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authorNeilBrown <neilb@suse.com>2016-10-28 15:59:41 +1100
committerSasha Levin <alexander.levin@verizon.com>2016-11-23 23:09:03 -0500
commit919224dcf46262156e9c90dd4858a2097730d074 (patch)
tree273aad4e0d877e35447ca5b70a2d02c55b7c5586
parentdebebae7513631270b3051dac8e5e7a0e3bdfe89 (diff)
downloadlinux-linaro-stable-919224dcf46262156e9c90dd4858a2097730d074.tar.gz
md: be careful not lot leak internal curr_resync value into metadata. -- (all)
[ Upstream commit 1217e1d1999ed6c9c1e1b1acae0a74ab70464ae2 ] 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 <viswesh.vichu@gmail.com> Signed-off-by: NeilBrown <neilb@suse.com> Signed-off-by: Shaohua Li <shli@fb.com> Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
-rw-r--r--drivers/md/md.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 7987e87a1be0..a4b0b4e43b40 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -7473,7 +7473,7 @@ 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");
}
@@ -7481,7 +7481,7 @@ void md_do_sync(struct md_thread *thread)
mddev->pers->sync_request(mddev, max_sectors, &skipped, 1);
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) {