From: Daniel Rosenberg <drosen@google.com>
To: "Theodore Y . Ts'o" <tytso@mit.edu>,
Eric Biggers <ebiggers@kernel.org>,
Andreas Dilger <adilger.kernel@dilger.ca>,
linux-ext4@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
Gabriel Krisman Bertazi <krisman@collabora.com>,
kernel-team@android.com, Daniel Rosenberg <drosen@google.com>,
Paul Lawrence <paullawrence@google.com>
Subject: [PATCH 2/2] ext4: Optimize match for casefolded encrypted dirs
Date: Wed, 3 Feb 2021 09:07:45 +0000 [thread overview]
Message-ID: <20210203090745.4103054-3-drosen@google.com> (raw)
In-Reply-To: <20210203090745.4103054-1-drosen@google.com>
Matching names with casefolded encrypting directories requires
decrypting entries to confirm case since we are case preserving. We can
avoid needing to decrypt if our hash values don't match.
Signed-off-by: Daniel Rosenberg <drosen@google.com>
Signed-off-by: Paul Lawrence <paullawrence@google.com>
---
fs/ext4/ext4.h | 17 ++++++++-------
fs/ext4/namei.c | 55 ++++++++++++++++++++++++++-----------------------
2 files changed, 38 insertions(+), 34 deletions(-)
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 90a2c182e4d7..997f80cfe5df 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -2637,9 +2637,9 @@ extern unsigned ext4_free_clusters_after_init(struct super_block *sb,
ext4_fsblk_t ext4_inode_to_goal_block(struct inode *);
#ifdef CONFIG_UNICODE
-extern void ext4_fname_setup_ci_filename(struct inode *dir,
+extern int ext4_fname_setup_ci_filename(struct inode *dir,
const struct qstr *iname,
- struct fscrypt_str *fname);
+ struct ext4_filename *fname);
#endif
#ifdef CONFIG_FS_ENCRYPTION
@@ -2670,9 +2670,9 @@ static inline int ext4_fname_setup_filename(struct inode *dir,
ext4_fname_from_fscrypt_name(fname, &name);
#ifdef CONFIG_UNICODE
- ext4_fname_setup_ci_filename(dir, iname, &fname->cf_name);
+ err = ext4_fname_setup_ci_filename(dir, iname, fname);
#endif
- return 0;
+ return err;
}
static inline int ext4_fname_prepare_lookup(struct inode *dir,
@@ -2689,9 +2689,9 @@ static inline int ext4_fname_prepare_lookup(struct inode *dir,
ext4_fname_from_fscrypt_name(fname, &name);
#ifdef CONFIG_UNICODE
- ext4_fname_setup_ci_filename(dir, &dentry->d_name, &fname->cf_name);
+ err = ext4_fname_setup_ci_filename(dir, &dentry->d_name, fname);
#endif
- return 0;
+ return err;
}
static inline void ext4_fname_free_filename(struct ext4_filename *fname)
@@ -2716,15 +2716,16 @@ static inline int ext4_fname_setup_filename(struct inode *dir,
int lookup,
struct ext4_filename *fname)
{
+ int err = 0;
fname->usr_fname = iname;
fname->disk_name.name = (unsigned char *) iname->name;
fname->disk_name.len = iname->len;
#ifdef CONFIG_UNICODE
- ext4_fname_setup_ci_filename(dir, iname, &fname->cf_name);
+ err = ext4_fname_setup_ci_filename(dir, iname, fname);
#endif
- return 0;
+ return err;
}
static inline int ext4_fname_prepare_lookup(struct inode *dir,
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index 00b0b0cb4600..ff024bb613c0 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -799,7 +799,9 @@ dx_probe(struct ext4_filename *fname, struct inode *dir,
if (hinfo->hash_version <= DX_HASH_TEA)
hinfo->hash_version += EXT4_SB(dir->i_sb)->s_hash_unsigned;
hinfo->seed = EXT4_SB(dir->i_sb)->s_hash_seed;
- if (fname && fname_name(fname))
+ /* hash is already computed for encrypted casefolded directory */
+ if (fname && fname_name(fname) &&
+ !(IS_ENCRYPTED(dir) && IS_CASEFOLDED(dir)))
ext4fs_dirhash(dir, fname_name(fname), fname_len(fname), hinfo);
hash = hinfo->hash;
@@ -1364,19 +1366,21 @@ static int ext4_ci_compare(const struct inode *parent, const struct qstr *name,
return ret;
}
-void ext4_fname_setup_ci_filename(struct inode *dir, const struct qstr *iname,
- struct fscrypt_str *cf_name)
+int ext4_fname_setup_ci_filename(struct inode *dir, const struct qstr *iname,
+ struct ext4_filename *name)
{
+ struct fscrypt_str *cf_name = &name->cf_name;
+ struct dx_hash_info *hinfo = &name->hinfo;
int len;
if (!IS_CASEFOLDED(dir) || !dir->i_sb->s_encoding) {
cf_name->name = NULL;
- return;
+ return 0;
}
cf_name->name = kmalloc(EXT4_NAME_LEN, GFP_NOFS);
if (!cf_name->name)
- return;
+ return -ENOMEM;
len = utf8_casefold(dir->i_sb->s_encoding,
iname, cf_name->name,
@@ -1384,10 +1388,18 @@ void ext4_fname_setup_ci_filename(struct inode *dir, const struct qstr *iname,
if (len <= 0) {
kfree(cf_name->name);
cf_name->name = NULL;
- return;
}
cf_name->len = (unsigned) len;
+ if (!IS_ENCRYPTED(dir))
+ return 0;
+ hinfo->hash_version = DX_HASH_SIPHASH;
+ hinfo->seed = NULL;
+ if (cf_name->name)
+ ext4fs_dirhash(dir, cf_name->name, cf_name->len, hinfo);
+ else
+ ext4fs_dirhash(dir, iname->name, iname->len, hinfo);
+ return 0;
}
#endif
@@ -1417,16 +1429,12 @@ static bool ext4_match(struct inode *parent,
struct qstr cf = {.name = fname->cf_name.name,
.len = fname->cf_name.len};
if (IS_ENCRYPTED(parent)) {
- struct dx_hash_info hinfo;
-
- hinfo.hash_version = DX_HASH_SIPHASH;
- hinfo.seed = NULL;
- ext4fs_dirhash(parent, fname->cf_name.name,
- fname_len(fname), &hinfo);
- if (hinfo.hash != EXT4_DIRENT_HASH(de) ||
- hinfo.minor_hash !=
- EXT4_DIRENT_MINOR_HASH(de))
+ if (fname->hinfo.hash != EXT4_DIRENT_HASH(de) ||
+ fname->hinfo.minor_hash !=
+ EXT4_DIRENT_MINOR_HASH(de)) {
+
return 0;
+ }
}
return !ext4_ci_compare(parent, &cf, de->name,
de->name_len, true);
@@ -2061,15 +2069,11 @@ void ext4_insert_dentry(struct inode *dir,
de->name_len = fname_len(fname);
memcpy(de->name, fname_name(fname), fname_len(fname));
if (ext4_hash_in_dirent(dir)) {
- struct dx_hash_info hinfo;
+ struct dx_hash_info *hinfo = &fname->hinfo;
- hinfo.hash_version = DX_HASH_SIPHASH;
- hinfo.seed = NULL;
- ext4fs_dirhash(dir, fname_usr_name(fname),
- fname_len(fname), &hinfo);
- EXT4_DIRENT_HASHES(de)->hash = cpu_to_le32(hinfo.hash);
+ EXT4_DIRENT_HASHES(de)->hash = cpu_to_le32(hinfo->hash);
EXT4_DIRENT_HASHES(de)->minor_hash =
- cpu_to_le32(hinfo.minor_hash);
+ cpu_to_le32(hinfo->minor_hash);
}
}
@@ -2220,10 +2224,9 @@ static int make_indexed_dir(handle_t *handle, struct ext4_filename *fname,
if (fname->hinfo.hash_version <= DX_HASH_TEA)
fname->hinfo.hash_version += EXT4_SB(dir->i_sb)->s_hash_unsigned;
fname->hinfo.seed = EXT4_SB(dir->i_sb)->s_hash_seed;
- if (ext4_hash_in_dirent(dir))
- ext4fs_dirhash(dir, fname_usr_name(fname),
- fname_len(fname), &fname->hinfo);
- else
+
+ /* casefolded encrypted hashes are computed on fname setup */
+ if (!ext4_hash_in_dirent(dir))
ext4fs_dirhash(dir, fname_name(fname),
fname_len(fname), &fname->hinfo);
--
2.30.0.365.g02bc693789-goog
prev parent reply other threads:[~2021-02-03 9:13 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-03 9:07 [PATCH 0/2] Reconcile Encryption and Casefolding in Ext4 Daniel Rosenberg
2021-02-03 9:07 ` [PATCH 1/2] ext4: Handle casefolding with encryption Daniel Rosenberg
[not found] ` <56BC7E2D-A303-45AE-93B6-D8921189F604@dilger.ca>
2021-02-03 16:31 ` Theodore Ts'o
2021-02-09 23:22 ` Theodore Ts'o
2021-02-10 3:03 ` Andreas Dilger
2021-02-10 4:03 ` Theodore Ts'o
2021-02-17 4:01 ` Daniel Rosenberg
2021-02-17 16:08 ` Theodore Ts'o
2021-02-17 22:48 ` Andreas Dilger
2021-02-18 23:21 ` Daniel Rosenberg
2021-02-26 5:14 ` Andreas Dilger
2021-02-19 15:21 ` Theodore Ts'o
2021-02-03 9:07 ` Daniel Rosenberg [this message]
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