Btrfs: Add btree locking to the tree defragmentation code
The online btree defragger is simplified and rewritten to use standard btree searches instead of a walk up / down mechanism. Signed-off-by: Chris Mason <chris.mason@oracle.com>
This commit is contained in:
Chris Mason
Родитель
a74a4b97b6
Коммит
e7a84565bc
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@ -354,7 +354,6 @@ int btrfs_realloc_node(struct btrfs_trans_handle *trans,
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struct btrfs_key *progress)
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{
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struct extent_buffer *cur;
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struct extent_buffer *tmp;
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u64 blocknr;
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u64 gen;
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u64 search_start = *last_ret;
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@ -370,9 +369,6 @@ int btrfs_realloc_node(struct btrfs_trans_handle *trans,
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int progress_passed = 0;
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struct btrfs_disk_key disk_key;
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/* FIXME this code needs locking */
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return 0;
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parent_level = btrfs_header_level(parent);
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if (cache_only && parent_level != 1)
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return 0;
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@ -454,20 +450,23 @@ int btrfs_realloc_node(struct btrfs_trans_handle *trans,
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if (search_start == 0)
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search_start = last_block;
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btrfs_tree_lock(cur);
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err = __btrfs_cow_block(trans, root, cur, parent, i,
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&tmp, search_start,
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&cur, search_start,
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min(16 * blocksize,
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(end_slot - i) * blocksize));
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if (err) {
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btrfs_tree_unlock(cur);
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free_extent_buffer(cur);
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break;
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}
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search_start = tmp->start;
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last_block = tmp->start;
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search_start = cur->start;
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last_block = cur->start;
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*last_ret = search_start;
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if (parent_level == 1)
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btrfs_clear_buffer_defrag(tmp);
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free_extent_buffer(tmp);
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btrfs_clear_buffer_defrag(cur);
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btrfs_tree_unlock(cur);
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free_extent_buffer(cur);
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}
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if (parent->map_token) {
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unmap_extent_buffer(parent, parent->map_token,
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@ -2970,6 +2969,35 @@ int btrfs_prev_leaf(struct btrfs_root *root, struct btrfs_path *path)
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return 1;
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}
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int btrfs_find_next_key(struct btrfs_root *root, struct btrfs_path *path,
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struct btrfs_key *key, int lowest_level)
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{
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int level = lowest_level;
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int slot;
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struct extent_buffer *c;
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while(level < BTRFS_MAX_LEVEL) {
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if (!path->nodes[level])
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return 1;
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slot = path->slots[level] + 1;
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c = path->nodes[level];
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if (slot >= btrfs_header_nritems(c)) {
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level++;
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if (level == BTRFS_MAX_LEVEL) {
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return 1;
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}
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continue;
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}
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if (level == 0)
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btrfs_item_key_to_cpu(c, key, slot);
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else
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btrfs_node_key_to_cpu(c, key, slot);
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return 0;
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}
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return 1;
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}
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/*
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* search the tree again to find a leaf with greater keys
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* returns 0 if it found something or 1 if there are no greater leaves.
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@ -1411,6 +1411,8 @@ int btrfs_previous_item(struct btrfs_root *root,
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struct extent_buffer *btrfs_root_node(struct btrfs_root *root);
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struct extent_buffer *btrfs_lock_root_node(struct btrfs_root *root);
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int btrfs_find_next_key(struct btrfs_root *root, struct btrfs_path *path,
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struct btrfs_key *key, int lowest_level);
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int btrfs_cow_block(struct btrfs_trans_handle *trans,
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struct btrfs_root *root, struct extent_buffer *buf,
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@ -2201,6 +2201,7 @@ int drop_snap_lookup_refcount(struct btrfs_root *root, u64 start, u64 len,
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{
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mutex_unlock(&root->fs_info->alloc_mutex);
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lookup_extent_ref(NULL, root, start, len, refs);
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cond_resched();
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mutex_lock(&root->fs_info->alloc_mutex);
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return lookup_extent_ref(NULL, root, start, len, refs);
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}
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@ -2280,6 +2281,7 @@ static int noinline walk_down_tree(struct btrfs_trans_handle *trans,
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next = read_tree_block(root, bytenr, blocksize,
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ptr_gen);
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cond_resched();
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mutex_lock(&root->fs_info->alloc_mutex);
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/* we've dropped the lock, double check */
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@ -2329,6 +2331,7 @@ out:
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*level += 1;
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BUG_ON(ret);
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mutex_unlock(&root->fs_info->alloc_mutex);
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cond_resched();
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return 0;
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}
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@ -2448,6 +2451,10 @@ int btrfs_drop_snapshot(struct btrfs_trans_handle *trans, struct btrfs_root
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break;
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if (wret < 0)
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ret = wret;
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if (trans->transaction->in_commit) {
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ret = -EAGAIN;
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break;
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}
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}
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for (i = 0; i <= orig_level; i++) {
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if (path->nodes[i]) {
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@ -21,167 +21,26 @@
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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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static void reada_defrag(struct btrfs_root *root,
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struct extent_buffer *node)
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{
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int i;
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u32 nritems;
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u64 bytenr;
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u64 gen;
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u32 blocksize;
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int ret;
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blocksize = btrfs_level_size(root, btrfs_header_level(node) - 1);
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nritems = btrfs_header_nritems(node);
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for (i = 0; i < nritems; i++) {
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bytenr = btrfs_node_blockptr(node, i);
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gen = btrfs_node_ptr_generation(node, i);
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ret = readahead_tree_block(root, bytenr, blocksize, gen);
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if (ret)
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break;
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}
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}
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static int defrag_walk_down(struct btrfs_trans_handle *trans,
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struct btrfs_root *root,
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struct btrfs_path *path, int *level,
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int cache_only, u64 *last_ret)
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{
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struct extent_buffer *next;
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struct extent_buffer *cur;
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u64 bytenr;
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u64 ptr_gen;
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int ret = 0;
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int is_extent = 0;
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WARN_ON(*level < 0);
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WARN_ON(*level >= BTRFS_MAX_LEVEL);
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if (root->fs_info->extent_root == root)
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is_extent = 1;
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if (*level == 1 && cache_only && path->nodes[1] &&
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!btrfs_buffer_defrag(path->nodes[1])) {
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goto out;
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}
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while(*level > 0) {
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WARN_ON(*level < 0);
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WARN_ON(*level >= BTRFS_MAX_LEVEL);
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cur = path->nodes[*level];
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if (!cache_only && *level > 1 && path->slots[*level] == 0)
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reada_defrag(root, cur);
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if (btrfs_header_level(cur) != *level)
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WARN_ON(1);
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if (path->slots[*level] >=
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btrfs_header_nritems(cur))
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break;
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if (*level == 1) {
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WARN_ON(btrfs_header_generation(path->nodes[*level]) !=
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trans->transid);
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ret = btrfs_realloc_node(trans, root,
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path->nodes[*level],
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path->slots[*level],
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cache_only, last_ret,
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&root->defrag_progress);
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if (is_extent)
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btrfs_extent_post_op(trans, root);
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break;
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}
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bytenr = btrfs_node_blockptr(cur, path->slots[*level]);
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ptr_gen = btrfs_node_ptr_generation(cur, path->slots[*level]);
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if (cache_only) {
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next = btrfs_find_tree_block(root, bytenr,
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btrfs_level_size(root, *level - 1));
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if (!next || !btrfs_buffer_uptodate(next, ptr_gen) ||
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!btrfs_buffer_defrag(next)) {
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free_extent_buffer(next);
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path->slots[*level]++;
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continue;
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}
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} else {
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next = read_tree_block(root, bytenr,
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btrfs_level_size(root, *level - 1),
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ptr_gen);
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}
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ret = btrfs_cow_block(trans, root, next, path->nodes[*level],
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path->slots[*level], &next);
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BUG_ON(ret);
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if (is_extent)
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btrfs_extent_post_op(trans, root);
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WARN_ON(*level <= 0);
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if (path->nodes[*level-1])
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free_extent_buffer(path->nodes[*level-1]);
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path->nodes[*level-1] = next;
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*level = btrfs_header_level(next);
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path->slots[*level] = 0;
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}
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WARN_ON(*level < 0);
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WARN_ON(*level >= BTRFS_MAX_LEVEL);
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btrfs_clear_buffer_defrag(path->nodes[*level]);
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out:
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free_extent_buffer(path->nodes[*level]);
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path->nodes[*level] = NULL;
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*level += 1;
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WARN_ON(ret && ret != -EAGAIN);
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return ret;
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}
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static int defrag_walk_up(struct btrfs_trans_handle *trans,
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struct btrfs_root *root,
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struct btrfs_path *path, int *level,
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int cache_only)
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{
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int i;
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int slot;
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struct extent_buffer *node;
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for(i = *level; i < BTRFS_MAX_LEVEL - 1 && path->nodes[i]; i++) {
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slot = path->slots[i];
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if (slot < btrfs_header_nritems(path->nodes[i]) - 1) {
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path->slots[i]++;
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*level = i;
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node = path->nodes[i];
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WARN_ON(i == 0);
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btrfs_node_key_to_cpu(node, &root->defrag_progress,
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path->slots[i]);
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root->defrag_level = i;
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return 0;
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} else {
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btrfs_clear_buffer_defrag(path->nodes[*level]);
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free_extent_buffer(path->nodes[*level]);
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path->nodes[*level] = NULL;
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*level = i + 1;
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}
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}
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return 1;
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}
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#include "locking.h"
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int btrfs_defrag_leaves(struct btrfs_trans_handle *trans,
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struct btrfs_root *root, int cache_only)
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{
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struct btrfs_path *path = NULL;
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struct extent_buffer *tmp;
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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 orig_level;
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int i;
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int is_extent = 0;
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int next_key_ret = 0;
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u64 last_ret = 0;
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if (root->fs_info->extent_root == root)
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if (root->fs_info->extent_root == root) {
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mutex_lock(&root->fs_info->alloc_mutex);
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is_extent = 1;
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goto out;
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}
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if (root->ref_cows == 0 && !is_extent)
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goto out;
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@ -200,67 +59,63 @@ int btrfs_defrag_leaves(struct btrfs_trans_handle *trans,
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goto out;
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}
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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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nritems = btrfs_header_nritems(root->node);
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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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btrfs_node_key_to_cpu(root_node, &root->defrag_max,
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nritems - 1);
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extent_buffer_get(root->node);
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ret = btrfs_cow_block(trans, root, root->node, NULL, 0, &tmp);
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BUG_ON(ret);
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path->nodes[level] = root->node;
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path->slots[level] = 0;
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if (is_extent)
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btrfs_extent_post_op(trans, root);
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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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level = root->defrag_level;
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path->lowest_level = level;
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wret = btrfs_search_slot(trans, root, &root->defrag_progress,
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path, 0, 1);
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memcpy(&key, &root->defrag_progress, sizeof(key));
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}
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if (is_extent)
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btrfs_extent_post_op(trans, root);
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path->lowest_level = 1;
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path->keep_locks = 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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while(level > 0 && !path->nodes[level])
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level--;
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if (!path->nodes[level]) {
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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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while(1) {
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wret = defrag_walk_down(trans, root, path, &level, cache_only,
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&last_ret);
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if (wret > 0)
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break;
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if (wret < 0)
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ret = wret;
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wret = defrag_walk_up(trans, root, path, &level, cache_only);
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if (wret > 0)
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break;
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if (wret < 0)
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ret = wret;
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else
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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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ret = btrfs_realloc_node(trans, root,
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path->nodes[1], 0,
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cache_only, &last_ret,
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&root->defrag_progress);
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WARN_ON(ret && ret != -EAGAIN);
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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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break;
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}
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for (i = 0; i <= orig_level; i++) {
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for (i = 1; i < BTRFS_MAX_LEVEL; i++) {
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if (path->locks[i]) {
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btrfs_tree_unlock(path->nodes[i]);
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path->locks[i] = 0;
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}
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if (path->nodes[i]) {
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free_extent_buffer(path->nodes[i]);
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path->nodes[i] = NULL;
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}
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}
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if (is_extent)
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btrfs_extent_post_op(trans, root);
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out:
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if (is_extent)
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mutex_unlock(&root->fs_info->alloc_mutex);
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if (path)
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btrfs_free_path(path);
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if (ret == -EAGAIN) {
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