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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Guoqing Jiang <gqjiang@suse.com>,
        NeilBrown <neilb@suse.com>, Shaohua Li <shli@fb.com>,
        Sasha Levin <alexander.levin@microsoft.com>
Subject: [PATCH 4.4 011/113] md-cluster: clear another nodes suspend_area after the copy is finished
Date:   Mon,  8 Oct 2018 20:30:12 +0200
Message-Id: <20181008175531.394633401@linuxfoundation.org>
In-Reply-To: <20181008175530.864641368@linuxfoundation.org>
References: <20181008175530.864641368@linuxfoundation.org>
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4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Guoqing Jiang <gqjiang@suse.com>

[ Upstream commit 010228e4a932ca1e8365e3b58c8e1e44c16ff793 ]

When one node leaves cluster or stops the resyncing
(resync or recovery) array, then other nodes need to
call recover_bitmaps to continue the unfinished task.

But we need to clear suspend_area later after other
nodes copy the resync information to their bitmap
(by call bitmap_copy_from_slot). Otherwise, all nodes
could write to the suspend_area even the suspend_area
is not handled by any node, because area_resyncing
returns 0 at the beginning of raid1_write_request.
Which means one node could write suspend_area while
another node is resyncing the same area, then data
could be inconsistent.

So let's clear suspend_area later to avoid above issue
with the protection of bm lock. Also it is straightforward
to clear suspend_area after nodes have copied the resync
info to bitmap.

Signed-off-by: Guoqing Jiang <gqjiang@suse.com>
Reviewed-by: NeilBrown <neilb@suse.com>
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/md/md-cluster.c |   19 ++++++++++---------
 1 file changed, 10 insertions(+), 9 deletions(-)

--- a/drivers/md/md-cluster.c
+++ b/drivers/md/md-cluster.c
@@ -239,15 +239,6 @@ static void recover_bitmaps(struct md_th
 	while (cinfo->recovery_map) {
 		slot = fls64((u64)cinfo->recovery_map) - 1;
 
-		/* Clear suspend_area associated with the bitmap */
-		spin_lock_irq(&cinfo->suspend_lock);
-		list_for_each_entry_safe(s, tmp, &cinfo->suspend_list, list)
-			if (slot == s->slot) {
-				list_del(&s->list);
-				kfree(s);
-			}
-		spin_unlock_irq(&cinfo->suspend_lock);
-
 		snprintf(str, 64, "bitmap%04d", slot);
 		bm_lockres = lockres_init(mddev, str, NULL, 1);
 		if (!bm_lockres) {
@@ -266,6 +257,16 @@ static void recover_bitmaps(struct md_th
 			pr_err("md-cluster: Could not copy data from bitmap %d\n", slot);
 			goto dlm_unlock;
 		}
+
+		/* Clear suspend_area associated with the bitmap */
+		spin_lock_irq(&cinfo->suspend_lock);
+		list_for_each_entry_safe(s, tmp, &cinfo->suspend_list, list)
+			if (slot == s->slot) {
+				list_del(&s->list);
+				kfree(s);
+			}
+		spin_unlock_irq(&cinfo->suspend_lock);
+
 		if (hi > 0) {
 			/* TODO:Wait for current resync to get over */
 			set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);