This addresses the same issue as did:
2bd1169 btrfs-progs: root_item generation_v2 is out of sync after btrfsck
but rather than optionally updating generation_v2 based
on the size of the existing item, increase the size of the
item as needed, and unconditionally set generation_v2.
This matches the kernel code, and keeping things in sync is a
Good Thing.
Signed-off-by: Eric Sandeen <sand...@redhat.com>
---
kdave - since you already had Anand's patch on the integration
branch, I dunno if you want to add this on top, or just replace
it with a similar patch to this, up to you.
Thanks!
-Eric
diff --git a/root-tree.c b/root-tree.c
index 1823918..902d75d 100644
--- a/root-tree.c
+++ b/root-tree.c
@@ -69,7 +69,7 @@ int btrfs_update_root(struct btrfs_trans_handle *trans,
struct btrfs_root
int ret;
int slot;
unsigned long ptr;
- u32 old_size;
+ u32 old_len;
path = btrfs_alloc_path();
BUG_ON(!path);
@@ -80,18 +80,42 @@ int btrfs_update_root(struct btrfs_trans_handle *trans,
struct btrfs_root
l = path->nodes[0];
slot = path->slots[0];
ptr = btrfs_item_ptr_offset(l, slot);
+ old_len = btrfs_item_size_nr(l, slot);
+
/*
- * If the btrfs-progs is newer and kernel is at
- * generation_v1 then we don't touch v2 items
- * otherwise when kernel is at same or greater
- * version compared with btrfs-progs then update
- * the needed
- */
- old_size = btrfs_item_size_nr(l, slot);
- if (old_size >= sizeof(*item)) {
- btrfs_set_root_generation_v2(item,
- btrfs_root_generation(item));
+ * If this is the first time we update the root item which originated
+ * from an older kernel, we need to enlarge the item size to make room
+ * for the added fields.
+ */
+ if (old_len < sizeof(*item)) {
+ btrfs_release_path(root, path);
+ ret = btrfs_search_slot(trans, root, key, path,
+ -1, 1);
+ if (ret < 0) {
+ goto out;
+ }
+
+ ret = btrfs_del_item(trans, root, path);
+ if (ret < 0) {
+ goto out;
+ }
+ btrfs_release_path(root, path);
+ ret = btrfs_insert_empty_item(trans, root, path,
+ key, sizeof(*item));
+ if (ret < 0) {
+ goto out;
+ }
+ l = path->nodes[0];
+ slot = path->slots[0];
+ ptr = btrfs_item_ptr_offset(l, slot);
}
+
+ /*
+ * Update generation_v2 so at the next mount we know the new root
+ * fields are valid.
+ */
+ btrfs_set_root_generation_v2(item, btrfs_root_generation(item));
+
write_extent_buffer(l, item, ptr, sizeof(*item));
btrfs_mark_buffer_dirty(path->nodes[0]);
out:
--
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