forked from Mirrors/btrfs-progs
524 lines
13 KiB
C
524 lines
13 KiB
C
#include <stdio.h>
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#include <stdlib.h>
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#include "kerncompat.h"
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#include "radix-tree.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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static int find_free_extent(struct btrfs_root *orig_root, u64 num_blocks,
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u64 search_start, u64 search_end,
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struct btrfs_key *ins);
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static int finish_current_insert(struct btrfs_root *extent_root);
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static int run_pending(struct btrfs_root *extent_root);
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/*
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* pending extents are blocks that we're trying to allocate in the extent
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* map while trying to grow the map because of other allocations. To avoid
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* recursing, they are tagged in the radix tree and cleaned up after
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* other allocations are done. The pending tag is also used in the same
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* manner for deletes.
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*/
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#define CTREE_EXTENT_PENDING_DEL 0
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static int inc_block_ref(struct btrfs_root *root, u64 blocknr)
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{
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struct btrfs_path path;
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int ret;
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struct btrfs_key key;
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struct btrfs_leaf *l;
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struct btrfs_extent_item *item;
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struct btrfs_key ins;
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u32 refs;
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find_free_extent(root->extent_root, 0, 0, (u64)-1, &ins);
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btrfs_init_path(&path);
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key.objectid = blocknr;
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key.flags = 0;
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key.offset = 1;
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ret = btrfs_search_slot(root->extent_root, &key, &path, 0, 1);
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if (ret != 0)
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BUG();
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BUG_ON(ret != 0);
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l = &path.nodes[0]->leaf;
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item = (struct btrfs_extent_item *)(l->data +
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btrfs_item_offset(l->items +
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path.slots[0]));
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refs = btrfs_extent_refs(item);
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btrfs_set_extent_refs(item, refs + 1);
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BUG_ON(list_empty(&path.nodes[0]->dirty));
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btrfs_release_path(root->extent_root, &path);
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finish_current_insert(root->extent_root);
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run_pending(root->extent_root);
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return 0;
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}
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static int lookup_block_ref(struct btrfs_root *root, u64 blocknr, u32 *refs)
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{
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struct btrfs_path path;
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int ret;
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struct btrfs_key key;
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struct btrfs_leaf *l;
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struct btrfs_extent_item *item;
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btrfs_init_path(&path);
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key.objectid = blocknr;
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key.flags = 0;
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key.offset = 1;
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ret = btrfs_search_slot(root->extent_root, &key, &path, 0, 0);
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if (ret != 0)
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BUG();
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l = &path.nodes[0]->leaf;
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item = (struct btrfs_extent_item *)(l->data +
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btrfs_item_offset(l->items +
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path.slots[0]));
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*refs = btrfs_extent_refs(item);
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btrfs_release_path(root->extent_root, &path);
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return 0;
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}
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int btrfs_inc_ref(struct btrfs_root *root, struct btrfs_buffer *buf)
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{
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u64 blocknr;
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int i;
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if (root == root->extent_root)
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return 0;
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if (btrfs_is_leaf(&buf->node))
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return 0;
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for (i = 0; i < btrfs_header_nritems(&buf->node.header); i++) {
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blocknr = btrfs_node_blockptr(&buf->node, i);
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inc_block_ref(root, blocknr);
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}
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return 0;
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}
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int btrfs_finish_extent_commit(struct btrfs_root *root)
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{
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struct btrfs_root *extent_root = root->extent_root;
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unsigned long gang[8];
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int ret;
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int i;
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while(1) {
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ret = radix_tree_gang_lookup(&extent_root->pinned_radix,
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(void **)gang, 0,
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ARRAY_SIZE(gang));
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if (!ret)
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break;
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for (i = 0; i < ret; i++) {
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radix_tree_delete(&extent_root->pinned_radix, gang[i]);
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}
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}
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extent_root->last_insert.objectid = 0;
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extent_root->last_insert.offset = 0;
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return 0;
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}
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static int finish_current_insert(struct btrfs_root *extent_root)
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{
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struct btrfs_key ins;
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struct btrfs_extent_item extent_item;
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int i;
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int ret;
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btrfs_set_extent_refs(&extent_item, 1);
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btrfs_set_extent_owner(&extent_item,
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btrfs_header_parentid(&extent_root->node->node.header));
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ins.offset = 1;
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ins.flags = 0;
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for (i = 0; i < extent_root->current_insert.flags; i++) {
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ins.objectid = extent_root->current_insert.objectid + i;
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ret = btrfs_insert_item(extent_root, &ins, &extent_item,
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sizeof(extent_item));
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BUG_ON(ret);
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}
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extent_root->current_insert.offset = 0;
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return 0;
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}
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/*
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* remove an extent from the root, returns 0 on success
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*/
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static int __free_extent(struct btrfs_root *root, u64 blocknr, u64 num_blocks)
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{
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struct btrfs_path path;
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struct btrfs_key key;
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struct btrfs_root *extent_root = root->extent_root;
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int ret;
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struct btrfs_item *item;
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struct btrfs_extent_item *ei;
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struct btrfs_key ins;
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u32 refs;
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key.objectid = blocknr;
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key.flags = 0;
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key.offset = num_blocks;
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find_free_extent(root, 0, 0, (u64)-1, &ins);
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btrfs_init_path(&path);
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ret = btrfs_search_slot(extent_root, &key, &path, -1, 1);
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if (ret) {
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printf("failed to find %Lu\n", key.objectid);
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btrfs_print_tree(extent_root, extent_root->node);
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printf("failed to find %Lu\n", key.objectid);
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BUG();
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}
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item = path.nodes[0]->leaf.items + path.slots[0];
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ei = (struct btrfs_extent_item *)(path.nodes[0]->leaf.data +
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btrfs_item_offset(item));
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BUG_ON(ei->refs == 0);
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refs = btrfs_extent_refs(ei) - 1;
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btrfs_set_extent_refs(ei, refs);
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if (refs == 0) {
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if (root == extent_root) {
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int err;
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radix_tree_preload(GFP_KERNEL);
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err = radix_tree_insert(&extent_root->pinned_radix,
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blocknr, (void *)blocknr);
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BUG_ON(err);
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radix_tree_preload_end();
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}
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ret = btrfs_del_item(extent_root, &path);
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if (root != extent_root &&
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extent_root->last_insert.objectid < blocknr)
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extent_root->last_insert.objectid = blocknr;
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if (ret)
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BUG();
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}
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btrfs_release_path(extent_root, &path);
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finish_current_insert(extent_root);
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return ret;
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}
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/*
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* find all the blocks marked as pending in the radix tree and remove
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* them from the extent map
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*/
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static int del_pending_extents(struct btrfs_root *extent_root)
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{
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int ret;
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struct btrfs_buffer *gang[4];
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int i;
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while(1) {
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ret = radix_tree_gang_lookup_tag(&extent_root->cache_radix,
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(void **)gang, 0,
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ARRAY_SIZE(gang),
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CTREE_EXTENT_PENDING_DEL);
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if (!ret)
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break;
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for (i = 0; i < ret; i++) {
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ret = __free_extent(extent_root, gang[i]->blocknr, 1);
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radix_tree_tag_clear(&extent_root->cache_radix,
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gang[i]->blocknr,
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CTREE_EXTENT_PENDING_DEL);
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btrfs_block_release(extent_root, gang[i]);
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}
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}
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return 0;
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}
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static int run_pending(struct btrfs_root *extent_root)
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{
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while(radix_tree_tagged(&extent_root->cache_radix,
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CTREE_EXTENT_PENDING_DEL))
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del_pending_extents(extent_root);
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return 0;
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}
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/*
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* remove an extent from the root, returns 0 on success
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*/
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int btrfs_free_extent(struct btrfs_root *root, u64 blocknr, u64 num_blocks)
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{
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struct btrfs_key key;
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struct btrfs_root *extent_root = root->extent_root;
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struct btrfs_buffer *t;
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int pending_ret;
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int ret;
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if (root == extent_root) {
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t = find_tree_block(root, blocknr);
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radix_tree_tag_set(&root->cache_radix, blocknr,
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CTREE_EXTENT_PENDING_DEL);
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return 0;
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}
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key.objectid = blocknr;
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key.flags = 0;
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key.offset = num_blocks;
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ret = __free_extent(root, blocknr, num_blocks);
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pending_ret = run_pending(root->extent_root);
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return ret ? ret : pending_ret;
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}
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/*
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* walks the btree of allocated extents and find a hole of a given size.
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* The key ins is changed to record the hole:
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* ins->objectid == block start
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* ins->flags = 0
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* ins->offset == number of blocks
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* Any available blocks before search_start are skipped.
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*/
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static int find_free_extent(struct btrfs_root *orig_root, u64 num_blocks,
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u64 search_start, u64 search_end,
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struct btrfs_key *ins)
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{
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struct btrfs_path path;
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struct btrfs_key key;
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int ret;
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u64 hole_size = 0;
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int slot = 0;
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u64 last_block;
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u64 test_block;
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int start_found;
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struct btrfs_leaf *l;
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struct btrfs_root * root = orig_root->extent_root;
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int total_needed = num_blocks;
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total_needed += (btrfs_header_level(&root->node->node.header) + 1) * 3;
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if (root->last_insert.objectid > search_start)
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search_start = root->last_insert.objectid;
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check_failed:
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btrfs_init_path(&path);
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ins->objectid = search_start;
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ins->offset = 0;
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ins->flags = 0;
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start_found = 0;
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ret = btrfs_search_slot(root, ins, &path, 0, 0);
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if (ret < 0)
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goto error;
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if (path.slots[0] > 0)
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path.slots[0]--;
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while (1) {
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l = &path.nodes[0]->leaf;
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slot = path.slots[0];
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if (slot >= btrfs_header_nritems(&l->header)) {
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ret = btrfs_next_leaf(root, &path);
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if (ret == 0)
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continue;
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if (ret < 0)
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goto error;
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if (!start_found) {
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ins->objectid = search_start;
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ins->offset = (u64)-1;
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start_found = 1;
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goto check_pending;
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}
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ins->objectid = last_block > search_start ?
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last_block : search_start;
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ins->offset = (u64)-1;
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goto check_pending;
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}
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btrfs_disk_key_to_cpu(&key, &l->items[slot].key);
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if (key.objectid >= search_start) {
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if (start_found) {
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if (last_block < search_start)
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last_block = search_start;
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hole_size = key.objectid - last_block;
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if (hole_size > total_needed) {
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ins->objectid = last_block;
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ins->offset = hole_size;
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goto check_pending;
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}
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}
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}
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start_found = 1;
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last_block = key.objectid + key.offset;
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path.slots[0]++;
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}
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// FIXME -ENOSPC
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check_pending:
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/* we have to make sure we didn't find an extent that has already
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* been allocated by the map tree or the original allocation
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*/
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btrfs_release_path(root, &path);
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BUG_ON(ins->objectid < search_start);
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for (test_block = ins->objectid;
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test_block < ins->objectid + total_needed; test_block++) {
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if (radix_tree_lookup(&root->pinned_radix, test_block)) {
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search_start = test_block + 1;
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goto check_failed;
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}
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}
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BUG_ON(root->current_insert.offset);
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root->current_insert.offset = total_needed - num_blocks;
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root->current_insert.objectid = ins->objectid + num_blocks;
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root->current_insert.flags = 0;
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root->last_insert.objectid = ins->objectid;
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ins->offset = num_blocks;
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return 0;
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error:
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btrfs_release_path(root, &path);
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return ret;
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}
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/*
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* finds a free extent and does all the dirty work required for allocation
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* returns the key for the extent through ins, and a tree buffer for
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* the first block of the extent through buf.
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*
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* returns 0 if everything worked, non-zero otherwise.
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*/
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int alloc_extent(struct btrfs_root *root, u64 num_blocks, u64 search_start,
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u64 search_end, u64 owner, struct btrfs_key *ins)
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{
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int ret;
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int pending_ret;
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struct btrfs_root *extent_root = root->extent_root;
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struct btrfs_extent_item extent_item;
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btrfs_set_extent_refs(&extent_item, 1);
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btrfs_set_extent_owner(&extent_item, owner);
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if (root == extent_root) {
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BUG_ON(extent_root->current_insert.offset == 0);
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BUG_ON(num_blocks != 1);
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BUG_ON(extent_root->current_insert.flags ==
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extent_root->current_insert.offset);
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ins->offset = 1;
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ins->objectid = extent_root->current_insert.objectid +
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extent_root->current_insert.flags++;
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return 0;
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}
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ret = find_free_extent(root, num_blocks, search_start,
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search_end, ins);
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if (ret)
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return ret;
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ret = btrfs_insert_item(extent_root, ins, &extent_item,
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sizeof(extent_item));
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finish_current_insert(extent_root);
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pending_ret = run_pending(extent_root);
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if (ret)
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return ret;
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if (pending_ret)
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return pending_ret;
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return 0;
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}
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/*
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* helper function to allocate a block for a given tree
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* returns the tree buffer or NULL.
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*/
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struct btrfs_buffer *btrfs_alloc_free_block(struct btrfs_root *root)
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{
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struct btrfs_key ins;
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int ret;
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struct btrfs_buffer *buf;
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ret = alloc_extent(root, 1, 0, (unsigned long)-1,
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btrfs_header_parentid(&root->node->node.header),
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&ins);
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if (ret) {
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BUG();
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return NULL;
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}
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buf = find_tree_block(root, ins.objectid);
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dirty_tree_block(root, buf);
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return buf;
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}
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int walk_down_tree(struct btrfs_root *root, struct btrfs_path *path, int *level)
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{
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struct btrfs_buffer *next;
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struct btrfs_buffer *cur;
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u64 blocknr;
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int ret;
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u32 refs;
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ret = lookup_block_ref(root, path->nodes[*level]->blocknr, &refs);
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BUG_ON(ret);
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if (refs > 1)
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goto out;
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while(*level > 0) {
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cur = path->nodes[*level];
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if (path->slots[*level] >=
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btrfs_header_nritems(&cur->node.header))
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break;
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blocknr = btrfs_node_blockptr(&cur->node, path->slots[*level]);
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ret = lookup_block_ref(root, blocknr, &refs);
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if (refs != 1 || *level == 1) {
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path->slots[*level]++;
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ret = btrfs_free_extent(root, blocknr, 1);
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BUG_ON(ret);
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continue;
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}
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BUG_ON(ret);
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next = read_tree_block(root, blocknr);
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if (path->nodes[*level-1])
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btrfs_block_release(root, path->nodes[*level-1]);
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path->nodes[*level-1] = next;
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*level = btrfs_header_level(&next->node.header);
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path->slots[*level] = 0;
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}
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out:
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ret = btrfs_free_extent(root, path->nodes[*level]->blocknr, 1);
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btrfs_block_release(root, path->nodes[*level]);
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path->nodes[*level] = NULL;
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*level += 1;
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BUG_ON(ret);
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return 0;
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}
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int walk_up_tree(struct btrfs_root *root, struct btrfs_path *path, int *level)
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{
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int i;
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int slot;
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int ret;
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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 <
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btrfs_header_nritems(&path->nodes[i]->node.header)- 1) {
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path->slots[i]++;
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*level = i;
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return 0;
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} else {
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ret = btrfs_free_extent(root,
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path->nodes[*level]->blocknr, 1);
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btrfs_block_release(root, path->nodes[*level]);
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path->nodes[*level] = NULL;
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*level = i + 1;
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BUG_ON(ret);
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}
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}
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return 1;
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}
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int btrfs_drop_snapshot(struct btrfs_root *root, struct btrfs_buffer *snap)
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{
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|
int ret;
|
|
int level;
|
|
struct btrfs_path path;
|
|
int i;
|
|
int orig_level;
|
|
|
|
btrfs_init_path(&path);
|
|
|
|
level = btrfs_header_level(&snap->node.header);
|
|
orig_level = level;
|
|
path.nodes[level] = snap;
|
|
path.slots[level] = 0;
|
|
while(1) {
|
|
ret = walk_down_tree(root, &path, &level);
|
|
if (ret > 0)
|
|
break;
|
|
ret = walk_up_tree(root, &path, &level);
|
|
if (ret > 0)
|
|
break;
|
|
}
|
|
for (i = 0; i <= orig_level; i++) {
|
|
if (path.nodes[i]) {
|
|
btrfs_block_release(root, path.nodes[i]);
|
|
}
|
|
}
|
|
|
|
return 0;
|
|
}
|