block: Do not reread partition table on exclusively open device

Since commit 10c70d95c0f2 ("block: remove the bd_openers checks in
blk_drop_partitions") we allow rereading of partition table although
there are users of the block device. This has an undesirable consequence
that e.g. if sda and sdb are assembled to a RAID1 device md0 with
partitions, BLKRRPART ioctl on sda will rescan partition table and
create sda1 device. This partition device under a raid device confuses
some programs (such as libstorage-ng used for initial partitioning for
distribution installation) leading to failures.

Fix the problem refusing to rescan partitions if there is another user
that has the block device exclusively open.

Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/all/20221130135344.2ul4cyfstfs3znxg@quack3
Fixes: 10c70d95c0f2 ("block: remove the bd_openers checks in blk_drop_partitions")
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20221130175653.24299-1-jack@suse.cz
[axboe: fold in followup fix]
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/block/blk.h b/block/blk.h
index a8ac9803fcb36ae57bb7c15ab5bc2e4419539287..8900001946c7d4a499236a42829be7d1c77c742b 100644 (file)
--- a/block/blk.h
+++ b/block/blk.h
@@ -426,7 +426,7 @@ int bio_add_hw_page(struct request_queue *q, struct bio *bio,
 
 struct request_queue *blk_alloc_queue(int node_id);
 
-int disk_scan_partitions(struct gendisk *disk, fmode_t mode);
+int disk_scan_partitions(struct gendisk *disk, fmode_t mode, void *owner);
 
 int disk_alloc_events(struct gendisk *disk);
 void disk_add_events(struct gendisk *disk);

diff --git a/block/genhd.c b/block/genhd.c
index 075d8da284f512ec51a554ff000f1373e11e25a7..52d71a94a809a95dd308c9256b6e985c79b5b3e9 100644 (file)
--- 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)
+int disk_scan_partitions(struct gendisk *disk, fmode_t mode, void *owner)
 {
        struct block_device *bdev;
 
@@ -366,6 +366,9 @@ int disk_scan_partitions(struct gendisk *disk, fmode_t mode)
                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);
@@ -495,7 +498,7 @@ 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);
+                       disk_scan_partitions(disk, FMODE_READ, NULL);
 
                /*
                 * Announce the disk and partitions after all partitions are

diff --git a/block/ioctl.c b/block/ioctl.c
index 60121e89052bcf03b987bcf62ac36e9456dcb6d2..96617512982e57d98a6372400df94114fe4c2447 100644 (file)
--- a/block/ioctl.c
+++ b/block/ioctl.c
@@ -467,9 +467,10 @@ static int blkdev_bszset(struct block_device *bdev, fmode_t mode,
  * user space. Note the separate arg/argp parameters that are needed
  * to deal with the compat_ptr() conversion.
  */
-static int blkdev_common_ioctl(struct block_device *bdev, fmode_t mode,
-                               unsigned cmd, unsigned long arg, void __user *argp)
+static int blkdev_common_ioctl(struct file *file, fmode_t mode, unsigned cmd,
+                              unsigned long arg, void __user *argp)
 {
+       struct block_device *bdev = I_BDEV(file->f_mapping->host);
        unsigned int max_sectors;
 
        switch (cmd) {
@@ -527,7 +528,8 @@ 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 & ~FMODE_EXCL,
+                                           file);
        case BLKTRACESTART:
        case BLKTRACESTOP:
        case BLKTRACETEARDOWN:
@@ -605,7 +607,7 @@ long blkdev_ioctl(struct file *file, unsigned cmd, unsigned long arg)
                break;
        }
 
-       ret = blkdev_common_ioctl(bdev, mode, cmd, arg, argp);
+       ret = blkdev_common_ioctl(file, mode, cmd, arg, argp);
        if (ret != -ENOIOCTLCMD)
                return ret;
 
@@ -674,7 +676,7 @@ long compat_blkdev_ioctl(struct file *file, unsigned cmd, unsigned long arg)
                break;
        }
 
-       ret = blkdev_common_ioctl(bdev, mode, cmd, arg, argp);
+       ret = blkdev_common_ioctl(file, mode, cmd, arg, argp);
        if (ret == -ENOIOCTLCMD && disk->fops->compat_ioctl)
                ret = disk->fops->compat_ioctl(bdev, mode, cmd, arg);