From c744a65c1e2d59acc54333ce80a5b0702a98010b Mon Sep 17 00:00:00 2001 From: NeilBrown Date: Mon, 19 Mar 2012 12:46:37 +1100 Subject: [PATCH] md: don't set md arrays to readonly on shutdown. It seems that with recent kernel, writeback can still be happening while shutdown is happening, and consequently data can be written after the md reboot notifier switches all arrays to read-only. This causes a BUG. So don't switch them to read-only - just mark them clean and set 'safemode' to '2' which mean that immediately after any write the array will be switch back to 'clean'. This could result in the shutdown happening when array is marked dirty, thus forcing a resync on reboot. However if you reboot without performing a "sync" first, you get to keep both halves. This is suitable for any stable kernel (though there might be some conflicts with obvious fixes in earlier kernels). Cc: stable@vger.kernel.org Signed-off-by: NeilBrown --- drivers/md/md.c | 37 +++++++++++++++---------------------- 1 file changed, 15 insertions(+), 22 deletions(-) diff --git a/drivers/md/md.c b/drivers/md/md.c index ce88755baf4a..115a6dd85837 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -8157,30 +8157,23 @@ static int md_notify_reboot(struct notifier_block *this, struct mddev *mddev; int need_delay = 0; - if ((code == SYS_DOWN) || (code == SYS_HALT) || (code == SYS_POWER_OFF)) { - - printk(KERN_INFO "md: stopping all md devices.\n"); - - for_each_mddev(mddev, tmp) { - if (mddev_trylock(mddev)) { - /* Force a switch to readonly even array - * appears to still be in use. Hence - * the '100'. - */ - md_set_readonly(mddev, 100); - mddev_unlock(mddev); - } - need_delay = 1; + for_each_mddev(mddev, tmp) { + if (mddev_trylock(mddev)) { + __md_stop_writes(mddev); + mddev->safemode = 2; + mddev_unlock(mddev); } - /* - * certain more exotic SCSI devices are known to be - * volatile wrt too early system reboots. While the - * right place to handle this issue is the given - * driver, we do want to have a safe RAID driver ... - */ - if (need_delay) - mdelay(1000*1); + need_delay = 1; } + /* + * certain more exotic SCSI devices are known to be + * volatile wrt too early system reboots. While the + * right place to handle this issue is the given + * driver, we do want to have a safe RAID driver ... + */ + if (need_delay) + mdelay(1000*1); + return NOTIFY_DONE; } -- 2.20.1