Adding upstream version 5.10.209.upstream/5.10.209upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1699 insertions, 0 deletions

diff --git a/drivers/mtd/ubi/fastmap.c b/drivers/mtd/ubi/fastmap.c
new file mode 100644
index 000000000..6e95c4b14
--- /dev/null
+++ b/drivers/mtd/ubi/fastmap.c
@@ -0,0 +1,1699 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2012 Linutronix GmbH
+ * Copyright (c) 2014 sigma star gmbh
+ * Author: Richard Weinberger <richard@nod.at>
+ */
+
+#include <linux/crc32.h>
+#include <linux/bitmap.h>
+#include "ubi.h"
+
+/**
+ * init_seen - allocate memory for used for debugging.
+ * @ubi: UBI device description object
+ */
+static inline unsigned long *init_seen(struct ubi_device *ubi)
+{
+	unsigned long *ret;
+
+	if (!ubi_dbg_chk_fastmap(ubi))
+		return NULL;
+
+	ret = kcalloc(BITS_TO_LONGS(ubi->peb_count), sizeof(unsigned long),
+		      GFP_KERNEL);
+	if (!ret)
+		return ERR_PTR(-ENOMEM);
+
+	return ret;
+}
+
+/**
+ * free_seen - free the seen logic integer array.
+ * @seen: integer array of @ubi->peb_count size
+ */
+static inline void free_seen(unsigned long *seen)
+{
+	kfree(seen);
+}
+
+/**
+ * set_seen - mark a PEB as seen.
+ * @ubi: UBI device description object
+ * @pnum: The PEB to be makred as seen
+ * @seen: integer array of @ubi->peb_count size
+ */
+static inline void set_seen(struct ubi_device *ubi, int pnum, unsigned long *seen)
+{
+	if (!ubi_dbg_chk_fastmap(ubi) || !seen)
+		return;
+
+	set_bit(pnum, seen);
+}
+
+/**
+ * self_check_seen - check whether all PEB have been seen by fastmap.
+ * @ubi: UBI device description object
+ * @seen: integer array of @ubi->peb_count size
+ */
+static int self_check_seen(struct ubi_device *ubi, unsigned long *seen)
+{
+	int pnum, ret = 0;
+
+	if (!ubi_dbg_chk_fastmap(ubi) || !seen)
+		return 0;
+
+	for (pnum = 0; pnum < ubi->peb_count; pnum++) {
+		if (!test_bit(pnum, seen) && ubi->lookuptbl[pnum]) {
+			ubi_err(ubi, "self-check failed for PEB %d, fastmap didn't see it", pnum);
+			ret = -EINVAL;
+		}
+	}
+
+	return ret;
+}
+
+/**
+ * ubi_calc_fm_size - calculates the fastmap size in bytes for an UBI device.
+ * @ubi: UBI device description object
+ */
+size_t ubi_calc_fm_size(struct ubi_device *ubi)
+{
+	size_t size;
+
+	size = sizeof(struct ubi_fm_sb) +
+		sizeof(struct ubi_fm_hdr) +
+		sizeof(struct ubi_fm_scan_pool) +
+		sizeof(struct ubi_fm_scan_pool) +
+		(ubi->peb_count * sizeof(struct ubi_fm_ec)) +
+		(sizeof(struct ubi_fm_eba) +
+		(ubi->peb_count * sizeof(__be32))) +
+		sizeof(struct ubi_fm_volhdr) * UBI_MAX_VOLUMES;
+	return roundup(size, ubi->leb_size);
+}
+
+
+/**
+ * new_fm_vhdr - allocate a new volume header for fastmap usage.
+ * @ubi: UBI device description object
+ * @vol_id: the VID of the new header
+ *
+ * Returns a new struct ubi_vid_hdr on success.
+ * NULL indicates out of memory.
+ */
+static struct ubi_vid_io_buf *new_fm_vbuf(struct ubi_device *ubi, int vol_id)
+{
+	struct ubi_vid_io_buf *new;
+	struct ubi_vid_hdr *vh;
+
+	new = ubi_alloc_vid_buf(ubi, GFP_KERNEL);
+	if (!new)
+		goto out;
+
+	vh = ubi_get_vid_hdr(new);
+	vh->vol_type = UBI_VID_DYNAMIC;
+	vh->vol_id = cpu_to_be32(vol_id);
+
+	/* UBI implementations without fastmap support have to delete the
+	 * fastmap.
+	 */
+	vh->compat = UBI_COMPAT_DELETE;
+
+out:
+	return new;
+}
+
+/**
+ * add_aeb - create and add a attach erase block to a given list.
+ * @ai: UBI attach info object
+ * @list: the target list
+ * @pnum: PEB number of the new attach erase block
+ * @ec: erease counter of the new LEB
+ * @scrub: scrub this PEB after attaching
+ *
+ * Returns 0 on success, < 0 indicates an internal error.
+ */
+static int add_aeb(struct ubi_attach_info *ai, struct list_head *list,
+		   int pnum, int ec, int scrub)
+{
+	struct ubi_ainf_peb *aeb;
+
+	aeb = ubi_alloc_aeb(ai, pnum, ec);
+	if (!aeb)
+		return -ENOMEM;
+
+	aeb->lnum = -1;
+	aeb->scrub = scrub;
+	aeb->copy_flag = aeb->sqnum = 0;
+
+	ai->ec_sum += aeb->ec;
+	ai->ec_count++;
+
+	if (ai->max_ec < aeb->ec)
+		ai->max_ec = aeb->ec;
+
+	if (ai->min_ec > aeb->ec)
+		ai->min_ec = aeb->ec;
+
+	list_add_tail(&aeb->u.list, list);
+
+	return 0;
+}
+
+/**
+ * add_vol - create and add a new volume to ubi_attach_info.
+ * @ai: ubi_attach_info object
+ * @vol_id: VID of the new volume
+ * @used_ebs: number of used EBS
+ * @data_pad: data padding value of the new volume
+ * @vol_type: volume type
+ * @last_eb_bytes: number of bytes in the last LEB
+ *
+ * Returns the new struct ubi_ainf_volume on success.
+ * NULL indicates an error.
+ */
+static struct ubi_ainf_volume *add_vol(struct ubi_attach_info *ai, int vol_id,
+				       int used_ebs, int data_pad, u8 vol_type,
+				       int last_eb_bytes)
+{
+	struct ubi_ainf_volume *av;
+
+	av = ubi_add_av(ai, vol_id);
+	if (IS_ERR(av))
+		return av;
+
+	av->data_pad = data_pad;
+	av->last_data_size = last_eb_bytes;
+	av->compat = 0;
+	av->vol_type = vol_type;
+	if (av->vol_type == UBI_STATIC_VOLUME)
+		av->used_ebs = used_ebs;
+
+	dbg_bld("found volume (ID %i)", vol_id);
+	return av;
+}
+
+/**
+ * assign_aeb_to_av - assigns a SEB to a given ainf_volume and removes it
+ * from it's original list.
+ * @ai: ubi_attach_info object
+ * @aeb: the to be assigned SEB
+ * @av: target scan volume
+ */
+static void assign_aeb_to_av(struct ubi_attach_info *ai,
+			     struct ubi_ainf_peb *aeb,
+			     struct ubi_ainf_volume *av)
+{
+	struct ubi_ainf_peb *tmp_aeb;
+	struct rb_node **p = &av->root.rb_node, *parent = NULL;
+
+	while (*p) {
+		parent = *p;
+
+		tmp_aeb = rb_entry(parent, struct ubi_ainf_peb, u.rb);
+		if (aeb->lnum != tmp_aeb->lnum) {
+			if (aeb->lnum < tmp_aeb->lnum)
+				p = &(*p)->rb_left;
+			else
+				p = &(*p)->rb_right;
+
+			continue;
+		} else
+			break;
+	}
+
+	list_del(&aeb->u.list);
+	av->leb_count++;
+
+	rb_link_node(&aeb->u.rb, parent, p);
+	rb_insert_color(&aeb->u.rb, &av->root);
+}
+
+/**
+ * update_vol - inserts or updates a LEB which was found a pool.
+ * @ubi: the UBI device object
+ * @ai: attach info object
+ * @av: the volume this LEB belongs to
+ * @new_vh: the volume header derived from new_aeb
+ * @new_aeb: the AEB to be examined
+ *
+ * Returns 0 on success, < 0 indicates an internal error.
+ */
+static int update_vol(struct ubi_device *ubi, struct ubi_attach_info *ai,
+		      struct ubi_ainf_volume *av, struct ubi_vid_hdr *new_vh,
+		      struct ubi_ainf_peb *new_aeb)
+{
+	struct rb_node **p = &av->root.rb_node, *parent = NULL;
+	struct ubi_ainf_peb *aeb, *victim;
+	int cmp_res;
+
+	while (*p) {
+		parent = *p;
+		aeb = rb_entry(parent, struct ubi_ainf_peb, u.rb);
+
+		if (be32_to_cpu(new_vh->lnum) != aeb->lnum) {
+			if (be32_to_cpu(new_vh->lnum) < aeb->lnum)
+				p = &(*p)->rb_left;
+			else
+				p = &(*p)->rb_right;
+
+			continue;
+		}
+
+		/* This case can happen if the fastmap gets written
+		 * because of a volume change (creation, deletion, ..).
+		 * Then a PEB can be within the persistent EBA and the pool.
+		 */
+		if (aeb->pnum == new_aeb->pnum) {
+			ubi_assert(aeb->lnum == new_aeb->lnum);
+			ubi_free_aeb(ai, new_aeb);
+
+			return 0;
+		}
+
+		cmp_res = ubi_compare_lebs(ubi, aeb, new_aeb->pnum, new_vh);
+		if (cmp_res < 0)
+			return cmp_res;
+
+		/* new_aeb is newer */
+		if (cmp_res & 1) {
+			victim = ubi_alloc_aeb(ai, aeb->pnum, aeb->ec);
+			if (!victim)
+				return -ENOMEM;
+
+			list_add_tail(&victim->u.list, &ai->erase);
+
+			if (av->highest_lnum == be32_to_cpu(new_vh->lnum))
+				av->last_data_size =
+					be32_to_cpu(new_vh->data_size);
+
+			dbg_bld("vol %i: AEB %i's PEB %i is the newer",
+				av->vol_id, aeb->lnum, new_aeb->pnum);
+
+			aeb->ec = new_aeb->ec;
+			aeb->pnum = new_aeb->pnum;
+			aeb->copy_flag = new_vh->copy_flag;
+			aeb->scrub = new_aeb->scrub;
+			aeb->sqnum = new_aeb->sqnum;
+			ubi_free_aeb(ai, new_aeb);
+
+		/* new_aeb is older */
+		} else {
+			dbg_bld("vol %i: AEB %i's PEB %i is old, dropping it",
+				av->vol_id, aeb->lnum, new_aeb->pnum);
+			list_add_tail(&new_aeb->u.list, &ai->erase);
+		}
+
+		return 0;
+	}
+	/* This LEB is new, let's add it to the volume */
+
+	if (av->highest_lnum <= be32_to_cpu(new_vh->lnum)) {
+		av->highest_lnum = be32_to_cpu(new_vh->lnum);
+		av->last_data_size = be32_to_cpu(new_vh->data_size);
+	}
+
+	if (av->vol_type == UBI_STATIC_VOLUME)
+		av->used_ebs = be32_to_cpu(new_vh->used_ebs);
+
+	av->leb_count++;
+
+	rb_link_node(&new_aeb->u.rb, parent, p);
+	rb_insert_color(&new_aeb->u.rb, &av->root);
+
+	return 0;
+}
+
+/**
+ * process_pool_aeb - we found a non-empty PEB in a pool.
+ * @ubi: UBI device object
+ * @ai: attach info object
+ * @new_vh: the volume header derived from new_aeb
+ * @new_aeb: the AEB to be examined
+ *
+ * Returns 0 on success, < 0 indicates an internal error.
+ */
+static int process_pool_aeb(struct ubi_device *ubi, struct ubi_attach_info *ai,
+			    struct ubi_vid_hdr *new_vh,
+			    struct ubi_ainf_peb *new_aeb)
+{
+	int vol_id = be32_to_cpu(new_vh->vol_id);
+	struct ubi_ainf_volume *av;
+
+	if (vol_id == UBI_FM_SB_VOLUME_ID || vol_id == UBI_FM_DATA_VOLUME_ID) {
+		ubi_free_aeb(ai, new_aeb);
+
+		return 0;
+	}
+
+	/* Find the volume this SEB belongs to */
+	av = ubi_find_av(ai, vol_id);
+	if (!av) {
+		ubi_err(ubi, "orphaned volume in fastmap pool!");
+		ubi_free_aeb(ai, new_aeb);
+		return UBI_BAD_FASTMAP;
+	}
+
+	ubi_assert(vol_id == av->vol_id);
+
+	return update_vol(ubi, ai, av, new_vh, new_aeb);
+}
+
+/**
+ * unmap_peb - unmap a PEB.
+ * If fastmap detects a free PEB in the pool it has to check whether
+ * this PEB has been unmapped after writing the fastmap.
+ *
+ * @ai: UBI attach info object
+ * @pnum: The PEB to be unmapped
+ */
+static void unmap_peb(struct ubi_attach_info *ai, int pnum)
+{
+	struct ubi_ainf_volume *av;
+	struct rb_node *node, *node2;
+	struct ubi_ainf_peb *aeb;
+
+	ubi_rb_for_each_entry(node, av, &ai->volumes, rb) {
+		ubi_rb_for_each_entry(node2, aeb, &av->root, u.rb) {
+			if (aeb->pnum == pnum) {
+				rb_erase(&aeb->u.rb, &av->root);
+				av->leb_count--;
+				ubi_free_aeb(ai, aeb);
+				return;
+			}
+		}
+	}
+}
+
+/**
+ * scan_pool - scans a pool for changed (no longer empty PEBs).
+ * @ubi: UBI device object
+ * @ai: attach info object
+ * @pebs: an array of all PEB numbers in the to be scanned pool
+ * @pool_size: size of the pool (number of entries in @pebs)
+ * @max_sqnum: pointer to the maximal sequence number
+ * @free: list of PEBs which are most likely free (and go into @ai->free)
+ *
+ * Returns 0 on success, if the pool is unusable UBI_BAD_FASTMAP is returned.
+ * < 0 indicates an internal error.
+ */
+static int scan_pool(struct ubi_device *ubi, struct ubi_attach_info *ai,
+		     __be32 *pebs, int pool_size, unsigned long long *max_sqnum,
+		     struct list_head *free)
+{
+	struct ubi_vid_io_buf *vb;
+	struct ubi_vid_hdr *vh;
+	struct ubi_ec_hdr *ech;
+	struct ubi_ainf_peb *new_aeb;
+	int i, pnum, err, ret = 0;
+
+	ech = kzalloc(ubi->ec_hdr_alsize, GFP_KERNEL);
+	if (!ech)
+		return -ENOMEM;
+
+	vb = ubi_alloc_vid_buf(ubi, GFP_KERNEL);
+	if (!vb) {
+		kfree(ech);
+		return -ENOMEM;
+	}
+
+	vh = ubi_get_vid_hdr(vb);
+
+	dbg_bld("scanning fastmap pool: size = %i", pool_size);
+
+	/*
+	 * Now scan all PEBs in the pool to find changes which have been made
+	 * after the creation of the fastmap
+	 */
+	for (i = 0; i < pool_size; i++) {
+		int scrub = 0;
+		int image_seq;
+
+		pnum = be32_to_cpu(pebs[i]);
+
+		if (ubi_io_is_bad(ubi, pnum)) {
+			ubi_err(ubi, "bad PEB in fastmap pool!");
+			ret = UBI_BAD_FASTMAP;
+			goto out;
+		}
+
+		err = ubi_io_read_ec_hdr(ubi, pnum, ech, 0);
+		if (err && err != UBI_IO_BITFLIPS) {
+			ubi_err(ubi, "unable to read EC header! PEB:%i err:%i",
+				pnum, err);
+			ret = err > 0 ? UBI_BAD_FASTMAP : err;
+			goto out;
+		} else if (err == UBI_IO_BITFLIPS)
+			scrub = 1;
+
+		/*
+		 * Older UBI implementations have image_seq set to zero, so
+		 * we shouldn't fail if image_seq == 0.
+		 */
+		image_seq = be32_to_cpu(ech->image_seq);
+
+		if (image_seq && (image_seq != ubi->image_seq)) {
+			ubi_err(ubi, "bad image seq: 0x%x, expected: 0x%x",
+				be32_to_cpu(ech->image_seq), ubi->image_seq);
+			ret = UBI_BAD_FASTMAP;
+			goto out;
+		}
+
+		err = ubi_io_read_vid_hdr(ubi, pnum, vb, 0);
+		if (err == UBI_IO_FF || err == UBI_IO_FF_BITFLIPS) {
+			unsigned long long ec = be64_to_cpu(ech->ec);
+			unmap_peb(ai, pnum);
+			dbg_bld("Adding PEB to free: %i", pnum);
+
+			if (err == UBI_IO_FF_BITFLIPS)
+				scrub = 1;
+
+			ret = add_aeb(ai, free, pnum, ec, scrub);
+			if (ret)
+				goto out;
+			continue;
+		} else if (err == 0 || err == UBI_IO_BITFLIPS) {
+			dbg_bld("Found non empty PEB:%i in pool", pnum);
+
+			if (err == UBI_IO_BITFLIPS)
+				scrub = 1;
+
+			new_aeb = ubi_alloc_aeb(ai, pnum, be64_to_cpu(ech->ec));
+			if (!new_aeb) {
+				ret = -ENOMEM;
+				goto out;
+			}
+
+			new_aeb->lnum = be32_to_cpu(vh->lnum);
+			new_aeb->sqnum = be64_to_cpu(vh->sqnum);
+			new_aeb->copy_flag = vh->copy_flag;
+			new_aeb->scrub = scrub;
+
+			if (*max_sqnum < new_aeb->sqnum)
+				*max_sqnum = new_aeb->sqnum;
+
+			err = process_pool_aeb(ubi, ai, vh, new_aeb);
+			if (err) {
+				ret = err > 0 ? UBI_BAD_FASTMAP : err;
+				goto out;
+			}
+		} else {
+			/* We are paranoid and fall back to scanning mode */
+			ubi_err(ubi, "fastmap pool PEBs contains damaged PEBs!");
+			ret = err > 0 ? UBI_BAD_FASTMAP : err;
+			goto out;
+		}
+
+	}
+
+out:
+	ubi_free_vid_buf(vb);
+	kfree(ech);
+	return ret;
+}
+
+/**
+ * count_fastmap_pebs - Counts the PEBs found by fastmap.
+ * @ai: The UBI attach info object
+ */
+static int count_fastmap_pebs(struct ubi_attach_info *ai)
+{
+	struct ubi_ainf_peb *aeb;
+	struct ubi_ainf_volume *av;
+	struct rb_node *rb1, *rb2;
+	int n = 0;
+
+	list_for_each_entry(aeb, &ai->erase, u.list)
+		n++;
+
+	list_for_each_entry(aeb, &ai->free, u.list)
+		n++;
+
+	ubi_rb_for_each_entry(rb1, av, &ai->volumes, rb)
+		ubi_rb_for_each_entry(rb2, aeb, &av->root, u.rb)
+			n++;
+
+	return n;
+}
+
+/**
+ * ubi_attach_fastmap - creates ubi_attach_info from a fastmap.
+ * @ubi: UBI device object
+ * @ai: UBI attach info object
+ * @fm: the fastmap to be attached
+ *
+ * Returns 0 on success, UBI_BAD_FASTMAP if the found fastmap was unusable.
+ * < 0 indicates an internal error.
+ */
+static int ubi_attach_fastmap(struct ubi_device *ubi,
+			      struct ubi_attach_info *ai,
+			      struct ubi_fastmap_layout *fm)
+{
+	struct list_head used, free;
+	struct ubi_ainf_volume *av;
+	struct ubi_ainf_peb *aeb, *tmp_aeb, *_tmp_aeb;
+	struct ubi_fm_sb *fmsb;
+	struct ubi_fm_hdr *fmhdr;
+	struct ubi_fm_scan_pool *fmpl, *fmpl_wl;
+	struct ubi_fm_ec *fmec;
+	struct ubi_fm_volhdr *fmvhdr;
+	struct ubi_fm_eba *fm_eba;
+	int ret, i, j, pool_size, wl_pool_size;
+	size_t fm_pos = 0, fm_size = ubi->fm_size;
+	unsigned long long max_sqnum = 0;
+	void *fm_raw = ubi->fm_buf;
+
+	INIT_LIST_HEAD(&used);
+	INIT_LIST_HEAD(&free);
+	ai->min_ec = UBI_MAX_ERASECOUNTER;
+
+	fmsb = (struct ubi_fm_sb *)(fm_raw);
+	ai->max_sqnum = fmsb->sqnum;
+	fm_pos += sizeof(struct ubi_fm_sb);
+	if (fm_pos >= fm_size)
+		goto fail_bad;
+
+	fmhdr = (struct ubi_fm_hdr *)(fm_raw + fm_pos);
+	fm_pos += sizeof(*fmhdr);
+	if (fm_pos >= fm_size)
+		goto fail_bad;
+
+	if (be32_to_cpu(fmhdr->magic) != UBI_FM_HDR_MAGIC) {
+		ubi_err(ubi, "bad fastmap header magic: 0x%x, expected: 0x%x",
+			be32_to_cpu(fmhdr->magic), UBI_FM_HDR_MAGIC);
+		goto fail_bad;
+	}
+
+	fmpl = (struct ubi_fm_scan_pool *)(fm_raw + fm_pos);
+	fm_pos += sizeof(*fmpl);
+	if (fm_pos >= fm_size)
+		goto fail_bad;
+	if (be32_to_cpu(fmpl->magic) != UBI_FM_POOL_MAGIC) {
+		ubi_err(ubi, "bad fastmap pool magic: 0x%x, expected: 0x%x",
+			be32_to_cpu(fmpl->magic), UBI_FM_POOL_MAGIC);
+		goto fail_bad;
+	}
+
+	fmpl_wl = (struct ubi_fm_scan_pool *)(fm_raw + fm_pos);
+	fm_pos += sizeof(*fmpl_wl);
+	if (fm_pos >= fm_size)
+		goto fail_bad;
+	if (be32_to_cpu(fmpl_wl->magic) != UBI_FM_POOL_MAGIC) {
+		ubi_err(ubi, "bad fastmap WL pool magic: 0x%x, expected: 0x%x",
+			be32_to_cpu(fmpl_wl->magic), UBI_FM_POOL_MAGIC);
+		goto fail_bad;
+	}
+
+	pool_size = be16_to_cpu(fmpl->size);
+	wl_pool_size = be16_to_cpu(fmpl_wl->size);
+	fm->max_pool_size = be16_to_cpu(fmpl->max_size);
+	fm->max_wl_pool_size = be16_to_cpu(fmpl_wl->max_size);
+
+	if (pool_size > UBI_FM_MAX_POOL_SIZE || pool_size < 0) {
+		ubi_err(ubi, "bad pool size: %i", pool_size);
+		goto fail_bad;
+	}
+
+	if (wl_pool_size > UBI_FM_MAX_POOL_SIZE || wl_pool_size < 0) {
+		ubi_err(ubi, "bad WL pool size: %i", wl_pool_size);
+		goto fail_bad;
+	}
+
+
+	if (fm->max_pool_size > UBI_FM_MAX_POOL_SIZE ||
+	    fm->max_pool_size < 0) {
+		ubi_err(ubi, "bad maximal pool size: %i", fm->max_pool_size);
+		goto fail_bad;
+	}
+
+	if (fm->max_wl_pool_size > UBI_FM_MAX_POOL_SIZE ||
+	    fm->max_wl_pool_size < 0) {
+		ubi_err(ubi, "bad maximal WL pool size: %i",
+			fm->max_wl_pool_size);
+		goto fail_bad;
+	}
+
+	/* read EC values from free list */
+	for (i = 0; i < be32_to_cpu(fmhdr->free_peb_count); i++) {
+		fmec = (struct ubi_fm_ec *)(fm_raw + fm_pos);
+		fm_pos += sizeof(*fmec);
+		if (fm_pos >= fm_size)
+			goto fail_bad;
+
+		ret = add_aeb(ai, &ai->free, be32_to_cpu(fmec->pnum),
+			      be32_to_cpu(fmec->ec), 0);
+		if (ret)
+			goto fail;
+	}
+
+	/* read EC values from used list */
+	for (i = 0; i < be32_to_cpu(fmhdr->used_peb_count); i++) {
+		fmec = (struct ubi_fm_ec *)(fm_raw + fm_pos);
+		fm_pos += sizeof(*fmec);
+		if (fm_pos >= fm_size)
+			goto fail_bad;
+
+		ret = add_aeb(ai, &used, be32_to_cpu(fmec->pnum),
+			      be32_to_cpu(fmec->ec), 0);
+		if (ret)
+			goto fail;
+	}
+
+	/* read EC values from scrub list */
+	for (i = 0; i < be32_to_cpu(fmhdr->scrub_peb_count); i++) {
+		fmec = (struct ubi_fm_ec *)(fm_raw + fm_pos);
+		fm_pos += sizeof(*fmec);
+		if (fm_pos >= fm_size)
+			goto fail_bad;
+
+		ret = add_aeb(ai, &used, be32_to_cpu(fmec->pnum),
+			      be32_to_cpu(fmec->ec), 1);
+		if (ret)
+			goto fail;
+	}
+
+	/* read EC values from erase list */
+	for (i = 0; i < be32_to_cpu(fmhdr->erase_peb_count); i++) {
+		fmec = (struct ubi_fm_ec *)(fm_raw + fm_pos);
+		fm_pos += sizeof(*fmec);
+		if (fm_pos >= fm_size)
+			goto fail_bad;
+
+		ret = add_aeb(ai, &ai->erase, be32_to_cpu(fmec->pnum),
+			      be32_to_cpu(fmec->ec), 1);
+		if (ret)
+			goto fail;
+	}
+
+	ai->mean_ec = div_u64(ai->ec_sum, ai->ec_count);
+	ai->bad_peb_count = be32_to_cpu(fmhdr->bad_peb_count);
+
+	/* Iterate over all volumes and read their EBA table */
+	for (i = 0; i < be32_to_cpu(fmhdr->vol_count); i++) {
+		fmvhdr = (struct ubi_fm_volhdr *)(fm_raw + fm_pos);
+		fm_pos += sizeof(*fmvhdr);
+		if (fm_pos >= fm_size)
+			goto fail_bad;
+
+		if (be32_to_cpu(fmvhdr->magic) != UBI_FM_VHDR_MAGIC) {
+			ubi_err(ubi, "bad fastmap vol header magic: 0x%x, expected: 0x%x",
+				be32_to_cpu(fmvhdr->magic), UBI_FM_VHDR_MAGIC);
+			goto fail_bad;
+		}
+
+		av = add_vol(ai, be32_to_cpu(fmvhdr->vol_id),
+			     be32_to_cpu(fmvhdr->used_ebs),
+			     be32_to_cpu(fmvhdr->data_pad),
+			     fmvhdr->vol_type,
+			     be32_to_cpu(fmvhdr->last_eb_bytes));
+
+		if (IS_ERR(av)) {
+			if (PTR_ERR(av) == -EEXIST)
+				ubi_err(ubi, "volume (ID %i) already exists",
+					fmvhdr->vol_id);
+
+			goto fail_bad;
+		}
+
+		ai->vols_found++;
+		if (ai->highest_vol_id < be32_to_cpu(fmvhdr->vol_id))
+			ai->highest_vol_id = be32_to_cpu(fmvhdr->vol_id);
+
+		fm_eba = (struct ubi_fm_eba *)(fm_raw + fm_pos);
+		fm_pos += sizeof(*fm_eba);
+		fm_pos += (sizeof(__be32) * be32_to_cpu(fm_eba->reserved_pebs));
+		if (fm_pos >= fm_size)
+			goto fail_bad;
+
+		if (be32_to_cpu(fm_eba->magic) != UBI_FM_EBA_MAGIC) {
+			ubi_err(ubi, "bad fastmap EBA header magic: 0x%x, expected: 0x%x",
+				be32_to_cpu(fm_eba->magic), UBI_FM_EBA_MAGIC);
+			goto fail_bad;
+		}
+
+		for (j = 0; j < be32_to_cpu(fm_eba->reserved_pebs); j++) {
+			int pnum = be32_to_cpu(fm_eba->pnum[j]);
+
+			if (pnum < 0)
+				continue;
+
+			aeb = NULL;
+			list_for_each_entry(tmp_aeb, &used, u.list) {
+				if (tmp_aeb->pnum == pnum) {
+					aeb = tmp_aeb;
+					break;
+				}
+			}
+
+			if (!aeb) {
+				ubi_err(ubi, "PEB %i is in EBA but not in used list", pnum);
+				goto fail_bad;
+			}
+
+			aeb->lnum = j;
+
+			if (av->highest_lnum <= aeb->lnum)
+				av->highest_lnum = aeb->lnum;
+
+			assign_aeb_to_av(ai, aeb, av);
+
+			dbg_bld("inserting PEB:%i (LEB %i) to vol %i",
+				aeb->pnum, aeb->lnum, av->vol_id);
+		}
+	}
+
+	ret = scan_pool(ubi, ai, fmpl->pebs, pool_size, &max_sqnum, &free);
+	if (ret)
+		goto fail;
+
+	ret = scan_pool(ubi, ai, fmpl_wl->pebs, wl_pool_size, &max_sqnum, &free);
+	if (ret)
+		goto fail;
+
+	if (max_sqnum > ai->max_sqnum)
+		ai->max_sqnum = max_sqnum;
+
+	list_for_each_entry_safe(tmp_aeb, _tmp_aeb, &free, u.list)
+		list_move_tail(&tmp_aeb->u.list, &ai->free);
+
+	list_for_each_entry_safe(tmp_aeb, _tmp_aeb, &used, u.list)
+		list_move_tail(&tmp_aeb->u.list, &ai->erase);
+
+	ubi_assert(list_empty(&free));
+
+	/*
+	 * If fastmap is leaking PEBs (must not happen), raise a
+	 * fat warning and fall back to scanning mode.
+	 * We do this here because in ubi_wl_init() it's too late
+	 * and we cannot fall back to scanning.
+	 */
+	if (WARN_ON(count_fastmap_pebs(ai) != ubi->peb_count -
+		    ai->bad_peb_count - fm->used_blocks))
+		goto fail_bad;
+
+	return 0;
+
+fail_bad:
+	ret = UBI_BAD_FASTMAP;
+fail:
+	list_for_each_entry_safe(tmp_aeb, _tmp_aeb, &used, u.list) {
+		list_del(&tmp_aeb->u.list);
+		ubi_free_aeb(ai, tmp_aeb);
+	}
+	list_for_each_entry_safe(tmp_aeb, _tmp_aeb, &free, u.list) {
+		list_del(&tmp_aeb->u.list);
+		ubi_free_aeb(ai, tmp_aeb);
+	}
+
+	return ret;
+}
+
+/**
+ * find_fm_anchor - find the most recent Fastmap superblock (anchor)
+ * @ai: UBI attach info to be filled
+ */
+static int find_fm_anchor(struct ubi_attach_info *ai)
+{
+	int ret = -1;
+	struct ubi_ainf_peb *aeb;
+	unsigned long long max_sqnum = 0;
+
+	list_for_each_entry(aeb, &ai->fastmap, u.list) {
+		if (aeb->vol_id == UBI_FM_SB_VOLUME_ID && aeb->sqnum > max_sqnum) {
+			max_sqnum = aeb->sqnum;
+			ret = aeb->pnum;
+		}
+	}
+
+	return ret;
+}
+
+static struct ubi_ainf_peb *clone_aeb(struct ubi_attach_info *ai,
+				      struct ubi_ainf_peb *old)
+{
+	struct ubi_ainf_peb *new;
+
+	new = ubi_alloc_aeb(ai, old->pnum, old->ec);
+	if (!new)
+		return NULL;
+
+	new->vol_id = old->vol_id;
+	new->sqnum = old->sqnum;
+	new->lnum = old->lnum;
+	new->scrub = old->scrub;
+	new->copy_flag = old->copy_flag;
+
+	return new;
+}
+
+/**
+ * ubi_scan_fastmap - scan the fastmap.
+ * @ubi: UBI device object
+ * @ai: UBI attach info to be filled
+ * @scan_ai: UBI attach info from the first 64 PEBs,
+ *           used to find the most recent Fastmap data structure
+ *
+ * Returns 0 on success, UBI_NO_FASTMAP if no fastmap was found,
+ * UBI_BAD_FASTMAP if one was found but is not usable.
+ * < 0 indicates an internal error.
+ */
+int ubi_scan_fastmap(struct ubi_device *ubi, struct ubi_attach_info *ai,
+		     struct ubi_attach_info *scan_ai)
+{
+	struct ubi_fm_sb *fmsb, *fmsb2;
+	struct ubi_vid_io_buf *vb;
+	struct ubi_vid_hdr *vh;
+	struct ubi_ec_hdr *ech;
+	struct ubi_fastmap_layout *fm;
+	struct ubi_ainf_peb *aeb;
+	int i, used_blocks, pnum, fm_anchor, ret = 0;
+	size_t fm_size;
+	__be32 crc, tmp_crc;
+	unsigned long long sqnum = 0;
+
+	fm_anchor = find_fm_anchor(scan_ai);
+	if (fm_anchor < 0)
+		return UBI_NO_FASTMAP;
+
+	/* Copy all (possible) fastmap blocks into our new attach structure. */
+	list_for_each_entry(aeb, &scan_ai->fastmap, u.list) {
+		struct ubi_ainf_peb *new;
+
+		new = clone_aeb(ai, aeb);
+		if (!new)
+			return -ENOMEM;
+
+		list_add(&new->u.list, &ai->fastmap);
+	}
+
+	down_write(&ubi->fm_protect);
+	memset(ubi->fm_buf, 0, ubi->fm_size);
+
+	fmsb = kmalloc(sizeof(*fmsb), GFP_KERNEL);
+	if (!fmsb) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	fm = kzalloc(sizeof(*fm), GFP_KERNEL);
+	if (!fm) {
+		ret = -ENOMEM;
+		kfree(fmsb);
+		goto out;
+	}
+
+	ret = ubi_io_read_data(ubi, fmsb, fm_anchor, 0, sizeof(*fmsb));
+	if (ret && ret != UBI_IO_BITFLIPS)
+		goto free_fm_sb;
+	else if (ret == UBI_IO_BITFLIPS)
+		fm->to_be_tortured[0] = 1;
+
+	if (be32_to_cpu(fmsb->magic) != UBI_FM_SB_MAGIC) {
+		ubi_err(ubi, "bad super block magic: 0x%x, expected: 0x%x",
+			be32_to_cpu(fmsb->magic), UBI_FM_SB_MAGIC);
+		ret = UBI_BAD_FASTMAP;
+		goto free_fm_sb;
+	}
+
+	if (fmsb->version != UBI_FM_FMT_VERSION) {
+		ubi_err(ubi, "bad fastmap version: %i, expected: %i",
+			fmsb->version, UBI_FM_FMT_VERSION);
+		ret = UBI_BAD_FASTMAP;
+		goto free_fm_sb;
+	}
+
+	used_blocks = be32_to_cpu(fmsb->used_blocks);
+	if (used_blocks > UBI_FM_MAX_BLOCKS || used_blocks < 1) {
+		ubi_err(ubi, "number of fastmap blocks is invalid: %i",
+			used_blocks);
+		ret = UBI_BAD_FASTMAP;
+		goto free_fm_sb;
+	}
+
+	fm_size = ubi->leb_size * used_blocks;
+	if (fm_size != ubi->fm_size) {
+		ubi_err(ubi, "bad fastmap size: %zi, expected: %zi",
+			fm_size, ubi->fm_size);
+		ret = UBI_BAD_FASTMAP;
+		goto free_fm_sb;
+	}
+
+	ech = kzalloc(ubi->ec_hdr_alsize, GFP_KERNEL);
+	if (!ech) {
+		ret = -ENOMEM;
+		goto free_fm_sb;
+	}
+
+	vb = ubi_alloc_vid_buf(ubi, GFP_KERNEL);
+	if (!vb) {
+		ret = -ENOMEM;
+		goto free_hdr;
+	}
+
+	vh = ubi_get_vid_hdr(vb);
+
+	for (i = 0; i < used_blocks; i++) {
+		int image_seq;
+
+		pnum = be32_to_cpu(fmsb->block_loc[i]);
+
+		if (ubi_io_is_bad(ubi, pnum)) {
+			ret = UBI_BAD_FASTMAP;
+			goto free_hdr;
+		}
+
+		if (i == 0 && pnum != fm_anchor) {
+			ubi_err(ubi, "Fastmap anchor PEB mismatch: PEB: %i vs. %i",
+				pnum, fm_anchor);
+			ret = UBI_BAD_FASTMAP;
+			goto free_hdr;
+		}
+
+		ret = ubi_io_read_ec_hdr(ubi, pnum, ech, 0);
+		if (ret && ret != UBI_IO_BITFLIPS) {
+			ubi_err(ubi, "unable to read fastmap block# %i EC (PEB: %i)",
+				i, pnum);
+			if (ret > 0)
+				ret = UBI_BAD_FASTMAP;
+			goto free_hdr;
+		} else if (ret == UBI_IO_BITFLIPS)
+			fm->to_be_tortured[i] = 1;
+
+		image_seq = be32_to_cpu(ech->image_seq);
+		if (!ubi->image_seq)
+			ubi->image_seq = image_seq;
+
+		/*
+		 * Older UBI implementations have image_seq set to zero, so
+		 * we shouldn't fail if image_seq == 0.
+		 */
+		if (image_seq && (image_seq != ubi->image_seq)) {
+			ubi_err(ubi, "wrong image seq:%d instead of %d",
+				be32_to_cpu(ech->image_seq), ubi->image_seq);
+			ret = UBI_BAD_FASTMAP;
+			goto free_hdr;
+		}
+
+		ret = ubi_io_read_vid_hdr(ubi, pnum, vb, 0);
+		if (ret && ret != UBI_IO_BITFLIPS) {
+			ubi_err(ubi, "unable to read fastmap block# %i (PEB: %i)",
+				i, pnum);
+			goto free_hdr;
+		}
+
+		if (i == 0) {
+			if (be32_to_cpu(vh->vol_id) != UBI_FM_SB_VOLUME_ID) {
+				ubi_err(ubi, "bad fastmap anchor vol_id: 0x%x, expected: 0x%x",
+					be32_to_cpu(vh->vol_id),
+					UBI_FM_SB_VOLUME_ID);
+				ret = UBI_BAD_FASTMAP;
+				goto free_hdr;
+			}
+		} else {
+			if (be32_to_cpu(vh->vol_id) != UBI_FM_DATA_VOLUME_ID) {
+				ubi_err(ubi, "bad fastmap data vol_id: 0x%x, expected: 0x%x",
+					be32_to_cpu(vh->vol_id),
+					UBI_FM_DATA_VOLUME_ID);
+				ret = UBI_BAD_FASTMAP;
+				goto free_hdr;
+			}
+		}
+
+		if (sqnum < be64_to_cpu(vh->sqnum))
+			sqnum = be64_to_cpu(vh->sqnum);
+
+		ret = ubi_io_read_data(ubi, ubi->fm_buf + (ubi->leb_size * i),
+				       pnum, 0, ubi->leb_size);
+		if (ret && ret != UBI_IO_BITFLIPS) {
+			ubi_err(ubi, "unable to read fastmap block# %i (PEB: %i, "
+				"err: %i)", i, pnum, ret);
+			goto free_hdr;
+		}
+	}
+
+	kfree(fmsb);
+	fmsb = NULL;
+
+	fmsb2 = (struct ubi_fm_sb *)(ubi->fm_buf);
+	tmp_crc = be32_to_cpu(fmsb2->data_crc);
+	fmsb2->data_crc = 0;
+	crc = crc32(UBI_CRC32_INIT, ubi->fm_buf, fm_size);
+	if (crc != tmp_crc) {
+		ubi_err(ubi, "fastmap data CRC is invalid");
+		ubi_err(ubi, "CRC should be: 0x%x, calc: 0x%x",
+			tmp_crc, crc);
+		ret = UBI_BAD_FASTMAP;
+		goto free_hdr;
+	}
+
+	fmsb2->sqnum = sqnum;
+
+	fm->used_blocks = used_blocks;
+
+	ret = ubi_attach_fastmap(ubi, ai, fm);
+	if (ret) {
+		if (ret > 0)
+			ret = UBI_BAD_FASTMAP;
+		goto free_hdr;
+	}
+
+	for (i = 0; i < used_blocks; i++) {
+		struct ubi_wl_entry *e;
+
+		e = kmem_cache_alloc(ubi_wl_entry_slab, GFP_KERNEL);
+		if (!e) {
+			while (i--)
+				kmem_cache_free(ubi_wl_entry_slab, fm->e[i]);
+
+			ret = -ENOMEM;
+			goto free_hdr;
+		}
+
+		e->pnum = be32_to_cpu(fmsb2->block_loc[i]);
+		e->ec = be32_to_cpu(fmsb2->block_ec[i]);
+		fm->e[i] = e;
+	}
+
+	ubi->fm = fm;
+	ubi->fm_pool.max_size = ubi->fm->max_pool_size;
+	ubi->fm_wl_pool.max_size = ubi->fm->max_wl_pool_size;
+	ubi_msg(ubi, "attached by fastmap");
+	ubi_msg(ubi, "fastmap pool size: %d", ubi->fm_pool.max_size);
+	ubi_msg(ubi, "fastmap WL pool size: %d",
+		ubi->fm_wl_pool.max_size);
+	ubi->fm_disabled = 0;
+	ubi->fast_attach = 1;
+
+	ubi_free_vid_buf(vb);
+	kfree(ech);
+out:
+	up_write(&ubi->fm_protect);
+	if (ret == UBI_BAD_FASTMAP)
+		ubi_err(ubi, "Attach by fastmap failed, doing a full scan!");
+	return ret;
+
+free_hdr:
+	ubi_free_vid_buf(vb);
+	kfree(ech);
+free_fm_sb:
+	kfree(fmsb);
+	kfree(fm);
+	goto out;
+}
+
+int ubi_fastmap_init_checkmap(struct ubi_volume *vol, int leb_count)
+{
+	struct ubi_device *ubi = vol->ubi;
+
+	if (!ubi->fast_attach)
+		return 0;
+
+	vol->checkmap = kcalloc(BITS_TO_LONGS(leb_count), sizeof(unsigned long),
+				GFP_KERNEL);
+	if (!vol->checkmap)
+		return -ENOMEM;
+
+	return 0;
+}
+
+void ubi_fastmap_destroy_checkmap(struct ubi_volume *vol)
+{
+	kfree(vol->checkmap);
+}
+
+/**
+ * ubi_write_fastmap - writes a fastmap.
+ * @ubi: UBI device object
+ * @new_fm: the to be written fastmap
+ *
+ * Returns 0 on success, < 0 indicates an internal error.
+ */
+static int ubi_write_fastmap(struct ubi_device *ubi,
+			     struct ubi_fastmap_layout *new_fm)
+{
+	size_t fm_pos = 0;
+	void *fm_raw;
+	struct ubi_fm_sb *fmsb;
+	struct ubi_fm_hdr *fmh;
+	struct ubi_fm_scan_pool *fmpl, *fmpl_wl;
+	struct ubi_fm_ec *fec;
+	struct ubi_fm_volhdr *fvh;
+	struct ubi_fm_eba *feba;
+	struct ubi_wl_entry *wl_e;
+	struct ubi_volume *vol;
+	struct ubi_vid_io_buf *avbuf, *dvbuf;
+	struct ubi_vid_hdr *avhdr, *dvhdr;
+	struct ubi_work *ubi_wrk;
+	struct rb_node *tmp_rb;
+	int ret, i, j, free_peb_count, used_peb_count, vol_count;
+	int scrub_peb_count, erase_peb_count;
+	unsigned long *seen_pebs;
+
+	fm_raw = ubi->fm_buf;
+	memset(ubi->fm_buf, 0, ubi->fm_size);
+
+	avbuf = new_fm_vbuf(ubi, UBI_FM_SB_VOLUME_ID);
+	if (!avbuf) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	dvbuf = new_fm_vbuf(ubi, UBI_FM_DATA_VOLUME_ID);
+	if (!dvbuf) {
+		ret = -ENOMEM;
+		goto out_free_avbuf;
+	}
+
+	avhdr = ubi_get_vid_hdr(avbuf);
+	dvhdr = ubi_get_vid_hdr(dvbuf);
+
+	seen_pebs = init_seen(ubi);
+	if (IS_ERR(seen_pebs)) {
+		ret = PTR_ERR(seen_pebs);
+		goto out_free_dvbuf;
+	}
+
+	spin_lock(&ubi->volumes_lock);
+	spin_lock(&ubi->wl_lock);
+
+	fmsb = (struct ubi_fm_sb *)fm_raw;
+	fm_pos += sizeof(*fmsb);
+	ubi_assert(fm_pos <= ubi->fm_size);
+
+	fmh = (struct ubi_fm_hdr *)(fm_raw + fm_pos);
+	fm_pos += sizeof(*fmh);
+	ubi_assert(fm_pos <= ubi->fm_size);
+
+	fmsb->magic = cpu_to_be32(UBI_FM_SB_MAGIC);
+	fmsb->version = UBI_FM_FMT_VERSION;
+	fmsb->used_blocks = cpu_to_be32(new_fm->used_blocks);
+	/* the max sqnum will be filled in while *reading* the fastmap */
+	fmsb->sqnum = 0;
+
+	fmh->magic = cpu_to_be32(UBI_FM_HDR_MAGIC);
+	free_peb_count = 0;
+	used_peb_count = 0;
+	scrub_peb_count = 0;
+	erase_peb_count = 0;
+	vol_count = 0;
+
+	fmpl = (struct ubi_fm_scan_pool *)(fm_raw + fm_pos);
+	fm_pos += sizeof(*fmpl);
+	fmpl->magic = cpu_to_be32(UBI_FM_POOL_MAGIC);
+	fmpl->size = cpu_to_be16(ubi->fm_pool.size);
+	fmpl->max_size = cpu_to_be16(ubi->fm_pool.max_size);
+
+	for (i = 0; i < ubi->fm_pool.size; i++) {
+		fmpl->pebs[i] = cpu_to_be32(ubi->fm_pool.pebs[i]);
+		set_seen(ubi, ubi->fm_pool.pebs[i], seen_pebs);
+	}
+
+	fmpl_wl = (struct ubi_fm_scan_pool *)(fm_raw + fm_pos);
+	fm_pos += sizeof(*fmpl_wl);
+	fmpl_wl->magic = cpu_to_be32(UBI_FM_POOL_MAGIC);
+	fmpl_wl->size = cpu_to_be16(ubi->fm_wl_pool.size);
+	fmpl_wl->max_size = cpu_to_be16(ubi->fm_wl_pool.max_size);
+
+	for (i = 0; i < ubi->fm_wl_pool.size; i++) {
+		fmpl_wl->pebs[i] = cpu_to_be32(ubi->fm_wl_pool.pebs[i]);
+		set_seen(ubi, ubi->fm_wl_pool.pebs[i], seen_pebs);
+	}
+
+	ubi_for_each_free_peb(ubi, wl_e, tmp_rb) {
+		fec = (struct ubi_fm_ec *)(fm_raw + fm_pos);
+
+		fec->pnum = cpu_to_be32(wl_e->pnum);
+		set_seen(ubi, wl_e->pnum, seen_pebs);
+		fec->ec = cpu_to_be32(wl_e->ec);
+
+		free_peb_count++;
+		fm_pos += sizeof(*fec);
+		ubi_assert(fm_pos <= ubi->fm_size);
+	}
+	fmh->free_peb_count = cpu_to_be32(free_peb_count);
+
+	ubi_for_each_used_peb(ubi, wl_e, tmp_rb) {
+		fec = (struct ubi_fm_ec *)(fm_raw + fm_pos);
+
+		fec->pnum = cpu_to_be32(wl_e->pnum);
+		set_seen(ubi, wl_e->pnum, seen_pebs);
+		fec->ec = cpu_to_be32(wl_e->ec);
+
+		used_peb_count++;
+		fm_pos += sizeof(*fec);
+		ubi_assert(fm_pos <= ubi->fm_size);
+	}
+
+	ubi_for_each_protected_peb(ubi, i, wl_e) {
+		fec = (struct ubi_fm_ec *)(fm_raw + fm_pos);
+
+		fec->pnum = cpu_to_be32(wl_e->pnum);
+		set_seen(ubi, wl_e->pnum, seen_pebs);
+		fec->ec = cpu_to_be32(wl_e->ec);
+
+		used_peb_count++;
+		fm_pos += sizeof(*fec);
+		ubi_assert(fm_pos <= ubi->fm_size);
+	}
+	fmh->used_peb_count = cpu_to_be32(used_peb_count);
+
+	ubi_for_each_scrub_peb(ubi, wl_e, tmp_rb) {
+		fec = (struct ubi_fm_ec *)(fm_raw + fm_pos);
+
+		fec->pnum = cpu_to_be32(wl_e->pnum);
+		set_seen(ubi, wl_e->pnum, seen_pebs);
+		fec->ec = cpu_to_be32(wl_e->ec);
+
+		scrub_peb_count++;
+		fm_pos += sizeof(*fec);
+		ubi_assert(fm_pos <= ubi->fm_size);
+	}
+	fmh->scrub_peb_count = cpu_to_be32(scrub_peb_count);
+
+
+	list_for_each_entry(ubi_wrk, &ubi->works, list) {
+		if (ubi_is_erase_work(ubi_wrk)) {
+			wl_e = ubi_wrk->e;
+			ubi_assert(wl_e);
+
+			fec = (struct ubi_fm_ec *)(fm_raw + fm_pos);
+
+			fec->pnum = cpu_to_be32(wl_e->pnum);
+			set_seen(ubi, wl_e->pnum, seen_pebs);
+			fec->ec = cpu_to_be32(wl_e->ec);
+
+			erase_peb_count++;
+			fm_pos += sizeof(*fec);
+			ubi_assert(fm_pos <= ubi->fm_size);
+		}
+	}
+	fmh->erase_peb_count = cpu_to_be32(erase_peb_count);
+
+	for (i = 0; i < UBI_MAX_VOLUMES + UBI_INT_VOL_COUNT; i++) {
+		vol = ubi->volumes[i];
+
+		if (!vol)
+			continue;
+
+		vol_count++;
+
+		fvh = (struct ubi_fm_volhdr *)(fm_raw + fm_pos);
+		fm_pos += sizeof(*fvh);
+		ubi_assert(fm_pos <= ubi->fm_size);
+
+		fvh->magic = cpu_to_be32(UBI_FM_VHDR_MAGIC);
+		fvh->vol_id = cpu_to_be32(vol->vol_id);
+		fvh->vol_type = vol->vol_type;
+		fvh->used_ebs = cpu_to_be32(vol->used_ebs);
+		fvh->data_pad = cpu_to_be32(vol->data_pad);
+		fvh->last_eb_bytes = cpu_to_be32(vol->last_eb_bytes);
+
+		ubi_assert(vol->vol_type == UBI_DYNAMIC_VOLUME ||
+			vol->vol_type == UBI_STATIC_VOLUME);
+
+		feba = (struct ubi_fm_eba *)(fm_raw + fm_pos);
+		fm_pos += sizeof(*feba) + (sizeof(__be32) * vol->reserved_pebs);
+		ubi_assert(fm_pos <= ubi->fm_size);
+
+		for (j = 0; j < vol->reserved_pebs; j++) {
+			struct ubi_eba_leb_desc ldesc;
+
+			ubi_eba_get_ldesc(vol, j, &ldesc);
+			feba->pnum[j] = cpu_to_be32(ldesc.pnum);
+		}
+
+		feba->reserved_pebs = cpu_to_be32(j);
+		feba->magic = cpu_to_be32(UBI_FM_EBA_MAGIC);
+	}
+	fmh->vol_count = cpu_to_be32(vol_count);
+	fmh->bad_peb_count = cpu_to_be32(ubi->bad_peb_count);
+
+	avhdr->sqnum = cpu_to_be64(ubi_next_sqnum(ubi));
+	avhdr->lnum = 0;
+
+	spin_unlock(&ubi->wl_lock);
+	spin_unlock(&ubi->volumes_lock);
+
+	dbg_bld("writing fastmap SB to PEB %i", new_fm->e[0]->pnum);
+	ret = ubi_io_write_vid_hdr(ubi, new_fm->e[0]->pnum, avbuf);
+	if (ret) {
+		ubi_err(ubi, "unable to write vid_hdr to fastmap SB!");
+		goto out_free_seen;
+	}
+
+	for (i = 0; i < new_fm->used_blocks; i++) {
+		fmsb->block_loc[i] = cpu_to_be32(new_fm->e[i]->pnum);
+		set_seen(ubi, new_fm->e[i]->pnum, seen_pebs);
+		fmsb->block_ec[i] = cpu_to_be32(new_fm->e[i]->ec);
+	}
+
+	fmsb->data_crc = 0;
+	fmsb->data_crc = cpu_to_be32(crc32(UBI_CRC32_INIT, fm_raw,
+					   ubi->fm_size));
+
+	for (i = 1; i < new_fm->used_blocks; i++) {
+		dvhdr->sqnum = cpu_to_be64(ubi_next_sqnum(ubi));
+		dvhdr->lnum = cpu_to_be32(i);
+		dbg_bld("writing fastmap data to PEB %i sqnum %llu",
+			new_fm->e[i]->pnum, be64_to_cpu(dvhdr->sqnum));
+		ret = ubi_io_write_vid_hdr(ubi, new_fm->e[i]->pnum, dvbuf);
+		if (ret) {
+			ubi_err(ubi, "unable to write vid_hdr to PEB %i!",
+				new_fm->e[i]->pnum);
+			goto out_free_seen;
+		}
+	}
+
+	for (i = 0; i < new_fm->used_blocks; i++) {
+		ret = ubi_io_write_data(ubi, fm_raw + (i * ubi->leb_size),
+					new_fm->e[i]->pnum, 0, ubi->leb_size);
+		if (ret) {
+			ubi_err(ubi, "unable to write fastmap to PEB %i!",
+				new_fm->e[i]->pnum);
+			goto out_free_seen;
+		}
+	}
+
+	ubi_assert(new_fm);
+	ubi->fm = new_fm;
+
+	ret = self_check_seen(ubi, seen_pebs);
+	dbg_bld("fastmap written!");
+
+out_free_seen:
+	free_seen(seen_pebs);
+out_free_dvbuf:
+	ubi_free_vid_buf(dvbuf);
+out_free_avbuf:
+	ubi_free_vid_buf(avbuf);
+
+out:
+	return ret;
+}
+
+/**
+ * erase_block - Manually erase a PEB.
+ * @ubi: UBI device object
+ * @pnum: PEB to be erased
+ *
+ * Returns the new EC value on success, < 0 indicates an internal error.
+ */
+static int erase_block(struct ubi_device *ubi, int pnum)
+{
+	int ret;
+	struct ubi_ec_hdr *ec_hdr;
+	long long ec;
+
+	ec_hdr = kzalloc(ubi->ec_hdr_alsize, GFP_KERNEL);
+	if (!ec_hdr)
+		return -ENOMEM;
+
+	ret = ubi_io_read_ec_hdr(ubi, pnum, ec_hdr, 0);
+	if (ret < 0)
+		goto out;
+	else if (ret && ret != UBI_IO_BITFLIPS) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	ret = ubi_io_sync_erase(ubi, pnum, 0);
+	if (ret < 0)
+		goto out;
+
+	ec = be64_to_cpu(ec_hdr->ec);
+	ec += ret;
+	if (ec > UBI_MAX_ERASECOUNTER) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	ec_hdr->ec = cpu_to_be64(ec);
+	ret = ubi_io_write_ec_hdr(ubi, pnum, ec_hdr);
+	if (ret < 0)
+		goto out;
+
+	ret = ec;
+out:
+	kfree(ec_hdr);
+	return ret;
+}
+
+/**
+ * invalidate_fastmap - destroys a fastmap.
+ * @ubi: UBI device object
+ *
+ * This function ensures that upon next UBI attach a full scan
+ * is issued. We need this if UBI is about to write a new fastmap
+ * but is unable to do so. In this case we have two options:
+ * a) Make sure that the current fastmap will not be usued upon
+ * attach time and contine or b) fall back to RO mode to have the
+ * current fastmap in a valid state.
+ * Returns 0 on success, < 0 indicates an internal error.
+ */
+static int invalidate_fastmap(struct ubi_device *ubi)
+{
+	int ret;
+	struct ubi_fastmap_layout *fm;
+	struct ubi_wl_entry *e;
+	struct ubi_vid_io_buf *vb = NULL;
+	struct ubi_vid_hdr *vh;
+
+	if (!ubi->fm)
+		return 0;
+
+	ubi->fm = NULL;
+
+	ret = -ENOMEM;
+	fm = kzalloc(sizeof(*fm), GFP_KERNEL);
+	if (!fm)
+		goto out;
+
+	vb = new_fm_vbuf(ubi, UBI_FM_SB_VOLUME_ID);
+	if (!vb)
+		goto out_free_fm;
+
+	vh = ubi_get_vid_hdr(vb);
+
+	ret = -ENOSPC;
+	e = ubi_wl_get_fm_peb(ubi, 1);
+	if (!e)
+		goto out_free_fm;
+
+	/*
+	 * Create fake fastmap such that UBI will fall back
+	 * to scanning mode.
+	 */
+	vh->sqnum = cpu_to_be64(ubi_next_sqnum(ubi));
+	ret = ubi_io_write_vid_hdr(ubi, e->pnum, vb);
+	if (ret < 0) {
+		ubi_wl_put_fm_peb(ubi, e, 0, 0);
+		goto out_free_fm;
+	}
+
+	fm->used_blocks = 1;
+	fm->e[0] = e;
+
+	ubi->fm = fm;
+
+out:
+	ubi_free_vid_buf(vb);
+	return ret;
+
+out_free_fm:
+	kfree(fm);
+	goto out;
+}
+
+/**
+ * return_fm_pebs - returns all PEBs used by a fastmap back to the
+ * WL sub-system.
+ * @ubi: UBI device object
+ * @fm: fastmap layout object
+ */
+static void return_fm_pebs(struct ubi_device *ubi,
+			   struct ubi_fastmap_layout *fm)
+{
+	int i;
+
+	if (!fm)
+		return;
+
+	for (i = 0; i < fm->used_blocks; i++) {
+		if (fm->e[i]) {
+			ubi_wl_put_fm_peb(ubi, fm->e[i], i,
+					  fm->to_be_tortured[i]);
+			fm->e[i] = NULL;
+		}
+	}
+}
+
+/**
+ * ubi_update_fastmap - will be called by UBI if a volume changes or
+ * a fastmap pool becomes full.
+ * @ubi: UBI device object
+ *
+ * Returns 0 on success, < 0 indicates an internal error.
+ */
+int ubi_update_fastmap(struct ubi_device *ubi)
+{
+	int ret, i, j;
+	struct ubi_fastmap_layout *new_fm, *old_fm;
+	struct ubi_wl_entry *tmp_e;
+
+	down_write(&ubi->fm_protect);
+	down_write(&ubi->work_sem);
+	down_write(&ubi->fm_eba_sem);
+
+	ubi_refill_pools(ubi);
+
+	if (ubi->ro_mode || ubi->fm_disabled) {
+		up_write(&ubi->fm_eba_sem);
+		up_write(&ubi->work_sem);
+		up_write(&ubi->fm_protect);
+		return 0;
+	}
+
+	new_fm = kzalloc(sizeof(*new_fm), GFP_KERNEL);
+	if (!new_fm) {
+		up_write(&ubi->fm_eba_sem);
+		up_write(&ubi->work_sem);
+		up_write(&ubi->fm_protect);
+		return -ENOMEM;
+	}
+
+	new_fm->used_blocks = ubi->fm_size / ubi->leb_size;
+	old_fm = ubi->fm;
+	ubi->fm = NULL;
+
+	if (new_fm->used_blocks > UBI_FM_MAX_BLOCKS) {
+		ubi_err(ubi, "fastmap too large");
+		ret = -ENOSPC;
+		goto err;
+	}
+
+	for (i = 1; i < new_fm->used_blocks; i++) {
+		spin_lock(&ubi->wl_lock);
+		tmp_e = ubi_wl_get_fm_peb(ubi, 0);
+		spin_unlock(&ubi->wl_lock);
+
+		if (!tmp_e) {
+			if (old_fm && old_fm->e[i]) {
+				ret = erase_block(ubi, old_fm->e[i]->pnum);
+				if (ret < 0) {
+					ubi_err(ubi, "could not erase old fastmap PEB");
+
+					for (j = 1; j < i; j++) {
+						ubi_wl_put_fm_peb(ubi, new_fm->e[j],
+								  j, 0);
+						new_fm->e[j] = NULL;
+					}
+					goto err;
+				}
+				new_fm->e[i] = old_fm->e[i];
+				old_fm->e[i] = NULL;
+			} else {
+				ubi_err(ubi, "could not get any free erase block");
+
+				for (j = 1; j < i; j++) {
+					ubi_wl_put_fm_peb(ubi, new_fm->e[j], j, 0);
+					new_fm->e[j] = NULL;
+				}
+
+				ret = -ENOSPC;
+				goto err;
+			}
+		} else {
+			new_fm->e[i] = tmp_e;
+
+			if (old_fm && old_fm->e[i]) {
+				ubi_wl_put_fm_peb(ubi, old_fm->e[i], i,
+						  old_fm->to_be_tortured[i]);
+				old_fm->e[i] = NULL;
+			}
+		}
+	}
+
+	/* Old fastmap is larger than the new one */
+	if (old_fm && new_fm->used_blocks < old_fm->used_blocks) {
+		for (i = new_fm->used_blocks; i < old_fm->used_blocks; i++) {
+			ubi_wl_put_fm_peb(ubi, old_fm->e[i], i,
+					  old_fm->to_be_tortured[i]);
+			old_fm->e[i] = NULL;
+		}
+	}
+
+	spin_lock(&ubi->wl_lock);
+	tmp_e = ubi->fm_anchor;
+	ubi->fm_anchor = NULL;
+	spin_unlock(&ubi->wl_lock);
+
+	if (old_fm) {
+		/* no fresh anchor PEB was found, reuse the old one */
+		if (!tmp_e) {
+			ret = erase_block(ubi, old_fm->e[0]->pnum);
+			if (ret < 0) {
+				ubi_err(ubi, "could not erase old anchor PEB");
+
+				for (i = 1; i < new_fm->used_blocks; i++) {
+					ubi_wl_put_fm_peb(ubi, new_fm->e[i],
+							  i, 0);
+					new_fm->e[i] = NULL;
+				}
+				goto err;
+			}
+			new_fm->e[0] = old_fm->e[0];
+			new_fm->e[0]->ec = ret;
+			old_fm->e[0] = NULL;
+		} else {
+			/* we've got a new anchor PEB, return the old one */
+			ubi_wl_put_fm_peb(ubi, old_fm->e[0], 0,
+					  old_fm->to_be_tortured[0]);
+			new_fm->e[0] = tmp_e;
+			old_fm->e[0] = NULL;
+		}
+	} else {
+		if (!tmp_e) {
+			ubi_err(ubi, "could not find any anchor PEB");
+
+			for (i = 1; i < new_fm->used_blocks; i++) {
+				ubi_wl_put_fm_peb(ubi, new_fm->e[i], i, 0);
+				new_fm->e[i] = NULL;
+			}
+
+			ret = -ENOSPC;
+			goto err;
+		}
+		new_fm->e[0] = tmp_e;
+	}
+
+	ret = ubi_write_fastmap(ubi, new_fm);
+
+	if (ret)
+		goto err;
+
+out_unlock:
+	up_write(&ubi->fm_eba_sem);
+	up_write(&ubi->work_sem);
+	up_write(&ubi->fm_protect);
+	kfree(old_fm);
+
+	ubi_ensure_anchor_pebs(ubi);
+
+	return ret;
+
+err:
+	ubi_warn(ubi, "Unable to write new fastmap, err=%i", ret);
+
+	ret = invalidate_fastmap(ubi);
+	if (ret < 0) {
+		ubi_err(ubi, "Unable to invalidate current fastmap!");
+		ubi_ro_mode(ubi);
+	} else {
+		return_fm_pebs(ubi, old_fm);
+		return_fm_pebs(ubi, new_fm);
+		ret = 0;
+	}
+
+	kfree(new_fm);
+	goto out_unlock;
+}