On Tue, Mar 10, 2015 at 10:15:44PM -0400, Josef Bacik wrote:
> Dave could hit this assert consistently running btrfs/078. This is because
> when we update the block groups we could truncate the free space, which would
> try to delete the csums for that range and dirty the csum root. For this to
> happen we have to have already written out the csum root so it's kind of hard to
> hit this case. This patch fixes this by changing the logic to only write the
> dirty block groups if the dirty_cowonly_roots list is empty. This will get us
> the same effect as before since we add the extent root last, and will cover the
> case that we dirty some other root again but not the extent root. Thanks,
I know this fix the bug, but the changelog doesn't tell me that --
why we still got oops while turning down csum for free space inode?
Someone else get other trees dirty?
Thanks,
-liubo
>
> Reported-by: David Sterba <dsterba@xxxxxxx>
> Signed-off-by: Josef Bacik <jbacik@xxxxxx>
> ---
> V2->V3: Actually fix the bug. Move the write dirty bgs stuff out of the update
> cowonly roots, then just check if we dirtied roots again and do the whole thing
> over again.
>
> fs/btrfs/transaction.c | 34 ++++++++++++++++++----------------
> 1 file changed, 18 insertions(+), 16 deletions(-)
>
> diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
> index 038fcf6..a703131 100644
> --- a/fs/btrfs/transaction.c
> +++ b/fs/btrfs/transaction.c
> @@ -1023,7 +1023,6 @@ static int update_cowonly_root(struct btrfs_trans_handle *trans,
> u64 old_root_bytenr;
> u64 old_root_used;
> struct btrfs_root *tree_root = root->fs_info->tree_root;
> - bool extent_root = (root->objectid == BTRFS_EXTENT_TREE_OBJECTID);
>
> old_root_used = btrfs_root_used(&root->root_item);
> btrfs_write_dirty_block_groups(trans, root);
> @@ -1031,9 +1030,7 @@ static int update_cowonly_root(struct btrfs_trans_handle *trans,
> while (1) {
> old_root_bytenr = btrfs_root_bytenr(&root->root_item);
> if (old_root_bytenr == root->node->start &&
> - old_root_used == btrfs_root_used(&root->root_item) &&
> - (!extent_root ||
> - list_empty(&trans->transaction->dirty_bgs)))
> + old_root_used == btrfs_root_used(&root->root_item))
> break;
>
> btrfs_set_root_node(&root->root_item, root->node);
> @@ -1044,17 +1041,6 @@ static int update_cowonly_root(struct btrfs_trans_handle *trans,
> return ret;
>
> old_root_used = btrfs_root_used(&root->root_item);
> - if (extent_root) {
> - ret = btrfs_write_dirty_block_groups(trans, root);
> - if (ret)
> - return ret;
> - }
> - ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
> - if (ret)
> - return ret;
> - ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
> - if (ret)
> - return ret;
> }
>
> return 0;
> @@ -1071,6 +1057,7 @@ static noinline int commit_cowonly_roots(struct btrfs_trans_handle *trans,
> struct btrfs_root *root)
> {
> struct btrfs_fs_info *fs_info = root->fs_info;
> + struct list_head *dirty_bgs = &trans->transaction->dirty_bgs;
> struct list_head *next;
> struct extent_buffer *eb;
> int ret;
> @@ -1102,7 +1089,7 @@ static noinline int commit_cowonly_roots(struct btrfs_trans_handle *trans,
> ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
> if (ret)
> return ret;
> -
> +again:
> while (!list_empty(&fs_info->dirty_cowonly_roots)) {
> next = fs_info->dirty_cowonly_roots.next;
> list_del_init(next);
> @@ -1115,8 +1102,23 @@ static noinline int commit_cowonly_roots(struct btrfs_trans_handle *trans,
> ret = update_cowonly_root(trans, root);
> if (ret)
> return ret;
> + ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
> + if (ret)
> + return ret;
> }
>
> + while (!list_empty(dirty_bgs)) {
> + ret = btrfs_write_dirty_block_groups(trans, root);
> + if (ret)
> + return ret;
> + ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
> + if (ret)
> + return ret;
> + }
> +
> + if (!list_empty(&fs_info->dirty_cowonly_roots))
> + goto again;
> +
> list_add_tail(&fs_info->extent_root->dirty_list,
> &trans->transaction->switch_commits);
> btrfs_after_dev_replace_commit(fs_info);
> --
> 1.9.3
>
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