[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, 2 deletions

diff --git a/drivers/md/multipath.c b/drivers/md/multipath.c
index 1cc9de44ce86..e4f168d063db 100644
--- a/drivers/md/multipath.c
+++ b/drivers/md/multipath.c
@@ -253,7 +253,7 @@ static void multipath_error (mddev_t *mddev, mdk_rdev_t *rdev)
                         char b[BDEVNAME_SIZE];
                         clear_bit(In_sync, &rdev->flags);
                         set_bit(Faulty, &rdev->flags);
-                        mddev->sb_dirty = 1;
+                        set_bit(MD_CHANGE_DEVS, &mddev->flags);
                         conf->working_disks--;
                         printk(KERN_ALERT "multipath: IO failure on %s,"
                                 " disabling IO path. \n Operation continuing"
@@ -470,7 +470,6 @@ static int multipath_run (mddev_t *mddev)
         }
 
         conf->raid_disks = mddev->raid_disks;
-        mddev->sb_dirty = 1;
         conf->mddev = mddev;
         spin_lock_init(&conf->device_lock);
         INIT_LIST_HEAD(&conf->retry_list);