f2fs: rework filename handling

Rework f2fs's handling of filenames to use a new 'struct f2fs_filename'.
Similar to 'struct ext4_filename', this stores the usr_fname, disk_name,
dirhash, crypto_buf, and casefolded name.  Some of these names can be
NULL in some cases.  'struct f2fs_filename' differs from
'struct fscrypt_name' mainly in that the casefolded name is included.

For user-initiated directory operations like lookup() and create(),
initialize the f2fs_filename by translating the corresponding
fscrypt_name, then computing the dirhash and casefolded name if needed.

This makes the dirhash and casefolded name be cached for each syscall,
so we don't have to recompute them repeatedly.  (Previously, f2fs
computed the dirhash once per directory level, and the casefolded name
once per directory block.)  This improves performance.

This rework also makes it much easier to correctly handle all
combinations of normal, encrypted, casefolded, and encrypted+casefolded
directories.  (The fourth isn't supported yet but is being worked on.)

The only other cases where an f2fs_filename gets initialized are for two
filesystem-internal operations: (1) when converting an inline directory
to a regular one, we grab the needed disk_name and hash from an existing
f2fs_dir_entry; and (2) when roll-forward recovering a new dentry, we
grab the needed disk_name from f2fs_inode::i_name and compute the hash.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

1 files changed, 174 insertions, 136 deletions

diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c
index 44eb12a00cd0..29f70f2295cc 100644
--- a/fs/f2fs/dir.c
+++ b/fs/f2fs/dir.c
@@ -70,6 +70,111 @@ unsigned char f2fs_get_de_type(struct f2fs_dir_entry *de)
 	return DT_UNKNOWN;
 }
 
+/* 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)
+{
+#ifdef CONFIG_UNICODE
+	struct f2fs_sb_info *sbi = F2FS_SB(dir->i_sb);
+
+	if (IS_CASEFOLDED(dir)) {
+		fname->cf_name.name = f2fs_kmalloc(sbi, F2FS_NAME_LEN,
+						   GFP_NOFS);
+		if (!fname->cf_name.name)
+			return -ENOMEM;
+		fname->cf_name.len = utf8_casefold(sbi->s_encoding,
+						   fname->usr_fname,
+						   fname->cf_name.name,
+						   F2FS_NAME_LEN);
+		if ((int)fname->cf_name.len <= 0) {
+			kfree(fname->cf_name.name);
+			fname->cf_name.name = NULL;
+			if (f2fs_has_strict_mode(sbi))
+				return -EINVAL;
+			/* fall back to treating name as opaque byte sequence */
+		}
+	}
+#endif
+	return 0;
+}
+
+static int __f2fs_setup_filename(const struct inode *dir,
+				 const struct fscrypt_name *crypt_name,
+				 struct f2fs_filename *fname)
+{
+	int err;
+
+	memset(fname, 0, sizeof(*fname));
+
+	fname->usr_fname = crypt_name->usr_fname;
+	fname->disk_name = crypt_name->disk_name;
+#ifdef CONFIG_FS_ENCRYPTION
+	fname->crypto_buf = crypt_name->crypto_buf;
+#endif
+	if (crypt_name->is_ciphertext_name) {
+		/* hash was decoded from the no-key name */
+		fname->hash = cpu_to_le32(crypt_name->hash);
+	} else {
+		err = f2fs_init_casefolded_name(dir, fname);
+		if (err) {
+			f2fs_free_filename(fname);
+			return err;
+		}
+		f2fs_hash_filename(dir, fname);
+	}
+	return 0;
+}
+
+/*
+ * Prepare to search for @iname in @dir.  This is similar to
+ * fscrypt_setup_filename(), but this also handles computing the casefolded name
+ * and the f2fs dirhash if needed, then packing all the information about this
+ * filename up into a 'struct f2fs_filename'.
+ */
+int f2fs_setup_filename(struct inode *dir, const struct qstr *iname,
+			int lookup, struct f2fs_filename *fname)
+{
+	struct fscrypt_name crypt_name;
+	int err;
+
+	err = fscrypt_setup_filename(dir, iname, lookup, &crypt_name);
+	if (err)
+		return err;
+
+	return __f2fs_setup_filename(dir, &crypt_name, fname);
+}
+
+/*
+ * Prepare to look up @dentry in @dir.  This is similar to
+ * fscrypt_prepare_lookup(), but this also handles computing the casefolded name
+ * and the f2fs dirhash if needed, then packing all the information about this
+ * filename up into a 'struct f2fs_filename'.
+ */
+int f2fs_prepare_lookup(struct inode *dir, struct dentry *dentry,
+			struct f2fs_filename *fname)
+{
+	struct fscrypt_name crypt_name;
+	int err;
+
+	err = fscrypt_prepare_lookup(dir, dentry, &crypt_name);
+	if (err)
+		return err;
+
+	return __f2fs_setup_filename(dir, &crypt_name, fname);
+}
+
+void f2fs_free_filename(struct f2fs_filename *fname)
+{
+#ifdef CONFIG_FS_ENCRYPTION
+	kfree(fname->crypto_buf.name);
+	fname->crypto_buf.name = NULL;
+#endif
+#ifdef CONFIG_UNICODE
+	kfree(fname->cf_name.name);
+	fname->cf_name.name = NULL;
+#endif
+}
+
 static unsigned long dir_block_index(unsigned int level,
 				int dir_level, unsigned int idx)
 {
@@ -84,8 +189,7 @@ static unsigned long dir_block_index(unsigned int level,
 
 static struct f2fs_dir_entry *find_in_block(struct inode *dir,
 				struct page *dentry_page,
-				struct fscrypt_name *fname,
-				f2fs_hash_t namehash,
+				const struct f2fs_filename *fname,
 				int *max_slots,
 				struct page **res_page)
 {
@@ -96,7 +200,7 @@ static struct f2fs_dir_entry *find_in_block(struct inode *dir,
 	dentry_blk = (struct f2fs_dentry_block *)page_address(dentry_page);
 
 	make_dentry_ptr_block(dir, &d, dentry_blk);
-	de = f2fs_find_target_dentry(fname, namehash, max_slots, &d);
+	de = f2fs_find_target_dentry(&d, fname, max_slots);
 	if (de)
 		*res_page = dentry_page;
 
@@ -109,102 +213,55 @@ static struct f2fs_dir_entry *find_in_block(struct inode *dir,
  * being searched for.
  */
 static bool f2fs_match_ci_name(const struct inode *dir, const struct qstr *name,
-			       const struct qstr *entry, bool quick)
+			       const u8 *de_name, u32 de_name_len)
 {
 	const struct f2fs_sb_info *sbi = F2FS_SB(dir->i_sb);
 	const struct unicode_map *um = sbi->s_encoding;
+	struct qstr entry = QSTR_INIT(de_name, de_name_len);
 	int res;
 
-	if (quick)
-		res = utf8_strncasecmp_folded(um, name, entry);
-	else
-		res = utf8_strncasecmp(um, name, entry);
+	res = utf8_strncasecmp_folded(um, name, &entry);
 	if (res < 0) {
 		/*
 		 * In strict mode, ignore invalid names.  In non-strict mode,
 		 * fall back to treating them as opaque byte sequences.
 		 */
-		if (f2fs_has_strict_mode(sbi) || name->len != entry->len)
+		if (f2fs_has_strict_mode(sbi) || name->len != entry.len)
 			return false;
-		return !memcmp(name->name, entry->name, name->len);
+		return !memcmp(name->name, entry.name, name->len);
 	}
 	return res == 0;
 }
+#endif /* CONFIG_UNICODE */
 
-static void f2fs_fname_setup_ci_filename(struct inode *dir,
-					const struct qstr *iname,
-					struct fscrypt_str *cf_name)
+static inline bool f2fs_match_name(const struct inode *dir,
+				   const struct f2fs_filename *fname,
+				   const u8 *de_name, u32 de_name_len)
 {
-	struct f2fs_sb_info *sbi = F2FS_I_SB(dir);
+	struct fscrypt_name f;
 
-	if (!IS_CASEFOLDED(dir)) {
-		cf_name->name = NULL;
-		return;
-	}
-
-	cf_name->name = f2fs_kmalloc(sbi, F2FS_NAME_LEN, GFP_NOFS);
-	if (!cf_name->name)
-		return;
-
-	cf_name->len = utf8_casefold(sbi->s_encoding,
-					iname, cf_name->name,
-					F2FS_NAME_LEN);
-	if ((int)cf_name->len <= 0) {
-		kvfree(cf_name->name);
-		cf_name->name = NULL;
-	}
-}
-#endif
-
-static inline bool f2fs_match_name(struct f2fs_dentry_ptr *d,
-					struct f2fs_dir_entry *de,
-					struct fscrypt_name *fname,
-					struct fscrypt_str *cf_str,
-					unsigned long bit_pos,
-					f2fs_hash_t namehash)
-{
 #ifdef CONFIG_UNICODE
-	struct inode *parent = d->inode;
-	struct f2fs_sb_info *sbi = F2FS_I_SB(parent);
-	struct qstr entry;
-#endif
+	if (fname->cf_name.name) {
+		struct qstr cf = FSTR_TO_QSTR(&fname->cf_name);
 
-	if (de->hash_code != namehash)
-		return false;
-
-#ifdef CONFIG_UNICODE
-	entry.name = d->filename[bit_pos];
-	entry.len = de->name_len;
-
-	if (sbi->s_encoding && IS_CASEFOLDED(parent)) {
-		if (cf_str->name) {
-			struct qstr cf = {.name = cf_str->name,
-					  .len = cf_str->len};
-			return f2fs_match_ci_name(parent, &cf, &entry, true);
-		}
-		return f2fs_match_ci_name(parent, fname->usr_fname, &entry,
-					  false);
+		return f2fs_match_ci_name(dir, &cf, de_name, de_name_len);
 	}
 #endif
-	if (fscrypt_match_name(fname, d->filename[bit_pos],
-				le16_to_cpu(de->name_len)))
-		return true;
-	return false;
+	f.usr_fname = fname->usr_fname;
+	f.disk_name = fname->disk_name;
+#ifdef CONFIG_FS_ENCRYPTION
+	f.crypto_buf = fname->crypto_buf;
+#endif
+	return fscrypt_match_name(&f, de_name, de_name_len);
 }
 
-struct f2fs_dir_entry *f2fs_find_target_dentry(struct fscrypt_name *fname,
-			f2fs_hash_t namehash, int *max_slots,
-			struct f2fs_dentry_ptr *d)
+struct f2fs_dir_entry *f2fs_find_target_dentry(const struct f2fs_dentry_ptr *d,
+			const struct f2fs_filename *fname, int *max_slots)
 {
 	struct f2fs_dir_entry *de;
-	struct fscrypt_str cf_str = { .name = NULL, .len = 0 };
 	unsigned long bit_pos = 0;
 	int max_len = 0;
 
-#ifdef CONFIG_UNICODE
-	f2fs_fname_setup_ci_filename(d->inode, fname->usr_fname, &cf_str);
-#endif
-
 	if (max_slots)
 		*max_slots = 0;
 	while (bit_pos < d->max) {
@@ -221,7 +278,9 @@ struct f2fs_dir_entry *f2fs_find_target_dentry(struct fscrypt_name *fname,
 			continue;
 		}
 
-		if (f2fs_match_name(d, de, fname, &cf_str, bit_pos, namehash))
+		if (de->hash_code == fname->hash &&
+		    f2fs_match_name(d->inode, fname, d->filename[bit_pos],
+				    le16_to_cpu(de->name_len)))
 			goto found;
 
 		if (max_slots && max_len > *max_slots)
@@ -235,33 +294,27 @@ struct f2fs_dir_entry *f2fs_find_target_dentry(struct fscrypt_name *fname,
 found:
 	if (max_slots && max_len > *max_slots)
 		*max_slots = max_len;
-
-#ifdef CONFIG_UNICODE
-	kvfree(cf_str.name);
-#endif
 	return de;
 }
 
 static struct f2fs_dir_entry *find_in_level(struct inode *dir,
 					unsigned int level,
-					struct fscrypt_name *fname,
+					const struct f2fs_filename *fname,
 					struct page **res_page)
 {
-	struct qstr name = FSTR_TO_QSTR(&fname->disk_name);
-	int s = GET_DENTRY_SLOTS(name.len);
+	int s = GET_DENTRY_SLOTS(fname->disk_name.len);
 	unsigned int nbucket, nblock;
 	unsigned int bidx, end_block;
 	struct page *dentry_page;
 	struct f2fs_dir_entry *de = NULL;
 	bool room = false;
 	int max_slots;
-	f2fs_hash_t namehash = f2fs_dentry_hash(dir, &name, fname);
 
 	nbucket = dir_buckets(level, F2FS_I(dir)->i_dir_level);
 	nblock = bucket_blocks(level);
 
 	bidx = dir_block_index(level, F2FS_I(dir)->i_dir_level,
-					le32_to_cpu(namehash) % nbucket);
+			       le32_to_cpu(fname->hash) % nbucket);
 	end_block = bidx + nblock;
 
 	for (; bidx < end_block; bidx++) {
@@ -277,8 +330,8 @@ static struct f2fs_dir_entry *find_in_level(struct inode *dir,
 			}
 		}
 
-		de = find_in_block(dir, dentry_page, fname, namehash,
-							&max_slots, res_page);
+		de = find_in_block(dir, dentry_page, fname, &max_slots,
+				   res_page);
 		if (de)
 			break;
 
@@ -287,8 +340,8 @@ static struct f2fs_dir_entry *find_in_level(struct inode *dir,
 		f2fs_put_page(dentry_page, 0);
 	}
 
-	if (!de && room && F2FS_I(dir)->chash != namehash) {
-		F2FS_I(dir)->chash = namehash;
+	if (!de && room && F2FS_I(dir)->chash != fname->hash) {
+		F2FS_I(dir)->chash = fname->hash;
 		F2FS_I(dir)->clevel = level;
 	}
 
@@ -296,7 +349,8 @@ static struct f2fs_dir_entry *find_in_level(struct inode *dir,
 }
 
 struct f2fs_dir_entry *__f2fs_find_entry(struct inode *dir,
-			struct fscrypt_name *fname, struct page **res_page)
+					 const struct f2fs_filename *fname,
+					 struct page **res_page)
 {
 	unsigned long npages = dir_blocks(dir);
 	struct f2fs_dir_entry *de = NULL;
@@ -345,18 +399,10 @@ struct f2fs_dir_entry *f2fs_find_entry(struct inode *dir,
 			const struct qstr *child, struct page **res_page)
 {
 	struct f2fs_dir_entry *de = NULL;
-	struct fscrypt_name fname;
+	struct f2fs_filename fname;
 	int err;
 
-#ifdef CONFIG_UNICODE
-	if (f2fs_has_strict_mode(F2FS_I_SB(dir)) && IS_CASEFOLDED(dir) &&
-			utf8_validate(F2FS_I_SB(dir)->s_encoding, child)) {
-		*res_page = ERR_PTR(-EINVAL);
-		return NULL;
-	}
-#endif
-
-	err = fscrypt_setup_filename(dir, child, 1, &fname);
+	err = f2fs_setup_filename(dir, child, 1, &fname);
 	if (err) {
 		if (err == -ENOENT)
 			*res_page = NULL;
@@ -367,7 +413,7 @@ struct f2fs_dir_entry *f2fs_find_entry(struct inode *dir,
 
 	de = __f2fs_find_entry(dir, &fname, res_page);
 
-	fscrypt_free_filename(&fname);
+	f2fs_free_filename(&fname);
 	return de;
 }
 
@@ -408,7 +454,8 @@ void f2fs_set_link(struct inode *dir, struct f2fs_dir_entry *de,
 	f2fs_put_page(page, 1);
 }
 
-static void init_dent_inode(const struct qstr *name, struct page *ipage)
+static void init_dent_inode(const struct f2fs_filename *fname,
+			    struct page *ipage)
 {
 	struct f2fs_inode *ri;
 
@@ -416,16 +463,16 @@ static void init_dent_inode(const struct qstr *name, struct page *ipage)
 
 	/* copy name info. to this inode page */
 	ri = F2FS_INODE(ipage);
-	ri->i_namelen = cpu_to_le32(name->len);
-	memcpy(ri->i_name, name->name, name->len);
+	ri->i_namelen = cpu_to_le32(fname->disk_name.len);
+	memcpy(ri->i_name, fname->disk_name.name, fname->disk_name.len);
 	set_page_dirty(ipage);
 }
 
 void f2fs_do_make_empty_dir(struct inode *inode, struct inode *parent,
 					struct f2fs_dentry_ptr *d)
 {
-	struct qstr dot = QSTR_INIT(".", 1);
-	struct qstr dotdot = QSTR_INIT("..", 2);
+	struct fscrypt_str dot = FSTR_INIT(".", 1);
+	struct fscrypt_str dotdot = FSTR_INIT("..", 2);
 
 	/* update dirent of "." */
 	f2fs_update_dentry(inode->i_ino, inode->i_mode, d, &dot, 0, 0);
@@ -459,8 +506,7 @@ static int make_empty_dir(struct inode *inode,
 }
 
 struct page *f2fs_init_inode_metadata(struct inode *inode, struct inode *dir,
-			const struct qstr *new_name, const struct qstr *orig_name,
-			struct page *dpage)
+			const struct f2fs_filename *fname, struct page *dpage)
 {
 	struct page *page;
 	int err;
@@ -485,7 +531,8 @@ struct page *f2fs_init_inode_metadata(struct inode *inode, struct inode *dir,
 		if (err)
 			goto put_error;
 
-		err = f2fs_init_security(inode, dir, orig_name, page);
+		err = f2fs_init_security(inode, dir,
+					 fname ? fname->usr_fname : NULL, page);
 		if (err)
 			goto put_error;
 
@@ -500,8 +547,8 @@ struct page *f2fs_init_inode_metadata(struct inode *inode, struct inode *dir,
 			return page;
 	}
 
-	if (new_name) {
-		init_dent_inode(new_name, page);
+	if (fname) {
+		init_dent_inode(fname, page);
 		if (IS_ENCRYPTED(dir))
 			file_set_enc_name(inode);
 	}
@@ -569,11 +616,11 @@ next:
 }
 
 bool f2fs_has_enough_room(struct inode *dir, struct page *ipage,
-					struct fscrypt_name *fname)
+			  const struct f2fs_filename *fname)
 {
 	struct f2fs_dentry_ptr d;
 	unsigned int bit_pos;
-	int slots = GET_DENTRY_SLOTS(fname_len(fname));
+	int slots = GET_DENTRY_SLOTS(fname->disk_name.len);
 
 	make_dentry_ptr_inline(dir, &d, inline_data_addr(dir, ipage));
 
@@ -583,8 +630,8 @@ bool f2fs_has_enough_room(struct inode *dir, struct page *ipage,
 }
 
 void f2fs_update_dentry(nid_t ino, umode_t mode, struct f2fs_dentry_ptr *d,
-				const struct qstr *name, f2fs_hash_t name_hash,
-				unsigned int bit_pos)
+			const struct fscrypt_str *name, f2fs_hash_t name_hash,
+			unsigned int bit_pos)
 {
 	struct f2fs_dir_entry *de;
 	int slots = GET_DENTRY_SLOTS(name->len);
@@ -604,15 +651,13 @@ void f2fs_update_dentry(nid_t ino, umode_t mode, struct f2fs_dentry_ptr *d,
 	}
 }
 
-int f2fs_add_regular_entry(struct inode *dir, const struct qstr *new_name,
-				const struct qstr *orig_name,
-				struct inode *inode, nid_t ino, umode_t mode)
+int f2fs_add_regular_entry(struct inode *dir, const struct f2fs_filename *fname,
+			   struct inode *inode, nid_t ino, umode_t mode)
 {
 	unsigned int bit_pos;
 	unsigned int level;
 	unsigned int current_depth;
 	unsigned long bidx, block;
-	f2fs_hash_t dentry_hash;
 	unsigned int nbucket, nblock;
 	struct page *dentry_page = NULL;
 	struct f2fs_dentry_block *dentry_blk = NULL;
@@ -621,11 +666,10 @@ int f2fs_add_regular_entry(struct inode *dir, const struct qstr *new_name,
 	int slots, err = 0;
 
 	level = 0;
-	slots = GET_DENTRY_SLOTS(new_name->len);
-	dentry_hash = f2fs_dentry_hash(dir, new_name, NULL);
+	slots = GET_DENTRY_SLOTS(fname->disk_name.len);
 
 	current_depth = F2FS_I(dir)->i_current_depth;
-	if (F2FS_I(dir)->chash == dentry_hash) {
+	if (F2FS_I(dir)->chash == fname->hash) {
 		level = F2FS_I(dir)->clevel;
 		F2FS_I(dir)->chash = 0;
 	}
@@ -647,7 +691,7 @@ start:
 	nblock = bucket_blocks(level);
 
 	bidx = dir_block_index(level, F2FS_I(dir)->i_dir_level,
-				(le32_to_cpu(dentry_hash) % nbucket));
+				(le32_to_cpu(fname->hash) % nbucket));
 
 	for (block = bidx; block <= (bidx + nblock - 1); block++) {
 		dentry_page = f2fs_get_new_data_page(dir, NULL, block, true);
@@ -671,8 +715,7 @@ add_dentry:
 
 	if (inode) {
 		down_write(&F2FS_I(inode)->i_sem);
-		page = f2fs_init_inode_metadata(inode, dir, new_name,
-						orig_name, NULL);
+		page = f2fs_init_inode_metadata(inode, dir, fname, NULL);
 		if (IS_ERR(page)) {
 			err = PTR_ERR(page);
 			goto fail;
@@ -680,7 +723,8 @@ add_dentry:
 	}
 
 	make_dentry_ptr_block(NULL, &d, dentry_blk);
-	f2fs_update_dentry(ino, mode, &d, new_name, dentry_hash, bit_pos);
+	f2fs_update_dentry(ino, mode, &d, &fname->disk_name, fname->hash,
+			   bit_pos);
 
 	set_page_dirty(dentry_page);
 
@@ -704,21 +748,15 @@ fail:
 	return err;
 }
 
-int f2fs_add_dentry(struct inode *dir, struct fscrypt_name *fname,
-				struct inode *inode, nid_t ino, umode_t mode)
+int f2fs_add_dentry(struct inode *dir, const struct f2fs_filename *fname,
+		    struct inode *inode, nid_t ino, umode_t mode)
 {
-	struct qstr new_name;
 	int err = -EAGAIN;
 
-	new_name.name = fname_name(fname);
-	new_name.len = fname_len(fname);
-
 	if (f2fs_has_inline_dentry(dir))
-		err = f2fs_add_inline_entry(dir, &new_name, fname->usr_fname,
-							inode, ino, mode);
+		err = f2fs_add_inline_entry(dir, fname, inode, ino, mode);
 	if (err == -EAGAIN)
-		err = f2fs_add_regular_entry(dir, &new_name, fname->usr_fname,
-							inode, ino, mode);
+		err = f2fs_add_regular_entry(dir, fname, inode, ino, mode);
 
 	f2fs_update_time(F2FS_I_SB(dir), REQ_TIME);
 	return err;
@@ -731,12 +769,12 @@ int f2fs_add_dentry(struct inode *dir, struct fscrypt_name *fname,
 int f2fs_do_add_link(struct inode *dir, const struct qstr *name,
 				struct inode *inode, nid_t ino, umode_t mode)
 {
-	struct fscrypt_name fname;
+	struct f2fs_filename fname;
 	struct page *page = NULL;
 	struct f2fs_dir_entry *de = NULL;
 	int err;
 
-	err = fscrypt_setup_filename(dir, name, 0, &fname);
+	err = f2fs_setup_filename(dir, name, 0, &fname);
 	if (err)
 		return err;
 
@@ -759,7 +797,7 @@ int f2fs_do_add_link(struct inode *dir, const struct qstr *name,
 	} else {
 		err = f2fs_add_dentry(dir, &fname, inode, ino, mode);
 	}
-	fscrypt_free_filename(&fname);
+	f2fs_free_filename(&fname);
 	return err;
 }
 
@@ -769,7 +807,7 @@ int f2fs_do_tmpfile(struct inode *inode, struct inode *dir)
 	int err = 0;
 
 	down_write(&F2FS_I(inode)->i_sem);
-	page = f2fs_init_inode_metadata(inode, dir, NULL, NULL, NULL);
+	page = f2fs_init_inode_metadata(inode, dir, NULL, NULL);
 	if (IS_ERR(page)) {
 		err = PTR_ERR(page);
 		goto fail;