From 18055569127253755d01733f6ecc004ed02f88d0 Mon Sep 17 00:00:00 2001 From: NeilBrown Date: Thu, 7 May 2009 12:48:10 +1000 Subject: [PATCH] md/raid10: don't clear bitmap during recovery if array will still be degraded. If we have a raid10 with multiple missing devices, and we recover just one of these to a spare, then we risk (depending on the bitmap and array chunk size) clearing bits of the bitmap for which recovery isn't complete (because a device is still missing). This can lead to a subsequent "re-add" being recovered without any IO happening, which would result in loss of data. This patch takes the safe approach of not clearing bitmap bits if the array will still be degraded. This patch is suitable for all active -stable kernels. Cc: stable@kernel.org Signed-off-by: NeilBrown --- drivers/md/raid10.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c index 81a54f17417e..499620afb44b 100644 --- a/drivers/md/raid10.c +++ b/drivers/md/raid10.c @@ -1809,17 +1809,17 @@ static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, i r10_bio->sector = sect; raid10_find_phys(conf, r10_bio); - /* Need to check if this section will still be + + /* Need to check if the array will still be * degraded */ - for (j=0; jcopies;j++) { - int d = r10_bio->devs[j].devnum; - if (conf->mirrors[d].rdev == NULL || - test_bit(Faulty, &conf->mirrors[d].rdev->flags)) { + for (j=0; jraid_disks; j++) + if (conf->mirrors[j].rdev == NULL || + test_bit(Faulty, &conf->mirrors[j].rdev->flags)) { still_degraded = 1; break; } - } + must_sync = bitmap_start_sync(mddev->bitmap, sect, &sync_blocks, still_degraded); -- 2.20.1