On 2018/10/23 下午5:41, Su Yue wrote:
> Previously, @err are assigned immediately after check but before
> repair.
> repair_extent_item()'s return value also confuses the caller. If
> error has been repaired and returns 0, check_extent_item() will try
> to continue check the nonexistent and cause flase alerts.
>
> Here make repair_extent_item()'s return codes only represents status
> of the extent item, error bits are passed by pointer.
> Move the change of @err after repair.
>
> Signed-off-by: Su Yue <suy.fnst@xxxxxxxxxxxxxx>
> ---
> check/mode-lowmem.c | 106 ++++++++++++++++++++++++++++----------------
> 1 file changed, 68 insertions(+), 38 deletions(-)
>
> diff --git a/check/mode-lowmem.c b/check/mode-lowmem.c
> index 76e7be81ceb1..769b3141de8b 100644
> --- a/check/mode-lowmem.c
> +++ b/check/mode-lowmem.c
> @@ -3788,35 +3788,35 @@ out:
> /*
> * Only delete backref if REFERENCER_MISSING now
> *
> - * Returns <0 the extent was deleted
> - * Returns >0 the backref was deleted but extent still exists, returned value
> - * means error after repair
> + * Returns <0 the whole extent item was deleted
> + * Returns >0 the backref was deleted but extent still exists, @err_ret
> + * will be set to be error bits after repair.
Well, I have to admit the parameter list is really human friendly from
the initial design.
In fact, the only real user of @err is just that "if ((err &
(REFERENCER_MISSING | REFERENCER_MISMATCH)) == 0)" line.
We can in fact get rid of that @err parameter and do that check at the
only caller of repair_extent_item().
And then redefine the return value.
Like "Return < 0 if we failed to repair backref for the extent.
Return 0 if we repaired the backref for the extent".
[snip]
>
> - if (err && repair) {
> + if (tmp_err && repair) {
> ret = repair_extent_item(fs_info->extent_root, path,
> key.objectid, num_bytes, parent, root_objectid,
> - owner, owner_offset, ret);
> - if (ret < 0)
If follow my above method, here the code can be a little easier:
if (tmp_err && repair) {
if (!(tmp_err & (REFERENCER_MISSING |
REFENCER_MISMATCH)) {
err |= tmp_err;
goto next;
}
ret = repair_extent_item(...);
if (ret < 0)
err |= tmp_err;
} else if (tmp_err) {
err |= tmp_err;
}
Without the need to passing @err into repair_extent_item() nor modifying
@err in that function.
Thanks,
Qu
> + owner, owner_offset, &tmp_err);
> + err |= tmp_err;
> +
> + if (tmp_err & FATAL_ERROR || ret < 0)
> goto out;
> - if (ret) {
> + /*
> + * the error has been repaired which means the extent item
> + * is still existed with other backrefs, go to check next.
> + */> + if (ret > 0) {
> + eb = path->nodes[0];
> + slot = path->slots[0];
> + ei = btrfs_item_ptr(eb, slot, struct btrfs_extent_item);
> + item_size = btrfs_item_size_nr(eb, slot);
> goto next;
> - err = ret;
> }
> + } else {
> + err |= tmp_err;
> }
>
> - ptr += btrfs_extent_inline_ref_size(type);
> + ptr_offset += btrfs_extent_inline_ref_size(type);
> goto next;
>
> out:
>
