#include "raid0.h"
#include "bitmap.h"
+static bool devices_handle_discard_safely = false;
+module_param(devices_handle_discard_safely, bool, 0644);
+MODULE_PARM_DESC(devices_handle_discard_safely,
+ "Set to Y if all devices in each array reliably return zeroes on reads from discarded regions");
/*
* Stripe cache
*/
conf->slab_cache = sc;
conf->active_name = 1-conf->active_name;
- conf->pool_size = newsize;
+ if (!err)
+ conf->pool_size = newsize;
return err;
}
(s->failed >= 2 && fdev[1]->toread) ||
(sh->raid_conf->level <= 5 && s->failed && fdev[0]->towrite &&
!test_bit(R5_OVERWRITE, &fdev[0]->flags)) ||
- (sh->raid_conf->level == 6 && s->failed && s->to_write))) {
+ ((sh->raid_conf->level == 6 || sh->sector >= sh->raid_conf->mddev->recovery_cp)
+ && s->failed && s->to_write))) {
/* we would like to get this block, possibly by computing it,
* otherwise read it if the backing disk is insync
*/
* generate correct data from the parity.
*/
if (conf->max_degraded == 2 ||
- (recovery_cp < MaxSector && sh->sector >= recovery_cp)) {
+ (recovery_cp < MaxSector && sh->sector >= recovery_cp &&
+ s->failed == 0)) {
/* Calculate the real rcw later - for now make it
* look like rcw is cheaper
*/
mddev->queue->limits.discard_granularity = stripe;
/*
* unaligned part of discard request will be ignored, so can't
- * guarantee discard_zerors_data
+ * guarantee discard_zeroes_data
*/
mddev->queue->limits.discard_zeroes_data = 0;
!bdev_get_queue(rdev->bdev)->
limits.discard_zeroes_data)
discard_supported = false;
+ /* Unfortunately, discard_zeroes_data is not currently
+ * a guarantee - just a hint. So we only allow DISCARD
+ * if the sysadmin has confirmed that only safe devices
+ * are in use by setting a module parameter.
+ */
+ if (!devices_handle_discard_safely) {
+ if (discard_supported) {
+ pr_info("md/raid456: discard support disabled due to uncertainty.\n");
+ pr_info("Set raid456.devices_handle_discard_safely=Y to override.\n");
+ }
+ discard_supported = false;
+ }
}
if (discard_supported &&