Hi Mark,
While reading 3/3 I stumbled across one more thing in this one:
On 05.04.2012 22:09, Mark Fasheh wrote:
> +int btrfs_find_one_extref(struct btrfs_root *root, u64 inode_objectid,
> + u64 start_off, struct btrfs_path *path,
> + struct btrfs_inode_extref **ret_ref, u64 *found_off)
> +{
> + int ret, slot;
> + struct btrfs_key key, found_key;
> + struct btrfs_inode_extref *ref;
> + struct extent_buffer *leaf;
> + struct btrfs_item *item;
> + unsigned long ptr;
>
> -/*
> - * There are a few corners where the link count of the file can't
> - * be properly maintained during replay. So, instead of adding
> - * lots of complexity to the log code, we just scan the backrefs
> - * for any file that has been through replay.
> - *
> - * The scan will update the link count on the inode to reflect the
> - * number of back refs found. If it goes down to zero, the iput
> - * will free the inode.
> - */
> -static noinline int fixup_inode_link_count(struct btrfs_trans_handle *trans,
> - struct btrfs_root *root,
> - struct inode *inode)
> + key.objectid = inode_objectid;
> + btrfs_set_key_type(&key, BTRFS_INODE_EXTREF_KEY);
> + key.offset = start_off;
> +
> + ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
> + if (ret < 0)
> + goto out;
> +
> + while (1) {
> + leaf = path->nodes[0];
> + slot = path->slots[0];
> + if (slot >= btrfs_header_nritems(leaf)) {
> + /*
> + * If the item at offset is not found,
> + * btrfs_search_slot will point us to the slot
> + * where it should be inserted. In our case
> + * that will be the slot directly before the
> + * next INODE_REF_KEY_V2 item. In the case
> + * that we're pointing to the last slot in a
> + * leaf, we must move one leaf over.
> + */
> + ret = btrfs_next_leaf(root, path);
> + if (ret) {
> + if (ret >= 1)
> + ret = -ENOENT;
> + break;
> + }
> + continue;
> + }
> +
> + item = btrfs_item_nr(leaf, slot);
> + btrfs_item_key_to_cpu(leaf, &found_key, slot);
> +
> + /*
> + * Check that we're still looking at an extended ref key for
> + * this particular objectid. If we have different
> + * objectid or type then there are no more to be found
> + * in the tree and we can exit.
> + */
> + ret = -ENOENT;
> + if (found_key.objectid != inode_objectid)
> + break;
> + if (btrfs_key_type(&found_key) != BTRFS_INODE_EXTREF_KEY)
> + break;
> +
> + ret = 0;
> + ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
> + ref = (struct btrfs_inode_extref *)ptr;
> + *ret_ref = ref;
> + if (found_off)
> + *found_off = found_key.offset + 1;
^^^
It's evil to call it "found offset" an then return one larger than the
offset found. No caller would ever expect this.
> + break;
> + }
> +
> +out:
> + return ret;
> +}
> +
> +static int count_inode_extrefs(struct btrfs_root *root,
> + struct inode *inode, struct btrfs_path *path)
> +{
> + int ret;
> + unsigned int nlink = 0;
> + u64 inode_objectid = btrfs_ino(inode);
> + u64 offset = 0;
> + struct btrfs_inode_extref *ref;
> +
> + while (1) {
> + ret = btrfs_find_one_extref(root, inode_objectid, offset, path,
> + &ref, &offset);
> + if (ret)
> + break;
> +
> + nlink++;
> + offset++;
^^^^^^^^
Huh. See? The caller expected to get the offset found from
btrfs_find_one_extref. As it stands you might be missing the very next key.
> + }
> +
> + return nlink;
> +}
-Jan
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