diff options
| -rw-r--r-- | fs/block_dev.c | 25 |
1 files changed, 23 insertions, 2 deletions
diff --git a/fs/block_dev.c b/fs/block_dev.c index fe41a76769fa..fe09ef9c21f3 100644 --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -1058,6 +1058,27 @@ retry: return 0; } +static struct gendisk *bdev_get_gendisk(struct block_device *bdev, int *partno) +{ + struct gendisk *disk = get_gendisk(bdev->bd_dev, partno); + + if (!disk) + return NULL; + /* + * Now that we hold gendisk reference we make sure bdev we looked up is + * not stale. If it is, it means device got removed and created before + * we looked up gendisk and we fail open in such case. Associating + * unhashed bdev with newly created gendisk could lead to two bdevs + * (and thus two independent caches) being associated with one device + * which is bad. + */ + if (inode_unhashed(bdev->bd_inode)) { + put_disk_and_module(disk); + return NULL; + } + return disk; +} + /** * bd_start_claiming - start claiming a block device * @bdev: block device of interest @@ -1094,7 +1115,7 @@ static struct block_device *bd_start_claiming(struct block_device *bdev, * @bdev might not have been initialized properly yet, look up * and grab the outer block device the hard way. */ - disk = get_gendisk(bdev->bd_dev, &partno); + disk = bdev_get_gendisk(bdev, &partno); if (!disk) return ERR_PTR(-ENXIO); @@ -1429,7 +1450,7 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part) restart: ret = -ENXIO; - disk = get_gendisk(bdev->bd_dev, &partno); + disk = bdev_get_gendisk(bdev, &partno); if (!disk) goto out; |