linux-kernel - [PATCH] md: ensure consistent action state in md_do

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Message-Id: <20250830090532.4071221-1-linan666@huaweicloud.com>
Date: Sat, 30 Aug 2025 17:05:32 +0800
From: linan666@...weicloud.com
To: song@...nel.org,
	yukuai3@...wei.com
Cc: linux-raid@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	linan666@...weicloud.com,
	yangerkun@...wei.com,
	yi.zhang@...wei.com
Subject: [PATCH] md: ensure consistent action state in md_do_sync

From: Li Nan <linan122@...wei.com>

The 'mddev->recovery' flags can change during md_do_sync(), leading to
inconsistencies. For example, starting with MD_RECOVERY_RECOVER and
ending with MD_RECOVERY_SYNC can cause incorrect offset updates.

To avoid this, use the 'action' determined at the beginning of the
function instead of repeatedly checking 'mddev->recovery'.

Signed-off-by: Li Nan <linan122@...wei.com>
---
 drivers/md/md.c | 21 +++++++++------------
 1 file changed, 9 insertions(+), 12 deletions(-)

diff --git a/drivers/md/md.c b/drivers/md/md.c
index 6828a569e819..67cda9b64c87 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -9516,7 +9516,7 @@ void md_do_sync(struct md_thread *thread)
 
 		skipped = 0;
 
-		if (!test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery) &&
+		if (action != ACTION_RESHAPE &&
 		    ((mddev->curr_resync > mddev->curr_resync_completed &&
 		      (mddev->curr_resync - mddev->curr_resync_completed)
 		      > (max_sectors >> 4)) ||
@@ -9529,8 +9529,7 @@ void md_do_sync(struct md_thread *thread)
 			wait_event(mddev->recovery_wait,
 				   atomic_read(&mddev->recovery_active) == 0);
 			mddev->curr_resync_completed = j;
-			if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery) &&
-			    j > mddev->resync_offset)
+			if (action == ACTION_RESYNC && j > mddev->resync_offset)
 				mddev->resync_offset = j;
 			update_time = jiffies;
 			set_bit(MD_SB_CHANGE_CLEAN, &mddev->sb_flags);
@@ -9646,7 +9645,7 @@ void md_do_sync(struct md_thread *thread)
 	blk_finish_plug(&plug);
 	wait_event(mddev->recovery_wait, !atomic_read(&mddev->recovery_active));
 
-	if (!test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery) &&
+	if (action != ACTION_RESHAPE &&
 	    !test_bit(MD_RECOVERY_INTR, &mddev->recovery) &&
 	    mddev->curr_resync >= MD_RESYNC_ACTIVE) {
 		mddev->curr_resync_completed = mddev->curr_resync;
@@ -9654,9 +9653,8 @@ void md_do_sync(struct md_thread *thread)
 	}
 	mddev->pers->sync_request(mddev, max_sectors, max_sectors, &skipped);
 
-	if (!test_bit(MD_RECOVERY_CHECK, &mddev->recovery) &&
-	    mddev->curr_resync > MD_RESYNC_ACTIVE) {
-		if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
+	if (action != ACTION_CHECK && mddev->curr_resync > MD_RESYNC_ACTIVE) {
+		if (action == ACTION_RESYNC) {
 			if (test_bit(MD_RECOVERY_INTR, &mddev->recovery)) {
 				if (mddev->curr_resync >= mddev->resync_offset) {
 					pr_debug("md: checkpointing %s of %s.\n",
@@ -9674,8 +9672,7 @@ void md_do_sync(struct md_thread *thread)
 		} else {
 			if (!test_bit(MD_RECOVERY_INTR, &mddev->recovery))
 				mddev->curr_resync = MaxSector;
-			if (!test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery) &&
-			    test_bit(MD_RECOVERY_RECOVER, &mddev->recovery)) {
+			if (action == ACTION_RECOVER) {
 				rcu_read_lock();
 				rdev_for_each_rcu(rdev, mddev)
 					if (mddev->delta_disks >= 0 &&
@@ -9692,7 +9689,7 @@ void md_do_sync(struct md_thread *thread)
 	set_mask_bits(&mddev->sb_flags, 0,
 		      BIT(MD_SB_CHANGE_PENDING) | BIT(MD_SB_CHANGE_DEVS));
 
-	if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery) &&
+	if (action == ACTION_RESHAPE &&
 			!test_bit(MD_RECOVERY_INTR, &mddev->recovery) &&
 			mddev->delta_disks > 0 &&
 			mddev->pers->finish_reshape &&
@@ -9709,10 +9706,10 @@ void md_do_sync(struct md_thread *thread)
 	spin_lock(&mddev->lock);
 	if (!test_bit(MD_RECOVERY_INTR, &mddev->recovery)) {
 		/* We completed so min/max setting can be forgotten if used. */
-		if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
+		if (action == ACTION_REPAIR)
 			mddev->resync_min = 0;
 		mddev->resync_max = MaxSector;
-	} else if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
+	} else if (action == ACTION_REPAIR)
 		mddev->resync_min = mddev->curr_resync_completed;
 	set_bit(MD_RECOVERY_DONE, &mddev->recovery);
 	mddev->curr_resync = MD_RESYNC_NONE;
-- 
2.39.2