// SPDX-License-Identifier: GPL-2.0/* *	fs/bfs/dir.c *	BFS directory operations. *	Copyright (C) 1999-2018  Tigran Aivazian <aivazian.tigran@gmail.com> *  Made endianness-clean by Andrew Stribblehill <ads@wompom.org> 2005 */ #include <linux/time.h>#include <linux/string.h>#include <linux/fs.h>#include <linux/buffer_head.h>#include <linux/sched.h>#include "bfs.h" #undef DEBUG #ifdef DEBUG#define dprintf(x...)	printf(x)#else#define dprintf(x...)#endif static int bfs_add_entry(struct inode *dir, const struct qstr *child, int ino);static struct buffer_head *bfs_find_entry(struct inode *dir,				const struct qstr *child,				struct bfs_dirent **res_dir); static int bfs_readdir(struct file *f, struct dir_context *ctx){	struct inode *dir = file_inode(f);	struct buffer_head *bh;	struct bfs_dirent *de;	unsigned int offset;	int block; 	if (ctx->pos & (BFS_DIRENT_SIZE - 1)) {		printf("Bad f_pos=%08lx for %s:%08llx\n",					(unsigned long)ctx->pos,					dir->i_sb->s_id, dir->i_ino);		return -EINVAL;	} 	while (ctx->pos < dir->i_size) {		offset = ctx->pos & (BFS_BSIZE - 1);		block = BFS_I(dir)->i_sblock + (ctx->pos >> BFS_BSIZE_BITS);		bh = sb_bread(dir->i_sb, block);		if (!bh) {			ctx->pos += BFS_BSIZE - offset;			continue;		}		do {			de = (struct bfs_dirent *)(bh->b_data + offset);			if (de->ino) {				int size = strnlen(de->name, BFS_NAMELEN);				if (!dir_emit(ctx, de->name, size,						le16_to_cpu(de->ino),						DT_UNKNOWN)) {					brelse(bh);					return 0;				}			}			offset += BFS_DIRENT_SIZE;			ctx->pos += BFS_DIRENT_SIZE;		} while ((offset < BFS_BSIZE) && (ctx->pos < dir->i_size));		brelse(bh);	}	return 0;} const struct file_operations bfs_dir_operations = {	.read		= generic_read_dir,	.iterate_shared	= bfs_readdir,	.fsync		= simple_fsync,	.llseek		= generic_file_llseek,}; static int bfs_create(struct mnt_idmap *idmap, struct inode *dir,		      struct dentry *dentry, umode_t mode){	int err;	struct inode *inode;	struct super_block *s = dir->i_sb;	struct bfs_sb_info *info = BFS_SB(s);	unsigned long ino; 	inode = new_inode(s);	if (!inode)		return -ENOMEM;	mutex_lock(&info->bfs_lock);	ino = find_first_zero_bit(info->si_imap, info->si_lasti + 1);	if (ino > info->si_lasti) {		mutex_unlock(&info->bfs_lock);		iput(inode);		return -ENOSPC;	}	set_bit(ino, info->si_imap);	info->si_freei--;	inode_init_owner(&nop_mnt_idmap, inode, dir, mode);	simple_inode_init_ts(inode);	inode->i_blocks = 0;	inode->i_op = &bfs_file_inops;	inode->i_fop = &bfs_file_operations;	inode->i_mapping->a_ops = &bfs_aops;	inode->i_ino = ino;	BFS_I(inode)->i_dsk_ino = ino;	BFS_I(inode)->i_sblock = 0;	BFS_I(inode)->i_eblock = 0;	insert_inode_hash(inode);        mark_inode_dirty(inode);	bfs_dump_imap("create", s); 	err = bfs_add_entry(dir, &dentry->d_name, inode->i_ino);	if (err) {		inode_dec_link_count(inode);		mutex_unlock(&info->bfs_lock);		iput(inode);		return err;	}	mutex_unlock(&info->bfs_lock);	d_instantiate(dentry, inode);	return 0;} static struct dentry *bfs_lookup(struct inode *dir, struct dentry *dentry,						unsigned int flags){	struct inode *inode = NULL;	struct buffer_head *bh;	struct bfs_dirent *de;	struct bfs_sb_info *info = BFS_SB(dir->i_sb); 	if (dentry->d_name.len > BFS_NAMELEN)		return ERR_PTR(-ENAMETOOLONG); 	mutex_lock(&info->bfs_lock);	bh = bfs_find_entry(dir, &dentry->d_name, &de);	if (bh) {		unsigned long ino = (unsigned long)le16_to_cpu(de->ino);		brelse(bh);		inode = bfs_iget(dir->i_sb, ino);	}	mutex_unlock(&info->bfs_lock);	return d_splice_alias(inode, dentry);} static int bfs_link(struct dentry *old, struct inode *dir,						struct dentry *new){	struct inode *inode = d_inode(old);	struct bfs_sb_info *info = BFS_SB(inode->i_sb);	int err; 	mutex_lock(&info->bfs_lock);	err = bfs_add_entry(dir, &new->d_name, inode->i_ino);	if (err) {		mutex_unlock(&info->bfs_lock);		return err;	}	inc_nlink(inode);	inode_set_ctime_current(inode);	mark_inode_dirty(inode);	ihold(inode);	d_instantiate(new, inode);	mutex_unlock(&info->bfs_lock);	return 0;} static int bfs_unlink(struct inode *dir, struct dentry *dentry){	int error = -ENOENT;	struct inode *inode = d_inode(dentry);	struct buffer_head *bh;	struct bfs_dirent *de;	struct bfs_sb_info *info = BFS_SB(inode->i_sb); 	mutex_lock(&info->bfs_lock);	bh = bfs_find_entry(dir, &dentry->d_name, &de);	if (!bh || (le16_to_cpu(de->ino) != inode->i_ino))		goto out_brelse; 	if (!inode->i_nlink) {		printf("unlinking non-existent file %s:%llu (nlink=%d)\n",					inode->i_sb->s_id, inode->i_ino,					inode->i_nlink);		set_nlink(inode, 1);	}	de->ino = 0;	mmb_mark_buffer_dirty(bh, &BFS_I(dir)->i_metadata_bhs);	inode_set_mtime_to_ts(dir, inode_set_ctime_current(dir));	mark_inode_dirty(dir);	inode_set_ctime_to_ts(inode, inode_get_ctime(dir));	inode_dec_link_count(inode);	error = 0; out_brelse:	brelse(bh);	mutex_unlock(&info->bfs_lock);	return error;} static int bfs_rename(struct mnt_idmap *idmap, struct inode *old_dir,		      struct dentry *old_dentry, struct inode *new_dir,		      struct dentry *new_dentry, unsigned int flags){	struct inode *old_inode, *new_inode;	struct buffer_head *old_bh, *new_bh;	struct bfs_dirent *old_de, *new_de;	struct bfs_sb_info *info;	int error = -ENOENT; 	if (flags & ~RENAME_NOREPLACE)		return -EINVAL; 	old_bh = new_bh = NULL;	old_inode = d_inode(old_dentry);	if (S_ISDIR(old_inode->i_mode))		return -EINVAL; 	info = BFS_SB(old_inode->i_sb); 	mutex_lock(&info->bfs_lock);	old_bh = bfs_find_entry(old_dir, &old_dentry->d_name, &old_de); 	if (!old_bh || (le16_to_cpu(old_de->ino) != old_inode->i_ino))		goto end_rename; 	error = -EPERM;	new_inode = d_inode(new_dentry);	new_bh = bfs_find_entry(new_dir, &new_dentry->d_name, &new_de); 	if (new_bh && !new_inode) {		brelse(new_bh);		new_bh = NULL;	}	if (!new_bh) {		error = bfs_add_entry(new_dir, &new_dentry->d_name,					old_inode->i_ino);		if (error)			goto end_rename;	}	old_de->ino = 0;	inode_set_mtime_to_ts(old_dir, inode_set_ctime_current(old_dir));	mark_inode_dirty(old_dir);	if (new_inode) {		inode_set_ctime_current(new_inode);		inode_dec_link_count(new_inode);	}	mmb_mark_buffer_dirty(old_bh, &BFS_I(old_dir)->i_metadata_bhs);	error = 0; end_rename:	mutex_unlock(&info->bfs_lock);	brelse(old_bh);	brelse(new_bh);	return error;} const struct inode_operations bfs_dir_inops = {	.create			= bfs_create,	.lookup			= bfs_lookup,	.link			= bfs_link,	.unlink			= bfs_unlink,	.rename			= bfs_rename,}; static int bfs_add_entry(struct inode *dir, const struct qstr *child, int ino){	const unsigned char *name = child->name;	int namelen = child->len;	struct buffer_head *bh;	struct bfs_dirent *de;	int block, sblock, eblock, off, pos;	int i; 	dprintf("name=%s, namelen=%d\n", name, namelen); 	sblock = BFS_I(dir)->i_sblock;	eblock = BFS_I(dir)->i_eblock;	for (block = sblock; block <= eblock; block++) {		bh = sb_bread(dir->i_sb, block);		if (!bh)			return -EIO;		for (off = 0; off < BFS_BSIZE; off += BFS_DIRENT_SIZE) {			de = (struct bfs_dirent *)(bh->b_data + off);			if (!de->ino) {				pos = (block - sblock) * BFS_BSIZE + off;				if (pos >= dir->i_size) {					dir->i_size += BFS_DIRENT_SIZE;					inode_set_ctime_current(dir);				}				inode_set_mtime_to_ts(dir,						      inode_set_ctime_current(dir));				mark_inode_dirty(dir);				de->ino = cpu_to_le16((u16)ino);				for (i = 0; i < BFS_NAMELEN; i++)					de->name[i] =						(i < namelen) ? name[i] : 0;				mmb_mark_buffer_dirty(bh,						&BFS_I(dir)->i_metadata_bhs);				brelse(bh);				return 0;			}		}		brelse(bh);	}	return -ENOSPC;} static inline int bfs_namecmp(int len, const unsigned char *name,							const char *buffer){	if ((len < BFS_NAMELEN) && buffer[len])		return 0;	return !memcmp(name, buffer, len);} static struct buffer_head *bfs_find_entry(struct inode *dir,			const struct qstr *child,			struct bfs_dirent **res_dir){	unsigned long block = 0, offset = 0;	struct buffer_head *bh = NULL;	struct bfs_dirent *de;	const unsigned char *name = child->name;	int namelen = child->len; 	*res_dir = NULL;	if (namelen > BFS_NAMELEN)		return NULL; 	while (block * BFS_BSIZE + offset < dir->i_size) {		if (!bh) {			bh = sb_bread(dir->i_sb, BFS_I(dir)->i_sblock + block);			if (!bh) {				block++;				continue;			}		}		de = (struct bfs_dirent *)(bh->b_data + offset);		offset += BFS_DIRENT_SIZE;		if (le16_to_cpu(de->ino) &&				bfs_namecmp(namelen, name, de->name)) {			*res_dir = de;			return bh;		}		if (offset < bh->b_size)			continue;		brelse(bh);		bh = NULL;		offset = 0;		block++;	}	brelse(bh);	return NULL;}