[PATCH] md: replace magic numbers in sb_dirty with well defined bit flags

Instead of magic numbers (0,1,2,3) in sb_dirty, we have
some flags instead:
MD_CHANGE_DEVS
   Some device state has changed requiring superblock update
   on all devices.
MD_CHANGE_CLEAN
   The array has transitions from 'clean' to 'dirty' or back,
   requiring a superblock update on active devices, but possibly
   not on spares
MD_CHANGE_PENDING
   A superblock update is underway.

We wait for an update to complete by waiting for all flags to be clear.  A
flag can be set at any time, even during an update, without risk that the
change will be lost.

Stop exporting md_update_sb - isn't needed.

Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 1 insertions, 1 deletions

diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 7bf5ce281c4d..85e3df2d268a 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -960,7 +960,7 @@ static void error(mddev_t *mddev, mdk_rdev_t *rdev)
         }
         clear_bit(In_sync, &rdev->flags);
         set_bit(Faulty, &rdev->flags);
-        mddev->sb_dirty = 1;
+        set_bit(MD_CHANGE_DEVS, &mddev->flags);
         printk(KERN_ALERT "raid10: Disk failure on %s, disabling device. \n"
                 "       Operation continuing on %d devices\n",
                 bdevname(rdev->bdev,b), conf->working_disks);