From: Yu Kuai yukuai3@huawei.com
mainline inclusion from mainline-v6.3-rc1 commit e5cfefa97bccf956ea0bb6464c1f6c84fd7a8d9f category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I6MQLP CVE: NA
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
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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: stable@vger.kernel.org Suggested-by: Jan Kara jack@suse.cz Signed-off-by: Yu Kuai yukuai3@huawei.com Reviewed-by: Christoph Hellwig hch@lst.de Link: https://lore.kernel.org/r/20230217022200.3092987-3-yukuai1@huaweicloud.com Signed-off-by: Jens Axboe axboe@kernel.dk
Conflicts: block/genhd.c block/ioctl.c Signed-off-by: Yu Kuai yukuai3@huawei.com Reviewed-by: Hou Tao houtao1@huawei.com Signed-off-by: Jialin Zhang zhangjialin11@huawei.com --- block/genhd.c | 38 ++++++++++++++++++++++++++++++++++---- block/ioctl.c | 2 +- 2 files changed, 35 insertions(+), 5 deletions(-)
diff --git a/block/genhd.c b/block/genhd.c index f224381ed46f..b6ad3554876f 100644 --- a/block/genhd.c +++ b/block/genhd.c @@ -739,16 +739,42 @@ static void register_disk(struct device *parent, struct gendisk *disk, int disk_scan_partitions(struct gendisk *disk, fmode_t mode) { struct block_device *bdev; + struct block_device *claim; + int ret = 0;
if (!disk_part_scan_enabled(disk)) return -EINVAL;
+ /* + * 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)) { + claim = bdget_part(&disk->part0); + if (!claim) + return -ENOMEM; + + ret = bd_prepare_to_claim(claim, claim, disk_scan_partitions); + if (ret) { + bdput(claim); + return ret; + } + } + set_bit(GD_NEED_PART_SCAN, &disk->state); - bdev = blkdev_get_by_dev(disk_devt(disk), mode, NULL); + 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(claim, claim, disk_scan_partitions); + bdput(claim); + } + return ret; }
static void disk_init_partition(struct gendisk *disk) @@ -850,6 +876,10 @@ static void __device_add_disk(struct device *parent, struct gendisk *disk, disk_add_events(disk); blk_integrity_add(disk);
+ /* Make sure the first partition scan will be proceed */ + if (get_capacity(disk) && disk_part_scan_enabled(disk)) + set_bit(GD_NEED_PART_SCAN, &disk->state); + /* * Set the flag at last, so that block devcie can't be opened * before it's registration is done. diff --git a/block/ioctl.c b/block/ioctl.c index 565d43c9addd..e3c5a27c23b1 100644 --- a/block/ioctl.c +++ b/block/ioctl.c @@ -543,7 +543,7 @@ static int blkdev_common_ioctl(struct block_device *bdev, fmode_t mode, return -EINVAL; if (bdev->bd_part_count) return -EBUSY; - return disk_scan_partitions(bdev->bd_disk, mode & ~FMODE_EXCL); + return disk_scan_partitions(bdev->bd_disk, mode); case BLKTRACESTART: case BLKTRACESTOP: case BLKTRACETEARDOWN: