static int ext4_htree_next_block(struct inode *dir, __u32 hash,
				 struct dx_frame *frame,
				 struct dx_frame *frames,
				 __u32 *start_hash)
{
	struct dx_frame *p;
	struct buffer_head *bh;
	int num_frames = 0;
	__u32 bhash;

	p = frame;
	/*
	 * Find the next leaf page by incrementing the frame pointer.
	 * If we run out of entries in the interior node, loop around and
	 * increment pointer in the parent node.  When we break out of
	 * this loop, num_frames indicates the number of interior
	 * nodes need to be read.
	 */
	while (1) {
		if (++(p->at) < p->entries + dx_get_count(p->entries))
			break;
		if (p == frames)
			return 0;
		num_frames++;
		p--;
	}

	/*
	 * If the hash is 1, then continue only if the next page has a
	 * continuation hash of any value.  This is used for readdir
	 * handling.  Otherwise, check to see if the hash matches the
	 * desired contiuation hash.  If it doesn't, return since
	 * there's no point to read in the successive index pages.
	 */
	bhash = dx_get_hash(p->at);
	if (start_hash)
		*start_hash = bhash;
	if ((hash & 1) == 0) {
		if ((bhash & ~1) != hash)
			return 0;
	}
	/*
	 * If the hash is HASH_NB_ALWAYS, we always go to the next
	 * block so no check is necessary
	 */
	while (num_frames--) {
		bh = ext4_read_dirblock(dir, dx_get_block(p->at), INDEX);
		if (IS_ERR(bh))
			return PTR_ERR(bh);
		p++;
		brelse(p->bh);
		p->bh = bh;
		p->at = p->entries = ((struct dx_node *) bh->b_data)->entries;
	}
	return 1;
}


static int ext4_find_delete_entry(handle_t *handle, struct inode *dir,
				  const struct qstr *d_name)
{
	int retval = -ENOENT;
	struct buffer_head *bh;
	struct ext4_dir_entry_2 *de;

	bh = ext4_find_entry(dir, d_name, &de, NULL);
	if (IS_ERR(bh))
		return PTR_ERR(bh);
	if (bh) {
		retval = ext4_delete_entry(handle, dir, de, bh);
		brelse(bh);
	}
	return retval;
}

ext4: fix potential negative array index in do_split()

If for any reason a directory passed to do_split() does not have enough
active entries to exceed half the size of the block, we can end up
iterating over all "count" entries without finding a split point.

In this case, count == move, and split will be zero, and we will
attempt a negative index into map[].

Guard against this by detecting this case, and falling back to
split-to-half-of-count instead; in this case we will still have
plenty of space (> half blocksize) in each split block.

Fixes: ef2b02d3e617 ("ext34: ensure do_split leaves enough free space in both blocks")
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/f53e246b-647c-64bb-16ec-135383c70ad7@redhat.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

static int ext4_dx_csum_verify(struct inode *inode,
			       struct ext4_dir_entry *dirent);

#define ext4_read_dirblock(inode, block, type) \
	__ext4_read_dirblock((inode), (block), (type), __func__, __LINE__)

struct fake_dirent
{
	__le32 inode;
	__le16 rec_len;
	u8 name_len;
	u8 file_type;
}

struct dx_countlimit
{
	__le16 limit;
	__le16 count;
}

struct dx_entry
{
	__le32 hash;
	__le32 block;
}

struct dx_root
{
	struct fake_dirent dot;
	char dot_name[4];
	struct fake_dirent dotdot;
	char dotdot_name[4];
	struct dx_root_info
	{
		__le32 reserved_zero;
		u8 hash_version;
		u8 info_length; /* 8 */
		u8 indirect_levels;
		u8 unused_flags;
	}
	info;
	struct dx_entry	entries[];
}

struct dx_node
{
	struct fake_dirent fake;
	struct dx_entry	entries[];
}

struct dx_frame
{
	struct buffer_head *bh;
	struct dx_entry *entries;
	struct dx_entry *at;
}

struct dx_map_entry
{
	u32 hash;
	u16 offs;
	u16 size;
}

struct dx_tail {
	u32 dt_reserved;
	__le32 dt_checksum;	/* crc32c(uuid+inum+dirblock) */
}

static inline ext4_lblk_t dx_get_block(struct dx_entry *entry);

static void dx_set_block(struct dx_entry *entry, ext4_lblk_t value);

static inline unsigned dx_get_hash(struct dx_entry *entry);

static void dx_set_hash(struct dx_entry *entry, unsigned value);

static unsigned dx_get_count(struct dx_entry *entries);

static unsigned dx_get_limit(struct dx_entry *entries);

static void dx_set_count(struct dx_entry *entries, unsigned value);

static void dx_set_limit(struct dx_entry *entries, unsigned value);

static unsigned dx_root_limit(struct inode *dir, unsigned infosize);

static unsigned dx_node_limit(struct inode *dir);

static struct dx_frame *dx_probe(struct ext4_filename *fname,
				 struct inode *dir,
				 struct dx_hash_info *hinfo,
				 struct dx_frame *frame);

static void dx_release(struct dx_frame *frames);

static int dx_make_map(struct inode *dir, struct ext4_dir_entry_2 *de,
		       unsigned blocksize, struct dx_hash_info *hinfo,
		       struct dx_map_entry map[]);

static void dx_sort_map(struct dx_map_entry *map, unsigned count);

static struct ext4_dir_entry_2 *dx_move_dirents(char *from, char *to,
		struct dx_map_entry *offsets, int count, unsigned blocksize);

static struct ext4_dir_entry_2* dx_pack_dirents(char *base, unsigned blocksize);

static void dx_insert_block(struct dx_frame *frame,
					u32 hash, ext4_lblk_t block);

static int ext4_htree_next_block(struct inode *dir, __u32 hash,
				 struct dx_frame *frame,
				 struct dx_frame *frames,
				 __u32 *start_hash);

static struct buffer_head * ext4_dx_find_entry(struct inode *dir,
		struct ext4_filename *fname,
		struct ext4_dir_entry_2 **res_dir);

static int ext4_dx_add_entry(handle_t *handle, struct ext4_filename *fname,
			     struct inode *dir, struct inode *inode);

#define warn_no_space_for_csum(inode)					\
	__warn_no_space_for_csum((inode), __func__, __LINE__)

struct stats
{
	unsigned names;
	unsigned space;
	unsigned bcount;
}


static inline void dx_set_block(struct dx_entry *entry, ext4_lblk_t value)
{
	entry->block = cpu_to_le32(value);
}


static struct ext4_dir_entry_2 *do_split(handle_t *handle, struct inode *dir,
			struct buffer_head **bh,struct dx_frame *frame,
			struct dx_hash_info *hinfo)
{
	unsigned blocksize = dir->i_sb->s_blocksize;
	unsigned count, continued;
	struct buffer_head *bh2;
	ext4_lblk_t newblock;
	u32 hash2;
	struct dx_map_entry *map;
	char *data1 = (*bh)->b_data, *data2;
	unsigned split, move, size;
	struct ext4_dir_entry_2 *de = NULL, *de2;
	int	csum_size = 0;
	int	err = 0, i;

	if (ext4_has_metadata_csum(dir->i_sb))
		csum_size = sizeof(struct ext4_dir_entry_tail);

	bh2 = ext4_append(handle, dir, &newblock);
	if (IS_ERR(bh2)) {
		brelse(*bh);
		*bh = NULL;
		return (struct ext4_dir_entry_2 *) bh2;
	}

	BUFFER_TRACE(*bh, "get_write_access");
	err = ext4_journal_get_write_access(handle, *bh);
	if (err)
		goto journal_error;

	BUFFER_TRACE(frame->bh, "get_write_access");
	err = ext4_journal_get_write_access(handle, frame->bh);
	if (err)
		goto journal_error;

	data2 = bh2->b_data;

	/* create map in the end of data2 block */
	map = (struct dx_map_entry *) (data2 + blocksize);
	count = dx_make_map(dir, (struct ext4_dir_entry_2 *) data1,
			     blocksize, hinfo, map);
	map -= count;
	dx_sort_map(map, count);
	/* Ensure that neither split block is over half full */
	size = 0;
	move = 0;
	for (i = count-1; i >= 0; i--) {
		/* is more than half of this entry in 2nd half of the block? */
		if (size + map[i].size/2 > blocksize/2)
			break;
		size += map[i].size;
		move++;
	}
	/*
	 * map index at which we will split
	 *
	 * If the sum of active entries didn't exceed half the block size, just
	 * split it in half by count; each resulting block will have at least
	 * half the space free.
	 */
	if (i > 0)
		split = count - move;
	else
		split = count/2;

	hash2 = map[split].hash;
	continued = hash2 == map[split - 1].hash;
	dxtrace(printk(KERN_INFO "Split block %lu at %x, %i/%i\n",
			(unsigned long)dx_get_block(frame->at),
					hash2, split, count-split));

	/* Fancy dance to stay within two buffers */
	de2 = dx_move_dirents(data1, data2, map + split, count - split,
			      blocksize);
	de = dx_pack_dirents(data1, blocksize);
	de->rec_len = ext4_rec_len_to_disk(data1 + (blocksize - csum_size) -
					   (char *) de,
					   blocksize);
	de2->rec_len = ext4_rec_len_to_disk(data2 + (blocksize - csum_size) -
					    (char *) de2,
					    blocksize);
	if (csum_size) {
		ext4_initialize_dirent_tail(*bh, blocksize);
		ext4_initialize_dirent_tail(bh2, blocksize);
	}

	dxtrace(dx_show_leaf(dir, hinfo, (struct ext4_dir_entry_2 *) data1,
			blocksize, 1));
	dxtrace(dx_show_leaf(dir, hinfo, (struct ext4_dir_entry_2 *) data2,
			blocksize, 1));

	/* Which block gets the new entry? */
	if (hinfo->hash >= hash2) {
		swap(*bh, bh2);
		de = de2;
	}
	dx_insert_block(frame, hash2 + continued, newblock);
	err = ext4_handle_dirty_dirblock(handle, dir, bh2);
	if (err)
		goto journal_error;
	err = ext4_handle_dirty_dx_node(handle, dir, frame->bh);
	if (err)
		goto journal_error;
	brelse(bh2);
	dxtrace(dx_show_index("frame", frame->entries));
	return de;

journal_error:
	brelse(*bh);
	brelse(bh2);
	*bh = NULL;
	ext4_std_error(dir->i_sb, err);
	return ERR_PTR(err);
}

static int ext4_dx_csum_verify(struct inode *inode,
			       struct ext4_dir_entry *dirent);

#define ext4_read_dirblock(inode, block, type) \
	__ext4_read_dirblock((inode), (block), (type), __func__, __LINE__)

#define dxtrace(command) command

#define dxtrace(command)

struct fake_dirent
{
	__le32 inode;
	__le16 rec_len;
	u8 name_len;
	u8 file_type;
}

struct dx_countlimit
{
	__le16 limit;
	__le16 count;
}

struct dx_entry
{
	__le32 hash;
	__le32 block;
}

struct dx_root
{
	struct fake_dirent dot;
	char dot_name[4];
	struct fake_dirent dotdot;
	char dotdot_name[4];
	struct dx_root_info
	{
		__le32 reserved_zero;
		u8 hash_version;
		u8 info_length; /* 8 */
		u8 indirect_levels;
		u8 unused_flags;
	}
	info;
	struct dx_entry	entries[];
}

struct dx_node
{
	struct fake_dirent fake;
	struct dx_entry	entries[];
}

struct dx_frame
{
	struct buffer_head *bh;
	struct dx_entry *entries;
	struct dx_entry *at;
}

struct dx_map_entry
{
	u32 hash;
	u16 offs;
	u16 size;
}

struct dx_tail {
	u32 dt_reserved;
	__le32 dt_checksum;	/* crc32c(uuid+inum+dirblock) */
}

static inline ext4_lblk_t dx_get_block(struct dx_entry *entry);

static void dx_set_block(struct dx_entry *entry, ext4_lblk_t value);

static inline unsigned dx_get_hash(struct dx_entry *entry);

static void dx_set_hash(struct dx_entry *entry, unsigned value);

static unsigned dx_get_count(struct dx_entry *entries);

static unsigned dx_get_limit(struct dx_entry *entries);

static void dx_set_count(struct dx_entry *entries, unsigned value);

static void dx_set_limit(struct dx_entry *entries, unsigned value);

static unsigned dx_root_limit(struct inode *dir, unsigned infosize);

static unsigned dx_node_limit(struct inode *dir);

static struct dx_frame *dx_probe(struct ext4_filename *fname,
				 struct inode *dir,
				 struct dx_hash_info *hinfo,
				 struct dx_frame *frame);

static void dx_release(struct dx_frame *frames);

static int dx_make_map(struct inode *dir, struct ext4_dir_entry_2 *de,
		       unsigned blocksize, struct dx_hash_info *hinfo,
		       struct dx_map_entry map[]);

static void dx_sort_map(struct dx_map_entry *map, unsigned count);

static struct ext4_dir_entry_2 *dx_move_dirents(char *from, char *to,
		struct dx_map_entry *offsets, int count, unsigned blocksize);

static struct ext4_dir_entry_2* dx_pack_dirents(char *base, unsigned blocksize);

static void dx_insert_block(struct dx_frame *frame,
					u32 hash, ext4_lblk_t block);

static int ext4_htree_next_block(struct inode *dir, __u32 hash,
				 struct dx_frame *frame,
				 struct dx_frame *frames,
				 __u32 *start_hash);

static struct buffer_head * ext4_dx_find_entry(struct inode *dir,
		struct ext4_filename *fname,
		struct ext4_dir_entry_2 **res_dir);

static int ext4_dx_add_entry(handle_t *handle, struct ext4_filename *fname,
			     struct inode *dir, struct inode *inode);

#define warn_no_space_for_csum(inode)					\
	__warn_no_space_for_csum((inode), __func__, __LINE__)


static void ext4_update_dir_count(handle_t *handle, struct ext4_renament *ent)
{
	if (ent->dir_nlink_delta) {
		if (ent->dir_nlink_delta == -1)
			ext4_dec_count(handle, ent->dir);
		else
			ext4_inc_count(handle, ent->dir);
		ext4_mark_inode_dirty(handle, ent->dir);
	}
}

static int ext4_dx_csum_verify(struct inode *inode,
			       struct ext4_dir_entry *dirent);

struct fake_dirent
{
	__le32 inode;
	__le16 rec_len;
	u8 name_len;
	u8 file_type;
}

struct dx_countlimit
{
	__le16 limit;
	__le16 count;
}

struct dx_entry
{
	__le32 hash;
	__le32 block;
}

struct dx_root
{
	struct fake_dirent dot;
	char dot_name[4];
	struct fake_dirent dotdot;
	char dotdot_name[4];
	struct dx_root_info
	{
		__le32 reserved_zero;
		u8 hash_version;
		u8 info_length; /* 8 */
		u8 indirect_levels;
		u8 unused_flags;
	}
	info;
	struct dx_entry	entries[];
}

struct dx_node
{
	struct fake_dirent fake;
	struct dx_entry	entries[];
}

struct dx_frame
{
	struct buffer_head *bh;
	struct dx_entry *entries;
	struct dx_entry *at;
}

struct dx_map_entry
{
	u32 hash;
	u16 offs;
	u16 size;
}

struct dx_tail {
	u32 dt_reserved;
	__le32 dt_checksum;	/* crc32c(uuid+inum+dirblock) */
}

static inline ext4_lblk_t dx_get_block(struct dx_entry *entry);

static void dx_set_block(struct dx_entry *entry, ext4_lblk_t value);

static inline unsigned dx_get_hash(struct dx_entry *entry);

static void dx_set_hash(struct dx_entry *entry, unsigned value);

static unsigned dx_get_count(struct dx_entry *entries);

static unsigned dx_get_limit(struct dx_entry *entries);

static void dx_set_count(struct dx_entry *entries, unsigned value);

static void dx_set_limit(struct dx_entry *entries, unsigned value);

static unsigned dx_root_limit(struct inode *dir, unsigned infosize);

static unsigned dx_node_limit(struct inode *dir);

static struct dx_frame *dx_probe(struct ext4_filename *fname,
				 struct inode *dir,
				 struct dx_hash_info *hinfo,
				 struct dx_frame *frame);

static void dx_release(struct dx_frame *frames);

static int dx_make_map(struct inode *dir, struct ext4_dir_entry_2 *de,
		       unsigned blocksize, struct dx_hash_info *hinfo,
		       struct dx_map_entry map[]);

static void dx_sort_map(struct dx_map_entry *map, unsigned count);

static struct ext4_dir_entry_2 *dx_move_dirents(char *from, char *to,
		struct dx_map_entry *offsets, int count, unsigned blocksize);

static struct ext4_dir_entry_2* dx_pack_dirents(char *base, unsigned blocksize);

static void dx_insert_block(struct dx_frame *frame,
					u32 hash, ext4_lblk_t block);

static int ext4_htree_next_block(struct inode *dir, __u32 hash,
				 struct dx_frame *frame,
				 struct dx_frame *frames,
				 __u32 *start_hash);

static struct buffer_head * ext4_dx_find_entry(struct inode *dir,
		struct ext4_filename *fname,
		struct ext4_dir_entry_2 **res_dir);

static int ext4_dx_add_entry(handle_t *handle, struct ext4_filename *fname,
			     struct inode *dir, struct inode *inode);

struct stats
{
	unsigned names;
	unsigned space;
	unsigned bcount;
}


int ext4_dirblock_csum_verify(struct inode *inode, struct buffer_head *bh)
{
	struct ext4_dir_entry_tail *t;

	if (!ext4_has_metadata_csum(inode->i_sb))
		return 1;

	t = get_dirent_tail(inode, bh);
	if (!t) {
		warn_no_space_for_csum(inode);
		return 0;
	}

	if (t->det_checksum != ext4_dirblock_csum(inode, bh->b_data,
						  (char *)t - bh->b_data))
		return 0;

	return 1;
}


static int ext4_unlink(struct inode *dir, struct dentry *dentry)
{
	int retval;
	struct inode *inode;
	struct buffer_head *bh;
	struct ext4_dir_entry_2 *de;
	handle_t *handle = NULL;

	if (unlikely(ext4_forced_shutdown(EXT4_SB(dir->i_sb))))
		return -EIO;

	trace_ext4_unlink_enter(dir, dentry);
	/* Initialize quotas before so that eventual writes go
	 * in separate transaction */
	retval = dquot_initialize(dir);
	if (retval)
		return retval;
	retval = dquot_initialize(d_inode(dentry));
	if (retval)
		return retval;

	retval = -ENOENT;
	bh = ext4_find_entry(dir, &dentry->d_name, &de, NULL);
	if (IS_ERR(bh))
		return PTR_ERR(bh);
	if (!bh)
		goto end_unlink;

	inode = d_inode(dentry);

	retval = -EFSCORRUPTED;
	if (le32_to_cpu(de->inode) != inode->i_ino)
		goto end_unlink;

	handle = ext4_journal_start(dir, EXT4_HT_DIR,
				    EXT4_DATA_TRANS_BLOCKS(dir->i_sb));
	if (IS_ERR(handle)) {
		retval = PTR_ERR(handle);
		handle = NULL;
		goto end_unlink;
	}

	if (IS_DIRSYNC(dir))
		ext4_handle_sync(handle);

	retval = ext4_delete_entry(handle, dir, de, bh);
	if (retval)
		goto end_unlink;
	dir->i_ctime = dir->i_mtime = current_time(dir);
	ext4_update_dx_flag(dir);
	retval = ext4_mark_inode_dirty(handle, dir);
	if (retval)
		goto end_unlink;
	if (inode->i_nlink == 0)
		ext4_warning_inode(inode, "Deleting file '%.*s' with no links",
				   dentry->d_name.len, dentry->d_name.name);
	else
		drop_nlink(inode);
	if (!inode->i_nlink)
		ext4_orphan_add(handle, inode);
	inode->i_ctime = current_time(inode);
	retval = ext4_mark_inode_dirty(handle, inode);

#ifdef 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))
		d_invalidate(dentry);
#endif

end_unlink:
	brelse(bh);
	if (handle)
		ext4_journal_stop(handle);
	trace_ext4_unlink_exit(dentry, retval);
	return retval;
}


bool ext4_empty_dir(struct inode *inode)
{
	unsigned int offset;
	struct buffer_head *bh;
	struct ext4_dir_entry_2 *de;
	struct super_block *sb;

	if (ext4_has_inline_data(inode)) {
		int has_inline_data = 1;
		int ret;

		ret = empty_inline_dir(inode, &has_inline_data);
		if (has_inline_data)
			return ret;
	}

	sb = inode->i_sb;
	if (inode->i_size < EXT4_DIR_REC_LEN(1) + EXT4_DIR_REC_LEN(2)) {
		EXT4_ERROR_INODE(inode, "invalid size");
		return true;
	}
	/* The first directory block must not be a hole,
	 * so treat it as DIRENT_HTREE
	 */
	bh = ext4_read_dirblock(inode, 0, DIRENT_HTREE);
	if (IS_ERR(bh))
		return true;

	de = (struct ext4_dir_entry_2 *) bh->b_data;
	if (ext4_check_dir_entry(inode, NULL, de, bh, bh->b_data, bh->b_size,
				 0) ||
	    le32_to_cpu(de->inode) != inode->i_ino || strcmp(".", de->name)) {
		ext4_warning_inode(inode, "directory missing '.'");
		brelse(bh);
		return true;
	}
	offset = ext4_rec_len_from_disk(de->rec_len, sb->s_blocksize);
	de = ext4_next_entry(de, sb->s_blocksize);
	if (ext4_check_dir_entry(inode, NULL, de, bh, bh->b_data, bh->b_size,
				 offset) ||
	    le32_to_cpu(de->inode) == 0 || strcmp("..", de->name)) {
		ext4_warning_inode(inode, "directory missing '..'");
		brelse(bh);
		return true;
	}
	offset += ext4_rec_len_from_disk(de->rec_len, sb->s_blocksize);
	while (offset < inode->i_size) {
		if (!(offset & (sb->s_blocksize - 1))) {
			unsigned int lblock;
			brelse(bh);
			lblock = offset >> EXT4_BLOCK_SIZE_BITS(sb);
			bh = ext4_read_dirblock(inode, lblock, EITHER);
			if (bh == NULL) {
				offset += sb->s_blocksize;
				continue;
			}
			if (IS_ERR(bh))
				return true;
		}
		de = (struct ext4_dir_entry_2 *) (bh->b_data +
					(offset & (sb->s_blocksize - 1)));
		if (ext4_check_dir_entry(inode, NULL, de, bh,
					 bh->b_data, bh->b_size, offset)) {
			offset = (offset | (sb->s_blocksize - 1)) + 1;
			continue;
		}
		if (le32_to_cpu(de->inode)) {
			brelse(bh);
			return false;
		}
		offset += ext4_rec_len_from_disk(de->rec_len, sb->s_blocksize);
	}
	brelse(bh);
	return true;
}

static int ext4_dx_csum_verify(struct inode *inode,
			       struct ext4_dir_entry *dirent);

typedef enum {
	EITHER, INDEX, DIRENT, DIRENT_HTREE
} dirblock_type_t;

#define ext4_read_dirblock(inode, block, type) \
	__ext4_read_dirblock((inode), (block), (type), __func__, __LINE__)

struct fake_dirent
{
	__le32 inode;
	__le16 rec_len;
	u8 name_len;
	u8 file_type;
}

struct dx_countlimit
{
	__le16 limit;
	__le16 count;
}

struct dx_entry
{
	__le32 hash;
	__le32 block;
}

struct dx_root
{
	struct fake_dirent dot;
	char dot_name[4];
	struct fake_dirent dotdot;
	char dotdot_name[4];
	struct dx_root_info
	{
		__le32 reserved_zero;
		u8 hash_version;
		u8 info_length; /* 8 */
		u8 indirect_levels;
		u8 unused_flags;
	}
	info;
	struct dx_entry	entries[];
}

struct dx_node
{
	struct fake_dirent fake;
	struct dx_entry	entries[];
}

struct dx_frame
{
	struct buffer_head *bh;
	struct dx_entry *entries;
	struct dx_entry *at;
}

struct dx_map_entry
{
	u32 hash;
	u16 offs;
	u16 size;
}

struct dx_tail {
	u32 dt_reserved;
	__le32 dt_checksum;	/* crc32c(uuid+inum+dirblock) */
}

static inline ext4_lblk_t dx_get_block(struct dx_entry *entry);

static void dx_set_block(struct dx_entry *entry, ext4_lblk_t value);

static inline unsigned dx_get_hash(struct dx_entry *entry);

static void dx_set_hash(struct dx_entry *entry, unsigned value);

static unsigned dx_get_count(struct dx_entry *entries);

static unsigned dx_get_limit(struct dx_entry *entries);

static void dx_set_count(struct dx_entry *entries, unsigned value);

static void dx_set_limit(struct dx_entry *entries, unsigned value);

static unsigned dx_root_limit(struct inode *dir, unsigned infosize);

static unsigned dx_node_limit(struct inode *dir);

static struct dx_frame *dx_probe(struct ext4_filename *fname,
				 struct inode *dir,
				 struct dx_hash_info *hinfo,
				 struct dx_frame *frame);

static void dx_release(struct dx_frame *frames);

static int dx_make_map(struct inode *dir, struct ext4_dir_entry_2 *de,
		       unsigned blocksize, struct dx_hash_info *hinfo,
		       struct dx_map_entry map[]);

static void dx_sort_map(struct dx_map_entry *map, unsigned count);

static struct ext4_dir_entry_2 *dx_move_dirents(char *from, char *to,
		struct dx_map_entry *offsets, int count, unsigned blocksize);

static struct ext4_dir_entry_2* dx_pack_dirents(char *base, unsigned blocksize);

static void dx_insert_block(struct dx_frame *frame,
					u32 hash, ext4_lblk_t block);

static int ext4_htree_next_block(struct inode *dir, __u32 hash,
				 struct dx_frame *frame,
				 struct dx_frame *frames,
				 __u32 *start_hash);

static struct buffer_head * ext4_dx_find_entry(struct inode *dir,
		struct ext4_filename *fname,
		struct ext4_dir_entry_2 **res_dir);

static int ext4_dx_add_entry(handle_t *handle, struct ext4_filename *fname,
			     struct inode *dir, struct inode *inode);

#define warn_no_space_for_csum(inode)					\
	__warn_no_space_for_csum((inode), __func__, __LINE__)


static __le32 ext4_dirblock_csum(struct inode *inode, void *dirent, int size)
{
	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
	struct ext4_inode_info *ei = EXT4_I(inode);
	__u32 csum;

	csum = ext4_chksum(sbi, ei->i_csum_seed, (__u8 *)dirent, size);
	return cpu_to_le32(csum);
}


static void ext4_dx_csum_set(struct inode *inode, struct ext4_dir_entry *dirent)
{
	struct dx_countlimit *c;
	struct dx_tail *t;
	int count_offset, limit, count;

	if (!ext4_has_metadata_csum(inode->i_sb))
		return;

	c = get_dx_countlimit(inode, dirent, &count_offset);
	if (!c) {
		EXT4_ERROR_INODE(inode, "dir seems corrupt?  Run e2fsck -D.");
		return;
	}
	limit = le16_to_cpu(c->limit);
	count = le16_to_cpu(c->count);
	if (count_offset + (limit * sizeof(struct dx_entry)) >
	    EXT4_BLOCK_SIZE(inode->i_sb) - sizeof(struct dx_tail)) {
		warn_no_space_for_csum(inode);
		return;
	}
	t = (struct dx_tail *)(((struct dx_entry *)c) + limit);

	t->dt_checksum = ext4_dx_csum(inode, dirent, count_offset, count, t);
}


static int ext4_mknod(struct inode *dir, struct dentry *dentry,
		      umode_t mode, dev_t rdev)
{
	handle_t *handle;
	struct inode *inode;
	int err, credits, retries = 0;

	err = dquot_initialize(dir);
	if (err)
		return err;

	credits = (EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
		   EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3);
retry:
	inode = ext4_new_inode_start_handle(dir, mode, &dentry->d_name, 0,
					    NULL, EXT4_HT_DIR, credits);
	handle = ext4_journal_current_handle();
	err = PTR_ERR(inode);
	if (!IS_ERR(inode)) {
		init_special_inode(inode, inode->i_mode, rdev);
		inode->i_op = &ext4_special_inode_operations;
		err = ext4_add_nondir(handle, dentry, &inode);
	}
	if (handle)
		ext4_journal_stop(handle);
	if (!IS_ERR_OR_NULL(inode))
		iput(inode);
	if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
		goto retry;
	return err;
}


static int ext4_add_entry(handle_t *handle, struct dentry *dentry,
			  struct inode *inode)
{
	struct inode *dir = d_inode(dentry->d_parent);
	struct buffer_head *bh = NULL;
	struct ext4_dir_entry_2 *de;
	struct super_block *sb;
#ifdef CONFIG_UNICODE
	struct ext4_sb_info *sbi;
#endif
	struct ext4_filename fname;
	int	retval;
	int	dx_fallback=0;
	unsigned blocksize;
	ext4_lblk_t block, blocks;
	int	csum_size = 0;

	if (ext4_has_metadata_csum(inode->i_sb))
		csum_size = sizeof(struct ext4_dir_entry_tail);

	sb = dir->i_sb;
	blocksize = sb->s_blocksize;
	if (!dentry->d_name.len)
		return -EINVAL;

#ifdef CONFIG_UNICODE
	sbi = EXT4_SB(sb);
	if (ext4_has_strict_mode(sbi) && IS_CASEFOLDED(dir) &&
	    sbi->s_encoding && utf8_validate(sbi->s_encoding, &dentry->d_name))
		return -EINVAL;
#endif

	retval = ext4_fname_setup_filename(dir, &dentry->d_name, 0, &fname);
	if (retval)
		return retval;

	if (ext4_has_inline_data(dir)) {
		retval = ext4_try_add_inline_entry(handle, &fname, dir, inode);
		if (retval < 0)
			goto out;
		if (retval == 1) {
			retval = 0;
			goto out;
		}
	}

	if (is_dx(dir)) {
		retval = ext4_dx_add_entry(handle, &fname, dir, inode);
		if (!retval || (retval != ERR_BAD_DX_DIR))
			goto out;
		/* Can we just ignore htree data? */
		if (ext4_has_metadata_csum(sb)) {
			EXT4_ERROR_INODE(dir,
				"Directory has corrupted htree index.");
			retval = -EFSCORRUPTED;
			goto out;
		}
		ext4_clear_inode_flag(dir, EXT4_INODE_INDEX);
		dx_fallback++;
		retval = ext4_mark_inode_dirty(handle, dir);
		if (unlikely(retval))
			goto out;
	}
	blocks = dir->i_size >> sb->s_blocksize_bits;
	for (block = 0; block < blocks; block++) {
		bh = ext4_read_dirblock(dir, block, DIRENT);
		if (bh == NULL) {
			bh = ext4_bread(handle, dir, block,
					EXT4_GET_BLOCKS_CREATE);
			goto add_to_new_block;
		}
		if (IS_ERR(bh)) {
			retval = PTR_ERR(bh);
			bh = NULL;
			goto out;
		}
		retval = add_dirent_to_buf(handle, &fname, dir, inode,
					   NULL, bh);
		if (retval != -ENOSPC)
			goto out;

		if (blocks == 1 && !dx_fallback &&
		    ext4_has_feature_dir_index(sb)) {
			retval = make_indexed_dir(handle, &fname, dir,
						  inode, bh);
			bh = NULL; /* make_indexed_dir releases bh */
			goto out;
		}
		brelse(bh);
	}
	bh = ext4_append(handle, dir, &block);
add_to_new_block:
	if (IS_ERR(bh)) {
		retval = PTR_ERR(bh);
		bh = NULL;
		goto out;
	}
	de = (struct ext4_dir_entry_2 *) bh->b_data;
	de->inode = 0;
	de->rec_len = ext4_rec_len_to_disk(blocksize - csum_size, blocksize);

	if (csum_size)
		ext4_initialize_dirent_tail(bh, blocksize);

	retval = add_dirent_to_buf(handle, &fname, dir, inode, de, bh);
out:
	ext4_fname_free_filename(&fname);
	brelse(bh);
	if (retval == 0)
		ext4_set_inode_state(inode, EXT4_STATE_NEWENTRY);
	return retval;
}


struct dentry *ext4_get_parent(struct dentry *child)
{
	__u32 ino;
	static const struct qstr dotdot = QSTR_INIT("..", 2);
	struct ext4_dir_entry_2 * de;
	struct buffer_head *bh;

	bh = ext4_find_entry(d_inode(child), &dotdot, &de, NULL);
	if (IS_ERR(bh))
		return ERR_CAST(bh);
	if (!bh)
		return ERR_PTR(-ENOENT);
	ino = le32_to_cpu(de->inode);
	brelse(bh);

	if (!ext4_valid_inum(child->d_sb, ino)) {
		EXT4_ERROR_INODE(d_inode(child),
				 "bad parent inode number: %u", ino);
		return ERR_PTR(-EFSCORRUPTED);
	}

	return d_obtain_alias(ext4_iget(child->d_sb, ino, EXT4_IGET_NORMAL));
}


int ext4_htree_fill_tree(struct file *dir_file, __u32 start_hash,
			 __u32 start_minor_hash, __u32 *next_hash)
{
	struct dx_hash_info hinfo;
	struct ext4_dir_entry_2 *de;
	struct dx_frame frames[EXT4_HTREE_LEVEL], *frame;
	struct inode *dir;
	ext4_lblk_t block;
	int count = 0;
	int ret, err;
	__u32 hashval;
	struct fscrypt_str tmp_str;

	dxtrace(printk(KERN_DEBUG "In htree_fill_tree, start hash: %x:%x\n",
		       start_hash, start_minor_hash));
	dir = file_inode(dir_file);
	if (!(ext4_test_inode_flag(dir, EXT4_INODE_INDEX))) {
		hinfo.hash_version = EXT4_SB(dir->i_sb)->s_def_hash_version;
		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 (ext4_has_inline_data(dir)) {
			int has_inline_data = 1;
			count = ext4_inlinedir_to_tree(dir_file, dir, 0,
						       &hinfo, start_hash,
						       start_minor_hash,
						       &has_inline_data);
			if (has_inline_data) {
				*next_hash = ~0;
				return count;
			}
		}
		count = htree_dirblock_to_tree(dir_file, dir, 0, &hinfo,
					       start_hash, start_minor_hash);
		*next_hash = ~0;
		return count;
	}
	hinfo.hash = start_hash;
	hinfo.minor_hash = 0;
	frame = dx_probe(NULL, dir, &hinfo, frames);
	if (IS_ERR(frame))
		return PTR_ERR(frame);

	/* Add '.' and '..' from the htree header */
	if (!start_hash && !start_minor_hash) {
		de = (struct ext4_dir_entry_2 *) frames[0].bh->b_data;
		tmp_str.name = de->name;
		tmp_str.len = de->name_len;
		err = ext4_htree_store_dirent(dir_file, 0, 0,
					      de, &tmp_str);
		if (err != 0)
			goto errout;
		count++;
	}
	if (start_hash < 2 || (start_hash ==2 && start_minor_hash==0)) {
		de = (struct ext4_dir_entry_2 *) frames[0].bh->b_data;
		de = ext4_next_entry(de, dir->i_sb->s_blocksize);
		tmp_str.name = de->name;
		tmp_str.len = de->name_len;
		err = ext4_htree_store_dirent(dir_file, 2, 0,
					      de, &tmp_str);
		if (err != 0)
			goto errout;
		count++;
	}

	while (1) {
		if (fatal_signal_pending(current)) {
			err = -ERESTARTSYS;
			goto errout;
		}
		cond_resched();
		block = dx_get_block(frame->at);
		ret = htree_dirblock_to_tree(dir_file, dir, block, &hinfo,
					     start_hash, start_minor_hash);
		if (ret < 0) {
			err = ret;
			goto errout;
		}
		count += ret;
		hashval = ~0;
		ret = ext4_htree_next_block(dir, HASH_NB_ALWAYS,
					    frame, frames, &hashval);
		*next_hash = hashval;
		if (ret < 0) {
			err = ret;
			goto errout;
		}
		/*
		 * Stop if:  (a) there are no more entries, or
		 * (b) we have inserted at least one entry and the
		 * next hash value is not a continuation
		 */
		if ((ret == 0) ||
		    (count && ((hashval & 1) == 0)))
			break;
	}
	dx_release(frames);
	dxtrace(printk(KERN_DEBUG "Fill tree: returned %d entries, "
		       "next hash: %x\n", count, *next_hash));
	return count;
errout:
	dx_release(frames);
	return (err);
}


static int ext4_cross_rename(struct inode *old_dir, struct dentry *old_dentry,
			     struct inode *new_dir, struct dentry *new_dentry)
{
	handle_t *handle = NULL;
	struct ext4_renament old = {
		.dir = old_dir,
		.dentry = old_dentry,
		.inode = d_inode(old_dentry),
	};
	struct ext4_renament new = {
		.dir = new_dir,
		.dentry = new_dentry,
		.inode = d_inode(new_dentry),
	};
	u8 new_file_type;
	int retval;
	struct timespec64 ctime;

	if ((ext4_test_inode_flag(new_dir, EXT4_INODE_PROJINHERIT) &&
	     !projid_eq(EXT4_I(new_dir)->i_projid,
			EXT4_I(old_dentry->d_inode)->i_projid)) ||
	    (ext4_test_inode_flag(old_dir, EXT4_INODE_PROJINHERIT) &&
	     !projid_eq(EXT4_I(old_dir)->i_projid,
			EXT4_I(new_dentry->d_inode)->i_projid)))
		return -EXDEV;

	retval = dquot_initialize(old.dir);
	if (retval)
		return retval;
	retval = dquot_initialize(new.dir);
	if (retval)
		return retval;

	old.bh = ext4_find_entry(old.dir, &old.dentry->d_name,
				 &old.de, &old.inlined);
	if (IS_ERR(old.bh))
		return PTR_ERR(old.bh);
	/*
	 *  Check for inode number is _not_ due to possible IO errors.
	 *  We might rmdir the source, keep it as pwd of some process
	 *  and merrily kill the link to whatever was created under the
	 *  same name. Goodbye sticky bit ;-<
	 */
	retval = -ENOENT;
	if (!old.bh || le32_to_cpu(old.de->inode) != old.inode->i_ino)
		goto end_rename;

	new.bh = ext4_find_entry(new.dir, &new.dentry->d_name,
				 &new.de, &new.inlined);
	if (IS_ERR(new.bh)) {
		retval = PTR_ERR(new.bh);
		new.bh = NULL;
		goto end_rename;
	}

	/* RENAME_EXCHANGE case: old *and* new must both exist */
	if (!new.bh || le32_to_cpu(new.de->inode) != new.inode->i_ino)
		goto end_rename;

	handle = ext4_journal_start(old.dir, EXT4_HT_DIR,
		(2 * EXT4_DATA_TRANS_BLOCKS(old.dir->i_sb) +
		 2 * EXT4_INDEX_EXTRA_TRANS_BLOCKS + 2));
	if (IS_ERR(handle)) {
		retval = PTR_ERR(handle);
		handle = NULL;
		goto end_rename;
	}

	if (IS_DIRSYNC(old.dir) || IS_DIRSYNC(new.dir))
		ext4_handle_sync(handle);

	if (S_ISDIR(old.inode->i_mode)) {
		old.is_dir = true;
		retval = ext4_rename_dir_prepare(handle, &old);
		if (retval)
			goto end_rename;
	}
	if (S_ISDIR(new.inode->i_mode)) {
		new.is_dir = true;
		retval = ext4_rename_dir_prepare(handle, &new);
		if (retval)
			goto end_rename;
	}

	/*
	 * Other than the special case of overwriting a directory, parents'
	 * nlink only needs to be modified if this is a cross directory rename.
	 */
	if (old.dir != new.dir && old.is_dir != new.is_dir) {
		old.dir_nlink_delta = old.is_dir ? -1 : 1;
		new.dir_nlink_delta = -old.dir_nlink_delta;
		retval = -EMLINK;
		if ((old.dir_nlink_delta > 0 && EXT4_DIR_LINK_MAX(old.dir)) ||
		    (new.dir_nlink_delta > 0 && EXT4_DIR_LINK_MAX(new.dir)))
			goto end_rename;
	}

	new_file_type = new.de->file_type;
	retval = ext4_setent(handle, &new, old.inode->i_ino, old.de->file_type);
	if (retval)
		goto end_rename;

	retval = ext4_setent(handle, &old, new.inode->i_ino, new_file_type);
	if (retval)
		goto end_rename;

	/*
	 * Like most other Unix systems, set the ctime for inodes on a
	 * rename.
	 */
	ctime = current_time(old.inode);
	old.inode->i_ctime = ctime;
	new.inode->i_ctime = ctime;
	retval = ext4_mark_inode_dirty(handle, old.inode);
	if (unlikely(retval))
		goto end_rename;
	retval = ext4_mark_inode_dirty(handle, new.inode);
	if (unlikely(retval))
		goto end_rename;

	if (old.dir_bh) {
		retval = ext4_rename_dir_finish(handle, &old, new.dir->i_ino);
		if (retval)
			goto end_rename;
	}
	if (new.dir_bh) {
		retval = ext4_rename_dir_finish(handle, &new, old.dir->i_ino);
		if (retval)
			goto end_rename;
	}
	ext4_update_dir_count(handle, &old);
	ext4_update_dir_count(handle, &new);
	retval = 0;

end_rename:
	brelse(old.dir_bh);
	brelse(new.dir_bh);
	brelse(old.bh);
	brelse(new.bh);
	if (handle)
		ext4_journal_stop(handle);
	return retval;
}


static struct ext4_dir_entry_tail *get_dirent_tail(struct inode *inode,
						   struct buffer_head *bh)
{
	struct ext4_dir_entry_tail *t;

#ifdef PARANOID
	struct ext4_dir_entry *d, *top;

	d = (struct ext4_dir_entry *)bh->b_data;
	top = (struct ext4_dir_entry *)(bh->b_data +
		(EXT4_BLOCK_SIZE(inode->i_sb) -
		 sizeof(struct ext4_dir_entry_tail)));
	while (d < top && d->rec_len)
		d = (struct ext4_dir_entry *)(((void *)d) +
		    le16_to_cpu(d->rec_len));

	if (d != top)
		return NULL;

	t = (struct ext4_dir_entry_tail *)d;
#else
	t = EXT4_DIRENT_TAIL(bh->b_data, EXT4_BLOCK_SIZE(inode->i_sb));
#endif

	if (t->det_reserved_zero1 ||
	    le16_to_cpu(t->det_rec_len) != sizeof(struct ext4_dir_entry_tail) ||
	    t->det_reserved_zero2 ||
	    t->det_reserved_ft != EXT4_FT_DIR_CSUM)
		return NULL;

	return t;
}


static int ext4_rename(struct inode *old_dir, struct dentry *old_dentry,
		       struct inode *new_dir, struct dentry *new_dentry,
		       unsigned int flags)
{
	handle_t *handle = NULL;
	struct ext4_renament old = {
		.dir = old_dir,
		.dentry = old_dentry,
		.inode = d_inode(old_dentry),
	};
	struct ext4_renament new = {
		.dir = new_dir,
		.dentry = new_dentry,
		.inode = d_inode(new_dentry),
	};
	int force_reread;
	int retval;
	struct inode *whiteout = NULL;
	int credits;
	u8 old_file_type;

	if (new.inode && new.inode->i_nlink == 0) {
		EXT4_ERROR_INODE(new.inode,
				 "target of rename is already freed");
		return -EFSCORRUPTED;
	}

	if ((ext4_test_inode_flag(new_dir, EXT4_INODE_PROJINHERIT)) &&
	    (!projid_eq(EXT4_I(new_dir)->i_projid,
			EXT4_I(old_dentry->d_inode)->i_projid)))
		return -EXDEV;

	retval = dquot_initialize(old.dir);
	if (retval)
		return retval;
	retval = dquot_initialize(new.dir);
	if (retval)
		return retval;

	/* Initialize quotas before so that eventual writes go
	 * in separate transaction */
	if (new.inode) {
		retval = dquot_initialize(new.inode);
		if (retval)
			return retval;
	}

	old.bh = ext4_find_entry(old.dir, &old.dentry->d_name, &old.de, NULL);
	if (IS_ERR(old.bh))
		return PTR_ERR(old.bh);
	/*
	 *  Check for inode number is _not_ due to possible IO errors.
	 *  We might rmdir the source, keep it as pwd of some process
	 *  and merrily kill the link to whatever was created under the
	 *  same name. Goodbye sticky bit ;-<
	 */
	retval = -ENOENT;
	if (!old.bh || le32_to_cpu(old.de->inode) != old.inode->i_ino)
		goto end_rename;

	new.bh = ext4_find_entry(new.dir, &new.dentry->d_name,
				 &new.de, &new.inlined);
	if (IS_ERR(new.bh)) {
		retval = PTR_ERR(new.bh);
		new.bh = NULL;
		goto end_rename;
	}
	if (new.bh) {
		if (!new.inode) {
			brelse(new.bh);
			new.bh = NULL;
		}
	}
	if (new.inode && !test_opt(new.dir->i_sb, NO_AUTO_DA_ALLOC))
		ext4_alloc_da_blocks(old.inode);

	credits = (2 * EXT4_DATA_TRANS_BLOCKS(old.dir->i_sb) +
		   EXT4_INDEX_EXTRA_TRANS_BLOCKS + 2);
	if (!(flags & RENAME_WHITEOUT)) {
		handle = ext4_journal_start(old.dir, EXT4_HT_DIR, credits);
		if (IS_ERR(handle)) {
			retval = PTR_ERR(handle);
			handle = NULL;
			goto end_rename;
		}
	} else {
		whiteout = ext4_whiteout_for_rename(&old, credits, &handle);
		if (IS_ERR(whiteout)) {
			retval = PTR_ERR(whiteout);
			whiteout = NULL;
			goto end_rename;
		}
	}

	if (IS_DIRSYNC(old.dir) || IS_DIRSYNC(new.dir))
		ext4_handle_sync(handle);

	if (S_ISDIR(old.inode->i_mode)) {
		if (new.inode) {
			retval = -ENOTEMPTY;
			if (!ext4_empty_dir(new.inode))
				goto end_rename;
		} else {
			retval = -EMLINK;
			if (new.dir != old.dir && EXT4_DIR_LINK_MAX(new.dir))
				goto end_rename;
		}
		retval = ext4_rename_dir_prepare(handle, &old);
		if (retval)
			goto end_rename;
	}
	/*
	 * If we're renaming a file within an inline_data dir and adding or
	 * setting the new dirent causes a conversion from inline_data to
	 * extents/blockmap, we need to force the dirent delete code to
	 * re-read the directory, or else we end up trying to delete a dirent
	 * from what is now the extent tree root (or a block map).
	 */
	force_reread = (new.dir->i_ino == old.dir->i_ino &&
			ext4_test_inode_flag(new.dir, EXT4_INODE_INLINE_DATA));

	old_file_type = old.de->file_type;
	if (whiteout) {
		/*
		 * Do this before adding a new entry, so the old entry is sure
		 * to be still pointing to the valid old entry.
		 */
		retval = ext4_setent(handle, &old, whiteout->i_ino,
				     EXT4_FT_CHRDEV);
		if (retval)
			goto end_rename;
		retval = ext4_mark_inode_dirty(handle, whiteout);
		if (unlikely(retval))
			goto end_rename;
	}
	if (!new.bh) {
		retval = ext4_add_entry(handle, new.dentry, old.inode);
		if (retval)
			goto end_rename;
	} else {
		retval = ext4_setent(handle, &new,
				     old.inode->i_ino, old_file_type);
		if (retval)
			goto end_rename;
	}
	if (force_reread)
		force_reread = !ext4_test_inode_flag(new.dir,
						     EXT4_INODE_INLINE_DATA);

	/*
	 * Like most other Unix systems, set the ctime for inodes on a
	 * rename.
	 */
	old.inode->i_ctime = current_time(old.inode);
	retval = ext4_mark_inode_dirty(handle, old.inode);
	if (unlikely(retval))
		goto end_rename;

	if (!whiteout) {
		/*
		 * ok, that's it
		 */
		ext4_rename_delete(handle, &old, force_reread);
	}

	if (new.inode) {
		ext4_dec_count(handle, new.inode);
		new.inode->i_ctime = current_time(new.inode);
	}
	old.dir->i_ctime = old.dir->i_mtime = current_time(old.dir);
	ext4_update_dx_flag(old.dir);
	if (old.dir_bh) {
		retval = ext4_rename_dir_finish(handle, &old, new.dir->i_ino);
		if (retval)
			goto end_rename;

		ext4_dec_count(handle, old.dir);
		if (new.inode) {
			/* checked ext4_empty_dir above, can't have another
			 * parent, ext4_dec_count() won't work for many-linked
			 * dirs */
			clear_nlink(new.inode);
		} else {
			ext4_inc_count(handle, new.dir);
			ext4_update_dx_flag(new.dir);
			retval = ext4_mark_inode_dirty(handle, new.dir);
			if (unlikely(retval))
				goto end_rename;
		}
	}
	retval = ext4_mark_inode_dirty(handle, old.dir);
	if (unlikely(retval))
		goto end_rename;
	if (new.inode) {
		retval = ext4_mark_inode_dirty(handle, new.inode);
		if (unlikely(retval))
			goto end_rename;
		if (!new.inode->i_nlink)
			ext4_orphan_add(handle, new.inode);
	}
	retval = 0;

end_rename:
	brelse(old.dir_bh);
	brelse(old.bh);
	brelse(new.bh);
	if (whiteout) {
		if (retval)
			drop_nlink(whiteout);
		unlock_new_inode(whiteout);
		iput(whiteout);
	}
	if (handle)
		ext4_journal_stop(handle);
	return retval;
}


void ext4_insert_dentry(struct inode *inode,
			struct ext4_dir_entry_2 *de,
			int buf_size,
			struct ext4_filename *fname)
{

	int nlen, rlen;

	nlen = EXT4_DIR_REC_LEN(de->name_len);
	rlen = ext4_rec_len_from_disk(de->rec_len, buf_size);
	if (de->inode) {
		struct ext4_dir_entry_2 *de1 =
			(struct ext4_dir_entry_2 *)((char *)de + nlen);
		de1->rec_len = ext4_rec_len_to_disk(rlen - nlen, buf_size);
		de->rec_len = ext4_rec_len_to_disk(nlen, buf_size);
		de = de1;
	}
	de->file_type = EXT4_FT_UNKNOWN;
	de->inode = cpu_to_le32(inode->i_ino);
	ext4_set_de_type(inode->i_sb, de, inode->i_mode);
	de->name_len = fname_len(fname);
	memcpy(de->name, fname_name(fname), fname_len(fname));
}


static struct buffer_head *ext4_get_first_dir_block(handle_t *handle,
					struct inode *inode,
					int *retval,
					struct ext4_dir_entry_2 **parent_de,
					int *inlined)
{
	struct buffer_head *bh;

	if (!ext4_has_inline_data(inode)) {
		/* The first directory block must not be a hole, so
		 * treat it as DIRENT_HTREE
		 */
		bh = ext4_read_dirblock(inode, 0, DIRENT_HTREE);
		if (IS_ERR(bh)) {
			*retval = PTR_ERR(bh);
			return NULL;
		}
		*parent_de = ext4_next_entry(
					(struct ext4_dir_entry_2 *)bh->b_data,
					inode->i_sb->s_blocksize);
		return bh;
	}

	*inlined = 1;
	return ext4_get_first_inline_block(inode, parent_de, retval);
}


static int ext4_rmdir(struct inode *dir, struct dentry *dentry)
{
	int retval;
	struct inode *inode;
	struct buffer_head *bh;
	struct ext4_dir_entry_2 *de;
	handle_t *handle = NULL;

	if (unlikely(ext4_forced_shutdown(EXT4_SB(dir->i_sb))))
		return -EIO;

	/* Initialize quotas before so that eventual writes go in
	 * separate transaction */
	retval = dquot_initialize(dir);
	if (retval)
		return retval;
	retval = dquot_initialize(d_inode(dentry));
	if (retval)
		return retval;

	retval = -ENOENT;
	bh = ext4_find_entry(dir, &dentry->d_name, &de, NULL);
	if (IS_ERR(bh))
		return PTR_ERR(bh);
	if (!bh)
		goto end_rmdir;

	inode = d_inode(dentry);

	retval = -EFSCORRUPTED;
	if (le32_to_cpu(de->inode) != inode->i_ino)
		goto end_rmdir;

	retval = -ENOTEMPTY;
	if (!ext4_empty_dir(inode))
		goto end_rmdir;

	handle = ext4_journal_start(dir, EXT4_HT_DIR,
				    EXT4_DATA_TRANS_BLOCKS(dir->i_sb));
	if (IS_ERR(handle)) {
		retval = PTR_ERR(handle);
		handle = NULL;
		goto end_rmdir;
	}

	if (IS_DIRSYNC(dir))
		ext4_handle_sync(handle);

	retval = ext4_delete_entry(handle, dir, de, bh);
	if (retval)
		goto end_rmdir;
	if (!EXT4_DIR_LINK_EMPTY(inode))
		ext4_warning_inode(inode,
			     "empty directory '%.*s' has too many links (%u)",
			     dentry->d_name.len, dentry->d_name.name,
			     inode->i_nlink);
	inode_inc_iversion(inode);
	clear_nlink(inode);
	/* There's no need to set i_disksize: the fact that i_nlink is
	 * zero will ensure that the right thing happens during any
	 * recovery. */
	inode->i_size = 0;
	ext4_orphan_add(handle, inode);
	inode->i_ctime = dir->i_ctime = dir->i_mtime = current_time(inode);
	retval = ext4_mark_inode_dirty(handle, inode);
	if (retval)
		goto end_rmdir;
	ext4_dec_count(handle, dir);
	ext4_update_dx_flag(dir);
	retval = ext4_mark_inode_dirty(handle, dir);

#ifdef 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))
		d_invalidate(dentry);
#endif

end_rmdir:
	brelse(bh);
	if (handle)
		ext4_journal_stop(handle);
	return retval;
}


static void dx_show_index(char * label, struct dx_entry *entries)
{
	int i, n = dx_get_count (entries);
	printk(KERN_DEBUG "%s index", label);
	for (i = 0; i < n; i++) {
		printk(KERN_CONT " %x->%lu",
		       i ? dx_get_hash(entries + i) : 0,
		       (unsigned long)dx_get_block(entries + i));
	}
	printk(KERN_CONT "\n");
}


int ext4_orphan_add(handle_t *handle, struct inode *inode)
{
	struct super_block *sb = inode->i_sb;
	struct ext4_sb_info *sbi = EXT4_SB(sb);
	struct ext4_iloc iloc;
	int err = 0, rc;
	bool dirty = false;

	if (!sbi->s_journal || is_bad_inode(inode))
		return 0;

	WARN_ON_ONCE(!(inode->i_state & (I_NEW | I_FREEING)) &&
		     !inode_is_locked(inode));
	/*
	 * Exit early if inode already is on orphan list. This is a big speedup
	 * since we don't have to contend on the global s_orphan_lock.
	 */
	if (!list_empty(&EXT4_I(inode)->i_orphan))
		return 0;

	/*
	 * Orphan handling is only valid for files with data blocks
	 * being truncated, or files being unlinked. Note that we either
	 * hold i_mutex, or the inode can not be referenced from outside,
	 * so i_nlink should not be bumped due to race
	 */
	J_ASSERT((S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
		  S_ISLNK(inode->i_mode)) || inode->i_nlink == 0);

	BUFFER_TRACE(sbi->s_sbh, "get_write_access");
	err = ext4_journal_get_write_access(handle, sbi->s_sbh);
	if (err)
		goto out;

	err = ext4_reserve_inode_write(handle, inode, &iloc);
	if (err)
		goto out;

	mutex_lock(&sbi->s_orphan_lock);
	/*
	 * Due to previous errors inode may be already a part of on-disk
	 * orphan list. If so skip on-disk list modification.
	 */
	if (!NEXT_ORPHAN(inode) || NEXT_ORPHAN(inode) >
	    (le32_to_cpu(sbi->s_es->s_inodes_count))) {
		/* Insert this inode at the head of the on-disk orphan list */
		NEXT_ORPHAN(inode) = le32_to_cpu(sbi->s_es->s_last_orphan);
		sbi->s_es->s_last_orphan = cpu_to_le32(inode->i_ino);
		dirty = true;
	}
	list_add(&EXT4_I(inode)->i_orphan, &sbi->s_orphan);
	mutex_unlock(&sbi->s_orphan_lock);

	if (dirty) {
		err = ext4_handle_dirty_super(handle, sb);
		rc = ext4_mark_iloc_dirty(handle, inode, &iloc);
		if (!err)
			err = rc;
		if (err) {
			/*
			 * We have to remove inode from in-memory list if
			 * addition to on disk orphan list failed. Stray orphan
			 * list entries can cause panics at unmount time.
			 */
			mutex_lock(&sbi->s_orphan_lock);
			list_del_init(&EXT4_I(inode)->i_orphan);
			mutex_unlock(&sbi->s_orphan_lock);
		}
	} else
		brelse(iloc.bh);

	jbd_debug(4, "superblock will point to %lu\n", inode->i_ino);
	jbd_debug(4, "orphan inode %lu will point to %d\n",
			inode->i_ino, NEXT_ORPHAN(inode));
out:
	ext4_std_error(sb, err);
	return err;
}

static int ext4_dx_csum_verify(struct inode *inode,
			       struct ext4_dir_entry *dirent);

#define ext4_read_dirblock(inode, block, type) \
	__ext4_read_dirblock((inode), (block), (type), __func__, __LINE__)

#define assert(test) J_ASSERT(test)

struct fake_dirent
{
	__le32 inode;
	__le16 rec_len;
	u8 name_len;
	u8 file_type;
}

struct dx_countlimit
{
	__le16 limit;
	__le16 count;
}

struct dx_entry
{
	__le32 hash;
	__le32 block;
}

struct dx_root
{
	struct fake_dirent dot;
	char dot_name[4];
	struct fake_dirent dotdot;
	char dotdot_name[4];
	struct dx_root_info
	{
		__le32 reserved_zero;
		u8 hash_version;
		u8 info_length; /* 8 */
		u8 indirect_levels;
		u8 unused_flags;
	}
	info;
	struct dx_entry	entries[];
}

struct dx_node
{
	struct fake_dirent fake;
	struct dx_entry	entries[];
}

struct dx_frame
{
	struct buffer_head *bh;
	struct dx_entry *entries;
	struct dx_entry *at;
}

struct dx_map_entry
{
	u32 hash;
	u16 offs;
	u16 size;
}

struct dx_tail {
	u32 dt_reserved;
	__le32 dt_checksum;	/* crc32c(uuid+inum+dirblock) */
}

static inline ext4_lblk_t dx_get_block(struct dx_entry *entry);

static void dx_set_block(struct dx_entry *entry, ext4_lblk_t value);

static inline unsigned dx_get_hash(struct dx_entry *entry);

static void dx_set_hash(struct dx_entry *entry, unsigned value);

static unsigned dx_get_count(struct dx_entry *entries);

static unsigned dx_get_limit(struct dx_entry *entries);

static void dx_set_count(struct dx_entry *entries, unsigned value);

static void dx_set_limit(struct dx_entry *entries, unsigned value);

static unsigned dx_root_limit(struct inode *dir, unsigned infosize);

static unsigned dx_node_limit(struct inode *dir);

static struct dx_frame *dx_probe(struct ext4_filename *fname,
				 struct inode *dir,
				 struct dx_hash_info *hinfo,
				 struct dx_frame *frame);

static void dx_release(struct dx_frame *frames);

static int dx_make_map(struct inode *dir, struct ext4_dir_entry_2 *de,
		       unsigned blocksize, struct dx_hash_info *hinfo,
		       struct dx_map_entry map[]);

static void dx_sort_map(struct dx_map_entry *map, unsigned count);

static struct ext4_dir_entry_2 *dx_move_dirents(char *from, char *to,
		struct dx_map_entry *offsets, int count, unsigned blocksize);

static struct ext4_dir_entry_2* dx_pack_dirents(char *base, unsigned blocksize);

static void dx_insert_block(struct dx_frame *frame,
					u32 hash, ext4_lblk_t block);

static int ext4_htree_next_block(struct inode *dir, __u32 hash,
				 struct dx_frame *frame,
				 struct dx_frame *frames,
				 __u32 *start_hash);

static struct buffer_head * ext4_dx_find_entry(struct inode *dir,
		struct ext4_filename *fname,
		struct ext4_dir_entry_2 **res_dir);

static int ext4_dx_add_entry(handle_t *handle, struct ext4_filename *fname,
			     struct inode *dir, struct inode *inode);

#define warn_no_space_for_csum(inode)					\
	__warn_no_space_for_csum((inode), __func__, __LINE__)

struct stats
{
	unsigned names;
	unsigned space;
	unsigned bcount;
}


void ext4_fname_setup_ci_filename(struct inode *dir, const struct qstr *iname,
				  struct fscrypt_str *cf_name)
{
	int len;

	if (!IS_CASEFOLDED(dir) || !EXT4_SB(dir->i_sb)->s_encoding) {
		cf_name->name = NULL;
		return;
	}

	cf_name->name = kmalloc(EXT4_NAME_LEN, GFP_NOFS);
	if (!cf_name->name)
		return;

	len = utf8_casefold(EXT4_SB(dir->i_sb)->s_encoding,
			    iname, cf_name->name,
			    EXT4_NAME_LEN);
	if (len <= 0) {
		kfree(cf_name->name);
		cf_name->name = NULL;
		return;
	}
	cf_name->len = (unsigned) len;

}


static inline int search_dirblock(struct buffer_head *bh,
				  struct inode *dir,
				  struct ext4_filename *fname,
				  unsigned int offset,
				  struct ext4_dir_entry_2 **res_dir)
{
	return ext4_search_dir(bh, bh->b_data, dir->i_sb->s_blocksize, dir,
			       fname, offset, res_dir);
}


static struct inode *ext4_whiteout_for_rename(struct ext4_renament *ent,
					      int credits, handle_t **h)
{
	struct inode *wh;
	handle_t *handle;
	int retries = 0;

	/*
	 * for inode block, sb block, group summaries,
	 * and inode bitmap
	 */
	credits += (EXT4_MAXQUOTAS_TRANS_BLOCKS(ent->dir->i_sb) +
		    EXT4_XATTR_TRANS_BLOCKS + 4);
retry:
	wh = ext4_new_inode_start_handle(ent->dir, S_IFCHR | WHITEOUT_MODE,
					 &ent->dentry->d_name, 0, NULL,
					 EXT4_HT_DIR, credits);

	handle = ext4_journal_current_handle();
	if (IS_ERR(wh)) {
		if (handle)
			ext4_journal_stop(handle);
		if (PTR_ERR(wh) == -ENOSPC &&
		    ext4_should_retry_alloc(ent->dir->i_sb, &retries))
			goto retry;
	} else {
		*h = handle;
		init_special_inode(wh, wh->i_mode, WHITEOUT_DEV);
		wh->i_op = &ext4_special_inode_operations;
	}
	return wh;
}


static void dx_release(struct dx_frame *frames)
{
	struct dx_root_info *info;
	int i;
	unsigned int indirect_levels;

	if (frames[0].bh == NULL)
		return;

	info = &((struct dx_root *)frames[0].bh->b_data)->info;
	/* save local copy, "info" may be freed after brelse() */
	indirect_levels = info->indirect_levels;
	for (i = 0; i <= indirect_levels; i++) {
		if (frames[i].bh == NULL)
			break;
		brelse(frames[i].bh);
		frames[i].bh = NULL;
	}
}


static int ext4_dx_csum_verify(struct inode *inode,
			       struct ext4_dir_entry *dirent)
{
	struct dx_countlimit *c;
	struct dx_tail *t;
	int count_offset, limit, count;

	if (!ext4_has_metadata_csum(inode->i_sb))
		return 1;

	c = get_dx_countlimit(inode, dirent, &count_offset);
	if (!c) {
		EXT4_ERROR_INODE(inode, "dir seems corrupt?  Run e2fsck -D.");
		return 0;
	}
	limit = le16_to_cpu(c->limit);
	count = le16_to_cpu(c->count);
	if (count_offset + (limit * sizeof(struct dx_entry)) >
	    EXT4_BLOCK_SIZE(inode->i_sb) - sizeof(struct dx_tail)) {
		warn_no_space_for_csum(inode);
		return 0;
	}
	t = (struct dx_tail *)(((struct dx_entry *)c) + limit);

	if (t->dt_checksum != ext4_dx_csum(inode, dirent, count_offset,
					    count, t))
		return 0;
	return 1;
}


ext4_next_entry(struct ext4_dir_entry_2 *p, unsigned long blocksize)
{
	return (struct ext4_dir_entry_2 *)((char *)p +
		ext4_rec_len_from_disk(p->rec_len, blocksize));
}


static int ext4_delete_entry(handle_t *handle,
			     struct inode *dir,
			     struct ext4_dir_entry_2 *de_del,
			     struct buffer_head *bh)
{
	int err, csum_size = 0;

	if (ext4_has_inline_data(dir)) {
		int has_inline_data = 1;
		err = ext4_delete_inline_entry(handle, dir, de_del, bh,
					       &has_inline_data);
		if (has_inline_data)
			return err;
	}

	if (ext4_has_metadata_csum(dir->i_sb))
		csum_size = sizeof(struct ext4_dir_entry_tail);

	BUFFER_TRACE(bh, "get_write_access");
	err = ext4_journal_get_write_access(handle, bh);
	if (unlikely(err))
		goto out;

	err = ext4_generic_delete_entry(handle, dir, de_del,
					bh, bh->b_data,
					dir->i_sb->s_blocksize, csum_size);
	if (err)
		goto out;

	BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
	err = ext4_handle_dirty_dirblock(handle, dir, bh);
	if (unlikely(err))
		goto out;

	return 0;
out:
	if (err != -ENOENT)
		ext4_std_error(dir->i_sb, err);
	return err;
}


static inline void dx_set_hash(struct dx_entry *entry, unsigned value)
{
	entry->hash = cpu_to_le32(value);
}


static void ext4_dec_count(handle_t *handle, struct inode *inode)
{
	if (!S_ISDIR(inode->i_mode) || inode->i_nlink > 2)
		drop_nlink(inode);
}


static int ext4_add_nondir(handle_t *handle,
		struct dentry *dentry, struct inode **inodep)
{
	struct inode *dir = d_inode(dentry->d_parent);
	struct inode *inode = *inodep;
	int err = ext4_add_entry(handle, dentry, inode);
	if (!err) {
		err = ext4_mark_inode_dirty(handle, inode);
		if (IS_DIRSYNC(dir))
			ext4_handle_sync(handle);
		d_instantiate_new(dentry, inode);
		*inodep = NULL;
		return err;
	}
	drop_nlink(inode);
	ext4_orphan_add(handle, inode);
	unlock_new_inode(inode);
	return err;
}


static int dx_make_map(struct inode *dir, struct ext4_dir_entry_2 *de,
		       unsigned blocksize, struct dx_hash_info *hinfo,
		       struct dx_map_entry *map_tail)
{
	int count = 0;
	char *base = (char *) de;
	struct dx_hash_info h = *hinfo;

	while ((char *) de < base + blocksize) {
		if (de->name_len && de->inode) {
			ext4fs_dirhash(dir, de->name, de->name_len, &h);
			map_tail--;
			map_tail->hash = h.hash;
			map_tail->offs = ((char *) de - base)>>2;
			map_tail->size = le16_to_cpu(de->rec_len);
			count++;
			cond_resched();
		}
		/* XXX: do we need to check rec_len == 0 case? -Chris */
		de = ext4_next_entry(de, blocksize);
	}
	return count;
}


static struct buffer_head *ext4_append(handle_t *handle,
					struct inode *inode,
					ext4_lblk_t *block)
{
	struct buffer_head *bh;
	int err;

	if (unlikely(EXT4_SB(inode->i_sb)->s_max_dir_size_kb &&
		     ((inode->i_size >> 10) >=
		      EXT4_SB(inode->i_sb)->s_max_dir_size_kb)))
		return ERR_PTR(-ENOSPC);

	*block = inode->i_size >> inode->i_sb->s_blocksize_bits;

	bh = ext4_bread(handle, inode, *block, EXT4_GET_BLOCKS_CREATE);
	if (IS_ERR(bh))
		return bh;
	inode->i_size += inode->i_sb->s_blocksize;
	EXT4_I(inode)->i_disksize = inode->i_size;
	BUFFER_TRACE(bh, "get_write_access");
	err = ext4_journal_get_write_access(handle, bh);
	if (err) {
		brelse(bh);
		ext4_std_error(inode->i_sb, err);
		return ERR_PTR(err);
	}
	return bh;
}


static int add_dirent_to_buf(handle_t *handle, struct ext4_filename *fname,
			     struct inode *dir,
			     struct inode *inode, struct ext4_dir_entry_2 *de,
			     struct buffer_head *bh)
{
	unsigned int	blocksize = dir->i_sb->s_blocksize;
	int		csum_size = 0;
	int		err, err2;

	if (ext4_has_metadata_csum(inode->i_sb))
		csum_size = sizeof(struct ext4_dir_entry_tail);

	if (!de) {
		err = ext4_find_dest_de(dir, inode, bh, bh->b_data,
					blocksize - csum_size, fname, &de);
		if (err)
			return err;
	}
	BUFFER_TRACE(bh, "get_write_access");
	err = ext4_journal_get_write_access(handle, bh);
	if (err) {
		ext4_std_error(dir->i_sb, err);
		return err;
	}

	/* By now the buffer is marked for journaling */
	ext4_insert_dentry(inode, de, blocksize, fname);

	/*
	 * XXX shouldn't update any times until successful
	 * completion of syscall, but too many callers depend
	 * on this.
	 *
	 * XXX similarly, too many callers depend on
	 * ext4_new_inode() setting the times, but error
	 * recovery deletes the inode, so the worst that can
	 * happen is that the times are slightly out of date
	 * and/or different from the directory change time.
	 */
	dir->i_mtime = dir->i_ctime = current_time(dir);
	ext4_update_dx_flag(dir);
	inode_inc_iversion(dir);
	err2 = ext4_mark_inode_dirty(handle, dir);
	BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
	err = ext4_handle_dirty_dirblock(handle, dir, bh);
	if (err)
		ext4_std_error(dir->i_sb, err);
	return err ? err : err2;
}


static int ext4_rename2(struct inode *old_dir, struct dentry *old_dentry,
			struct inode *new_dir, struct dentry *new_dentry,
			unsigned int flags)
{
	int err;

	if (unlikely(ext4_forced_shutdown(EXT4_SB(old_dir->i_sb))))
		return -EIO;

	if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE | RENAME_WHITEOUT))
		return -EINVAL;

	err = fscrypt_prepare_rename(old_dir, old_dentry, new_dir, new_dentry,
				     flags);
	if (err)
		return err;

	if (flags & RENAME_EXCHANGE) {
		return ext4_cross_rename(old_dir, old_dentry,
					 new_dir, new_dentry);
	}

	return ext4_rename(old_dir, old_dentry, new_dir, new_dentry, flags);
}


static int make_indexed_dir(handle_t *handle, struct ext4_filename *fname,
			    struct inode *dir,
			    struct inode *inode, struct buffer_head *bh)
{
	struct buffer_head *bh2;
	struct dx_root	*root;
	struct dx_frame	frames[EXT4_HTREE_LEVEL], *frame;
	struct dx_entry *entries;
	struct ext4_dir_entry_2	*de, *de2;
	char		*data2, *top;
	unsigned	len;
	int		retval;
	unsigned	blocksize;
	ext4_lblk_t  block;
	struct fake_dirent *fde;
	int csum_size = 0;

	if (ext4_has_metadata_csum(inode->i_sb))
		csum_size = sizeof(struct ext4_dir_entry_tail);

	blocksize =  dir->i_sb->s_blocksize;
	dxtrace(printk(KERN_DEBUG "Creating index: inode %lu\n", dir->i_ino));
	BUFFER_TRACE(bh, "get_write_access");
	retval = ext4_journal_get_write_access(handle, bh);
	if (retval) {
		ext4_std_error(dir->i_sb, retval);
		brelse(bh);
		return retval;
	}
	root = (struct dx_root *) bh->b_data;

	/* The 0th block becomes the root, move the dirents out */
	fde = &root->dotdot;
	de = (struct ext4_dir_entry_2 *)((char *)fde +
		ext4_rec_len_from_disk(fde->rec_len, blocksize));
	if ((char *) de >= (((char *) root) + blocksize)) {
		EXT4_ERROR_INODE(dir, "invalid rec_len for '..'");
		brelse(bh);
		return -EFSCORRUPTED;
	}
	len = ((char *) root) + (blocksize - csum_size) - (char *) de;

	/* Allocate new block for the 0th block's dirents */
	bh2 = ext4_append(handle, dir, &block);
	if (IS_ERR(bh2)) {
		brelse(bh);
		return PTR_ERR(bh2);
	}
	ext4_set_inode_flag(dir, EXT4_INODE_INDEX);
	data2 = bh2->b_data;

	memcpy(data2, de, len);
	de = (struct ext4_dir_entry_2 *) data2;
	top = data2 + len;
	while ((char *)(de2 = ext4_next_entry(de, blocksize)) < top)
		de = de2;
	de->rec_len = ext4_rec_len_to_disk(data2 + (blocksize - csum_size) -
					   (char *) de, blocksize);

	if (csum_size)
		ext4_initialize_dirent_tail(bh2, blocksize);

	/* Initialize the root; the dot dirents already exist */
	de = (struct ext4_dir_entry_2 *) (&root->dotdot);
	de->rec_len = ext4_rec_len_to_disk(blocksize - EXT4_DIR_REC_LEN(2),
					   blocksize);
	memset (&root->info, 0, sizeof(root->info));
	root->info.info_length = sizeof(root->info);
	root->info.hash_version = EXT4_SB(dir->i_sb)->s_def_hash_version;
	entries = root->entries;
	dx_set_block(entries, 1);
	dx_set_count(entries, 1);
	dx_set_limit(entries, dx_root_limit(dir, sizeof(root->info)));

	/* Initialize as for dx_probe */
	fname->hinfo.hash_version = root->info.hash_version;
	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;
	ext4fs_dirhash(dir, fname_name(fname), fname_len(fname), &fname->hinfo);

	memset(frames, 0, sizeof(frames));
	frame = frames;
	frame->entries = entries;
	frame->at = entries;
	frame->bh = bh;

	retval = ext4_handle_dirty_dx_node(handle, dir, frame->bh);
	if (retval)
		goto out_frames;
	retval = ext4_handle_dirty_dirblock(handle, dir, bh2);
	if (retval)
		goto out_frames;

	de = do_split(handle,dir, &bh2, frame, &fname->hinfo);
	if (IS_ERR(de)) {
		retval = PTR_ERR(de);
		goto out_frames;
	}

	retval = add_dirent_to_buf(handle, fname, dir, inode, de, bh2);
out_frames:
	/*
	 * Even if the block split failed, we have to properly write
	 * out all the changes we did so far. Otherwise we can end up
	 * with corrupted filesystem.
	 */
	if (retval)
		ext4_mark_inode_dirty(handle, dir);
	dx_release(frames);
	brelse(bh2);
	return retval;
}


static struct dentry *ext4_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
{
	struct inode *inode;
	struct ext4_dir_entry_2 *de;
	struct buffer_head *bh;

	if (dentry->d_name.len > EXT4_NAME_LEN)
		return ERR_PTR(-ENAMETOOLONG);

	bh = ext4_lookup_entry(dir, dentry, &de);
	if (IS_ERR(bh))
		return ERR_CAST(bh);
	inode = NULL;
	if (bh) {
		__u32 ino = le32_to_cpu(de->inode);
		brelse(bh);
		if (!ext4_valid_inum(dir->i_sb, ino)) {
			EXT4_ERROR_INODE(dir, "bad inode number: %u", ino);
			return ERR_PTR(-EFSCORRUPTED);
		}
		if (unlikely(ino == dir->i_ino)) {
			EXT4_ERROR_INODE(dir, "'%pd' linked to parent dir",
					 dentry);
			return ERR_PTR(-EFSCORRUPTED);
		}
		inode = ext4_iget(dir->i_sb, ino, EXT4_IGET_NORMAL);
		if (inode == ERR_PTR(-ESTALE)) {
			EXT4_ERROR_INODE(dir,
					 "deleted inode referenced: %u",
					 ino);
			return ERR_PTR(-EFSCORRUPTED);
		}
		if (!IS_ERR(inode) && IS_ENCRYPTED(dir) &&
		    (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode)) &&
		    !fscrypt_has_permitted_context(dir, inode)) {
			ext4_warning(inode->i_sb,
				     "Inconsistent encryption contexts: %lu/%lu",
				     dir->i_ino, inode->i_ino);
			iput(inode);
			return ERR_PTR(-EPERM);
		}
	}

#ifdef CONFIG_UNICODE
	if (!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
		 * from being cached.
		 */
		return NULL;
	}
#endif
	return d_splice_alias(inode, dentry);
}


int ext4_ci_compare(const struct inode *parent, const struct qstr *name,
		    const struct qstr *entry, bool quick)
{
	const struct ext4_sb_info *sbi = EXT4_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 (ext4_has_strict_mode(sbi))
			return -EINVAL;

		if (name->len != entry->len)
			return 1;

		return !!memcmp(name->name, entry->name, name->len);
	}

	return ret;
}


static int ext4_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
{
	handle_t *handle;
	struct inode *inode;
	int err, err2 = 0, credits, retries = 0;

	if (EXT4_DIR_LINK_MAX(dir))
		return -EMLINK;

	err = dquot_initialize(dir);
	if (err)
		return err;

	credits = (EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
		   EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3);
retry:
	inode = ext4_new_inode_start_handle(dir, S_IFDIR | mode,
					    &dentry->d_name,
					    0, NULL, EXT4_HT_DIR, credits);
	handle = ext4_journal_current_handle();
	err = PTR_ERR(inode);
	if (IS_ERR(inode))
		goto out_stop;

	inode->i_op = &ext4_dir_inode_operations;
	inode->i_fop = &ext4_dir_operations;
	err = ext4_init_new_dir(handle, dir, inode);
	if (err)
		goto out_clear_inode;
	err = ext4_mark_inode_dirty(handle, inode);
	if (!err)
		err = ext4_add_entry(handle, dentry, inode);
	if (err) {
out_clear_inode:
		clear_nlink(inode);
		ext4_orphan_add(handle, inode);
		unlock_new_inode(inode);
		err2 = ext4_mark_inode_dirty(handle, inode);
		if (unlikely(err2))
			err = err2;
		ext4_journal_stop(handle);
		iput(inode);
		goto out_retry;
	}
	ext4_inc_count(handle, dir);
	ext4_update_dx_flag(dir);
	err = ext4_mark_inode_dirty(handle, dir);
	if (err)
		goto out_clear_inode;
	d_instantiate_new(dentry, inode);
	if (IS_DIRSYNC(dir))
		ext4_handle_sync(handle);

out_stop:
	if (handle)
		ext4_journal_stop(handle);
out_retry:
	if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
		goto retry;
	return err;
}


static struct stats dx_show_leaf(struct inode *dir,
				struct dx_hash_info *hinfo,
				struct ext4_dir_entry_2 *de,
				int size, int show_names)
{
	unsigned names = 0, space = 0;
	char *base = (char *) de;
	struct dx_hash_info h = *hinfo;

	printk("names: ");
	while ((char *) de < base + size)
	{
		if (de->inode)
		{
			if (show_names)
			{
#ifdef CONFIG_FS_ENCRYPTION
				int len;
				char *name;
				struct fscrypt_str fname_crypto_str =
					FSTR_INIT(NULL, 0);
				int res = 0;

				name  = de->name;
				len = de->name_len;
				if (IS_ENCRYPTED(dir))
					res = fscrypt_get_encryption_info(dir);
				if (res) {
					printk(KERN_WARNING "Error setting up"
					       " fname crypto: %d\n", res);
				}
				if (!fscrypt_has_encryption_key(dir)) {
					/* Directory is not encrypted */
					ext4fs_dirhash(dir, de->name,
						de->name_len, &h);
					printk("%*.s:(U)%x.%u ", len,
					       name, h.hash,
					       (unsigned) ((char *) de
							   - base));
				} else {
					struct fscrypt_str de_name =
						FSTR_INIT(name, len);

					/* Directory is encrypted */
					res = fscrypt_fname_alloc_buffer(
						dir, len,
						&fname_crypto_str);
					if (res)
						printk(KERN_WARNING "Error "
							"allocating crypto "
							"buffer--skipping "
							"crypto\n");
					res = fscrypt_fname_disk_to_usr(dir,
						0, 0, &de_name,
						&fname_crypto_str);
					if (res) {
						printk(KERN_WARNING "Error "
							"converting filename "
							"from disk to usr"
							"\n");
						name = "??";
						len = 2;
					} else {
						name = fname_crypto_str.name;
						len = fname_crypto_str.len;
					}
					ext4fs_dirhash(dir, de->name,
						       de->name_len, &h);
					printk("%*.s:(E)%x.%u ", len, name,
					       h.hash, (unsigned) ((char *) de
								   - base));
					fscrypt_fname_free_buffer(
							&fname_crypto_str);
				}
#else
				int len = de->name_len;
				char *name = de->name;
				ext4fs_dirhash(dir, de->name, de->name_len, &h);
				printk("%*.s:%x.%u ", len, name, h.hash,
				       (unsigned) ((char *) de - base));
#endif
			}
			space += EXT4_DIR_REC_LEN(de->name_len);
			names++;
		}
		de = ext4_next_entry(de, size);
	}
	printk(KERN_CONT "(%i)\n", names);
	return (struct stats) { names, space, 1 };
}


static void dx_insert_block(struct dx_frame *frame, u32 hash, ext4_lblk_t block)
{
	struct dx_entry *entries = frame->entries;
	struct dx_entry *old = frame->at, *new = old + 1;
	int count = dx_get_count(entries);

	assert(count < dx_get_limit(entries));
	assert(old < entries + count);
	memmove(new + 1, new, (char *)(entries + count) - (char *)(new));
	dx_set_hash(new, hash);
	dx_set_block(new, block);
	dx_set_count(entries, count + 1);
}


static __le32 ext4_dx_csum(struct inode *inode, struct ext4_dir_entry *dirent,
			   int count_offset, int count, struct dx_tail *t)
{
	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
	struct ext4_inode_info *ei = EXT4_I(inode);
	__u32 csum;
	int size;
	__u32 dummy_csum = 0;
	int offset = offsetof(struct dx_tail, dt_checksum);

	size = count_offset + (count * sizeof(struct dx_entry));
	csum = ext4_chksum(sbi, ei->i_csum_seed, (__u8 *)dirent, size);
	csum = ext4_chksum(sbi, csum, (__u8 *)t, offset);
	csum = ext4_chksum(sbi, csum, (__u8 *)&dummy_csum, sizeof(dummy_csum));

	return cpu_to_le32(csum);
}


static inline unsigned dx_get_limit(struct dx_entry *entries)
{
	return le16_to_cpu(((struct dx_countlimit *) entries)->limit);
}


static inline void dx_set_limit(struct dx_entry *entries, unsigned value)
{
	((struct dx_countlimit *) entries)->limit = cpu_to_le16(value);
}


static int ext4_setent(handle_t *handle, struct ext4_renament *ent,
		       unsigned ino, unsigned file_type)
{
	int retval, retval2;

	BUFFER_TRACE(ent->bh, "get write access");
	retval = ext4_journal_get_write_access(handle, ent->bh);
	if (retval)
		return retval;
	ent->de->inode = cpu_to_le32(ino);
	if (ext4_has_feature_filetype(ent->dir->i_sb))
		ent->de->file_type = file_type;
	inode_inc_iversion(ent->dir);
	ent->dir->i_ctime = ent->dir->i_mtime =
		current_time(ent->dir);
	retval = ext4_mark_inode_dirty(handle, ent->dir);
	BUFFER_TRACE(ent->bh, "call ext4_handle_dirty_metadata");
	if (!ent->inlined) {
		retval2 = ext4_handle_dirty_dirblock(handle, ent->dir, ent->bh);
		if (unlikely(retval2)) {
			ext4_std_error(ent->dir->i_sb, retval2);
			return retval2;
		}
	}
	brelse(ent->bh);
	ent->bh = NULL;

	return retval;
}


static inline unsigned dx_node_limit(struct inode *dir)
{
	unsigned entry_space = dir->i_sb->s_blocksize - EXT4_DIR_REC_LEN(0);

	if (ext4_has_metadata_csum(dir->i_sb))
		entry_space -= sizeof(struct dx_tail);
	return entry_space / sizeof(struct dx_entry);
}


static struct buffer_head * ext4_dx_find_entry(struct inode *dir,
			struct ext4_filename *fname,
			struct ext4_dir_entry_2 **res_dir)
{
	struct super_block * sb = dir->i_sb;
	struct dx_frame frames[EXT4_HTREE_LEVEL], *frame;
	struct buffer_head *bh;
	ext4_lblk_t block;
	int retval;

#ifdef CONFIG_FS_ENCRYPTION
	*res_dir = NULL;
#endif
	frame = dx_probe(fname, dir, NULL, frames);
	if (IS_ERR(frame))
		return (struct buffer_head *) frame;
	do {
		block = dx_get_block(frame->at);
		bh = ext4_read_dirblock(dir, block, DIRENT_HTREE);
		if (IS_ERR(bh))
			goto errout;

		retval = search_dirblock(bh, dir, fname,
					 block << EXT4_BLOCK_SIZE_BITS(sb),
					 res_dir);
		if (retval == 1)
			goto success;
		brelse(bh);
		if (retval == -1) {
			bh = ERR_PTR(ERR_BAD_DX_DIR);
			goto errout;
		}

		/* Check to see if we should continue to search */
		retval = ext4_htree_next_block(dir, fname->hinfo.hash, frame,
					       frames, NULL);
		if (retval < 0) {
			ext4_warning_inode(dir,
				"error %d reading directory index block",
				retval);
			bh = ERR_PTR(retval);
			goto errout;
		}
	} while (retval == 1);

	bh = NULL;
errout:
	dxtrace(printk(KERN_DEBUG "%s not found\n", fname->usr_fname->name));
success:
	dx_release(frames);
	return bh;
}

static int ext4_dx_csum_verify(struct inode *inode,
			       struct ext4_dir_entry *dirent);

typedef enum {
	EITHER, INDEX, DIRENT, DIRENT_HTREE
} dirblock_type_t;

#define ext4_read_dirblock(inode, block, type) \
	__ext4_read_dirblock((inode), (block), (type), __func__, __LINE__)

#define dxtrace(command) command

#define dxtrace(command)

struct fake_dirent
{
	__le32 inode;
	__le16 rec_len;
	u8 name_len;
	u8 file_type;
}

struct dx_countlimit
{
	__le16 limit;
	__le16 count;
}

struct dx_entry
{
	__le32 hash;
	__le32 block;
}

struct dx_root
{
	struct fake_dirent dot;
	char dot_name[4];
	struct fake_dirent dotdot;
	char dotdot_name[4];
	struct dx_root_info
	{
		__le32 reserved_zero;
		u8 hash_version;
		u8 info_length; /* 8 */
		u8 indirect_levels;
		u8 unused_flags;
	}
	info;
	struct dx_entry	entries[];
}

struct dx_node
{
	struct fake_dirent fake;
	struct dx_entry	entries[];
}

struct dx_frame
{
	struct buffer_head *bh;
	struct dx_entry *entries;
	struct dx_entry *at;
}

struct dx_map_entry
{
	u32 hash;
	u16 offs;
	u16 size;
}

struct dx_tail {
	u32 dt_reserved;
	__le32 dt_checksum;	/* crc32c(uuid+inum+dirblock) */
}

static inline ext4_lblk_t dx_get_block(struct dx_entry *entry);

static void dx_set_block(struct dx_entry *entry, ext4_lblk_t value);

static inline unsigned dx_get_hash(struct dx_entry *entry);

static void dx_set_hash(struct dx_entry *entry, unsigned value);

static unsigned dx_get_count(struct dx_entry *entries);

static unsigned dx_get_limit(struct dx_entry *entries);

static void dx_set_count(struct dx_entry *entries, unsigned value);

static void dx_set_limit(struct dx_entry *entries, unsigned value);

static unsigned dx_root_limit(struct inode *dir, unsigned infosize);

static unsigned dx_node_limit(struct inode *dir);

static struct dx_frame *dx_probe(struct ext4_filename *fname,
				 struct inode *dir,
				 struct dx_hash_info *hinfo,
				 struct dx_frame *frame);

static void dx_release(struct dx_frame *frames);

static int dx_make_map(struct inode *dir, struct ext4_dir_entry_2 *de,
		       unsigned blocksize, struct dx_hash_info *hinfo,
		       struct dx_map_entry map[]);

static void dx_sort_map(struct dx_map_entry *map, unsigned count);

static struct ext4_dir_entry_2 *dx_move_dirents(char *from, char *to,
		struct dx_map_entry *offsets, int count, unsigned blocksize);

static struct ext4_dir_entry_2* dx_pack_dirents(char *base, unsigned blocksize);

static void dx_insert_block(struct dx_frame *frame,
					u32 hash, ext4_lblk_t block);

static int ext4_htree_next_block(struct inode *dir, __u32 hash,
				 struct dx_frame *frame,
				 struct dx_frame *frames,
				 __u32 *start_hash);

static struct buffer_head * ext4_dx_find_entry(struct inode *dir,
		struct ext4_filename *fname,
		struct ext4_dir_entry_2 **res_dir);

static int ext4_dx_add_entry(handle_t *handle, struct ext4_filename *fname,
			     struct inode *dir, struct inode *inode);


static inline unsigned dx_root_limit(struct inode *dir, unsigned infosize)
{
	unsigned entry_space = dir->i_sb->s_blocksize - EXT4_DIR_REC_LEN(1) -
		EXT4_DIR_REC_LEN(2) - infosize;

	if (ext4_has_metadata_csum(dir->i_sb))
		entry_space -= sizeof(struct dx_tail);
	return entry_space / sizeof(struct dx_entry);
}


static void __warn_no_space_for_csum(struct inode *inode, const char *func,
				     unsigned int line)
{
	__ext4_warning_inode(inode, func, line,
		"No space for directory leaf checksum. Please run e2fsck -D.");
}


static inline unsigned dx_get_hash(struct dx_entry *entry)
{
	return le32_to_cpu(entry->hash);
}


static struct buffer_head *ext4_find_entry(struct inode *dir,
					   const struct qstr *d_name,
					   struct ext4_dir_entry_2 **res_dir,
					   int *inlined)
{
	int err;
	struct ext4_filename fname;
	struct buffer_head *bh;

	err = ext4_fname_setup_filename(dir, d_name, 1, &fname);
	if (err == -ENOENT)
		return NULL;
	if (err)
		return ERR_PTR(err);

	bh = __ext4_find_entry(dir, &fname, res_dir, inlined);

	ext4_fname_free_filename(&fname);
	return bh;
}


static struct ext4_dir_entry_2* dx_pack_dirents(char *base, unsigned blocksize)
{
	struct ext4_dir_entry_2 *next, *to, *prev, *de = (struct ext4_dir_entry_2 *) base;
	unsigned rec_len = 0;

	prev = to = de;
	while ((char*)de < base + blocksize) {
		next = ext4_next_entry(de, blocksize);
		if (de->inode && de->name_len) {
			rec_len = EXT4_DIR_REC_LEN(de->name_len);
			if (de > to)
				memmove(to, de, rec_len);
			to->rec_len = ext4_rec_len_to_disk(rec_len, blocksize);
			prev = to;
			to = (struct ext4_dir_entry_2 *) (((char *) to) + rec_len);
		}
		de = next;
	}
	return prev;
}


void ext4_initialize_dirent_tail(struct buffer_head *bh,
				 unsigned int blocksize)
{
	struct ext4_dir_entry_tail *t = EXT4_DIRENT_TAIL(bh->b_data, blocksize);

	memset(t, 0, sizeof(struct ext4_dir_entry_tail));
	t->det_rec_len = ext4_rec_len_to_disk(
			sizeof(struct ext4_dir_entry_tail), blocksize);
	t->det_reserved_ft = EXT4_FT_DIR_CSUM;
}


static int ext4_symlink(struct inode *dir,
			struct dentry *dentry, const char *symname)
{
	handle_t *handle;
	struct inode *inode;
	int err, len = strlen(symname);
	int credits;
	struct fscrypt_str disk_link;

	if (unlikely(ext4_forced_shutdown(EXT4_SB(dir->i_sb))))
		return -EIO;

	err = fscrypt_prepare_symlink(dir, symname, len, dir->i_sb->s_blocksize,
				      &disk_link);
	if (err)
		return err;

	err = dquot_initialize(dir);
	if (err)
		return err;

	if ((disk_link.len > EXT4_N_BLOCKS * 4)) {
		/*
		 * For non-fast symlinks, we just allocate inode and put it on
		 * orphan list in the first transaction => we need bitmap,
		 * group descriptor, sb, inode block, quota blocks, and
		 * possibly selinux xattr blocks.
		 */
		credits = 4 + EXT4_MAXQUOTAS_INIT_BLOCKS(dir->i_sb) +
			  EXT4_XATTR_TRANS_BLOCKS;
	} else {
		/*
		 * Fast symlink. We have to add entry to directory
		 * (EXT4_DATA_TRANS_BLOCKS + EXT4_INDEX_EXTRA_TRANS_BLOCKS),
		 * allocate new inode (bitmap, group descriptor, inode block,
		 * quota blocks, sb is already counted in previous macros).
		 */
		credits = EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
			  EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3;
	}

	inode = ext4_new_inode_start_handle(dir, S_IFLNK|S_IRWXUGO,
					    &dentry->d_name, 0, NULL,
					    EXT4_HT_DIR, credits);
	handle = ext4_journal_current_handle();
	if (IS_ERR(inode)) {
		if (handle)
			ext4_journal_stop(handle);
		return PTR_ERR(inode);
	}

	if (IS_ENCRYPTED(inode)) {
		err = fscrypt_encrypt_symlink(inode, symname, len, &disk_link);
		if (err)
			goto err_drop_inode;
		inode->i_op = &ext4_encrypted_symlink_inode_operations;
	}

	if ((disk_link.len > EXT4_N_BLOCKS * 4)) {
		if (!IS_ENCRYPTED(inode))
			inode->i_op = &ext4_symlink_inode_operations;
		inode_nohighmem(inode);
		ext4_set_aops(inode);
		/*
		 * We cannot call page_symlink() with transaction started
		 * because it calls into ext4_write_begin() which can wait
		 * for transaction commit if we are running out of space
		 * and thus we deadlock. So we have to stop transaction now
		 * and restart it when symlink contents is written.
		 *
		 * To keep fs consistent in case of crash, we have to put inode
		 * to orphan list in the mean time.
		 */
		drop_nlink(inode);
		err = ext4_orphan_add(handle, inode);
		ext4_journal_stop(handle);
		handle = NULL;
		if (err)
			goto err_drop_inode;
		err = __page_symlink(inode, disk_link.name, disk_link.len, 1);
		if (err)
			goto err_drop_inode;
		/*
		 * Now inode is being linked into dir (EXT4_DATA_TRANS_BLOCKS
		 * + EXT4_INDEX_EXTRA_TRANS_BLOCKS), inode is also modified
		 */
		handle = ext4_journal_start(dir, EXT4_HT_DIR,
				EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
				EXT4_INDEX_EXTRA_TRANS_BLOCKS + 1);
		if (IS_ERR(handle)) {
			err = PTR_ERR(handle);
			handle = NULL;
			goto err_drop_inode;
		}
		set_nlink(inode, 1);
		err = ext4_orphan_del(handle, inode);
		if (err)
			goto err_drop_inode;
	} else {
		/* clear the extent format for fast symlink */
		ext4_clear_inode_flag(inode, EXT4_INODE_EXTENTS);
		if (!IS_ENCRYPTED(inode)) {
			inode->i_op = &ext4_fast_symlink_inode_operations;
			inode->i_link = (char *)&EXT4_I(inode)->i_data;
		}
		memcpy((char *)&EXT4_I(inode)->i_data, disk_link.name,
		       disk_link.len);
		inode->i_size = disk_link.len - 1;
	}
	EXT4_I(inode)->i_disksize = inode->i_size;
	err = ext4_add_nondir(handle, dentry, &inode);
	if (handle)
		ext4_journal_stop(handle);
	if (inode)
		iput(inode);
	goto out_free_encrypted_link;

err_drop_inode:
	if (handle)
		ext4_journal_stop(handle);
	clear_nlink(inode);
	unlock_new_inode(inode);
	iput(inode);
out_free_encrypted_link:
	if (disk_link.name != (unsigned char *)symname)
		kfree(disk_link.name);
	return err;
}


static inline unsigned dx_get_count(struct dx_entry *entries)
{
	return le16_to_cpu(((struct dx_countlimit *) entries)->count);
}


static int ext4_create(struct inode *dir, struct dentry *dentry, umode_t mode,
		       bool excl)
{
	handle_t *handle;
	struct inode *inode;
	int err, credits, retries = 0;

	err = dquot_initialize(dir);
	if (err)
		return err;

	credits = (EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
		   EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3);
retry:
	inode = ext4_new_inode_start_handle(dir, mode, &dentry->d_name, 0,
					    NULL, EXT4_HT_DIR, credits);
	handle = ext4_journal_current_handle();
	err = PTR_ERR(inode);
	if (!IS_ERR(inode)) {
		inode->i_op = &ext4_file_inode_operations;
		inode->i_fop = &ext4_file_operations;
		ext4_set_aops(inode);
		err = ext4_add_nondir(handle, dentry, &inode);
	}
	if (handle)
		ext4_journal_stop(handle);
	if (!IS_ERR_OR_NULL(inode))
		iput(inode);
	if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
		goto retry;
	return err;
}


static int ext4_rename_dir_finish(handle_t *handle, struct ext4_renament *ent,
				  unsigned dir_ino)
{
	int retval;

	ent->parent_de->inode = cpu_to_le32(dir_ino);
	BUFFER_TRACE(ent->dir_bh, "call ext4_handle_dirty_metadata");
	if (!ent->dir_inlined) {
		if (is_dx(ent->inode)) {
			retval = ext4_handle_dirty_dx_node(handle,
							   ent->inode,
							   ent->dir_bh);
		} else {
			retval = ext4_handle_dirty_dirblock(handle, ent->inode,
							    ent->dir_bh);
		}
	} else {
		retval = ext4_mark_inode_dirty(handle, ent->inode);
	}
	if (retval) {
		ext4_std_error(ent->dir->i_sb, retval);
		return retval;
	}
	return 0;
}


int ext4_handle_dirty_dirblock(handle_t *handle,
			       struct inode *inode,
			       struct buffer_head *bh)
{
	ext4_dirblock_csum_set(inode, bh);
	return ext4_handle_dirty_metadata(handle, inode, bh);
}


static inline void dx_set_count(struct dx_entry *entries, unsigned value)
{
	((struct dx_countlimit *) entries)->count = cpu_to_le16(value);
}


static void cmd_authinfo_sasl(char *cmd, char *mech, char *resp)
{
    int r, sasl_result;
    char *success_data;
    sasl_ssf_t ssf;
    char *ssfmsg = NULL;
    const void *val;
    int failedloginpause;
    struct proc_limits limits;

    /* Conceal initial response in telemetry log */
    if (nntp_logfd != -1 && resp) {
	(void)ftruncate(nntp_logfd,
		  lseek(nntp_logfd, -2, SEEK_CUR) - strlen(resp));
	(void)write(nntp_logfd, "...\r\n", 5);
    }

    if (nntp_userid) {
	prot_printf(nntp_out, "502 Already authenticated\r\n");
	return;
    }

    /* Stop telemetry logging during SASL exchange */
    if (nntp_logfd != -1 && mech) {
	prot_setlog(nntp_in, PROT_NO_FD);
	prot_setlog(nntp_out, PROT_NO_FD);
    }

    if (cmd[0] == 'g') {
	/* AUTHINFO GENERIC */
	if (!mech) {
	    /* If client didn't specify any mech we give them the list */
	    const char *sasllist;
	    int mechnum;

	    prot_printf(nntp_out, "281 List of mechanisms follows\r\n");

	    /* CRLF separated, dot terminated */
	    if (sasl_listmech(nntp_saslconn, NULL,
			      "", "\r\n", "\r\n",
			      &sasllist,
			      NULL, &mechnum) == SASL_OK) {
		if (mechnum > 0) {
		    prot_printf(nntp_out, "%s", sasllist);
		}
	    }

	    prot_printf(nntp_out, ".\r\n");
	    return;
	}

	r = saslserver(nntp_saslconn, mech, resp, "AUTHINFO GENERIC ", "381 ",
		       "", nntp_in, nntp_out, &sasl_result, &success_data);
    }
    else {
	/* AUTHINFO SASL */
	r = saslserver(nntp_saslconn, mech, resp, "", "383 ", "=",
		       nntp_in, nntp_out, &sasl_result, &success_data);
    }

    /* Restart any telemetry logging */
    prot_setlog(nntp_in, nntp_logfd);
    prot_setlog(nntp_out, nntp_logfd);

    if (r) {
	int code;
	const char *errorstring = NULL;

	switch (r) {
	case IMAP_SASL_CANCEL:
	    prot_printf(nntp_out,
			"481 Client canceled authentication\r\n");
	    break;
	case IMAP_SASL_PROTERR:
	    errorstring = prot_error(nntp_in);

	    prot_printf(nntp_out,
			"482 Error reading client response: %s\r\n",
			errorstring ? errorstring : "");
	    break;
	default:
	    /* failed authentication */
	    switch (sasl_result) {
	    case SASL_NOMECH:
	    case SASL_TOOWEAK:
		code = 503;
		break;
	    case SASL_ENCRYPT:
		code = 483;
		break;
	    case SASL_BADPROT:
		code = 482;
		break;
	    default:
		code = 481;
	    }

	    syslog(LOG_NOTICE, "badlogin: %s %s [%s]",
		   nntp_clienthost, mech, sasl_errdetail(nntp_saslconn));

	    failedloginpause = config_getint(IMAPOPT_FAILEDLOGINPAUSE);
	    if (failedloginpause != 0) {
	        sleep(failedloginpause);
	    }

	    /* Don't allow user probing */
	    if (sasl_result == SASL_NOUSER) sasl_result = SASL_BADAUTH;

	    errorstring = sasl_errstring(sasl_result, NULL, NULL);
	    if (errorstring) {
		prot_printf(nntp_out, "%d %s\r\n", code, errorstring);
	    } else {
		prot_printf(nntp_out, "%d Error authenticating\r\n", code);
	    }
	}

	reset_saslconn(&nntp_saslconn);
	return;
    }

    /* successful authentication */

    /* get the userid from SASL --- already canonicalized from
     * mysasl_proxy_policy()
     */
    sasl_result = sasl_getprop(nntp_saslconn, SASL_USERNAME, &val);
    if (sasl_result != SASL_OK) {
	prot_printf(nntp_out, "481 weird SASL error %d SASL_USERNAME\r\n",
		    sasl_result);
	syslog(LOG_ERR, "weird SASL error %d getting SASL_USERNAME",
	       sasl_result);
	reset_saslconn(&nntp_saslconn);
	return;
    }
    nntp_userid = xstrdup((const char *) val);

    sasl_getprop(nntp_saslconn, SASL_SSF, &val);
    ssf = *((sasl_ssf_t *) val);

    /* really, we should be doing a sasl_getprop on SASL_SSF_EXTERNAL,
       but the current libsasl doesn't allow that. */
    if (nntp_starttls_done) {
	switch(ssf) {
	case 0: ssfmsg = "tls protection"; break;
	case 1: ssfmsg = "tls plus integrity protection"; break;
	default: ssfmsg = "tls plus privacy protection"; break;
	}
    } else {
	switch(ssf) {
	case 0: ssfmsg = "no protection"; break;
	case 1: ssfmsg = "integrity protection"; break;
	default: ssfmsg = "privacy protection"; break;
	}
    }

    limits.procname = "nntpd";
    limits.clienthost = nntp_clienthost;
    limits.userid = nntp_userid;
    if (proc_checklimits(&limits)) {
	const char *sep = "";
	prot_printf(nntp_out,
		    "452 Too many open connections (");
	if (limits.maxhost) {
	    prot_printf(nntp_out, "%s%d of %d from %s", sep,
			limits.host, limits.maxhost, nntp_clienthost);
	    sep = ", ";
	}
	if (limits.maxuser) {
	    prot_printf(nntp_out, "%s%d of %d for %s", sep,
			limits.user, limits.maxuser, nntp_userid);
	}
	prot_printf(nntp_out, ")\r\n");
	reset_saslconn(&nntp_saslconn);
	free(nntp_userid);
	nntp_userid = NULL;
	return;
    }

    syslog(LOG_NOTICE, "login: %s %s %s%s %s", nntp_clienthost, nntp_userid,
	   mech, nntp_starttls_done ? "+TLS" : "", "User logged in");

    proc_register("nntpd", nntp_clienthost, nntp_userid, NULL);

    if (success_data) {
	prot_printf(nntp_out, "283 %s\r\n", success_data);
	free(success_data);
    } else {
	prot_printf(nntp_out, "281 Success (%s)\r\n", ssfmsg);
    }

    prot_setsasl(nntp_in,  nntp_saslconn);
    prot_setsasl(nntp_out, nntp_saslconn);

    /* Close IP-based telemetry log and create new log based on userid */
    if (nntp_logfd != -1) close(nntp_logfd);
    nntp_logfd = telemetry_log(nntp_userid, nntp_in, nntp_out, 0);

    if (ssf) {
	/* close any selected group */
	if (group_state)
	    index_close(&group_state);
	if (backend_current) {
	    proxy_downserver(backend_current);
	    backend_current = NULL;
	}
    }
}

CVE-2011-3208 - fix buffer overflow in nntpd


static void parse_groups(const char *groups, message_data_t *msg)
{
    const char *p;
    char *rcpt = NULL;
    char *buf = xstrdup(groups);
    const char sep[] = ", \t";

    for (p = strtok(buf, sep) ; p ; p = strtok(NULL, sep)) {
	/* construct the mailbox name */
	free(rcpt);
	rcpt = strconcat(newsprefix, p, (char *)NULL);

	/* skip mailboxes that we don't serve as newsgroups */
	if (!is_newsgroup(rcpt)) continue;

	/* Only add mailboxes that exist */
	if (!mlookup(rcpt, NULL)) {
	    strarray_appendm(&msg->rcpt, rcpt);
	    rcpt = NULL;
	}
    }
    free(rcpt);
    free(buf);
}


int msg_new(message_data_t **m)
{
    message_data_t *ret = (message_data_t *) xmalloc(sizeof(message_data_t));

    ret->data = NULL;
    ret->f = NULL;
    ret->id = NULL;
    ret->path = NULL;
    ret->control = NULL;
    ret->size = 0;
    strarray_init(&ret->rcpt);
    ret->date = NULL;

    ret->hdrcache = spool_new_hdrcache();

    *m = ret;
    return 0;
}