From 7be5516fbf45b1d94d0e5bebca2e1c565f4ee3f1 Mon Sep 17 00:00:00 2001 From: Mark Harmstone Date: Tue, 13 Jan 2026 18:37:56 +0000 Subject: [PATCH] btrfs: fix missing fields in superblock backup with BLOCK_GROUP_TREE [ Upstream commit 1d8f69f453c2e8a2d99b158e58e02ed65031fa6d ] When the BLOCK_GROUP_TREE compat_ro flag is set, the extent root and csum root fields are getting missed. This is because EXTENT_TREE_V2 treated these differently, and when they were split off this special-casing was mistakenly assigned to BGT rather than the rump EXTENT_TREE_V2. There's no reason why the existence of the block group tree should mean that we don't record the details of the last commit's extent root and csum root. Fix the code in backup_super_roots() so that the correct check gets made. Fixes: 1c56ab991903 ("btrfs: separate BLOCK_GROUP_TREE compat RO flag from EXTENT_TREE_V2") Reviewed-by: Qu Wenruo Signed-off-by: Mark Harmstone Reviewed-by: David Sterba Signed-off-by: David Sterba Signed-off-by: Sasha Levin --- fs/btrfs/disk-io.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index 39fe4385ed36..93300c3fe0ca 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -1676,7 +1676,7 @@ static void backup_super_roots(struct btrfs_fs_info *info) btrfs_set_backup_chunk_root_level(root_backup, btrfs_header_level(info->chunk_root->node)); - if (!btrfs_fs_compat_ro(info, BLOCK_GROUP_TREE)) { + if (!btrfs_fs_incompat(info, EXTENT_TREE_V2)) { struct btrfs_root *extent_root = btrfs_extent_root(info, 0); struct btrfs_root *csum_root = btrfs_csum_root(info, 0);