612 lines
16 KiB
C
612 lines
16 KiB
C
#include <linux/module.h>
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#include <linux/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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#include "transaction.h"
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static int find_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
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*orig_root, u64 num_blocks, u64 search_start, u64
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search_end, struct btrfs_key *ins);
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static int finish_current_insert(struct btrfs_trans_handle *trans, struct
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btrfs_root *extent_root);
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static int del_pending_extents(struct btrfs_trans_handle *trans, struct
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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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#define CTREE_EXTENT_PINNED 1
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static int inc_block_ref(struct btrfs_trans_handle *trans, struct btrfs_root
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*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(trans, root->fs_info->extent_root, 0, 0, (u64)-1,
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&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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btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
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key.offset = 1;
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ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key, &path,
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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 = btrfs_buffer_leaf(path.nodes[0]);
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item = btrfs_item_ptr(l, path.slots[0], struct btrfs_extent_item);
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refs = btrfs_extent_refs(item);
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btrfs_set_extent_refs(item, refs + 1);
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mark_buffer_dirty(path.nodes[0]);
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btrfs_release_path(root->fs_info->extent_root, &path);
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finish_current_insert(trans, root->fs_info->extent_root);
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del_pending_extents(trans, root->fs_info->extent_root);
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return 0;
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}
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static int lookup_block_ref(struct btrfs_trans_handle *trans, struct btrfs_root
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*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.offset = 1;
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key.flags = 0;
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btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
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ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key, &path,
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0, 0);
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if (ret != 0)
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BUG();
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l = btrfs_buffer_leaf(path.nodes[0]);
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item = btrfs_item_ptr(l, path.slots[0], struct btrfs_extent_item);
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*refs = btrfs_extent_refs(item);
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btrfs_release_path(root->fs_info->extent_root, &path);
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return 0;
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}
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int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
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struct buffer_head *buf)
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{
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u64 blocknr;
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struct btrfs_node *buf_node;
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int i;
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if (!root->ref_cows)
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return 0;
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buf_node = btrfs_buffer_node(buf);
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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(trans, 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_trans_handle *trans, struct
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btrfs_root *root)
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{
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struct buffer_head *gang[8];
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u64 first = 0;
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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_tag(&root->fs_info->pinned_radix,
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(void **)gang, 0,
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ARRAY_SIZE(gang),
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CTREE_EXTENT_PINNED);
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if (!ret)
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break;
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if (!first)
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first = gang[0]->b_blocknr;
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for (i = 0; i < ret; i++) {
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radix_tree_delete(&root->fs_info->pinned_radix,
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gang[i]->b_blocknr);
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brelse(gang[i]);
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}
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}
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if (root->fs_info->last_insert.objectid > first)
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root->fs_info->last_insert.objectid = first;
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root->fs_info->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_trans_handle *trans, struct
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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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u64 super_blocks_used;
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struct btrfs_fs_info *info = extent_root->fs_info;
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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(btrfs_buffer_header(extent_root->node)));
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ins.offset = 1;
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ins.flags = 0;
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btrfs_set_key_type(&ins, BTRFS_EXTENT_ITEM_KEY);
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for (i = 0; i < extent_root->fs_info->current_insert.flags; i++) {
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ins.objectid = extent_root->fs_info->current_insert.objectid +
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i;
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super_blocks_used = btrfs_super_blocks_used(info->disk_super);
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btrfs_set_super_blocks_used(info->disk_super,
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super_blocks_used + 1);
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ret = btrfs_insert_item(trans, 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->fs_info->current_insert.offset = 0;
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return 0;
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}
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static int pin_down_block(struct btrfs_root *root, u64 blocknr, int tag)
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{
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int err;
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struct buffer_head *bh = sb_getblk(root->fs_info->sb, blocknr);
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struct btrfs_header *header;
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BUG_ON(!bh);
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header = btrfs_buffer_header(bh);
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if (btrfs_header_generation(header) ==
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root->fs_info->running_transaction->transid) {
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return 0;
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}
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err = radix_tree_insert(&root->fs_info->pinned_radix,
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blocknr, bh);
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if (err && err != -EEXIST) {
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BUG();
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return err;
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}
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if (err == -EEXIST)
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brelse(bh);
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radix_tree_tag_set(&root->fs_info->pinned_radix, blocknr,
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tag);
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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_trans_handle *trans, struct btrfs_root
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*root, u64 blocknr, u64 num_blocks, int pin)
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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_fs_info *info = root->fs_info;
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struct btrfs_root *extent_root = info->extent_root;
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int ret;
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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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btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
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key.offset = num_blocks;
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find_free_extent(trans, root, 0, 0, (u64)-1, &ins);
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btrfs_init_path(&path);
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ret = btrfs_search_slot(trans, extent_root, &key, &path, -1, 1);
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if (ret) {
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printk("failed to find %Lu\n", key.objectid);
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btrfs_print_tree(extent_root, extent_root->node);
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printk("failed to find %Lu\n", key.objectid);
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BUG();
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}
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ei = btrfs_item_ptr(btrfs_buffer_leaf(path.nodes[0]), path.slots[0],
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struct btrfs_extent_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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u64 super_blocks_used;
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if (pin) {
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ret = pin_down_block(root, blocknr,
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CTREE_EXTENT_PINNED);
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BUG_ON(ret);
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}
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super_blocks_used = btrfs_super_blocks_used(info->disk_super);
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btrfs_set_super_blocks_used(info->disk_super,
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super_blocks_used - num_blocks);
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ret = btrfs_del_item(trans, extent_root, &path);
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if (extent_root->fs_info->last_insert.objectid > blocknr)
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extent_root->fs_info->last_insert.objectid = blocknr;
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if (ret)
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BUG();
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}
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mark_buffer_dirty(path.nodes[0]);
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btrfs_release_path(extent_root, &path);
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finish_current_insert(trans, 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_trans_handle *trans, struct
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btrfs_root *extent_root)
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{
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int ret;
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int wret;
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int err = 0;
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struct buffer_head *gang[4];
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int i;
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struct radix_tree_root *radix = &extent_root->fs_info->pinned_radix;
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while(1) {
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ret = radix_tree_gang_lookup_tag(
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&extent_root->fs_info->pinned_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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radix_tree_tag_set(radix, gang[i]->b_blocknr,
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CTREE_EXTENT_PINNED);
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radix_tree_tag_clear(radix, gang[i]->b_blocknr,
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CTREE_EXTENT_PENDING_DEL);
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wret = __free_extent(trans, extent_root,
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gang[i]->b_blocknr, 1, 0);
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if (wret)
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err = wret;
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}
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}
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return err;
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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_trans_handle *trans, struct btrfs_root
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*root, u64 blocknr, u64 num_blocks, int pin)
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{
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struct btrfs_root *extent_root = root->fs_info->extent_root;
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struct buffer_head *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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pin_down_block(root, blocknr, CTREE_EXTENT_PENDING_DEL);
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return 0;
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}
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ret = __free_extent(trans, root, blocknr, num_blocks, pin);
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pending_ret = del_pending_extents(trans, root->fs_info->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 = BTRFS_EXTENT_ITEM_KEY
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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_trans_handle *trans, struct btrfs_root
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*orig_root, u64 num_blocks, u64 search_start, u64
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search_end, 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 = 0;
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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->fs_info->extent_root;
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int total_needed = num_blocks;
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int level;
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level = btrfs_header_level(btrfs_buffer_header(root->node));
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total_needed += (level + 1) * 3;
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if (root->fs_info->last_insert.objectid > search_start)
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search_start = root->fs_info->last_insert.objectid;
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ins->flags = 0;
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btrfs_set_key_type(ins, BTRFS_EXTENT_ITEM_KEY);
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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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start_found = 0;
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ret = btrfs_search_slot(trans, 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 = btrfs_buffer_leaf(path.nodes[0]);
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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->fs_info->pinned_radix,
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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->fs_info->current_insert.offset);
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root->fs_info->current_insert.offset = total_needed - num_blocks;
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root->fs_info->current_insert.objectid = ins->objectid + num_blocks;
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root->fs_info->current_insert.flags = 0;
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root->fs_info->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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static int alloc_extent(struct btrfs_trans_handle *trans, struct btrfs_root
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*root, u64 num_blocks, u64 search_start, u64
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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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u64 super_blocks_used;
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struct btrfs_fs_info *info = root->fs_info;
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struct btrfs_root *extent_root = info->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->fs_info->current_insert.offset == 0);
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BUG_ON(num_blocks != 1);
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BUG_ON(extent_root->fs_info->current_insert.flags ==
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extent_root->fs_info->current_insert.offset);
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ins->offset = 1;
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ins->objectid = extent_root->fs_info->current_insert.objectid +
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extent_root->fs_info->current_insert.flags++;
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return 0;
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}
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ret = find_free_extent(trans, 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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super_blocks_used = btrfs_super_blocks_used(info->disk_super);
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btrfs_set_super_blocks_used(info->disk_super, super_blocks_used +
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num_blocks);
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ret = btrfs_insert_item(trans, extent_root, ins, &extent_item,
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sizeof(extent_item));
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finish_current_insert(trans, extent_root);
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pending_ret = del_pending_extents(trans, 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 buffer_head *btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
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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 buffer_head *buf;
|
|
|
|
ret = alloc_extent(trans, root, 1, 0, (unsigned long)-1,
|
|
btrfs_header_parentid(btrfs_buffer_header(root->node)), &ins);
|
|
if (ret) {
|
|
BUG();
|
|
return NULL;
|
|
}
|
|
buf = find_tree_block(root, ins.objectid);
|
|
set_buffer_uptodate(buf);
|
|
return buf;
|
|
}
|
|
|
|
/*
|
|
* helper function for drop_snapshot, this walks down the tree dropping ref
|
|
* counts as it goes.
|
|
*/
|
|
static int walk_down_tree(struct btrfs_trans_handle *trans, struct btrfs_root
|
|
*root, struct btrfs_path *path, int *level)
|
|
{
|
|
struct buffer_head *next;
|
|
struct buffer_head *cur;
|
|
u64 blocknr;
|
|
int ret;
|
|
u32 refs;
|
|
|
|
ret = lookup_block_ref(trans, root, path->nodes[*level]->b_blocknr,
|
|
&refs);
|
|
BUG_ON(ret);
|
|
if (refs > 1)
|
|
goto out;
|
|
/*
|
|
* walk down to the last node level and free all the leaves
|
|
*/
|
|
while(*level > 0) {
|
|
cur = path->nodes[*level];
|
|
if (path->slots[*level] >=
|
|
btrfs_header_nritems(btrfs_buffer_header(cur)))
|
|
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) {
|
|
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]);
|
|
path->nodes[*level-1] = next;
|
|
*level = btrfs_header_level(btrfs_buffer_header(next));
|
|
path->slots[*level] = 0;
|
|
}
|
|
out:
|
|
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;
|
|
BUG_ON(ret);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* helper for dropping snapshots. This walks back up the tree in the path
|
|
* to find the first node higher up where we haven't yet gone through
|
|
* all the slots
|
|
*/
|
|
static int walk_up_tree(struct btrfs_trans_handle *trans, struct btrfs_root
|
|
*root, struct btrfs_path *path, int *level)
|
|
{
|
|
int i;
|
|
int slot;
|
|
int ret;
|
|
for(i = *level; i < BTRFS_MAX_LEVEL - 1 && path->nodes[i]; i++) {
|
|
slot = path->slots[i];
|
|
if (slot < btrfs_header_nritems(
|
|
btrfs_buffer_header(path->nodes[i])) - 1) {
|
|
path->slots[i]++;
|
|
*level = i;
|
|
return 0;
|
|
} else {
|
|
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 = i + 1;
|
|
BUG_ON(ret);
|
|
}
|
|
}
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
* drop the reference count on the tree rooted at 'snap'. This traverses
|
|
* the tree freeing any blocks that have a ref count of zero after being
|
|
* decremented.
|
|
*/
|
|
int btrfs_drop_snapshot(struct btrfs_trans_handle *trans, struct btrfs_root
|
|
*root, struct buffer_head *snap)
|
|
{
|
|
int ret = 0;
|
|
int wret;
|
|
int level;
|
|
struct btrfs_path path;
|
|
int i;
|
|
int orig_level;
|
|
|
|
btrfs_init_path(&path);
|
|
|
|
level = btrfs_header_level(btrfs_buffer_header(snap));
|
|
orig_level = level;
|
|
path.nodes[level] = snap;
|
|
path.slots[level] = 0;
|
|
while(1) {
|
|
wret = walk_down_tree(trans, root, &path, &level);
|
|
if (wret > 0)
|
|
break;
|
|
if (wret < 0)
|
|
ret = wret;
|
|
|
|
wret = walk_up_tree(trans, root, &path, &level);
|
|
if (wret > 0)
|
|
break;
|
|
if (wret < 0)
|
|
ret = wret;
|
|
}
|
|
for (i = 0; i <= orig_level; i++) {
|
|
if (path.nodes[i]) {
|
|
btrfs_block_release(root, path.nodes[i]);
|
|
}
|
|
}
|
|
return ret;
|
|
}
|