text: // SPDX-License-Identifier: GPL-2.0
  /*
   * fs/f2fs/dir.c
   *
   * Copyright (c) 2012 Samsung Electronics Co., Ltd.
   *             http://www.samsung.com/
   */
  #include <linux/fs.h>
  #include <linux/f2fs_fs.h>
  #include <linux/sched/signal.h>
  #include <linux/unicode.h>
  #include "f2fs.h"
  #include "node.h"
  #include "acl.h"
  #include "xattr.h"
  #include <trace/events/f2fs.h>
  
  static unsigned long dir_blocks(struct inode *inode)
  {
  	return ((unsigned long long) (i_size_read(inode) + PAGE_SIZE - 1))
  							>> PAGE_SHIFT;
  }
  
  static unsigned int dir_buckets(unsigned int level, int dir_level)
  {
  	if (level + dir_level < MAX_DIR_HASH_DEPTH / 2)
  		return 1 << (level + dir_level);
  	else
  		return MAX_DIR_BUCKETS;
  }
  
  static unsigned int bucket_blocks(unsigned int level)
  {
  	if (level < MAX_DIR_HASH_DEPTH / 2)
  		return 2;
  	else
  		return 4;
  }
  
  static unsigned char f2fs_filetype_table[F2FS_FT_MAX] = {
  	[F2FS_FT_UNKNOWN]	= DT_UNKNOWN,
  	[F2FS_FT_REG_FILE]	= DT_REG,
  	[F2FS_FT_DIR]		= DT_DIR,
  	[F2FS_FT_CHRDEV]	= DT_CHR,
  	[F2FS_FT_BLKDEV]	= DT_BLK,
  	[F2FS_FT_FIFO]		= DT_FIFO,
  	[F2FS_FT_SOCK]		= DT_SOCK,
  	[F2FS_FT_SYMLINK]	= DT_LNK,
  };
  
  static unsigned char f2fs_type_by_mode[S_IFMT >> S_SHIFT] = {
  	[S_IFREG >> S_SHIFT]	= F2FS_FT_REG_FILE,
  	[S_IFDIR >> S_SHIFT]	= F2FS_FT_DIR,
  	[S_IFCHR >> S_SHIFT]	= F2FS_FT_CHRDEV,
  	[S_IFBLK >> S_SHIFT]	= F2FS_FT_BLKDEV,
  	[S_IFIFO >> S_SHIFT]	= F2FS_FT_FIFO,
  	[S_IFSOCK >> S_SHIFT]	= F2FS_FT_SOCK,
  	[S_IFLNK >> S_SHIFT]	= F2FS_FT_SYMLINK,
  };
  
  static void set_de_type(struct f2fs_dir_entry *de, umode_t mode)
  {
  	de->file_type = f2fs_type_by_mode[(mode & S_IFMT) >> S_SHIFT];
  }
  
  unsigned char f2fs_get_de_type(struct f2fs_dir_entry *de)
  {
  	if (de->file_type < F2FS_FT_MAX)
  		return f2fs_filetype_table[de->file_type];
  	return DT_UNKNOWN;
  }
  
  static unsigned long dir_block_index(unsigned int level,
  				int dir_level, unsigned int idx)
  {
  	unsigned long i;
  	unsigned long bidx = 0;
  
  	for (i = 0; i < level; i++)
  		bidx += dir_buckets(i, dir_level) * bucket_blocks(i);
  	bidx += idx * bucket_blocks(level);
  	return bidx;
  }
  
  static struct f2fs_dir_entry *find_in_block(struct inode *dir,
  				struct page *dentry_page,
  				struct fscrypt_name *fname,
  				f2fs_hash_t namehash,
  				int *max_slots,
  				struct page **res_page)
  {
  	struct f2fs_dentry_block *dentry_blk;
  	struct f2fs_dir_entry *de;
  	struct f2fs_dentry_ptr d;
  
  	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);
  	if (de)
  		*res_page = dentry_page;
  
  	return de;
  }
  
  #ifdef CONFIG_UNICODE
  /*
   * Test whether a case-insensitive directory entry matches the filename
   * being searched for.
   *
   * Returns: 0 if the directory entry matches, more than 0 if it
   * doesn't match or less than zero on error.
   */
  int f2fs_ci_compare(const struct inode *parent, const struct qstr *name,
  				const struct qstr *entry, bool quick)
  {
  	const struct f2fs_sb_info *sbi = F2FS_SB(parent->i_sb);
  	const struct unicode_map *um = sbi->s_encoding;
  	int ret;
  
  	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 (f2fs_has_strict_mode(sbi))
  			return -EINVAL;
  
  		if (name->len != entry->len)
  			return 1;
  
  		return !!memcmp(name->name, entry->name, name->len);
  	}
  
  	return ret;
  }
  
  static void f2fs_fname_setup_ci_filename(struct inode *dir,
  					const struct qstr *iname,
  					struct fscrypt_str *cf_name)
  {
  	struct f2fs_sb_info *sbi = F2FS_I_SB(dir);
  
  	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 (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_ci_compare(parent, &cf, &entry, true);
  		}
  		return !f2fs_ci_compare(parent, fname->usr_fname, &entry,
  					false);
  	}
  #endif
  	if (fscrypt_match_name(fname, d->filename[bit_pos],
  				le16_to_cpu(de->name_len)))
  		return true;
  	return false;
  }
  
  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 *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) {
  		if (!test_bit_le(bit_pos, d->bitmap)) {
  			bit_pos++;
  			max_len++;
  			continue;
  		}
  
  		de = &d->dentry[bit_pos];
  
  		if (unlikely(!de->name_len)) {
  			bit_pos++;
  			continue;
  		}
  
  		if (f2fs_match_name(d, de, fname, &cf_str, bit_pos, namehash))
  			goto found;
  
  		if (max_slots && max_len > *max_slots)
  			*max_slots = max_len;
  		max_len = 0;
  
  		bit_pos += GET_DENTRY_SLOTS(le16_to_cpu(de->name_len));
  	}
  
  	de = NULL;
  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,
  					struct page **res_page)
  {
  	struct qstr name = FSTR_TO_QSTR(&fname->disk_name);
  	int s = GET_DENTRY_SLOTS(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);
  	end_block = bidx + nblock;
  
  	for (; bidx < end_block; bidx++) {
  		/* no need to allocate new dentry pages to all the indices */
  		dentry_page = f2fs_find_data_page(dir, bidx);
  		if (IS_ERR(dentry_page)) {
  			if (PTR_ERR(dentry_page) == -ENOENT) {
  				room = true;
  				continue;
  			} else {
  				*res_page = dentry_page;
  				break;
  			}
  		}
  
  		de = find_in_block(dir, dentry_page, fname, namehash,
  							&max_slots, res_page);
  		if (de)
  			break;
  
  		if (max_slots >= s)
  			room = true;
  		f2fs_put_page(dentry_page, 0);
  	}
  
  	if (!de && room && F2FS_I(dir)->chash != namehash) {
  		F2FS_I(dir)->chash = namehash;
  		F2FS_I(dir)->clevel = level;
  	}
  
  	return de;
  }
  
  struct f2fs_dir_entry *__f2fs_find_entry(struct inode *dir,
  			struct fscrypt_name *fname, struct page **res_page)
  {
  	unsigned long npages = dir_blocks(dir);
  	struct f2fs_dir_entry *de = NULL;
  	unsigned int max_depth;
  	unsigned int level;
  
  	if (f2fs_has_inline_dentry(dir)) {
  		*res_page = NULL;
  		de = f2fs_find_in_inline_dir(dir, fname, res_page);
  		goto out;
  	}
  
  	if (npages == 0) {
  		*res_page = NULL;
  		goto out;
  	}
  
  	max_depth = F2FS_I(dir)->i_current_depth;
  	if (unlikely(max_depth > MAX_DIR_HASH_DEPTH)) {
  		f2fs_warn(F2FS_I_SB(dir), "Corrupted max_depth of %lu: %u",
  			  dir->i_ino, max_depth);
  		max_depth = MAX_DIR_HASH_DEPTH;
  		f2fs_i_depth_write(dir, max_depth);
  	}
  
  	for (level = 0; level < max_depth; level++) {
  		*res_page = NULL;
  		de = find_in_level(dir, level, fname, res_page);
  		if (de || IS_ERR(*res_page))
  			break;
  	}
  out:
  	/* This is to increase the speed of f2fs_create */
  	if (!de)
  		F2FS_I(dir)->task = current;
  	return de;
  }
  
  /*
   * Find an entry in the specified directory with the wanted name.
   * It returns the page where the entry was found (as a parameter - res_page),
   * and the entry itself. Page is returned mapped and unlocked.
   * Entry is guaranteed to be valid.
   */
  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;
  	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);
  	if (err) {
  		if (err == -ENOENT)
  			*res_page = NULL;
  		else
  			*res_page = ERR_PTR(err);
  		return NULL;
  	}
  
  	de = __f2fs_find_entry(dir, &fname, res_page);
  
  	fscrypt_free_filename(&fname);
  	return de;
  }
  
  struct f2fs_dir_entry *f2fs_parent_dir(struct inode *dir, struct page **p)
  {
  	struct qstr dotdot = QSTR_INIT("..", 2);
  
  	return f2fs_find_entry(dir, &dotdot, p);
  }
  
  ino_t f2fs_inode_by_name(struct inode *dir, const struct qstr *qstr,
  							struct page **page)
  {
  	ino_t res = 0;
  	struct f2fs_dir_entry *de;
  
  	de = f2fs_find_entry(dir, qstr, page);
  	if (de) {
  		res = le32_to_cpu(de->ino);
  		f2fs_put_page(*page, 0);
  	}
  
  	return res;
  }
  
  void f2fs_set_link(struct inode *dir, struct f2fs_dir_entry *de,
  		struct page *page, struct inode *inode)
  {
  	enum page_type type = f2fs_has_inline_dentry(dir) ? NODE : DATA;
  	lock_page(page);
  	f2fs_wait_on_page_writeback(page, type, true, true);
  	de->ino = cpu_to_le32(inode->i_ino);
  	set_de_type(de, inode->i_mode);
  	set_page_dirty(page);
  
  	dir->i_mtime = dir->i_ctime = current_time(dir);
  	f2fs_mark_inode_dirty_sync(dir, false);
  	f2fs_put_page(page, 1);
  }
  
  static void init_dent_inode(const struct qstr *name, struct page *ipage)
  {
  	struct f2fs_inode *ri;
  
  	f2fs_wait_on_page_writeback(ipage, NODE, true, true);
  
  	/* 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);
  	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);
  
  	/* update dirent of "." */
  	f2fs_update_dentry(inode->i_ino, inode->i_mode, d, &dot, 0, 0);
  
  	/* update dirent of ".." */
  	f2fs_update_dentry(parent->i_ino, parent->i_mode, d, &dotdot, 0, 1);
  }
  
  static int make_empty_dir(struct inode *inode,
  		struct inode *parent, struct page *page)
  {
  	struct page *dentry_page;
  	struct f2fs_dentry_block *dentry_blk;
  	struct f2fs_dentry_ptr d;
  
  	if (f2fs_has_inline_dentry(inode))
  		return f2fs_make_empty_inline_dir(inode, parent, page);
  
  	dentry_page = f2fs_get_new_data_page(inode, page, 0, true);
  	if (IS_ERR(dentry_page))
  		return PTR_ERR(dentry_page);
  
  	dentry_blk = page_address(dentry_page);
  
  	make_dentry_ptr_block(NULL, &d, dentry_blk);
  	f2fs_do_make_empty_dir(inode, parent, &d);
  
  	set_page_dirty(dentry_page);
  	f2fs_put_page(dentry_page, 1);
  	return 0;
  }
  
  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)
  {
  	struct page *page;
  	int err;
  
  	if (is_inode_flag_set(inode, FI_NEW_INODE)) {
  		page = f2fs_new_inode_page(inode);
  		if (IS_ERR(page))
  			return page;
  
  		if (S_ISDIR(inode->i_mode)) {
  			/* in order to handle error case */
  			get_page(page);
  			err = make_empty_dir(inode, dir, page);
  			if (err) {
  				lock_page(page);
  				goto put_error;
  			}
  			put_page(page);
  		}
  
  		err = f2fs_init_acl(inode, dir, page, dpage);
  		if (err)
  			goto put_error;
  
  		err = f2fs_init_security(inode, dir, orig_name, page);
  		if (err)
  			goto put_error;
  
  		if (IS_ENCRYPTED(inode)) {
  			err = fscrypt_inherit_context(dir, inode, page, false);
  			if (err)
  				goto put_error;
  		}
  	} else {
  		page = f2fs_get_node_page(F2FS_I_SB(dir), inode->i_ino);
  		if (IS_ERR(page))
  			return page;
  	}
  
  	if (new_name) {
  		init_dent_inode(new_name, page);
  		if (IS_ENCRYPTED(dir))
  			file_set_enc_name(inode);
  	}
  
  	/*
  	 * This file should be checkpointed during fsync.
  	 * We lost i_pino from now on.
  	 */
  	if (is_inode_flag_set(inode, FI_INC_LINK)) {
  		if (!S_ISDIR(inode->i_mode))
  			file_lost_pino(inode);
  		/*
  		 * If link the tmpfile to alias through linkat path,
  		 * we should remove this inode from orphan list.
  		 */
  		if (inode->i_nlink == 0)
  			f2fs_remove_orphan_inode(F2FS_I_SB(dir), inode->i_ino);
  		f2fs_i_links_write(inode, true);
  	}
  	return page;
  
  put_error:
  	clear_nlink(inode);
  	f2fs_update_inode(inode, page);
  	f2fs_put_page(page, 1);
  	return ERR_PTR(err);
  }
  
  void f2fs_update_parent_metadata(struct inode *dir, struct inode *inode,
  						unsigned int current_depth)
  {
  	if (inode && is_inode_flag_set(inode, FI_NEW_INODE)) {
  		if (S_ISDIR(inode->i_mode))
  			f2fs_i_links_write(dir, true);
  		clear_inode_flag(inode, FI_NEW_INODE);
  	}
  	dir->i_mtime = dir->i_ctime = current_time(dir);
  	f2fs_mark_inode_dirty_sync(dir, false);
  
  	if (F2FS_I(dir)->i_current_depth != current_depth)
  		f2fs_i_depth_write(dir, current_depth);
  
  	if (inode && is_inode_flag_set(inode, FI_INC_LINK))
  		clear_inode_flag(inode, FI_INC_LINK);
  }
  
  int f2fs_room_for_filename(const void *bitmap, int slots, int max_slots)
  {
  	int bit_start = 0;
  	int zero_start, zero_end;
  next:
  	zero_start = find_next_zero_bit_le(bitmap, max_slots, bit_start);
  	if (zero_start >= max_slots)
  		return max_slots;
  
  	zero_end = find_next_bit_le(bitmap, max_slots, zero_start);
  	if (zero_end - zero_start >= slots)
  		return zero_start;
  
  	bit_start = zero_end + 1;
  
  	if (zero_end + 1 >= max_slots)
  		return max_slots;
  	goto next;
  }
  
  bool f2fs_has_enough_room(struct inode *dir, struct page *ipage,
  					struct fscrypt_name *fname)
  {
  	struct f2fs_dentry_ptr d;
  	unsigned int bit_pos;
  	int slots = GET_DENTRY_SLOTS(fname_len(fname));
  
  	make_dentry_ptr_inline(dir, &d, inline_data_addr(dir, ipage));
  
  	bit_pos = f2fs_room_for_filename(d.bitmap, slots, d.max);
  
  	return bit_pos < d.max;
  }
  
  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)
  {
  	struct f2fs_dir_entry *de;
  	int slots = GET_DENTRY_SLOTS(name->len);
  	int i;
  
  	de = &d->dentry[bit_pos];
  	de->hash_code = name_hash;
  	de->name_len = cpu_to_le16(name->len);
  	memcpy(d->filename[bit_pos], name->name, name->len);
  	de->ino = cpu_to_le32(ino);
  	set_de_type(de, mode);
  	for (i = 0; i < slots; i++) {
  		__set_bit_le(bit_pos + i, (void *)d->bitmap);
  		/* avoid wrong garbage data for readdir */
  		if (i)
  			(de + i)->name_len = 0;
  	}
  }
  
  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)
  {
  	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;
  	struct f2fs_dentry_ptr d;
  	struct page *page = NULL;
  	int slots, err = 0;
  
  	level = 0;
  	slots = GET_DENTRY_SLOTS(new_name->len);
  	dentry_hash = f2fs_dentry_hash(dir, new_name, NULL);
  
  	current_depth = F2FS_I(dir)->i_current_depth;
  	if (F2FS_I(dir)->chash == dentry_hash) {
  		level = F2FS_I(dir)->clevel;
  		F2FS_I(dir)->chash = 0;
  	}
  
  start:
  	if (time_to_inject(F2FS_I_SB(dir), FAULT_DIR_DEPTH)) {
  		f2fs_show_injection_info(F2FS_I_SB(dir), FAULT_DIR_DEPTH);
  		return -ENOSPC;
  	}
  
  	if (unlikely(current_depth == MAX_DIR_HASH_DEPTH))
  		return -ENOSPC;
  
  	/* Increase the depth, if required */
  	if (level == current_depth)
  		++current_depth;
  
  	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(dentry_hash) % nbucket));
  
  	for (block = bidx; block <= (bidx + nblock - 1); block++) {
  		dentry_page = f2fs_get_new_data_page(dir, NULL, block, true);
  		if (IS_ERR(dentry_page))
  			return PTR_ERR(dentry_page);
  
  		dentry_blk = page_address(dentry_page);
  		bit_pos = f2fs_room_for_filename(&dentry_blk->dentry_bitmap,
  						slots, NR_DENTRY_IN_BLOCK);
  		if (bit_pos < NR_DENTRY_IN_BLOCK)
  			goto add_dentry;
  
  		f2fs_put_page(dentry_page, 1);
  	}
  
  	/* Move to next level to find the empty slot for new dentry */
  	++level;
  	goto start;
  add_dentry:
  	f2fs_wait_on_page_writeback(dentry_page, DATA, true, true);
  
  	if (inode) {
  		down_write(&F2FS_I(inode)->i_sem);
  		page = f2fs_init_inode_metadata(inode, dir, new_name,
  						orig_name, NULL);
  		if (IS_ERR(page)) {
  			err = PTR_ERR(page);
  			goto fail;
  		}
  	}
  
  	make_dentry_ptr_block(NULL, &d, dentry_blk);
  	f2fs_update_dentry(ino, mode, &d, new_name, dentry_hash, bit_pos);
  
  	set_page_dirty(dentry_page);
  
  	if (inode) {
  		f2fs_i_pino_write(inode, dir->i_ino);
  
  		/* synchronize inode page's data from inode cache */
  		if (is_inode_flag_set(inode, FI_NEW_INODE))
  			f2fs_update_inode(inode, page);
  
  		f2fs_put_page(page, 1);
  	}
  
  	f2fs_update_parent_metadata(dir, inode, current_depth);
  fail:
  	if (inode)
  		up_write(&F2FS_I(inode)->i_sem);
  
  	f2fs_put_page(dentry_page, 1);
  
  	return err;
  }
  
  int f2fs_add_dentry(struct inode *dir, struct fscrypt_name *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);
  	if (err == -EAGAIN)
  		err = f2fs_add_regular_entry(dir, &new_name, fname->usr_fname,
  							inode, ino, mode);
  
  	f2fs_update_time(F2FS_I_SB(dir), REQ_TIME);
  	return err;
  }
  
  /*
   * Caller should grab and release a rwsem by calling f2fs_lock_op() and
   * f2fs_unlock_op().
   */
  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 page *page = NULL;
  	struct f2fs_dir_entry *de = NULL;
  	int err;
  
  	err = fscrypt_setup_filename(dir, name, 0, &fname);
  	if (err)
  		return err;
  
  	/*
  	 * An immature stakable filesystem shows a race condition between lookup
  	 * and create. If we have same task when doing lookup and create, it's
  	 * definitely fine as expected by VFS normally. Otherwise, let's just
  	 * verify on-disk dentry one more time, which guarantees filesystem
  	 * consistency more.
  	 */
  	if (current != F2FS_I(dir)->task) {
  		de = __f2fs_find_entry(dir, &fname, &page);
  		F2FS_I(dir)->task = NULL;
  	}
  	if (de) {
  		f2fs_put_page(page, 0);
  		err = -EEXIST;
  	} else if (IS_ERR(page)) {
  		err = PTR_ERR(page);
  	} else {
  		err = f2fs_add_dentry(dir, &fname, inode, ino, mode);
  	}
  	fscrypt_free_filename(&fname);
  	return err;
  }
  
  int f2fs_do_tmpfile(struct inode *inode, struct inode *dir)
  {
  	struct page *page;
  	int err = 0;
  
  	down_write(&F2FS_I(inode)->i_sem);
  	page = f2fs_init_inode_metadata(inode, dir, NULL, NULL, NULL);
  	if (IS_ERR(page)) {
  		err = PTR_ERR(page);
  		goto fail;
  	}
  	f2fs_put_page(page, 1);
  
  	clear_inode_flag(inode, FI_NEW_INODE);
  	f2fs_update_time(F2FS_I_SB(inode), REQ_TIME);
  fail:
  	up_write(&F2FS_I(inode)->i_sem);
  	return err;
  }
  
  void f2fs_drop_nlink(struct inode *dir, struct inode *inode)
  {
  	struct f2fs_sb_info *sbi = F2FS_I_SB(dir);
  
  	down_write(&F2FS_I(inode)->i_sem);
  
  	if (S_ISDIR(inode->i_mode))
  		f2fs_i_links_write(dir, false);
  	inode->i_ctime = current_time(inode);
  
  	f2fs_i_links_write(inode, false);
  	if (S_ISDIR(inode->i_mode)) {
  		f2fs_i_links_write(inode, false);
  		f2fs_i_size_write(inode, 0);
  	}
  	up_write(&F2FS_I(inode)->i_sem);
  
  	if (inode->i_nlink == 0)
  		f2fs_add_orphan_inode(inode);
  	else
  		f2fs_release_orphan_inode(sbi);
  }
  
  /*
   * It only removes the dentry from the dentry page, corresponding name
   * entry in name page does not need to be touched during deletion.
   */
  void f2fs_delete_entry(struct f2fs_dir_entry *dentry, struct page *page,
  					struct inode *dir, struct inode *inode)
  {
  	struct	f2fs_dentry_block *dentry_blk;
  	unsigned int bit_pos;
  	int slots = GET_DENTRY_SLOTS(le16_to_cpu(dentry->name_len));
  	int i;
  
  	f2fs_update_time(F2FS_I_SB(dir), REQ_TIME);
  
  	if (F2FS_OPTION(F2FS_I_SB(dir)).fsync_mode == FSYNC_MODE_STRICT)
  		f2fs_add_ino_entry(F2FS_I_SB(dir), dir->i_ino, TRANS_DIR_INO);
  
  	if (f2fs_has_inline_dentry(dir))
  		return f2fs_delete_inline_entry(dentry, page, dir, inode);
  
  	lock_page(page);
  	f2fs_wait_on_page_writeback(page, DATA, true, true);
  
  	dentry_blk = page_address(page);
  	bit_pos = dentry - dentry_blk->dentry;
  	for (i = 0; i < slots; i++)
  		__clear_bit_le(bit_pos + i, &dentry_blk->dentry_bitmap);
  
  	/* Let's check and deallocate this dentry page */
  	bit_pos = find_next_bit_le(&dentry_blk->dentry_bitmap,
  			NR_DENTRY_IN_BLOCK,
  			0);
  	set_page_dirty(page);
  
  	if (bit_pos == NR_DENTRY_IN_BLOCK &&
  		!f2fs_truncate_hole(dir, page->index, page->index + 1)) {
  		f2fs_clear_page_cache_dirty_tag(page);
  		clear_page_dirty_for_io(page);
  		f2fs_clear_page_private(page);
  		ClearPageUptodate(page);
  		clear_cold_data(page);
  		inode_dec_dirty_pages(dir);
  		f2fs_remove_dirty_inode(dir);
  	}
  	f2fs_put_page(page, 1);
  
  	dir->i_ctime = dir->i_mtime = current_time(dir);
  	f2fs_mark_inode_dirty_sync(dir, false);
  
  	if (inode)
  		f2fs_drop_nlink(dir, inode);
  }
  
  bool f2fs_empty_dir(struct inode *dir)
  {
  	unsigned long bidx;
  	struct page *dentry_page;
  	unsigned int bit_pos;
  	struct f2fs_dentry_block *dentry_blk;
  	unsigned long nblock = dir_blocks(dir);
  
  	if (f2fs_has_inline_dentry(dir))
  		return f2fs_empty_inline_dir(dir);
  
  	for (bidx = 0; bidx < nblock; bidx++) {
  		dentry_page = f2fs_get_lock_data_page(dir, bidx, false);
  		if (IS_ERR(dentry_page)) {
  			if (PTR_ERR(dentry_page) == -ENOENT)
  				continue;
  			else
  				return false;
  		}
  
  		dentry_blk = page_address(dentry_page);
  		if (bidx == 0)
  			bit_pos = 2;
  		else
  			bit_pos = 0;
  		bit_pos = find_next_bit_le(&dentry_blk->dentry_bitmap,
  						NR_DENTRY_IN_BLOCK,
  						bit_pos);
  
  		f2fs_put_page(dentry_page, 1);
  
  		if (bit_pos < NR_DENTRY_IN_BLOCK)
  			return false;
  	}
  	return true;
  }
  
  int f2fs_fill_dentries(struct dir_context *ctx, struct f2fs_dentry_ptr *d,
  			unsigned int start_pos, struct fscrypt_str *fstr)
  {
  	unsigned char d_type = DT_UNKNOWN;
  	unsigned int bit_pos;
  	struct f2fs_dir_entry *de = NULL;
  	struct fscrypt_str de_name = FSTR_INIT(NULL, 0);
  	struct f2fs_sb_info *sbi = F2FS_I_SB(d->inode);
  	struct blk_plug plug;
  	bool readdir_ra = sbi->readdir_ra == 1;
  	int err = 0;
  
  	bit_pos = ((unsigned long)ctx->pos % d->max);
  
  	if (readdir_ra)
  		blk_start_plug(&plug);
  
  	while (bit_pos < d->max) {
  		bit_pos = find_next_bit_le(d->bitmap, d->max, bit_pos);
  		if (bit_pos >= d->max)
  			break;
  
  		de = &d->dentry[bit_pos];
  		if (de->name_len == 0) {
  			bit_pos++;
  			ctx->pos = start_pos + bit_pos;
  			printk_ratelimited(
  				"%sF2FS-fs (%s): invalid namelen(0), ino:%u, run fsck to fix.",
  				KERN_WARNING, sbi->sb->s_id,
  				le32_to_cpu(de->ino));
  			set_sbi_flag(sbi, SBI_NEED_FSCK);
  			continue;
  		}
  
  		d_type = f2fs_get_de_type(de);
  
  		de_name.name = d->filename[bit_pos];
  		de_name.len = le16_to_cpu(de->name_len);
  
  		/* check memory boundary before moving forward */
  		bit_pos += GET_DENTRY_SLOTS(le16_to_cpu(de->name_len));
  		if (unlikely(bit_pos > d->max ||
  				le16_to_cpu(de->name_len) > F2FS_NAME_LEN)) {
  			f2fs_warn(sbi, "%s: corrupted namelen=%d, run fsck to fix.",
  				  __func__, le16_to_cpu(de->name_len));
  			set_sbi_flag(sbi, SBI_NEED_FSCK);
  			err = -EFSCORRUPTED;
  			goto out;
  		}
  
  		if (IS_ENCRYPTED(d->inode)) {
  			int save_len = fstr->len;
  
  			err = fscrypt_fname_disk_to_usr(d->inode,
  						(u32)le32_to_cpu(de->hash_code),
  						0, &de_name, fstr);
  			if (err)
  				goto out;
  
  			de_name = *fstr;
  			fstr->len = save_len;
  		}
  
  		if (!dir_emit(ctx, de_name.name, de_name.len,
  					le32_to_cpu(de->ino), d_type)) {
  			err = 1;
  			goto out;
  		}
  
  		if (readdir_ra)
  			f2fs_ra_node_page(sbi, le32_to_cpu(de->ino));
  
  		ctx->pos = start_pos + bit_pos;
  	}
  out:
  	if (readdir_ra)
  		blk_finish_plug(&plug);
  	return err;
  }
  
  static int f2fs_readdir(struct file *file, struct dir_context *ctx)
  {
  	struct inode *inode = file_inode(file);
  	unsigned long npages = dir_blocks(inode);
  	struct f2fs_dentry_block *dentry_blk = NULL;
  	struct page *dentry_page = NULL;
  	struct file_ra_state *ra = &file->f_ra;
  	loff_t start_pos = ctx->pos;
  	unsigned int n = ((unsigned long)ctx->pos / NR_DENTRY_IN_BLOCK);
  	struct f2fs_dentry_ptr d;
  	struct fscrypt_str fstr = FSTR_INIT(NULL, 0);
  	int err = 0;
  
  	if (IS_ENCRYPTED(inode)) {
  		err = fscrypt_get_encryption_info(inode);
  		if (err)
  			goto out;
  
  		err = fscrypt_fname_alloc_buffer(inode, F2FS_NAME_LEN, &fstr);
  		if (err < 0)
  			goto out;
  	}
  
  	if (f2fs_has_inline_dentry(inode)) {
  		err = f2fs_read_inline_dir(file, ctx, &fstr);
  		goto out_free;
  	}
  
  	for (; n < npages; n++, ctx->pos = n * NR_DENTRY_IN_BLOCK) {
  
  		/* allow readdir() to be interrupted */
  		if (fatal_signal_pending(current)) {
  			err = -ERESTARTSYS;
  			goto out_free;
  		}
  		cond_resched();
  
  		/* readahead for multi pages of dir */
  		if (npages - n > 1 && !ra_has_index(ra, n))
  			page_cache_sync_readahead(inode->i_mapping, ra, file, n,
  				min(npages - n, (pgoff_t)MAX_DIR_RA_PAGES));
  
  		dentry_page = f2fs_find_data_page(inode, n);
  		if (IS_ERR(dentry_page)) {
  			err = PTR_ERR(dentry_page);
  			if (err == -ENOENT) {
  				err = 0;
  				continue;
  			} else {
  				goto out_free;
  			}
  		}
  
  		dentry_blk = page_address(dentry_page);
  
  		make_dentry_ptr_block(inode, &d, dentry_blk);
  
  		err = f2fs_fill_dentries(ctx, &d,
  				n * NR_DENTRY_IN_BLOCK, &fstr);
  		if (err) {
  			f2fs_put_page(dentry_page, 0);
  			break;
  		}
  
  		f2fs_put_page(dentry_page, 0);
  	}
  out_free:
  	fscrypt_fname_free_buffer(&fstr);
  out:
  	trace_f2fs_readdir(inode, start_pos, ctx->pos, err);
  	return err < 0 ? err : 0;
  }
  
  static int f2fs_dir_open(struct inode *inode, struct file *filp)
  {
  	if (IS_ENCRYPTED(inode))
  		return fscrypt_get_encryption_info(inode) ? -EACCES : 0;
  	return 0;
  }
  
  const struct file_operations f2fs_dir_operations = {
  	.llseek		= generic_file_llseek,
  	.read		= generic_read_dir,
  	.iterate_shared	= f2fs_readdir,
  	.fsync		= f2fs_sync_file,
  	.open		= f2fs_dir_open,
  	.unlocked_ioctl	= f2fs_ioctl,
  #ifdef CONFIG_COMPAT
  	.compat_ioctl   = f2fs_compat_ioctl,
  #endif
  };
  
  #ifdef CONFIG_UNICODE
  static int f2fs_d_compare(const struct dentry *dentry, unsigned int len,
  			  const char *str, const struct qstr *name)
  {
  	struct qstr qstr = {.name = str, .len = len };
  	const struct dentry *parent = READ_ONCE(dentry->d_parent);
  	const struct inode *inode = READ_ONCE(parent->d_inode);
  
  	if (!inode || !IS_CASEFOLDED(inode)) {
  		if (len != name->len)
  			return -1;
  		return memcmp(str, name->name, len);
  	}
  
  	return f2fs_ci_compare(inode, name, &qstr, false);
  }
  
  static int f2fs_d_hash(const struct dentry *dentry, struct qstr *str)
  {
  	struct f2fs_sb_info *sbi = F2FS_SB(dentry->d_sb);
  	const struct unicode_map *um = sbi->s_encoding;
  	const struct inode *inode = READ_ONCE(dentry->d_inode);
  	unsigned char *norm;
  	int len, ret = 0;
  
  	if (!inode || !IS_CASEFOLDED(inode))
  		return 0;
  
  	norm = f2fs_kmalloc(sbi, PATH_MAX, GFP_ATOMIC);
  	if (!norm)
  		return -ENOMEM;
  
  	len = utf8_casefold(um, str, norm, PATH_MAX);
  	if (len < 0) {
  		if (f2fs_has_strict_mode(sbi))
  			ret = -EINVAL;
  		goto out;
  	}
  	str->hash = full_name_hash(dentry, norm, len);
  out:
  	kvfree(norm);
  	return ret;
  }
  
  const struct dentry_operations f2fs_dentry_ops = {
  	.d_hash = f2fs_d_hash,
  	.d_compare = f2fs_d_compare,
  };
  #endif
  