From 5bf295975416f8e97117bbbcfb0191c00bc3e2b4 Mon Sep 17 00:00:00 2001 From: NeilBrown Date: Thu, 7 May 2009 12:50:57 +1000 Subject: [PATCH] md: remove ability to explicit set an inactive array to 'clean'. Being able to write 'clean' to an 'array_state' of an inactive array to activate it in 'clean' mode is both unnecessary and inconvenient. It is unnecessary because the same can be achieved by writing 'active'. This activates and array, but it still remains 'clean' until the first write. It is inconvenient because writing 'clean' is more often used to cause an 'active' array to revert to 'clean' mode (thus blocking any writes until a 'write-pending' is promoted to 'active'). Allowing 'clean' to both activate an array and mark an active array as clean can lead to races: One program writes 'clean' to mark the active array as clean at the same time as another program writes 'inactive' to deactivate (stop) and active array. Depending on which writes first, the array could be deactivated and immediately reactivated which isn't what was desired. So just disable the use of 'clean' to activate an array. This avoids a race that can be triggered with mdadm-3.0 and external metadata, so it suitable for -stable. Reported-by: Rafal Marszewski Acked-by: Dan Williams Cc: Signed-off-by: NeilBrown --- drivers/md/md.c | 7 ++----- 1 file changed, 2 insertions(+), 5 deletions(-) diff --git a/drivers/md/md.c b/drivers/md/md.c index 8350bde60d1bd..1dd723d318826 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -3066,11 +3066,8 @@ array_state_store(mddev_t *mddev, const char *buf, size_t len) } else err = -EBUSY; spin_unlock_irq(&mddev->write_lock); - } else { - mddev->ro = 0; - mddev->recovery_cp = MaxSector; - err = do_md_run(mddev); - } + } else + err = -EINVAL; break; case active: if (mddev->pers) {