md/raid5,6: common schedule_reconstruction for raid5/6

Extend schedule_reconstruction5 for reuse by the raid6 path.  Add
support for generating Q and BUG() if a request is made to perform
'prexor'.

Signed-off-by: Yuri Tikhonov <yur@emcraft.com>
Signed-off-by: Ilya Yanok <yanok@emcraft.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

1 files changed, 18 insertions, 6 deletions

diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index e68616ed3e78..a1245cf99957 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -2175,10 +2175,12 @@ static void compute_block_2(struct stripe_head *sh, int dd_idx1, int dd_idx2)
 }
 
 static void
-schedule_reconstruction5(struct stripe_head *sh, struct stripe_head_state *s,
+schedule_reconstruction(struct stripe_head *sh, struct stripe_head_state *s,
                          int rcw, int expand)
 {
         int i, pd_idx = sh->pd_idx, disks = sh->disks;
+        raid5_conf_t *conf = sh->raid_conf;
+        int level = conf->level;
 
         if (rcw) {
                 /* if we are not expanding this is a proper write request, and
@@ -2204,10 +2206,11 @@ schedule_reconstruction5(struct stripe_head *sh, struct stripe_head_state *s,
                                 s->locked++;
                         }
                 }
-                if (s->locked + 1 == disks)
+                if (s->locked + conf->max_degraded == disks)
                         if (!test_and_set_bit(STRIPE_FULL_WRITE, &sh->state))
-                                atomic_inc(&sh->raid_conf->pending_full_writes);
+                                atomic_inc(&conf->pending_full_writes);
         } else {
+                BUG_ON(level == 6);
                 BUG_ON(!(test_bit(R5_UPTODATE, &sh->dev[pd_idx].flags) ||
                         test_bit(R5_Wantcompute, &sh->dev[pd_idx].flags)));
 
@@ -2232,13 +2235,22 @@ schedule_reconstruction5(struct stripe_head *sh, struct stripe_head_state *s,
                 }
         }
 
-        /* keep the parity disk locked while asynchronous operations
+        /* keep the parity disk(s) locked while asynchronous operations
          * are in flight
          */
         set_bit(R5_LOCKED, &sh->dev[pd_idx].flags);
         clear_bit(R5_UPTODATE, &sh->dev[pd_idx].flags);
         s->locked++;
 
+        if (level == 6) {
+                int qd_idx = sh->qd_idx;
+                struct r5dev *dev = &sh->dev[qd_idx];
+
+                set_bit(R5_LOCKED, &dev->flags);
+                clear_bit(R5_UPTODATE, &dev->flags);
+                s->locked++;
+        }
+
         pr_debug("%s: stripe %llu locked: %d ops_request: %lx\n",
                 __func__, (unsigned long long)sh->sector,
                 s->locked, s->ops_request);
@@ -2704,7 +2716,7 @@ static void handle_stripe_dirtying5(raid5_conf_t *conf,
         if ((s->req_compute || !test_bit(STRIPE_COMPUTE_RUN, &sh->state)) &&
             (s->locked == 0 && (rcw == 0 || rmw == 0) &&
             !test_bit(STRIPE_BIT_DELAY, &sh->state)))
-                schedule_reconstruction5(sh, s, rcw == 0, 0);
+                schedule_reconstruction(sh, s, rcw == 0, 0);
 }
 
 static void handle_stripe_dirtying6(raid5_conf_t *conf,
@@ -3309,7 +3321,7 @@ static bool handle_stripe5(struct stripe_head *sh)
                 /* Need to write out all blocks after computing parity */
                 sh->disks = conf->raid_disks;
                 stripe_set_idx(sh->sector, conf, 0, sh);
-                schedule_reconstruction5(sh, &s, 1, 1);
+                schedule_reconstruction(sh, &s, 1, 1);
         } else if (s.expanded && !sh->reconstruct_state && s.locked == 0) {
                 clear_bit(STRIPE_EXPAND_READY, &sh->state);
                 atomic_dec(&conf->reshape_stripes);