[PATCH 003 of 12] md: Delay starting md threads until array is completely setup.
From: NeilBrown <hidden>
Date: 2006-06-27 07:08:56
Also in:
lkml
When an array is started we start one or two threads (two if there is a reshape or recovery that needs to be completed). We currently start these *before* the array is completely set up and in particular before queue->queuedata is set. If the thread actually starts very quickly on another CPU, we can end up dereferencing queue->queuedata and oops. This patch also makes sure we don't try to start a recovery if a reshape is being restarted. ### Diffstat output ./drivers/md/md.c | 10 +++++----- ./drivers/md/raid5.c | 3 --- 2 files changed, 5 insertions(+), 8 deletions(-) diff .prev/drivers/md/md.c ./drivers/md/md.c
--- .prev/drivers/md/md.c 2006-06-27 12:17:32.000000000 +1000
+++ ./drivers/md/md.c 2006-06-27 12:17:32.000000000 +1000@@ -3100,8 +3100,7 @@ static int do_md_run(mddev_t * mddev) } set_bit(MD_RECOVERY_NEEDED, &mddev->recovery); - md_wakeup_thread(mddev->thread);
+ if (mddev->sb_dirty) md_update_sb(mddev);
@@ -3121,7 +3120,7 @@ static int do_md_run(mddev_t * mddev) * start recovery here. If we leave it to md_check_recovery, * it will remove the drives and not do the right thing */ - if (mddev->degraded) { + if (mddev->degraded && !mddev->sync_thread) { struct list_head *rtmp; int spares = 0; ITERATE_RDEV(mddev,rdev,rtmp)
@@ -3142,10 +3141,11 @@ static int do_md_run(mddev_t * mddev) mdname(mddev)); /* leave the spares where they are, it shouldn't hurt */ mddev->recovery = 0; - } else - md_wakeup_thread(mddev->sync_thread); + } } } + md_wakeup_thread(mddev->thread); + md_wakeup_thread(mddev->sync_thread); /* possibly kick off a reshape */ mddev->changed = 1; md_new_event(mddev);
diff .prev/drivers/md/raid5.c ./drivers/md/raid5.c
--- .prev/drivers/md/raid5.c 2006-06-27 12:16:41.000000000 +1000
+++ ./drivers/md/raid5.c 2006-06-27 12:17:32.000000000 +1000@@ -3248,9 +3248,6 @@ static int run(mddev_t *mddev) set_bit(MD_RECOVERY_RUNNING, &mddev->recovery); mddev->sync_thread = md_register_thread(md_do_sync, mddev, "%s_reshape"); - /* FIXME if md_register_thread fails?? */ - md_wakeup_thread(mddev->sync_thread); - } /* read-ahead size must cover two whole stripes, which is