tree 1c66dc210f948f79c86786368d2c75b57482875d
parent 33958dc6d38fb4ca7e62273855fcb2db7e616263
author Yan <zheng.yan@oracle.com> 1217449760 -0400
committer Chris Mason <chris.mason@oracle.com> 1222355045 -0400

Btrfs: implement memory reclaim for leaf reference cache

The memory reclaiming issue happens when snapshot exists. In that
case, some cache entries may not be used during old snapshot dropping,
so they will remain in the cache until umount.

The patch adds a field to struct btrfs_leaf_ref to record create time. Besides,
the patch makes all dead roots of a given snapshot linked together in order of
create time. After a old snapshot was completely dropped, we check the dead
root list and remove all cache entries created before the oldest dead root in
the list.

Signed-off-by: Chris Mason <chris.mason@oracle.com>