[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>
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 3af6f1f..8b08043 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -1587,7 +1587,7 @@
}
}
-void md_update_sb(mddev_t * mddev)
+static void md_update_sb(mddev_t * mddev, int force_change)
{
int err;
struct list_head *tmp;
@@ -1598,7 +1598,18 @@
repeat:
spin_lock_irq(&mddev->write_lock);
- if (mddev->degraded && mddev->sb_dirty == 3)
+ set_bit(MD_CHANGE_PENDING, &mddev->flags);
+ if (test_and_clear_bit(MD_CHANGE_DEVS, &mddev->flags))
+ force_change = 1;
+ if (test_and_clear_bit(MD_CHANGE_CLEAN, &mddev->flags))
+ /* just a clean<-> dirty transition, possibly leave spares alone,
+ * though if events isn't the right even/odd, we will have to do
+ * spares after all
+ */
+ nospares = 1;
+ if (force_change)
+ nospares = 0;
+ if (mddev->degraded)
/* If the array is degraded, then skipping spares is both
* dangerous and fairly pointless.
* Dangerous because a device that was removed from the array
@@ -1608,20 +1619,14 @@
* then a recovery will happen and soon that array won't
* be degraded any more and the spare can go back to sleep then.
*/
- mddev->sb_dirty = 1;
+ nospares = 0;
sync_req = mddev->in_sync;
mddev->utime = get_seconds();
- if (mddev->sb_dirty == 3)
- /* just a clean<-> dirty transition, possibly leave spares alone,
- * though if events isn't the right even/odd, we will have to do
- * spares after all
- */
- nospares = 1;
/* If this is just a dirty<->clean transition, and the array is clean
* and 'events' is odd, we can roll back to the previous clean state */
- if (mddev->sb_dirty == 3
+ if (nospares
&& (mddev->in_sync && mddev->recovery_cp == MaxSector)
&& (mddev->events & 1))
mddev->events--;
@@ -1652,7 +1657,6 @@
MD_BUG();
mddev->events --;
}
- mddev->sb_dirty = 2;
sync_sbs(mddev, nospares);
/*
@@ -1660,7 +1664,7 @@
* nonpersistent superblocks
*/
if (!mddev->persistent) {
- mddev->sb_dirty = 0;
+ clear_bit(MD_CHANGE_PENDING, &mddev->flags);
spin_unlock_irq(&mddev->write_lock);
wake_up(&mddev->sb_wait);
return;
@@ -1697,20 +1701,20 @@
break;
}
md_super_wait(mddev);
- /* if there was a failure, sb_dirty was set to 1, and we re-write super */
+ /* if there was a failure, MD_CHANGE_DEVS was set, and we re-write super */
spin_lock_irq(&mddev->write_lock);
- if (mddev->in_sync != sync_req|| mddev->sb_dirty == 1) {
+ if (mddev->in_sync != sync_req ||
+ test_bit(MD_CHANGE_DEVS, &mddev->flags)) {
/* have to write it out again */
spin_unlock_irq(&mddev->write_lock);
goto repeat;
}
- mddev->sb_dirty = 0;
+ clear_bit(MD_CHANGE_PENDING, &mddev->flags);
spin_unlock_irq(&mddev->write_lock);
wake_up(&mddev->sb_wait);
}
-EXPORT_SYMBOL_GPL(md_update_sb);
/* words written to sysfs files may, or my not, be \n terminated.
* We want to accept with case. For this we use cmd_match.
@@ -1783,7 +1787,7 @@
else {
mddev_t *mddev = rdev->mddev;
kick_rdev_from_array(rdev);
- md_update_sb(mddev);
+ md_update_sb(mddev, 1);
md_new_event(mddev);
err = 0;
}
@@ -2426,7 +2430,7 @@
spin_lock_irq(&mddev->write_lock);
if (atomic_read(&mddev->writes_pending) == 0) {
mddev->in_sync = 1;
- mddev->sb_dirty = 1;
+ set_bit(MD_CHANGE_CLEAN, &mddev->flags);
}
spin_unlock_irq(&mddev->write_lock);
} else {
@@ -2438,7 +2442,7 @@
case active:
if (mddev->pers) {
restart_array(mddev);
- mddev->sb_dirty = 0;
+ clear_bit(MD_CHANGE_CLEAN, &mddev->flags);
wake_up(&mddev->sb_wait);
err = 0;
} else {
@@ -2543,7 +2547,7 @@
if (mddev->pers) {
err = update_size(mddev, size);
- md_update_sb(mddev);
+ md_update_sb(mddev, 1);
} else {
if (mddev->size == 0 ||
mddev->size > size)
@@ -3111,8 +3115,8 @@
set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
- if (mddev->sb_dirty)
- md_update_sb(mddev);
+ if (mddev->flags)
+ md_update_sb(mddev, 0);
set_capacity(disk, mddev->array_size<<1);
@@ -3275,10 +3279,10 @@
if (mddev->ro)
mddev->ro = 0;
}
- if (!mddev->in_sync || mddev->sb_dirty) {
+ if (!mddev->in_sync || mddev->flags) {
/* mark array as shutdown cleanly */
mddev->in_sync = 1;
- md_update_sb(mddev);
+ md_update_sb(mddev, 1);
}
if (mode == 1)
set_disk_ro(disk, 1);
@@ -3747,7 +3751,7 @@
goto busy;
kick_rdev_from_array(rdev);
- md_update_sb(mddev);
+ md_update_sb(mddev, 1);
md_new_event(mddev);
return 0;
@@ -3824,7 +3828,7 @@
rdev->raid_disk = -1;
- md_update_sb(mddev);
+ md_update_sb(mddev, 1);
/*
* Kick recovery, maybe this spare has to be added to the
@@ -3955,7 +3959,8 @@
mddev->max_disks = MD_SB_DISKS;
- mddev->sb_dirty = 1;
+ mddev->flags = 0;
+ set_bit(MD_CHANGE_DEVS, &mddev->flags);
mddev->default_bitmap_offset = MD_SB_BYTES >> 9;
mddev->bitmap_offset = 0;
@@ -4124,7 +4129,7 @@
mddev->bitmap_offset = 0;
}
}
- md_update_sb(mddev);
+ md_update_sb(mddev, 1);
return rv;
}
@@ -4960,12 +4965,12 @@
spin_lock_irq(&mddev->write_lock);
if (mddev->in_sync) {
mddev->in_sync = 0;
- mddev->sb_dirty = 3;
+ set_bit(MD_CHANGE_CLEAN, &mddev->flags);
md_wakeup_thread(mddev->thread);
}
spin_unlock_irq(&mddev->write_lock);
}
- wait_event(mddev->sb_wait, mddev->sb_dirty==0);
+ wait_event(mddev->sb_wait, mddev->flags==0);
}
void md_write_end(mddev_t *mddev)
@@ -5235,7 +5240,6 @@
!test_bit(In_sync, &rdev->flags) &&
rdev->recovery_offset < mddev->curr_resync)
rdev->recovery_offset = mddev->curr_resync;
- mddev->sb_dirty = 1;
}
}
@@ -5292,7 +5296,7 @@
}
if ( ! (
- mddev->sb_dirty ||
+ mddev->flags ||
test_bit(MD_RECOVERY_NEEDED, &mddev->recovery) ||
test_bit(MD_RECOVERY_DONE, &mddev->recovery) ||
(mddev->safemode == 1) ||
@@ -5308,14 +5312,14 @@
if (mddev->safemode && !atomic_read(&mddev->writes_pending) &&
!mddev->in_sync && mddev->recovery_cp == MaxSector) {
mddev->in_sync = 1;
- mddev->sb_dirty = 3;
+ set_bit(MD_CHANGE_CLEAN, &mddev->flags);
}
if (mddev->safemode == 1)
mddev->safemode = 0;
spin_unlock_irq(&mddev->write_lock);
- if (mddev->sb_dirty)
- md_update_sb(mddev);
+ if (mddev->flags)
+ md_update_sb(mddev, 0);
if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) &&
@@ -5334,7 +5338,7 @@
/* activate any spares */
mddev->pers->spare_active(mddev);
}
- md_update_sb(mddev);
+ md_update_sb(mddev, 1);
/* if array is no-longer degraded, then any saved_raid_disk
* information must be scrapped