360 lines
8.5 KiB
C
360 lines
8.5 KiB
C
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// SPDX-License-Identifier: GPL-2.0
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/*
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* fs/bfs/dir.c
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* BFS directory operations.
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* Copyright (C) 1999,2000 Tigran Aivazian <tigran@veritas.com>
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* Made endianness-clean by Andrew Stribblehill <ads@wompom.org> 2005
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*/
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#include <linux/time.h>
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#include <linux/string.h>
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#include <linux/fs.h>
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#include <linux/buffer_head.h>
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#include <linux/sched.h>
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#include "bfs.h"
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#undef DEBUG
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#ifdef DEBUG
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#define dprintf(x...) printf(x)
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#else
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#define dprintf(x...)
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#endif
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static int bfs_add_entry(struct inode *dir, const struct qstr *child, int ino);
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static struct buffer_head *bfs_find_entry(struct inode *dir,
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const struct qstr *child,
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struct bfs_dirent **res_dir);
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static int bfs_readdir(struct file *f, struct dir_context *ctx)
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{
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struct inode *dir = file_inode(f);
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struct buffer_head *bh;
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struct bfs_dirent *de;
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unsigned int offset;
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int block;
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if (ctx->pos & (BFS_DIRENT_SIZE - 1)) {
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printf("Bad f_pos=%08lx for %s:%08lx\n",
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(unsigned long)ctx->pos,
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dir->i_sb->s_id, dir->i_ino);
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return -EINVAL;
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}
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while (ctx->pos < dir->i_size) {
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offset = ctx->pos & (BFS_BSIZE - 1);
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block = BFS_I(dir)->i_sblock + (ctx->pos >> BFS_BSIZE_BITS);
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bh = sb_bread(dir->i_sb, block);
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if (!bh) {
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ctx->pos += BFS_BSIZE - offset;
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continue;
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}
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do {
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de = (struct bfs_dirent *)(bh->b_data + offset);
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if (de->ino) {
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int size = strnlen(de->name, BFS_NAMELEN);
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if (!dir_emit(ctx, de->name, size,
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le16_to_cpu(de->ino),
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DT_UNKNOWN)) {
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brelse(bh);
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return 0;
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}
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}
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offset += BFS_DIRENT_SIZE;
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ctx->pos += BFS_DIRENT_SIZE;
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} while ((offset < BFS_BSIZE) && (ctx->pos < dir->i_size));
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brelse(bh);
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}
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return 0;
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}
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const struct file_operations bfs_dir_operations = {
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.read = generic_read_dir,
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.iterate_shared = bfs_readdir,
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.fsync = generic_file_fsync,
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.llseek = generic_file_llseek,
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};
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static int bfs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
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bool excl)
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{
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int err;
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struct inode *inode;
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struct super_block *s = dir->i_sb;
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struct bfs_sb_info *info = BFS_SB(s);
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unsigned long ino;
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inode = new_inode(s);
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if (!inode)
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return -ENOMEM;
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mutex_lock(&info->bfs_lock);
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ino = find_first_zero_bit(info->si_imap, info->si_lasti + 1);
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if (ino > info->si_lasti) {
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mutex_unlock(&info->bfs_lock);
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iput(inode);
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return -ENOSPC;
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}
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set_bit(ino, info->si_imap);
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info->si_freei--;
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inode_init_owner(inode, dir, mode);
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inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode);
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inode->i_blocks = 0;
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inode->i_op = &bfs_file_inops;
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inode->i_fop = &bfs_file_operations;
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inode->i_mapping->a_ops = &bfs_aops;
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inode->i_ino = ino;
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BFS_I(inode)->i_dsk_ino = ino;
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BFS_I(inode)->i_sblock = 0;
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BFS_I(inode)->i_eblock = 0;
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insert_inode_hash(inode);
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mark_inode_dirty(inode);
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bfs_dump_imap("create", s);
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err = bfs_add_entry(dir, &dentry->d_name, inode->i_ino);
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if (err) {
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inode_dec_link_count(inode);
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mutex_unlock(&info->bfs_lock);
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iput(inode);
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return err;
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}
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mutex_unlock(&info->bfs_lock);
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d_instantiate(dentry, inode);
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return 0;
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}
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static struct dentry *bfs_lookup(struct inode *dir, struct dentry *dentry,
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unsigned int flags)
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{
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struct inode *inode = NULL;
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struct buffer_head *bh;
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struct bfs_dirent *de;
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struct bfs_sb_info *info = BFS_SB(dir->i_sb);
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if (dentry->d_name.len > BFS_NAMELEN)
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return ERR_PTR(-ENAMETOOLONG);
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mutex_lock(&info->bfs_lock);
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bh = bfs_find_entry(dir, &dentry->d_name, &de);
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if (bh) {
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unsigned long ino = (unsigned long)le16_to_cpu(de->ino);
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brelse(bh);
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inode = bfs_iget(dir->i_sb, ino);
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}
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mutex_unlock(&info->bfs_lock);
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return d_splice_alias(inode, dentry);
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}
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static int bfs_link(struct dentry *old, struct inode *dir,
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struct dentry *new)
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{
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struct inode *inode = d_inode(old);
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struct bfs_sb_info *info = BFS_SB(inode->i_sb);
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int err;
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mutex_lock(&info->bfs_lock);
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err = bfs_add_entry(dir, &new->d_name, inode->i_ino);
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if (err) {
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mutex_unlock(&info->bfs_lock);
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return err;
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}
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inc_nlink(inode);
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inode->i_ctime = current_time(inode);
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mark_inode_dirty(inode);
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ihold(inode);
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d_instantiate(new, inode);
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mutex_unlock(&info->bfs_lock);
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return 0;
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}
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static int bfs_unlink(struct inode *dir, struct dentry *dentry)
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{
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int error = -ENOENT;
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struct inode *inode = d_inode(dentry);
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struct buffer_head *bh;
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struct bfs_dirent *de;
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struct bfs_sb_info *info = BFS_SB(inode->i_sb);
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mutex_lock(&info->bfs_lock);
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bh = bfs_find_entry(dir, &dentry->d_name, &de);
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if (!bh || (le16_to_cpu(de->ino) != inode->i_ino))
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goto out_brelse;
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if (!inode->i_nlink) {
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printf("unlinking non-existent file %s:%lu (nlink=%d)\n",
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inode->i_sb->s_id, inode->i_ino,
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inode->i_nlink);
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set_nlink(inode, 1);
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}
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de->ino = 0;
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mark_buffer_dirty_inode(bh, dir);
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dir->i_ctime = dir->i_mtime = current_time(dir);
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mark_inode_dirty(dir);
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inode->i_ctime = dir->i_ctime;
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inode_dec_link_count(inode);
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error = 0;
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out_brelse:
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brelse(bh);
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mutex_unlock(&info->bfs_lock);
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return error;
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}
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static int bfs_rename(struct inode *old_dir, struct dentry *old_dentry,
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struct inode *new_dir, struct dentry *new_dentry,
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unsigned int flags)
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{
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struct inode *old_inode, *new_inode;
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struct buffer_head *old_bh, *new_bh;
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struct bfs_dirent *old_de, *new_de;
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struct bfs_sb_info *info;
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int error = -ENOENT;
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if (flags & ~RENAME_NOREPLACE)
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return -EINVAL;
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old_bh = new_bh = NULL;
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old_inode = d_inode(old_dentry);
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if (S_ISDIR(old_inode->i_mode))
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return -EINVAL;
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info = BFS_SB(old_inode->i_sb);
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mutex_lock(&info->bfs_lock);
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old_bh = bfs_find_entry(old_dir, &old_dentry->d_name, &old_de);
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if (!old_bh || (le16_to_cpu(old_de->ino) != old_inode->i_ino))
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goto end_rename;
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error = -EPERM;
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new_inode = d_inode(new_dentry);
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new_bh = bfs_find_entry(new_dir, &new_dentry->d_name, &new_de);
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if (new_bh && !new_inode) {
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brelse(new_bh);
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new_bh = NULL;
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}
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if (!new_bh) {
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error = bfs_add_entry(new_dir, &new_dentry->d_name,
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old_inode->i_ino);
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if (error)
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goto end_rename;
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}
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old_de->ino = 0;
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old_dir->i_ctime = old_dir->i_mtime = current_time(old_dir);
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mark_inode_dirty(old_dir);
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if (new_inode) {
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new_inode->i_ctime = current_time(new_inode);
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inode_dec_link_count(new_inode);
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}
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mark_buffer_dirty_inode(old_bh, old_dir);
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error = 0;
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end_rename:
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mutex_unlock(&info->bfs_lock);
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brelse(old_bh);
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brelse(new_bh);
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return error;
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}
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const struct inode_operations bfs_dir_inops = {
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.create = bfs_create,
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.lookup = bfs_lookup,
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.link = bfs_link,
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.unlink = bfs_unlink,
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.rename = bfs_rename,
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};
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static int bfs_add_entry(struct inode *dir, const struct qstr *child, int ino)
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{
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const unsigned char *name = child->name;
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int namelen = child->len;
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struct buffer_head *bh;
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struct bfs_dirent *de;
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int block, sblock, eblock, off, pos;
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int i;
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dprintf("name=%s, namelen=%d\n", name, namelen);
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if (!namelen)
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return -ENOENT;
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if (namelen > BFS_NAMELEN)
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return -ENAMETOOLONG;
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sblock = BFS_I(dir)->i_sblock;
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eblock = BFS_I(dir)->i_eblock;
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for (block = sblock; block <= eblock; block++) {
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bh = sb_bread(dir->i_sb, block);
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if (!bh)
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return -EIO;
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for (off = 0; off < BFS_BSIZE; off += BFS_DIRENT_SIZE) {
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de = (struct bfs_dirent *)(bh->b_data + off);
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if (!de->ino) {
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pos = (block - sblock) * BFS_BSIZE + off;
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if (pos >= dir->i_size) {
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dir->i_size += BFS_DIRENT_SIZE;
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dir->i_ctime = current_time(dir);
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}
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dir->i_mtime = current_time(dir);
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mark_inode_dirty(dir);
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de->ino = cpu_to_le16((u16)ino);
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for (i = 0; i < BFS_NAMELEN; i++)
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de->name[i] =
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(i < namelen) ? name[i] : 0;
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mark_buffer_dirty_inode(bh, dir);
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brelse(bh);
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return 0;
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}
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}
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brelse(bh);
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}
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return -ENOSPC;
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}
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static inline int bfs_namecmp(int len, const unsigned char *name,
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const char *buffer)
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{
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if ((len < BFS_NAMELEN) && buffer[len])
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return 0;
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return !memcmp(name, buffer, len);
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}
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static struct buffer_head *bfs_find_entry(struct inode *dir,
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const struct qstr *child,
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struct bfs_dirent **res_dir)
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{
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unsigned long block = 0, offset = 0;
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struct buffer_head *bh = NULL;
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struct bfs_dirent *de;
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const unsigned char *name = child->name;
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int namelen = child->len;
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*res_dir = NULL;
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if (namelen > BFS_NAMELEN)
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return NULL;
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while (block * BFS_BSIZE + offset < dir->i_size) {
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if (!bh) {
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bh = sb_bread(dir->i_sb, BFS_I(dir)->i_sblock + block);
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if (!bh) {
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block++;
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continue;
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}
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}
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de = (struct bfs_dirent *)(bh->b_data + offset);
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offset += BFS_DIRENT_SIZE;
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if (le16_to_cpu(de->ino) &&
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bfs_namecmp(namelen, name, de->name)) {
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*res_dir = de;
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return bh;
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}
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if (offset < bh->b_size)
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continue;
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brelse(bh);
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bh = NULL;
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offset = 0;
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block++;
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}
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brelse(bh);
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return NULL;
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}
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