- 根目录:
- fs
- sysv
- namei.c
/*
* linux/fs/sysv/namei.c
*
* minix/namei.c
* Copyright (C) 1991, 1992 Linus Torvalds
*
* coh/namei.c
* Copyright (C) 1993 Pascal Haible, Bruno Haible
*
* sysv/namei.c
* Copyright (C) 1993 Bruno Haible
* Copyright (C) 1997, 1998 Krzysztof G. Baranowski
*/
#include <linux/pagemap.h>
#include "sysv.h"
static int add_nondir(struct dentry *dentry, struct inode *inode)
{
int err = sysv_add_link(dentry, inode);
if (!err) {
d_instantiate(dentry, inode);
return 0;
}
inode_dec_link_count(inode);
iput(inode);
return err;
}
static int sysv_hash(const struct dentry *dentry, const struct inode *inode,
struct qstr *qstr)
{
/* Truncate the name in place, avoids having to define a compare
function. */
if (qstr->len > SYSV_NAMELEN) {
qstr->len = SYSV_NAMELEN;
qstr->hash = full_name_hash(qstr->name, qstr->len);
}
return 0;
}
const struct dentry_operations sysv_dentry_operations = {
.d_hash = sysv_hash,
};
static struct dentry *sysv_lookup(struct inode * dir, struct dentry * dentry, struct nameidata *nd)
{
struct inode * inode = NULL;
ino_t ino;
if (dentry->d_name.len > SYSV_NAMELEN)
return ERR_PTR(-ENAMETOOLONG);
ino = sysv_inode_by_name(dentry);
if (ino) {
inode = sysv_iget(dir->i_sb, ino);
if (IS_ERR(inode))
return ERR_CAST(inode);
}
d_add(dentry, inode);
return NULL;
}
static int sysv_mknod(struct inode * dir, struct dentry * dentry, umode_t mode, dev_t rdev)
{
struct inode * inode;
int err;
if (!old_valid_dev(rdev))
return -EINVAL;
inode = sysv_new_inode(dir, mode);
err = PTR_ERR(inode);
if (!IS_ERR(inode)) {
sysv_set_inode(inode, rdev);
mark_inode_dirty(inode);
err = add_nondir(dentry, inode);
}
return err;
}
static int sysv_create(struct inode * dir, struct dentry * dentry, umode_t mode, struct nameidata *nd)
{
return sysv_mknod(dir, dentry, mode, 0);
}
static int sysv_symlink(struct inode * dir, struct dentry * dentry,
const char * symname)
{
int err = -ENAMETOOLONG;
int l = strlen(symname)+1;
struct inode * inode;
if (l > dir->i_sb->s_blocksize)
goto out;
inode = sysv_new_inode(dir, S_IFLNK|0777);
err = PTR_ERR(inode);
if (IS_ERR(inode))
goto out;
sysv_set_inode(inode, 0);
err = page_symlink(inode, symname, l);
if (err)
goto out_fail;
mark_inode_dirty(inode);
err = add_nondir(dentry, inode);
out:
return err;
out_fail:
inode_dec_link_count(inode);
iput(inode);
goto out;
}
static int sysv_link(struct dentry * old_dentry, struct inode * dir,
struct dentry * dentry)
{
struct inode *inode = old_dentry->d_inode;
if (inode->i_nlink >= SYSV_SB(inode->i_sb)->s_link_max)
return -EMLINK;
inode->i_ctime = CURRENT_TIME_SEC;
inode_inc_link_count(inode);
ihold(inode);
return add_nondir(dentry, inode);
}
static int sysv_mkdir(struct inode * dir, struct dentry *dentry, umode_t mode)
{
struct inode * inode;
int err = -EMLINK;
if (dir->i_nlink >= SYSV_SB(dir->i_sb)->s_link_max)
goto out;
inode_inc_link_count(dir);
inode = sysv_new_inode(dir, S_IFDIR|mode);
err = PTR_ERR(inode);
if (IS_ERR(inode))
goto out_dir;
sysv_set_inode(inode, 0);
inode_inc_link_count(inode);
err = sysv_make_empty(inode, dir);
if (err)
goto out_fail;
err = sysv_add_link(dentry, inode);
if (err)
goto out_fail;
d_instantiate(dentry, inode);
out:
return err;
out_fail:
inode_dec_link_count(inode);
inode_dec_link_count(inode);
iput(inode);
out_dir:
inode_dec_link_count(dir);
goto out;
}
static int sysv_unlink(struct inode * dir, struct dentry * dentry)
{
struct inode * inode = dentry->d_inode;
struct page * page;
struct sysv_dir_entry * de;
int err = -ENOENT;
de = sysv_find_entry(dentry, &page);
if (!de)
goto out;
err = sysv_delete_entry (de, page);
if (err)
goto out;
inode->i_ctime = dir->i_ctime;
inode_dec_link_count(inode);
out:
return err;
}
static int sysv_rmdir(struct inode * dir, struct dentry * dentry)
{
struct inode *inode = dentry->d_inode;
int err = -ENOTEMPTY;
if (sysv_empty_dir(inode)) {
err = sysv_unlink(dir, dentry);
if (!err) {
inode->i_size = 0;
inode_dec_link_count(inode);
inode_dec_link_count(dir);
}
}
return err;
}
/*
* Anybody can rename anything with this: the permission checks are left to the
* higher-level routines.
*/
static int sysv_rename(struct inode * old_dir, struct dentry * old_dentry,
struct inode * new_dir, struct dentry * new_dentry)
{
struct inode * old_inode = old_dentry->d_inode;
struct inode * new_inode = new_dentry->d_inode;
struct page * dir_page = NULL;
struct sysv_dir_entry * dir_de = NULL;
struct page * old_page;
struct sysv_dir_entry * old_de;
int err = -ENOENT;
old_de = sysv_find_entry(old_dentry, &old_page);
if (!old_de)
goto out;
if (S_ISDIR(old_inode->i_mode)) {
err = -EIO;
dir_de = sysv_dotdot(old_inode, &dir_page);
if (!dir_de)
goto out_old;
}
if (new_inode) {
struct page * new_page;
struct sysv_dir_entry * new_de;
err = -ENOTEMPTY;
if (dir_de && !sysv_empty_dir(new_inode))
goto out_dir;
err = -ENOENT;
new_de = sysv_find_entry(new_dentry, &new_page);
if (!new_de)
goto out_dir;
sysv_set_link(new_de, new_page, old_inode);
new_inode->i_ctime = CURRENT_TIME_SEC;
if (dir_de)
drop_nlink(new_inode);
inode_dec_link_count(new_inode);
} else {
if (dir_de) {
err = -EMLINK;
if (new_dir->i_nlink >= SYSV_SB(new_dir->i_sb)->s_link_max)
goto out_dir;
}
err = sysv_add_link(new_dentry, old_inode);
if (err)
goto out_dir;
if (dir_de)
inode_inc_link_count(new_dir);
}
sysv_delete_entry(old_de, old_page);
mark_inode_dirty(old_inode);
if (dir_de) {
sysv_set_link(dir_de, dir_page, new_dir);
inode_dec_link_count(old_dir);
}
return 0;
out_dir:
if (dir_de) {
kunmap(dir_page);
page_cache_release(dir_page);
}
out_old:
kunmap(old_page);
page_cache_release(old_page);
out:
return err;
}
/*
* directories can handle most operations...
*/
const struct inode_operations sysv_dir_inode_operations = {
.create = sysv_create,
.lookup = sysv_lookup,
.link = sysv_link,
.unlink = sysv_unlink,
.symlink = sysv_symlink,
.mkdir = sysv_mkdir,
.rmdir = sysv_rmdir,
.mknod = sysv_mknod,
.rename = sysv_rename,
.getattr = sysv_getattr,
};