[PATCH v2.1 2/3] btrfs-progs: check/original: Check and repair root item geneartion

[Qu Wenruo]

Add such ability to original mode to fix root generation mismatch, which
can be rejected by kernel.

Signed-off-by: Qu Wenruo <w...@suse.com>
---
 check/main.c | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/check/main.c b/check/main.c
index 98b07fcb58c8..ae3ce13e9466 100644
--- a/check/main.c
+++ b/check/main.c
@@ -3437,8 +3437,10 @@ static int check_fs_root(struct btrfs_root *root,
 {
        int ret = 0;
        int err = 0;
+       bool generation_err = false;
        int wret;
        int level;
+       u64 super_generation;
        struct btrfs_path path;
        struct shared_node root_node;
        struct root_record *rec;
@@ -3449,6 +3451,23 @@ static int check_fs_root(struct btrfs_root *root,
        struct unaligned_extent_rec_t *urec;
        struct unaligned_extent_rec_t *tmp;
 
+       super_generation = btrfs_super_generation(root->fs_info->super_copy);
+       if (btrfs_root_generation(root_item) > super_generation + 1) {
+               error(
+       "invalid generation for root %llu, have %llu expect (0, %llu]",
+                     root->root_key.objectid, btrfs_root_generation(root_item),
+                     super_generation + 1);
+               generation_err = true;
+               if (repair) {
+                       root->node->flags |= EXTENT_BAD_TRANSID;
+                       ret = recow_extent_buffer(root, root->node);
+                       if (!ret) {
+                               printf("Reset generation for root %llu\n",
+                                       root->root_key.objectid);
+                               generation_err = false;
+                       }
+               }
+       }
        /*
         * Reuse the corrupt_block cache tree to record corrupted tree block
         *
@@ -3597,6 +3616,8 @@ skip_walking:
 
        free_corrupt_blocks_tree(&corrupt_blocks);
        root->fs_info->corrupt_blocks = NULL;
+       if (!ret && generation_err)
+               ret = -1;
        return ret;
 }
 
-- 
2.22.0