From nobody Mon Feb 9 10:26:14 2026 Received: from madrid.collaboradmins.com (madrid.collaboradmins.com [46.235.227.194]) (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 D3E0713398E; Tue, 2 Apr 2024 15:48:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=46.235.227.194 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712072935; cv=none; b=sNFMLsxtwfxtSfeXFRWIl2OdekPxjYzsX3LklEBknQhgMWlNvE45u26yLcGdPFITyrlqWXNacS8DJzWNwp+3m+icGgLKRSfQkoEz+SIPBYsPXOE70snRL+EaYWJJmhqDLAGx96Les5fRyMCwtQpGy4Qe+RG05WDzsw9BO9Apm/A= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712072935; c=relaxed/simple; bh=upTn9VDPH4ATj696dO2v0HAAxcgXeQncdfgIxpTDi8A=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=uyIihCfurzQ8OGva5tarVQvSr/+CjZ2h5gEJUn8IFoxhnqBd69UVeBiQAFvipiDgWuEPviW57jdNHsf+NdI1ZTqVp7pj0yty7YQ05OT+ylwR+m1vL/rYoZfXXjyOCdq20GyKpvYKW6Dm0UFP6XDLKG76W4DQTCi4GEoDq8Rcgpc= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=collabora.com; spf=pass smtp.mailfrom=collabora.com; dkim=pass (2048-bit key) header.d=collabora.com header.i=@collabora.com header.b=At6Y/fkM; arc=none smtp.client-ip=46.235.227.194 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=collabora.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=collabora.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=collabora.com header.i=@collabora.com header.b="At6Y/fkM" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1712072932; bh=upTn9VDPH4ATj696dO2v0HAAxcgXeQncdfgIxpTDi8A=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=At6Y/fkMPPh7NBpLbP7gT7+bSmI28T5D4dzO8VJBNOUGsTZxktpxHDM98g3MntF5f m5TOqJ7gc2i8eYm3AS6qmhk91epofuEbKzju3tj13nCgvP69GYQSAFakBgK0oKJwhd 8XRIua8emh7dh/OTIlgILTmd8tyaUDWlHino9Ipv4INIlCMUX+dXHCQEVFchljezWu t7WJLydJDV8jGMfUtSuvydhIL98xzzLljwXCE1WtqBioT0286Se3zouSW7W2fAH5sI o3eDK/bzu52uaZeeng7ZbS4gkS3Z6VGhMa8++2N+RYibxf4OHvab8CeXR35T7mL760 vv/fCpUeQa/4Q== Received: from eugen-station.. (cola.collaboradmins.com [195.201.22.229]) (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) (Authenticated sender: ehristev) by madrid.collaboradmins.com (Postfix) with ESMTPSA id 30CD037820EF; Tue, 2 Apr 2024 15:48:51 +0000 (UTC) From: Eugen Hristev To: tytso@mit.edu, adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org, jaegeuk@kernel.org, chao@kernel.org, linux-f2fs-devel@lists.sourceforge.net, linux-fsdevel@vger.kernel.org Cc: linux-kernel@vger.kernel.org, kernel@collabora.com, eugen.hristev@collabora.com, viro@zeniv.linux.org.uk, brauner@kernel.org, jack@suse.cz, krisman@suse.de, Gabriel Krisman Bertazi Subject: [PATCH v15 3/9] libfs: Introduce case-insensitive string comparison helper Date: Tue, 2 Apr 2024 18:48:36 +0300 Message-Id: <20240402154842.508032-4-eugen.hristev@collabora.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20240402154842.508032-1-eugen.hristev@collabora.com> References: <20240402154842.508032-1-eugen.hristev@collabora.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Gabriel Krisman Bertazi generic_ci_match can be used by case-insensitive filesystems to compare strings under lookup with dirents in a case-insensitive way. This function is currently reimplemented by each filesystem supporting casefolding, so this reduces code duplication in filesystem-specific code. Signed-off-by: Gabriel Krisman Bertazi [eugen.hristev@collabora.com: rework to first test the exact match] Signed-off-by: Eugen Hristev --- fs/libfs.c | 77 ++++++++++++++++++++++++++++++++++++++++++++++ include/linux/fs.h | 4 +++ 2 files changed, 81 insertions(+) diff --git a/fs/libfs.c b/fs/libfs.c index c297953db948..711eecc125bd 100644 --- a/fs/libfs.c +++ b/fs/libfs.c @@ -1776,6 +1776,83 @@ static const struct dentry_operations generic_ci_den= try_ops =3D { .d_revalidate =3D fscrypt_d_revalidate, #endif }; + +/** + * generic_ci_match() - Match a name (case-insensitively) with a dirent. + * This is a filesystem helper for comparison with directory entries. + * generic_ci_d_compare should be used in VFS' ->d_compare instead. + * + * @parent: Inode of the parent of the dirent under comparison + * @name: name under lookup. + * @folded_name: Optional pre-folded name under lookup + * @de_name: Dirent name. + * @de_name_len: dirent name length. + * + * Test whether a case-insensitive directory entry matches the filename + * being searched. If @folded_name is provided, it is used instead of + * recalculating the casefold of @name. + * + * Return: > 0 if the directory entry matches, 0 if it doesn't match, or + * < 0 on error. + */ +int generic_ci_match(const struct inode *parent, + const struct qstr *name, + const struct qstr *folded_name, + const u8 *de_name, u32 de_name_len) +{ + const struct super_block *sb =3D parent->i_sb; + const struct unicode_map *um =3D sb->s_encoding; + struct fscrypt_str decrypted_name =3D FSTR_INIT(NULL, de_name_len); + struct qstr dirent =3D QSTR_INIT(de_name, de_name_len); + int res =3D 0, match =3D 0; + + if (IS_ENCRYPTED(parent)) { + const struct fscrypt_str encrypted_name =3D + FSTR_INIT((u8 *) de_name, de_name_len); + + if (WARN_ON_ONCE(!fscrypt_has_encryption_key(parent))) + return -EINVAL; + + decrypted_name.name =3D kmalloc(de_name_len, GFP_KERNEL); + if (!decrypted_name.name) + return -ENOMEM; + res =3D fscrypt_fname_disk_to_usr(parent, 0, 0, &encrypted_name, + &decrypted_name); + if (res < 0) + goto out; + dirent.name =3D decrypted_name.name; + dirent.len =3D decrypted_name.len; + } + + /* + * Attempt a case-sensitive match first. It is cheaper and + * should cover most lookups, including all the sane + * applications that expect a case-sensitive filesystem. + */ + if (folded_name->name) { + if (dirent.len =3D=3D folded_name->len && + !memcmp(folded_name->name, dirent.name, dirent.len)) { + match =3D 1; + goto out; + } + res =3D utf8_strncasecmp_folded(um, folded_name, &dirent); + } else { + if (dirent.len =3D=3D name->len && + !memcmp(name->name, dirent.name, dirent.len) && + (!sb_has_strict_encoding(sb) || !utf8_validate(um, name))) { + match =3D 1; + goto out; + } + res =3D utf8_strncasecmp(um, name, &dirent); + } + +out: + kfree(decrypted_name.name); + if (res < 0) + return res; + return (match || !res); +} +EXPORT_SYMBOL(generic_ci_match); #endif =20 #ifdef CONFIG_FS_ENCRYPTION diff --git a/include/linux/fs.h b/include/linux/fs.h index ff1338109b54..690b37e1db95 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -3281,6 +3281,10 @@ extern int generic_file_fsync(struct file *, loff_t,= loff_t, int); extern int generic_check_addressable(unsigned, u64); =20 extern void generic_set_sb_d_ops(struct super_block *sb); +extern int generic_ci_match(const struct inode *parent, + const struct qstr *name, + const struct qstr *folded_name, + const u8 *de_name, u32 de_name_len); =20 static inline bool sb_has_encoding(const struct super_block *sb) { --=20 2.34.1