Add the rt linux 4.1.3-rt3 as base
[kvmfornfv.git] / kernel / drivers / mtd / ubi / eba.c
diff --git a/kernel/drivers/mtd/ubi/eba.c b/kernel/drivers/mtd/ubi/eba.c
new file mode 100644 (file)
index 0000000..51bca03
--- /dev/null
@@ -0,0 +1,1477 @@
+/*
+ * Copyright (c) International Business Machines Corp., 2006
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
+ * the GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ *
+ * Author: Artem Bityutskiy (Битюцкий Артём)
+ */
+
+/*
+ * The UBI Eraseblock Association (EBA) sub-system.
+ *
+ * This sub-system is responsible for I/O to/from logical eraseblock.
+ *
+ * Although in this implementation the EBA table is fully kept and managed in
+ * RAM, which assumes poor scalability, it might be (partially) maintained on
+ * flash in future implementations.
+ *
+ * The EBA sub-system implements per-logical eraseblock locking. Before
+ * accessing a logical eraseblock it is locked for reading or writing. The
+ * per-logical eraseblock locking is implemented by means of the lock tree. The
+ * lock tree is an RB-tree which refers all the currently locked logical
+ * eraseblocks. The lock tree elements are &struct ubi_ltree_entry objects.
+ * They are indexed by (@vol_id, @lnum) pairs.
+ *
+ * EBA also maintains the global sequence counter which is incremented each
+ * time a logical eraseblock is mapped to a physical eraseblock and it is
+ * stored in the volume identifier header. This means that each VID header has
+ * a unique sequence number. The sequence number is only increased an we assume
+ * 64 bits is enough to never overflow.
+ */
+
+#include <linux/slab.h>
+#include <linux/crc32.h>
+#include <linux/err.h>
+#include "ubi.h"
+
+/* Number of physical eraseblocks reserved for atomic LEB change operation */
+#define EBA_RESERVED_PEBS 1
+
+/**
+ * next_sqnum - get next sequence number.
+ * @ubi: UBI device description object
+ *
+ * This function returns next sequence number to use, which is just the current
+ * global sequence counter value. It also increases the global sequence
+ * counter.
+ */
+unsigned long long ubi_next_sqnum(struct ubi_device *ubi)
+{
+       unsigned long long sqnum;
+
+       spin_lock(&ubi->ltree_lock);
+       sqnum = ubi->global_sqnum++;
+       spin_unlock(&ubi->ltree_lock);
+
+       return sqnum;
+}
+
+/**
+ * ubi_get_compat - get compatibility flags of a volume.
+ * @ubi: UBI device description object
+ * @vol_id: volume ID
+ *
+ * This function returns compatibility flags for an internal volume. User
+ * volumes have no compatibility flags, so %0 is returned.
+ */
+static int ubi_get_compat(const struct ubi_device *ubi, int vol_id)
+{
+       if (vol_id == UBI_LAYOUT_VOLUME_ID)
+               return UBI_LAYOUT_VOLUME_COMPAT;
+       return 0;
+}
+
+/**
+ * ltree_lookup - look up the lock tree.
+ * @ubi: UBI device description object
+ * @vol_id: volume ID
+ * @lnum: logical eraseblock number
+ *
+ * This function returns a pointer to the corresponding &struct ubi_ltree_entry
+ * object if the logical eraseblock is locked and %NULL if it is not.
+ * @ubi->ltree_lock has to be locked.
+ */
+static struct ubi_ltree_entry *ltree_lookup(struct ubi_device *ubi, int vol_id,
+                                           int lnum)
+{
+       struct rb_node *p;
+
+       p = ubi->ltree.rb_node;
+       while (p) {
+               struct ubi_ltree_entry *le;
+
+               le = rb_entry(p, struct ubi_ltree_entry, rb);
+
+               if (vol_id < le->vol_id)
+                       p = p->rb_left;
+               else if (vol_id > le->vol_id)
+                       p = p->rb_right;
+               else {
+                       if (lnum < le->lnum)
+                               p = p->rb_left;
+                       else if (lnum > le->lnum)
+                               p = p->rb_right;
+                       else
+                               return le;
+               }
+       }
+
+       return NULL;
+}
+
+/**
+ * ltree_add_entry - add new entry to the lock tree.
+ * @ubi: UBI device description object
+ * @vol_id: volume ID
+ * @lnum: logical eraseblock number
+ *
+ * This function adds new entry for logical eraseblock (@vol_id, @lnum) to the
+ * lock tree. If such entry is already there, its usage counter is increased.
+ * Returns pointer to the lock tree entry or %-ENOMEM if memory allocation
+ * failed.
+ */
+static struct ubi_ltree_entry *ltree_add_entry(struct ubi_device *ubi,
+                                              int vol_id, int lnum)
+{
+       struct ubi_ltree_entry *le, *le1, *le_free;
+
+       le = kmalloc(sizeof(struct ubi_ltree_entry), GFP_NOFS);
+       if (!le)
+               return ERR_PTR(-ENOMEM);
+
+       le->users = 0;
+       init_rwsem(&le->mutex);
+       le->vol_id = vol_id;
+       le->lnum = lnum;
+
+       spin_lock(&ubi->ltree_lock);
+       le1 = ltree_lookup(ubi, vol_id, lnum);
+
+       if (le1) {
+               /*
+                * This logical eraseblock is already locked. The newly
+                * allocated lock entry is not needed.
+                */
+               le_free = le;
+               le = le1;
+       } else {
+               struct rb_node **p, *parent = NULL;
+
+               /*
+                * No lock entry, add the newly allocated one to the
+                * @ubi->ltree RB-tree.
+                */
+               le_free = NULL;
+
+               p = &ubi->ltree.rb_node;
+               while (*p) {
+                       parent = *p;
+                       le1 = rb_entry(parent, struct ubi_ltree_entry, rb);
+
+                       if (vol_id < le1->vol_id)
+                               p = &(*p)->rb_left;
+                       else if (vol_id > le1->vol_id)
+                               p = &(*p)->rb_right;
+                       else {
+                               ubi_assert(lnum != le1->lnum);
+                               if (lnum < le1->lnum)
+                                       p = &(*p)->rb_left;
+                               else
+                                       p = &(*p)->rb_right;
+                       }
+               }
+
+               rb_link_node(&le->rb, parent, p);
+               rb_insert_color(&le->rb, &ubi->ltree);
+       }
+       le->users += 1;
+       spin_unlock(&ubi->ltree_lock);
+
+       kfree(le_free);
+       return le;
+}
+
+/**
+ * leb_read_lock - lock logical eraseblock for reading.
+ * @ubi: UBI device description object
+ * @vol_id: volume ID
+ * @lnum: logical eraseblock number
+ *
+ * This function locks a logical eraseblock for reading. Returns zero in case
+ * of success and a negative error code in case of failure.
+ */
+static int leb_read_lock(struct ubi_device *ubi, int vol_id, int lnum)
+{
+       struct ubi_ltree_entry *le;
+
+       le = ltree_add_entry(ubi, vol_id, lnum);
+       if (IS_ERR(le))
+               return PTR_ERR(le);
+       down_read(&le->mutex);
+       return 0;
+}
+
+/**
+ * leb_read_unlock - unlock logical eraseblock.
+ * @ubi: UBI device description object
+ * @vol_id: volume ID
+ * @lnum: logical eraseblock number
+ */
+static void leb_read_unlock(struct ubi_device *ubi, int vol_id, int lnum)
+{
+       struct ubi_ltree_entry *le;
+
+       spin_lock(&ubi->ltree_lock);
+       le = ltree_lookup(ubi, vol_id, lnum);
+       le->users -= 1;
+       ubi_assert(le->users >= 0);
+       up_read(&le->mutex);
+       if (le->users == 0) {
+               rb_erase(&le->rb, &ubi->ltree);
+               kfree(le);
+       }
+       spin_unlock(&ubi->ltree_lock);
+}
+
+/**
+ * leb_write_lock - lock logical eraseblock for writing.
+ * @ubi: UBI device description object
+ * @vol_id: volume ID
+ * @lnum: logical eraseblock number
+ *
+ * This function locks a logical eraseblock for writing. Returns zero in case
+ * of success and a negative error code in case of failure.
+ */
+static int leb_write_lock(struct ubi_device *ubi, int vol_id, int lnum)
+{
+       struct ubi_ltree_entry *le;
+
+       le = ltree_add_entry(ubi, vol_id, lnum);
+       if (IS_ERR(le))
+               return PTR_ERR(le);
+       down_write(&le->mutex);
+       return 0;
+}
+
+/**
+ * leb_write_lock - lock logical eraseblock for writing.
+ * @ubi: UBI device description object
+ * @vol_id: volume ID
+ * @lnum: logical eraseblock number
+ *
+ * This function locks a logical eraseblock for writing if there is no
+ * contention and does nothing if there is contention. Returns %0 in case of
+ * success, %1 in case of contention, and and a negative error code in case of
+ * failure.
+ */
+static int leb_write_trylock(struct ubi_device *ubi, int vol_id, int lnum)
+{
+       struct ubi_ltree_entry *le;
+
+       le = ltree_add_entry(ubi, vol_id, lnum);
+       if (IS_ERR(le))
+               return PTR_ERR(le);
+       if (down_write_trylock(&le->mutex))
+               return 0;
+
+       /* Contention, cancel */
+       spin_lock(&ubi->ltree_lock);
+       le->users -= 1;
+       ubi_assert(le->users >= 0);
+       if (le->users == 0) {
+               rb_erase(&le->rb, &ubi->ltree);
+               kfree(le);
+       }
+       spin_unlock(&ubi->ltree_lock);
+
+       return 1;
+}
+
+/**
+ * leb_write_unlock - unlock logical eraseblock.
+ * @ubi: UBI device description object
+ * @vol_id: volume ID
+ * @lnum: logical eraseblock number
+ */
+static void leb_write_unlock(struct ubi_device *ubi, int vol_id, int lnum)
+{
+       struct ubi_ltree_entry *le;
+
+       spin_lock(&ubi->ltree_lock);
+       le = ltree_lookup(ubi, vol_id, lnum);
+       le->users -= 1;
+       ubi_assert(le->users >= 0);
+       up_write(&le->mutex);
+       if (le->users == 0) {
+               rb_erase(&le->rb, &ubi->ltree);
+               kfree(le);
+       }
+       spin_unlock(&ubi->ltree_lock);
+}
+
+/**
+ * ubi_eba_unmap_leb - un-map logical eraseblock.
+ * @ubi: UBI device description object
+ * @vol: volume description object
+ * @lnum: logical eraseblock number
+ *
+ * This function un-maps logical eraseblock @lnum and schedules corresponding
+ * physical eraseblock for erasure. Returns zero in case of success and a
+ * negative error code in case of failure.
+ */
+int ubi_eba_unmap_leb(struct ubi_device *ubi, struct ubi_volume *vol,
+                     int lnum)
+{
+       int err, pnum, vol_id = vol->vol_id;
+
+       if (ubi->ro_mode)
+               return -EROFS;
+
+       err = leb_write_lock(ubi, vol_id, lnum);
+       if (err)
+               return err;
+
+       pnum = vol->eba_tbl[lnum];
+       if (pnum < 0)
+               /* This logical eraseblock is already unmapped */
+               goto out_unlock;
+
+       dbg_eba("erase LEB %d:%d, PEB %d", vol_id, lnum, pnum);
+
+       down_read(&ubi->fm_eba_sem);
+       vol->eba_tbl[lnum] = UBI_LEB_UNMAPPED;
+       up_read(&ubi->fm_eba_sem);
+       err = ubi_wl_put_peb(ubi, vol_id, lnum, pnum, 0);
+
+out_unlock:
+       leb_write_unlock(ubi, vol_id, lnum);
+       return err;
+}
+
+/**
+ * ubi_eba_read_leb - read data.
+ * @ubi: UBI device description object
+ * @vol: volume description object
+ * @lnum: logical eraseblock number
+ * @buf: buffer to store the read data
+ * @offset: offset from where to read
+ * @len: how many bytes to read
+ * @check: data CRC check flag
+ *
+ * If the logical eraseblock @lnum is unmapped, @buf is filled with 0xFF
+ * bytes. The @check flag only makes sense for static volumes and forces
+ * eraseblock data CRC checking.
+ *
+ * In case of success this function returns zero. In case of a static volume,
+ * if data CRC mismatches - %-EBADMSG is returned. %-EBADMSG may also be
+ * returned for any volume type if an ECC error was detected by the MTD device
+ * driver. Other negative error cored may be returned in case of other errors.
+ */
+int ubi_eba_read_leb(struct ubi_device *ubi, struct ubi_volume *vol, int lnum,
+                    void *buf, int offset, int len, int check)
+{
+       int err, pnum, scrub = 0, vol_id = vol->vol_id;
+       struct ubi_vid_hdr *vid_hdr;
+       uint32_t uninitialized_var(crc);
+
+       err = leb_read_lock(ubi, vol_id, lnum);
+       if (err)
+               return err;
+
+       pnum = vol->eba_tbl[lnum];
+       if (pnum < 0) {
+               /*
+                * The logical eraseblock is not mapped, fill the whole buffer
+                * with 0xFF bytes. The exception is static volumes for which
+                * it is an error to read unmapped logical eraseblocks.
+                */
+               dbg_eba("read %d bytes from offset %d of LEB %d:%d (unmapped)",
+                       len, offset, vol_id, lnum);
+               leb_read_unlock(ubi, vol_id, lnum);
+               ubi_assert(vol->vol_type != UBI_STATIC_VOLUME);
+               memset(buf, 0xFF, len);
+               return 0;
+       }
+
+       dbg_eba("read %d bytes from offset %d of LEB %d:%d, PEB %d",
+               len, offset, vol_id, lnum, pnum);
+
+       if (vol->vol_type == UBI_DYNAMIC_VOLUME)
+               check = 0;
+
+retry:
+       if (check) {
+               vid_hdr = ubi_zalloc_vid_hdr(ubi, GFP_NOFS);
+               if (!vid_hdr) {
+                       err = -ENOMEM;
+                       goto out_unlock;
+               }
+
+               err = ubi_io_read_vid_hdr(ubi, pnum, vid_hdr, 1);
+               if (err && err != UBI_IO_BITFLIPS) {
+                       if (err > 0) {
+                               /*
+                                * The header is either absent or corrupted.
+                                * The former case means there is a bug -
+                                * switch to read-only mode just in case.
+                                * The latter case means a real corruption - we
+                                * may try to recover data. FIXME: but this is
+                                * not implemented.
+                                */
+                               if (err == UBI_IO_BAD_HDR_EBADMSG ||
+                                   err == UBI_IO_BAD_HDR) {
+                                       ubi_warn(ubi, "corrupted VID header at PEB %d, LEB %d:%d",
+                                                pnum, vol_id, lnum);
+                                       err = -EBADMSG;
+                               } else {
+                                       err = -EINVAL;
+                                       ubi_ro_mode(ubi);
+                               }
+                       }
+                       goto out_free;
+               } else if (err == UBI_IO_BITFLIPS)
+                       scrub = 1;
+
+               ubi_assert(lnum < be32_to_cpu(vid_hdr->used_ebs));
+               ubi_assert(len == be32_to_cpu(vid_hdr->data_size));
+
+               crc = be32_to_cpu(vid_hdr->data_crc);
+               ubi_free_vid_hdr(ubi, vid_hdr);
+       }
+
+       err = ubi_io_read_data(ubi, buf, pnum, offset, len);
+       if (err) {
+               if (err == UBI_IO_BITFLIPS)
+                       scrub = 1;
+               else if (mtd_is_eccerr(err)) {
+                       if (vol->vol_type == UBI_DYNAMIC_VOLUME)
+                               goto out_unlock;
+                       scrub = 1;
+                       if (!check) {
+                               ubi_msg(ubi, "force data checking");
+                               check = 1;
+                               goto retry;
+                       }
+               } else
+                       goto out_unlock;
+       }
+
+       if (check) {
+               uint32_t crc1 = crc32(UBI_CRC32_INIT, buf, len);
+               if (crc1 != crc) {
+                       ubi_warn(ubi, "CRC error: calculated %#08x, must be %#08x",
+                                crc1, crc);
+                       err = -EBADMSG;
+                       goto out_unlock;
+               }
+       }
+
+       if (scrub)
+               err = ubi_wl_scrub_peb(ubi, pnum);
+
+       leb_read_unlock(ubi, vol_id, lnum);
+       return err;
+
+out_free:
+       ubi_free_vid_hdr(ubi, vid_hdr);
+out_unlock:
+       leb_read_unlock(ubi, vol_id, lnum);
+       return err;
+}
+
+/**
+ * ubi_eba_read_leb_sg - read data into a scatter gather list.
+ * @ubi: UBI device description object
+ * @vol: volume description object
+ * @lnum: logical eraseblock number
+ * @sgl: UBI scatter gather list to store the read data
+ * @offset: offset from where to read
+ * @len: how many bytes to read
+ * @check: data CRC check flag
+ *
+ * This function works exactly like ubi_eba_read_leb(). But instead of
+ * storing the read data into a buffer it writes to an UBI scatter gather
+ * list.
+ */
+int ubi_eba_read_leb_sg(struct ubi_device *ubi, struct ubi_volume *vol,
+                       struct ubi_sgl *sgl, int lnum, int offset, int len,
+                       int check)
+{
+       int to_read;
+       int ret;
+       struct scatterlist *sg;
+
+       for (;;) {
+               ubi_assert(sgl->list_pos < UBI_MAX_SG_COUNT);
+               sg = &sgl->sg[sgl->list_pos];
+               if (len < sg->length - sgl->page_pos)
+                       to_read = len;
+               else
+                       to_read = sg->length - sgl->page_pos;
+
+               ret = ubi_eba_read_leb(ubi, vol, lnum,
+                                      sg_virt(sg) + sgl->page_pos, offset,
+                                      to_read, check);
+               if (ret < 0)
+                       return ret;
+
+               offset += to_read;
+               len -= to_read;
+               if (!len) {
+                       sgl->page_pos += to_read;
+                       if (sgl->page_pos == sg->length) {
+                               sgl->list_pos++;
+                               sgl->page_pos = 0;
+                       }
+
+                       break;
+               }
+
+               sgl->list_pos++;
+               sgl->page_pos = 0;
+       }
+
+       return ret;
+}
+
+/**
+ * recover_peb - recover from write failure.
+ * @ubi: UBI device description object
+ * @pnum: the physical eraseblock to recover
+ * @vol_id: volume ID
+ * @lnum: logical eraseblock number
+ * @buf: data which was not written because of the write failure
+ * @offset: offset of the failed write
+ * @len: how many bytes should have been written
+ *
+ * This function is called in case of a write failure and moves all good data
+ * from the potentially bad physical eraseblock to a good physical eraseblock.
+ * This function also writes the data which was not written due to the failure.
+ * Returns new physical eraseblock number in case of success, and a negative
+ * error code in case of failure.
+ */
+static int recover_peb(struct ubi_device *ubi, int pnum, int vol_id, int lnum,
+                      const void *buf, int offset, int len)
+{
+       int err, idx = vol_id2idx(ubi, vol_id), new_pnum, data_size, tries = 0;
+       struct ubi_volume *vol = ubi->volumes[idx];
+       struct ubi_vid_hdr *vid_hdr;
+
+       vid_hdr = ubi_zalloc_vid_hdr(ubi, GFP_NOFS);
+       if (!vid_hdr)
+               return -ENOMEM;
+
+retry:
+       new_pnum = ubi_wl_get_peb(ubi);
+       if (new_pnum < 0) {
+               ubi_free_vid_hdr(ubi, vid_hdr);
+               up_read(&ubi->fm_eba_sem);
+               return new_pnum;
+       }
+
+       ubi_msg(ubi, "recover PEB %d, move data to PEB %d",
+               pnum, new_pnum);
+
+       err = ubi_io_read_vid_hdr(ubi, pnum, vid_hdr, 1);
+       if (err && err != UBI_IO_BITFLIPS) {
+               if (err > 0)
+                       err = -EIO;
+               up_read(&ubi->fm_eba_sem);
+               goto out_put;
+       }
+
+       vid_hdr->sqnum = cpu_to_be64(ubi_next_sqnum(ubi));
+       err = ubi_io_write_vid_hdr(ubi, new_pnum, vid_hdr);
+       if (err) {
+               up_read(&ubi->fm_eba_sem);
+               goto write_error;
+       }
+
+       data_size = offset + len;
+       mutex_lock(&ubi->buf_mutex);
+       memset(ubi->peb_buf + offset, 0xFF, len);
+
+       /* Read everything before the area where the write failure happened */
+       if (offset > 0) {
+               err = ubi_io_read_data(ubi, ubi->peb_buf, pnum, 0, offset);
+               if (err && err != UBI_IO_BITFLIPS) {
+                       up_read(&ubi->fm_eba_sem);
+                       goto out_unlock;
+               }
+       }
+
+       memcpy(ubi->peb_buf + offset, buf, len);
+
+       err = ubi_io_write_data(ubi, ubi->peb_buf, new_pnum, 0, data_size);
+       if (err) {
+               mutex_unlock(&ubi->buf_mutex);
+               up_read(&ubi->fm_eba_sem);
+               goto write_error;
+       }
+
+       mutex_unlock(&ubi->buf_mutex);
+       ubi_free_vid_hdr(ubi, vid_hdr);
+
+       vol->eba_tbl[lnum] = new_pnum;
+       up_read(&ubi->fm_eba_sem);
+       ubi_wl_put_peb(ubi, vol_id, lnum, pnum, 1);
+
+       ubi_msg(ubi, "data was successfully recovered");
+       return 0;
+
+out_unlock:
+       mutex_unlock(&ubi->buf_mutex);
+out_put:
+       ubi_wl_put_peb(ubi, vol_id, lnum, new_pnum, 1);
+       ubi_free_vid_hdr(ubi, vid_hdr);
+       return err;
+
+write_error:
+       /*
+        * Bad luck? This physical eraseblock is bad too? Crud. Let's try to
+        * get another one.
+        */
+       ubi_warn(ubi, "failed to write to PEB %d", new_pnum);
+       ubi_wl_put_peb(ubi, vol_id, lnum, new_pnum, 1);
+       if (++tries > UBI_IO_RETRIES) {
+               ubi_free_vid_hdr(ubi, vid_hdr);
+               return err;
+       }
+       ubi_msg(ubi, "try again");
+       goto retry;
+}
+
+/**
+ * ubi_eba_write_leb - write data to dynamic volume.
+ * @ubi: UBI device description object
+ * @vol: volume description object
+ * @lnum: logical eraseblock number
+ * @buf: the data to write
+ * @offset: offset within the logical eraseblock where to write
+ * @len: how many bytes to write
+ *
+ * This function writes data to logical eraseblock @lnum of a dynamic volume
+ * @vol. Returns zero in case of success and a negative error code in case
+ * of failure. In case of error, it is possible that something was still
+ * written to the flash media, but may be some garbage.
+ */
+int ubi_eba_write_leb(struct ubi_device *ubi, struct ubi_volume *vol, int lnum,
+                     const void *buf, int offset, int len)
+{
+       int err, pnum, tries = 0, vol_id = vol->vol_id;
+       struct ubi_vid_hdr *vid_hdr;
+
+       if (ubi->ro_mode)
+               return -EROFS;
+
+       err = leb_write_lock(ubi, vol_id, lnum);
+       if (err)
+               return err;
+
+       pnum = vol->eba_tbl[lnum];
+       if (pnum >= 0) {
+               dbg_eba("write %d bytes at offset %d of LEB %d:%d, PEB %d",
+                       len, offset, vol_id, lnum, pnum);
+
+               err = ubi_io_write_data(ubi, buf, pnum, offset, len);
+               if (err) {
+                       ubi_warn(ubi, "failed to write data to PEB %d", pnum);
+                       if (err == -EIO && ubi->bad_allowed)
+                               err = recover_peb(ubi, pnum, vol_id, lnum, buf,
+                                                 offset, len);
+                       if (err)
+                               ubi_ro_mode(ubi);
+               }
+               leb_write_unlock(ubi, vol_id, lnum);
+               return err;
+       }
+
+       /*
+        * The logical eraseblock is not mapped. We have to get a free physical
+        * eraseblock and write the volume identifier header there first.
+        */
+       vid_hdr = ubi_zalloc_vid_hdr(ubi, GFP_NOFS);
+       if (!vid_hdr) {
+               leb_write_unlock(ubi, vol_id, lnum);
+               return -ENOMEM;
+       }
+
+       vid_hdr->vol_type = UBI_VID_DYNAMIC;
+       vid_hdr->sqnum = cpu_to_be64(ubi_next_sqnum(ubi));
+       vid_hdr->vol_id = cpu_to_be32(vol_id);
+       vid_hdr->lnum = cpu_to_be32(lnum);
+       vid_hdr->compat = ubi_get_compat(ubi, vol_id);
+       vid_hdr->data_pad = cpu_to_be32(vol->data_pad);
+
+retry:
+       pnum = ubi_wl_get_peb(ubi);
+       if (pnum < 0) {
+               ubi_free_vid_hdr(ubi, vid_hdr);
+               leb_write_unlock(ubi, vol_id, lnum);
+               up_read(&ubi->fm_eba_sem);
+               return pnum;
+       }
+
+       dbg_eba("write VID hdr and %d bytes at offset %d of LEB %d:%d, PEB %d",
+               len, offset, vol_id, lnum, pnum);
+
+       err = ubi_io_write_vid_hdr(ubi, pnum, vid_hdr);
+       if (err) {
+               ubi_warn(ubi, "failed to write VID header to LEB %d:%d, PEB %d",
+                        vol_id, lnum, pnum);
+               up_read(&ubi->fm_eba_sem);
+               goto write_error;
+       }
+
+       if (len) {
+               err = ubi_io_write_data(ubi, buf, pnum, offset, len);
+               if (err) {
+                       ubi_warn(ubi, "failed to write %d bytes at offset %d of LEB %d:%d, PEB %d",
+                                len, offset, vol_id, lnum, pnum);
+                       up_read(&ubi->fm_eba_sem);
+                       goto write_error;
+               }
+       }
+
+       vol->eba_tbl[lnum] = pnum;
+       up_read(&ubi->fm_eba_sem);
+
+       leb_write_unlock(ubi, vol_id, lnum);
+       ubi_free_vid_hdr(ubi, vid_hdr);
+       return 0;
+
+write_error:
+       if (err != -EIO || !ubi->bad_allowed) {
+               ubi_ro_mode(ubi);
+               leb_write_unlock(ubi, vol_id, lnum);
+               ubi_free_vid_hdr(ubi, vid_hdr);
+               return err;
+       }
+
+       /*
+        * Fortunately, this is the first write operation to this physical
+        * eraseblock, so just put it and request a new one. We assume that if
+        * this physical eraseblock went bad, the erase code will handle that.
+        */
+       err = ubi_wl_put_peb(ubi, vol_id, lnum, pnum, 1);
+       if (err || ++tries > UBI_IO_RETRIES) {
+               ubi_ro_mode(ubi);
+               leb_write_unlock(ubi, vol_id, lnum);
+               ubi_free_vid_hdr(ubi, vid_hdr);
+               return err;
+       }
+
+       vid_hdr->sqnum = cpu_to_be64(ubi_next_sqnum(ubi));
+       ubi_msg(ubi, "try another PEB");
+       goto retry;
+}
+
+/**
+ * ubi_eba_write_leb_st - write data to static volume.
+ * @ubi: UBI device description object
+ * @vol: volume description object
+ * @lnum: logical eraseblock number
+ * @buf: data to write
+ * @len: how many bytes to write
+ * @used_ebs: how many logical eraseblocks will this volume contain
+ *
+ * This function writes data to logical eraseblock @lnum of static volume
+ * @vol. The @used_ebs argument should contain total number of logical
+ * eraseblock in this static volume.
+ *
+ * When writing to the last logical eraseblock, the @len argument doesn't have
+ * to be aligned to the minimal I/O unit size. Instead, it has to be equivalent
+ * to the real data size, although the @buf buffer has to contain the
+ * alignment. In all other cases, @len has to be aligned.
+ *
+ * It is prohibited to write more than once to logical eraseblocks of static
+ * volumes. This function returns zero in case of success and a negative error
+ * code in case of failure.
+ */
+int ubi_eba_write_leb_st(struct ubi_device *ubi, struct ubi_volume *vol,
+                        int lnum, const void *buf, int len, int used_ebs)
+{
+       int err, pnum, tries = 0, data_size = len, vol_id = vol->vol_id;
+       struct ubi_vid_hdr *vid_hdr;
+       uint32_t crc;
+
+       if (ubi->ro_mode)
+               return -EROFS;
+
+       if (lnum == used_ebs - 1)
+               /* If this is the last LEB @len may be unaligned */
+               len = ALIGN(data_size, ubi->min_io_size);
+       else
+               ubi_assert(!(len & (ubi->min_io_size - 1)));
+
+       vid_hdr = ubi_zalloc_vid_hdr(ubi, GFP_NOFS);
+       if (!vid_hdr)
+               return -ENOMEM;
+
+       err = leb_write_lock(ubi, vol_id, lnum);
+       if (err) {
+               ubi_free_vid_hdr(ubi, vid_hdr);
+               return err;
+       }
+
+       vid_hdr->sqnum = cpu_to_be64(ubi_next_sqnum(ubi));
+       vid_hdr->vol_id = cpu_to_be32(vol_id);
+       vid_hdr->lnum = cpu_to_be32(lnum);
+       vid_hdr->compat = ubi_get_compat(ubi, vol_id);
+       vid_hdr->data_pad = cpu_to_be32(vol->data_pad);
+
+       crc = crc32(UBI_CRC32_INIT, buf, data_size);
+       vid_hdr->vol_type = UBI_VID_STATIC;
+       vid_hdr->data_size = cpu_to_be32(data_size);
+       vid_hdr->used_ebs = cpu_to_be32(used_ebs);
+       vid_hdr->data_crc = cpu_to_be32(crc);
+
+retry:
+       pnum = ubi_wl_get_peb(ubi);
+       if (pnum < 0) {
+               ubi_free_vid_hdr(ubi, vid_hdr);
+               leb_write_unlock(ubi, vol_id, lnum);
+               up_read(&ubi->fm_eba_sem);
+               return pnum;
+       }
+
+       dbg_eba("write VID hdr and %d bytes at LEB %d:%d, PEB %d, used_ebs %d",
+               len, vol_id, lnum, pnum, used_ebs);
+
+       err = ubi_io_write_vid_hdr(ubi, pnum, vid_hdr);
+       if (err) {
+               ubi_warn(ubi, "failed to write VID header to LEB %d:%d, PEB %d",
+                        vol_id, lnum, pnum);
+               up_read(&ubi->fm_eba_sem);
+               goto write_error;
+       }
+
+       err = ubi_io_write_data(ubi, buf, pnum, 0, len);
+       if (err) {
+               ubi_warn(ubi, "failed to write %d bytes of data to PEB %d",
+                        len, pnum);
+               up_read(&ubi->fm_eba_sem);
+               goto write_error;
+       }
+
+       ubi_assert(vol->eba_tbl[lnum] < 0);
+       vol->eba_tbl[lnum] = pnum;
+       up_read(&ubi->fm_eba_sem);
+
+       leb_write_unlock(ubi, vol_id, lnum);
+       ubi_free_vid_hdr(ubi, vid_hdr);
+       return 0;
+
+write_error:
+       if (err != -EIO || !ubi->bad_allowed) {
+               /*
+                * This flash device does not admit of bad eraseblocks or
+                * something nasty and unexpected happened. Switch to read-only
+                * mode just in case.
+                */
+               ubi_ro_mode(ubi);
+               leb_write_unlock(ubi, vol_id, lnum);
+               ubi_free_vid_hdr(ubi, vid_hdr);
+               return err;
+       }
+
+       err = ubi_wl_put_peb(ubi, vol_id, lnum, pnum, 1);
+       if (err || ++tries > UBI_IO_RETRIES) {
+               ubi_ro_mode(ubi);
+               leb_write_unlock(ubi, vol_id, lnum);
+               ubi_free_vid_hdr(ubi, vid_hdr);
+               return err;
+       }
+
+       vid_hdr->sqnum = cpu_to_be64(ubi_next_sqnum(ubi));
+       ubi_msg(ubi, "try another PEB");
+       goto retry;
+}
+
+/*
+ * ubi_eba_atomic_leb_change - change logical eraseblock atomically.
+ * @ubi: UBI device description object
+ * @vol: volume description object
+ * @lnum: logical eraseblock number
+ * @buf: data to write
+ * @len: how many bytes to write
+ *
+ * This function changes the contents of a logical eraseblock atomically. @buf
+ * has to contain new logical eraseblock data, and @len - the length of the
+ * data, which has to be aligned. This function guarantees that in case of an
+ * unclean reboot the old contents is preserved. Returns zero in case of
+ * success and a negative error code in case of failure.
+ *
+ * UBI reserves one LEB for the "atomic LEB change" operation, so only one
+ * LEB change may be done at a time. This is ensured by @ubi->alc_mutex.
+ */
+int ubi_eba_atomic_leb_change(struct ubi_device *ubi, struct ubi_volume *vol,
+                             int lnum, const void *buf, int len)
+{
+       int err, pnum, old_pnum, tries = 0, vol_id = vol->vol_id;
+       struct ubi_vid_hdr *vid_hdr;
+       uint32_t crc;
+
+       if (ubi->ro_mode)
+               return -EROFS;
+
+       if (len == 0) {
+               /*
+                * Special case when data length is zero. In this case the LEB
+                * has to be unmapped and mapped somewhere else.
+                */
+               err = ubi_eba_unmap_leb(ubi, vol, lnum);
+               if (err)
+                       return err;
+               return ubi_eba_write_leb(ubi, vol, lnum, NULL, 0, 0);
+       }
+
+       vid_hdr = ubi_zalloc_vid_hdr(ubi, GFP_NOFS);
+       if (!vid_hdr)
+               return -ENOMEM;
+
+       mutex_lock(&ubi->alc_mutex);
+       err = leb_write_lock(ubi, vol_id, lnum);
+       if (err)
+               goto out_mutex;
+
+       vid_hdr->sqnum = cpu_to_be64(ubi_next_sqnum(ubi));
+       vid_hdr->vol_id = cpu_to_be32(vol_id);
+       vid_hdr->lnum = cpu_to_be32(lnum);
+       vid_hdr->compat = ubi_get_compat(ubi, vol_id);
+       vid_hdr->data_pad = cpu_to_be32(vol->data_pad);
+
+       crc = crc32(UBI_CRC32_INIT, buf, len);
+       vid_hdr->vol_type = UBI_VID_DYNAMIC;
+       vid_hdr->data_size = cpu_to_be32(len);
+       vid_hdr->copy_flag = 1;
+       vid_hdr->data_crc = cpu_to_be32(crc);
+
+retry:
+       pnum = ubi_wl_get_peb(ubi);
+       if (pnum < 0) {
+               err = pnum;
+               up_read(&ubi->fm_eba_sem);
+               goto out_leb_unlock;
+       }
+
+       dbg_eba("change LEB %d:%d, PEB %d, write VID hdr to PEB %d",
+               vol_id, lnum, vol->eba_tbl[lnum], pnum);
+
+       err = ubi_io_write_vid_hdr(ubi, pnum, vid_hdr);
+       if (err) {
+               ubi_warn(ubi, "failed to write VID header to LEB %d:%d, PEB %d",
+                        vol_id, lnum, pnum);
+               up_read(&ubi->fm_eba_sem);
+               goto write_error;
+       }
+
+       err = ubi_io_write_data(ubi, buf, pnum, 0, len);
+       if (err) {
+               ubi_warn(ubi, "failed to write %d bytes of data to PEB %d",
+                        len, pnum);
+               up_read(&ubi->fm_eba_sem);
+               goto write_error;
+       }
+
+       old_pnum = vol->eba_tbl[lnum];
+       vol->eba_tbl[lnum] = pnum;
+       up_read(&ubi->fm_eba_sem);
+
+       if (old_pnum >= 0) {
+               err = ubi_wl_put_peb(ubi, vol_id, lnum, old_pnum, 0);
+               if (err)
+                       goto out_leb_unlock;
+       }
+
+out_leb_unlock:
+       leb_write_unlock(ubi, vol_id, lnum);
+out_mutex:
+       mutex_unlock(&ubi->alc_mutex);
+       ubi_free_vid_hdr(ubi, vid_hdr);
+       return err;
+
+write_error:
+       if (err != -EIO || !ubi->bad_allowed) {
+               /*
+                * This flash device does not admit of bad eraseblocks or
+                * something nasty and unexpected happened. Switch to read-only
+                * mode just in case.
+                */
+               ubi_ro_mode(ubi);
+               goto out_leb_unlock;
+       }
+
+       err = ubi_wl_put_peb(ubi, vol_id, lnum, pnum, 1);
+       if (err || ++tries > UBI_IO_RETRIES) {
+               ubi_ro_mode(ubi);
+               goto out_leb_unlock;
+       }
+
+       vid_hdr->sqnum = cpu_to_be64(ubi_next_sqnum(ubi));
+       ubi_msg(ubi, "try another PEB");
+       goto retry;
+}
+
+/**
+ * is_error_sane - check whether a read error is sane.
+ * @err: code of the error happened during reading
+ *
+ * This is a helper function for 'ubi_eba_copy_leb()' which is called when we
+ * cannot read data from the target PEB (an error @err happened). If the error
+ * code is sane, then we treat this error as non-fatal. Otherwise the error is
+ * fatal and UBI will be switched to R/O mode later.
+ *
+ * The idea is that we try not to switch to R/O mode if the read error is
+ * something which suggests there was a real read problem. E.g., %-EIO. Or a
+ * memory allocation failed (-%ENOMEM). Otherwise, it is safer to switch to R/O
+ * mode, simply because we do not know what happened at the MTD level, and we
+ * cannot handle this. E.g., the underlying driver may have become crazy, and
+ * it is safer to switch to R/O mode to preserve the data.
+ *
+ * And bear in mind, this is about reading from the target PEB, i.e. the PEB
+ * which we have just written.
+ */
+static int is_error_sane(int err)
+{
+       if (err == -EIO || err == -ENOMEM || err == UBI_IO_BAD_HDR ||
+           err == UBI_IO_BAD_HDR_EBADMSG || err == -ETIMEDOUT)
+               return 0;
+       return 1;
+}
+
+/**
+ * ubi_eba_copy_leb - copy logical eraseblock.
+ * @ubi: UBI device description object
+ * @from: physical eraseblock number from where to copy
+ * @to: physical eraseblock number where to copy
+ * @vid_hdr: VID header of the @from physical eraseblock
+ *
+ * This function copies logical eraseblock from physical eraseblock @from to
+ * physical eraseblock @to. The @vid_hdr buffer may be changed by this
+ * function. Returns:
+ *   o %0 in case of success;
+ *   o %MOVE_CANCEL_RACE, %MOVE_TARGET_WR_ERR, %MOVE_TARGET_BITFLIPS, etc;
+ *   o a negative error code in case of failure.
+ */
+int ubi_eba_copy_leb(struct ubi_device *ubi, int from, int to,
+                    struct ubi_vid_hdr *vid_hdr)
+{
+       int err, vol_id, lnum, data_size, aldata_size, idx;
+       struct ubi_volume *vol;
+       uint32_t crc;
+
+       vol_id = be32_to_cpu(vid_hdr->vol_id);
+       lnum = be32_to_cpu(vid_hdr->lnum);
+
+       dbg_wl("copy LEB %d:%d, PEB %d to PEB %d", vol_id, lnum, from, to);
+
+       if (vid_hdr->vol_type == UBI_VID_STATIC) {
+               data_size = be32_to_cpu(vid_hdr->data_size);
+               aldata_size = ALIGN(data_size, ubi->min_io_size);
+       } else
+               data_size = aldata_size =
+                           ubi->leb_size - be32_to_cpu(vid_hdr->data_pad);
+
+       idx = vol_id2idx(ubi, vol_id);
+       spin_lock(&ubi->volumes_lock);
+       /*
+        * Note, we may race with volume deletion, which means that the volume
+        * this logical eraseblock belongs to might be being deleted. Since the
+        * volume deletion un-maps all the volume's logical eraseblocks, it will
+        * be locked in 'ubi_wl_put_peb()' and wait for the WL worker to finish.
+        */
+       vol = ubi->volumes[idx];
+       spin_unlock(&ubi->volumes_lock);
+       if (!vol) {
+               /* No need to do further work, cancel */
+               dbg_wl("volume %d is being removed, cancel", vol_id);
+               return MOVE_CANCEL_RACE;
+       }
+
+       /*
+        * We do not want anybody to write to this logical eraseblock while we
+        * are moving it, so lock it.
+        *
+        * Note, we are using non-waiting locking here, because we cannot sleep
+        * on the LEB, since it may cause deadlocks. Indeed, imagine a task is
+        * unmapping the LEB which is mapped to the PEB we are going to move
+        * (@from). This task locks the LEB and goes sleep in the
+        * 'ubi_wl_put_peb()' function on the @ubi->move_mutex. In turn, we are
+        * holding @ubi->move_mutex and go sleep on the LEB lock. So, if the
+        * LEB is already locked, we just do not move it and return
+        * %MOVE_RETRY. Note, we do not return %MOVE_CANCEL_RACE here because
+        * we do not know the reasons of the contention - it may be just a
+        * normal I/O on this LEB, so we want to re-try.
+        */
+       err = leb_write_trylock(ubi, vol_id, lnum);
+       if (err) {
+               dbg_wl("contention on LEB %d:%d, cancel", vol_id, lnum);
+               return MOVE_RETRY;
+       }
+
+       /*
+        * The LEB might have been put meanwhile, and the task which put it is
+        * probably waiting on @ubi->move_mutex. No need to continue the work,
+        * cancel it.
+        */
+       if (vol->eba_tbl[lnum] != from) {
+               dbg_wl("LEB %d:%d is no longer mapped to PEB %d, mapped to PEB %d, cancel",
+                      vol_id, lnum, from, vol->eba_tbl[lnum]);
+               err = MOVE_CANCEL_RACE;
+               goto out_unlock_leb;
+       }
+
+       /*
+        * OK, now the LEB is locked and we can safely start moving it. Since
+        * this function utilizes the @ubi->peb_buf buffer which is shared
+        * with some other functions - we lock the buffer by taking the
+        * @ubi->buf_mutex.
+        */
+       mutex_lock(&ubi->buf_mutex);
+       dbg_wl("read %d bytes of data", aldata_size);
+       err = ubi_io_read_data(ubi, ubi->peb_buf, from, 0, aldata_size);
+       if (err && err != UBI_IO_BITFLIPS) {
+               ubi_warn(ubi, "error %d while reading data from PEB %d",
+                        err, from);
+               err = MOVE_SOURCE_RD_ERR;
+               goto out_unlock_buf;
+       }
+
+       /*
+        * Now we have got to calculate how much data we have to copy. In
+        * case of a static volume it is fairly easy - the VID header contains
+        * the data size. In case of a dynamic volume it is more difficult - we
+        * have to read the contents, cut 0xFF bytes from the end and copy only
+        * the first part. We must do this to avoid writing 0xFF bytes as it
+        * may have some side-effects. And not only this. It is important not
+        * to include those 0xFFs to CRC because later the they may be filled
+        * by data.
+        */
+       if (vid_hdr->vol_type == UBI_VID_DYNAMIC)
+               aldata_size = data_size =
+                       ubi_calc_data_len(ubi, ubi->peb_buf, data_size);
+
+       cond_resched();
+       crc = crc32(UBI_CRC32_INIT, ubi->peb_buf, data_size);
+       cond_resched();
+
+       /*
+        * It may turn out to be that the whole @from physical eraseblock
+        * contains only 0xFF bytes. Then we have to only write the VID header
+        * and do not write any data. This also means we should not set
+        * @vid_hdr->copy_flag, @vid_hdr->data_size, and @vid_hdr->data_crc.
+        */
+       if (data_size > 0) {
+               vid_hdr->copy_flag = 1;
+               vid_hdr->data_size = cpu_to_be32(data_size);
+               vid_hdr->data_crc = cpu_to_be32(crc);
+       }
+       vid_hdr->sqnum = cpu_to_be64(ubi_next_sqnum(ubi));
+
+       err = ubi_io_write_vid_hdr(ubi, to, vid_hdr);
+       if (err) {
+               if (err == -EIO)
+                       err = MOVE_TARGET_WR_ERR;
+               goto out_unlock_buf;
+       }
+
+       cond_resched();
+
+       /* Read the VID header back and check if it was written correctly */
+       err = ubi_io_read_vid_hdr(ubi, to, vid_hdr, 1);
+       if (err) {
+               if (err != UBI_IO_BITFLIPS) {
+                       ubi_warn(ubi, "error %d while reading VID header back from PEB %d",
+                                err, to);
+                       if (is_error_sane(err))
+                               err = MOVE_TARGET_RD_ERR;
+               } else
+                       err = MOVE_TARGET_BITFLIPS;
+               goto out_unlock_buf;
+       }
+
+       if (data_size > 0) {
+               err = ubi_io_write_data(ubi, ubi->peb_buf, to, 0, aldata_size);
+               if (err) {
+                       if (err == -EIO)
+                               err = MOVE_TARGET_WR_ERR;
+                       goto out_unlock_buf;
+               }
+
+               cond_resched();
+
+               /*
+                * We've written the data and are going to read it back to make
+                * sure it was written correctly.
+                */
+               memset(ubi->peb_buf, 0xFF, aldata_size);
+               err = ubi_io_read_data(ubi, ubi->peb_buf, to, 0, aldata_size);
+               if (err) {
+                       if (err != UBI_IO_BITFLIPS) {
+                               ubi_warn(ubi, "error %d while reading data back from PEB %d",
+                                        err, to);
+                               if (is_error_sane(err))
+                                       err = MOVE_TARGET_RD_ERR;
+                       } else
+                               err = MOVE_TARGET_BITFLIPS;
+                       goto out_unlock_buf;
+               }
+
+               cond_resched();
+
+               if (crc != crc32(UBI_CRC32_INIT, ubi->peb_buf, data_size)) {
+                       ubi_warn(ubi, "read data back from PEB %d and it is different",
+                                to);
+                       err = -EINVAL;
+                       goto out_unlock_buf;
+               }
+       }
+
+       ubi_assert(vol->eba_tbl[lnum] == from);
+       down_read(&ubi->fm_eba_sem);
+       vol->eba_tbl[lnum] = to;
+       up_read(&ubi->fm_eba_sem);
+
+out_unlock_buf:
+       mutex_unlock(&ubi->buf_mutex);
+out_unlock_leb:
+       leb_write_unlock(ubi, vol_id, lnum);
+       return err;
+}
+
+/**
+ * print_rsvd_warning - warn about not having enough reserved PEBs.
+ * @ubi: UBI device description object
+ *
+ * This is a helper function for 'ubi_eba_init()' which is called when UBI
+ * cannot reserve enough PEBs for bad block handling. This function makes a
+ * decision whether we have to print a warning or not. The algorithm is as
+ * follows:
+ *   o if this is a new UBI image, then just print the warning
+ *   o if this is an UBI image which has already been used for some time, print
+ *     a warning only if we can reserve less than 10% of the expected amount of
+ *     the reserved PEB.
+ *
+ * The idea is that when UBI is used, PEBs become bad, and the reserved pool
+ * of PEBs becomes smaller, which is normal and we do not want to scare users
+ * with a warning every time they attach the MTD device. This was an issue
+ * reported by real users.
+ */
+static void print_rsvd_warning(struct ubi_device *ubi,
+                              struct ubi_attach_info *ai)
+{
+       /*
+        * The 1 << 18 (256KiB) number is picked randomly, just a reasonably
+        * large number to distinguish between newly flashed and used images.
+        */
+       if (ai->max_sqnum > (1 << 18)) {
+               int min = ubi->beb_rsvd_level / 10;
+
+               if (!min)
+                       min = 1;
+               if (ubi->beb_rsvd_pebs > min)
+                       return;
+       }
+
+       ubi_warn(ubi, "cannot reserve enough PEBs for bad PEB handling, reserved %d, need %d",
+                ubi->beb_rsvd_pebs, ubi->beb_rsvd_level);
+       if (ubi->corr_peb_count)
+               ubi_warn(ubi, "%d PEBs are corrupted and not used",
+                        ubi->corr_peb_count);
+}
+
+/**
+ * self_check_eba - run a self check on the EBA table constructed by fastmap.
+ * @ubi: UBI device description object
+ * @ai_fastmap: UBI attach info object created by fastmap
+ * @ai_scan: UBI attach info object created by scanning
+ *
+ * Returns < 0 in case of an internal error, 0 otherwise.
+ * If a bad EBA table entry was found it will be printed out and
+ * ubi_assert() triggers.
+ */
+int self_check_eba(struct ubi_device *ubi, struct ubi_attach_info *ai_fastmap,
+                  struct ubi_attach_info *ai_scan)
+{
+       int i, j, num_volumes, ret = 0;
+       int **scan_eba, **fm_eba;
+       struct ubi_ainf_volume *av;
+       struct ubi_volume *vol;
+       struct ubi_ainf_peb *aeb;
+       struct rb_node *rb;
+
+       num_volumes = ubi->vtbl_slots + UBI_INT_VOL_COUNT;
+
+       scan_eba = kmalloc(sizeof(*scan_eba) * num_volumes, GFP_KERNEL);
+       if (!scan_eba)
+               return -ENOMEM;
+
+       fm_eba = kmalloc(sizeof(*fm_eba) * num_volumes, GFP_KERNEL);
+       if (!fm_eba) {
+               kfree(scan_eba);
+               return -ENOMEM;
+       }
+
+       for (i = 0; i < num_volumes; i++) {
+               vol = ubi->volumes[i];
+               if (!vol)
+                       continue;
+
+               scan_eba[i] = kmalloc(vol->reserved_pebs * sizeof(**scan_eba),
+                                     GFP_KERNEL);
+               if (!scan_eba[i]) {
+                       ret = -ENOMEM;
+                       goto out_free;
+               }
+
+               fm_eba[i] = kmalloc(vol->reserved_pebs * sizeof(**fm_eba),
+                                   GFP_KERNEL);
+               if (!fm_eba[i]) {
+                       ret = -ENOMEM;
+                       goto out_free;
+               }
+
+               for (j = 0; j < vol->reserved_pebs; j++)
+                       scan_eba[i][j] = fm_eba[i][j] = UBI_LEB_UNMAPPED;
+
+               av = ubi_find_av(ai_scan, idx2vol_id(ubi, i));
+               if (!av)
+                       continue;
+
+               ubi_rb_for_each_entry(rb, aeb, &av->root, u.rb)
+                       scan_eba[i][aeb->lnum] = aeb->pnum;
+
+               av = ubi_find_av(ai_fastmap, idx2vol_id(ubi, i));
+               if (!av)
+                       continue;
+
+               ubi_rb_for_each_entry(rb, aeb, &av->root, u.rb)
+                       fm_eba[i][aeb->lnum] = aeb->pnum;
+
+               for (j = 0; j < vol->reserved_pebs; j++) {
+                       if (scan_eba[i][j] != fm_eba[i][j]) {
+                               if (scan_eba[i][j] == UBI_LEB_UNMAPPED ||
+                                       fm_eba[i][j] == UBI_LEB_UNMAPPED)
+                                       continue;
+
+                               ubi_err(ubi, "LEB:%i:%i is PEB:%i instead of %i!",
+                                       vol->vol_id, i, fm_eba[i][j],
+                                       scan_eba[i][j]);
+                               ubi_assert(0);
+                       }
+               }
+       }
+
+out_free:
+       for (i = 0; i < num_volumes; i++) {
+               if (!ubi->volumes[i])
+                       continue;
+
+               kfree(scan_eba[i]);
+               kfree(fm_eba[i]);
+       }
+
+       kfree(scan_eba);
+       kfree(fm_eba);
+       return ret;
+}
+
+/**
+ * ubi_eba_init - initialize the EBA sub-system using attaching information.
+ * @ubi: UBI device description object
+ * @ai: attaching information
+ *
+ * This function returns zero in case of success and a negative error code in
+ * case of failure.
+ */
+int ubi_eba_init(struct ubi_device *ubi, struct ubi_attach_info *ai)
+{
+       int i, j, err, num_volumes;
+       struct ubi_ainf_volume *av;
+       struct ubi_volume *vol;
+       struct ubi_ainf_peb *aeb;
+       struct rb_node *rb;
+
+       dbg_eba("initialize EBA sub-system");
+
+       spin_lock_init(&ubi->ltree_lock);
+       mutex_init(&ubi->alc_mutex);
+       ubi->ltree = RB_ROOT;
+
+       ubi->global_sqnum = ai->max_sqnum + 1;
+       num_volumes = ubi->vtbl_slots + UBI_INT_VOL_COUNT;
+
+       for (i = 0; i < num_volumes; i++) {
+               vol = ubi->volumes[i];
+               if (!vol)
+                       continue;
+
+               cond_resched();
+
+               vol->eba_tbl = kmalloc(vol->reserved_pebs * sizeof(int),
+                                      GFP_KERNEL);
+               if (!vol->eba_tbl) {
+                       err = -ENOMEM;
+                       goto out_free;
+               }
+
+               for (j = 0; j < vol->reserved_pebs; j++)
+                       vol->eba_tbl[j] = UBI_LEB_UNMAPPED;
+
+               av = ubi_find_av(ai, idx2vol_id(ubi, i));
+               if (!av)
+                       continue;
+
+               ubi_rb_for_each_entry(rb, aeb, &av->root, u.rb) {
+                       if (aeb->lnum >= vol->reserved_pebs)
+                               /*
+                                * This may happen in case of an unclean reboot
+                                * during re-size.
+                                */
+                               ubi_move_aeb_to_list(av, aeb, &ai->erase);
+                       else
+                               vol->eba_tbl[aeb->lnum] = aeb->pnum;
+               }
+       }
+
+       if (ubi->avail_pebs < EBA_RESERVED_PEBS) {
+               ubi_err(ubi, "no enough physical eraseblocks (%d, need %d)",
+                       ubi->avail_pebs, EBA_RESERVED_PEBS);
+               if (ubi->corr_peb_count)
+                       ubi_err(ubi, "%d PEBs are corrupted and not used",
+                               ubi->corr_peb_count);
+               err = -ENOSPC;
+               goto out_free;
+       }
+       ubi->avail_pebs -= EBA_RESERVED_PEBS;
+       ubi->rsvd_pebs += EBA_RESERVED_PEBS;
+
+       if (ubi->bad_allowed) {
+               ubi_calculate_reserved(ubi);
+
+               if (ubi->avail_pebs < ubi->beb_rsvd_level) {
+                       /* No enough free physical eraseblocks */
+                       ubi->beb_rsvd_pebs = ubi->avail_pebs;
+                       print_rsvd_warning(ubi, ai);
+               } else
+                       ubi->beb_rsvd_pebs = ubi->beb_rsvd_level;
+
+               ubi->avail_pebs -= ubi->beb_rsvd_pebs;
+               ubi->rsvd_pebs  += ubi->beb_rsvd_pebs;
+       }
+
+       dbg_eba("EBA sub-system is initialized");
+       return 0;
+
+out_free:
+       for (i = 0; i < num_volumes; i++) {
+               if (!ubi->volumes[i])
+                       continue;
+               kfree(ubi->volumes[i]->eba_tbl);
+               ubi->volumes[i]->eba_tbl = NULL;
+       }
+       return err;
+}