Btrfs: reference counts on data extents
Signed-off-by: Chris Mason <chris.mason@oracle.com>
This commit is contained in:
Chris Mason
David Woodhouse
parent
dee26a9f7a
commit
6407bf6d7c
@ -8,7 +8,10 @@
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* Add block mapping tree (simple dm layer)
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* Add simple tree locking (semaphore per tree)
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* Make allocator smarter
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* make level a field in header
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* add a block group to struct inode
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* Make directory hashing work on 32 bit
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* Make sure nobh stuff is working properly for cows
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* Do actual block accounting
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* Check compat and incompat flags on the inode
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* Add virtual filesystems, mountable snapshots
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@ -9,10 +9,11 @@ struct btrfs_transaction;
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#define BTRFS_MAGIC "_BtRfS_M"
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#define BTRFS_ROOT_TREE_OBJECTID 1
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#define BTRFS_EXTENT_TREE_OBJECTID 2
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#define BTRFS_INODE_MAP_OBJECTID 3
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#define BTRFS_FS_TREE_OBJECTID 4
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#define BTRFS_ROOT_TREE_OBJECTID 1ULL
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#define BTRFS_EXTENT_TREE_OBJECTID 2ULL
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#define BTRFS_INODE_MAP_OBJECTID 3ULL
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#define BTRFS_FS_TREE_OBJECTID 4ULL
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#define BTRFS_FIRST_FREE_OBJECTID 5ULL
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/*
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* we can actually store much bigger names, but lets not confuse the rest
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@ -13,7 +13,7 @@ static int del_pending_extents(struct btrfs_trans_handle *trans, struct
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btrfs_root *extent_root);
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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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*root, u64 blocknr, u64 num_blocks)
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{
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struct btrfs_path path;
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int ret;
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@ -29,7 +29,7 @@ static int inc_block_ref(struct btrfs_trans_handle *trans, struct btrfs_root
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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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key.offset = num_blocks;
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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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@ -48,7 +48,7 @@ static int inc_block_ref(struct btrfs_trans_handle *trans, struct btrfs_root
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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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*root, u64 blocknr, u64 num_blocks, u32 *refs)
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{
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struct btrfs_path path;
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int ret;
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@ -57,7 +57,7 @@ static int lookup_block_ref(struct btrfs_trans_handle *trans, struct btrfs_root
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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.offset = num_blocks;
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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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@ -76,17 +76,34 @@ int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
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{
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u64 blocknr;
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struct btrfs_node *buf_node;
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struct btrfs_leaf *buf_leaf;
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struct btrfs_disk_key *key;
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struct btrfs_file_extent_item *fi;
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int i;
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int leaf;
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int ret;
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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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leaf = btrfs_is_leaf(buf_node);
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buf_leaf = btrfs_buffer_leaf(buf);
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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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if (leaf) {
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key = &buf_leaf->items[i].key;
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if (btrfs_disk_key_type(key) != BTRFS_EXTENT_DATA_KEY)
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continue;
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fi = btrfs_item_ptr(buf_leaf, i,
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struct btrfs_file_extent_item);
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ret = inc_block_ref(trans, root,
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btrfs_file_extent_disk_blocknr(fi),
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btrfs_file_extent_disk_num_blocks(fi));
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BUG_ON(ret);
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} else {
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blocknr = btrfs_node_blockptr(buf_node, i);
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ret = inc_block_ref(trans, root, blocknr, 1);
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BUG_ON(ret);
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}
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}
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return 0;
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}
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@ -469,6 +486,37 @@ struct buffer_head *btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
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return buf;
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}
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static int drop_leaf_ref(struct btrfs_trans_handle *trans,
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struct btrfs_root *root, struct buffer_head *cur)
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{
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struct btrfs_disk_key *key;
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struct btrfs_leaf *leaf;
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struct btrfs_file_extent_item *fi;
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int i;
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int nritems;
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int ret;
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BUG_ON(!btrfs_is_leaf(btrfs_buffer_node(cur)));
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leaf = btrfs_buffer_leaf(cur);
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nritems = btrfs_header_nritems(&leaf->header);
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for (i = 0; i < nritems; i++) {
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key = &leaf->items[i].key;
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if (btrfs_disk_key_type(key) != BTRFS_EXTENT_DATA_KEY)
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continue;
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fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
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/*
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* FIXME make sure to insert a trans record that
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* repeats the snapshot del on crash
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*/
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ret = btrfs_free_extent(trans, root,
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btrfs_file_extent_disk_blocknr(fi),
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btrfs_file_extent_disk_num_blocks(fi),
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0);
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BUG_ON(ret);
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}
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return 0;
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}
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/*
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* helper function for drop_snapshot, this walks down the tree dropping ref
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* counts as it goes.
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@ -483,28 +531,33 @@ static int walk_down_tree(struct btrfs_trans_handle *trans, struct btrfs_root
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u32 refs;
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ret = lookup_block_ref(trans, root, path->nodes[*level]->b_blocknr,
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&refs);
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1, &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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/*
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* walk down to the last node level and free all the leaves
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*/
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while(*level > 0) {
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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(btrfs_buffer_header(cur)))
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break;
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if (*level == 0) {
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ret = drop_leaf_ref(trans, root, cur);
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BUG_ON(ret);
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break;
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}
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blocknr = btrfs_node_blockptr(btrfs_buffer_node(cur),
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path->slots[*level]);
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ret = lookup_block_ref(trans, root, blocknr, &refs);
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if (refs != 1 || *level == 1) {
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ret = lookup_block_ref(trans, root, blocknr, 1, &refs);
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BUG_ON(ret);
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if (refs != 1) {
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path->slots[*level]++;
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ret = btrfs_free_extent(trans, root, blocknr, 1, 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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@ -513,8 +566,8 @@ static int walk_down_tree(struct btrfs_trans_handle *trans, struct btrfs_root
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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(trans, root, path->nodes[*level]->b_blocknr,
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1, 1);
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ret = btrfs_free_extent(trans, root,
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path->nodes[*level]->b_blocknr, 1, 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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@ -544,10 +597,10 @@ static int walk_up_tree(struct btrfs_trans_handle *trans, struct btrfs_root
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ret = btrfs_free_extent(trans, root,
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path->nodes[*level]->b_blocknr,
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1, 1);
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BUG_ON(ret);
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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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@ -25,6 +25,7 @@ int btrfs_find_free_objectid(struct btrfs_trans_handle *trans,
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if (fs_root->fs_info->last_inode_alloc_dirid == dirid)
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search_start = fs_root->fs_info->last_inode_alloc;
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search_start = max(search_start, BTRFS_FIRST_FREE_OBJECTID);
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search_key.objectid = search_start;
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search_key.flags = 0;
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btrfs_set_key_type(&search_key, BTRFS_INODE_MAP_ITEM_KEY);
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@ -700,7 +700,7 @@ out:
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static int btrfs_prepare_write(struct file *file, struct page *page,
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unsigned from, unsigned to)
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{
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return block_prepare_write(page, from, to, btrfs_get_block);
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return nobh_prepare_write(page, from, to, btrfs_get_block);
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}
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static void btrfs_write_super(struct super_block *sb)
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@ -721,7 +721,7 @@ static int btrfs_readpages(struct file *file, struct address_space *mapping,
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static int btrfs_writepage(struct page *page, struct writeback_control *wbc)
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{
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return block_write_full_page(page, btrfs_get_block, wbc);
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return nobh_writepage(page, btrfs_get_block, wbc);
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}
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static int btrfs_get_sb(struct file_system_type *fs_type,
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@ -768,7 +768,7 @@ static struct address_space_operations btrfs_aops = {
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.writepage = btrfs_writepage,
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.sync_page = block_sync_page,
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.prepare_write = btrfs_prepare_write,
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.commit_write = generic_commit_write,
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.commit_write = nobh_commit_write,
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};
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static struct inode_operations btrfs_file_inode_operations = {
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