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/*
* fs/sysfs/symlink.c - operations for initializing and mounting sysfs
*
* Copyright (c) 2001-3 Patrick Mochel
* Copyright (c) 2007 SUSE Linux Products GmbH
* Copyright (c) 2007 Tejun Heo <teheo@suse.de>
*
* This file is released under the GPLv2.
*
* Please see Documentation/filesystems/sysfs.txt for more information.
*/
#define DEBUG
#include <linux/fs.h>
#include <linux/mount.h>
#include <linux/pagemap.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/magic.h>
#include <linux/slab.h>
#include "sysfs.h"
static struct vfsmount *sysfs_mount;
struct kmem_cache *sysfs_dir_cachep;
static const struct super_operations sysfs_ops = {
.statfs = simple_statfs,
.drop_inode = generic_delete_inode,
.evict_inode = sysfs_evict_inode,
};
struct sysfs_dirent sysfs_root = {
.s_name = "",
.s_count = ATOMIC_INIT(1),
.s_flags = SYSFS_DIR | (KOBJ_NS_TYPE_NONE << SYSFS_NS_TYPE_SHIFT),
.s_mode = S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO,
.s_ino = 1,
};
static int sysfs_fill_super(struct super_block *sb, void *data, int silent)
{
struct inode *inode;
struct dentry *root;
sb->s_blocksize = PAGE_CACHE_SIZE;
sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
sb->s_magic = SYSFS_MAGIC;
sb->s_op = &sysfs_ops;
sb->s_time_gran = 1;
/* get root inode, initialize and unlock it */
mutex_lock(&sysfs_mutex);
inode = sysfs_get_inode(sb, &sysfs_root);
mutex_unlock(&sysfs_mutex);
if (!inode) {
pr_debug("sysfs: could not get root inode\n");
return -ENOMEM;
}
/* instantiate and link root dentry */
root = d_alloc_root(inode);
if (!root) {
pr_debug("%s: could not get root dentry!\n",__func__);
iput(inode);
return -ENOMEM;
}
root->d_fsdata = &sysfs_root;
sb->s_root = root;
return 0;
}
static int sysfs_test_super(struct super_block *sb, void *data)
{
struct sysfs_super_info *sb_info = sysfs_info(sb);
struct sysfs_super_info *info = data;
enum kobj_ns_type type;
int found = 1;
for (type = KOBJ_NS_TYPE_NONE; type < KOBJ_NS_TYPES; type++) {
if (sb_info->ns[type] != info->ns[type])
found = 0;
}
return found;
}
static int sysfs_set_super(struct super_block *sb, void *data)
{
int error;
error = set_anon_super(sb, data);
if (!error)
sb->s_fs_info = data;
return error;
}
static int sysfs_get_sb(struct file_system_type *fs_type,
int flags, const char *dev_name, void *data, struct vfsmount *mnt)
{
struct sysfs_super_info *info;
enum kobj_ns_type type;
struct super_block *sb;
int error;
error = -ENOMEM;
info = kzalloc(sizeof(*info), GFP_KERNEL);
if (!info)
goto out;
for (type = KOBJ_NS_TYPE_NONE; type < KOBJ_NS_TYPES; type++)
info->ns[type] = kobj_ns_current(type);
sb = sget(fs_type, sysfs_test_super, sysfs_set_super, info);
if (IS_ERR(sb) || sb->s_fs_info != info)
kfree(info);
if (IS_ERR(sb)) {
error = PTR_ERR(sb);
goto out;
}
if (!sb->s_root) {
sb->s_flags = flags;
error = sysfs_fill_super(sb, data, flags & MS_SILENT ? 1 : 0);
if (error) {
deactivate_locked_super(sb);
goto out;
}
sb->s_flags |= MS_ACTIVE;
}
simple_set_mnt(mnt, sb);
error = 0;
out:
return error;
}
static void sysfs_kill_sb(struct super_block *sb)
{
struct sysfs_super_info *info = sysfs_info(sb);
/* Remove the superblock from fs_supers/s_instances
* so we can't find it, before freeing sysfs_super_info.
*/
kill_anon_super(sb);
kfree(info);
}
static struct file_system_type sysfs_fs_type = {
.name = "sysfs",
.get_sb = sysfs_get_sb,
.kill_sb = sysfs_kill_sb,
};
void sysfs_exit_ns(enum kobj_ns_type type, const void *ns)
{
struct super_block *sb;
mutex_lock(&sysfs_mutex);
spin_lock(&sb_lock);
list_for_each_entry(sb, &sysfs_fs_type.fs_supers, s_instances) {
struct sysfs_super_info *info = sysfs_info(sb);
/*
* If we see a superblock on the fs_supers/s_instances
* list the unmount has not completed and sb->s_fs_info
* points to a valid struct sysfs_super_info.
*/
/* Ignore superblocks with the wrong ns */
if (info->ns[type] != ns)
continue;
info->ns[type] = NULL;
}
spin_unlock(&sb_lock);
mutex_unlock(&sysfs_mutex);
}
int __init sysfs_init(void)
{
int err = -ENOMEM;
sysfs_dir_cachep = kmem_cache_create("sysfs_dir_cache",
sizeof(struct sysfs_dirent),
0, 0, NULL);
if (!sysfs_dir_cachep)
goto out;
err = sysfs_inode_init();
if (err)
goto out_err;
err = register_filesystem(&sysfs_fs_type);
if (!err) {
sysfs_mount = kern_mount(&sysfs_fs_type);
if (IS_ERR(sysfs_mount)) {
printk(KERN_ERR "sysfs: could not mount!\n");
err = PTR_ERR(sysfs_mount);
sysfs_mount = NULL;
unregister_filesystem(&sysfs_fs_type);
goto out_err;
}
} else
goto out_err;
out:
return err;
out_err:
kmem_cache_destroy(sysfs_dir_cachep);
sysfs_dir_cachep = NULL;
goto out;
}
#undef sysfs_get
struct sysfs_dirent *sysfs_get(struct sysfs_dirent *sd)
{
return __sysfs_get(sd);
}
EXPORT_SYMBOL_GPL(sysfs_get);
#undef sysfs_put
void sysfs_put(struct sysfs_dirent *sd)
{
__sysfs_put(sd);
}
EXPORT_SYMBOL_GPL(sysfs_put);
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