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, 22 insertions, 23 deletions

diff --git a/fs/f2fs/inline.c b/fs/f2fs/inline.c
index 59a4b7ff11e1..751a012ff840 100644
--- a/fs/f2fs/inline.c
+++ b/fs/f2fs/inline.c
@@ -305,15 +305,14 @@ process_inline:
 }
 
 struct f2fs_dir_entry *f2fs_find_in_inline_dir(struct inode *dir,
-			struct fscrypt_name *fname, struct page **res_page)
+					const struct f2fs_filename *fname,
+					struct page **res_page)
 {
 	struct f2fs_sb_info *sbi = F2FS_SB(dir->i_sb);
-	struct qstr name = FSTR_TO_QSTR(&fname->disk_name);
 	struct f2fs_dir_entry *de;
 	struct f2fs_dentry_ptr d;
 	struct page *ipage;
 	void *inline_dentry;
-	f2fs_hash_t namehash;
 
 	ipage = f2fs_get_node_page(sbi, dir->i_ino);
 	if (IS_ERR(ipage)) {
@@ -321,12 +320,10 @@ struct f2fs_dir_entry *f2fs_find_in_inline_dir(struct inode *dir,
 		return NULL;
 	}
 
-	namehash = f2fs_dentry_hash(dir, &name, fname);
-
 	inline_dentry = inline_data_addr(dir, ipage);
 
 	make_dentry_ptr_inline(dir, &d, inline_dentry);
-	de = f2fs_find_target_dentry(fname, namehash, NULL, &d);
+	de = f2fs_find_target_dentry(&d, fname, NULL);
 	unlock_page(ipage);
 	if (de)
 		*res_page = ipage;
@@ -443,7 +440,7 @@ static int f2fs_add_inline_entries(struct inode *dir, void *inline_dentry)
 
 	while (bit_pos < d.max) {
 		struct f2fs_dir_entry *de;
-		struct qstr new_name;
+		struct f2fs_filename fname;
 		nid_t ino;
 		umode_t fake_mode;
 
@@ -459,14 +456,19 @@ static int f2fs_add_inline_entries(struct inode *dir, void *inline_dentry)
 			continue;
 		}
 
-		new_name.name = d.filename[bit_pos];
-		new_name.len = le16_to_cpu(de->name_len);
+		/*
+		 * We only need the disk_name and hash to move the dentry.
+		 * We don't need the original or casefolded filenames.
+		 */
+		memset(&fname, 0, sizeof(fname));
+		fname.disk_name.name = d.filename[bit_pos];
+		fname.disk_name.len = le16_to_cpu(de->name_len);
+		fname.hash = de->hash_code;
 
 		ino = le32_to_cpu(de->ino);
 		fake_mode = f2fs_get_de_type(de) << S_SHIFT;
 
-		err = f2fs_add_regular_entry(dir, &new_name, NULL, NULL,
-							ino, fake_mode);
+		err = f2fs_add_regular_entry(dir, &fname, NULL, ino, fake_mode);
 		if (err)
 			goto punch_dentry_pages;
 
@@ -543,7 +545,7 @@ int f2fs_try_convert_inline_dir(struct inode *dir, struct dentry *dentry)
 {
 	struct f2fs_sb_info *sbi = F2FS_I_SB(dir);
 	struct page *ipage;
-	struct fscrypt_name fname;
+	struct f2fs_filename fname;
 	void *inline_dentry = NULL;
 	int err = 0;
 
@@ -552,7 +554,7 @@ int f2fs_try_convert_inline_dir(struct inode *dir, struct dentry *dentry)
 
 	f2fs_lock_op(sbi);
 
-	err = fscrypt_setup_filename(dir, &dentry->d_name, 0, &fname);
+	err = f2fs_setup_filename(dir, &dentry->d_name, 0, &fname);
 	if (err)
 		goto out;
 
@@ -573,23 +575,21 @@ int f2fs_try_convert_inline_dir(struct inode *dir, struct dentry *dentry)
 	if (!err)
 		f2fs_put_page(ipage, 1);
 out_fname:
-	fscrypt_free_filename(&fname);
+	f2fs_free_filename(&fname);
 out:
 	f2fs_unlock_op(sbi);
 	return err;
 }
 
-int f2fs_add_inline_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_inline_entry(struct inode *dir, const struct f2fs_filename *fname,
+			  struct inode *inode, nid_t ino, umode_t mode)
 {
 	struct f2fs_sb_info *sbi = F2FS_I_SB(dir);
 	struct page *ipage;
 	unsigned int bit_pos;
-	f2fs_hash_t name_hash;
 	void *inline_dentry = NULL;
 	struct f2fs_dentry_ptr d;
-	int slots = GET_DENTRY_SLOTS(new_name->len);
+	int slots = GET_DENTRY_SLOTS(fname->disk_name.len);
 	struct page *page = NULL;
 	int err = 0;
 
@@ -611,8 +611,7 @@ int f2fs_add_inline_entry(struct inode *dir, const struct qstr *new_name,
 
 	if (inode) {
 		down_write(&F2FS_I(inode)->i_sem);
-		page = f2fs_init_inode_metadata(inode, dir, new_name,
-						orig_name, ipage);
+		page = f2fs_init_inode_metadata(inode, dir, fname, ipage);
 		if (IS_ERR(page)) {
 			err = PTR_ERR(page);
 			goto fail;
@@ -621,8 +620,8 @@ int f2fs_add_inline_entry(struct inode *dir, const struct qstr *new_name,
 
 	f2fs_wait_on_page_writeback(ipage, NODE, true, true);
 
-	name_hash = f2fs_dentry_hash(dir, new_name, NULL);
-	f2fs_update_dentry(ino, mode, &d, new_name, name_hash, bit_pos);
+	f2fs_update_dentry(ino, mode, &d, &fname->disk_name, fname->hash,
+			   bit_pos);
 
 	set_page_dirty(ipage);