booked-page-flag.patch

   1 [RFC] delayed allocation for ext4
   2
   3 From:  Alex Tomas <alex@clusterfs.com>
   4
   5 Adds PG_booked bit to page->flags.  It's used in delayed allocation to
   6 mark space is already reserved for page (including possible metadata)
   7
   8 Signed-off-by: Alex Tomas <alex@clusterfs.com>
   9 ---
  10 ---
  11  include/linux/page-flags.h |    5 +++++
  12  1 file changed, 5 insertions(+)
  13
  14 Index: linux-2.6.23-rc2/include/linux/page-flags.h
  15 ===================================================================
  16 --- linux-2.6.23-rc2.orig/include/linux/page-flags.h    2007-08-06 22:18:09.000000000 -0700
  17 +++ linux-2.6.23-rc2/include/linux/page-flags.h 2007-08-06 22:18:57.000000000 -0700
  18 @@ -89,6 +89,7 @@
  19  #define PG_mappedtodisk                16      /* Has blocks allocated on-disk */
  20  #define PG_reclaim             17      /* To be reclaimed asap */
  21  #define PG_buddy               19      /* Page is free, on buddy lists */
  22 +#define PG_booked              20      /* Has blocks reserved on-disk */
  23
  24  /* PG_readahead is only used for file reads; PG_reclaim is only for writes */
  25  #define PG_readahead           PG_reclaim /* Reminder to do async read-ahead */
  26 @@ -211,6 +212,10 @@ static inline void SetPageUptodate(struc
  27  #define SetPageReadahead(page) set_bit(PG_readahead, &(page)->flags)
  28  #define ClearPageReadahead(page) clear_bit(PG_readahead, &(page)->flags)
  29
  30 +#define PageBooked(page)       test_bit(PG_booked, &(page)->flags)
  31 +#define SetPageBooked(page)    set_bit(PG_booked, &(page)->flags)
  32 +#define ClearPageBooked(page)  clear_bit(PG_booked, &(page)->flags)
  33 +
  34  #define PageReclaim(page)      test_bit(PG_reclaim, &(page)->flags)
  35  #define SetPageReclaim(page)   set_bit(PG_reclaim, &(page)->flags)
  36  #define ClearPageReclaim(page) clear_bit(PG_reclaim, &(page)->flags)