Btrfs: Add fsx-style randomized tree tester
Add debug-tree command to print the tree
Add extent-tree.c to the repo
Comment ctree.h
Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
new file mode 100644
index 0000000..2b663ef
--- /dev/null
+++ b/fs/btrfs/extent-tree.c
@@ -0,0 +1,296 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include "kerncompat.h"
+#include "radix-tree.h"
+#include "ctree.h"
+#include "disk-io.h"
+#include "print-tree.h"
+
+/*
+ * pending extents are blocks that we're trying to allocate in the extent
+ * map while trying to grow the map because of other allocations. To avoid
+ * recursing, they are tagged in the radix tree and cleaned up after
+ * other allocations are done. The pending tag is also used in the same
+ * manner for deletes.
+ */
+#define CTREE_EXTENT_PENDING 0
+
+/*
+ * find all the blocks marked as pending in the radix tree and remove
+ * them from the extent map
+ */
+static int del_pending_extents(struct ctree_root *extent_root)
+{
+ int ret;
+ struct key key;
+ struct tree_buffer *gang[4];
+ int i;
+ struct ctree_path path;
+
+ while(1) {
+ ret = radix_tree_gang_lookup_tag(&extent_root->cache_radix,
+ (void **)gang, 0,
+ ARRAY_SIZE(gang),
+ CTREE_EXTENT_PENDING);
+ if (!ret)
+ break;
+ for (i = 0; i < ret; i++) {
+ key.objectid = gang[i]->blocknr;
+ key.flags = 0;
+ key.offset = 1;
+ init_path(&path);
+ ret = search_slot(extent_root, &key, &path, 0);
+ if (ret) {
+ print_tree(extent_root, extent_root->node);
+ printf("unable to find %lu\n", key.objectid);
+ BUG();
+ // FIXME undo it and return sane
+ return ret;
+ }
+ ret = del_item(extent_root, &path);
+ if (ret) {
+ BUG();
+ return ret;
+ }
+ release_path(extent_root, &path);
+ radix_tree_tag_clear(&extent_root->cache_radix,
+ gang[i]->blocknr,
+ CTREE_EXTENT_PENDING);
+ tree_block_release(extent_root, gang[i]);
+ }
+ }
+ return 0;
+}
+
+/*
+ * remove an extent from the root, returns 0 on success
+ */
+int free_extent(struct ctree_root *root, u64 blocknr, u64 num_blocks)
+{
+ struct ctree_path path;
+ struct key key;
+ struct ctree_root *extent_root = root->extent_root;
+ struct tree_buffer *t;
+ int pending_ret;
+ int ret;
+ key.objectid = blocknr;
+ key.flags = 0;
+ key.offset = num_blocks;
+ if (root == extent_root) {
+ t = read_tree_block(root, key.objectid);
+ radix_tree_tag_set(&root->cache_radix, key.objectid,
+ CTREE_EXTENT_PENDING);
+ return 0;
+ }
+ init_path(&path);
+ ret = search_slot(extent_root, &key, &path, 0);
+ if (ret) {
+ print_tree(extent_root, extent_root->node);
+ printf("failed to find %lu\n", key.objectid);
+ BUG();
+ }
+ ret = del_item(extent_root, &path);
+ if (ret)
+ BUG();
+ release_path(extent_root, &path);
+ pending_ret = del_pending_extents(root->extent_root);
+ return ret ? ret : pending_ret;
+}
+
+/*
+ * walks the btree of allocated extents and find a hole of a given size.
+ * The key ins is changed to record the hole:
+ * ins->objectid == block start
+ * ins->flags = 0
+ * ins->offset == number of blocks
+ * Any available blocks before search_start are skipped.
+ */
+int find_free_extent(struct ctree_root *orig_root, u64 num_blocks,
+ u64 search_start, u64 search_end, struct key *ins)
+{
+ struct ctree_path path;
+ struct key *key;
+ int ret;
+ u64 hole_size = 0;
+ int slot = 0;
+ u64 last_block;
+ int start_found;
+ struct leaf *l;
+ struct ctree_root * root = orig_root->extent_root;
+
+check_failed:
+ init_path(&path);
+ ins->objectid = search_start;
+ ins->offset = 0;
+ ins->flags = 0;
+ start_found = 0;
+ ret = search_slot(root, ins, &path, 0);
+ while (1) {
+ l = &path.nodes[0]->leaf;
+ slot = path.slots[0];
+ if (slot >= l->header.nritems) {
+ ret = next_leaf(root, &path);
+ if (ret == 0)
+ continue;
+ if (!start_found) {
+ ins->objectid = search_start;
+ ins->offset = num_blocks;
+ start_found = 1;
+ goto check_pending;
+ }
+ ins->objectid = last_block > search_start ?
+ last_block : search_start;
+ ins->offset = num_blocks;
+ goto check_pending;
+ }
+ key = &l->items[slot].key;
+ if (key->objectid >= search_start) {
+ if (start_found) {
+ hole_size = key->objectid - last_block;
+ if (hole_size > num_blocks) {
+ ins->objectid = last_block;
+ ins->offset = num_blocks;
+ goto check_pending;
+ }
+ } else
+ start_found = 1;
+ last_block = key->objectid + key->offset;
+ }
+ path.slots[0]++;
+ }
+ // FIXME -ENOSPC
+check_pending:
+ /* we have to make sure we didn't find an extent that has already
+ * been allocated by the map tree or the original allocation
+ */
+ release_path(root, &path);
+ BUG_ON(ins->objectid < search_start);
+ if (orig_root->extent_root == orig_root) {
+ BUG_ON(num_blocks != 1);
+ if ((root->current_insert.objectid <= ins->objectid &&
+ root->current_insert.objectid +
+ root->current_insert.offset > ins->objectid) ||
+ (root->current_insert.objectid > ins->objectid &&
+ root->current_insert.objectid <= ins->objectid +
+ ins->offset) ||
+ radix_tree_tag_get(&root->cache_radix, ins->objectid,
+ CTREE_EXTENT_PENDING)) {
+ search_start = ins->objectid + 1;
+ goto check_failed;
+ }
+ }
+ if (ins->offset != 1)
+ BUG();
+ return 0;
+}
+
+/*
+ * insert all of the pending extents reserved during the original
+ * allocation. (CTREE_EXTENT_PENDING). Returns zero if it all worked out
+ */
+static int insert_pending_extents(struct ctree_root *extent_root)
+{
+ int ret;
+ struct key key;
+ struct extent_item item;
+ struct tree_buffer *gang[4];
+ int i;
+
+ // FIXME -ENOSPC
+ item.refs = 1;
+ item.owner = extent_root->node->node.header.parentid;
+ while(1) {
+ ret = radix_tree_gang_lookup_tag(&extent_root->cache_radix,
+ (void **)gang, 0,
+ ARRAY_SIZE(gang),
+ CTREE_EXTENT_PENDING);
+ if (!ret)
+ break;
+ for (i = 0; i < ret; i++) {
+ key.objectid = gang[i]->blocknr;
+ key.flags = 0;
+ key.offset = 1;
+ ret = insert_item(extent_root, &key, &item,
+ sizeof(item));
+ if (ret) {
+ BUG();
+ // FIXME undo it and return sane
+ return ret;
+ }
+ radix_tree_tag_clear(&extent_root->cache_radix,
+ gang[i]->blocknr,
+ CTREE_EXTENT_PENDING);
+ tree_block_release(extent_root, gang[i]);
+ }
+ }
+ return 0;
+}
+
+/*
+ * finds a free extent and does all the dirty work required for allocation
+ * returns the key for the extent through ins, and a tree buffer for
+ * the first block of the extent through buf.
+ *
+ * returns 0 if everything worked, non-zero otherwise.
+ */
+int alloc_extent(struct ctree_root *root, u64 num_blocks, u64 search_start,
+ u64 search_end, u64 owner, struct key *ins,
+ struct tree_buffer **buf)
+{
+ int ret;
+ int pending_ret;
+ struct extent_item extent_item;
+ extent_item.refs = 1;
+ extent_item.owner = owner;
+
+ ret = find_free_extent(root, num_blocks, search_start, search_end, ins);
+ if (ret)
+ return ret;
+ if (root != root->extent_root) {
+ memcpy(&root->extent_root->current_insert, ins, sizeof(*ins));
+ ret = insert_item(root->extent_root, ins, &extent_item,
+ sizeof(extent_item));
+ memset(&root->extent_root->current_insert, 0,
+ sizeof(struct key));
+ pending_ret = insert_pending_extents(root->extent_root);
+ if (ret)
+ return ret;
+ if (pending_ret)
+ return pending_ret;
+ *buf = find_tree_block(root, ins->objectid);
+ return 0;
+ }
+ /* we're allocating an extent for the extent tree, don't recurse */
+ BUG_ON(ins->offset != 1);
+ *buf = find_tree_block(root, ins->objectid);
+ BUG_ON(!*buf);
+ radix_tree_tag_set(&root->cache_radix, ins->objectid,
+ CTREE_EXTENT_PENDING);
+ (*buf)->count++;
+ return 0;
+
+}
+
+/*
+ * helper function to allocate a block for a given tree
+ * returns the tree buffer or NULL.
+ */
+struct tree_buffer *alloc_free_block(struct ctree_root *root)
+{
+ struct key ins;
+ int ret;
+ struct tree_buffer *buf = NULL;
+
+ ret = alloc_extent(root, 1, 0, (unsigned long)-1,
+ root->node->node.header.parentid,
+ &ins, &buf);
+
+ if (ret) {
+ BUG();
+ return NULL;
+ }
+ if (root != root->extent_root)
+ BUG_ON(radix_tree_tag_get(&root->extent_root->cache_radix,
+ buf->blocknr, CTREE_EXTENT_PENDING));
+ return buf;
+}