SAFE public projects git trees. - safe/jmp/linux-2.6/blob - fs/btrfs/tree-defrag.c

   1 /*
   2  * Copyright (C) 2007 Oracle.  All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public
   6  * License v2 as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public
  14  * License along with this program; if not, write to the
  15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16  * Boston, MA 021110-1307, USA.
  17  */
  18
  19 #include <linux/sched.h>
  20 #include "ctree.h"
  21 #include "disk-io.h"
  22 #include "print-tree.h"
  23 #include "transaction.h"
  24 #include "locking.h"
  25
  26 int btrfs_defrag_leaves(struct btrfs_trans_handle *trans,
  27                         struct btrfs_root *root, int cache_only)
  28 {
  29         struct btrfs_path *path = NULL;
  30         struct btrfs_key key;
  31         int ret = 0;
  32         int wret;
  33         int level;
  34         int orig_level;
  35         int i;
  36         int is_extent = 0;
  37         int next_key_ret = 0;
  38         u64 last_ret = 0;
  39
  40         if (root->fs_info->extent_root == root) {
  41                 mutex_lock(&root->fs_info->alloc_mutex);
  42                 is_extent = 1;
  43         }
  44
  45         if (root->ref_cows == 0 && !is_extent)
  46                 goto out;
  47
  48         if (btrfs_test_opt(root, SSD))
  49                 goto out;
  50
  51         path = btrfs_alloc_path();
  52         if (!path)
  53                 return -ENOMEM;
  54
  55         level = btrfs_header_level(root->node);
  56         orig_level = level;
  57
  58         if (level == 0) {
  59                 goto out;
  60         }
  61         if (root->defrag_progress.objectid == 0) {
  62                 struct extent_buffer *root_node;
  63                 u32 nritems;
  64
  65                 root_node = btrfs_lock_root_node(root);
  66                 nritems = btrfs_header_nritems(root_node);
  67                 root->defrag_max.objectid = 0;
  68                 /* from above we know this is not a leaf */
  69                 btrfs_node_key_to_cpu(root_node, &root->defrag_max,
  70                                       nritems - 1);
  71                 btrfs_tree_unlock(root_node);
  72                 free_extent_buffer(root_node);
  73                 memset(&key, 0, sizeof(key));
  74         } else {
  75                 memcpy(&key, &root->defrag_progress, sizeof(key));
  76         }
  77
  78         path->lowest_level = 1;
  79         path->keep_locks = 1;
  80         wret = btrfs_search_slot(trans, root, &key, path, 0, 1);
  81
  82         if (wret < 0) {
  83                 ret = wret;
  84                 goto out;
  85         }
  86         if (!path->nodes[1]) {
  87                 ret = 0;
  88                 goto out;
  89         }
  90         path->slots[1] = btrfs_header_nritems(path->nodes[1]);
  91         next_key_ret = btrfs_find_next_key(root, path, &key, 1);
  92         ret = btrfs_realloc_node(trans, root,
  93                                  path->nodes[1], 0,
  94                                  cache_only, &last_ret,
  95                                  &root->defrag_progress);
  96         WARN_ON(ret && ret != -EAGAIN);
  97         if (next_key_ret == 0) {
  98                 memcpy(&root->defrag_progress, &key, sizeof(key));
  99                 ret = -EAGAIN;
 100         }
 101
 102         for (i = 1; i < BTRFS_MAX_LEVEL; i++) {
 103                 if (path->locks[i]) {
 104                         btrfs_tree_unlock(path->nodes[i]);
 105                         path->locks[i] = 0;
 106                 }
 107                 if (path->nodes[i]) {
 108                         free_extent_buffer(path->nodes[i]);
 109                         path->nodes[i] = NULL;
 110                 }
 111         }
 112         if (is_extent)
 113                 btrfs_extent_post_op(trans, root);
 114
 115 out:
 116         if (is_extent)
 117                 mutex_unlock(&root->fs_info->alloc_mutex);
 118
 119         if (path)
 120                 btrfs_free_path(path);
 121         if (ret == -EAGAIN) {
 122                 if (root->defrag_max.objectid > root->defrag_progress.objectid)
 123                         goto done;
 124                 if (root->defrag_max.type > root->defrag_progress.type)
 125                         goto done;
 126                 if (root->defrag_max.offset > root->defrag_progress.offset)
 127                         goto done;
 128                 ret = 0;
 129         }
 130 done:
 131         if (ret != -EAGAIN) {
 132                 memset(&root->defrag_progress, 0,
 133                        sizeof(root->defrag_progress));
 134         }
 135         return ret;
 136 }