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 7911B634 for ; Wed, 26 Feb 2025 12:46:32 +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=1740573992; cv=none; b=l5tvZwXMW3qUY1maXWZOtqZoOVvVXalyRqhHSO6sAh8sPfgGyT5bDZagbtCEweGbJI5EHCBQhRQpEbWTfCx9G4iUOB3wOcRpEJJ3WQ+SCa5mMNGd5FBfLaQ4snsA+PQKLPuVY3mckSFsYavcq++lKRXR1rVUfiNljhPGoFXl42g= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740573992; c=relaxed/simple; bh=qLd3g7ys5LnidPeIEKMfnB99gYuHtsR6RAastAruVXM=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=Hgbp6YQclyWCzHnKwQws3FLqQOyUp7ug8DzoGN8UfVJZSsAtEGKhxnX7eQmL0SSVWi6CZ5ezIXfpp8tafy+qS6eaV2r+qIulUBHAWu7AIxC90A4J4cHunOePGYgmn6k0ezkd1g32EKIWevQC0fVtiBqgka/B+lF+qc3zlOXVFMY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=RzbX4zXK; 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="RzbX4zXK" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 59B52C4CED6; Wed, 26 Feb 2025 12:46:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1740573992; bh=qLd3g7ys5LnidPeIEKMfnB99gYuHtsR6RAastAruVXM=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=RzbX4zXKTouecvuVG0bhvK3zP8fZ0jc0SGqLhI7+TRL15cSZz83I0TAbfzaQfGtSR Eu9c0ElJ2WmDcAtpk4DODrG9j492w4tRsOvxS3IJvLqxvKgl0bNDWGXDs1sgbe6i+I eFvJjhPMaSPTrzl3RCyKqET/OK8xtHesZkgYV57RFkqBa2xQjY0cQstY/bs6schcVN yPV/DCRgq6vNV0ga6v+N1dKJaKg3UeQ6Y7BQKQN9sbLqn2rAZIDLWDCZWsypBNUSt5 KyTqvaZX3GA7cPcu9Q1c5mfJf/0KtHN5FLWWgBqnxE3AcMgbb2MyIWghS0uN+Ti+e4 bH2ZbTjXJWeYg== Message-ID: Subject: Re: [PATCH 1/2] nfs/vfs: discard d_exact_alias() From: Jeff Layton To: NeilBrown , Alexander Viro , Christian Brauner Cc: Chuck Lever , Trond Myklebust , Anna Schumaker , linux-nfs@vger.kernel.org Date: Wed, 26 Feb 2025 07:46:29 -0500 In-Reply-To: <20250226062135.2043651-2-neilb@suse.de> References: <20250226062135.2043651-1-neilb@suse.de> <20250226062135.2043651-2-neilb@suse.de> Autocrypt: addr=jlayton@kernel.org; prefer-encrypt=mutual; keydata=mQINBE6V0TwBEADXhJg7s8wFDwBMEvn0qyhAnzFLTOCHooMZyx7XO7dAiIhDSi7G1NPxw n8jdFUQMCR/GlpozMFlSFiZXiObE7sef9rTtM68ukUyZM4pJ9l0KjQNgDJ6Fr342Htkjxu/kFV1Wv egyjnSsFt7EGoDjdKqr1TS9syJYFjagYtvWk/UfHlW09X+jOh4vYtfX7iYSx/NfqV3W1D7EDi0PqV T2h6v8i8YqsATFPwO4nuiTmL6I40ZofxVd+9wdRI4Db8yUNA4ZSP2nqLcLtFjClYRBoJvRWvsv4lm 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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 3.54.3 (3.54.3-1.fc41) Precedence: bulk X-Mailing-List: linux-nfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 On Wed, 2025-02-26 at 17:18 +1100, NeilBrown wrote: > d_exact_alias() is a descendent of d_add_unique() which was introduced > 20 years ago mostly likely to work around problems with NFS servers of > the time. It is now not used in several situations were it was > originally needed and there have been no reports of problems - > presumably the old NFS servers have been improved. This only place it > is now use is in NFSv4 code and the old problematic servers are thought > to have been v2/v3 only. >=20 > There is no clear benefit in reusing a unhashed() dentry which happens > to have the same name as the dentry we are adding. >=20 > So this patch removes d_exact_alias() and the one place that it is used. >=20 > Cc: Trond Myklebust > Signed-off-by: NeilBrown > --- > fs/dcache.c | 46 ------------------------------------------ > fs/nfs/nfs4proc.c | 4 +--- > include/linux/dcache.h | 1 - > 3 files changed, 1 insertion(+), 50 deletions(-) >=20 > diff --git a/fs/dcache.c b/fs/dcache.c > index e3634916ffb9..726a5be2747b 100644 > --- a/fs/dcache.c > +++ b/fs/dcache.c > @@ -2687,52 +2687,6 @@ void d_add(struct dentry *entry, struct inode *ino= de) > } > EXPORT_SYMBOL(d_add); > =20 > -/** > - * d_exact_alias - find and hash an exact unhashed alias > - * @entry: dentry to add > - * @inode: The inode to go with this dentry > - * > - * If an unhashed dentry with the same name/parent and desired > - * inode already exists, hash and return it. Otherwise, return > - * NULL. > - * > - * Parent directory should be locked. > - */ > -struct dentry *d_exact_alias(struct dentry *entry, struct inode *inode) > -{ > - struct dentry *alias; > - unsigned int hash =3D entry->d_name.hash; > - > - spin_lock(&inode->i_lock); > - hlist_for_each_entry(alias, &inode->i_dentry, d_u.d_alias) { > - /* > - * Don't need alias->d_lock here, because aliases with > - * d_parent =3D=3D entry->d_parent are not subject to name or > - * parent changes, because the parent inode i_mutex is held. > - */ > - if (alias->d_name.hash !=3D hash) > - continue; > - if (alias->d_parent !=3D entry->d_parent) > - continue; > - if (!d_same_name(alias, entry->d_parent, &entry->d_name)) > - continue; > - spin_lock(&alias->d_lock); > - if (!d_unhashed(alias)) { > - spin_unlock(&alias->d_lock); > - alias =3D NULL; > - } else { > - dget_dlock(alias); > - __d_rehash(alias); > - spin_unlock(&alias->d_lock); > - } > - spin_unlock(&inode->i_lock); > - return alias; > - } > - spin_unlock(&inode->i_lock); > - return NULL; > -} > -EXPORT_SYMBOL(d_exact_alias); > - > static void swap_names(struct dentry *dentry, struct dentry *target) > { > if (unlikely(dname_external(target))) { > diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c > index df9669d4ded7..0a46b193f18e 100644 > --- a/fs/nfs/nfs4proc.c > +++ b/fs/nfs/nfs4proc.c > @@ -3153,9 +3153,7 @@ static int _nfs4_open_and_get_state(struct nfs4_ope= ndata *opendata, > if (d_really_is_negative(dentry)) { > struct dentry *alias; > d_drop(dentry); > - alias =3D d_exact_alias(dentry, state->inode); > - if (!alias) > - alias =3D d_splice_alias(igrab(state->inode), dentry); > + alias =3D d_splice_alias(igrab(state->inode), dentry); > /* d_splice_alias() can't fail here - it's a non-directory */ > if (alias) { > dput(ctx->dentry); > diff --git a/include/linux/dcache.h b/include/linux/dcache.h > index 4afb60365675..8a63978187a4 100644 > --- a/include/linux/dcache.h > +++ b/include/linux/dcache.h > @@ -253,7 +253,6 @@ extern struct dentry * d_splice_alias(struct inode *,= struct dentry *); > extern struct dentry * d_add_ci(struct dentry *, struct inode *, struct = qstr *); > extern bool d_same_name(const struct dentry *dentry, const struct dentry= *parent, > const struct qstr *name); > -extern struct dentry * d_exact_alias(struct dentry *, struct inode *); > extern struct dentry *d_find_any_alias(struct inode *inode); > extern struct dentry * d_obtain_alias(struct inode *); > extern struct dentry * d_obtain_root(struct inode *); Reviewed-by: Jeff Layton