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dm: restore synchronous close of device mapper block device

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'dmsetup remove' and 'dmsetup remove_all' require synchronous bdev
release. Otherwise dm_lock_for_deletion() may return -EBUSY if the open
count is > 0, because the open count is dropped in dm_blk_close()
which occurs after fput() completes.

So if dm_blk_close() is delayed because of asynchronous fput(), this
device mapper device is skipped during remove, which is a regression.

Fix the issue by using __fput_sync().

Also, DM device removal has long supported being made asynchronous by
setting the DMF_DEFERRED_REMOVE flag on the DM device. So leverage
using async fput() in close_table_device() if DMF_DEFERRED_REMOVE flag
is set.

Reported-by: Zhong Changhui <czhong@redhat.com>
Fixes: a28d893eb3 ("md: port block device access to file")
Suggested-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
[snitzer: editted commit header, use fput() if DMF_DEFERRED_REMOVE set]
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
This commit is contained in:
Ming Lei 2024-04-16 08:56:33 +08:00 committed by Mike Snitzer
parent f141dde5dc
commit 48ef0ba12e
1 changed files with 8 additions and 2 deletions
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10
drivers/md/dm.c
View file

@ -765,7 +765,7 @@ static struct table_device *open_table_device(struct mapped_device *md,
return td;
out_blkdev_put:
fput(bdev_file);
__fput_sync(bdev_file);
out_free_td:
kfree(td);
return ERR_PTR(r);
@ -778,7 +778,13 @@ static void close_table_device(struct table_device *td, struct mapped_device *md
{
if (md->disk->slave_dir)
bd_unlink_disk_holder(td->dm_dev.bdev, md->disk);
fput(td->dm_dev.bdev_file);
/* Leverage async fput() if DMF_DEFERRED_REMOVE set */
if (unlikely(test_bit(DMF_DEFERRED_REMOVE, &md->flags)))
fput(td->dm_dev.bdev_file);
else
__fput_sync(td->dm_dev.bdev_file);
put_dax(td->dm_dev.dax_dev);
list_del(&td->list);
kfree(td);