From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 887E533D6FC; Wed, 12 Nov 2025 14:58:16 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762959496; cv=none; b=IYOZA1m6aReuWFUbQLXMJbIxA0MMTMY+JCac4I0PVjyaoY1in6hjrIbQbhf7dtQLUxErmXThOe/UJ8qcwFw/SuIkq/XylysXPRM5cB+K3qOYIg+1xRpJqRhAc6ISoxIMI2MJp65MoHVNz6APBb12Gxbd9+CHmP5fvndwxdKf+Rk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762959496; c=relaxed/simple; bh=QmkuDvFTGlwKlCxWFFmHkzhOPjXSsTblL5h9yBKfpLA=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=saO0Y4iM2gL9snDpR7r9FxBK9S0NOjQSfB19qb8VlUlR4XlBqNtwMfdKexCFStuKVEC5W0WqvT2VD9JlRIuQ8OdHq80lLEygDqrUM1a25cvhfekyIHL9tump2X8Qk9G5q8fslxsKuyFZkD4JYhIIJbgklneJRQQGapdANpXNgNY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=HhtyOpnK; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="HhtyOpnK" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0D631C4CEF5; Wed, 12 Nov 2025 14:58:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1762959496; bh=QmkuDvFTGlwKlCxWFFmHkzhOPjXSsTblL5h9yBKfpLA=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=HhtyOpnK0brz95gMmr8l379+hE0zHC/jB7UhgRx/tP8ATtCkqCfVcUEcMd6wzC4TM pdcsVHfFYm7gEY+OsxswwP/Jy0ar5lEdoSiB1QHInCHHVhL25/fBUrtUwcZfMZFCJy bSElts+0OClYmSCF+6KVUiHIbxil2kesraPzw/V5I2+4CPgiCdKy0pmdLJPZYbcLrj UOhafJwvH7Q/pzO4S2xHX3LB7Q1mpMYEfyt+Sgib4Gh+vBeRH0x2tYD/YkO/10Rw5a By1vq11yLJPgguyLDLQTK5FkKuQZwC/aqdr599iYNyAvuilzwUefjHBZgiVSec06jn CvEVTRHh0YQOw== Message-ID: <3d30c6dea58836cbc4f3f0872260cdc9c586e8b4.camel@kernel.org> Subject: Re: [PATCH v5 07/14] VFS: introduce start_removing_dentry() From: Jeff Layton To: NeilBrown , Alexander Viro , Christian Brauner , Amir Goldstein Cc: Jan Kara , linux-fsdevel@vger.kernel.org, Chris Mason , David Sterba , David Howells , Greg Kroah-Hartman , "Rafael J. Wysocki" , Danilo Krummrich , Tyler Hicks , Miklos Szeredi , Chuck Lever , Olga Kornievskaia , Dai Ngo , Namjae Jeon , Steve French , Sergey Senozhatsky , Carlos Maiolino , John Johansen , Paul Moore , James Morris , "Serge E. Hallyn" , Stephen Smalley , Ondrej Mosnacek , Mateusz Guzik , Lorenzo Stoakes , Stefan Berger , "Darrick J. Wong" , linux-kernel@vger.kernel.org, netfs@lists.linux.dev, ecryptfs@vger.kernel.org, linux-nfs@vger.kernel.org, linux-unionfs@vger.kernel.org, linux-cifs@vger.kernel.org, linux-xfs@vger.kernel.org, linux-security-module@vger.kernel.org, selinux@vger.kernel.org Date: Wed, 12 Nov 2025 09:58:12 -0500 In-Reply-To: <20251106005333.956321-8-neilb@ownmail.net> References: <20251106005333.956321-1-neilb@ownmail.net> <20251106005333.956321-8-neilb@ownmail.net> Autocrypt: addr=jlayton@kernel.org; prefer-encrypt=mutual; keydata=mQINBE6V0TwBEADXhJg7s8wFDwBMEvn0qyhAnzFLTOCHooMZyx7XO7dAiIhDSi7G1NPxw n8jdFUQMCR/GlpozMFlSFiZXiObE7sef9rTtM68ukUyZM4pJ9l0KjQNgDJ6Fr342Htkjxu/kFV1Wv egyjnSsFt7EGoDjdKqr1TS9syJYFjagYtvWk/UfHlW09X+jOh4vYtfX7iYSx/NfqV3W1D7EDi0PqV T2h6v8i8YqsATFPwO4nuiTmL6I40ZofxVd+9wdRI4Db8yUNA4ZSP2nqLcLtFjClYRBoJvRWvsv4lm 0OX6MYPtv76hka8lW4mnRmZqqx3UtfHX/hF/zH24Gj7A6sYKYLCU3YrI2Ogiu7/ksKcl7goQjpvtV YrOOI5VGLHge0awt7bhMCTM9KAfPc+xL/ZxAMVWd3NCk5SamL2cE99UWgtvNOIYU8m6EjTLhsj8sn VluJH0/RcxEeFbnSaswVChNSGa7mXJrTR22lRL6ZPjdMgS2Km90haWPRc8Wolcz07Y2se0xpGVLEQ cDEsvv5IMmeMe1/qLZ6NaVkNuL3WOXvxaVT9USW1+/SGipO2IpKJjeDZfehlB/kpfF24+RrK+seQf CBYyUE8QJpvTZyfUHNYldXlrjO6n5MdOempLqWpfOmcGkwnyNRBR46g/jf8KnPRwXs509yAqDB6sE LZH+yWr9LQZEwARAQABtCVKZWZmIExheXRvbiA8amxheXRvbkBwb29jaGllcmVkcy5uZXQ+iQI7BB MBAgAlAhsDBgsJCAcDAgYVCAIJCgsEFgIDAQIeAQIXgAUCTpXWPAIZAQAKCRAADmhBGVaCFc65D/4 gBLNMHopQYgG/9RIM3kgFCCQV0pLv0hcg1cjr+bPI5f1PzJoOVi9s0wBDHwp8+vtHgYhM54yt43uI 7Htij0RHFL5eFqoVT4TSfAg2qlvNemJEOY0e4daljjmZM7UtmpGs9NN0r9r50W82eb5Kw5bc/r0km R/arUS2st+ecRsCnwAOj6HiURwIgfDMHGPtSkoPpu3DDp/cjcYUg3HaOJuTjtGHFH963B+f+hyQ2B rQZBBE76ErgTDJ2Db9Ey0kw7VEZ4I2nnVUY9B5dE2pJFVO5HJBMp30fUGKvwaKqYCU2iAKxdmJXRI ONb7dSde8LqZahuunPDMZyMA5+mkQl7kpIpR6kVDIiqmxzRuPeiMP7O2FCUlS2DnJnRVrHmCljLkZ Wf7ZUA22wJpepBligemtSRSbqCyZ3B48zJ8g5B8xLEntPo/NknSJaYRvfEQqGxgk5kkNWMIMDkfQO lDSXZvoxqU9wFH/9jTv1/6p8dHeGM0BsbBLMqQaqnWiVt5mG92E1zkOW69LnoozE6Le+12DsNW7Rj iR5K+27MObjXEYIW7FIvNN/TQ6U1EOsdxwB8o//Yfc3p2QqPr5uS93SDDan5ehH59BnHpguTc27Xi QQZ9EGiieCUx6Zh2ze3X2UW9YNzE15uKwkkuEIj60NvQRmEDfweYfOfPVOueC+iFifbQgSmVmZiBM YXl0b24gPGpsYXl0b25AcmVkaGF0LmNvbT6JAjgEEwECACIFAk6V0q0CGwMGCwkIBwMCBhUIAgkKC wQWAgMBAh4BAheAAAoJEAAOaEEZVoIViKUQALpvsacTMWWOd7SlPFzIYy2/fjvKlfB/Xs4YdNcf9q LqF+lk2RBUHdR/dGwZpvw/OLmnZ8TryDo2zXVJNWEEUFNc7wQpl3i78r6UU/GUY/RQmOgPhs3epQC 3PMJj4xFx+VuVcf/MXgDDdBUHaCTT793hyBeDbQuciARDJAW24Q1RCmjcwWIV/pgrlFa4lAXsmhoa c8UPc82Ijrs6ivlTweFf16VBc4nSLX5FB3ls7S5noRhm5/Zsd4PGPgIHgCZcPgkAnU1S/A/rSqf3F LpU+CbVBDvlVAnOq9gfNF+QiTlOHdZVIe4gEYAU3CUjbleywQqV02BKxPVM0C5/oVjMVx3bri75n1 TkBYGmqAXy9usCkHIsG5CBHmphv9MHmqMZQVsxvCzfnI5IO1+7MoloeeW/lxuyd0pU88dZsV/riHw 87i2GJUJtVlMl5IGBNFpqoNUoqmvRfEMeXhy/kUX4Xc03I1coZIgmwLmCSXwx9MaCPFzV/dOOrju2 xjO+2sYyB5BNtxRqUEyXglpujFZqJxxau7E0eXoYgoY9gtFGsspzFkVNntamVXEWVVgzJJr/EWW0y +jNd54MfPRqH+eCGuqlnNLktSAVz1MvVRY1dxUltSlDZT7P2bUoMorIPu8p7ZCg9dyX1+9T6Muc5d Hxf/BBP/ir+3e8JTFQBFOiLNdFtB9KZWZmIExheXRvbiA8amxheXRvbkBzYW1iYS5vcmc+iQI4BBM BAgAiBQJOldK9AhsDBgsJCAcDAgYVCAIJCgsEFgIDAQIeAQIXgAAKCRAADmhBGVaCFWgWD/0ZRi4h N9FK2BdQs9RwNnFZUr7JidAWfCrs37XrA/56olQl3ojn0fQtrP4DbTmCuh0SfMijB24psy1GnkPep naQ6VRf7Dxg/Y8muZELSOtsv2CKt3/02J1BBitrkkqmHyni5fLLYYg6fub0T/8Kwo1qGPdu1hx2BQ RERYtQ/S5d/T0cACdlzi6w8rs5f09hU9Tu4qV1JLKmBTgUWKN969HPRkxiojLQziHVyM/weR5Reu6 FZVNuVBGqBD+sfk/c98VJHjsQhYJijcsmgMb1NohAzwrBKcSGKOWJToGEO/1RkIN8tqGnYNp2G+aR 685D0chgTl1WzPRM6mFG1+n2b2RR95DxumKVpwBwdLPoCkI24JkeDJ7lXSe3uFWISstFGt0HL8Eew P8RuGC8s5h7Ct91HMNQTbjgA+Vi1foWUVXpEintAKgoywaIDlJfTZIl6Ew8ETN/7DLy8bXYgq0Xzh aKg3CnOUuGQV5/nl4OAX/3jocT5Cz/OtAiNYj5mLPeL5z2ZszjoCAH6caqsF2oLyAnLqRgDgR+wTQ T6gMhr2IRsl+cp8gPHBwQ4uZMb+X00c/Amm9VfviT+BI7B66cnC7Zv6Gvmtu2rEjWDGWPqUgccB7h dMKnKDthkA227/82tYoFiFMb/NwtgGrn5n2vwJyKN6SEoygGrNt0SI84y6hEVbQlSmVmZiBMYXl0b 24gPGpsYXl0b25AcHJpbWFyeWRhdGEuY29tPokCOQQTAQIAIwUCU4xmKQIbAwcLCQgHAwIBBhUIAg kKCwQWAgMBAh4BAheAAAoJEAAOaEEZVoIV1H0P/j4OUTwFd7BBbpoSp695qb6HqCzWMuExsp8nZjr uymMaeZbGr3OWMNEXRI1FWNHMtcMHWLP/RaDqCJil28proO+PQ/yPhsr2QqJcW4nr91tBrv/MqItu AXLYlsgXqp4BxLP67bzRJ1Bd2x0bWXurpEXY//VBOLnODqThGEcL7jouwjmnRh9FTKZfBDpFRaEfD FOXIfAkMKBa/c9TQwRpx2DPsl3eFWVCNuNGKeGsirLqCxUg5kWTxEorROppz9oU4HPicL6rRH22Ce 6nOAON2vHvhkUuO3GbffhrcsPD4DaYup4ic+DxWm+DaSSRJ+e1yJvwi6NmQ9P9UAuLG93S2MdNNbo sZ9P8k2mTOVKMc+GooI9Ve/vH8unwitwo7ORMVXhJeU6Q0X7zf3SjwDq2lBhn1DSuTsn2DbsNTiDv qrAaCvbsTsw+SZRwF85eG67eAwouYk+dnKmp1q57LDKMyzysij2oDKbcBlwB/TeX16p8+LxECv51a sjS9TInnipssssUDrHIvoTTXWcz7Y5wIngxDFwT8rPY3EggzLGfK5Zx2Q5S/N0FfmADmKknG/D8qG IcJE574D956tiUDKN4I+/g125ORR1v7bP+OIaayAvq17RP+qcAqkxc0x8iCYVCYDouDyNvWPGRhbL UO7mlBpjW9jK9e2fvZY9iw3QzIPGKtClKZWZmIExheXRvbiA8amVmZi5sYXl0b25AcHJpbWFyeWRh dGEuY29tPokCOQQTAQIAIwUCU4xmUAIbAwcLCQgHAwIBBhUIAgkKCwQWAgMBAh4BAheAAAoJEAAOa EEZVoIVzJoQALFCS6n/FHQS+hIzHIb56JbokhK0AFqoLVzLKzrnaeXhE5isWcVg0eoV2oTScIwUSU apy94if69tnUo4Q7YNt8/6yFM6hwZAxFjOXR0ciGE3Q+Z1zi49Ox51yjGMQGxlakV9ep4sV/d5a50 M+LFTmYSAFp6HY23JN9PkjVJC4PUv5DYRbOZ6Y1+TfXKBAewMVqtwT1Y+LPlfmI8dbbbuUX/kKZ5d dhV2736fgyfpslvJKYl0YifUOVy4D1G/oSycyHkJG78OvX4JKcf2kKzVvg7/Rnv+AueCfFQ6nGwPn 0P91I7TEOC4XfZ6a1K3uTp4fPPs1Wn75X7K8lzJP/p8lme40uqwAyBjk+IA5VGd+CVRiyJTpGZwA0 jwSYLyXboX+Dqm9pSYzmC9+/AE7lIgpWj+3iNisp1SWtHc4pdtQ5EU2SEz8yKvDbD0lNDbv4ljI7e flPsvN6vOrxz24mCliEco5DwhpaaSnzWnbAPXhQDWb/lUgs/JNk8dtwmvWnqCwRqElMLVisAbJmC0 BhZ/Ab4sph3EaiZfdXKhiQqSGdK4La3OTJOJYZphPdGgnkvDV9Pl1QZ0ijXQrVIy3zd6VCNaKYq7B AKidn5g/2Q8oio9Tf4XfdZ9dtwcB+bwDJFgvvDYaZ5bI3ln4V3EyW5i2NfXazz/GA/I/ZtbsigCFc 8ftCBKZWZmIExheXRvbiA8amxheXRvbkBrZXJuZWwub3JnPokCOAQTAQIAIgUCWe8u6AIbAwYLCQg HAwIGFQgCCQoLBBYCAwECHgECF4AACgkQAA5oQRlWghUuCg/+Lb/xGxZD2Q1oJVAE37uW308UpVSD 2tAMJUvFTdDbfe3zKlPDTuVsyNsALBGclPLagJ5ZTP+Vp2irAN9uwBuacBOTtmOdz4ZN2tdvNgozz uxp4CHBDVzAslUi2idy+xpsp47DWPxYFIRP3M8QG/aNW052LaPc0cedYxp8+9eiVUNpxF4SiU4i9J DfX/sn9XcfoVZIxMpCRE750zvJvcCUz9HojsrMQ1NFc7MFT1z3MOW2/RlzPcog7xvR5ENPH19ojRD CHqumUHRry+RF0lH00clzX/W8OrQJZtoBPXv9ahka/Vp7kEulcBJr1cH5Wz/WprhsIM7U9pse1f1g Yy9YbXtWctUz8uvDR7shsQxAhX3qO7DilMtuGo1v97I/Kx4gXQ52syh/w6EBny71CZrOgD6kJwPVV AaM1LRC28muq91WCFhs/nzHozpbzcheyGtMUI2Ao4K6mnY+3zIuXPygZMFr9KXE6fF7HzKxKuZMJO aEZCiDOq0anx6FmOzs5E6Jqdpo/mtI8beK+BE7Va6ni7YrQlnT0i3vaTVMTiCThbqsB20VrbMjlhp f8lfK1XVNbRq/R7GZ9zHESlsa35ha60yd/j3pu5hT2xyy8krV8vGhHvnJ1XRMJBAB/UYb6FyC7S+m QZIQXVeAA+smfTT0tDrisj1U5x6ZB9b3nBg65kc= Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.58.1 (3.58.1-1.fc43) Precedence: bulk X-Mailing-List: netfs@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 On Thu, 2025-11-06 at 11:50 +1100, NeilBrown wrote: > From: NeilBrown >=20 > start_removing_dentry() is similar to start_removing() but instead of > providing a name for lookup, the target dentry is given. >=20 > start_removing_dentry() checks that the dentry is still hashed and in > the parent, and if so it locks and increases the refcount so that > end_removing() can be used to finish the operation. >=20 > This is used in cachefiles, overlayfs, smb/server, and apparmor. >=20 > There will be other users including ecryptfs. >=20 > As start_removing_dentry() takes an extra reference to the dentry (to be > put by end_removing()), there is no need to explicitly take an extra > reference to stop d_delete() from using dentry_unlink_inode() to negate > the dentry - as in cachefiles_delete_object(), and ksmbd_vfs_unlink(). >=20 > cachefiles_bury_object() now gets an extra ref to the victim, which is > drops. As it includes the needed end_removing() calls, the caller > doesn't need them. >=20 > Reviewed-by: Amir Goldstein > Signed-off-by: NeilBrown >=20 > --- > Changes since v4 > Callers of cachefiles_bury_object() were incorrectly calling > end_removing() after that call. The dput() was needed, the unlock > wasn't. The dput() has been effectively moved into > cachefiles_bury_object() by removing a dget() which is now not needed. > --- > fs/cachefiles/interface.c | 11 +++++++---- > fs/cachefiles/namei.c | 30 ++++++++++++++---------------- > fs/cachefiles/volume.c | 9 ++++++--- > fs/namei.c | 33 +++++++++++++++++++++++++++++++++ > fs/overlayfs/dir.c | 10 ++++------ > fs/overlayfs/readdir.c | 8 ++++---- > fs/smb/server/vfs.c | 27 ++++----------------------- > include/linux/namei.h | 2 ++ > security/apparmor/apparmorfs.c | 8 ++++---- > 9 files changed, 78 insertions(+), 60 deletions(-) >=20 > diff --git a/fs/cachefiles/interface.c b/fs/cachefiles/interface.c > index 3e63cfe15874..a08250d244ea 100644 > --- a/fs/cachefiles/interface.c > +++ b/fs/cachefiles/interface.c > @@ -9,6 +9,7 @@ > #include > #include > #include > +#include > #include > #include > #include "internal.h" > @@ -428,11 +429,13 @@ static bool cachefiles_invalidate_cookie(struct fsc= ache_cookie *cookie) > if (!old_tmpfile) { > struct cachefiles_volume *volume =3D object->volume; > struct dentry *fan =3D volume->fanout[(u8)cookie->key_hash]; > + struct dentry *obj; > =20 > - inode_lock_nested(d_inode(fan), I_MUTEX_PARENT); > - cachefiles_bury_object(volume->cache, object, fan, > - old_file->f_path.dentry, > - FSCACHE_OBJECT_INVALIDATED); > + obj =3D start_removing_dentry(fan, old_file->f_path.dentry); > + if (!IS_ERR(obj)) > + cachefiles_bury_object(volume->cache, object, > + fan, obj, > + FSCACHE_OBJECT_INVALIDATED); > } > fput(old_file); > } > diff --git a/fs/cachefiles/namei.c b/fs/cachefiles/namei.c > index c7f0c6ab9b88..0104ac00485d 100644 > --- a/fs/cachefiles/namei.c > +++ b/fs/cachefiles/namei.c > @@ -261,6 +261,7 @@ static int cachefiles_unlink(struct cachefiles_cache = *cache, > * - Directory backed objects are stuffed into the graveyard for userspa= ce to > * delete > * On entry dir must be locked. It will be unlocked on exit. > + * On entry there must be at least 2 refs on rep, one will be dropped on= exit. > */ > int cachefiles_bury_object(struct cachefiles_cache *cache, > struct cachefiles_object *object, > @@ -275,12 +276,6 @@ int cachefiles_bury_object(struct cachefiles_cache *= cache, > =20 > _enter(",'%pd','%pd'", dir, rep); > =20 > - /* end_removing() will dput() @rep but we need to keep > - * a ref, so take one now. This also stops the dentry > - * being negated when unlinked which we need. > - */ > - dget(rep); > - > if (rep->d_parent !=3D dir) { > end_removing(rep); > _leave(" =3D -ESTALE"); > @@ -425,13 +420,12 @@ int cachefiles_delete_object(struct cachefiles_obje= ct *object, > =20 > _enter(",OBJ%x{%pD}", object->debug_id, object->file); > =20 > - /* Stop the dentry being negated if it's only pinned by a file struct. = */ > - dget(dentry); > - > - inode_lock_nested(d_backing_inode(fan), I_MUTEX_PARENT); > - ret =3D cachefiles_unlink(volume->cache, object, fan, dentry, why); > - inode_unlock(d_backing_inode(fan)); > - dput(dentry); > + dentry =3D start_removing_dentry(fan, dentry); > + if (IS_ERR(dentry)) > + ret =3D PTR_ERR(dentry); > + else > + ret =3D cachefiles_unlink(volume->cache, object, fan, dentry, why); > + end_removing(dentry); > return ret; > } > =20 > @@ -644,9 +638,13 @@ bool cachefiles_look_up_object(struct cachefiles_obj= ect *object) > =20 > if (!d_is_reg(dentry)) { > pr_err("%pd is not a file\n", dentry); > - inode_lock_nested(d_inode(fan), I_MUTEX_PARENT); > - ret =3D cachefiles_bury_object(volume->cache, object, fan, dentry, > - FSCACHE_OBJECT_IS_WEIRD); > + struct dentry *de =3D start_removing_dentry(fan, dentry); > + if (IS_ERR(de)) > + ret =3D PTR_ERR(de); > + else > + ret =3D cachefiles_bury_object(volume->cache, object, > + fan, de, > + FSCACHE_OBJECT_IS_WEIRD); > dput(dentry); > if (ret < 0) > return false; > diff --git a/fs/cachefiles/volume.c b/fs/cachefiles/volume.c > index 781aac4ef274..90ba926f488e 100644 > --- a/fs/cachefiles/volume.c > +++ b/fs/cachefiles/volume.c > @@ -7,6 +7,7 @@ > =20 > #include > #include > +#include > #include "internal.h" > #include > =20 > @@ -58,9 +59,11 @@ void cachefiles_acquire_volume(struct fscache_volume *= vcookie) > if (ret < 0) { > if (ret !=3D -ESTALE) > goto error_dir; > - inode_lock_nested(d_inode(cache->store), I_MUTEX_PARENT); > - cachefiles_bury_object(cache, NULL, cache->store, vdentry, > - FSCACHE_VOLUME_IS_WEIRD); > + vdentry =3D start_removing_dentry(cache->store, vdentry); > + if (!IS_ERR(vdentry)) > + cachefiles_bury_object(cache, NULL, cache->store, > + vdentry, > + FSCACHE_VOLUME_IS_WEIRD); > cachefiles_put_directory(volume->dentry); > cond_resched(); > goto retry; > diff --git a/fs/namei.c b/fs/namei.c > index da01b828ede6..729b42fb143b 100644 > --- a/fs/namei.c > +++ b/fs/namei.c > @@ -3323,6 +3323,39 @@ struct dentry *start_removing_noperm(struct dentry= *parent, > } > EXPORT_SYMBOL(start_removing_noperm); > =20 > +/** > + * start_removing_dentry - prepare to remove a given dentry > + * @parent: directory from which dentry should be removed > + * @child: the dentry to be removed > + * > + * A lock is taken to protect the dentry again other dirops and > + * the validity of the dentry is checked: correct parent and still hashe= d. > + * > + * If the dentry is valid and positive, a reference is taken and > + * returned. If not an error is returned. > + * > + * end_removing() should be called when removal is complete, or aborted. > + * > + * Returns: the valid dentry, or an error. > + */ > +struct dentry *start_removing_dentry(struct dentry *parent, > + struct dentry *child) > +{ > + inode_lock_nested(parent->d_inode, I_MUTEX_PARENT); > + if (unlikely(IS_DEADDIR(parent->d_inode) || > + child->d_parent !=3D parent || > + d_unhashed(child))) { > + inode_unlock(parent->d_inode); > + return ERR_PTR(-EINVAL); > + } > + if (d_is_negative(child)) { > + inode_unlock(parent->d_inode); > + return ERR_PTR(-ENOENT); > + } > + return dget(child); > +} > +EXPORT_SYMBOL(start_removing_dentry); > + > #ifdef CONFIG_UNIX98_PTYS > int path_pts(struct path *path) > { > diff --git a/fs/overlayfs/dir.c b/fs/overlayfs/dir.c > index 20682afdbd20..6d1d0e94e287 100644 > --- a/fs/overlayfs/dir.c > +++ b/fs/overlayfs/dir.c > @@ -47,14 +47,12 @@ static int ovl_cleanup_locked(struct ovl_fs *ofs, str= uct inode *wdir, > int ovl_cleanup(struct ovl_fs *ofs, struct dentry *workdir, > struct dentry *wdentry) > { > - int err; > - > - err =3D ovl_parent_lock(workdir, wdentry); > - if (err) > - return err; > + wdentry =3D start_removing_dentry(workdir, wdentry); > + if (IS_ERR(wdentry)) > + return PTR_ERR(wdentry); > =20 > ovl_cleanup_locked(ofs, workdir->d_inode, wdentry); > - ovl_parent_unlock(workdir); > + end_removing(wdentry); > =20 > return 0; > } > diff --git a/fs/overlayfs/readdir.c b/fs/overlayfs/readdir.c > index 1e9792cc557b..77ecc39fc33a 100644 > --- a/fs/overlayfs/readdir.c > +++ b/fs/overlayfs/readdir.c > @@ -1242,11 +1242,11 @@ int ovl_workdir_cleanup(struct ovl_fs *ofs, struc= t dentry *parent, > if (!d_is_dir(dentry) || level > 1) > return ovl_cleanup(ofs, parent, dentry); > =20 > - err =3D ovl_parent_lock(parent, dentry); > - if (err) > - return err; > + dentry =3D start_removing_dentry(parent, dentry); > + if (IS_ERR(dentry)) > + return PTR_ERR(dentry); > err =3D ovl_do_rmdir(ofs, parent->d_inode, dentry); > - ovl_parent_unlock(parent); > + end_removing(dentry); > if (err) { > struct path path =3D { .mnt =3D mnt, .dentry =3D dentry }; > =20 > diff --git a/fs/smb/server/vfs.c b/fs/smb/server/vfs.c > index 891ed2dc2b73..7c4ddc43ab39 100644 > --- a/fs/smb/server/vfs.c > +++ b/fs/smb/server/vfs.c > @@ -49,24 +49,6 @@ static void ksmbd_vfs_inherit_owner(struct ksmbd_work = *work, > i_uid_write(inode, i_uid_read(parent_inode)); > } > =20 > -/** > - * ksmbd_vfs_lock_parent() - lock parent dentry if it is stable > - * @parent: parent dentry > - * @child: child dentry > - * > - * Returns: %0 on success, %-ENOENT if the parent dentry is not stable > - */ > -int ksmbd_vfs_lock_parent(struct dentry *parent, struct dentry *child) > -{ > - inode_lock_nested(d_inode(parent), I_MUTEX_PARENT); > - if (child->d_parent !=3D parent) { > - inode_unlock(d_inode(parent)); > - return -ENOENT; > - } > - > - return 0; > -} > - > static int ksmbd_vfs_path_lookup(struct ksmbd_share_config *share_conf, > char *pathname, unsigned int flags, > struct path *path, bool do_lock) > @@ -1084,18 +1066,17 @@ int ksmbd_vfs_unlink(struct file *filp) > return err; > =20 > dir =3D dget_parent(dentry); > - err =3D ksmbd_vfs_lock_parent(dir, dentry); > - if (err) > + dentry =3D start_removing_dentry(dir, dentry); > + err =3D PTR_ERR(dentry); > + if (IS_ERR(dentry)) > goto out; > - dget(dentry); > =20 > if (S_ISDIR(d_inode(dentry)->i_mode)) > err =3D vfs_rmdir(idmap, d_inode(dir), dentry); > else > err =3D vfs_unlink(idmap, d_inode(dir), dentry, NULL); > =20 > - dput(dentry); > - inode_unlock(d_inode(dir)); > + end_removing(dentry); > if (err) > ksmbd_debug(VFS, "failed to delete, err %d\n", err); > out: I guess this answers my earlier question. > diff --git a/include/linux/namei.h b/include/linux/namei.h > index 0441f5921f87..d089e4e8fdd0 100644 > --- a/include/linux/namei.h > +++ b/include/linux/namei.h > @@ -95,6 +95,8 @@ struct dentry *start_removing(struct mnt_idmap *idmap, = struct dentry *parent, > struct qstr *name); > struct dentry *start_creating_noperm(struct dentry *parent, struct qstr = *name); > struct dentry *start_removing_noperm(struct dentry *parent, struct qstr = *name); > +struct dentry *start_removing_dentry(struct dentry *parent, > + struct dentry *child); > =20 > /** > * end_creating - finish action started with start_creating > diff --git a/security/apparmor/apparmorfs.c b/security/apparmor/apparmorf= s.c > index 391a586d0557..9d08d103f142 100644 > --- a/security/apparmor/apparmorfs.c > +++ b/security/apparmor/apparmorfs.c > @@ -355,17 +355,17 @@ static void aafs_remove(struct dentry *dentry) > if (!dentry || IS_ERR(dentry)) > return; > =20 > + /* ->d_parent is stable as rename is not supported */ > dir =3D d_inode(dentry->d_parent); > - inode_lock(dir); > - if (simple_positive(dentry)) { > + dentry =3D start_removing_dentry(dentry->d_parent, dentry); > + if (!IS_ERR(dentry) && simple_positive(dentry)) { > if (d_is_dir(dentry)) > simple_rmdir(dir, dentry); > else > simple_unlink(dir, dentry); > d_delete(dentry); > - dput(dentry); > } > - inode_unlock(dir); > + end_removing(dentry); > simple_release_fs(&aafs_mnt, &aafs_count); > } > =20 Reviewed-by: Jeff Layton