reproducing steps:
mkfs.btrfs /dev/dm-2 -f
mount /dev/dm-2 /btrfs
umount /btrfs
btrfs check /dev/dm-2 --repair
mount /dev/dm-2 /btrfs
----
btrfs: mismatching generation and generation_v2 found in root item. This root
was probably mounted with an older kernel. Resetting all new fields.
----
btrfs-debug-tree shows change in uuid
< root data bytenr 29425664 level 0 dirid 0 refs 1 gen 43
< uuid 293596e8-7888-eb4c-9134-6df9db996fe5
Signed-off-by: Anand Jain <anand.j...@oracle.com>
---
root-tree.c | 13 +++++++++++++
1 file changed, 13 insertions(+)
diff --git a/root-tree.c b/root-tree.c
index c10d068..4454147 100644
--- a/root-tree.c
+++ b/root-tree.c
@@ -69,6 +69,7 @@ int btrfs_update_root(struct btrfs_trans_handle *trans,
struct btrfs_root
int ret;
int slot;
unsigned long ptr;
+ u32 old_size;
path = btrfs_alloc_path();
BUG_ON(!path);
@@ -79,6 +80,18 @@ 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);
+ /*
+ * 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));
+ }
write_extent_buffer(l, item, ptr, sizeof(*item));
btrfs_mark_buffer_dirty(path->nodes[0]);
out:
--
1.8.1.227.g44fe835
--
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