On Wed, 2008-07-09 at 14:43 -0400, Josef Bacik wrote:
> Hello,
>
> This patch makes it so btrfs can handle unlink's and truncates that are
> interrupted. On unlink/truncate an orphan item is added with the location of
> the inode. When the truncation/deletion is completed the orphan item is
> removed. If a crash happens in between the orphaned inodes are processed at
> root lookup time. This also catches the case where the inode deletion may have
> occured but the orphan item wasn't removed. Tested with a bunch of stuff to
> make sure everything is working. Thank you,
>
Fantastic, thanks Josef. A few comments below.
> d so it also defines (optimal)
> @@ -621,6 +625,10 @@ struct btrfs_root {
>
> /* the dirty list is only used by non-reference counted roots */
> struct list_head dirty_list;
> +
> + /* orphan crap */
Crap is worse than no comments at all ;)
>
> +int btrfs_insert_orphan_item(struct btrfs_trans_handle *trans,
> + struct btrfs_root *root, u64 offset,
> + struct btrfs_key *location)
> +{
> + struct btrfs_disk_key disk_key;
> + struct btrfs_dir_item *dir_item;
> + struct btrfs_path *path;
> + struct btrfs_key key;
> + struct extent_buffer *leaf;
> + int ret = 0;
> + u32 data_size;
> +
> + key.objectid = BTRFS_ORPHAN_OBJECTID;
> + btrfs_set_key_type(&key, BTRFS_ORPHAN_ITEM_KEY);
> + key.offset = offset;
> +
> + path = btrfs_alloc_path();
> + if (!path)
> + return -ENOMEM;
> +
> + data_size = sizeof(*dir_item);
> + dir_item = insert_with_overflow(trans, root, path, &key,
> + data_size, "", 0);
I thought your plan to move away from dir items would use a new item
type completely.
We only really need to store the objectid of the inode, which is already
encoded in the key offset field. So, you could try an 0 length item and
we can fix up any problems that result in the btree code (I think it'll
tolerate this).
> +int btrfs_orphan_add(struct btrfs_trans_handle *trans, struct inode *inode)
> +{
> + struct btrfs_root *root = BTRFS_I(inode)->root;
> + struct btrfs_key key;
> + int ret = 0;
> +
> + mutex_lock(&root->orphan_mutex);
This orphan mutex is going to serialize things pretty badly, since you
could be doing IO with it held. Could you please make this a spin lock
held only during list manipulation?
The inode i_mutex should protect us from inserting/removing the same
inode at the same time into the orphan index.
Thanks again, this is great.
-chris
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