Btrfs: Allocator fix variety pack

* Force chunk allocation when find_free_extent has to do a full scan
* Record the max key at the start of defrag so it doesn't run forever
* Block groups might not be contiguous, make a forward search for the
  next block group in extent-tree.c
* Get rid of extra checks for total fs size
* Fix relocate_one_reference to avoid relocating the same file data block
  twice when referenced by an older transaction
* Use the open device count when allocating chunks so that we don't
  try to allocate from devices that don't exist

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

1 files changed, 17 insertions, 0 deletions

diff --git a/fs/btrfs/tree-defrag.c b/fs/btrfs/tree-defrag.c
index c02e2bf2f028..155961c7b4d5 100644
--- a/fs/btrfs/tree-defrag.c
+++ b/fs/btrfs/tree-defrag.c
@@ -198,6 +198,13 @@ int btrfs_defrag_leaves(struct btrfs_trans_handle *trans,
                 goto out;
         }
         if (root->defrag_progress.objectid == 0) {
+                u32 nritems;
+
+                nritems = btrfs_header_nritems(root->node);
+                root->defrag_max.objectid = 0;
+                /* from above we know this is not a leaf */
+                btrfs_node_key_to_cpu(root->node, &root->defrag_max,
+                                      nritems - 1);
                 extent_buffer_get(root->node);
                 ret = btrfs_cow_block(trans, root, root->node, NULL, 0, &tmp);
                 BUG_ON(ret);
@@ -254,6 +261,16 @@ int btrfs_defrag_leaves(struct btrfs_trans_handle *trans,
 out:
         if (path)
                 btrfs_free_path(path);
+        if (ret == -EAGAIN) {
+                if (root->defrag_max.objectid > root->defrag_progress.objectid)
+                        goto done;
+                if (root->defrag_max.type > root->defrag_progress.type)
+                        goto done;
+                if (root->defrag_max.offset > root->defrag_progress.offset)
+                        goto done;
+                ret = 0;
+        }
+done:
         if (ret != -EAGAIN) {
                 memset(&root->defrag_progress, 0,
                        sizeof(root->defrag_progress));