From 59a55a63c24624c7ad268f12c8f82d142ef6a6d4 Mon Sep 17 00:00:00 2001 From: Christian Brauner Date: Thu, 14 Mar 2024 15:24:13 +0100 Subject: fs,block: get holder during claim Now that we open block devices as files we need to deal with the realities that closing is a deferred operation. An operation on the block device such as e.g., freeze, thaw, or removal that runs concurrently with umount, tries to acquire a stable reference on the holder. The holder might already be gone though. Make that reliable by grabbing a passive reference to the holder during bdev_open() and releasing it during bdev_release(). Fixes: f3a608827d1f ("bdev: open block device as files") # mainline only Reported-by: Christoph Hellwig Link: https://lore.kernel.org/r/ZfEQQ9jZZVes0WCZ@infradead.org Reviewed-by: Jan Kara Reviewed-by: Christoph Hellwig Tested-by: Yi Zhang Reported-by: https://lore.kernel.org/r/CAHj4cs8tbDwKRwfS1=DmooP73ysM__xAb2PQc6XsAmWR+VuYmg@mail.gmail.com Link: https://lore.kernel.org/r/20240315-freibad-annehmbar-ca68c375af91@brauner Signed-off-by: Christian Brauner --- block/bdev.c | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'block') diff --git a/block/bdev.c b/block/bdev.c index e7adaaf1c2192..7a5f611c3d2e3 100644 --- a/block/bdev.c +++ b/block/bdev.c @@ -583,6 +583,9 @@ static void bd_finish_claiming(struct block_device *bdev, void *holder, mutex_unlock(&bdev->bd_holder_lock); bd_clear_claiming(whole, holder); mutex_unlock(&bdev_lock); + + if (hops && hops->get_holder) + hops->get_holder(holder); } /** @@ -605,6 +608,7 @@ EXPORT_SYMBOL(bd_abort_claiming); static void bd_end_claim(struct block_device *bdev, void *holder) { struct block_device *whole = bdev_whole(bdev); + const struct blk_holder_ops *hops = bdev->bd_holder_ops; bool unblock = false; /* @@ -627,6 +631,9 @@ static void bd_end_claim(struct block_device *bdev, void *holder) whole->bd_holder = NULL; mutex_unlock(&bdev_lock); + if (hops && hops->put_holder) + hops->put_holder(holder); + /* * If this was the last claim, remove holder link and unblock evpoll if * it was a write holder. -- cgit 1.2.3-korg