Btrfs-progs: fsck: force to udate tree root for some cases

commit roots won't update root item in tree root if it finds
updated root's bytenr is same as before.

However, this is not right for fsck, we need update tree root in
the following case:

1.overwrite previous root node.

2.reinit reloc data tree, this is because we skip pin relo data
 tree before which means we can allocate same block as before.

Fix this by updating tree root ourselves for the above cases.

Signed-off-by: Wang Shilong <wangsl.fnst@cn.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Chris Mason <clm@fb.com>

1 files changed, 22 insertions, 1 deletions

diff --git a/cmds-check.c b/cmds-check.c
index 4b2a8f01..ae611d1d 100644
--- a/cmds-check.c
+++ b/cmds-check.c
@@ -5906,6 +5906,7 @@ static int btrfs_fsck_reinit_root(struct btrfs_trans_handle *trans,
 	struct extent_buffer *c;
 	struct extent_buffer *old = root->node;
 	int level;
+	int ret;
 	struct btrfs_disk_key disk_key = {0,0,0};
 
 	level = 0;
@@ -5922,6 +5923,7 @@ static int btrfs_fsck_reinit_root(struct btrfs_trans_handle *trans,
 	if (IS_ERR(c)) {
 		c = old;
 		extent_buffer_get(c);
+		overwrite = 1;
 	}
 init:
 	memset_extent_buffer(c, 0, 0, sizeof(struct btrfs_header));
@@ -5939,7 +5941,26 @@ init:
 			    BTRFS_UUID_SIZE);
 
 	btrfs_mark_buffer_dirty(c);
-
+	/*
+	 * this case can happen in the following case:
+	 *
+	 * 1.overwrite previous root.
+	 *
+	 * 2.reinit reloc data root, this is because we skip pin
+	 * down reloc data tree before which means we can allocate
+	 * same block bytenr here.
+	 */
+	if (old->start == c->start) {
+		btrfs_set_root_generation(&root->root_item,
+					  trans->transid);
+		root->root_item.level = btrfs_header_level(root->node);
+		ret = btrfs_update_root(trans, root->fs_info->tree_root,
+					&root->root_key, &root->root_item);
+		if (ret) {
+			free_extent_buffer(c);
+			return ret;
+		}
+	}
 	free_extent_buffer(old);
 	root->node = c;
 	add_root_to_dirty_list(root);