From dabc4ec6ba72418ebca6bf1884f344bba40c8709 Mon Sep 17 00:00:00 2001
From: "shli@kernel.org" <shli@kernel.org>
Date: Mon, 15 Dec 2014 12:57:04 +1100
Subject: raid5: handle expansion/resync case with stripe batching

expansion/resync can grab a stripe when the stripe is in batch list. Since all
stripes in batch list must be in the same state, we can't allow some stripes
run into expansion/resync. So we delay expansion/resync for stripe in batch
list.

Signed-off-by: Shaohua Li <shli@fusionio.com>
Signed-off-by: NeilBrown <neilb@suse.de>

diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 54f3cb3..3ae097d 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -3440,8 +3440,10 @@ unhash:
 				      struct stripe_head, batch_list);
 		list_del_init(&sh->batch_list);
 
-		sh->state = head_sh->state & (~((1 << STRIPE_ACTIVE) |
-			(1 << STRIPE_PREREAD_ACTIVE)));
+		set_mask_bits(&sh->state, ~STRIPE_EXPAND_SYNC_FLAG,
+			      head_sh->state & ~((1 << STRIPE_ACTIVE) |
+						 (1 << STRIPE_PREREAD_ACTIVE) |
+						 STRIPE_EXPAND_SYNC_FLAG));
 		sh->check_state = head_sh->check_state;
 		sh->reconstruct_state = head_sh->reconstruct_state;
 		for (i = 0; i < sh->disks; i++) {
@@ -3453,6 +3455,8 @@ unhash:
 		spin_lock_irq(&sh->stripe_lock);
 		sh->batch_head = NULL;
 		spin_unlock_irq(&sh->stripe_lock);
+		if (sh->state & STRIPE_EXPAND_SYNC_FLAG)
+			set_bit(STRIPE_HANDLE, &sh->state);
 		release_stripe(sh);
 	}
 
@@ -3460,6 +3464,8 @@ unhash:
 	head_sh->batch_head = NULL;
 	spin_unlock_irq(&head_sh->stripe_lock);
 	wake_up_nr(&conf->wait_for_overlap, wakeup_nr);
+	if (head_sh->state & STRIPE_EXPAND_SYNC_FLAG)
+		set_bit(STRIPE_HANDLE, &head_sh->state);
 }
 
 static void handle_stripe_dirtying(struct r5conf *conf,
@@ -3927,8 +3933,8 @@ static void analyse_stripe(struct stripe_head *sh, struct stripe_head_state *s)
 
 	memset(s, 0, sizeof(*s));
 
-	s->expanding = test_bit(STRIPE_EXPAND_SOURCE, &sh->state);
-	s->expanded = test_bit(STRIPE_EXPAND_READY, &sh->state);
+	s->expanding = test_bit(STRIPE_EXPAND_SOURCE, &sh->state) && !sh->batch_head;
+	s->expanded = test_bit(STRIPE_EXPAND_READY, &sh->state) && !sh->batch_head;
 	s->failed_num[0] = -1;
 	s->failed_num[1] = -1;
 
@@ -4150,9 +4156,11 @@ static void check_break_stripe_batch_list(struct stripe_head *sh)
 					struct stripe_head, batch_list);
 		list_del_init(&sh->batch_list);
 
-		sh->state = head_sh->state & ~((1 << STRIPE_ACTIVE) |
-					       (1 << STRIPE_PREREAD_ACTIVE) |
-					       (1 << STRIPE_DEGRADED));
+		set_mask_bits(&sh->state, ~STRIPE_EXPAND_SYNC_FLAG,
+			      head_sh->state & ~((1 << STRIPE_ACTIVE) |
+						 (1 << STRIPE_PREREAD_ACTIVE) |
+						 (1 << STRIPE_DEGRADED) |
+						 STRIPE_EXPAND_SYNC_FLAG));
 		sh->check_state = head_sh->check_state;
 		sh->reconstruct_state = head_sh->reconstruct_state;
 		for (i = 0; i < sh->disks; i++)
@@ -4194,7 +4202,7 @@ static void handle_stripe(struct stripe_head *sh)
 
 	check_break_stripe_batch_list(sh);
 
-	if (test_bit(STRIPE_SYNC_REQUESTED, &sh->state)) {
+	if (test_bit(STRIPE_SYNC_REQUESTED, &sh->state) && !sh->batch_head) {
 		spin_lock(&sh->stripe_lock);
 		/* Cannot process 'sync' concurrently with 'discard' */
 		if (!test_bit(STRIPE_DISCARD, &sh->state) &&
diff --git a/drivers/md/raid5.h b/drivers/md/raid5.h
index cf3562e..ee65ed8 100644
--- a/drivers/md/raid5.h
+++ b/drivers/md/raid5.h
@@ -339,6 +339,11 @@ enum {
 	STRIPE_BATCH_ERR,
 };
 
+#define STRIPE_EXPAND_SYNC_FLAG \
+	((1 << STRIPE_EXPAND_SOURCE) |\
+	(1 << STRIPE_EXPAND_READY) |\
+	(1 << STRIPE_EXPANDING) |\
+	(1 << STRIPE_SYNC_REQUESTED))
 /*
  * Operation request flags
  */
-- 
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