btrfs: remove old unused commented out code

Remove code which has been #if0-ed out for a very long time and does not
seem to be related to current codebase anymore.

Signed-off-by: David Sterba <dsterba@suse.cz>

1 files changed, 0 insertions, 172 deletions

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 57122a5e8473..5ff52b644a60 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -3093,178 +3093,6 @@ out:
         return err;
 }
 
-#if 0
-/*
- * when truncating bytes in a file, it is possible to avoid reading
- * the leaves that contain only checksum items.  This can be the
- * majority of the IO required to delete a large file, but it must
- * be done carefully.
- *
- * The keys in the level just above the leaves are checked to make sure
- * the lowest key in a given leaf is a csum key, and starts at an offset
- * after the new  size.
- *
- * Then the key for the next leaf is checked to make sure it also has
- * a checksum item for the same file.  If it does, we know our target leaf
- * contains only checksum items, and it can be safely freed without reading
- * it.
- *
- * This is just an optimization targeted at large files.  It may do
- * nothing.  It will return 0 unless things went badly.
- */
-static noinline int drop_csum_leaves(struct btrfs_trans_handle *trans,
-                                     struct btrfs_root *root,
-                                     struct btrfs_path *path,
-                                     struct inode *inode, u64 new_size)
-{
-        struct btrfs_key key;
-        int ret;
-        int nritems;
-        struct btrfs_key found_key;
-        struct btrfs_key other_key;
-        struct btrfs_leaf_ref *ref;
-        u64 leaf_gen;
-        u64 leaf_start;
-
-        path->lowest_level = 1;
-        key.objectid = inode->i_ino;
-        key.type = BTRFS_CSUM_ITEM_KEY;
-        key.offset = new_size;
-again:
-        ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
-        if (ret < 0)
-                goto out;
-
-        if (path->nodes[1] == NULL) {
-                ret = 0;
-                goto out;
-        }
-        ret = 0;
-        btrfs_node_key_to_cpu(path->nodes[1], &found_key, path->slots[1]);
-        nritems = btrfs_header_nritems(path->nodes[1]);
-
-        if (!nritems)
-                goto out;
-
-        if (path->slots[1] >= nritems)
-                goto next_node;
-
-        /* did we find a key greater than anything we want to delete? */
-        if (found_key.objectid > inode->i_ino ||
-           (found_key.objectid == inode->i_ino && found_key.type > key.type))
-                goto out;
-
-        /* we check the next key in the node to make sure the leave contains
-         * only checksum items.  This comparison doesn't work if our
-         * leaf is the last one in the node
-         */
-        if (path->slots[1] + 1 >= nritems) {
-next_node:
-                /* search forward from the last key in the node, this
-                 * will bring us into the next node in the tree
-                 */
-                btrfs_node_key_to_cpu(path->nodes[1], &found_key, nritems - 1);
-
-                /* unlikely, but we inc below, so check to be safe */
-                if (found_key.offset == (u64)-1)
-                        goto out;
-
-                /* search_forward needs a path with locks held, do the
-                 * search again for the original key.  It is possible
-                 * this will race with a balance and return a path that
-                 * we could modify, but this drop is just an optimization
-                 * and is allowed to miss some leaves.
-                 */
-                btrfs_release_path(root, path);
-                found_key.offset++;
-
-                /* setup a max key for search_forward */
-                other_key.offset = (u64)-1;
-                other_key.type = key.type;
-                other_key.objectid = key.objectid;
-
-                path->keep_locks = 1;
-                ret = btrfs_search_forward(root, &found_key, &other_key,
-                                           path, 0, 0);
-                path->keep_locks = 0;
-                if (ret || found_key.objectid != key.objectid ||
-                    found_key.type != key.type) {
-                        ret = 0;
-                        goto out;
-                }
-
-                key.offset = found_key.offset;
-                btrfs_release_path(root, path);
-                cond_resched();
-                goto again;
-        }
-
-        /* we know there's one more slot after us in the tree,
-         * read that key so we can verify it is also a checksum item
-         */
-        btrfs_node_key_to_cpu(path->nodes[1], &other_key, path->slots[1] + 1);
-
-        if (found_key.objectid < inode->i_ino)
-                goto next_key;
-
-        if (found_key.type != key.type || found_key.offset < new_size)
-                goto next_key;
-
-        /*
-         * if the key for the next leaf isn't a csum key from this objectid,
-         * we can't be sure there aren't good items inside this leaf.
-         * Bail out
-         */
-        if (other_key.objectid != inode->i_ino || other_key.type != key.type)
-                goto out;
-
-        leaf_start = btrfs_node_blockptr(path->nodes[1], path->slots[1]);
-        leaf_gen = btrfs_node_ptr_generation(path->nodes[1], path->slots[1]);
-        /*
-         * it is safe to delete this leaf, it contains only
-         * csum items from this inode at an offset >= new_size
-         */
-        ret = btrfs_del_leaf(trans, root, path, leaf_start);
-        BUG_ON(ret);
-
-        if (root->ref_cows && leaf_gen < trans->transid) {
-                ref = btrfs_alloc_leaf_ref(root, 0);
-                if (ref) {
-                        ref->root_gen = root->root_key.offset;
-                        ref->bytenr = leaf_start;
-                        ref->owner = 0;
-                        ref->generation = leaf_gen;
-                        ref->nritems = 0;
-
-                        btrfs_sort_leaf_ref(ref);
-
-                        ret = btrfs_add_leaf_ref(root, ref, 0);
-                        WARN_ON(ret);
-                        btrfs_free_leaf_ref(root, ref);
-                } else {
-                        WARN_ON(1);
-                }
-        }
-next_key:
-        btrfs_release_path(root, path);
-
-        if (other_key.objectid == inode->i_ino &&
-            other_key.type == key.type && other_key.offset > key.offset) {
-                key.offset = other_key.offset;
-                cond_resched();
-                goto again;
-        }
-        ret = 0;
-out:
-        /* fixup any changes we've made to the path */
-        path->lowest_level = 0;
-        path->keep_locks = 0;
-        btrfs_release_path(root, path);
-        return ret;
-}
-
-#endif
-
 /*
  * this can truncate away extent items, csum items and directory items.
  * It starts at a high offset and removes keys until it can't find