original development tree for Linux kernel GTP module; now long in mainline.
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/*
* Hypervisor filesystem for Linux on s390.
*
* Copyright IBM Corp. 2006, 2008
* Author(s): Michael Holzheu <holzheu@de.ibm.com>
*/
#define KMSG_COMPONENT "hypfs"
#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/namei.h>
#include <linux/vfs.h>
#include <linux/slab.h>
#include <linux/pagemap.h>
#include <linux/time.h>
#include <linux/parser.h>
#include <linux/sysfs.h>
#include <linux/module.h>
#include <linux/seq_file.h>
#include <linux/mount.h>
#include <asm/ebcdic.h>
#include "hypfs.h"
#define HYPFS_MAGIC 0x687970 /* ASCII 'hyp' */
#define TMP_SIZE 64 /* size of temporary buffers */
static struct dentry *hypfs_create_update_file(struct super_block *sb,
struct dentry *dir);
struct hypfs_sb_info {
kuid_t uid; /* uid used for files and dirs */
kgid_t gid; /* gid used for files and dirs */
struct dentry *update_file; /* file to trigger update */
time_t last_update; /* last update time in secs since 1970 */
struct mutex lock; /* lock to protect update process */
};
static const struct file_operations hypfs_file_ops;
static struct file_system_type hypfs_type;
static const struct super_operations hypfs_s_ops;
/* start of list of all dentries, which have to be deleted on update */
static struct dentry *hypfs_last_dentry;
static void hypfs_update_update(struct super_block *sb)
{
struct hypfs_sb_info *sb_info = sb->s_fs_info;
struct inode *inode = sb_info->update_file->d_inode;
sb_info->last_update = get_seconds();
inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
}
/* directory tree removal functions */
static void hypfs_add_dentry(struct dentry *dentry)
{
dentry->d_fsdata = hypfs_last_dentry;
hypfs_last_dentry = dentry;
}
static inline int hypfs_positive(struct dentry *dentry)
{
return dentry->d_inode && !d_unhashed(dentry);
}
static void hypfs_remove(struct dentry *dentry)
{
struct dentry *parent;
parent = dentry->d_parent;
mutex_lock(&parent->d_inode->i_mutex);
if (hypfs_positive(dentry)) {
if (S_ISDIR(dentry->d_inode->i_mode))
simple_rmdir(parent->d_inode, dentry);
else
simple_unlink(parent->d_inode, dentry);
}
d_delete(dentry);
dput(dentry);
mutex_unlock(&parent->d_inode->i_mutex);
}
static void hypfs_delete_tree(struct dentry *root)
{
while (hypfs_last_dentry) {
struct dentry *next_dentry;
next_dentry = hypfs_last_dentry->d_fsdata;
hypfs_remove(hypfs_last_dentry);
hypfs_last_dentry = next_dentry;
}
}
static struct inode *hypfs_make_inode(struct super_block *sb, umode_t mode)
{
struct inode *ret = new_inode(sb);
if (ret) {
struct hypfs_sb_info *hypfs_info = sb->s_fs_info;
ret->i_ino = get_next_ino();
ret->i_mode = mode;
ret->i_uid = hypfs_info->uid;
ret->i_gid = hypfs_info->gid;
ret->i_atime = ret->i_mtime = ret->i_ctime = CURRENT_TIME;
if (S_ISDIR(mode))
set_nlink(ret, 2);
}
return ret;
}
static void hypfs_evict_inode(struct inode *inode)
{
clear_inode(inode);
kfree(inode->i_private);
}
static int hypfs_open(struct inode *inode, struct file *filp)
{
char *data = file_inode(filp)->i_private;
struct hypfs_sb_info *fs_info;
if (filp->f_mode & FMODE_WRITE) {
if (!(inode->i_mode & S_IWUGO))
return -EACCES;
}
if (filp->f_mode & FMODE_READ) {
if (!(inode->i_mode & S_IRUGO))
return -EACCES;
}
fs_info = inode->i_sb->s_fs_info;
if(data) {
mutex_lock(&fs_info->lock);
filp->private_data = kstrdup(data, GFP_KERNEL);
if (!filp->private_data) {
mutex_unlock(&fs_info->lock);
return -ENOMEM;
}
mutex_unlock(&fs_info->lock);
}
return nonseekable_open(inode, filp);
}
static ssize_t hypfs_aio_read(struct kiocb *iocb, const struct iovec *iov,
unsigned long nr_segs, loff_t offset)
{
char *data;
ssize_t ret;
struct file *filp = iocb->ki_filp;
/* XXX: temporary */
char __user *buf = iov[0].iov_base;
size_t count = iov[0].iov_len;
if (nr_segs != 1)
return -EINVAL;
data = filp->private_data;
ret = simple_read_from_buffer(buf, count, &offset, data, strlen(data));
if (ret <= 0)
return ret;
iocb->ki_pos += ret;
file_accessed(filp);
return ret;
}
static ssize_t hypfs_aio_write(struct kiocb *iocb, const struct iovec *iov,
unsigned long nr_segs, loff_t offset)
{
int rc;
struct super_block *sb = file_inode(iocb->ki_filp)->i_sb;
struct hypfs_sb_info *fs_info = sb->s_fs_info;
size_t count = iov_length(iov, nr_segs);
/*
* Currently we only allow one update per second for two reasons:
* 1. diag 204 is VERY expensive
* 2. If several processes do updates in parallel and then read the
* hypfs data, the likelihood of collisions is reduced, if we restrict
* the minimum update interval. A collision occurs, if during the
* data gathering of one process another process triggers an update
* If the first process wants to ensure consistent data, it has
* to restart data collection in this case.
*/
mutex_lock(&fs_info->lock);
if (fs_info->last_update == get_seconds()) {
rc = -EBUSY;
goto out;
}
hypfs_delete_tree(sb->s_root);
if (MACHINE_IS_VM)
rc = hypfs_vm_create_files(sb, sb->s_root);
else
rc = hypfs_diag_create_files(sb, sb->s_root);
if (rc) {
pr_err("Updating the hypfs tree failed\n");
hypfs_delete_tree(sb->s_root);
goto out;
}
hypfs_update_update(sb);
rc = count;
out:
mutex_unlock(&fs_info->lock);
return rc;
}
static int hypfs_release(struct inode *inode, struct file *filp)
{
kfree(filp->private_data);
return 0;
}
enum { opt_uid, opt_gid, opt_err };
static const match_table_t hypfs_tokens = {
{opt_uid, "uid=%u"},
{opt_gid, "gid=%u"},
{opt_err, NULL}
};
static int hypfs_parse_options(char *options, struct super_block *sb)
{
char *str;
substring_t args[MAX_OPT_ARGS];
kuid_t uid;
kgid_t gid;
if (!options)
return 0;
while ((str = strsep(&options, ",")) != NULL) {
int token, option;
struct hypfs_sb_info *hypfs_info = sb->s_fs_info;
if (!*str)
continue;
token = match_token(str, hypfs_tokens, args);
switch (token) {
case opt_uid:
if (match_int(&args[0], &option))
return -EINVAL;
uid = make_kuid(current_user_ns(), option);
if (!uid_valid(uid))
return -EINVAL;
hypfs_info->uid = uid;
break;
case opt_gid:
if (match_int(&args[0], &option))
return -EINVAL;
gid = make_kgid(current_user_ns(), option);
if (!gid_valid(gid))
return -EINVAL;
hypfs_info->gid = gid;
break;
case opt_err:
default:
pr_err("%s is not a valid mount option\n", str);
return -EINVAL;
}
}
return 0;
}
static int hypfs_show_options(struct seq_file *s, struct dentry *root)
{
struct hypfs_sb_info *hypfs_info = root->d_sb->s_fs_info;
seq_printf(s, ",uid=%u", from_kuid_munged(&init_user_ns, hypfs_info->uid));
seq_printf(s, ",gid=%u", from_kgid_munged(&init_user_ns, hypfs_info->gid));
return 0;
}
static int hypfs_fill_super(struct super_block *sb, void *data, int silent)
{
struct inode *root_inode;
struct dentry *root_dentry;
int rc = 0;
struct hypfs_sb_info *sbi;
sbi = kzalloc(sizeof(struct hypfs_sb_info), GFP_KERNEL);
if (!sbi)
return -ENOMEM;
mutex_init(&sbi->lock);
sbi->uid = current_uid();
sbi->gid = current_gid();
sb->s_fs_info = sbi;
sb->s_blocksize = PAGE_CACHE_SIZE;
sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
sb->s_magic = HYPFS_MAGIC;
sb->s_op = &hypfs_s_ops;
if (hypfs_parse_options(data, sb))
return -EINVAL;
root_inode = hypfs_make_inode(sb, S_IFDIR | 0755);
if (!root_inode)
return -ENOMEM;
root_inode->i_op = &simple_dir_inode_operations;
root_inode->i_fop = &simple_dir_operations;
sb->s_root = root_dentry = d_make_root(root_inode);
if (!root_dentry)
return -ENOMEM;
if (MACHINE_IS_VM)
rc = hypfs_vm_create_files(sb, root_dentry);
else
rc = hypfs_diag_create_files(sb, root_dentry);
if (rc)
return rc;
sbi->update_file = hypfs_create_update_file(sb, root_dentry);
if (IS_ERR(sbi->update_file))
return PTR_ERR(sbi->update_file);
hypfs_update_update(sb);
pr_info("Hypervisor filesystem mounted\n");
return 0;
}
static struct dentry *hypfs_mount(struct file_system_type *fst, int flags,
const char *devname, void *data)
{
return mount_single(fst, flags, data, hypfs_fill_super);
}
static void hypfs_kill_super(struct super_block *sb)
{
struct hypfs_sb_info *sb_info = sb->s_fs_info;
if (sb->s_root)
hypfs_delete_tree(sb->s_root);
if (sb_info->update_file)
hypfs_remove(sb_info->update_file);
kfree(sb->s_fs_info);
sb->s_fs_info = NULL;
kill_litter_super(sb);
}
static struct dentry *hypfs_create_file(struct super_block *sb,
struct dentry *parent, const char *name,
char *data, umode_t mode)
{
struct dentry *dentry;
struct inode *inode;
mutex_lock(&parent->d_inode->i_mutex);
dentry = lookup_one_len(name, parent, strlen(name));
if (IS_ERR(dentry)) {
dentry = ERR_PTR(-ENOMEM);
goto fail;
}
inode = hypfs_make_inode(sb, mode);
if (!inode) {
dput(dentry);
dentry = ERR_PTR(-ENOMEM);
goto fail;
}
if (S_ISREG(mode)) {
inode->i_fop = &hypfs_file_ops;
if (data)
inode->i_size = strlen(data);
else
inode->i_size = 0;
} else if (S_ISDIR(mode)) {
inode->i_op = &simple_dir_inode_operations;
inode->i_fop = &simple_dir_operations;
inc_nlink(parent->d_inode);
} else
BUG();
inode->i_private = data;
d_instantiate(dentry, inode);
dget(dentry);
fail:
mutex_unlock(&parent->d_inode->i_mutex);
return dentry;
}
struct dentry *hypfs_mkdir(struct super_block *sb, struct dentry *parent,
const char *name)
{
struct dentry *dentry;
dentry = hypfs_create_file(sb, parent, name, NULL, S_IFDIR | DIR_MODE);
if (IS_ERR(dentry))
return dentry;
hypfs_add_dentry(dentry);
return dentry;
}
static struct dentry *hypfs_create_update_file(struct super_block *sb,
struct dentry *dir)
{
struct dentry *dentry;
dentry = hypfs_create_file(sb, dir, "update", NULL,
S_IFREG | UPDATE_FILE_MODE);
/*
* We do not put the update file on the 'delete' list with
* hypfs_add_dentry(), since it should not be removed when the tree
* is updated.
*/
return dentry;
}
struct dentry *hypfs_create_u64(struct super_block *sb, struct dentry *dir,
const char *name, __u64 value)
{
char *buffer;
char tmp[TMP_SIZE];
struct dentry *dentry;
snprintf(tmp, TMP_SIZE, "%llu\n", (unsigned long long int)value);
buffer = kstrdup(tmp, GFP_KERNEL);
if (!buffer)
return ERR_PTR(-ENOMEM);
dentry =
hypfs_create_file(sb, dir, name, buffer, S_IFREG | REG_FILE_MODE);
if (IS_ERR(dentry)) {
kfree(buffer);
return ERR_PTR(-ENOMEM);
}
hypfs_add_dentry(dentry);
return dentry;
}
struct dentry *hypfs_create_str(struct super_block *sb, struct dentry *dir,
const char *name, char *string)
{
char *buffer;
struct dentry *dentry;
buffer = kmalloc(strlen(string) + 2, GFP_KERNEL);
if (!buffer)
return ERR_PTR(-ENOMEM);
sprintf(buffer, "%s\n", string);
dentry =
hypfs_create_file(sb, dir, name, buffer, S_IFREG | REG_FILE_MODE);
if (IS_ERR(dentry)) {
kfree(buffer);
return ERR_PTR(-ENOMEM);
}
hypfs_add_dentry(dentry);
return dentry;
}
static const struct file_operations hypfs_file_ops = {
.open = hypfs_open,
.release = hypfs_release,
.read = do_sync_read,
.write = do_sync_write,
.aio_read = hypfs_aio_read,
.aio_write = hypfs_aio_write,
.llseek = no_llseek,
};
static struct file_system_type hypfs_type = {
.owner = THIS_MODULE,
.name = "s390_hypfs",
.mount = hypfs_mount,
.kill_sb = hypfs_kill_super
};
MODULE_ALIAS_FS("s390_hypfs");
static const struct super_operations hypfs_s_ops = {
.statfs = simple_statfs,
.evict_inode = hypfs_evict_inode,
.show_options = hypfs_show_options,
};
static struct kobject *s390_kobj;
static int __init hypfs_init(void)
{
int rc;
rc = hypfs_dbfs_init();
if (rc)
return rc;
if (hypfs_diag_init()) {
rc = -ENODATA;
goto fail_dbfs_exit;
}
if (hypfs_vm_init()) {
rc = -ENODATA;
goto fail_hypfs_diag_exit;
}
s390_kobj = kobject_create_and_add("s390", hypervisor_kobj);
if (!s390_kobj) {
rc = -ENOMEM;
goto fail_hypfs_vm_exit;
}
rc = register_filesystem(&hypfs_type);
if (rc)
goto fail_filesystem;
return 0;
fail_filesystem:
kobject_put(s390_kobj);
fail_hypfs_vm_exit:
hypfs_vm_exit();
fail_hypfs_diag_exit:
hypfs_diag_exit();
fail_dbfs_exit:
hypfs_dbfs_exit();
pr_err("Initialization of hypfs failed with rc=%i\n", rc);
return rc;
}
static void __exit hypfs_exit(void)
{
hypfs_diag_exit();
hypfs_vm_exit();
hypfs_dbfs_exit();
unregister_filesystem(&hypfs_type);
kobject_put(s390_kobj);
}
module_init(hypfs_init)
module_exit(hypfs_exit)
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Michael Holzheu <holzheu@de.ibm.com>");
MODULE_DESCRIPTION("s390 Hypervisor Filesystem");