mtd, ubi, ubifs: resync with Linux-3.14

resync ubi subsystem with linux:

commit 455c6fdbd219161bd09b1165f11699d6d73de11c
Author: Linus Torvalds <torvalds@linux-foundation.org>
Date:   Sun Mar 30 20:40:15 2014 -0700

    Linux 3.14

A nice side effect of this, is we introduce UBI Fastmap support
to U-Boot.

Signed-off-by: Heiko Schocher <hs@denx.de>
Signed-off-by: Tom Rini <trini@ti.com>
Cc: Marek Vasut <marex@denx.de>
Cc: Sergey Lapin <slapin@ossfans.org>
Cc: Scott Wood <scottwood@freescale.com>
Cc: Joerg Krause <jkrause@posteo.de>

1 files changed, 1021 insertions, 545 deletions

diff --git a/drivers/mtd/ubi/wl.c b/drivers/mtd/ubi/wl.c
index 1eaa88b36f..2987ffc093 100644
--- a/drivers/mtd/ubi/wl.c
+++ b/drivers/mtd/ubi/wl.c
@@ -7,97 +7,117 @@
  */
 
 /*
- * 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.
  *
- * If the WL unit 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.
  *
- * 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.
+ * 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.
  *
- * 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.
+ * 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.
+ *
+ * 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.
+ *
+ * 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).
+ *
+ * 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)
@@ -108,89 +128,48 @@
  */
 #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;
+
+	if (!ubi->fm)
+		return 0;
+
+	for (i = 0; i < ubi->fm->used_blocks; i++)
+		if (ubi->fm->e[i]->pnum == pnum)
+			return 1;
 
-#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);
+	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
 
 /**
@@ -210,7 +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;
@@ -225,8 +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);
 }
 
 /**
@@ -289,18 +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;
 }
@@ -321,7 +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);
@@ -345,223 +322,401 @@ 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);
+	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);
+
+	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
 
-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);
+/**
+ * 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;
+
+	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;
 }
 
@@ -574,7 +729,8 @@ 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;
@@ -582,8 +738,8 @@ 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);
@@ -626,91 +782,124 @@ 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;
-
+#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);
 }
 
+/**
+ * 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 torture)
+			  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);
 
@@ -720,6 +909,8 @@ static int schedule_erase(struct ubi_device *ubi, struct ubi_wl_entry *e,
 
 	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);
@@ -727,6 +918,79 @@ static int schedule_erase(struct ubi_device *ubi, struct ubi_wl_entry *e,
 }
 
 /**
+ * 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
+ *
+ */
+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("sync erase of PEB %i", e->pnum);
+
+	wl_wrk = kmalloc(sizeof(struct ubi_work), GFP_NOFS);
+	if (!wl_wrk)
+		return -ENOMEM;
+
+	wl_wrk->e = e;
+	wl_wrk->vol_id = vol_id;
+	wl_wrk->lnum = lnum;
+	wl_wrk->torture = torture;
+
+	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.
  * @ubi: UBI device description object
  * @wrk: the work object
@@ -739,13 +1003,15 @@ 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;
 
@@ -775,36 +1041,61 @@ 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);
 			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);
@@ -822,81 +1113,127 @@ 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;
@@ -904,42 +1241,60 @@ 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;
@@ -952,12 +1307,13 @@ 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;
@@ -981,11 +1337,11 @@ 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;
@@ -1002,8 +1358,12 @@ 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:
@@ -1014,6 +1374,38 @@ 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
@@ -1029,7 +1421,10 @@ 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);
@@ -1038,7 +1433,10 @@ 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) {
@@ -1046,44 +1444,45 @@ 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 */
 
@@ -1093,48 +1492,62 @@ 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
  *
@@ -1143,7 +1556,8 @@ 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;
@@ -1172,11 +1586,11 @@ 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);
@@ -1185,13 +1599,20 @@ 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);
@@ -1202,7 +1623,7 @@ 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);
@@ -1231,7 +1652,8 @@ 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;
 	}
@@ -1250,12 +1672,12 @@ 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);
@@ -1271,29 +1693,60 @@ 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);
 	}
 
 	/*
@@ -1303,18 +1756,7 @@ 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;
 }
 
 /**
@@ -1333,11 +1775,11 @@ 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;
@@ -1372,7 +1814,7 @@ 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();
@@ -1392,7 +1834,8 @@ 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;
@@ -1422,30 +1865,32 @@ 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);
 
@@ -1454,64 +1899,63 @@ 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);
@@ -1520,20 +1964,38 @@ 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);
-		err = -ENOSPC;
+			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;
 
@@ -1549,72 +2011,57 @@ 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;
+	int i;
+	struct ubi_wl_entry *e, *tmp;
 
-	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;
-			}
-
-			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;
@@ -1627,10 +2074,10 @@ 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;
@@ -1641,24 +2088,53 @@ 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;
+}