From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from out1-smtp.messagingengine.com ([66.111.4.25]:39741 "EHLO out1-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752062AbeGANZa (ORCPT ); Sun, 1 Jul 2018 09:25:30 -0400 Subject: FAILED: patch "[PATCH] ubi: fastmap: Correctly handle interrupted erasures in EBA" failed to apply to 3.18-stable tree To: richard@nod.at, Martinbayern@outlook.com, stable@vger.kernel.org Cc: From: Date: Sun, 01 Jul 2018 15:25:28 +0200 Message-ID: <153045152812710@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: The patch below does not apply to the 3.18-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >>From 781932375ffc6411713ee0926ccae8596ed0261c Mon Sep 17 00:00:00 2001 From: Richard Weinberger Date: Mon, 28 May 2018 22:04:32 +0200 Subject: [PATCH] ubi: fastmap: Correctly handle interrupted erasures in EBA Fastmap cannot track the LEB unmap operation, therefore it can happen that after an interrupted erasure the mapping still looks good from Fastmap's point of view, while reading from the PEB will cause an ECC error and confuses the upper layer. Instead of teaching users of UBI how to deal with that, we read back the VID header and check for errors. If the PEB is empty or shows ECC errors we fixup the mapping and schedule the PEB for erasure. Fixes: dbb7d2a88d2a ("UBI: Add fastmap core") Cc: Reported-by: martin bayern Signed-off-by: Richard Weinberger diff --git a/drivers/mtd/ubi/eba.c b/drivers/mtd/ubi/eba.c index 250e30fac61b..593a4f9d97e3 100644 --- a/drivers/mtd/ubi/eba.c +++ b/drivers/mtd/ubi/eba.c @@ -490,6 +490,82 @@ int ubi_eba_unmap_leb(struct ubi_device *ubi, struct ubi_volume *vol, return err; } +#ifdef CONFIG_MTD_UBI_FASTMAP +/** + * check_mapping - check and fixup a mapping + * @ubi: UBI device description object + * @vol: volume description object + * @lnum: logical eraseblock number + * @pnum: physical eraseblock number + * + * Checks whether a given mapping is valid. Fastmap cannot track LEB unmap + * operations, if such an operation is interrupted the mapping still looks + * good, but upon first read an ECC is reported to the upper layer. + * Normaly during the full-scan at attach time this is fixed, for Fastmap + * we have to deal with it while reading. + * If the PEB behind a LEB shows this symthom we change the mapping to + * %UBI_LEB_UNMAPPED and schedule the PEB for erasure. + * + * Returns 0 on success, negative error code in case of failure. + */ +static int check_mapping(struct ubi_device *ubi, struct ubi_volume *vol, int lnum, + int *pnum) +{ + int err; + struct ubi_vid_io_buf *vidb; + + if (!ubi->fast_attach) + return 0; + + vidb = ubi_alloc_vid_buf(ubi, GFP_NOFS); + if (!vidb) + return -ENOMEM; + + err = ubi_io_read_vid_hdr(ubi, *pnum, vidb, 0); + if (err > 0 && err != UBI_IO_BITFLIPS) { + int torture = 0; + + switch (err) { + case UBI_IO_FF: + case UBI_IO_FF_BITFLIPS: + case UBI_IO_BAD_HDR: + case UBI_IO_BAD_HDR_EBADMSG: + break; + default: + ubi_assert(0); + } + + if (err == UBI_IO_BAD_HDR_EBADMSG || err == UBI_IO_FF_BITFLIPS) + torture = 1; + + down_read(&ubi->fm_eba_sem); + vol->eba_tbl->entries[lnum].pnum = UBI_LEB_UNMAPPED; + up_read(&ubi->fm_eba_sem); + ubi_wl_put_peb(ubi, vol->vol_id, lnum, *pnum, torture); + + *pnum = UBI_LEB_UNMAPPED; + } else if (err < 0) { + ubi_err(ubi, "unable to read VID header back from PEB %i: %i", + *pnum, err); + + goto out_free; + } + + err = 0; + +out_free: + ubi_free_vid_buf(vidb); + + return err; +} +#else +static int check_mapping(struct ubi_device *ubi, struct ubi_volume *vol, int lnum, + int *pnum) +{ + return 0; +} +#endif + /** * ubi_eba_read_leb - read data. * @ubi: UBI device description object @@ -522,7 +598,13 @@ int ubi_eba_read_leb(struct ubi_device *ubi, struct ubi_volume *vol, int lnum, return err; pnum = vol->eba_tbl->entries[lnum].pnum; - if (pnum < 0) { + if (pnum >= 0) { + err = check_mapping(ubi, vol, lnum, &pnum); + if (err < 0) + goto out_unlock; + } + + if (pnum == UBI_LEB_UNMAPPED) { /* * The logical eraseblock is not mapped, fill the whole buffer * with 0xFF bytes. The exception is static volumes for which @@ -930,6 +1012,12 @@ int ubi_eba_write_leb(struct ubi_device *ubi, struct ubi_volume *vol, int lnum, return err; pnum = vol->eba_tbl->entries[lnum].pnum; + if (pnum >= 0) { + err = check_mapping(ubi, vol, lnum, &pnum); + if (err < 0) + goto out; + } + if (pnum >= 0) { dbg_eba("write %d bytes at offset %d of LEB %d:%d, PEB %d", len, offset, vol_id, lnum, pnum);