Hi,
在 2023/02/12 19:36, Hannes Reinecke 写道:
On 2/12/23 10:26, Yu Kuai wrote:
From: Yu Kuai <yukuai3@xxxxxxxxxx>
In order to prevent scan partition for a device that is opened
exclusively by someone else, new conditions will be added to
disk_scan_partitions() in the next patch. Hence if device is opened
exclusively between bdev_add() and disk_scan_partitions(), the first
partition scan will fail unexpected. This patch factor out the setting
of GD_NEED_PART_SCAN to prevent the problem.
Signed-off-by: Yu Kuai <yukuai3@xxxxxxxxxx>
---
block/genhd.c | 2 +-
block/ioctl.c | 1 +
2 files changed, 2 insertions(+), 1 deletion(-)
diff --git a/block/genhd.c b/block/genhd.c
index 075d8da284f5..c0d1220bd798 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -367,7 +367,6 @@ int disk_scan_partitions(struct gendisk *disk,
fmode_t mode)
if (disk->open_partitions)
return -EBUSY;
- set_bit(GD_NEED_PART_SCAN, &disk->state);
bdev = blkdev_get_by_dev(disk_devt(disk), mode, NULL);
if (IS_ERR(bdev))
return PTR_ERR(bdev);
@@ -493,6 +492,7 @@ int __must_check device_add_disk(struct device
*parent, struct gendisk *disk,
if (ret)
goto out_unregister_bdi;
+ set_bit(GD_NEED_PART_SCAN, &disk->state);
bdev_add(disk->part0, ddev->devt);
if (get_capacity(disk))
disk_scan_partitions(disk, FMODE_READ);
Usual caveat:
What happens if the flag is already set here?
Wouldn't that imply that another scan is underway?
I think this is not true, currently set the state just means we're going
to scan, and if some checking failed, the state will be left. I don't
have a good idea how to fix this yet...
Thanks,
Kuai
And wouldn't it be better to use 'test_and_set()'?
diff --git a/block/ioctl.c b/block/ioctl.c
index 6dd49d877584..0eefcdb936a0 100644
--- a/block/ioctl.c
+++ b/block/ioctl.c
@@ -528,6 +528,7 @@ static int blkdev_common_ioctl(struct block_device
*bdev, fmode_t mode,
return -EACCES;
if (bdev_is_partition(bdev))
return -EINVAL;
+ set_bit(GD_NEED_PART_SCAN, &bdev->bd_disk->state);
return disk_scan_partitions(bdev->bd_disk, mode & ~FMODE_EXCL);
case BLKTRACESTART:
case BLKTRACESTOP:
Similar here.
Cheers,
Hannes
