Commit 1196f8b8 authored by Tejun Heo's avatar Tejun Heo Committed by Jens Axboe
Browse files

block: rescan partitions on invalidated devices on -ENOMEDIA too 

__blkdev_get() doesn't rescan partitions if disk->fops->open() fails,
which leads to ghost partition devices lingering after medimum removal
is known to both the kernel and userland.  The behavior also creates a
subtle inconsistency where O_NONBLOCK open, which doesn't fail even if
there's no medium, clears the ghots partitions, which is exploited to
work around the problem from userland.

Fix it by updating __blkdev_get() to issue partition rescan after
-ENOMEDIA too.

This was reported in the following bz.

 https://bugzilla.kernel.org/show_bug.cgi?id=13029



Note for stable: 2.6.38 and later only

Cc: stable@kernel.org
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Reported-by: default avatarDavid Zeuthen <zeuthen@gmail.com>
Reported-by: default avatarMartin Pitt <martin.pitt@ubuntu.com>
Reported-by: default avatarKay Sievers <kay.sievers@vrfy.org>
Tested-by: default avatarKay Sievers <kay.sievers@vrfy.org>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: default avatarJens Axboe <jaxboe@fusionio.com>
parent ea6949b6

fs/block_dev.c

+18 −9
Original line number Diff line number Diff line
@@ -1102,6 +1102,7 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part) 
			if (!bdev->bd_part)

				goto out_clear;



			ret = 0;

			if (disk->fops->open) {

				ret = disk->fops->open(bdev, mode);

				if (ret == -ERESTARTSYS) {
@@ -1118,9 +1119,18 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part) 
					put_disk(disk);

					goto restart;

				}

			}

			/*

			 * If the device is invalidated, rescan partition

			 * if open succeeded or failed with -ENOMEDIUM.

			 * The latter is necessary to prevent ghost

			 * partitions on a removed medium.

			 */

			if (bdev->bd_invalidated && (!ret || ret == -ENOMEDIUM))

				rescan_partitions(disk, bdev);

			if (ret)

				goto out_clear;

			}



			if (!bdev->bd_openers) {

				bd_set_size(bdev,(loff_t)get_capacity(disk)<<9);

				bdi = blk_get_backing_dev_info(bdev);
@@ -1128,8 +1138,6 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part) 
					bdi = &default_backing_dev_info;

				bdev_inode_switch_bdi(bdev->bd_inode, bdi);

			}

			if (bdev->bd_invalidated)

				rescan_partitions(disk, bdev);

		} else {

			struct block_device *whole;

			whole = bdget_disk(disk, 0);
@@ -1153,14 +1161,15 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part) 
		}

	} else {

		if (bdev->bd_contains == bdev) {

			if (bdev->bd_disk->fops->open) {

			ret = 0;

			if (bdev->bd_disk->fops->open)

				ret = bdev->bd_disk->fops->open(bdev, mode);

			/* the same as first opener case, read comment there */

			if (bdev->bd_invalidated && (!ret || ret == -ENOMEDIUM))

				rescan_partitions(bdev->bd_disk, bdev);

			if (ret)

				goto out_unlock_bdev;

		}

			if (bdev->bd_invalidated)

				rescan_partitions(bdev->bd_disk, bdev);

		}

		/* only one opener holds refs to the module and disk */

		module_put(disk->fops->owner);

		put_disk(disk);

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