linux-kernel - [PATCH v3 12/15] md/raid5: Check all disks in a stripe

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Date:   Thu, 16 Jun 2022 13:19:42 -0600
From:   Logan Gunthorpe <logang@...tatee.com>
To:     linux-kernel@...r.kernel.org, linux-raid@...r.kernel.org,
        Song Liu <song@...nel.org>
Cc:     Christoph Hellwig <hch@...radead.org>,
        Guoqing Jiang <guoqing.jiang@...ux.dev>,
        Stephen Bates <sbates@...thlin.com>,
        Martin Oliveira <Martin.Oliveira@...eticom.com>,
        David Sloan <David.Sloan@...eticom.com>,
        Logan Gunthorpe <logang@...tatee.com>,
        Christoph Hellwig <hch@....de>
Subject: [PATCH v3 12/15] md/raid5: Check all disks in a stripe_head for reshape progress

When testing if a previous stripe has had reshape expand past it, use
the earliest or latest logical sector in all the disks for that stripe
head. This will allow adding multiple disks at a time in a subesquent
patch.

To do this cleaner, refactor the check into a helper function called
stripe_ahead_of_reshape().

Signed-off-by: Logan Gunthorpe <logang@...tatee.com>
Reviewed-by: Christoph Hellwig <hch@....de>
---
 drivers/md/raid5.c | 53 ++++++++++++++++++++++++++++++++++------------
 1 file changed, 39 insertions(+), 14 deletions(-)

diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index f12773c2387a..b27b754ee18c 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -5818,6 +5818,40 @@ static bool ahead_of_reshape(struct mddev *mddev, sector_t sector,
 					  sector >= reshape_sector;
 }
 
+static bool range_ahead_of_reshape(struct mddev *mddev, sector_t min,
+				   sector_t max, sector_t reshape_sector)
+{
+	return mddev->reshape_backwards ? max < reshape_sector :
+					  min >= reshape_sector;
+}
+
+static bool stripe_ahead_of_reshape(struct mddev *mddev, struct r5conf *conf,
+				    struct stripe_head *sh)
+{
+	sector_t max_sector = 0, min_sector = MaxSector;
+	bool ret = false;
+	int dd_idx;
+
+	for (dd_idx = 0; dd_idx < sh->disks; dd_idx++) {
+		if (dd_idx == sh->pd_idx)
+			continue;
+
+		min_sector = min(min_sector, sh->dev[dd_idx].sector);
+		max_sector = min(max_sector, sh->dev[dd_idx].sector);
+	}
+
+	spin_lock_irq(&conf->device_lock);
+
+	if (!range_ahead_of_reshape(mddev, min_sector, max_sector,
+				     conf->reshape_progress))
+		/* mismatch, need to try again */
+		ret = true;
+
+	spin_unlock_irq(&conf->device_lock);
+
+	return ret;
+}
+
 enum stripe_result {
 	STRIPE_SUCCESS = 0,
 	STRIPE_RETRY,
@@ -5882,27 +5916,18 @@ static enum stripe_result make_stripe_request(struct mddev *mddev,
 		return STRIPE_FAIL;
 	}
 
-	if (unlikely(previous)) {
+	if (unlikely(previous) &&
+	    stripe_ahead_of_reshape(mddev, conf, sh)) {
 		/*
-		 * Expansion might have moved on while waiting for a
-		 * stripe, so we must do the range check again.
+		 * Expansion moved on while waiting for a stripe.
 		 * Expansion could still move past after this
 		 * test, but as we are holding a reference to
 		 * 'sh', we know that if that happens,
 		 *  STRIPE_EXPANDING will get set and the expansion
 		 * won't proceed until we finish with the stripe.
 		 */
-		int must_retry = 0;
-		spin_lock_irq(&conf->device_lock);
-		if (!ahead_of_reshape(mddev, logical_sector,
-				      conf->reshape_progress))
-			/* mismatch, need to try again */
-			must_retry = 1;
-		spin_unlock_irq(&conf->device_lock);
-		if (must_retry) {
-			ret = STRIPE_SCHEDULE_AND_RETRY;
-			goto out_release;
-		}
+		ret = STRIPE_SCHEDULE_AND_RETRY;
+		goto out_release;
 	}
 
 	if (read_seqcount_retry(&conf->gen_lock, seq)) {
-- 
2.30.2