block: take bd_mutex around delete_partitions in del_gendisk

There is nothing preventing an ioctl from trying do delete partition concurrenly with del_gendisk, so take open_mutex to serialize against that. Signed-off-by: Christoph Hellwig <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Jens Axboe <[email protected]>
xovano · Apr 8, 2021 · c76f48e · c76f48e
1 parent d3c4a43
commit c76f48e
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diff --git a/block/genhd.c b/block/genhd.c
@@ -680,7 +680,11 @@ void del_gendisk(struct gendisk *disk)
 	 * disk is marked as dead (GENHD_FL_UP cleared).
 	 */
 	down_write(&bdev_lookup_sem);
+
+	mutex_lock(&disk->part0->bd_mutex);
 	blk_drop_partitions(disk);
+	mutex_unlock(&disk->part0->bd_mutex);
+
 	fsync_bdev(disk->part0);
 	__invalidate_device(disk->part0, true);
 

diff --git a/block/partitions/core.c b/block/partitions/core.c
@@ -531,6 +531,8 @@ void blk_drop_partitions(struct gendisk *disk)
 	struct disk_part_iter piter;
 	struct block_device *part;
 
+	lockdep_assert_held(&disk->part0->bd_mutex);
+
 	disk_part_iter_init(&piter, disk, DISK_PITER_INCL_EMPTY);
 	while ((part = disk_part_iter_next(&piter)))
 		delete_partition(part);