From: NeilBrown Date: Thu, 7 May 2009 02:48:10 +0000 (+1000) Subject: md/raid10: don't clear bitmap during recovery if array will still be degraded. X-Git-Tag: v2.6.29.4~47 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=0861795f956793edd5cb4f8316b1c14f3dd4470a;p=thirdparty%2Fkernel%2Fstable.git md/raid10: don't clear bitmap during recovery if array will still be degraded. commit 18055569127253755d01733f6ecc004ed02f88d0 upstream. 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 Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c index 7301631abe045..d8495337dddf4 100644 --- a/drivers/md/raid10.c +++ b/drivers/md/raid10.c @@ -1807,17 +1807,17 @@ 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);