[PATCH v2] dm init: ensure block device is ready before creating mapped device

jaeyuel.im
2025-12-12T00:10:01Z

Changes in v2:
- Pass autoload parameter for new blkdev_get_no_open()

Signed-off-by: jaeyuel.im <jaeyuel.im@lge.com>
---
drivers/md/dm-init.c | 14 ++++++++++++++
1 file changed, 14 insertions(+)

diff --git a/drivers/md/dm-init.c b/drivers/md/dm-init.c
index b37bbe762500..b3905e094ffc 100644
--- a/drivers/md/dm-init.c
+++ b/drivers/md/dm-init.c
@@ -296,10 +296,24 @@ static int __init dm_init_init(void)
for (i = 0; i < ARRAY_SIZE(waitfor); i++) {
if (waitfor[i]) {
dev_t dev;
+ struct block_device *bdev;

DMINFO("waiting for device %s ...", waitfor[i]);
while (early_lookup_bdev(waitfor[i], &dev))
fsleep(5000);
+
+ /*
+ * early_lookup_bdev() only checks if the device node exists and
+ * returns the dev_t. It does not guarantee that the underlying
+ * block device is fully initialized and ready to be opened. On
+ * some platforms, this can lead to a race condition where
+ * dm_early_create() fails because the device is not yet ready.
+ * Ensure the block device is truly available by attempting to
+ * get it.
+ */
+ while (!(bdev = blkdev_get_no_open(dev, false)))