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 --- fs/super.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) (limited to 'fs/super.c') diff --git a/fs/super.c b/fs/super.c index ee05ab6b37e7..71d9779c42b1 100644 --- a/fs/super.c +++ b/fs/super.c @@ -1515,11 +1515,29 @@ static int fs_bdev_thaw(struct block_device *bdev) return error; } +static void fs_bdev_super_get(void *data) +{ + struct super_block *sb = data; + + spin_lock(&sb_lock); + sb->s_count++; + spin_unlock(&sb_lock); +} + +static void fs_bdev_super_put(void *data) +{ + struct super_block *sb = data; + + put_super(sb); +} + const struct blk_holder_ops fs_holder_ops = { .mark_dead = fs_bdev_mark_dead, .sync = fs_bdev_sync, .freeze = fs_bdev_freeze, .thaw = fs_bdev_thaw, + .get_holder = fs_bdev_super_get, + .put_holder = fs_bdev_super_put, }; EXPORT_SYMBOL_GPL(fs_holder_ops); -- cgit