[PATCH v6 1/2] md/raid10: Do not add spare disk when recovery fail

[linan666]

From: Li Nan <linan122@xxxxxxxxxx>

In raid10_sync_request(), if data cannot be read from any disk for
recovery, it will go to 'giveup' and let 'chunks_skipped' + 1. After
multiple 'giveup', when 'chunks_skipped >= geo.raid_disks', it will
return 'max_sector', indicating that the recovery has been completed.
However, the recovery is just aborted and the data remains inconsistent.

Fix it by setting mirror->recovery_disabled, which will prevent the spare
disk from being added to this mirror. The same issue also exists during
resync, it will be fixed afterwards.

Signed-off-by: Li Nan <linan122@xxxxxxxxxx>
---
 drivers/md/raid10.c | 20 ++++++++++++++++++--
 1 file changed, 18 insertions(+), 2 deletions(-)

diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index d93d8cb2b620..9fb55902e58a 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -3303,6 +3303,7 @@ static sector_t raid10_sync_request(struct mddev *mddev, sector_t sector_nr,
 	int chunks_skipped = 0;
 	sector_t chunk_mask = conf->geo.chunk_mask;
 	int page_idx = 0;
+	int error_disk = -1;
 
 	/*
 	 * Allow skipping a full rebuild for incremental assembly
@@ -3386,8 +3387,21 @@ static sector_t raid10_sync_request(struct mddev *mddev, sector_t sector_nr,
 		return reshape_request(mddev, sector_nr, skipped);
 
 	if (chunks_skipped >= conf->geo.raid_disks) {
-		/* if there has been nothing to do on any drive,
-		 * then there is nothing to do at all..
+		pr_err("md/raid10:%s: %s fail\n", mdname(mddev),
+			test_bit(MD_RECOVERY_SYNC, &mddev->recovery) ?  "resync" : "recovery");
+		if (error_disk >= 0 &&
+		    !test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
+			/*
+			 * recovery fail, set mirrors.recovery_disabled,
+			 * device shouldn't be added to there.
+			 */
+			conf->mirrors[error_disk].recovery_disabled =
+						mddev->recovery_disabled;
+			return 0;
+		}
+		/*
+		 * if there has been nothing to do on any drive,
+		 * then there is nothing to do at all.
 		 */
 		*skipped = 1;
 		return (max_sector - sector_nr) + sectors_skipped;
@@ -3638,6 +3652,8 @@ static sector_t raid10_sync_request(struct mddev *mddev, sector_t sector_nr,
 						       mdname(mddev));
 					mirror->recovery_disabled
 						= mddev->recovery_disabled;
+				} else {
+					error_disk = i;
 				}
 				put_buf(r10_bio);
 				if (rb2)
-- 
2.39.2