linux/drivers/mtd/ubi/eba.c
Richard Weinberger 36a87e44f6 UBI: Fastmap: Fix race in ubi_eba_atomic_leb_change()
This function a) requests a new PEB, b) writes data to it,
c) returns the old PEB and d) registers the new PEB in the EBA table.

For the non-fastmap case this works perfectly fine and is powercut safe.
Is fastmap enabled this can lead to issues.
If a new fastmap is written between a) and c) the freshly requested PEB
is no longer in a pool and will not be scanned upon attaching.
If now a powercut happens between c) and d) the freshly requested PEB
will not be scanned and the old one got already scheduled for erase.
After attaching the EBA table will point to a erased PEB.

Fix this issue by swapping steps c) and d).

Signed-off-by: Richard Weinberger <richard@nod.at>
2015-03-26 22:45:58 +01:00

1466 lines
40 KiB
C

/*
* 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_sem);
vol->eba_tbl[lnum] = UBI_LEB_UNMAPPED;
up_read(&ubi->fm_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);
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;
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)
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)
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);
goto write_error;
}
mutex_unlock(&ubi->buf_mutex);
ubi_free_vid_hdr(ubi, vid_hdr);
down_read(&ubi->fm_sem);
vol->eba_tbl[lnum] = new_pnum;
up_read(&ubi->fm_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);
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);
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);
goto write_error;
}
}
down_read(&ubi->fm_sem);
vol->eba_tbl[lnum] = pnum;
up_read(&ubi->fm_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);
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);
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);
goto write_error;
}
ubi_assert(vol->eba_tbl[lnum] < 0);
down_read(&ubi->fm_sem);
vol->eba_tbl[lnum] = pnum;
up_read(&ubi->fm_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;
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);
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);
goto write_error;
}
down_read(&ubi->fm_sem);
old_pnum = vol->eba_tbl[lnum];
vol->eba_tbl[lnum] = pnum;
up_read(&ubi->fm_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_sem);
vol->eba_tbl[lnum] = to;
up_read(&ubi->fm_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;
}