linux-kernel - [PATCH -next v3 18/25] md: use new apis to suspend array for ioctls involed array reconfiguration

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Message-Id: <20230928061543.1845742-19-yukuai1@huaweicloud.com>
Date:   Thu, 28 Sep 2023 14:15:36 +0800
From:   Yu Kuai <yukuai1@...weicloud.com>
To:     xni@...hat.com, agk@...hat.com, snitzer@...nel.org,
        dm-devel@...hat.com, song@...nel.org
Cc:     linux-kernel@...r.kernel.org, linux-raid@...r.kernel.org,
        yukuai3@...wei.com, yukuai1@...weicloud.com, yi.zhang@...wei.com,
        yangerkun@...wei.com
Subject: [PATCH -next v3 18/25] md: use new apis to suspend array for ioctls involed array reconfiguration

From: Yu Kuai <yukuai3@...wei.com>

'reconfig_mutex' will be grabbed before these ioctls, suspend array
before holding the lock, so that io won't concurrent with array
reconfiguration through ioctls.

This is not hot path, so performance is not concerned.

Signed-off-by: Yu Kuai <yukuai3@...wei.com>
---
 drivers/md/md.c | 30 ++++++++++++++++++++----------
 1 file changed, 20 insertions(+), 10 deletions(-)

diff --git a/drivers/md/md.c b/drivers/md/md.c
index 0c5a6169453c..957813b7d7e5 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -7209,7 +7209,6 @@ static int set_bitmap_file(struct mddev *mddev, int fd)
 			struct bitmap *bitmap;
 
 			bitmap = md_bitmap_create(mddev, -1);
-			mddev_suspend(mddev);
 			if (!IS_ERR(bitmap)) {
 				mddev->bitmap = bitmap;
 				err = md_bitmap_load(mddev);
@@ -7219,11 +7218,8 @@ static int set_bitmap_file(struct mddev *mddev, int fd)
 				md_bitmap_destroy(mddev);
 				fd = -1;
 			}
-			mddev_resume(mddev);
 		} else if (fd < 0) {
-			mddev_suspend(mddev);
 			md_bitmap_destroy(mddev);
-			mddev_resume(mddev);
 		}
 	}
 	if (fd < 0) {
@@ -7512,7 +7508,6 @@ static int update_array_info(struct mddev *mddev, mdu_array_info_t *info)
 			mddev->bitmap_info.space =
 				mddev->bitmap_info.default_space;
 			bitmap = md_bitmap_create(mddev, -1);
-			mddev_suspend(mddev);
 			if (!IS_ERR(bitmap)) {
 				mddev->bitmap = bitmap;
 				rv = md_bitmap_load(mddev);
@@ -7520,7 +7515,6 @@ static int update_array_info(struct mddev *mddev, mdu_array_info_t *info)
 				rv = PTR_ERR(bitmap);
 			if (rv)
 				md_bitmap_destroy(mddev);
-			mddev_resume(mddev);
 		} else {
 			/* remove the bitmap */
 			if (!mddev->bitmap) {
@@ -7545,9 +7539,7 @@ static int update_array_info(struct mddev *mddev, mdu_array_info_t *info)
 				module_put(md_cluster_mod);
 				mddev->safemode_delay = DEFAULT_SAFEMODE_DELAY;
 			}
-			mddev_suspend(mddev);
 			md_bitmap_destroy(mddev);
-			mddev_resume(mddev);
 			mddev->bitmap_info.offset = 0;
 		}
 	}
@@ -7618,6 +7610,20 @@ static inline bool md_ioctl_valid(unsigned int cmd)
 	}
 }
 
+static bool md_ioctl_need_suspend(unsigned int cmd)
+{
+	switch (cmd) {
+	case ADD_NEW_DISK:
+	case HOT_ADD_DISK:
+	case HOT_REMOVE_DISK:
+	case SET_BITMAP_FILE:
+	case SET_ARRAY_INFO:
+		return true;
+	default:
+		return false;
+	}
+}
+
 static int __md_set_array_info(struct mddev *mddev, void __user *argp)
 {
 	mdu_array_info_t info;
@@ -7750,7 +7756,8 @@ static int md_ioctl(struct block_device *bdev, blk_mode_t mode,
 	if (!md_is_rdwr(mddev))
 		flush_work(&mddev->sync_work);
 
-	err = mddev_lock(mddev);
+	err = md_ioctl_need_suspend(cmd) ? mddev_suspend_and_lock(mddev) :
+					   mddev_lock(mddev);
 	if (err) {
 		pr_debug("md: ioctl lock interrupted, reason %d, cmd %d\n",
 			 err, cmd);
@@ -7878,7 +7885,10 @@ static int md_ioctl(struct block_device *bdev, blk_mode_t mode,
 	if (mddev->hold_active == UNTIL_IOCTL &&
 	    err != -EINVAL)
 		mddev->hold_active = 0;
-	mddev_unlock(mddev);
+
+	md_ioctl_need_suspend(cmd) ? mddev_unlock_and_resume(mddev) :
+				     mddev_unlock(mddev);
+
 out:
 	if(did_set_md_closing)
 		clear_bit(MD_CLOSING, &mddev->flags);
-- 
2.39.2