@@ -4235,8 +4235,7 @@ action_store(struct mddev *mddev, const char *page, size_t len)
}
mddev_unlock(mddev);
}
- } else if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) ||
- test_bit(MD_RECOVERY_NEEDED, &mddev->recovery))
+ } else if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
return -EBUSY;
else if (cmd_match(page, "resync"))
clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
@@ -4249,8 +4248,12 @@ action_store(struct mddev *mddev, const char *page, size_t len)
return -EINVAL;
err = mddev_lock(mddev);
if (!err) {
- clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
- err = mddev->pers->start_reshape(mddev);
+ if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
+ err = -EBUSY;
+ else {
+ clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
+ err = mddev->pers->start_reshape(mddev);
+ }
mddev_unlock(mddev);
}
if (err)
This is a note to let you know that I have just added a patch titled md: remove check for MD_RECOVERY_NEEDED in action_store. to the linux-4.2.y-queue branch of the 4.2.y-ckt extended stable tree which can be found at: http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-4.2.y-queue This patch is scheduled to be released in version 4.2.8-ckt2. If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 4.2.y-ckt tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Kamal ---8<------------------------------------------------------------ From 00bef3ea5bb33428b0e4e7d18ce7acf43dec38b7 Mon Sep 17 00:00:00 2001 From: NeilBrown <neilb@suse.com> Date: Mon, 21 Dec 2015 11:01:21 +1100 Subject: md: remove check for MD_RECOVERY_NEEDED in action_store. commit 312045eef985b61d74c28047ecd8eca6719d9516 upstream. md currently doesn't allow a 'sync_action' such as 'reshape' to be set while MD_RECOVERY_NEEDED is set. This s a problem, particularly since commit 738a273806ee as that can cause ->check_shape to call mddev_resume() which sets MD_RECOVERY_NEEDED. So by the time we come to start 'reshape' it is very likely that MD_RECOVERY_NEEDED is still set. Testing for this flag is not really needed and is in any case very racy as it can be set at any moment - asynchronously. Any race between setting a sync_action and setting MD_RECOVERY_NEEDED must already be handled properly in some locked code, probably md_check_recovery(), so remove the test here. The test on MD_RECOVERY_RUNNING is also racy in the 'reshape' case so we should test it again after getting mddev_lock(). As this fixes a race and a regression which can cause 'reshape' to fail, it is suitable for -stable kernels since 4.1 Reported-by: Xiao Ni <xni@redhat.com> Fixes: 738a273806ee ("md/raid5: fix allocation of 'scribble' array.") Signed-off-by: NeilBrown <neilb@suse.com> Signed-off-by: Kamal Mostafa <kamal@canonical.com> --- drivers/md/md.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) -- 1.9.1