Merge git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable

* git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable:
  Btrfs: check return value of alloc_extent_map()
  Btrfs - Fix memory leak in btrfs_init_new_device()
  btrfs: prevent heap corruption in btrfs_ioctl_space_info()
  Btrfs: Fix balance panic
  Btrfs: don't release pages when we can't clear the uptodate bits
  Btrfs: fix page->private races

fs/btrfs/file.c

@@ -186,6 +186,7 @@ int btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end,
 			split = alloc_extent_map(GFP_NOFS);
 		if (!split2)
 			split2 = alloc_extent_map(GFP_NOFS);
+		BUG_ON(!split || !split2);
 
 		write_lock(&em_tree->lock);
 		em = lookup_extent_mapping(em_tree, start, len);