mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-07 16:56:44 +07:00
1da177e4c3
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
247 lines
6.0 KiB
C
247 lines
6.0 KiB
C
/*
|
|
* Resizable simple ram filesystem for Linux.
|
|
*
|
|
* Copyright (C) 2000 Linus Torvalds.
|
|
* 2000 Transmeta Corp.
|
|
*
|
|
* Usage limits added by David Gibson, Linuxcare Australia.
|
|
* This file is released under the GPL.
|
|
*/
|
|
|
|
/*
|
|
* NOTE! This filesystem is probably most useful
|
|
* not as a real filesystem, but as an example of
|
|
* how virtual filesystems can be written.
|
|
*
|
|
* It doesn't get much simpler than this. Consider
|
|
* that this file implements the full semantics of
|
|
* a POSIX-compliant read-write filesystem.
|
|
*
|
|
* Note in particular how the filesystem does not
|
|
* need to implement any data structures of its own
|
|
* to keep track of the virtual data: using the VFS
|
|
* caches is sufficient.
|
|
*/
|
|
|
|
#include <linux/module.h>
|
|
#include <linux/fs.h>
|
|
#include <linux/pagemap.h>
|
|
#include <linux/highmem.h>
|
|
#include <linux/init.h>
|
|
#include <linux/string.h>
|
|
#include <linux/smp_lock.h>
|
|
#include <linux/backing-dev.h>
|
|
#include <linux/ramfs.h>
|
|
|
|
#include <asm/uaccess.h>
|
|
|
|
/* some random number */
|
|
#define RAMFS_MAGIC 0x858458f6
|
|
|
|
static struct super_operations ramfs_ops;
|
|
static struct address_space_operations ramfs_aops;
|
|
static struct inode_operations ramfs_file_inode_operations;
|
|
static struct inode_operations ramfs_dir_inode_operations;
|
|
|
|
static struct backing_dev_info ramfs_backing_dev_info = {
|
|
.ra_pages = 0, /* No readahead */
|
|
.capabilities = BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_WRITEBACK |
|
|
BDI_CAP_MAP_DIRECT | BDI_CAP_MAP_COPY |
|
|
BDI_CAP_READ_MAP | BDI_CAP_WRITE_MAP | BDI_CAP_EXEC_MAP,
|
|
};
|
|
|
|
struct inode *ramfs_get_inode(struct super_block *sb, int mode, dev_t dev)
|
|
{
|
|
struct inode * inode = new_inode(sb);
|
|
|
|
if (inode) {
|
|
inode->i_mode = mode;
|
|
inode->i_uid = current->fsuid;
|
|
inode->i_gid = current->fsgid;
|
|
inode->i_blksize = PAGE_CACHE_SIZE;
|
|
inode->i_blocks = 0;
|
|
inode->i_mapping->a_ops = &ramfs_aops;
|
|
inode->i_mapping->backing_dev_info = &ramfs_backing_dev_info;
|
|
inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
|
|
switch (mode & S_IFMT) {
|
|
default:
|
|
init_special_inode(inode, mode, dev);
|
|
break;
|
|
case S_IFREG:
|
|
inode->i_op = &ramfs_file_inode_operations;
|
|
inode->i_fop = &ramfs_file_operations;
|
|
break;
|
|
case S_IFDIR:
|
|
inode->i_op = &ramfs_dir_inode_operations;
|
|
inode->i_fop = &simple_dir_operations;
|
|
|
|
/* directory inodes start off with i_nlink == 2 (for "." entry) */
|
|
inode->i_nlink++;
|
|
break;
|
|
case S_IFLNK:
|
|
inode->i_op = &page_symlink_inode_operations;
|
|
break;
|
|
}
|
|
}
|
|
return inode;
|
|
}
|
|
|
|
/*
|
|
* File creation. Allocate an inode, and we're done..
|
|
*/
|
|
/* SMP-safe */
|
|
static int
|
|
ramfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
|
|
{
|
|
struct inode * inode = ramfs_get_inode(dir->i_sb, mode, dev);
|
|
int error = -ENOSPC;
|
|
|
|
if (inode) {
|
|
if (dir->i_mode & S_ISGID) {
|
|
inode->i_gid = dir->i_gid;
|
|
if (S_ISDIR(mode))
|
|
inode->i_mode |= S_ISGID;
|
|
}
|
|
d_instantiate(dentry, inode);
|
|
dget(dentry); /* Extra count - pin the dentry in core */
|
|
error = 0;
|
|
}
|
|
return error;
|
|
}
|
|
|
|
static int ramfs_mkdir(struct inode * dir, struct dentry * dentry, int mode)
|
|
{
|
|
int retval = ramfs_mknod(dir, dentry, mode | S_IFDIR, 0);
|
|
if (!retval)
|
|
dir->i_nlink++;
|
|
return retval;
|
|
}
|
|
|
|
static int ramfs_create(struct inode *dir, struct dentry *dentry, int mode, struct nameidata *nd)
|
|
{
|
|
return ramfs_mknod(dir, dentry, mode | S_IFREG, 0);
|
|
}
|
|
|
|
static int ramfs_symlink(struct inode * dir, struct dentry *dentry, const char * symname)
|
|
{
|
|
struct inode *inode;
|
|
int error = -ENOSPC;
|
|
|
|
inode = ramfs_get_inode(dir->i_sb, S_IFLNK|S_IRWXUGO, 0);
|
|
if (inode) {
|
|
int l = strlen(symname)+1;
|
|
error = page_symlink(inode, symname, l);
|
|
if (!error) {
|
|
if (dir->i_mode & S_ISGID)
|
|
inode->i_gid = dir->i_gid;
|
|
d_instantiate(dentry, inode);
|
|
dget(dentry);
|
|
} else
|
|
iput(inode);
|
|
}
|
|
return error;
|
|
}
|
|
|
|
static struct address_space_operations ramfs_aops = {
|
|
.readpage = simple_readpage,
|
|
.prepare_write = simple_prepare_write,
|
|
.commit_write = simple_commit_write
|
|
};
|
|
|
|
struct file_operations ramfs_file_operations = {
|
|
.read = generic_file_read,
|
|
.write = generic_file_write,
|
|
.mmap = generic_file_mmap,
|
|
.fsync = simple_sync_file,
|
|
.sendfile = generic_file_sendfile,
|
|
.llseek = generic_file_llseek,
|
|
};
|
|
|
|
static struct inode_operations ramfs_file_inode_operations = {
|
|
.getattr = simple_getattr,
|
|
};
|
|
|
|
static struct inode_operations ramfs_dir_inode_operations = {
|
|
.create = ramfs_create,
|
|
.lookup = simple_lookup,
|
|
.link = simple_link,
|
|
.unlink = simple_unlink,
|
|
.symlink = ramfs_symlink,
|
|
.mkdir = ramfs_mkdir,
|
|
.rmdir = simple_rmdir,
|
|
.mknod = ramfs_mknod,
|
|
.rename = simple_rename,
|
|
};
|
|
|
|
static struct super_operations ramfs_ops = {
|
|
.statfs = simple_statfs,
|
|
.drop_inode = generic_delete_inode,
|
|
};
|
|
|
|
static int ramfs_fill_super(struct super_block * sb, void * data, int silent)
|
|
{
|
|
struct inode * inode;
|
|
struct dentry * root;
|
|
|
|
sb->s_maxbytes = MAX_LFS_FILESIZE;
|
|
sb->s_blocksize = PAGE_CACHE_SIZE;
|
|
sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
|
|
sb->s_magic = RAMFS_MAGIC;
|
|
sb->s_op = &ramfs_ops;
|
|
sb->s_time_gran = 1;
|
|
inode = ramfs_get_inode(sb, S_IFDIR | 0755, 0);
|
|
if (!inode)
|
|
return -ENOMEM;
|
|
|
|
root = d_alloc_root(inode);
|
|
if (!root) {
|
|
iput(inode);
|
|
return -ENOMEM;
|
|
}
|
|
sb->s_root = root;
|
|
return 0;
|
|
}
|
|
|
|
struct super_block *ramfs_get_sb(struct file_system_type *fs_type,
|
|
int flags, const char *dev_name, void *data)
|
|
{
|
|
return get_sb_nodev(fs_type, flags, data, ramfs_fill_super);
|
|
}
|
|
|
|
static struct super_block *rootfs_get_sb(struct file_system_type *fs_type,
|
|
int flags, const char *dev_name, void *data)
|
|
{
|
|
return get_sb_nodev(fs_type, flags|MS_NOUSER, data, ramfs_fill_super);
|
|
}
|
|
|
|
static struct file_system_type ramfs_fs_type = {
|
|
.name = "ramfs",
|
|
.get_sb = ramfs_get_sb,
|
|
.kill_sb = kill_litter_super,
|
|
};
|
|
static struct file_system_type rootfs_fs_type = {
|
|
.name = "rootfs",
|
|
.get_sb = rootfs_get_sb,
|
|
.kill_sb = kill_litter_super,
|
|
};
|
|
|
|
static int __init init_ramfs_fs(void)
|
|
{
|
|
return register_filesystem(&ramfs_fs_type);
|
|
}
|
|
|
|
static void __exit exit_ramfs_fs(void)
|
|
{
|
|
unregister_filesystem(&ramfs_fs_type);
|
|
}
|
|
|
|
module_init(init_ramfs_fs)
|
|
module_exit(exit_ramfs_fs)
|
|
|
|
int __init init_rootfs(void)
|
|
{
|
|
return register_filesystem(&rootfs_fs_type);
|
|
}
|
|
|
|
MODULE_LICENSE("GPL");
|