Btrfs: reference counts on data extents
Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 82f6e9e..4d4fc48 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -13,7 +13,7 @@
btrfs_root *extent_root);
static int inc_block_ref(struct btrfs_trans_handle *trans, struct btrfs_root
- *root, u64 blocknr)
+ *root, u64 blocknr, u64 num_blocks)
{
struct btrfs_path path;
int ret;
@@ -29,7 +29,7 @@
key.objectid = blocknr;
key.flags = 0;
btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
- key.offset = 1;
+ key.offset = num_blocks;
ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key, &path,
0, 1);
if (ret != 0)
@@ -48,7 +48,7 @@
}
static int lookup_block_ref(struct btrfs_trans_handle *trans, struct btrfs_root
- *root, u64 blocknr, u32 *refs)
+ *root, u64 blocknr, u64 num_blocks, u32 *refs)
{
struct btrfs_path path;
int ret;
@@ -57,7 +57,7 @@
struct btrfs_extent_item *item;
btrfs_init_path(&path);
key.objectid = blocknr;
- key.offset = 1;
+ key.offset = num_blocks;
key.flags = 0;
btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key, &path,
@@ -76,17 +76,34 @@
{
u64 blocknr;
struct btrfs_node *buf_node;
+ struct btrfs_leaf *buf_leaf;
+ struct btrfs_disk_key *key;
+ struct btrfs_file_extent_item *fi;
int i;
+ int leaf;
+ int ret;
if (!root->ref_cows)
return 0;
buf_node = btrfs_buffer_node(buf);
- if (btrfs_is_leaf(buf_node))
- return 0;
-
+ leaf = btrfs_is_leaf(buf_node);
+ buf_leaf = btrfs_buffer_leaf(buf);
for (i = 0; i < btrfs_header_nritems(&buf_node->header); i++) {
- blocknr = btrfs_node_blockptr(buf_node, i);
- inc_block_ref(trans, root, blocknr);
+ if (leaf) {
+ key = &buf_leaf->items[i].key;
+ if (btrfs_disk_key_type(key) != BTRFS_EXTENT_DATA_KEY)
+ continue;
+ fi = btrfs_item_ptr(buf_leaf, i,
+ struct btrfs_file_extent_item);
+ ret = inc_block_ref(trans, root,
+ btrfs_file_extent_disk_blocknr(fi),
+ btrfs_file_extent_disk_num_blocks(fi));
+ BUG_ON(ret);
+ } else {
+ blocknr = btrfs_node_blockptr(buf_node, i);
+ ret = inc_block_ref(trans, root, blocknr, 1);
+ BUG_ON(ret);
+ }
}
return 0;
}
@@ -469,6 +486,37 @@
return buf;
}
+static int drop_leaf_ref(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root, struct buffer_head *cur)
+{
+ struct btrfs_disk_key *key;
+ struct btrfs_leaf *leaf;
+ struct btrfs_file_extent_item *fi;
+ int i;
+ int nritems;
+ int ret;
+
+ BUG_ON(!btrfs_is_leaf(btrfs_buffer_node(cur)));
+ leaf = btrfs_buffer_leaf(cur);
+ nritems = btrfs_header_nritems(&leaf->header);
+ for (i = 0; i < nritems; i++) {
+ key = &leaf->items[i].key;
+ if (btrfs_disk_key_type(key) != BTRFS_EXTENT_DATA_KEY)
+ continue;
+ fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
+ /*
+ * FIXME make sure to insert a trans record that
+ * repeats the snapshot del on crash
+ */
+ ret = btrfs_free_extent(trans, root,
+ btrfs_file_extent_disk_blocknr(fi),
+ btrfs_file_extent_disk_num_blocks(fi),
+ 0);
+ BUG_ON(ret);
+ }
+ return 0;
+}
+
/*
* helper function for drop_snapshot, this walks down the tree dropping ref
* counts as it goes.
@@ -483,28 +531,33 @@
u32 refs;
ret = lookup_block_ref(trans, root, path->nodes[*level]->b_blocknr,
- &refs);
+ 1, &refs);
BUG_ON(ret);
if (refs > 1)
goto out;
/*
* walk down to the last node level and free all the leaves
*/
- while(*level > 0) {
+ while(*level >= 0) {
cur = path->nodes[*level];
if (path->slots[*level] >=
btrfs_header_nritems(btrfs_buffer_header(cur)))
break;
+ if (*level == 0) {
+ ret = drop_leaf_ref(trans, root, cur);
+ BUG_ON(ret);
+ break;
+ }
blocknr = btrfs_node_blockptr(btrfs_buffer_node(cur),
path->slots[*level]);
- ret = lookup_block_ref(trans, root, blocknr, &refs);
- if (refs != 1 || *level == 1) {
+ ret = lookup_block_ref(trans, root, blocknr, 1, &refs);
+ BUG_ON(ret);
+ if (refs != 1) {
path->slots[*level]++;
ret = btrfs_free_extent(trans, root, blocknr, 1, 1);
BUG_ON(ret);
continue;
}
- BUG_ON(ret);
next = read_tree_block(root, blocknr);
if (path->nodes[*level-1])
btrfs_block_release(root, path->nodes[*level-1]);
@@ -513,8 +566,8 @@
path->slots[*level] = 0;
}
out:
- ret = btrfs_free_extent(trans, root, path->nodes[*level]->b_blocknr,
- 1, 1);
+ ret = btrfs_free_extent(trans, root,
+ path->nodes[*level]->b_blocknr, 1, 1);
btrfs_block_release(root, path->nodes[*level]);
path->nodes[*level] = NULL;
*level += 1;
@@ -544,10 +597,10 @@
ret = btrfs_free_extent(trans, root,
path->nodes[*level]->b_blocknr,
1, 1);
+ BUG_ON(ret);
btrfs_block_release(root, path->nodes[*level]);
path->nodes[*level] = NULL;
*level = i + 1;
- BUG_ON(ret);
}
}
return 1;
