]> git.kernelconcepts.de Git - karo-tx-uboot.git/blobdiff - drivers/mtd/ubi/wl.c
Merge branch 'master' of git://git.denx.de/u-boot-arc
[karo-tx-uboot.git] / drivers / mtd / ubi / wl.c
index 2f9a5e3653e024012ea21a892afa494e5a7f4a86..102309016ac43d7a83de295218c4987b19da6c40 100644 (file)
 /*
  * Copyright (c) International Business Machines Corp., 2006
  *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
- * the GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ * SPDX-License-Identifier:    GPL-2.0+
  *
  * Authors: Artem Bityutskiy (Битюцкий Артём), Thomas Gleixner
  */
 
 /*
- * UBI wear-leveling unit.
+ * UBI wear-leveling sub-system.
  *
- * This unit is responsible for wear-leveling. It works in terms of physical
- * eraseblocks and erase counters and knows nothing about logical eraseblocks,
- * volumes, etc. From this unit's perspective all physical eraseblocks are of
- * two types - used and free. Used physical eraseblocks are those that were
- * "get" by the 'ubi_wl_get_peb()' function, and free physical eraseblocks are
- * those that were put by the 'ubi_wl_put_peb()' function.
+ * This sub-system is responsible for wear-leveling. It works in terms of
+ * physical eraseblocks and erase counters and knows nothing about logical
+ * eraseblocks, volumes, etc. From this sub-system's perspective all physical
+ * eraseblocks are of two types - used and free. Used physical eraseblocks are
+ * those that were "get" by the 'ubi_wl_get_peb()' function, and free physical
+ * eraseblocks are those that were put by the 'ubi_wl_put_peb()' function.
  *
  * Physical eraseblocks returned by 'ubi_wl_get_peb()' have only erase counter
- * header. The rest of the physical eraseblock contains only 0xFF bytes.
+ * header. The rest of the physical eraseblock contains only %0xFF bytes.
  *
- * When physical eraseblocks are returned to the WL unit by means of the
+ * When physical eraseblocks are returned to the WL sub-system by means of the
  * 'ubi_wl_put_peb()' function, they are scheduled for erasure. The erasure is
  * done asynchronously in context of the per-UBI device background thread,
- * which is also managed by the WL unit.
+ * which is also managed by the WL sub-system.
  *
  * The wear-leveling is ensured by means of moving the contents of used
  * physical eraseblocks with low erase counter to free physical eraseblocks
  * with high erase counter.
  *
- * The 'ubi_wl_get_peb()' function accepts data type hints which help to pick
- * an "optimal" physical eraseblock. For example, when it is known that the
- * physical eraseblock will be "put" soon because it contains short-term data,
- * the WL unit may pick a free physical eraseblock with low erase counter, and
- * so forth.
+ * If the WL sub-system fails to erase a physical eraseblock, it marks it as
+ * bad.
+ *
+ * This sub-system is also responsible for scrubbing. If a bit-flip is detected
+ * in a physical eraseblock, it has to be moved. Technically this is the same
+ * as moving it for wear-leveling reasons.
+ *
+ * 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, @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,
+ * the physical eraseblock is not directly moved from the @wl->free tree to the
+ * @wl->used tree. There is a protection queue in between where this
+ * physical eraseblock is temporarily stored (@wl->pq).
+ *
+ * All this protection stuff is needed because:
+ *  o we don't want to move physical eraseblocks just after we have given them
+ *    to the user; instead, we first want to let users fill them up with data;
+ *
+ *  o there is a chance that the user will put the physical eraseblock very
+ *    soon, so it makes sense not to move it for some time, but wait.
  *
- * If the WL unit fails to erase a physical eraseblock, it marks it as bad.
+ * Physical eraseblocks stay protected only for limited time. But the "time" is
+ * measured in erase cycles in this case. This is implemented with help of the
+ * protection queue. Eraseblocks are put to the tail of this queue when they
+ * are returned by the 'ubi_wl_get_peb()', and eraseblocks are removed from the
+ * head of the queue on each erase operation (for any eraseblock). So the
+ * length of the queue defines how may (global) erase cycles PEBs are protected.
  *
- * This unit is also responsible for scrubbing. If a bit-flip is detected in a
- * physical eraseblock, it has to be moved. Technically this is the same as
- * moving it for wear-leveling reasons.
+ * To put it differently, each physical eraseblock has 2 main states: free and
+ * 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).
  *
- * As it was said, for the UBI unit all physical eraseblocks are either "free"
- * or "used". Free eraseblock are kept in the @wl->free RB-tree, while used
- * eraseblocks are kept in a set of different RB-trees: @wl->used,
- * @wl->prot.pnum, @wl->prot.aec, and @wl->scrub.
+ * Depending on the sub-state, wear-leveling entries of the used physical
+ * eraseblocks may be kept in one of those structures.
  *
  * Note, in this implementation, we keep a small in-RAM object for each physical
  * eraseblock. This is surely not a scalable solution. But it appears to be good
  * enough for moderately large flashes and it is simple. In future, one may
- * re-work this unit and make it more scalable.
+ * re-work this sub-system and make it more scalable.
  *
- * At the moment this unit does not utilize the sequence number, which was
- * introduced relatively recently. But it would be wise to do this because the
- * sequence number of a logical eraseblock characterizes how old is it. For
+ * At the moment this sub-system does not utilize the sequence number, which
+ * was introduced relatively recently. But it would be wise to do this because
+ * the sequence number of a logical eraseblock characterizes how old is it. For
  * example, when we move a PEB with low erase counter, and we need to pick the
  * target PEB, we pick a PEB with the highest EC if our PEB is "old" and we
  * pick target PEB with an average EC if our PEB is not very "old". This is a
- * room for future re-works of the WL unit.
- *
- * FIXME: looks too complex, should be simplified (later).
+ * room for future re-works of the WL sub-system.
  */
 
-#ifdef UBI_LINUX
+#define __UBOOT__
+#ifndef __UBOOT__
 #include <linux/slab.h>
 #include <linux/crc32.h>
 #include <linux/freezer.h>
 #include <linux/kthread.h>
+#else
+#include <ubi_uboot.h>
 #endif
 
-#include <ubi_uboot.h>
 #include "ubi.h"
 
 /* Number of physical eraseblocks reserved for wear-leveling purposes */
 #define WL_RESERVED_PEBS 1
 
-/*
- * How many erase cycles are short term, unknown, and long term physical
- * eraseblocks protected.
- */
-#define ST_PROTECTION 16
-#define U_PROTECTION  10
-#define LT_PROTECTION 4
-
 /*
  * Maximum difference between two erase counters. If this threshold is
- * exceeded, the WL unit starts moving data from used physical eraseblocks with
- * low erase counter to free physical eraseblocks with high erase counter.
+ * exceeded, the WL sub-system starts moving data from used physical
+ * eraseblocks with low erase counter to free physical eraseblocks with high
+ * erase counter.
  */
 #define UBI_WL_THRESHOLD CONFIG_MTD_UBI_WL_THRESHOLD
 
 /*
- * When a physical eraseblock is moved, the WL unit has to pick the target
+ * When a physical eraseblock is moved, the WL sub-system has to pick the target
  * physical eraseblock to move to. The simplest way would be just to pick the
  * one with the highest erase counter. But in certain workloads this could lead
  * to an unlimited wear of one or few physical eraseblock. Indeed, imagine a
  * situation when the picked physical eraseblock is constantly erased after the
  * data is written to it. So, we have a constant which limits the highest erase
- * counter of the free physical eraseblock to pick. Namely, the WL unit does
- * not pick eraseblocks with erase counter greater then the lowest erase
+ * counter of the free physical eraseblock to pick. Namely, the WL sub-system
+ * does not pick eraseblocks with erase counter greater than the lowest erase
  * counter plus %WL_FREE_MAX_DIFF.
  */
 #define WL_FREE_MAX_DIFF (2*UBI_WL_THRESHOLD)
  */
 #define WL_MAX_FAILURES 32
 
+static int self_check_ec(struct ubi_device *ubi, int pnum, int ec);
+static int self_check_in_wl_tree(const struct ubi_device *ubi,
+                                struct ubi_wl_entry *e, struct rb_root *root);
+static int self_check_in_pq(const struct ubi_device *ubi,
+                           struct ubi_wl_entry *e);
+
+#ifdef CONFIG_MTD_UBI_FASTMAP
+#ifndef __UBOOT__
 /**
- * struct ubi_wl_prot_entry - PEB protection entry.
- * @rb_pnum: link in the @wl->prot.pnum RB-tree
- * @rb_aec: link in the @wl->prot.aec RB-tree
- * @abs_ec: the absolute erase counter value when the protection ends
- * @e: the wear-leveling entry of the physical eraseblock under protection
- *
- * When the WL unit returns a physical eraseblock, the physical eraseblock is
- * protected from being moved for some "time". For this reason, the physical
- * eraseblock is not directly moved from the @wl->free tree to the @wl->used
- * tree. There is one more tree in between where this physical eraseblock is
- * temporarily stored (@wl->prot).
- *
- * All this protection stuff is needed because:
- *  o we don't want to move physical eraseblocks just after we have given them
- *    to the user; instead, we first want to let users fill them up with data;
- *
- *  o there is a chance that the user will put the physical eraseblock very
- *    soon, so it makes sense not to move it for some time, but wait; this is
- *    especially important in case of "short term" physical eraseblocks.
- *
- * Physical eraseblocks stay protected only for limited time. But the "time" is
- * measured in erase cycles in this case. This is implemented with help of the
- * absolute erase counter (@wl->abs_ec). When it reaches certain value, the
- * physical eraseblocks are moved from the protection trees (@wl->prot.*) to
- * the @wl->used tree.
- *
- * Protected physical eraseblocks are searched by physical eraseblock number
- * (when they are put) and by the absolute erase counter (to check if it is
- * time to move them to the @wl->used tree). So there are actually 2 RB-trees
- * storing the protected physical eraseblocks: @wl->prot.pnum and
- * @wl->prot.aec. They are referred to as the "protection" trees. The
- * first one is indexed by the physical eraseblock number. The second one is
- * indexed by the absolute erase counter. Both trees store
- * &struct ubi_wl_prot_entry objects.
- *
- * Each physical eraseblock has 2 main states: free and 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 temporarily prohibited (@wl->prot.pnum and
- * @wl->prot.aec trees);
- * o scrubbing is needed (@wl->scrub tree).
- *
- * Depending on the sub-state, wear-leveling entries of the used physical
- * eraseblocks may be kept in one of those trees.
+ * update_fastmap_work_fn - calls ubi_update_fastmap from a work queue
+ * @wrk: the work description object
  */
-struct ubi_wl_prot_entry {
-       struct rb_node rb_pnum;
-       struct rb_node rb_aec;
-       unsigned long long abs_ec;
-       struct ubi_wl_entry *e;
-};
+static void update_fastmap_work_fn(struct work_struct *wrk)
+{
+       struct ubi_device *ubi = container_of(wrk, struct ubi_device, fm_work);
+       ubi_update_fastmap(ubi);
+}
+#endif
 
 /**
- * struct ubi_work - UBI work description data structure.
- * @list: a link in the list of pending works
- * @func: worker function
- * @priv: private data of the worker function
- *
- * @e: physical eraseblock to erase
- * @torture: if the physical eraseblock has to be tortured
- *
- * The @func pointer points to the worker function. If the @cancel argument is
- * not zero, the worker has to free the resources and exit immediately. The
- * worker has to return zero in case of success and a negative error code in
- * case of failure.
+ *  ubi_ubi_is_fm_block - returns 1 if a PEB is currently used in a fastmap.
+ *  @ubi: UBI device description object
+ *  @pnum: the to be checked PEB
  */
-struct ubi_work {
-       struct list_head list;
-       int (*func)(struct ubi_device *ubi, struct ubi_work *wrk, int cancel);
-       /* The below fields are only relevant to erasure works */
-       struct ubi_wl_entry *e;
-       int torture;
-};
+static int ubi_is_fm_block(struct ubi_device *ubi, int pnum)
+{
+       int i;
 
-#ifdef CONFIG_MTD_UBI_DEBUG_PARANOID
-static int paranoid_check_ec(struct ubi_device *ubi, int pnum, int ec);
-static int paranoid_check_in_wl_tree(struct ubi_wl_entry *e,
-                                    struct rb_root *root);
+       if (!ubi->fm)
+               return 0;
+
+       for (i = 0; i < ubi->fm->used_blocks; i++)
+               if (ubi->fm->e[i]->pnum == pnum)
+                       return 1;
+
+       return 0;
+}
 #else
-#define paranoid_check_ec(ubi, pnum, ec) 0
-#define paranoid_check_in_wl_tree(e, root)
+static int ubi_is_fm_block(struct ubi_device *ubi, int pnum)
+{
+       return 0;
+}
 #endif
 
 /**
@@ -222,7 +189,7 @@ static void wl_tree_add(struct ubi_wl_entry *e, struct rb_root *root)
                struct ubi_wl_entry *e1;
 
                parent = *p;
-               e1 = rb_entry(parent, struct ubi_wl_entry, rb);
+               e1 = rb_entry(parent, struct ubi_wl_entry, u.rb);
 
                if (e->ec < e1->ec)
                        p = &(*p)->rb_left;
@@ -237,8 +204,8 @@ static void wl_tree_add(struct ubi_wl_entry *e, struct rb_root *root)
                }
        }
 
-       rb_link_node(&e->rb, parent, p);
-       rb_insert_color(&e->rb, root);
+       rb_link_node(&e->u.rb, parent, p);
+       rb_insert_color(&e->u.rb, root);
 }
 
 /**
@@ -301,18 +268,16 @@ static int produce_free_peb(struct ubi_device *ubi)
 {
        int err;
 
-       spin_lock(&ubi->wl_lock);
        while (!ubi->free.rb_node) {
                spin_unlock(&ubi->wl_lock);
 
                dbg_wl("do one work synchronously");
                err = do_work(ubi);
-               if (err)
-                       return err;
 
                spin_lock(&ubi->wl_lock);
+               if (err)
+                       return err;
        }
-       spin_unlock(&ubi->wl_lock);
 
        return 0;
 }
@@ -333,7 +298,7 @@ static int in_wl_tree(struct ubi_wl_entry *e, struct rb_root *root)
        while (p) {
                struct ubi_wl_entry *e1;
 
-               e1 = rb_entry(p, struct ubi_wl_entry, rb);
+               e1 = rb_entry(p, struct ubi_wl_entry, u.rb);
 
                if (e->pnum == e1->pnum) {
                        ubi_assert(e == e1);
@@ -357,223 +322,406 @@ static int in_wl_tree(struct ubi_wl_entry *e, struct rb_root *root)
 }
 
 /**
- * prot_tree_add - add physical eraseblock to protection trees.
+ * prot_queue_add - add physical eraseblock to the protection queue.
  * @ubi: UBI device description object
  * @e: the physical eraseblock to add
- * @pe: protection entry object to use
- * @abs_ec: absolute erase counter value when this physical eraseblock has
- * to be removed from the protection trees.
  *
- * @wl->lock has to be locked.
+ * This function adds @e to the tail of the protection queue @ubi->pq, where
+ * @e will stay for %UBI_PROT_QUEUE_LEN erase operations and will be
+ * temporarily protected from the wear-leveling worker. Note, @wl->lock has to
+ * be locked.
  */
-static void prot_tree_add(struct ubi_device *ubi, struct ubi_wl_entry *e,
-                         struct ubi_wl_prot_entry *pe, int abs_ec)
+static void prot_queue_add(struct ubi_device *ubi, struct ubi_wl_entry *e)
 {
-       struct rb_node **p, *parent = NULL;
-       struct ubi_wl_prot_entry *pe1;
-
-       pe->e = e;
-       pe->abs_ec = ubi->abs_ec + abs_ec;
-
-       p = &ubi->prot.pnum.rb_node;
-       while (*p) {
-               parent = *p;
-               pe1 = rb_entry(parent, struct ubi_wl_prot_entry, rb_pnum);
+       int pq_tail = ubi->pq_head - 1;
 
-               if (e->pnum < pe1->e->pnum)
-                       p = &(*p)->rb_left;
-               else
-                       p = &(*p)->rb_right;
-       }
-       rb_link_node(&pe->rb_pnum, parent, p);
-       rb_insert_color(&pe->rb_pnum, &ubi->prot.pnum);
-
-       p = &ubi->prot.aec.rb_node;
-       parent = NULL;
-       while (*p) {
-               parent = *p;
-               pe1 = rb_entry(parent, struct ubi_wl_prot_entry, rb_aec);
-
-               if (pe->abs_ec < pe1->abs_ec)
-                       p = &(*p)->rb_left;
-               else
-                       p = &(*p)->rb_right;
-       }
-       rb_link_node(&pe->rb_aec, parent, p);
-       rb_insert_color(&pe->rb_aec, &ubi->prot.aec);
+       if (pq_tail < 0)
+               pq_tail = UBI_PROT_QUEUE_LEN - 1;
+       ubi_assert(pq_tail >= 0 && pq_tail < UBI_PROT_QUEUE_LEN);
+       list_add_tail(&e->u.list, &ubi->pq[pq_tail]);
+       dbg_wl("added PEB %d EC %d to the protection queue", e->pnum, e->ec);
 }
 
 /**
  * find_wl_entry - find wear-leveling entry closest to certain erase counter.
+ * @ubi: UBI device description object
  * @root: the RB-tree where to look for
- * @max: highest possible erase counter
+ * @diff: maximum possible difference from the smallest erase counter
  *
  * This function looks for a wear leveling entry with erase counter closest to
- * @max and less then @max.
+ * min + @diff, where min is the smallest erase counter.
  */
-static struct ubi_wl_entry *find_wl_entry(struct rb_root *root, int max)
+static struct ubi_wl_entry *find_wl_entry(struct ubi_device *ubi,
+                                         struct rb_root *root, int diff)
 {
        struct rb_node *p;
-       struct ubi_wl_entry *e;
+       struct ubi_wl_entry *e, *prev_e = NULL;
+       int max;
 
-       e = rb_entry(rb_first(root), struct ubi_wl_entry, rb);
-       max += e->ec;
+       e = rb_entry(rb_first(root), struct ubi_wl_entry, u.rb);
+       max = e->ec + diff;
 
        p = root->rb_node;
        while (p) {
                struct ubi_wl_entry *e1;
 
-               e1 = rb_entry(p, struct ubi_wl_entry, rb);
+               e1 = rb_entry(p, struct ubi_wl_entry, u.rb);
                if (e1->ec >= max)
                        p = p->rb_left;
                else {
                        p = p->rb_right;
+                       prev_e = e;
                        e = e1;
                }
        }
 
+       /* If no fastmap has been written and this WL entry can be used
+        * as anchor PEB, hold it back and return the second best WL entry
+        * such that fastmap can use the anchor PEB later. */
+       if (prev_e && !ubi->fm_disabled &&
+           !ubi->fm && e->pnum < UBI_FM_MAX_START)
+               return prev_e;
+
        return e;
 }
 
 /**
- * ubi_wl_get_peb - get a physical eraseblock.
+ * find_mean_wl_entry - find wear-leveling entry with medium erase counter.
  * @ubi: UBI device description object
- * @dtype: type of data which will be stored in this physical eraseblock
+ * @root: the RB-tree where to look for
  *
- * This function returns a physical eraseblock in case of success and a
- * negative error code in case of failure. Might sleep.
+ * This function looks for a wear leveling entry with medium erase counter,
+ * but not greater or equivalent than the lowest erase counter plus
+ * %WL_FREE_MAX_DIFF/2.
  */
-int ubi_wl_get_peb(struct ubi_device *ubi, int dtype)
+static struct ubi_wl_entry *find_mean_wl_entry(struct ubi_device *ubi,
+                                              struct rb_root *root)
 {
-       int err, protect, medium_ec;
        struct ubi_wl_entry *e, *first, *last;
-       struct ubi_wl_prot_entry *pe;
 
-       ubi_assert(dtype == UBI_LONGTERM || dtype == UBI_SHORTTERM ||
-                  dtype == UBI_UNKNOWN);
+       first = rb_entry(rb_first(root), struct ubi_wl_entry, u.rb);
+       last = rb_entry(rb_last(root), struct ubi_wl_entry, u.rb);
 
-       pe = kmalloc(sizeof(struct ubi_wl_prot_entry), GFP_NOFS);
-       if (!pe)
-               return -ENOMEM;
+       if (last->ec - first->ec < WL_FREE_MAX_DIFF) {
+               e = rb_entry(root->rb_node, struct ubi_wl_entry, u.rb);
+
+#ifdef CONFIG_MTD_UBI_FASTMAP
+               /* If no fastmap has been written and this WL entry can be used
+                * as anchor PEB, hold it back and return the second best
+                * WL entry such that fastmap can use the anchor PEB later. */
+               if (e && !ubi->fm_disabled && !ubi->fm &&
+                   e->pnum < UBI_FM_MAX_START)
+                       e = rb_entry(rb_next(root->rb_node),
+                                    struct ubi_wl_entry, u.rb);
+#endif
+       } else
+               e = find_wl_entry(ubi, root, WL_FREE_MAX_DIFF/2);
+
+       return e;
+}
+
+#ifdef CONFIG_MTD_UBI_FASTMAP
+/**
+ * find_anchor_wl_entry - find wear-leveling entry to used as anchor PEB.
+ * @root: the RB-tree where to look for
+ */
+static struct ubi_wl_entry *find_anchor_wl_entry(struct rb_root *root)
+{
+       struct rb_node *p;
+       struct ubi_wl_entry *e, *victim = NULL;
+       int max_ec = UBI_MAX_ERASECOUNTER;
+
+       ubi_rb_for_each_entry(p, e, root, u.rb) {
+               if (e->pnum < UBI_FM_MAX_START && e->ec < max_ec) {
+                       victim = e;
+                       max_ec = e->ec;
+               }
+       }
+
+       return victim;
+}
+
+static int anchor_pebs_avalible(struct rb_root *root)
+{
+       struct rb_node *p;
+       struct ubi_wl_entry *e;
+
+       ubi_rb_for_each_entry(p, e, root, u.rb)
+               if (e->pnum < UBI_FM_MAX_START)
+                       return 1;
+
+       return 0;
+}
+
+/**
+ * ubi_wl_get_fm_peb - find a physical erase block with a given maximal number.
+ * @ubi: UBI device description object
+ * @anchor: This PEB will be used as anchor PEB by fastmap
+ *
+ * The function returns a physical erase block with a given maximal number
+ * and removes it from the wl subsystem.
+ * Must be called with wl_lock held!
+ */
+struct ubi_wl_entry *ubi_wl_get_fm_peb(struct ubi_device *ubi, int anchor)
+{
+       struct ubi_wl_entry *e = NULL;
+
+       if (!ubi->free.rb_node || (ubi->free_count - ubi->beb_rsvd_pebs < 1))
+               goto out;
+
+       if (anchor)
+               e = find_anchor_wl_entry(&ubi->free);
+       else
+               e = find_mean_wl_entry(ubi, &ubi->free);
+
+       if (!e)
+               goto out;
+
+       self_check_in_wl_tree(ubi, e, &ubi->free);
+
+       /* remove it from the free list,
+        * the wl subsystem does no longer know this erase block */
+       rb_erase(&e->u.rb, &ubi->free);
+       ubi->free_count--;
+out:
+       return e;
+}
+#endif
+
+/**
+ * __wl_get_peb - get a physical eraseblock.
+ * @ubi: UBI device description object
+ *
+ * This function returns a physical eraseblock in case of success and a
+ * negative error code in case of failure.
+ */
+static int __wl_get_peb(struct ubi_device *ubi)
+{
+       int err;
+       struct ubi_wl_entry *e;
 
 retry:
-       spin_lock(&ubi->wl_lock);
        if (!ubi->free.rb_node) {
                if (ubi->works_count == 0) {
-                       ubi_assert(list_empty(&ubi->works));
                        ubi_err("no free eraseblocks");
-                       spin_unlock(&ubi->wl_lock);
-                       kfree(pe);
+                       ubi_assert(list_empty(&ubi->works));
                        return -ENOSPC;
                }
-               spin_unlock(&ubi->wl_lock);
 
                err = produce_free_peb(ubi);
-               if (err < 0) {
-                       kfree(pe);
+               if (err < 0)
                        return err;
-               }
                goto retry;
        }
 
-       switch (dtype) {
-               case UBI_LONGTERM:
-                       /*
-                        * For long term data we pick a physical eraseblock
-                        * with high erase counter. But the highest erase
-                        * counter we can pick is bounded by the the lowest
-                        * erase counter plus %WL_FREE_MAX_DIFF.
-                        */
-                       e = find_wl_entry(&ubi->free, WL_FREE_MAX_DIFF);
-                       protect = LT_PROTECTION;
-                       break;
-               case UBI_UNKNOWN:
-                       /*
-                        * For unknown data we pick a physical eraseblock with
-                        * medium erase counter. But we by no means can pick a
-                        * physical eraseblock with erase counter greater or
-                        * equivalent than the lowest erase counter plus
-                        * %WL_FREE_MAX_DIFF.
-                        */
-                       first = rb_entry(rb_first(&ubi->free),
-                                        struct ubi_wl_entry, rb);
-                       last = rb_entry(rb_last(&ubi->free),
-                                       struct ubi_wl_entry, rb);
-
-                       if (last->ec - first->ec < WL_FREE_MAX_DIFF)
-                               e = rb_entry(ubi->free.rb_node,
-                                               struct ubi_wl_entry, rb);
-                       else {
-                               medium_ec = (first->ec + WL_FREE_MAX_DIFF)/2;
-                               e = find_wl_entry(&ubi->free, medium_ec);
-                       }
-                       protect = U_PROTECTION;
-                       break;
-               case UBI_SHORTTERM:
-                       /*
-                        * For short term data we pick a physical eraseblock
-                        * with the lowest erase counter as we expect it will
-                        * be erased soon.
-                        */
-                       e = rb_entry(rb_first(&ubi->free),
-                                    struct ubi_wl_entry, rb);
-                       protect = ST_PROTECTION;
-                       break;
-               default:
-                       protect = 0;
-                       e = NULL;
-                       BUG();
+       e = find_mean_wl_entry(ubi, &ubi->free);
+       if (!e) {
+               ubi_err("no free eraseblocks");
+               return -ENOSPC;
        }
 
+       self_check_in_wl_tree(ubi, e, &ubi->free);
+
        /*
-        * Move the physical eraseblock to the protection trees where it will
+        * Move the physical eraseblock to the protection queue where it will
         * be protected from being moved for some time.
         */
-       paranoid_check_in_wl_tree(e, &ubi->free);
-       rb_erase(&e->rb, &ubi->free);
-       prot_tree_add(ubi, e, pe, protect);
+       rb_erase(&e->u.rb, &ubi->free);
+       ubi->free_count--;
+       dbg_wl("PEB %d EC %d", e->pnum, e->ec);
+#ifndef CONFIG_MTD_UBI_FASTMAP
+       /* We have to enqueue e only if fastmap is disabled,
+        * is fastmap enabled prot_queue_add() will be called by
+        * ubi_wl_get_peb() after removing e from the pool. */
+       prot_queue_add(ubi, e);
+#endif
+       return e->pnum;
+}
 
-       dbg_wl("PEB %d EC %d, protection %d", e->pnum, e->ec, protect);
-       spin_unlock(&ubi->wl_lock);
+#ifdef CONFIG_MTD_UBI_FASTMAP
+/**
+ * return_unused_pool_pebs - returns unused PEB to the free tree.
+ * @ubi: UBI device description object
+ * @pool: fastmap pool description object
+ */
+static void return_unused_pool_pebs(struct ubi_device *ubi,
+                                   struct ubi_fm_pool *pool)
+{
+       int i;
+       struct ubi_wl_entry *e;
 
-       return e->pnum;
+       for (i = pool->used; i < pool->size; i++) {
+               e = ubi->lookuptbl[pool->pebs[i]];
+               wl_tree_add(e, &ubi->free);
+               ubi->free_count++;
+       }
 }
 
 /**
- * prot_tree_del - remove a physical eraseblock from the protection trees
+ * refill_wl_pool - refills all the fastmap pool used by the
+ * WL sub-system.
  * @ubi: UBI device description object
- * @pnum: the physical eraseblock to remove
+ */
+static void refill_wl_pool(struct ubi_device *ubi)
+{
+       struct ubi_wl_entry *e;
+       struct ubi_fm_pool *pool = &ubi->fm_wl_pool;
+
+       return_unused_pool_pebs(ubi, pool);
+
+       for (pool->size = 0; pool->size < pool->max_size; pool->size++) {
+               if (!ubi->free.rb_node ||
+                  (ubi->free_count - ubi->beb_rsvd_pebs < 5))
+                       break;
+
+               e = find_wl_entry(ubi, &ubi->free, WL_FREE_MAX_DIFF);
+               self_check_in_wl_tree(ubi, e, &ubi->free);
+               rb_erase(&e->u.rb, &ubi->free);
+               ubi->free_count--;
+
+               pool->pebs[pool->size] = e->pnum;
+       }
+       pool->used = 0;
+}
+
+/**
+ * refill_wl_user_pool - refills all the fastmap pool used by ubi_wl_get_peb.
+ * @ubi: UBI device description object
+ */
+static void refill_wl_user_pool(struct ubi_device *ubi)
+{
+       struct ubi_fm_pool *pool = &ubi->fm_pool;
+
+       return_unused_pool_pebs(ubi, pool);
+
+       for (pool->size = 0; pool->size < pool->max_size; pool->size++) {
+               pool->pebs[pool->size] = __wl_get_peb(ubi);
+               if (pool->pebs[pool->size] < 0)
+                       break;
+       }
+       pool->used = 0;
+}
+
+/**
+ * ubi_refill_pools - refills all fastmap PEB pools.
+ * @ubi: UBI device description object
+ */
+void ubi_refill_pools(struct ubi_device *ubi)
+{
+       spin_lock(&ubi->wl_lock);
+       refill_wl_pool(ubi);
+       refill_wl_user_pool(ubi);
+       spin_unlock(&ubi->wl_lock);
+}
+
+/* ubi_wl_get_peb - works exaclty like __wl_get_peb but keeps track of
+ * the fastmap pool.
+ */
+int ubi_wl_get_peb(struct ubi_device *ubi)
+{
+       int ret;
+       struct ubi_fm_pool *pool = &ubi->fm_pool;
+       struct ubi_fm_pool *wl_pool = &ubi->fm_wl_pool;
+
+       if (!pool->size || !wl_pool->size || pool->used == pool->size ||
+           wl_pool->used == wl_pool->size)
+               ubi_update_fastmap(ubi);
+
+       /* we got not a single free PEB */
+       if (!pool->size)
+               ret = -ENOSPC;
+       else {
+               spin_lock(&ubi->wl_lock);
+               ret = pool->pebs[pool->used++];
+               prot_queue_add(ubi, ubi->lookuptbl[ret]);
+               spin_unlock(&ubi->wl_lock);
+       }
+
+       return ret;
+}
+
+/* get_peb_for_wl - returns a PEB to be used internally by the WL sub-system.
  *
- * This function returns PEB @pnum from the protection trees and returns zero
- * in case of success and %-ENODEV if the PEB was not found in the protection
- * trees.
+ * @ubi: UBI device description object
  */
-static int prot_tree_del(struct ubi_device *ubi, int pnum)
+static struct ubi_wl_entry *get_peb_for_wl(struct ubi_device *ubi)
 {
-       struct rb_node *p;
-       struct ubi_wl_prot_entry *pe = NULL;
+       struct ubi_fm_pool *pool = &ubi->fm_wl_pool;
+       int pnum;
+
+       if (pool->used == pool->size || !pool->size) {
+               /* We cannot update the fastmap here because this
+                * function is called in atomic context.
+                * Let's fail here and refill/update it as soon as possible. */
+#ifndef __UBOOT__
+               schedule_work(&ubi->fm_work);
+#else
+               /* In U-Boot we must call this directly */
+               ubi_update_fastmap(ubi);
+#endif
+               return NULL;
+       } else {
+               pnum = pool->pebs[pool->used++];
+               return ubi->lookuptbl[pnum];
+       }
+}
+#else
+static struct ubi_wl_entry *get_peb_for_wl(struct ubi_device *ubi)
+{
+       struct ubi_wl_entry *e;
 
-       p = ubi->prot.pnum.rb_node;
-       while (p) {
+       e = find_wl_entry(ubi, &ubi->free, WL_FREE_MAX_DIFF);
+       self_check_in_wl_tree(ubi, e, &ubi->free);
+       ubi->free_count--;
+       ubi_assert(ubi->free_count >= 0);
+       rb_erase(&e->u.rb, &ubi->free);
 
-               pe = rb_entry(p, struct ubi_wl_prot_entry, rb_pnum);
+       return e;
+}
 
-               if (pnum == pe->e->pnum)
-                       goto found;
+int ubi_wl_get_peb(struct ubi_device *ubi)
+{
+       int peb, err;
 
-               if (pnum < pe->e->pnum)
-                       p = p->rb_left;
-               else
-                       p = p->rb_right;
+       spin_lock(&ubi->wl_lock);
+       peb = __wl_get_peb(ubi);
+       spin_unlock(&ubi->wl_lock);
+
+       if (peb < 0)
+               return peb;
+
+       err = ubi_self_check_all_ff(ubi, peb, ubi->vid_hdr_aloffset,
+                                   ubi->peb_size - ubi->vid_hdr_aloffset);
+       if (err) {
+               ubi_err("new PEB %d does not contain all 0xFF bytes", peb);
+               return err;
        }
 
-       return -ENODEV;
+       return peb;
+}
+#endif
+
+/**
+ * prot_queue_del - remove a physical eraseblock from the protection queue.
+ * @ubi: UBI device description object
+ * @pnum: the physical eraseblock to remove
+ *
+ * This function deletes PEB @pnum from the protection queue and returns zero
+ * in case of success and %-ENODEV if the PEB was not found.
+ */
+static int prot_queue_del(struct ubi_device *ubi, int pnum)
+{
+       struct ubi_wl_entry *e;
+
+       e = ubi->lookuptbl[pnum];
+       if (!e)
+               return -ENODEV;
 
-found:
-       ubi_assert(pe->e->pnum == pnum);
-       rb_erase(&pe->rb_aec, &ubi->prot.aec);
-       rb_erase(&pe->rb_pnum, &ubi->prot.pnum);
-       kfree(pe);
+       if (self_check_in_pq(ubi, e))
+               return -ENODEV;
+
+       list_del(&e->u.list);
+       dbg_wl("deleted PEB %d from the protection queue", e->pnum);
        return 0;
 }
 
@@ -586,7 +734,8 @@ found:
  * This function returns zero in case of success and a negative error code in
  * case of failure.
  */
-static int sync_erase(struct ubi_device *ubi, struct ubi_wl_entry *e, int torture)
+static int sync_erase(struct ubi_device *ubi, struct ubi_wl_entry *e,
+                     int torture)
 {
        int err;
        struct ubi_ec_hdr *ec_hdr;
@@ -594,8 +743,8 @@ static int sync_erase(struct ubi_device *ubi, struct ubi_wl_entry *e, int tortur
 
        dbg_wl("erase PEB %d, old EC %llu", e->pnum, ec);
 
-       err = paranoid_check_ec(ubi, e->pnum, e->ec);
-       if (err > 0)
+       err = self_check_ec(ubi, e->pnum, e->ec);
+       if (err)
                return -EINVAL;
 
        ec_hdr = kzalloc(ubi->ec_hdr_alsize, GFP_NOFS);
@@ -638,100 +787,213 @@ out_free:
 }
 
 /**
- * check_protection_over - check if it is time to stop protecting some
- * physical eraseblocks.
+ * serve_prot_queue - check if it is time to stop protecting PEBs.
  * @ubi: UBI device description object
  *
- * This function is called after each erase operation, when the absolute erase
- * counter is incremented, to check if some physical eraseblock  have not to be
- * protected any longer. These physical eraseblocks are moved from the
- * protection trees to the used tree.
+ * This function is called after each erase operation and removes PEBs from the
+ * tail of the protection queue. These PEBs have been protected for long enough
+ * and should be moved to the used tree.
  */
-static void check_protection_over(struct ubi_device *ubi)
+static void serve_prot_queue(struct ubi_device *ubi)
 {
-       struct ubi_wl_prot_entry *pe;
+       struct ubi_wl_entry *e, *tmp;
+       int count;
 
        /*
         * There may be several protected physical eraseblock to remove,
         * process them all.
         */
-       while (1) {
-               spin_lock(&ubi->wl_lock);
-               if (!ubi->prot.aec.rb_node) {
-                       spin_unlock(&ubi->wl_lock);
-                       break;
-               }
-
-               pe = rb_entry(rb_first(&ubi->prot.aec),
-                             struct ubi_wl_prot_entry, rb_aec);
+repeat:
+       count = 0;
+       spin_lock(&ubi->wl_lock);
+       list_for_each_entry_safe(e, tmp, &ubi->pq[ubi->pq_head], u.list) {
+               dbg_wl("PEB %d EC %d protection over, move to used tree",
+                       e->pnum, e->ec);
 
-               if (pe->abs_ec > ubi->abs_ec) {
+               list_del(&e->u.list);
+               wl_tree_add(e, &ubi->used);
+               if (count++ > 32) {
+                       /*
+                        * Let's be nice and avoid holding the spinlock for
+                        * too long.
+                        */
                        spin_unlock(&ubi->wl_lock);
-                       break;
+                       cond_resched();
+                       goto repeat;
                }
-
-               dbg_wl("PEB %d protection over, abs_ec %llu, PEB abs_ec %llu",
-                      pe->e->pnum, ubi->abs_ec, pe->abs_ec);
-               rb_erase(&pe->rb_aec, &ubi->prot.aec);
-               rb_erase(&pe->rb_pnum, &ubi->prot.pnum);
-               wl_tree_add(pe->e, &ubi->used);
-               spin_unlock(&ubi->wl_lock);
-
-               kfree(pe);
-               cond_resched();
        }
+
+       ubi->pq_head += 1;
+       if (ubi->pq_head == UBI_PROT_QUEUE_LEN)
+               ubi->pq_head = 0;
+       ubi_assert(ubi->pq_head >= 0 && ubi->pq_head < UBI_PROT_QUEUE_LEN);
+       spin_unlock(&ubi->wl_lock);
 }
 
 /**
- * schedule_ubi_work - schedule a work.
+ * __schedule_ubi_work - schedule a work.
  * @ubi: UBI device description object
  * @wrk: the work to schedule
  *
- * This function enqueues a work defined by @wrk to the tail of the pending
- * works list.
+ * This function adds a work defined by @wrk to the tail of the pending works
+ * list. Can only be used of ubi->work_sem is already held in read mode!
  */
-static void schedule_ubi_work(struct ubi_device *ubi, struct ubi_work *wrk)
+static void __schedule_ubi_work(struct ubi_device *ubi, struct ubi_work *wrk)
 {
        spin_lock(&ubi->wl_lock);
        list_add_tail(&wrk->list, &ubi->works);
        ubi_assert(ubi->works_count >= 0);
        ubi->works_count += 1;
-       if (ubi->thread_enabled)
+#ifndef __UBOOT__
+       if (ubi->thread_enabled && !ubi_dbg_is_bgt_disabled(ubi))
                wake_up_process(ubi->bgt_thread);
+#else
+       /*
+        * U-Boot special: We have no bgt_thread in U-Boot!
+        * So just call do_work() here directly.
+        */
+       do_work(ubi);
+#endif
        spin_unlock(&ubi->wl_lock);
 }
 
-static int erase_worker(struct ubi_device *ubi, struct ubi_work *wl_wrk,
-                       int cancel);
-
 /**
- * schedule_erase - schedule an erase work.
+ * schedule_ubi_work - schedule a work.
+ * @ubi: UBI device description object
+ * @wrk: the work to schedule
+ *
+ * This function adds a work defined by @wrk to the tail of the pending works
+ * list.
+ */
+static void schedule_ubi_work(struct ubi_device *ubi, struct ubi_work *wrk)
+{
+       down_read(&ubi->work_sem);
+       __schedule_ubi_work(ubi, wrk);
+       up_read(&ubi->work_sem);
+}
+
+static int erase_worker(struct ubi_device *ubi, struct ubi_work *wl_wrk,
+                       int cancel);
+
+#ifdef CONFIG_MTD_UBI_FASTMAP
+/**
+ * ubi_is_erase_work - checks whether a work is erase work.
+ * @wrk: The work object to be checked
+ */
+int ubi_is_erase_work(struct ubi_work *wrk)
+{
+       return wrk->func == erase_worker;
+}
+#endif
+
+/**
+ * schedule_erase - schedule an erase work.
+ * @ubi: UBI device description object
+ * @e: the WL entry of the physical eraseblock to erase
+ * @vol_id: the volume ID that last used this PEB
+ * @lnum: the last used logical eraseblock number for the PEB
+ * @torture: if the physical eraseblock has to be tortured
+ *
+ * This function returns zero in case of success and a %-ENOMEM in case of
+ * failure.
+ */
+static int schedule_erase(struct ubi_device *ubi, struct ubi_wl_entry *e,
+                         int vol_id, int lnum, int torture)
+{
+       struct ubi_work *wl_wrk;
+
+       ubi_assert(e);
+       ubi_assert(!ubi_is_fm_block(ubi, e->pnum));
+
+       dbg_wl("schedule erasure of PEB %d, EC %d, torture %d",
+              e->pnum, e->ec, torture);
+
+       wl_wrk = kmalloc(sizeof(struct ubi_work), GFP_NOFS);
+       if (!wl_wrk)
+               return -ENOMEM;
+
+       wl_wrk->func = &erase_worker;
+       wl_wrk->e = e;
+       wl_wrk->vol_id = vol_id;
+       wl_wrk->lnum = lnum;
+       wl_wrk->torture = torture;
+
+       schedule_ubi_work(ubi, wl_wrk);
+       return 0;
+}
+
+/**
+ * do_sync_erase - run the erase worker synchronously.
  * @ubi: UBI device description object
  * @e: the WL entry of the physical eraseblock to erase
+ * @vol_id: the volume ID that last used this PEB
+ * @lnum: the last used logical eraseblock number for the PEB
  * @torture: if the physical eraseblock has to be tortured
  *
- * This function returns zero in case of success and a %-ENOMEM in case of
- * failure.
  */
-static int schedule_erase(struct ubi_device *ubi, struct ubi_wl_entry *e,
-                         int torture)
+static int do_sync_erase(struct ubi_device *ubi, struct ubi_wl_entry *e,
+                        int vol_id, int lnum, int torture)
 {
        struct ubi_work *wl_wrk;
 
-       dbg_wl("schedule erasure of PEB %d, EC %d, torture %d",
-              e->pnum, e->ec, torture);
+       dbg_wl("sync erase of PEB %i", e->pnum);
 
        wl_wrk = kmalloc(sizeof(struct ubi_work), GFP_NOFS);
        if (!wl_wrk)
                return -ENOMEM;
 
-       wl_wrk->func = &erase_worker;
        wl_wrk->e = e;
+       wl_wrk->vol_id = vol_id;
+       wl_wrk->lnum = lnum;
        wl_wrk->torture = torture;
 
-       schedule_ubi_work(ubi, wl_wrk);
-       return 0;
+       return erase_worker(ubi, wl_wrk, 0);
+}
+
+#ifdef CONFIG_MTD_UBI_FASTMAP
+/**
+ * ubi_wl_put_fm_peb - returns a PEB used in a fastmap to the wear-leveling
+ * sub-system.
+ * see: ubi_wl_put_peb()
+ *
+ * @ubi: UBI device description object
+ * @fm_e: physical eraseblock to return
+ * @lnum: the last used logical eraseblock number for the PEB
+ * @torture: if this physical eraseblock has to be tortured
+ */
+int ubi_wl_put_fm_peb(struct ubi_device *ubi, struct ubi_wl_entry *fm_e,
+                     int lnum, int torture)
+{
+       struct ubi_wl_entry *e;
+       int vol_id, pnum = fm_e->pnum;
+
+       dbg_wl("PEB %d", pnum);
+
+       ubi_assert(pnum >= 0);
+       ubi_assert(pnum < ubi->peb_count);
+
+       spin_lock(&ubi->wl_lock);
+       e = ubi->lookuptbl[pnum];
+
+       /* This can happen if we recovered from a fastmap the very
+        * first time and writing now a new one. In this case the wl system
+        * has never seen any PEB used by the original fastmap.
+        */
+       if (!e) {
+               e = fm_e;
+               ubi_assert(e->ec >= 0);
+               ubi->lookuptbl[pnum] = e;
+       } else {
+               e->ec = fm_e->ec;
+               kfree(fm_e);
+       }
+
+       spin_unlock(&ubi->wl_lock);
+
+       vol_id = lnum ? UBI_FM_DATA_VOLUME_ID : UBI_FM_SB_VOLUME_ID;
+       return schedule_erase(ubi, e, vol_id, lnum, torture);
 }
+#endif
 
 /**
  * wear_leveling_worker - wear-leveling worker function.
@@ -746,13 +1008,15 @@ 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, put = 0, scrubbing = 0, protect = 0;
-       struct ubi_wl_prot_entry *uninitialized_var(pe);
+       int err, scrubbing = 0, torture = 0, protect = 0, erroneous = 0;
+       int vol_id = -1, uninitialized_var(lnum);
+#ifdef CONFIG_MTD_UBI_FASTMAP
+       int anchor = wrk->anchor;
+#endif
        struct ubi_wl_entry *e1, *e2;
        struct ubi_vid_hdr *vid_hdr;
 
        kfree(wrk);
-
        if (cancel)
                return 0;
 
@@ -782,36 +1046,62 @@ static int wear_leveling_worker(struct ubi_device *ubi, struct ubi_work *wrk,
                goto out_cancel;
        }
 
+#ifdef CONFIG_MTD_UBI_FASTMAP
+       /* Check whether we need to produce an anchor PEB */
+       if (!anchor)
+               anchor = !anchor_pebs_avalible(&ubi->free);
+
+       if (anchor) {
+               e1 = find_anchor_wl_entry(&ubi->used);
+               if (!e1)
+                       goto out_cancel;
+               e2 = get_peb_for_wl(ubi);
+               if (!e2)
+                       goto out_cancel;
+
+               self_check_in_wl_tree(ubi, e1, &ubi->used);
+               rb_erase(&e1->u.rb, &ubi->used);
+               dbg_wl("anchor-move PEB %d to PEB %d", e1->pnum, e2->pnum);
+       } else if (!ubi->scrub.rb_node) {
+#else
        if (!ubi->scrub.rb_node) {
+#endif
                /*
                 * Now pick the least worn-out used physical eraseblock and a
                 * highly worn-out free physical eraseblock. If the erase
                 * counters differ much enough, start wear-leveling.
                 */
-               e1 = rb_entry(rb_first(&ubi->used), struct ubi_wl_entry, rb);
-               e2 = find_wl_entry(&ubi->free, WL_FREE_MAX_DIFF);
+               e1 = rb_entry(rb_first(&ubi->used), struct ubi_wl_entry, u.rb);
+               e2 = get_peb_for_wl(ubi);
+               if (!e2)
+                       goto out_cancel;
 
                if (!(e2->ec - e1->ec >= UBI_WL_THRESHOLD)) {
                        dbg_wl("no WL needed: min used EC %d, max free EC %d",
                               e1->ec, e2->ec);
+
+                       /* Give the unused PEB back */
+                       wl_tree_add(e2, &ubi->free);
+                       ubi->free_count++;
                        goto out_cancel;
                }
-               paranoid_check_in_wl_tree(e1, &ubi->used);
-               rb_erase(&e1->rb, &ubi->used);
+               self_check_in_wl_tree(ubi, e1, &ubi->used);
+               rb_erase(&e1->u.rb, &ubi->used);
                dbg_wl("move PEB %d EC %d to PEB %d EC %d",
                       e1->pnum, e1->ec, e2->pnum, e2->ec);
        } else {
                /* Perform scrubbing */
                scrubbing = 1;
-               e1 = rb_entry(rb_first(&ubi->scrub), struct ubi_wl_entry, rb);
-               e2 = find_wl_entry(&ubi->free, WL_FREE_MAX_DIFF);
-               paranoid_check_in_wl_tree(e1, &ubi->scrub);
-               rb_erase(&e1->rb, &ubi->scrub);
+               e1 = rb_entry(rb_first(&ubi->scrub), struct ubi_wl_entry, u.rb);
+               e2 = get_peb_for_wl(ubi);
+               if (!e2)
+                       goto out_cancel;
+
+               self_check_in_wl_tree(ubi, e1, &ubi->scrub);
+               rb_erase(&e1->u.rb, &ubi->scrub);
                dbg_wl("scrub PEB %d to PEB %d", e1->pnum, e2->pnum);
        }
 
-       paranoid_check_in_wl_tree(e2, &ubi->free);
-       rb_erase(&e2->rb, &ubi->free);
        ubi->move_from = e1;
        ubi->move_to = e2;
        spin_unlock(&ubi->wl_lock);
@@ -829,81 +1119,127 @@ static int wear_leveling_worker(struct ubi_device *ubi, struct ubi_work *wrk,
 
        err = ubi_io_read_vid_hdr(ubi, e1->pnum, vid_hdr, 0);
        if (err && err != UBI_IO_BITFLIPS) {
-               if (err == UBI_IO_PEB_FREE) {
+               if (err == UBI_IO_FF) {
                        /*
                         * 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;
+               } else if (err == UBI_IO_FF_BITFLIPS) {
+                       /*
+                        * The same situation as %UBI_IO_FF, but bit-flips were
+                        * detected. It is better to schedule this PEB for
+                        * scrubbing.
+                        */
+                       dbg_wl("PEB %d has no VID header but has bit-flips",
+                              e1->pnum);
+                       scrubbing = 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 < 0)
-                       goto out_error;
-               if (err == 1)
+               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 == MOVE_RETRY) {
+                       scrubbing = 1;
+                       goto out_not_moved;
+               }
+               if (err == MOVE_TARGET_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;
+               }
 
-               /*
-                * For some reason the LEB was not moved - it might be because
-                * the volume is being deleted. We should prevent this PEB from
-                * being selected for wear-levelling movement for some "time",
-                * so put it to the protection tree.
-                */
+               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;
+               }
 
-               dbg_wl("cancelled moving PEB %d", e1->pnum);
-               pe = kmalloc(sizeof(struct ubi_wl_prot_entry), GFP_NOFS);
-               if (!pe) {
-                       err = -ENOMEM;
+               if (err < 0)
                        goto out_error;
-               }
 
-               protect = 1;
+               ubi_assert(0);
        }
 
+       /* The PEB has been successfully moved */
+       if (scrubbing)
+               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 (protect)
-               prot_tree_add(ubi, e1, pe, protect);
-       if (!ubi->move_to_put)
+       if (!ubi->move_to_put) {
                wl_tree_add(e2, &ubi->used);
-       else
-               put = 1;
+               e2 = NULL;
+       }
        ubi->move_from = ubi->move_to = NULL;
        ubi->move_to_put = ubi->wl_scheduled = 0;
        spin_unlock(&ubi->wl_lock);
 
-       if (put) {
+       err = do_sync_erase(ubi, e1, vol_id, lnum, 0);
+       if (err) {
+               kmem_cache_free(ubi_wl_entry_slab, e1);
+               if (e2)
+                       kmem_cache_free(ubi_wl_entry_slab, e2);
+               goto out_ro;
+       }
+
+       if (e2) {
                /*
                 * Well, the target PEB was put meanwhile, schedule it for
                 * erasure.
                 */
-               dbg_wl("PEB %d was put meanwhile, erase", e2->pnum);
-               err = schedule_erase(ubi, e2, 0);
-               if (err)
-                       goto out_error;
-       }
-
-       if (!protect) {
-               err = schedule_erase(ubi, e1, 0);
-               if (err)
-                       goto out_error;
+               dbg_wl("PEB %d (LEB %d:%d) was put meanwhile, erase",
+                      e2->pnum, vol_id, lnum);
+               err = do_sync_erase(ubi, e2, vol_id, lnum, 0);
+               if (err) {
+                       kmem_cache_free(ubi_wl_entry_slab, e2);
+                       goto out_ro;
+               }
        }
 
-
        dbg_wl("done");
        mutex_unlock(&ubi->move_mutex);
        return 0;
@@ -911,42 +1247,60 @@ static int wear_leveling_worker(struct ubi_device *ubi, struct ubi_work *wrk,
        /*
         * For some reasons the LEB was not moved, might be an error, might be
         * something else. @e1 was not changed, so return it back. @e2 might
-        * be changed, schedule it for erasure.
+        * have been changed, schedule it for erasure.
         */
 out_not_moved:
-       ubi_free_vid_hdr(ubi, vid_hdr);
+       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);
+       ubi_assert(!ubi->move_to_put);
        ubi->move_from = ubi->move_to = NULL;
-       ubi->move_to_put = ubi->wl_scheduled = 0;
+       ubi->wl_scheduled = 0;
        spin_unlock(&ubi->wl_lock);
 
-       err = schedule_erase(ubi, e2, 0);
-       if (err)
-               goto out_error;
-
+       ubi_free_vid_hdr(ubi, vid_hdr);
+       err = do_sync_erase(ubi, e2, vol_id, lnum, torture);
+       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);
 
+       ubi_free_vid_hdr(ubi, vid_hdr);
        kmem_cache_free(ubi_wl_entry_slab, e1);
        kmem_cache_free(ubi_wl_entry_slab, e2);
-       ubi_ro_mode(ubi);
 
+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;
@@ -959,12 +1313,13 @@ out_cancel:
 /**
  * ensure_wear_leveling - schedule wear-leveling if it is needed.
  * @ubi: UBI device description object
+ * @nested: set to non-zero if this function is called from UBI worker
  *
  * This function checks if it is time to start wear-leveling and schedules it
  * if yes. This function returns zero in case of success and a negative error
  * code in case of failure.
  */
-static int ensure_wear_leveling(struct ubi_device *ubi)
+static int ensure_wear_leveling(struct ubi_device *ubi, int nested)
 {
        int err = 0;
        struct ubi_wl_entry *e1;
@@ -988,11 +1343,11 @@ static int ensure_wear_leveling(struct ubi_device *ubi)
                /*
                 * We schedule wear-leveling only if the difference between the
                 * lowest erase counter of used physical eraseblocks and a high
-                * erase counter of free physical eraseblocks is greater then
+                * erase counter of free physical eraseblocks is greater than
                 * %UBI_WL_THRESHOLD.
                 */
-               e1 = rb_entry(rb_first(&ubi->used), struct ubi_wl_entry, rb);
-               e2 = find_wl_entry(&ubi->free, WL_FREE_MAX_DIFF);
+               e1 = rb_entry(rb_first(&ubi->used), struct ubi_wl_entry, u.rb);
+               e2 = find_wl_entry(ubi, &ubi->free, WL_FREE_MAX_DIFF);
 
                if (!(e2->ec - e1->ec >= UBI_WL_THRESHOLD))
                        goto out_unlock;
@@ -1009,8 +1364,12 @@ static int ensure_wear_leveling(struct ubi_device *ubi)
                goto out_cancel;
        }
 
+       wrk->anchor = 0;
        wrk->func = &wear_leveling_worker;
-       schedule_ubi_work(ubi, wrk);
+       if (nested)
+               __schedule_ubi_work(ubi, wrk);
+       else
+               schedule_ubi_work(ubi, wrk);
        return err;
 
 out_cancel:
@@ -1021,6 +1380,38 @@ out_unlock:
        return err;
 }
 
+#ifdef CONFIG_MTD_UBI_FASTMAP
+/**
+ * ubi_ensure_anchor_pebs - schedule wear-leveling to produce an anchor PEB.
+ * @ubi: UBI device description object
+ */
+int ubi_ensure_anchor_pebs(struct ubi_device *ubi)
+{
+       struct ubi_work *wrk;
+
+       spin_lock(&ubi->wl_lock);
+       if (ubi->wl_scheduled) {
+               spin_unlock(&ubi->wl_lock);
+               return 0;
+       }
+       ubi->wl_scheduled = 1;
+       spin_unlock(&ubi->wl_lock);
+
+       wrk = kmalloc(sizeof(struct ubi_work), GFP_NOFS);
+       if (!wrk) {
+               spin_lock(&ubi->wl_lock);
+               ubi->wl_scheduled = 0;
+               spin_unlock(&ubi->wl_lock);
+               return -ENOMEM;
+       }
+
+       wrk->anchor = 1;
+       wrk->func = &wear_leveling_worker;
+       schedule_ubi_work(ubi, wrk);
+       return 0;
+}
+#endif
+
 /**
  * erase_worker - physical eraseblock erase worker function.
  * @ubi: UBI device description object
@@ -1036,7 +1427,10 @@ static int erase_worker(struct ubi_device *ubi, struct ubi_work *wl_wrk,
                        int cancel)
 {
        struct ubi_wl_entry *e = wl_wrk->e;
-       int pnum = e->pnum, err, need;
+       int pnum = e->pnum;
+       int vol_id = wl_wrk->vol_id;
+       int lnum = wl_wrk->lnum;
+       int err, available_consumed = 0;
 
        if (cancel) {
                dbg_wl("cancel erasure of PEB %d EC %d", pnum, e->ec);
@@ -1045,7 +1439,10 @@ static int erase_worker(struct ubi_device *ubi, struct ubi_work *wl_wrk,
                return 0;
        }
 
-       dbg_wl("erase PEB %d EC %d", pnum, e->ec);
+       dbg_wl("erase PEB %d EC %d LEB %d:%d",
+              pnum, e->ec, wl_wrk->vol_id, wl_wrk->lnum);
+
+       ubi_assert(!ubi_is_fm_block(ubi, e->pnum));
 
        err = sync_erase(ubi, e, wl_wrk->torture);
        if (!err) {
@@ -1053,44 +1450,45 @@ static int erase_worker(struct ubi_device *ubi, struct ubi_work *wl_wrk,
                kfree(wl_wrk);
 
                spin_lock(&ubi->wl_lock);
-               ubi->abs_ec += 1;
                wl_tree_add(e, &ubi->free);
+               ubi->free_count++;
                spin_unlock(&ubi->wl_lock);
 
                /*
-                * One more erase operation has happened, take care about protected
-                * physical eraseblocks.
+                * One more erase operation has happened, take care about
+                * protected physical eraseblocks.
                 */
-               check_protection_over(ubi);
+               serve_prot_queue(ubi);
 
                /* And take care about wear-leveling */
-               err = ensure_wear_leveling(ubi);
+               err = ensure_wear_leveling(ubi, 1);
                return err;
        }
 
        ubi_err("failed to erase PEB %d, error %d", pnum, err);
        kfree(wl_wrk);
-       kmem_cache_free(ubi_wl_entry_slab, e);
 
        if (err == -EINTR || err == -ENOMEM || err == -EAGAIN ||
            err == -EBUSY) {
                int err1;
 
                /* Re-schedule the LEB for erasure */
-               err1 = schedule_erase(ubi, e, 0);
+               err1 = schedule_erase(ubi, e, vol_id, lnum, 0);
                if (err1) {
                        err = err1;
                        goto out_ro;
                }
                return err;
-       } else if (err != -EIO) {
+       }
+
+       kmem_cache_free(ubi_wl_entry_slab, e);
+       if (err != -EIO)
                /*
                 * 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;
-       }
 
        /* It is %-EIO, the PEB went bad */
 
@@ -1100,48 +1498,62 @@ static int erase_worker(struct ubi_device *ubi, struct ubi_work *wl_wrk,
        }
 
        spin_lock(&ubi->volumes_lock);
-       need = ubi->beb_rsvd_level - ubi->beb_rsvd_pebs + 1;
-       if (need > 0) {
-               need = ubi->avail_pebs >= need ? need : ubi->avail_pebs;
-               ubi->avail_pebs -= need;
-               ubi->rsvd_pebs += need;
-               ubi->beb_rsvd_pebs += need;
-               if (need > 0)
-                       ubi_msg("reserve more %d PEBs", need);
-       }
-
        if (ubi->beb_rsvd_pebs == 0) {
-               spin_unlock(&ubi->volumes_lock);
-               ubi_err("no reserved physical eraseblocks");
-               goto out_ro;
+               if (ubi->avail_pebs == 0) {
+                       spin_unlock(&ubi->volumes_lock);
+                       ubi_err("no reserved/available physical eraseblocks");
+                       goto out_ro;
+               }
+               ubi->avail_pebs -= 1;
+               available_consumed = 1;
        }
-
        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;
 
        spin_lock(&ubi->volumes_lock);
-       ubi->beb_rsvd_pebs -= 1;
+       if (ubi->beb_rsvd_pebs > 0) {
+               if (available_consumed) {
+                       /*
+                        * The amount of reserved PEBs increased since we last
+                        * checked.
+                        */
+                       ubi->avail_pebs += 1;
+                       available_consumed = 0;
+               }
+               ubi->beb_rsvd_pebs -= 1;
+       }
        ubi->bad_peb_count += 1;
        ubi->good_peb_count -= 1;
        ubi_calculate_reserved(ubi);
-       if (ubi->beb_rsvd_pebs == 0)
-               ubi_warn("last PEB from the reserved pool was used");
+       if (available_consumed)
+               ubi_warn("no PEBs in the reserved pool, used an available PEB");
+       else if (ubi->beb_rsvd_pebs)
+               ubi_msg("%d PEBs left in the reserve", ubi->beb_rsvd_pebs);
+       else
+               ubi_warn("last PEB from the reserve was used");
        spin_unlock(&ubi->volumes_lock);
 
        return err;
 
 out_ro:
+       if (available_consumed) {
+               spin_lock(&ubi->volumes_lock);
+               ubi->avail_pebs += 1;
+               spin_unlock(&ubi->volumes_lock);
+       }
        ubi_ro_mode(ubi);
        return err;
 }
 
 /**
- * ubi_wl_put_peb - return a physical eraseblock to the wear-leveling unit.
+ * ubi_wl_put_peb - return a PEB to the wear-leveling sub-system.
  * @ubi: UBI device description object
+ * @vol_id: the volume ID that last used this PEB
+ * @lnum: the last used logical eraseblock number for the PEB
  * @pnum: physical eraseblock to return
  * @torture: if this physical eraseblock has to be tortured
  *
@@ -1150,7 +1562,8 @@ out_ro:
  * occurred to this @pnum and it has to be tested. This function returns zero
  * in case of success, and a negative error code in case of failure.
  */
-int ubi_wl_put_peb(struct ubi_device *ubi, int pnum, int torture)
+int ubi_wl_put_peb(struct ubi_device *ubi, int vol_id, int lnum,
+                  int pnum, int torture)
 {
        int err;
        struct ubi_wl_entry *e;
@@ -1179,11 +1592,11 @@ retry:
                /*
                 * User is putting the physical eraseblock which was selected
                 * as the target the data is moved to. It may happen if the EBA
-                * unit already re-mapped the LEB in 'ubi_eba_copy_leb()' but
-                * the WL unit has not put the PEB to the "used" tree yet, but
-                * it is about to do this. So we just set a flag which will
-                * tell the WL worker that the PEB is not needed anymore and
-                * should be scheduled for erasure.
+                * sub-system already re-mapped the LEB in 'ubi_eba_copy_leb()'
+                * but the WL sub-system has not put the PEB to the "used" tree
+                * yet, but it is about to do this. So we just set a flag which
+                * will tell the WL worker that the PEB is not needed anymore
+                * and should be scheduled for erasure.
                 */
                dbg_wl("PEB %d is the target of data moving", pnum);
                ubi_assert(!ubi->move_to_put);
@@ -1192,13 +1605,20 @@ retry:
                return 0;
        } else {
                if (in_wl_tree(e, &ubi->used)) {
-                       paranoid_check_in_wl_tree(e, &ubi->used);
-                       rb_erase(&e->rb, &ubi->used);
+                       self_check_in_wl_tree(ubi, e, &ubi->used);
+                       rb_erase(&e->u.rb, &ubi->used);
                } else if (in_wl_tree(e, &ubi->scrub)) {
-                       paranoid_check_in_wl_tree(e, &ubi->scrub);
-                       rb_erase(&e->rb, &ubi->scrub);
+                       self_check_in_wl_tree(ubi, e, &ubi->scrub);
+                       rb_erase(&e->u.rb, &ubi->scrub);
+               } else if (in_wl_tree(e, &ubi->erroneous)) {
+                       self_check_in_wl_tree(ubi, 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_tree_del(ubi, e->pnum);
+                       err = prot_queue_del(ubi, e->pnum);
                        if (err) {
                                ubi_err("PEB %d not found", pnum);
                                ubi_ro_mode(ubi);
@@ -1209,7 +1629,7 @@ retry:
        }
        spin_unlock(&ubi->wl_lock);
 
-       err = schedule_erase(ubi, e, torture);
+       err = schedule_erase(ubi, e, vol_id, lnum, torture);
        if (err) {
                spin_lock(&ubi->wl_lock);
                wl_tree_add(e, &ubi->used);
@@ -1238,7 +1658,8 @@ int ubi_wl_scrub_peb(struct ubi_device *ubi, int pnum)
 retry:
        spin_lock(&ubi->wl_lock);
        e = ubi->lookuptbl[pnum];
-       if (e == ubi->move_from || in_wl_tree(e, &ubi->scrub)) {
+       if (e == ubi->move_from || in_wl_tree(e, &ubi->scrub) ||
+                                  in_wl_tree(e, &ubi->erroneous)) {
                spin_unlock(&ubi->wl_lock);
                return 0;
        }
@@ -1257,12 +1678,12 @@ retry:
        }
 
        if (in_wl_tree(e, &ubi->used)) {
-               paranoid_check_in_wl_tree(e, &ubi->used);
-               rb_erase(&e->rb, &ubi->used);
+               self_check_in_wl_tree(ubi, e, &ubi->used);
+               rb_erase(&e->u.rb, &ubi->used);
        } else {
                int err;
 
-               err = prot_tree_del(ubi, e->pnum);
+               err = prot_queue_del(ubi, e->pnum);
                if (err) {
                        ubi_err("PEB %d not found", pnum);
                        ubi_ro_mode(ubi);
@@ -1278,29 +1699,60 @@ retry:
         * Technically scrubbing is the same as wear-leveling, so it is done
         * by the WL worker.
         */
-       return ensure_wear_leveling(ubi);
+       return ensure_wear_leveling(ubi, 0);
 }
 
 /**
  * ubi_wl_flush - flush all pending works.
  * @ubi: UBI device description object
+ * @vol_id: the volume id to flush for
+ * @lnum: the logical eraseblock number to flush for
  *
- * This function returns zero in case of success and a negative error code in
- * case of failure.
+ * This function executes all pending works for a particular volume id /
+ * logical eraseblock number pair. If either value is set to %UBI_ALL, then it
+ * acts as a wildcard for all of the corresponding volume numbers or logical
+ * eraseblock numbers. It returns zero in case of success and a negative error
+ * code in case of failure.
  */
-int ubi_wl_flush(struct ubi_device *ubi)
+int ubi_wl_flush(struct ubi_device *ubi, int vol_id, int lnum)
 {
-       int err;
+       int err = 0;
+       int found = 1;
 
        /*
-        * Erase while the pending works queue is not empty, but not more then
+        * Erase while the pending works queue is not empty, but not more than
         * the number of currently pending works.
         */
-       dbg_wl("flush (%d pending works)", ubi->works_count);
-       while (ubi->works_count) {
-               err = do_work(ubi);
-               if (err)
-                       return err;
+       dbg_wl("flush pending work for LEB %d:%d (%d pending works)",
+              vol_id, lnum, ubi->works_count);
+
+       while (found) {
+               struct ubi_work *wrk;
+               found = 0;
+
+               down_read(&ubi->work_sem);
+               spin_lock(&ubi->wl_lock);
+               list_for_each_entry(wrk, &ubi->works, list) {
+                       if ((vol_id == UBI_ALL || wrk->vol_id == vol_id) &&
+                           (lnum == UBI_ALL || wrk->lnum == lnum)) {
+                               list_del(&wrk->list);
+                               ubi->works_count -= 1;
+                               ubi_assert(ubi->works_count >= 0);
+                               spin_unlock(&ubi->wl_lock);
+
+                               err = wrk->func(ubi, wrk, 0);
+                               if (err) {
+                                       up_read(&ubi->work_sem);
+                                       return err;
+                               }
+
+                               spin_lock(&ubi->wl_lock);
+                               found = 1;
+                               break;
+                       }
+               }
+               spin_unlock(&ubi->wl_lock);
+               up_read(&ubi->work_sem);
        }
 
        /*
@@ -1310,18 +1762,7 @@ int ubi_wl_flush(struct ubi_device *ubi)
        down_write(&ubi->work_sem);
        up_write(&ubi->work_sem);
 
-       /*
-        * And in case last was the WL worker and it cancelled the LEB
-        * movement, flush again.
-        */
-       while (ubi->works_count) {
-               dbg_wl("flush more (%d pending works)", ubi->works_count);
-               err = do_work(ubi);
-               if (err)
-                       return err;
-       }
-
-       return 0;
+       return err;
 }
 
 /**
@@ -1340,11 +1781,11 @@ static void tree_destroy(struct rb_root *root)
                else if (rb->rb_right)
                        rb = rb->rb_right;
                else {
-                       e = rb_entry(rb, struct ubi_wl_entry, rb);
+                       e = rb_entry(rb, struct ubi_wl_entry, u.rb);
 
                        rb = rb_parent(rb);
                        if (rb) {
-                               if (rb->rb_left == &e->rb)
+                               if (rb->rb_left == &e->u.rb)
                                        rb->rb_left = NULL;
                                else
                                        rb->rb_right = NULL;
@@ -1379,7 +1820,7 @@ int ubi_thread(void *u)
 
                spin_lock(&ubi->wl_lock);
                if (list_empty(&ubi->works) || ubi->ro_mode ||
-                              !ubi->thread_enabled) {
+                   !ubi->thread_enabled || ubi_dbg_is_bgt_disabled(ubi)) {
                        set_current_state(TASK_INTERRUPTIBLE);
                        spin_unlock(&ubi->wl_lock);
                        schedule();
@@ -1399,7 +1840,8 @@ int ubi_thread(void *u)
                                ubi_msg("%s: %d consecutive failures",
                                        ubi->bgt_name, WL_MAX_FAILURES);
                                ubi_ro_mode(ubi);
-                               break;
+                               ubi->thread_enabled = 0;
+                               continue;
                        }
                } else
                        failures = 0;
@@ -1429,30 +1871,32 @@ static void cancel_pending(struct ubi_device *ubi)
 }
 
 /**
- * ubi_wl_init_scan - initialize the wear-leveling unit using scanning
- * information.
+ * ubi_wl_init - initialize the WL sub-system using attaching information.
  * @ubi: UBI device description object
- * @si: scanning information
+ * @ai: attaching information
  *
  * This function returns zero in case of success, and a negative error code in
  * case of failure.
  */
-int ubi_wl_init_scan(struct ubi_device *ubi, struct ubi_scan_info *si)
+int ubi_wl_init(struct ubi_device *ubi, struct ubi_attach_info *ai)
 {
-       int err;
+       int err, i, reserved_pebs, found_pebs = 0;
        struct rb_node *rb1, *rb2;
-       struct ubi_scan_volume *sv;
-       struct ubi_scan_leb *seb, *tmp;
+       struct ubi_ainf_volume *av;
+       struct ubi_ainf_peb *aeb, *tmp;
        struct ubi_wl_entry *e;
 
-
-       ubi->used = ubi->free = ubi->scrub = RB_ROOT;
-       ubi->prot.pnum = ubi->prot.aec = 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);
-       ubi->max_ec = si->max_ec;
+       ubi->max_ec = ai->max_ec;
        INIT_LIST_HEAD(&ubi->works);
+#ifndef __UBOOT__
+#ifdef CONFIG_MTD_UBI_FASTMAP
+       INIT_WORK(&ubi->fm_work, update_fastmap_work_fn);
+#endif
+#endif
 
        sprintf(ubi->bgt_name, UBI_BGT_NAME_PATTERN, ubi->ubi_num);
 
@@ -1461,64 +1905,63 @@ int ubi_wl_init_scan(struct ubi_device *ubi, struct ubi_scan_info *si)
        if (!ubi->lookuptbl)
                return err;
 
-       list_for_each_entry_safe(seb, tmp, &si->erase, u.list) {
+       for (i = 0; i < UBI_PROT_QUEUE_LEN; i++)
+               INIT_LIST_HEAD(&ubi->pq[i]);
+       ubi->pq_head = 0;
+
+       list_for_each_entry_safe(aeb, tmp, &ai->erase, u.list) {
                cond_resched();
 
                e = kmem_cache_alloc(ubi_wl_entry_slab, GFP_KERNEL);
                if (!e)
                        goto out_free;
 
-               e->pnum = seb->pnum;
-               e->ec = seb->ec;
+               e->pnum = aeb->pnum;
+               e->ec = aeb->ec;
+               ubi_assert(!ubi_is_fm_block(ubi, e->pnum));
                ubi->lookuptbl[e->pnum] = e;
-               if (schedule_erase(ubi, e, 0)) {
+               if (schedule_erase(ubi, e, aeb->vol_id, aeb->lnum, 0)) {
                        kmem_cache_free(ubi_wl_entry_slab, e);
                        goto out_free;
                }
+
+               found_pebs++;
        }
 
-       list_for_each_entry(seb, &si->free, u.list) {
+       ubi->free_count = 0;
+       list_for_each_entry(aeb, &ai->free, u.list) {
                cond_resched();
 
                e = kmem_cache_alloc(ubi_wl_entry_slab, GFP_KERNEL);
                if (!e)
                        goto out_free;
 
-               e->pnum = seb->pnum;
-               e->ec = seb->ec;
+               e->pnum = aeb->pnum;
+               e->ec = aeb->ec;
                ubi_assert(e->ec >= 0);
-               wl_tree_add(e, &ubi->free);
-               ubi->lookuptbl[e->pnum] = e;
-       }
-
-       list_for_each_entry(seb, &si->corr, u.list) {
-               cond_resched();
+               ubi_assert(!ubi_is_fm_block(ubi, e->pnum));
 
-               e = kmem_cache_alloc(ubi_wl_entry_slab, GFP_KERNEL);
-               if (!e)
-                       goto out_free;
+               wl_tree_add(e, &ubi->free);
+               ubi->free_count++;
 
-               e->pnum = seb->pnum;
-               e->ec = seb->ec;
                ubi->lookuptbl[e->pnum] = e;
-               if (schedule_erase(ubi, e, 0)) {
-                       kmem_cache_free(ubi_wl_entry_slab, e);
-                       goto out_free;
-               }
+
+               found_pebs++;
        }
 
-       ubi_rb_for_each_entry(rb1, sv, &si->volumes, rb) {
-               ubi_rb_for_each_entry(rb2, seb, &sv->root, u.rb) {
+       ubi_rb_for_each_entry(rb1, av, &ai->volumes, rb) {
+               ubi_rb_for_each_entry(rb2, aeb, &av->root, u.rb) {
                        cond_resched();
 
                        e = kmem_cache_alloc(ubi_wl_entry_slab, GFP_KERNEL);
                        if (!e)
                                goto out_free;
 
-                       e->pnum = seb->pnum;
-                       e->ec = seb->ec;
+                       e->pnum = aeb->pnum;
+                       e->ec = aeb->ec;
                        ubi->lookuptbl[e->pnum] = e;
-                       if (!seb->scrub) {
+
+                       if (!aeb->scrub) {
                                dbg_wl("add PEB %d EC %d to the used tree",
                                       e->pnum, e->ec);
                                wl_tree_add(e, &ubi->used);
@@ -1527,19 +1970,38 @@ int ubi_wl_init_scan(struct ubi_device *ubi, struct ubi_scan_info *si)
                                       e->pnum, e->ec);
                                wl_tree_add(e, &ubi->scrub);
                        }
+
+                       found_pebs++;
                }
        }
 
-       if (ubi->avail_pebs < WL_RESERVED_PEBS) {
+       dbg_wl("found %i PEBs", found_pebs);
+
+       if (ubi->fm)
+               ubi_assert(ubi->good_peb_count == \
+                          found_pebs + ubi->fm->used_blocks);
+       else
+               ubi_assert(ubi->good_peb_count == found_pebs);
+
+       reserved_pebs = WL_RESERVED_PEBS;
+#ifdef CONFIG_MTD_UBI_FASTMAP
+       /* Reserve enough LEBs to store two fastmaps. */
+       reserved_pebs += (ubi->fm_size / ubi->leb_size) * 2;
+#endif
+
+       if (ubi->avail_pebs < reserved_pebs) {
                ubi_err("no enough physical eraseblocks (%d, need %d)",
-                       ubi->avail_pebs, WL_RESERVED_PEBS);
+                       ubi->avail_pebs, reserved_pebs);
+               if (ubi->corr_peb_count)
+                       ubi_err("%d PEBs are corrupted and not used",
+                               ubi->corr_peb_count);
                goto out_free;
        }
-       ubi->avail_pebs -= WL_RESERVED_PEBS;
-       ubi->rsvd_pebs += WL_RESERVED_PEBS;
+       ubi->avail_pebs -= reserved_pebs;
+       ubi->rsvd_pebs += reserved_pebs;
 
        /* Schedule wear-leveling if needed */
-       err = ensure_wear_leveling(ubi);
+       err = ensure_wear_leveling(ubi, 0);
        if (err)
                goto out_free;
 
@@ -1555,72 +2017,57 @@ out_free:
 }
 
 /**
- * protection_trees_destroy - destroy the protection RB-trees.
+ * protection_queue_destroy - destroy the protection queue.
  * @ubi: UBI device description object
  */
-static void protection_trees_destroy(struct ubi_device *ubi)
+static void protection_queue_destroy(struct ubi_device *ubi)
 {
-       struct rb_node *rb;
-       struct ubi_wl_prot_entry *pe;
-
-       rb = ubi->prot.aec.rb_node;
-       while (rb) {
-               if (rb->rb_left)
-                       rb = rb->rb_left;
-               else if (rb->rb_right)
-                       rb = rb->rb_right;
-               else {
-                       pe = rb_entry(rb, struct ubi_wl_prot_entry, rb_aec);
-
-                       rb = rb_parent(rb);
-                       if (rb) {
-                               if (rb->rb_left == &pe->rb_aec)
-                                       rb->rb_left = NULL;
-                               else
-                                       rb->rb_right = NULL;
-                       }
+       int i;
+       struct ubi_wl_entry *e, *tmp;
 
-                       kmem_cache_free(ubi_wl_entry_slab, pe->e);
-                       kfree(pe);
+       for (i = 0; i < UBI_PROT_QUEUE_LEN; ++i) {
+               list_for_each_entry_safe(e, tmp, &ubi->pq[i], u.list) {
+                       list_del(&e->u.list);
+                       kmem_cache_free(ubi_wl_entry_slab, e);
                }
        }
 }
 
 /**
- * ubi_wl_close - close the wear-leveling unit.
+ * ubi_wl_close - close the wear-leveling sub-system.
  * @ubi: UBI device description object
  */
 void ubi_wl_close(struct ubi_device *ubi)
 {
-       dbg_wl("close the UBI wear-leveling unit");
-
+       dbg_wl("close the WL sub-system");
        cancel_pending(ubi);
-       protection_trees_destroy(ubi);
+       protection_queue_destroy(ubi);
        tree_destroy(&ubi->used);
+       tree_destroy(&ubi->erroneous);
        tree_destroy(&ubi->free);
        tree_destroy(&ubi->scrub);
        kfree(ubi->lookuptbl);
 }
 
-#ifdef CONFIG_MTD_UBI_DEBUG_PARANOID
-
 /**
- * paranoid_check_ec - make sure that the erase counter of a physical eraseblock
- * is correct.
+ * self_check_ec - make sure that the erase counter of a PEB is correct.
  * @ubi: UBI device description object
  * @pnum: the physical eraseblock number to check
  * @ec: the erase counter to check
  *
  * This function returns zero if the erase counter of physical eraseblock @pnum
- * is equivalent to @ec, %1 if not, and a negative error code if an error
+ * is equivalent to @ec, and a negative error code if not or if an error
  * occurred.
  */
-static int paranoid_check_ec(struct ubi_device *ubi, int pnum, int ec)
+static int self_check_ec(struct ubi_device *ubi, int pnum, int ec)
 {
        int err;
        long long read_ec;
        struct ubi_ec_hdr *ec_hdr;
 
+       if (!ubi_dbg_chk_gen(ubi))
+               return 0;
+
        ec_hdr = kzalloc(ubi->ec_hdr_alsize, GFP_NOFS);
        if (!ec_hdr)
                return -ENOMEM;
@@ -1633,10 +2080,10 @@ static int paranoid_check_ec(struct ubi_device *ubi, int pnum, int ec)
        }
 
        read_ec = be64_to_cpu(ec_hdr->ec);
-       if (ec != read_ec) {
-               ubi_err("paranoid check failed for PEB %d", pnum);
+       if (ec != read_ec && read_ec - ec > 1) {
+               ubi_err("self-check failed for PEB %d", pnum);
                ubi_err("read EC is %lld, should be %d", read_ec, ec);
-               ubi_dbg_dump_stack();
+               dump_stack();
                err = 1;
        } else
                err = 0;
@@ -1647,24 +2094,53 @@ out_free:
 }
 
 /**
- * paranoid_check_in_wl_tree - make sure that a wear-leveling entry is present
- * in a WL RB-tree.
+ * self_check_in_wl_tree - check that wear-leveling entry is in WL RB-tree.
+ * @ubi: UBI device description object
  * @e: the wear-leveling entry to check
  * @root: the root of the tree
  *
- * This function returns zero if @e is in the @root RB-tree and %1 if it
+ * This function returns zero if @e is in the @root RB-tree and %-EINVAL if it
  * is not.
  */
-static int paranoid_check_in_wl_tree(struct ubi_wl_entry *e,
-                                    struct rb_root *root)
+static int self_check_in_wl_tree(const struct ubi_device *ubi,
+                                struct ubi_wl_entry *e, struct rb_root *root)
 {
+       if (!ubi_dbg_chk_gen(ubi))
+               return 0;
+
        if (in_wl_tree(e, root))
                return 0;
 
-       ubi_err("paranoid check failed for PEB %d, EC %d, RB-tree %p ",
+       ubi_err("self-check failed for PEB %d, EC %d, RB-tree %p ",
                e->pnum, e->ec, root);
-       ubi_dbg_dump_stack();
-       return 1;
+       dump_stack();
+       return -EINVAL;
 }
 
-#endif /* CONFIG_MTD_UBI_DEBUG_PARANOID */
+/**
+ * self_check_in_pq - check if wear-leveling entry is in the protection
+ *                        queue.
+ * @ubi: UBI device description object
+ * @e: the wear-leveling entry to check
+ *
+ * This function returns zero if @e is in @ubi->pq and %-EINVAL if it is not.
+ */
+static int self_check_in_pq(const struct ubi_device *ubi,
+                           struct ubi_wl_entry *e)
+{
+       struct ubi_wl_entry *p;
+       int i;
+
+       if (!ubi_dbg_chk_gen(ubi))
+               return 0;
+
+       for (i = 0; i < UBI_PROT_QUEUE_LEN; ++i)
+               list_for_each_entry(p, &ubi->pq[i], u.list)
+                       if (p == e)
+                               return 0;
+
+       ubi_err("self-check failed for PEB %d, EC %d, Protect queue",
+               e->pnum, e->ec);
+       dump_stack();
+       return -EINVAL;
+}