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block: check disk exist before trying to add partition

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If disk have been deleted, we should return fail for ioctl
BLKPG_DEL_PARTITION. Otherwise, the directory /sys/class/block
may remain invalid symlinks file. The race as following:

blkdev_open
				del_gendisk
				    disk->flags &= ~GENHD_FL_UP;
				    blk_drop_partitions
blkpg_ioctl
    bdev_add_partition
    add_partition
        device_add
	    device_add_class_symlinks

ioctl may add_partition after del_gendisk() have tried to delete
partitions. Then, symlinks file will be created.

Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Yufen Yu <yuyufen@huawei.com>
Link: https://lore.kernel.org/r/20210610023241.3646241-1-yuyufen@huawei.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Yufen Yu 2021-06-10 10:32:41 +08:00 • committed by Jens Axboe
parent efee99e68e
commit b5cfbd35ec
1 changed files with 16 additions and 7 deletions
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23
block/partitions/core.c
View file

@ -453,17 +453,26 @@ int bdev_add_partition(struct block_device *bdev, int partno,
sector_t start, sector_t length)
{
struct block_device *part;
struct gendisk *disk = bdev->bd_disk;
int ret;
mutex_lock(&bdev->bd_disk->open_mutex);
if (partition_overlaps(bdev->bd_disk, start, length, -1)) {
mutex_unlock(&bdev->bd_disk->open_mutex);
return -EBUSY;
mutex_lock(&disk->open_mutex);
if (!(disk->flags & GENHD_FL_UP)) {
ret = -ENXIO;
goto out;
}
part = add_partition(bdev->bd_disk, partno, start, length,
if (partition_overlaps(disk, start, length, -1)) {
ret = -EBUSY;
goto out;
}
part = add_partition(disk, partno, start, length,
ADDPART_FLAG_NONE, NULL);
mutex_unlock(&bdev->bd_disk->open_mutex);
return PTR_ERR_OR_ZERO(part);
ret = PTR_ERR_OR_ZERO(part);
out:
mutex_unlock(&disk->open_mutex);
return ret;
}
int bdev_del_partition(struct block_device *bdev, int partno)