Merge branch 'for-linus-unmerged' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable

* 'for-linus-unmerged' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable: (45 commits)
  Btrfs: fix __btrfs_map_block on 32 bit machines
  btrfs: fix possible deadlock by clearing __GFP_FS flag
  btrfs: check link counter overflow in link(2)
  btrfs: don't mess with i_nlink of unlocked inode in rename()
  Btrfs: check return value of btrfs_alloc_path()
  Btrfs: fix OOPS of empty filesystem after balance
  Btrfs: fix memory leak of empty filesystem after balance
  Btrfs: fix return value of setflags ioctl
  Btrfs: fix uncheck memory allocations
  btrfs: make inode ref log recovery faster
  Btrfs: add btrfs_trim_fs() to handle FITRIM
  Btrfs: adjust btrfs_discard_extent() return errors and trimmed bytes
  Btrfs: make btrfs_map_block() return entire free extent for each device of RAID0/1/10/DUP
  Btrfs: make update_reserved_bytes() public
  btrfs: return EXDEV when linking from different subvolumes
  Btrfs: Per file/directory controls for COW and compression
  Btrfs: add datacow flag in inode flag
  btrfs: use GFP_NOFS instead of GFP_KERNEL
  Btrfs: check return value of read_tree_block()
  btrfs: properly access unaligned checksum buffer
  ...

Fix up trivial conflicts in fs/btrfs/volumes.c due to plug removal in
the block layer.

fs/btrfs/extent_io.c

@@ -2192,6 +2192,8 @@ static int __extent_writepage(struct page *page, struct writeback_control *wbc,
 	else
 		write_flags = WRITE;
 
+	trace___extent_writepage(page, inode, wbc);
+
 	WARN_ON(!PageLocked(page));
 	pg_offset = i_size & (PAGE_CACHE_SIZE - 1);
 	if (page->index > end_index ||
@@ -3690,6 +3692,7 @@ int map_private_extent_buffer(struct extent_buffer *eb, unsigned long start,
 		       "wanted %lu %lu\n", (unsigned long long)eb->start,
 		       eb->len, start, min_len);
 		WARN_ON(1);
+		return -EINVAL;
 	}
 
 	p = extent_buffer_page(eb, i);