1 /* file-mmu.c: ramfs MMU-based file operations 2 * 3 * Resizable simple ram filesystem for Linux. 4 * 5 * Copyright (C) 2000 Linus Torvalds. 6 * 2000 Transmeta Corp. 7 * 8 * Usage limits added by David Gibson, Linuxcare Australia. 9 * This file is released under the GPL. 10 */ 11 12 /* 13 * NOTE! This filesystem is probably most useful 14 * not as a real filesystem, but as an example of 15 * how virtual filesystems can be written. 16 * 17 * It doesn't get much simpler than this. Consider 18 * that this file implements the full semantics of 19 * a POSIX-compliant read-write filesystem. 20 * 21 * Note in particular how the filesystem does not 22 * need to implement any data structures of its own 23 * to keep track of the virtual data: using the VFS 24 * caches is sufficient. 25 */ 26 27 #include <linux/fs.h> 28 #include <linux/mm.h> 29 #include <linux/ramfs.h> 30 31 #include "internal.h" 32 33 const struct file_operations ramfs_file_operations = { 34 .read = new_sync_read, 35 .read_iter = generic_file_read_iter, 36 .write = new_sync_write, 37 .write_iter = generic_file_write_iter, 38 .mmap = generic_file_mmap, 39 .fsync = noop_fsync, 40 .splice_read = generic_file_splice_read, 41 .splice_write = iter_file_splice_write, 42 .llseek = generic_file_llseek, 43 }; 44 45 const struct inode_operations ramfs_file_inode_operations = { 46 .setattr = simple_setattr, 47 .getattr = simple_getattr, 48 }; 49