1 files changed, 47 insertions, 89 deletions

diff --git a/drivers/mtd/ubi/scan.c b/drivers/mtd/ubi/scan.c
index 96d410e106ab..967bb4406df9 100644
--- a/drivers/mtd/ubi/scan.c
+++ b/drivers/mtd/ubi/scan.c
@@ -19,9 +19,9 @@
  */
 
 /*
- * UBI scanning unit.
+ * UBI scanning sub-system.
  *
- * This unit is responsible for scanning the flash media, checking UBI
+ * This sub-system is responsible for scanning the flash media, checking UBI
  * headers and providing complete information about the UBI flash image.
  *
  * The scanning information is represented by a &struct ubi_scan_info' object.
@@ -93,8 +93,7 @@ static int add_to_list(struct ubi_scan_info *si, int pnum, int ec,
 }
 
 /**
- * validate_vid_hdr - check that volume identifier header is correct and
- * consistent.
+ * validate_vid_hdr - check volume identifier header.
  * @vid_hdr: the volume identifier header to check
  * @sv: information about the volume this logical eraseblock belongs to
  * @pnum: physical eraseblock number the VID header came from
@@ -103,7 +102,7 @@ static int add_to_list(struct ubi_scan_info *si, int pnum, int ec,
  * non-zero if an inconsistency was found and zero if not.
  *
  * Note, UBI does sanity check of everything it reads from the flash media.
- * Most of the checks are done in the I/O unit. Here we check that the
+ * Most of the checks are done in the I/O sub-system. Here we check that the
  * information in the VID header is consistent to the information in other VID
  * headers of the same volume.
  */
@@ -247,45 +246,21 @@ static int compare_lebs(struct ubi_device *ubi, const struct ubi_scan_leb *seb,
         struct ubi_vid_hdr *vh = NULL;
         unsigned long long sqnum2 = be64_to_cpu(vid_hdr->sqnum);
 
-        if (seb->sqnum == 0 && sqnum2 == 0) {
-                long long abs, v1 = seb->leb_ver, v2 = be32_to_cpu(vid_hdr->leb_ver);
-
+        if (sqnum2 == seb->sqnum) {
                 /*
-                 * UBI constantly increases the logical eraseblock version
-                 * number and it can overflow. Thus, we have to bear in mind
-                 * that versions that are close to %0xFFFFFFFF are less then
-                 * versions that are close to %0.
-                 *
-                 * The UBI WL unit guarantees that the number of pending tasks
-                 * is not greater then %0x7FFFFFFF. So, if the difference
-                 * between any two versions is greater or equivalent to
-                 * %0x7FFFFFFF, there was an overflow and the logical
-                 * eraseblock with lower version is actually newer then the one
-                 * with higher version.
-                 *
-                 * FIXME: but this is anyway obsolete and will be removed at
-                 * some point.
+                 * This must be a really ancient UBI image which has been
+                 * created before sequence numbers support has been added. At
+                 * that times we used 32-bit LEB versions stored in logical
+                 * eraseblocks. That was before UBI got into mainline. We do not
+                 * support these images anymore. Well, those images will work
+                 * still work, but only if no unclean reboots happened.
                  */
-                dbg_bld("using old crappy leb_ver stuff");
-
-                if (v1 == v2) {
-                        ubi_err("PEB %d and PEB %d have the same version %lld",
-                                seb->pnum, pnum, v1);
-                        return -EINVAL;
-                }
-
-                abs = v1 - v2;
-                if (abs < 0)
-                        abs = -abs;
+                ubi_err("unsupported on-flash UBI format\n");
+                return -EINVAL;
+        }
 
-                if (abs < 0x7FFFFFFF)
-                        /* Non-overflow situation */
-                        second_is_newer = (v2 > v1);
-                else
-                        second_is_newer = (v2 < v1);
-        } else
-                /* Obviously the LEB with lower sequence counter is older */
-                second_is_newer = sqnum2 > seb->sqnum;
+        /* Obviously the LEB with lower sequence counter is older */
+        second_is_newer = !!(sqnum2 > seb->sqnum);
 
         /*
          * Now we know which copy is newer. If the copy flag of the PEB with
@@ -293,7 +268,7 @@ static int compare_lebs(struct ubi_device *ubi, const struct ubi_scan_leb *seb,
          * check data CRC. For the second PEB we already have the VID header,
          * for the first one - we'll need to re-read it from flash.
          *
-         * FIXME: this may be optimized so that we wouldn't read twice.
+         * Note: this may be optimized so that we wouldn't read twice.
          */
 
         if (second_is_newer) {
@@ -379,8 +354,7 @@ out_free_vidh:
 }
 
 /**
- * ubi_scan_add_used - add information about a physical eraseblock to the
- * scanning information.
+ * ubi_scan_add_used - add physical eraseblock to the scanning information.
  * @ubi: UBI device description object
  * @si: scanning information
  * @pnum: the physical eraseblock number
@@ -400,7 +374,6 @@ int ubi_scan_add_used(struct ubi_device *ubi, struct ubi_scan_info *si,
                       int bitflips)
 {
         int err, vol_id, lnum;
-        uint32_t leb_ver;
         unsigned long long sqnum;
         struct ubi_scan_volume *sv;
         struct ubi_scan_leb *seb;
@@ -409,10 +382,9 @@ int ubi_scan_add_used(struct ubi_device *ubi, struct ubi_scan_info *si,
         vol_id = be32_to_cpu(vid_hdr->vol_id);
         lnum = be32_to_cpu(vid_hdr->lnum);
         sqnum = be64_to_cpu(vid_hdr->sqnum);
-        leb_ver = be32_to_cpu(vid_hdr->leb_ver);
 
-        dbg_bld("PEB %d, LEB %d:%d, EC %d, sqnum %llu, ver %u, bitflips %d",
-                pnum, vol_id, lnum, ec, sqnum, leb_ver, bitflips);
+        dbg_bld("PEB %d, LEB %d:%d, EC %d, sqnum %llu, bitflips %d",
+                pnum, vol_id, lnum, ec, sqnum, bitflips);
 
         sv = add_volume(si, vol_id, pnum, vid_hdr);
         if (IS_ERR(sv) < 0)
@@ -445,25 +417,20 @@ int ubi_scan_add_used(struct ubi_device *ubi, struct ubi_scan_info *si,
                  */
 
                 dbg_bld("this LEB already exists: PEB %d, sqnum %llu, "
-                        "LEB ver %u, EC %d", seb->pnum, seb->sqnum,
-                        seb->leb_ver, seb->ec);
-
-                /*
-                 * Make sure that the logical eraseblocks have different
-                 * versions. Otherwise the image is bad.
-                 */
-                if (seb->leb_ver == leb_ver && leb_ver != 0) {
-                        ubi_err("two LEBs with same version %u", leb_ver);
-                        ubi_dbg_dump_seb(seb, 0);
-                        ubi_dbg_dump_vid_hdr(vid_hdr);
-                        return -EINVAL;
-                }
+                        "EC %d", seb->pnum, seb->sqnum, seb->ec);
 
                 /*
                  * Make sure that the logical eraseblocks have different
                  * sequence numbers. Otherwise the image is bad.
                  *
-                 * FIXME: remove 'sqnum != 0' check when leb_ver is removed.
+                 * However, if the sequence number is zero, we assume it must
+                 * be an ancient UBI image from the era when UBI did not have
+                 * sequence numbers. We still can attach these images, unless
+                 * there is a need to distinguish between old and new
+                 * eraseblocks, in which case we'll refuse the image in
+                 * 'compare_lebs()'. In other words, we attach old clean
+                 * images, but refuse attaching old images with duplicated
+                 * logical eraseblocks because there was an unclean reboot.
                  */
                 if (seb->sqnum == sqnum && sqnum != 0) {
                         ubi_err("two LEBs with same sequence number %llu",
@@ -503,7 +470,6 @@ int ubi_scan_add_used(struct ubi_device *ubi, struct ubi_scan_info *si,
                         seb->pnum = pnum;
                         seb->scrub = ((cmp_res & 2) || bitflips);
                         seb->sqnum = sqnum;
-                        seb->leb_ver = leb_ver;
 
                         if (sv->highest_lnum == lnum)
                                 sv->last_data_size =
@@ -540,7 +506,6 @@ int ubi_scan_add_used(struct ubi_device *ubi, struct ubi_scan_info *si,
         seb->lnum = lnum;
         seb->sqnum = sqnum;
         seb->scrub = bitflips;
-        seb->leb_ver = leb_ver;
 
         if (sv->highest_lnum <= lnum) {
                 sv->highest_lnum = lnum;
@@ -554,8 +519,7 @@ int ubi_scan_add_used(struct ubi_device *ubi, struct ubi_scan_info *si,
 }
 
 /**
- * ubi_scan_find_sv - find information about a particular volume in the
- * scanning information.
+ * ubi_scan_find_sv - find volume in the scanning information.
  * @si: scanning information
  * @vol_id: the requested volume ID
  *
@@ -584,8 +548,7 @@ struct ubi_scan_volume *ubi_scan_find_sv(const struct ubi_scan_info *si,
 }
 
 /**
- * ubi_scan_find_seb - find information about a particular logical
- * eraseblock in the volume scanning information.
+ * ubi_scan_find_seb - find LEB in the volume scanning information.
  * @sv: a pointer to the volume scanning information
  * @lnum: the requested logical eraseblock
  *
@@ -645,9 +608,9 @@ void ubi_scan_rm_volume(struct ubi_scan_info *si, struct ubi_scan_volume *sv)
  *
  * This function erases physical eraseblock 'pnum', and writes the erase
  * counter header to it. This function should only be used on UBI device
- * initialization stages, when the EBA unit had not been yet initialized. This
- * function returns zero in case of success and a negative error code in case
- * of failure.
+ * initialization stages, when the EBA sub-system had not been yet initialized.
+ * This function returns zero in case of success and a negative error code in
+ * case of failure.
  */
 int ubi_scan_erase_peb(struct ubi_device *ubi, const struct ubi_scan_info *si,
                        int pnum, int ec)
@@ -687,9 +650,10 @@ out_free:
  * @si: scanning information
  *
  * This function returns a free physical eraseblock. It is supposed to be
- * called on the UBI initialization stages when the wear-leveling unit is not
- * initialized yet. This function picks a physical eraseblocks from one of the
- * lists, writes the EC header if it is needed, and removes it from the list.
+ * called on the UBI initialization stages when the wear-leveling sub-system is
+ * not initialized yet. This function picks a physical eraseblocks from one of
+ * the lists, writes the EC header if it is needed, and removes it from the
+ * list.
  *
  * This function returns scanning physical eraseblock information in case of
  * success and an error code in case of failure.
@@ -742,8 +706,7 @@ struct ubi_scan_leb *ubi_scan_get_free_peb(struct ubi_device *ubi,
 }
 
 /**
- * process_eb - read UBI headers, check them and add corresponding data
- * to the scanning information.
+ * process_eb - read, check UBI headers, and add them to scanning information.
  * @ubi: UBI device description object
  * @si: scanning information
  * @pnum: the physical eraseblock number
@@ -751,7 +714,8 @@ struct ubi_scan_leb *ubi_scan_get_free_peb(struct ubi_device *ubi,
  * This function returns a zero if the physical eraseblock was successfully
  * handled and a negative error code in case of failure.
  */
-static int process_eb(struct ubi_device *ubi, struct ubi_scan_info *si, int pnum)
+static int process_eb(struct ubi_device *ubi, struct ubi_scan_info *si,
+                      int pnum)
 {
         long long uninitialized_var(ec);
         int err, bitflips = 0, vol_id, ec_corr = 0;
@@ -764,8 +728,9 @@ static int process_eb(struct ubi_device *ubi, struct ubi_scan_info *si, int pnum
                 return err;
         else if (err) {
                 /*
-                 * FIXME: this is actually duty of the I/O unit to initialize
-                 * this, but MTD does not provide enough information.
+                 * FIXME: this is actually duty of the I/O sub-system to
+                 * initialize this, but MTD does not provide enough
+                 * information.
                  */
                 si->bad_peb_count += 1;
                 return 0;
@@ -930,7 +895,7 @@ struct ubi_scan_info *ubi_scan(struct ubi_device *ubi)
         for (pnum = 0; pnum < ubi->peb_count; pnum++) {
                 cond_resched();
 
-                dbg_msg("process PEB %d", pnum);
+                dbg_gen("process PEB %d", pnum);
                 err = process_eb(ubi, si, pnum);
                 if (err < 0)
                         goto out_vidh;
@@ -1079,8 +1044,7 @@ void ubi_scan_destroy_si(struct ubi_scan_info *si)
 #ifdef CONFIG_MTD_UBI_DEBUG_PARANOID
 
 /**
- * paranoid_check_si - check if the scanning information is correct and
- * consistent.
+ * paranoid_check_si - check the scanning information.
  * @ubi: UBI device description object
  * @si: scanning information
  *
@@ -1265,11 +1229,6 @@ static int paranoid_check_si(struct ubi_device *ubi, struct ubi_scan_info *si)
                                 ubi_err("bad data_pad %d", sv->data_pad);
                                 goto bad_vid_hdr;
                         }
-
-                        if (seb->leb_ver != be32_to_cpu(vidh->leb_ver)) {
-                                ubi_err("bad leb_ver %u", seb->leb_ver);
-                                goto bad_vid_hdr;
-                        }
                 }
 
                 if (!last_seb)
@@ -1299,8 +1258,7 @@ static int paranoid_check_si(struct ubi_device *ubi, struct ubi_scan_info *si)
                 if (err < 0) {
                         kfree(buf);
                         return err;
-                }
-                else if (err)
+                } else if (err)
                         buf[pnum] = 1;
         }