UBI: Add fastmap core
authorRichard Weinberger <richard@nod.at>
Wed, 26 Sep 2012 15:51:49 +0000 (17:51 +0200)
committerArtem Bityutskiy <artem.bityutskiy@linux.intel.com>
Wed, 3 Oct 2012 13:39:27 +0000 (16:39 +0300)
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
drivers/mtd/ubi/fastmap.c [new file with mode: 0644]

diff --git a/drivers/mtd/ubi/fastmap.c b/drivers/mtd/ubi/fastmap.c
new file mode 100644 (file)
index 0000000..1a5f53c
--- /dev/null
@@ -0,0 +1,1537 @@
+/*
+ * Copyright (c) 2012 Linutronix GmbH
+ * Author: Richard Weinberger <richard@nod.at>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
+ * the GNU General Public License for more details.
+ *
+ */
+
+#include <linux/crc32.h>
+#include "ubi.h"
+
+/**
+ * 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_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_hdr *new_fm_vhdr(struct ubi_device *ubi, int vol_id)
+{
+       struct ubi_vid_hdr *new;
+
+       new = ubi_zalloc_vid_hdr(ubi, GFP_KERNEL);
+       if (!new)
+               goto out;
+
+       new->vol_type = UBI_VID_DYNAMIC;
+       new->vol_id = cpu_to_be32(vol_id);
+
+       /* UBI implementations without fastmap support have to delete the
+        * fastmap.
+        */
+       new->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 = kmem_cache_alloc(ai->aeb_slab_cache, GFP_KERNEL);
+       if (!aeb)
+               return -ENOMEM;
+
+       aeb->pnum = pnum;
+       aeb->ec = ec;
+       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;
+       struct rb_node **p = &ai->volumes.rb_node, *parent = NULL;
+
+       while (*p) {
+               parent = *p;
+               av = rb_entry(parent, struct ubi_ainf_volume, rb);
+
+               if (vol_id > av->vol_id)
+                       p = &(*p)->rb_left;
+               else if (vol_id > av->vol_id)
+                       p = &(*p)->rb_right;
+       }
+
+       av = kmalloc(sizeof(struct ubi_ainf_volume), GFP_KERNEL);
+       if (!av)
+               goto out;
+
+       av->highest_lnum = av->leb_count = 0;
+       av->vol_id = vol_id;
+       av->used_ebs = used_ebs;
+       av->data_pad = data_pad;
+       av->last_data_size = last_eb_bytes;
+       av->compat = 0;
+       av->vol_type = vol_type;
+       av->root = RB_ROOT;
+
+       dbg_bld("found volume (ID %i)", vol_id);
+
+       rb_link_node(&av->rb, parent, p);
+       rb_insert_color(&av->rb, &ai->volumes);
+
+out:
+       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 = &ai->volumes.rb_node, *parent = NULL;
+
+       p = &av->root.rb_node;
+       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);
+                       kmem_cache_free(ai->aeb_slab_cache, 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 = kmem_cache_alloc(ai->aeb_slab_cache,
+                               GFP_KERNEL);
+                       if (!victim)
+                               return -ENOMEM;
+
+                       victim->ec = aeb->ec;
+                       victim->pnum = aeb->pnum;
+                       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;
+                       kmem_cache_free(ai->aeb_slab_cache, 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)
+{
+       struct ubi_ainf_volume *av, *tmp_av = NULL;
+       struct rb_node **p = &ai->volumes.rb_node, *parent = NULL;
+       int found = 0;
+
+       if (be32_to_cpu(new_vh->vol_id) == UBI_FM_SB_VOLUME_ID ||
+               be32_to_cpu(new_vh->vol_id) == UBI_FM_DATA_VOLUME_ID) {
+               kmem_cache_free(ai->aeb_slab_cache, new_aeb);
+
+               return 0;
+       }
+
+       /* Find the volume this SEB belongs to */
+       while (*p) {
+               parent = *p;
+               tmp_av = rb_entry(parent, struct ubi_ainf_volume, rb);
+
+               if (be32_to_cpu(new_vh->vol_id) > tmp_av->vol_id)
+                       p = &(*p)->rb_left;
+               else if (be32_to_cpu(new_vh->vol_id) < tmp_av->vol_id)
+                       p = &(*p)->rb_right;
+               else {
+                       found = 1;
+                       break;
+               }
+       }
+
+       if (found)
+               av = tmp_av;
+       else {
+               ubi_err("orphaned volume in fastmap pool!");
+               return UBI_BAD_FASTMAP;
+       }
+
+       ubi_assert(be32_to_cpu(new_vh->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;
+
+       for (node = rb_first(&ai->volumes); node; node = rb_next(node)) {
+               av = rb_entry(node, struct ubi_ainf_volume, rb);
+
+               for (node2 = rb_first(&av->root); node2;
+                    node2 = rb_next(node2)) {
+                       aeb = rb_entry(node2, struct ubi_ainf_peb, u.rb);
+                       if (aeb->pnum == pnum) {
+                               rb_erase(&aeb->u.rb, &av->root);
+                               kmem_cache_free(ai->aeb_slab_cache, 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
+ * @eba_orphans: list of PEBs which need to be scanned
+ * @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,
+                    int *pebs, int pool_size, unsigned long long *max_sqnum,
+                    struct list_head *eba_orphans, struct list_head *free)
+{
+       struct ubi_vid_hdr *vh;
+       struct ubi_ec_hdr *ech;
+       struct ubi_ainf_peb *new_aeb, *tmp_aeb;
+       int i, pnum, err, found_orphan, ret = 0;
+
+       ech = kzalloc(ubi->ec_hdr_alsize, GFP_KERNEL);
+       if (!ech)
+               return -ENOMEM;
+
+       vh = ubi_zalloc_vid_hdr(ubi, GFP_KERNEL);
+       if (!vh) {
+               kfree(ech);
+               return -ENOMEM;
+       }
+
+       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;
+
+               pnum = be32_to_cpu(pebs[i]);
+
+               if (ubi_io_is_bad(ubi, pnum)) {
+                       ubi_err("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("unable to read EC header! PEB:%i err:%i",
+                               pnum, err);
+                       ret = err > 0 ? UBI_BAD_FASTMAP : err;
+                       goto out;
+               } else if (ret == UBI_IO_BITFLIPS)
+                       scrub = 1;
+
+               if (be32_to_cpu(ech->image_seq) != ubi->image_seq) {
+                       ubi_err("bad image seq: 0x%x, expected: 0x%x",
+                               be32_to_cpu(ech->image_seq), ubi->image_seq);
+                       err = UBI_BAD_FASTMAP;
+                       goto out;
+               }
+
+               err = ubi_io_read_vid_hdr(ubi, pnum, vh, 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)
+                               add_aeb(ai, free, pnum, ec, 1);
+                       else
+                               add_aeb(ai, free, pnum, ec, 0);
+                       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;
+
+                       found_orphan = 0;
+                       list_for_each_entry(tmp_aeb, eba_orphans, u.list) {
+                               if (tmp_aeb->pnum == pnum) {
+                                       found_orphan = 1;
+                                       break;
+                               }
+                       }
+                       if (found_orphan) {
+                               kmem_cache_free(ai->aeb_slab_cache, tmp_aeb);
+                               list_del(&tmp_aeb->u.list);
+                       }
+
+                       new_aeb = kmem_cache_alloc(ai->aeb_slab_cache,
+                                                  GFP_KERNEL);
+                       if (!new_aeb) {
+                               ret = -ENOMEM;
+                               goto out;
+                       }
+
+                       new_aeb->ec = be64_to_cpu(ech->ec);
+                       new_aeb->pnum = pnum;
+                       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("fastmap pool PEBs contains damaged PEBs!");
+                       ret = err > 0 ? UBI_BAD_FASTMAP : err;
+                       goto out;
+               }
+
+       }
+
+out:
+       ubi_free_vid_hdr(ubi, vh);
+       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, eba_orphans, free;
+       struct ubi_ainf_volume *av;
+       struct ubi_ainf_peb *aeb, *tmp_aeb, *_tmp_aeb;
+       struct ubi_ec_hdr *ech;
+       struct ubi_fm_sb *fmsb;
+       struct ubi_fm_hdr *fmhdr;
+       struct ubi_fm_scan_pool *fmpl1, *fmpl2;
+       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);
+       INIT_LIST_HEAD(&eba_orphans);
+       INIT_LIST_HEAD(&ai->corr);
+       INIT_LIST_HEAD(&ai->free);
+       INIT_LIST_HEAD(&ai->erase);
+       INIT_LIST_HEAD(&ai->alien);
+       ai->volumes = RB_ROOT;
+       ai->min_ec = UBI_MAX_ERASECOUNTER;
+
+       ai->aeb_slab_cache = kmem_cache_create("ubi_ainf_peb_slab",
+                                              sizeof(struct ubi_ainf_peb),
+                                              0, 0, NULL);
+       if (!ai->aeb_slab_cache) {
+               ret = -ENOMEM;
+               goto fail;
+       }
+
+       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("bad fastmap header magic: 0x%x, expected: 0x%x",
+                       be32_to_cpu(fmhdr->magic), UBI_FM_HDR_MAGIC);
+               goto fail_bad;
+       }
+
+       fmpl1 = (struct ubi_fm_scan_pool *)(fm_raw + fm_pos);
+       fm_pos += sizeof(*fmpl1);
+       if (fm_pos >= fm_size)
+               goto fail_bad;
+       if (be32_to_cpu(fmpl1->magic) != UBI_FM_POOL_MAGIC) {
+               ubi_err("bad fastmap pool magic: 0x%x, expected: 0x%x",
+                       be32_to_cpu(fmpl1->magic), UBI_FM_POOL_MAGIC);
+               goto fail_bad;
+       }
+
+       fmpl2 = (struct ubi_fm_scan_pool *)(fm_raw + fm_pos);
+       fm_pos += sizeof(*fmpl2);
+       if (fm_pos >= fm_size)
+               goto fail_bad;
+       if (be32_to_cpu(fmpl2->magic) != UBI_FM_POOL_MAGIC) {
+               ubi_err("bad fastmap pool magic: 0x%x, expected: 0x%x",
+                       be32_to_cpu(fmpl2->magic), UBI_FM_POOL_MAGIC);
+               goto fail_bad;
+       }
+
+       pool_size = be16_to_cpu(fmpl1->size);
+       wl_pool_size = be16_to_cpu(fmpl2->size);
+       fm->max_pool_size = be16_to_cpu(fmpl1->max_size);
+       fm->max_wl_pool_size = be16_to_cpu(fmpl2->max_size);
+
+       if (pool_size > UBI_FM_MAX_POOL_SIZE || pool_size < 0) {
+               ubi_err("bad pool size: %i", pool_size);
+               goto fail_bad;
+       }
+
+       if (wl_pool_size > UBI_FM_MAX_POOL_SIZE || wl_pool_size < 0) {
+               ubi_err("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("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("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;
+
+               add_aeb(ai, &ai->free, be32_to_cpu(fmec->pnum),
+                       be32_to_cpu(fmec->ec), 0);
+       }
+
+       /* 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;
+
+               add_aeb(ai, &used, be32_to_cpu(fmec->pnum),
+                       be32_to_cpu(fmec->ec), 0);
+       }
+
+       /* 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;
+
+               add_aeb(ai, &used, be32_to_cpu(fmec->pnum),
+                       be32_to_cpu(fmec->ec), 1);
+       }
+
+       /* 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;
+
+               add_aeb(ai, &ai->erase, be32_to_cpu(fmec->pnum),
+                       be32_to_cpu(fmec->ec), 1);
+       }
+
+       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("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 (!av)
+                       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("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 ((int)be32_to_cpu(fm_eba->pnum[j]) < 0)
+                               continue;
+
+                       aeb = NULL;
+                       list_for_each_entry(tmp_aeb, &used, u.list) {
+                               if (tmp_aeb->pnum == pnum)
+                                       aeb = tmp_aeb;
+                       }
+
+                       /* This can happen if a PEB is already in an EBA known
+                        * by this fastmap but the PEB itself is not in the used
+                        * list.
+                        * In this case the PEB can be within the fastmap pool
+                        * or while writing the fastmap it was in the protection
+                        * queue.
+                        */
+                       if (!aeb) {
+                               aeb = kmem_cache_alloc(ai->aeb_slab_cache,
+                                                      GFP_KERNEL);
+                               if (!aeb) {
+                                       ret = -ENOMEM;
+
+                                       goto fail;
+                               }
+
+                               aeb->lnum = j;
+                               aeb->pnum = be32_to_cpu(fm_eba->pnum[j]);
+                               aeb->ec = -1;
+                               aeb->scrub = aeb->copy_flag = aeb->sqnum = 0;
+                               list_add_tail(&aeb->u.list, &eba_orphans);
+                               continue;
+                       }
+
+                       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);
+               }
+
+               ech = kzalloc(ubi->ec_hdr_alsize, GFP_KERNEL);
+               if (!ech) {
+                       ret = -ENOMEM;
+                       goto fail;
+               }
+
+               list_for_each_entry_safe(tmp_aeb, _tmp_aeb, &eba_orphans,
+                                        u.list) {
+                       int err;
+
+                       if (ubi_io_is_bad(ubi, tmp_aeb->pnum)) {
+                               ubi_err("bad PEB in fastmap EBA orphan list");
+                               ret = UBI_BAD_FASTMAP;
+                               kfree(ech);
+                               goto fail;
+                       }
+
+                       err = ubi_io_read_ec_hdr(ubi, tmp_aeb->pnum, ech, 0);
+                       if (err && err != UBI_IO_BITFLIPS) {
+                               ubi_err("unable to read EC header! PEB:%i " \
+                                       "err:%i", tmp_aeb->pnum, err);
+                               ret = err > 0 ? UBI_BAD_FASTMAP : err;
+                               kfree(ech);
+
+                               goto fail;
+                       } else if (err == UBI_IO_BITFLIPS)
+                               tmp_aeb->scrub = 1;
+
+                       tmp_aeb->ec = be64_to_cpu(ech->ec);
+                       assign_aeb_to_av(ai, tmp_aeb, av);
+               }
+
+               kfree(ech);
+       }
+
+       ret = scan_pool(ubi, ai, fmpl1->pebs, pool_size, &max_sqnum,
+                       &eba_orphans, &free);
+       if (ret)
+               goto fail;
+
+       ret = scan_pool(ubi, ai, fmpl2->pebs, wl_pool_size, &max_sqnum,
+                       &eba_orphans, &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_del(&tmp_aeb->u.list);
+               list_add_tail(&tmp_aeb->u.list, &ai->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:
+       return ret;
+}
+
+/**
+ * ubi_scan_fastmap - scan the fastmap.
+ * @ubi: UBI device object
+ * @ai: UBI attach info to be filled
+ * @fm_anchor: The fastmap starts at this PEB
+ *
+ * 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,
+                    int fm_anchor)
+{
+       struct ubi_fm_sb *fmsb, *fmsb2;
+       struct ubi_vid_hdr *vh;
+       struct ubi_ec_hdr *ech;
+       struct ubi_fastmap_layout *fm;
+       int i, used_blocks, pnum, ret = 0;
+       size_t fm_size;
+       __be32 crc, tmp_crc;
+       unsigned long long sqnum = 0;
+
+       mutex_lock(&ubi->fm_mutex);
+       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(ubi, fmsb, fm_anchor, ubi->leb_start, 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("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("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("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("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;
+       }
+
+       vh = ubi_zalloc_vid_hdr(ubi, GFP_KERNEL);
+       if (!vh) {
+               ret = -ENOMEM;
+               goto free_hdr;
+       }
+
+       for (i = 0; i < used_blocks; i++) {
+               pnum = be32_to_cpu(fmsb->block_loc[i]);
+
+               if (ubi_io_is_bad(ubi, pnum)) {
+                       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("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;
+
+               if (!ubi->image_seq)
+                       ubi->image_seq = be32_to_cpu(ech->image_seq);
+
+               if (be32_to_cpu(ech->image_seq) != ubi->image_seq) {
+                       ret = UBI_BAD_FASTMAP;
+                       goto free_hdr;
+               }
+
+               ret = ubi_io_read_vid_hdr(ubi, pnum, vh, 0);
+               if (ret && ret != UBI_IO_BITFLIPS) {
+                       ubi_err("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("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("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(ubi, ubi->fm_buf + (ubi->leb_size * i), pnum,
+                                 ubi->leb_start, ubi->leb_size);
+               if (ret && ret != UBI_IO_BITFLIPS) {
+                       ubi_err("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("fastmap data CRC is invalid");
+               ubi_err("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--)
+                               kfree(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("attached by fastmap");
+       ubi_msg("fastmap pool size: %d", ubi->fm_pool.max_size);
+       ubi_msg("fastmap WL pool size: %d", ubi->fm_wl_pool.max_size);
+       ubi->fm_disabled = 0;
+
+       ubi_free_vid_hdr(ubi, vh);
+       kfree(ech);
+out:
+       mutex_unlock(&ubi->fm_mutex);
+       if (ret == UBI_BAD_FASTMAP)
+               ubi_err("Attach by fastmap failed, doing a full scan!");
+       return ret;
+
+free_hdr:
+       ubi_free_vid_hdr(ubi, vh);
+       kfree(ech);
+free_fm_sb:
+       kfree(fmsb);
+       kfree(fm);
+       goto out;
+}
+
+/**
+ * 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 *fmpl1, *fmpl2;
+       struct ubi_fm_ec *fec;
+       struct ubi_fm_volhdr *fvh;
+       struct ubi_fm_eba *feba;
+       struct rb_node *node;
+       struct ubi_wl_entry *wl_e;
+       struct ubi_volume *vol;
+       struct ubi_vid_hdr *avhdr, *dvhdr;
+       struct ubi_work *ubi_wrk;
+       int ret, i, j, free_peb_count, used_peb_count, vol_count;
+       int scrub_peb_count, erase_peb_count;
+
+       fm_raw = ubi->fm_buf;
+       memset(ubi->fm_buf, 0, ubi->fm_size);
+
+       avhdr = new_fm_vhdr(ubi, UBI_FM_SB_VOLUME_ID);
+       if (!avhdr) {
+               ret = -ENOMEM;
+               goto out;
+       }
+
+       dvhdr = new_fm_vhdr(ubi, UBI_FM_DATA_VOLUME_ID);
+       if (!dvhdr) {
+               ret = -ENOMEM;
+               goto out_kfree;
+       }
+
+       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;
+
+       fmpl1 = (struct ubi_fm_scan_pool *)(fm_raw + fm_pos);
+       fm_pos += sizeof(*fmpl1);
+       fmpl1->magic = cpu_to_be32(UBI_FM_POOL_MAGIC);
+       fmpl1->size = cpu_to_be16(ubi->fm_pool.size);
+       fmpl1->max_size = cpu_to_be16(ubi->fm_pool.max_size);
+
+       for (i = 0; i < ubi->fm_pool.size; i++)
+               fmpl1->pebs[i] = cpu_to_be32(ubi->fm_pool.pebs[i]);
+
+       fmpl2 = (struct ubi_fm_scan_pool *)(fm_raw + fm_pos);
+       fm_pos += sizeof(*fmpl2);
+       fmpl2->magic = cpu_to_be32(UBI_FM_POOL_MAGIC);
+       fmpl2->size = cpu_to_be16(ubi->fm_wl_pool.size);
+       fmpl2->max_size = cpu_to_be16(ubi->fm_wl_pool.max_size);
+
+       for (i = 0; i < ubi->fm_wl_pool.size; i++)
+               fmpl2->pebs[i] = cpu_to_be32(ubi->fm_wl_pool.pebs[i]);
+
+       for (node = rb_first(&ubi->free); node; node = rb_next(node)) {
+               wl_e = rb_entry(node, struct ubi_wl_entry, u.rb);
+               fec = (struct ubi_fm_ec *)(fm_raw + fm_pos);
+
+               fec->pnum = cpu_to_be32(wl_e->pnum);
+               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);
+
+       for (node = rb_first(&ubi->used); node; node = rb_next(node)) {
+               wl_e = rb_entry(node, struct ubi_wl_entry, u.rb);
+               fec = (struct ubi_fm_ec *)(fm_raw + fm_pos);
+
+               fec->pnum = cpu_to_be32(wl_e->pnum);
+               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);
+
+       for (node = rb_first(&ubi->scrub); node; node = rb_next(node)) {
+               wl_e = rb_entry(node, struct ubi_wl_entry, u.rb);
+               fec = (struct ubi_fm_ec *)(fm_raw + fm_pos);
+
+               fec->pnum = cpu_to_be32(wl_e->pnum);
+               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);
+                       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++)
+                       feba->pnum[j] = cpu_to_be32(vol->eba_tbl[j]);
+
+               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, avhdr);
+       if (ret) {
+               ubi_err("unable to write vid_hdr to fastmap SB!");
+               goto out_kfree;
+       }
+
+       for (i = 0; i < new_fm->used_blocks; i++) {
+               fmsb->block_loc[i] = cpu_to_be32(new_fm->e[i]->pnum);
+               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, dvhdr);
+               if (ret) {
+                       ubi_err("unable to write vid_hdr to PEB %i!",
+                               new_fm->e[i]->pnum);
+                       goto out_kfree;
+               }
+       }
+
+       for (i = 0; i < new_fm->used_blocks; i++) {
+               ret = ubi_io_write(ubi, fm_raw + (i * ubi->leb_size),
+                       new_fm->e[i]->pnum, ubi->leb_start, ubi->leb_size);
+               if (ret) {
+                       ubi_err("unable to write fastmap to PEB %i!",
+                               new_fm->e[i]->pnum);
+                       goto out_kfree;
+               }
+       }
+
+       ubi_assert(new_fm);
+       ubi->fm = new_fm;
+
+       dbg_bld("fastmap written!");
+
+out_kfree:
+       ubi_free_vid_hdr(ubi, avhdr);
+       ubi_free_vid_hdr(ubi, dvhdr);
+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
+ * @fm: the fastmap to be destroyed
+ *
+ * Returns 0 on success, < 0 indicates an internal error.
+ */
+static int invalidate_fastmap(struct ubi_device *ubi,
+                             struct ubi_fastmap_layout *fm)
+{
+       int ret, i;
+       struct ubi_vid_hdr *vh;
+
+       ret = erase_block(ubi, fm->e[0]->pnum);
+       if (ret < 0)
+               return ret;
+
+       vh = new_fm_vhdr(ubi, UBI_FM_SB_VOLUME_ID);
+       if (!vh)
+               return -ENOMEM;
+
+       /* deleting the current fastmap SB is not enough, an old SB may exist,
+        * so create a (corrupted) SB such that fastmap will find it and fall
+        * back to scanning mode in any case */
+       vh->sqnum = cpu_to_be64(ubi_next_sqnum(ubi));
+       ret = ubi_io_write_vid_hdr(ubi, fm->e[0]->pnum, vh);
+
+       for (i = 0; i < fm->used_blocks; i++)
+               ubi_wl_put_fm_peb(ubi, fm->e[i], i, fm->to_be_tortured[i]);
+
+       return ret;
+}
+
+/**
+ * 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;
+       struct ubi_fastmap_layout *new_fm, *old_fm;
+       struct ubi_wl_entry *tmp_e;
+
+       mutex_lock(&ubi->fm_mutex);
+
+       ubi_refill_pools(ubi);
+
+       if (ubi->ro_mode || ubi->fm_disabled) {
+               mutex_unlock(&ubi->fm_mutex);
+               return 0;
+       }
+
+       ret = ubi_ensure_anchor_pebs(ubi);
+       if (ret) {
+               mutex_unlock(&ubi->fm_mutex);
+               return ret;
+       }
+
+       new_fm = kzalloc(sizeof(*new_fm), GFP_KERNEL);
+       if (!new_fm) {
+               mutex_unlock(&ubi->fm_mutex);
+               return -ENOMEM;
+       }
+
+       new_fm->used_blocks = ubi->fm_size / ubi->leb_size;
+
+       for (i = 0; i < new_fm->used_blocks; i++) {
+               new_fm->e[i] = kmem_cache_alloc(ubi_wl_entry_slab, GFP_KERNEL);
+               if (!new_fm->e[i]) {
+                       while (i--)
+                               kfree(new_fm->e[i]);
+
+                       kfree(new_fm);
+                       mutex_unlock(&ubi->fm_mutex);
+                       return -ENOMEM;
+               }
+       }
+
+       old_fm = ubi->fm;
+       ubi->fm = NULL;
+
+       if (new_fm->used_blocks > UBI_FM_MAX_BLOCKS) {
+               ubi_err("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 && !old_fm) {
+                       int j;
+                       ubi_err("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);
+
+                       ret = -ENOSPC;
+                       goto err;
+               } else if (!tmp_e && old_fm) {
+                       ret = erase_block(ubi, old_fm->e[i]->pnum);
+                       if (ret < 0) {
+                               int j;
+
+                               for (j = 1; j < i; j++)
+                                       ubi_wl_put_fm_peb(ubi, new_fm->e[j],
+                                                         j, 0);
+
+                               ubi_err("could not erase old fastmap PEB");
+                               goto err;
+                       }
+
+                       new_fm->e[i]->pnum = old_fm->e[i]->pnum;
+                       new_fm->e[i]->ec = old_fm->e[i]->ec;
+               } else {
+                       new_fm->e[i]->pnum = tmp_e->pnum;
+                       new_fm->e[i]->ec = tmp_e->ec;
+
+                       if (old_fm)
+                               ubi_wl_put_fm_peb(ubi, old_fm->e[i], i,
+                                                 old_fm->to_be_tortured[i]);
+               }
+       }
+
+       spin_lock(&ubi->wl_lock);
+       tmp_e = ubi_wl_get_fm_peb(ubi, 1);
+       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) {
+                               int i;
+                               ubi_err("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);
+                               goto err;
+                       }
+
+                       new_fm->e[0]->pnum = old_fm->e[0]->pnum;
+                       new_fm->e[0]->ec = ret;
+               } 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]->pnum = tmp_e->pnum;
+                       new_fm->e[0]->ec = tmp_e->ec;
+               }
+       } else {
+               if (!tmp_e) {
+                       int i;
+                       ubi_err("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);
+
+                       ret = -ENOSPC;
+                       goto err;
+               }
+
+               new_fm->e[0]->pnum = tmp_e->pnum;
+               new_fm->e[0]->ec = tmp_e->ec;
+       }
+
+       down_write(&ubi->work_sem);
+       down_write(&ubi->fm_sem);
+       ret = ubi_write_fastmap(ubi, new_fm);
+       up_write(&ubi->fm_sem);
+       up_write(&ubi->work_sem);
+
+       if (ret)
+               goto err;
+
+out_unlock:
+       mutex_unlock(&ubi->fm_mutex);
+       kfree(old_fm);
+       return ret;
+
+err:
+       kfree(new_fm);
+
+       ubi_warn("Unable to write new fastmap, err=%i", ret);
+
+       ret = 0;
+       if (old_fm) {
+               ret = invalidate_fastmap(ubi, old_fm);
+               if (ret < 0)
+                       ubi_err("Unable to invalidiate current fastmap!");
+               else if (ret)
+                       ret = 0;
+       }
+       goto out_unlock;
+}