diff options
| -rw-r--r-- | drivers/mtd/ubi/scan.c | 76 |
1 files changed, 74 insertions, 2 deletions
diff --git a/drivers/mtd/ubi/scan.c b/drivers/mtd/ubi/scan.c index 19dc5e0..def0bf0 100644 --- a/drivers/mtd/ubi/scan.c +++ b/drivers/mtd/ubi/scan.c @@ -123,8 +123,8 @@ static int add_to_list(struct ubi_scan_info *si, int pnum, int ec, int to_head, * @ec: erase counter of the physical eraseblock * * This function adds corrupted physical eraseblock @pnum to the 'corr' list. - * Returns zero in case of success and a negative error code in case of - * failure. + * The corruption was presumably not caused by a power cut. Returns zero in + * case of success and a negative error code in case of failure. */ static int add_corrupted(struct ubi_scan_info *si, int pnum, int ec) { @@ -751,6 +751,53 @@ struct ubi_scan_leb *ubi_scan_get_free_peb(struct ubi_device *ubi, } /** + * check_data_ff - make sure PEB contains only 0xFF data. + * @ubi: UBI device description object + * @vid_hrd: the (corrupted) VID header of this PEB + * @pnum: the physical eraseblock number to check + * + * This is a helper function which is used to distinguish between VID header + * corruptions caused by power cuts and other reasons. If the PEB contains only + * 0xFF bytes at the data area, the VID header is most probably corrupted + * because of a power cut (%0 is returned in this case). Otherwise, it was + * corrupted for some other reasons (%1 is returned in this case). A negative + * error code is returned if a read error occurred. + * + * If the corruption reason was a power cut, UBI can safely erase this PEB. + * Otherwise, it should preserve it to avoid possibly destroying important + * information. + */ +static int check_data_ff(struct ubi_device *ubi, struct ubi_vid_hdr *vid_hdr, + int pnum) +{ + int err; + + mutex_lock(&ubi->buf_mutex); + memset(ubi->peb_buf1, 0x00, ubi->leb_size); + + err = ubi_io_read(ubi, ubi->peb_buf1, pnum, ubi->leb_start, + ubi->leb_size); + if (err && err != UBI_IO_BITFLIPS && err != -EBADMSG) + return err; + + if (ubi_check_pattern(ubi->peb_buf1, 0xFF, ubi->leb_size)) { + mutex_unlock(&ubi->buf_mutex); + return 0; + } + + ubi_err("PEB %d contains corrupted VID header, and the data does not " + "contain all 0xFF, this may be a non-UBI PEB or a severe VID " + "header corruption which requires manual inspection", pnum); + ubi_dbg_dump_vid_hdr(vid_hdr); + dbg_msg("hexdump of PEB %d offset %d, length %d", + pnum, ubi->leb_start, ubi->leb_size); + ubi_dbg_print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_OFFSET, 32, 1, + ubi->peb_buf1, ubi->leb_size, 1); + mutex_unlock(&ubi->buf_mutex); + return -EINVAL; +} + +/** * process_eb - read, check UBI headers, and add them to scanning information. * @ubi: UBI device description object * @si: scanning information @@ -883,6 +930,31 @@ static int process_eb(struct ubi_device *ubi, struct ubi_scan_info *si, */ si->maybe_bad_peb_count += 1; case UBI_IO_BAD_HDR: + if (ec_err) + /* + * Both headers are corrupted. There is a possibility + * that this a valid UBI PEB which has corresponding + * LEB, but the headers are corrupted. However, it is + * impossible to distinguish it from a PEB which just + * contains garbage because a power cut during erase + * operation. So we just schedule this PEB for erasure. + */ + err = 0; + else + /* + * The EC was OK, but the VID header is corrupted. We + * have to check what is in the data area. + */ + err = check_data_ff(ubi, vidh, pnum); + if (!err) + /* This corruption is caused by a power cut */ + err = add_to_list(si, pnum, ec, 1, &si->erase); + else + /* This is an unexpected corruption */ + err = add_corrupted(si, pnum, ec); + if (err) + return err; + goto adjust_mean_ec; case UBI_IO_FF_BITFLIPS: err = add_to_list(si, pnum, ec, 1, &si->erase); if (err) |
