On 2018年01月29日 21:53, Nikolay Borisov wrote:
> Running generic/019 with qgroups on the scratch device enabled is
> almost guaranteed to trigger the BUG_ON in btrfs_free_tree_block. It's
> supposed to trigger only on -ENOMEM, in reality, however, it's possible
> to get -EIO from btrfs_qgroup_trace_extent_post. This function just
> finds the roots of the extent being tracked and sets the qrecord->old_roots
> list. If this operation fails nothing critical happens except the
> quota accounting can be considered wrong. In such case just set the
> INCONSISTENT flag for the quota and print a warning, rather than
> killing off the system. Additionally, it's possible to trigger a BUG_ON
> in btrfs_truncate_inode_items as well.
>
> Signed-off-by: Nikolay Borisov <nborisov@xxxxxxxx>
Reviewed-by: Qu Wenruo <wqu@xxxxxxxx>
Thanks,
Qu
> ---
> V3:
> * Incorporate feedback from Qu and make btrfs_qgroup_trace_extent_post always
> return 0 since higher layers don't really handle errors properly.
>
> V2:
> * Always print a warning if btrfs_qgroup_trace_extent_post fails
> * Set quota inconsistent flag if btrfs_qgroup_trace_extent_post fails
> fs/btrfs/delayed-ref.c | 3 ++-
> fs/btrfs/qgroup.c | 7 +++++--
> 2 files changed, 7 insertions(+), 3 deletions(-)
>
> diff --git a/fs/btrfs/delayed-ref.c b/fs/btrfs/delayed-ref.c
> index a1a40cf382e3..7ab5e0128f0c 100644
> --- a/fs/btrfs/delayed-ref.c
> +++ b/fs/btrfs/delayed-ref.c
> @@ -821,7 +821,8 @@ int btrfs_add_delayed_tree_ref(struct btrfs_fs_info *fs_info,
> spin_unlock(&delayed_refs->lock);
>
> if (qrecord_inserted)
> - return btrfs_qgroup_trace_extent_post(fs_info, record);
> + btrfs_qgroup_trace_extent_post(fs_info, record);
> +
> return 0;
>
> free_head_ref:
> diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c
> index 9e61dd624f7b..ebde770ba498 100644
> --- a/fs/btrfs/qgroup.c
> +++ b/fs/btrfs/qgroup.c
> @@ -1442,8 +1442,11 @@ int btrfs_qgroup_trace_extent_post(struct btrfs_fs_info *fs_info,
> int ret;
>
> ret = btrfs_find_all_roots(NULL, fs_info, bytenr, 0, &old_root, false);
> - if (ret < 0)
> - return ret;
> + if (ret < 0) {
> + fs_info->qgroup_flags |= BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
> + btrfs_warn(fs_info, "Error accounting new delayed refs extent (err code: %d). Quota inconsistent", ret);
> + return 0;
> + }
>
> /*
> * Here we don't need to get the lock of
>
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