[PATCH v7 0/8] Clean up the case-insensitive lookup path

[PATCH v7 0/8] Clean up the case-insensitive lookup path

[Gabriel Krisman Bertazi]

Hi Eric, Ted,

This is v7 of this series (thank you for the feedback!) .  This picks up
a few r-b tags and has one small fix asked by Eric to handle a corner
case in ext4_match when IS_ENCRYPTED() and the key is added during
lookup.

* Original commit letter

The case-insensitive implementations in f2fs and ext4 have quite a bit
of duplicated code.  This series simplifies the ext4 version, with the
goal of extracting ext4_ci_compare into a helper library that can be
used by both filesystems.  It also reduces the clutter from many
codeguards for CONFIG_UNICODE; as requested by Linus, they are part of
the codeflow now.

While there, I noticed we can leverage the utf8 functions to detect
encoded names that are corrupted in the filesystem. Therefore, it also
adds an ext4 error on that scenario, to mark the filesystem as
corrupted.

This series survived passes of xfstests -g quick.

Gabriel Krisman Bertazi (8):
  ext4: Simplify the handling of cached insensitive names
  f2fs: Simplify the handling of cached insensitive names
  libfs: Introduce case-insensitive string comparison helper
  ext4: Reuse generic_ci_match for ci comparisons
  f2fs: Reuse generic_ci_match for ci comparisons
  ext4: Log error when lookup of encoded dentry fails
  ext4: Move CONFIG_UNICODE defguards into the code flow
  f2fs: Move CONFIG_UNICODE defguards into the code flow

 fs/ext4/ext4.h     |  49 +++++++++--------
 fs/ext4/namei.c    | 130 ++++++++++++++++-----------------------------
 fs/ext4/super.c    |   4 +-
 fs/f2fs/dir.c      | 103 +++++++++++------------------------
 fs/f2fs/f2fs.h     |  15 +++++-
 fs/f2fs/namei.c    |  11 ++--
 fs/f2fs/recovery.c |   5 +-
 fs/f2fs/super.c    |   8 +--
 fs/libfs.c         |  68 ++++++++++++++++++++++++
 include/linux/fs.h |   4 ++
 10 files changed, 197 insertions(+), 200 deletions(-)

-- 
2.36.1

[PATCH v7 1/8] ext4: Simplify the handling of cached insensitive names

[Gabriel Krisman Bertazi]

Keeping it as qstr avoids the unnecessary conversion in ext4_match

Reviewed-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com>

---
Changes since v1:
  - Simplify hunk (eric)
---
 fs/ext4/ext4.h  |  2 +-
 fs/ext4/namei.c | 23 +++++++++++------------
 2 files changed, 12 insertions(+), 13 deletions(-)

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index a743b1e3b89e..93a28fcb2e22 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -2490,7 +2490,7 @@ struct ext4_filename {
 	struct fscrypt_str crypto_buf;
 #endif
 #if IS_ENABLED(CONFIG_UNICODE)
-	struct fscrypt_str cf_name;
+	struct qstr cf_name;
 #endif
 };
 
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index 767b4bfe39c3..206fcf8fdc16 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -1373,7 +1373,8 @@ static int ext4_ci_compare(const struct inode *parent, const struct qstr *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 qstr *cf_name = &name->cf_name;
+	unsigned char *buf;
 	struct dx_hash_info *hinfo = &name->hinfo;
 	int len;
 
@@ -1383,18 +1384,18 @@ int ext4_fname_setup_ci_filename(struct inode *dir, const struct qstr *iname,
 		return 0;
 	}
 
-	cf_name->name = kmalloc(EXT4_NAME_LEN, GFP_NOFS);
-	if (!cf_name->name)
+	buf = kmalloc(EXT4_NAME_LEN, GFP_NOFS);
+	if (!buf)
 		return -ENOMEM;
 
-	len = utf8_casefold(dir->i_sb->s_encoding,
-			    iname, cf_name->name,
-			    EXT4_NAME_LEN);
+	len = utf8_casefold(dir->i_sb->s_encoding, iname, buf, EXT4_NAME_LEN);
 	if (len <= 0) {
-		kfree(cf_name->name);
-		cf_name->name = NULL;
+		kfree(buf);
+		buf = NULL;
 	}
+	cf_name->name = buf;
 	cf_name->len = (unsigned) len;
+
 	if (!IS_ENCRYPTED(dir))
 		return 0;
 
@@ -1432,8 +1433,6 @@ static bool ext4_match(struct inode *parent,
 	if (parent->i_sb->s_encoding && IS_CASEFOLDED(parent) &&
 	    (!IS_ENCRYPTED(parent) || fscrypt_has_encryption_key(parent))) {
 		if (fname->cf_name.name) {
-			struct qstr cf = {.name = fname->cf_name.name,
-					  .len = fname->cf_name.len};
 			if (IS_ENCRYPTED(parent)) {
 				if (fname->hinfo.hash != EXT4_DIRENT_HASH(de) ||
 					fname->hinfo.minor_hash !=
@@ -1442,8 +1441,8 @@ static bool ext4_match(struct inode *parent,
 					return false;
 				}
 			}
-			return !ext4_ci_compare(parent, &cf, de->name,
-							de->name_len, true);
+			return !ext4_ci_compare(parent, &fname->cf_name,
+						de->name, de->name_len, true);
 		}
 		return !ext4_ci_compare(parent, fname->usr_fname, de->name,
 						de->name_len, false);
-- 
2.36.1

[PATCH v7 2/8] f2fs: Simplify the handling of cached insensitive names

[Gabriel Krisman Bertazi]

Keeping it as qstr avoids the unnecessary conversion in f2fs_match

Reviewed-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com>

---
Changes since v4:
  - Fix inconsistent return on error (eric)
---
 fs/f2fs/dir.c      | 51 ++++++++++++++++++++++++++--------------------
 fs/f2fs/f2fs.h     | 15 +++++++++++++-
 fs/f2fs/recovery.c |  5 +----
 3 files changed, 44 insertions(+), 27 deletions(-)

diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c
index 166f08623362..167a04074a2e 100644
--- a/fs/f2fs/dir.c
+++ b/fs/f2fs/dir.c
@@ -75,34 +75,48 @@ unsigned char f2fs_get_de_type(struct f2fs_dir_entry *de)
 	return DT_UNKNOWN;
 }
 
+#if IS_ENABLED(CONFIG_UNICODE)
 /* If @dir is casefolded, initialize @fname->cf_name from @fname->usr_fname. */
 int f2fs_init_casefolded_name(const struct inode *dir,
 			      struct f2fs_filename *fname)
 {
-#if IS_ENABLED(CONFIG_UNICODE)
 	struct super_block *sb = dir->i_sb;
+	unsigned char *buf;
+	int len;
 
 	if (IS_CASEFOLDED(dir)) {
-		fname->cf_name.name = f2fs_kmem_cache_alloc(f2fs_cf_name_slab,
+		buf = f2fs_kmem_cache_alloc(f2fs_cf_name_slab,
 					GFP_NOFS, false, F2FS_SB(sb));
-		if (!fname->cf_name.name)
+		if (!buf)
 			return -ENOMEM;
-		fname->cf_name.len = utf8_casefold(sb->s_encoding,
-						   fname->usr_fname,
-						   fname->cf_name.name,
-						   F2FS_NAME_LEN);
-		if ((int)fname->cf_name.len <= 0) {
-			kmem_cache_free(f2fs_cf_name_slab, fname->cf_name.name);
-			fname->cf_name.name = NULL;
+
+		len = utf8_casefold(sb->s_encoding, fname->usr_fname,
+				    buf, F2FS_NAME_LEN);
+		if (len <= 0) {
+			kmem_cache_free(f2fs_cf_name_slab, buf);
 			if (sb_has_strict_encoding(sb))
 				return -EINVAL;
 			/* fall back to treating name as opaque byte sequence */
+			return 0;
 		}
+		fname->cf_name.name = buf;
+		fname->cf_name.len = len;
 	}
-#endif
+
 	return 0;
 }
 
+void f2fs_free_casefolded_name(struct f2fs_filename *fname)
+{
+	unsigned char *buf = (unsigned char *)fname->cf_name.name;
+
+	if (buf) {
+		kmem_cache_free(f2fs_cf_name_slab, buf);
+		fname->cf_name.name = NULL;
+	}
+}
+#endif /* CONFIG_UNICODE */
+
 static int __f2fs_setup_filename(const struct inode *dir,
 				 const struct fscrypt_name *crypt_name,
 				 struct f2fs_filename *fname)
@@ -174,12 +188,7 @@ void f2fs_free_filename(struct f2fs_filename *fname)
 	kfree(fname->crypto_buf.name);
 	fname->crypto_buf.name = NULL;
 #endif
-#if IS_ENABLED(CONFIG_UNICODE)
-	if (fname->cf_name.name) {
-		kmem_cache_free(f2fs_cf_name_slab, fname->cf_name.name);
-		fname->cf_name.name = NULL;
-	}
-#endif
+	f2fs_free_casefolded_name(fname);
 }
 
 static unsigned long dir_block_index(unsigned int level,
@@ -267,11 +276,9 @@ static inline int f2fs_match_name(const struct inode *dir,
 	struct fscrypt_name f;
 
 #if IS_ENABLED(CONFIG_UNICODE)
-	if (fname->cf_name.name) {
-		struct qstr cf = FSTR_TO_QSTR(&fname->cf_name);
-
-		return f2fs_match_ci_name(dir, &cf, de_name, de_name_len);
-	}
+	if (fname->cf_name.name)
+		return f2fs_match_ci_name(dir, &fname->cf_name,
+					  de_name, de_name_len);
 #endif
 	f.usr_fname = fname->usr_fname;
 	f.disk_name = fname->disk_name;
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 68b44015514f..5eb88be507e7 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -497,7 +497,7 @@ struct f2fs_filename {
 	 * NULL.  In all these cases we fall back to treating the name as an
 	 * opaque byte sequence.
 	 */
-	struct fscrypt_str cf_name;
+	struct qstr cf_name;
 #endif
 };
 
@@ -3343,8 +3343,21 @@ struct dentry *f2fs_get_parent(struct dentry *child);
  * dir.c
  */
 unsigned char f2fs_get_de_type(struct f2fs_dir_entry *de);
+#if IS_ENABLED(CONFIG_UNICODE)
 int f2fs_init_casefolded_name(const struct inode *dir,
 			      struct f2fs_filename *fname);
+void f2fs_free_casefolded_name(struct f2fs_filename *fname);
+#else
+static inline int f2fs_init_casefolded_name(const struct inode *dir,
+					    struct f2fs_filename *fname)
+{
+	return 0;
+}
+static inline void f2fs_free_casefolded_name(struct f2fs_filename *fname)
+{
+}
+#endif /* CONFIG_UNICODE */
+
 int f2fs_setup_filename(struct inode *dir, const struct qstr *iname,
 			int lookup, struct f2fs_filename *fname);
 int f2fs_prepare_lookup(struct inode *dir, struct dentry *dentry,
diff --git a/fs/f2fs/recovery.c b/fs/f2fs/recovery.c
index 79773d322c47..3c3a8abf6953 100644
--- a/fs/f2fs/recovery.c
+++ b/fs/f2fs/recovery.c
@@ -149,11 +149,8 @@ static int init_recovered_filename(const struct inode *dir,
 		if (err)
 			return err;
 		f2fs_hash_filename(dir, fname);
-#if IS_ENABLED(CONFIG_UNICODE)
 		/* Case-sensitive match is fine for recovery */
-		kmem_cache_free(f2fs_cf_name_slab, fname->cf_name.name);
-		fname->cf_name.name = NULL;
-#endif
+		f2fs_free_casefolded_name(fname);
 	} else {
 		f2fs_hash_filename(dir, fname);
 	}
-- 
2.36.1

[PATCH v7 3/8] libfs: Introduce case-insensitive string comparison helper

[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.

Reviewed-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com>

---
Changes since v5:
  (eric)
  - Rename variable err -> res
  - Retype de_name_len from size_t to u32
  - Bring WARN_ON_ONCE(!fscrypt_has_encryption_key) from f2fs implementation
---
 fs/libfs.c         | 68 ++++++++++++++++++++++++++++++++++++++++++++++
 include/linux/fs.h |  4 +++
 2 files changed, 72 insertions(+)

diff --git a/fs/libfs.c b/fs/libfs.c
index 974125270a42..f1d88cd903f8 100644
--- a/fs/libfs.c
+++ b/fs/libfs.c
@@ -1465,6 +1465,74 @@ static const struct dentry_operations generic_ci_dentry_ops = {
 	.d_hash = generic_ci_d_hash,
 	.d_compare = generic_ci_d_compare,
 };
+
+/**
+ * generic_ci_match() - Match a name (case-insensitively) with a dirent.
+ * @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 = parent->i_sb;
+	const struct unicode_map *um = sb->s_encoding;
+	struct fscrypt_str decrypted_name = FSTR_INIT(NULL, de_name_len);
+	struct qstr dirent = QSTR_INIT(de_name, de_name_len);
+	int res, match = false;
+
+	if (IS_ENCRYPTED(parent)) {
+		const struct fscrypt_str encrypted_name =
+			FSTR_INIT((u8 *) de_name, de_name_len);
+
+		if (WARN_ON_ONCE(!fscrypt_has_encryption_key(parent)))
+			return -EINVAL;
+
+		decrypted_name.name = kmalloc(de_name_len, GFP_KERNEL);
+		if (!decrypted_name.name)
+			return -ENOMEM;
+		res = fscrypt_fname_disk_to_usr(parent, 0, 0, &encrypted_name,
+						&decrypted_name);
+		if (res < 0)
+			goto out;
+		dirent.name = decrypted_name.name;
+		dirent.len = decrypted_name.len;
+	}
+
+	if (folded_name->name)
+		res = utf8_strncasecmp_folded(um, folded_name, &dirent);
+	else
+		res = utf8_strncasecmp(um, name, &dirent);
+
+	if (!res)
+		match = true;
+	else if (res < 0 && !sb_has_strict_encoding(sb)) {
+		/*
+		 * In non-strict mode, fallback to a byte comparison if
+		 * the names have invalid characters.
+		 */
+		res = 0;
+		match = ((name->len == dirent.len) &&
+			 !memcmp(name->name, dirent.name, dirent.len));
+	}
+
+out:
+	kfree(decrypted_name.name);
+	return (res >= 0) ? match : res;
+}
+EXPORT_SYMBOL(generic_ci_match);
 #endif
 
 #ifdef CONFIG_FS_ENCRYPTION
diff --git a/include/linux/fs.h b/include/linux/fs.h
index e2d892b201b0..4c2b781f667a 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -3359,6 +3359,10 @@ extern int generic_file_fsync(struct file *, loff_t, loff_t, int);
 extern int generic_check_addressable(unsigned, u64);
 
 extern void generic_set_encrypted_ci_d_ops(struct dentry *dentry);
+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);
 
 #ifdef CONFIG_MIGRATION
 extern int buffer_migrate_page(struct address_space *,
-- 
2.36.1

[PATCH v7 4/8] ext4: Reuse generic_ci_match for ci comparisons

[Gabriel Krisman Bertazi]

Instead of reimplementing ext4_match_ci, use the new libfs helper.

It also adds a comment explaining why fname->cf_name.name must be
checked prior to the encryption hash optimization, because that tripped
me before.

Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com>

---
Changes since v6:
  - Readd cf_name != NULL on hash verification and comment explaining it (eric)
---
 fs/ext4/namei.c | 91 +++++++++++++++----------------------------------
 1 file changed, 27 insertions(+), 64 deletions(-)

diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index 206fcf8fdc16..5e68dd6ad9b8 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -1318,58 +1318,6 @@ static void dx_insert_block(struct dx_frame *frame, u32 hash, ext4_lblk_t block)
 }
 
 #if IS_ENABLED(CONFIG_UNICODE)
-/*
- * Test whether a case-insensitive directory entry matches the filename
- * being searched for.  If quick is set, assume the name being looked up
- * is already in the casefolded form.
- *
- * Returns: 0 if the directory entry matches, more than 0 if it
- * doesn't match or less than zero on error.
- */
-static int ext4_ci_compare(const struct inode *parent, const struct qstr *name,
-			   u8 *de_name, size_t de_name_len, bool quick)
-{
-	const struct super_block *sb = parent->i_sb;
-	const struct unicode_map *um = sb->s_encoding;
-	struct fscrypt_str decrypted_name = FSTR_INIT(NULL, de_name_len);
-	struct qstr entry = QSTR_INIT(de_name, de_name_len);
-	int ret;
-
-	if (IS_ENCRYPTED(parent)) {
-		const struct fscrypt_str encrypted_name =
-				FSTR_INIT(de_name, de_name_len);
-
-		decrypted_name.name = kmalloc(de_name_len, GFP_KERNEL);
-		if (!decrypted_name.name)
-			return -ENOMEM;
-		ret = fscrypt_fname_disk_to_usr(parent, 0, 0, &encrypted_name,
-						&decrypted_name);
-		if (ret < 0)
-			goto out;
-		entry.name = decrypted_name.name;
-		entry.len = decrypted_name.len;
-	}
-
-	if (quick)
-		ret = utf8_strncasecmp_folded(um, name, &entry);
-	else
-		ret = utf8_strncasecmp(um, name, &entry);
-	if (ret < 0) {
-		/* Handle invalid character sequence as either an error
-		 * or as an opaque byte sequence.
-		 */
-		if (sb_has_strict_encoding(sb))
-			ret = -EINVAL;
-		else if (name->len != entry.len)
-			ret = 1;
-		else
-			ret = !!memcmp(name->name, entry.name, entry.len);
-	}
-out:
-	kfree(decrypted_name.name);
-	return ret;
-}
-
 int ext4_fname_setup_ci_filename(struct inode *dir, const struct qstr *iname,
 				  struct ext4_filename *name)
 {
@@ -1432,20 +1380,35 @@ static bool ext4_match(struct inode *parent,
 #if IS_ENABLED(CONFIG_UNICODE)
 	if (parent->i_sb->s_encoding && IS_CASEFOLDED(parent) &&
 	    (!IS_ENCRYPTED(parent) || fscrypt_has_encryption_key(parent))) {
-		if (fname->cf_name.name) {
-			if (IS_ENCRYPTED(parent)) {
-				if (fname->hinfo.hash != EXT4_DIRENT_HASH(de) ||
-					fname->hinfo.minor_hash !=
-						EXT4_DIRENT_MINOR_HASH(de)) {
+		int ret;
 
-					return false;
-				}
-			}
-			return !ext4_ci_compare(parent, &fname->cf_name,
-						de->name, de->name_len, true);
+		/*
+		 * Just checking IS_ENCRYPTED(parent) below is not
+		 * sufficient to decide whether one can use the hash for
+		 * skipping the string comparison, because the key might
+		 * have been added right after
+		 * ext4_fname_setup_ci_filename().  In this case, a hash
+		 * mismatch will be a false negative.  Therefore, make
+		 * sure cf_name was properly initialized before
+		 * considering the calculated hash.
+		 */
+		if (IS_ENCRYPTED(parent) && fname->cf_name.name
+		    (fname->hinfo.hash != EXT4_DIRENT_HASH(de) ||
+		     fname->hinfo.minor_hash != EXT4_DIRENT_MINOR_HASH(de)))
+			return false;
+
+		ret = generic_ci_match(parent, fname->usr_fname,
+				       &fname->cf_name, de->name,
+				       de->name_len);
+		if (ret < 0) {
+			/*
+			 * Treat comparison errors as not a match.  The
+			 * only case where it happens is on a disk
+			 * corruption or ENOMEM.
+			 */
+			return false;
 		}
-		return !ext4_ci_compare(parent, fname->usr_fname, de->name,
-						de->name_len, false);
+		return ret;
 	}
 #endif
 
-- 
2.36.1

[PATCH v7 5/8] f2fs: Reuse generic_ci_match for ci comparisons

[Gabriel Krisman Bertazi]

Now that ci_match is part of libfs, make f2fs reuse it instead of having
a different implementation.

Reviewed-by: Chao Yu <chao@kernel.org>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com>

---
Changes since v3:
  - Drop cast (eric)
  - fix unused variable iff !CONFIG_UNICODE (lkp)
---
 fs/f2fs/dir.c | 58 ++++-----------------------------------------------
 1 file changed, 4 insertions(+), 54 deletions(-)

diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c
index 167a04074a2e..4e4b2b190188 100644
--- a/fs/f2fs/dir.c
+++ b/fs/f2fs/dir.c
@@ -217,58 +217,6 @@ static struct f2fs_dir_entry *find_in_block(struct inode *dir,
 	return f2fs_find_target_dentry(&d, fname, max_slots);
 }
 
-#if IS_ENABLED(CONFIG_UNICODE)
-/*
- * Test whether a case-insensitive directory entry matches the filename
- * being searched for.
- *
- * Returns 1 for a match, 0 for no match, and -errno on an error.
- */
-static int f2fs_match_ci_name(const struct inode *dir, const struct qstr *name,
-			       const u8 *de_name, u32 de_name_len)
-{
-	const struct super_block *sb = dir->i_sb;
-	const struct unicode_map *um = sb->s_encoding;
-	struct fscrypt_str decrypted_name = FSTR_INIT(NULL, de_name_len);
-	struct qstr entry = QSTR_INIT(de_name, de_name_len);
-	int res;
-
-	if (IS_ENCRYPTED(dir)) {
-		const struct fscrypt_str encrypted_name =
-			FSTR_INIT((u8 *)de_name, de_name_len);
-
-		if (WARN_ON_ONCE(!fscrypt_has_encryption_key(dir)))
-			return -EINVAL;
-
-		decrypted_name.name = kmalloc(de_name_len, GFP_KERNEL);
-		if (!decrypted_name.name)
-			return -ENOMEM;
-		res = fscrypt_fname_disk_to_usr(dir, 0, 0, &encrypted_name,
-						&decrypted_name);
-		if (res < 0)
-			goto out;
-		entry.name = decrypted_name.name;
-		entry.len = decrypted_name.len;
-	}
-
-	res = utf8_strncasecmp_folded(um, name, &entry);
-	/*
-	 * In strict mode, ignore invalid names.  In non-strict mode,
-	 * fall back to treating them as opaque byte sequences.
-	 */
-	if (res < 0 && !sb_has_strict_encoding(sb)) {
-		res = name->len == entry.len &&
-				memcmp(name->name, entry.name, name->len) == 0;
-	} else {
-		/* utf8_strncasecmp_folded returns 0 on match */
-		res = (res == 0);
-	}
-out:
-	kfree(decrypted_name.name);
-	return res;
-}
-#endif /* CONFIG_UNICODE */
-
 static inline int f2fs_match_name(const struct inode *dir,
 				   const struct f2fs_filename *fname,
 				   const u8 *de_name, u32 de_name_len)
@@ -277,8 +225,10 @@ static inline int f2fs_match_name(const struct inode *dir,
 
 #if IS_ENABLED(CONFIG_UNICODE)
 	if (fname->cf_name.name)
-		return f2fs_match_ci_name(dir, &fname->cf_name,
-					  de_name, de_name_len);
+		return generic_ci_match(dir, fname->usr_fname,
+					&fname->cf_name,
+					de_name, de_name_len);
+
 #endif
 	f.usr_fname = fname->usr_fname;
 	f.disk_name = fname->disk_name;
-- 
2.36.1

[PATCH v7 6/8] ext4: Log error when lookup of encoded dentry fails

[Gabriel Krisman Bertazi]

If the volume is in strict mode, ext4_ci_compare can report a broken
encoding name.  This will not trigger on a bad lookup, which is caught
earlier, only if the actual disk name is bad.

Reviewed-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com>

---

changes since v4:
  - Reword error message (Eric)

Changes since v1:
  - reword error message "file in directory" -> "filename" (Eric)
---
 fs/ext4/namei.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index 5e68dd6ad9b8..f4593dc3e593 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -1406,6 +1406,9 @@ static bool ext4_match(struct inode *parent,
 			 * only case where it happens is on a disk
 			 * corruption or ENOMEM.
 			 */
+			if (ret == -EINVAL)
+				EXT4_ERROR_INODE(parent,
+					"Directory contains filename that is invalid UTF-8");
 			return false;
 		}
 		return ret;
-- 
2.36.1

[PATCH v7 7/8] ext4: Move CONFIG_UNICODE defguards into the code flow

[Gabriel Krisman Bertazi]

Instead of a bunch of ifdefs, make the unicode built checks part of the
code flow where possible, as requested by Torvalds.

Reviewed-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com>

---
Changes since v5:
  - Drop err variable (eric)
Changes since v4:
  - Create stub for !CONFIG_UNICODE case (eric)
---
 fs/ext4/ext4.h  | 47 +++++++++++++++++++++++------------------------
 fs/ext4/namei.c | 15 ++++++---------
 fs/ext4/super.c |  4 +---
 3 files changed, 30 insertions(+), 36 deletions(-)

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 93a28fcb2e22..4bc3649e3385 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -2727,8 +2727,24 @@ ext4_fsblk_t ext4_inode_to_goal_block(struct inode *);
 
 #if IS_ENABLED(CONFIG_UNICODE)
 extern int ext4_fname_setup_ci_filename(struct inode *dir,
-					 const struct qstr *iname,
-					 struct ext4_filename *fname);
+					const struct qstr *iname,
+					struct ext4_filename *fname);
+
+static inline void ext4_fname_free_ci_filename(struct ext4_filename *fname)
+{
+	kfree(fname->cf_name.name);
+	fname->cf_name.name = NULL;
+}
+#else
+static inline int ext4_fname_setup_ci_filename(struct inode *dir,
+					       const struct qstr *iname,
+					       struct ext4_filename *fname)
+{
+	return 0;
+}
+static inline void ext4_fname_free_ci_filename(struct ext4_filename *fname)
+{
+}
 #endif
 
 #ifdef CONFIG_FS_ENCRYPTION
@@ -2758,10 +2774,7 @@ static inline int ext4_fname_setup_filename(struct inode *dir,
 
 	ext4_fname_from_fscrypt_name(fname, &name);
 
-#if IS_ENABLED(CONFIG_UNICODE)
-	err = ext4_fname_setup_ci_filename(dir, iname, fname);
-#endif
-	return err;
+	return ext4_fname_setup_ci_filename(dir, iname, fname);
 }
 
 static inline int ext4_fname_prepare_lookup(struct inode *dir,
@@ -2777,10 +2790,7 @@ static inline int ext4_fname_prepare_lookup(struct inode *dir,
 
 	ext4_fname_from_fscrypt_name(fname, &name);
 
-#if IS_ENABLED(CONFIG_UNICODE)
-	err = ext4_fname_setup_ci_filename(dir, &dentry->d_name, fname);
-#endif
-	return err;
+	return ext4_fname_setup_ci_filename(dir, &dentry->d_name, fname);
 }
 
 static inline void ext4_fname_free_filename(struct ext4_filename *fname)
@@ -2794,10 +2804,7 @@ static inline void ext4_fname_free_filename(struct ext4_filename *fname)
 	fname->usr_fname = NULL;
 	fname->disk_name.name = NULL;
 
-#if IS_ENABLED(CONFIG_UNICODE)
-	kfree(fname->cf_name.name);
-	fname->cf_name.name = NULL;
-#endif
+	ext4_fname_free_ci_filename(fname);
 }
 #else /* !CONFIG_FS_ENCRYPTION */
 static inline int ext4_fname_setup_filename(struct inode *dir,
@@ -2805,16 +2812,11 @@ 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;
 
-#if IS_ENABLED(CONFIG_UNICODE)
-	err = ext4_fname_setup_ci_filename(dir, iname, fname);
-#endif
-
-	return err;
+	return ext4_fname_setup_ci_filename(dir, iname, fname);
 }
 
 static inline int ext4_fname_prepare_lookup(struct inode *dir,
@@ -2826,10 +2828,7 @@ static inline int ext4_fname_prepare_lookup(struct inode *dir,
 
 static inline void ext4_fname_free_filename(struct ext4_filename *fname)
 {
-#if IS_ENABLED(CONFIG_UNICODE)
-	kfree(fname->cf_name.name);
-	fname->cf_name.name = NULL;
-#endif
+	ext4_fname_free_ci_filename(fname);
 }
 #endif /* !CONFIG_FS_ENCRYPTION */
 
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index f4593dc3e593..ce1133738f40 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -1765,8 +1765,7 @@ static struct dentry *ext4_lookup(struct inode *dir, struct dentry *dentry, unsi
 		}
 	}
 
-#if IS_ENABLED(CONFIG_UNICODE)
-	if (!inode && IS_CASEFOLDED(dir)) {
+	if (IS_ENABLED(CONFIG_UNICODE) && !inode && IS_CASEFOLDED(dir)) {
 		/* Eventually we want to call d_add_ci(dentry, NULL)
 		 * for negative dentries in the encoding case as
 		 * well.  For now, prevent the negative dentry
@@ -1774,7 +1773,7 @@ static struct dentry *ext4_lookup(struct inode *dir, struct dentry *dentry, unsi
 		 */
 		return NULL;
 	}
-#endif
+
 	return d_splice_alias(inode, dentry);
 }
 
@@ -3091,16 +3090,14 @@ static int ext4_rmdir(struct inode *dir, struct dentry *dentry)
 	ext4_fc_track_unlink(handle, dentry);
 	retval = ext4_mark_inode_dirty(handle, dir);
 
-#if IS_ENABLED(CONFIG_UNICODE)
 	/* VFS negative dentries are incompatible with Encoding and
 	 * Case-insensitiveness. Eventually we'll want avoid
 	 * invalidating the dentries here, alongside with returning the
 	 * negative dentries at ext4_lookup(), when it is better
 	 * supported by the VFS for the CI case.
 	 */
-	if (IS_CASEFOLDED(dir))
+	if (IS_ENABLED(CONFIG_UNICODE) && IS_CASEFOLDED(dir))
 		d_invalidate(dentry);
-#endif
 
 end_rmdir:
 	brelse(bh);
@@ -3196,16 +3193,16 @@ static int ext4_unlink(struct inode *dir, struct dentry *dentry)
 	retval = __ext4_unlink(handle, dir, &dentry->d_name, d_inode(dentry));
 	if (!retval)
 		ext4_fc_track_unlink(handle, dentry);
-#if IS_ENABLED(CONFIG_UNICODE)
+
 	/* VFS negative dentries are incompatible with Encoding and
 	 * Case-insensitiveness. Eventually we'll want avoid
 	 * invalidating the dentries here, alongside with returning the
 	 * negative dentries at ext4_lookup(), when it is  better
 	 * supported by the VFS for the CI case.
 	 */
-	if (IS_CASEFOLDED(dir))
+	if (IS_ENABLED(CONFIG_UNICODE) && IS_CASEFOLDED(dir))
 		d_invalidate(dentry);
-#endif
+
 	if (handle)
 		ext4_journal_stop(handle);
 
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 1847b46af808..fa0004459dd6 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -3645,14 +3645,12 @@ int ext4_feature_set_ok(struct super_block *sb, int readonly)
 		return 0;
 	}
 
-#if !IS_ENABLED(CONFIG_UNICODE)
-	if (ext4_has_feature_casefold(sb)) {
+	if (!IS_ENABLED(CONFIG_UNICODE) && ext4_has_feature_casefold(sb)) {
 		ext4_msg(sb, KERN_ERR,
 			 "Filesystem with casefold feature cannot be "
 			 "mounted without CONFIG_UNICODE");
 		return 0;
 	}
-#endif
 
 	if (readonly)
 		return 1;
-- 
2.36.1

[PATCH v7 8/8] f2fs: Move CONFIG_UNICODE defguards into the code flow

[Gabriel Krisman Bertazi]

Instead of a bunch of ifdefs, make the unicode built checks part of the
code flow where possible, as requested by Torvalds.

Reviewed-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com>

---
Changes since v4:
  - Drop stub removal for !CONFIG_UNICODE case (eric)
---
 fs/f2fs/namei.c | 11 +++++------
 fs/f2fs/super.c |  8 ++++----
 2 files changed, 9 insertions(+), 10 deletions(-)

diff --git a/fs/f2fs/namei.c b/fs/f2fs/namei.c
index 5f213f05556d..8567a9045df1 100644
--- a/fs/f2fs/namei.c
+++ b/fs/f2fs/namei.c
@@ -561,8 +561,7 @@ static struct dentry *f2fs_lookup(struct inode *dir, struct dentry *dentry,
 		goto out_iput;
 	}
 out_splice:
-#if IS_ENABLED(CONFIG_UNICODE)
-	if (!inode && IS_CASEFOLDED(dir)) {
+	if (IS_ENABLED(CONFIG_UNICODE) && !inode && IS_CASEFOLDED(dir)) {
 		/* Eventually we want to call d_add_ci(dentry, NULL)
 		 * for negative dentries in the encoding case as
 		 * well.  For now, prevent the negative dentry
@@ -571,7 +570,7 @@ static struct dentry *f2fs_lookup(struct inode *dir, struct dentry *dentry,
 		trace_f2fs_lookup_end(dir, dentry, ino, err);
 		return NULL;
 	}
-#endif
+
 	new = d_splice_alias(inode, dentry);
 	err = PTR_ERR_OR_ZERO(new);
 	trace_f2fs_lookup_end(dir, dentry, ino, !new ? -ENOENT : err);
@@ -622,16 +621,16 @@ static int f2fs_unlink(struct inode *dir, struct dentry *dentry)
 		goto fail;
 	}
 	f2fs_delete_entry(de, page, dir, inode);
-#if IS_ENABLED(CONFIG_UNICODE)
+
 	/* VFS negative dentries are incompatible with Encoding and
 	 * Case-insensitiveness. Eventually we'll want avoid
 	 * invalidating the dentries here, alongside with returning the
 	 * negative dentries at f2fs_lookup(), when it is better
 	 * supported by the VFS for the CI case.
 	 */
-	if (IS_CASEFOLDED(dir))
+	if (IS_ENABLED(CONFIG_UNICODE) && IS_CASEFOLDED(dir))
 		d_invalidate(dentry);
-#endif
+
 	f2fs_unlock_op(sbi);
 
 	if (IS_DIRSYNC(dir))
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index baefd398ec1a..b17bd7a70d53 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -283,7 +283,7 @@ struct kmem_cache *f2fs_cf_name_slab;
 static int __init f2fs_create_casefold_cache(void)
 {
 	f2fs_cf_name_slab = f2fs_kmem_cache_create("f2fs_casefolded_name",
-							F2FS_NAME_LEN);
+						   F2FS_NAME_LEN);
 	if (!f2fs_cf_name_slab)
 		return -ENOMEM;
 	return 0;
@@ -1259,13 +1259,13 @@ static int parse_options(struct super_block *sb, char *options, bool is_remount)
 		return -EINVAL;
 	}
 #endif
-#if !IS_ENABLED(CONFIG_UNICODE)
-	if (f2fs_sb_has_casefold(sbi)) {
+
+	if (!IS_ENABLED(CONFIG_UNICODE) && f2fs_sb_has_casefold(sbi)) {
 		f2fs_err(sbi,
 			"Filesystem with casefold feature cannot be mounted without CONFIG_UNICODE");
 		return -EINVAL;
 	}
-#endif
+
 	/*
 	 * The BLKZONED feature indicates that the drive was formatted with
 	 * zone alignment optimization. This is optional for host-aware
-- 
2.36.1

Re: [PATCH v7 0/8] Clean up the case-insensitive lookup path

[Gabriel Krisman Bertazi]

Gabriel Krisman Bertazi <krisman@collabora.com> writes:

> Hi Eric, Ted,
>
> This is v7 of this series (thank you for the feedback!) .  This picks up
> a few r-b tags and has one small fix asked by Eric to handle a corner
> case in ext4_match when IS_ENCRYPTED() and the key is added during
> lookup.
>

Ugh, sorry. this is a bogus submission. please, disregard.

-- 
Gabriel Krisman Bertazi