linux.git/block/partitions/core.c, branch v6.7

block: WARN_ON_ONCE() when we remove active partitions

2023-10-28T11:29:22+00:00

The logic for disk->open_partitions is:

blkdev_get_by_*()
-> bdev_is_partition()
   -> blkdev_get_part()
      -> blkdev_get_whole() // bdev_whole->bd_openers++
      -> if (part->bd_openers == 0)
                 disk->open_partitions++
         part->bd_openers

In other words, when we first claim/open a partition we increment
disk->open_partitions and only when all part->bd_openers are closed will
disk->open_partitions be zero. That should mean that
disk->open_partitions is always > 0 as long as there's anyone that
has an open partition.

So the check for disk->open_partitions should mean that we can never
remove an active partition that has a holder and holder ops set. Assert
that in the code. The main disk isn't removed so that check doesn't work
for disk->part0 which is what we want. After all we only care about
partition not about the main disk.

Link: https://lore.kernel.org/r/20231017184823.1383356-3-hch@lst.de
Reviewed-by: Ming Lei 
Reviewed-by: Jan Kara 
Reviewed-by: Jens Axboe 
Signed-off-by: Christian Brauner

block: simplify bdev_del_partition()

2023-10-28T11:29:22+00:00

BLKPG_DEL_PARTITION refuses to delete partitions that still have
openers, i.e., that has an elevated @bdev->bd_openers count. If a device
is claimed by setting @bdev->bd_holder and @bdev->bd_holder_ops
@bdev->bd_openers and @bdev->bd_holders are incremented.
@bdev->bd_openers is effectively guaranteed to be >= @bdev->bd_holders.
So as long as @bdev->bd_openers isn't zero we know that this partition
is still in active use and that there might still be @bdev->bd_holder
and @bdev->bd_holder_ops set.

The only current example is @fs_holder_ops for filesystems. But that
means bdev_mark_dead() which calls into
bdev->bd_holder_ops->mark_dead::fs_bdev_mark_dead() is a nop. As long as
there's an elevated @bdev->bd_openers count we can't delete the
partition and if there isn't an elevated @bdev->bd_openers count then
there's no @bdev->bd_holder or @bdev->bd_holder_ops.

So simply open-code what we need to do. This gets rid of one more
instance where we acquire s_umount under @disk->open_mutex.

Link: https://lore.kernel.org/r/20231016-fototermin-umriss-59f1ea6c1fe6@brauner
Reviewed-by: Christoph Hellwig 
Reviewed-by: Jan Kara 
Reviewed-by: Jens Axboe 
Signed-off-by: Christoph Hellwig 
Link: https://lore.kernel.org/r/20231017184823.1383356-2-hch@lst.de
Reviewed-by: Ming Lei 
Signed-off-by: Christian Brauner

block: consolidate __invalidate_device and fsync_bdev

2023-08-21T12:35:31+00:00

We currently have two interfaces that take a block_devices and the find
a mounted file systems to flush or invaldidate data on it.  Both are a
bit problematic because they only work for the "main" block devices
that is used as s_dev for the super_block, and because they don't call
into the file system at all.

Merge the two into a new bdev_mark_dead helper that does both the
syncing and invalidation and which is properly documented.  This is
in preparation of merging the functionality into the ->mark_dead
holder operation so that it will work on additional block devices
used by a file systems and give us a single entry point for invalidation
of dead devices or media.

Note that a single standalone fsync_bdev call for an obscure ioctl
remains for now, but that one will also be deal with in a bit.

Signed-off-by: Christoph Hellwig 
Reviewed-by: Josef Bacik 
Message-Id: <20230811100828.1897174-14-hch@lst.de>
Signed-off-by: Christian Brauner

block: add capacity validation in bdev_add_partition()

2023-06-20T18:50:51+00:00

In the function bdev_add_partition(),there is no check that the start
and end sectors exceed the size of the disk before calling add_partition.
When we call the block's ioctl interface directly to add a partition,
and the capacity of the disk is set to 0 by driver,the command will
continue to execute.

Signed-off-by: Min Li 
Reviewed-by: Christoph Hellwig 
Reviewed-by: Damien Le Moal 
Link: https://lore.kernel.org/r/20230619091214.31615-1-min15.li@samsung.com
Signed-off-by: Jens Axboe

block: remove blk_drop_partitions

2023-06-05T16:53:04+00:00

There is only a single caller left, so fold the loop into that.

Signed-off-by: Christoph Hellwig 
Reviewed-by: Jan Kara 
Acked-by: Dave Chinner 
Reviewed-by: Dave Chinner 
Link: https://lore.kernel.org/r/20230601094459.1350643-9-hch@lst.de
Signed-off-by: Jens Axboe

block: delete partitions later in del_gendisk

2023-06-05T16:53:04+00:00

Delay dropping the block_devices for partitions in del_gendisk until
after the call to blk_mark_disk_dead, so that we can implementat
notification of removed devices in blk_mark_disk_dead.

This requires splitting a lower-level drop_partition helper out of
delete_partition and using that from del_gendisk, while having a
common loop for the whole device and partitions that calls
remove_inode_hash, fsync_bdev and __invalidate_device before the
call to blk_mark_disk_dead.

Signed-off-by: Christoph Hellwig 
Reviewed-by: Jan Kara 
Acked-by: Dave Chinner 
Reviewed-by: Dave Chinner 
Link: https://lore.kernel.org/r/20230601094459.1350643-8-hch@lst.de
Signed-off-by: Jens Axboe

block: unhash the inode earlier in delete_partition

2023-06-05T16:53:04+00:00

Move the call to remove_inode_hash to the beginning of delete_partition,
as we want to prevent opening a block_device that is about to be removed
ASAP.

Signed-off-by: Christoph Hellwig 
Reviewed-by: Jan Kara 
Acked-by: Dave Chinner 
Reviewed-by: Dave Chinner 
Link: https://lore.kernel.org/r/20230601094459.1350643-7-hch@lst.de
Signed-off-by: Jens Axboe

block: constify the whole_disk device_attribute

2023-05-30T17:12:43+00:00

The struct is never modified so it can be const.

Signed-off-by: Thomas Weißschuh 
Link: https://lore.kernel.org/r/20230419-const-partition-v3-4-4e14e48be367@weissschuh.net
Signed-off-by: Jens Axboe

block: constify struct part_attr_group

2023-05-30T17:12:43+00:00

The struct is never modified so it can be const.

Signed-off-by: Thomas Weißschuh 
Link: https://lore.kernel.org/r/20230419-const-partition-v3-3-4e14e48be367@weissschuh.net
Signed-off-by: Jens Axboe

block: constify struct part_type part_type

2023-05-30T17:12:43+00:00

The struct is never modified so it can be const.

Signed-off-by: Thomas Weißschuh 
Link: https://lore.kernel.org/r/20230419-const-partition-v3-2-4e14e48be367@weissschuh.net
Signed-off-by: Jens Axboe