release/src-rt-6.x.4708/linux/linux-2.6.36/fs/ramfs/file-mmu.c

   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 address_space_operations ramfs_aops = {
  34         .readpage       = simple_readpage,
  35         .write_begin    = simple_write_begin,
  36         .write_end      = simple_write_end,
  37         .set_page_dirty = __set_page_dirty_no_writeback,
  38 };
  39
  40 const struct file_operations ramfs_file_operations = {
  41         .read           = do_sync_read,
  42         .aio_read       = generic_file_aio_read,
  43         .write          = do_sync_write,
  44         .aio_write      = generic_file_aio_write,
  45         .mmap           = generic_file_mmap,
  46         .fsync          = noop_fsync,
  47         .splice_read    = generic_file_splice_read,
  48         .splice_write   = generic_file_splice_write,
  49         .llseek         = generic_file_llseek,
  50 };
  51
  52 const struct inode_operations ramfs_file_inode_operations = {
  53         .setattr        = simple_setattr,
  54         .getattr        = simple_getattr,
  55 };