Add the rt linux 4.1.3-rt3 as base

[kvmfornfv.git] / kernel / fs / btrfs / tree-defrag.c

diff --git a/kernel/fs/btrfs/tree-defrag.c b/kernel/fs/btrfs/tree-defrag.c
new file mode 100644 (file)
index 0000000..a63719c
--- /dev/null
+++ b/kernel/fs/btrfs/tree-defrag.c
@@ -0,0 +1,139 @@
+/*
+ * Copyright (C) 2007 Oracle.  All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License v2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 021110-1307, USA.
+ */
+
+#include <linux/sched.h>
+#include "ctree.h"
+#include "disk-io.h"
+#include "print-tree.h"
+#include "transaction.h"
+#include "locking.h"
+
+/*
+ * Defrag all the leaves in a given btree.
+ * Read all the leaves and try to get key order to
+ * better reflect disk order
+ */
+
+int btrfs_defrag_leaves(struct btrfs_trans_handle *trans,
+                       struct btrfs_root *root)
+{
+       struct btrfs_path *path = NULL;
+       struct btrfs_key key;
+       int ret = 0;
+       int wret;
+       int level;
+       int next_key_ret = 0;
+       u64 last_ret = 0;
+       u64 min_trans = 0;
+
+       if (root->fs_info->extent_root == root) {
+               /*
+                * there's recursion here right now in the tree locking,
+                * we can't defrag the extent root without deadlock
+                */
+               goto out;
+       }
+
+       if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
+               goto out;
+
+       if (btrfs_test_opt(root, SSD))
+               goto out;
+
+       path = btrfs_alloc_path();
+       if (!path)
+               return -ENOMEM;
+
+       level = btrfs_header_level(root->node);
+
+       if (level == 0)
+               goto out;
+
+       if (root->defrag_progress.objectid == 0) {
+               struct extent_buffer *root_node;
+               u32 nritems;
+
+               root_node = btrfs_lock_root_node(root);
+               btrfs_set_lock_blocking(root_node);
+               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);
+               btrfs_tree_unlock(root_node);
+               free_extent_buffer(root_node);
+               memset(&key, 0, sizeof(key));
+       } else {
+               memcpy(&key, &root->defrag_progress, sizeof(key));
+       }
+
+       path->keep_locks = 1;
+
+       ret = btrfs_search_forward(root, &key, path, min_trans);
+       if (ret < 0)
+               goto out;
+       if (ret > 0) {
+               ret = 0;
+               goto out;
+       }
+       btrfs_release_path(path);
+       wret = btrfs_search_slot(trans, root, &key, path, 0, 1);
+
+       if (wret < 0) {
+               ret = wret;
+               goto out;
+       }
+       if (!path->nodes[1]) {
+               ret = 0;
+               goto out;
+       }
+       path->slots[1] = btrfs_header_nritems(path->nodes[1]);
+       next_key_ret = btrfs_find_next_key(root, path, &key, 1,
+                                          min_trans);
+       ret = btrfs_realloc_node(trans, root,
+                                path->nodes[1], 0,
+                                &last_ret,
+                                &root->defrag_progress);
+       if (ret) {
+               WARN_ON(ret == -EAGAIN);
+               goto out;
+       }
+       if (next_key_ret == 0) {
+               memcpy(&root->defrag_progress, &key, sizeof(key));
+               ret = -EAGAIN;
+       }
+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));
+               root->defrag_trans_start = trans->transid;
+       }
+       return ret;
+}