Return-Path: Received: from bhuna.collabora.co.uk ([46.235.227.227]:45600 "EHLO bhuna.collabora.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726435AbeIYECu (ORCPT ); Tue, 25 Sep 2018 00:02:50 -0400 From: Gabriel Krisman Bertazi To: tytso@mit.edu Cc: linux-ext4@vger.kernel.org, Gabriel Krisman Bertazi Subject: [PATCH RESEND v2 23/25] ext4: Implement encoding-aware dcache hooks Date: Mon, 24 Sep 2018 17:56:53 -0400 Message-Id: <20180924215655.3676-24-krisman@collabora.co.uk> In-Reply-To: <20180924215655.3676-1-krisman@collabora.co.uk> References: <20180924215655.3676-1-krisman@collabora.co.uk> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-ext4-owner@vger.kernel.org List-ID: This patch implements dcache hooks to improve the handling of encoding-aware file names by the vfs dcache. d_hash() is implemented as the hash of the normalized string, such that have a well-known bucket for all the equivalencies of the same string. d_compare uses the nls_strncmp() infrastructure, which should handle the comparison of equivalent names as well. If the filesystem's normalization type is PLAIN, though, we can just reuse the VFS hash. Changes since v1: - Use qstr->len instead of strlen. - Guard code with CONFIG_NLS. Signed-off-by: Gabriel Krisman Bertazi --- fs/ext4/dir.c | 45 +++++++++++++++++++++++++++++++++++++++++++++ fs/ext4/ext4.h | 3 +++ fs/ext4/super.c | 6 ++++++ 3 files changed, 54 insertions(+) diff --git a/fs/ext4/dir.c b/fs/ext4/dir.c index f93f9881ec18..37a36cdadaaf 100644 --- a/fs/ext4/dir.c +++ b/fs/ext4/dir.c @@ -26,6 +26,7 @@ #include #include #include +#include #include "ext4.h" #include "xattr.h" @@ -662,3 +663,47 @@ const struct file_operations ext4_dir_operations = { .open = ext4_dir_open, .release = ext4_release_dir, }; + +#ifdef CONFIG_NLS +static int ext4_d_compare(const struct dentry *dentry, unsigned int len, + const char *str, const struct qstr *name) +{ + struct nls_table *charset = EXT4_SB(dentry->d_sb)->encoding; + + return nls_strncmp(charset, str, len, name->name, name->len); +} + +static int ext4_d_hash(const struct dentry *dentry, struct qstr *q) +{ + const struct nls_table *charset = EXT4_SB(dentry->d_sb)->encoding; + unsigned char *norm; + int len, ret = 0; + + /* If normalization is TYPE_PLAIN, we can just reuse the vfs + * hash. */ + if (IS_NORMALIZATION_TYPE_ALL_PLAIN(charset)) + return 0; + + norm = kmalloc(PATH_MAX, GFP_ATOMIC); + if (!norm) + return -ENOMEM; + + len = nls_normalize(charset, q->name, q->len, norm, PATH_MAX); + + if (len < 0) { + ret = -EINVAL; + goto out; + } + + q->hash = full_name_hash(dentry, norm, len); + +out: + kfree (norm); + return ret; +} + +const struct dentry_operations ext4_dentry_ops = { + .d_hash = ext4_d_hash, + .d_compare = ext4_d_compare, +}; +#endif diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h index f7932d70b9fd..586e733c8915 100644 --- a/fs/ext4/ext4.h +++ b/fs/ext4/ext4.h @@ -2979,6 +2979,9 @@ static inline void ext4_unlock_group(struct super_block *sb, /* dir.c */ extern const struct file_operations ext4_dir_operations; +#ifdef CONFIG_NLS +extern const struct dentry_operations ext4_dentry_ops; +#endif /* file.c */ extern const struct inode_operations ext4_file_inode_operations; diff --git a/fs/ext4/super.c b/fs/ext4/super.c index f70c947c9850..a9809a2d371c 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -4480,6 +4480,12 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent) iput(root); goto failed_mount4; } + +#ifdef CONFIG_NLS + if (sbi->encoding) + sb->s_d_op = &ext4_dentry_ops; +#endif + sb->s_root = d_make_root(root); if (!sb->s_root) { ext4_msg(sb, KERN_ERR, "get root dentry failed"); -- 2.19.0