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 30 const struct address_space_operations ramfs_aops = { 31 .readpage = simple_readpage, 32 .prepare_write = simple_prepare_write, 33 .commit_write = simple_commit_write, 34 .set_page_dirty = __set_page_dirty_no_writeback, 35 }; 36 37 const struct file_operations ramfs_file_operations = { 38 .read = do_sync_read, 39 .aio_read = generic_file_aio_read, 40 .write = do_sync_write, 41 .aio_write = generic_file_aio_write, 42 .mmap = generic_file_mmap, 43 .fsync = simple_sync_file, 44 .splice_read = generic_file_splice_read, 45 .llseek = generic_file_llseek, 46 }; 47 48 const struct inode_operations ramfs_file_inode_operations = { 49 .getattr = simple_getattr, 50 }; 51