[PATCH] mtd: ubi: eba.c: fix return value overwrite issue in try_write_vid_and_data()
Zhihao Cheng
chengzhihao1 at huawei.com
Sun Mar 19 19:44:51 PDT 2023
Good catch. Maybe many of history happened unconsistent ubifs images
have related to this point. One small nit below.
> The commit 2d78aee426d8 ("UBI: simplify LEB write and atomic LEB change code")
> adds helper function, try_write_vid_and_data(), to simplify the code, but this
> helper function has bug, it will return 0 (success) when ubi_io_write_vid_hdr()
> or the ubi_io_write_data() return error number (-EIO, etc), because the return
> value of ubi_wl_put_peb() will overwrite the original return value.
>
> This issue will cause unexpected data loss issue, because the caller of this
> function and UBIFS willn't know the data is lost.
>
> Fixes: 2d78aee426d8 ("UBI: simplify LEB write and atomic LEB change code")
>
> Signed-off-by: Wang YanQing <udknight at gmail.com>
> ---
> drivers/mtd/ubi/eba.c | 15 +++++++++++----
> 1 file changed, 11 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/mtd/ubi/eba.c b/drivers/mtd/ubi/eba.c
> index 09c408c..4e32b25 100644
> --- a/drivers/mtd/ubi/eba.c
> +++ b/drivers/mtd/ubi/eba.c
> @@ -981,10 +981,17 @@ static int try_write_vid_and_data(struct ubi_volume *vol, int lnum,
> out_put:
> up_read(&ubi->fm_eba_sem);
>
> - if (err && pnum >= 0)
> - err = ubi_wl_put_peb(ubi, vol_id, lnum, pnum, 1);
> - else if (!err && opnum >= 0)
> - err = ubi_wl_put_peb(ubi, vol_id, lnum, opnum, 0);
> + if (err && pnum >= 0) {
> + if (ubi_wl_put_peb(ubi, vol_id, lnum, pnum, 1) != 0) {
Could we also add error code returned from ubi_wl_put_peb() in warning
message? Same with next ubifs_warn.
> + ubi_warn(ubi, "failed to return physical eraseblock %d",
> + pnum);
> + }
> + } else if (!err && opnum >= 0) {
> + if (ubi_wl_put_peb(ubi, vol_id, lnum, opnum, 0) != 0) {
> + ubi_warn(ubi, "failed to return physical eraseblock %d",
> + opnum);
> + }
> + }
>
> return err;
> }
>
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