Commit 44abfa6a authored by Yu Kuai's avatar Yu Kuai Committed by Song Liu
Browse files

md/md-bitmap: hold 'reconfig_mutex' in backlog_store() 



Several reasons why 'reconfig_mutex' should be held:

1) rdev_for_each() is not safe to be called without the lock, because
   rdev can be removed concurrently.
2) mddev_destroy_serial_pool() and mddev_create_serial_pool() should not
   be called concurrently.
3) mddev_suspend() from mddev_destroy/create_serial_pool() should be
   protected by the lock.

Fixes: 10c92fca ("md-bitmap: create and destroy wb_info_pool with the change of backlog")
Signed-off-by: default avatarYu Kuai <yukuai3@huawei.com>
Link: https://lore.kernel.org/r/20230706083727.608914-3-yukuai1@huaweicloud.com


Signed-off-by: default avatarSong Liu <song@kernel.org>
parent b4d12964

drivers/md/md-bitmap.c

+7 −0
Original line number Diff line number Diff line
@@ -2546,6 +2546,10 @@ backlog_store(struct mddev *mddev, const char *buf, size_t len) 
	if (backlog > COUNTER_MAX)

		return -EINVAL;



	rv = mddev_lock(mddev);

	if (rv)

		return rv;



	/*

	 * Without write mostly device, it doesn't make sense to set

	 * backlog for max_write_behind.
@@ -2559,6 +2563,7 @@ backlog_store(struct mddev *mddev, const char *buf, size_t len) 
	if (!has_write_mostly) {

		pr_warn_ratelimited("%s: can't set backlog, no write mostly device available\n",

				    mdname(mddev));

		mddev_unlock(mddev);

		return -EINVAL;

	}
@@ -2574,6 +2579,8 @@ backlog_store(struct mddev *mddev, const char *buf, size_t len) 
	}

	if (old_mwb != backlog)

		md_bitmap_update_sb(mddev->bitmap);



	mddev_unlock(mddev);

	return len;

}