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From: Yufen Yu <yuyufen@huawei.com>
To: <axboe@kernel.dk>
Cc: <linux-block@vger.kernel.org>, <jack@suse.cz>, <hare@suse.de>,
	<ming.lei@redhat.com>, <damien.lemoal@wdc.com>
Subject: [PATCH] block: check disk exist before trying to add partition
Date: Tue, 8 Jun 2021 17:27:07 +0800	[thread overview]
Message-ID: <20210608092707.1062259-1-yuyufen@huawei.com> (raw)

If disk have been deleted, we should return fail for ioctl
BLKPG_DEL_PARTITION. Otherwise, the directory /sys/class/block
may remain invalid symlinks file. The race as following:

blkdev_open
				del_gendisk
				    disk->flags &= ~GENHD_FL_UP;
				    blk_drop_partitions
blkpg_ioctl
    bdev_add_partition
    add_partition
        device_add
	    device_add_class_symlinks

ioctl may add_partition after del_gendisk() have tried to delete
partitions. Then, symlinks file will be created.

Signed-off-by: Yufen Yu <yuyufen@huawei.com>
---
 block/partitions/core.c | 19 ++++++++++++++-----
 1 file changed, 14 insertions(+), 5 deletions(-)

diff --git a/block/partitions/core.c b/block/partitions/core.c
index dc60ecf46fe6..58662a0f48e4 100644
--- a/block/partitions/core.c
+++ b/block/partitions/core.c
@@ -449,17 +449,26 @@ int bdev_add_partition(struct block_device *bdev, int partno,
 		sector_t start, sector_t length)
 {
 	struct block_device *part;
+	struct gendisk *disk = bdev->bd_disk;
+	int ret;
 
 	mutex_lock(&bdev->bd_mutex);
-	if (partition_overlaps(bdev->bd_disk, start, length, -1)) {
-		mutex_unlock(&bdev->bd_mutex);
-		return -EBUSY;
+	if (!(disk->flags & GENHD_FL_UP)) {
+		ret = -ENXIO;
+		goto out;
 	}
 
-	part = add_partition(bdev->bd_disk, partno, start, length,
+	if (partition_overlaps(disk, start, length, -1)) {
+		ret = -EBUSY;
+		goto out;
+	}
+
+	part = add_partition(disk, partno, start, length,
 			ADDPART_FLAG_NONE, NULL);
+	ret = PTR_ERR_OR_ZERO(part);
+out:
 	mutex_unlock(&bdev->bd_mutex);
-	return PTR_ERR_OR_ZERO(part);
+	return ret;
 }
 
 int bdev_del_partition(struct block_device *bdev, int partno)
-- 
2.25.4


             reply	other threads:[~2021-06-08  9:20 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-08  9:27 Yufen Yu [this message]
2021-06-08 10:08 ` Jan Kara
2021-06-08 17:10 ` Christoph Hellwig
2021-06-08 21:08 ` Jens Axboe
2021-06-10  2:30   ` Yufen Yu
2021-06-10  6:28 ` Ming Lei

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