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md: fix 'safemode' handling for external metadata.

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'safemode' relates to marking an array as 'clean' if there has been no write
traffic for a while (a couple of seconds), to reduce the chance of the array
being found dirty on reboot.

->safemode is set to '1' when there have been no write for a while, and it
gets set to '0' when the superblock is updates with the 'clean' flag set.

This requires a few fixes for 'external' metadata:
 - When an array is set to 'clean' via sysfs, 'safemode' must be cleared.
 - when we write to an array that has 'safemode' set (there must have been
        some delay in updating the metadata), we need to clear safemode.
 - Don't try to update external metadata in md_check_recovery for safemode
        transitions - it won't work.

Also, don't try to support "immediate safe mode" (safemode==2) for external
metadata, it cannot really work (the safemode timeout can be set very low if
this is really needed).

Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
NeilBrown 2008-04-30 00:52:30 -07:00 committed by Linus Torvalds
parent d897dbf914
commit 31a59e3425
1 changed files with 19 additions and 11 deletions
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30
drivers/md/md.c
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@ -2615,6 +2615,8 @@ array_state_store(mddev_t *mddev, const char *buf, size_t len)
if (atomic_read(&mddev->writes_pending) == 0) {
if (mddev->in_sync == 0) {
mddev->in_sync = 1;
if (mddev->safemode == 1)
mddev->safemode = 0;
if (mddev->persistent)
set_bit(MD_CHANGE_CLEAN,
&mddev->flags);
@ -5392,6 +5394,8 @@ void md_write_start(mddev_t *mddev, struct bio *bi)
md_wakeup_thread(mddev->sync_thread);
}
atomic_inc(&mddev->writes_pending);
if (mddev->safemode == 1)
mddev->safemode = 0;
if (mddev->in_sync) {
spin_lock_irq(&mddev->write_lock);
if (mddev->in_sync) {
@ -5816,7 +5820,7 @@ void md_check_recovery(mddev_t *mddev)
return;
if (signal_pending(current)) {
if (mddev->pers->sync_request) {
if (mddev->pers->sync_request && !mddev->external) {
printk(KERN_INFO "md: %s in immediate safe mode\n",
mdname(mddev));
mddev->safemode = 2;
@ -5828,7 +5832,7 @@ void md_check_recovery(mddev_t *mddev)
(mddev->flags && !mddev->external) ||
test_bit(MD_RECOVERY_NEEDED, &mddev->recovery) ||
test_bit(MD_RECOVERY_DONE, &mddev->recovery) ||
(mddev->safemode == 1) ||
(mddev->external == 0 && mddev->safemode == 1) ||
(mddev->safemode == 2 && ! atomic_read(&mddev->writes_pending)
&& !mddev->in_sync && mddev->recovery_cp == MaxSector)
))
@ -5837,16 +5841,20 @@ void md_check_recovery(mddev_t *mddev)
if (mddev_trylock(mddev)) {
int spares = 0;
spin_lock_irq(&mddev->write_lock);
if (mddev->safemode && !atomic_read(&mddev->writes_pending) &&
!mddev->in_sync && mddev->recovery_cp == MaxSector) {
mddev->in_sync = 1;
if (mddev->persistent)
set_bit(MD_CHANGE_CLEAN, &mddev->flags);
if (!mddev->external) {
spin_lock_irq(&mddev->write_lock);
if (mddev->safemode &&
!atomic_read(&mddev->writes_pending) &&
!mddev->in_sync &&
mddev->recovery_cp == MaxSector) {
mddev->in_sync = 1;
if (mddev->persistent)
set_bit(MD_CHANGE_CLEAN, &mddev->flags);
}
if (mddev->safemode == 1)
mddev->safemode = 0;
spin_unlock_irq(&mddev->write_lock);
}
if (mddev->safemode == 1)
mddev->safemode = 0;
spin_unlock_irq(&mddev->write_lock);
if (mddev->flags)
md_update_sb(mddev, 0);