Btrfs btree item manipulation.
This includes the helpers to actually insert, remove, extent, truncate
and do other basic operations on the btree items.
It also has helpers for walking forward and backward in the btree.
All metadata updates eventually hit this code.
Signed-off-by: Chris Mason <chris.mason@xxxxxxxxxx>
--- a/fs/btrfs/ctree.c 2009-01-08 10:04:14.659535797 -0500
+++ b/fs/btrfs/ctree.c 2009-01-08 09:59:41.600461904 -0500
@@ -463,6 +463,131 @@
}
/*
+ * this is used by the defrag code to go through all the
+ * leaves pointed to by a node and reallocate them so that
+ * disk order is close to key order
+ */
+int btrfs_realloc_node(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root, struct extent_buffer *parent,
+ int start_slot, int cache_only, u64 *last_ret,
+ struct btrfs_key *progress)
+{
+ struct extent_buffer *cur;
+ u64 blocknr;
+ u64 gen;
+ u64 search_start = *last_ret;
+ u64 last_block = 0;
+ u64 other;
+ u32 parent_nritems;
+ int end_slot;
+ int i;
+ int err = 0;
+ int parent_level;
+ int uptodate;
+ u32 blocksize;
+ int progress_passed = 0;
+ struct btrfs_disk_key disk_key;
+
+ parent_level = btrfs_header_level(parent);
+ if (cache_only && parent_level != 1)
+ return 0;
+
+ if (trans->transaction != root->fs_info->running_transaction)
+ WARN_ON(1);
+ if (trans->transid != root->fs_info->generation)
+ WARN_ON(1);
+
+ parent_nritems = btrfs_header_nritems(parent);
+ blocksize = btrfs_level_size(root, parent_level - 1);
+ end_slot = parent_nritems;
+
+ if (parent_nritems == 1)
+ return 0;
+
+ for (i = start_slot; i < end_slot; i++) {
+ int close = 1;
+
+ if (!parent->map_token) {
+ map_extent_buffer(parent,
+ btrfs_node_key_ptr_offset(i),
+ sizeof(struct btrfs_key_ptr),
+ &parent->map_token, &parent->kaddr,
+ &parent->map_start, &parent->map_len,
+ KM_USER1);
+ }
+ btrfs_node_key(parent, &disk_key, i);
+ if (!progress_passed && comp_keys(&disk_key, progress) < 0)
+ continue;
+
+ progress_passed = 1;
+ blocknr = btrfs_node_blockptr(parent, i);
+ gen = btrfs_node_ptr_generation(parent, i);
+ if (last_block == 0)
+ last_block = blocknr;
+
+ if (i > 0) {
+ other = btrfs_node_blockptr(parent, i - 1);
+ close = close_blocks(blocknr, other, blocksize);
+ }
+ if (!close && i < end_slot - 2) {
+ other = btrfs_node_blockptr(parent, i + 1);
+ close = close_blocks(blocknr, other, blocksize);
+ }
+ if (close) {
+ last_block = blocknr;
+ continue;
+ }
+ if (parent->map_token) {
+ unmap_extent_buffer(parent, parent->map_token,
+ KM_USER1);
+ parent->map_token = NULL;
+ }
+
+ cur = btrfs_find_tree_block(root, blocknr, blocksize);
+ if (cur)
+ uptodate = btrfs_buffer_uptodate(cur, gen);
+ else
+ uptodate = 0;
+ if (!cur || !uptodate) {
+ if (cache_only) {
+ free_extent_buffer(cur);
+ continue;
+ }
+ if (!cur) {
+ cur = read_tree_block(root, blocknr,
+ blocksize, gen);
+ } else if (!uptodate) {
+ btrfs_read_buffer(cur, gen);
+ }
+ }
+ if (search_start == 0)
+ search_start = last_block;
+
+ btrfs_tree_lock(cur);
+ err = __btrfs_cow_block(trans, root, cur, parent, i,
+ &cur, search_start,
+ min(16 * blocksize,
+ (end_slot - i) * blocksize), 0);
+ if (err) {
+ btrfs_tree_unlock(cur);
+ free_extent_buffer(cur);
+ break;
+ }
+ search_start = cur->start;
+ last_block = cur->start;
+ *last_ret = search_start;
+ btrfs_tree_unlock(cur);
+ free_extent_buffer(cur);
+ }
+ if (parent->map_token) {
+ unmap_extent_buffer(parent, parent->map_token,
+ KM_USER1);
+ parent->map_token = NULL;
+ }
+ return err;
+}
+
+/*
* The leaf data grows from end-to-front in the node.
* this returns the address of the start of the last item,
* which is the stop of the leaf data stack
@@ -1433,6 +1558,134 @@
return ret;
}
+int btrfs_merge_path(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root,
+ struct btrfs_key *node_keys,
+ u64 *nodes, int lowest_level)
+{
+ struct extent_buffer *eb;
+ struct extent_buffer *parent;
+ struct btrfs_key key;
+ u64 bytenr;
+ u64 generation;
+ u32 blocksize;
+ int level;
+ int slot;
+ int key_match;
+ int ret;
+
+ eb = btrfs_lock_root_node(root);
+ ret = btrfs_cow_block(trans, root, eb, NULL, 0, &eb, 0);
+ BUG_ON(ret);
+
+ parent = eb;
+ while (1) {
+ level = btrfs_header_level(parent);
+ if (level == 0 || level <= lowest_level)
+ break;
+
+ ret = bin_search(parent, &node_keys[lowest_level], level,
+ &slot);
+ if (ret && slot > 0)
+ slot--;
+
+ bytenr = btrfs_node_blockptr(parent, slot);
+ if (nodes[level - 1] == bytenr)
+ break;
+
+ blocksize = btrfs_level_size(root, level - 1);
+ generation = btrfs_node_ptr_generation(parent, slot);
+ btrfs_node_key_to_cpu(eb, &key, slot);
+ key_match = !memcmp(&key, &node_keys[level - 1], sizeof(key));
+
+ if (generation == trans->transid) {
+ eb = read_tree_block(root, bytenr, blocksize,
+ generation);
+ btrfs_tree_lock(eb);
+ }
+
+ /*
+ * if node keys match and node pointer hasn't been modified
+ * in the running transaction, we can merge the path. for
+ * blocks owened by reloc trees, the node pointer check is
+ * skipped, this is because these blocks are fully controlled
+ * by the space balance code, no one else can modify them.
+ */
+ if (!nodes[level - 1] || !key_match ||
+ (generation == trans->transid &&
+ btrfs_header_owner(eb) != BTRFS_TREE_RELOC_OBJECTID)) {
+ if (level == 1 || level == lowest_level + 1) {
+ if (generation == trans->transid) {
+ btrfs_tree_unlock(eb);
+ free_extent_buffer(eb);
+ }
+ break;
+ }
+
+ if (generation != trans->transid) {
+ eb = read_tree_block(root, bytenr, blocksize,
+ generation);
+ btrfs_tree_lock(eb);
+ }
+
+ ret = btrfs_cow_block(trans, root, eb, parent, slot,
+ &eb, 0);
+ BUG_ON(ret);
+
+ if (root->root_key.objectid ==
+ BTRFS_TREE_RELOC_OBJECTID) {
+ if (!nodes[level - 1]) {
+ nodes[level - 1] = eb->start;
+ memcpy(&node_keys[level - 1], &key,
+ sizeof(node_keys[0]));
+ } else {
+ WARN_ON(1);
+ }
+ }
+
+ btrfs_tree_unlock(parent);
+ free_extent_buffer(parent);
+ parent = eb;
+ continue;
+ }
+
+ btrfs_set_node_blockptr(parent, slot, nodes[level - 1]);
+ btrfs_set_node_ptr_generation(parent, slot, trans->transid);
+ btrfs_mark_buffer_dirty(parent);
+
+ ret = btrfs_inc_extent_ref(trans, root,
+ nodes[level - 1],
+ blocksize, parent->start,
+ btrfs_header_owner(parent),
+ btrfs_header_generation(parent),
+ level - 1);
+ BUG_ON(ret);
+
+ /*
+ * If the block was created in the running transaction,
+ * it's possible this is the last reference to it, so we
+ * should drop the subtree.
+ */
+ if (generation == trans->transid) {
+ ret = btrfs_drop_subtree(trans, root, eb, parent);
+ BUG_ON(ret);
+ btrfs_tree_unlock(eb);
+ free_extent_buffer(eb);
+ } else {
+ ret = btrfs_free_extent(trans, root, bytenr,
+ blocksize, parent->start,
+ btrfs_header_owner(parent),
+ btrfs_header_generation(parent),
+ level - 1, 1);
+ BUG_ON(ret);
+ }
+ break;
+ }
+ btrfs_tree_unlock(parent);
+ free_extent_buffer(parent);
+ return 0;
+}
+
/*
* adjust the pointers going up the tree, starting at level
* making sure the right key of each node is points to 'key'.
@@ -1464,6 +1717,40 @@
return ret;
}
+/*
+ * update item key.
+ *
+ * This function isn't completely safe. It's the caller's responsibility
+ * that the new key won't break the order
+ */
+int btrfs_set_item_key_safe(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root, struct btrfs_path *path,
+ struct btrfs_key *new_key)
+{
+ struct btrfs_disk_key disk_key;
+ struct extent_buffer *eb;
+ int slot;
+
+ eb = path->nodes[0];
+ slot = path->slots[0];
+ if (slot > 0) {
+ btrfs_item_key(eb, &disk_key, slot - 1);
+ if (comp_keys(&disk_key, new_key) >= 0)
+ return -1;
+ }
+ if (slot < btrfs_header_nritems(eb) - 1) {
+ btrfs_item_key(eb, &disk_key, slot + 1);
+ if (comp_keys(&disk_key, new_key) <= 0)
+ return -1;
+ }
+
+ btrfs_cpu_key_to_disk(&disk_key, new_key);
+ btrfs_set_item_key(eb, &disk_key, slot);
+ btrfs_mark_buffer_dirty(eb);
+ if (slot == 0)
+ fixup_low_keys(trans, root, path, &disk_key, 1);
+ return 0;
+}
/*
* try to push data from one node into the next node left in the
@@ -1593,6 +1880,85 @@
}
/*
+ * helper function to insert a new root level in the tree.
+ * A new node is allocated, and a single item is inserted to
+ * point to the existing root
+ *
+ * returns zero on success or < 0 on failure.
+ */
+static noinline int insert_new_root(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root,
+ struct btrfs_path *path, int level)
+{
+ u64 lower_gen;
+ struct extent_buffer *lower;
+ struct extent_buffer *c;
+ struct extent_buffer *old;
+ struct btrfs_disk_key lower_key;
+ int ret;
+
+ BUG_ON(path->nodes[level]);
+ BUG_ON(path->nodes[level-1] != root->node);
+
+ lower = path->nodes[level-1];
+ if (level == 1)
+ btrfs_item_key(lower, &lower_key, 0);
+ else
+ btrfs_node_key(lower, &lower_key, 0);
+
+ c = btrfs_alloc_free_block(trans, root, root->nodesize, 0,
+ root->root_key.objectid, trans->transid,
+ level, root->node->start, 0);
+ if (IS_ERR(c))
+ return PTR_ERR(c);
+
+ memset_extent_buffer(c, 0, 0, root->nodesize);
+ btrfs_set_header_nritems(c, 1);
+ btrfs_set_header_level(c, level);
+ btrfs_set_header_bytenr(c, c->start);
+ btrfs_set_header_generation(c, trans->transid);
+ btrfs_set_header_owner(c, root->root_key.objectid);
+
+ write_extent_buffer(c, root->fs_info->fsid,
+ (unsigned long)btrfs_header_fsid(c),
+ BTRFS_FSID_SIZE);
+
+ write_extent_buffer(c, root->fs_info->chunk_tree_uuid,
+ (unsigned long)btrfs_header_chunk_tree_uuid(c),
+ BTRFS_UUID_SIZE);
+
+ btrfs_set_node_key(c, &lower_key, 0);
+ btrfs_set_node_blockptr(c, 0, lower->start);
+ lower_gen = btrfs_header_generation(lower);
+ WARN_ON(lower_gen != trans->transid);
+
+ btrfs_set_node_ptr_generation(c, 0, lower_gen);
+
+ btrfs_mark_buffer_dirty(c);
+
+ spin_lock(&root->node_lock);
+ old = root->node;
+ root->node = c;
+ spin_unlock(&root->node_lock);
+
+ ret = btrfs_update_extent_ref(trans, root, lower->start,
+ lower->start, c->start,
+ root->root_key.objectid,
+ trans->transid, level - 1);
+ BUG_ON(ret);
+
+ /* the super has an extra ref to root->node */
+ free_extent_buffer(old);
+
+ add_root_to_dirty_list(root);
+ extent_buffer_get(c);
+ path->nodes[level] = c;
+ path->locks[level] = 1;
+ path->slots[level] = 0;
+ return 0;
+}
+
+/*
* worker function to insert a single pointer in a node.
* the node should have enough room for the pointer already
*
@@ -2401,41 +2767,1187 @@
}
/*
- * delete the pointer from a given node.
+ * This function splits a single item into two items,
+ * giving 'new_key' to the new item and splitting the
+ * old one at split_offset (from the start of the item).
*
- * the tree should have been previously balanced so the deletion does not
- * empty a node.
+ * The path may be released by this operation. After
+ * the split, the path is pointing to the old item. The
+ * new item is going to be in the same node as the old one.
+ *
+ * Note, the item being split must be smaller enough to live alone on
+ * a tree block with room for one extra struct btrfs_item
+ *
+ * This allows us to split the item in place, keeping a lock on the
+ * leaf the entire time.
*/
-static int del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root,
- struct btrfs_path *path, int level, int slot)
-{
- struct extent_buffer *parent = path->nodes[level];
+int btrfs_split_item(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root,
+ struct btrfs_path *path,
+ struct btrfs_key *new_key,
+ unsigned long split_offset)
+{
+ u32 item_size;
+ struct extent_buffer *leaf;
+ struct btrfs_key orig_key;
+ struct btrfs_item *item;
+ struct btrfs_item *new_item;
+ int ret = 0;
+ int slot;
u32 nritems;
+ u32 orig_offset;
+ struct btrfs_disk_key disk_key;
+ char *buf;
+
+ leaf = path->nodes[0];
+ btrfs_item_key_to_cpu(leaf, &orig_key, path->slots[0]);
+ if (btrfs_leaf_free_space(root, leaf) >= sizeof(struct btrfs_item))
+ goto split;
+
+ item_size = btrfs_item_size_nr(leaf, path->slots[0]);
+ btrfs_release_path(root, path);
+
+ path->search_for_split = 1;
+ path->keep_locks = 1;
+
+ ret = btrfs_search_slot(trans, root, &orig_key, path, 0, 1);
+ path->search_for_split = 0;
+
+ /* if our item isn't there or got smaller, return now */
+ if (ret != 0 || item_size != btrfs_item_size_nr(path->nodes[0],
+ path->slots[0])) {
+ path->keep_locks = 0;
+ return -EAGAIN;
+ }
+
+ ret = split_leaf(trans, root, &orig_key, path,
+ sizeof(struct btrfs_item), 1);
+ path->keep_locks = 0;
+ BUG_ON(ret);
+
+ leaf = path->nodes[0];
+ BUG_ON(btrfs_leaf_free_space(root, leaf) < sizeof(struct btrfs_item));
+
+split:
+ item = btrfs_item_nr(leaf, path->slots[0]);
+ orig_offset = btrfs_item_offset(leaf, item);
+ item_size = btrfs_item_size(leaf, item);
+
+
+ buf = kmalloc(item_size, GFP_NOFS);
+ read_extent_buffer(leaf, buf, btrfs_item_ptr_offset(leaf,
+ path->slots[0]), item_size);
+ slot = path->slots[0] + 1;
+ leaf = path->nodes[0];
+
+ nritems = btrfs_header_nritems(leaf);
+
+ if (slot != nritems) {
+ /* shift the items */
+ memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot + 1),
+ btrfs_item_nr_offset(slot),
+ (nritems - slot) * sizeof(struct btrfs_item));
+
+ }
+
+ btrfs_cpu_key_to_disk(&disk_key, new_key);
+ btrfs_set_item_key(leaf, &disk_key, slot);
+
+ new_item = btrfs_item_nr(leaf, slot);
+
+ btrfs_set_item_offset(leaf, new_item, orig_offset);
+ btrfs_set_item_size(leaf, new_item, item_size - split_offset);
+
+ btrfs_set_item_offset(leaf, item,
+ orig_offset + item_size - split_offset);
+ btrfs_set_item_size(leaf, item, split_offset);
+
+ btrfs_set_header_nritems(leaf, nritems + 1);
+
+ /* write the data for the start of the original item */
+ write_extent_buffer(leaf, buf,
+ btrfs_item_ptr_offset(leaf, path->slots[0]),
+ split_offset);
+
+ /* write the data for the new item */
+ write_extent_buffer(leaf, buf + split_offset,
+ btrfs_item_ptr_offset(leaf, slot),
+ item_size - split_offset);
+ btrfs_mark_buffer_dirty(leaf);
+
+ ret = 0;
+ if (btrfs_leaf_free_space(root, leaf) < 0) {
+ btrfs_print_leaf(root, leaf);
+ BUG();
+ }
+ kfree(buf);
+ return ret;
+}
+
+/*
+ * make the item pointed to by the path smaller. new_size indicates
+ * how small to make it, and from_end tells us if we just chop bytes
+ * off the end of the item or if we shift the item to chop bytes off
+ * the front.
+ */
+int btrfs_truncate_item(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root,
+ struct btrfs_path *path,
+ u32 new_size, int from_end)
+{
int ret = 0;
- int wret;
+ int slot;
+ int slot_orig;
+ struct extent_buffer *leaf;
+ struct btrfs_item *item;
+ u32 nritems;
+ unsigned int data_end;
+ unsigned int old_data_start;
+ unsigned int old_size;
+ unsigned int size_diff;
+ int i;
- nritems = btrfs_header_nritems(parent);
- if (slot != nritems - 1) {
- memmove_extent_buffer(parent,
- btrfs_node_key_ptr_offset(slot),
- btrfs_node_key_ptr_offset(slot + 1),
- sizeof(struct btrfs_key_ptr) *
- (nritems - slot - 1));
+ slot_orig = path->slots[0];
+ leaf = path->nodes[0];
+ slot = path->slots[0];
+
+ old_size = btrfs_item_size_nr(leaf, slot);
+ if (old_size == new_size)
+ return 0;
+
+ nritems = btrfs_header_nritems(leaf);
+ data_end = leaf_data_end(root, leaf);
+
+ old_data_start = btrfs_item_offset_nr(leaf, slot);
+
+ size_diff = old_size - new_size;
+
+ BUG_ON(slot < 0);
+ BUG_ON(slot >= nritems);
+
+ /*
+ * item0..itemN ... dataN.offset..dataN.size .. data0.size
+ */
+ /* first correct the data pointers */
+ for (i = slot; i < nritems; i++) {
+ u32 ioff;
+ item = btrfs_item_nr(leaf, i);
+
+ if (!leaf->map_token) {
+ map_extent_buffer(leaf, (unsigned long)item,
+ sizeof(struct btrfs_item),
+ &leaf->map_token, &leaf->kaddr,
+ &leaf->map_start, &leaf->map_len,
+ KM_USER1);
+ }
+
+ ioff = btrfs_item_offset(leaf, item);
+ btrfs_set_item_offset(leaf, item, ioff + size_diff);
}
- nritems--;
- btrfs_set_header_nritems(parent, nritems);
- if (nritems == 0 && parent == root->node) {
- BUG_ON(btrfs_header_level(root->node) != 1);
- /* just turn the root into a leaf and break */
- btrfs_set_header_level(root->node, 0);
- } else if (slot == 0) {
+
+ if (leaf->map_token) {
+ unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
+ leaf->map_token = NULL;
+ }
+
+ /* shift the data */
+ if (from_end) {
+ memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
+ data_end + size_diff, btrfs_leaf_data(leaf) +
+ data_end, old_data_start + new_size - data_end);
+ } else {
struct btrfs_disk_key disk_key;
+ u64 offset;
- btrfs_node_key(parent, &disk_key, 0);
- wret = fixup_low_keys(trans, root, path, &disk_key, level + 1);
- if (wret)
- ret = wret;
+ btrfs_item_key(leaf, &disk_key, slot);
+
+ if (btrfs_disk_key_type(&disk_key) == BTRFS_EXTENT_DATA_KEY) {
+ unsigned long ptr;
+ struct btrfs_file_extent_item *fi;
+
+ fi = btrfs_item_ptr(leaf, slot,
+ struct btrfs_file_extent_item);
+ fi = (struct btrfs_file_extent_item *)(
+ (unsigned long)fi - size_diff);
+
+ if (btrfs_file_extent_type(leaf, fi) ==
+ BTRFS_FILE_EXTENT_INLINE) {
+ ptr = btrfs_item_ptr_offset(leaf, slot);
+ memmove_extent_buffer(leaf, ptr,
+ (unsigned long)fi,
+ offsetof(struct btrfs_file_extent_item,
+ disk_bytenr));
+ }
+ }
+
+ memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
+ data_end + size_diff, btrfs_leaf_data(leaf) +
+ data_end, old_data_start - data_end);
+
+ offset = btrfs_disk_key_offset(&disk_key);
+ btrfs_set_disk_key_offset(&disk_key, offset + size_diff);
+ btrfs_set_item_key(leaf, &disk_key, slot);
+ if (slot == 0)
+ fixup_low_keys(trans, root, path, &disk_key, 1);
+ }
+
+ item = btrfs_item_nr(leaf, slot);
+ btrfs_set_item_size(leaf, item, new_size);
+ btrfs_mark_buffer_dirty(leaf);
+
+ ret = 0;
+ if (btrfs_leaf_free_space(root, leaf) < 0) {
+ btrfs_print_leaf(root, leaf);
+ BUG();
+ }
+ return ret;
+}
+
+/*
+ * make the item pointed to by the path bigger, data_size is the new size.
+ */
+int btrfs_extend_item(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root, struct btrfs_path *path,
+ u32 data_size)
+{
+ int ret = 0;
+ int slot;
+ int slot_orig;
+ struct extent_buffer *leaf;
+ struct btrfs_item *item;
+ u32 nritems;
+ unsigned int data_end;
+ unsigned int old_data;
+ unsigned int old_size;
+ int i;
+
+ slot_orig = path->slots[0];
+ leaf = path->nodes[0];
+
+ nritems = btrfs_header_nritems(leaf);
+ data_end = leaf_data_end(root, leaf);
+
+ if (btrfs_leaf_free_space(root, leaf) < data_size) {
+ btrfs_print_leaf(root, leaf);
+ BUG();
+ }
+ slot = path->slots[0];
+ old_data = btrfs_item_end_nr(leaf, slot);
+
+ BUG_ON(slot < 0);
+ if (slot >= nritems) {
+ btrfs_print_leaf(root, leaf);
+ printk(KERN_CRIT "slot %d too large, nritems %d\n",
+ slot, nritems);
+ BUG_ON(1);
+ }
+
+ /*
+ * item0..itemN ... dataN.offset..dataN.size .. data0.size
+ */
+ /* first correct the data pointers */
+ for (i = slot; i < nritems; i++) {
+ u32 ioff;
+ item = btrfs_item_nr(leaf, i);
+
+ if (!leaf->map_token) {
+ map_extent_buffer(leaf, (unsigned long)item,
+ sizeof(struct btrfs_item),
+ &leaf->map_token, &leaf->kaddr,
+ &leaf->map_start, &leaf->map_len,
+ KM_USER1);
+ }
+ ioff = btrfs_item_offset(leaf, item);
+ btrfs_set_item_offset(leaf, item, ioff - data_size);
+ }
+
+ if (leaf->map_token) {
+ unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
+ leaf->map_token = NULL;
+ }
+
+ /* shift the data */
+ memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
+ data_end - data_size, btrfs_leaf_data(leaf) +
+ data_end, old_data - data_end);
+
+ data_end = old_data;
+ old_size = btrfs_item_size_nr(leaf, slot);
+ item = btrfs_item_nr(leaf, slot);
+ btrfs_set_item_size(leaf, item, old_size + data_size);
+ btrfs_mark_buffer_dirty(leaf);
+
+ ret = 0;
+ if (btrfs_leaf_free_space(root, leaf) < 0) {
+ btrfs_print_leaf(root, leaf);
+ BUG();
}
- btrfs_mark_buffer_dirty(parent);
return ret;
}
+
+/*
+ * Given a key and some data, insert items into the tree.
+ * This does all the path init required, making room in the tree if needed.
+ * Returns the number of keys that were inserted.
+ */
+int btrfs_insert_some_items(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root,
+ struct btrfs_path *path,
+ struct btrfs_key *cpu_key, u32 *data_size,
+ int nr)
+{
+ struct extent_buffer *leaf;
+ struct btrfs_item *item;
+ int ret = 0;
+ int slot;
+ int i;
+ u32 nritems;
+ u32 total_data = 0;
+ u32 total_size = 0;
+ unsigned int data_end;
+ struct btrfs_disk_key disk_key;
+ struct btrfs_key found_key;
+
+ for (i = 0; i < nr; i++) {
+ if (total_size + data_size[i] + sizeof(struct btrfs_item) >
+ BTRFS_LEAF_DATA_SIZE(root)) {
+ break;
+ nr = i;
+ }
+ total_data += data_size[i];
+ total_size += data_size[i] + sizeof(struct btrfs_item);
+ }
+ BUG_ON(nr == 0);
+
+ ret = btrfs_search_slot(trans, root, cpu_key, path, total_size, 1);
+ if (ret == 0)
+ return -EEXIST;
+ if (ret < 0)
+ goto out;
+
+ leaf = path->nodes[0];
+
+ nritems = btrfs_header_nritems(leaf);
+ data_end = leaf_data_end(root, leaf);
+
+ if (btrfs_leaf_free_space(root, leaf) < total_size) {
+ for (i = nr; i >= 0; i--) {
+ total_data -= data_size[i];
+ total_size -= data_size[i] + sizeof(struct btrfs_item);
+ if (total_size < btrfs_leaf_free_space(root, leaf))
+ break;
+ }
+ nr = i;
+ }
+
+ slot = path->slots[0];
+ BUG_ON(slot < 0);
+
+ if (slot != nritems) {
+ unsigned int old_data = btrfs_item_end_nr(leaf, slot);
+
+ item = btrfs_item_nr(leaf, slot);
+ btrfs_item_key_to_cpu(leaf, &found_key, slot);
+
+ /* figure out how many keys we can insert in here */
+ total_data = data_size[0];
+ for (i = 1; i < nr; i++) {
+ if (comp_cpu_keys(&found_key, cpu_key + i) <= 0)
+ break;
+ total_data += data_size[i];
+ }
+ nr = i;
+
+ if (old_data < data_end) {
+ btrfs_print_leaf(root, leaf);
+ printk(KERN_CRIT "slot %d old_data %d data_end %d\n",
+ slot, old_data, data_end);
+ BUG_ON(1);
+ }
+ /*
+ * item0..itemN ... dataN.offset..dataN.size .. data0.size
+ */
+ /* first correct the data pointers */
+ WARN_ON(leaf->map_token);
+ for (i = slot; i < nritems; i++) {
+ u32 ioff;
+
+ item = btrfs_item_nr(leaf, i);
+ if (!leaf->map_token) {
+ map_extent_buffer(leaf, (unsigned long)item,
+ sizeof(struct btrfs_item),
+ &leaf->map_token, &leaf->kaddr,
+ &leaf->map_start, &leaf->map_len,
+ KM_USER1);
+ }
+
+ ioff = btrfs_item_offset(leaf, item);
+ btrfs_set_item_offset(leaf, item, ioff - total_data);
+ }
+ if (leaf->map_token) {
+ unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
+ leaf->map_token = NULL;
+ }
+
+ /* shift the items */
+ memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot + nr),
+ btrfs_item_nr_offset(slot),
+ (nritems - slot) * sizeof(struct btrfs_item));
+
+ /* shift the data */
+ memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
+ data_end - total_data, btrfs_leaf_data(leaf) +
+ data_end, old_data - data_end);
+ data_end = old_data;
+ } else {
+ /*
+ * this sucks but it has to be done, if we are inserting at
+ * the end of the leaf only insert 1 of the items, since we
+ * have no way of knowing whats on the next leaf and we'd have
+ * to drop our current locks to figure it out
+ */
+ nr = 1;
+ }
+
+ /* setup the item for the new data */
+ for (i = 0; i < nr; i++) {
+ btrfs_cpu_key_to_disk(&disk_key, cpu_key + i);
+ btrfs_set_item_key(leaf, &disk_key, slot + i);
+ item = btrfs_item_nr(leaf, slot + i);
+ btrfs_set_item_offset(leaf, item, data_end - data_size[i]);
+ data_end -= data_size[i];
+ btrfs_set_item_size(leaf, item, data_size[i]);
+ }
+ btrfs_set_header_nritems(leaf, nritems + nr);
+ btrfs_mark_buffer_dirty(leaf);
+
+ ret = 0;
+ if (slot == 0) {
+ btrfs_cpu_key_to_disk(&disk_key, cpu_key);
+ ret = fixup_low_keys(trans, root, path, &disk_key, 1);
+ }
+
+ if (btrfs_leaf_free_space(root, leaf) < 0) {
+ btrfs_print_leaf(root, leaf);
+ BUG();
+ }
+out:
+ if (!ret)
+ ret = nr;
+ return ret;
+}
+
+/*
+ * Given a key and some data, insert items into the tree.
+ * This does all the path init required, making room in the tree if needed.
+ */
+int btrfs_insert_empty_items(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root,
+ struct btrfs_path *path,
+ struct btrfs_key *cpu_key, u32 *data_size,
+ int nr)
+{
+ struct extent_buffer *leaf;
+ struct btrfs_item *item;
+ int ret = 0;
+ int slot;
+ int slot_orig;
+ int i;
+ u32 nritems;
+ u32 total_size = 0;
+ u32 total_data = 0;
+ unsigned int data_end;
+ struct btrfs_disk_key disk_key;
+
+ for (i = 0; i < nr; i++)
+ total_data += data_size[i];
+
+ total_size = total_data + (nr * sizeof(struct btrfs_item));
+ ret = btrfs_search_slot(trans, root, cpu_key, path, total_size, 1);
+ if (ret == 0)
+ return -EEXIST;
+ if (ret < 0)
+ goto out;
+
+ slot_orig = path->slots[0];
+ leaf = path->nodes[0];
+
+ nritems = btrfs_header_nritems(leaf);
+ data_end = leaf_data_end(root, leaf);
+
+ if (btrfs_leaf_free_space(root, leaf) < total_size) {
+ btrfs_print_leaf(root, leaf);
+ printk(KERN_CRIT "not enough freespace need %u have %d\n",
+ total_size, btrfs_leaf_free_space(root, leaf));
+ BUG();
+ }
+
+ slot = path->slots[0];
+ BUG_ON(slot < 0);
+
+ if (slot != nritems) {
+ unsigned int old_data = btrfs_item_end_nr(leaf, slot);
+
+ if (old_data < data_end) {
+ btrfs_print_leaf(root, leaf);
+ printk(KERN_CRIT "slot %d old_data %d data_end %d\n",
+ slot, old_data, data_end);
+ BUG_ON(1);
+ }
+ /*
+ * item0..itemN ... dataN.offset..dataN.size .. data0.size
+ */
+ /* first correct the data pointers */
+ WARN_ON(leaf->map_token);
+ for (i = slot; i < nritems; i++) {
+ u32 ioff;
+
+ item = btrfs_item_nr(leaf, i);
+ if (!leaf->map_token) {
+ map_extent_buffer(leaf, (unsigned long)item,
+ sizeof(struct btrfs_item),
+ &leaf->map_token, &leaf->kaddr,
+ &leaf->map_start, &leaf->map_len,
+ KM_USER1);
+ }
+
+ ioff = btrfs_item_offset(leaf, item);
+ btrfs_set_item_offset(leaf, item, ioff - total_data);
+ }
+ if (leaf->map_token) {
+ unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
+ leaf->map_token = NULL;
+ }
+
+ /* shift the items */
+ memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot + nr),
+ btrfs_item_nr_offset(slot),
+ (nritems - slot) * sizeof(struct btrfs_item));
+
+ /* shift the data */
+ memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
+ data_end - total_data, btrfs_leaf_data(leaf) +
+ data_end, old_data - data_end);
+ data_end = old_data;
+ }
+
+ /* setup the item for the new data */
+ for (i = 0; i < nr; i++) {
+ btrfs_cpu_key_to_disk(&disk_key, cpu_key + i);
+ btrfs_set_item_key(leaf, &disk_key, slot + i);
+ item = btrfs_item_nr(leaf, slot + i);
+ btrfs_set_item_offset(leaf, item, data_end - data_size[i]);
+ data_end -= data_size[i];
+ btrfs_set_item_size(leaf, item, data_size[i]);
+ }
+ btrfs_set_header_nritems(leaf, nritems + nr);
+ btrfs_mark_buffer_dirty(leaf);
+
+ ret = 0;
+ if (slot == 0) {
+ btrfs_cpu_key_to_disk(&disk_key, cpu_key);
+ ret = fixup_low_keys(trans, root, path, &disk_key, 1);
+ }
+
+ if (btrfs_leaf_free_space(root, leaf) < 0) {
+ btrfs_print_leaf(root, leaf);
+ BUG();
+ }
+out:
+ return ret;
+}
+
+/*
+ * Given a key and some data, insert an item into the tree.
+ * This does all the path init required, making room in the tree if needed.
+ */
+int btrfs_insert_item(struct btrfs_trans_handle *trans, struct btrfs_root
+ *root, struct btrfs_key *cpu_key, void *data, u32
+ data_size)
+{
+ int ret = 0;
+ struct btrfs_path *path;
+ struct extent_buffer *leaf;
+ unsigned long ptr;
+
+ path = btrfs_alloc_path();
+ BUG_ON(!path);
+ ret = btrfs_insert_empty_item(trans, root, path, cpu_key, data_size);
+ if (!ret) {
+ leaf = path->nodes[0];
+ ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
+ write_extent_buffer(leaf, data, ptr, data_size);
+ btrfs_mark_buffer_dirty(leaf);
+ }
+ btrfs_free_path(path);
+ return ret;
+}
+
+/*
+ * delete the pointer from a given node.
+ *
+ * the tree should have been previously balanced so the deletion does not
+ * empty a node.
+ */
+static int del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root,
+ struct btrfs_path *path, int level, int slot)
+{
+ struct extent_buffer *parent = path->nodes[level];
+ u32 nritems;
+ int ret = 0;
+ int wret;
+
+ nritems = btrfs_header_nritems(parent);
+ if (slot != nritems - 1) {
+ memmove_extent_buffer(parent,
+ btrfs_node_key_ptr_offset(slot),
+ btrfs_node_key_ptr_offset(slot + 1),
+ sizeof(struct btrfs_key_ptr) *
+ (nritems - slot - 1));
+ }
+ nritems--;
+ btrfs_set_header_nritems(parent, nritems);
+ if (nritems == 0 && parent == root->node) {
+ BUG_ON(btrfs_header_level(root->node) != 1);
+ /* just turn the root into a leaf and break */
+ btrfs_set_header_level(root->node, 0);
+ } else if (slot == 0) {
+ struct btrfs_disk_key disk_key;
+
+ btrfs_node_key(parent, &disk_key, 0);
+ wret = fixup_low_keys(trans, root, path, &disk_key, level + 1);
+ if (wret)
+ ret = wret;
+ }
+ btrfs_mark_buffer_dirty(parent);
+ return ret;
+}
+
+/*
+ * a helper function to delete the leaf pointed to by path->slots[1] and
+ * path->nodes[1]. bytenr is the node block pointer, but since the callers
+ * already know it, it is faster to have them pass it down than to
+ * read it out of the node again.
+ *
+ * This deletes the pointer in path->nodes[1] and frees the leaf
+ * block extent. zero is returned if it all worked out, < 0 otherwise.
+ *
+ * The path must have already been setup for deleting the leaf, including
+ * all the proper balancing. path->nodes[1] must be locked.
+ */
+noinline int btrfs_del_leaf(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root,
+ struct btrfs_path *path, u64 bytenr)
+{
+ int ret;
+ u64 root_gen = btrfs_header_generation(path->nodes[1]);
+
+ ret = del_ptr(trans, root, path, 1, path->slots[1]);
+ if (ret)
+ return ret;
+
+ ret = btrfs_free_extent(trans, root, bytenr,
+ btrfs_level_size(root, 0),
+ path->nodes[1]->start,
+ btrfs_header_owner(path->nodes[1]),
+ root_gen, 0, 1);
+ return ret;
+}
+/*
+ * delete the item at the leaf level in path. If that empties
+ * the leaf, remove it from the tree
+ */
+int btrfs_del_items(struct btrfs_trans_handle *trans, struct btrfs_root *root,
+ struct btrfs_path *path, int slot, int nr)
+{
+ struct extent_buffer *leaf;
+ struct btrfs_item *item;
+ int last_off;
+ int dsize = 0;
+ int ret = 0;
+ int wret;
+ int i;
+ u32 nritems;
+
+ leaf = path->nodes[0];
+ last_off = btrfs_item_offset_nr(leaf, slot + nr - 1);
+
+ for (i = 0; i < nr; i++)
+ dsize += btrfs_item_size_nr(leaf, slot + i);
+
+ nritems = btrfs_header_nritems(leaf);
+
+ if (slot + nr != nritems) {
+ int data_end = leaf_data_end(root, leaf);
+
+ memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
+ data_end + dsize,
+ btrfs_leaf_data(leaf) + data_end,
+ last_off - data_end);
+
+ for (i = slot + nr; i < nritems; i++) {
+ u32 ioff;
+
+ item = btrfs_item_nr(leaf, i);
+ if (!leaf->map_token) {
+ map_extent_buffer(leaf, (unsigned long)item,
+ sizeof(struct btrfs_item),
+ &leaf->map_token, &leaf->kaddr,
+ &leaf->map_start, &leaf->map_len,
+ KM_USER1);
+ }
+ ioff = btrfs_item_offset(leaf, item);
+ btrfs_set_item_offset(leaf, item, ioff + dsize);
+ }
+
+ if (leaf->map_token) {
+ unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
+ leaf->map_token = NULL;
+ }
+
+ memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot),
+ btrfs_item_nr_offset(slot + nr),
+ sizeof(struct btrfs_item) *
+ (nritems - slot - nr));
+ }
+ btrfs_set_header_nritems(leaf, nritems - nr);
+ nritems -= nr;
+
+ /* delete the leaf if we've emptied it */
+ if (nritems == 0) {
+ if (leaf == root->node) {
+ btrfs_set_header_level(leaf, 0);
+ } else {
+ ret = btrfs_del_leaf(trans, root, path, leaf->start);
+ BUG_ON(ret);
+ }
+ } else {
+ int used = leaf_space_used(leaf, 0, nritems);
+ if (slot == 0) {
+ struct btrfs_disk_key disk_key;
+
+ btrfs_item_key(leaf, &disk_key, 0);
+ wret = fixup_low_keys(trans, root, path,
+ &disk_key, 1);
+ if (wret)
+ ret = wret;
+ }
+
+ /* delete the leaf if it is mostly empty */
+ if (used < BTRFS_LEAF_DATA_SIZE(root) / 4) {
+ /* push_leaf_left fixes the path.
+ * make sure the path still points to our leaf
+ * for possible call to del_ptr below
+ */
+ slot = path->slots[1];
+ extent_buffer_get(leaf);
+
+ wret = push_leaf_left(trans, root, path, 1, 1);
+ if (wret < 0 && wret != -ENOSPC)
+ ret = wret;
+
+ if (path->nodes[0] == leaf &&
+ btrfs_header_nritems(leaf)) {
+ wret = push_leaf_right(trans, root, path, 1, 1);
+ if (wret < 0 && wret != -ENOSPC)
+ ret = wret;
+ }
+
+ if (btrfs_header_nritems(leaf) == 0) {
+ path->slots[1] = slot;
+ ret = btrfs_del_leaf(trans, root, path,
+ leaf->start);
+ BUG_ON(ret);
+ free_extent_buffer(leaf);
+ } else {
+ /* if we're still in the path, make sure
+ * we're dirty. Otherwise, one of the
+ * push_leaf functions must have already
+ * dirtied this buffer
+ */
+ if (path->nodes[0] == leaf)
+ btrfs_mark_buffer_dirty(leaf);
+ free_extent_buffer(leaf);
+ }
+ } else {
+ btrfs_mark_buffer_dirty(leaf);
+ }
+ }
+ return ret;
+}
+
+/*
+ * search the tree again to find a leaf with lesser keys
+ * returns 0 if it found something or 1 if there are no lesser leaves.
+ * returns < 0 on io errors.
+ *
+ * This may release the path, and so you may lose any locks held at the
+ * time you call it.
+ */
+int btrfs_prev_leaf(struct btrfs_root *root, struct btrfs_path *path)
+{
+ struct btrfs_key key;
+ struct btrfs_disk_key found_key;
+ int ret;
+
+ btrfs_item_key_to_cpu(path->nodes[0], &key, 0);
+
+ if (key.offset > 0)
+ key.offset--;
+ else if (key.type > 0)
+ key.type--;
+ else if (key.objectid > 0)
+ key.objectid--;
+ else
+ return 1;
+
+ btrfs_release_path(root, path);
+ ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
+ if (ret < 0)
+ return ret;
+ btrfs_item_key(path->nodes[0], &found_key, 0);
+ ret = comp_keys(&found_key, &key);
+ if (ret < 0)
+ return 0;
+ return 1;
+}
+
+/*
+ * A helper function to walk down the tree starting at min_key, and looking
+ * for nodes or leaves that are either in cache or have a minimum
+ * transaction id. This is used by the btree defrag code, and tree logging
+ *
+ * This does not cow, but it does stuff the starting key it finds back
+ * into min_key, so you can call btrfs_search_slot with cow=1 on the
+ * key and get a writable path.
+ *
+ * This does lock as it descends, and path->keep_locks should be set
+ * to 1 by the caller.
+ *
+ * This honors path->lowest_level to prevent descent past a given level
+ * of the tree.
+ *
+ * min_trans indicates the oldest transaction that you are interested
+ * in walking through. Any nodes or leaves older than min_trans are
+ * skipped over (without reading them).
+ *
+ * returns zero if something useful was found, < 0 on error and 1 if there
+ * was nothing in the tree that matched the search criteria.
+ */
+int btrfs_search_forward(struct btrfs_root *root, struct btrfs_key *min_key,
+ struct btrfs_key *max_key,
+ struct btrfs_path *path, int cache_only,
+ u64 min_trans)
+{
+ struct extent_buffer *cur;
+ struct btrfs_key found_key;
+ int slot;
+ int sret;
+ u32 nritems;
+ int level;
+ int ret = 1;
+
+ WARN_ON(!path->keep_locks);
+again:
+ cur = btrfs_lock_root_node(root);
+ level = btrfs_header_level(cur);
+ WARN_ON(path->nodes[level]);
+ path->nodes[level] = cur;
+ path->locks[level] = 1;
+
+ if (btrfs_header_generation(cur) < min_trans) {
+ ret = 1;
+ goto out;
+ }
+ while (1) {
+ nritems = btrfs_header_nritems(cur);
+ level = btrfs_header_level(cur);
+ sret = bin_search(cur, min_key, level, &slot);
+
+ /* at the lowest level, we're done, setup the path and exit */
+ if (level == path->lowest_level) {
+ if (slot >= nritems)
+ goto find_next_key;
+ ret = 0;
+ path->slots[level] = slot;
+ btrfs_item_key_to_cpu(cur, &found_key, slot);
+ goto out;
+ }
+ if (sret && slot > 0)
+ slot--;
+ /*
+ * check this node pointer against the cache_only and
+ * min_trans parameters. If it isn't in cache or is too
+ * old, skip to the next one.
+ */
+ while (slot < nritems) {
+ u64 blockptr;
+ u64 gen;
+ struct extent_buffer *tmp;
+ struct btrfs_disk_key disk_key;
+
+ blockptr = btrfs_node_blockptr(cur, slot);
+ gen = btrfs_node_ptr_generation(cur, slot);
+ if (gen < min_trans) {
+ slot++;
+ continue;
+ }
+ if (!cache_only)
+ break;
+
+ if (max_key) {
+ btrfs_node_key(cur, &disk_key, slot);
+ if (comp_keys(&disk_key, max_key) >= 0) {
+ ret = 1;
+ goto out;
+ }
+ }
+
+ tmp = btrfs_find_tree_block(root, blockptr,
+ btrfs_level_size(root, level - 1));
+
+ if (tmp && btrfs_buffer_uptodate(tmp, gen)) {
+ free_extent_buffer(tmp);
+ break;
+ }
+ if (tmp)
+ free_extent_buffer(tmp);
+ slot++;
+ }
+find_next_key:
+ /*
+ * we didn't find a candidate key in this node, walk forward
+ * and find another one
+ */
+ if (slot >= nritems) {
+ path->slots[level] = slot;
+ sret = btrfs_find_next_key(root, path, min_key, level,
+ cache_only, min_trans);
+ if (sret == 0) {
+ btrfs_release_path(root, path);
+ goto again;
+ } else {
+ goto out;
+ }
+ }
+ /* save our key for returning back */
+ btrfs_node_key_to_cpu(cur, &found_key, slot);
+ path->slots[level] = slot;
+ if (level == path->lowest_level) {
+ ret = 0;
+ unlock_up(path, level, 1);
+ goto out;
+ }
+ cur = read_node_slot(root, cur, slot);
+
+ btrfs_tree_lock(cur);
+ path->locks[level - 1] = 1;
+ path->nodes[level - 1] = cur;
+ unlock_up(path, level, 1);
+ }
+out:
+ if (ret == 0)
+ memcpy(min_key, &found_key, sizeof(found_key));
+ return ret;
+}
+
+/*
+ * this is similar to btrfs_next_leaf, but does not try to preserve
+ * and fixup the path. It looks for and returns the next key in the
+ * tree based on the current path and the cache_only and min_trans
+ * parameters.
+ *
+ * 0 is returned if another key is found, < 0 if there are any errors
+ * and 1 is returned if there are no higher keys in the tree
+ *
+ * path->keep_locks should be set to 1 on the search made before
+ * calling this function.
+ */
+int btrfs_find_next_key(struct btrfs_root *root, struct btrfs_path *path,
+ struct btrfs_key *key, int lowest_level,
+ int cache_only, u64 min_trans)
+{
+ int level = lowest_level;
+ int slot;
+ struct extent_buffer *c;
+
+ WARN_ON(!path->keep_locks);
+ while (level < BTRFS_MAX_LEVEL) {
+ if (!path->nodes[level])
+ return 1;
+
+ slot = path->slots[level] + 1;
+ c = path->nodes[level];
+next:
+ if (slot >= btrfs_header_nritems(c)) {
+ level++;
+ if (level == BTRFS_MAX_LEVEL)
+ return 1;
+ continue;
+ }
+ if (level == 0)
+ btrfs_item_key_to_cpu(c, key, slot);
+ else {
+ u64 blockptr = btrfs_node_blockptr(c, slot);
+ u64 gen = btrfs_node_ptr_generation(c, slot);
+
+ if (cache_only) {
+ struct extent_buffer *cur;
+ cur = btrfs_find_tree_block(root, blockptr,
+ btrfs_level_size(root, level - 1));
+ if (!cur || !btrfs_buffer_uptodate(cur, gen)) {
+ slot++;
+ if (cur)
+ free_extent_buffer(cur);
+ goto next;
+ }
+ free_extent_buffer(cur);
+ }
+ if (gen < min_trans) {
+ slot++;
+ goto next;
+ }
+ btrfs_node_key_to_cpu(c, key, slot);
+ }
+ return 0;
+ }
+ return 1;
+}
+
+/*
+ * search the tree again to find a leaf with greater keys
+ * returns 0 if it found something or 1 if there are no greater leaves.
+ * returns < 0 on io errors.
+ */
+int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path)
+{
+ int slot;
+ int level = 1;
+ struct extent_buffer *c;
+ struct extent_buffer *next = NULL;
+ struct btrfs_key key;
+ u32 nritems;
+ int ret;
+
+ nritems = btrfs_header_nritems(path->nodes[0]);
+ if (nritems == 0)
+ return 1;
+
+ btrfs_item_key_to_cpu(path->nodes[0], &key, nritems - 1);
+
+ btrfs_release_path(root, path);
+ path->keep_locks = 1;
+ ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
+ path->keep_locks = 0;
+
+ if (ret < 0)
+ return ret;
+
+ nritems = btrfs_header_nritems(path->nodes[0]);
+ /*
+ * by releasing the path above we dropped all our locks. A balance
+ * could have added more items next to the key that used to be
+ * at the very end of the block. So, check again here and
+ * advance the path if there are now more items available.
+ */
+ if (nritems > 0 && path->slots[0] < nritems - 1) {
+ path->slots[0]++;
+ goto done;
+ }
+
+ while (level < BTRFS_MAX_LEVEL) {
+ if (!path->nodes[level])
+ return 1;
+
+ slot = path->slots[level] + 1;
+ c = path->nodes[level];
+ if (slot >= btrfs_header_nritems(c)) {
+ level++;
+ if (level == BTRFS_MAX_LEVEL)
+ return 1;
+ continue;
+ }
+
+ if (next) {
+ btrfs_tree_unlock(next);
+ free_extent_buffer(next);
+ }
+
+ if (level == 1 && (path->locks[1] || path->skip_locking) &&
+ path->reada)
+ reada_for_search(root, path, level, slot, 0);
+
+ next = read_node_slot(root, c, slot);
+ if (!path->skip_locking) {
+ WARN_ON(!btrfs_tree_locked(c));
+ btrfs_tree_lock(next);
+ }
+ break;
+ }
+ path->slots[level] = slot;
+ while (1) {
+ level--;
+ c = path->nodes[level];
+ if (path->locks[level])
+ btrfs_tree_unlock(c);
+ free_extent_buffer(c);
+ path->nodes[level] = next;
+ path->slots[level] = 0;
+ if (!path->skip_locking)
+ path->locks[level] = 1;
+ if (!level)
+ break;
+ if (level == 1 && path->locks[1] && path->reada)
+ reada_for_search(root, path, level, slot, 0);
+ next = read_node_slot(root, next, 0);
+ if (!path->skip_locking) {
+ WARN_ON(!btrfs_tree_locked(path->nodes[level]));
+ btrfs_tree_lock(next);
+ }
+ }
+done:
+ unlock_up(path, 0, 1);
+ return 0;
+}
+
+/*
+ * this uses btrfs_prev_leaf to walk backwards in the tree, and keeps
+ * searching until it gets past min_objectid or finds an item of 'type'
+ *
+ * returns 0 if something is found, 1 if nothing was found and < 0 on error
+ */
+int btrfs_previous_item(struct btrfs_root *root,
+ struct btrfs_path *path, u64 min_objectid,
+ int type)
+{
+ struct btrfs_key found_key;
+ struct extent_buffer *leaf;
+ u32 nritems;
+ int ret;
+
+ while (1) {
+ if (path->slots[0] == 0) {
+ ret = btrfs_prev_leaf(root, path);
+ if (ret != 0)
+ return ret;
+ } else {
+ path->slots[0]--;
+ }
+ leaf = path->nodes[0];
+ nritems = btrfs_header_nritems(leaf);
+ if (nritems == 0)
+ return 1;
+ if (path->slots[0] == nritems)
+ path->slots[0]--;
+
+ btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
+ if (found_key.type == type)
+ return 0;
+ if (found_key.objectid < min_objectid)
+ break;
+ if (found_key.objectid == min_objectid &&
+ found_key.type < type)
+ break;
+ }
+ return 1;
+}
--
To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
