1 files changed, 359 insertions, 0 deletions

diff --git a/fs/bfs/dir.c b/fs/bfs/dir.c
new file mode 100644
index 000000000..34d4f68f7
--- /dev/null
+++ b/fs/bfs/dir.c
@@ -0,0 +1,359 @@
+// 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:%08lx\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		= generic_file_fsync,
+	.llseek		= generic_file_llseek,
+};
+
+static int bfs_create(struct user_namespace *mnt_userns, struct inode *dir,
+		      struct dentry *dentry, umode_t mode, bool excl)
+{
+	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(&init_user_ns, inode, dir, mode);
+	inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(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->i_ctime = current_time(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:%lu (nlink=%d)\n",
+					inode->i_sb->s_id, inode->i_ino,
+					inode->i_nlink);
+		set_nlink(inode, 1);
+	}
+	de->ino = 0;
+	mark_buffer_dirty_inode(bh, dir);
+	dir->i_ctime = dir->i_mtime = current_time(dir);
+	mark_inode_dirty(dir);
+	inode->i_ctime = dir->i_ctime;
+	inode_dec_link_count(inode);
+	error = 0;
+
+out_brelse:
+	brelse(bh);
+	mutex_unlock(&info->bfs_lock);
+	return error;
+}
+
+static int bfs_rename(struct user_namespace *mnt_userns, 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;
+	old_dir->i_ctime = old_dir->i_mtime = current_time(old_dir);
+	mark_inode_dirty(old_dir);
+	if (new_inode) {
+		new_inode->i_ctime = current_time(new_inode);
+		inode_dec_link_count(new_inode);
+	}
+	mark_buffer_dirty_inode(old_bh, old_dir);
+	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);
+
+	if (!namelen)
+		return -ENOENT;
+	if (namelen > BFS_NAMELEN)
+		return -ENAMETOOLONG;
+
+	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;
+					dir->i_ctime = current_time(dir);
+				}
+				dir->i_mtime = current_time(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;
+				mark_buffer_dirty_inode(bh, dir);
+				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;
+}