block: move bdev_mark_dead out of disk_check_media_change

disk_check_media_change is mostly called from ->open where it makes
little sense to mark the file system on the device as dead, as we
are just opening it.  So instead of calling bdev_mark_dead from
disk_check_media_change move it into the few callers that are not
in an open instance.  This avoid calling into bdev_mark_dead and
thus taking s_umount with open_mutex held.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20231017184823.1383356-4-hch@lst.de
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Christian Brauner <brauner@kernel.org>

2 files changed, 11 insertions, 16 deletions

diff --git a/block/bdev.c b/block/bdev.c
index 9838085102b3..2018d250e131 100644
--- a/block/bdev.c
+++ b/block/bdev.c
@@ -1019,14 +1019,13 @@ void bdev_mark_dead(struct block_device *bdev, bool surprise)
 
 	invalidate_bdev(bdev);
 }
-#ifdef CONFIG_DASD_MODULE
 /*
- * Drivers should not use this directly, but the DASD driver has historically
- * had a shutdown to offline mode that doesn't actually remove the gendisk
- * that otherwise looks a lot like a safe device removal.
+ * New drivers should not use this directly.  There are some drivers however
+ * that needs this for historical reasons. For example, the DASD driver has
+ * historically had a shutdown to offline mode that doesn't actually remove the
+ * gendisk that otherwise looks a lot like a safe device removal.
  */
 EXPORT_SYMBOL_GPL(bdev_mark_dead);
-#endif
 
 void sync_bdevs(bool wait)
 {
diff --git a/block/disk-events.c b/block/disk-events.c
index 13c3372c465a..2f697224386a 100644
--- a/block/disk-events.c
+++ b/block/disk-events.c
@@ -266,11 +266,8 @@ static unsigned int disk_clear_events(struct gendisk *disk, unsigned int mask)
  * disk_check_media_change - check if a removable media has been changed
  * @disk: gendisk to check
  *
- * Check whether a removable media has been changed, and attempt to free all
- * dentries and inodes and invalidates all block device page cache entries in
- * that case.
- *
- * Returns %true if the media has changed, or %false if not.
+ * Returns %true and marks the disk for a partition rescan whether a removable
+ * media has been changed, and %false if the media did not change.
  */
 bool disk_check_media_change(struct gendisk *disk)
 {
@@ -278,12 +275,11 @@ bool disk_check_media_change(struct gendisk *disk)
 
 	events = disk_clear_events(disk, DISK_EVENT_MEDIA_CHANGE |
 				   DISK_EVENT_EJECT_REQUEST);
-	if (!(events & DISK_EVENT_MEDIA_CHANGE))
-		return false;
-
-	bdev_mark_dead(disk->part0, true);
-	set_bit(GD_NEED_PART_SCAN, &disk->state);
-	return true;
+	if (events & DISK_EVENT_MEDIA_CHANGE) {
+		set_bit(GD_NEED_PART_SCAN, &disk->state);
+		return true;
+	}
+	return false;
 }
 EXPORT_SYMBOL(disk_check_media_change);