Btrfs: do not hold the write_lock on the extent tree while logging
Dave Sterba pointed out a sleeping while atomic bug while doing fsync. This
is because I'm an idiot and didn't realize that rwlock's were spin locks, so
we've been holding this thing while doing allocations and such which is not
good. This patch fixes this by dropping the write lock before we do
anything heavy and re-acquire it when it is done. We also need to take a
ref on the em's in case their corresponding pages are evicted and mark them
as being logged so that releasepage does not remove them and doesn't remove
them from our local list. Thanks,
Reported-by: Dave Sterba <dave@jikos.cz>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
diff --git a/fs/btrfs/extent_map.h b/fs/btrfs/extent_map.h
index 8e6294b..6792255 100644
--- a/fs/btrfs/extent_map.h
+++ b/fs/btrfs/extent_map.h
@@ -13,6 +13,7 @@
#define EXTENT_FLAG_COMPRESSED 1
#define EXTENT_FLAG_VACANCY 2 /* no file extent item found */
#define EXTENT_FLAG_PREALLOC 3 /* pre-allocated extent */
+#define EXTENT_FLAG_LOGGING 4 /* Logging this extent */
struct extent_map {
struct rb_node rb_node;