From 1217e1d1999ed6c9c1e1b1acae0a74ab70464ae2 Mon Sep 17 00:00:00 2001 From: NeilBrown Date: Fri, 28 Oct 2016 15:59:41 +1100 Subject: [PATCH] md: be careful not lot leak internal curr_resync value into metadata. -- (all) mddev->curr_resync usually records where the current resync is up to, but during the starting phase it has some "magic" values. 1 - means that the array is trying to start a resync, but has yielded to another array which shares physical devices, and also needs to start a resync 2 - means the array is trying to start resync, but has found another array which shares physical devices and has already started resync. 3 - means that resync has commensed, but it is possible that nothing has actually been resynced yet. It is important that this value not be visible to user-space and particularly that it doesn't get written to the metadata, as the resync or recovery checkpoint. In part, this is because it may be slightly higher than the correct value, though this is very rare. In part, because it is not a multiple of 4K, and some devices only support 4K aligned accesses. There are two places where this value is propagates into either ->curr_resync_completed or ->recovery_cp or ->recovery_offset. These currently avoid the propagation of values 1 and 3, but will allow 3 to leak through. Change them to only propagate the value if it is > 3. As this can cause an array to fail, the patch is suitable for -stable. Cc: stable@vger.kernel.org (v3.7+) Reported-by: Viswesh Signed-off-by: NeilBrown Signed-off-by: Shaohua Li --- drivers/md/md.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/md/md.c b/drivers/md/md.c index 25b57a5..2089d46 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -8144,14 +8144,14 @@ void md_do_sync(struct md_thread *thread) if (!test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery) && !test_bit(MD_RECOVERY_INTR, &mddev->recovery) && - mddev->curr_resync > 2) { + mddev->curr_resync > 3) { mddev->curr_resync_completed = mddev->curr_resync; sysfs_notify(&mddev->kobj, NULL, "sync_completed"); } mddev->pers->sync_request(mddev, max_sectors, &skipped); if (!test_bit(MD_RECOVERY_CHECK, &mddev->recovery) && - mddev->curr_resync > 2) { + mddev->curr_resync > 3) { if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) { if (test_bit(MD_RECOVERY_INTR, &mddev->recovery)) { if (mddev->curr_resync >= mddev->recovery_cp) { -- 2.7.4