Btrfs: add nested locking mode for paths
This patch adds the possibilty to read-lock an extent even if it is already
write-locked from the same thread. btrfs_find_all_roots() needs this
capability.
Signed-off-by: Arne Jansen <sensille@gmx.net>
Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>
diff --git a/fs/btrfs/extent_io.h b/fs/btrfs/extent_io.h
index 7604c30..bc6a042cb 100644
--- a/fs/btrfs/extent_io.h
+++ b/fs/btrfs/extent_io.h
@@ -129,6 +129,7 @@
struct list_head leak_list;
struct rcu_head rcu_head;
atomic_t refs;
+ pid_t lock_owner;
/* count of read lock holders on the extent buffer */
atomic_t write_locks;
@@ -137,6 +138,7 @@
atomic_t blocking_readers;
atomic_t spinning_readers;
atomic_t spinning_writers;
+ int lock_nested;
/* protects write locks */
rwlock_t lock;