Btrfs: extent_map and data=ordered fixes for space balancing

* Add an EXTENT_BOUNDARY state bit to keep the writepage code
from merging data extents that are in the process of being
relocated.  This allows us to do accounting for them properly.

* The balancing code relocates data extents indepdent of the underlying
inode.  The extent_map code was modified to properly account for
things moving around (invalidating extent_map caches in the inode).

* Don't take the drop_mutex in the create_subvol ioctl.  It isn't
required.

* Fix walking of the ordered extent list to avoid races with sys_unlink

* Change the lock ordering rules.  Transaction start goes outside
the drop_mutex.  This allows btrfs_commit_transaction to directly
drop the relocation trees.

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

1 files changed, 4 insertions, 0 deletions

diff --git a/fs/btrfs/inode-map.c b/fs/btrfs/inode-map.c
index cd6171c2da42..80038c5ef7cf 100644
--- a/fs/btrfs/inode-map.c
+++ b/fs/btrfs/inode-map.c
@@ -117,10 +117,14 @@ int btrfs_find_free_objectid(struct btrfs_trans_handle *trans,
                                         *objectid = last_ino;
                                         goto found;
                                 }
+                        } else if (key.objectid > search_start) {
+                                *objectid = search_start;
+                                goto found;
                         }
                 }
                 if (key.objectid >= BTRFS_LAST_FREE_OBJECTID)
                         break;
+
                 start_found = 1;
                 last_ino = key.objectid + 1;
                 path->slots[0]++;