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littlefs/bd/lfs_emubd.c
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Christopher Haster 458fe16f38 Extended emubd to test metastability, added ckprog/ckread tests 
Metastability is a rather nasty error condition where successive reads
to a memory location may return different values, either due to bus
issues or a failed prog. It's a tricky error condition to detect, and
one that ckreads was, in theory, supposed to help with.

To help test metastability (and other single-bit errors), emubd gained
several new features:

- LFS_EMUBD_BADBLOCK_PROGFLIP    - Prog flips a bit
- LFS_EMUBD_BADBLOCK_READFLIP    - Read flips a bit sometimes
- LFS_EMUBD_POWERLOSS_METASTABLE - Reads may flip a bit

These only affect a single bit in a given block, but by randomizing
which bit during every erase (and exhaustive bit testing in test_ck) we
should still see some fairly interesting bit-error patterns over time.

It's a bit difficult to test with more than a single bit error because
you can quickly find checksum/parity collisions when fuzz testing. But
there may be other interesting error patterns to look at in the future?

Also the erase_cycles implementation got a bit of a rework since it was
lopsided previously (progs/reads would always error before erases). And
since I was messing with emubd's internals I added lfs_emubd_markbad/
markgood and a few other convenience functions that seem useful:

- lfs_emubd_seed - Manually set the prng, needed in test_ck actually
- lfs_emubd_markbad - Mark block as bad, same as wear=-1
- lfs_emubd_markgood - Mark block as good, same as wear=0
- lfs_emubd_badbit - Get which big failed
- lfs_emubd_setbadbit - Set which bit will fail
- lfs_emubd_randomizebadbit - Randomize bad bit on erase
- lfs_emubd_markbadbit - Mark bit as bad, same as setbadbit+markbad

---

The intention of this new metastability emulation was to extend test_ck
to test ckreads/ckprogs. This went... interestingly.

The good news, the new emulation and tests worked quite well. They were
able to quite quickly show that ckreads is fundamentally not able to
detect all single-bit errors in our current design.

The problem boils down to the fact that the location of our parity bits
depends on the tag's leb128-encoded size. If a bit flip changes this
size field, we end up with a new parity bit, which 50/50 may or may not
detect the error.

For example, one bit flip:

  40 0c 00 12 80 0d ff ff
  '----.----' ^--------------------.
       '- altble 0xc w0 -18 parity=1

  40 0c 80 12 80 0d ff ff
  '-------.-------' ^----------------------.
          '- altble 0xc w2304 -1664 parity=1

This doesn't make ckreads _completely_ useless, just mostly useless. We
can still use it to check parity bits, but without a systematic proof.

But there's enough problems with ckreads: performance, RAM, code, etc,
that I think it may just be an interesting proof-of-concept and not
something users should actually use. Checking reads in the bd-layer
solves all of these problems...

---

At the very least ckprogs gets better testing, thanks to new tests in
test_ck and the addition of LFS_EMUBD_BADBLOCK_PROGFLIP in
test_badblocks.

The extra testing also found a ckprog/ckread hole in that we don't
ckprog/ckread during lfsr_format! I fixed this by making lfsr_format
always use ckprogs/ckreads if available, but maybe lfsr_format should
take its own set of flags?

Funnily enough this had no impact on code size since it probably just
changed the constant in a constant pool:

          code           stack
  before: 37872           3048
  after:  37872 (+0.0%)   3048 (+0.0%)
2024-08-16 01:03:57 -05:00

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/*
* Emulating block device, wraps filebd and rambd while providing a bunch
* of hooks for testing littlefs in various conditions.
*
* Copyright (c) 2022, The littlefs authors.
* Copyright (c) 2017, Arm Limited. All rights reserved.
* SPDX-License-Identifier: BSD-3-Clause
*/
#ifndef _POSIX_C_SOURCE
#define _POSIX_C_SOURCE 199309L
#endif
#include "bd/lfs_emubd.h"
#include <stdlib.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>
#include <time.h>
#ifdef _WIN32
#include <windows.h>
#endif
// access to lazily-allocated/copy-on-write blocks
//
// Note we can only modify a block if we have exclusive access to it (rc == 1)
//
static lfs_emubd_block_t *lfs_emubd_incblock(lfs_emubd_block_t *block) {
if (block) {
block->rc += 1;
}
return block;
}
static void lfs_emubd_decblock(lfs_emubd_block_t *block) {
if (block) {
block->rc -= 1;
if (block->rc == 0) {
free(block);
}
}
}
static lfs_emubd_block_t *lfs_emubd_mutblock(
const struct lfs_config *cfg,
lfs_emubd_block_t *block) {
if (block && block->rc == 1) {
// rc == 1? can modify
return block;
} else if (block) {
// rc > 1? need to create a copy
lfs_emubd_block_t *block_ = malloc(
sizeof(lfs_emubd_block_t) + cfg->block_size);
if (!block_) {
return NULL;
}
memcpy(block_, block,
sizeof(lfs_emubd_block_t) + cfg->block_size);
block_->rc = 1;
lfs_emubd_decblock(block);
return block_;
} else {
// no block? need to allocate
lfs_emubd_block_t *block_ = malloc(
sizeof(lfs_emubd_block_t) + cfg->block_size);
if (!block_) {
return NULL;
}
block_->rc = 1;
block_->wear = 0;
block_->metastable = false;
block_->bad_bit = 0;
// zero for consistency
lfs_emubd_t *bd = cfg->context;
memset(block_->data,
(bd->cfg->erase_value != -1) ? bd->cfg->erase_value : 0,
cfg->block_size);
return block_;
}
}
// prng used for some emulation things
static uint32_t lfs_emubd_prng(uint32_t *state) {
// A simple xorshift32 generator, easily reproducible. Keep in mind
// determinism is much more important than actual randomness here.
uint32_t x = *state;
// must be non-zero, use uintmax here so that seed=0 is different
// from seed=1 and seed=range(0,n) makes a bit more sense
if (x == 0) {
x = -1;
}
x ^= x << 13;
x ^= x >> 17;
x ^= x << 5;
*state = x;
return x;
}
// emubd create/destroy
int lfs_emubd_createcfg(const struct lfs_config *cfg, const char *path,
const struct lfs_emubd_config *bdcfg) {
LFS_EMUBD_TRACE("lfs_emubd_createcfg(%p {.context=%p, "
".read=%p, .prog=%p, .erase=%p, .sync=%p, "
".read_size=%"PRIu32", .prog_size=%"PRIu32", "
".block_size=%"PRIu32", .block_count=%"PRIu32"}, "
"\"%s\", "
"%p {.erase_value=%"PRId32", .erase_cycles=%"PRIu32", "
".badblock_behavior=%"PRIu8", .power_cycles=%"PRIu32", "
".powerloss_behavior=%"PRIu8", .powerloss_cb=%p, "
".powerloss_data=%p, seed=%"PRIu32"})",
(void*)cfg, cfg->context,
(void*)(uintptr_t)cfg->read, (void*)(uintptr_t)cfg->prog,
(void*)(uintptr_t)cfg->erase, (void*)(uintptr_t)cfg->sync,
cfg->read_size, cfg->prog_size, cfg->block_size, cfg->block_count,
path, (void*)bdcfg, bdcfg->erase_value, bdcfg->erase_cycles,
bdcfg->badblock_behavior, bdcfg->power_cycles,
bdcfg->powerloss_behavior, (void*)(uintptr_t)bdcfg->powerloss_cb,
bdcfg->powerloss_data, bdcfg->seed);
lfs_emubd_t *bd = cfg->context;
bd->cfg = bdcfg;
// setup testing things
bd->blocks = NULL;
bd->readed = 0;
bd->proged = 0;
bd->erased = 0;
bd->prng = bd->cfg->seed;
bd->power_cycles = bd->cfg->power_cycles;
bd->ooo_before = NULL;
bd->ooo_after = NULL;
bd->disk = NULL;
// allocate our block array, all blocks start as uninitialized
bd->blocks = malloc(
cfg->block_count * sizeof(lfs_emubd_block_t*));
int err;
if (!bd->blocks) {
err = LFS_ERR_NOMEM;
goto failed;
}
memset(bd->blocks, 0,
cfg->block_count * sizeof(lfs_emubd_block_t*));
// allocate extra block arrays to hold our ooo snapshots
if (bd->cfg->powerloss_behavior == LFS_EMUBD_POWERLOSS_OOO) {
bd->ooo_before = malloc(
cfg->block_count * sizeof(lfs_emubd_block_t*));
if (!bd->ooo_before) {
err = LFS_ERR_NOMEM;
goto failed;
}
memset(bd->ooo_before, 0,
cfg->block_count * sizeof(lfs_emubd_block_t*));
bd->ooo_after = malloc(
cfg->block_count * sizeof(lfs_emubd_block_t*));
if (!bd->ooo_after) {
err = LFS_ERR_NOMEM;
goto failed;
}
memset(bd->ooo_after, 0,
cfg->block_count * sizeof(lfs_emubd_block_t*));
}
if (bd->cfg->disk_path) {
bd->disk = malloc(sizeof(lfs_emubd_disk_t));
if (!bd->disk) {
err = LFS_ERR_NOMEM;
goto failed;
}
bd->disk->rc = 1;
bd->disk->fd = -1;
bd->disk->scratch = NULL;
#ifdef _WIN32
bd->disk->fd = open(bd->cfg->disk_path,
O_RDWR | O_CREAT | O_BINARY, 0666);
#else
bd->disk->fd = open(bd->cfg->disk_path,
O_RDWR | O_CREAT, 0666);
#endif
if (bd->disk->fd < 0) {
err = -errno;
goto failed;
}
bd->disk->scratch = malloc(cfg->block_size);
if (!bd->disk->scratch) {
err = LFS_ERR_NOMEM;
goto failed;
}
memset(bd->disk->scratch,
(bd->cfg->erase_value != -1) ? bd->cfg->erase_value : 0,
cfg->block_size);
// go ahead and erase all of the disk, otherwise the file will not
// match our internal representation
for (size_t i = 0; i < cfg->block_count; i++) {
ssize_t res = write(bd->disk->fd,
bd->disk->scratch,
cfg->block_size);
if (res < 0) {
err = -errno;
goto failed;
}
}
}
LFS_EMUBD_TRACE("lfs_emubd_createcfg -> %d", 0);
return 0;
failed:;
LFS_EMUBD_TRACE("lfs_emubd_createcfg -> %d", err);
// clean up memory
free(bd->blocks);
if (bd->cfg->powerloss_behavior == LFS_EMUBD_POWERLOSS_OOO) {
free(bd->ooo_before);
free(bd->ooo_after);
}
if (bd->disk) {
if (bd->disk->fd != -1) {
close(bd->disk->fd);
}
free(bd->disk->scratch);
free(bd->disk);
}
return err;
}
int lfs_emubd_create(const struct lfs_config *cfg, const char *path) {
LFS_EMUBD_TRACE("lfs_emubd_create(%p {.context=%p, "
".read=%p, .prog=%p, .erase=%p, .sync=%p, "
".read_size=%"PRIu32", .prog_size=%"PRIu32", "
".block_size=%"PRIu32", .block_count=%"PRIu32"}, "
"\"%s\")",
(void*)cfg, cfg->context,
(void*)(uintptr_t)cfg->read, (void*)(uintptr_t)cfg->prog,
(void*)(uintptr_t)cfg->erase, (void*)(uintptr_t)cfg->sync,
cfg->read_size, cfg->prog_size, cfg->block_size, cfg->block_count,
path);
static const struct lfs_emubd_config defaults = {.erase_value=-1};
int err = lfs_emubd_createcfg(cfg, path, &defaults);
LFS_EMUBD_TRACE("lfs_emubd_create -> %d", err);
return err;
}
int lfs_emubd_destroy(const struct lfs_config *cfg) {
LFS_EMUBD_TRACE("lfs_emubd_destroy(%p)", (void*)cfg);
lfs_emubd_t *bd = cfg->context;
// decrement reference counts
for (lfs_block_t i = 0; i < cfg->block_count; i++) {
lfs_emubd_decblock(bd->blocks[i]);
}
free(bd->blocks);
if (bd->cfg->powerloss_behavior == LFS_EMUBD_POWERLOSS_OOO) {
for (lfs_block_t i = 0; i < cfg->block_count; i++) {
lfs_emubd_decblock(bd->ooo_before[i]);
}
free(bd->ooo_before);
for (lfs_block_t i = 0; i < cfg->block_count; i++) {
lfs_emubd_decblock(bd->ooo_after[i]);
}
free(bd->ooo_after);
}
// clean up other resources
if (bd->disk) {
bd->disk->rc -= 1;
if (bd->disk->rc == 0) {
close(bd->disk->fd);
free(bd->disk->scratch);
free(bd->disk);
}
}
LFS_EMUBD_TRACE("lfs_emubd_destroy -> %d", 0);
return 0;
}
// block device API
int lfs_emubd_read(const struct lfs_config *cfg, lfs_block_t block,
lfs_off_t off, void *buffer, lfs_size_t size) {
LFS_EMUBD_TRACE("lfs_emubd_read(%p, "
"0x%"PRIx32", %"PRIu32", %p, %"PRIu32")",
(void*)cfg, block, off, buffer, size);
lfs_emubd_t *bd = cfg->context;
// check if read is valid
LFS_ASSERT(block < cfg->block_count);
LFS_ASSERT(off % cfg->read_size == 0);
LFS_ASSERT(size % cfg->read_size == 0);
LFS_ASSERT(off+size <= cfg->block_size);
// get the block
const lfs_emubd_block_t *b = bd->blocks[block];
if (b) {
// block bad?
if (b->wear > bd->cfg->erase_cycles) {
// erroring reads? error
if (bd->cfg->badblock_behavior
== LFS_EMUBD_BADBLOCK_READERROR) {
LFS_EMUBD_TRACE("lfs_emubd_read -> %d", LFS_ERR_CORRUPT);
return LFS_ERR_CORRUPT;
}
}
// read data
memcpy(buffer, &b->data[off], size);
// metastable? randomly decide if our bad bit flips
if (b->metastable) {
lfs_size_t bit = b->bad_bit & 0x7fffffff;
if (bit/8 >= off
&& bit/8 < off+size
&& (lfs_emubd_prng(&bd->prng) & 1)) {
((uint8_t*)buffer)[(bit/8) - off] ^= 1 << (bit%8);
}
}
// no block yet
} else {
// zero for consistency
memset(buffer,
(bd->cfg->erase_value != -1) ? bd->cfg->erase_value : 0,
size);
}
// track reads
bd->readed += size;
if (bd->cfg->read_sleep) {
int err = nanosleep(&(struct timespec){
.tv_sec=bd->cfg->read_sleep/1000000000,
.tv_nsec=bd->cfg->read_sleep%1000000000},
NULL);
if (err) {
err = -errno;
LFS_EMUBD_TRACE("lfs_emubd_read -> %d", err);
return err;
}
}
LFS_EMUBD_TRACE("lfs_emubd_read -> %d", 0);
return 0;
}
int lfs_emubd_prog(const struct lfs_config *cfg, lfs_block_t block,
lfs_off_t off, const void *buffer, lfs_size_t size) {
LFS_EMUBD_TRACE("lfs_emubd_prog(%p, "
"0x%"PRIx32", %"PRIu32", %p, %"PRIu32")",
(void*)cfg, block, off, buffer, size);
lfs_emubd_t *bd = cfg->context;
// check if write is valid
LFS_ASSERT(block < cfg->block_count);
LFS_ASSERT(off % cfg->prog_size == 0);
LFS_ASSERT(size % cfg->prog_size == 0);
LFS_ASSERT(off+size <= cfg->block_size);
// were we erased properly?
LFS_ASSERT(bd->blocks[block]);
if (bd->cfg->erase_value != -1
&& bd->blocks[block]->wear <= bd->cfg->erase_cycles) {
for (lfs_off_t i = 0; i < size; i++) {
LFS_ASSERT(bd->blocks[block]->data[off+i] == bd->cfg->erase_value);
}
}
// losing power?
if (bd->power_cycles > 0) {
bd->power_cycles -= 1;
if (bd->power_cycles == 0) {
// emulating some bits? choose a random bit to flip
if (bd->cfg->powerloss_behavior
== LFS_EMUBD_POWERLOSS_SOMEBITS) {
// mutate the block
lfs_emubd_block_t *b = lfs_emubd_mutblock(cfg,
bd->blocks[block]);
if (!b) {
LFS_EMUBD_TRACE("lfs_emubd_prog -> %d", LFS_ERR_NOMEM);
return LFS_ERR_NOMEM;
}
bd->blocks[block] = b;
// flip bit
lfs_size_t bit = lfs_emubd_prng(&bd->prng)
% (cfg->prog_size*8);
b->data[off + (bit/8)] ^= 1 << (bit%8);
// mirror to disk file?
if (bd->disk) {
off_t res1 = lseek(bd->disk->fd,
(off_t)block*cfg->block_size + (off_t)off,
SEEK_SET);
if (res1 < 0) {
int err = -errno;
LFS_EMUBD_TRACE("lfs_emubd_prog -> %d", err);
return err;
}
ssize_t res2 = write(bd->disk->fd, &b->data[off], size);
if (res2 < 0) {
int err = -errno;
LFS_EMUBD_TRACE("lfs_emubd_prog -> %d", err);
return err;
}
}
// emulating most bits? prog data and choose a random bit
// to flip
} else if (bd->cfg->powerloss_behavior
== LFS_EMUBD_POWERLOSS_MOSTBITS) {
// mutate the block
lfs_emubd_block_t *b = lfs_emubd_mutblock(cfg,
bd->blocks[block]);
if (!b) {
LFS_EMUBD_TRACE("lfs_emubd_prog -> %d", LFS_ERR_NOMEM);
return LFS_ERR_NOMEM;
}
bd->blocks[block] = b;
// prog data
memcpy(&b->data[off], buffer, size);
// flip bit
lfs_size_t bit = lfs_emubd_prng(&bd->prng)
% (cfg->prog_size*8);
b->data[off + (bit/8)] ^= 1 << (bit%8);
// mirror to disk file?
if (bd->disk) {
off_t res1 = lseek(bd->disk->fd,
(off_t)block*cfg->block_size + (off_t)off,
SEEK_SET);
if (res1 < 0) {
int err = -errno;
LFS_EMUBD_TRACE("lfs_emubd_prog -> %d", err);
return err;
}
ssize_t res2 = write(bd->disk->fd, &b->data[off], size);
if (res2 < 0) {
int err = -errno;
LFS_EMUBD_TRACE("lfs_emubd_prog -> %d", err);
return err;
}
}
// emulating out-of-order writes? revert everything unsynced
// except for our current block
} else if (bd->cfg->powerloss_behavior
== LFS_EMUBD_POWERLOSS_OOO) {
for (lfs_block_t i = 0; i < cfg->block_count; i++) {
lfs_emubd_decblock(bd->ooo_after[i]);
bd->ooo_after[i] = lfs_emubd_incblock(bd->blocks[i]);
if (i != block && bd->blocks[i] != bd->ooo_before[i]) {
lfs_emubd_decblock(bd->blocks[i]);
bd->blocks[i] = lfs_emubd_incblock(bd->ooo_before[i]);
// mirror to disk file?
if (bd->disk) {
off_t res1 = lseek(bd->disk->fd,
(off_t)i*cfg->block_size,
SEEK_SET);
if (res1 < 0) {
int err = -errno;
LFS_EMUBD_TRACE("lfs_emubd_prog -> %d", err);
return err;
}
ssize_t res2 = write(bd->disk->fd,
(bd->blocks[i])
? bd->blocks[i]->data
: bd->disk->scratch,
cfg->block_size);
if (res2 < 0) {
int err = -errno;
LFS_EMUBD_TRACE("lfs_emubd_prog -> %d", err);
return err;
}
}
}
}
// emulating metastability? prog data, choose a random bad bit,
// and mark as metastable
} else if (bd->cfg->powerloss_behavior
== LFS_EMUBD_POWERLOSS_METASTABLE) {
// mutate the block
lfs_emubd_block_t *b = lfs_emubd_mutblock(cfg,
bd->blocks[block]);
if (!b) {
LFS_EMUBD_TRACE("lfs_emubd_prog -> %d", LFS_ERR_NOMEM);
return LFS_ERR_NOMEM;
}
bd->blocks[block] = b;
// prog data
memcpy(&b->data[off], buffer, size);
// choose a new bad bit unless overridden
if (!(0x80000000 & b->bad_bit)) {
b->bad_bit = lfs_emubd_prng(&bd->prng)
% (cfg->block_size*8);
}
// mark as metastable
b->metastable = true;
// mirror to disk file?
if (bd->disk) {
off_t res1 = lseek(bd->disk->fd,
(off_t)block*cfg->block_size + (off_t)off,
SEEK_SET);
if (res1 < 0) {
int err = -errno;
LFS_EMUBD_TRACE("lfs_emubd_prog -> %d", err);
return err;
}
ssize_t res2 = write(bd->disk->fd, &b->data[off], size);
if (res2 < 0) {
int err = -errno;
LFS_EMUBD_TRACE("lfs_emubd_prog -> %d", err);
return err;
}
}
}
// powerloss!
bd->cfg->powerloss_cb(bd->cfg->powerloss_data);
// oh, continuing? undo out-of-order write emulation
if (bd->cfg->powerloss_behavior == LFS_EMUBD_POWERLOSS_OOO) {
for (lfs_block_t i = 0; i < cfg->block_count; i++) {
if (bd->blocks[i] != bd->ooo_after[i]) {
lfs_emubd_decblock(bd->blocks[i]);
bd->blocks[i] = lfs_emubd_incblock(bd->ooo_after[i]);
// mirror to disk file?
if (bd->disk) {
off_t res1 = lseek(bd->disk->fd,
(off_t)i*cfg->block_size,
SEEK_SET);
if (res1 < 0) {
int err = -errno;
LFS_EMUBD_TRACE("lfs_emubd_prog -> %d", err);
return err;
}
ssize_t res2 = write(bd->disk->fd,
(bd->blocks[i])
? bd->blocks[i]->data
: bd->disk->scratch,
cfg->block_size);
if (res2 < 0) {
int err = -errno;
LFS_EMUBD_TRACE("lfs_emubd_prog -> %d", err);
return err;
}
}
}
}
}
}
}
// mutate the block
lfs_emubd_block_t *b = lfs_emubd_mutblock(cfg, bd->blocks[block]);
if (!b) {
LFS_EMUBD_TRACE("lfs_emubd_prog -> %d", LFS_ERR_NOMEM);
return LFS_ERR_NOMEM;
}
bd->blocks[block] = b;
// block bad?
if (b->wear > bd->cfg->erase_cycles) {
// erroring progs? error
if (bd->cfg->badblock_behavior
== LFS_EMUBD_BADBLOCK_PROGERROR) {
LFS_EMUBD_TRACE("lfs_emubd_prog -> %d", LFS_ERR_CORRUPT);
return LFS_ERR_CORRUPT;
// noop progs? skip
} else if (bd->cfg->badblock_behavior
== LFS_EMUBD_BADBLOCK_PROGNOOP
|| bd->cfg->badblock_behavior
== LFS_EMUBD_BADBLOCK_ERASENOOP) {
goto progged;
// progs flipping bits? flip our bad bit, exactly which bit
// is chosen during erase
} else if (bd->cfg->badblock_behavior
== LFS_EMUBD_BADBLOCK_PROGFLIP) {
lfs_size_t bit = b->bad_bit & 0x7fffffff;
if (bit/8 >= off && bit/8 < off+size) {
memcpy(&b->data[off], buffer, size);
b->data[bit/8] ^= 1 << (bit%8);
goto progged;
}
// reads flipping bits? prog as normal but mark as metastable
} else if (bd->cfg->badblock_behavior
== LFS_EMUBD_BADBLOCK_READFLIP) {
memcpy(&b->data[off], buffer, size);
b->metastable = true;
goto progged;
}
}
// prog data
memcpy(&b->data[off], buffer, size);
// clear any metastability
b->metastable = false;
progged:;
// mirror to disk file?
if (bd->disk) {
off_t res1 = lseek(bd->disk->fd,
(off_t)block*cfg->block_size + (off_t)off,
SEEK_SET);
if (res1 < 0) {
int err = -errno;
LFS_EMUBD_TRACE("lfs_emubd_prog -> %d", err);
return err;
}
ssize_t res2 = write(bd->disk->fd, &b->data[off], size);
if (res2 < 0) {
int err = -errno;
LFS_EMUBD_TRACE("lfs_emubd_prog -> %d", err);
return err;
}
}
// track progs
bd->proged += size;
if (bd->cfg->prog_sleep) {
int err = nanosleep(&(struct timespec){
.tv_sec=bd->cfg->prog_sleep/1000000000,
.tv_nsec=bd->cfg->prog_sleep%1000000000},
NULL);
if (err) {
err = -errno;
LFS_EMUBD_TRACE("lfs_emubd_prog -> %d", err);
return err;
}
}
LFS_EMUBD_TRACE("lfs_emubd_prog -> %d", 0);
return 0;
}
int lfs_emubd_erase(const struct lfs_config *cfg, lfs_block_t block) {
LFS_EMUBD_TRACE("lfs_emubd_erase(%p, 0x%"PRIx32" (%"PRIu32"))",
(void*)cfg, block, cfg->block_size);
lfs_emubd_t *bd = cfg->context;
// check if erase is valid
LFS_ASSERT(block < cfg->block_count);
// losing power?
if (bd->power_cycles > 0) {
bd->power_cycles -= 1;
if (bd->power_cycles == 0) {
// emulating some bits? choose a random bit to flip
if (bd->cfg->powerloss_behavior
== LFS_EMUBD_POWERLOSS_SOMEBITS) {
// mutate the block
lfs_emubd_block_t *b = lfs_emubd_mutblock(cfg,
bd->blocks[block]);
if (!b) {
LFS_EMUBD_TRACE("lfs_emubd_erase -> %d", LFS_ERR_NOMEM);
return LFS_ERR_NOMEM;
}
bd->blocks[block] = b;
// flip bit
lfs_size_t bit = lfs_emubd_prng(&bd->prng)
% (cfg->block_size*8);
b->data[(bit/8)] ^= 1 << (bit%8);
// mirror to disk file?
if (bd->disk) {
off_t res1 = lseek(bd->disk->fd,
(off_t)block*cfg->block_size,
SEEK_SET);
if (res1 < 0) {
int err = -errno;
LFS_EMUBD_TRACE("lfs_emubd_erase -> %d", err);
return err;
}
ssize_t res2 = write(bd->disk->fd,
b->data, cfg->block_size);
if (res2 < 0) {
int err = -errno;
LFS_EMUBD_TRACE("lfs_emubd_erase -> %d", err);
return err;
}
}
// emulating most bits? erase data and choose a random bit
// to flip
} else if (bd->cfg->powerloss_behavior
== LFS_EMUBD_POWERLOSS_MOSTBITS) {
// mutate the block
lfs_emubd_block_t *b = lfs_emubd_mutblock(cfg,
bd->blocks[block]);
if (!b) {
LFS_EMUBD_TRACE("lfs_emubd_erase -> %d", LFS_ERR_NOMEM);
return LFS_ERR_NOMEM;
}
bd->blocks[block] = b;
// emulate an erase value?
if (bd->cfg->erase_value != -1) {
memset(b->data, bd->cfg->erase_value, cfg->block_size);
}
// flip bit
lfs_size_t bit = lfs_emubd_prng(&bd->prng)
% (cfg->block_size*8);
b->data[(bit/8)] ^= 1 << (bit%8);
// mirror to disk file?
if (bd->disk) {
off_t res1 = lseek(bd->disk->fd,
(off_t)block*cfg->block_size,
SEEK_SET);
if (res1 < 0) {
int err = -errno;
LFS_EMUBD_TRACE("lfs_emubd_erase -> %d", err);
return err;
}
ssize_t res2 = write(bd->disk->fd,
b->data, cfg->block_size);
if (res2 < 0) {
int err = -errno;
LFS_EMUBD_TRACE("lfs_emubd_erase -> %d", err);
return err;
}
}
// emulating out-of-order writes? revert everything unsynced
// except for our current block
} else if (bd->cfg->powerloss_behavior
== LFS_EMUBD_POWERLOSS_OOO) {
for (lfs_block_t i = 0; i < cfg->block_count; i++) {
if (i != block && bd->blocks[i] != bd->ooo_before[i]) {
lfs_emubd_decblock(bd->blocks[i]);
bd->blocks[i] = lfs_emubd_incblock(bd->ooo_before[i]);
// mirror to disk file?
if (bd->disk) {
off_t res1 = lseek(bd->disk->fd,
(off_t)i*cfg->block_size,
SEEK_SET);
if (res1 < 0) {
int err = -errno;
LFS_EMUBD_TRACE("lfs_emubd_erase -> %d", err);
return err;
}
ssize_t res2 = write(bd->disk->fd,
(bd->blocks[i])
? bd->blocks[i]->data
: bd->disk->scratch,
cfg->block_size);
if (res2 < 0) {
int err = -errno;
LFS_EMUBD_TRACE("lfs_emubd_erase -> %d", err);
return err;
}
}
}
}
// emulating metastability? erase data, choose a random bad bit,
// and mark as metastable
} else if (bd->cfg->powerloss_behavior
== LFS_EMUBD_POWERLOSS_METASTABLE) {
// mutate the block
lfs_emubd_block_t *b = lfs_emubd_mutblock(cfg,
bd->blocks[block]);
if (!b) {
LFS_EMUBD_TRACE("lfs_emubd_erase -> %d", LFS_ERR_NOMEM);
return LFS_ERR_NOMEM;
}
bd->blocks[block] = b;
// emulate an erase value?
if (bd->cfg->erase_value != -1) {
memset(b->data, bd->cfg->erase_value, cfg->block_size);
}
// choose a new bad bit unless overridden
if (!(0x80000000 & b->bad_bit)) {
b->bad_bit = lfs_emubd_prng(&bd->prng)
% (cfg->block_size*8);
}
// mark as metastable
b->metastable = true;
// mirror to disk file?
if (bd->disk) {
off_t res1 = lseek(bd->disk->fd,
(off_t)block*cfg->block_size,
SEEK_SET);
if (res1 < 0) {
int err = -errno;
LFS_EMUBD_TRACE("lfs_emubd_erase -> %d", err);
return err;
}
ssize_t res2 = write(bd->disk->fd,
b->data, cfg->block_size);
if (res2 < 0) {
int err = -errno;
LFS_EMUBD_TRACE("lfs_emubd_erase -> %d", err);
return err;
}
}
}
// powerloss!
bd->cfg->powerloss_cb(bd->cfg->powerloss_data);
// oh, continuing? undo out-of-order write emulation
if (bd->cfg->powerloss_behavior == LFS_EMUBD_POWERLOSS_OOO) {
for (lfs_block_t i = 0; i < cfg->block_count; i++) {
if (bd->blocks[i] != bd->ooo_after[i]) {
lfs_emubd_decblock(bd->blocks[i]);
bd->blocks[i] = lfs_emubd_incblock(bd->ooo_after[i]);
// mirror to disk file?
if (bd->disk) {
off_t res1 = lseek(bd->disk->fd,
(off_t)i*cfg->block_size,
SEEK_SET);
if (res1 < 0) {
int err = -errno;
LFS_EMUBD_TRACE("lfs_emubd_erase -> %d", err);
return err;
}
ssize_t res2 = write(bd->disk->fd,
(bd->blocks[i])
? bd->blocks[i]->data
: bd->disk->scratch,
cfg->block_size);
if (res2 < 0) {
int err = -errno;
LFS_EMUBD_TRACE("lfs_emubd_erase -> %d", err);
return err;
}
}
}
}
}
}
}
// mutate the block
lfs_emubd_block_t *b = lfs_emubd_mutblock(cfg, bd->blocks[block]);
if (!b) {
LFS_EMUBD_TRACE("lfs_emubd_erase -> %d", LFS_ERR_NOMEM);
return LFS_ERR_NOMEM;
}
bd->blocks[block] = b;
// keep track of wear
if (bd->cfg->erase_cycles && b->wear <= bd->cfg->erase_cycles) {
b->wear += 1;
}
// block bad?
if (b->wear > bd->cfg->erase_cycles) {
// erroring erases? error
if (bd->cfg->badblock_behavior
== LFS_EMUBD_BADBLOCK_ERASEERROR) {
LFS_EMUBD_TRACE("lfs_emubd_erase -> %d", LFS_ERR_CORRUPT);
return LFS_ERR_CORRUPT;
// noop erases? skip
} else if (bd->cfg->badblock_behavior
== LFS_EMUBD_BADBLOCK_ERASENOOP) {
goto erased;
// flipping bits? if we're not manually overridden, choose a
// new bad bit on erase, this makes it more likely to
// eventually cause problems
} else if (bd->cfg->badblock_behavior
== LFS_EMUBD_BADBLOCK_PROGFLIP
|| bd->cfg->badblock_behavior
== LFS_EMUBD_BADBLOCK_READFLIP) {
if (!(0x80000000 & b->bad_bit)) {
b->bad_bit = lfs_emubd_prng(&bd->prng)
% (cfg->block_size*8);
}
}
}
// emulate an erase value?
if (bd->cfg->erase_value != -1) {
memset(b->data, bd->cfg->erase_value, cfg->block_size);
// mirror to disk file?
if (bd->disk) {
off_t res1 = lseek(bd->disk->fd,
(off_t)block*cfg->block_size,
SEEK_SET);
if (res1 < 0) {
int err = -errno;
LFS_EMUBD_TRACE("lfs_emubd_erase -> %d", err);
return err;
}
ssize_t res2 = write(bd->disk->fd, b->data, cfg->block_size);
if (res2 < 0) {
int err = -errno;
LFS_EMUBD_TRACE("lfs_emubd_erase -> %d", err);
return err;
}
}
}
// clear any metastability
b->metastable = false;
erased:;
// track erases
bd->erased += cfg->block_size;
if (bd->cfg->erase_sleep) {
int err = nanosleep(&(struct timespec){
.tv_sec=bd->cfg->erase_sleep/1000000000,
.tv_nsec=bd->cfg->erase_sleep%1000000000},
NULL);
if (err) {
err = -errno;
LFS_EMUBD_TRACE("lfs_emubd_erase -> %d", err);
return err;
}
}
LFS_EMUBD_TRACE("lfs_emubd_erase -> %d", 0);
return 0;
}
int lfs_emubd_sync(const struct lfs_config *cfg) {
LFS_EMUBD_TRACE("lfs_emubd_sync(%p)", (void*)cfg);
lfs_emubd_t *bd = cfg->context;
// emulate out-of-order writes? save a snapshot on sync
if (bd->cfg->powerloss_behavior == LFS_EMUBD_POWERLOSS_OOO) {
for (size_t i = 0; i < cfg->block_count; i++) {
lfs_emubd_decblock(bd->ooo_before[i]);
bd->ooo_before[i] = lfs_emubd_incblock(bd->blocks[i]);
}
}
LFS_EMUBD_TRACE("lfs_emubd_sync -> %d", 0);
return 0;
}
/// Additional extended API for driving test features ///
int lfs_emubd_seed(const struct lfs_config *cfg, uint32_t seed) {
LFS_EMUBD_TRACE("lfs_emubd_seed(%p, 0x%08"PRIx32")",
(void*)cfg, seed);
lfs_emubd_t *bd = cfg->context;
bd->prng = seed;
LFS_EMUBD_TRACE("lfs_emubd_seed -> %d", 0);
return 0;
}
static int lfs_emubd_rawcksum(const struct lfs_config *cfg,
lfs_block_t block, uint32_t *cksum) {
lfs_emubd_t *bd = cfg->context;
// check if block is valid
LFS_ASSERT(block < cfg->block_count);
// checksum the block
uint32_t cksum_ = 0;
const lfs_emubd_block_t *b = bd->blocks[block];
if (b) {
cksum_ = lfs_crc32c(cksum_, b->data, cfg->block_size);
} else {
uint8_t erase_value = (bd->cfg->erase_value != -1)
? bd->cfg->erase_value
: 0;
for (lfs_size_t i = 0; i < cfg->block_size; i++) {
cksum_ = lfs_crc32c(cksum_, &erase_value, 1);
}
}
*cksum = cksum_;
return 0;
}
int lfs_emubd_cksum(const struct lfs_config *cfg,
lfs_block_t block, uint32_t *cksum) {
LFS_EMUBD_TRACE("lfs_emubd_cksum(%p, %"PRIu32", %p)",
(void*)cfg, block, cksum);
int err = lfs_emubd_rawcksum(cfg, block, cksum);
LFS_EMUBD_TRACE("lfs_emubd_cksum -> %d", err);
return err;
}
int lfs_emubd_bdcrc(const struct lfs_config *cfg, uint32_t *cksum) {
LFS_EMUBD_TRACE("lfs_emubd_bdcksum(%p, %p)", (void*)cfg, cksum);
uint32_t cksum_ = 0;
for (lfs_block_t i = 0; i < cfg->block_count; i++) {
uint32_t i_cksum;
int err = lfs_emubd_rawcksum(cfg, i, &i_cksum);
if (err) {
LFS_EMUBD_TRACE("lfs_emubd_bdcksum -> %d", err);
return err;
}
cksum_ = lfs_crc32c(cksum_, &i_cksum, sizeof(uint32_t));
}
*cksum = cksum_;
LFS_EMUBD_TRACE("lfs_emubd_bdcksum -> %d", 0);
return 0;
}
lfs_emubd_sio_t lfs_emubd_readed(const struct lfs_config *cfg) {
LFS_EMUBD_TRACE("lfs_emubd_readed(%p)", (void*)cfg);
lfs_emubd_t *bd = cfg->context;
LFS_EMUBD_TRACE("lfs_emubd_readed -> %"PRIu64, bd->readed);
return bd->readed;
}
lfs_emubd_sio_t lfs_emubd_proged(const struct lfs_config *cfg) {
LFS_EMUBD_TRACE("lfs_emubd_proged(%p)", (void*)cfg);
lfs_emubd_t *bd = cfg->context;
LFS_EMUBD_TRACE("lfs_emubd_proged -> %"PRIu64, bd->proged);
return bd->proged;
}
lfs_emubd_sio_t lfs_emubd_erased(const struct lfs_config *cfg) {
LFS_EMUBD_TRACE("lfs_emubd_erased(%p)", (void*)cfg);
lfs_emubd_t *bd = cfg->context;
LFS_EMUBD_TRACE("lfs_emubd_erased -> %"PRIu64, bd->erased);
return bd->erased;
}
int lfs_emubd_setreaded(const struct lfs_config *cfg, lfs_emubd_io_t readed) {
LFS_EMUBD_TRACE("lfs_emubd_setreaded(%p, %"PRIu64")", (void*)cfg, readed);
lfs_emubd_t *bd = cfg->context;
bd->readed = readed;
LFS_EMUBD_TRACE("lfs_emubd_setreaded -> %d", 0);
return 0;
}
int lfs_emubd_setproged(const struct lfs_config *cfg, lfs_emubd_io_t proged) {
LFS_EMUBD_TRACE("lfs_emubd_setproged(%p, %"PRIu64")", (void*)cfg, proged);
lfs_emubd_t *bd = cfg->context;
bd->proged = proged;
LFS_EMUBD_TRACE("lfs_emubd_setproged -> %d", 0);
return 0;
}
int lfs_emubd_seterased(const struct lfs_config *cfg, lfs_emubd_io_t erased) {
LFS_EMUBD_TRACE("lfs_emubd_seterased(%p, %"PRIu64")", (void*)cfg, erased);
lfs_emubd_t *bd = cfg->context;
bd->erased = erased;
LFS_EMUBD_TRACE("lfs_emubd_seterased -> %d", 0);
return 0;
}
lfs_emubd_swear_t lfs_emubd_wear(const struct lfs_config *cfg,
lfs_block_t block) {
LFS_EMUBD_TRACE("lfs_emubd_wear(%p, %"PRIu32")", (void*)cfg, block);
lfs_emubd_t *bd = cfg->context;
// check if block is valid
LFS_ASSERT(block < cfg->block_count);
// get the wear
lfs_emubd_wear_t wear;
const lfs_emubd_block_t *b = bd->blocks[block];
if (b) {
wear = b->wear;
} else {
wear = 0;
}
LFS_EMUBD_TRACE("lfs_emubd_wear -> %"PRIi32, wear);
return wear;
}
int lfs_emubd_setwear(const struct lfs_config *cfg,
lfs_block_t block, lfs_emubd_wear_t wear) {
LFS_EMUBD_TRACE("lfs_emubd_setwear(%p, %"PRIu32", %"PRIi32")",
(void*)cfg, block, wear);
lfs_emubd_t *bd = cfg->context;
// check if block is valid
LFS_ASSERT(block < cfg->block_count);
// mutate the block
lfs_emubd_block_t *b = lfs_emubd_mutblock(cfg, bd->blocks[block]);
if (!b) {
LFS_EMUBD_TRACE("lfs_emubd_setwear -> %d", LFS_ERR_NOMEM);
return LFS_ERR_NOMEM;
}
bd->blocks[block] = b;
// set the wear
b->wear = wear;
LFS_EMUBD_TRACE("lfs_emubd_setwear -> %d", 0);
return 0;
}
int lfs_emubd_markbad(const struct lfs_config *cfg,
lfs_block_t block) {
LFS_EMUBD_TRACE("lfs_emubd_markbad(%p, %"PRIu32")",
(void*)cfg, block);
lfs_emubd_t *bd = cfg->context;
// check if block is valid
LFS_ASSERT(block < cfg->block_count);
// mutate the block
lfs_emubd_block_t *b = lfs_emubd_mutblock(cfg, bd->blocks[block]);
if (!b) {
LFS_EMUBD_TRACE("lfs_emubd_markbad -> %d", LFS_ERR_NOMEM);
return LFS_ERR_NOMEM;
}
bd->blocks[block] = b;
// set the wear
b->wear = -1;
LFS_EMUBD_TRACE("lfs_emubd_markbad -> %d", 0);
return 0;
}
int lfs_emubd_markgood(const struct lfs_config *cfg,
lfs_block_t block) {
LFS_EMUBD_TRACE("lfs_emubd_markgood(%p, %"PRIu32")",
(void*)cfg, block);
lfs_emubd_t *bd = cfg->context;
// check if block is valid
LFS_ASSERT(block < cfg->block_count);
// mutate the block
lfs_emubd_block_t *b = lfs_emubd_mutblock(cfg, bd->blocks[block]);
if (!b) {
LFS_EMUBD_TRACE("lfs_emubd_markgood -> %d", LFS_ERR_NOMEM);
return LFS_ERR_NOMEM;
}
bd->blocks[block] = b;
// set the wear
b->wear = 0;
LFS_EMUBD_TRACE("lfs_emubd_markgood -> %d", 0);
return 0;
}
lfs_ssize_t lfs_emubd_badbit(const struct lfs_config *cfg,
lfs_block_t block) {
LFS_EMUBD_TRACE("lfs_emubd_badbit(%p, %"PRIu32")", (void*)cfg, block);
lfs_emubd_t *bd = cfg->context;
// check if block is valid
LFS_ASSERT(block < cfg->block_count);
// get the bad bit
lfs_size_t bad_bit;
const lfs_emubd_block_t *b = bd->blocks[block];
if (b) {
bad_bit = 0x7fffffff & b->bad_bit;
} else {
bad_bit = 0;
}
LFS_EMUBD_TRACE("lfs_emubd_badbit -> %"PRIi32, bad_bit);
return bad_bit;
}
int lfs_emubd_setbadbit(const struct lfs_config *cfg,
lfs_block_t block, lfs_size_t bit) {
LFS_EMUBD_TRACE("lfs_emubd_setbadbit(%p, %"PRIu32", %"PRIu32")",
(void*)cfg, block, bit);
lfs_emubd_t *bd = cfg->context;
// check if block is valid
LFS_ASSERT(block < cfg->block_count);
// mutate the block
lfs_emubd_block_t *b = lfs_emubd_mutblock(cfg, bd->blocks[block]);
if (!b) {
LFS_EMUBD_TRACE("lfs_emubd_setbadbit -> %d", LFS_ERR_NOMEM);
return LFS_ERR_NOMEM;
}
bd->blocks[block] = b;
// set the bad bit and mark as fixed
b->bad_bit = 0x80000000 | bit;
LFS_EMUBD_TRACE("lfs_emubd_setbadbit -> %d", 0);
return 0;
}
int lfs_emubd_randomizebadbit(const struct lfs_config *cfg,
lfs_block_t block) {
LFS_EMUBD_TRACE("lfs_emubd_randomizebadbit(%p, %"PRIu32")",
(void*)cfg, block);
lfs_emubd_t *bd = cfg->context;
// check if block is valid
LFS_ASSERT(block < cfg->block_count);
// mutate the block
lfs_emubd_block_t *b = lfs_emubd_mutblock(cfg, bd->blocks[block]);
if (!b) {
LFS_EMUBD_TRACE("lfs_emubd_randomizebadbit -> %d", LFS_ERR_NOMEM);
return LFS_ERR_NOMEM;
}
bd->blocks[block] = b;
// mark the bad bit as randomized
b->bad_bit &= ~0x80000000;
LFS_EMUBD_TRACE("lfs_emubd_randomizebadbit -> %d", 0);
return 0;
}
int lfs_emubd_markbadbit(const struct lfs_config *cfg,
lfs_block_t block, lfs_size_t bit) {
LFS_EMUBD_TRACE("lfs_emubd_markbadbit(%p, %"PRIu32", %"PRIu32")",
(void*)cfg, block, bit);
lfs_emubd_t *bd = cfg->context;
// check if block is valid
LFS_ASSERT(block < cfg->block_count);
// mutate the block
lfs_emubd_block_t *b = lfs_emubd_mutblock(cfg, bd->blocks[block]);
if (!b) {
LFS_EMUBD_TRACE("lfs_emubd_markbadbit -> %d", LFS_ERR_NOMEM);
return LFS_ERR_NOMEM;
}
bd->blocks[block] = b;
// set the wear
b->wear = -1;
// set the bad bit and mark as fixed
b->bad_bit = 0x80000000 | bit;
LFS_EMUBD_TRACE("lfs_emubd_markbadbit -> %d", 0);
return 0;
}
lfs_emubd_spowercycles_t lfs_emubd_powercycles(
const struct lfs_config *cfg) {
LFS_EMUBD_TRACE("lfs_emubd_powercycles(%p)", (void*)cfg);
lfs_emubd_t *bd = cfg->context;
LFS_EMUBD_TRACE("lfs_emubd_powercycles -> %"PRIi32, bd->power_cycles);
return bd->power_cycles;
}
int lfs_emubd_setpowercycles(const struct lfs_config *cfg,
lfs_emubd_powercycles_t power_cycles) {
LFS_EMUBD_TRACE("lfs_emubd_setpowercycles(%p, %"PRIi32")",
(void*)cfg, power_cycles);
lfs_emubd_t *bd = cfg->context;
bd->power_cycles = power_cycles;
LFS_EMUBD_TRACE("lfs_emubd_powercycles -> %d", 0);
return 0;
}
int lfs_emubd_copy(const struct lfs_config *cfg, lfs_emubd_t *copy) {
LFS_EMUBD_TRACE("lfs_emubd_copy(%p, %p)", (void*)cfg, (void*)copy);
lfs_emubd_t *bd = cfg->context;
// lazily copy over our block array
copy->blocks = malloc(
cfg->block_count * sizeof(lfs_emubd_block_t*));
if (!copy->blocks) {
LFS_EMUBD_TRACE("lfs_emubd_copy -> %d", LFS_ERR_NOMEM);
return LFS_ERR_NOMEM;
}
for (lfs_block_t i = 0; i < cfg->block_count; i++) {
copy->blocks[i] = lfs_emubd_incblock(bd->blocks[i]);
}
if (bd->cfg->powerloss_behavior == LFS_EMUBD_POWERLOSS_OOO) {
copy->ooo_before = malloc(
cfg->block_count * sizeof(lfs_emubd_block_t*));
if (!copy->ooo_before) {
LFS_EMUBD_TRACE("lfs_emubd_copy -> %d", LFS_ERR_NOMEM);
return LFS_ERR_NOMEM;
}
for (lfs_block_t i = 0; i < cfg->block_count; i++) {
copy->ooo_before[i] = lfs_emubd_incblock(bd->ooo_before[i]);
}
copy->ooo_after = malloc(
cfg->block_count * sizeof(lfs_emubd_block_t*));
if (!copy->ooo_after) {
LFS_EMUBD_TRACE("lfs_emubd_copy -> %d", LFS_ERR_NOMEM);
return LFS_ERR_NOMEM;
}
for (lfs_block_t i = 0; i < cfg->block_count; i++) {
copy->ooo_after[i] = lfs_emubd_incblock(bd->ooo_after[i]);
}
}
// other state
copy->readed = bd->readed;
copy->proged = bd->proged;
copy->erased = bd->erased;
copy->prng = bd->prng;
copy->power_cycles = bd->power_cycles;
copy->disk = bd->disk;
if (copy->disk) {
copy->disk->rc += 1;
}
copy->cfg = bd->cfg;
LFS_EMUBD_TRACE("lfs_emubd_copy -> %d", 0);
return 0;
}
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