#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 mnt_idmap *idmap, 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(&nop_mnt_idmap, inode, dir, mode);
inode->i_mtime = inode->i_atime = inode_set_ctime_current(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:%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_mtime = 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;
old_dir->i_mtime = 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);
}
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;
inode_set_ctime_current(dir);
}
dir->i_mtime = 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;
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;
}