Linux-2.6.12-rc2
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!
This commit is contained in:
Linus Torvalds
246
fs/ramfs/inode.c
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246
fs/ramfs/inode.c
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/*
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* Resizable simple ram filesystem for Linux.
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*
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* Copyright (C) 2000 Linus Torvalds.
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* 2000 Transmeta Corp.
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*
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* Usage limits added by David Gibson, Linuxcare Australia.
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* This file is released under the GPL.
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*/
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/*
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* NOTE! This filesystem is probably most useful
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* not as a real filesystem, but as an example of
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* how virtual filesystems can be written.
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*
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* It doesn't get much simpler than this. Consider
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* that this file implements the full semantics of
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* a POSIX-compliant read-write filesystem.
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*
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* Note in particular how the filesystem does not
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* need to implement any data structures of its own
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* to keep track of the virtual data: using the VFS
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* caches is sufficient.
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*/
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#include <linux/module.h>
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#include <linux/fs.h>
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#include <linux/pagemap.h>
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#include <linux/highmem.h>
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#include <linux/init.h>
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#include <linux/string.h>
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#include <linux/smp_lock.h>
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#include <linux/backing-dev.h>
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#include <linux/ramfs.h>
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#include <asm/uaccess.h>
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/* some random number */
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#define RAMFS_MAGIC 0x858458f6
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static struct super_operations ramfs_ops;
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static struct address_space_operations ramfs_aops;
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static struct inode_operations ramfs_file_inode_operations;
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static struct inode_operations ramfs_dir_inode_operations;
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static struct backing_dev_info ramfs_backing_dev_info = {
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.ra_pages = 0, /* No readahead */
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.capabilities = BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_WRITEBACK |
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BDI_CAP_MAP_DIRECT | BDI_CAP_MAP_COPY |
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BDI_CAP_READ_MAP | BDI_CAP_WRITE_MAP | BDI_CAP_EXEC_MAP,
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};
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struct inode *ramfs_get_inode(struct super_block *sb, int mode, dev_t dev)
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{
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struct inode * inode = new_inode(sb);
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if (inode) {
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inode->i_mode = mode;
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inode->i_uid = current->fsuid;
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inode->i_gid = current->fsgid;
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inode->i_blksize = PAGE_CACHE_SIZE;
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inode->i_blocks = 0;
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inode->i_mapping->a_ops = &ramfs_aops;
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inode->i_mapping->backing_dev_info = &ramfs_backing_dev_info;
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inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
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switch (mode & S_IFMT) {
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default:
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init_special_inode(inode, mode, dev);
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break;
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case S_IFREG:
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inode->i_op = &ramfs_file_inode_operations;
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inode->i_fop = &ramfs_file_operations;
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break;
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case S_IFDIR:
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inode->i_op = &ramfs_dir_inode_operations;
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inode->i_fop = &simple_dir_operations;
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/* directory inodes start off with i_nlink == 2 (for "." entry) */
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inode->i_nlink++;
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break;
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case S_IFLNK:
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inode->i_op = &page_symlink_inode_operations;
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break;
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}
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}
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return inode;
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}
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/*
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* File creation. Allocate an inode, and we're done..
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*/
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/* SMP-safe */
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static int
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ramfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
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{
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struct inode * inode = ramfs_get_inode(dir->i_sb, mode, dev);
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int error = -ENOSPC;
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if (inode) {
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if (dir->i_mode & S_ISGID) {
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inode->i_gid = dir->i_gid;
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if (S_ISDIR(mode))
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inode->i_mode |= S_ISGID;
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}
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d_instantiate(dentry, inode);
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dget(dentry); /* Extra count - pin the dentry in core */
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error = 0;
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}
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return error;
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}
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static int ramfs_mkdir(struct inode * dir, struct dentry * dentry, int mode)
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{
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int retval = ramfs_mknod(dir, dentry, mode | S_IFDIR, 0);
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if (!retval)
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dir->i_nlink++;
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return retval;
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}
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static int ramfs_create(struct inode *dir, struct dentry *dentry, int mode, struct nameidata *nd)
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{
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return ramfs_mknod(dir, dentry, mode | S_IFREG, 0);
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}
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static int ramfs_symlink(struct inode * dir, struct dentry *dentry, const char * symname)
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{
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struct inode *inode;
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int error = -ENOSPC;
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inode = ramfs_get_inode(dir->i_sb, S_IFLNK|S_IRWXUGO, 0);
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if (inode) {
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int l = strlen(symname)+1;
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error = page_symlink(inode, symname, l);
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if (!error) {
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if (dir->i_mode & S_ISGID)
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inode->i_gid = dir->i_gid;
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d_instantiate(dentry, inode);
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dget(dentry);
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} else
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iput(inode);
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}
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return error;
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}
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static struct address_space_operations ramfs_aops = {
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.readpage = simple_readpage,
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.prepare_write = simple_prepare_write,
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.commit_write = simple_commit_write
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};
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struct file_operations ramfs_file_operations = {
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.read = generic_file_read,
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.write = generic_file_write,
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.mmap = generic_file_mmap,
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.fsync = simple_sync_file,
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.sendfile = generic_file_sendfile,
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.llseek = generic_file_llseek,
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};
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static struct inode_operations ramfs_file_inode_operations = {
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.getattr = simple_getattr,
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};
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static struct inode_operations ramfs_dir_inode_operations = {
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.create = ramfs_create,
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.lookup = simple_lookup,
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.link = simple_link,
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.unlink = simple_unlink,
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.symlink = ramfs_symlink,
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.mkdir = ramfs_mkdir,
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.rmdir = simple_rmdir,
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.mknod = ramfs_mknod,
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.rename = simple_rename,
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};
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static struct super_operations ramfs_ops = {
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.statfs = simple_statfs,
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.drop_inode = generic_delete_inode,
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};
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static int ramfs_fill_super(struct super_block * sb, void * data, int silent)
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{
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struct inode * inode;
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struct dentry * root;
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sb->s_maxbytes = MAX_LFS_FILESIZE;
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sb->s_blocksize = PAGE_CACHE_SIZE;
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sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
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sb->s_magic = RAMFS_MAGIC;
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sb->s_op = &ramfs_ops;
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sb->s_time_gran = 1;
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inode = ramfs_get_inode(sb, S_IFDIR | 0755, 0);
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if (!inode)
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return -ENOMEM;
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root = d_alloc_root(inode);
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if (!root) {
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iput(inode);
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return -ENOMEM;
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}
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sb->s_root = root;
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return 0;
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}
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struct super_block *ramfs_get_sb(struct file_system_type *fs_type,
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int flags, const char *dev_name, void *data)
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{
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return get_sb_nodev(fs_type, flags, data, ramfs_fill_super);
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}
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static struct super_block *rootfs_get_sb(struct file_system_type *fs_type,
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int flags, const char *dev_name, void *data)
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{
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return get_sb_nodev(fs_type, flags|MS_NOUSER, data, ramfs_fill_super);
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}
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static struct file_system_type ramfs_fs_type = {
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.name = "ramfs",
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.get_sb = ramfs_get_sb,
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.kill_sb = kill_litter_super,
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};
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static struct file_system_type rootfs_fs_type = {
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.name = "rootfs",
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.get_sb = rootfs_get_sb,
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.kill_sb = kill_litter_super,
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};
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static int __init init_ramfs_fs(void)
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{
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return register_filesystem(&ramfs_fs_type);
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}
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static void __exit exit_ramfs_fs(void)
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{
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unregister_filesystem(&ramfs_fs_type);
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}
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module_init(init_ramfs_fs)
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module_exit(exit_ramfs_fs)
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int __init init_rootfs(void)
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{
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return register_filesystem(&rootfs_fs_type);
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}
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MODULE_LICENSE("GPL");
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