file-mmu.c 1.4 KB

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  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. * NOTE! This filesystem is probably most useful
  13. * not as a real filesystem, but as an example of
  14. * how virtual filesystems can be written.
  15. *
  16. * It doesn't get much simpler than this. Consider
  17. * that this file implements the full semantics of
  18. * a POSIX-compliant read-write filesystem.
  19. *
  20. * Note in particular how the filesystem does not
  21. * need to implement any data structures of its own
  22. * to keep track of the virtual data: using the VFS
  23. * caches is sufficient.
  24. */
  25. #include <linux/fs.h>
  26. #include <linux/mm.h>
  27. const struct address_space_operations ramfs_aops = {
  28. .readpage = simple_readpage,
  29. .prepare_write = simple_prepare_write,
  30. .commit_write = simple_commit_write,
  31. .set_page_dirty = __set_page_dirty_no_writeback,
  32. };
  33. const struct file_operations ramfs_file_operations = {
  34. .read = do_sync_read,
  35. .aio_read = generic_file_aio_read,
  36. .write = do_sync_write,
  37. .aio_write = generic_file_aio_write,
  38. .mmap = generic_file_mmap,
  39. .fsync = simple_sync_file,
  40. .sendfile = generic_file_sendfile,
  41. .llseek = generic_file_llseek,
  42. };
  43. const struct inode_operations ramfs_file_inode_operations = {
  44. .getattr = simple_getattr,
  45. };