1/ ops_complete_biofill tried to avoid calling handle_stripe since all the
state necessary to return read completions is available. However the
process of determining whether more read requests are pending requires
locking the stripe (to block add_stripe_bio from updating dev->toead).
ops_complete_biofill can run in tasklet context, so rather than upgrading
all the stripe locks from spin_lock to spin_lock_bh this patch just
unconditionally reschedules handle_stripe after completing the read
request.
2/ ops_complete_biofill needlessly qualified processing R5_Wantfill with
dev->toread. The result being that the 'biofill' pending bit is cleared
before handling the pending read-completions on dev->read. R5_Wantfill can
be unconditionally handled because the 'biofill' pending bit prevents new
R5_Wantfill requests from being seen by ops_run_biofill and
ops_complete_biofill.
Found-by: Yuri Tikhonov <yur@emcraft.com>
[neilb@suse.de: simpler fix for bug 1 than moving code]
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
struct stripe_head *sh = stripe_head_ref;
struct bio *return_bi = NULL;
raid5_conf_t *conf = sh->raid_conf;
struct stripe_head *sh = stripe_head_ref;
struct bio *return_bi = NULL;
raid5_conf_t *conf = sh->raid_conf;
- int i, more_to_read = 0;
pr_debug("%s: stripe %llu\n", __FUNCTION__,
(unsigned long long)sh->sector);
pr_debug("%s: stripe %llu\n", __FUNCTION__,
(unsigned long long)sh->sector);
/* clear completed biofills */
for (i = sh->disks; i--; ) {
struct r5dev *dev = &sh->dev[i];
/* clear completed biofills */
for (i = sh->disks; i--; ) {
struct r5dev *dev = &sh->dev[i];
- /* check if this stripe has new incoming reads */
- if (dev->toread)
- more_to_read++;
/* acknowledge completion of a biofill operation */
/* acknowledge completion of a biofill operation */
- /* and check if we need to reply to a read request
- */
- if (test_bit(R5_Wantfill, &dev->flags) && !dev->toread) {
+ /* and check if we need to reply to a read request,
+ * new R5_Wantfill requests are held off until
+ * !test_bit(STRIPE_OP_BIOFILL, &sh->ops.pending)
+ */
+ if (test_and_clear_bit(R5_Wantfill, &dev->flags)) {
- clear_bit(R5_Wantfill, &dev->flags);
/* The access to dev->read is outside of the
* spin_lock_irq(&conf->device_lock), but is protected
/* The access to dev->read is outside of the
* spin_lock_irq(&conf->device_lock), but is protected
- if (more_to_read)
- set_bit(STRIPE_HANDLE, &sh->state);
+ set_bit(STRIPE_HANDLE, &sh->state);