From patchwork Wed Feb 21 17:14:05 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Gabriel Krisman Bertazi X-Patchwork-Id: 13565995 Received: from smtp-out1.suse.de (smtp-out1.suse.de [195.135.223.130]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 717DA33F7; Wed, 21 Feb 2024 17:14:29 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=195.135.223.130 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708535671; cv=none; b=uxEcRyIOdXuVnxxoJlz6qFcPmXBeh6gN0BA4t+ClsTcbDddtxpp59ezR5tU+XedVLXEiCmSNteJzstRc7DOnd13sEgnMgWNeQaiIyic/w19WjwmG2/L92ovI6G76OxeG7RprW02Dnt8a/F8jsKOOIlv/hfcEeP8Sc4Gf0ahlIxs= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708535671; c=relaxed/simple; bh=GWOcriDZ6/RCSRNtgUKVCdc752tbsc4zjdsjTuhCaU0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=PAs+Pw1E+UP7c8yOwNji49lFKlLsFl78CH8ctD8hs10H84aq/uzz01D0zUlpB4+USZNl3I+8tRDpjESj6JBEalIVc13hz7uDiAwuVIJAdv4lsUkGo6JqB+LoqcoLF4n0jHhpSkeEy8herNvrcN8xRCpKx8609Ip+LYOhoK1t344= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=suse.de; spf=pass smtp.mailfrom=suse.de; arc=none smtp.client-ip=195.135.223.130 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=suse.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=suse.de Received: from imap1.dmz-prg2.suse.org (imap1.dmz-prg2.suse.org [IPv6:2a07:de40:b281:104:10:150:64:97]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id C516821DB0; Wed, 21 Feb 2024 17:14:27 +0000 (UTC) Received: from imap1.dmz-prg2.suse.org (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by imap1.dmz-prg2.suse.org (Postfix) with ESMTPS id 89599139D0; Wed, 21 Feb 2024 17:14:27 +0000 (UTC) Received: from dovecot-director2.suse.de ([2a07:de40:b281:106:10:150:64:167]) by imap1.dmz-prg2.suse.org with ESMTPSA id 2S5XG3Mv1mVYKgAAD6G6ig (envelope-from ); Wed, 21 Feb 2024 17:14:27 +0000 From: Gabriel Krisman Bertazi To: ebiggers@kernel.org, viro@zeniv.linux.org.uk, jaegeuk@kernel.org Cc: tytso@mit.edu, amir73il@gmail.com, linux-ext4@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, linux-fsdevel@vger.kernel.org, brauner@kernel.org, Gabriel Krisman Bertazi Subject: [PATCH v7 03/10] fscrypt: Drop d_revalidate for valid dentries during lookup Date: Wed, 21 Feb 2024 12:14:05 -0500 Message-ID: <20240221171412.10710-4-krisman@suse.de> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240221171412.10710-1-krisman@suse.de> References: <20240221171412.10710-1-krisman@suse.de> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Authentication-Results: smtp-out1.suse.de; none X-Spamd-Result: default: False [-4.00 / 50.00]; REPLY(-4.00)[] X-Rspamd-Server: rspamd1.dmz-prg2.suse.org X-Rspamd-Queue-Id: C516821DB0 X-Spam-Level: X-Spam-Score: -4.00 X-Spam-Flag: NO Unencrypted and encrypted-dentries where the key is available don't need to be revalidated by fscrypt, since they don't go stale from under VFS and the key cannot be removed for the encrypted case without evicting the dentry. Disable their d_revalidate hook on the first lookup, to avoid repeated revalidation later. This is done in preparation to always configuring d_op through sb->s_d_op. The only part detail is that, since the filesystem might have other features that require revalidation, we only apply this optimization if the d_revalidate handler is fscrypt_d_revalidate itself. Finally, we need to clean the dentry->flags even for unencrypted dentries, so the ->d_lock might be acquired even for them. In order to avoid doing it for filesystems that don't care about fscrypt at all, we peek ->d_flags without the lock at first, and only acquire it if we actually need to write the flag. Signed-off-by: Gabriel Krisman Bertazi --- changes since v5 - d_set_always_valid -> d_revalidate (eric) - Avoid acquiring the lock for !fscrypt-capable filesystems (eric, Christian) --- include/linux/fscrypt.h | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) diff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h index c76f859cf019..78af02b35bd9 100644 --- a/include/linux/fscrypt.h +++ b/include/linux/fscrypt.h @@ -264,10 +264,29 @@ static inline bool fscrypt_is_nokey_name(const struct dentry *dentry) static inline void fscrypt_prepare_dentry(struct dentry *dentry, bool is_nokey_name) { + /* + * This code tries to only take ->d_lock when necessary to write + * to ->d_flags. We shouldn't be peeking on d_flags for + * DCACHE_OP_REVALIDATE unlocked, but in the unlikely case + * there is a race, the worst it can happen is that we fail to + * unset DCACHE_OP_REVALIDATE and pay the cost of an extra + * d_revalidate. + */ if (is_nokey_name) { spin_lock(&dentry->d_lock); dentry->d_flags |= DCACHE_NOKEY_NAME; spin_unlock(&dentry->d_lock); + } else if (dentry->d_flags & DCACHE_OP_REVALIDATE && + dentry->d_op->d_revalidate == fscrypt_d_revalidate) { + /* + * Unencrypted dentries and encrypted dentries where the + * key is available are always valid from fscrypt + * perspective. Avoid the cost of calling + * fscrypt_d_revalidate unnecessarily. + */ + spin_lock(&dentry->d_lock); + dentry->d_flags &= ~DCACHE_OP_REVALIDATE; + spin_unlock(&dentry->d_lock); } } @@ -997,6 +1016,9 @@ static inline int fscrypt_prepare_lookup(struct inode *dir, fname->usr_fname = &dentry->d_name; fname->disk_name.name = (unsigned char *)dentry->d_name.name; fname->disk_name.len = dentry->d_name.len; + + fscrypt_prepare_dentry(dentry, false); + return 0; }