linux/fs/exofs/namei.c
Al Viro 8de5277879 vfs: check i_nlink limits in vfs_{mkdir,rename_dir,link}
New field of struct super_block - ->s_max_links.  Maximal allowed
value of ->i_nlink or 0; in the latter case all checks still need
to be done in ->link/->mkdir/->rename instances.  Note that this
limit applies both to directoris and to non-directories.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-03-20 21:29:32 -04:00

321 lines
7.2 KiB
C

/*
* Copyright (C) 2005, 2006
* Avishay Traeger (avishay@gmail.com)
* Copyright (C) 2008, 2009
* Boaz Harrosh <bharrosh@panasas.com>
*
* Copyrights for code taken from ext2:
* Copyright (C) 1992, 1993, 1994, 1995
* Remy Card (card@masi.ibp.fr)
* Laboratoire MASI - Institut Blaise Pascal
* Universite Pierre et Marie Curie (Paris VI)
* from
* linux/fs/minix/inode.c
* Copyright (C) 1991, 1992 Linus Torvalds
*
* This file is part of exofs.
*
* exofs is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation. Since it is based on ext2, and the only
* valid version of GPL for the Linux kernel is version 2, the only valid
* version of GPL for exofs is version 2.
*
* exofs is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with exofs; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "exofs.h"
static inline int exofs_add_nondir(struct dentry *dentry, struct inode *inode)
{
int err = exofs_add_link(dentry, inode);
if (!err) {
d_instantiate(dentry, inode);
return 0;
}
inode_dec_link_count(inode);
iput(inode);
return err;
}
static struct dentry *exofs_lookup(struct inode *dir, struct dentry *dentry,
struct nameidata *nd)
{
struct inode *inode;
ino_t ino;
if (dentry->d_name.len > EXOFS_NAME_LEN)
return ERR_PTR(-ENAMETOOLONG);
ino = exofs_inode_by_name(dir, dentry);
inode = ino ? exofs_iget(dir->i_sb, ino) : NULL;
return d_splice_alias(inode, dentry);
}
static int exofs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
struct nameidata *nd)
{
struct inode *inode = exofs_new_inode(dir, mode);
int err = PTR_ERR(inode);
if (!IS_ERR(inode)) {
inode->i_op = &exofs_file_inode_operations;
inode->i_fop = &exofs_file_operations;
inode->i_mapping->a_ops = &exofs_aops;
mark_inode_dirty(inode);
err = exofs_add_nondir(dentry, inode);
}
return err;
}
static int exofs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode,
dev_t rdev)
{
struct inode *inode;
int err;
if (!new_valid_dev(rdev))
return -EINVAL;
inode = exofs_new_inode(dir, mode);
err = PTR_ERR(inode);
if (!IS_ERR(inode)) {
init_special_inode(inode, inode->i_mode, rdev);
mark_inode_dirty(inode);
err = exofs_add_nondir(dentry, inode);
}
return err;
}
static int exofs_symlink(struct inode *dir, struct dentry *dentry,
const char *symname)
{
struct super_block *sb = dir->i_sb;
int err = -ENAMETOOLONG;
unsigned l = strlen(symname)+1;
struct inode *inode;
struct exofs_i_info *oi;
if (l > sb->s_blocksize)
goto out;
inode = exofs_new_inode(dir, S_IFLNK | S_IRWXUGO);
err = PTR_ERR(inode);
if (IS_ERR(inode))
goto out;
oi = exofs_i(inode);
if (l > sizeof(oi->i_data)) {
/* slow symlink */
inode->i_op = &exofs_symlink_inode_operations;
inode->i_mapping->a_ops = &exofs_aops;
memset(oi->i_data, 0, sizeof(oi->i_data));
err = page_symlink(inode, symname, l);
if (err)
goto out_fail;
} else {
/* fast symlink */
inode->i_op = &exofs_fast_symlink_inode_operations;
memcpy(oi->i_data, symname, l);
inode->i_size = l-1;
}
mark_inode_dirty(inode);
err = exofs_add_nondir(dentry, inode);
out:
return err;
out_fail:
inode_dec_link_count(inode);
iput(inode);
goto out;
}
static int exofs_link(struct dentry *old_dentry, struct inode *dir,
struct dentry *dentry)
{
struct inode *inode = old_dentry->d_inode;
inode->i_ctime = CURRENT_TIME;
inode_inc_link_count(inode);
ihold(inode);
return exofs_add_nondir(dentry, inode);
}
static int exofs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
{
struct inode *inode;
int err;
inode_inc_link_count(dir);
inode = exofs_new_inode(dir, S_IFDIR | mode);
err = PTR_ERR(inode);
if (IS_ERR(inode))
goto out_dir;
inode->i_op = &exofs_dir_inode_operations;
inode->i_fop = &exofs_dir_operations;
inode->i_mapping->a_ops = &exofs_aops;
inode_inc_link_count(inode);
err = exofs_make_empty(inode, dir);
if (err)
goto out_fail;
err = exofs_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 exofs_unlink(struct inode *dir, struct dentry *dentry)
{
struct inode *inode = dentry->d_inode;
struct exofs_dir_entry *de;
struct page *page;
int err = -ENOENT;
de = exofs_find_entry(dir, dentry, &page);
if (!de)
goto out;
err = exofs_delete_entry(de, page);
if (err)
goto out;
inode->i_ctime = dir->i_ctime;
inode_dec_link_count(inode);
err = 0;
out:
return err;
}
static int exofs_rmdir(struct inode *dir, struct dentry *dentry)
{
struct inode *inode = dentry->d_inode;
int err = -ENOTEMPTY;
if (exofs_empty_dir(inode)) {
err = exofs_unlink(dir, dentry);
if (!err) {
inode->i_size = 0;
inode_dec_link_count(inode);
inode_dec_link_count(dir);
}
}
return err;
}
static int exofs_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 exofs_dir_entry *dir_de = NULL;
struct page *old_page;
struct exofs_dir_entry *old_de;
int err = -ENOENT;
old_de = exofs_find_entry(old_dir, old_dentry, &old_page);
if (!old_de)
goto out;
if (S_ISDIR(old_inode->i_mode)) {
err = -EIO;
dir_de = exofs_dotdot(old_inode, &dir_page);
if (!dir_de)
goto out_old;
}
if (new_inode) {
struct page *new_page;
struct exofs_dir_entry *new_de;
err = -ENOTEMPTY;
if (dir_de && !exofs_empty_dir(new_inode))
goto out_dir;
err = -ENOENT;
new_de = exofs_find_entry(new_dir, new_dentry, &new_page);
if (!new_de)
goto out_dir;
err = exofs_set_link(new_dir, new_de, new_page, old_inode);
new_inode->i_ctime = CURRENT_TIME;
if (dir_de)
drop_nlink(new_inode);
inode_dec_link_count(new_inode);
if (err)
goto out_dir;
} else {
err = exofs_add_link(new_dentry, old_inode);
if (err)
goto out_dir;
if (dir_de)
inode_inc_link_count(new_dir);
}
old_inode->i_ctime = CURRENT_TIME;
exofs_delete_entry(old_de, old_page);
mark_inode_dirty(old_inode);
if (dir_de) {
err = exofs_set_link(old_inode, dir_de, dir_page, new_dir);
inode_dec_link_count(old_dir);
if (err)
goto out_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;
}
const struct inode_operations exofs_dir_inode_operations = {
.create = exofs_create,
.lookup = exofs_lookup,
.link = exofs_link,
.unlink = exofs_unlink,
.symlink = exofs_symlink,
.mkdir = exofs_mkdir,
.rmdir = exofs_rmdir,
.mknod = exofs_mknod,
.rename = exofs_rename,
.setattr = exofs_setattr,
};
const struct inode_operations exofs_special_inode_operations = {
.setattr = exofs_setattr,
};