 	}
=20
 	return -EINVAL;
+
+notify:
+	if (ret > 0) {
+		fsnotify_access(in);
+		fsnotify_modify(out);
+	}
+
+	return ret;
 }
=20
 static long __do_splice(struct file *in, loff_t __user *off_in,
--=20
2.39.2


--gryd5vox5utp35lw
Content-Type: application/pgp-signature; name="signature.asc"

-----BEGIN PGP SIGNATURE-----
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=12tM
-----END PGP SIGNATURE-----

--gryd5vox5utp35lw--