Btrfs: Add run time btree defrag, and an ioctl to force btree defrag
This adds two types of btree defrag, a run time form that tries to
defrag recently allocated blocks in the btree when they are still in ram,
and an ioctl that forces defrag of all btree blocks.
File data blocks are not defragged yet, but this can make a huge difference
in sequential btree reads.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index 7a08491..c7e47e7 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -65,16 +65,71 @@
memset(p, 0, sizeof(*p));
}
-static int btrfs_cow_block(struct btrfs_trans_handle *trans, struct btrfs_root
+static int __btrfs_cow_block(struct btrfs_trans_handle *trans, struct btrfs_root
+ *root, struct buffer_head *buf, struct buffer_head
+ *parent, int parent_slot, struct buffer_head
+ **cow_ret, u64 search_start, u64 empty_size)
+{
+ struct buffer_head *cow;
+ struct btrfs_node *cow_node;
+ int ret = 0;
+ int different_trans = 0;
+
+ WARN_ON(root->ref_cows && trans->transid != root->last_trans);
+ WARN_ON(!buffer_uptodate(buf));
+ cow = btrfs_alloc_free_block(trans, root, search_start, empty_size);
+ if (IS_ERR(cow))
+ return PTR_ERR(cow);
+
+ cow_node = btrfs_buffer_node(cow);
+ if (buf->b_size != root->blocksize || cow->b_size != root->blocksize)
+ WARN_ON(1);
+
+ memcpy(cow_node, btrfs_buffer_node(buf), root->blocksize);
+ btrfs_set_header_blocknr(&cow_node->header, bh_blocknr(cow));
+ btrfs_set_header_generation(&cow_node->header, trans->transid);
+ btrfs_set_header_owner(&cow_node->header, root->root_key.objectid);
+
+ WARN_ON(btrfs_header_generation(btrfs_buffer_header(buf)) >
+ trans->transid);
+ if (btrfs_header_generation(btrfs_buffer_header(buf)) !=
+ trans->transid) {
+ different_trans = 1;
+ ret = btrfs_inc_ref(trans, root, buf);
+ if (ret)
+ return ret;
+ } else {
+ WARN_ON(!root->ref_cows);
+ clean_tree_block(trans, root, buf);
+ }
+
+ if (buf == root->node) {
+ root->node = cow;
+ get_bh(cow);
+ if (buf != root->commit_root) {
+ btrfs_free_extent(trans, root, bh_blocknr(buf), 1, 1);
+ }
+ btrfs_block_release(root, buf);
+ } else {
+ btrfs_set_node_blockptr(btrfs_buffer_node(parent), parent_slot,
+ bh_blocknr(cow));
+ btrfs_mark_buffer_dirty(parent);
+ WARN_ON(btrfs_header_generation(btrfs_buffer_header(parent)) !=
+ trans->transid);
+ btrfs_free_extent(trans, root, bh_blocknr(buf), 1, 1);
+ }
+ btrfs_block_release(root, buf);
+ btrfs_mark_buffer_dirty(cow);
+ *cow_ret = cow;
+ return 0;
+}
+
+int btrfs_cow_block(struct btrfs_trans_handle *trans, struct btrfs_root
*root, struct buffer_head *buf, struct buffer_head
*parent, int parent_slot, struct buffer_head
**cow_ret)
{
- struct buffer_head *cow;
- struct btrfs_node *cow_node;
- int ret;
-
- WARN_ON(!buffer_uptodate(buf));
+ u64 search_start;
if (trans->transaction != root->fs_info->running_transaction) {
printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
root->fs_info->running_transaction->transid);
@@ -90,38 +145,94 @@
*cow_ret = buf;
return 0;
}
- cow = btrfs_alloc_free_block(trans, root, buf->b_blocknr);
- if (IS_ERR(cow))
- return PTR_ERR(cow);
- cow_node = btrfs_buffer_node(cow);
- if (buf->b_size != root->blocksize || cow->b_size != root->blocksize)
- WARN_ON(1);
- memcpy(cow_node, btrfs_buffer_node(buf), root->blocksize);
- btrfs_set_header_blocknr(&cow_node->header, bh_blocknr(cow));
- btrfs_set_header_generation(&cow_node->header, trans->transid);
- btrfs_set_header_owner(&cow_node->header, root->root_key.objectid);
- ret = btrfs_inc_ref(trans, root, buf);
- if (ret)
- return ret;
- if (buf == root->node) {
- root->node = cow;
- get_bh(cow);
- if (buf != root->commit_root) {
- btrfs_free_extent(trans, root, bh_blocknr(buf), 1, 1);
- }
- btrfs_block_release(root, buf);
- } else {
- btrfs_set_node_blockptr(btrfs_buffer_node(parent), parent_slot,
- bh_blocknr(cow));
- btrfs_mark_buffer_dirty(parent);
- btrfs_free_extent(trans, root, bh_blocknr(buf), 1, 1);
- }
- btrfs_block_release(root, buf);
- btrfs_mark_buffer_dirty(cow);
- *cow_ret = cow;
+
+ search_start = bh_blocknr(buf) & ~((u64)65535);
+ return __btrfs_cow_block(trans, root, buf, parent,
+ parent_slot, cow_ret, search_start, 0);
+}
+
+static int close_blocks(u64 blocknr, u64 other)
+{
+ if (blocknr < other && other - blocknr < 8)
+ return 1;
+ if (blocknr > other && blocknr - other < 8)
+ return 1;
return 0;
}
+int btrfs_realloc_node(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root, struct buffer_head *parent,
+ int cache_only)
+{
+ struct btrfs_node *parent_node;
+ struct buffer_head *cur_bh;
+ struct buffer_head *tmp_bh;
+ u64 blocknr;
+ u64 search_start = 0;
+ u64 other;
+ u32 parent_nritems;
+ int start_slot;
+ int end_slot;
+ int i;
+ int err = 0;
+
+ if (trans->transaction != root->fs_info->running_transaction) {
+ printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
+ root->fs_info->running_transaction->transid);
+ WARN_ON(1);
+ }
+ if (trans->transid != root->fs_info->generation) {
+ printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
+ root->fs_info->generation);
+ WARN_ON(1);
+ }
+ parent_node = btrfs_buffer_node(parent);
+ parent_nritems = btrfs_header_nritems(&parent_node->header);
+
+ start_slot = 0;
+ end_slot = parent_nritems;
+
+ if (parent_nritems == 1)
+ return 0;
+
+ for (i = start_slot; i < end_slot; i++) {
+ int close = 1;
+ blocknr = btrfs_node_blockptr(parent_node, i);
+ if (i > 0) {
+ other = btrfs_node_blockptr(parent_node, i - 1);
+ close = close_blocks(blocknr, other);
+ }
+ if (close && i < end_slot - 1) {
+ other = btrfs_node_blockptr(parent_node, i + 1);
+ close = close_blocks(blocknr, other);
+ }
+ if (close)
+ continue;
+
+ cur_bh = btrfs_find_tree_block(root, blocknr);
+ if (!cur_bh || !buffer_uptodate(cur_bh) ||
+ buffer_locked(cur_bh)) {
+ if (cache_only) {
+ brelse(cur_bh);
+ continue;
+ }
+ brelse(cur_bh);
+ cur_bh = read_tree_block(root, blocknr);
+ }
+ if (search_start == 0) {
+ search_start = bh_blocknr(cur_bh) & ~((u64)65535);
+ }
+ err = __btrfs_cow_block(trans, root, cur_bh, parent, i,
+ &tmp_bh, search_start,
+ min(8, end_slot - i));
+ if (err)
+ break;
+ search_start = bh_blocknr(tmp_bh);
+ brelse(tmp_bh);
+ }
+ return err;
+}
+
/*
* The leaf data grows from end-to-front in the node.
* this returns the address of the start of the last item,
@@ -221,6 +332,7 @@
parent_slot = path->slots[level + 1];
parent_key = &parent->ptrs[parent_slot].key;
+
BUG_ON(memcmp(parent_key, &leaf->items[0].key,
sizeof(struct btrfs_disk_key)));
BUG_ON(btrfs_node_blockptr(parent, parent_slot) !=
@@ -643,7 +755,7 @@
* readahead one full node of leaves
*/
static void reada_for_search(struct btrfs_root *root, struct btrfs_path *path,
- int slot)
+ int level, int slot)
{
struct btrfs_node *node;
int i;
@@ -659,10 +771,13 @@
unsigned long gang[8];
struct buffer_head *bh;
- if (!path->nodes[1])
+ if (level == 0)
return;
- node = btrfs_buffer_node(path->nodes[1]);
+ if (!path->nodes[level])
+ return;
+
+ node = btrfs_buffer_node(path->nodes[level]);
search = btrfs_node_blockptr(node, slot);
bh = btrfs_find_tree_block(root, search);
if (bh) {
@@ -690,7 +805,7 @@
for (i = 0; i < ret; i++) {
blocknr = gang[i];
clear_radix_bit(&found, blocknr);
- if (nread > 64)
+ if (nread > 32)
continue;
if (direction > 0 && cluster_start <= blocknr &&
cluster_start + 8 > blocknr) {
@@ -726,7 +841,6 @@
struct buffer_head *b;
struct buffer_head *cow_buf;
struct btrfs_node *c;
- struct btrfs_root_item *root_item = &root->root_item;
u64 blocknr;
int slot;
int ret;
@@ -734,11 +848,8 @@
int should_reada = p->reada;
u8 lowest_level = 0;
- if (btrfs_root_refs(root_item) == 0 && root->ref_cows) {
- lowest_level = root_item->drop_level;
- WARN_ON(ins_len || cow);
- }
-
+ lowest_level = p->lowest_level;
+ WARN_ON(lowest_level && ins_len);
WARN_ON(p->nodes[0] != NULL);
WARN_ON(!mutex_is_locked(&root->fs_info->fs_mutex));
again:
@@ -798,8 +909,8 @@
if (level == lowest_level)
break;
blocknr = btrfs_node_blockptr(c, slot);
- if (level == 1 && should_reada)
- reada_for_search(root, p, slot);
+ if (should_reada)
+ reada_for_search(root, p, level, slot);
b = read_tree_block(root, btrfs_node_blockptr(c, slot));
} else {
@@ -960,7 +1071,7 @@
BUG_ON(path->nodes[level]);
BUG_ON(path->nodes[level-1] != root->node);
- t = btrfs_alloc_free_block(trans, root, root->node->b_blocknr);
+ t = btrfs_alloc_free_block(trans, root, root->node->b_blocknr, 0);
if (IS_ERR(t))
return PTR_ERR(t);
c = btrfs_buffer_node(t);
@@ -1070,7 +1181,7 @@
}
c_nritems = btrfs_header_nritems(&c->header);
- split_buffer = btrfs_alloc_free_block(trans, root, t->b_blocknr);
+ split_buffer = btrfs_alloc_free_block(trans, root, t->b_blocknr, 0);
if (IS_ERR(split_buffer))
return PTR_ERR(split_buffer);
@@ -1461,7 +1572,7 @@
nritems = btrfs_header_nritems(&l->header);
mid = (nritems + 1)/ 2;
- right_buffer = btrfs_alloc_free_block(trans, root, l_buf->b_blocknr);
+ right_buffer = btrfs_alloc_free_block(trans, root, l_buf->b_blocknr, 0);
if (IS_ERR(right_buffer))
return PTR_ERR(right_buffer);
@@ -1560,7 +1671,7 @@
if (!double_split)
return ret;
- right_buffer = btrfs_alloc_free_block(trans, root, l_buf->b_blocknr);
+ right_buffer = btrfs_alloc_free_block(trans, root, l_buf->b_blocknr, 0);
if (IS_ERR(right_buffer))
return PTR_ERR(right_buffer);
@@ -1988,8 +2099,8 @@
blocknr = btrfs_node_blockptr(c_node, slot);
if (next)
btrfs_block_release(root, next);
- if (level == 1 && path->reada)
- reada_for_search(root, path, slot);
+ if (path->reada)
+ reada_for_search(root, path, level, slot);
next = read_tree_block(root, blocknr);
break;
}
@@ -2002,8 +2113,8 @@
path->slots[level] = 0;
if (!level)
break;
- if (level == 1 && path->reada)
- reada_for_search(root, path, slot);
+ if (path->reada)
+ reada_for_search(root, path, level, slot);
next = read_tree_block(root,
btrfs_node_blockptr(btrfs_buffer_node(next), 0));
}