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132 lines
3.3 KiB
132 lines
3.3 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* Copyright (C) 2007 Oracle. All rights reserved. |
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*/ |
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#include <linux/sched.h> |
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#include "ctree.h" |
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#include "disk-io.h" |
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#include "print-tree.h" |
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#include "transaction.h" |
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#include "locking.h" |
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/* |
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* Defrag all the leaves in a given btree. |
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* Read all the leaves and try to get key order to |
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* better reflect disk order |
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*/ |
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int btrfs_defrag_leaves(struct btrfs_trans_handle *trans, |
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struct btrfs_root *root) |
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{ |
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struct btrfs_path *path = NULL; |
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struct btrfs_key key; |
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int ret = 0; |
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int wret; |
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int level; |
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int next_key_ret = 0; |
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u64 last_ret = 0; |
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if (!test_bit(BTRFS_ROOT_SHAREABLE, &root->state)) |
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goto out; |
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path = btrfs_alloc_path(); |
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if (!path) |
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return -ENOMEM; |
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level = btrfs_header_level(root->node); |
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if (level == 0) |
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goto out; |
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if (root->defrag_progress.objectid == 0) { |
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struct extent_buffer *root_node; |
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u32 nritems; |
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root_node = btrfs_lock_root_node(root); |
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nritems = btrfs_header_nritems(root_node); |
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root->defrag_max.objectid = 0; |
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/* from above we know this is not a leaf */ |
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btrfs_node_key_to_cpu(root_node, &root->defrag_max, |
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nritems - 1); |
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btrfs_tree_unlock(root_node); |
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free_extent_buffer(root_node); |
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memset(&key, 0, sizeof(key)); |
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} else { |
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memcpy(&key, &root->defrag_progress, sizeof(key)); |
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} |
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path->keep_locks = 1; |
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ret = btrfs_search_forward(root, &key, path, BTRFS_OLDEST_GENERATION); |
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if (ret < 0) |
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goto out; |
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if (ret > 0) { |
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ret = 0; |
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goto out; |
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} |
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btrfs_release_path(path); |
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/* |
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* We don't need a lock on a leaf. btrfs_realloc_node() will lock all |
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* leafs from path->nodes[1], so set lowest_level to 1 to avoid later |
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* a deadlock (attempting to write lock an already write locked leaf). |
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*/ |
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path->lowest_level = 1; |
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wret = btrfs_search_slot(trans, root, &key, path, 0, 1); |
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if (wret < 0) { |
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ret = wret; |
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goto out; |
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} |
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if (!path->nodes[1]) { |
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ret = 0; |
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goto out; |
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} |
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/* |
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* The node at level 1 must always be locked when our path has |
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* keep_locks set and lowest_level is 1, regardless of the value of |
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* path->slots[1]. |
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*/ |
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BUG_ON(path->locks[1] == 0); |
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ret = btrfs_realloc_node(trans, root, |
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path->nodes[1], 0, |
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&last_ret, |
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&root->defrag_progress); |
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if (ret) { |
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WARN_ON(ret == -EAGAIN); |
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goto out; |
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} |
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/* |
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* Now that we reallocated the node we can find the next key. Note that |
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* btrfs_find_next_key() can release our path and do another search |
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* without COWing, this is because even with path->keep_locks = 1, |
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* btrfs_search_slot() / ctree.c:unlock_up() does not keeps a lock on a |
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* node when path->slots[node_level - 1] does not point to the last |
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* item or a slot beyond the last item (ctree.c:unlock_up()). Therefore |
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* we search for the next key after reallocating our node. |
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*/ |
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path->slots[1] = btrfs_header_nritems(path->nodes[1]); |
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next_key_ret = btrfs_find_next_key(root, path, &key, 1, |
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BTRFS_OLDEST_GENERATION); |
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if (next_key_ret == 0) { |
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memcpy(&root->defrag_progress, &key, sizeof(key)); |
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ret = -EAGAIN; |
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} |
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out: |
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btrfs_free_path(path); |
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if (ret == -EAGAIN) { |
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if (root->defrag_max.objectid > root->defrag_progress.objectid) |
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goto done; |
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if (root->defrag_max.type > root->defrag_progress.type) |
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goto done; |
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if (root->defrag_max.offset > root->defrag_progress.offset) |
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goto done; |
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ret = 0; |
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} |
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done: |
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if (ret != -EAGAIN) |
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memset(&root->defrag_progress, 0, |
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sizeof(root->defrag_progress)); |
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return ret; |
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}
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