/*
* 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.
*/
static unsigned long long 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);
vol->eba_tbl[lnum] = UBI_LEB_UNMAPPED;
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.
* @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("corrupted VID header at PEB "
"%d, LEB %d:%d", pnum, vol_id,
lnum);
err = -EBADMSG;
} else
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;
err = 0;
} else if (err == -EBADMSG) {
if (vol->vol_type == UBI_DYNAMIC_VOLUME)
goto out_unlock;
scrub = 1;
if (!check) {
ubi_msg("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("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;
}
/**
* 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, UBI_UNKNOWN);
if (new_pnum < 0) {
ubi_free_vid_hdr(ubi, vid_hdr);
return new_pnum;
}
ubi_msg("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;
goto out_put;
}
vid_hdr->sqnum = cpu_to_be64(next_sqnum(ubi));
err = ubi_io_write_vid_hdr(ubi, new_pnum, vid_hdr);
if (err)
goto write_error;
data_size = offset + len;
mutex_lock(&ubi->buf_mutex);
memset(ubi->peb_buf1 + offset, 0xFF, len);
/* Read everything before the area where the write failure happened */
if (offset > 0) {
err = ubi_io_read_data(ubi, ubi->peb_buf1, pnum, 0, offset);
if (err && err != UBI_IO_BITFLIPS)
goto out_unlock;
}
memcpy(ubi->peb_buf1 + offset, buf, len);
err = ubi_io_write_data(ubi, ubi->peb_buf1, new_pnum, 0, data_size);
if (err) {
mutex_unlock(&ubi->buf_mutex);
goto write_error;
}
mutex_unlock(&ubi->buf_mutex);
ubi_free_vid_hdr(ubi, vid_hdr);
vol->eba_tbl[lnum] = new_pnum;
ubi_wl_put_peb(ubi, pnum, 1);
ubi_msg("data was successfully recovered");
return 0;
out_unlock:
mutex_unlock(&ubi->buf_mutex);
out_put:
ubi_wl_put_peb(ubi, 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("failed to write to PEB %d", new_pnum);
ubi_wl_put_peb(ubi, new_pnum, 1);
if (++tries > UBI_IO_RETRIES) {
ubi_free_vid_hdr(ubi, vid_hdr);
return err;
}
ubi_msg("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
* @dtype: data type
*
* 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 dtype)
{
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("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(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, dtype);
if (pnum < 0) {
ubi_free_vid_hdr(ubi, vid_hdr);
leb_write_unlock(ubi, vol_id, lnum);
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("failed to write VID header to LEB %d:%d, PEB %d",
vol_id, lnum, pnum);
goto write_error;
}
if (len) {
err = ubi_io_write_data(ubi, buf, pnum, offset, len);
if (err) {
ubi_warn("failed to write %d bytes at offset %d of "
"LEB %d:%d, PEB %d", len, offset, vol_id,
lnum, pnum);
goto write_error;
}
}
vol->eba_tbl[lnum] = pnum;
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, 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(next_sqnum(ubi));
ubi_msg("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
* @dtype: data type
* @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 dtype,
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(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, dtype);
if (pnum < 0) {
ubi_free_vid_hdr(ubi, vid_hdr);
leb_write_unlock(ubi, vol_id, lnum);
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("failed to write VID header to LEB %d:%d, PEB %d",
vol_id, lnum, pnum);
goto write_error;
}
err = ubi_io_write_data(ubi, buf, pnum, 0, len);
if (err) {
ubi_warn("failed to write %d bytes of data to PEB %d",
len, pnum);
goto write_error;
}
ubi_assert(vol->eba_tbl[lnum] < 0);
vol->eba_tbl[lnum] = pnum;
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, 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(next_sqnum(ubi));
ubi_msg("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
* @dtype: data type
*
* 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 dtype)
{
int err, 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, dtype);
}
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(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, dtype);
if (pnum < 0) {
err = pnum;
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("failed to write VID header to LEB %d:%d, PEB %d",
vol_id, lnum, pnum);
goto write_error;
}
err = ubi_io_write_data(ubi, buf, pnum, 0, len);
if (err) {
ubi_warn("failed to write %d bytes of data to PEB %d",
len, pnum);
goto write_error;
}
if (vol->eba_tbl[lnum] >= 0) {
err = ubi_wl_put_peb(ubi, vol->eba_tbl[lnum], 0);
if (err)
goto out_leb_unlock;
}
vol->eba_tbl[lnum] = pnum;
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, pnum, 1);
if (err || ++tries > UBI_IO_RETRIES) {
ubi_ro_mode(ubi);
goto out_leb_unlock;
}
vid_hdr->sqnum = cpu_to_be64(next_sqnum(ubi));
ubi_msg("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_CANCEL_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_buf1 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_buf1, from, 0, aldata_size);
if (err && err != UBI_IO_BITFLIPS) {
ubi_warn("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_buf1, data_size);
cond_resched();
crc = crc32(UBI_CRC32_INIT, ubi->peb_buf1, 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(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("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_CANCEL_BITFLIPS;
goto out_unlock_buf;
}
if (data_size > 0) {
err = ubi_io_write_data(ubi, ubi->peb_buf1, 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.
*/
err = ubi_io_read_data(ubi, ubi->peb_buf2, to, 0, aldata_size);
if (err) {
if (err != UBI_IO_BITFLIPS) {
ubi_warn("error %d while reading data back "
"from PEB %d", err, to);
if (is_error_sane(err))
err = MOVE_TARGET_RD_ERR;
} else
err = MOVE_CANCEL_BITFLIPS;
goto out_unlock_buf;
}
cond_resched();
if (memcmp(ubi->peb_buf1, ubi->peb_buf2, aldata_size)) {
ubi_warn("read data back from PEB %d and it is "
"different", to);
err = -EINVAL;
goto out_unlock_buf;
}
}
ubi_assert(vol->eba_tbl[lnum] == from);
vol->eba_tbl[lnum] = to;
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_scan()' 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_scan_info *si)
{
/*
* The 1 << 18 (256KiB) number is picked randomly, just a reasonably
* large number to distinguish between newly flashed and used images.
*/
if (si->max_sqnum > (1 << 18)) {
int min = ubi->beb_rsvd_level / 10;
if (!min)
min = 1;
if (ubi->beb_rsvd_pebs > min)
return;
}
ubi_warn("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("%d PEBs are corrupted and not used",
ubi->corr_peb_count);
}
/**
* ubi_eba_init_scan - initialize the EBA sub-system using scanning information.
* @ubi: UBI device description object
* @si: 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_device *ubi, struct ubi_scan_info *si)
{
int i, j, err, num_volumes;
struct ubi_scan_volume *sv;
struct ubi_volume *vol;
struct ubi_scan_leb *seb;
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 = si->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;
sv = ubi_scan_find_sv(si, idx2vol_id(ubi, i));
if (!sv)
continue;
ubi_rb_for_each_entry(rb, seb, &sv->root, u.rb) {
if (seb->lnum >= vol->reserved_pebs)
/*
* This may happen in case of an unclean reboot
* during re-size.
*/
ubi_scan_move_to_list(sv, seb, &si->erase);
vol->eba_tbl[seb->lnum] = seb->pnum;
}
}
if (ubi->avail_pebs < EBA_RESERVED_PEBS) {
ubi_err("no enough physical eraseblocks (%d, need %d)",
ubi->avail_pebs, EBA_RESERVED_PEBS);
if (ubi->corr_peb_count)
ubi_err("%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, si);
} 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;
}