[PATCH 4.19 022/148] md: implement ->set_read_only to hook into BLKROSET processing

[Sasha Levin]

From: Christoph Hellwig <hch@xxxxxx>

[ Upstream commit 118cf084adb3964d06e1667cf7d702e56e5cd2c5 ]

Implement the ->set_read_only method instead of parsing the actual
ioctl command.

Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Acked-by: Song Liu <song@xxxxxxxxxx>
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Stable-dep-of: 9674f54e41ff ("md: Don't clear MD_CLOSING when the raid is about to stop")
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/md/md.c | 62 ++++++++++++++++++++++++-------------------------
 1 file changed, 31 insertions(+), 31 deletions(-)

diff --git a/drivers/md/md.c b/drivers/md/md.c
index a137f8b4a0541..8123c44de7dc8 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -7172,7 +7172,6 @@ static inline bool md_ioctl_valid(unsigned int cmd)
 {
 	switch (cmd) {
 	case ADD_NEW_DISK:
-	case BLKROSET:
 	case GET_ARRAY_INFO:
 	case GET_BITMAP_FILE:
 	case GET_DISK_INFO:
@@ -7200,7 +7199,6 @@ static int md_ioctl(struct block_device *bdev, fmode_t mode,
 	int err = 0;
 	void __user *argp = (void __user *)arg;
 	struct mddev *mddev = NULL;
-	int ro;
 	bool did_set_md_closing = false;
 
 	if (!md_ioctl_valid(cmd))
@@ -7391,35 +7389,6 @@ static int md_ioctl(struct block_device *bdev, fmode_t mode,
 			goto unlock;
 		}
 		break;
-
-	case BLKROSET:
-		if (get_user(ro, (int __user *)(arg))) {
-			err = -EFAULT;
-			goto unlock;
-		}
-		err = -EINVAL;
-
-		/* if the bdev is going readonly the value of mddev->ro
-		 * does not matter, no writes are coming
-		 */
-		if (ro)
-			goto unlock;
-
-		/* are we are already prepared for writes? */
-		if (mddev->ro != 1)
-			goto unlock;
-
-		/* transitioning to readauto need only happen for
-		 * arrays that call md_write_start
-		 */
-		if (mddev->pers) {
-			err = restart_array(mddev);
-			if (err == 0) {
-				mddev->ro = 2;
-				set_disk_ro(mddev->gendisk, 0);
-			}
-		}
-		goto unlock;
 	}
 
 	/*
@@ -7513,6 +7482,36 @@ static int md_compat_ioctl(struct block_device *bdev, fmode_t mode,
 }
 #endif /* CONFIG_COMPAT */
 
+static int md_set_read_only(struct block_device *bdev, bool ro)
+{
+	struct mddev *mddev = bdev->bd_disk->private_data;
+	int err;
+
+	err = mddev_lock(mddev);
+	if (err)
+		return err;
+
+	if (!mddev->raid_disks && !mddev->external) {
+		err = -ENODEV;
+		goto out_unlock;
+	}
+
+	/*
+	 * Transitioning to read-auto need only happen for arrays that call
+	 * md_write_start and which are not ready for writes yet.
+	 */
+	if (!ro && mddev->ro == 1 && mddev->pers) {
+		err = restart_array(mddev);
+		if (err)
+			goto out_unlock;
+		mddev->ro = 2;
+	}
+
+out_unlock:
+	mddev_unlock(mddev);
+	return err;
+}
+
 static int md_open(struct block_device *bdev, fmode_t mode)
 {
 	/*
@@ -7588,6 +7587,7 @@ static const struct block_device_operations md_fops =
 #endif
 	.getgeo		= md_getgeo,
 	.check_events	= md_check_events,
+	.set_read_only	= md_set_read_only,
 };
 
 static int md_thread(void *arg)
-- 
2.43.0