From 0f77b29ad14e34a89961f32edc87b92db623bb37 Mon Sep 17 00:00:00 2001 From: Yu Kuai Date: Fri, 17 Feb 2023 10:21:59 +0800 Subject: block: Revert "block: Do not reread partition table on exclusively open device" This reverts commit 36369f46e91785688a5f39d7a5590e3f07981316. This patch can't fix the problem in a corner case that device can be opened exclusively after the checking and before blkdev_get_by_dev(). We'll use a new solution to fix the problem in the next patch, and the new solution doesn't need to change apis. Signed-off-by: Yu Kuai Acked-by: Jan Kara Link: https://lore.kernel.org/r/20230217022200.3092987-2-yukuai1@huaweicloud.com Signed-off-by: Jens Axboe --- block/genhd.c | 7 ++----- 1 file changed, 2 insertions(+), 5 deletions(-) (limited to 'block/genhd.c') diff --git a/block/genhd.c b/block/genhd.c index 093ef292e98f..820e27d88cbf 100644 --- a/block/genhd.c +++ b/block/genhd.c @@ -356,7 +356,7 @@ void disk_uevent(struct gendisk *disk, enum kobject_action action) } EXPORT_SYMBOL_GPL(disk_uevent); -int disk_scan_partitions(struct gendisk *disk, fmode_t mode, void *owner) +int disk_scan_partitions(struct gendisk *disk, fmode_t mode) { struct block_device *bdev; @@ -366,9 +366,6 @@ int disk_scan_partitions(struct gendisk *disk, fmode_t mode, void *owner) return -EINVAL; if (disk->open_partitions) return -EBUSY; - /* Someone else has bdev exclusively open? */ - if (disk->part0->bd_holder && disk->part0->bd_holder != owner) - return -EBUSY; set_bit(GD_NEED_PART_SCAN, &disk->state); bdev = blkdev_get_by_dev(disk_devt(disk), mode, NULL); @@ -499,7 +496,7 @@ int __must_check device_add_disk(struct device *parent, struct gendisk *disk, bdev_add(disk->part0, ddev->devt); if (get_capacity(disk)) - disk_scan_partitions(disk, FMODE_READ, NULL); + disk_scan_partitions(disk, FMODE_READ); /* * Announce the disk and partitions after all partitions are -- cgit v1.2.3 From e5cfefa97bccf956ea0bb6464c1f6c84fd7a8d9f Mon Sep 17 00:00:00 2001 From: Yu Kuai Date: Fri, 17 Feb 2023 10:22:00 +0800 Subject: block: fix scan partition for exclusively open device again As explained in commit 36369f46e917 ("block: Do not reread partition table on exclusively open device"), reread partition on the device that is exclusively opened by someone else is problematic. This patch will make sure partition scan will only be proceed if current thread open the device exclusively, or the device is not opened exclusively, and in the later case, other scanners and exclusive openers will be blocked temporarily until partition scan is done. Fixes: 10c70d95c0f2 ("block: remove the bd_openers checks in blk_drop_partitions") Cc: Suggested-by: Jan Kara Signed-off-by: Yu Kuai Reviewed-by: Christoph Hellwig Link: https://lore.kernel.org/r/20230217022200.3092987-3-yukuai1@huaweicloud.com Signed-off-by: Jens Axboe --- block/genhd.c | 30 ++++++++++++++++++++++++++---- block/ioctl.c | 2 +- 2 files changed, 27 insertions(+), 5 deletions(-) (limited to 'block/genhd.c') diff --git a/block/genhd.c b/block/genhd.c index 820e27d88cbf..c0a73cd76bb1 100644 --- a/block/genhd.c +++ b/block/genhd.c @@ -359,6 +359,7 @@ EXPORT_SYMBOL_GPL(disk_uevent); int disk_scan_partitions(struct gendisk *disk, fmode_t mode) { struct block_device *bdev; + int ret = 0; if (disk->flags & (GENHD_FL_NO_PART | GENHD_FL_HIDDEN)) return -EINVAL; @@ -368,11 +369,27 @@ int disk_scan_partitions(struct gendisk *disk, fmode_t mode) return -EBUSY; set_bit(GD_NEED_PART_SCAN, &disk->state); - bdev = blkdev_get_by_dev(disk_devt(disk), mode, NULL); + /* + * If the device is opened exclusively by current thread already, it's + * safe to scan partitons, otherwise, use bd_prepare_to_claim() to + * synchronize with other exclusive openers and other partition + * scanners. + */ + if (!(mode & FMODE_EXCL)) { + ret = bd_prepare_to_claim(disk->part0, disk_scan_partitions); + if (ret) + return ret; + } + + bdev = blkdev_get_by_dev(disk_devt(disk), mode & ~FMODE_EXCL, NULL); if (IS_ERR(bdev)) - return PTR_ERR(bdev); - blkdev_put(bdev, mode); - return 0; + ret = PTR_ERR(bdev); + else + blkdev_put(bdev, mode); + + if (!(mode & FMODE_EXCL)) + bd_abort_claiming(disk->part0, disk_scan_partitions); + return ret; } /** @@ -494,6 +511,11 @@ int __must_check device_add_disk(struct device *parent, struct gendisk *disk, if (ret) goto out_unregister_bdi; + /* Make sure the first partition scan will be proceed */ + if (get_capacity(disk) && !(disk->flags & GENHD_FL_NO_PART) && + !test_bit(GD_SUPPRESS_PART_SCAN, &disk->state)) + set_bit(GD_NEED_PART_SCAN, &disk->state); + bdev_add(disk->part0, ddev->devt); if (get_capacity(disk)) disk_scan_partitions(disk, FMODE_READ); diff --git a/block/ioctl.c b/block/ioctl.c index 6dd49d877584..9c5f637ff153 100644 --- a/block/ioctl.c +++ b/block/ioctl.c @@ -528,7 +528,7 @@ static int blkdev_common_ioctl(struct block_device *bdev, fmode_t mode, return -EACCES; if (bdev_is_partition(bdev)) return -EINVAL; - return disk_scan_partitions(bdev->bd_disk, mode & ~FMODE_EXCL); + return disk_scan_partitions(bdev->bd_disk, mode); case BLKTRACESTART: case BLKTRACESTOP: case BLKTRACETEARDOWN: -- cgit v1.2.3