1 files changed, 109 insertions, 70 deletions

diff --git a/drivers/mtd/ubi/wl.c b/drivers/mtd/ubi/wl.c
index 891534f8210d..2b2472300610 100644
--- a/drivers/mtd/ubi/wl.c
+++ b/drivers/mtd/ubi/wl.c
@@ -55,8 +55,8 @@
  *
  * As it was said, for the UBI sub-system all physical eraseblocks are either
  * "free" or "used". Free eraseblock are kept in the @wl->free RB-tree, while
- * used eraseblocks are kept in @wl->used or @wl->scrub RB-trees, or
- * (temporarily) in the @wl->pq queue.
+ * used eraseblocks are kept in @wl->used, @wl->erroneous, or @wl->scrub
+ * RB-trees, as well as (temporarily) in the @wl->pq queue.
  *
  * When the WL sub-system returns a physical eraseblock, the physical
  * eraseblock is protected from being moved for some "time". For this reason,
@@ -83,6 +83,8 @@
  * used. The former state corresponds to the @wl->free tree. The latter state
  * is split up on several sub-states:
  * o the WL movement is allowed (@wl->used tree);
+ * o the WL movement is disallowed (@wl->erroneous) because the PEB is
+ *   erroneous - e.g., there was a read error;
  * o the WL movement is temporarily prohibited (@wl->pq queue);
  * o scrubbing is needed (@wl->scrub tree).
  *
@@ -653,7 +655,8 @@ static int schedule_erase(struct ubi_device *ubi, struct ubi_wl_entry *e,
 static int wear_leveling_worker(struct ubi_device *ubi, struct ubi_work *wrk,
                                 int cancel)
 {
-        int err, scrubbing = 0, torture = 0;
+        int err, scrubbing = 0, torture = 0, protect = 0, erroneous = 0;
+        int vol_id = -1, uninitialized_var(lnum);
         struct ubi_wl_entry *e1, *e2;
         struct ubi_vid_hdr *vid_hdr;
 
@@ -738,68 +741,78 @@ static int wear_leveling_worker(struct ubi_device *ubi, struct ubi_work *wrk,
                         /*
                          * We are trying to move PEB without a VID header. UBI
                          * always write VID headers shortly after the PEB was
-                         * given, so we have a situation when it did not have
-                         * chance to write it down because it was preempted.
-                         * Just re-schedule the work, so that next time it will
-                         * likely have the VID header in place.
+                         * given, so we have a situation when it has not yet
+                         * had a chance to write it, because it was preempted.
+                         * So add this PEB to the protection queue so far,
+                         * because presumably more data will be written there
+                         * (including the missing VID header), and then we'll
+                         * move it.
                          */
                         dbg_wl("PEB %d has no VID header", e1->pnum);
+                        protect = 1;
                         goto out_not_moved;
                 }
 
                 ubi_err("error %d while reading VID header from PEB %d",
                         err, e1->pnum);
-                if (err > 0)
-                        err = -EIO;
                 goto out_error;
         }
 
+        vol_id = be32_to_cpu(vid_hdr->vol_id);
+        lnum = be32_to_cpu(vid_hdr->lnum);
+
         err = ubi_eba_copy_leb(ubi, e1->pnum, e2->pnum, vid_hdr);
         if (err) {
-                if (err == -EAGAIN)
+                if (err == MOVE_CANCEL_RACE) {
+                        /*
+                         * The LEB has not been moved because the volume is
+                         * being deleted or the PEB has been put meanwhile. We
+                         * should prevent this PEB from being selected for
+                         * wear-leveling movement again, so put it to the
+                         * protection queue.
+                         */
+                        protect = 1;
                         goto out_not_moved;
-                if (err < 0)
-                        goto out_error;
-                if (err == 2) {
-                        /* Target PEB write error, torture it */
+                }
+
+                if (err == MOVE_CANCEL_BITFLIPS || err == MOVE_TARGET_WR_ERR ||
+                    err == MOVE_TARGET_RD_ERR) {
+                        /*
+                         * Target PEB had bit-flips or write error - torture it.
+                         */
                         torture = 1;
                         goto out_not_moved;
                 }
 
-                /*
-                 * The LEB has not been moved because the volume is being
-                 * deleted or the PEB has been put meanwhile. We should prevent
-                 * this PEB from being selected for wear-leveling movement
-                 * again, so put it to the protection queue.
-                 */
-
-                dbg_wl("canceled moving PEB %d", e1->pnum);
-                ubi_assert(err == 1);
-
-                ubi_free_vid_hdr(ubi, vid_hdr);
-                vid_hdr = NULL;
-
-                spin_lock(&ubi->wl_lock);
-                prot_queue_add(ubi, e1);
-                ubi_assert(!ubi->move_to_put);
-                ubi->move_from = ubi->move_to = NULL;
-                ubi->wl_scheduled = 0;
-                spin_unlock(&ubi->wl_lock);
+                if (err == MOVE_SOURCE_RD_ERR) {
+                        /*
+                         * An error happened while reading the source PEB. Do
+                         * not switch to R/O mode in this case, and give the
+                         * upper layers a possibility to recover from this,
+                         * e.g. by unmapping corresponding LEB. Instead, just
+                         * put this PEB to the @ubi->erroneous list to prevent
+                         * UBI from trying to move it over and over again.
+                         */
+                        if (ubi->erroneous_peb_count > ubi->max_erroneous) {
+                                ubi_err("too many erroneous eraseblocks (%d)",
+                                        ubi->erroneous_peb_count);
+                                goto out_error;
+                        }
+                        erroneous = 1;
+                        goto out_not_moved;
+                }
 
-                e1 = NULL;
-                err = schedule_erase(ubi, e2, 0);
-                if (err)
+                if (err < 0)
                         goto out_error;
-                mutex_unlock(&ubi->move_mutex);
-                return 0;
+
+                ubi_assert(0);
         }
 
         /* The PEB has been successfully moved */
-        ubi_free_vid_hdr(ubi, vid_hdr);
-        vid_hdr = NULL;
         if (scrubbing)
-                ubi_msg("scrubbed PEB %d, data moved to PEB %d",
-                        e1->pnum, e2->pnum);
+                ubi_msg("scrubbed PEB %d (LEB %d:%d), data moved to PEB %d",
+                        e1->pnum, vol_id, lnum, e2->pnum);
+        ubi_free_vid_hdr(ubi, vid_hdr);
 
         spin_lock(&ubi->wl_lock);
         if (!ubi->move_to_put) {
@@ -812,8 +825,10 @@ static int wear_leveling_worker(struct ubi_device *ubi, struct ubi_work *wrk,
 
         err = schedule_erase(ubi, e1, 0);
         if (err) {
-                e1 = NULL;
-                goto out_error;
+                kmem_cache_free(ubi_wl_entry_slab, e1);
+                if (e2)
+                        kmem_cache_free(ubi_wl_entry_slab, e2);
+                goto out_ro;
         }
 
         if (e2) {
@@ -821,10 +836,13 @@ static int wear_leveling_worker(struct ubi_device *ubi, struct ubi_work *wrk,
                  * Well, the target PEB was put meanwhile, schedule it for
                  * erasure.
                  */
-                dbg_wl("PEB %d was put meanwhile, erase", e2->pnum);
+                dbg_wl("PEB %d (LEB %d:%d) was put meanwhile, erase",
+                       e2->pnum, vol_id, lnum);
                 err = schedule_erase(ubi, e2, 0);
-                if (err)
-                        goto out_error;
+                if (err) {
+                        kmem_cache_free(ubi_wl_entry_slab, e2);
+                        goto out_ro;
+                }
         }
 
         dbg_wl("done");
@@ -837,11 +855,19 @@ static int wear_leveling_worker(struct ubi_device *ubi, struct ubi_work *wrk,
          * have been changed, schedule it for erasure.
          */
 out_not_moved:
-        dbg_wl("canceled moving PEB %d", e1->pnum);
-        ubi_free_vid_hdr(ubi, vid_hdr);
-        vid_hdr = NULL;
+        if (vol_id != -1)
+                dbg_wl("cancel moving PEB %d (LEB %d:%d) to PEB %d (%d)",
+                       e1->pnum, vol_id, lnum, e2->pnum, err);
+        else
+                dbg_wl("cancel moving PEB %d to PEB %d (%d)",
+                       e1->pnum, e2->pnum, err);
         spin_lock(&ubi->wl_lock);
-        if (scrubbing)
+        if (protect)
+                prot_queue_add(ubi, e1);
+        else if (erroneous) {
+                wl_tree_add(e1, &ubi->erroneous);
+                ubi->erroneous_peb_count += 1;
+        } else if (scrubbing)
                 wl_tree_add(e1, &ubi->scrub);
         else
                 wl_tree_add(e1, &ubi->used);
@@ -850,32 +876,36 @@ out_not_moved:
         ubi->wl_scheduled = 0;
         spin_unlock(&ubi->wl_lock);
 
-        e1 = NULL;
+        ubi_free_vid_hdr(ubi, vid_hdr);
         err = schedule_erase(ubi, e2, torture);
-        if (err)
-                goto out_error;
-
+        if (err) {
+                kmem_cache_free(ubi_wl_entry_slab, e2);
+                goto out_ro;
+        }
         mutex_unlock(&ubi->move_mutex);
         return 0;
 
 out_error:
-        ubi_err("error %d while moving PEB %d to PEB %d",
-                err, e1->pnum, e2->pnum);
-
-        ubi_free_vid_hdr(ubi, vid_hdr);
+        if (vol_id != -1)
+                ubi_err("error %d while moving PEB %d to PEB %d",
+                        err, e1->pnum, e2->pnum);
+        else
+                ubi_err("error %d while moving PEB %d (LEB %d:%d) to PEB %d",
+                        err, e1->pnum, vol_id, lnum, e2->pnum);
         spin_lock(&ubi->wl_lock);
         ubi->move_from = ubi->move_to = NULL;
         ubi->move_to_put = ubi->wl_scheduled = 0;
         spin_unlock(&ubi->wl_lock);
 
-        if (e1)
-                kmem_cache_free(ubi_wl_entry_slab, e1);
-        if (e2)
-                kmem_cache_free(ubi_wl_entry_slab, e2);
-        ubi_ro_mode(ubi);
+        ubi_free_vid_hdr(ubi, vid_hdr);
+        kmem_cache_free(ubi_wl_entry_slab, e1);
+        kmem_cache_free(ubi_wl_entry_slab, e2);
 
+out_ro:
+        ubi_ro_mode(ubi);
         mutex_unlock(&ubi->move_mutex);
-        return err;
+        ubi_assert(err != 0);
+        return err < 0 ? err : -EIO;
 
 out_cancel:
         ubi->wl_scheduled = 0;
@@ -1015,7 +1045,7 @@ static int erase_worker(struct ubi_device *ubi, struct ubi_work *wl_wrk,
                 /*
                  * If this is not %-EIO, we have no idea what to do. Scheduling
                  * this physical eraseblock for erasure again would cause
-                 * errors again and again. Well, lets switch to RO mode.
+                 * errors again and again. Well, lets switch to R/O mode.
                  */
                 goto out_ro;
         }
@@ -1043,10 +1073,9 @@ static int erase_worker(struct ubi_device *ubi, struct ubi_work *wl_wrk,
                 ubi_err("no reserved physical eraseblocks");
                 goto out_ro;
         }
-
         spin_unlock(&ubi->volumes_lock);
-        ubi_msg("mark PEB %d as bad", pnum);
 
+        ubi_msg("mark PEB %d as bad", pnum);
         err = ubi_io_mark_bad(ubi, pnum);
         if (err)
                 goto out_ro;
@@ -1056,7 +1085,9 @@ static int erase_worker(struct ubi_device *ubi, struct ubi_work *wl_wrk,
         ubi->bad_peb_count += 1;
         ubi->good_peb_count -= 1;
         ubi_calculate_reserved(ubi);
-        if (ubi->beb_rsvd_pebs == 0)
+        if (ubi->beb_rsvd_pebs)
+                ubi_msg("%d PEBs left in the reserve", ubi->beb_rsvd_pebs);
+        else
                 ubi_warn("last PEB from the reserved pool was used");
         spin_unlock(&ubi->volumes_lock);
 
@@ -1125,6 +1156,13 @@ retry:
                 } else if (in_wl_tree(e, &ubi->scrub)) {
                         paranoid_check_in_wl_tree(e, &ubi->scrub);
                         rb_erase(&e->u.rb, &ubi->scrub);
+                } else if (in_wl_tree(e, &ubi->erroneous)) {
+                        paranoid_check_in_wl_tree(e, &ubi->erroneous);
+                        rb_erase(&e->u.rb, &ubi->erroneous);
+                        ubi->erroneous_peb_count -= 1;
+                        ubi_assert(ubi->erroneous_peb_count >= 0);
+                        /* Erroneous PEBs should be tortured */
+                        torture = 1;
                 } else {
                         err = prot_queue_del(ubi, e->pnum);
                         if (err) {
@@ -1373,7 +1411,7 @@ int ubi_wl_init_scan(struct ubi_device *ubi, struct ubi_scan_info *si)
         struct ubi_scan_leb *seb, *tmp;
         struct ubi_wl_entry *e;
 
-        ubi->used = ubi->free = ubi->scrub = RB_ROOT;
+        ubi->used = ubi->erroneous = ubi->free = ubi->scrub = RB_ROOT;
         spin_lock_init(&ubi->wl_lock);
         mutex_init(&ubi->move_mutex);
         init_rwsem(&ubi->work_sem);
@@ -1511,6 +1549,7 @@ void ubi_wl_close(struct ubi_device *ubi)
         cancel_pending(ubi);
         protection_queue_destroy(ubi);
         tree_destroy(&ubi->used);
+        tree_destroy(&ubi->erroneous);
         tree_destroy(&ubi->free);
         tree_destroy(&ubi->scrub);
         kfree(ubi->lookuptbl);