/*
* linux/fs/minix/namei.c
*
* Copyright (C) 1991, 1992 Linus Torvalds
*/
#include <linux/sched.h>
#include <linux/minix_fs.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/stat.h>
#include <linux/fcntl.h>
#include <linux/errno.h>
#include <linux/quotaops.h>
#include <asm/uaccess.h>
/*
* comment out this line if you want names > info->s_namelen chars to be
* truncated. Else they will be disallowed (ENAMETOOLONG).
*/
/* #define NO_TRUNCATE */
static inline int namecompare(int len, int maxlen,
const char * name, const char * buffer)
{
if (len < maxlen && buffer[len])
return 0;
return !memcmp(name, buffer, len);
}
/*
* minix_find_entry()
*
* finds an entry in the specified directory with the wanted name. It
* returns the cache buffer in which the entry was found, and the entry
* itself (as a parameter - res_dir). It does NOT read the inode of the
* entry - you'll have to do that yourself if you want to.
*/
static struct buffer_head * minix_find_entry(struct inode * dir,
const char * name, int namelen, struct minix_dir_entry ** res_dir)
{
unsigned long block, offset;
struct buffer_head * bh;
struct minix_sb_info * info;
struct minix_dir_entry *de;
*res_dir = NULL;
info = &dir->i_sb->u.minix_sb;
if (namelen > info->s_namelen) {
#ifdef NO_TRUNCATE
return NULL;
#else
namelen = info->s_namelen;
#endif
}
bh = NULL;
block = offset = 0;
while (block*BLOCK_SIZE+offset < dir->i_size) {
if (!bh) {
bh = minix_bread(dir,block,0);
if (!bh) {
block++;
continue;
}
}
de = (struct minix_dir_entry *) (bh->b_data + offset);
offset += info->s_dirsize;
if (de->inode && namecompare(namelen,info->s_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;
}
#ifndef NO_TRUNCATE
static int minix_hash(struct dentry *dentry, struct qstr *qstr)
{
unsigned long hash;
int i;
const unsigned char *name;
i = dentry->d_inode->i_sb->u.minix_sb.s_namelen;
if (i >= qstr->len)
return 0;
/* Truncate the name in place, avoids having to define a compare
function. */
qstr->len = i;
name = qstr->name;
hash = init_name_hash();
while (i--)
hash = partial_name_hash(*name++, hash);
qstr->hash = end_name_hash(hash);
return 0;
}
#endif
struct dentry_operations minix_dentry_operations = {
#ifndef NO_TRUNCATE
d_hash: minix_hash,
#endif
};
static struct dentry *minix_lookup(struct inode * dir, struct dentry *dentry)
{
struct inode * inode = NULL;
struct minix_dir_entry * de;
struct buffer_head * bh;
#ifndef NO_TRUNCATE
dentry->d_op = &minix_dentry_operations;
#endif
bh = minix_find_entry(dir, dentry->d_name.name, dentry->d_name.len, &de);
if (bh) {
int ino = de->inode;
brelse (bh);
inode = iget(dir->i_sb, ino);
if (!inode)
return ERR_PTR(-EACCES);
}
d_add(dentry, inode);
return NULL;
}
/*
* minix_add_entry()
*
* adds a file entry to the specified directory, returning a possible
* error value if it fails.
*
* NOTE!! The inode part of 'de' is left at 0 - which means you
* may not sleep between calling this and putting something into
* the entry, as someone else might have used it while you slept.
*/
static int minix_add_entry(struct inode * dir,
const char * name, int namelen,
struct buffer_head ** res_buf,
struct minix_dir_entry ** res_dir)
{
int i;
unsigned long block, offset;
struct buffer_head * bh;
struct minix_dir_entry * de;
struct minix_sb_info * info;
*res_buf = NULL;
*res_dir = NULL;
info = &dir->i_sb->u.minix_sb;
if (namelen > info->s_namelen) {
#ifdef NO_TRUNCATE
return -ENAMETOOLONG;
#else
namelen = info->s_namelen;
#endif
}
if (!namelen)
return -ENOENT;
bh = NULL;
block = offset = 0;
while (1) {
if (!bh) {
bh = minix_bread(dir,block,1);
if (!bh)
return -ENOSPC;
}
de = (struct minix_dir_entry *) (bh->b_data + offset);
offset += info->s_dirsize;
if (block*bh->b_size + offset > dir->i_size) {
de->inode = 0;
dir->i_size = block*bh->b_size + offset;
mark_inode_dirty(dir);
}
if (!de->inode) {
dir->i_mtime = dir->i_ctime = CURRENT_TIME;
mark_inode_dirty(dir);
for (i = 0; i < info->s_namelen ; i++)
de->name[i] = (i < namelen) ? name[i] : 0;
dir->i_version = ++event;
mark_buffer_dirty(bh);
*res_dir = de;
break;
}
if (offset < bh->b_size)
continue;
brelse(bh);
bh = NULL;
offset = 0;
block++;
}
*res_buf = bh;
return 0;
}
static int minix_create(struct inode * dir, struct dentry *dentry, int mode)
{
int error;
struct inode * inode;
struct buffer_head * bh;
struct minix_dir_entry * de;
inode = minix_new_inode(dir, &error);
if (!inode)
return error;
inode->i_op = &minix_file_inode_operations;
inode->i_fop = &minix_file_operations;
inode->i_mapping->a_ops = &minix_aops;
inode->i_mode = mode;
mark_inode_dirty(inode);
error = minix_add_entry(dir, dentry->d_name.name,
dentry->d_name.len, &bh ,&de);
if (error) {
inode->i_nlink--;
mark_inode_dirty(inode);
iput(inode);
return error;
}
de->inode = inode->i_ino;
mark_buffer_dirty(bh);
brelse(bh);
d_instantiate(dentry, inode);
return 0;
}
static int minix_mknod(struct inode * dir, struct dentry *dentry, int mode, int rdev)
{
int error;
struct inode * inode;
struct buffer_head * bh;
struct minix_dir_entry * de;
inode = minix_new_inode(dir, &error);
if (!inode)
return error;
inode->i_uid = current->fsuid;
init_special_inode(inode, mode, rdev);
mark_inode_dirty(inode);
error = minix_add_entry(dir, dentry->d_name.name, dentry->d_name.len, &bh, &de);
if (error) {
inode->i_nlink--;
mark_inode_dirty(inode);
iput(inode);
return error;
}
de->inode = inode->i_ino;
mark_buffer_dirty(bh);
brelse(bh);
d_instantiate(dentry, inode);
return 0;
}
static int minix_mkdir(struct inode * dir, struct dentry *dentry, int mode)
{
int error;
struct inode * inode;
struct buffer_head * bh, *dir_block;
struct minix_dir_entry * de;
struct minix_sb_info * info;
info = &dir->i_sb->u.minix_sb;
if (dir->i_nlink >= info->s_link_max)
return -EMLINK;
inode = minix_new_inode(dir, &error);
if (!inode)
return error;
inode->i_op = &minix_dir_inode_operations;
inode->i_fop = &minix_dir_operations;
inode->i_size = 2 * info->s_dirsize;
dir_block = minix_bread(inode,0,1);
if (!dir_block) {
inode->i_nlink--;
mark_inode_dirty(inode);
iput(inode);
return -ENOSPC;
}
de = (struct minix_dir_entry *) dir_block->b_data;
de->inode=inode->i_ino;
strcpy(de->name,".");
de = (struct minix_dir_entry *) (dir_block->b_data + info->s_dirsize);
de->inode = dir->i_ino;
strcpy(de->name,"..");
inode->i_nlink = 2;
mark_buffer_dirty(dir_block);
brelse(dir_block);
inode->i_mode = S_IFDIR | mode;
if (dir->i_mode & S_ISGID)
inode->i_mode |= S_ISGID;
mark_inode_dirty(inode);
error = minix_add_entry(dir, dentry->d_name.name,
dentry->d_name.len, &bh, &de);
if (error) {
inode->i_nlink=0;
iput(inode);
return error;
}
de->inode = inode->i_ino;
mark_buffer_dirty(bh);
dir->i_nlink++;
mark_inode_dirty(dir);
brelse(bh);
d_instantiate(dentry, inode);
return 0;
}
/*
* routine to check that the specified directory is empty (for rmdir)
*/
static int empty_dir(struct inode * inode)
{
unsigned int block, offset;
struct buffer_head * bh;
struct minix_dir_entry * de;
struct minix_sb_info * info;
info = &inode->i_sb->u.minix_sb;
block = 0;
bh = NULL;
offset = 2*info->s_dirsize;
if (inode->i_size & (info->s_dirsize-1))
goto bad_dir;
if (inode->i_size < offset)
goto bad_dir;
bh = minix_bread(inode,0,0);
if (!bh)
goto bad_dir;
de = (struct minix_dir_entry *) bh->b_data;
if (!de->inode || strcmp(de->name,"."))
goto bad_dir;
de = (struct minix_dir_entry *) (bh->b_data + info->s_dirsize);
if (!de->inode || strcmp(de->name,".."))
goto bad_dir;
while (block*BLOCK_SIZE+offset < inode->i_size) {
if (!bh) {
bh = minix_bread(inode,block,0);
if (!bh) {
block++;
continue;
}
}
de = (struct minix_dir_entry *) (bh->b_data + offset);
offset += info->s_dirsize;
if (de->inode) {
brelse(bh);
return 0;
}
if (offset < bh->b_size)
continue;
brelse(bh);
bh = NULL;
offset = 0;
block++;
}
brelse(bh);
return 1;
bad_dir:
brelse(bh);
printk("Bad directory on device %s\n",
kdevname(inode->i_dev));
return 1;
}
static int minix_rmdir(struct inode * dir, struct dentry *dentry)
{
int retval;
struct inode * inode;
struct buffer_head * bh;
struct minix_dir_entry * de;
inode = NULL;
bh = minix_find_entry(dir, dentry->d_name.name,
dentry->d_name.len, &de);
retval = -ENOENT;
if (!bh)
goto end_rmdir;
inode = dentry->d_inode;
if (!empty_dir(inode)) {
retval = -ENOTEMPTY;
goto end_rmdir;
}
if (de->inode != inode->i_ino) {
retval = -ENOENT;
goto end_rmdir;
}
if (inode->i_nlink != 2)
printk("empty directory has nlink!=2 (%d)\n",inode->i_nlink);
de->inode = 0;
dir->i_version = ++event;
mark_buffer_dirty(bh);
inode->i_nlink=0;
mark_inode_dirty(inode);
inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME;
dir->i_nlink--;
mark_inode_dirty(dir);
retval = 0;
end_rmdir:
brelse(bh);
return retval;
}
static int minix_unlink(struct inode * dir, struct dentry *dentry)
{
int retval;
struct inode * inode;
struct buffer_head * bh;
struct minix_dir_entry * de;
retval = -ENOENT;
inode = dentry->d_inode;
bh = minix_find_entry(dir, dentry->d_name.name,
dentry->d_name.len, &de);
if (!bh || de->inode != inode->i_ino)
goto end_unlink;
if (!inode->i_nlink) {
printk("Deleting nonexistent file (%s:%lu), %d\n",
kdevname(inode->i_dev),
inode->i_ino, inode->i_nlink);
inode->i_nlink=1;
}
de->inode = 0;
dir->i_version = ++event;
mark_buffer_dirty(bh);
dir->i_ctime = dir->i_mtime = CURRENT_TIME;
mark_inode_dirty(dir);
inode->i_nlink--;
inode->i_ctime = dir->i_ctime;
mark_inode_dirty(inode);
retval = 0;
end_unlink:
brelse(bh);
return retval;
}
static int minix_symlink(struct inode * dir, struct dentry *dentry,
const char * symname)
{
struct minix_dir_entry * de;
struct inode * inode = NULL;
struct buffer_head * bh = NULL;
int i;
int err;
err = -ENAMETOOLONG;
i = strlen(symname)+1;
if (i>1024)
goto out;
inode = minix_new_inode(dir, &err);
if (!inode)
goto out;
inode->i_mode = S_IFLNK | 0777;
inode->i_op = &page_symlink_inode_operations;
inode->i_mapping->a_ops = &minix_aops;
err = block_symlink(inode, symname, i);
if (err)
goto fail;
err = minix_add_entry(dir, dentry->d_name.name,
dentry->d_name.len, &bh, &de);
if (err)
goto fail;
de->inode = inode->i_ino;
mark_buffer_dirty(bh);
brelse(bh);
d_instantiate(dentry, inode);
out:
return err;
fail:
inode->i_nlink--;
mark_inode_dirty(inode);
iput(inode);
goto out;
}
static int minix_link(struct dentry * old_dentry, struct inode * dir,
struct dentry *dentry)
{
int error;
struct inode *inode = old_dentry->d_inode;
struct minix_dir_entry * de;
struct buffer_head * bh;
if (S_ISDIR(inode->i_mode))
return -EPERM;
if (inode->i_nlink >= inode->i_sb->u.minix_sb.s_link_max)
return -EMLINK;
error = minix_add_entry(dir, dentry->d_name.name,
dentry->d_name.len, &bh, &de);
if (error) {
brelse(bh);
return error;
}
de->inode = inode->i_ino;
mark_buffer_dirty(bh);
brelse(bh);
inode->i_nlink++;
inode->i_ctime = CURRENT_TIME;
mark_inode_dirty(inode);
atomic_inc(&inode->i_count);
d_instantiate(dentry, inode);
return 0;
}
#define PARENT_INO(buffer) \
(((struct minix_dir_entry *) ((buffer)+info->s_dirsize))->inode)
/*
* Anybody can rename anything with this: the permission checks are left to the
* higher-level routines.
*/
static int minix_rename(struct inode * old_dir, struct dentry *old_dentry,
struct inode * new_dir, struct dentry *new_dentry)
{
struct inode * old_inode, * new_inode;
struct buffer_head * old_bh, * new_bh, * dir_bh;
struct minix_dir_entry * old_de, * new_de;
struct minix_sb_info * info;
int retval;
info = &old_dir->i_sb->u.minix_sb;
new_bh = dir_bh = NULL;
old_inode = old_dentry->d_inode;
new_inode = new_dentry->d_inode;
old_bh = minix_find_entry(old_dir, old_dentry->d_name.name,
old_dentry->d_name.len, &old_de);
retval = -ENOENT;
if (!old_bh || old_de->inode != old_inode->i_ino)
goto end_rename;
retval = -EPERM;
new_bh = minix_find_entry(new_dir, new_dentry->d_name.name,
new_dentry->d_name.len, &new_de);
if (new_bh) {
if (!new_inode) {
brelse(new_bh);
new_bh = NULL;
}
}
if (S_ISDIR(old_inode->i_mode)) {
if (new_inode) {
retval = -ENOTEMPTY;
if (!empty_dir(new_inode))
goto end_rename;
}
retval = -EIO;
dir_bh = minix_bread(old_inode,0,0);
if (!dir_bh)
goto end_rename;
if (PARENT_INO(dir_bh->b_data) != old_dir->i_ino)
goto end_rename;
retval = -EMLINK;
if (!new_inode && new_dir != old_dir &&
new_dir->i_nlink >= info->s_link_max)
goto end_rename;
}
if (!new_bh) {
retval = minix_add_entry(new_dir,
new_dentry->d_name.name,
new_dentry->d_name.len,
&new_bh, &new_de);
if (retval)
goto end_rename;
}
/* ok, that's it */
new_de->inode = old_inode->i_ino;
old_de->inode = 0;
old_dir->i_ctime = old_dir->i_mtime = CURRENT_TIME;
old_dir->i_version = ++event;
mark_inode_dirty(old_dir);
new_dir->i_ctime = new_dir->i_mtime = CURRENT_TIME;
new_dir->i_version = ++event;
mark_inode_dirty(new_dir);
if (new_inode) {
new_inode->i_nlink--;
new_inode->i_ctime = CURRENT_TIME;
mark_inode_dirty(new_inode);
}
mark_buffer_dirty(old_bh);
mark_buffer_dirty(new_bh);
if (dir_bh) {
PARENT_INO(dir_bh->b_data) = new_dir->i_ino;
mark_buffer_dirty(dir_bh);
old_dir->i_nlink--;
mark_inode_dirty(old_dir);
if (new_inode) {
new_inode->i_nlink--;
mark_inode_dirty(new_inode);
} else {
new_dir->i_nlink++;
mark_inode_dirty(new_dir);
}
}
retval = 0;
end_rename:
brelse(dir_bh);
brelse(old_bh);
brelse(new_bh);
return retval;
}
/*
* directories can handle most operations...
*/
struct inode_operations minix_dir_inode_operations = {
create: minix_create,
lookup: minix_lookup,
link: minix_link,
unlink: minix_unlink,
symlink: minix_symlink,
mkdir: minix_mkdir,
rmdir: minix_rmdir,
mknod: minix_mknod,
rename: minix_rename,
};