block: fix __blkdev_get() for removable devices
Commit 0762b8bde9
moved disk_get_part()
in front of recursive get on the whole disk, which caused removable
devices to try disk_get_part() before rescanning after a new media is
inserted, which might fail legit open attempts or give the old
partition.
This patch fixes the problem by moving disk_get_part() after
__blkdev_get() on the whole disk.
This problem was spotted by Borislav Petkov.
Signed-off-by: Tejun Heo <tj@kernel.org>
Tested-by: Borislav Petkov <petkovbb@gmail.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
This commit is contained in:
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561920a0d2
commit
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@ -986,7 +986,6 @@ static int __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part);
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static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part)
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{
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struct gendisk *disk;
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struct hd_struct *part = NULL;
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int ret;
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int partno;
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int perm = 0;
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@ -1004,24 +1003,25 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part)
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return ret;
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}
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ret = -ENXIO;
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lock_kernel();
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ret = -ENXIO;
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disk = get_gendisk(bdev->bd_dev, &partno);
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if (!disk)
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goto out_unlock_kernel;
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part = disk_get_part(disk, partno);
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if (!part)
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goto out_unlock_kernel;
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mutex_lock_nested(&bdev->bd_mutex, for_part);
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if (!bdev->bd_openers) {
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bdev->bd_disk = disk;
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bdev->bd_part = part;
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bdev->bd_contains = bdev;
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if (!partno) {
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struct backing_dev_info *bdi;
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ret = -ENXIO;
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bdev->bd_part = disk_get_part(disk, partno);
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if (!bdev->bd_part)
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goto out_clear;
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if (disk->fops->open) {
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ret = disk->fops->open(bdev, mode);
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if (ret)
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@ -1049,18 +1049,17 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part)
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bdev->bd_contains = whole;
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bdev->bd_inode->i_data.backing_dev_info =
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whole->bd_inode->i_data.backing_dev_info;
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bdev->bd_part = disk_get_part(disk, partno);
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if (!(disk->flags & GENHD_FL_UP) ||
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!part || !part->nr_sects) {
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!bdev->bd_part || !bdev->bd_part->nr_sects) {
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ret = -ENXIO;
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goto out_clear;
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}
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bd_set_size(bdev, (loff_t)part->nr_sects << 9);
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bd_set_size(bdev, (loff_t)bdev->bd_part->nr_sects << 9);
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}
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} else {
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disk_put_part(part);
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put_disk(disk);
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module_put(disk->fops->owner);
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part = NULL;
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disk = NULL;
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if (bdev->bd_contains == bdev) {
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if (bdev->bd_disk->fops->open) {
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@ -1080,6 +1079,7 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part)
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return 0;
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out_clear:
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disk_put_part(bdev->bd_part);
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bdev->bd_disk = NULL;
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bdev->bd_part = NULL;
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bdev->bd_inode->i_data.backing_dev_info = &default_backing_dev_info;
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@ -1091,7 +1091,6 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part)
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out_unlock_kernel:
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unlock_kernel();
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disk_put_part(part);
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if (disk)
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module_put(disk->fops->owner);
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put_disk(disk);
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