diff options
Diffstat (limited to 'fs/btrfs/tree-defrag.c')
| -rw-r--r-- | fs/btrfs/tree-defrag.c | 222 |
1 files changed, 222 insertions, 0 deletions
diff --git a/fs/btrfs/tree-defrag.c b/fs/btrfs/tree-defrag.c new file mode 100644 index 000000000000..15d0a486fb59 --- /dev/null +++ b/fs/btrfs/tree-defrag.c @@ -0,0 +1,222 @@ +/* + * 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" + +static void reada_defrag(struct btrfs_root *root, + struct btrfs_node *node) +{ + int i; + u32 nritems; + u64 blocknr; + int ret; + + nritems = btrfs_header_nritems(&node->header); + for (i = 0; i < nritems; i++) { + blocknr = btrfs_node_blockptr(node, i); + ret = readahead_tree_block(root, blocknr); + if (ret) + break; + } +} + +static int defrag_walk_down(struct btrfs_trans_handle *trans, + struct btrfs_root *root, + struct btrfs_path *path, int *level, + int cache_only) +{ + struct buffer_head *next; + struct buffer_head *cur; + u64 blocknr; + int ret = 0; + + WARN_ON(*level < 0); + WARN_ON(*level >= BTRFS_MAX_LEVEL); + + while(*level > 0) { + WARN_ON(*level < 0); + WARN_ON(*level >= BTRFS_MAX_LEVEL); + cur = path->nodes[*level]; + + if (!cache_only && *level > 1 && path->slots[*level] == 0) + reada_defrag(root, btrfs_buffer_node(cur)); + + if (btrfs_header_level(btrfs_buffer_header(cur)) != *level) + WARN_ON(1); + + if (path->slots[*level] >= + btrfs_header_nritems(btrfs_buffer_header(cur))) + break; + + if (*level == 1) { + ret = btrfs_realloc_node(trans, root, + path->nodes[*level], + cache_only); + break; + } + blocknr = btrfs_node_blockptr(btrfs_buffer_node(cur), + path->slots[*level]); + + if (cache_only) { + next = btrfs_find_tree_block(root, blocknr); + if (!next || !buffer_uptodate(next) || + buffer_locked(next)) { + brelse(next); + path->slots[*level]++; + continue; + } + } else { + next = read_tree_block(root, blocknr); + } + ret = btrfs_cow_block(trans, root, next, path->nodes[*level], + path->slots[*level], &next); + BUG_ON(ret); + ret = btrfs_realloc_node(trans, root, next, cache_only); + BUG_ON(ret); + WARN_ON(*level <= 0); + if (path->nodes[*level-1]) + btrfs_block_release(root, path->nodes[*level-1]); + path->nodes[*level-1] = next; + *level = btrfs_header_level(btrfs_buffer_header(next)); + path->slots[*level] = 0; + } + WARN_ON(*level < 0); + WARN_ON(*level >= BTRFS_MAX_LEVEL); + btrfs_block_release(root, path->nodes[*level]); + path->nodes[*level] = NULL; + *level += 1; + WARN_ON(ret); + return 0; +} + +static int defrag_walk_up(struct btrfs_trans_handle *trans, + struct btrfs_root *root, + struct btrfs_path *path, int *level, + int cache_only) +{ + int i; + int slot; + struct btrfs_node *node; + + for(i = *level; i < BTRFS_MAX_LEVEL - 1 && path->nodes[i]; i++) { + slot = path->slots[i]; + if (slot < btrfs_header_nritems( + btrfs_buffer_header(path->nodes[i])) - 1) { + path->slots[i]++; + *level = i; + node = btrfs_buffer_node(path->nodes[i]); + WARN_ON(i == 0); + btrfs_disk_key_to_cpu(&root->defrag_progress, + &node->ptrs[path->slots[i]].key); + root->defrag_level = i; + return 0; + } else { + btrfs_block_release(root, path->nodes[*level]); + path->nodes[*level] = NULL; + *level = i + 1; + } + } + return 1; +} + +int btrfs_defrag_leaves(struct btrfs_trans_handle *trans, + struct btrfs_root *root, int cache_only) +{ + struct btrfs_path *path = NULL; + struct buffer_head *tmp; + int ret = 0; + int wret; + int level; + int orig_level; + int i; + int num_runs = 0; + + if (root->ref_cows == 0) { + goto out; + } + path = btrfs_alloc_path(); + if (!path) + return -ENOMEM; + + level = btrfs_header_level(btrfs_buffer_header(root->node)); + orig_level = level; + if (level == 0) { + goto out; + } + if (root->defrag_progress.objectid == 0) { + get_bh(root->node); + ret = btrfs_cow_block(trans, root, root->node, NULL, 0, &tmp); + BUG_ON(ret); + ret = btrfs_realloc_node(trans, root, root->node, cache_only); + BUG_ON(ret); + path->nodes[level] = root->node; + path->slots[level] = 0; + } else { + level = root->defrag_level; + path->lowest_level = level; + wret = btrfs_search_slot(trans, root, &root->defrag_progress, + path, 0, 1); + + if (wret < 0) { + ret = wret; + goto out; + } + while(level > 0 && !path->nodes[level]) + level--; + if (!path->nodes[level]) { + ret = 0; + goto out; + } + } + + while(1) { + wret = defrag_walk_down(trans, root, path, &level, cache_only); + if (wret > 0) + break; + if (wret < 0) + ret = wret; + + wret = defrag_walk_up(trans, root, path, &level, cache_only); + if (wret > 0) + break; + if (wret < 0) + ret = wret; + if (num_runs++ > 8) { + ret = -EAGAIN; + break; + } + } + for (i = 0; i <= orig_level; i++) { + if (path->nodes[i]) { + btrfs_block_release(root, path->nodes[i]); + path->nodes[i] = 0; + } + } +out: + if (path) + btrfs_free_path(path); + if (ret != -EAGAIN) { + memset(&root->defrag_progress, 0, + sizeof(root->defrag_progress)); + } + return ret; +} |