Line data    Source code

       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             : /*
      27             :  * Defrag all the leaves in a given btree.
      28             :  * Read all the leaves and try to get key order to
      29             :  * better reflect disk order
      30             :  */
      31             : 
      32           4 : int btrfs_defrag_leaves(struct btrfs_trans_handle *trans,
      33             :                         struct btrfs_root *root)
      34             : {
      35             :         struct btrfs_path *path = NULL;
      36             :         struct btrfs_key key;
      37             :         int ret = 0;
      38             :         int wret;
      39             :         int level;
      40             :         int next_key_ret = 0;
      41           4 :         u64 last_ret = 0;
      42             :         u64 min_trans = 0;
      43             : 
      44           4 :         if (root->fs_info->extent_root == root) {
      45             :                 /*
      46             :                  * there's recursion here right now in the tree locking,
      47             :                  * we can't defrag the extent root without deadlock
      48             :                  */
      49             :                 goto out;
      50             :         }
      51             : 
      52           2 :         if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
      53             :                 goto out;
      54             : 
      55           2 :         if (btrfs_test_opt(root, SSD))
      56             :                 goto out;
      57             : 
      58           2 :         path = btrfs_alloc_path();
      59           2 :         if (!path)
      60             :                 return -ENOMEM;
      61             : 
      62           2 :         level = btrfs_header_level(root->node);
      63             : 
      64           2 :         if (level == 0)
      65             :                 goto out;
      66             : 
      67           0 :         if (root->defrag_progress.objectid == 0) {
      68           0 :                 struct extent_buffer *root_node;
      69             :                 u32 nritems;
      70             : 
      71           0 :                 root_node = btrfs_lock_root_node(root);
      72             :                 btrfs_set_lock_blocking(root_node);
      73             :                 nritems = btrfs_header_nritems(root_node);
      74           0 :                 root->defrag_max.objectid = 0;
      75             :                 /* from above we know this is not a leaf */
      76           0 :                 btrfs_node_key_to_cpu(root_node, &root->defrag_max,
      77           0 :                                       nritems - 1);
      78           0 :                 btrfs_tree_unlock(root_node);
      79           0 :                 free_extent_buffer(root_node);
      80           0 :                 memset(&key, 0, sizeof(key));
      81             :         } else {
      82           0 :                 memcpy(&key, &root->defrag_progress, sizeof(key));
      83             :         }
      84             : 
      85           0 :         path->keep_locks = 1;
      86             : 
      87           0 :         ret = btrfs_search_forward(root, &key, path, min_trans);
      88           0 :         if (ret < 0)
      89             :                 goto out;
      90           0 :         if (ret > 0) {
      91             :                 ret = 0;
      92             :                 goto out;
      93             :         }
      94           0 :         btrfs_release_path(path);
      95           0 :         wret = btrfs_search_slot(trans, root, &key, path, 0, 1);
      96             : 
      97           0 :         if (wret < 0) {
      98             :                 ret = wret;
      99             :                 goto out;
     100             :         }
     101           0 :         if (!path->nodes[1]) {
     102             :                 ret = 0;
     103             :                 goto out;
     104             :         }
     105           0 :         path->slots[1] = btrfs_header_nritems(path->nodes[1]);
     106           0 :         next_key_ret = btrfs_find_next_key(root, path, &key, 1,
     107             :                                            min_trans);
     108           0 :         ret = btrfs_realloc_node(trans, root,
     109             :                                  path->nodes[1], 0,
     110             :                                  &last_ret,
     111             :                                  &root->defrag_progress);
     112           0 :         if (ret) {
     113           0 :                 WARN_ON(ret == -EAGAIN);
     114             :                 goto out;
     115             :         }
     116           0 :         if (next_key_ret == 0) {
     117           0 :                 memcpy(&root->defrag_progress, &key, sizeof(key));
     118             :                 ret = -EAGAIN;
     119             :         }
     120             : out:
     121           4 :         if (path)
     122           2 :                 btrfs_free_path(path);
     123           4 :         if (ret == -EAGAIN) {
     124           0 :                 if (root->defrag_max.objectid > root->defrag_progress.objectid)
     125             :                         goto done;
     126           0 :                 if (root->defrag_max.type > root->defrag_progress.type)
     127             :                         goto done;
     128           0 :                 if (root->defrag_max.offset > root->defrag_progress.offset)
     129             :                         goto done;
     130             :                 ret = 0;
     131             :         }
     132             : done:
     133           4 :         if (ret != -EAGAIN) {
     134           4 :                 memset(&root->defrag_progress, 0,
     135             :                        sizeof(root->defrag_progress));
     136           4 :                 root->defrag_trans_start = trans->transid;
     137             :         }
     138           4 :         return ret;
     139             : }