Am 21.06.2016 um 00:25 schrieb Richard Weinberger:
> recover_peb() was never power cut aware,
> if a power cut happened right after writing the VID header
> upon next attach UBI would blindly use the new partial written
> PEB and all data from the old PEB is lost.
>
> In order to make recover_peb() power cut aware, write the new
> VID with a proper crc and copy_flag set such that the UBI attach
> process will detect whether the new PEB is completely written
> or not.
> We cannot directly use ubi_eba_atomic_leb_change() since we'd
> have to unlock the LEB which is facing a write error.
>
> Cc: stable@xxxxxxxxxxxxxxx
> Reported-by: Jörg Pfähler <pfaehler@xxxxxxx>
> Signed-off-by: Richard Weinberger <richard@xxxxxx>
> ---
> drivers/mtd/ubi/eba.c | 21 ++++++++++++++-------
> 1 file changed, 14 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/mtd/ubi/eba.c b/drivers/mtd/ubi/eba.c
> index 5780dd1..b6b0714 100644
> --- a/drivers/mtd/ubi/eba.c
> +++ b/drivers/mtd/ubi/eba.c
> @@ -575,6 +575,7 @@ static int recover_peb(struct ubi_device *ubi, int pnum, int vol_id, int lnum,
> int err, idx = vol_id2idx(ubi, vol_id), new_pnum, data_size, tries = 0;
> struct ubi_volume *vol = ubi->volumes[idx];
> struct ubi_vid_hdr *vid_hdr;
> + uint32_t crc;
>
> vid_hdr = ubi_zalloc_vid_hdr(ubi, GFP_NOFS);
> if (!vid_hdr)
> @@ -599,14 +600,8 @@ retry:
> goto out_put;
> }
>
> - vid_hdr->sqnum = cpu_to_be64(ubi_next_sqnum(ubi));
> - err = ubi_io_write_vid_hdr(ubi, new_pnum, vid_hdr);
> - if (err) {
> - up_read(&ubi->fm_eba_sem);
> - goto write_error;
> - }
> + ubi_assert(vid_hdr->vol_type == UBI_VID_DYNAMIC);
>
> - data_size = offset + len;
> mutex_lock(&ubi->buf_mutex);
> memset(ubi->peb_buf + offset, 0xFF, len);
>
> @@ -621,6 +616,18 @@ retry:
>
> memcpy(ubi->peb_buf + offset, buf, len);
>
> + data_size = offset + len;
> + crc = crc32(UBI_CRC32_INIT, ubi->peb_buf, data_size);
> + vid_hdr->sqnum = cpu_to_be64(ubi_next_sqnum(ubi));
> + vid_hdr->copy_flag = 1;
> + vid_hdr->data_size = cpu_to_be32(data_size);
> + vid_hdr->data_crc = cpu_to_be32(crc);
> + err = ubi_io_write_vid_hdr(ubi, new_pnum, vid_hdr);
> + if (err) {
> + up_read(&ubi->fm_eba_sem);
> + goto out_unlock;
As always, right after sending a patch I spot an issue... ;-\
We need to goto write_error here (and release buf_mutex first).
Thanks,
//richard
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