Btrfs: use rcu to protect device->name

2012-06-15T01:29:16+00:00

Al pointed out that we can just toss out the old name on a device and add a new one arbitrarily, so anybody who uses device->name in printk could possibly use free'd memory. Instead of adding locking around all of this he suggested doing it with RCU, so I've introduced a struct rcu_string that does just that and have gone through and protected all accesses to device->name that aren't under the uuid_mutex with rcu_read_lock(). This protects us and I will use it for dealing with removing the device that we used to mount the file system in a later patch. Thanks, Reviewed-by: David Sterba Signed-off-by: Josef Bacik

kernel/linux.git/fs/btrfs/rcu-string.h, branch linux-4.4.y

Btrfs: use rcu to protect device->name