Re: 2.6.11-rc4 md loops on missing drives
flat view
From: Neil Brown <hidden>
Date: 2005-02-16 00:27:20
On Tuesday February 15, brad@wasp.net.au wrote:
G'day all, I'm not really sure how it's supposed to cope with losing more disks than planned, but filling the syslog with nastiness is not very polite.
Thanks for the bug report. There are actually a few problems relating to resync/recovery when an array (raid 5 or 6) has lost too many devices. This patch should fix them. NeilBrown ------------------------------------------------ Make raid5 and raid6 robust against failure during recovery. Two problems are fixed here. 1/ if the array is known to require a resync (parity update), but there are too many failed devices, the resync cannot complete but will be retried indefinitedly. 2/ if the array has two many failed drives to be usable and a spare is available, reconstruction will be attempted, but cannot work. This also is retried indefinitely. Signed-off-by: Neil Brown <redacted> ### Diffstat output ./drivers/md/md.c | 12 ++++++------ ./drivers/md/raid5.c | 13 +++++++++++++ ./drivers/md/raid6main.c | 12 ++++++++++++ 3 files changed, 31 insertions(+), 6 deletions(-) diff ./drivers/md/md.c~current~ ./drivers/md/md.c
--- ./drivers/md/md.c~current~ 2005-02-16 11:25:25.000000000 +1100
+++ ./drivers/md/md.c 2005-02-16 11:25:31.000000000 +1100@@ -3655,18 +3655,18 @@ void md_check_recovery(mddev_t *mddev) /* no recovery is running. * remove any failed drives, then - * add spares if possible + * add spares if possible. + * Spare are also removed and re-added, to allow + * the personality to fail the re-add. */ - ITERATE_RDEV(mddev,rdev,rtmp) { + ITERATE_RDEV(mddev,rdev,rtmp) if (rdev->raid_disk >= 0 && - rdev->faulty && + (rdev->faulty || ! rdev->in_sync) && atomic_read(&rdev->nr_pending)==0) { if (mddev->pers->hot_remove_disk(mddev, rdev->raid_disk)==0) rdev->raid_disk = -1; } - if (!rdev->faulty && rdev->raid_disk >= 0 && !rdev->in_sync) - spares++; - } + if (mddev->degraded) { ITERATE_RDEV(mddev,rdev,rtmp) if (rdev->raid_disk < 0
diff ./drivers/md/raid5.c~current~ ./drivers/md/raid5.c
--- ./drivers/md/raid5.c~current~ 2005-02-16 11:25:25.000000000 +1100
+++ ./drivers/md/raid5.c 2005-02-16 11:25:31.000000000 +1100@@ -1491,6 +1491,15 @@ static int sync_request (mddev_t *mddev, unplug_slaves(mddev); return 0; } + /* if there is 1 or more failed drives and we are trying + * to resync, then assert that we are finished, because there is + * nothing we can do. + */ + if (mddev->degraded >= 1 && test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) { + int rv = (mddev->size << 1) - sector_nr; + md_done_sync(mddev, rv, 1); + return rv; + } x = sector_nr; chunk_offset = sector_div(x, sectors_per_chunk);
@@ -1882,6 +1891,10 @@ static int raid5_add_disk(mddev_t *mddev int disk; struct disk_info *p; + if (mddev->degraded > 1) + /* no point adding a device */ + return 0; + /* * find the disk ... */
diff ./drivers/md/raid6main.c~current~ ./drivers/md/raid6main.c
--- ./drivers/md/raid6main.c~current~ 2005-02-16 11:25:25.000000000 +1100
+++ ./drivers/md/raid6main.c 2005-02-16 11:25:31.000000000 +1100@@ -1650,6 +1650,15 @@ static int sync_request (mddev_t *mddev, unplug_slaves(mddev); return 0; } + /* if there are 2 or more failed drives and we are trying + * to resync, then assert that we are finished, because there is + * nothing we can do. + */ + if (mddev->degraded >= 2 && test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) { + int rv = (mddev->size << 1) - sector_nr; + md_done_sync(mddev, rv, 1); + return rv; + } x = sector_nr; chunk_offset = sector_div(x, sectors_per_chunk);
@@ -2048,6 +2057,9 @@ static int raid6_add_disk(mddev_t *mddev int disk; struct disk_info *p; + if (mddev->degraded > 2) + /* no point adding a device */ + return 0; /* * find the disk ... */