btrfs-progs: better space_cache=v2 support

From: Omar Sandoval <[email protected]>

Hi,

Cover letter from v1:

This series implements some support for space_cache=v2 in btrfs-progs. In particular, this adds support for btrfs check --clear-space-cache v2, proper printing of the free space tree flags for btrfs inspect-internal dump-super, and better documentation.

We'd previously talked about always making btrfs-progs always invalidate the free space tree when doing write operations, but I decided that this should be an action explicitly requested by the user. It'd also be unsafe if using a kernel without the free space tree valid bit support, which is why I didn't implement a btrfs check --invalidate-free-space-cache option. Doing the full clear is always safe.

Still missing is full read-write support, but this should hopefully cover most btrfs-progs usage.

Changes since v1:

- Change unsigned -> unsigned int argument to btrfs_check_fs_compatability() in patch 3
- Remove BUG_ON() in btrfs_del_root() in patch 4
- Return error from btrfs_free_tree_block() in patch 4
- Handle errors from btrfs_free_tree_block() and clean_tree_block() in patch 4
- Add Qu Wenruo's Reviewed-by to patches 3, 4, and 5

Thanks!

Omar Sandoval (6):
btrfs-progs: add the FREE_SPACE_TREE_VALID compat_ro bit definition
btrfs-progs: format FREE_SPACE_TREE{,_VALID} nicely in dump-super
btrfs-progs: add OPEN_CTREE_INVALIDATE_FST flag
btrfs-progs: add btrfs_clear_free_space_tree() from the kernel
btrfs-progs: implement btrfs check --clear-space-cache v2
btrfs-progs: document space_cache=v2 more thoroughly

 Documentation/btrfs-check.asciidoc | 14 +++---
 Documentation/btrfs-man5.asciidoc  | 43 ++++++++++--------
 chunk-recover.c                    |  2 +-
 cmds-check.c                       | 34 ++++++++++----
 cmds-inspect-dump-super.c          | 24 ++++++++++
 ctree.h                            | 19 ++++++++
 disk-io.c                          | 29 +++++++-----
 disk-io.h                          |  9 +++-
 extent-tree.c                      | 11 +++++
 free-space-tree.c                  | 91 ++++++++++++++++++++++++++++++++++++++
 free-space-tree.h                  |  1 +
 root-tree.c                        | 25 +++++++++++
 12 files changed, 258 insertions(+), 44 deletions(-)

2.10.2