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 --- include/linux/blkdev.h | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'include/linux/blkdev.h') diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index f9b87c39cab0..c3e8f7cf96be 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -1505,6 +1505,16 @@ struct blk_holder_ops { * Thaw the file system mounted on the block device. */ int (*thaw)(struct block_device *bdev); + + /* + * If needed, get a reference to the holder. + */ + void (*get_holder)(void *holder); + + /* + * Release the holder. + */ + void (*put_holder)(void *holder); }; /* -- cgit v1.2.3