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/*
* mount.c - operations for initializing and mounting sysfs.
*/
#define DEBUG
#include <linux/fs.h>
#include <linux/mount.h>
#include <linux/pagemap.h>
#include <linux/init.h>
#include <asm/semaphore.h>
#include "sysfs.h"
/* Random magic number */
#define SYSFS_MAGIC 0x62656572
struct vfsmount *sysfs_mount;
struct super_block * sysfs_sb = NULL;
struct kmem_cache *sysfs_dir_cachep;
static const struct super_operations sysfs_ops = {
.statfs = simple_statfs,
.drop_inode = sysfs_delete_inode,
};
struct sysfs_dirent sysfs_root = {
.s_count = ATOMIC_INIT(1),
.s_flags = SYSFS_ROOT,
.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;
sysfs_sb = sb;
/* get root inode, initialize and unlock it */
inode = sysfs_get_inode(&sysfs_root);
if (!inode) {
pr_debug("sysfs: could not get root inode\n");
return -ENOMEM;
}
inode->i_op = &sysfs_dir_inode_operations;
inode->i_fop = &sysfs_dir_operations;
inc_nlink(inode); /* directory, account for "." */
unlock_new_inode(inode);
/* instantiate and link root dentry */
root = d_alloc_root(inode);
if (!root) {
pr_debug("%s: could not get root dentry!\n",__FUNCTION__);
iput(inode);
return -ENOMEM;
}
sysfs_root.s_dentry = root;
root->d_fsdata = &sysfs_root;
sb->s_root = root;
return 0;
}
static int sysfs_get_sb(struct file_system_type *fs_type,
int flags, const char *dev_name, void *data, struct vfsmount *mnt)
{
return get_sb_single(fs_type, flags, data, sysfs_fill_super, mnt);
}
static struct file_system_type sysfs_fs_type = {
.name = "sysfs",
.get_sb = sysfs_get_sb,
.kill_sb = kill_litter_super,
};
int __init sysfs_init(void)
{
int err = -ENOMEM;
sysfs_dir_cachep = kmem_cache_create("sysfs_dir_cache",
sizeof(struct sysfs_dirent),
0, 0, NULL, NULL);
if (!sysfs_dir_cachep)
goto out;
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;
}
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