[PATCH 005 of 6] md: Restart a (raid5) reshape that has been aborted due to a read/write error.

From: NeilBrown
Date: Tue Feb 20 2007 - 01:37:54 EST



An error always aborts any resync/recovery/reshape on the understanding
that it will immediately be restarted if that still makes sense.
However a reshape currently doesn't get restarted. With this patch
it does.
To avoid restarting when it is not possible to do work, we call
into the personality to check that a reshape is ok, and strengthen
raid5_check_reshape to fail if there are too many failed devices.

We also break some code out into a separate function: remove_and_add_spares
as the indent level for that code was getting crazy.

Signed-off-by: Neil Brown <neilb@xxxxxxx>

### Diffstat output
./drivers/md/md.c | 74 +++++++++++++++++++++++++++++++--------------------
./drivers/md/raid5.c | 2 +
2 files changed, 47 insertions(+), 29 deletions(-)

diff .prev/drivers/md/md.c ./drivers/md/md.c
--- .prev/drivers/md/md.c 2007-02-20 17:13:08.000000000 +1100
+++ ./drivers/md/md.c 2007-02-20 17:14:35.000000000 +1100
@@ -5357,6 +5357,44 @@ void md_do_sync(mddev_t *mddev)
EXPORT_SYMBOL_GPL(md_do_sync);


+static int remove_and_add_spares(mddev_t *mddev)
+{
+ mdk_rdev_t *rdev;
+ struct list_head *rtmp;
+ int spares = 0;
+
+ ITERATE_RDEV(mddev,rdev,rtmp)
+ if (rdev->raid_disk >= 0 &&
+ (test_bit(Faulty, &rdev->flags) ||
+ ! test_bit(In_sync, &rdev->flags)) &&
+ atomic_read(&rdev->nr_pending)==0) {
+ if (mddev->pers->hot_remove_disk(
+ mddev, rdev->raid_disk)==0) {
+ char nm[20];
+ sprintf(nm,"rd%d", rdev->raid_disk);
+ sysfs_remove_link(&mddev->kobj, nm);
+ rdev->raid_disk = -1;
+ }
+ }
+
+ if (mddev->degraded) {
+ ITERATE_RDEV(mddev,rdev,rtmp)
+ if (rdev->raid_disk < 0
+ && !test_bit(Faulty, &rdev->flags)) {
+ rdev->recovery_offset = 0;
+ if (mddev->pers->hot_add_disk(mddev,rdev)) {
+ char nm[20];
+ sprintf(nm, "rd%d", rdev->raid_disk);
+ sysfs_create_link(&mddev->kobj,
+ &rdev->kobj, nm);
+ spares++;
+ md_new_event(mddev);
+ } else
+ break;
+ }
+ }
+ return spares;
+}
/*
* This routine is regularly called by all per-raid-array threads to
* deal with generic issues like resync and super-block update.
@@ -5411,7 +5449,7 @@ void md_check_recovery(mddev_t *mddev)
return;

if (mddev_trylock(mddev)) {
- int spares =0;
+ int spares = 0;

spin_lock_irq(&mddev->write_lock);
if (mddev->safemode && !atomic_read(&mddev->writes_pending) &&
@@ -5474,35 +5512,13 @@ void md_check_recovery(mddev_t *mddev)
* Spare are also removed and re-added, to allow
* the personality to fail the re-add.
*/
- ITERATE_RDEV(mddev,rdev,rtmp)
- if (rdev->raid_disk >= 0 &&
- (test_bit(Faulty, &rdev->flags) || ! test_bit(In_sync, &rdev->flags)) &&
- atomic_read(&rdev->nr_pending)==0) {
- if (mddev->pers->hot_remove_disk(mddev, rdev->raid_disk)==0) {
- char nm[20];
- sprintf(nm,"rd%d", rdev->raid_disk);
- sysfs_remove_link(&mddev->kobj, nm);
- rdev->raid_disk = -1;
- }
- }
-
- if (mddev->degraded) {
- ITERATE_RDEV(mddev,rdev,rtmp)
- if (rdev->raid_disk < 0
- && !test_bit(Faulty, &rdev->flags)) {
- rdev->recovery_offset = 0;
- if (mddev->pers->hot_add_disk(mddev,rdev)) {
- char nm[20];
- sprintf(nm, "rd%d", rdev->raid_disk);
- sysfs_create_link(&mddev->kobj, &rdev->kobj, nm);
- spares++;
- md_new_event(mddev);
- } else
- break;
- }
- }

- if (spares) {
+ if (mddev->reshape_position != MaxSector) {
+ if (mddev->pers->check_reshape(mddev) != 0)
+ /* Cannot proceed */
+ goto unlock;
+ set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
+ } else if ((spares = remove_and_add_spares(mddev))) {
clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
} else if (mddev->recovery_cp < MaxSector) {

diff .prev/drivers/md/raid5.c ./drivers/md/raid5.c
--- .prev/drivers/md/raid5.c 2007-02-20 17:10:06.000000000 +1100
+++ ./drivers/md/raid5.c 2007-02-20 17:14:35.000000000 +1100
@@ -3814,6 +3814,8 @@ static int raid5_check_reshape(mddev_t *
if (err)
return err;

+ if (mddev->degraded > conf->max_degraded)
+ return -EINVAL;
/* looks like we might be able to manage this */
return 0;
}
-
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