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>

fs/btrfs/ctree.c

@@ -363,7 +363,7 @@ int btrfs_realloc_node(struct btrfs_trans_handle *trans,
 			other = btrfs_node_blockptr(parent, i - 1);
 			close = close_blocks(blocknr, other, blocksize);
 		}
-		if (close && i < end_slot - 2) {
+		if (!close && i < end_slot - 2) {
 			other = btrfs_node_blockptr(parent, i + 1);
 			close = close_blocks(blocknr, other, blocksize);
 		}

fs/btrfs/ctree.h

@@ -464,6 +464,7 @@ struct btrfs_space_info {
 	u64 bytes_used;
 	u64 bytes_pinned;
 	int full;
+	int force_alloc;
 	struct list_head list;
 };
 
@@ -589,6 +590,7 @@ struct btrfs_root {
 	int ref_cows;
 	int track_dirty;
 	struct btrfs_key defrag_progress;
+	struct btrfs_key defrag_max;
 	int defrag_running;
 	int defrag_level;
 	char *name;

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));

fs/btrfs/volumes.c

@@ -750,10 +750,6 @@ static int btrfs_rm_dev_item(struct btrfs_root *root,
 	if (bdev == fs_devices->latest_bdev)
 		fs_devices->latest_bdev = next_dev->bdev;
 
-	total_bytes = btrfs_super_total_bytes(&root->fs_info->super_copy);
-	btrfs_set_super_total_bytes(&root->fs_info->super_copy,
-				    total_bytes - device->total_bytes);
-
 	total_bytes = btrfs_super_num_devices(&root->fs_info->super_copy);
 	btrfs_set_super_num_devices(&root->fs_info->super_copy,
 				    total_bytes - 1);
@@ -849,6 +845,7 @@ int btrfs_rm_device(struct btrfs_root *root, char *device_path)
 
 	}
 	root->fs_info->fs_devices->num_devices--;
+	root->fs_info->fs_devices->open_devices--;
 
 	ret = btrfs_shrink_device(device, 0);
 	if (ret)
@@ -873,7 +870,6 @@ int btrfs_rm_device(struct btrfs_root *root, char *device_path)
 	if (device->bdev) {
 		/* one close for the device struct or super_block */
 		close_bdev_excl(device->bdev);
-		root->fs_info->fs_devices->open_devices--;
 	}
 	if (bdev) {
 		/* one close for us */
@@ -1450,7 +1446,7 @@ int btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
 		return -ENOSPC;
 
 	if (type & (BTRFS_BLOCK_GROUP_RAID0)) {
-		num_stripes = btrfs_super_num_devices(&info->super_copy);
+		num_stripes = extent_root->fs_info->fs_devices->open_devices;
 		min_stripes = 2;
 	}
 	if (type & (BTRFS_BLOCK_GROUP_DUP)) {
@@ -1459,13 +1455,13 @@ int btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
 	}
 	if (type & (BTRFS_BLOCK_GROUP_RAID1)) {
 		num_stripes = min_t(u64, 2,
-				  btrfs_super_num_devices(&info->super_copy));
+			    extent_root->fs_info->fs_devices->open_devices);
 		if (num_stripes < 2)
 			return -ENOSPC;
 		min_stripes = 2;
 	}
 	if (type & (BTRFS_BLOCK_GROUP_RAID10)) {
-		num_stripes = btrfs_super_num_devices(&info->super_copy);
+		num_stripes = extent_root->fs_info->fs_devices->open_devices;
 		if (num_stripes < 4)
 			return -ENOSPC;
 		num_stripes &= ~(u32)1;