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>
This commit is contained in:
Arne Jansen
2011-09-13 10:55:48 +02:00
committed by Jan Schmidt
parent eebe063b7f
commit 5b25f70f42
3 changed files with 54 additions and 2 deletions

View File

@@ -3571,6 +3571,7 @@ static struct extent_buffer *__alloc_extent_buffer(struct extent_io_tree *tree,
atomic_set(&eb->blocking_writers, 0);
atomic_set(&eb->spinning_readers, 0);
atomic_set(&eb->spinning_writers, 0);
eb->lock_nested = 0;
init_waitqueue_head(&eb->write_lock_wq);
init_waitqueue_head(&eb->read_lock_wq);