fat: mark fs as dirty on mount and clean on umount

There is no documented methods to mark FAT as dirty.  Unofficially MS
started to use reserved Byte in boot sector for this purpose, at least
since Win 2000.  With Win 7 user is warned if fs is dirty and asked to
clean it.

Different versions of Win, handle it in different ways, but always have
same meaning:

- Win 2000 and XP, set it on write operations and
  remove it after operation was finnished
- Win 7, set dirty flag on first write and remove it on umount.

We will do it as follows:

- set dirty flag on mount. If fs was initially dirty, warn user,
  remember it and do not do any changes to boot sector.
- clean it on umount. If fs was initially dirty, leave it dirty.
- do not do any thing if fs mounted read-only.
- TODO: leave fs dirty if we found some error after mount.

Signed-off-by: Oleksij Rempel <bug-track@fisher-privat.net>
Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Oleksij Rempel
2013-02-27 17:03:09 -08:00
committed by Linus Torvalds
parent 6b46419b04
commit b88a105802
3 changed files with 70 additions and 0 deletions

View File

@@ -87,6 +87,8 @@
#define IS_FSINFO(x) (le32_to_cpu((x)->signature1) == FAT_FSINFO_SIG1 \
&& le32_to_cpu((x)->signature2) == FAT_FSINFO_SIG2)
#define FAT_STATE_DIRTY 0x01
struct __fat_dirent {
long d_ino;
__kernel_off_t d_off;