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    Subject[PATCH 10/22 take 3] UBI: EBA unit
    diff -auNrp tmp-from/drivers/mtd/ubi/eba.c tmp-to/drivers/mtd/ubi/eba.c
    --- tmp-from/drivers/mtd/ubi/eba.c 1970-01-01 02:00:00.000000000 +0200
    +++ tmp-to/drivers/mtd/ubi/eba.c 2007-03-14 17:15:50.000000000 +0200
    @@ -0,0 +1,1735 @@
    +/*
    + * 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 B. Bityutskiy
    + */
    +
    +/*
    + * The UBI Eraseblock Association (EBA) unit.
    + *
    + * This unit maintains the Eraseblock Association Table (EBA table). The EBA
    + * table is a data structure which maps (volume ID, logical eraseblock number)
    + * pairs to physical eraseblock numbers.
    + *
    + * All the UBI input/output goes via the EBA unit. The only reservation is made
    + * for the initialization time when different units may directly do
    + * input/output from physical eraseblocks.
    + *
    + * Although in this implementation the EBA table is fully kept and managed in
    + * RAM, which assumes poor UBI scalability, it might be (partially) maintained
    + * on flash in future implementations.
    + *
    + * The EBA unit 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 a lock tree. The lock tree is
    + * an RB-tree which refers all the currently locked logical eraseblocks. The
    + * lock tree elements are &struct ubi_eba_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"
    +
    +/**
    + * struct ubi_eba_tbl_rec - a record in the eraseblock association table.
    + *
    + * @pnum: physical eraseblock number
    + * @leb_ver: LEB version (obsolete)
    + *
    + * This structure represents a record in the eraseblock association table.
    + */
    +struct ubi_eba_tbl_rec {
    + int pnum;
    + uint32_t leb_ver; /* FIXME: obsolete, to be removed */
    +};
    +
    +/**
    + * struct ubi_eba_tbl_volume - a volume in the the eraseblock association
    + * table.
    + *
    + * @recs: an array of per-logical eraseblock records (for each logical
    + * eraseblock of this volume)
    + * @leb_count: how many logical eraseblock this volume has
    + */
    +struct ubi_eba_tbl_volume {
    + struct ubi_eba_tbl_rec *recs;
    + int leb_count;
    +};
    +
    +/**
    + * struct ubi_eba_ltree_entry - an entry in the lock tree.
    + *
    + * @rb: links RB-tree nodes
    + * @vol_id: volume ID of the locked logical eraseblock
    + * @lnum: locked logical eraseblock number
    + * @users: how many tasks are using this logical eraseblock or wait for it
    + * @mutex: a read/write mutex to implement read/write access serialization to
    + * the (@vol_id, @lnum) logical eraseblock
    + *
    + * When a logical eraseblock is being locked - corresponding &struct
    + * ubi_eba_ltree_entry object is inserted to the lock tree (@eba->ltree).
    + */
    +struct ubi_eba_ltree_entry {
    + struct rb_node rb;
    + int vol_id;
    + int lnum;
    + int users;
    + struct rw_semaphore mutex;
    +};
    +
    +/*
    + * The top-most bit in logical-to-physical eraseblock mappings is used to
    + * indicate that the logical eraseblock is not mapped.
    + */
    +#define NOT_MAPPED 0x80000000
    +
    +#ifdef CONFIG_MTD_UBI_DEBUG_PARANOID_EBA
    +static int paranoid_check_leb(const struct ubi_info *ubi, int pnum, int vol_id,
    + int lnum, const struct ubi_vid_hdr *vid_hdr);
    +static int paranoid_check_leb_locked(struct ubi_info *ubi, int vol_id,
    + int lnum);
    +#else
    +#define paranoid_check_leb(ubi, vol_id, pnum, lnum, vid_hdr) 0
    +#define paranoid_check_leb_locked(ubi, vol_id, lnum)
    +#endif
    +
    +/* Slab cache for lock-tree entries */
    +static struct kmem_cache *eba_ltree_entry_slab;
    +
    +/**
    + * vol_id2idx - turn volume ID to the EBA table index.
    + *
    + * @ubi: the UBI device description object
    + * @vol_id: the volume ID
    + */
    +static inline int vol_id2idx(const struct ubi_info *ubi, int vol_id)
    +{
    + if (vol_id >= UBI_INTERNAL_VOL_START)
    + return vol_id - UBI_INTERNAL_VOL_START + ubi->vtbl.vt_slots;
    + else
    + return vol_id;
    +}
    +
    +/**
    + * idx2vol_id - turn an EBA table index to the volume ID.
    + *
    + * @ubi: the UBI device description object
    + * @idx: the EBA table index
    + */
    +static inline int idx2vol_id(const struct ubi_info *ubi, int idx)
    +{
    + if (idx >= ubi->vtbl.vt_slots)
    + return idx - ubi->vtbl.vt_slots + UBI_INTERNAL_VOL_START;
    + else
    + return idx;
    +}
    +
    +/**
    + * leb_get_ver - get logical eraseblock version.
    + *
    + * @ubi: the UBI device description object
    + * @vol_id: the volume ID
    + * @lnum: the logical eraseblock number
    + *
    + * The logical eraseblock has to be locked. Note, all this leb_ver stuff is
    + * obsolete and will be removed eventually. FIXME: to be removed together with
    + * leb_ver support.
    + */
    +static inline int leb_get_ver(struct ubi_info *ubi, int vol_id, int lnum)
    +{
    + int idx, leb_ver;
    +
    + idx = vol_id2idx(ubi, vol_id);
    +
    + spin_lock(&ubi->eba.eba_tbl_lock);
    + ubi_assert(ubi->eba.eba_tbl[idx].recs);
    + leb_ver = ubi->eba.eba_tbl[idx].recs[lnum].leb_ver;
    + spin_unlock(&ubi->eba.eba_tbl_lock);
    +
    + return leb_ver;
    +}
    +
    +/**
    + * next_sqnum - get next sequence number.
    + *
    + * @ubi: the 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.
    + */
    +static unsigned long long next_sqnum(struct ubi_info *ubi)
    +{
    + unsigned long long sqnum;
    +
    + spin_lock(&ubi->eba.eba_tbl_lock);
    + sqnum = ubi->eba.global_sq_cnt++;
    + spin_unlock(&ubi->eba.eba_tbl_lock);
    +
    + return sqnum;
    +}
    +
    +/**
    + * leb_map - map a logical eraseblock to a physical eraseblock.
    + *
    + * @ubi: the UBI device description object
    + * @vol_id: the volume ID
    + * @lnum: the logical eraseblock number
    + * @pnum: the physical eraseblock
    + *
    + * The logical eraseblock has to be locked.
    + */
    +static inline void leb_map(struct ubi_info *ubi, int vol_id, int lnum, int pnum)
    +{
    + int idx;
    +
    + idx = vol_id2idx(ubi, vol_id);
    + spin_lock(&ubi->eba.eba_tbl_lock);
    + ubi_assert(ubi->eba.eba_tbl[idx].recs);
    + ubi_assert(ubi->eba.eba_tbl[idx].recs[lnum].pnum < 0);
    + ubi->eba.eba_tbl[idx].recs[lnum].pnum = pnum;
    + spin_unlock(&ubi->eba.eba_tbl_lock);
    +}
    +
    +/**
    + * leb_unmap - un-map a logical eraseblock.
    + *
    + * @ubi: the UBI device description object
    + * @vol_id: the volume ID
    + * @lnum: the logical eraseblock number to unmap
    + *
    + * This function un-maps a logical eraseblock and increases its version. The
    + * logical eraseblock has to be locked.
    + */
    +static inline void leb_unmap(struct ubi_info *ubi, int vol_id, int lnum)
    +{
    + int idx;
    +
    + idx = vol_id2idx(ubi, vol_id);
    +
    + spin_lock(&ubi->eba.eba_tbl_lock);
    + ubi_assert(ubi->eba.eba_tbl[idx].recs);
    + ubi_assert(ubi->eba.eba_tbl[idx].recs[lnum].pnum >= 0);
    + ubi->eba.eba_tbl[idx].recs[lnum].pnum |= NOT_MAPPED;
    + ubi->eba.eba_tbl[idx].recs[lnum].leb_ver += 1;
    + spin_unlock(&ubi->eba.eba_tbl_lock);
    +}
    +
    +/**
    + * leb2peb - get physical eraseblock number by logical eraseblock number.
    + *
    + * @ubi: the UBI device description object
    + * @vol_id: the volume ID
    + * @lnum: the logical eraseblock number
    + *
    + * If the logical eraseblock is mapped, this function returns a positive
    + * physical eraseblock number. If it is not mapped, this function returns
    + * a negative number.
    + */
    +static inline int leb2peb(struct ubi_info *ubi, int vol_id, int lnum)
    +{
    + int idx, pnum;
    +
    + idx = vol_id2idx(ubi, vol_id);
    +
    + spin_lock(&ubi->eba.eba_tbl_lock);
    + ubi_assert(ubi->eba.eba_tbl[idx].recs);
    + pnum = ubi->eba.eba_tbl[idx].recs[lnum].pnum;
    + spin_unlock(&ubi->eba.eba_tbl_lock);
    +
    + return pnum;
    +}
    +
    +/**
    + * ubi_eba_mkvol - create EBA mapping for a new volume.
    + *
    + * @ubi: the UBI device description object
    + * @vol_id: ID of the new volume
    + * @leb_count: how many eraseblocks are reserved for this volume
    + *
    + * This function returns zero in case of success and a negative error code in
    + * case of failure.
    + */
    +int ubi_eba_mkvol(struct ubi_info *ubi, int vol_id, int reserved_pebs)
    +{
    + int i, idx, sz;
    + struct ubi_eba_tbl_rec *new_ebs;
    + struct ubi_eba_tbl_volume *eba_tbl = ubi->eba.eba_tbl;
    +
    + dbg_eba("create volume %d, size %d", vol_id, reserved_pebs);
    +
    + ubi_assert(vol_id >= 0);
    + ubi_assert(reserved_pebs > 0);
    + ubi_assert(!ubi_is_ivol(vol_id));
    + ubi_assert(vol_id < ubi->vtbl.vt_slots);
    +
    + if (ubi->io.ro_mode) {
    + dbg_err("read-only mode");
    + return -EROFS;
    + }
    +
    + sz = reserved_pebs * sizeof(struct ubi_eba_tbl_rec);
    + new_ebs = kmalloc(sz, GFP_KERNEL);
    + if (!new_ebs)
    + return -ENOMEM;
    +
    + for (i = 0; i < reserved_pebs; i++) {
    + new_ebs[i].pnum = NOT_MAPPED;
    + new_ebs[i].leb_ver = 0xFFFFFFF0;
    + }
    +
    + idx = vol_id2idx(ubi, vol_id);
    +
    + spin_lock(&ubi->eba.eba_tbl_lock);
    + ubi_assert(!eba_tbl[idx].recs);
    + eba_tbl[idx].recs = new_ebs;
    + eba_tbl[idx].leb_count = reserved_pebs;
    + spin_unlock(&ubi->eba.eba_tbl_lock);
    +
    + return 0;
    +}
    +
    +/**
    + * ubi_eba_rmvol - remove EBA mapping of a volume.
    + *
    + * @ubi: the UBI device description object
    + * @vol_id: ID of the volume to be removed
    + *
    + * This function removes a volume from the EBA table. It un-maps all the
    + * logical eraseblocks and the corresponding physical eraseblocks are scheduled
    + * for erasure. Returns zero in case of success and a negative error code in
    + * case of failure.
    + */
    +int ubi_eba_rmvol(struct ubi_info *ubi, int vol_id)
    +{
    + int err = 0, i, idx, to_put;
    + struct ubi_eba_tbl_rec *rm_ebs;
    + struct ubi_eba_tbl_volume *eba_tbl = ubi->eba.eba_tbl;
    +
    + dbg_eba("remove volume %d", vol_id);
    +
    + ubi_assert(vol_id >= 0);
    + ubi_assert(!ubi_is_ivol(vol_id));
    + ubi_assert(vol_id < ubi->vtbl.vt_slots);
    +
    + if (ubi->io.ro_mode) {
    + dbg_err("read-only mode");
    + return -EROFS;
    + }
    +
    + idx = vol_id2idx(ubi, vol_id);
    +
    + spin_lock(&ubi->eba.eba_tbl_lock);
    + ubi_assert(eba_tbl[idx].recs);
    + to_put = eba_tbl[idx].leb_count;
    + spin_unlock(&ubi->eba.eba_tbl_lock);
    +
    + for (i = 0; i < to_put; i++) {
    + err = ubi_eba_unmap_leb(ubi, vol_id, i);
    + if (err)
    + break;
    + }
    +
    + spin_lock(&ubi->eba.eba_tbl_lock);
    + rm_ebs = eba_tbl[idx].recs;
    + eba_tbl[idx].recs = NULL;
    + eba_tbl[idx].leb_count = 0;
    + spin_unlock(&ubi->eba.eba_tbl_lock);
    +
    + kfree(rm_ebs);
    + return err;
    +}
    +
    +/**
    + * ubi_eba_rsvol - re-size EBA mapping for a volume.
    + *
    + * @ubi: the UBI device description object
    + * @vol_id: ID of the volume to be re-sized
    + * @reserved_pebs: new count of physical eraseblocks in this volume
    + *
    + * This function changes the EBA table accordingly to the volume re-size
    + * operation. If the volume is actually shrunken, the dropped logical
    + * eraseblocks are got unmapped an thus, the corresponding physical eraseblocks
    + * are scheduled for erasure. This function returns zero in case of success and
    + * a negative error code in case of failure.
    + */
    +int ubi_eba_rsvol(struct ubi_info *ubi, int vol_id, int reserved_pebs)
    +{
    + int err = 0, i, idx, min, to_put, sz;
    + struct ubi_eba_tbl_rec *new_ebs, *old_ebs;
    + struct ubi_eba_tbl_volume *eba_tbl = ubi->eba.eba_tbl;
    +
    + dbg_eba("re-size volume %d to %d PEBs", vol_id, reserved_pebs);
    +
    + ubi_assert(vol_id >= 0);
    + ubi_assert(!ubi_is_ivol(vol_id));
    + ubi_assert(vol_id < ubi->vtbl.vt_slots);
    + ubi_assert(reserved_pebs > 0);
    +
    + if (ubi->io.ro_mode) {
    + dbg_err("read-only mode");
    + return -EROFS;
    + }
    +
    + sz = reserved_pebs * sizeof(struct ubi_eba_tbl_rec);
    + new_ebs = kmalloc(sz, GFP_KERNEL);
    + if (!new_ebs)
    + return -ENOMEM;
    +
    + for (i = 0; i < reserved_pebs; i++) {
    + new_ebs[i].pnum = NOT_MAPPED;
    + new_ebs[i].leb_ver = 0;
    + }
    +
    + idx = vol_id2idx(ubi, vol_id);
    +
    + spin_lock(&ubi->eba.eba_tbl_lock);
    + ubi_assert(eba_tbl[idx].recs);
    +
    + if (reserved_pebs < eba_tbl[idx].leb_count) {
    + min = reserved_pebs;
    + to_put = eba_tbl[idx].leb_count - reserved_pebs;
    + } else {
    + min = eba_tbl[idx].leb_count;
    + to_put = 0;
    + }
    +
    + for (i = 0; i < min; i++) {
    + new_ebs[i].pnum = eba_tbl[idx].recs[i].pnum;
    + new_ebs[i].leb_ver = eba_tbl[idx].recs[i].leb_ver;
    + }
    + spin_unlock(&ubi->eba.eba_tbl_lock);
    +
    + for (i = 0; i < to_put; i++) {
    + err = ubi_eba_unmap_leb(ubi, vol_id, i);
    + if (err)
    + break;
    + }
    +
    + spin_lock(&ubi->eba.eba_tbl_lock);
    + old_ebs = eba_tbl[idx].recs;
    + eba_tbl[idx].recs = new_ebs;
    + eba_tbl[idx].leb_count = reserved_pebs;
    + spin_unlock(&ubi->eba.eba_tbl_lock);
    +
    + kfree(old_ebs);
    + return err;
    +}
    +
    +/**
    + * ltree_lookup - look up the lock tree.
    + *
    + * @eba: the EBA unit description data structure
    + * @vol_id: volume ID of the logical eraseblock to look up
    + * @lnum: the logical eraseblock to look up
    + *
    + * This function returns a pointer to the corresponding
    + * &struct ubi_eba_ltree_entry object if the logical eraseblock is locked and
    + * %NULL if it is not. The @ubi->eba.ltree_lock has to be locked.
    + */
    +static struct ubi_eba_ltree_entry *ltree_lookup(struct ubi_info *ubi,
    + int vol_id, int lnum)
    +{
    + struct rb_node *p;
    +
    + p = ubi->eba.ltree.rb_node;
    + while (p) {
    + struct ubi_eba_ltree_entry *le;
    +
    + le = rb_entry(p, struct ubi_eba_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: the UBI device description object
    + * @vol_id: volume ID of the logical eraseblock
    + * @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 a pointer to the lock tree entry or %-ENOMEM if memory allocation
    + * failed.
    + */
    +static struct ubi_eba_ltree_entry *ltree_add_entry(struct ubi_info *ubi,
    + int vol_id, int lnum)
    +{
    + struct ubi_eba_ltree_entry *le, *le1, *le_free;
    +
    + le = kmem_cache_alloc(eba_ltree_entry_slab, GFP_KERNEL);
    + if (unlikely(!le))
    + return ERR_PTR(-ENOMEM);
    +
    + le->vol_id = vol_id;
    + le->lnum = lnum;
    +
    + spin_lock(&ubi->eba.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->eba.ltree RB-tree.
    + */
    + le_free = NULL;
    +
    + p = &ubi->eba.ltree.rb_node;
    + while (*p) {
    + parent = *p;
    + le1 = rb_entry(parent, struct ubi_eba_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->eba.ltree);
    + }
    + le->users += 1;
    + spin_unlock(&ubi->eba.ltree_lock);
    +
    + if (le_free)
    + kmem_cache_free(eba_ltree_entry_slab, le_free);
    +
    + return le;
    +}
    +
    +/**
    + * leb_read_lock - lock logical eraseblock for reading.
    + *
    + * @ubi: the UBI device description object
    + * @vol_id: volume ID
    + * @lnum: the logical eraseblock to lock
    + *
    + * 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_info *ubi, int vol_id, int lnum)
    +{
    + struct ubi_eba_ltree_entry *le;
    +
    + le = ltree_add_entry(ubi, vol_id, lnum);
    + if (unlikely(IS_ERR(le)))
    + return PTR_ERR(le);
    + down_read(&le->mutex);
    + return 0;
    +}
    +
    +/**
    + * leb_read_unlock - unlock logical eraseblock.
    + *
    + * @ubi: the UBI device description object
    + * @vol_id: volume ID
    + * @lnum: the logical eraseblock to unlock
    + */
    +static void leb_read_unlock(struct ubi_info *ubi, int vol_id, int lnum)
    +{
    + int free = 0;
    + struct ubi_eba_ltree_entry *le;
    +
    + spin_lock(&ubi->eba.ltree_lock);
    + le = ltree_lookup(ubi, vol_id, lnum);
    + le->users -= 1;
    + ubi_assert(le->users >= 0);
    + if (le->users == 0) {
    + rb_erase(&le->rb, &ubi->eba.ltree);
    + free = 1;
    + }
    + spin_unlock(&ubi->eba.ltree_lock);
    +
    + up_read(&le->mutex);
    + if (free)
    + kmem_cache_free(eba_ltree_entry_slab, le);
    +}
    +
    +/**
    + * leb_write_lock - lock logical eraseblock for writing.
    + *
    + * @ubi: the UBI device description object
    + * @vol_id: volume ID
    + * @lnum: the logical eraseblock to lock
    + *
    + * 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_info *ubi, int vol_id, int lnum)
    +{
    + struct ubi_eba_ltree_entry *le;
    +
    + le = ltree_add_entry(ubi, vol_id, lnum);
    + if (unlikely(IS_ERR(le)))
    + return PTR_ERR(le);
    + down_write(&le->mutex);
    + return 0;
    +}
    +
    +/**
    + * leb_write_unlock - unlock logical eraseblock.
    + *
    + * @ubi: the UBI device description object
    + * @vol_id: volume ID
    + * @lnum: the logical eraseblock to unlock
    + */
    +static void leb_write_unlock(struct ubi_info *ubi, int vol_id, int lnum)
    +{
    + int free;
    + struct ubi_eba_ltree_entry *le;
    +
    + spin_lock(&ubi->eba.ltree_lock);
    + le = ltree_lookup(ubi, vol_id, lnum);
    + le->users -= 1;
    + ubi_assert(le->users >= 0);
    + if (le->users == 0) {
    + rb_erase(&le->rb, &ubi->eba.ltree);
    + free = 1;
    + } else
    + free = 0;
    + spin_unlock(&ubi->eba.ltree_lock);
    +
    + up_write(&le->mutex);
    + if (free)
    + kmem_cache_free(eba_ltree_entry_slab, le);
    +}
    +
    +/**
    + * ubi_eba_unmap_leb - un-map a logical eraseblock.
    + *
    + * @ubi: the UBI device description object
    + * @vol_id: volume ID
    + * @lnum: the logical eraseblock to erase
    + *
    + * This function un-maps the logical eraseblock 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_info *ubi, int vol_id, int lnum)
    +{
    + int err, pnum;
    +
    + ubi_assert(vol_id >= 0);
    + ubi_assert(vol_id < ubi->vtbl.vt_slots || ubi_is_ivol(vol_id));
    + ubi_assert(lnum >= 0);
    + ubi_assert(ubi->eba.eba_tbl[vol_id2idx(ubi, vol_id)].recs);
    + ubi_assert(lnum < ubi->eba.eba_tbl[vol_id2idx(ubi, vol_id)].leb_count);
    +
    + cond_resched();
    +
    + if (unlikely(ubi->io.ro_mode)) {
    + dbg_err("read-only mode");
    + return -EROFS;
    + }
    +
    + err = leb_write_lock(ubi, vol_id, lnum);
    + if (unlikely(err))
    + return err;
    +
    + pnum = leb2peb(ubi, vol_id, lnum);
    + if (pnum < 0) {
    + /* This logical eraseblock is already unmapped */
    + dbg_eba("erase LEB %d:%d (unmapped)", vol_id, lnum);
    + goto out_unlock;
    + }
    + dbg_eba("erase LEB %d:%d, PEB %d", vol_id, lnum, pnum);
    +
    + leb_unmap(ubi, vol_id, lnum);
    +
    + err = ubi_wl_put_peb(ubi, pnum, 0);
    +
    +out_unlock:
    + leb_write_unlock(ubi, vol_id, lnum);
    + return err;
    +}
    +
    +/**
    + * ubi_eba_read_leb - read data from a logical eraseblock.
    + *
    + * @ubi: the UBI device description object
    + * @vol_id: volume ID from where to read
    + * @lnum: the logical eraseblock to read from
    + * @buf: buffer to store the read data
    + * @offset: offset within the logical eraseblock 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,
    + * id 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_info *ubi, int vol_id, int lnum, void *buf,
    + int offset, int len, int check)
    +{
    + int err, pnum, scrub = 0;
    + const struct ubi_vtbl_vtr *vtr;
    + uint32_t data_crc;
    + struct ubi_vid_hdr *vid_hdr;
    +
    + ubi_assert(vol_id >= 0);
    + ubi_assert(vol_id < ubi->vtbl.vt_slots || ubi_is_ivol(vol_id));
    + ubi_assert(lnum >= 0);
    + ubi_assert(offset >= 0);
    + ubi_assert(len > 0);
    +
    + vtr = ubi_vtbl_get_vtr(ubi, vol_id);
    + ubi_assert(!IS_ERR(vtr));
    + ubi_assert(offset + len <= ubi->io.leb_size - vtr->data_pad);
    + ubi_assert(lnum < ubi->eba.eba_tbl[vol_id2idx(ubi, vol_id)].leb_count);
    +
    + cond_resched();
    +
    + err = leb_read_lock(ubi, vol_id, lnum);
    + if (unlikely(err))
    + return err;
    +
    + pnum = leb2peb(ubi, vol_id, lnum);
    +
    + if (pnum < 0) {
    + /*
    + * The logical eraseblock is not mapped, fill the whole buffer
    + * by 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(vtr->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 (vtr->vol_type == UBI_DYNAMIC_VOLUME)
    + /* In case of dynamic volumes no checking is needed */
    + check = 0;
    +
    + if (check) {
    + vid_hdr = ubi_zalloc_vid_hdr(ubi);
    + if (unlikely(!vid_hdr)) {
    + err = -ENOMEM;
    + goto out_unlock;
    + }
    +
    + err = ubi_io_read_vid_hdr(ubi, pnum, vid_hdr, 1);
    + if (unlikely(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_VID_HDR) {
    + ubi_warn("bad VID header at PEB %d, LEB"
    + "%d:%d", pnum, vol_id, lnum);
    + err = -EBADMSG;
    + } else
    + ubi_ro_mode(ubi);
    + }
    + goto out_free;
    + } else if (unlikely(err == UBI_IO_BITFLIPS))
    + scrub = 1;
    +
    + err = paranoid_check_leb(ubi, pnum, vol_id, lnum, vid_hdr);
    + if (unlikely(err)) {
    + if (err > 0)
    + err = -EINVAL;
    + goto out_free;
    + }
    +
    + ubi_assert(lnum < ubi32_to_cpu(vid_hdr->used_ebs));
    + ubi_assert(len == ubi32_to_cpu(vid_hdr->data_size));
    +
    + data_crc = ubi32_to_cpu(vid_hdr->data_crc);
    + ubi_free_vid_hdr(ubi, vid_hdr);
    + }
    +
    + err = ubi_io_read_data(ubi, buf, pnum, offset, len);
    + if (unlikely(err) && err != UBI_IO_BITFLIPS)
    + goto out_unlock;
    + else if (unlikely(err == UBI_IO_BITFLIPS)) {
    + scrub = 1;
    + err = 0;
    + }
    +
    + if (check) {
    + uint32_t crc;
    +
    + crc = crc32(UBI_CRC32_INIT, buf, len);
    + if (unlikely(crc != data_crc)) {
    + ubi_warn("CRC error: calculated %#08x, must be %#08x",
    + crc, data_crc);
    + err = -EBADMSG;
    + goto out_unlock;
    + }
    +
    + if (err)
    + dbg_eba("error %d while reading, but data CRC is OK, "
    + "ignore the error", err);
    + err = 0;
    + dbg_eba("data is OK, CRC matches");
    + }
    +
    + if (unlikely(err))
    + goto out_unlock;
    +
    + if (unlikely(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;
    +}
    +
    +/**
    + * recover_peb - recover from write failure.
    + *
    + * @ubi: the 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 a 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
    + * foam 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.
    + */
    +int recover_peb(struct ubi_info *ubi, int pnum, int vol_id, int lnum,
    + const void *buf, int offset, int len)
    +{
    + int err, new_pnum, data_size, tries = 0;
    + struct ubi_vid_hdr *vid_hdr;
    + unsigned char *new_buf;
    +
    + ubi_assert(ubi->io.bad_allowed);
    +
    +retry:
    + new_pnum = ubi_wl_get_peb(ubi, UBI_DATA_UNKNOWN);
    + if (new_pnum < 0)
    + return new_pnum;
    +
    + ubi_msg("recover PEB %d, move data to PEB %d", pnum, new_pnum);
    +
    + /* At first recover the VID header */
    +
    + vid_hdr = ubi_zalloc_vid_hdr(ubi);
    + if (!vid_hdr) {
    + err = -ENOMEM;
    + goto out_put;
    + }
    +
    + err = ubi_io_read_vid_hdr(ubi, pnum, vid_hdr, 1);
    + if (err && err != UBI_IO_BITFLIPS) {
    + if (err > 0)
    + err = -EIO;
    + goto out_free;
    + }
    +
    + vid_hdr->leb_ver = cpu_to_ubi32(ubi32_to_cpu(vid_hdr->leb_ver) + 1);
    + err = ubi_io_write_vid_hdr(ubi, new_pnum, vid_hdr);
    + if (err)
    + goto write_error;
    +
    + /* Now recover the data */
    +
    + data_size = offset + len;
    + new_buf = kmalloc(data_size, GFP_KERNEL);
    + if (unlikely(!new_buf)) {
    + err = -ENOMEM;
    + goto out_free;
    + }
    + memset(new_buf + offset, 0xFF, len);
    +
    + /* Read everything before the area where the write failure happened */
    + if (offset > 0) {
    + err = ubi_io_read_data(ubi, new_buf, pnum, 0, offset);
    + if (err && err != UBI_IO_BITFLIPS) {
    + kfree(new_buf);
    + goto out_free;
    + }
    + }
    +
    + /*
    + * Now we assume that before the failed write the (offset, offset+len)
    + * area contained all 0xFF bytes. This is true for NAND. This is not
    + * always true for NOR, but NOR don't admit of bad PEBs.
    + */
    + memcpy(new_buf + offset, buf, len);
    +
    + err = ubi_io_write_data(ubi, new_buf, new_pnum, 0, data_size);
    + if (err) {
    + kfree(new_buf);
    + goto write_error;
    + }
    +
    + kfree(new_buf);
    + ubi_free_vid_hdr(ubi, vid_hdr);
    + ubi_eba_leb_remap(ubi, vol_id, lnum, new_pnum);
    + ubi_wl_put_peb(ubi, pnum, 1);
    + ubi_msg("data was successfully recovered");
    + return 0;
    +
    +out_free:
    + ubi_free_vid_hdr(ubi, vid_hdr);
    +out_put:
    + ubi_wl_put_peb(ubi, new_pnum, 1);
    + return err;
    +
    +write_error:
    + /*
    + * Bad luck? This physical eraseblock is bad too? Crud. Let's try to
    + * get another one.
    + */
    + ubi_warn("failed to write to PEB %d", new_pnum);
    + ubi_free_vid_hdr(ubi, vid_hdr);
    + ubi_wl_put_peb(ubi, new_pnum, 1);
    + if (++tries > 5)
    + /* We've tried too many times */
    + return err;
    + ubi_msg("try again");
    + goto retry;
    +}
    +
    +/**
    + * ubi_eba_write_leb - write data to logical eraseblock of a dynamic volume.
    + *
    + * @ubi: the UBI device description object
    + * @vol_id: the volume ID where to write
    + * @lnum: the logical eraseblock number to write
    + * @buf: the data to write
    + * @offset: the offset within the logical eraseblock where to write
    + * @len: how many bytes to write
    + * @dtype: data type
    + *
    + * This function writes data to logical eraseblock @lnum of a dynamic volume
    + * @vol_id. Returns zero in case of success and a negative error code in case
    + * of failure. In case of an 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_info *ubi, int vol_id, int lnum,
    + const void *buf, int offset, int len,
    + enum ubi_data_type dtype)
    +{
    + int err, pnum, tries = 0;
    + uint32_t leb_ver;
    + uint64_t sqnum;
    + struct ubi_vid_hdr *vid_hdr;
    + const struct ubi_vtbl_vtr *vtr;
    +
    +retry:
    + ubi_assert(vol_id >= 0);
    + ubi_assert(vol_id < ubi->vtbl.vt_slots || ubi_is_ivol(vol_id));
    + ubi_assert(lnum >= 0);
    + ubi_assert(offset >= 0);
    + ubi_assert(len >= 0);
    + ubi_assert(dtype == UBI_DATA_LONGTERM || dtype == UBI_DATA_SHORTTERM ||
    + dtype == UBI_DATA_UNKNOWN);
    +
    + vtr = ubi_vtbl_get_vtr(ubi, vol_id);
    + ubi_assert(!IS_ERR(vtr));
    + ubi_assert(offset + len <= ubi->io.leb_size - vtr->data_pad);
    + ubi_assert(lnum < ubi->eba.eba_tbl[vol_id2idx(ubi, vol_id)].leb_count);
    + ubi_assert(len % ubi->io.min_io_size == 0);
    + ubi_assert(offset % ubi->io.min_io_size == 0);
    + ubi_assert(vtr->vol_type == UBI_DYNAMIC_VOLUME);
    +
    + cond_resched();
    +
    + if (unlikely(ubi->io.ro_mode)) {
    + dbg_err("read-only mode");
    + return -EROFS;
    + }
    +
    + err = leb_write_lock(ubi, vol_id, lnum);
    + if (unlikely(err))
    + return err;
    +
    + pnum = leb2peb(ubi, vol_id, lnum);
    + if (pnum >= 0) {
    + dbg_eba("write %d bytes at offset %d of LEB %d:%d, PEB %d",
    + len, offset, vol_id, lnum, pnum);
    +
    + if (len != 0) {
    + err = ubi_io_write_data(ubi, buf, pnum, offset, len);
    + if (unlikely(err))
    + goto data_write_error;
    + }
    + 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);
    + if (unlikely(!vid_hdr)) {
    + err = -ENOMEM;
    + goto out_unlock;
    + }
    +
    + sqnum = next_sqnum(ubi);
    + leb_ver = leb_get_ver(ubi, vol_id, lnum);
    +
    + vid_hdr->vol_type = UBI_VID_DYNAMIC;
    + vid_hdr->sqnum = cpu_to_ubi64(sqnum);
    + vid_hdr->leb_ver = cpu_to_ubi32(leb_ver);
    + vid_hdr->vol_id = cpu_to_ubi32(vol_id);
    + vid_hdr->lnum = cpu_to_ubi32(lnum);
    + vid_hdr->compat = ubi_get_compat(ubi, vol_id);
    + vid_hdr->data_pad = cpu_to_ubi32(vtr->data_pad);
    +
    + pnum = ubi_wl_get_peb(ubi, dtype);
    + if (unlikely(pnum < 0)) {
    + err = pnum;
    + ubi_free_vid_hdr(ubi, vid_hdr);
    + goto out_unlock;
    + }
    +
    + 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 (unlikely(err)) {
    + ubi_warn("failed to write VID header to PEB %d", pnum);
    + ubi_free_vid_hdr(ubi, vid_hdr);
    + if (err != -EIO || !ubi->io.bad_allowed)
    + goto no_bad_eraseblocks;
    +
    + /*
    + * Fortunately, we did not write any data there yet, so just put this
    + * physical eraseblock and request a new one. We assume that if this
    + * physical eraseblock went bad, the erase code will handle that.
    + */
    + ubi_msg("try to recover form the error");
    + err = ubi_wl_put_peb(ubi, pnum, 1);
    + leb_write_unlock(ubi, vol_id, lnum);
    + if (err || ++tries > 5) {
    + ubi_ro_mode(ubi);
    + return err;
    + }
    + goto retry;
    + }
    +
    + leb_map(ubi, vol_id, lnum, pnum);
    +
    + if (len != 0) {
    + err = ubi_io_write_data(ubi, buf, pnum, offset, len);
    + if (unlikely(err)) {
    + ubi_free_vid_hdr(ubi, vid_hdr);
    + goto data_write_error;
    + }
    + }
    +
    + leb_write_unlock(ubi, vol_id, lnum);
    + ubi_free_vid_hdr(ubi, vid_hdr);
    + return 0;
    +
    +out_unlock:
    + leb_write_unlock(ubi, vol_id, lnum);
    + return err;
    +
    + /* Failed to write data */
    +data_write_error:
    + ubi_warn("failed to write data to PEB %d", pnum);
    + if (err != -EIO || !ubi->io.bad_allowed)
    + goto no_bad_eraseblocks;
    +
    + 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;
    +
    + /*
    + * This flash device does not admit of bad eraseblocks or something
    + * nasty and unexpected happened. Switch to read-only mode just in
    + * case.
    + */
    +no_bad_eraseblocks:
    + ubi_ro_mode(ubi);
    + leb_write_unlock(ubi, vol_id, lnum);
    + return err;
    +}
    +
    +/**
    + * ubi_eba_write_leb_st - write data to a logical eraseblock of a static
    + * volume.
    + *
    + * @ubi: the UBI device description object
    + * @vol_id: the volume ID where to write
    + * @lnum: the logical eraseblock number to write
    + * @buf: the data to write
    + * @len: how many bytes to write
    + * @dtype: data type
    + * @used_ebs: how many logical eraseblocks will this volume contain (used only
    + * for static volumes)
    + *
    + * This function writes data to a logical eraseblock of a static volume. The
    + * @used_ebs argument should contain total number of logical eraseblock which
    + * will contain any data in this static volume.
    + *
    + * When writing to the last logical eraseblock of a static volume, 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.
    + *
    + * Note, it is prohibited to write more then 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_info *ubi, int vol_id, int lnum,
    + const void *buf, int len, enum ubi_data_type dtype,
    + int used_ebs)
    +{
    + int err, pnum, tries = 0, data_size = len;
    + uint32_t leb_ver, crc;
    + uint64_t sqnum;
    + struct ubi_vid_hdr *vid_hdr;
    + const struct ubi_vtbl_vtr *vtr;
    +
    +retry:
    + ubi_assert(vol_id >= 0);
    + ubi_assert(vol_id < ubi->vtbl.vt_slots || ubi_is_ivol(vol_id));
    + ubi_assert(lnum >= 0);
    + ubi_assert(len > 0);
    + ubi_assert(dtype == UBI_DATA_LONGTERM || dtype == UBI_DATA_SHORTTERM ||
    + dtype == UBI_DATA_UNKNOWN);
    +
    + vtr = ubi_vtbl_get_vtr(ubi, vol_id);
    + ubi_assert(!IS_ERR(vtr));
    + ubi_assert(lnum < ubi->eba.eba_tbl[vol_id2idx(ubi, vol_id)].leb_count);
    + ubi_assert(lnum < used_ebs);
    + ubi_assert(used_ebs >= 0);
    + ubi_assert(vtr->vol_type == UBI_STATIC_VOLUME);
    +
    + cond_resched();
    +
    + if (lnum == used_ebs - 1) {
    + /*
    + * If this is the last logical eraseblock of a static
    + * volume, @len may be unaligned.
    + */
    + ubi_assert(len <= ubi->io.leb_size - vtr->data_pad);
    + len = align_up(data_size, ubi->io.min_io_size);
    + } else {
    + ubi_assert(len == ubi->io.leb_size - vtr->data_pad);
    + ubi_assert(len % ubi->io.min_io_size == 0);
    + }
    +
    + if (unlikely(ubi->io.ro_mode)) {
    + dbg_err("read-only mode");
    + return -EROFS;
    + }
    +
    + err = leb_write_lock(ubi, vol_id, lnum);
    + if (unlikely(err))
    + return err;
    +
    + ubi_assert(leb2peb(ubi, vol_id, lnum) < 0);
    +
    + /*
    + * Get a free physical eraseblock and write the volume identifier
    + * header.
    + */
    + vid_hdr = ubi_zalloc_vid_hdr(ubi);
    + if (unlikely(!vid_hdr)) {
    + err = -ENOMEM;
    + goto out_unlock;
    + }
    +
    + sqnum = next_sqnum(ubi);
    + leb_ver = leb_get_ver(ubi, vol_id, lnum);
    +
    + vid_hdr->sqnum = cpu_to_ubi64(sqnum);
    + vid_hdr->leb_ver = cpu_to_ubi32(leb_ver);
    + vid_hdr->vol_id = cpu_to_ubi32(vol_id);
    + vid_hdr->lnum = cpu_to_ubi32(lnum);
    + vid_hdr->compat = ubi_get_compat(ubi, vol_id);
    + vid_hdr->data_pad = cpu_to_ubi32(vtr->data_pad);
    +
    + crc = crc32(UBI_CRC32_INIT, buf, data_size);
    + vid_hdr->vol_type = UBI_VID_STATIC;
    + vid_hdr->data_size = cpu_to_ubi32(data_size);
    + vid_hdr->used_ebs = cpu_to_ubi32(used_ebs);
    + vid_hdr->data_crc = cpu_to_ubi32(crc);
    +
    + pnum = ubi_wl_get_peb(ubi, dtype);
    + if (unlikely(pnum < 0)) {
    + err = pnum;
    + ubi_free_vid_hdr(ubi, vid_hdr);
    + goto out_unlock;
    + }
    +
    + dbg_eba("write VID hdr and %d bytes at of LEB %d:%d, PEB %d",
    + len, vol_id, lnum, pnum);
    +
    + err = ubi_io_write_vid_hdr(ubi, pnum, vid_hdr);
    + if (unlikely(err)) {
    + ubi_warn("failed to write VID header to PEB %d", pnum);
    + goto write_error;
    + }
    +
    + leb_map(ubi, vol_id, lnum, pnum);
    +
    + err = ubi_io_write_data(ubi, buf, pnum, 0, len);
    + if (unlikely(err)) {
    + ubi_warn("failed to write data to PEB %d", pnum);
    + goto write_error;
    + }
    +
    + leb_write_unlock(ubi, vol_id, lnum);
    + ubi_free_vid_hdr(ubi, vid_hdr);
    + return 0;
    +
    +out_unlock:
    + leb_write_unlock(ubi, vol_id, lnum);
    + return err;
    +
    + /* Write failure */
    +write_error:
    + ubi_free_vid_hdr(ubi, vid_hdr);
    + ubi_free_vid_hdr(ubi, vid_hdr);
    + if (err != -EIO || !ubi->io.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);
    + return err;
    + }
    +
    + /*
    + * We assume that if this physical eraseblock went bad - the erase code
    + * will handle that.
    + */
    + ubi_msg("try to recover form the error");
    + err = ubi_wl_put_peb(ubi, pnum, 1);
    + leb_write_unlock(ubi, vol_id, lnum);
    + if (err || ++tries > 5) {
    + ubi_ro_mode(ubi);
    + return err;
    + }
    + goto retry;
    +}
    +
    +/**
    + * ubi_eba_leb_is_mapped - check if a logical eraseblock is mapped.
    + *
    + * @ubi: the UBI device description object
    + * @vol_id: volume ID
    + * @lnum: the logical eraseblock to check
    + *
    + * This function checks if logical eraseblock @lnum is mapped to a physical
    + * eraseblock. Returns %1 if it is mapped, and %0 if not.
    + */
    +int ubi_eba_leb_is_mapped(struct ubi_info *ubi, int vol_id, int lnum)
    +{
    + dbg_eba("check LEB %d:%d PEBs", vol_id, lnum);
    +
    + ubi_assert(vol_id >= 0 && vol_id < ubi->vtbl.vt_slots);
    + ubi_assert(lnum >= 0);
    + ubi_assert(lnum < ubi->eba.eba_tbl[vol_id2idx(ubi, vol_id)].leb_count);
    +
    + return leb2peb(ubi, vol_id, lnum) >= 0;
    +}
    +
    +/**
    + * ubi_eba_leb_remap - re-map a logical eraseblock to another physical
    + * eraseblock.
    + *
    + * @ubi: the UBI device description object
    + * @vol_id: the volume ID
    + * @lnum: the logical eraseblock number
    + * @pnum: new physical eraseblock to map to
    + *
    + * The logical eraseblock must be locked before re-mapping.
    + */
    +void ubi_eba_leb_remap(struct ubi_info *ubi, int vol_id, int lnum, int pnum)
    +{
    + /* The logical eraseblock is supposed to be locked */
    + paranoid_check_leb_locked(ubi, vol_id, lnum);
    + leb_unmap(ubi, vol_id, lnum);
    + leb_map(ubi, vol_id, lnum, pnum);
    +}
    +
    +/**
    + * build_eba_tbl - build the eraseblock association table.
    + *
    + * @ubi: the UBI device description object
    + * @si: scanning info
    + *
    + * This function returns zero in case of success and a negative error code in
    + * case of failure.
    + */
    +static int build_eba_tbl(const struct ubi_info *ubi,
    + const struct ubi_scan_info *si)
    +{
    + int i, err, idx;
    + struct ubi_eba_tbl_volume *eba_tbl = ubi->eba.eba_tbl;
    +
    + for (idx = 0; idx < ubi->eba.num_volumes; idx++) {
    + struct rb_node *rb;
    + struct ubi_scan_leb *seb;
    + struct ubi_scan_volume *sv;
    + const struct ubi_vtbl_vtr *vtr;
    + int sz;
    +
    + cond_resched();
    +
    + vtr = ubi_vtbl_get_vtr(ubi, idx2vol_id(ubi, idx));
    + if (IS_ERR(vtr))
    + continue;
    +
    + dbg_eba("found volume %d (idx %d)", idx2vol_id(ubi, idx), idx);
    +
    + eba_tbl[idx].leb_count = vtr->reserved_pebs;
    +
    + sz = vtr->reserved_pebs * sizeof(struct ubi_eba_tbl_rec);
    + eba_tbl[idx].recs = kmalloc(sz, GFP_KERNEL);
    + if (unlikely(!eba_tbl[idx].recs)) {
    + err = -ENOMEM;
    + goto out;
    + }
    +
    + for (i = 0; i < vtr->reserved_pebs; i++) {
    + ubi->eba.eba_tbl[idx].recs[i].pnum = NOT_MAPPED;
    + ubi->eba.eba_tbl[idx].recs[i].leb_ver = 0;
    + }
    +
    + sv = ubi_scan_find_sv(si, idx2vol_id(ubi, idx));
    + if (!sv)
    + continue;
    +
    + rb_for_each_entry(rb, seb, &sv->root, u.rb) {
    + ubi->eba.eba_tbl[idx].recs[seb->lnum].pnum = seb->pnum;
    + ubi->eba.eba_tbl[idx].recs[seb->lnum].leb_ver
    + = seb->leb_ver + 100;
    + }
    + }
    +
    + return 0;
    +
    +out:
    + for (i = 0; i < ubi->eba.num_volumes; i++)
    + kfree(ubi->eba.eba_tbl[i].recs);
    +
    + return err;
    +}
    +
    +/**
    + * ltree_entry_ctor - lock tree entries slab cache constructor.
    + *
    + * @obj: the lock-tree entry to construct
    + * @cache: the lock tree entry slab cache
    + * @flag: constructor flags
    + */
    +static void ltree_entry_ctor(void *obj, struct kmem_cache *cache,
    + unsigned long flags)
    +{
    + struct ubi_eba_ltree_entry *le = obj;
    +
    + if ((flags & (SLAB_CTOR_VERIFY | SLAB_CTOR_CONSTRUCTOR)) !=
    + SLAB_CTOR_CONSTRUCTOR)
    + return;
    +
    + le->users = 0;
    + init_rwsem(&le->mutex);
    +}
    +
    +/**
    + * ubi_eba_init_scan - initialize the EBA unit using scanning information.
    + *
    + * @ubi: the UBI device description object
    + * @si: pointer to the scanning information
    + *
    + * This function returns zero in case of success and a negative error code in
    + * case of failure.
    + */
    +int ubi_eba_init_scan(struct ubi_info *ubi, struct ubi_scan_info *si)
    +{
    + int err, sz;
    +
    + dbg_eba("initialize the EBA unit");
    +
    + spin_lock_init(&ubi->eba.eba_tbl_lock);
    + spin_lock_init(&ubi->eba.ltree_lock);
    + ubi->eba.ltree = RB_ROOT;
    +
    + if (ubis_num == 0) {
    + eba_ltree_entry_slab =
    + kmem_cache_create("ubi_eba_ltree_entry_slab",
    + sizeof(struct ubi_eba_ltree_entry), 0,
    + 0, &ltree_entry_ctor, NULL);
    + if (!eba_ltree_entry_slab)
    + return -ENOMEM;
    + }
    +
    + ubi->eba.global_sq_cnt = si->max_sqnum;
    +
    + ubi->eba.num_volumes = ubi->vtbl.vt_slots + UBI_INT_VOL_COUNT;
    + sz = ubi->eba.num_volumes * sizeof(struct ubi_eba_tbl_volume);
    + ubi->eba.eba_tbl = kzalloc(sz, GFP_KERNEL);
    + if (!ubi->eba.eba_tbl)
    + goto out;
    +
    + err = build_eba_tbl(ubi, si);
    + if (err)
    + goto out;
    +
    + dbg_eba("the EBA unit is initialized");
    + return 0;
    +
    +out:
    + kfree(ubi->eba.eba_tbl);
    + if (ubis_num == 0)
    + kmem_cache_destroy(eba_ltree_entry_slab);
    + return err;
    +}
    +
    +/**
    + * ubi_eba_close - close the EBA unit.
    + *
    + * @ubi: the UBI device description object
    + */
    +void ubi_eba_close(const struct ubi_info *ubi)
    +{
    + unsigned int i;
    +
    + dbg_eba("close EBA management unit");
    +
    + for (i = 0; i < ubi->eba.num_volumes; i++)
    + kfree(ubi->eba.eba_tbl[i].recs);
    + if (ubis_num == 1)
    + kmem_cache_destroy(eba_ltree_entry_slab);
    +}
    +
    +/**
    + * ubi_eba_copy_leb - copy logical eraseblock.
    + *
    + * @ubi: the UBI device description object
    + * @from: physical eraseblock number from where to move
    + * @to: physical eraseblock number where to move
    + * @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 zero in case of success, %UBI_IO_BITFLIPS if the operation
    + * was canceled because bit-flips were detected at the target PEB, and a
    + * negative error code in case of failure.
    + */
    +int ubi_eba_copy_leb(struct ubi_info *ubi, int from, int to,
    + struct ubi_vid_hdr *vid_hdr)
    +{
    + int err, vol_id, lnum, data_size, aldata_size, pnum;
    + uint32_t crc;
    + unsigned long long sqnum;
    + void *buf;
    +
    + vol_id = ubi32_to_cpu(vid_hdr->vol_id);
    + lnum = ubi32_to_cpu(vid_hdr->lnum);
    +
    + dbg_eba("copy LEB %d:%d, PEB %d to PEB %d",
    + vol_id, lnum, from, to);
    +
    + if (vid_hdr->vol_type == UBI_VID_STATIC) {
    + data_size = ubi32_to_cpu(vid_hdr->data_size);
    + aldata_size = align_up(data_size, ubi->io.min_io_size);
    + } else
    + data_size = aldata_size =
    + ubi->io.leb_size - ubi32_to_cpu(vid_hdr->data_pad);
    +
    + ubi_assert(aldata_size % ubi->io.min_io_size == 0);
    +
    + buf = kmalloc(aldata_size, GFP_KERNEL);
    + if (unlikely(!buf))
    + return -ENOMEM;
    +
    + /*
    + * We do not want anybody to write to this logical eraseblock while we
    + * are moving it, so we lock it.
    + */
    + err = leb_write_lock(ubi, vol_id, lnum);
    + if (unlikely(err))
    + goto out_free;
    +
    + /*
    + * But the logical eraseblock might have been put by this time.
    + * Cancel if it is true.
    + */
    + pnum = leb2peb(ubi, vol_id, lnum);
    + if (pnum != from) {
    + dbg_eba("LEB %d:%d is no longer mapped to PEB %d, mapped to "
    + "PEB %d, cancel", vol_id, lnum, from, pnum);
    + goto out_unlock;
    + }
    +
    + /*
    + * OK, now the LEB is locked and we can safely start moving it.
    + */
    +
    + dbg_eba("read %d bytes of data", aldata_size);
    +
    + err = ubi_io_read_data(ubi, buf, from, 0, aldata_size);
    + if (unlikely(err) && err != UBI_IO_BITFLIPS) {
    + ubi_warn("error %d while reading data from PEB %d",
    + err, from);
    + goto out_unlock;
    + }
    +
    + /*
    + * Now we have got to calculate how much data we have to 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, buf, data_size);
    +
    + cond_resched();
    + crc = crc32(UBI_CRC32_INIT, buf, data_size);
    + cond_resched();
    +
    + /*
    + * It may turn out 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 (likely(data_size > 0)) {
    + vid_hdr->copy_flag = 1;
    + vid_hdr->data_size = cpu_to_ubi32(data_size);
    + vid_hdr->data_crc = cpu_to_ubi32(crc);
    + }
    + vid_hdr->leb_ver = cpu_to_ubi32(ubi32_to_cpu(vid_hdr->leb_ver) + 1);
    + sqnum = next_sqnum(ubi);
    + vid_hdr->sqnum = cpu_to_ubi64(sqnum);
    +
    + err = ubi_io_write_vid_hdr(ubi, to, vid_hdr);
    + if (unlikely(err))
    + goto out_unlock;
    +
    + 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 (unlikely(err)) {
    + if (err != UBI_IO_BITFLIPS)
    + ubi_warn("cannot read VID header back from PEB %d", to);
    + goto out_unlock;
    + }
    +
    + if (likely(data_size > 0)) {
    + void *buf1;
    +
    + err = ubi_io_write_data(ubi, buf, to, 0, aldata_size);
    + if (unlikely(err))
    + goto out_unlock;
    +
    + /*
    + * We've written the data and are going to read it back to make
    + * sure it was written correctly.
    + */
    + buf1 = kmalloc(aldata_size, GFP_KERNEL);
    + if (unlikely(!buf1)) {
    + err = -ENOMEM;
    + goto out_unlock;
    + }
    +
    + cond_resched();
    +
    + err = ubi_io_read_data(ubi, buf1, to, 0, aldata_size);
    + if (unlikely(err)) {
    + kfree(buf1);
    + if (err != UBI_IO_BITFLIPS)
    + ubi_warn("cannot read data back from PEB %d",
    + to);
    + goto out_unlock;
    + }
    +
    + cond_resched();
    +
    + if (unlikely(memcmp(buf, buf1, aldata_size))) {
    + ubi_warn("read data back from PEB %d - it is different",
    + to);
    + kfree(buf1);
    + goto out_unlock;
    + }
    + kfree(buf1);
    + }
    +
    + ubi_eba_leb_remap(ubi, vol_id, lnum, to);
    + leb_write_unlock(ubi, vol_id, lnum);
    + kfree(buf);
    +
    + return 0;
    +
    +out_unlock:
    + leb_write_unlock(ubi, vol_id, lnum);
    +out_free:
    + kfree(buf);
    + return err;
    +}
    +
    +#ifdef CONFIG_MTD_UBI_DEBUG_PARANOID_EBA
    +
    +/**
    + * paranoid_check_leb - check that a logical eraseblock has correct erase
    + * counter and volume identifier headers.
    + *
    + * @ubi: the UBI device description object
    + * @pnum: the physical eraseblock number
    + * @vol_id: the volume ID to check
    + * @lnum: the logical eraseblock number to check
    + * @vid_hdr: volume identifier header to check
    + *
    + * This function returns zero if the headers are all right, %1 if not, and a
    + * negative error code in case of error.
    + */
    +static int paranoid_check_leb(const struct ubi_info *ubi, int pnum, int vol_id,
    + int lnum, const struct ubi_vid_hdr *vid_hdr)
    +{
    + int err, hdr_vol_id, hdr_lnum;
    + struct ubi_ec_hdr *ec_hdr;
    +
    + /* Check the EC header */
    + ec_hdr = kzalloc(ubi->io.ec_hdr_alsize, GFP_KERNEL);
    + if (unlikely(!ec_hdr))
    + return -ENOMEM;
    +
    + err = ubi_io_read_ec_hdr(ubi, pnum, ec_hdr, 1);
    + kfree(ec_hdr);
    + if (unlikely(err) && err != UBI_IO_BITFLIPS) {
    + if (err < 0)
    + return err;
    + goto fail;
    + }
    +
    + hdr_vol_id = ubi32_to_cpu(vid_hdr->vol_id);
    + hdr_lnum = ubi32_to_cpu(vid_hdr->lnum);
    +
    + if (unlikely(vol_id != hdr_vol_id)) {
    + ubi_err("bad vol_id %d, should be %d", hdr_vol_id, vol_id);
    + goto fail;
    + }
    +
    + if (unlikely(lnum != hdr_lnum)) {
    + ubi_err("bad lnum %d, should be %d", hdr_lnum, lnum);
    + goto fail;
    + }
    +
    + return 0;
    +
    +fail:
    + ubi_err("paranoid check failed");
    + ubi_dbg_dump_stack();
    + return 1;
    +}
    +
    +/**
    + * paranoid_check_leb_locked - ensure that a logical eraseblock is locked.
    + *
    + * @ubi: the UBI device description object
    + * @vol_id: the volume ID to check
    + * @lnum: the logical eraseblock number to check
    + *
    + * This function returns zero if the logical eraseblock is locked and %1 if
    + * not.
    + */
    +static int paranoid_check_leb_locked(struct ubi_info *ubi, int vol_id, int lnum)
    +{
    + struct ubi_eba_ltree_entry *le;
    +
    + spin_lock(&ubi->eba.ltree_lock);
    + le = ltree_lookup(ubi, vol_id, lnum);
    + spin_unlock(&ubi->eba.ltree_lock);
    + if (likely(le))
    + return 0;
    +
    + ubi_err("paranoid check failed");
    + ubi_dbg_dump_stack();
    + return 1;
    +}
    +
    +#endif /* CONFIG_MTD_UBI_DEBUG_PARANOID_EBA */
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      Last update: 2007-03-14 16:27    [W:3.117 / U:0.340 seconds]
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