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/*
* 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)
*/
/*
* UBI scanning sub-system.
*
* This sub-system is responsible for scanning the flash media, checking UBI
* headers and providing complete information about the UBI flash image.
*
* The scanning information is represented by a &struct ubi_scan_info' object.
* Information about found volumes is represented by &struct ubi_scan_volume
* objects which are kept in volume RB-tree with root at the @volumes field.
* The RB-tree is indexed by the volume ID.
*
* Scanned logical eraseblocks are represented by &struct ubi_scan_leb objects.
* These objects are kept in per-volume RB-trees with the root at the
* corresponding &struct ubi_scan_volume object. To put it differently, we keep
* an RB-tree of per-volume objects and each of these objects is the root of
* RB-tree of per-eraseblock objects.
*
* Corrupted physical eraseblocks are put to the @corr list, free physical
* eraseblocks are put to the @free list and the physical eraseblock to be
* erased are put to the @erase list.
*
* About corruptions
* ~~~~~~~~~~~~~~~~~
*
* UBI protects EC and VID headers with CRC-32 checksums, so it can detect
* whether the headers are corrupted or not. Sometimes UBI also protects the
* data with CRC-32, e.g., when it executes the atomic LEB change operation, or
* when it moves the contents of a PEB for wear-leveling purposes.
*
* UBI tries to distinguish between 2 types of corruptions.
*
* 1. Corruptions caused by power cuts. These are expected corruptions and UBI
* tries to handle them gracefully, without printing too many warnings and
* error messages. The idea is that we do not lose important data in these case
* - we may lose only the data which was being written to the media just before
* the power cut happened, and the upper layers (e.g., UBIFS) are supposed to
* handle such data losses (e.g., by using the FS journal).
*
* When UBI detects a corruption (CRC-32 mismatch) in a PEB, and it looks like
* the reason is a power cut, UBI puts this PEB to the @erase list, and all
* PEBs in the @erase list are scheduled for erasure later.
*
* 2. Unexpected corruptions which are not caused by power cuts. During
* scanning, such PEBs are put to the @corr list and UBI preserves them.
* Obviously, this lessens the amount of available PEBs, and if at some point
* UBI runs out of free PEBs, it switches to R/O mode. UBI also loudly informs
* about such PEBs every time the MTD device is attached.
*
* However, it is difficult to reliably distinguish between these types of
* corruptions and UBI's strategy is as follows. UBI assumes corruption type 2
* if the VID header is corrupted and the data area does not contain all 0xFFs,
* and there were no bit-flips or integrity errors while reading the data area.
* Otherwise UBI assumes corruption type 1. So the decision criteria are as
* follows.
* o If the data area contains only 0xFFs, there is no data, and it is safe
* to just erase this PEB - this is corruption type 1.
* o If the data area has bit-flips or data integrity errors (ECC errors on
* NAND), it is probably a PEB which was being erased when power cut
* happened, so this is corruption type 1. However, this is just a guess,
* which might be wrong.
* o Otherwise this it corruption type 2.
*/
#include <linux/err.h>
#include <linux/slab.h>
#include <linux/crc32.h>
#include <linux/math64.h>
#include <linux/random.h>
#include "ubi.h"
#ifdef CONFIG_MTD_UBI_DEBUG
static int paranoid_check_si(struct ubi_device *ubi, struct ubi_scan_info *si);
#else
#define paranoid_check_si(ubi, si) 0
#endif
/* Temporary variables used during scanning */
static struct ubi_ec_hdr *ech;
static struct ubi_vid_hdr *vidh;
/**
* add_to_list - add physical eraseblock to a list.
* @si: scanning information
* @pnum: physical eraseblock number to add
* @ec: erase counter of the physical eraseblock
* @to_head: if not zero, add to the head of the list
* @list: the list to add to
*
* This function adds physical eraseblock @pnum to free, erase, or alien lists.
* If @to_head is not zero, PEB will be added to the head of the list, which
* basically means it will be processed first later. E.g., we add corrupted
* PEBs (corrupted due to power cuts) to the head of the erase list to make
* sure we erase them first and get rid of corruptions ASAP. This function
* returns zero in case of success and a negative error code in case of
* failure.
*/
static int add_to_list(struct ubi_scan_info *si, int pnum, int ec, int to_head,
struct list_head *list)
{
struct ubi_scan_leb *seb;
if (list == &si->free) {
dbg_bld("add to free: PEB %d, EC %d", pnum, ec);
} else if (list == &si->erase) {
dbg_bld("add to erase: PEB %d, EC %d", pnum, ec);
} else if (list == &si->alien) {
dbg_bld("add to alien: PEB %d, EC %d", pnum, ec);
si->alien_peb_count += 1;
} else
BUG();
seb = kmem_cache_alloc(si->scan_leb_slab, GFP_KERNEL);
if (!seb)
return -ENOMEM;
seb->pnum = pnum;
seb->ec = ec;
if (to_head)
list_add(&seb->u.list, list);
else
list_add_tail(&seb->u.list, list);
return 0;
}
/**
* add_corrupted - add a corrupted physical eraseblock.
* @si: scanning information
* @pnum: physical eraseblock number to add
* @ec: erase counter of the physical eraseblock
*
* This function adds corrupted physical eraseblock @pnum to the 'corr' list.
* The corruption was presumably not caused by a power cut. Returns zero in
* case of success and a negative error code in case of failure.
*/
static int add_corrupted(struct ubi_scan_info *si, int pnum, int ec)
{
struct ubi_scan_leb *seb;
dbg_bld("add to corrupted: PEB %d, EC %d", pnum, ec);
seb = kmem_cache_alloc(si->scan_leb_slab, GFP_KERNEL);
if (!seb)
return -ENOMEM;
si->corr_peb_count += 1;
seb->pnum = pnum;
seb->ec = ec;
list_add(&seb->u.list, &si->corr);
return 0;
}
/**
* validate_vid_hdr - check volume identifier header.
* @vid_hdr: the volume identifier header to check
* @sv: information about the volume this logical eraseblock belongs to
* @pnum: physical eraseblock number the VID header came from
*
* This function checks that data stored in @vid_hdr is consistent. Returns
* non-zero if an inconsistency was found and zero if not.
*
* Note, UBI does sanity check of everything it reads from the flash media.
* Most of the checks are done in the I/O sub-system. Here we check that the
* information in the VID header is consistent to the information in other VID
* headers of the same volume.
*/
static int validate_vid_hdr(const struct ubi_vid_hdr *vid_hdr,
const struct ubi_scan_volume *sv, int pnum)
{
int vol_type = vid_hdr->vol_type;
int vol_id = be32_to_cpu(vid_hdr->vol_id);
int used_ebs = be32_to_cpu(vid_hdr->used_ebs);
int data_pad = be32_to_cpu(vid_hdr->data_pad);
if (sv->leb_count != 0) {
int sv_vol_type;
/*
* This is not the first logical eraseblock belonging to this
* volume. Ensure that the data in its VID header is consistent
* to the data in previous logical eraseblock headers.
*/
if (vol_id != sv->vol_id) {
dbg_err("inconsistent vol_id");
goto bad;
}
if (sv->vol_type == UBI_STATIC_VOLUME)
sv_vol_type = UBI_VID_STATIC;
else
sv_vol_type = UBI_VID_DYNAMIC;
if (vol_type != sv_vol_type) {
dbg_err("inconsistent vol_type");
goto bad;
}
if (used_ebs != sv->used_ebs) {
dbg_err("inconsistent used_ebs");
goto bad;
}
if (data_pad != sv->data_pad) {
dbg_err("inconsistent data_pad");
goto bad;
}
}
return 0;
bad:
ubi_err("inconsistent VID header at PEB %d", pnum);
ubi_dbg_dump_vid_hdr(vid_hdr);
ubi_dbg_dump_sv(sv);
return -EINVAL;
}
/**
* add_volume - add volume to the scanning information.
* @si: scanning information
* @vol_id: ID of the volume to add
* @pnum: physical eraseblock number
* @vid_hdr: volume identifier header
*
* If the volume corresponding to the @vid_hdr logical eraseblock is already
* present in the scanning information, this function does nothing. Otherwise
* it adds corresponding volume to the scanning information. Returns a pointer
* to the scanning volume object in case of success and a negative error code
* in case of failure.
*/
static struct ubi_scan_volume *add_volume(struct ubi_scan_info *si, int vol_id,
int pnum,
const struct ubi_vid_hdr *vid_hdr)
{
struct ubi_scan_volume *sv;
struct rb_node **p = &si->volumes.rb_node, *parent = NULL;
ubi_assert(vol_id == be32_to_cpu(vid_hdr->vol_id));
/* Walk the volume RB-tree to look if this volume is already present */
while (*p) {
parent = *p;
sv = rb_entry(parent, struct ubi_scan_volume, rb);
if (vol_id == sv->vol_id)
return sv;
if (vol_id > sv->vol_id)
p = &(*p)->rb_left;
else
p = &(*p)->rb_right;
}
/* The volume is absent - add it */
sv = kmalloc(sizeof(struct ubi_scan_volume), GFP_KERNEL);
if (!sv)
return ERR_PTR(-ENOMEM);
sv->highest_lnum = sv->leb_count = 0;
sv->vol_id = vol_id;
sv->root = RB_ROOT;
sv->used_ebs = be32_to_cpu(vid_hdr->used_ebs);
sv->data_pad = be32_to_cpu(vid_hdr->data_pad);
sv->compat = vid_hdr->compat;
sv->vol_type = vid_hdr->vol_type == UBI_VID_DYNAMIC ? UBI_DYNAMIC_VOLUME
: UBI_STATIC_VOLUME;
if (vol_id > si->highest_vol_id)
si->highest_vol_id = vol_id;
rb_link_node(&sv->rb, parent, p);
rb_insert_color(&sv->rb, &si->volumes);
si->vols_found += 1;
dbg_bld("added volume %d", vol_id);
return sv;
}
/**
* compare_lebs - find out which logical eraseblock is newer.
* @ubi: UBI device description object
* @seb: first logical eraseblock to compare
* @pnum: physical eraseblock number of the second logical eraseblock to
* compare
* @vid_hdr: volume identifier header of the second logical eraseblock
*
* This function compares 2 copies of a LEB and informs which one is newer. In
* case of success this function returns a positive value, in case of failure, a
* negative error code is returned. The success return codes use the following
* bits:
* o bit 0 is cleared: the first PEB (described by @seb) is newer than the
* second PEB (described by @pnum and @vid_hdr);
* o bit 0 is set: the second PEB is newer;
* o bit 1 is cleared: no bit-flips were detected in the newer LEB;
* o bit 1 is set: bit-flips were detected in the newer LEB;
* o bit 2 is cleared: the older LEB is not corrupted;
* o bit 2 is set: the older LEB is corrupted.
*/
static int compare_lebs(struct ubi_device *ubi, const struct ubi_scan_leb *seb,
int pnum, const struct ubi_vid_hdr *vid_hdr)
{
void *buf;
int len, err, second_is_newer, bitflips = 0, corrupted = 0;
uint32_t data_crc, crc;
struct ubi_vid_hdr *vh = NULL;
unsigned long long sqnum2 = be64_to_cpu(vid_hdr->sqnum);
if (sqnum2 == seb->sqnum) {
/*
* This must be a really ancient UBI image which has been
* created before sequence numbers support has been added. At
* that times we used 32-bit LEB versions stored in logical
* eraseblocks. That was before UBI got into mainline. We do not
* support these images anymore. Well, those images still work,
* but only if no unclean reboots happened.
*/
ubi_err("unsupported on-flash UBI format\n");
return -EINVAL;
}
/* Obviously the LEB with lower sequence counter is older */
second_is_newer = !!(sqnum2 > seb->sqnum);
/*
* Now we know which copy is newer. If the copy flag of the PEB with
* newer version is not set, then we just return, otherwise we have to
* check data CRC. For the second PEB we already have the VID header,
* for the first one - we'll need to re-read it from flash.
*
* Note: this may be optimized so that we wouldn't read twice.
*/
if (second_is_newer) {
if (!vid_hdr->copy_flag) {
/* It is not a copy, so it is newer */
dbg_bld("second PEB %d is newer, copy_flag is unset",
pnum);
return 1;
}
} else {
if (!seb->copy_flag) {
/* It is not a copy, so it is newer */
dbg_bld("first PEB %d is newer, copy_flag is unset",
pnum);
return bitflips << 1;
}
vh = ubi_zalloc_vid_hdr(ubi, GFP_KERNEL);
if (!vh)
return -ENOMEM;
pnum = seb->pnum;
err = ubi_io_read_vid_hdr(ubi, pnum, vh, 0);
if (err) {
if (err == UBI_IO_BITFLIPS)
bitflips = 1;
else {
dbg_err("VID of PEB %d header is bad, but it "
"was OK earlier, err %d", pnum, err);
if (err > 0)
err = -EIO;
goto out_free_vidh;
}
}
vid_hdr = vh;
}
/* Read the data of the copy and check the CRC */
len = be32_to_cpu(vid_hdr->data_size);
buf = vmalloc(len);
if (!buf) {
err = -ENOMEM;
goto out_free_vidh;
}
err = ubi_io_read_data(ubi, buf, pnum, 0, len);
if (err && err != UBI_IO_BITFLIPS && !mtd_is_eccerr(err))
goto out_free_buf;
data_crc = be32_to_cpu(vid_hdr->data_crc);
crc = crc32(UBI_CRC32_INIT, buf, len);
if (crc != data_crc) {
dbg_bld("PEB %d CRC error: calculated %#08x, must be %#08x",
pnum, crc, data_crc);
corrupted = 1;
bitflips = 0;
second_is_newer = !second_is_newer;
} else {
dbg_bld("PEB %d CRC is OK", pnum);
bitflips = !!err;
}
vfree(buf);
ubi_free_vid_hdr(ubi, vh);
if (second_is_newer)
dbg_bld("second PEB %d is newer, copy_flag is set", pnum);
else
dbg_bld("first PEB %d is newer, copy_flag is set", pnum);
return second_is_newer | (bitflips << 1) | (corrupted << 2);
out_free_buf:
vfree(buf);
out_free_vidh:
ubi_free_vid_hdr(ubi, vh);
return err;
}
/**
* ubi_scan_add_used - add physical eraseblock to the scanning information.
* @ubi: UBI device description object
* @si: scanning information
* @pnum: the physical eraseblock number
* @ec: erase counter
* @vid_hdr: the volume identifier header
* @bitflips: if bit-flips were detected when this physical eraseblock was read
*
* This function adds information about a used physical eraseblock to the
* 'used' tree of the corresponding volume. The function is rather complex
* because it has to handle cases when this is not the first physical
* eraseblock belonging to the same logical eraseblock, and the newer one has
* to be picked, while the older one has to be dropped. This function returns
* zero in case of success and a negative error code in case of failure.
*/
int ubi_scan_add_used(struct ubi_device *ubi, struct ubi_scan_info *si,
int pnum, int ec, const struct ubi_vid_hdr *vid_hdr,
int bitflips)
{
int err, vol_id, lnum;
unsigned long long sqnum;
struct ubi_scan_volume *sv;
struct ubi_scan_leb *seb;
struct rb_node **p, *parent = NULL;
vol_id = be32_to_cpu(vid_hdr->vol_id);
lnum = be32_to_cpu(vid_hdr->lnum);
sqnum = be64_to_cpu(vid_hdr->sqnum);
dbg_bld("PEB %d, LEB %d:%d, EC %d, sqnum %llu, bitflips %d",
pnum, vol_id, lnum, ec, sqnum, bitflips);
sv = add_volume(si, vol_id, pnum, vid_hdr);
if (IS_ERR(sv))
return PTR_ERR(sv);
if (si->max_sqnum < sqnum)
si->max_sqnum = sqnum;
/*
* Walk the RB-tree of logical eraseblocks of volume @vol_id to look
* if this is the first instance of this logical eraseblock or not.
*/
p = &sv->root.rb_node;
while (*p) {
int cmp_res;
parent = *p;
seb = rb_entry(parent, struct ubi_scan_leb, u.rb);
if (lnum != seb->lnum) {
if (lnum < seb->lnum)
p = &(*p)->rb_left;
else
p = &(*p)->rb_right;
continue;
}
/*
* There is already a physical eraseblock describing the same
* logical eraseblock present.
*/
dbg_bld("this LEB already exists: PEB %d, sqnum %llu, "
"EC %d", seb->pnum, seb->sqnum, seb->ec);
/*
* Make sure that the logical eraseblocks have different
* sequence numbers. Otherwise the image is bad.
*
* However, if the sequence number is zero, we assume it must
* be an ancient UBI image from the era when UBI did not have
* sequence numbers. We still can attach these images, unless
* there is a need to distinguish between old and new
* eraseblocks, in which case we'll refuse the image in
* 'compare_lebs()'. In other words, we attach old clean
* images, but refuse attaching old images with duplicated
* logical eraseblocks because there was an unclean reboot.
*/
if (seb->sqnum == sqnum && sqnum != 0) {
ubi_err("two LEBs with same sequence number %llu",
sqnum);
ubi_dbg_dump_seb(seb, 0);
ubi_dbg_dump_vid_hdr(vid_hdr);
return -EINVAL;
}
/*
* Now we have to drop the older one and preserve the newer
* one.
*/
cmp_res = compare_lebs(ubi, seb, pnum, vid_hdr);
if (cmp_res < 0)
return cmp_res;
if (cmp_res & 1) {
/*
* This logical eraseblock is newer than the one
* found earlier.
*/
err = validate_vid_hdr(vid_hdr, sv, pnum);
if (err)
return err;
err = add_to_list(si, seb->pnum, seb->ec, cmp_res & 4,
&si->erase);
if (err)
return err;
seb->ec = ec;
seb->pnum = pnum;
seb->scrub = ((cmp_res & 2) || bitflips);
seb->copy_flag = vid_hdr->copy_flag;
seb->sqnum = sqnum;
if (sv->highest_lnum == lnum)
sv->last_data_size =
be32_to_cpu(vid_hdr->data_size);
return 0;
} else {
/*
* This logical eraseblock is older than the one found
* previously.
*/
return add_to_list(si, pnum, ec, cmp_res & 4,
&si->erase);
}
}
/*
* We've met this logical eraseblock for the first time, add it to the
* scanning information.
*/
err = validate_vid_hdr(vid_hdr, sv, pnum);
if (err)
return err;
seb = kmem_cache_alloc(si->scan_leb_slab, GFP_KERNEL);
if (!seb)
return -ENOMEM;
seb->ec = ec;
seb->pnum = pnum;
seb->lnum = lnum;
seb->scrub = bitflips;
seb->copy_flag = vid_hdr->copy_flag;
seb->sqnum = sqnum;
if (sv->highest_lnum <= lnum) {
sv->highest_lnum = lnum;
sv->last_data_size = be32_to_cpu(vid_hdr->data_size);
}
sv->leb_count += 1;
rb_link_node(&seb->u.rb, parent, p);
rb_insert_color(&seb->u.rb, &sv->root);
return 0;
}
/**
* ubi_scan_find_sv - find volume in the scanning information.
* @si: scanning information
* @vol_id: the requested volume ID
*
* This function returns a pointer to the volume description or %NULL if there
* are no data about this volume in the scanning information.
*/
struct ubi_scan_volume *ubi_scan_find_sv(const struct ubi_scan_info *si,
int vol_id)
{
struct ubi_scan_volume *sv;
struct rb_node *p = si->volumes.rb_node;
while (p) {
sv = rb_entry(p, struct ubi_scan_volume, rb);
if (vol_id == sv->vol_id)
return sv;
if (vol_id > sv->vol_id)
p = p->rb_left;
else
p = p->rb_right;
}
return NULL;
}
/**
* ubi_scan_find_seb - find LEB in the volume scanning information.
* @sv: a pointer to the volume scanning information
* @lnum: the requested logical eraseblock
*
* This function returns a pointer to the scanning logical eraseblock or %NULL
* if there are no data about it in the scanning volume information.
*/
struct ubi_scan_leb *ubi_scan_find_seb(const struct ubi_scan_volume *sv,
int lnum)
{
struct ubi_scan_leb *seb;
struct rb_node *p = sv->root.rb_node;
while (p) {
seb = rb_entry(p, struct ubi_scan_leb, u.rb);
if (lnum == seb->lnum)
return seb;
if (lnum > seb->lnum)
p = p->rb_left;
else
p = p->rb_right;
}
return NULL;
}
/**
* ubi_scan_rm_volume - delete scanning information about a volume.
* @si: scanning information
* @sv: the volume scanning information to delete
*/
void ubi_scan_rm_volume(struct ubi_scan_info *si, struct ubi_scan_volume *sv)
{
struct rb_node *rb;
struct ubi_scan_leb *seb;
dbg_bld("remove scanning information about volume %d", sv->vol_id);
while ((rb = rb_first(&sv->root))) {
seb = rb_entry(rb, struct ubi_scan_leb, u.rb);
rb_erase(&seb->u.rb, &sv->root);
list_add_tail(&seb->u.list, &si->erase);
}
rb_erase(&sv->rb, &si->volumes);
kfree(sv);
si->vols_found -= 1;
}
/**
* ubi_scan_erase_peb - erase a physical eraseblock.
* @ubi: UBI device description object
* @si: scanning information
* @pnum: physical eraseblock number to erase;
* @ec: erase counter value to write (%UBI_SCAN_UNKNOWN_EC if it is unknown)
*
* This function erases physical eraseblock 'pnum', and writes the erase
* counter header to it. This function should only be used on UBI device
* initialization stages, when the EBA sub-system had not been yet initialized.
* This function returns zero in case of success and a negative error code in
* case of failure.
*/
int ubi_scan_erase_peb(struct ubi_device *ubi, const struct ubi_scan_info *si,
int pnum, int ec)
{
int err;
struct ubi_ec_hdr *ec_hdr;
if ((long long)ec >= UBI_MAX_ERASECOUNTER) {
/*
* Erase counter overflow. Upgrade UBI and use 64-bit
* erase counters internally.
*/
ubi_err("erase counter overflow at PEB %d, EC %d", pnum, ec);
return -EINVAL;
}
ec_hdr = kzalloc(ubi->ec_hdr_alsize, GFP_KERNEL);
if (!ec_hdr)
return -ENOMEM;
ec_hdr->ec = cpu_to_be64(ec);
err = ubi_io_sync_erase(ubi, pnum, 0);
if (err < 0)
goto out_free;
err = ubi_io_write_ec_hdr(ubi, pnum, ec_hdr);
out_free:
kfree(ec_hdr);
return err;
}
/**
* ubi_scan_get_free_peb - get a free physical eraseblock.
* @ubi: UBI device description object
* @si: scanning information
*
* This function returns a free physical eraseblock. It is supposed to be
* called on the UBI initialization stages when the wear-leveling sub-system is
* not initialized yet. This function picks a physical eraseblocks from one of
* the lists, writes the EC header if it is needed, and removes it from the
* list.
*
* This function returns scanning physical eraseblock information in case of
* success and an error code in case of failure.
*/
struct ubi_scan_leb *ubi_scan_get_free_peb(struct ubi_device *ubi,
struct ubi_scan_info *si)
{
int err = 0;
struct ubi_scan_leb *seb, *tmp_seb;
if (!list_empty(&si->free)) {
seb = list_entry(si->free.next, struct ubi_scan_leb, u.list);
list_del(&seb->u.list);
dbg_bld("return free PEB %d, EC %d", seb->pnum, seb->ec);
return seb;
}
/*
* We try to erase the first physical eraseblock from the erase list
* and pick it if we succeed, or try to erase the next one if not. And
* so forth. We don't want to take care about bad eraseblocks here -
* they'll be handled later.
*/
list_for_each_entry_safe(seb, tmp_seb, &si->erase, u.list) {
if (seb->ec == UBI_SCAN_UNKNOWN_EC)
seb->ec = si->mean_ec;
err = ubi_scan_erase_peb(ubi, si, seb->pnum, seb->ec+1);
if (err)
continue;
seb->ec += 1;
list_del(&seb->u.list);
dbg_bld("return PEB %d, EC %d", seb->pnum, seb->ec);
return seb;
}
ubi_err("no free eraseblocks");
return ERR_PTR(-ENOSPC);
}
/**
* check_corruption - check the data area of PEB.
* @ubi: UBI device description object
* @vid_hrd: the (corrupted) VID header of this PEB
* @pnum: the physical eraseblock number to check
*
* This is a helper function which is used to distinguish between VID header
* corruptions caused by power cuts and other reasons. If the PEB contains only
* 0xFF bytes in the data area, the VID header is most probably corrupted
* because of a power cut (%0 is returned in this case). Otherwise, it was
* probably corrupted for some other reasons (%1 is returned in this case). A
* negative error code is returned if a read error occurred.
*
* If the corruption reason was a power cut, UBI can safely erase this PEB.
* Otherwise, it should preserve it to avoid possibly destroying important
* information.
*/
static int check_corruption(struct ubi_device *ubi, struct ubi_vid_hdr *vid_hdr,
int pnum)
{
int err;
mutex_lock(&ubi->buf_mutex);
memset(ubi->peb_buf1, 0x00, ubi->leb_size);
err = ubi_io_read(ubi, ubi->peb_buf1, pnum, ubi->leb_start,
ubi->leb_size);
if (err == UBI_IO_BITFLIPS || mtd_is_eccerr(err)) {
/*
* Bit-flips or integrity errors while reading the data area.
* It is difficult to say for sure what type of corruption is
* this, but presumably a power cut happened while this PEB was
* erased, so it became unstable and corrupted, and should be
* erased.
*/
err = 0;
goto out_unlock;
}
if (err)
goto out_unlock;
if (ubi_check_pattern(ubi->peb_buf1, 0xFF, ubi->leb_size))
goto out_unlock;
ubi_err("PEB %d contains corrupted VID header, and the data does not "
"contain all 0xFF, this may be a non-UBI PEB or a severe VID "
"header corruption which requires manual inspection", pnum);
ubi_dbg_dump_vid_hdr(vid_hdr);
dbg_msg("hexdump of PEB %d offset %d, length %d",
pnum, ubi->leb_start, ubi->leb_size);
ubi_dbg_print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_OFFSET, 32, 1,
ubi->peb_buf1, ubi->leb_size, 1);
err = 1;
out_unlock:
mutex_unlock(&ubi->buf_mutex);
return err;
}
/**
* process_eb - read, check UBI headers, and add them to scanning information.
* @ubi: UBI device description object
* @si: scanning information
* @pnum: the physical eraseblock number
*
* This function returns a zero if the physical eraseblock was successfully
* handled and a negative error code in case of failure.
*/
static int process_eb(struct ubi_device *ubi, struct ubi_scan_info *si,
int pnum)
{
long long uninitialized_var(ec);
int err, bitflips = 0, vol_id, ec_err = 0;
dbg_bld("scan PEB %d", pnum);
/* Skip bad physical eraseblocks */
err = ubi_io_is_bad(ubi, pnum);
if (err < 0)
return err;
else if (err) {
/*
* FIXME: this is actually duty of the I/O sub-system to
* initialize this, but MTD does not provide enough
* information.
*/
si->bad_peb_count += 1;
return 0;
}
err = ubi_io_read_ec_hdr(ubi, pnum, ech, 0);
if (err < 0)
return err;
switch (err) {
case 0:
break;
case UBI_IO_BITFLIPS:
bitflips = 1;
break;
case UBI_IO_FF:
si->empty_peb_count += 1;
return add_to_list(si, pnum, UBI_SCAN_UNKNOWN_EC, 0,
&si->erase);
case UBI_IO_FF_BITFLIPS:
si->empty_peb_count += 1;
return add_to_list(si, pnum, UBI_SCAN_UNKNOWN_EC, 1,
&si->erase);
case UBI_IO_BAD_HDR_EBADMSG:
case UBI_IO_BAD_HDR:
/*
* We have to also look at the VID header, possibly it is not
* corrupted. Set %bitflips flag in order to make this PEB be
* moved and EC be re-created.
*/
ec_err = err;
ec = UBI_SCAN_UNKNOWN_EC;
bitflips = 1;
break;
default:
ubi_err("'ubi_io_read_ec_hdr()' returned unknown code %d", err);
return -EINVAL;
}
if (!ec_err) {
int image_seq;
/* Make sure UBI version is OK */
if (ech->version != UBI_VERSION) {
ubi_err("this UBI version is %d, image version is %d",
UBI_VERSION, (int)ech->version);
return -EINVAL;
}
ec = be64_to_cpu(ech->ec);
if (ec > UBI_MAX_ERASECOUNTER) {
/*
* Erase counter overflow. The EC headers have 64 bits
* reserved, but we anyway make use of only 31 bit
* values, as this seems to be enough for any existing
* flash. Upgrade UBI and use 64-bit erase counters
* internally.
*/
ubi_err("erase counter overflow, max is %d",
UBI_MAX_ERASECOUNTER);
ubi_dbg_dump_ec_hdr(ech);
return -EINVAL;
}
/*
* Make sure that all PEBs have the same image sequence number.
* This allows us to detect situations when users flash UBI
* images incorrectly, so that the flash has the new UBI image
* and leftovers from the old one. This feature was added
* relatively recently, and the sequence number was always
* zero, because old UBI implementations always set it to zero.
* For this reasons, we do not panic if some PEBs have zero
* sequence number, while other PEBs have non-zero sequence
* number.
*/
image_seq = be32_to_cpu(ech->image_seq);
if (!ubi->image_seq && image_seq)
ubi->image_seq = image_seq;
if (ubi->image_seq && image_seq &&
ubi->image_seq != image_seq) {
ubi_err("bad image sequence number %d in PEB %d, "
"expected %d", image_seq, pnum, ubi->image_seq);
ubi_dbg_dump_ec_hdr(ech);
return -EINVAL;
}
}
/* OK, we've done with the EC header, let's look at the VID header */
err = ubi_io_read_vid_hdr(ubi, pnum, vidh, 0);
if (err < 0)
return err;
switch (err) {
case 0:
break;
case UBI_IO_BITFLIPS:
bitflips = 1;
break;
case UBI_IO_BAD_HDR_EBADMSG:
if (ec_err == UBI_IO_BAD_HDR_EBADMSG)
/*
* Both EC and VID headers are corrupted and were read
* with data integrity error, probably this is a bad
* PEB, bit it is not marked as bad yet. This may also
* be a result of power cut during erasure.
*/
si->maybe_bad_peb_count += 1;
case UBI_IO_BAD_HDR:
if (ec_err)
/*
* Both headers are corrupted. There is a possibility
* that this a valid UBI PEB which has corresponding
* LEB, but the headers are corrupted. However, it is
* impossible to distinguish it from a PEB which just
* contains garbage because of a power cut during erase
* operation. So we just schedule this PEB for erasure.
*
* Besides, in case of NOR flash, we deliberately
* corrupt both headers because NOR flash erasure is
* slow and can start from the end.
*/
err = 0;
else
/*
* The EC was OK, but the VID header is corrupted. We
* have to check what is in the data area.
*/
err = check_corruption(ubi, vidh, pnum);
if (err < 0)
return err;
else if (!err)
/* This corruption is caused by a power cut */
err = add_to_list(si, pnum, ec, 1, &si->erase);
else
/* This is an unexpected corruption */
err = add_corrupted(si, pnum, ec);
if (err)
return err;
goto adjust_mean_ec;
case UBI_IO_FF_BITFLIPS:
err = add_to_list(si, pnum, ec, 1, &si->erase);
if (err)
return err;
goto adjust_mean_ec;
case UBI_IO_FF:
if (ec_err)
err = add_to_list(si, pnum, ec, 1, &si->erase);
else
err = add_to_list(si, pnum, ec, 0, &si->free);
if (err)
return err;
goto adjust_mean_ec;
default:
ubi_err("'ubi_io_read_vid_hdr()' returned unknown code %d",
err);
return -EINVAL;
}
vol_id = be32_to_cpu(vidh->vol_id);
if (vol_id > UBI_MAX_VOLUMES && vol_id != UBI_LAYOUT_VOLUME_ID) {
int lnum = be32_to_cpu(vidh->lnum);
/* Unsupported internal volume */
switch (vidh->compat) {
case UBI_COMPAT_DELETE:
ubi_msg("\"delete\" compatible internal volume %d:%d"
" found, will remove it", vol_id, lnum);
err = add_to_list(si, pnum, ec, 1, &si->erase);
if (err)
return err;
return 0;
case UBI_COMPAT_RO:
ubi_msg("read-only compatible internal volume %d:%d"
" found, switch to read-only mode",
vol_id, lnum);
ubi->ro_mode = 1;
break;
case UBI_COMPAT_PRESERVE:
ubi_msg("\"preserve\" compatible internal volume %d:%d"
" found", vol_id, lnum);
err = add_to_list(si, pnum, ec, 0, &si->alien);
if (err)
return err;
return 0;
case UBI_COMPAT_REJECT:
ubi_err("incompatible internal volume %d:%d found",
vol_id, lnum);
return -EINVAL;
}
}
if (ec_err)
ubi_warn("valid VID header but corrupted EC header at PEB %d",
pnum);
err = ubi_scan_add_used(ubi, si, pnum, ec, vidh, bitflips);
if (err)
return err;
adjust_mean_ec:
if (!ec_err) {
si->ec_sum += ec;
si->ec_count += 1;
if (ec > si->max_ec)
si->max_ec = ec;
if (ec < si->min_ec)
si->min_ec = ec;
}
return 0;
}
/**
* check_what_we_have - check what PEB were found by scanning.
* @ubi: UBI device description object
* @si: scanning information
*
* This is a helper function which takes a look what PEBs were found by
* scanning, and decides whether the flash is empty and should be formatted and
* whether there are too many corrupted PEBs and we should not attach this
* MTD device. Returns zero if we should proceed with attaching the MTD device,
* and %-EINVAL if we should not.
*/
static int check_what_we_have(struct ubi_device *ubi, struct ubi_scan_info *si)
{
struct ubi_scan_leb *seb;
int max_corr, peb_count;
peb_count = ubi->peb_count - si->bad_peb_count - si->alien_peb_count;
max_corr = peb_count / 20 ?: 8;
/*
* Few corrupted PEBs is not a problem and may be just a result of
* unclean reboots. However, many of them may indicate some problems
* with the flash HW or driver.
*/
if (si->corr_peb_count) {
ubi_err("%d PEBs are corrupted and preserved",
si->corr_peb_count);
printk(KERN_ERR "Corrupted PEBs are:");
list_for_each_entry(seb, &si->corr, u.list)
printk(KERN_CONT " %d", seb->pnum);
printk(KERN_CONT "\n");
/*
* If too many PEBs are corrupted, we refuse attaching,
* otherwise, only print a warning.
*/
if (si->corr_peb_count >= max_corr) {
ubi_err("too many corrupted PEBs, refusing");
return -EINVAL;
}
}
if (si->empty_peb_count + si->maybe_bad_peb_count == peb_count) {
/*
* All PEBs are empty, or almost all - a couple PEBs look like
* they may be bad PEBs which were not marked as bad yet.
*
* This piece of code basically tries to distinguish between
* the following situations:
*
* 1. Flash is empty, but there are few bad PEBs, which are not
* marked as bad so far, and which were read with error. We
* want to go ahead and format this flash. While formatting,
* the faulty PEBs will probably be marked as bad.
*
* 2. Flash contains non-UBI data and we do not want to format
* it and destroy possibly important information.
*/
if (si->maybe_bad_peb_count <= 2) {
si->is_empty = 1;
ubi_msg("empty MTD device detected");
get_random_bytes(&ubi->image_seq,
sizeof(ubi->image_seq));
} else {
ubi_err("MTD device is not UBI-formatted and possibly "
"contains non-UBI data - refusing it");
return -EINVAL;
}
}
return 0;
}
/**
* ubi_scan - scan an MTD device.
* @ubi: UBI device description object
*
* This function does full scanning of an MTD device and returns complete
* information about it. In case of failure, an error code is returned.
*/
struct ubi_scan_info *ubi_scan(struct ubi_device *ubi)
{
int err, pnum;
struct rb_node *rb1, *rb2;
struct ubi_scan_volume *sv;
struct ubi_scan_leb *seb;
struct ubi_scan_info *si;
si = kzalloc(sizeof(struct ubi_scan_info), GFP_KERNEL);
if (!si)
return ERR_PTR(-ENOMEM);
INIT_LIST_HEAD(&si->corr);
INIT_LIST_HEAD(&si->free);
INIT_LIST_HEAD(&si->erase);
INIT_LIST_HEAD(&si->alien);
si->volumes = RB_ROOT;
err = -ENOMEM;
si->scan_leb_slab = kmem_cache_create("ubi_scan_leb_slab",
sizeof(struct ubi_scan_leb),
0, 0, NULL);
if (!si->scan_leb_slab)
goto out_si;
ech = kzalloc(ubi->ec_hdr_alsize, GFP_KERNEL);
if (!ech)
goto out_slab;
vidh = ubi_zalloc_vid_hdr(ubi, GFP_KERNEL);
if (!vidh)
goto out_ech;
for (pnum = 0; pnum < ubi->peb_count; pnum++) {
cond_resched();
dbg_gen("process PEB %d", pnum);
err = process_eb(ubi, si, pnum);
if (err < 0)
goto out_vidh;
}
dbg_msg("scanning is finished");
/* Calculate mean erase counter */
if (si->ec_count)
si->mean_ec = div_u64(si->ec_sum, si->ec_count);
err = check_what_we_have(ubi, si);
if (err)
goto out_vidh;
/*
* In case of unknown erase counter we use the mean erase counter
* value.
*/
ubi_rb_for_each_entry(rb1, sv, &si->volumes, rb) {
ubi_rb_for_each_entry(rb2, seb, &sv->root, u.rb)
if (seb->ec == UBI_SCAN_UNKNOWN_EC)
seb->ec = si->mean_ec;
}
list_for_each_entry(seb, &si->free, u.list) {
if (seb->ec == UBI_SCAN_UNKNOWN_EC)
seb->ec = si->mean_ec;
}
list_for_each_entry(seb, &si->corr, u.list)
if (seb->ec == UBI_SCAN_UNKNOWN_EC)
seb->ec = si->mean_ec;
list_for_each_entry(seb, &si->erase, u.list)
if (seb->ec == UBI_SCAN_UNKNOWN_EC)
seb->ec = si->mean_ec;
err = paranoid_check_si(ubi, si);
if (err)
goto out_vidh;
ubi_free_vid_hdr(ubi, vidh);
kfree(ech);
return si;
out_vidh:
ubi_free_vid_hdr(ubi, vidh);
out_ech:
kfree(ech);
out_slab:
kmem_cache_destroy(si->scan_leb_slab);
out_si:
ubi_scan_destroy_si(si);
return ERR_PTR(err);
}
/**
* destroy_sv - free the scanning volume information
* @sv: scanning volume information
* @si: scanning information
*
* This function destroys the volume RB-tree (@sv->root) and the scanning
* volume information.
*/
static void destroy_sv(struct ubi_scan_info *si, struct ubi_scan_volume *sv)
{
struct ubi_scan_leb *seb;
struct rb_node *this = sv->root.rb_node;
while (this) {
if (this->rb_left)
this = this->rb_left;
else if (this->rb_right)
this = this->rb_right;
else {
seb = rb_entry(this, struct ubi_scan_leb, u.rb);
this = rb_parent(this);
if (this) {
if (this->rb_left == &seb->u.rb)
this->rb_left = NULL;
else
this->rb_right = NULL;
}
kmem_cache_free(si->scan_leb_slab, seb);
}
}
kfree(sv);
}
/**
* ubi_scan_destroy_si - destroy scanning information.
* @si: scanning information
*/
void ubi_scan_destroy_si(struct ubi_scan_info *si)
{
struct ubi_scan_leb *seb, *seb_tmp;
struct ubi_scan_volume *sv;
struct rb_node *rb;
list_for_each_entry_safe(seb, seb_tmp, &si->alien, u.list) {
list_del(&seb->u.list);
kmem_cache_free(si->scan_leb_slab, seb);
}
list_for_each_entry_safe(seb, seb_tmp, &si->erase, u.list) {
list_del(&seb->u.list);
kmem_cache_free(si->scan_leb_slab, seb);
}
list_for_each_entry_safe(seb, seb_tmp, &si->corr, u.list) {
list_del(&seb->u.list);
kmem_cache_free(si->scan_leb_slab, seb);
}
list_for_each_entry_safe(seb, seb_tmp, &si->free, u.list) {
list_del(&seb->u.list);
kmem_cache_free(si->scan_leb_slab, seb);
}
/* Destroy the volume RB-tree */
rb = si->volumes.rb_node;
while (rb) {
if (rb->rb_left)
rb = rb->rb_left;
else if (rb->rb_right)
rb = rb->rb_right;
else {
sv = rb_entry(rb, struct ubi_scan_volume, rb);
rb = rb_parent(rb);
if (rb) {
if (rb->rb_left == &sv->rb)
rb->rb_left = NULL;
else
rb->rb_right = NULL;
}
destroy_sv(si, sv);
}
}
kmem_cache_destroy(si->scan_leb_slab);
kfree(si);
}
#ifdef CONFIG_MTD_UBI_DEBUG
/**
* paranoid_check_si - check the scanning information.
* @ubi: UBI device description object
* @si: scanning information
*
* This function returns zero if the scanning information is all right, and a
* negative error code if not or if an error occurred.
*/
static int paranoid_check_si(struct ubi_device *ubi, struct ubi_scan_info *si)
{
int pnum, err, vols_found = 0;
struct rb_node *rb1, *rb2;
struct ubi_scan_volume *sv;
struct ubi_scan_leb *seb, *last_seb;
uint8_t *buf;
if (!ubi->dbg->chk_gen)
return 0;
/*
* At first, check that scanning information is OK.
*/
ubi_rb_for_each_entry(rb1, sv, &si->volumes, rb) {
int leb_count = 0;
cond_resched();
vols_found += 1;
if (si->is_empty) {
ubi_err("bad is_empty flag");
goto bad_sv;
}
if (sv->vol_id < 0 || sv->highest_lnum < 0 ||
sv->leb_count < 0 || sv->vol_type < 0 || sv->used_ebs < 0 ||
sv->data_pad < 0 || sv->last_data_size < 0) {
ubi_err("negative values");
goto bad_sv;
}
if (sv->vol_id >= UBI_MAX_VOLUMES &&
sv->vol_id < UBI_INTERNAL_VOL_START) {
ubi_err("bad vol_id");
goto bad_sv;
}
if (sv->vol_id > si->highest_vol_id) {
ubi_err("highest_vol_id is %d, but vol_id %d is there",
si->highest_vol_id, sv->vol_id);
goto out;
}
if (sv->vol_type != UBI_DYNAMIC_VOLUME &&
sv->vol_type != UBI_STATIC_VOLUME) {
ubi_err("bad vol_type");
goto bad_sv;
}
if (sv->data_pad > ubi->leb_size / 2) {
ubi_err("bad data_pad");
goto bad_sv;
}
last_seb = NULL;
ubi_rb_for_each_entry(rb2, seb, &sv->root, u.rb) {
cond_resched();
last_seb = seb;
leb_count += 1;
if (seb->pnum < 0 || seb->ec < 0) {
ubi_err("negative values");
goto bad_seb;
}
if (seb->ec < si->min_ec) {
ubi_err("bad si->min_ec (%d), %d found",
si->min_ec, seb->ec);
goto bad_seb;
}
if (seb->ec > si->max_ec) {
ubi_err("bad si->max_ec (%d), %d found",
si->max_ec, seb->ec);
goto bad_seb;
}
if (seb->pnum >= ubi->peb_count) {
ubi_err("too high PEB number %d, total PEBs %d",
seb->pnum, ubi->peb_count);
goto bad_seb;
}
if (sv->vol_type == UBI_STATIC_VOLUME) {
if (seb->lnum >= sv->used_ebs) {
ubi_err("bad lnum or used_ebs");
goto bad_seb;
}
} else {
if (sv->used_ebs != 0) {
ubi_err("non-zero used_ebs");
goto bad_seb;
}
}
if (seb->lnum > sv->highest_lnum) {
ubi_err("incorrect highest_lnum or lnum");
goto bad_seb;
}
}
if (sv->leb_count != leb_count) {
ubi_err("bad leb_count, %d objects in the tree",
leb_count);
goto bad_sv;
}
if (!last_seb)
continue;
seb = last_seb;
if (seb->lnum != sv->highest_lnum) {
ubi_err("bad highest_lnum");
goto bad_seb;
}
}
if (vols_found != si->vols_found) {
ubi_err("bad si->vols_found %d, should be %d",
si->vols_found, vols_found);
goto out;
}
/* Check that scanning information is correct */
ubi_rb_for_each_entry(rb1, sv, &si->volumes, rb) {
last_seb = NULL;
ubi_rb_for_each_entry(rb2, seb, &sv->root, u.rb) {
int vol_type;
cond_resched();
last_seb = seb;
err = ubi_io_read_vid_hdr(ubi, seb->pnum, vidh, 1);
if (err && err != UBI_IO_BITFLIPS) {
ubi_err("VID header is not OK (%d)", err);
if (err > 0)
err = -EIO;
return err;
}
vol_type = vidh->vol_type == UBI_VID_DYNAMIC ?
UBI_DYNAMIC_VOLUME : UBI_STATIC_VOLUME;
if (sv->vol_type != vol_type) {
ubi_err("bad vol_type");
goto bad_vid_hdr;
}
if (seb->sqnum != be64_to_cpu(vidh->sqnum)) {
ubi_err("bad sqnum %llu", seb->sqnum);
goto bad_vid_hdr;
}
if (sv->vol_id != be32_to_cpu(vidh->vol_id)) {
ubi_err("bad vol_id %d", sv->vol_id);
goto bad_vid_hdr;
}
if (sv->compat != vidh->compat) {
ubi_err("bad compat %d", vidh->compat);
goto bad_vid_hdr;
}
if (seb->lnum != be32_to_cpu(vidh->lnum)) {
ubi_err("bad lnum %d", seb->lnum);
goto bad_vid_hdr;
}
if (sv->used_ebs != be32_to_cpu(vidh->used_ebs)) {
ubi_err("bad used_ebs %d", sv->used_ebs);
goto bad_vid_hdr;
}
if (sv->data_pad != be32_to_cpu(vidh->data_pad)) {
ubi_err("bad data_pad %d", sv->data_pad);
goto bad_vid_hdr;
}
}
if (!last_seb)
continue;
if (sv->highest_lnum != be32_to_cpu(vidh->lnum)) {
ubi_err("bad highest_lnum %d", sv->highest_lnum);
goto bad_vid_hdr;
}
if (sv->last_data_size != be32_to_cpu(vidh->data_size)) {
ubi_err("bad last_data_size %d", sv->last_data_size);
goto bad_vid_hdr;
}
}
/*
* Make sure that all the physical eraseblocks are in one of the lists
* or trees.
*/
buf = kzalloc(ubi->peb_count, GFP_KERNEL);
if (!buf)
return -ENOMEM;
for (pnum = 0; pnum < ubi->peb_count; pnum++) {
err = ubi_io_is_bad(ubi, pnum);
if (err < 0) {
kfree(buf);
return err;
} else if (err)
buf[pnum] = 1;
}
ubi_rb_for_each_entry(rb1, sv, &si->volumes, rb)
ubi_rb_for_each_entry(rb2, seb, &sv->root, u.rb)
buf[seb->pnum] = 1;
list_for_each_entry(seb, &si->free, u.list)
buf[seb->pnum] = 1;
list_for_each_entry(seb, &si->corr, u.list)
buf[seb->pnum] = 1;
list_for_each_entry(seb, &si->erase, u.list)
buf[seb->pnum] = 1;
list_for_each_entry(seb, &si->alien, u.list)
buf[seb->pnum] = 1;
err = 0;
for (pnum = 0; pnum < ubi->peb_count; pnum++)
if (!buf[pnum]) {
ubi_err("PEB %d is not referred", pnum);
err = 1;
}
kfree(buf);
if (err)
goto out;
return 0;
bad_seb:
ubi_err("bad scanning information about LEB %d", seb->lnum);
ubi_dbg_dump_seb(seb, 0);
ubi_dbg_dump_sv(sv);
goto out;
bad_sv:
ubi_err("bad scanning information about volume %d", sv->vol_id);
ubi_dbg_dump_sv(sv);
goto out;
bad_vid_hdr:
ubi_err("bad scanning information about volume %d", sv->vol_id);
ubi_dbg_dump_sv(sv);
ubi_dbg_dump_vid_hdr(vidh);
out:
ubi_dbg_dump_stack();
return -EINVAL;
}
#endif /* CONFIG_MTD_UBI_DEBUG */